[v9,5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Commit Message

Gabriele Paoloni May 25, 2017, 11:37 a.m. UTC

From: Gabriele <[e-mail]>

On some platforms(such as Hip06/Hip07), the legacy ISA/LPC devices access
I/O with some special host-local I/O ports known on x86. As their I/O
space are not memory mapped like PCI/PCIE MMIO host bridges, this patch is
meant to support a new class of I/O host controllers where the local IO
ports of the children devices are translated into the Indirect I/O address
space.
Through the handler attach callback, all the I/O translations are done
before starting the enumeration on children devices and the translated
addresses are replaced in the children resources.

Signed-off-by: zhichang.yuan <[e-mail]>
Signed-off-by: Gabriele Paoloni <[e-mail]>
---
 drivers/acpi/arm64/Makefile            |   1 +
 drivers/acpi/arm64/acpi_indirect_pio.c | 301 +++++++++++++++++++++++++++++++++
 drivers/acpi/internal.h                |   5 +
 drivers/acpi/scan.c                    |   1 +
 include/acpi/acpi_indirect_pio.h       |  24 +++
 5 files changed, 332 insertions(+)
 create mode 100644 drivers/acpi/arm64/acpi_indirect_pio.c
 create mode 100644 include/acpi/acpi_indirect_pio.h

Comments

kernel test robot May 26, 2017, 12:03 a.m. UTC | #1

Hi Gabriele,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.12-rc2 next-20170525]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Gabriele-Paoloni/LPC-legacy-ISA-I-O-support/20170526-033719
config: ia64-allmodconfig (attached as .config)
compiler: ia64-linux-gcc (GCC) 6.2.0
reproduce:
        wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=ia64 

All errors (new ones prefixed by >>):

   drivers/built-in.o: In function `acpi_scan_init':
>> (.init.text+0x6742): undefined reference to `acpi_indirectio_scan_init'

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Lorenzo Pieralisi May 30, 2017, 1:24 p.m. UTC | #2

Hi Gab,

On Thu, May 25, 2017 at 12:37:26PM +0100, Gabriele Paoloni wrote:
> From: Gabriele <[e-mail]>
> 
> On some platforms(such as Hip06/Hip07), the legacy ISA/LPC devices access
> I/O with some special host-local I/O ports known on x86. As their I/O
> space are not memory mapped like PCI/PCIE MMIO host bridges, this patch is
> meant to support a new class of I/O host controllers where the local IO
> ports of the children devices are translated into the Indirect I/O address
> space.
> Through the handler attach callback, all the I/O translations are done
> before starting the enumeration on children devices and the translated
> addresses are replaced in the children resources.

I do not understand why this is done through a scan handler and to
be frank I do not see how this mechanism is supposed to be a generic
kernel layer, possibly used by other platforms, when there is no notion
in ACPI to cater for that.

As far as I am concerned this patch code should live in the Hisilicon
LPC driver - as things stand it is neither ACPI generic code nor ARM64
specific, it is code to make ACPI work like DT bindings without any ACPI
binding at all; I still have some concerns from an ACPI standpoint
below.

> Signed-off-by: zhichang.yuan <[e-mail]>
> Signed-off-by: Gabriele Paoloni <[e-mail]>
> ---
>  drivers/acpi/arm64/Makefile            |   1 +
>  drivers/acpi/arm64/acpi_indirect_pio.c | 301 +++++++++++++++++++++++++++++++++
>  drivers/acpi/internal.h                |   5 +
>  drivers/acpi/scan.c                    |   1 +
>  include/acpi/acpi_indirect_pio.h       |  24 +++
>  5 files changed, 332 insertions(+)
>  create mode 100644 drivers/acpi/arm64/acpi_indirect_pio.c
>  create mode 100644 include/acpi/acpi_indirect_pio.h
> 
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> index 1017def..3944775 100644
> --- a/drivers/acpi/arm64/Makefile
> +++ b/drivers/acpi/arm64/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_ACPI_IORT) 	+= iort.o
>  obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
> +obj-$(CONFIG_INDIRECT_PIO) += acpi_indirect_pio.o
> diff --git a/drivers/acpi/arm64/acpi_indirect_pio.c b/drivers/acpi/arm64/acpi_indirect_pio.c
> new file mode 100644
> index 0000000..7813f73
> --- /dev/null
> +++ b/drivers/acpi/arm64/acpi_indirect_pio.c
> @@ -0,0 +1,301 @@
> +/*
> + * ACPI support for indirect-PIO bus.
> + *
> + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> + * Author: Gabriele Paoloni <[e-mail]>
> + * Author: Zhichang Yuan <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/platform_device.h>
> +#include <linux/logic_pio.h>
> +
> +#include <acpi/acpi_indirect_pio.h>
> +
> +ACPI_MODULE_NAME("indirect PIO");
> +
> +#define INDIRECT_PIO_INFO(desc) ((unsigned long)&desc)
> +
> +static acpi_status acpi_count_logic_iores(struct acpi_resource *res,
> +					   void *data)
> +{
> +	int *res_cnt = data;
> +
> +	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO))
> +		(*res_cnt)++;
> +
> +	return AE_OK;
> +}
> +
> +static acpi_status acpi_read_one_logicpiores(struct acpi_resource *res,
> +		void *data)
> +{
> +	struct acpi_resource **resource = data;
> +
> +	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO)) {
> +		memcpy((*resource), res, sizeof(struct acpi_resource));
> +		(*resource)->length = sizeof(struct acpi_resource);
> +		(*resource)->type = res->type;
> +		(*resource)++;
> +	}
> +
> +	return AE_OK;
> +}
> +
> +static acpi_status
> +acpi_build_logicpiores_template(struct acpi_device *adev,
> +			struct acpi_buffer *buffer)
> +{
> +	acpi_handle handle = adev->handle;
> +	struct acpi_resource *resource;
> +	acpi_status status;
> +	int res_cnt = 0;
> +
> +	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> +				     acpi_count_logic_iores, &res_cnt);
> +	if (ACPI_FAILURE(status)) {
> +		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
> +		return -EINVAL;
> +	}
> +
> +	if (!res_cnt) {
> +		dev_err(&adev->dev, "no logic IO resources\n");
> +		return -ENODEV;
> +	}
> +
> +	buffer->length = sizeof(struct acpi_resource) * (res_cnt + 1);
> +	buffer->pointer = kzalloc(buffer->length, GFP_KERNEL);
> +	if (!buffer->pointer)
> +		return -ENOMEM;
> +
> +	resource = (struct acpi_resource *)buffer->pointer;
> +	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> +				     acpi_read_one_logicpiores, &resource);
> +	if (ACPI_FAILURE(status)) {
> +		kfree(buffer->pointer);
> +		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
> +		return -EINVAL;
> +	}
> +
> +	resource->type = ACPI_RESOURCE_TYPE_END_TAG;
> +	resource->length = sizeof(struct acpi_resource);
> +
> +	return 0;
> +}

IIUC correctly this code is here to count resources and replace them
with kernel specific IO offsets and I think that's wrong. ACPI devices
_CRS,_PRS,_SRS are set-up by firmware and by no means should be updated
with resources that are basically Linux kernel internals specific.

The problem you are facing is there because there is no way in ACPI
to specify in FW what you want to describe but that's not a reason
to make it work by other means.

[...]

> + * update/set the current I/O resource of the designated device node.
> + * after this calling, the enumeration can be started as the I/O resource
> + * had been translated to logicial I/O from bus-local I/O.
> + *
> + * @adev: the device node to be updated the I/O resource;
> + * @host: the device node where 'adev' is attached, which can be not
> + *	the parent of 'adev';
> + *
> + * return 0 when successful, negative is for failure.
> + */
> +int acpi_set_logic_pio_resource(struct device *child,
> +		struct device *hostdev)
> +{
> +	struct acpi_device *adev;
> +	struct acpi_device *host;
> +	struct acpi_buffer buffer;
> +	acpi_status status;
> +	int ret;
> +
> +	if (!child || !hostdev)
> +		return -EINVAL;
> +
> +	host = to_acpi_device(hostdev);
> +	adev = to_acpi_device(child);
> +
> +	/* check the device state */
> +	if (!adev->status.present) {
> +		dev_info(child, "ACPI: device is not present!\n");
> +		return 0;
> +	}
> +	/* whether the child had been enumerated? */
> +	if (acpi_device_enumerated(adev)) {
> +		dev_info(child, "ACPI: had been enumerated!\n");
> +		return 0;
> +	}
> +
> +	/* read the _CRS and convert as acpi_buffer */
> +	status = acpi_build_logicpiores_template(adev, &buffer);
> +	if (ACPI_FAILURE(status)) {
> +		dev_warn(child, "Failure evaluating %s\n", METHOD_NAME__CRS);
> +		return -ENODEV;
> +	}
> +
> +	/* translate the I/O resources */
> +	ret = acpi_translate_logicpiores(adev, host, &buffer);
> +	if (ret) {
> +		kfree(buffer.pointer);
> +		dev_err(child, "Translate I/O range FAIL!\n");
> +		return ret;
> +	}
> +
> +	/* set current resource... */
> +	status = acpi_set_current_resources(adev->handle, &buffer);

I reckon that this is wrong. You are updating ACPI device resources with
kernel specific built resources (ie IO space offsets) made by slicing up
IO space into the kernel available virtual address space offset
allocated to it.

