[v5,2/6] remoteproc: pru: Add APIs to get and put the PRU cores

Commit Message

Puranjay Mohan June 7, 2022, 4:56 a.m. UTC

From: Tero Kristo <[e-mail]>

Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
driver to allow client drivers to acquire and release the remoteproc
device associated with a PRU core. The PRU cores are treated as
resources with only one client owning it at a time.

The pru_rproc_get() function returns the rproc handle corresponding
to a PRU core identified by the device tree "ti,prus" property under
the client node. The pru_rproc_put() is the complementary function
to pru_rproc_get().

Co-developed-by: Suman Anna <[e-mail]>
Signed-off-by: Suman Anna <[e-mail]>
Signed-off-by: Tero Kristo <[e-mail]>
Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
Co-developed-by: Puranjay Mohan <[e-mail]>
Signed-off-by: Puranjay Mohan <[e-mail]>
---
 drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
 include/linux/pruss.h          |  56 +++++++++++++
 2 files changed, 189 insertions(+), 5 deletions(-)
 create mode 100644 include/linux/pruss.h

Comments

Mathieu Poirier July 12, 2022, 5:59 p.m. UTC | #1

Hi Puranjay,

On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
> From: Tero Kristo <[e-mail]>
> 
> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
> driver to allow client drivers to acquire and release the remoteproc
> device associated with a PRU core. The PRU cores are treated as
> resources with only one client owning it at a time.
> 
> The pru_rproc_get() function returns the rproc handle corresponding
> to a PRU core identified by the device tree "ti,prus" property under
> the client node. The pru_rproc_put() is the complementary function
> to pru_rproc_get().
> 
> Co-developed-by: Suman Anna <[e-mail]>
> Signed-off-by: Suman Anna <[e-mail]>
> Signed-off-by: Tero Kristo <[e-mail]>
> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
> Co-developed-by: Puranjay Mohan <[e-mail]>
> Signed-off-by: Puranjay Mohan <[e-mail]>
> ---
>  drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>  include/linux/pruss.h          |  56 +++++++++++++
>  2 files changed, 189 insertions(+), 5 deletions(-)
>  create mode 100644 include/linux/pruss.h
> 
> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> index 1777a01fa84e..7a35b400287a 100644
> --- a/drivers/remoteproc/pru_rproc.c
> +++ b/drivers/remoteproc/pru_rproc.c
> @@ -2,12 +2,13 @@
>  /*
>   * PRU-ICSS remoteproc driver for various TI SoCs
>   *
> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>   *
>   * Author(s):
>   *	Suman Anna <[e-mail]>
>   *	Andrew F. Davis <[e-mail]>
>   *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
> + *	Puranjay Mohan <[e-mail]>
>   */
>  
>  #include <linux/bitops.h>
> @@ -16,6 +17,7 @@
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/of_irq.h>
> +#include <linux/pruss.h>
>  #include <linux/pruss_driver.h>
>  #include <linux/remoteproc.h>
>  
> @@ -111,6 +113,8 @@ struct pru_private_data {
>   * @rproc: remoteproc pointer for this PRU core
>   * @data: PRU core specific data
>   * @mem_regions: data for each of the PRU memory regions
> + * @client_np: client device node
> + * @lock: mutex to protect client usage
>   * @fw_name: name of firmware image used during loading
>   * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>   * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
> @@ -126,6 +130,8 @@ struct pru_rproc {
>  	struct rproc *rproc;
>  	const struct pru_private_data *data;
>  	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
> +	struct device_node *client_np;
> +	struct mutex lock; /* client access lock */
>  	const char *fw_name;
>  	unsigned int *mapped_irq;
>  	struct pru_irq_rsc *pru_interrupt_map;
> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>  	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>  }
>  
> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
> +{
> +	struct device_node *rproc_np = NULL;
> +	struct platform_device *pdev;
> +	struct rproc *rproc;
> +
> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
> +	if (!rproc_np || !of_device_is_available(rproc_np))
> +		return ERR_PTR(-ENODEV);
> +
> +	pdev = of_find_device_by_node(rproc_np);
> +	of_node_put(rproc_np);
> +
> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
> +		/* probably PRU not yet probed */
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	/* make sure it is PRU rproc */
> +	if (!is_pru_rproc(&pdev->dev)) {
> +		put_device(&pdev->dev);
> +		return ERR_PTR(-ENODEV);
> +	}
> +
> +	rproc = platform_get_drvdata(pdev);
> +	put_device(&pdev->dev);
> +	if (!rproc)
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	get_device(&rproc->dev);
> +
> +	return rproc;
> +}
> +
> +/**
> + * pru_rproc_get() - get the PRU rproc instance from a device node
> + * @np: the user/client device node
> + * @index: index to use for the ti,prus property
> + * @pru_id: optional pointer to return the PRU remoteproc processor id
> + *
> + * This function looks through a client device node's "ti,prus" property at
> + * index @index and returns the rproc handle for a valid PRU remote processor if
> + * found. The function allows only one user to own the PRU rproc resource at a
> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
> + * required if the function returns a failure.
> + *
> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
> + * returned.
> + *
> + * Return: rproc handle on success, and an ERR_PTR on failure using one
> + * of the following error values
> + *    -ENODEV if device is not found
> + *    -EBUSY if PRU is already acquired by anyone
> + *    -EPROBE_DEFER is PRU device is not probed yet
> + */
> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> +			    enum pruss_pru_id *pru_id)
> +{
> +	struct rproc *rproc;
> +	struct pru_rproc *pru;
> +	struct device *dev;
> +
> +	try_module_get(THIS_MODULE);

There should be a module_put() in pru_rproc_put()...

More comments to come tomorrow.  I'm especially worried about this API racing
with a remote processor being removed or detached.

Thanks,
Mathieu

> +
> +	rproc = __pru_rproc_get(np, index);
> +	if (IS_ERR(rproc))
> +		return rproc;
> +
> +	pru = rproc->priv;
> +	dev = &rproc->dev;
> +
> +	mutex_lock(&pru->lock);
> +
> +	if (pru->client_np) {
> +		mutex_unlock(&pru->lock);
> +		put_device(dev);
> +		return ERR_PTR(-EBUSY);
> +	}
> +
> +	pru->client_np = np;
> +
> +	mutex_unlock(&pru->lock);
> +
> +	if (pru_id)
> +		*pru_id = pru->id;
> +
> +	return rproc;
> +}
> +EXPORT_SYMBOL_GPL(pru_rproc_get);
> +
> +/**
> + * pru_rproc_put() - release the PRU rproc resource
> + * @rproc: the rproc resource to release
> + *
> + * Releases the PRU rproc resource and makes it available to other
> + * users.
> + */
> +void pru_rproc_put(struct rproc *rproc)
> +{
> +	struct pru_rproc *pru;
> +
> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
> +		return;
> +
> +	pru = rproc->priv;
> +
> +	mutex_lock(&pru->lock);
> +
> +	if (!pru->client_np) {
> +		mutex_unlock(&pru->lock);
> +		return;
> +	}
> +
> +	pru->client_np = NULL;
> +	mutex_unlock(&pru->lock);
> +
> +	put_device(&rproc->dev);
> +}
> +EXPORT_SYMBOL_GPL(pru_rproc_put);
> +
>  static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>  {
>  	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>  	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>  	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>  	/* PRU1 has its local RAM addresses reversed */
> -	if (pru->id == 1)
> +	if (pru->id == PRUSS_PRU1)
>  		swap(dram0, dram1);
>  	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>  
> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>  	case RTU0_IRAM_ADDR_MASK:
>  		fallthrough;
>  	case PRU0_IRAM_ADDR_MASK:
> -		pru->id = 0;
> +		pru->id = PRUSS_PRU0;
>  		break;
>  	case TX_PRU1_IRAM_ADDR_MASK:
>  		fallthrough;
>  	case RTU1_IRAM_ADDR_MASK:
>  		fallthrough;
>  	case PRU1_IRAM_ADDR_MASK:
> -		pru->id = 1;
> +		pru->id = PRUSS_PRU1;
>  		break;
>  	default:
>  		ret = -EINVAL;
> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>  	pru->pruss = platform_get_drvdata(ppdev);
>  	pru->rproc = rproc;
>  	pru->fw_name = fw_name;
> +	pru->client_np = NULL;
> +	mutex_init(&pru->lock);
>  
>  	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>  		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>  
>  static struct platform_driver pru_rproc_driver = {
>  	.driver = {
> -		.name   = "pru-rproc",
> +		.name   = PRU_RPROC_DRVNAME,
>  		.of_match_table = pru_rproc_match,
>  		.suppress_bind_attrs = true,
>  	},
> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>  MODULE_AUTHOR("Suman Anna <[e-mail]>");
>  MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>  MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>  MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>  MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
> new file mode 100644
> index 000000000000..fdc719b43db0
> --- /dev/null
> +++ b/include/linux/pruss.h
> @@ -0,0 +1,56 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/**
> + * PRU-ICSS Subsystem user interfaces
> + *
> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
> + *	Suman Anna <[e-mail]>
> + */
> +
> +#ifndef __LINUX_PRUSS_H
> +#define __LINUX_PRUSS_H
> +
> +#include <linux/device.h>
> +#include <linux/types.h>
> +
> +#define PRU_RPROC_DRVNAME "pru-rproc"
> +
> +/*
> + * enum pruss_pru_id - PRU core identifiers
> + */
> +enum pruss_pru_id {
> +	PRUSS_PRU0 = 0,
> +	PRUSS_PRU1,
> +	PRUSS_NUM_PRUS,
> +};
> +
> +struct device_node;
> +
> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> +
> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> +			    enum pruss_pru_id *pru_id);
> +void pru_rproc_put(struct rproc *rproc);
> +
> +#else
> +
> +static inline struct rproc *
> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
> +static inline void pru_rproc_put(struct rproc *rproc) { }
> +
> +#endif /* CONFIG_PRU_REMOTEPROC */
> +
> +static inline bool is_pru_rproc(struct device *dev)
> +{
> +	const char *drv_name = dev_driver_string(dev);
> +
> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
> +		return false;
> +
> +	return true;
> +}
> +
> +#endif /* __LINUX_PRUSS_H */
> -- 
> 2.17.1
>

Mathieu Poirier July 14, 2022, 5:20 p.m. UTC | #2

On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
> Hi Puranjay,
> 
> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
> > From: Tero Kristo <[e-mail]>
> > 
> > Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
> > driver to allow client drivers to acquire and release the remoteproc
> > device associated with a PRU core. The PRU cores are treated as
> > resources with only one client owning it at a time.
> > 
> > The pru_rproc_get() function returns the rproc handle corresponding
> > to a PRU core identified by the device tree "ti,prus" property under
> > the client node. The pru_rproc_put() is the complementary function
> > to pru_rproc_get().
> > 
> > Co-developed-by: Suman Anna <[e-mail]>
> > Signed-off-by: Suman Anna <[e-mail]>
> > Signed-off-by: Tero Kristo <[e-mail]>
> > Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
> > Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
> > Co-developed-by: Puranjay Mohan <[e-mail]>
> > Signed-off-by: Puranjay Mohan <[e-mail]>
> > ---
> >  drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
> >  include/linux/pruss.h          |  56 +++++++++++++
> >  2 files changed, 189 insertions(+), 5 deletions(-)
> >  create mode 100644 include/linux/pruss.h
> > 
> > diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> > index 1777a01fa84e..7a35b400287a 100644
> > --- a/drivers/remoteproc/pru_rproc.c
> > +++ b/drivers/remoteproc/pru_rproc.c
> > @@ -2,12 +2,13 @@
> >  /*
> >   * PRU-ICSS remoteproc driver for various TI SoCs
> >   *
> > - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
> > + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
> >   *
> >   * Author(s):
> >   *	Suman Anna <[e-mail]>
> >   *	Andrew F. Davis <[e-mail]>
> >   *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
> > + *	Puranjay Mohan <[e-mail]>
> >   */
> >  
> >  #include <linux/bitops.h>
> > @@ -16,6 +17,7 @@
> >  #include <linux/module.h>
> >  #include <linux/of_device.h>
> >  #include <linux/of_irq.h>
> > +#include <linux/pruss.h>
> >  #include <linux/pruss_driver.h>
> >  #include <linux/remoteproc.h>
> >  
> > @@ -111,6 +113,8 @@ struct pru_private_data {
> >   * @rproc: remoteproc pointer for this PRU core
> >   * @data: PRU core specific data
> >   * @mem_regions: data for each of the PRU memory regions
> > + * @client_np: client device node
> > + * @lock: mutex to protect client usage
> >   * @fw_name: name of firmware image used during loading
> >   * @mapped_irq: virtual interrupt numbers of created fw specific mapping
> >   * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
> > @@ -126,6 +130,8 @@ struct pru_rproc {
> >  	struct rproc *rproc;
> >  	const struct pru_private_data *data;
> >  	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
> > +	struct device_node *client_np;
> > +	struct mutex lock; /* client access lock */
> >  	const char *fw_name;
> >  	unsigned int *mapped_irq;
> >  	struct pru_irq_rsc *pru_interrupt_map;
> > @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
> >  	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
> >  }
> >  
> > +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
> > +{
> > +	struct device_node *rproc_np = NULL;
> > +	struct platform_device *pdev;
> > +	struct rproc *rproc;
> > +
> > +	rproc_np = of_parse_phandle(np, "ti,prus", index);
> > +	if (!rproc_np || !of_device_is_available(rproc_np))
> > +		return ERR_PTR(-ENODEV);
> > +
> > +	pdev = of_find_device_by_node(rproc_np);
> > +	of_node_put(rproc_np);
> > +
> > +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
> > +		/* probably PRU not yet probed */
> > +		return ERR_PTR(-EPROBE_DEFER);
> > +
> > +	/* make sure it is PRU rproc */
> > +	if (!is_pru_rproc(&pdev->dev)) {
> > +		put_device(&pdev->dev);
> > +		return ERR_PTR(-ENODEV);
> > +	}
> > +
> > +	rproc = platform_get_drvdata(pdev);
> > +	put_device(&pdev->dev);
> > +	if (!rproc)
> > +		return ERR_PTR(-EPROBE_DEFER);
> > +
> > +	get_device(&rproc->dev);
> > +
> > +	return rproc;
> > +}
> > +
> > +/**
> > + * pru_rproc_get() - get the PRU rproc instance from a device node
> > + * @np: the user/client device node
> > + * @index: index to use for the ti,prus property
> > + * @pru_id: optional pointer to return the PRU remoteproc processor id
> > + *
> > + * This function looks through a client device node's "ti,prus" property at
> > + * index @index and returns the rproc handle for a valid PRU remote processor if
> > + * found. The function allows only one user to own the PRU rproc resource at a
> > + * time. Caller must call pru_rproc_put() when done with using the rproc, not
> > + * required if the function returns a failure.
> > + *
> > + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
> > + * returned.
> > + *
> > + * Return: rproc handle on success, and an ERR_PTR on failure using one
> > + * of the following error values
> > + *    -ENODEV if device is not found
> > + *    -EBUSY if PRU is already acquired by anyone
> > + *    -EPROBE_DEFER is PRU device is not probed yet
> > + */
> > +struct rproc *pru_rproc_get(struct device_node *np, int index,
> > +			    enum pruss_pru_id *pru_id)
> > +{
> > +	struct rproc *rproc;
> > +	struct pru_rproc *pru;
> > +	struct device *dev;
> > +
> > +	try_module_get(THIS_MODULE);
> 
> There should be a module_put() in pru_rproc_put()...

... and in the error path of this function.

> 
> More comments to come tomorrow.  I'm especially worried about this API racing
> with a remote processor being removed or detached.
>

Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
rproc_get_by_handle() here and that would make sure the remote processor doesn't
go away before the end of the function.

More comments to come...


> Thanks,
> Mathieu
> 
> > +
> > +	rproc = __pru_rproc_get(np, index);
> > +	if (IS_ERR(rproc))
> > +		return rproc;
> > +
> > +	pru = rproc->priv;
> > +	dev = &rproc->dev;
> > +
> > +	mutex_lock(&pru->lock);
> > +
> > +	if (pru->client_np) {
> > +		mutex_unlock(&pru->lock);
> > +		put_device(dev);
> > +		return ERR_PTR(-EBUSY);
> > +	}
> > +
> > +	pru->client_np = np;
> > +
> > +	mutex_unlock(&pru->lock);
> > +
> > +	if (pru_id)
> > +		*pru_id = pru->id;
> > +
> > +	return rproc;
> > +}
> > +EXPORT_SYMBOL_GPL(pru_rproc_get);
> > +
> > +/**
> > + * pru_rproc_put() - release the PRU rproc resource
> > + * @rproc: the rproc resource to release
> > + *
> > + * Releases the PRU rproc resource and makes it available to other
> > + * users.
> > + */
> > +void pru_rproc_put(struct rproc *rproc)
> > +{
> > +	struct pru_rproc *pru;
> > +
> > +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
> > +		return;
> > +
> > +	pru = rproc->priv;
> > +
> > +	mutex_lock(&pru->lock);
> > +
> > +	if (!pru->client_np) {
> > +		mutex_unlock(&pru->lock);
> > +		return;
> > +	}
> > +
> > +	pru->client_np = NULL;
> > +	mutex_unlock(&pru->lock);
> > +
> > +	put_device(&rproc->dev);
> > +}
> > +EXPORT_SYMBOL_GPL(pru_rproc_put);
> > +
> >  static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
> >  {
> >  	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
> > @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
> >  	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
> >  	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
> >  	/* PRU1 has its local RAM addresses reversed */
> > -	if (pru->id == 1)
> > +	if (pru->id == PRUSS_PRU1)
> >  		swap(dram0, dram1);
> >  	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
> >  
> > @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
> >  	case RTU0_IRAM_ADDR_MASK:
> >  		fallthrough;
> >  	case PRU0_IRAM_ADDR_MASK:
> > -		pru->id = 0;
> > +		pru->id = PRUSS_PRU0;
> >  		break;
> >  	case TX_PRU1_IRAM_ADDR_MASK:
> >  		fallthrough;
> >  	case RTU1_IRAM_ADDR_MASK:
> >  		fallthrough;
> >  	case PRU1_IRAM_ADDR_MASK:
> > -		pru->id = 1;
> > +		pru->id = PRUSS_PRU1;
> >  		break;
> >  	default:
> >  		ret = -EINVAL;
> > @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
> >  	pru->pruss = platform_get_drvdata(ppdev);
> >  	pru->rproc = rproc;
> >  	pru->fw_name = fw_name;
> > +	pru->client_np = NULL;
> > +	mutex_init(&pru->lock);
> >  
> >  	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
> >  		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
> >  
> >  static struct platform_driver pru_rproc_driver = {
> >  	.driver = {
> > -		.name   = "pru-rproc",
> > +		.name   = PRU_RPROC_DRVNAME,
> >  		.of_match_table = pru_rproc_match,
> >  		.suppress_bind_attrs = true,
> >  	},
> > @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
> >  MODULE_AUTHOR("Suman Anna <[e-mail]>");
> >  MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
> >  MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
> > +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
> >  MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
> >  MODULE_LICENSE("GPL v2");
> > diff --git a/include/linux/pruss.h b/include/linux/pruss.h
> > new file mode 100644
> > index 000000000000..fdc719b43db0
> > --- /dev/null
> > +++ b/include/linux/pruss.h
> > @@ -0,0 +1,56 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/**
> > + * PRU-ICSS Subsystem user interfaces
> > + *
> > + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
> > + *	Suman Anna <[e-mail]>
> > + */
> > +
> > +#ifndef __LINUX_PRUSS_H
> > +#define __LINUX_PRUSS_H
> > +
> > +#include <linux/device.h>
> > +#include <linux/types.h>
> > +
> > +#define PRU_RPROC_DRVNAME "pru-rproc"
> > +
> > +/*
> > + * enum pruss_pru_id - PRU core identifiers
> > + */
> > +enum pruss_pru_id {
> > +	PRUSS_PRU0 = 0,
> > +	PRUSS_PRU1,
> > +	PRUSS_NUM_PRUS,
> > +};
> > +
> > +struct device_node;
> > +
> > +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> > +
> > +struct rproc *pru_rproc_get(struct device_node *np, int index,
> > +			    enum pruss_pru_id *pru_id);
> > +void pru_rproc_put(struct rproc *rproc);
> > +
> > +#else
> > +
> > +static inline struct rproc *
> > +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
> > +{
> > +	return ERR_PTR(-EOPNOTSUPP);
> > +}
> > +
> > +static inline void pru_rproc_put(struct rproc *rproc) { }
> > +
> > +#endif /* CONFIG_PRU_REMOTEPROC */
> > +
> > +static inline bool is_pru_rproc(struct device *dev)
> > +{
> > +	const char *drv_name = dev_driver_string(dev);
> > +
> > +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
> > +		return false;
> > +
> > +	return true;
> > +}
> > +
> > +#endif /* __LINUX_PRUSS_H */
> > -- 
> > 2.17.1
> >

Kishon Vijay Abraham I July 15, 2022, 6:22 a.m. UTC | #3

+Danish

Hi Mathieu,

On 14/07/22 22:50, Mathieu Poirier wrote:
> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>> Hi Puranjay,

Removed Puranjay (as he is no longer with TI) and adding Danish.