IIUC this is done to make sure platform devices contains the
"translated" resources by the time they are probed, it is hard
to follow and again, not correct from an ACPI standpoint.

Furthermore I have no idea how this code is supposed to be used by
_any_ other platform, ACPI just has no notion of the translation you
are carrying out here (which mirrors what's done in DT without any
firmware binding to support it) so even if any other platform has
the same requirements I have no idea how people developing FW may
write their bindings to match these given that they just don't exist.

> +	kfree(buffer.pointer);
> +	if (ACPI_FAILURE(status)) {
> +		dev_err(child, "Error evaluating _SRS (0x%x)\n", status);
> +		ret = -EIO;
> +	}
> +
> +	return ret;
> +}
> +
> +/* All the host devices which apply indirect-PIO can be listed here. */
> +static const struct acpi_device_id acpi_indirect_host_id[] = {
> +	{""},

How can this be used by any other platform other than Hisilicon LPC ?

Imagine for a minute you have an ARM64 platform with an LPC bus in it
and you have to write ACPI tables to describe it, you may not want
to start by reading Linux kernel code to understand how to do it.

This code is Hisilicon specific code (ie there is no ACPI binding to
the best of my knowledge describing to FW developers an LPC binding)
and on the ACPI side it makes assumptions that I am not sure are
correct at all, see above.

> +};
> +
> +static int acpi_indirectpio_attach(struct acpi_device *adev,
> +				const struct acpi_device_id *id)
> +{
> +	struct indirect_pio_device_desc *hostdata;
> +	struct platform_device *pdev;
> +	int ret;
> +
> +	hostdata = (struct indirect_pio_device_desc *)id->driver_data;
> +	if (!hostdata || !hostdata->pre_setup)
> +		return -EINVAL;
> +
> +	ret = hostdata->pre_setup(adev, hostdata->pdata);
> +	if (!ret) {
> +		pdev = acpi_create_platform_device(adev, NULL);

So, this is done through a scan handler for what reason ? Is this
because you want this code to run before platform devices are created
by ACPI core - so that you can update their resources in the

struct indirect_pio_device_desc.pre_setup() method ?

I suspect this is yet another probing order issue to solve but that's
orthogonal to the comments I made above.

To sum it up:

(1) Creating an ARM64 ACPI standard kernel layer to parse something that is
    not an ACPI (let alone ARM64) standard does not make much sense to me,
    so either standard bindings are published for other partners to use
    them or this code belongs to Hisilicon specific LPC bus management
(2) Even with (1), I have concerns about this patch ACPI resources
    handling, I really think it is wrong to update ACPI devices
    resources with something that is Linux kernel specific. I may
    understand building platform devices resources according to your
    LPC bus requirements but not updating ACPI device FW bindings with
    resources that are basically kernel internals.

Thanks,
Lorenzo

> +		if (IS_ERR_OR_NULL(pdev)) {
> +			dev_err(&adev->dev, "Create platform device for host FAIL!\n");
> +			return -EFAULT;
> +		}
> +		acpi_device_set_enumerated(adev);
> +		ret = 1;
> +	}
> +
> +	return ret;
> +}
> +
> +
> +static struct acpi_scan_handler acpi_indirect_handler = {
> +	.ids = acpi_indirect_host_id,
> +	.attach = acpi_indirectpio_attach,
> +};
> +
> +void __init acpi_indirectio_scan_init(void)
> +{
> +	acpi_scan_add_handler(&acpi_indirect_handler);
> +}
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 66229ff..bf8aaf8 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -31,6 +31,11 @@ void acpi_processor_init(void);
>  void acpi_platform_init(void);
>  void acpi_pnp_init(void);
>  void acpi_int340x_thermal_init(void);
> +#ifdef CONFIG_INDIRECT_PIO
> +void acpi_indirectio_scan_init(void);
> +#else
> +static inline void acpi_indirectio_scan_init(void) {}
> +#endif
>  #ifdef CONFIG_ARM_AMBA
>  void acpi_amba_init(void);
>  #else
> diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> index e39ec7b..37dd23c 100644
> --- a/drivers/acpi/scan.c
> +++ b/drivers/acpi/scan.c
> @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
>  	acpi_int340x_thermal_init();
>  	acpi_amba_init();
>  	acpi_watchdog_init();
> +	acpi_indirectio_scan_init();
>  
>  	acpi_scan_add_handler(&generic_device_handler);
>  
> diff --git a/include/acpi/acpi_indirect_pio.h b/include/acpi/acpi_indirect_pio.h
> new file mode 100644
> index 0000000..efc5c43
> --- /dev/null
> +++ b/include/acpi/acpi_indirect_pio.h
> @@ -0,0 +1,24 @@
> +/*
> + * ACPI support for indirect-PIO bus.
> + *
> + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> + * Author: Gabriele Paoloni <[e-mail]>
> + * Author: Zhichang Yuan <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef _ACPI_INDIRECT_PIO_H
> +#define _ACPI_INDIRECT_PIO_H
> +
> +struct indirect_pio_device_desc {
> +	void *pdata; /* device relevant info data */
> +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> +};
> +
> +int acpi_set_logic_pio_resource(struct device *child,
> +		struct device *hostdev);
> +
> +#endif
> -- 
> 2.7.4
> 
>

Gabriele Paoloni May 31, 2017, 10:24 a.m. UTC | #3

Hi Lorenzo

Many thanks for reviewing

> -----Original Message-----
> From: Lorenzo Pieralisi [mailto:[e-mail]]
> Sent: 30 May 2017 14:24
> To: Gabriele Paoloni
> Cc: [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; linux-
> [e-mail]; Linuxarm; [e-mail];
> [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> Hi Gab,
> 
> On Thu, May 25, 2017 at 12:37:26PM +0100, Gabriele Paoloni wrote:
> > From: Gabriele <[e-mail]>
> >
> > On some platforms(such as Hip06/Hip07), the legacy ISA/LPC devices
> access
> > I/O with some special host-local I/O ports known on x86. As their I/O
> > space are not memory mapped like PCI/PCIE MMIO host bridges, this
> patch is
> > meant to support a new class of I/O host controllers where the local
> IO
> > ports of the children devices are translated into the Indirect I/O
> address
> > space.
> > Through the handler attach callback, all the I/O translations are
> done
> > before starting the enumeration on children devices and the
> translated
> > addresses are replaced in the children resources.
> 
> I do not understand why this is done through a scan handler and to
> be frank I do not see how this mechanism is supposed to be a generic
> kernel layer, possibly used by other platforms, when there is no notion
> in ACPI to cater for that.

Well, the main reason is that we need to translate the bus addresses of
the LPC children before the respective children's drivers probe.

> 
> As far as I am concerned this patch code should live in the Hisilicon
> LPC driver - as things stand it is neither ACPI generic code nor ARM64
> specific, it is code to make ACPI work like DT bindings without any
> ACPI
> binding at all; I still have some concerns from an ACPI standpoint
> below.

Well the reason why this patch cannot live in the LPC driver probe is
that AFAIK currently there is no way to guarantee the LPC probe to be
called before the children probe. With respect to the ACPI concerns
please see below.

> 
> > Signed-off-by: zhichang.yuan <[e-mail]>
> > Signed-off-by: Gabriele Paoloni <[e-mail]>
> > ---
> >  drivers/acpi/arm64/Makefile            |   1 +
> >  drivers/acpi/arm64/acpi_indirect_pio.c | 301
> +++++++++++++++++++++++++++++++++
> >  drivers/acpi/internal.h                |   5 +
> >  drivers/acpi/scan.c                    |   1 +
> >  include/acpi/acpi_indirect_pio.h       |  24 +++
> >  5 files changed, 332 insertions(+)
> >  create mode 100644 drivers/acpi/arm64/acpi_indirect_pio.c
> >  create mode 100644 include/acpi/acpi_indirect_pio.h
> >
> > diff --git a/drivers/acpi/arm64/Makefile
> b/drivers/acpi/arm64/Makefile
> > index 1017def..3944775 100644
> > --- a/drivers/acpi/arm64/Makefile
> > +++ b/drivers/acpi/arm64/Makefile
> > @@ -1,2 +1,3 @@
> >  obj-$(CONFIG_ACPI_IORT) 	+= iort.o
> >  obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
> > +obj-$(CONFIG_INDIRECT_PIO) += acpi_indirect_pio.o
> > diff --git a/drivers/acpi/arm64/acpi_indirect_pio.c
> b/drivers/acpi/arm64/acpi_indirect_pio.c
> > new file mode 100644
> > index 0000000..7813f73
> > --- /dev/null
> > +++ b/drivers/acpi/arm64/acpi_indirect_pio.c
> > @@ -0,0 +1,301 @@
> > +/*
> > + * ACPI support for indirect-PIO bus.
> > + *
> > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > + * Author: Gabriele Paoloni <[e-mail]>
> > + * Author: Zhichang Yuan <[e-mail]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/logic_pio.h>
> > +
> > +#include <acpi/acpi_indirect_pio.h>
> > +
> > +ACPI_MODULE_NAME("indirect PIO");
> > +
> > +#define INDIRECT_PIO_INFO(desc) ((unsigned long)&desc)
> > +
> > +static acpi_status acpi_count_logic_iores(struct acpi_resource *res,
> > +					   void *data)
> > +{
> > +	int *res_cnt = data;
> > +
> > +	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO))
> > +		(*res_cnt)++;
> > +
> > +	return AE_OK;
> > +}
> > +
> > +static acpi_status acpi_read_one_logicpiores(struct acpi_resource
> *res,
> > +		void *data)
> > +{
> > +	struct acpi_resource **resource = data;
> > +
> > +	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO)) {
> > +		memcpy((*resource), res, sizeof(struct acpi_resource));
> > +		(*resource)->length = sizeof(struct acpi_resource);
> > +		(*resource)->type = res->type;
> > +		(*resource)++;
> > +	}
> > +
> > +	return AE_OK;
> > +}
> > +
> > +static acpi_status
> > +acpi_build_logicpiores_template(struct acpi_device *adev,
> > +			struct acpi_buffer *buffer)
> > +{
> > +	acpi_handle handle = adev->handle;
> > +	struct acpi_resource *resource;
> > +	acpi_status status;
> > +	int res_cnt = 0;
> > +
> > +	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> > +				     acpi_count_logic_iores, &res_cnt);
> > +	if (ACPI_FAILURE(status)) {
> > +		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!res_cnt) {
> > +		dev_err(&adev->dev, "no logic IO resources\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	buffer->length = sizeof(struct acpi_resource) * (res_cnt + 1);
> > +	buffer->pointer = kzalloc(buffer->length, GFP_KERNEL);
> > +	if (!buffer->pointer)
> > +		return -ENOMEM;
> > +
> > +	resource = (struct acpi_resource *)buffer->pointer;
> > +	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
> > +				     acpi_read_one_logicpiores, &resource);
> > +	if (ACPI_FAILURE(status)) {
> > +		kfree(buffer->pointer);
> > +		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
> > +		return -EINVAL;
> > +	}
> > +
> > +	resource->type = ACPI_RESOURCE_TYPE_END_TAG;
> > +	resource->length = sizeof(struct acpi_resource);
> > +
> > +	return 0;
> > +}
> 
> IIUC correctly this code is here to count resources and replace them
> with kernel specific IO offsets and I think that's wrong. ACPI devices
> _CRS,_PRS,_SRS are set-up by firmware and by no means should be updated
> with resources that are basically Linux kernel internals specific.
> 
> The problem you are facing is there because there is no way in ACPI
> to specify in FW what you want to describe but that's not a reason
> to make it work by other means.

Mmmm yes I agree with you about not touching the ACPI resources (that indeed
should reflect what we have in the ACPI tables).

However I was thinking that maybe we can have a scan handler that enumerate
the children devices and translate its addresses filling dev->resources[] and
at the same time we can modify acpi_default_enumeration to check
acpi_device_enumerated() before continuing with device enumeration...?

> 
> [...]
> 
> > + * update/set the current I/O resource of the designated device
> node.
> > + * after this calling, the enumeration can be started as the I/O
> resource
> > + * had been translated to logicial I/O from bus-local I/O.
> > + *
> > + * @adev: the device node to be updated the I/O resource;
> > + * @host: the device node where 'adev' is attached, which can be not
> > + *	the parent of 'adev';
> > + *
> > + * return 0 when successful, negative is for failure.
> > + */
> > +int acpi_set_logic_pio_resource(struct device *child,
> > +		struct device *hostdev)
> > +{
> > +	struct acpi_device *adev;
> > +	struct acpi_device *host;
> > +	struct acpi_buffer buffer;
> > +	acpi_status status;
> > +	int ret;
> > +
> > +	if (!child || !hostdev)
> > +		return -EINVAL;
> > +
> > +	host = to_acpi_device(hostdev);
> > +	adev = to_acpi_device(child);
> > +
> > +	/* check the device state */
> > +	if (!adev->status.present) {
> > +		dev_info(child, "ACPI: device is not present!\n");
> > +		return 0;
> > +	}
> > +	/* whether the child had been enumerated? */
> > +	if (acpi_device_enumerated(adev)) {
> > +		dev_info(child, "ACPI: had been enumerated!\n");
> > +		return 0;
> > +	}
> > +
> > +	/* read the _CRS and convert as acpi_buffer */
> > +	status = acpi_build_logicpiores_template(adev, &buffer);
> > +	if (ACPI_FAILURE(status)) {
> > +		dev_warn(child, "Failure evaluating %s\n",
> METHOD_NAME__CRS);
> > +		return -ENODEV;
> > +	}
> > +
> > +	/* translate the I/O resources */
> > +	ret = acpi_translate_logicpiores(adev, host, &buffer);
> > +	if (ret) {
> > +		kfree(buffer.pointer);
> > +		dev_err(child, "Translate I/O range FAIL!\n");
> > +		return ret;
> > +	}
> > +
> > +	/* set current resource... */
> > +	status = acpi_set_current_resources(adev->handle, &buffer);
> 
> I reckon that this is wrong. You are updating ACPI device resources
> with
> kernel specific built resources (ie IO space offsets) made by slicing
> up
> IO space into the kernel available virtual address space offset
> allocated to it.
> 
> IIUC this is done to make sure platform devices contains the
> "translated" resources by the time they are probed, it is hard
> to follow and again, not correct from an ACPI standpoint.
> 
> Furthermore I have no idea how this code is supposed to be used by
> _any_ other platform, ACPI just has no notion of the translation you
> are carrying out here (which mirrors what's done in DT without any
> firmware binding to support it) so even if any other platform has
> the same requirements I have no idea how people developing FW may
> write their bindings to match these given that they just don't exist.

Agreed see proposal above

> 
> > +	kfree(buffer.pointer);
> > +	if (ACPI_FAILURE(status)) {
> > +		dev_err(child, "Error evaluating _SRS (0x%x)\n", status);
> > +		ret = -EIO;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +/* All the host devices which apply indirect-PIO can be listed here.
> */
> > +static const struct acpi_device_id acpi_indirect_host_id[] = {
> > +	{""},
> 
> How can this be used by any other platform other than Hisilicon LPC ?

The pre_setup() callback is host specific. It would be used by any other
host that needs to enumerate its children with logic PIOs rather than bus
addresses  

> 
> Imagine for a minute you have an ARM64 platform with an LPC bus in it
> and you have to write ACPI tables to describe it, you may not want
> to start by reading Linux kernel code to understand how to do it.

Well you don't really need to do it. I agree that it is wrong to manipulate
directly the acpi resources; however the translation process would be
independent of the bus addresses to be used in the ACPI tables...

> 
> This code is Hisilicon specific code (ie there is no ACPI binding to
> the best of my knowledge describing to FW developers an LPC binding)
> and on the ACPI side it makes assumptions that I am not sure are
> correct at all, see above.
> 
> > +};
> > +
> > +static int acpi_indirectpio_attach(struct acpi_device *adev,
> > +				const struct acpi_device_id *id)
> > +{
> > +	struct indirect_pio_device_desc *hostdata;
> > +	struct platform_device *pdev;
> > +	int ret;
> > +
> > +	hostdata = (struct indirect_pio_device_desc *)id->driver_data;
> > +	if (!hostdata || !hostdata->pre_setup)
> > +		return -EINVAL;
> > +
> > +	ret = hostdata->pre_setup(adev, hostdata->pdata);
> > +	if (!ret) {
> > +		pdev = acpi_create_platform_device(adev, NULL);
> 
> So, this is done through a scan handler for what reason ? Is this
> because you want this code to run before platform devices are created
> by ACPI core - so that you can update their resources in the
> 
> struct indirect_pio_device_desc.pre_setup() method ?
> 
> I suspect this is yet another probing order issue to solve but that's
> orthogonal to the comments I made above.

Correct :) see above

> 
> To sum it up:
> 
> (1) Creating an ARM64 ACPI standard kernel layer to parse something
> that is
>     not an ACPI (let alone ARM64) standard does not make much sense to
> me,
>     so either standard bindings are published for other partners to use
>     them or this code belongs to Hisilicon specific LPC bus management
> (2) Even with (1), I have concerns about this patch ACPI resources
>     handling, I really think it is wrong to update ACPI devices
>     resources with something that is Linux kernel specific. I may
>     understand building platform devices resources according to your
>     LPC bus requirements but not updating ACPI device FW bindings with
>     resources that are basically kernel internals.

On (2) I agree (please see proposal above)
On (1) I am not very sure about any binding needed at all...in the end
we are mapping a bus range into a virtual IO address space (Logic PIO)...