Regards,
Kishon
>>
>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>> From: Tero Kristo <[e-mail]>
>>>
>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>> driver to allow client drivers to acquire and release the remoteproc
>>> device associated with a PRU core. The PRU cores are treated as
>>> resources with only one client owning it at a time.
>>>
>>> The pru_rproc_get() function returns the rproc handle corresponding
>>> to a PRU core identified by the device tree "ti,prus" property under
>>> the client node. The pru_rproc_put() is the complementary function
>>> to pru_rproc_get().
>>>
>>> Co-developed-by: Suman Anna <[e-mail]>
>>> Signed-off-by: Suman Anna <[e-mail]>
>>> Signed-off-by: Tero Kristo <[e-mail]>
>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>> ---
>>>  drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>  include/linux/pruss.h          |  56 +++++++++++++
>>>  2 files changed, 189 insertions(+), 5 deletions(-)
>>>  create mode 100644 include/linux/pruss.h
>>>
>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>> index 1777a01fa84e..7a35b400287a 100644
>>> --- a/drivers/remoteproc/pru_rproc.c
>>> +++ b/drivers/remoteproc/pru_rproc.c
>>> @@ -2,12 +2,13 @@
>>>  /*
>>>   * PRU-ICSS remoteproc driver for various TI SoCs
>>>   *
>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>   *
>>>   * Author(s):
>>>   *	Suman Anna <[e-mail]>
>>>   *	Andrew F. Davis <[e-mail]>
>>>   *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>> + *	Puranjay Mohan <[e-mail]>
>>>   */
>>>  
>>>  #include <linux/bitops.h>
>>> @@ -16,6 +17,7 @@
>>>  #include <linux/module.h>
>>>  #include <linux/of_device.h>
>>>  #include <linux/of_irq.h>
>>> +#include <linux/pruss.h>
>>>  #include <linux/pruss_driver.h>
>>>  #include <linux/remoteproc.h>
>>>  
>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>   * @rproc: remoteproc pointer for this PRU core
>>>   * @data: PRU core specific data
>>>   * @mem_regions: data for each of the PRU memory regions
>>> + * @client_np: client device node
>>> + * @lock: mutex to protect client usage
>>>   * @fw_name: name of firmware image used during loading
>>>   * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>   * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>  	struct rproc *rproc;
>>>  	const struct pru_private_data *data;
>>>  	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>> +	struct device_node *client_np;
>>> +	struct mutex lock; /* client access lock */
>>>  	const char *fw_name;
>>>  	unsigned int *mapped_irq;
>>>  	struct pru_irq_rsc *pru_interrupt_map;
>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>  	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>  }
>>>  
>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>> +{
>>> +	struct device_node *rproc_np = NULL;
>>> +	struct platform_device *pdev;
>>> +	struct rproc *rproc;
>>> +
>>> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
>>> +	if (!rproc_np || !of_device_is_available(rproc_np))
>>> +		return ERR_PTR(-ENODEV);
>>> +
>>> +	pdev = of_find_device_by_node(rproc_np);
>>> +	of_node_put(rproc_np);
>>> +
>>> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>> +		/* probably PRU not yet probed */
>>> +		return ERR_PTR(-EPROBE_DEFER);
>>> +
>>> +	/* make sure it is PRU rproc */
>>> +	if (!is_pru_rproc(&pdev->dev)) {
>>> +		put_device(&pdev->dev);
>>> +		return ERR_PTR(-ENODEV);
>>> +	}
>>> +
>>> +	rproc = platform_get_drvdata(pdev);
>>> +	put_device(&pdev->dev);
>>> +	if (!rproc)
>>> +		return ERR_PTR(-EPROBE_DEFER);
>>> +
>>> +	get_device(&rproc->dev);
>>> +
>>> +	return rproc;
>>> +}
>>> +
>>> +/**
>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>> + * @np: the user/client device node
>>> + * @index: index to use for the ti,prus property
>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>> + *
>>> + * This function looks through a client device node's "ti,prus" property at
>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>> + * required if the function returns a failure.
>>> + *
>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>> + * returned.
>>> + *
>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>> + * of the following error values
>>> + *    -ENODEV if device is not found
>>> + *    -EBUSY if PRU is already acquired by anyone
>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>> + */
>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>> +			    enum pruss_pru_id *pru_id)
>>> +{
>>> +	struct rproc *rproc;
>>> +	struct pru_rproc *pru;
>>> +	struct device *dev;
>>> +
>>> +	try_module_get(THIS_MODULE);
>>
>> There should be a module_put() in pru_rproc_put()...
> 
> ... and in the error path of this function.
> 
>>
>> More comments to come tomorrow.  I'm especially worried about this API racing
>> with a remote processor being removed or detached.
>>
> 
> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
> rproc_get_by_handle() here and that would make sure the remote processor doesn't
> go away before the end of the function.
> 
> More comments to come...
> 
> 
>> Thanks,
>> Mathieu
>>
>>> +
>>> +	rproc = __pru_rproc_get(np, index);
>>> +	if (IS_ERR(rproc))
>>> +		return rproc;
>>> +
>>> +	pru = rproc->priv;
>>> +	dev = &rproc->dev;
>>> +
>>> +	mutex_lock(&pru->lock);
>>> +
>>> +	if (pru->client_np) {
>>> +		mutex_unlock(&pru->lock);
>>> +		put_device(dev);
>>> +		return ERR_PTR(-EBUSY);
>>> +	}
>>> +
>>> +	pru->client_np = np;
>>> +
>>> +	mutex_unlock(&pru->lock);
>>> +
>>> +	if (pru_id)
>>> +		*pru_id = pru->id;
>>> +
>>> +	return rproc;
>>> +}
>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>> +
>>> +/**
>>> + * pru_rproc_put() - release the PRU rproc resource
>>> + * @rproc: the rproc resource to release
>>> + *
>>> + * Releases the PRU rproc resource and makes it available to other
>>> + * users.
>>> + */
>>> +void pru_rproc_put(struct rproc *rproc)
>>> +{
>>> +	struct pru_rproc *pru;
>>> +
>>> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>> +		return;
>>> +
>>> +	pru = rproc->priv;
>>> +
>>> +	mutex_lock(&pru->lock);
>>> +
>>> +	if (!pru->client_np) {
>>> +		mutex_unlock(&pru->lock);
>>> +		return;
>>> +	}
>>> +
>>> +	pru->client_np = NULL;
>>> +	mutex_unlock(&pru->lock);
>>> +
>>> +	put_device(&rproc->dev);
>>> +}
>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>> +
>>>  static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>  {
>>>  	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>  	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>  	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>  	/* PRU1 has its local RAM addresses reversed */
>>> -	if (pru->id == 1)
>>> +	if (pru->id == PRUSS_PRU1)
>>>  		swap(dram0, dram1);
>>>  	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>  
>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>  	case RTU0_IRAM_ADDR_MASK:
>>>  		fallthrough;
>>>  	case PRU0_IRAM_ADDR_MASK:
>>> -		pru->id = 0;
>>> +		pru->id = PRUSS_PRU0;
>>>  		break;
>>>  	case TX_PRU1_IRAM_ADDR_MASK:
>>>  		fallthrough;
>>>  	case RTU1_IRAM_ADDR_MASK:
>>>  		fallthrough;
>>>  	case PRU1_IRAM_ADDR_MASK:
>>> -		pru->id = 1;
>>> +		pru->id = PRUSS_PRU1;
>>>  		break;
>>>  	default:
>>>  		ret = -EINVAL;
>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>  	pru->pruss = platform_get_drvdata(ppdev);
>>>  	pru->rproc = rproc;
>>>  	pru->fw_name = fw_name;
>>> +	pru->client_np = NULL;
>>> +	mutex_init(&pru->lock);
>>>  
>>>  	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>  		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>  
>>>  static struct platform_driver pru_rproc_driver = {
>>>  	.driver = {
>>> -		.name   = "pru-rproc",
>>> +		.name   = PRU_RPROC_DRVNAME,
>>>  		.of_match_table = pru_rproc_match,
>>>  		.suppress_bind_attrs = true,
>>>  	},
>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>  MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>  MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>  MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>  MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>  MODULE_LICENSE("GPL v2");
>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>> new file mode 100644
>>> index 000000000000..fdc719b43db0
>>> --- /dev/null
>>> +++ b/include/linux/pruss.h
>>> @@ -0,0 +1,56 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +/**
>>> + * PRU-ICSS Subsystem user interfaces
>>> + *
>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>> + *	Suman Anna <[e-mail]>
>>> + */
>>> +
>>> +#ifndef __LINUX_PRUSS_H
>>> +#define __LINUX_PRUSS_H
>>> +
>>> +#include <linux/device.h>
>>> +#include <linux/types.h>
>>> +
>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>> +
>>> +/*
>>> + * enum pruss_pru_id - PRU core identifiers
>>> + */
>>> +enum pruss_pru_id {
>>> +	PRUSS_PRU0 = 0,
>>> +	PRUSS_PRU1,
>>> +	PRUSS_NUM_PRUS,
>>> +};
>>> +
>>> +struct device_node;
>>> +
>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>> +
>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>> +			    enum pruss_pru_id *pru_id);
>>> +void pru_rproc_put(struct rproc *rproc);
>>> +
>>> +#else
>>> +
>>> +static inline struct rproc *
>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>> +{
>>> +	return ERR_PTR(-EOPNOTSUPP);
>>> +}
>>> +
>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>> +
>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>> +
>>> +static inline bool is_pru_rproc(struct device *dev)
>>> +{
>>> +	const char *drv_name = dev_driver_string(dev);
>>> +
>>> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>> +		return false;
>>> +
>>> +	return true;
>>> +}
>>> +
>>> +#endif /* __LINUX_PRUSS_H */
>>> -- 
>>> 2.17.1
>>>

Anwar, Md Danish Sept. 2, 2022, 9:39 a.m. UTC | #4

Hi Mathieu,


On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
> +Danish
> 
> Hi Mathieu,
> 
> On 14/07/22 22:50, Mathieu Poirier wrote:
>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>>> Hi Puranjay,
> 
> Removed Puranjay (as he is no longer with TI) and adding Danish.
> 
> Regards,
> Kishon
>>>
>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>>> From: Tero Kristo <[e-mail]>
>>>>
>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>>> driver to allow client drivers to acquire and release the remoteproc
>>>> device associated with a PRU core. The PRU cores are treated as
>>>> resources with only one client owning it at a time.
>>>>
>>>> The pru_rproc_get() function returns the rproc handle corresponding
>>>> to a PRU core identified by the device tree "ti,prus" property under
>>>> the client node. The pru_rproc_put() is the complementary function
>>>> to pru_rproc_get().
>>>>
>>>> Co-developed-by: Suman Anna <[e-mail]>
>>>> Signed-off-by: Suman Anna <[e-mail]>
>>>> Signed-off-by: Tero Kristo <[e-mail]>
>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>>> ---
>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>>   include/linux/pruss.h          |  56 +++++++++++++
>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
>>>>   create mode 100644 include/linux/pruss.h
>>>>
>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>>> index 1777a01fa84e..7a35b400287a 100644
>>>> --- a/drivers/remoteproc/pru_rproc.c
>>>> +++ b/drivers/remoteproc/pru_rproc.c
>>>> @@ -2,12 +2,13 @@
>>>>   /*
>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
>>>>    *
>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>>    *
>>>>    * Author(s):
>>>>    *	Suman Anna <[e-mail]>
>>>>    *	Andrew F. Davis <[e-mail]>
>>>>    *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>>> + *	Puranjay Mohan <[e-mail]>
>>>>    */
>>>>   
>>>>   #include <linux/bitops.h>
>>>> @@ -16,6 +17,7 @@
>>>>   #include <linux/module.h>
>>>>   #include <linux/of_device.h>
>>>>   #include <linux/of_irq.h>
>>>> +#include <linux/pruss.h>
>>>>   #include <linux/pruss_driver.h>
>>>>   #include <linux/remoteproc.h>
>>>>   
>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>>    * @rproc: remoteproc pointer for this PRU core
>>>>    * @data: PRU core specific data
>>>>    * @mem_regions: data for each of the PRU memory regions
>>>> + * @client_np: client device node
>>>> + * @lock: mutex to protect client usage
>>>>    * @fw_name: name of firmware image used during loading
>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>>   	struct rproc *rproc;
>>>>   	const struct pru_private_data *data;
>>>>   	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>>> +	struct device_node *client_np;
>>>> +	struct mutex lock; /* client access lock */
>>>>   	const char *fw_name;
>>>>   	unsigned int *mapped_irq;
>>>>   	struct pru_irq_rsc *pru_interrupt_map;
>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>>   	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>>   }
>>>>   
>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>>> +{
>>>> +	struct device_node *rproc_np = NULL;
>>>> +	struct platform_device *pdev;
>>>> +	struct rproc *rproc;
>>>> +
>>>> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
>>>> +	if (!rproc_np || !of_device_is_available(rproc_np))
>>>> +		return ERR_PTR(-ENODEV);
>>>> +
>>>> +	pdev = of_find_device_by_node(rproc_np);
>>>> +	of_node_put(rproc_np);
>>>> +
>>>> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>>> +		/* probably PRU not yet probed */
>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>> +
>>>> +	/* make sure it is PRU rproc */
>>>> +	if (!is_pru_rproc(&pdev->dev)) {
>>>> +		put_device(&pdev->dev);
>>>> +		return ERR_PTR(-ENODEV);
>>>> +	}
>>>> +
>>>> +	rproc = platform_get_drvdata(pdev);
>>>> +	put_device(&pdev->dev);
>>>> +	if (!rproc)
>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>> +
>>>> +	get_device(&rproc->dev);
>>>> +
>>>> +	return rproc;
>>>> +}
>>>> +
>>>> +/**
>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>>> + * @np: the user/client device node
>>>> + * @index: index to use for the ti,prus property
>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>>> + *
>>>> + * This function looks through a client device node's "ti,prus" property at
>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>>> + * required if the function returns a failure.
>>>> + *
>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>>> + * returned.
>>>> + *
>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>>> + * of the following error values
>>>> + *    -ENODEV if device is not found
>>>> + *    -EBUSY if PRU is already acquired by anyone
>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>>> + */
>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>> +			    enum pruss_pru_id *pru_id)
>>>> +{
>>>> +	struct rproc *rproc;
>>>> +	struct pru_rproc *pru;
>>>> +	struct device *dev;
>>>> +
>>>> +	try_module_get(THIS_MODULE);
>>>
>>> There should be a module_put() in pru_rproc_put()...
>>
>> ... and in the error path of this function.
>>
>>>
>>> More comments to come tomorrow.  I'm especially worried about this API racing
>>> with a remote processor being removed or detached.
>>>
>>
>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
>> go away before the end of the function.
>>
>> More comments to come...

It is possible to call rproc_get_by_handle() here instead of 
__pru_get_proc(), but that would not provide multiple functionality.

The API rproc_get_by_handle() returns rproc handle on success, and NULL 
on failure where as __pru_get_proc() returns ERR_PTR on failure which 
provides multiple functionality and opportunity for us to distinguish 
between multiple errors.

So we have these three options.

1. If we're using the API rproc_get_by_handle() and we want the multiple 
ERR_PTR on failure then we will need to change the API 
rproc_get_by_handle() and also all the functions that uses 
rproc_get_by_handle().

2. Keep the API rproc_get_by_handle() as it is. That will restrict us 
from using multiple ERR_PTR on different kinds of error.

3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). 
This will make sure we have the proper ERR_PTR to retrun for different 
kinds of errors.

Please let me know which option to continue with.

Thanks,
Danish


>>
>>
>>> Thanks,
>>> Mathieu
>>>
>>>> +
>>>> +	rproc = __pru_rproc_get(np, index);
>>>> +	if (IS_ERR(rproc))
>>>> +		return rproc;
>>>> +
>>>> +	pru = rproc->priv;
>>>> +	dev = &rproc->dev;
>>>> +
>>>> +	mutex_lock(&pru->lock);
>>>> +
>>>> +	if (pru->client_np) {
>>>> +		mutex_unlock(&pru->lock);
>>>> +		put_device(dev);
>>>> +		return ERR_PTR(-EBUSY);
>>>> +	}
>>>> +
>>>> +	pru->client_np = np;
>>>> +
>>>> +	mutex_unlock(&pru->lock);
>>>> +
>>>> +	if (pru_id)
>>>> +		*pru_id = pru->id;
>>>> +
>>>> +	return rproc;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>>> +
>>>> +/**
>>>> + * pru_rproc_put() - release the PRU rproc resource
>>>> + * @rproc: the rproc resource to release
>>>> + *
>>>> + * Releases the PRU rproc resource and makes it available to other
>>>> + * users.
>>>> + */
>>>> +void pru_rproc_put(struct rproc *rproc)
>>>> +{
>>>> +	struct pru_rproc *pru;
>>>> +
>>>> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>>> +		return;
>>>> +
>>>> +	pru = rproc->priv;
>>>> +
>>>> +	mutex_lock(&pru->lock);
>>>> +
>>>> +	if (!pru->client_np) {
>>>> +		mutex_unlock(&pru->lock);
>>>> +		return;
>>>> +	}
>>>> +
>>>> +	pru->client_np = NULL;
>>>> +	mutex_unlock(&pru->lock);
>>>> +
>>>> +	put_device(&rproc->dev);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>>> +
>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>>   {
>>>>   	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>>   	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>>   	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>>   	/* PRU1 has its local RAM addresses reversed */
>>>> -	if (pru->id == 1)
>>>> +	if (pru->id == PRUSS_PRU1)
>>>>   		swap(dram0, dram1);
>>>>   	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>>   
>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>>   	case RTU0_IRAM_ADDR_MASK:
>>>>   		fallthrough;
>>>>   	case PRU0_IRAM_ADDR_MASK:
>>>> -		pru->id = 0;
>>>> +		pru->id = PRUSS_PRU0;
>>>>   		break;
>>>>   	case TX_PRU1_IRAM_ADDR_MASK:
>>>>   		fallthrough;
>>>>   	case RTU1_IRAM_ADDR_MASK:
>>>>   		fallthrough;
>>>>   	case PRU1_IRAM_ADDR_MASK:
>>>> -		pru->id = 1;
>>>> +		pru->id = PRUSS_PRU1;
>>>>   		break;
>>>>   	default:
>>>>   		ret = -EINVAL;
>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>>   	pru->pruss = platform_get_drvdata(ppdev);
>>>>   	pru->rproc = rproc;
>>>>   	pru->fw_name = fw_name;
>>>> +	pru->client_np = NULL;
>>>> +	mutex_init(&pru->lock);
>>>>   
>>>>   	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>>   		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>>   
>>>>   static struct platform_driver pru_rproc_driver = {
>>>>   	.driver = {
>>>> -		.name   = "pru-rproc",
>>>> +		.name   = PRU_RPROC_DRVNAME,
>>>>   		.of_match_table = pru_rproc_match,
>>>>   		.suppress_bind_attrs = true,
>>>>   	},
>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>>   MODULE_LICENSE("GPL v2");
>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>>> new file mode 100644
>>>> index 000000000000..fdc719b43db0
>>>> --- /dev/null
>>>> +++ b/include/linux/pruss.h
>>>> @@ -0,0 +1,56 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>> +/**
>>>> + * PRU-ICSS Subsystem user interfaces
>>>> + *
>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>>> + *	Suman Anna <[e-mail]>
>>>> + */
>>>> +
>>>> +#ifndef __LINUX_PRUSS_H
>>>> +#define __LINUX_PRUSS_H
>>>> +
>>>> +#include <linux/device.h>
>>>> +#include <linux/types.h>
>>>> +
>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>>> +
>>>> +/*
>>>> + * enum pruss_pru_id - PRU core identifiers
>>>> + */
>>>> +enum pruss_pru_id {
>>>> +	PRUSS_PRU0 = 0,
>>>> +	PRUSS_PRU1,
>>>> +	PRUSS_NUM_PRUS,
>>>> +};
>>>> +
>>>> +struct device_node;
>>>> +
>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>>> +
>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>> +			    enum pruss_pru_id *pru_id);
>>>> +void pru_rproc_put(struct rproc *rproc);
>>>> +
>>>> +#else
>>>> +
>>>> +static inline struct rproc *
>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>>> +{
>>>> +	return ERR_PTR(-EOPNOTSUPP);
>>>> +}
>>>> +
>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>>> +
>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>>> +
>>>> +static inline bool is_pru_rproc(struct device *dev)
>>>> +{
>>>> +	const char *drv_name = dev_driver_string(dev);
>>>> +
>>>> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>>> +		return false;
>>>> +
>>>> +	return true;
>>>> +}
>>>> +
>>>> +#endif /* __LINUX_PRUSS_H */
>>>> -- 
>>>> 2.17.1
>>>>

Mathieu Poirier Sept. 6, 2022, 7:28 p.m. UTC | #5

On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
> Hi Mathieu,
> 
> 
> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
> > +Danish
> > 
> > Hi Mathieu,
> > 
> > On 14/07/22 22:50, Mathieu Poirier wrote:
> > > On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
> > > > Hi Puranjay,
> > 
> > Removed Puranjay (as he is no longer with TI) and adding Danish.
> > 
> > Regards,
> > Kishon
> > > > 
> > > > On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
> > > > > From: Tero Kristo <[e-mail]>
> > > > > 
> > > > > Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
> > > > > driver to allow client drivers to acquire and release the remoteproc
> > > > > device associated with a PRU core. The PRU cores are treated as
> > > > > resources with only one client owning it at a time.
> > > > > 
> > > > > The pru_rproc_get() function returns the rproc handle corresponding
> > > > > to a PRU core identified by the device tree "ti,prus" property under
> > > > > the client node. The pru_rproc_put() is the complementary function
> > > > > to pru_rproc_get().
> > > > > 
> > > > > Co-developed-by: Suman Anna <[e-mail]>
> > > > > Signed-off-by: Suman Anna <[e-mail]>
> > > > > Signed-off-by: Tero Kristo <[e-mail]>
> > > > > Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
> > > > > Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
> > > > > Co-developed-by: Puranjay Mohan <[e-mail]>
> > > > > Signed-off-by: Puranjay Mohan <[e-mail]>
> > > > > ---
> > > > >   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
> > > > >   include/linux/pruss.h          |  56 +++++++++++++
> > > > >   2 files changed, 189 insertions(+), 5 deletions(-)
> > > > >   create mode 100644 include/linux/pruss.h
> > > > > 
> > > > > diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> > > > > index 1777a01fa84e..7a35b400287a 100644
> > > > > --- a/drivers/remoteproc/pru_rproc.c
> > > > > +++ b/drivers/remoteproc/pru_rproc.c
> > > > > @@ -2,12 +2,13 @@
> > > > >   /*
> > > > >    * PRU-ICSS remoteproc driver for various TI SoCs
> > > > >    *
> > > > > - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
> > > > > + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
> > > > >    *
> > > > >    * Author(s):
> > > > >    *	Suman Anna <[e-mail]>
> > > > >    *	Andrew F. Davis <[e-mail]>
> > > > >    *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
> > > > > + *	Puranjay Mohan <[e-mail]>
> > > > >    */
> > > > >   #include <linux/bitops.h>
> > > > > @@ -16,6 +17,7 @@
> > > > >   #include <linux/module.h>
> > > > >   #include <linux/of_device.h>
> > > > >   #include <linux/of_irq.h>
> > > > > +#include <linux/pruss.h>
> > > > >   #include <linux/pruss_driver.h>
> > > > >   #include <linux/remoteproc.h>
> > > > > @@ -111,6 +113,8 @@ struct pru_private_data {
> > > > >    * @rproc: remoteproc pointer for this PRU core
> > > > >    * @data: PRU core specific data
> > > > >    * @mem_regions: data for each of the PRU memory regions
> > > > > + * @client_np: client device node
> > > > > + * @lock: mutex to protect client usage
> > > > >    * @fw_name: name of firmware image used during loading
> > > > >    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
> > > > >    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
> > > > > @@ -126,6 +130,8 @@ struct pru_rproc {
> > > > >   	struct rproc *rproc;
> > > > >   	const struct pru_private_data *data;
> > > > >   	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
> > > > > +	struct device_node *client_np;
> > > > > +	struct mutex lock; /* client access lock */
> > > > >   	const char *fw_name;
> > > > >   	unsigned int *mapped_irq;
> > > > >   	struct pru_irq_rsc *pru_interrupt_map;
> > > > > @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
> > > > >   	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
> > > > >   }
> > > > > +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
> > > > > +{
> > > > > +	struct device_node *rproc_np = NULL;
> > > > > +	struct platform_device *pdev;
> > > > > +	struct rproc *rproc;
> > > > > +
> > > > > +	rproc_np = of_parse_phandle(np, "ti,prus", index);
> > > > > +	if (!rproc_np || !of_device_is_available(rproc_np))
> > > > > +		return ERR_PTR(-ENODEV);
> > > > > +
> > > > > +	pdev = of_find_device_by_node(rproc_np);
> > > > > +	of_node_put(rproc_np);
> > > > > +
> > > > > +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
> > > > > +		/* probably PRU not yet probed */
> > > > > +		return ERR_PTR(-EPROBE_DEFER);
> > > > > +
> > > > > +	/* make sure it is PRU rproc */
> > > > > +	if (!is_pru_rproc(&pdev->dev)) {
> > > > > +		put_device(&pdev->dev);
> > > > > +		return ERR_PTR(-ENODEV);
> > > > > +	}
> > > > > +
> > > > > +	rproc = platform_get_drvdata(pdev);
> > > > > +	put_device(&pdev->dev);
> > > > > +	if (!rproc)
> > > > > +		return ERR_PTR(-EPROBE_DEFER);
> > > > > +
> > > > > +	get_device(&rproc->dev);
> > > > > +
> > > > > +	return rproc;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * pru_rproc_get() - get the PRU rproc instance from a device node
> > > > > + * @np: the user/client device node
> > > > > + * @index: index to use for the ti,prus property
> > > > > + * @pru_id: optional pointer to return the PRU remoteproc processor id
> > > > > + *
> > > > > + * This function looks through a client device node's "ti,prus" property at
> > > > > + * index @index and returns the rproc handle for a valid PRU remote processor if
> > > > > + * found. The function allows only one user to own the PRU rproc resource at a
> > > > > + * time. Caller must call pru_rproc_put() when done with using the rproc, not
> > > > > + * required if the function returns a failure.
> > > > > + *
> > > > > + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
> > > > > + * returned.
> > > > > + *
> > > > > + * Return: rproc handle on success, and an ERR_PTR on failure using one
> > > > > + * of the following error values
> > > > > + *    -ENODEV if device is not found
> > > > > + *    -EBUSY if PRU is already acquired by anyone
> > > > > + *    -EPROBE_DEFER is PRU device is not probed yet
> > > > > + */
> > > > > +struct rproc *pru_rproc_get(struct device_node *np, int index,
> > > > > +			    enum pruss_pru_id *pru_id)
> > > > > +{
> > > > > +	struct rproc *rproc;
> > > > > +	struct pru_rproc *pru;
> > > > > +	struct device *dev;
> > > > > +
> > > > > +	try_module_get(THIS_MODULE);
> > > > 
> > > > There should be a module_put() in pru_rproc_put()...
> > > 
> > > ... and in the error path of this function.
> > > 
> > > > 
> > > > More comments to come tomorrow.  I'm especially worried about this API racing
> > > > with a remote processor being removed or detached.
> > > > 
> > > 
> > > Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
> > > rproc_get_by_handle() here and that would make sure the remote processor doesn't
> > > go away before the end of the function.
> > > 
> > > More comments to come...
> 
> It is possible to call rproc_get_by_handle() here instead of
> __pru_get_proc(), but that would not provide multiple functionality.
> 
> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
> multiple functionality and opportunity for us to distinguish between
> multiple errors.
> 
> So we have these three options.
> 
> 1. If we're using the API rproc_get_by_handle() and we want the multiple
> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
> and also all the functions that uses rproc_get_by_handle().
>

Not optimal.

> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
> using multiple ERR_PTR on different kinds of error.
> 

Not optimal.

> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
> will make sure we have the proper ERR_PTR to retrun for different kinds of
> errors.
> 

Unacceptable for the reason I already stated.  

> Please let me know which option to continue with.

I suggest building a wrapper that does everything you want around rproc_get_by_phandle().

> 
> Thanks,
> Danish
> 
> 
> > > 
> > > 
> > > > Thanks,
> > > > Mathieu
> > > > 
> > > > > +
> > > > > +	rproc = __pru_rproc_get(np, index);
> > > > > +	if (IS_ERR(rproc))
> > > > > +		return rproc;
> > > > > +
> > > > > +	pru = rproc->priv;
> > > > > +	dev = &rproc->dev;
> > > > > +
> > > > > +	mutex_lock(&pru->lock);
> > > > > +
> > > > > +	if (pru->client_np) {
> > > > > +		mutex_unlock(&pru->lock);
> > > > > +		put_device(dev);
> > > > > +		return ERR_PTR(-EBUSY);
> > > > > +	}
> > > > > +
> > > > > +	pru->client_np = np;
> > > > > +
> > > > > +	mutex_unlock(&pru->lock);
> > > > > +
> > > > > +	if (pru_id)
> > > > > +		*pru_id = pru->id;
> > > > > +
> > > > > +	return rproc;
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(pru_rproc_get);
> > > > > +
> > > > > +/**
> > > > > + * pru_rproc_put() - release the PRU rproc resource
> > > > > + * @rproc: the rproc resource to release
> > > > > + *
> > > > > + * Releases the PRU rproc resource and makes it available to other
> > > > > + * users.
> > > > > + */
> > > > > +void pru_rproc_put(struct rproc *rproc)
> > > > > +{
> > > > > +	struct pru_rproc *pru;
> > > > > +
> > > > > +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
> > > > > +		return;
> > > > > +
> > > > > +	pru = rproc->priv;
> > > > > +
> > > > > +	mutex_lock(&pru->lock);
> > > > > +
> > > > > +	if (!pru->client_np) {
> > > > > +		mutex_unlock(&pru->lock);
> > > > > +		return;
> > > > > +	}
> > > > > +
> > > > > +	pru->client_np = NULL;
> > > > > +	mutex_unlock(&pru->lock);
> > > > > +
> > > > > +	put_device(&rproc->dev);
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(pru_rproc_put);
> > > > > +
> > > > >   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
> > > > >   {
> > > > >   	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
> > > > > @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
> > > > >   	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
> > > > >   	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
> > > > >   	/* PRU1 has its local RAM addresses reversed */
> > > > > -	if (pru->id == 1)
> > > > > +	if (pru->id == PRUSS_PRU1)
> > > > >   		swap(dram0, dram1);
> > > > >   	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
> > > > > @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
> > > > >   	case RTU0_IRAM_ADDR_MASK:
> > > > >   		fallthrough;
> > > > >   	case PRU0_IRAM_ADDR_MASK:
> > > > > -		pru->id = 0;
> > > > > +		pru->id = PRUSS_PRU0;
> > > > >   		break;
> > > > >   	case TX_PRU1_IRAM_ADDR_MASK:
> > > > >   		fallthrough;
> > > > >   	case RTU1_IRAM_ADDR_MASK:
> > > > >   		fallthrough;
> > > > >   	case PRU1_IRAM_ADDR_MASK:
> > > > > -		pru->id = 1;
> > > > > +		pru->id = PRUSS_PRU1;
> > > > >   		break;
> > > > >   	default:
> > > > >   		ret = -EINVAL;
> > > > > @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
> > > > >   	pru->pruss = platform_get_drvdata(ppdev);
> > > > >   	pru->rproc = rproc;
> > > > >   	pru->fw_name = fw_name;
> > > > > +	pru->client_np = NULL;
> > > > > +	mutex_init(&pru->lock);
> > > > >   	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
> > > > >   		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > > > > @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
> > > > >   static struct platform_driver pru_rproc_driver = {
> > > > >   	.driver = {
> > > > > -		.name   = "pru-rproc",
> > > > > +		.name   = PRU_RPROC_DRVNAME,
> > > > >   		.of_match_table = pru_rproc_match,
> > > > >   		.suppress_bind_attrs = true,
> > > > >   	},
> > > > > @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
> > > > >   MODULE_AUTHOR("Suman Anna <[e-mail]>");
> > > > >   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
> > > > >   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
> > > > > +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
> > > > >   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
> > > > >   MODULE_LICENSE("GPL v2");
> > > > > diff --git a/include/linux/pruss.h b/include/linux/pruss.h
> > > > > new file mode 100644
> > > > > index 000000000000..fdc719b43db0
> > > > > --- /dev/null
> > > > > +++ b/include/linux/pruss.h
> > > > > @@ -0,0 +1,56 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > > > +/**
> > > > > + * PRU-ICSS Subsystem user interfaces
> > > > > + *
> > > > > + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
> > > > > + *	Suman Anna <[e-mail]>
> > > > > + */
> > > > > +
> > > > > +#ifndef __LINUX_PRUSS_H
> > > > > +#define __LINUX_PRUSS_H
> > > > > +
> > > > > +#include <linux/device.h>
> > > > > +#include <linux/types.h>
> > > > > +
> > > > > +#define PRU_RPROC_DRVNAME "pru-rproc"
> > > > > +
> > > > > +/*
> > > > > + * enum pruss_pru_id - PRU core identifiers
> > > > > + */
> > > > > +enum pruss_pru_id {
> > > > > +	PRUSS_PRU0 = 0,
> > > > > +	PRUSS_PRU1,
> > > > > +	PRUSS_NUM_PRUS,
> > > > > +};
> > > > > +
> > > > > +struct device_node;
> > > > > +
> > > > > +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> > > > > +
> > > > > +struct rproc *pru_rproc_get(struct device_node *np, int index,
> > > > > +			    enum pruss_pru_id *pru_id);
> > > > > +void pru_rproc_put(struct rproc *rproc);
> > > > > +
> > > > > +#else
> > > > > +
> > > > > +static inline struct rproc *
> > > > > +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
> > > > > +{
> > > > > +	return ERR_PTR(-EOPNOTSUPP);
> > > > > +}
> > > > > +
> > > > > +static inline void pru_rproc_put(struct rproc *rproc) { }
> > > > > +
> > > > > +#endif /* CONFIG_PRU_REMOTEPROC */
> > > > > +
> > > > > +static inline bool is_pru_rproc(struct device *dev)
> > > > > +{
> > > > > +	const char *drv_name = dev_driver_string(dev);
> > > > > +
> > > > > +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
> > > > > +		return false;
> > > > > +
> > > > > +	return true;
> > > > > +}
> > > > > +
> > > > > +#endif /* __LINUX_PRUSS_H */
> > > > > -- 
> > > > > 2.17.1
> > > > >

Anwar, Md Danish Sept. 7, 2022, 9:24 a.m. UTC | #6

Hi Mathieu,

On 07/09/22 00:58, Mathieu Poirier wrote:
> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
>> Hi Mathieu,
>>
>>
>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
>>> +Danish
>>>
>>> Hi Mathieu,
>>>
>>> On 14/07/22 22:50, Mathieu Poirier wrote:
>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>>>>> Hi Puranjay,
>>>
>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
>>>
>>> Regards,
>>> Kishon
>>>>>
>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>>>>> From: Tero Kristo <[e-mail]>
>>>>>>
>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>>>>> driver to allow client drivers to acquire and release the remoteproc
>>>>>> device associated with a PRU core. The PRU cores are treated as
>>>>>> resources with only one client owning it at a time.
>>>>>>
>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
>>>>>> to a PRU core identified by the device tree "ti,prus" property under
>>>>>> the client node. The pru_rproc_put() is the complementary function
>>>>>> to pru_rproc_get().
>>>>>>
>>>>>> Co-developed-by: Suman Anna <[e-mail]>
>>>>>> Signed-off-by: Suman Anna <[e-mail]>
>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>>>>> ---
>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
>>>>>>   create mode 100644 include/linux/pruss.h
>>>>>>
>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>>>>> index 1777a01fa84e..7a35b400287a 100644
>>>>>> --- a/drivers/remoteproc/pru_rproc.c
>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
>>>>>> @@ -2,12 +2,13 @@
>>>>>>   /*
>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
>>>>>>    *
>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>    *
>>>>>>    * Author(s):
>>>>>>    *	Suman Anna <[e-mail]>
>>>>>>    *	Andrew F. Davis <[e-mail]>
>>>>>>    *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>>>>> + *	Puranjay Mohan <[e-mail]>
>>>>>>    */
>>>>>>   #include <linux/bitops.h>
>>>>>> @@ -16,6 +17,7 @@
>>>>>>   #include <linux/module.h>
>>>>>>   #include <linux/of_device.h>
>>>>>>   #include <linux/of_irq.h>
>>>>>> +#include <linux/pruss.h>
>>>>>>   #include <linux/pruss_driver.h>
>>>>>>   #include <linux/remoteproc.h>
>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>>>>    * @rproc: remoteproc pointer for this PRU core
>>>>>>    * @data: PRU core specific data
>>>>>>    * @mem_regions: data for each of the PRU memory regions
>>>>>> + * @client_np: client device node
>>>>>> + * @lock: mutex to protect client usage
>>>>>>    * @fw_name: name of firmware image used during loading
>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>>>>   	struct rproc *rproc;
>>>>>>   	const struct pru_private_data *data;
>>>>>>   	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>>>>> +	struct device_node *client_np;
>>>>>> +	struct mutex lock; /* client access lock */
>>>>>>   	const char *fw_name;
>>>>>>   	unsigned int *mapped_irq;
>>>>>>   	struct pru_irq_rsc *pru_interrupt_map;
>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>>>>   	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>>>>   }
>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>>>>> +{
>>>>>> +	struct device_node *rproc_np = NULL;
>>>>>> +	struct platform_device *pdev;
>>>>>> +	struct rproc *rproc;
>>>>>> +
>>>>>> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
>>>>>> +	if (!rproc_np || !of_device_is_available(rproc_np))
>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>> +
>>>>>> +	pdev = of_find_device_by_node(rproc_np);
>>>>>> +	of_node_put(rproc_np);
>>>>>> +
>>>>>> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>>>>> +		/* probably PRU not yet probed */
>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>> +
>>>>>> +	/* make sure it is PRU rproc */
>>>>>> +	if (!is_pru_rproc(&pdev->dev)) {
>>>>>> +		put_device(&pdev->dev);
>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>> +	}
>>>>>> +
>>>>>> +	rproc = platform_get_drvdata(pdev);
>>>>>> +	put_device(&pdev->dev);
>>>>>> +	if (!rproc)
>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>> +
>>>>>> +	get_device(&rproc->dev);
>>>>>> +
>>>>>> +	return rproc;
>>>>>> +}
>>>>>> +
>>>>>> +/**
>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>>>>> + * @np: the user/client device node
>>>>>> + * @index: index to use for the ti,prus property
>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>>>>> + *
>>>>>> + * This function looks through a client device node's "ti,prus" property at
>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>>>>> + * required if the function returns a failure.
>>>>>> + *
>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>>>>> + * returned.
>>>>>> + *
>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>>>>> + * of the following error values
>>>>>> + *    -ENODEV if device is not found
>>>>>> + *    -EBUSY if PRU is already acquired by anyone
>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>>>>> + */
>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>> +			    enum pruss_pru_id *pru_id)
>>>>>> +{
>>>>>> +	struct rproc *rproc;
>>>>>> +	struct pru_rproc *pru;
>>>>>> +	struct device *dev;
>>>>>> +
>>>>>> +	try_module_get(THIS_MODULE);
>>>>>
>>>>> There should be a module_put() in pru_rproc_put()...
>>>>
>>>> ... and in the error path of this function.
>>>>
>>>>>
>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
>>>>> with a remote processor being removed or detached.
>>>>>
>>>>
>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
>>>> go away before the end of the function.
>>>>
>>>> More comments to come...
>>
>> It is possible to call rproc_get_by_handle() here instead of
>> __pru_get_proc(), but that would not provide multiple functionality.
>>
>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
>> multiple functionality and opportunity for us to distinguish between
>> multiple errors.
>>
>> So we have these three options.
>>
>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
>> and also all the functions that uses rproc_get_by_handle().
>>
> 
> Not optimal.
> 
>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
>> using multiple ERR_PTR on different kinds of error.
>>
> 
> Not optimal.
> 
>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
>> will make sure we have the proper ERR_PTR to retrun for different kinds of
>> errors.
>>
> 
> Unacceptable for the reason I already stated.  
> 
>> Please let me know which option to continue with.
> 
> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().
> 

Sure, I'll do that. I'll share this change in v6 of this patch series.

>>
>> Thanks,
>> Danish
>>
>>
>>>>
>>>>
>>>>> Thanks,
>>>>> Mathieu
>>>>>
>>>>>> +
>>>>>> +	rproc = __pru_rproc_get(np, index);
>>>>>> +	if (IS_ERR(rproc))
>>>>>> +		return rproc;
>>>>>> +
>>>>>> +	pru = rproc->priv;
>>>>>> +	dev = &rproc->dev;
>>>>>> +
>>>>>> +	mutex_lock(&pru->lock);
>>>>>> +
>>>>>> +	if (pru->client_np) {
>>>>>> +		mutex_unlock(&pru->lock);
>>>>>> +		put_device(dev);
>>>>>> +		return ERR_PTR(-EBUSY);
>>>>>> +	}
>>>>>> +
>>>>>> +	pru->client_np = np;
>>>>>> +
>>>>>> +	mutex_unlock(&pru->lock);
>>>>>> +
>>>>>> +	if (pru_id)
>>>>>> +		*pru_id = pru->id;
>>>>>> +
>>>>>> +	return rproc;
>>>>>> +}
>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>>>>> +
>>>>>> +/**
>>>>>> + * pru_rproc_put() - release the PRU rproc resource
>>>>>> + * @rproc: the rproc resource to release
>>>>>> + *
>>>>>> + * Releases the PRU rproc resource and makes it available to other
>>>>>> + * users.
>>>>>> + */
>>>>>> +void pru_rproc_put(struct rproc *rproc)
>>>>>> +{
>>>>>> +	struct pru_rproc *pru;
>>>>>> +
>>>>>> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>>>>> +		return;
>>>>>> +
>>>>>> +	pru = rproc->priv;
>>>>>> +
>>>>>> +	mutex_lock(&pru->lock);
>>>>>> +
>>>>>> +	if (!pru->client_np) {
>>>>>> +		mutex_unlock(&pru->lock);
>>>>>> +		return;
>>>>>> +	}
>>>>>> +
>>>>>> +	pru->client_np = NULL;
>>>>>> +	mutex_unlock(&pru->lock);
>>>>>> +
>>>>>> +	put_device(&rproc->dev);
>>>>>> +}
>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>>>>> +
>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>>>>   {
>>>>>>   	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>>>>   	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>>>>   	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>>>>   	/* PRU1 has its local RAM addresses reversed */
>>>>>> -	if (pru->id == 1)
>>>>>> +	if (pru->id == PRUSS_PRU1)
>>>>>>   		swap(dram0, dram1);
>>>>>>   	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>>>>   	case RTU0_IRAM_ADDR_MASK:
>>>>>>   		fallthrough;
>>>>>>   	case PRU0_IRAM_ADDR_MASK:
>>>>>> -		pru->id = 0;
>>>>>> +		pru->id = PRUSS_PRU0;
>>>>>>   		break;
>>>>>>   	case TX_PRU1_IRAM_ADDR_MASK:
>>>>>>   		fallthrough;
>>>>>>   	case RTU1_IRAM_ADDR_MASK:
>>>>>>   		fallthrough;
>>>>>>   	case PRU1_IRAM_ADDR_MASK:
>>>>>> -		pru->id = 1;
>>>>>> +		pru->id = PRUSS_PRU1;
>>>>>>   		break;
>>>>>>   	default:
>>>>>>   		ret = -EINVAL;
>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>>>>   	pru->pruss = platform_get_drvdata(ppdev);
>>>>>>   	pru->rproc = rproc;
>>>>>>   	pru->fw_name = fw_name;
>>>>>> +	pru->client_np = NULL;
>>>>>> +	mutex_init(&pru->lock);
>>>>>>   	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>>>>   		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>>>>   static struct platform_driver pru_rproc_driver = {
>>>>>>   	.driver = {
>>>>>> -		.name   = "pru-rproc",
>>>>>> +		.name   = PRU_RPROC_DRVNAME,
>>>>>>   		.of_match_table = pru_rproc_match,
>>>>>>   		.suppress_bind_attrs = true,
>>>>>>   	},
>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>>>>   MODULE_LICENSE("GPL v2");
>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>>>>> new file mode 100644
>>>>>> index 000000000000..fdc719b43db0
>>>>>> --- /dev/null
>>>>>> +++ b/include/linux/pruss.h
>>>>>> @@ -0,0 +1,56 @@
>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>>>> +/**
>>>>>> + * PRU-ICSS Subsystem user interfaces
>>>>>> + *
>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>>>>> + *	Suman Anna <[e-mail]>
>>>>>> + */
>>>>>> +
>>>>>> +#ifndef __LINUX_PRUSS_H
>>>>>> +#define __LINUX_PRUSS_H
>>>>>> +
>>>>>> +#include <linux/device.h>
>>>>>> +#include <linux/types.h>
>>>>>> +
>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>>>>> +
>>>>>> +/*
>>>>>> + * enum pruss_pru_id - PRU core identifiers
>>>>>> + */
>>>>>> +enum pruss_pru_id {
>>>>>> +	PRUSS_PRU0 = 0,
>>>>>> +	PRUSS_PRU1,
>>>>>> +	PRUSS_NUM_PRUS,
>>>>>> +};
>>>>>> +
>>>>>> +struct device_node;
>>>>>> +
>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>>>>> +
>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>> +			    enum pruss_pru_id *pru_id);
>>>>>> +void pru_rproc_put(struct rproc *rproc);
>>>>>> +
>>>>>> +#else
>>>>>> +
>>>>>> +static inline struct rproc *
>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>>>>> +{
>>>>>> +	return ERR_PTR(-EOPNOTSUPP);
>>>>>> +}
>>>>>> +
>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>>>>> +
>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>>>>> +
>>>>>> +static inline bool is_pru_rproc(struct device *dev)
>>>>>> +{
>>>>>> +	const char *drv_name = dev_driver_string(dev);
>>>>>> +
>>>>>> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>>>>> +		return false;
>>>>>> +
>>>>>> +	return true;
>>>>>> +}
>>>>>> +
>>>>>> +#endif /* __LINUX_PRUSS_H */
>>>>>> -- 
>>>>>> 2.17.1
>>>>>>