Cheers
Gab

> 
> Thanks,
> Lorenzo
> 
> > +		if (IS_ERR_OR_NULL(pdev)) {
> > +			dev_err(&adev->dev, "Create platform device for host
> FAIL!\n");
> > +			return -EFAULT;
> > +		}
> > +		acpi_device_set_enumerated(adev);
> > +		ret = 1;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +
> > +static struct acpi_scan_handler acpi_indirect_handler = {
> > +	.ids = acpi_indirect_host_id,
> > +	.attach = acpi_indirectpio_attach,
> > +};
> > +
> > +void __init acpi_indirectio_scan_init(void)
> > +{
> > +	acpi_scan_add_handler(&acpi_indirect_handler);
> > +}
> > diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> > index 66229ff..bf8aaf8 100644
> > --- a/drivers/acpi/internal.h
> > +++ b/drivers/acpi/internal.h
> > @@ -31,6 +31,11 @@ void acpi_processor_init(void);
> >  void acpi_platform_init(void);
> >  void acpi_pnp_init(void);
> >  void acpi_int340x_thermal_init(void);
> > +#ifdef CONFIG_INDIRECT_PIO
> > +void acpi_indirectio_scan_init(void);
> > +#else
> > +static inline void acpi_indirectio_scan_init(void) {}
> > +#endif
> >  #ifdef CONFIG_ARM_AMBA
> >  void acpi_amba_init(void);
> >  #else
> > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > index e39ec7b..37dd23c 100644
> > --- a/drivers/acpi/scan.c
> > +++ b/drivers/acpi/scan.c
> > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> >  	acpi_int340x_thermal_init();
> >  	acpi_amba_init();
> >  	acpi_watchdog_init();
> > +	acpi_indirectio_scan_init();
> >
> >  	acpi_scan_add_handler(&generic_device_handler);
> >
> > diff --git a/include/acpi/acpi_indirect_pio.h
> b/include/acpi/acpi_indirect_pio.h
> > new file mode 100644
> > index 0000000..efc5c43
> > --- /dev/null
> > +++ b/include/acpi/acpi_indirect_pio.h
> > @@ -0,0 +1,24 @@
> > +/*
> > + * ACPI support for indirect-PIO bus.
> > + *
> > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > + * Author: Gabriele Paoloni <[e-mail]>
> > + * Author: Zhichang Yuan <[e-mail]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> modify
> > + * it under the terms of the GNU General Public License version 2 as
> > + * published by the Free Software Foundation.
> > + */
> > +
> > +#ifndef _ACPI_INDIRECT_PIO_H
> > +#define _ACPI_INDIRECT_PIO_H
> > +
> > +struct indirect_pio_device_desc {
> > +	void *pdata; /* device relevant info data */
> > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > +};
> > +
> > +int acpi_set_logic_pio_resource(struct device *child,
> > +		struct device *hostdev);
> > +
> > +#endif
> > --
> > 2.7.4
> >
> >

Lorenzo Pieralisi June 6, 2017, 8:55 a.m. UTC | #4

Hi Gab, Rafael,

On Wed, May 31, 2017 at 10:24:47AM +0000, Gabriele Paoloni wrote:

[...]

> > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > index e39ec7b..37dd23c 100644
> > > --- a/drivers/acpi/scan.c
> > > +++ b/drivers/acpi/scan.c
> > > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> > >  	acpi_int340x_thermal_init();
> > >  	acpi_amba_init();
> > >  	acpi_watchdog_init();
> > > +	acpi_indirectio_scan_init();

Unfortunately this is becoming a pattern and we are ending up
with a static ordering of "subsystems" init (even though for this
LPC series it is just the Hisilicon driver that requires this call)
and I am not sure I see any way of avoiding it. I think that's always
been the case in x86, with fewer subsystems/kernel paths to care
about, I wanted to flag this up though to check your opinion since
I am not sure this is the right direction we are taking.

I also think that relying on _DEP to build any dependency is not
entirely a) usable (owing to legacy bindings and previous _DEP misuse)
and b) compliant with ACPI bindings given that _DEP has to be used
for operation regions only.

Thoughts ?

Thanks,
Lorenzo

> > >  	acpi_scan_add_handler(&generic_device_handler);
> > >
> > > diff --git a/include/acpi/acpi_indirect_pio.h
> > b/include/acpi/acpi_indirect_pio.h
> > > new file mode 100644
> > > index 0000000..efc5c43
> > > --- /dev/null
> > > +++ b/include/acpi/acpi_indirect_pio.h
> > > @@ -0,0 +1,24 @@
> > > +/*
> > > + * ACPI support for indirect-PIO bus.
> > > + *
> > > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > > + * Author: Gabriele Paoloni <[e-mail]>
> > > + * Author: Zhichang Yuan <[e-mail]>
> > > + *
> > > + * This program is free software; you can redistribute it and/or
> > modify
> > > + * it under the terms of the GNU General Public License version 2 as
> > > + * published by the Free Software Foundation.
> > > + */
> > > +
> > > +#ifndef _ACPI_INDIRECT_PIO_H
> > > +#define _ACPI_INDIRECT_PIO_H
> > > +
> > > +struct indirect_pio_device_desc {
> > > +	void *pdata; /* device relevant info data */
> > > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > > +};
> > > +
> > > +int acpi_set_logic_pio_resource(struct device *child,
> > > +		struct device *hostdev);
> > > +
> > > +#endif
> > > --
> > > 2.7.4
> > >
> > >

Lorenzo Pieralisi June 12, 2017, 3:57 p.m. UTC | #5

[+Mika]

Gab, Rafael,

On Tue, Jun 06, 2017 at 09:55:53AM +0100, Lorenzo Pieralisi wrote:
> Hi Gab, Rafael,
> 
> On Wed, May 31, 2017 at 10:24:47AM +0000, Gabriele Paoloni wrote:
> 
> [...]
> 
> > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > > index e39ec7b..37dd23c 100644
> > > > --- a/drivers/acpi/scan.c
> > > > +++ b/drivers/acpi/scan.c
> > > > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> > > >  	acpi_int340x_thermal_init();
> > > >  	acpi_amba_init();
> > > >  	acpi_watchdog_init();
> > > > +	acpi_indirectio_scan_init();
> 
> Unfortunately this is becoming a pattern and we are ending up
> with a static ordering of "subsystems" init (even though for this
> LPC series it is just the Hisilicon driver that requires this call)
> and I am not sure I see any way of avoiding it. I think that's always
> been the case in x86, with fewer subsystems/kernel paths to care
> about, I wanted to flag this up though to check your opinion since
> I am not sure this is the right direction we are taking.
> 
> I also think that relying on _DEP to build any dependency is not
> entirely a) usable (owing to legacy bindings and previous _DEP misuse)
> and b) compliant with ACPI bindings given that _DEP has to be used
> for operation regions only.

I had a more in-depth look at this series and from my understanding
the problem are the following to manage the LPC bindings in ACPI.

(1) Child devices of an LPC controller require special handling when
    filling their resources (ie they need to be translated - in DT
    that's guaranteed by the "isa" binding, in ACPI it has to be
    done by new code)
(2) In DT systems, LPC child devices are created by the LPC bus
    controller driver through an of_platform_populate() call with
    the LPC controller node as the fwnode root. For ACPI to work
    the same way there must be a way to prevent LPC children to
    be enumerated in acpi_default_enumeration() something like
    I2C does (and then the LPC driver would enumerate its children as
    DT does)

I am not sure how (1) and (2) can be managed with current ACPI bindings
and kernel code - I suspect it may be done by mirroring what's done
for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC adapter
is matched as a platform device and it takes care of enumerating its
children - problem though is preventing enumeration from core ACPI code).

I will let Gabriele and Hisilicon guys chime in if I missed something,
which is likely, please let me know your opinion on how this code
can be made functional on ACPI systems - it is uncharted territory.

Thank you !
Lorenzo

> 
> Thoughts ?
> 
> Thanks,
> Lorenzo
> 
> > > >  	acpi_scan_add_handler(&generic_device_handler);
> > > >
> > > > diff --git a/include/acpi/acpi_indirect_pio.h
> > > b/include/acpi/acpi_indirect_pio.h
> > > > new file mode 100644
> > > > index 0000000..efc5c43
> > > > --- /dev/null
> > > > +++ b/include/acpi/acpi_indirect_pio.h
> > > > @@ -0,0 +1,24 @@
> > > > +/*
> > > > + * ACPI support for indirect-PIO bus.
> > > > + *
> > > > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > > > + * Author: Gabriele Paoloni <[e-mail]>
> > > > + * Author: Zhichang Yuan <[e-mail]>
> > > > + *
> > > > + * This program is free software; you can redistribute it and/or
> > > modify
> > > > + * it under the terms of the GNU General Public License version 2 as
> > > > + * published by the Free Software Foundation.
> > > > + */
> > > > +
> > > > +#ifndef _ACPI_INDIRECT_PIO_H
> > > > +#define _ACPI_INDIRECT_PIO_H
> > > > +
> > > > +struct indirect_pio_device_desc {
> > > > +	void *pdata; /* device relevant info data */
> > > > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > > > +};
> > > > +
> > > > +int acpi_set_logic_pio_resource(struct device *child,
> > > > +		struct device *hostdev);
> > > > +
> > > > +#endif
> > > > --
> > > > 2.7.4
> > > >
> > > >

Gabriele Paoloni June 13, 2017, 7:24 a.m. UTC | #6

Hi Lorenzo, Rafael

> -----Original Message-----
> From: Lorenzo Pieralisi [mailto:[e-mail]]
> Sent: 12 June 2017 16:57
> To: Gabriele Paoloni; [e-mail]; Rafael J. Wysocki; Mika
> Westerberg
> Cc: [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> [+Mika]
> 
> Gab, Rafael,
> 
> On Tue, Jun 06, 2017 at 09:55:53AM +0100, Lorenzo Pieralisi wrote:
> > Hi Gab, Rafael,
> >
> > On Wed, May 31, 2017 at 10:24:47AM +0000, Gabriele Paoloni wrote:
> >
> > [...]
> >
> > > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > > > index e39ec7b..37dd23c 100644
> > > > > --- a/drivers/acpi/scan.c
> > > > > +++ b/drivers/acpi/scan.c
> > > > > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> > > > >  	acpi_int340x_thermal_init();
> > > > >  	acpi_amba_init();
> > > > >  	acpi_watchdog_init();
> > > > > +	acpi_indirectio_scan_init();
> >
> > Unfortunately this is becoming a pattern and we are ending up
> > with a static ordering of "subsystems" init (even though for this
> > LPC series it is just the Hisilicon driver that requires this call)
> > and I am not sure I see any way of avoiding it. I think that's always
> > been the case in x86, with fewer subsystems/kernel paths to care
> > about, I wanted to flag this up though to check your opinion since
> > I am not sure this is the right direction we are taking.
> >
> > I also think that relying on _DEP to build any dependency is not
> > entirely a) usable (owing to legacy bindings and previous _DEP
> misuse)
> > and b) compliant with ACPI bindings given that _DEP has to be used
> > for operation regions only.
> 
> I had a more in-depth look at this series and from my understanding
> the problem are the following to manage the LPC bindings in ACPI.
> 
> (1) Child devices of an LPC controller require special handling when
>     filling their resources (ie they need to be translated - in DT
>     that's guaranteed by the "isa" binding, in ACPI it has to be
>     done by new code)

Correct, LPC resources need to be translated in a virtual IO port
address space.
We cannot strictly follow the ISA bindings as the LPC host does not
define a mapping (through the "range" property) between a CPU address
range and an LPC address range.
Instead LPC has got his own bus accessors; therefore the bus address
range that LPC operates on is directly mapped into the IO port address
range and the IO in/out standard accessors (include/asm-generic/io.h)
are redefined to use the LPC accessors for the virtual IO port address
range that corresponds to LPC. 

> (2) In DT systems, LPC child devices are created by the LPC bus
>     controller driver through an of_platform_populate() call with
>     the LPC controller node as the fwnode root. For ACPI to work
>     the same way there must be a way to prevent LPC children to
>     be enumerated in acpi_default_enumeration() something like
>     I2C does (and then the LPC driver would enumerate its children as
>     DT does)

Correct.

> 
> I am not sure how (1) and (2) can be managed with current ACPI bindings
> and kernel code - I suspect it may be done by mirroring what's done
> for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC adapter
> is matched as a platform device and it takes care of enumerating its
> children - problem though is preventing enumeration from core ACPI
> code).

Yes my idea was to have a scan handler that enumerate the children devices
and translate its addresses filling dev->resources[] and at the same time
we can modify acpi_default_enumeration() to check acpi_device_enumerated()
before continuing with device enumeration...?

Many thanks
Gab

> 
> I will let Gabriele and Hisilicon guys chime in if I missed something,
> which is likely, please let me know your opinion on how this code
> can be made functional on ACPI systems - it is uncharted territory.
> 
> Thank you !
> Lorenzo
> 
> >
> > Thoughts ?
> >
> > Thanks,
> > Lorenzo
> >
> > > > >  	acpi_scan_add_handler(&generic_device_handler);
> > > > >
> > > > > diff --git a/include/acpi/acpi_indirect_pio.h
> > > > b/include/acpi/acpi_indirect_pio.h
> > > > > new file mode 100644
> > > > > index 0000000..efc5c43
> > > > > --- /dev/null
> > > > > +++ b/include/acpi/acpi_indirect_pio.h
> > > > > @@ -0,0 +1,24 @@
> > > > > +/*
> > > > > + * ACPI support for indirect-PIO bus.
> > > > > + *
> > > > > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > > > > + * Author: Gabriele Paoloni <[e-mail]>
> > > > > + * Author: Zhichang Yuan <[e-mail]>
> > > > > + *
> > > > > + * This program is free software; you can redistribute it
> and/or
> > > > modify
> > > > > + * it under the terms of the GNU General Public License
> version 2 as
> > > > > + * published by the Free Software Foundation.
> > > > > + */
> > > > > +
> > > > > +#ifndef _ACPI_INDIRECT_PIO_H
> > > > > +#define _ACPI_INDIRECT_PIO_H
> > > > > +
> > > > > +struct indirect_pio_device_desc {
> > > > > +	void *pdata; /* device relevant info data */
> > > > > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > > > > +};
> > > > > +
> > > > > +int acpi_set_logic_pio_resource(struct device *child,
> > > > > +		struct device *hostdev);
> > > > > +
> > > > > +#endif
> > > > > --
> > > > > 2.7.4
> > > > >
> > > > >

Mika Westerberg June 13, 2017, 8:48 a.m. UTC | #7

On Mon, Jun 12, 2017 at 04:57:00PM +0100, Lorenzo Pieralisi wrote:
> I had a more in-depth look at this series and from my understanding
> the problem are the following to manage the LPC bindings in ACPI.
> 
> (1) Child devices of an LPC controller require special handling when
>     filling their resources (ie they need to be translated - in DT
>     that's guaranteed by the "isa" binding, in ACPI it has to be
>     done by new code)
> (2) In DT systems, LPC child devices are created by the LPC bus
>     controller driver through an of_platform_populate() call with
>     the LPC controller node as the fwnode root. For ACPI to work
>     the same way there must be a way to prevent LPC children to
>     be enumerated in acpi_default_enumeration() something like
>     I2C does (and then the LPC driver would enumerate its children as
>     DT does)
> 
> I am not sure how (1) and (2) can be managed with current ACPI bindings
> and kernel code - I suspect it may be done by mirroring what's done
> for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC adapter
> is matched as a platform device and it takes care of enumerating its
> children - problem though is preventing enumeration from core ACPI code).

Is there an example ASL showing how these LPC devices are
currently presented in ACPI?

Gabriele Paoloni June 13, 2017, 2:38 p.m. UTC | #8

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:[e-mail]]
> Sent: 13 June 2017 09:49
> To: Lorenzo Pieralisi
> Cc: Gabriele Paoloni; [e-mail]; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> On Mon, Jun 12, 2017 at 04:57:00PM +0100, Lorenzo Pieralisi wrote:
> > I had a more in-depth look at this series and from my understanding
> > the problem are the following to manage the LPC bindings in ACPI.
> >
> > (1) Child devices of an LPC controller require special handling when
> >     filling their resources (ie they need to be translated - in DT
> >     that's guaranteed by the "isa" binding, in ACPI it has to be
> >     done by new code)
> > (2) In DT systems, LPC child devices are created by the LPC bus
> >     controller driver through an of_platform_populate() call with
> >     the LPC controller node as the fwnode root. For ACPI to work
> >     the same way there must be a way to prevent LPC children to
> >     be enumerated in acpi_default_enumeration() something like
> >     I2C does (and then the LPC driver would enumerate its children as
> >     DT does)
> >
> > I am not sure how (1) and (2) can be managed with current ACPI
> bindings
> > and kernel code - I suspect it may be done by mirroring what's done
> > for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC
> adapter
> > is matched as a platform device and it takes care of enumerating its
> > children - problem though is preventing enumeration from core ACPI
> code).
> 
> Is there an example ASL showing how these LPC devices are
> currently presented in ACPI?

Please find below the asl sketch for our LPC and IPMI

//
// LPC
//

Scope(_SB) {
  Device (LPC0) {
    Name (_HID, "HISI0191")  // HiSi LPC
    Name (_CRS, ResourceTemplate () {
      Memory32Fixed (ReadWrite, 0xa01b0000, 0x1000)
    })
  }

  Device (LPC0.IPMI) {
    Name (_HID, "IPI0001")
    Method (_IFT) {
      Return (0x03)
    }
    Name (LORS, ResourceTemplate() {
      QWordIO (
        ResourceConsumer,
	MinNotFixed,     // _MIF
	MaxNotFixed,     // _MAF
	PosDecode,
	EntireRange,
	0x0,             // _GRA
	0xe4,            // _MIN
	0x3fff,          // _MAX
	0x0,             // _TRA
	0x04,            // _LEN
	, ,
	BTIO
      )
    })
    CreateQWordField (LORS, BTIO._MIN, CMIN)
    CreateQWordField (LORS, BTIO._MAX, CMAX)
    CreateQWordField (LORS, BTIO._LEN, CLEN)

    Method (_PRS, 0) {
      Return (LORS)
    }

    Method (_CRS, 0) {
      Return (LORS)
    }
    Method (_SRS, 1) {
      CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MIN, IMIN)
      Store (IMIN, CMIN)
      CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MAX, IMAX)
      Store (IMAX, CMAX)
    }
  } 
[...]
}

Many thanks
Gab

Mika Westerberg June 13, 2017, 3:10 p.m. UTC | #9

On Tue, Jun 13, 2017 at 02:38:26PM +0000, Gabriele Paoloni wrote:
> > Is there an example ASL showing how these LPC devices are
> > currently presented in ACPI?
> 
> Please find below the asl sketch for our LPC and IPMI
> 
> //
> // LPC
> //
> 
> Scope(_SB) {
>   Device (LPC0) {
>     Name (_HID, "HISI0191")  // HiSi LPC
>     Name (_CRS, ResourceTemplate () {
>       Memory32Fixed (ReadWrite, 0xa01b0000, 0x1000)
>     })
>   }
> 
>   Device (LPC0.IPMI) {
>     Name (_HID, "IPI0001")
>     Method (_IFT) {
>       Return (0x03)
>     }
>     Name (LORS, ResourceTemplate() {
>       QWordIO (
>         ResourceConsumer,
> 	MinNotFixed,     // _MIF
> 	MaxNotFixed,     // _MAF
> 	PosDecode,
> 	EntireRange,
> 	0x0,             // _GRA
> 	0xe4,            // _MIN
> 	0x3fff,          // _MAX
> 	0x0,             // _TRA
> 	0x04,            // _LEN
> 	, ,
> 	BTIO
>       )
>     })
>     CreateQWordField (LORS, BTIO._MIN, CMIN)
>     CreateQWordField (LORS, BTIO._MAX, CMAX)
>     CreateQWordField (LORS, BTIO._LEN, CLEN)
> 
>     Method (_PRS, 0) {
>       Return (LORS)
>     }
> 
>     Method (_CRS, 0) {
>       Return (LORS)
>     }
>     Method (_SRS, 1) {
>       CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MIN, IMIN)
>       Store (IMIN, CMIN)
>       CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MAX, IMAX)
>       Store (IMAX, CMAX)
>     }
>   } 
> [...]
> }

Thanks. So this looks pretty much like normal Linux MFD device which we
already have support for adding ACPI bindings to child devices. It
should also support splitting resources to child devices IIRC.