Romain Naour Sept. 12, 2022, 1:24 p.m. UTC | #7

Hi Danish, All,

Le 07/09/2022 à 11:24, Md Danish Anwar a écrit :
> Hi Mathieu,
> 
> On 07/09/22 00:58, Mathieu Poirier wrote:
>> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
>>> Hi Mathieu,
>>>
>>>
>>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
>>>> +Danish
>>>>
>>>> Hi Mathieu,
>>>>
>>>> On 14/07/22 22:50, Mathieu Poirier wrote:
>>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>>>>>> Hi Puranjay,
>>>>
>>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
>>>>
>>>> Regards,
>>>> Kishon
>>>>>>
>>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>>>>>> From: Tero Kristo <[e-mail]>
>>>>>>>
>>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>>>>>> driver to allow client drivers to acquire and release the remoteproc
>>>>>>> device associated with a PRU core. The PRU cores are treated as
>>>>>>> resources with only one client owning it at a time.
>>>>>>>
>>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
>>>>>>> to a PRU core identified by the device tree "ti,prus" property under
>>>>>>> the client node. The pru_rproc_put() is the complementary function
>>>>>>> to pru_rproc_get().
>>>>>>>
>>>>>>> Co-developed-by: Suman Anna <[e-mail]>
>>>>>>> Signed-off-by: Suman Anna <[e-mail]>
>>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
>>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>>>>>> ---
>>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
>>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
>>>>>>>   create mode 100644 include/linux/pruss.h
>>>>>>>
>>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>>>>>> index 1777a01fa84e..7a35b400287a 100644
>>>>>>> --- a/drivers/remoteproc/pru_rproc.c
>>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
>>>>>>> @@ -2,12 +2,13 @@
>>>>>>>   /*
>>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
>>>>>>>    *
>>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>>    *
>>>>>>>    * Author(s):
>>>>>>>    *	Suman Anna <[e-mail]>
>>>>>>>    *	Andrew F. Davis <[e-mail]>
>>>>>>>    *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>>>>>> + *	Puranjay Mohan <[e-mail]>
>>>>>>>    */
>>>>>>>   #include <linux/bitops.h>
>>>>>>> @@ -16,6 +17,7 @@
>>>>>>>   #include <linux/module.h>
>>>>>>>   #include <linux/of_device.h>
>>>>>>>   #include <linux/of_irq.h>
>>>>>>> +#include <linux/pruss.h>
>>>>>>>   #include <linux/pruss_driver.h>
>>>>>>>   #include <linux/remoteproc.h>
>>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>>>>>    * @rproc: remoteproc pointer for this PRU core
>>>>>>>    * @data: PRU core specific data
>>>>>>>    * @mem_regions: data for each of the PRU memory regions
>>>>>>> + * @client_np: client device node
>>>>>>> + * @lock: mutex to protect client usage
>>>>>>>    * @fw_name: name of firmware image used during loading
>>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>>>>>   	struct rproc *rproc;
>>>>>>>   	const struct pru_private_data *data;
>>>>>>>   	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>>>>>> +	struct device_node *client_np;
>>>>>>> +	struct mutex lock; /* client access lock */
>>>>>>>   	const char *fw_name;
>>>>>>>   	unsigned int *mapped_irq;
>>>>>>>   	struct pru_irq_rsc *pru_interrupt_map;
>>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>>>>>   	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>>>>>   }
>>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>>>>>> +{
>>>>>>> +	struct device_node *rproc_np = NULL;
>>>>>>> +	struct platform_device *pdev;
>>>>>>> +	struct rproc *rproc;
>>>>>>> +
>>>>>>> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
>>>>>>> +	if (!rproc_np || !of_device_is_available(rproc_np))
>>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>>> +
>>>>>>> +	pdev = of_find_device_by_node(rproc_np);
>>>>>>> +	of_node_put(rproc_np);
>>>>>>> +
>>>>>>> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>>>>>> +		/* probably PRU not yet probed */
>>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>>> +
>>>>>>> +	/* make sure it is PRU rproc */
>>>>>>> +	if (!is_pru_rproc(&pdev->dev)) {
>>>>>>> +		put_device(&pdev->dev);
>>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>>> +	}
>>>>>>> +
>>>>>>> +	rproc = platform_get_drvdata(pdev);
>>>>>>> +	put_device(&pdev->dev);
>>>>>>> +	if (!rproc)
>>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>>> +
>>>>>>> +	get_device(&rproc->dev);
>>>>>>> +
>>>>>>> +	return rproc;
>>>>>>> +}
>>>>>>> +
>>>>>>> +/**
>>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>>>>>> + * @np: the user/client device node
>>>>>>> + * @index: index to use for the ti,prus property
>>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>>>>>> + *
>>>>>>> + * This function looks through a client device node's "ti,prus" property at
>>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>>>>>> + * required if the function returns a failure.
>>>>>>> + *
>>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>>>>>> + * returned.
>>>>>>> + *
>>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>>>>>> + * of the following error values
>>>>>>> + *    -ENODEV if device is not found
>>>>>>> + *    -EBUSY if PRU is already acquired by anyone
>>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>>>>>> + */
>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>> +			    enum pruss_pru_id *pru_id)
>>>>>>> +{
>>>>>>> +	struct rproc *rproc;
>>>>>>> +	struct pru_rproc *pru;
>>>>>>> +	struct device *dev;
>>>>>>> +
>>>>>>> +	try_module_get(THIS_MODULE);
>>>>>>
>>>>>> There should be a module_put() in pru_rproc_put()...
>>>>>
>>>>> ... and in the error path of this function.
>>>>>
>>>>>>
>>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
>>>>>> with a remote processor being removed or detached.
>>>>>>
>>>>>
>>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
>>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
>>>>> go away before the end of the function.
>>>>>
>>>>> More comments to come...
>>>
>>> It is possible to call rproc_get_by_handle() here instead of
>>> __pru_get_proc(), but that would not provide multiple functionality.
>>>
>>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
>>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
>>> multiple functionality and opportunity for us to distinguish between
>>> multiple errors.
>>>
>>> So we have these three options.
>>>
>>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
>>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
>>> and also all the functions that uses rproc_get_by_handle().
>>>
>>
>> Not optimal.
>>
>>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
>>> using multiple ERR_PTR on different kinds of error.
>>>
>>
>> Not optimal.
>>
>>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
>>> will make sure we have the proper ERR_PTR to retrun for different kinds of
>>> errors.
>>>
>>
>> Unacceptable for the reason I already stated.  
>>
>>> Please let me know which option to continue with.
>>
>> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().
>>
> 
> Sure, I'll do that. I'll share this change in v6 of this patch series.

I'm able to test the TI prueth driver from the ti-linux-5.10.y tree [1] on a
AM5749 cpu (custom board). But I need a more recent kernel (at least 5.15) to
support other devices recently added to the Linux kernel (wifi6 module and an
ethernet switch). Also it would be nice if this driver is finally merged in the
Linux kernel.

Maybe I can help to test this series but I noticed it only provide the driver
for TI AM654x cpus [2]. Can you also provide patches for basic EMAC support with
the TI AM574x too? (I don't need advanced features like frame timestamping, HSR
etc).

Also, what about patches present in the ti-linux-kernel tree and not included
this this series? Especially patches that modify the kernel network stack [3]
(net/rpmsg: add support for new rpmsg sockets). Is this new socket protocol
really needed?

Notice the patch adding the rpmsg sockets [3] already conflict with the upstream
kernel since the AF_MCTP definition now use the value temporarly used by
AF_RPMSG [4].

Can you send an updated version of the complete series?

Thanks!

[1] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/log/?h=ti-linux-5.10.y

[2] https://lore.kernel.org/linux-remoteproc/[e-mail]/

[3]
https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=f4b978a978c38149f712ddd137f12ed5fb914161

[4]
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc49d8169aa72295104f1558830c568efb946315

Best regards,
Romain


> 
>>>
>>> Thanks,
>>> Danish
>>>
>>>
>>>>>
>>>>>
>>>>>> Thanks,
>>>>>> Mathieu
>>>>>>
>>>>>>> +
>>>>>>> +	rproc = __pru_rproc_get(np, index);
>>>>>>> +	if (IS_ERR(rproc))
>>>>>>> +		return rproc;
>>>>>>> +
>>>>>>> +	pru = rproc->priv;
>>>>>>> +	dev = &rproc->dev;
>>>>>>> +
>>>>>>> +	mutex_lock(&pru->lock);
>>>>>>> +
>>>>>>> +	if (pru->client_np) {
>>>>>>> +		mutex_unlock(&pru->lock);
>>>>>>> +		put_device(dev);
>>>>>>> +		return ERR_PTR(-EBUSY);
>>>>>>> +	}
>>>>>>> +
>>>>>>> +	pru->client_np = np;
>>>>>>> +
>>>>>>> +	mutex_unlock(&pru->lock);
>>>>>>> +
>>>>>>> +	if (pru_id)
>>>>>>> +		*pru_id = pru->id;
>>>>>>> +
>>>>>>> +	return rproc;
>>>>>>> +}
>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>>>>>> +
>>>>>>> +/**
>>>>>>> + * pru_rproc_put() - release the PRU rproc resource
>>>>>>> + * @rproc: the rproc resource to release
>>>>>>> + *
>>>>>>> + * Releases the PRU rproc resource and makes it available to other
>>>>>>> + * users.
>>>>>>> + */
>>>>>>> +void pru_rproc_put(struct rproc *rproc)
>>>>>>> +{
>>>>>>> +	struct pru_rproc *pru;
>>>>>>> +
>>>>>>> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>>>>>> +		return;
>>>>>>> +
>>>>>>> +	pru = rproc->priv;
>>>>>>> +
>>>>>>> +	mutex_lock(&pru->lock);
>>>>>>> +
>>>>>>> +	if (!pru->client_np) {
>>>>>>> +		mutex_unlock(&pru->lock);
>>>>>>> +		return;
>>>>>>> +	}
>>>>>>> +
>>>>>>> +	pru->client_np = NULL;
>>>>>>> +	mutex_unlock(&pru->lock);
>>>>>>> +
>>>>>>> +	put_device(&rproc->dev);
>>>>>>> +}
>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>>>>>> +
>>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>>>>>   {
>>>>>>>   	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>>>>>   	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>>>>>   	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>>>>>   	/* PRU1 has its local RAM addresses reversed */
>>>>>>> -	if (pru->id == 1)
>>>>>>> +	if (pru->id == PRUSS_PRU1)
>>>>>>>   		swap(dram0, dram1);
>>>>>>>   	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>>>>>   	case RTU0_IRAM_ADDR_MASK:
>>>>>>>   		fallthrough;
>>>>>>>   	case PRU0_IRAM_ADDR_MASK:
>>>>>>> -		pru->id = 0;
>>>>>>> +		pru->id = PRUSS_PRU0;
>>>>>>>   		break;
>>>>>>>   	case TX_PRU1_IRAM_ADDR_MASK:
>>>>>>>   		fallthrough;
>>>>>>>   	case RTU1_IRAM_ADDR_MASK:
>>>>>>>   		fallthrough;
>>>>>>>   	case PRU1_IRAM_ADDR_MASK:
>>>>>>> -		pru->id = 1;
>>>>>>> +		pru->id = PRUSS_PRU1;
>>>>>>>   		break;
>>>>>>>   	default:
>>>>>>>   		ret = -EINVAL;
>>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>>>>>   	pru->pruss = platform_get_drvdata(ppdev);
>>>>>>>   	pru->rproc = rproc;
>>>>>>>   	pru->fw_name = fw_name;
>>>>>>> +	pru->client_np = NULL;
>>>>>>> +	mutex_init(&pru->lock);
>>>>>>>   	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>>>>>   		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>>>>>   static struct platform_driver pru_rproc_driver = {
>>>>>>>   	.driver = {
>>>>>>> -		.name   = "pru-rproc",
>>>>>>> +		.name   = PRU_RPROC_DRVNAME,
>>>>>>>   		.of_match_table = pru_rproc_match,
>>>>>>>   		.suppress_bind_attrs = true,
>>>>>>>   	},
>>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>>>>>   MODULE_LICENSE("GPL v2");
>>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..fdc719b43db0
>>>>>>> --- /dev/null
>>>>>>> +++ b/include/linux/pruss.h
>>>>>>> @@ -0,0 +1,56 @@
>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>>>>> +/**
>>>>>>> + * PRU-ICSS Subsystem user interfaces
>>>>>>> + *
>>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>>>>>> + *	Suman Anna <[e-mail]>
>>>>>>> + */
>>>>>>> +
>>>>>>> +#ifndef __LINUX_PRUSS_H
>>>>>>> +#define __LINUX_PRUSS_H
>>>>>>> +
>>>>>>> +#include <linux/device.h>
>>>>>>> +#include <linux/types.h>
>>>>>>> +
>>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>>>>>> +
>>>>>>> +/*
>>>>>>> + * enum pruss_pru_id - PRU core identifiers
>>>>>>> + */
>>>>>>> +enum pruss_pru_id {
>>>>>>> +	PRUSS_PRU0 = 0,
>>>>>>> +	PRUSS_PRU1,
>>>>>>> +	PRUSS_NUM_PRUS,
>>>>>>> +};
>>>>>>> +
>>>>>>> +struct device_node;
>>>>>>> +
>>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>>>>>> +
>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>> +			    enum pruss_pru_id *pru_id);
>>>>>>> +void pru_rproc_put(struct rproc *rproc);
>>>>>>> +
>>>>>>> +#else
>>>>>>> +
>>>>>>> +static inline struct rproc *
>>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>>>>>> +{
>>>>>>> +	return ERR_PTR(-EOPNOTSUPP);
>>>>>>> +}
>>>>>>> +
>>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>>>>>> +
>>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>>>>>> +
>>>>>>> +static inline bool is_pru_rproc(struct device *dev)
>>>>>>> +{
>>>>>>> +	const char *drv_name = dev_driver_string(dev);
>>>>>>> +
>>>>>>> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>>>>>> +		return false;
>>>>>>> +
>>>>>>> +	return true;
>>>>>>> +}
>>>>>>> +
>>>>>>> +#endif /* __LINUX_PRUSS_H */
>>>>>>> -- 
>>>>>>> 2.17.1
>>>>>>>
>

Anwar, Md Danish Sept. 13, 2022, 11:40 a.m. UTC | #8

Hi Mathieu,

On 12/09/22 18:54, Romain Naour wrote:
> Hi Danish, All,
> 
> Le 07/09/2022 à 11:24, Md Danish Anwar a écrit :
>> Hi Mathieu,
>>
>> On 07/09/22 00:58, Mathieu Poirier wrote:
>>> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
>>>> Hi Mathieu,
>>>>
>>>>
>>>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
>>>>> +Danish
>>>>>
>>>>> Hi Mathieu,
>>>>>
>>>>> On 14/07/22 22:50, Mathieu Poirier wrote:
>>>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>>>>>>> Hi Puranjay,
>>>>>
>>>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
>>>>>
>>>>> Regards,
>>>>> Kishon
>>>>>>>
>>>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>>>>>>> From: Tero Kristo <[e-mail]>
>>>>>>>>
>>>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>>>>>>> driver to allow client drivers to acquire and release the remoteproc
>>>>>>>> device associated with a PRU core. The PRU cores are treated as
>>>>>>>> resources with only one client owning it at a time.
>>>>>>>>
>>>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
>>>>>>>> to a PRU core identified by the device tree "ti,prus" property under
>>>>>>>> the client node. The pru_rproc_put() is the complementary function
>>>>>>>> to pru_rproc_get().
>>>>>>>>
>>>>>>>> Co-developed-by: Suman Anna <[e-mail]>
>>>>>>>> Signed-off-by: Suman Anna <[e-mail]>
>>>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
>>>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>>>>>>> ---
>>>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
>>>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
>>>>>>>>   create mode 100644 include/linux/pruss.h
>>>>>>>>
>>>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>>>>>>> index 1777a01fa84e..7a35b400287a 100644
>>>>>>>> --- a/drivers/remoteproc/pru_rproc.c
>>>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
>>>>>>>> @@ -2,12 +2,13 @@
>>>>>>>>   /*
>>>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
>>>>>>>>    *
>>>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>>>    *
>>>>>>>>    * Author(s):
>>>>>>>>    *	Suman Anna <[e-mail]>
>>>>>>>>    *	Andrew F. Davis <[e-mail]>
>>>>>>>>    *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>>>>>>> + *	Puranjay Mohan <[e-mail]>
>>>>>>>>    */
>>>>>>>>   #include <linux/bitops.h>
>>>>>>>> @@ -16,6 +17,7 @@
>>>>>>>>   #include <linux/module.h>
>>>>>>>>   #include <linux/of_device.h>
>>>>>>>>   #include <linux/of_irq.h>
>>>>>>>> +#include <linux/pruss.h>
>>>>>>>>   #include <linux/pruss_driver.h>
>>>>>>>>   #include <linux/remoteproc.h>
>>>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>>>>>>    * @rproc: remoteproc pointer for this PRU core
>>>>>>>>    * @data: PRU core specific data
>>>>>>>>    * @mem_regions: data for each of the PRU memory regions
>>>>>>>> + * @client_np: client device node
>>>>>>>> + * @lock: mutex to protect client usage
>>>>>>>>    * @fw_name: name of firmware image used during loading
>>>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>>>>>>   	struct rproc *rproc;
>>>>>>>>   	const struct pru_private_data *data;
>>>>>>>>   	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>>>>>>> +	struct device_node *client_np;
>>>>>>>> +	struct mutex lock; /* client access lock */
>>>>>>>>   	const char *fw_name;
>>>>>>>>   	unsigned int *mapped_irq;
>>>>>>>>   	struct pru_irq_rsc *pru_interrupt_map;
>>>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>>>>>>   	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>>>>>>   }
>>>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>>>>>>> +{
>>>>>>>> +	struct device_node *rproc_np = NULL;
>>>>>>>> +	struct platform_device *pdev;
>>>>>>>> +	struct rproc *rproc;
>>>>>>>> +
>>>>>>>> +	rproc_np = of_parse_phandle(np, "ti,prus", index);
>>>>>>>> +	if (!rproc_np || !of_device_is_available(rproc_np))
>>>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>>>> +
>>>>>>>> +	pdev = of_find_device_by_node(rproc_np);
>>>>>>>> +	of_node_put(rproc_np);
>>>>>>>> +
>>>>>>>> +	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>>>>>>> +		/* probably PRU not yet probed */
>>>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>>>> +
>>>>>>>> +	/* make sure it is PRU rproc */
>>>>>>>> +	if (!is_pru_rproc(&pdev->dev)) {
>>>>>>>> +		put_device(&pdev->dev);
>>>>>>>> +		return ERR_PTR(-ENODEV);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	rproc = platform_get_drvdata(pdev);
>>>>>>>> +	put_device(&pdev->dev);
>>>>>>>> +	if (!rproc)
>>>>>>>> +		return ERR_PTR(-EPROBE_DEFER);
>>>>>>>> +
>>>>>>>> +	get_device(&rproc->dev);
>>>>>>>> +
>>>>>>>> +	return rproc;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +/**
>>>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>>>>>>> + * @np: the user/client device node
>>>>>>>> + * @index: index to use for the ti,prus property
>>>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>>>>>>> + *
>>>>>>>> + * This function looks through a client device node's "ti,prus" property at
>>>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>>>>>>> + * required if the function returns a failure.
>>>>>>>> + *
>>>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>>>>>>> + * returned.
>>>>>>>> + *
>>>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>>>>>>> + * of the following error values
>>>>>>>> + *    -ENODEV if device is not found
>>>>>>>> + *    -EBUSY if PRU is already acquired by anyone
>>>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>>>>>>> + */
>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>>> +			    enum pruss_pru_id *pru_id)
>>>>>>>> +{
>>>>>>>> +	struct rproc *rproc;
>>>>>>>> +	struct pru_rproc *pru;
>>>>>>>> +	struct device *dev;
>>>>>>>> +
>>>>>>>> +	try_module_get(THIS_MODULE);
>>>>>>>
>>>>>>> There should be a module_put() in pru_rproc_put()...
>>>>>>
>>>>>> ... and in the error path of this function.
>>>>>>
>>>>>>>
>>>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
>>>>>>> with a remote processor being removed or detached.
>>>>>>>
>>>>>>
>>>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
>>>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
>>>>>> go away before the end of the function.
>>>>>>
>>>>>> More comments to come...
>>>>
>>>> It is possible to call rproc_get_by_handle() here instead of
>>>> __pru_get_proc(), but that would not provide multiple functionality.
>>>>
>>>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
>>>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
>>>> multiple functionality and opportunity for us to distinguish between
>>>> multiple errors.
>>>>
>>>> So we have these three options.
>>>>
>>>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
>>>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
>>>> and also all the functions that uses rproc_get_by_handle().
>>>>
>>>
>>> Not optimal.
>>>
>>>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
>>>> using multiple ERR_PTR on different kinds of error.
>>>>
>>>
>>> Not optimal.
>>>
>>>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
>>>> will make sure we have the proper ERR_PTR to retrun for different kinds of
>>>> errors.
>>>>
>>>
>>> Unacceptable for the reason I already stated.  
>>>
>>>> Please let me know which option to continue with.
>>>
>>> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().