Gabriele Paoloni June 13, 2017, 7:01 p.m. UTC | #10

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:[e-mail]]
> Sent: 13 June 2017 16:10
> To: Gabriele Paoloni
> Cc: Lorenzo Pieralisi; [e-mail]; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> On Tue, Jun 13, 2017 at 02:38:26PM +0000, Gabriele Paoloni wrote:
> > > Is there an example ASL showing how these LPC devices are
> > > currently presented in ACPI?
> >
> > Please find below the asl sketch for our LPC and IPMI
> >
> > //
> > // LPC
> > //
> >
> > Scope(_SB) {
> >   Device (LPC0) {
> >     Name (_HID, "HISI0191")  // HiSi LPC
> >     Name (_CRS, ResourceTemplate () {
> >       Memory32Fixed (ReadWrite, 0xa01b0000, 0x1000)
> >     })
> >   }
> >
> >   Device (LPC0.IPMI) {
> >     Name (_HID, "IPI0001")
> >     Method (_IFT) {
> >       Return (0x03)
> >     }
> >     Name (LORS, ResourceTemplate() {
> >       QWordIO (
> >         ResourceConsumer,
> > 	MinNotFixed,     // _MIF
> > 	MaxNotFixed,     // _MAF
> > 	PosDecode,
> > 	EntireRange,
> > 	0x0,             // _GRA
> > 	0xe4,            // _MIN
> > 	0x3fff,          // _MAX
> > 	0x0,             // _TRA
> > 	0x04,            // _LEN
> > 	, ,
> > 	BTIO
> >       )
> >     })
> >     CreateQWordField (LORS, BTIO._MIN, CMIN)
> >     CreateQWordField (LORS, BTIO._MAX, CMAX)
> >     CreateQWordField (LORS, BTIO._LEN, CLEN)
> >
> >     Method (_PRS, 0) {
> >       Return (LORS)
> >     }
> >
> >     Method (_CRS, 0) {
> >       Return (LORS)
> >     }
> >     Method (_SRS, 1) {
> >       CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MIN, IMIN)
> >       Store (IMIN, CMIN)
> >       CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MAX, IMAX)
> >       Store (IMAX, CMAX)
> >     }
> >   }
> > [...]
> > }
> 
> Thanks. So this looks pretty much like normal Linux MFD device which we
> already have support for adding ACPI bindings to child devices. It
> should also support splitting resources to child devices IIRC.

I am not very familiar with Linux MFD however the main issue here is that
1) for IPMI we want to re-use the standard IPMI driver without touching it:
   see 

   static const struct acpi_device_id acpi_ipmi_match[] = {
         { "IPI0001", 0 },
         { },
   };

   in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard driver
   of an LPC child)

2) We need a way to guarantee that all LPC children are not enumerated
   by acpi_default_enumeration() (so for example if an ipmi node is an LPC#
   child it should not be enumerated, otherwise it should be)
   Currently acpi_default_enumeration() skips spi/i2c slaves by checking:
   1) if the acpi resource type is a serial bus
   2) if the type of serial bus descriptor is I2C or SPI

   For LPC we cannot leverage on any ACPI property to "recognize" that our
   devices are LPC children; hence before I proposed for acpi_default_enumeration()
   to skip devices that have already been enumerated (by calling 
   acpi_device_enumerated() ).

So in the current scenario, how do you think that MFD can help?
Do you see any possible solution?

Many thanks
Gab

Mika Westerberg June 13, 2017, 8:03 p.m. UTC | #11

On Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> I am not very familiar with Linux MFD however the main issue here is that
> 1) for IPMI we want to re-use the standard IPMI driver without touching it:
>    see 
> 
>    static const struct acpi_device_id acpi_ipmi_match[] = {
>          { "IPI0001", 0 },
>          { },
>    };
> 
>    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard driver
>    of an LPC child)
> 
> 2) We need a way to guarantee that all LPC children are not enumerated
>    by acpi_default_enumeration() (so for example if an ipmi node is an LPC#
>    child it should not be enumerated, otherwise it should be)
>    Currently acpi_default_enumeration() skips spi/i2c slaves by checking:
>    1) if the acpi resource type is a serial bus
>    2) if the type of serial bus descriptor is I2C or SPI
> 
>    For LPC we cannot leverage on any ACPI property to "recognize" that our
>    devices are LPC children; hence before I proposed for acpi_default_enumeration()
>    to skip devices that have already been enumerated (by calling 
>    acpi_device_enumerated() ).
> 
> So in the current scenario, how do you think that MFD can help?

If you look at Documentation/acpi/enumeration.txt there is a chapter
"MFD devices". I think it pretty much maches what you have here. An LPC
device (MFD device) and bunch of child devices. The driver for your LPC
device can specify _HID for each child device. Those are then mached by
the MFD ACPI code to the corresponding ACPI nodes from which platform
devices are created including "IPI0001".

It causes acpi_default_enumeration() to be called but it should be fine
as we are dealing with platform device anyway.

Once the platform device is created your ipmi driver will be probed by
the driver core.

Does that make sense?

Gabriele Paoloni June 15, 2017, 6:01 p.m. UTC | #12

Hi Mika

> -----Original Message-----
> From: [e-mail] [mailto:linux-pci-
> [e-mail]] On Behalf Of Mika Westerberg
> Sent: 13 June 2017 21:04
> To: Gabriele Paoloni
> Cc: Lorenzo Pieralisi; [e-mail]; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> On Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> > I am not very familiar with Linux MFD however the main issue here is
> that
> > 1) for IPMI we want to re-use the standard IPMI driver without
> touching it:
> >    see
> >
> >    static const struct acpi_device_id acpi_ipmi_match[] = {
> >          { "IPI0001", 0 },
> >          { },
> >    };
> >
> >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
> driver
> >    of an LPC child)
> >
> > 2) We need a way to guarantee that all LPC children are not
> enumerated
> >    by acpi_default_enumeration() (so for example if an ipmi node is
> an LPC#
> >    child it should not be enumerated, otherwise it should be)
> >    Currently acpi_default_enumeration() skips spi/i2c slaves by
> checking:
> >    1) if the acpi resource type is a serial bus
> >    2) if the type of serial bus descriptor is I2C or SPI
> >
> >    For LPC we cannot leverage on any ACPI property to "recognize"
> that our
> >    devices are LPC children; hence before I proposed for
> acpi_default_enumeration()
> >    to skip devices that have already been enumerated (by calling
> >    acpi_device_enumerated() ).
> >
> > So in the current scenario, how do you think that MFD can help?
> 
> If you look at Documentation/acpi/enumeration.txt there is a chapter
> "MFD devices". I think it pretty much maches what you have here. An LPC
> device (MFD device) and bunch of child devices. The driver for your LPC
> device can specify _HID for each child device. Those are then mached by
> the MFD ACPI code to the corresponding ACPI nodes from which platform
> devices are created including "IPI0001".

So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:

	static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
		.pnpid = "IPI0001",
	};

correct?

> 
> It causes acpi_default_enumeration() to be called but it should be fine
> as we are dealing with platform device anyway.

I do not quite understand how declaring such MFD cell above would make sure
that the LPC probe is called before the IPMI device is enumerated...

Could you point me to the code that does this?

Many Thanks
Gab

> 
> Once the platform device is created your ipmi driver will be probed by
> the driver core.
> 
> Does that make sense?