We can introduce a new API __rproc_get_by_phandle() similar to the API
rproc_get_by_phandle(). The new API __rproc_get_by_phandle() will do all the
functionality of getting the rproc. On success it will return rproc and on
failure it will return the different ERR_PTR.
If rproc is not probed yet, it will return ERR_PTR(-EPROBE_DEFER).

This will make sure that we're getting different error codes for different
errors from pru_rproc_get().

The old API rproc_get_by_handle() will invoke the new API. On success the new
API will return rproc and the old API will also return rproc. On failure the
new API will return different error codes while the old API will preserve it's
nature and return NULL.

The API __rproc_get_by_handle will look like this.

struct rproc *__rproc_get_by_handle(phandle phandle)
{
	struct rproc *rproc = NULL, *r;
	struct device_node *np;

	np = of_find_node_by_phandle(phandle);
	if (!np)
		return NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(r, &rproc_list, node) {
		if (r->dev.parent && r->dev.parent->of_node == np) {
			/*prevent underlying implementation from being removed */
			if (!try_module_get(r->dev.parent->driver->owner)) {
				dev_err(&r->dev, "can't get owner\n");
				break;
			}

			rproc = r;
			get_device(&rproc->dev);
			break;
		}
	}
	rcu_read_unlock();

	of_node_put(np);

	if(!rproc)
		return ERR_PTR(-EPROBE_DEFER);

	return rproc;
}

The API rproc_get_by_handle() will look like this.

struct rproc *rproc_get_by_phandle(phandle phandle)
{
	struct rproc *rproc = NULL;

	rproc = __rproc_get_by_handle(phandle);

	if(!rproc || IS_ERR(rproc))
		return NULL;

	return rproc;
}

This way in pru_rproc_get(), we'll get the rproc by phandle and we'll still
return different error codes depending upon failure cases. We'll also be able
to preserve the actual functionality of rproc_get_by_phandle() so that the
other APIs using rproc_get_by_phandle() won't get affected.

Please let me know if this looks good.

>>>
>>
>> Sure, I'll do that. I'll share this change in v6 of this patch series.
> 
> I'm able to test the TI prueth driver from the ti-linux-5.10.y tree [1] on a
> AM5749 cpu (custom board). But I need a more recent kernel (at least 5.15) to
> support other devices recently added to the Linux kernel (wifi6 module and an
> ethernet switch). Also it would be nice if this driver is finally merged in the
> Linux kernel.
> 
> Maybe I can help to test this series but I noticed it only provide the driver
> for TI AM654x cpus [2]. Can you also provide patches for basic EMAC support with
> the TI AM574x too? (I don't need advanced features like frame timestamping, HSR
> etc).
> 
> Also, what about patches present in the ti-linux-kernel tree and not included
> this this series? Especially patches that modify the kernel network stack [3]
> (net/rpmsg: add support for new rpmsg sockets). Is this new socket protocol
> really needed?
> 
> Notice the patch adding the rpmsg sockets [3] already conflict with the upstream
> kernel since the AF_MCTP definition now use the value temporarly used by
> AF_RPMSG [4].
> 
> Can you send an updated version of the complete series?
> 
> Thanks!
> 
> [1] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/log/?h=ti-linux-5.10.y
> 
> [2] https://lore.kernel.org/linux-remoteproc/[e-mail]/
> 
> [3]
> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=f4b978a978c38149f712ddd137f12ed5fb914161
> 
> [4]
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc49d8169aa72295104f1558830c568efb946315
> 
> Best regards,
> Romain
> 
> 
>>
>>>>
>>>> Thanks,
>>>> Danish
>>>>
>>>>
>>>>>>
>>>>>>
>>>>>>> Thanks,
>>>>>>> Mathieu
>>>>>>>
>>>>>>>> +
>>>>>>>> +	rproc = __pru_rproc_get(np, index);
>>>>>>>> +	if (IS_ERR(rproc))
>>>>>>>> +		return rproc;
>>>>>>>> +
>>>>>>>> +	pru = rproc->priv;
>>>>>>>> +	dev = &rproc->dev;
>>>>>>>> +
>>>>>>>> +	mutex_lock(&pru->lock);
>>>>>>>> +
>>>>>>>> +	if (pru->client_np) {
>>>>>>>> +		mutex_unlock(&pru->lock);
>>>>>>>> +		put_device(dev);
>>>>>>>> +		return ERR_PTR(-EBUSY);
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pru->client_np = np;
>>>>>>>> +
>>>>>>>> +	mutex_unlock(&pru->lock);
>>>>>>>> +
>>>>>>>> +	if (pru_id)
>>>>>>>> +		*pru_id = pru->id;
>>>>>>>> +
>>>>>>>> +	return rproc;
>>>>>>>> +}
>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>>>>>>> +
>>>>>>>> +/**
>>>>>>>> + * pru_rproc_put() - release the PRU rproc resource
>>>>>>>> + * @rproc: the rproc resource to release
>>>>>>>> + *
>>>>>>>> + * Releases the PRU rproc resource and makes it available to other
>>>>>>>> + * users.
>>>>>>>> + */
>>>>>>>> +void pru_rproc_put(struct rproc *rproc)
>>>>>>>> +{
>>>>>>>> +	struct pru_rproc *pru;
>>>>>>>> +
>>>>>>>> +	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>>>>>>> +		return;
>>>>>>>> +
>>>>>>>> +	pru = rproc->priv;
>>>>>>>> +
>>>>>>>> +	mutex_lock(&pru->lock);
>>>>>>>> +
>>>>>>>> +	if (!pru->client_np) {
>>>>>>>> +		mutex_unlock(&pru->lock);
>>>>>>>> +		return;
>>>>>>>> +	}
>>>>>>>> +
>>>>>>>> +	pru->client_np = NULL;
>>>>>>>> +	mutex_unlock(&pru->lock);
>>>>>>>> +
>>>>>>>> +	put_device(&rproc->dev);
>>>>>>>> +}
>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>>>>>>> +
>>>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>>>>>>   {
>>>>>>>>   	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>>>>>>   	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>>>>>>   	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>>>>>>   	/* PRU1 has its local RAM addresses reversed */
>>>>>>>> -	if (pru->id == 1)
>>>>>>>> +	if (pru->id == PRUSS_PRU1)
>>>>>>>>   		swap(dram0, dram1);
>>>>>>>>   	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>>>>>>   	case RTU0_IRAM_ADDR_MASK:
>>>>>>>>   		fallthrough;
>>>>>>>>   	case PRU0_IRAM_ADDR_MASK:
>>>>>>>> -		pru->id = 0;
>>>>>>>> +		pru->id = PRUSS_PRU0;
>>>>>>>>   		break;
>>>>>>>>   	case TX_PRU1_IRAM_ADDR_MASK:
>>>>>>>>   		fallthrough;
>>>>>>>>   	case RTU1_IRAM_ADDR_MASK:
>>>>>>>>   		fallthrough;
>>>>>>>>   	case PRU1_IRAM_ADDR_MASK:
>>>>>>>> -		pru->id = 1;
>>>>>>>> +		pru->id = PRUSS_PRU1;
>>>>>>>>   		break;
>>>>>>>>   	default:
>>>>>>>>   		ret = -EINVAL;
>>>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>>>>>>   	pru->pruss = platform_get_drvdata(ppdev);
>>>>>>>>   	pru->rproc = rproc;
>>>>>>>>   	pru->fw_name = fw_name;
>>>>>>>> +	pru->client_np = NULL;
>>>>>>>> +	mutex_init(&pru->lock);
>>>>>>>>   	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>>>>>>   		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>>>>>>   static struct platform_driver pru_rproc_driver = {
>>>>>>>>   	.driver = {
>>>>>>>> -		.name   = "pru-rproc",
>>>>>>>> +		.name   = PRU_RPROC_DRVNAME,
>>>>>>>>   		.of_match_table = pru_rproc_match,
>>>>>>>>   		.suppress_bind_attrs = true,
>>>>>>>>   	},
>>>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>>>>>>   MODULE_LICENSE("GPL v2");
>>>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>>>>>>> new file mode 100644
>>>>>>>> index 000000000000..fdc719b43db0
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/include/linux/pruss.h
>>>>>>>> @@ -0,0 +1,56 @@
>>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>>>>>> +/**
>>>>>>>> + * PRU-ICSS Subsystem user interfaces
>>>>>>>> + *
>>>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>>>>>>> + *	Suman Anna <[e-mail]>
>>>>>>>> + */
>>>>>>>> +
>>>>>>>> +#ifndef __LINUX_PRUSS_H
>>>>>>>> +#define __LINUX_PRUSS_H
>>>>>>>> +
>>>>>>>> +#include <linux/device.h>
>>>>>>>> +#include <linux/types.h>
>>>>>>>> +
>>>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>>>>>>> +
>>>>>>>> +/*
>>>>>>>> + * enum pruss_pru_id - PRU core identifiers
>>>>>>>> + */
>>>>>>>> +enum pruss_pru_id {
>>>>>>>> +	PRUSS_PRU0 = 0,
>>>>>>>> +	PRUSS_PRU1,
>>>>>>>> +	PRUSS_NUM_PRUS,
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct device_node;
>>>>>>>> +
>>>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>>>>>>> +
>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>>> +			    enum pruss_pru_id *pru_id);
>>>>>>>> +void pru_rproc_put(struct rproc *rproc);
>>>>>>>> +
>>>>>>>> +#else
>>>>>>>> +
>>>>>>>> +static inline struct rproc *
>>>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>>>>>>> +{
>>>>>>>> +	return ERR_PTR(-EOPNOTSUPP);
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>>>>>>> +
>>>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>>>>>>> +
>>>>>>>> +static inline bool is_pru_rproc(struct device *dev)
>>>>>>>> +{
>>>>>>>> +	const char *drv_name = dev_driver_string(dev);
>>>>>>>> +
>>>>>>>> +	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>>>>>>> +		return false;
>>>>>>>> +
>>>>>>>> +	return true;
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> +#endif /* __LINUX_PRUSS_H */
>>>>>>>> -- 
>>>>>>>> 2.17.1
>>>>>>>>
>>
>

Mathieu Poirier Sept. 19, 2022, 8:45 p.m. UTC | #9

On Tue, 13 Sept 2022 at 05:40, Md Danish Anwar <[e-mail]> wrote:
>
> Hi Mathieu,
>
> On 12/09/22 18:54, Romain Naour wrote:
> > Hi Danish, All,
> >
> > Le 07/09/2022 à 11:24, Md Danish Anwar a écrit :
> >> Hi Mathieu,
> >>
> >> On 07/09/22 00:58, Mathieu Poirier wrote:
> >>> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
> >>>> Hi Mathieu,
> >>>>
> >>>>
> >>>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
> >>>>> +Danish
> >>>>>
> >>>>> Hi Mathieu,
> >>>>>
> >>>>> On 14/07/22 22:50, Mathieu Poirier wrote:
> >>>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
> >>>>>>> Hi Puranjay,
> >>>>>
> >>>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
> >>>>>
> >>>>> Regards,
> >>>>> Kishon
> >>>>>>>
> >>>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
> >>>>>>>> From: Tero Kristo <[e-mail]>
> >>>>>>>>
> >>>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
> >>>>>>>> driver to allow client drivers to acquire and release the remoteproc
> >>>>>>>> device associated with a PRU core. The PRU cores are treated as
> >>>>>>>> resources with only one client owning it at a time.
> >>>>>>>>
> >>>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
> >>>>>>>> to a PRU core identified by the device tree "ti,prus" property under
> >>>>>>>> the client node. The pru_rproc_put() is the complementary function
> >>>>>>>> to pru_rproc_get().
> >>>>>>>>
> >>>>>>>> Co-developed-by: Suman Anna <[e-mail]>
> >>>>>>>> Signed-off-by: Suman Anna <[e-mail]>
> >>>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
> >>>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
> >>>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
> >>>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
> >>>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
> >>>>>>>> ---
> >>>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
> >>>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
> >>>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
> >>>>>>>>   create mode 100644 include/linux/pruss.h
> >>>>>>>>
> >>>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> >>>>>>>> index 1777a01fa84e..7a35b400287a 100644
> >>>>>>>> --- a/drivers/remoteproc/pru_rproc.c
> >>>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
> >>>>>>>> @@ -2,12 +2,13 @@
> >>>>>>>>   /*
> >>>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
> >>>>>>>>    *
> >>>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
> >>>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
> >>>>>>>>    *
> >>>>>>>>    * Author(s):
> >>>>>>>>    *   Suman Anna <[e-mail]>
> >>>>>>>>    *   Andrew F. Davis <[e-mail]>
> >>>>>>>>    *   Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
> >>>>>>>> + *    Puranjay Mohan <[e-mail]>
> >>>>>>>>    */
> >>>>>>>>   #include <linux/bitops.h>
> >>>>>>>> @@ -16,6 +17,7 @@
> >>>>>>>>   #include <linux/module.h>
> >>>>>>>>   #include <linux/of_device.h>
> >>>>>>>>   #include <linux/of_irq.h>
> >>>>>>>> +#include <linux/pruss.h>
> >>>>>>>>   #include <linux/pruss_driver.h>
> >>>>>>>>   #include <linux/remoteproc.h>
> >>>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
> >>>>>>>>    * @rproc: remoteproc pointer for this PRU core
> >>>>>>>>    * @data: PRU core specific data
> >>>>>>>>    * @mem_regions: data for each of the PRU memory regions
> >>>>>>>> + * @client_np: client device node
> >>>>>>>> + * @lock: mutex to protect client usage
> >>>>>>>>    * @fw_name: name of firmware image used during loading
> >>>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
> >>>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
> >>>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
> >>>>>>>>        struct rproc *rproc;
> >>>>>>>>        const struct pru_private_data *data;
> >>>>>>>>        struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
> >>>>>>>> +      struct device_node *client_np;
> >>>>>>>> +      struct mutex lock; /* client access lock */
> >>>>>>>>        const char *fw_name;
> >>>>>>>>        unsigned int *mapped_irq;
> >>>>>>>>        struct pru_irq_rsc *pru_interrupt_map;
> >>>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
> >>>>>>>>        writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
> >>>>>>>>   }
> >>>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
> >>>>>>>> +{
> >>>>>>>> +      struct device_node *rproc_np = NULL;
> >>>>>>>> +      struct platform_device *pdev;
> >>>>>>>> +      struct rproc *rproc;
> >>>>>>>> +
> >>>>>>>> +      rproc_np = of_parse_phandle(np, "ti,prus", index);
> >>>>>>>> +      if (!rproc_np || !of_device_is_available(rproc_np))
> >>>>>>>> +              return ERR_PTR(-ENODEV);
> >>>>>>>> +
> >>>>>>>> +      pdev = of_find_device_by_node(rproc_np);
> >>>>>>>> +      of_node_put(rproc_np);
> >>>>>>>> +
> >>>>>>>> +      if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
> >>>>>>>> +              /* probably PRU not yet probed */
> >>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
> >>>>>>>> +
> >>>>>>>> +      /* make sure it is PRU rproc */
> >>>>>>>> +      if (!is_pru_rproc(&pdev->dev)) {
> >>>>>>>> +              put_device(&pdev->dev);
> >>>>>>>> +              return ERR_PTR(-ENODEV);
> >>>>>>>> +      }
> >>>>>>>> +
> >>>>>>>> +      rproc = platform_get_drvdata(pdev);
> >>>>>>>> +      put_device(&pdev->dev);
> >>>>>>>> +      if (!rproc)
> >>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
> >>>>>>>> +
> >>>>>>>> +      get_device(&rproc->dev);
> >>>>>>>> +
> >>>>>>>> +      return rproc;
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>> +/**
> >>>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
> >>>>>>>> + * @np: the user/client device node
> >>>>>>>> + * @index: index to use for the ti,prus property
> >>>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
> >>>>>>>> + *
> >>>>>>>> + * This function looks through a client device node's "ti,prus" property at
> >>>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
> >>>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
> >>>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
> >>>>>>>> + * required if the function returns a failure.
> >>>>>>>> + *
> >>>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
> >>>>>>>> + * returned.
> >>>>>>>> + *
> >>>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
> >>>>>>>> + * of the following error values
> >>>>>>>> + *    -ENODEV if device is not found
> >>>>>>>> + *    -EBUSY if PRU is already acquired by anyone
> >>>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
> >>>>>>>> + */
> >>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> >>>>>>>> +                          enum pruss_pru_id *pru_id)
> >>>>>>>> +{
> >>>>>>>> +      struct rproc *rproc;
> >>>>>>>> +      struct pru_rproc *pru;
> >>>>>>>> +      struct device *dev;
> >>>>>>>> +
> >>>>>>>> +      try_module_get(THIS_MODULE);
> >>>>>>>
> >>>>>>> There should be a module_put() in pru_rproc_put()...
> >>>>>>
> >>>>>> ... and in the error path of this function.
> >>>>>>
> >>>>>>>
> >>>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
> >>>>>>> with a remote processor being removed or detached.
> >>>>>>>
> >>>>>>
> >>>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
> >>>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
> >>>>>> go away before the end of the function.
> >>>>>>
> >>>>>> More comments to come...
> >>>>
> >>>> It is possible to call rproc_get_by_handle() here instead of
> >>>> __pru_get_proc(), but that would not provide multiple functionality.
> >>>>
> >>>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
> >>>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
> >>>> multiple functionality and opportunity for us to distinguish between
> >>>> multiple errors.
> >>>>
> >>>> So we have these three options.
> >>>>
> >>>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
> >>>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
> >>>> and also all the functions that uses rproc_get_by_handle().
> >>>>
> >>>
> >>> Not optimal.
> >>>
> >>>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
> >>>> using multiple ERR_PTR on different kinds of error.
> >>>>
> >>>
> >>> Not optimal.
> >>>
> >>>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
> >>>> will make sure we have the proper ERR_PTR to retrun for different kinds of
> >>>> errors.
> >>>>
> >>>
> >>> Unacceptable for the reason I already stated.
> >>>
> >>>> Please let me know which option to continue with.
> >>>
> >>> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().
>
> We can introduce a new API __rproc_get_by_phandle() similar to the API
> rproc_get_by_phandle(). The new API __rproc_get_by_phandle() will do all the
> functionality of getting the rproc. On success it will return rproc and on
> failure it will return the different ERR_PTR.
> If rproc is not probed yet, it will return ERR_PTR(-EPROBE_DEFER).
>
> This will make sure that we're getting different error codes for different
> errors from pru_rproc_get().
>
> The old API rproc_get_by_handle() will invoke the new API. On success the new
> API will return rproc and the old API will also return rproc. On failure the
> new API will return different error codes while the old API will preserve it's
> nature and return NULL.

I meant to create a wrapper around rproc_get_by_handle() that is local
to pru_rproc.c.  That way you can enact the behavior you want without
having to constrain others in this specific design.

Thanks,
Mathieu

>
> The API __rproc_get_by_handle will look like this.
>
> struct rproc *__rproc_get_by_handle(phandle phandle)
> {
>         struct rproc *rproc = NULL, *r;
>         struct device_node *np;
>
>         np = of_find_node_by_phandle(phandle);
>         if (!np)
>                 return NULL;
>
>         rcu_read_lock();
>         list_for_each_entry_rcu(r, &rproc_list, node) {
>                 if (r->dev.parent && r->dev.parent->of_node == np) {
>                         /*prevent underlying implementation from being removed */
>                         if (!try_module_get(r->dev.parent->driver->owner)) {
>                                 dev_err(&r->dev, "can't get owner\n");
>                                 break;
>                         }
>
>                         rproc = r;
>                         get_device(&rproc->dev);
>                         break;
>                 }
>         }
>         rcu_read_unlock();
>
>         of_node_put(np);
>
>         if(!rproc)
>                 return ERR_PTR(-EPROBE_DEFER);
>
>         return rproc;
> }
>
> The API rproc_get_by_handle() will look like this.
>
> struct rproc *rproc_get_by_phandle(phandle phandle)
> {
>         struct rproc *rproc = NULL;
>
>         rproc = __rproc_get_by_handle(phandle);
>
>         if(!rproc || IS_ERR(rproc))
>                 return NULL;
>
>         return rproc;
> }
>
> This way in pru_rproc_get(), we'll get the rproc by phandle and we'll still
> return different error codes depending upon failure cases. We'll also be able
> to preserve the actual functionality of rproc_get_by_phandle() so that the
> other APIs using rproc_get_by_phandle() won't get affected.
>
> Please let me know if this looks good.
>
> >>>
> >>
> >> Sure, I'll do that. I'll share this change in v6 of this patch series.
> >
> > I'm able to test the TI prueth driver from the ti-linux-5.10.y tree [1] on a
> > AM5749 cpu (custom board). But I need a more recent kernel (at least 5.15) to
> > support other devices recently added to the Linux kernel (wifi6 module and an
> > ethernet switch). Also it would be nice if this driver is finally merged in the
> > Linux kernel.
> >
> > Maybe I can help to test this series but I noticed it only provide the driver
> > for TI AM654x cpus [2]. Can you also provide patches for basic EMAC support with
> > the TI AM574x too? (I don't need advanced features like frame timestamping, HSR
> > etc).
> >
> > Also, what about patches present in the ti-linux-kernel tree and not included
> > this this series? Especially patches that modify the kernel network stack [3]
> > (net/rpmsg: add support for new rpmsg sockets). Is this new socket protocol
> > really needed?
> >
> > Notice the patch adding the rpmsg sockets [3] already conflict with the upstream
> > kernel since the AF_MCTP definition now use the value temporarly used by
> > AF_RPMSG [4].
> >
> > Can you send an updated version of the complete series?
> >
> > Thanks!
> >
> > [1] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/log/?h=ti-linux-5.10.y
> >
> > [2] https://lore.kernel.org/linux-remoteproc/[e-mail]/
> >
> > [3]
> > https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=f4b978a978c38149f712ddd137f12ed5fb914161
> >
> > [4]
> > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc49d8169aa72295104f1558830c568efb946315
> >
> > Best regards,
> > Romain
> >
> >
> >>
> >>>>
> >>>> Thanks,
> >>>> Danish
> >>>>
> >>>>
> >>>>>>
> >>>>>>
> >>>>>>> Thanks,
> >>>>>>> Mathieu
> >>>>>>>
> >>>>>>>> +
> >>>>>>>> +      rproc = __pru_rproc_get(np, index);
> >>>>>>>> +      if (IS_ERR(rproc))
> >>>>>>>> +              return rproc;
> >>>>>>>> +
> >>>>>>>> +      pru = rproc->priv;
> >>>>>>>> +      dev = &rproc->dev;
> >>>>>>>> +
> >>>>>>>> +      mutex_lock(&pru->lock);
> >>>>>>>> +
> >>>>>>>> +      if (pru->client_np) {
> >>>>>>>> +              mutex_unlock(&pru->lock);
> >>>>>>>> +              put_device(dev);
> >>>>>>>> +              return ERR_PTR(-EBUSY);
> >>>>>>>> +      }
> >>>>>>>> +
> >>>>>>>> +      pru->client_np = np;
> >>>>>>>> +
> >>>>>>>> +      mutex_unlock(&pru->lock);
> >>>>>>>> +
> >>>>>>>> +      if (pru_id)
> >>>>>>>> +              *pru_id = pru->id;
> >>>>>>>> +
> >>>>>>>> +      return rproc;
> >>>>>>>> +}
> >>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
> >>>>>>>> +
> >>>>>>>> +/**
> >>>>>>>> + * pru_rproc_put() - release the PRU rproc resource
> >>>>>>>> + * @rproc: the rproc resource to release
> >>>>>>>> + *
> >>>>>>>> + * Releases the PRU rproc resource and makes it available to other
> >>>>>>>> + * users.
> >>>>>>>> + */
> >>>>>>>> +void pru_rproc_put(struct rproc *rproc)
> >>>>>>>> +{
> >>>>>>>> +      struct pru_rproc *pru;
> >>>>>>>> +
> >>>>>>>> +      if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
> >>>>>>>> +              return;
> >>>>>>>> +
> >>>>>>>> +      pru = rproc->priv;
> >>>>>>>> +
> >>>>>>>> +      mutex_lock(&pru->lock);
> >>>>>>>> +
> >>>>>>>> +      if (!pru->client_np) {
> >>>>>>>> +              mutex_unlock(&pru->lock);
> >>>>>>>> +              return;
> >>>>>>>> +      }
> >>>>>>>> +
> >>>>>>>> +      pru->client_np = NULL;
> >>>>>>>> +      mutex_unlock(&pru->lock);
> >>>>>>>> +
> >>>>>>>> +      put_device(&rproc->dev);
> >>>>>>>> +}
> >>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
> >>>>>>>> +
> >>>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
> >>>>>>>>   {
> >>>>>>>>        return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
> >>>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
> >>>>>>>>        dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
> >>>>>>>>        dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
> >>>>>>>>        /* PRU1 has its local RAM addresses reversed */
> >>>>>>>> -      if (pru->id == 1)
> >>>>>>>> +      if (pru->id == PRUSS_PRU1)
> >>>>>>>>                swap(dram0, dram1);
> >>>>>>>>        shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
> >>>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
> >>>>>>>>        case RTU0_IRAM_ADDR_MASK:
> >>>>>>>>                fallthrough;
> >>>>>>>>        case PRU0_IRAM_ADDR_MASK:
> >>>>>>>> -              pru->id = 0;
> >>>>>>>> +              pru->id = PRUSS_PRU0;
> >>>>>>>>                break;
> >>>>>>>>        case TX_PRU1_IRAM_ADDR_MASK:
> >>>>>>>>                fallthrough;
> >>>>>>>>        case RTU1_IRAM_ADDR_MASK:
> >>>>>>>>                fallthrough;
> >>>>>>>>        case PRU1_IRAM_ADDR_MASK:
> >>>>>>>> -              pru->id = 1;
> >>>>>>>> +              pru->id = PRUSS_PRU1;
> >>>>>>>>                break;
> >>>>>>>>        default:
> >>>>>>>>                ret = -EINVAL;
> >>>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
> >>>>>>>>        pru->pruss = platform_get_drvdata(ppdev);
> >>>>>>>>        pru->rproc = rproc;
> >>>>>>>>        pru->fw_name = fw_name;
> >>>>>>>> +      pru->client_np = NULL;
> >>>>>>>> +      mutex_init(&pru->lock);
> >>>>>>>>        for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
> >>>>>>>>                res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> >>>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
> >>>>>>>>   static struct platform_driver pru_rproc_driver = {
> >>>>>>>>        .driver = {
> >>>>>>>> -              .name   = "pru-rproc",
> >>>>>>>> +              .name   = PRU_RPROC_DRVNAME,
> >>>>>>>>                .of_match_table = pru_rproc_match,
> >>>>>>>>                .suppress_bind_attrs = true,
> >>>>>>>>        },
> >>>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
> >>>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
> >>>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
> >>>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
> >>>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
> >>>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
> >>>>>>>>   MODULE_LICENSE("GPL v2");
> >>>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
> >>>>>>>> new file mode 100644
> >>>>>>>> index 000000000000..fdc719b43db0
> >>>>>>>> --- /dev/null
> >>>>>>>> +++ b/include/linux/pruss.h
> >>>>>>>> @@ -0,0 +1,56 @@
> >>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
> >>>>>>>> +/**
> >>>>>>>> + * PRU-ICSS Subsystem user interfaces
> >>>>>>>> + *
> >>>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
> >>>>>>>> + *    Suman Anna <[e-mail]>
> >>>>>>>> + */
> >>>>>>>> +
> >>>>>>>> +#ifndef __LINUX_PRUSS_H
> >>>>>>>> +#define __LINUX_PRUSS_H
> >>>>>>>> +
> >>>>>>>> +#include <linux/device.h>
> >>>>>>>> +#include <linux/types.h>
> >>>>>>>> +
> >>>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
> >>>>>>>> +
> >>>>>>>> +/*
> >>>>>>>> + * enum pruss_pru_id - PRU core identifiers
> >>>>>>>> + */
> >>>>>>>> +enum pruss_pru_id {
> >>>>>>>> +      PRUSS_PRU0 = 0,
> >>>>>>>> +      PRUSS_PRU1,
> >>>>>>>> +      PRUSS_NUM_PRUS,
> >>>>>>>> +};
> >>>>>>>> +
> >>>>>>>> +struct device_node;
> >>>>>>>> +
> >>>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> >>>>>>>> +
> >>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> >>>>>>>> +                          enum pruss_pru_id *pru_id);
> >>>>>>>> +void pru_rproc_put(struct rproc *rproc);
> >>>>>>>> +
> >>>>>>>> +#else
> >>>>>>>> +
> >>>>>>>> +static inline struct rproc *
> >>>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
> >>>>>>>> +{
> >>>>>>>> +      return ERR_PTR(-EOPNOTSUPP);
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
> >>>>>>>> +
> >>>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
> >>>>>>>> +
> >>>>>>>> +static inline bool is_pru_rproc(struct device *dev)
> >>>>>>>> +{
> >>>>>>>> +      const char *drv_name = dev_driver_string(dev);
> >>>>>>>> +
> >>>>>>>> +      if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
> >>>>>>>> +              return false;
> >>>>>>>> +
> >>>>>>>> +      return true;
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>> +#endif /* __LINUX_PRUSS_H */
> >>>>>>>> --
> >>>>>>>> 2.17.1
> >>>>>>>>
> >>
> >

Anwar, Md Danish Sept. 26, 2022, 10:23 a.m. UTC | #10

Hi Mathieu,

On 20/09/22 02:15, Mathieu Poirier wrote:
> On Tue, 13 Sept 2022 at 05:40, Md Danish Anwar <[e-mail]> wrote:
>>
>> Hi Mathieu,
>>
>> On 12/09/22 18:54, Romain Naour wrote:
>>> Hi Danish, All,
>>>
>>> Le 07/09/2022 à 11:24, Md Danish Anwar a écrit :
>>>> Hi Mathieu,
>>>>
>>>> On 07/09/22 00:58, Mathieu Poirier wrote:
>>>>> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
>>>>>> Hi Mathieu,
>>>>>>
>>>>>>
>>>>>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
>>>>>>> +Danish
>>>>>>>
>>>>>>> Hi Mathieu,
>>>>>>>
>>>>>>> On 14/07/22 22:50, Mathieu Poirier wrote:
>>>>>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
>>>>>>>>> Hi Puranjay,
>>>>>>>
>>>>>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Kishon
>>>>>>>>>
>>>>>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
>>>>>>>>>> From: Tero Kristo <[e-mail]>
>>>>>>>>>>
>>>>>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
>>>>>>>>>> driver to allow client drivers to acquire and release the remoteproc
>>>>>>>>>> device associated with a PRU core. The PRU cores are treated as
>>>>>>>>>> resources with only one client owning it at a time.
>>>>>>>>>>
>>>>>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
>>>>>>>>>> to a PRU core identified by the device tree "ti,prus" property under
>>>>>>>>>> the client node. The pru_rproc_put() is the complementary function
>>>>>>>>>> to pru_rproc_get().
>>>>>>>>>>
>>>>>>>>>> Co-developed-by: Suman Anna <[e-mail]>
>>>>>>>>>> Signed-off-by: Suman Anna <[e-mail]>
>>>>>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
>>>>>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
>>>>>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
>>>>>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
>>>>>>>>>> ---
>>>>>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
>>>>>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
>>>>>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
>>>>>>>>>>   create mode 100644 include/linux/pruss.h
>>>>>>>>>>
>>>>>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
>>>>>>>>>> index 1777a01fa84e..7a35b400287a 100644
>>>>>>>>>> --- a/drivers/remoteproc/pru_rproc.c
>>>>>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
>>>>>>>>>> @@ -2,12 +2,13 @@
>>>>>>>>>>   /*
>>>>>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
>>>>>>>>>>    *
>>>>>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
>>>>>>>>>>    *
>>>>>>>>>>    * Author(s):
>>>>>>>>>>    *   Suman Anna <[e-mail]>
>>>>>>>>>>    *   Andrew F. Davis <[e-mail]>
>>>>>>>>>>    *   Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
>>>>>>>>>> + *    Puranjay Mohan <[e-mail]>
>>>>>>>>>>    */
>>>>>>>>>>   #include <linux/bitops.h>
>>>>>>>>>> @@ -16,6 +17,7 @@
>>>>>>>>>>   #include <linux/module.h>
>>>>>>>>>>   #include <linux/of_device.h>
>>>>>>>>>>   #include <linux/of_irq.h>
>>>>>>>>>> +#include <linux/pruss.h>
>>>>>>>>>>   #include <linux/pruss_driver.h>
>>>>>>>>>>   #include <linux/remoteproc.h>
>>>>>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
>>>>>>>>>>    * @rproc: remoteproc pointer for this PRU core
>>>>>>>>>>    * @data: PRU core specific data
>>>>>>>>>>    * @mem_regions: data for each of the PRU memory regions
>>>>>>>>>> + * @client_np: client device node
>>>>>>>>>> + * @lock: mutex to protect client usage
>>>>>>>>>>    * @fw_name: name of firmware image used during loading
>>>>>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
>>>>>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
>>>>>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
>>>>>>>>>>        struct rproc *rproc;
>>>>>>>>>>        const struct pru_private_data *data;
>>>>>>>>>>        struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
>>>>>>>>>> +      struct device_node *client_np;
>>>>>>>>>> +      struct mutex lock; /* client access lock */
>>>>>>>>>>        const char *fw_name;
>>>>>>>>>>        unsigned int *mapped_irq;
>>>>>>>>>>        struct pru_irq_rsc *pru_interrupt_map;
>>>>>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
>>>>>>>>>>        writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
>>>>>>>>>>   }
>>>>>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
>>>>>>>>>> +{
>>>>>>>>>> +      struct device_node *rproc_np = NULL;
>>>>>>>>>> +      struct platform_device *pdev;
>>>>>>>>>> +      struct rproc *rproc;
>>>>>>>>>> +
>>>>>>>>>> +      rproc_np = of_parse_phandle(np, "ti,prus", index);
>>>>>>>>>> +      if (!rproc_np || !of_device_is_available(rproc_np))
>>>>>>>>>> +              return ERR_PTR(-ENODEV);
>>>>>>>>>> +
>>>>>>>>>> +      pdev = of_find_device_by_node(rproc_np);
>>>>>>>>>> +      of_node_put(rproc_np);
>>>>>>>>>> +
>>>>>>>>>> +      if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
>>>>>>>>>> +              /* probably PRU not yet probed */
>>>>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
>>>>>>>>>> +
>>>>>>>>>> +      /* make sure it is PRU rproc */
>>>>>>>>>> +      if (!is_pru_rproc(&pdev->dev)) {
>>>>>>>>>> +              put_device(&pdev->dev);
>>>>>>>>>> +              return ERR_PTR(-ENODEV);
>>>>>>>>>> +      }
>>>>>>>>>> +
>>>>>>>>>> +      rproc = platform_get_drvdata(pdev);
>>>>>>>>>> +      put_device(&pdev->dev);
>>>>>>>>>> +      if (!rproc)
>>>>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
>>>>>>>>>> +
>>>>>>>>>> +      get_device(&rproc->dev);
>>>>>>>>>> +
>>>>>>>>>> +      return rproc;
>>>>>>>>>> +}
>>>>>>>>>> +
>>>>>>>>>> +/**
>>>>>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
>>>>>>>>>> + * @np: the user/client device node
>>>>>>>>>> + * @index: index to use for the ti,prus property
>>>>>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
>>>>>>>>>> + *
>>>>>>>>>> + * This function looks through a client device node's "ti,prus" property at
>>>>>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
>>>>>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
>>>>>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
>>>>>>>>>> + * required if the function returns a failure.
>>>>>>>>>> + *
>>>>>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
>>>>>>>>>> + * returned.
>>>>>>>>>> + *
>>>>>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
>>>>>>>>>> + * of the following error values
>>>>>>>>>> + *    -ENODEV if device is not found
>>>>>>>>>> + *    -EBUSY if PRU is already acquired by anyone
>>>>>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
>>>>>>>>>> + */
>>>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>>>>> +                          enum pruss_pru_id *pru_id)
>>>>>>>>>> +{
>>>>>>>>>> +      struct rproc *rproc;
>>>>>>>>>> +      struct pru_rproc *pru;
>>>>>>>>>> +      struct device *dev;
>>>>>>>>>> +
>>>>>>>>>> +      try_module_get(THIS_MODULE);
>>>>>>>>>
>>>>>>>>> There should be a module_put() in pru_rproc_put()...
>>>>>>>>
>>>>>>>> ... and in the error path of this function.
>>>>>>>>
>>>>>>>>>
>>>>>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
>>>>>>>>> with a remote processor being removed or detached.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
>>>>>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
>>>>>>>> go away before the end of the function.
>>>>>>>>
>>>>>>>> More comments to come...
>>>>>>
>>>>>> It is possible to call rproc_get_by_handle() here instead of
>>>>>> __pru_get_proc(), but that would not provide multiple functionality.
>>>>>>
>>>>>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
>>>>>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
>>>>>> multiple functionality and opportunity for us to distinguish between
>>>>>> multiple errors.
>>>>>>
>>>>>> So we have these three options.
>>>>>>
>>>>>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
>>>>>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
>>>>>> and also all the functions that uses rproc_get_by_handle().
>>>>>>
>>>>>
>>>>> Not optimal.
>>>>>
>>>>>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
>>>>>> using multiple ERR_PTR on different kinds of error.
>>>>>>
>>>>>
>>>>> Not optimal.
>>>>>
>>>>>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
>>>>>> will make sure we have the proper ERR_PTR to retrun for different kinds of
>>>>>> errors.
>>>>>>
>>>>>
>>>>> Unacceptable for the reason I already stated.
>>>>>
>>>>>> Please let me know which option to continue with.
>>>>>
>>>>> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().
>>
>> We can introduce a new API __rproc_get_by_phandle() similar to the API
>> rproc_get_by_phandle(). The new API __rproc_get_by_phandle() will do all the
>> functionality of getting the rproc. On success it will return rproc and on
>> failure it will return the different ERR_PTR.
>> If rproc is not probed yet, it will return ERR_PTR(-EPROBE_DEFER).
>>
>> This will make sure that we're getting different error codes for different
>> errors from pru_rproc_get().
>>
>> The old API rproc_get_by_handle() will invoke the new API. On success the new
>> API will return rproc and the old API will also return rproc. On failure the
>> new API will return different error codes while the old API will preserve it's
>> nature and return NULL.
> 
> I meant to create a wrapper around rproc_get_by_handle() that is local
> to pru_rproc.c.  That way you can enact the behavior you want without
> having to constrain others in this specific design.
> 
> Thanks,
> Mathieu
> 
As The API rproc_get_by_phandle() returns null on failure, I am not able to
create a wrapper around this API, which is local to pru_rproc.c to enact the
different behaviors that I want. As the API is only returning null on failure
but pru_rproc_get needs different error codes for different failures. We can
create a wrapper but that won't be able to provide different error codes that
we want in pru_rproc_get().

This is why I am suggesting to introduce new API [__rproc_get_by_phandle()]
similar to rproc_get_by_handle(). The new API can return different error codes
on different error. While the older API [rproc_get_by_handle()] will call the
new API and on failure on new API the older API will just return null
irrespective of the error code returned by the new API. Thus preserving it's
original design.

This way we can enact the behavior that we want by calling the new API while
the other APIs dependent on the older API, can still call
rproc_get_by_phandle() without any change to the existing design.

We can have a little discussion to discuss this further on some IRC channel or
meeting if it's possible.