Mika Westerberg June 16, 2017, 8:33 a.m. UTC | #13

On Thu, Jun 15, 2017 at 06:01:02PM +0000, Gabriele Paoloni wrote:
> Hi Mika
> 
> > -----Original Message-----
> > From: [e-mail] [mailto:linux-pci-
> > [e-mail]] On Behalf Of Mika Westerberg
> > Sent: 13 June 2017 21:04
> > To: Gabriele Paoloni
> > Cc: Lorenzo Pieralisi; [e-mail]; Rafael J. Wysocki;
> > [e-mail]; [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail]; linux-arm-
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail]; linux-
> > [e-mail]; [e-mail]; Linuxarm; linux-
> > [e-mail]; [e-mail]; John Garry; xuwei (O)
> > Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> > devices before scanning
> > 
> > On Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> > > I am not very familiar with Linux MFD however the main issue here is
> > that
> > > 1) for IPMI we want to re-use the standard IPMI driver without
> > touching it:
> > >    see
> > >
> > >    static const struct acpi_device_id acpi_ipmi_match[] = {
> > >          { "IPI0001", 0 },
> > >          { },
> > >    };
> > >
> > >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
> > driver
> > >    of an LPC child)
> > >
> > > 2) We need a way to guarantee that all LPC children are not
> > enumerated
> > >    by acpi_default_enumeration() (so for example if an ipmi node is
> > an LPC#
> > >    child it should not be enumerated, otherwise it should be)
> > >    Currently acpi_default_enumeration() skips spi/i2c slaves by
> > checking:
> > >    1) if the acpi resource type is a serial bus
> > >    2) if the type of serial bus descriptor is I2C or SPI
> > >
> > >    For LPC we cannot leverage on any ACPI property to "recognize"
> > that our
> > >    devices are LPC children; hence before I proposed for
> > acpi_default_enumeration()
> > >    to skip devices that have already been enumerated (by calling
> > >    acpi_device_enumerated() ).
> > >
> > > So in the current scenario, how do you think that MFD can help?
> > 
> > If you look at Documentation/acpi/enumeration.txt there is a chapter
> > "MFD devices". I think it pretty much maches what you have here. An LPC
> > device (MFD device) and bunch of child devices. The driver for your LPC
> > device can specify _HID for each child device. Those are then mached by
> > the MFD ACPI code to the corresponding ACPI nodes from which platform
> > devices are created including "IPI0001".
> 
> So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:
> 
> 	static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
> 		.pnpid = "IPI0001",
> 	};
> 
> correct?

Yes.

> > 
> > It causes acpi_default_enumeration() to be called but it should be fine
> > as we are dealing with platform device anyway.
> 
> I do not quite understand how declaring such MFD cell above would make sure
> that the LPC probe is called before the IPMI device is enumerated...

In fact it may be that it is not sufficient in this case because the
ACPI core might enumerate child devices before the LPC driver even gets
a chance to probe so you would need to add also scan handler to the
child devices and mark them already enumerated or something like that.

> Could you point me to the code that does this?

Check for example drivers/mfd/intel-lpss.c.

Rafael J. Wysocki June 16, 2017, 11:24 a.m. UTC | #14

On Fri, Jun 16, 2017 at 10:33 AM, Mika Westerberg
<[e-mail]> wrote:
> On Thu, Jun 15, 2017 at 06:01:02PM +0000, Gabriele Paoloni wrote:
>> Hi Mika
>>
>> > -----Original Message-----
>> > From: [e-mail] [mailto:linux-pci-
>> > [e-mail]] On Behalf Of Mika Westerberg
>> > Sent: 13 June 2017 21:04
>> > To: Gabriele Paoloni
>> > Cc: Lorenzo Pieralisi; [e-mail]; Rafael J. Wysocki;
>> > [e-mail]; [e-mail]; [e-mail];
>> > [e-mail]; [e-mail]; [e-mail]; linux-arm-
>> > [e-mail]; [e-mail];
>> > [e-mail]; [e-mail]; [e-mail]; linux-
>> > [e-mail]; [e-mail]; Linuxarm; linux-
>> > [e-mail]; [e-mail]; John Garry; xuwei (O)
>> > Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
>> > devices before scanning
>> >
>> > On Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
>> > > I am not very familiar with Linux MFD however the main issue here is
>> > that
>> > > 1) for IPMI we want to re-use the standard IPMI driver without
>> > touching it:
>> > >    see
>> > >
>> > >    static const struct acpi_device_id acpi_ipmi_match[] = {
>> > >          { "IPI0001", 0 },
>> > >          { },
>> > >    };
>> > >
>> > >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
>> > driver
>> > >    of an LPC child)
>> > >
>> > > 2) We need a way to guarantee that all LPC children are not
>> > enumerated
>> > >    by acpi_default_enumeration() (so for example if an ipmi node is
>> > an LPC#
>> > >    child it should not be enumerated, otherwise it should be)
>> > >    Currently acpi_default_enumeration() skips spi/i2c slaves by
>> > checking:
>> > >    1) if the acpi resource type is a serial bus
>> > >    2) if the type of serial bus descriptor is I2C or SPI
>> > >
>> > >    For LPC we cannot leverage on any ACPI property to "recognize"
>> > that our
>> > >    devices are LPC children; hence before I proposed for
>> > acpi_default_enumeration()
>> > >    to skip devices that have already been enumerated (by calling
>> > >    acpi_device_enumerated() ).
>> > >
>> > > So in the current scenario, how do you think that MFD can help?
>> >
>> > If you look at Documentation/acpi/enumeration.txt there is a chapter
>> > "MFD devices". I think it pretty much maches what you have here. An LPC
>> > device (MFD device) and bunch of child devices. The driver for your LPC
>> > device can specify _HID for each child device. Those are then mached by
>> > the MFD ACPI code to the corresponding ACPI nodes from which platform
>> > devices are created including "IPI0001".
>>
>> So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:
>>
>>       static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
>>               .pnpid = "IPI0001",
>>       };
>>
>> correct?
>
> Yes.
>
>> >
>> > It causes acpi_default_enumeration() to be called but it should be fine
>> > as we are dealing with platform device anyway.
>>
>> I do not quite understand how declaring such MFD cell above would make sure
>> that the LPC probe is called before the IPMI device is enumerated...
>
> In fact it may be that it is not sufficient in this case because the
> ACPI core might enumerate child devices before the LPC driver even gets
> a chance to probe so you would need to add also scan handler to the
> child devices and mark them already enumerated or something like that.

Or extend the special I2C/SPI handling to them.

Thanks,
Rafael

Mika Westerberg June 16, 2017, noon UTC | #15

On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
> > In fact it may be that it is not sufficient in this case because the
> > ACPI core might enumerate child devices before the LPC driver even gets
> > a chance to probe so you would need to add also scan handler to the
> > child devices and mark them already enumerated or something like that.
> 
> Or extend the special I2C/SPI handling to them.

Sure but those have I2c/SpiSerialBus() resources which we can use to
identify them but for the ipmi thing there is nothing else than _HID so
we would need to keep a list of such devices in ACPI core.

Rafael J. Wysocki June 16, 2017, 12:22 p.m. UTC | #16

On Fri, Jun 16, 2017 at 2:00 PM, Mika Westerberg
<[e-mail]> wrote:
> On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
>> > In fact it may be that it is not sufficient in this case because the
>> > ACPI core might enumerate child devices before the LPC driver even gets
>> > a chance to probe so you would need to add also scan handler to the
>> > child devices and mark them already enumerated or something like that.
>>
>> Or extend the special I2C/SPI handling to them.
>
> Sure but those have I2c/SpiSerialBus() resources which we can use to
> identify them but for the ipmi thing there is nothing else than _HID so
> we would need to keep a list of such devices in ACPI core.

OK, so adding a scan handler for that would be the way to go IMO.

Gabriele Paoloni June 19, 2017, 9:50 a.m. UTC | #17

Hi Rafael, Mika, Lorenzo

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> Rafael J. Wysocki
> Sent: 16 June 2017 13:23
> To: Mika Westerberg
> Cc: Rafael J. Wysocki; Gabriele Paoloni; Lorenzo Pieralisi; Rafael J.
> Wysocki; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; linux-
> [e-mail]; Linuxarm; [e-mail];
> [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> On Fri, Jun 16, 2017 at 2:00 PM, Mika Westerberg
> <[e-mail]> wrote:
> > On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
> >> > In fact it may be that it is not sufficient in this case because
> the
> >> > ACPI core might enumerate child devices before the LPC driver even
> gets
> >> > a chance to probe so you would need to add also scan handler to
> the
> >> > child devices and mark them already enumerated or something like
> that.
> >>
> >> Or extend the special I2C/SPI handling to them.
> >
> > Sure but those have I2c/SpiSerialBus() resources which we can use to
> > identify them but for the ipmi thing there is nothing else than _HID
> so
> > we would need to keep a list of such devices in ACPI core.
> 
> OK, so adding a scan handler for that would be the way to go IMO.

Many thanks for your response and your help here.

I guess that as conclusion with respect to the current v9 patchset we can
disregard the idea of MFD and modify the current v9 so that it doesn't
touch directly ACPI resources.
Instead as I proposed before we can have the scan handler to enumerate
the children devices and translate its addresses filling dev->resources[] and
at the same time we can modify acpi_default_enumeration to check
acpi_device_enumerated() before continuing with device enumeration...?

Do you think it as a viable solution?

Thanks
Gab

Mika Westerberg June 19, 2017, 10:02 a.m. UTC | #18

On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> Many thanks for your response and your help here.
> 
> I guess that as conclusion with respect to the current v9 patchset we can
> disregard the idea of MFD and modify the current v9 so that it doesn't
> touch directly ACPI resources.
> Instead as I proposed before we can have the scan handler to enumerate
> the children devices and translate its addresses filling dev->resources[] and
> at the same time we can modify acpi_default_enumeration to check
> acpi_device_enumerated() before continuing with device enumeration...?
> 
> Do you think it as a viable solution?