Thanks,
Danish


>>
>> The API __rproc_get_by_handle will look like this.
>>
>> struct rproc *__rproc_get_by_handle(phandle phandle)
>> {
>>         struct rproc *rproc = NULL, *r;
>>         struct device_node *np;
>>
>>         np = of_find_node_by_phandle(phandle);
>>         if (!np)
>>                 return NULL;
>>
>>         rcu_read_lock();
>>         list_for_each_entry_rcu(r, &rproc_list, node) {
>>                 if (r->dev.parent && r->dev.parent->of_node == np) {
>>                         /*prevent underlying implementation from being removed */
>>                         if (!try_module_get(r->dev.parent->driver->owner)) {
>>                                 dev_err(&r->dev, "can't get owner\n");
>>                                 break;
>>                         }
>>
>>                         rproc = r;
>>                         get_device(&rproc->dev);
>>                         break;
>>                 }
>>         }
>>         rcu_read_unlock();
>>
>>         of_node_put(np);
>>
>>         if(!rproc)
>>                 return ERR_PTR(-EPROBE_DEFER);
>>
>>         return rproc;
>> }
>>
>> The API rproc_get_by_handle() will look like this.
>>
>> struct rproc *rproc_get_by_phandle(phandle phandle)
>> {
>>         struct rproc *rproc = NULL;
>>
>>         rproc = __rproc_get_by_handle(phandle);
>>
>>         if(!rproc || IS_ERR(rproc))
>>                 return NULL;
>>
>>         return rproc;
>> }
>>
>> This way in pru_rproc_get(), we'll get the rproc by phandle and we'll still
>> return different error codes depending upon failure cases. We'll also be able
>> to preserve the actual functionality of rproc_get_by_phandle() so that the
>> other APIs using rproc_get_by_phandle() won't get affected.
>>
>> Please let me know if this looks good.
>>
>>>>>
>>>>
>>>> Sure, I'll do that. I'll share this change in v6 of this patch series.
>>>
>>> I'm able to test the TI prueth driver from the ti-linux-5.10.y tree [1] on a
>>> AM5749 cpu (custom board). But I need a more recent kernel (at least 5.15) to
>>> support other devices recently added to the Linux kernel (wifi6 module and an
>>> ethernet switch). Also it would be nice if this driver is finally merged in the
>>> Linux kernel.
>>>
>>> Maybe I can help to test this series but I noticed it only provide the driver
>>> for TI AM654x cpus [2]. Can you also provide patches for basic EMAC support with
>>> the TI AM574x too? (I don't need advanced features like frame timestamping, HSR
>>> etc).
>>>
>>> Also, what about patches present in the ti-linux-kernel tree and not included
>>> this this series? Especially patches that modify the kernel network stack [3]
>>> (net/rpmsg: add support for new rpmsg sockets). Is this new socket protocol
>>> really needed?
>>>
>>> Notice the patch adding the rpmsg sockets [3] already conflict with the upstream
>>> kernel since the AF_MCTP definition now use the value temporarly used by
>>> AF_RPMSG [4].
>>>
>>> Can you send an updated version of the complete series?
>>>
>>> Thanks!
>>>
>>> [1] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/log/?h=ti-linux-5.10.y
>>>
>>> [2] https://lore.kernel.org/linux-remoteproc/[e-mail]/
>>>
>>> [3]
>>> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=f4b978a978c38149f712ddd137f12ed5fb914161
>>>
>>> [4]
>>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc49d8169aa72295104f1558830c568efb946315
>>>
>>> Best regards,
>>> Romain
>>>
>>>
>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> Danish
>>>>>>
>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Mathieu
>>>>>>>>>
>>>>>>>>>> +
>>>>>>>>>> +      rproc = __pru_rproc_get(np, index);
>>>>>>>>>> +      if (IS_ERR(rproc))
>>>>>>>>>> +              return rproc;
>>>>>>>>>> +
>>>>>>>>>> +      pru = rproc->priv;
>>>>>>>>>> +      dev = &rproc->dev;
>>>>>>>>>> +
>>>>>>>>>> +      mutex_lock(&pru->lock);
>>>>>>>>>> +
>>>>>>>>>> +      if (pru->client_np) {
>>>>>>>>>> +              mutex_unlock(&pru->lock);
>>>>>>>>>> +              put_device(dev);
>>>>>>>>>> +              return ERR_PTR(-EBUSY);
>>>>>>>>>> +      }
>>>>>>>>>> +
>>>>>>>>>> +      pru->client_np = np;
>>>>>>>>>> +
>>>>>>>>>> +      mutex_unlock(&pru->lock);
>>>>>>>>>> +
>>>>>>>>>> +      if (pru_id)
>>>>>>>>>> +              *pru_id = pru->id;
>>>>>>>>>> +
>>>>>>>>>> +      return rproc;
>>>>>>>>>> +}
>>>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
>>>>>>>>>> +
>>>>>>>>>> +/**
>>>>>>>>>> + * pru_rproc_put() - release the PRU rproc resource
>>>>>>>>>> + * @rproc: the rproc resource to release
>>>>>>>>>> + *
>>>>>>>>>> + * Releases the PRU rproc resource and makes it available to other
>>>>>>>>>> + * users.
>>>>>>>>>> + */
>>>>>>>>>> +void pru_rproc_put(struct rproc *rproc)
>>>>>>>>>> +{
>>>>>>>>>> +      struct pru_rproc *pru;
>>>>>>>>>> +
>>>>>>>>>> +      if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
>>>>>>>>>> +              return;
>>>>>>>>>> +
>>>>>>>>>> +      pru = rproc->priv;
>>>>>>>>>> +
>>>>>>>>>> +      mutex_lock(&pru->lock);
>>>>>>>>>> +
>>>>>>>>>> +      if (!pru->client_np) {
>>>>>>>>>> +              mutex_unlock(&pru->lock);
>>>>>>>>>> +              return;
>>>>>>>>>> +      }
>>>>>>>>>> +
>>>>>>>>>> +      pru->client_np = NULL;
>>>>>>>>>> +      mutex_unlock(&pru->lock);
>>>>>>>>>> +
>>>>>>>>>> +      put_device(&rproc->dev);
>>>>>>>>>> +}
>>>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
>>>>>>>>>> +
>>>>>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
>>>>>>>>>>   {
>>>>>>>>>>        return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
>>>>>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
>>>>>>>>>>        dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
>>>>>>>>>>        dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
>>>>>>>>>>        /* PRU1 has its local RAM addresses reversed */
>>>>>>>>>> -      if (pru->id == 1)
>>>>>>>>>> +      if (pru->id == PRUSS_PRU1)
>>>>>>>>>>                swap(dram0, dram1);
>>>>>>>>>>        shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
>>>>>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
>>>>>>>>>>        case RTU0_IRAM_ADDR_MASK:
>>>>>>>>>>                fallthrough;
>>>>>>>>>>        case PRU0_IRAM_ADDR_MASK:
>>>>>>>>>> -              pru->id = 0;
>>>>>>>>>> +              pru->id = PRUSS_PRU0;
>>>>>>>>>>                break;
>>>>>>>>>>        case TX_PRU1_IRAM_ADDR_MASK:
>>>>>>>>>>                fallthrough;
>>>>>>>>>>        case RTU1_IRAM_ADDR_MASK:
>>>>>>>>>>                fallthrough;
>>>>>>>>>>        case PRU1_IRAM_ADDR_MASK:
>>>>>>>>>> -              pru->id = 1;
>>>>>>>>>> +              pru->id = PRUSS_PRU1;
>>>>>>>>>>                break;
>>>>>>>>>>        default:
>>>>>>>>>>                ret = -EINVAL;
>>>>>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
>>>>>>>>>>        pru->pruss = platform_get_drvdata(ppdev);
>>>>>>>>>>        pru->rproc = rproc;
>>>>>>>>>>        pru->fw_name = fw_name;
>>>>>>>>>> +      pru->client_np = NULL;
>>>>>>>>>> +      mutex_init(&pru->lock);
>>>>>>>>>>        for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
>>>>>>>>>>                res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>>>>>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
>>>>>>>>>>   static struct platform_driver pru_rproc_driver = {
>>>>>>>>>>        .driver = {
>>>>>>>>>> -              .name   = "pru-rproc",
>>>>>>>>>> +              .name   = PRU_RPROC_DRVNAME,
>>>>>>>>>>                .of_match_table = pru_rproc_match,
>>>>>>>>>>                .suppress_bind_attrs = true,
>>>>>>>>>>        },
>>>>>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
>>>>>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
>>>>>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
>>>>>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
>>>>>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
>>>>>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
>>>>>>>>>>   MODULE_LICENSE("GPL v2");
>>>>>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
>>>>>>>>>> new file mode 100644
>>>>>>>>>> index 000000000000..fdc719b43db0
>>>>>>>>>> --- /dev/null
>>>>>>>>>> +++ b/include/linux/pruss.h
>>>>>>>>>> @@ -0,0 +1,56 @@
>>>>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>>>>>>>>> +/**
>>>>>>>>>> + * PRU-ICSS Subsystem user interfaces
>>>>>>>>>> + *
>>>>>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
>>>>>>>>>> + *    Suman Anna <[e-mail]>
>>>>>>>>>> + */
>>>>>>>>>> +
>>>>>>>>>> +#ifndef __LINUX_PRUSS_H
>>>>>>>>>> +#define __LINUX_PRUSS_H
>>>>>>>>>> +
>>>>>>>>>> +#include <linux/device.h>
>>>>>>>>>> +#include <linux/types.h>
>>>>>>>>>> +
>>>>>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
>>>>>>>>>> +
>>>>>>>>>> +/*
>>>>>>>>>> + * enum pruss_pru_id - PRU core identifiers
>>>>>>>>>> + */
>>>>>>>>>> +enum pruss_pru_id {
>>>>>>>>>> +      PRUSS_PRU0 = 0,
>>>>>>>>>> +      PRUSS_PRU1,
>>>>>>>>>> +      PRUSS_NUM_PRUS,
>>>>>>>>>> +};
>>>>>>>>>> +
>>>>>>>>>> +struct device_node;
>>>>>>>>>> +
>>>>>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
>>>>>>>>>> +
>>>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
>>>>>>>>>> +                          enum pruss_pru_id *pru_id);
>>>>>>>>>> +void pru_rproc_put(struct rproc *rproc);
>>>>>>>>>> +
>>>>>>>>>> +#else
>>>>>>>>>> +
>>>>>>>>>> +static inline struct rproc *
>>>>>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
>>>>>>>>>> +{
>>>>>>>>>> +      return ERR_PTR(-EOPNOTSUPP);
>>>>>>>>>> +}
>>>>>>>>>> +
>>>>>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
>>>>>>>>>> +
>>>>>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
>>>>>>>>>> +
>>>>>>>>>> +static inline bool is_pru_rproc(struct device *dev)
>>>>>>>>>> +{
>>>>>>>>>> +      const char *drv_name = dev_driver_string(dev);
>>>>>>>>>> +
>>>>>>>>>> +      if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
>>>>>>>>>> +              return false;
>>>>>>>>>> +
>>>>>>>>>> +      return true;
>>>>>>>>>> +}
>>>>>>>>>> +
>>>>>>>>>> +#endif /* __LINUX_PRUSS_H */
>>>>>>>>>> --
>>>>>>>>>> 2.17.1
>>>>>>>>>>
>>>>
>>>

Mathieu Poirier Sept. 29, 2022, 11:02 p.m. UTC | #11

On Mon, Sep 26, 2022 at 03:53:09PM +0530, Md Danish Anwar wrote:
> Hi Mathieu,
> 
> On 20/09/22 02:15, Mathieu Poirier wrote:
> > On Tue, 13 Sept 2022 at 05:40, Md Danish Anwar <[e-mail]> wrote:
> >>
> >> Hi Mathieu,
> >>
> >> On 12/09/22 18:54, Romain Naour wrote:
> >>> Hi Danish, All,
> >>>
> >>> Le 07/09/2022 à 11:24, Md Danish Anwar a écrit :
> >>>> Hi Mathieu,
> >>>>
> >>>> On 07/09/22 00:58, Mathieu Poirier wrote:
> >>>>> On Fri, Sep 02, 2022 at 03:09:04PM +0530, Md Danish Anwar wrote:
> >>>>>> Hi Mathieu,
> >>>>>>
> >>>>>>
> >>>>>> On 15/07/22 11:52, Kishon Vijay Abraham I wrote:
> >>>>>>> +Danish
> >>>>>>>
> >>>>>>> Hi Mathieu,
> >>>>>>>
> >>>>>>> On 14/07/22 22:50, Mathieu Poirier wrote:
> >>>>>>>> On Tue, Jul 12, 2022 at 11:59:49AM -0600, Mathieu Poirier wrote:
> >>>>>>>>> Hi Puranjay,
> >>>>>>>
> >>>>>>> Removed Puranjay (as he is no longer with TI) and adding Danish.
> >>>>>>>
> >>>>>>> Regards,
> >>>>>>> Kishon
> >>>>>>>>>
> >>>>>>>>> On Tue, Jun 07, 2022 at 10:26:46AM +0530, Puranjay Mohan wrote:
> >>>>>>>>>> From: Tero Kristo <[e-mail]>
> >>>>>>>>>>
> >>>>>>>>>> Add two new APIs, pru_rproc_get() and pru_rproc_put(), to the PRU
> >>>>>>>>>> driver to allow client drivers to acquire and release the remoteproc
> >>>>>>>>>> device associated with a PRU core. The PRU cores are treated as
> >>>>>>>>>> resources with only one client owning it at a time.
> >>>>>>>>>>
> >>>>>>>>>> The pru_rproc_get() function returns the rproc handle corresponding
> >>>>>>>>>> to a PRU core identified by the device tree "ti,prus" property under
> >>>>>>>>>> the client node. The pru_rproc_put() is the complementary function
> >>>>>>>>>> to pru_rproc_get().
> >>>>>>>>>>
> >>>>>>>>>> Co-developed-by: Suman Anna <[e-mail]>
> >>>>>>>>>> Signed-off-by: Suman Anna <[e-mail]>
> >>>>>>>>>> Signed-off-by: Tero Kristo <[e-mail]>
> >>>>>>>>>> Co-developed-by: Grzegorz Jaszczyk <[e-mail]>
> >>>>>>>>>> Signed-off-by: Grzegorz Jaszczyk <[e-mail]>
> >>>>>>>>>> Co-developed-by: Puranjay Mohan <[e-mail]>
> >>>>>>>>>> Signed-off-by: Puranjay Mohan <[e-mail]>
> >>>>>>>>>> ---
> >>>>>>>>>>   drivers/remoteproc/pru_rproc.c | 138 +++++++++++++++++++++++++++++++--
> >>>>>>>>>>   include/linux/pruss.h          |  56 +++++++++++++
> >>>>>>>>>>   2 files changed, 189 insertions(+), 5 deletions(-)
> >>>>>>>>>>   create mode 100644 include/linux/pruss.h
> >>>>>>>>>>
> >>>>>>>>>> diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
> >>>>>>>>>> index 1777a01fa84e..7a35b400287a 100644
> >>>>>>>>>> --- a/drivers/remoteproc/pru_rproc.c
> >>>>>>>>>> +++ b/drivers/remoteproc/pru_rproc.c
> >>>>>>>>>> @@ -2,12 +2,13 @@
> >>>>>>>>>>   /*
> >>>>>>>>>>    * PRU-ICSS remoteproc driver for various TI SoCs
> >>>>>>>>>>    *
> >>>>>>>>>> - * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
> >>>>>>>>>> + * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
> >>>>>>>>>>    *
> >>>>>>>>>>    * Author(s):
> >>>>>>>>>>    *   Suman Anna <[e-mail]>
> >>>>>>>>>>    *   Andrew F. Davis <[e-mail]>
> >>>>>>>>>>    *   Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
> >>>>>>>>>> + *    Puranjay Mohan <[e-mail]>
> >>>>>>>>>>    */
> >>>>>>>>>>   #include <linux/bitops.h>
> >>>>>>>>>> @@ -16,6 +17,7 @@
> >>>>>>>>>>   #include <linux/module.h>
> >>>>>>>>>>   #include <linux/of_device.h>
> >>>>>>>>>>   #include <linux/of_irq.h>
> >>>>>>>>>> +#include <linux/pruss.h>
> >>>>>>>>>>   #include <linux/pruss_driver.h>
> >>>>>>>>>>   #include <linux/remoteproc.h>
> >>>>>>>>>> @@ -111,6 +113,8 @@ struct pru_private_data {
> >>>>>>>>>>    * @rproc: remoteproc pointer for this PRU core
> >>>>>>>>>>    * @data: PRU core specific data
> >>>>>>>>>>    * @mem_regions: data for each of the PRU memory regions
> >>>>>>>>>> + * @client_np: client device node
> >>>>>>>>>> + * @lock: mutex to protect client usage
> >>>>>>>>>>    * @fw_name: name of firmware image used during loading
> >>>>>>>>>>    * @mapped_irq: virtual interrupt numbers of created fw specific mapping
> >>>>>>>>>>    * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
> >>>>>>>>>> @@ -126,6 +130,8 @@ struct pru_rproc {
> >>>>>>>>>>        struct rproc *rproc;
> >>>>>>>>>>        const struct pru_private_data *data;
> >>>>>>>>>>        struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
> >>>>>>>>>> +      struct device_node *client_np;
> >>>>>>>>>> +      struct mutex lock; /* client access lock */
> >>>>>>>>>>        const char *fw_name;
> >>>>>>>>>>        unsigned int *mapped_irq;
> >>>>>>>>>>        struct pru_irq_rsc *pru_interrupt_map;
> >>>>>>>>>> @@ -146,6 +152,125 @@ void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
> >>>>>>>>>>        writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
> >>>>>>>>>>   }
> >>>>>>>>>> +static struct rproc *__pru_rproc_get(struct device_node *np, int index)
> >>>>>>>>>> +{
> >>>>>>>>>> +      struct device_node *rproc_np = NULL;
> >>>>>>>>>> +      struct platform_device *pdev;
> >>>>>>>>>> +      struct rproc *rproc;
> >>>>>>>>>> +
> >>>>>>>>>> +      rproc_np = of_parse_phandle(np, "ti,prus", index);
> >>>>>>>>>> +      if (!rproc_np || !of_device_is_available(rproc_np))
> >>>>>>>>>> +              return ERR_PTR(-ENODEV);
> >>>>>>>>>> +
> >>>>>>>>>> +      pdev = of_find_device_by_node(rproc_np);
> >>>>>>>>>> +      of_node_put(rproc_np);
> >>>>>>>>>> +
> >>>>>>>>>> +      if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
> >>>>>>>>>> +              /* probably PRU not yet probed */
> >>>>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
> >>>>>>>>>> +
> >>>>>>>>>> +      /* make sure it is PRU rproc */
> >>>>>>>>>> +      if (!is_pru_rproc(&pdev->dev)) {
> >>>>>>>>>> +              put_device(&pdev->dev);
> >>>>>>>>>> +              return ERR_PTR(-ENODEV);
> >>>>>>>>>> +      }
> >>>>>>>>>> +
> >>>>>>>>>> +      rproc = platform_get_drvdata(pdev);
> >>>>>>>>>> +      put_device(&pdev->dev);
> >>>>>>>>>> +      if (!rproc)
> >>>>>>>>>> +              return ERR_PTR(-EPROBE_DEFER);
> >>>>>>>>>> +
> >>>>>>>>>> +      get_device(&rproc->dev);
> >>>>>>>>>> +
> >>>>>>>>>> +      return rproc;
> >>>>>>>>>> +}
> >>>>>>>>>> +
> >>>>>>>>>> +/**
> >>>>>>>>>> + * pru_rproc_get() - get the PRU rproc instance from a device node
> >>>>>>>>>> + * @np: the user/client device node
> >>>>>>>>>> + * @index: index to use for the ti,prus property
> >>>>>>>>>> + * @pru_id: optional pointer to return the PRU remoteproc processor id
> >>>>>>>>>> + *
> >>>>>>>>>> + * This function looks through a client device node's "ti,prus" property at
> >>>>>>>>>> + * index @index and returns the rproc handle for a valid PRU remote processor if
> >>>>>>>>>> + * found. The function allows only one user to own the PRU rproc resource at a
> >>>>>>>>>> + * time. Caller must call pru_rproc_put() when done with using the rproc, not
> >>>>>>>>>> + * required if the function returns a failure.
> >>>>>>>>>> + *
> >>>>>>>>>> + * When optional @pru_id pointer is passed the PRU remoteproc processor id is
> >>>>>>>>>> + * returned.
> >>>>>>>>>> + *
> >>>>>>>>>> + * Return: rproc handle on success, and an ERR_PTR on failure using one
> >>>>>>>>>> + * of the following error values
> >>>>>>>>>> + *    -ENODEV if device is not found
> >>>>>>>>>> + *    -EBUSY if PRU is already acquired by anyone
> >>>>>>>>>> + *    -EPROBE_DEFER is PRU device is not probed yet
> >>>>>>>>>> + */
> >>>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> >>>>>>>>>> +                          enum pruss_pru_id *pru_id)
> >>>>>>>>>> +{
> >>>>>>>>>> +      struct rproc *rproc;
> >>>>>>>>>> +      struct pru_rproc *pru;
> >>>>>>>>>> +      struct device *dev;
> >>>>>>>>>> +
> >>>>>>>>>> +      try_module_get(THIS_MODULE);
> >>>>>>>>>
> >>>>>>>>> There should be a module_put() in pru_rproc_put()...
> >>>>>>>>
> >>>>>>>> ... and in the error path of this function.
> >>>>>>>>
> >>>>>>>>>
> >>>>>>>>> More comments to come tomorrow.  I'm especially worried about this API racing
> >>>>>>>>> with a remote processor being removed or detached.
> >>>>>>>>>
> >>>>>>>>
> >>>>>>>> Looking at what is done in wkup_m3_ipc_probe(), it should be possible to call
> >>>>>>>> rproc_get_by_handle() here and that would make sure the remote processor doesn't
> >>>>>>>> go away before the end of the function.
> >>>>>>>>
> >>>>>>>> More comments to come...
> >>>>>>
> >>>>>> It is possible to call rproc_get_by_handle() here instead of
> >>>>>> __pru_get_proc(), but that would not provide multiple functionality.
> >>>>>>
> >>>>>> The API rproc_get_by_handle() returns rproc handle on success, and NULL on
> >>>>>> failure where as __pru_get_proc() returns ERR_PTR on failure which provides
> >>>>>> multiple functionality and opportunity for us to distinguish between
> >>>>>> multiple errors.
> >>>>>>
> >>>>>> So we have these three options.
> >>>>>>
> >>>>>> 1. If we're using the API rproc_get_by_handle() and we want the multiple
> >>>>>> ERR_PTR on failure then we will need to change the API rproc_get_by_handle()
> >>>>>> and also all the functions that uses rproc_get_by_handle().
> >>>>>>
> >>>>>
> >>>>> Not optimal.
> >>>>>
> >>>>>> 2. Keep the API rproc_get_by_handle() as it is. That will restrict us from
> >>>>>> using multiple ERR_PTR on different kinds of error.
> >>>>>>
> >>>>>
> >>>>> Not optimal.
> >>>>>
> >>>>>> 3. Instead of using rproc_get_by_handle(), keep using __pru_get_proc(). This
> >>>>>> will make sure we have the proper ERR_PTR to retrun for different kinds of
> >>>>>> errors.
> >>>>>>
> >>>>>
> >>>>> Unacceptable for the reason I already stated.
> >>>>>
> >>>>>> Please let me know which option to continue with.
> >>>>>
> >>>>> I suggest building a wrapper that does everything you want around rproc_get_by_phandle().
> >>
> >> We can introduce a new API __rproc_get_by_phandle() similar to the API
> >> rproc_get_by_phandle(). The new API __rproc_get_by_phandle() will do all the
> >> functionality of getting the rproc. On success it will return rproc and on
> >> failure it will return the different ERR_PTR.
> >> If rproc is not probed yet, it will return ERR_PTR(-EPROBE_DEFER).
> >>
> >> This will make sure that we're getting different error codes for different
> >> errors from pru_rproc_get().
> >>
> >> The old API rproc_get_by_handle() will invoke the new API. On success the new
> >> API will return rproc and the old API will also return rproc. On failure the
> >> new API will return different error codes while the old API will preserve it's
> >> nature and return NULL.
> > 
> > I meant to create a wrapper around rproc_get_by_handle() that is local
> > to pru_rproc.c.  That way you can enact the behavior you want without
> > having to constrain others in this specific design.
> > 
> > Thanks,
> > Mathieu
> > 
> As The API rproc_get_by_phandle() returns null on failure, I am not able to
> create a wrapper around this API, which is local to pru_rproc.c to enact the
> different behaviors that I want. As the API is only returning null on failure
> but pru_rproc_get needs different error codes for different failures. We can
> create a wrapper but that won't be able to provide different error codes that
> we want in pru_rproc_get().

I took a closer look at __pru_rproc_get()...

Calling of_property_read_u32_index() instead of of_parse_phandle() should do the
primary sanetary check.  After that call rproc_get_by_phandle() and return
EPROBE_DEFER if it returns NULL.  If not then you have an rproc with a platform
device that you can check with is_pru_rproc() and return whatever error code you
want if it isn't to your liking.  

> 
> This is why I am suggesting to introduce new API [__rproc_get_by_phandle()]
> similar to rproc_get_by_handle(). The new API can return different error codes
> on different error. While the older API [rproc_get_by_handle()] will call the
> new API and on failure on new API the older API will just return null
> irrespective of the error code returned by the new API. Thus preserving it's
> original design.
> 
> This way we can enact the behavior that we want by calling the new API while
> the other APIs dependent on the older API, can still call
> rproc_get_by_phandle() without any change to the existing design.
> 
> We can have a little discussion to discuss this further on some IRC channel or
> meeting if it's possible.
> 
> Thanks,
> Danish
> 
> 
> >>
> >> The API __rproc_get_by_handle will look like this.
> >>
> >> struct rproc *__rproc_get_by_handle(phandle phandle)
> >> {
> >>         struct rproc *rproc = NULL, *r;
> >>         struct device_node *np;
> >>
> >>         np = of_find_node_by_phandle(phandle);
> >>         if (!np)
> >>                 return NULL;
> >>
> >>         rcu_read_lock();
> >>         list_for_each_entry_rcu(r, &rproc_list, node) {
> >>                 if (r->dev.parent && r->dev.parent->of_node == np) {
> >>                         /*prevent underlying implementation from being removed */
> >>                         if (!try_module_get(r->dev.parent->driver->owner)) {
> >>                                 dev_err(&r->dev, "can't get owner\n");
> >>                                 break;
> >>                         }
> >>
> >>                         rproc = r;
> >>                         get_device(&rproc->dev);
> >>                         break;
> >>                 }
> >>         }
> >>         rcu_read_unlock();
> >>
> >>         of_node_put(np);
> >>
> >>         if(!rproc)
> >>                 return ERR_PTR(-EPROBE_DEFER);
> >>
> >>         return rproc;
> >> }
> >>
> >> The API rproc_get_by_handle() will look like this.
> >>
> >> struct rproc *rproc_get_by_phandle(phandle phandle)
> >> {
> >>         struct rproc *rproc = NULL;
> >>
> >>         rproc = __rproc_get_by_handle(phandle);
> >>
> >>         if(!rproc || IS_ERR(rproc))
> >>                 return NULL;
> >>
> >>         return rproc;
> >> }
> >>
> >> This way in pru_rproc_get(), we'll get the rproc by phandle and we'll still
> >> return different error codes depending upon failure cases. We'll also be able
> >> to preserve the actual functionality of rproc_get_by_phandle() so that the
> >> other APIs using rproc_get_by_phandle() won't get affected.
> >>
> >> Please let me know if this looks good.
> >>
> >>>>>
> >>>>
> >>>> Sure, I'll do that. I'll share this change in v6 of this patch series.
> >>>
> >>> I'm able to test the TI prueth driver from the ti-linux-5.10.y tree [1] on a
> >>> AM5749 cpu (custom board). But I need a more recent kernel (at least 5.15) to
> >>> support other devices recently added to the Linux kernel (wifi6 module and an
> >>> ethernet switch). Also it would be nice if this driver is finally merged in the
> >>> Linux kernel.
> >>>
> >>> Maybe I can help to test this series but I noticed it only provide the driver
> >>> for TI AM654x cpus [2]. Can you also provide patches for basic EMAC support with
> >>> the TI AM574x too? (I don't need advanced features like frame timestamping, HSR
> >>> etc).
> >>>
> >>> Also, what about patches present in the ti-linux-kernel tree and not included
> >>> this this series? Especially patches that modify the kernel network stack [3]
> >>> (net/rpmsg: add support for new rpmsg sockets). Is this new socket protocol
> >>> really needed?
> >>>
> >>> Notice the patch adding the rpmsg sockets [3] already conflict with the upstream
> >>> kernel since the AF_MCTP definition now use the value temporarly used by
> >>> AF_RPMSG [4].
> >>>
> >>> Can you send an updated version of the complete series?
> >>>
> >>> Thanks!
> >>>
> >>> [1] https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/log/?h=ti-linux-5.10.y
> >>>
> >>> [2] https://lore.kernel.org/linux-remoteproc/[e-mail]/
> >>>
> >>> [3]
> >>> https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/commit/?h=ti-linux-5.10.y&id=f4b978a978c38149f712ddd137f12ed5fb914161
> >>>
> >>> [4]
> >>> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bc49d8169aa72295104f1558830c568efb946315
> >>>
> >>> Best regards,
> >>> Romain
> >>>
> >>>
> >>>>
> >>>>>>
> >>>>>> Thanks,
> >>>>>> Danish
> >>>>>>
> >>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>> Thanks,
> >>>>>>>>> Mathieu
> >>>>>>>>>
> >>>>>>>>>> +
> >>>>>>>>>> +      rproc = __pru_rproc_get(np, index);
> >>>>>>>>>> +      if (IS_ERR(rproc))
> >>>>>>>>>> +              return rproc;
> >>>>>>>>>> +
> >>>>>>>>>> +      pru = rproc->priv;
> >>>>>>>>>> +      dev = &rproc->dev;
> >>>>>>>>>> +
> >>>>>>>>>> +      mutex_lock(&pru->lock);
> >>>>>>>>>> +
> >>>>>>>>>> +      if (pru->client_np) {
> >>>>>>>>>> +              mutex_unlock(&pru->lock);
> >>>>>>>>>> +              put_device(dev);
> >>>>>>>>>> +              return ERR_PTR(-EBUSY);
> >>>>>>>>>> +      }
> >>>>>>>>>> +
> >>>>>>>>>> +      pru->client_np = np;
> >>>>>>>>>> +
> >>>>>>>>>> +      mutex_unlock(&pru->lock);
> >>>>>>>>>> +
> >>>>>>>>>> +      if (pru_id)
> >>>>>>>>>> +              *pru_id = pru->id;
> >>>>>>>>>> +
> >>>>>>>>>> +      return rproc;
> >>>>>>>>>> +}
> >>>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_get);
> >>>>>>>>>> +
> >>>>>>>>>> +/**
> >>>>>>>>>> + * pru_rproc_put() - release the PRU rproc resource
> >>>>>>>>>> + * @rproc: the rproc resource to release
> >>>>>>>>>> + *
> >>>>>>>>>> + * Releases the PRU rproc resource and makes it available to other
> >>>>>>>>>> + * users.
> >>>>>>>>>> + */
> >>>>>>>>>> +void pru_rproc_put(struct rproc *rproc)
> >>>>>>>>>> +{
> >>>>>>>>>> +      struct pru_rproc *pru;
> >>>>>>>>>> +
> >>>>>>>>>> +      if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
> >>>>>>>>>> +              return;
> >>>>>>>>>> +
> >>>>>>>>>> +      pru = rproc->priv;
> >>>>>>>>>> +
> >>>>>>>>>> +      mutex_lock(&pru->lock);
> >>>>>>>>>> +
> >>>>>>>>>> +      if (!pru->client_np) {
> >>>>>>>>>> +              mutex_unlock(&pru->lock);
> >>>>>>>>>> +              return;
> >>>>>>>>>> +      }
> >>>>>>>>>> +
> >>>>>>>>>> +      pru->client_np = NULL;
> >>>>>>>>>> +      mutex_unlock(&pru->lock);
> >>>>>>>>>> +
> >>>>>>>>>> +      put_device(&rproc->dev);
> >>>>>>>>>> +}
> >>>>>>>>>> +EXPORT_SYMBOL_GPL(pru_rproc_put);
> >>>>>>>>>> +
> >>>>>>>>>>   static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
> >>>>>>>>>>   {
> >>>>>>>>>>        return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
> >>>>>>>>>> @@ -438,7 +563,7 @@ static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
> >>>>>>>>>>        dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
> >>>>>>>>>>        dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
> >>>>>>>>>>        /* PRU1 has its local RAM addresses reversed */
> >>>>>>>>>> -      if (pru->id == 1)
> >>>>>>>>>> +      if (pru->id == PRUSS_PRU1)
> >>>>>>>>>>                swap(dram0, dram1);
> >>>>>>>>>>        shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
> >>>>>>>>>> @@ -747,14 +872,14 @@ static int pru_rproc_set_id(struct pru_rproc *pru)
> >>>>>>>>>>        case RTU0_IRAM_ADDR_MASK:
> >>>>>>>>>>                fallthrough;
> >>>>>>>>>>        case PRU0_IRAM_ADDR_MASK:
> >>>>>>>>>> -              pru->id = 0;
> >>>>>>>>>> +              pru->id = PRUSS_PRU0;
> >>>>>>>>>>                break;
> >>>>>>>>>>        case TX_PRU1_IRAM_ADDR_MASK:
> >>>>>>>>>>                fallthrough;
> >>>>>>>>>>        case RTU1_IRAM_ADDR_MASK:
> >>>>>>>>>>                fallthrough;
> >>>>>>>>>>        case PRU1_IRAM_ADDR_MASK:
> >>>>>>>>>> -              pru->id = 1;
> >>>>>>>>>> +              pru->id = PRUSS_PRU1;
> >>>>>>>>>>                break;
> >>>>>>>>>>        default:
> >>>>>>>>>>                ret = -EINVAL;
> >>>>>>>>>> @@ -816,6 +941,8 @@ static int pru_rproc_probe(struct platform_device *pdev)
> >>>>>>>>>>        pru->pruss = platform_get_drvdata(ppdev);
> >>>>>>>>>>        pru->rproc = rproc;
> >>>>>>>>>>        pru->fw_name = fw_name;
> >>>>>>>>>> +      pru->client_np = NULL;
> >>>>>>>>>> +      mutex_init(&pru->lock);
> >>>>>>>>>>        for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
> >>>>>>>>>>                res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> >>>>>>>>>> @@ -903,7 +1030,7 @@ MODULE_DEVICE_TABLE(of, pru_rproc_match);
> >>>>>>>>>>   static struct platform_driver pru_rproc_driver = {
> >>>>>>>>>>        .driver = {
> >>>>>>>>>> -              .name   = "pru-rproc",
> >>>>>>>>>> +              .name   = PRU_RPROC_DRVNAME,
> >>>>>>>>>>                .of_match_table = pru_rproc_match,
> >>>>>>>>>>                .suppress_bind_attrs = true,
> >>>>>>>>>>        },
> >>>>>>>>>> @@ -915,5 +1042,6 @@ module_platform_driver(pru_rproc_driver);
> >>>>>>>>>>   MODULE_AUTHOR("Suman Anna <[e-mail]>");
> >>>>>>>>>>   MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
> >>>>>>>>>>   MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
> >>>>>>>>>> +MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
> >>>>>>>>>>   MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
> >>>>>>>>>>   MODULE_LICENSE("GPL v2");
> >>>>>>>>>> diff --git a/include/linux/pruss.h b/include/linux/pruss.h
> >>>>>>>>>> new file mode 100644
> >>>>>>>>>> index 000000000000..fdc719b43db0
> >>>>>>>>>> --- /dev/null
> >>>>>>>>>> +++ b/include/linux/pruss.h
> >>>>>>>>>> @@ -0,0 +1,56 @@
> >>>>>>>>>> +/* SPDX-License-Identifier: GPL-2.0-only */
> >>>>>>>>>> +/**
> >>>>>>>>>> + * PRU-ICSS Subsystem user interfaces
> >>>>>>>>>> + *
> >>>>>>>>>> + * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
> >>>>>>>>>> + *    Suman Anna <[e-mail]>
> >>>>>>>>>> + */
> >>>>>>>>>> +
> >>>>>>>>>> +#ifndef __LINUX_PRUSS_H
> >>>>>>>>>> +#define __LINUX_PRUSS_H
> >>>>>>>>>> +
> >>>>>>>>>> +#include <linux/device.h>
> >>>>>>>>>> +#include <linux/types.h>
> >>>>>>>>>> +
> >>>>>>>>>> +#define PRU_RPROC_DRVNAME "pru-rproc"
> >>>>>>>>>> +
> >>>>>>>>>> +/*
> >>>>>>>>>> + * enum pruss_pru_id - PRU core identifiers
> >>>>>>>>>> + */
> >>>>>>>>>> +enum pruss_pru_id {
> >>>>>>>>>> +      PRUSS_PRU0 = 0,
> >>>>>>>>>> +      PRUSS_PRU1,
> >>>>>>>>>> +      PRUSS_NUM_PRUS,
> >>>>>>>>>> +};
> >>>>>>>>>> +
> >>>>>>>>>> +struct device_node;
> >>>>>>>>>> +
> >>>>>>>>>> +#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
> >>>>>>>>>> +
> >>>>>>>>>> +struct rproc *pru_rproc_get(struct device_node *np, int index,
> >>>>>>>>>> +                          enum pruss_pru_id *pru_id);
> >>>>>>>>>> +void pru_rproc_put(struct rproc *rproc);
> >>>>>>>>>> +
> >>>>>>>>>> +#else
> >>>>>>>>>> +
> >>>>>>>>>> +static inline struct rproc *
> >>>>>>>>>> +pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
> >>>>>>>>>> +{
> >>>>>>>>>> +      return ERR_PTR(-EOPNOTSUPP);
> >>>>>>>>>> +}
> >>>>>>>>>> +
> >>>>>>>>>> +static inline void pru_rproc_put(struct rproc *rproc) { }
> >>>>>>>>>> +
> >>>>>>>>>> +#endif /* CONFIG_PRU_REMOTEPROC */
> >>>>>>>>>> +
> >>>>>>>>>> +static inline bool is_pru_rproc(struct device *dev)
> >>>>>>>>>> +{
> >>>>>>>>>> +      const char *drv_name = dev_driver_string(dev);
> >>>>>>>>>> +
> >>>>>>>>>> +      if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
> >>>>>>>>>> +              return false;
> >>>>>>>>>> +
> >>>>>>>>>> +      return true;
> >>>>>>>>>> +}
> >>>>>>>>>> +
> >>>>>>>>>> +#endif /* __LINUX_PRUSS_H */
> >>>>>>>>>> --
> >>>>>>>>>> 2.17.1
> >>>>>>>>>>
> >>>>
> >>>

Patch

diff --git a/drivers/remoteproc/pru_rproc.c b/drivers/remoteproc/pru_rproc.c
index 1777a01fa84e..7a35b400287a 100644
--- a/drivers/remoteproc/pru_rproc.c
+++ b/drivers/remoteproc/pru_rproc.c
@@ -2,12 +2,13 @@ 
 /*
  * PRU-ICSS remoteproc driver for various TI SoCs
  *
- * Copyright (C) 2014-2020 Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C) 2014-2022 Texas Instruments Incorporated - https://www.ti.com/
  *
  * Author(s):
  *	Suman Anna <[e-mail]>
  *	Andrew F. Davis <[e-mail]>
  *	Grzegorz Jaszczyk <[e-mail]> for Texas Instruments
+ *	Puranjay Mohan <[e-mail]>
  */
 
 #include <linux/bitops.h>
@@ -16,6 +17,7 @@ 
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
+#include <linux/pruss.h>
 #include <linux/pruss_driver.h>
 #include <linux/remoteproc.h>
 
@@ -111,6 +113,8 @@  struct pru_private_data {
  * @rproc: remoteproc pointer for this PRU core
  * @data: PRU core specific data
  * @mem_regions: data for each of the PRU memory regions
+ * @client_np: client device node
+ * @lock: mutex to protect client usage
  * @fw_name: name of firmware image used during loading
  * @mapped_irq: virtual interrupt numbers of created fw specific mapping
  * @pru_interrupt_map: pointer to interrupt mapping description (firmware)
@@ -126,6 +130,8 @@  struct pru_rproc {
 	struct rproc *rproc;
 	const struct pru_private_data *data;
 	struct pruss_mem_region mem_regions[PRU_IOMEM_MAX];
+	struct device_node *client_np;
+	struct mutex lock; /* client access lock */
 	const char *fw_name;
 	unsigned int *mapped_irq;
 	struct pru_irq_rsc *pru_interrupt_map;
@@ -146,6 +152,125 @@  void pru_control_write_reg(struct pru_rproc *pru, unsigned int reg, u32 val)
 	writel_relaxed(val, pru->mem_regions[PRU_IOMEM_CTRL].va + reg);
 }
 
+static struct rproc *__pru_rproc_get(struct device_node *np, int index)
+{
+	struct device_node *rproc_np = NULL;
+	struct platform_device *pdev;
+	struct rproc *rproc;
+
+	rproc_np = of_parse_phandle(np, "ti,prus", index);
+	if (!rproc_np || !of_device_is_available(rproc_np))
+		return ERR_PTR(-ENODEV);
+
+	pdev = of_find_device_by_node(rproc_np);
+	of_node_put(rproc_np);
+
+	if (!pdev || !(&pdev->dev) || !((&pdev->dev)->driver))
+		/* probably PRU not yet probed */
+		return ERR_PTR(-EPROBE_DEFER);
+
+	/* make sure it is PRU rproc */
+	if (!is_pru_rproc(&pdev->dev)) {
+		put_device(&pdev->dev);
+		return ERR_PTR(-ENODEV);
+	}
+
+	rproc = platform_get_drvdata(pdev);
+	put_device(&pdev->dev);
+	if (!rproc)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	get_device(&rproc->dev);
+
+	return rproc;
+}
+
+/**
+ * pru_rproc_get() - get the PRU rproc instance from a device node
+ * @np: the user/client device node
+ * @index: index to use for the ti,prus property
+ * @pru_id: optional pointer to return the PRU remoteproc processor id
+ *
+ * This function looks through a client device node's "ti,prus" property at
+ * index @index and returns the rproc handle for a valid PRU remote processor if
+ * found. The function allows only one user to own the PRU rproc resource at a
+ * time. Caller must call pru_rproc_put() when done with using the rproc, not
+ * required if the function returns a failure.
+ *
+ * When optional @pru_id pointer is passed the PRU remoteproc processor id is
+ * returned.
+ *
+ * Return: rproc handle on success, and an ERR_PTR on failure using one
+ * of the following error values
+ *    -ENODEV if device is not found
+ *    -EBUSY if PRU is already acquired by anyone
+ *    -EPROBE_DEFER is PRU device is not probed yet
+ */
+struct rproc *pru_rproc_get(struct device_node *np, int index,
+			    enum pruss_pru_id *pru_id)
+{
+	struct rproc *rproc;
+	struct pru_rproc *pru;
+	struct device *dev;
+
+	try_module_get(THIS_MODULE);
+
+	rproc = __pru_rproc_get(np, index);
+	if (IS_ERR(rproc))
+		return rproc;
+
+	pru = rproc->priv;
+	dev = &rproc->dev;
+
+	mutex_lock(&pru->lock);
+
+	if (pru->client_np) {
+		mutex_unlock(&pru->lock);
+		put_device(dev);
+		return ERR_PTR(-EBUSY);
+	}
+
+	pru->client_np = np;
+
+	mutex_unlock(&pru->lock);
+
+	if (pru_id)
+		*pru_id = pru->id;
+
+	return rproc;
+}
+EXPORT_SYMBOL_GPL(pru_rproc_get);
+
+/**
+ * pru_rproc_put() - release the PRU rproc resource
+ * @rproc: the rproc resource to release
+ *
+ * Releases the PRU rproc resource and makes it available to other
+ * users.
+ */
+void pru_rproc_put(struct rproc *rproc)
+{
+	struct pru_rproc *pru;
+
+	if (IS_ERR_OR_NULL(rproc) || !is_pru_rproc(rproc->dev.parent))
+		return;
+
+	pru = rproc->priv;
+
+	mutex_lock(&pru->lock);
+
+	if (!pru->client_np) {
+		mutex_unlock(&pru->lock);
+		return;
+	}
+
+	pru->client_np = NULL;
+	mutex_unlock(&pru->lock);
+
+	put_device(&rproc->dev);
+}
+EXPORT_SYMBOL_GPL(pru_rproc_put);
+
 static inline u32 pru_debug_read_reg(struct pru_rproc *pru, unsigned int reg)
 {
 	return readl_relaxed(pru->mem_regions[PRU_IOMEM_DEBUG].va + reg);
@@ -438,7 +563,7 @@  static void *pru_d_da_to_va(struct pru_rproc *pru, u32 da, size_t len)
 	dram0 = pruss->mem_regions[PRUSS_MEM_DRAM0];
 	dram1 = pruss->mem_regions[PRUSS_MEM_DRAM1];
 	/* PRU1 has its local RAM addresses reversed */
-	if (pru->id == 1)
+	if (pru->id == PRUSS_PRU1)
 		swap(dram0, dram1);
 	shrd_ram = pruss->mem_regions[PRUSS_MEM_SHRD_RAM2];
 
@@ -747,14 +872,14 @@  static int pru_rproc_set_id(struct pru_rproc *pru)
 	case RTU0_IRAM_ADDR_MASK:
 		fallthrough;
 	case PRU0_IRAM_ADDR_MASK:
-		pru->id = 0;
+		pru->id = PRUSS_PRU0;
 		break;
 	case TX_PRU1_IRAM_ADDR_MASK:
 		fallthrough;
 	case RTU1_IRAM_ADDR_MASK:
 		fallthrough;
 	case PRU1_IRAM_ADDR_MASK:
-		pru->id = 1;
+		pru->id = PRUSS_PRU1;
 		break;
 	default:
 		ret = -EINVAL;
@@ -816,6 +941,8 @@  static int pru_rproc_probe(struct platform_device *pdev)
 	pru->pruss = platform_get_drvdata(ppdev);
 	pru->rproc = rproc;
 	pru->fw_name = fw_name;
+	pru->client_np = NULL;
+	mutex_init(&pru->lock);
 
 	for (i = 0; i < ARRAY_SIZE(mem_names); i++) {
 		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
@@ -903,7 +1030,7 @@  MODULE_DEVICE_TABLE(of, pru_rproc_match);
 
 static struct platform_driver pru_rproc_driver = {
 	.driver = {
-		.name   = "pru-rproc",
+		.name   = PRU_RPROC_DRVNAME,
 		.of_match_table = pru_rproc_match,
 		.suppress_bind_attrs = true,
 	},
@@ -915,5 +1042,6 @@  module_platform_driver(pru_rproc_driver);
 MODULE_AUTHOR("Suman Anna <[e-mail]>");
 MODULE_AUTHOR("Andrew F. Davis <[e-mail]>");
 MODULE_AUTHOR("Grzegorz Jaszczyk <[e-mail]>");
+MODULE_AUTHOR("Puranjay Mohan <[e-mail]>");
 MODULE_DESCRIPTION("PRU-ICSS Remote Processor Driver");
 MODULE_LICENSE("GPL v2");
diff --git a/include/linux/pruss.h b/include/linux/pruss.h
new file mode 100644
index 000000000000..fdc719b43db0
--- /dev/null
+++ b/include/linux/pruss.h
@@ -0,0 +1,56 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/**
+ * PRU-ICSS Subsystem user interfaces
+ *
+ * Copyright (C) 2015-2022 Texas Instruments Incorporated - http://www.ti.com
+ *	Suman Anna <[e-mail]>
+ */
+
+#ifndef __LINUX_PRUSS_H
+#define __LINUX_PRUSS_H
+
+#include <linux/device.h>
+#include <linux/types.h>
+
+#define PRU_RPROC_DRVNAME "pru-rproc"
+
+/*
+ * enum pruss_pru_id - PRU core identifiers
+ */
+enum pruss_pru_id {
+	PRUSS_PRU0 = 0,
+	PRUSS_PRU1,
+	PRUSS_NUM_PRUS,
+};
+
+struct device_node;
+
+#if IS_ENABLED(CONFIG_PRU_REMOTEPROC)
+
+struct rproc *pru_rproc_get(struct device_node *np, int index,
+			    enum pruss_pru_id *pru_id);
+void pru_rproc_put(struct rproc *rproc);
+
+#else
+
+static inline struct rproc *
+pru_rproc_get(struct device_node *np, int index, enum pruss_pru_id *pru_id)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
+static inline void pru_rproc_put(struct rproc *rproc) { }
+
+#endif /* CONFIG_PRU_REMOTEPROC */
+
+static inline bool is_pru_rproc(struct device *dev)
+{
+	const char *drv_name = dev_driver_string(dev);
+
+	if (strncmp(drv_name, PRU_RPROC_DRVNAME, sizeof(PRU_RPROC_DRVNAME)))
+		return false;
+
+	return true;
+}
+
+#endif /* __LINUX_PRUSS_H */