No, I think MFD + scan handler inside the MFD driver is the way to go.
We don't want to trash ACPI core with stuff that does not belong there
IMHO.

Also you don't need to modify acpi_default_enumeration() because you can
mark your device enumerated in the MFD driver. So all the dirty details
will be in the MFD driver and not in ACPI core.

Gabriele Paoloni June 19, 2017, 10:04 a.m. UTC | #19

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:[e-mail]]
> Sent: 19 June 2017 11:02
> To: Gabriele Paoloni
> Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> > Many thanks for your response and your help here.
> >
> > I guess that as conclusion with respect to the current v9 patchset we
> can
> > disregard the idea of MFD and modify the current v9 so that it
> doesn't
> > touch directly ACPI resources.
> > Instead as I proposed before we can have the scan handler to
> enumerate
> > the children devices and translate its addresses filling dev-
> >resources[] and
> > at the same time we can modify acpi_default_enumeration to check
> > acpi_device_enumerated() before continuing with device
> enumeration...?
> >
> > Do you think it as a viable solution?
> 
> No, I think MFD + scan handler inside the MFD driver is the way to go.
> We don't want to trash ACPI core with stuff that does not belong there
> IMHO.

Ok Many thanks I will investigate this direction 

> 
> Also you don't need to modify acpi_default_enumeration() because you
> can
> mark your device enumerated in the MFD driver. So all the dirty details
> will be in the MFD driver and not in ACPI core.

Ok got it :)

Cheers
Gab

John Garry June 29, 2017, 4:16 p.m. UTC | #20

On 16/06/2017 12:24, Rafael J. Wysocki wrote:
>>>> >> >
>>>> >> > It causes acpi_default_enumeration() to be called but it should be fine
>>>> >> > as we are dealing with platform device anyway.
>>> >>
>>> >> I do not quite understand how declaring such MFD cell above would make sure
>>> >> that the LPC probe is called before the IPMI device is enumerated...
>> >
>> > In fact it may be that it is not sufficient in this case because the
>> > ACPI core might enumerate child devices before the LPC driver even gets
>> > a chance to probe so you would need to add also scan handler to the
>> > child devices and mark them already enumerated or something like that.
> Or extend the special I2C/SPI handling to them.
>

For this, is it possible to just configure the ACPI table so we spoof 
that the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a 
resource of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus 
type i2c/spi to solve this?

This resource would/should need to be ignored for other purposes.

John

> Thanks,
> Rafael

Mika Westerberg June 30, 2017, 9:05 a.m. UTC | #21

On Thu, Jun 29, 2017 at 05:16:15PM +0100, John Garry wrote:
> On 16/06/2017 12:24, Rafael J. Wysocki wrote:
> > > > > >> >
> > > > > >> > It causes acpi_default_enumeration() to be called but it should be fine
> > > > > >> > as we are dealing with platform device anyway.
> > > > >>
> > > > >> I do not quite understand how declaring such MFD cell above would make sure
> > > > >> that the LPC probe is called before the IPMI device is enumerated...
> > > >
> > > > In fact it may be that it is not sufficient in this case because the
> > > > ACPI core might enumerate child devices before the LPC driver even gets
> > > > a chance to probe so you would need to add also scan handler to the
> > > > child devices and mark them already enumerated or something like that.
> > Or extend the special I2C/SPI handling to them.
> > 
> 
> For this, is it possible to just configure the ACPI table so we spoof that
> the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a resource
> of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus type i2c/spi to
> solve this?

But is the device connected to a I2C or SPI bus? If not, then it does
not make much sense to declare it as I2C or SPI slave. Instead it should
be platform device which is the type we use when there is no explicit
bus specified in ACPI.

John Garry June 30, 2017, 9:28 a.m. UTC | #22

On 30/06/2017 10:05, Mika Westerberg wrote:
> On Thu, Jun 29, 2017 at 05:16:15PM +0100, John Garry wrote:
>> On 16/06/2017 12:24, Rafael J. Wysocki wrote:
>>>>>>>>>
>>>>>>>>> It causes acpi_default_enumeration() to be called but it should be fine
>>>>>>>>> as we are dealing with platform device anyway.
>>>>>>>
>>>>>>> I do not quite understand how declaring such MFD cell above would make sure
>>>>>>> that the LPC probe is called before the IPMI device is enumerated...
>>>>>
>>>>> In fact it may be that it is not sufficient in this case because the
>>>>> ACPI core might enumerate child devices before the LPC driver even gets
>>>>> a chance to probe so you would need to add also scan handler to the
>>>>> child devices and mark them already enumerated or something like that.
>>> Or extend the special I2C/SPI handling to them.
>>>
>>
>> For this, is it possible to just configure the ACPI table so we spoof that
>> the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a resource
>> of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus type i2c/spi to
>> solve this?
>
> But is the device connected to a I2C or SPI bus? If not, then it does
> not make much sense to declare it as I2C or SPI slave. Instead it should
> be platform device which is the type we use when there is no explicit
> bus specified in ACPI.
>

No, it's not a SPI nor an I2C bus. I actually would say that my idea is 
generally wrong, as the ACPI definition is not a real reflection of the 
bus/slave.

However, Rafael did suggest extending special I2C/SPI handling to them. 
In this case, I don't see how the LPC slave can be identified like an 
I2C or SPI slave is.

Thanks,
John

> .
>

Rafael J. Wysocki June 30, 2017, 12:56 p.m. UTC | #23

On Fri, Jun 30, 2017 at 11:28 AM, John Garry <[e-mail]> wrote:
> On 30/06/2017 10:05, Mika Westerberg wrote:
>>
>> On Thu, Jun 29, 2017 at 05:16:15PM +0100, John Garry wrote:
>>>
>>> On 16/06/2017 12:24, Rafael J. Wysocki wrote:
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> It causes acpi_default_enumeration() to be called but it should be
>>>>>>>>>> fine
>>>>>>>>>> as we are dealing with platform device anyway.
>>>>>>>>
>>>>>>>>
>>>>>>>> I do not quite understand how declaring such MFD cell above would
>>>>>>>> make sure
>>>>>>>> that the LPC probe is called before the IPMI device is enumerated...
>>>>>>
>>>>>>
>>>>>> In fact it may be that it is not sufficient in this case because the
>>>>>> ACPI core might enumerate child devices before the LPC driver even
>>>>>> gets
>>>>>> a chance to probe so you would need to add also scan handler to the
>>>>>> child devices and mark them already enumerated or something like that.
>>>>
>>>> Or extend the special I2C/SPI handling to them.
>>>>
>>>
>>> For this, is it possible to just configure the ACPI table so we spoof
>>> that
>>> the LPC slave (IPI0001), is an i2c/spi slave? Could we just add a
>>> resource
>>> of type ACPI_RESOURCE_TYPE_SERIAL_BUS, and common serial bus type i2c/spi
>>> to
>>> solve this?
>>
>>
>> But is the device connected to a I2C or SPI bus? If not, then it does
>> not make much sense to declare it as I2C or SPI slave. Instead it should
>> be platform device which is the type we use when there is no explicit
>> bus specified in ACPI.
>>
>
> No, it's not a SPI nor an I2C bus. I actually would say that my idea is
> generally wrong, as the ACPI definition is not a real reflection of the
> bus/slave.
>
> However, Rafael did suggest extending special I2C/SPI handling to them. In
> this case, I don't see how the LPC slave can be identified like an I2C or
> SPI slave is.

I meant that it can be handled similarly (ie. as an exception from the
default enumeration), such that the enumeration is delayed until the
proper subsystem can enumerate those devices as appropriate.  Sorry
for the confusion.

Thanks,
Rafael

Gabriele Paoloni July 3, 2017, 4:08 p.m. UTC | #24

Hi Mika

> -----Original Message-----
> From: [e-mail] [mailto:linux-pci-
> [e-mail]] On Behalf Of Gabriele Paoloni
> Sent: 19 June 2017 11:05
> To: Mika Westerberg
> Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> Hi Mika
> 
> > -----Original Message-----
> > From: Mika Westerberg [mailto:[e-mail]]
> > Sent: 19 June 2017 11:02
> > To: Gabriele Paoloni
> > Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> > [e-mail]; [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail]; linux-
> arm-
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail];
> linux-
> > [e-mail]; [e-mail]; Linuxarm; linux-
> > [e-mail]; [e-mail]; John Garry; xuwei (O)
> > Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> > devices before scanning
> >
> > On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> > > Many thanks for your response and your help here.
> > >
> > > I guess that as conclusion with respect to the current v9 patchset
> we
> > can
> > > disregard the idea of MFD and modify the current v9 so that it
> > doesn't
> > > touch directly ACPI resources.
> > > Instead as I proposed before we can have the scan handler to
> > enumerate
> > > the children devices and translate its addresses filling dev-
> > >resources[] and
> > > at the same time we can modify acpi_default_enumeration to check
> > > acpi_device_enumerated() before continuing with device
> > enumeration...?
> > >
> > > Do you think it as a viable solution?
> >
> > No, I think MFD + scan handler inside the MFD driver is the way to
> go.
> > We don't want to trash ACPI core with stuff that does not belong
> there
> > IMHO.
> 
> Ok Many thanks I will investigate this direction

I had a look into the MFD framework. If my understanding is correct the mfd
framework create a platform device for each declared mfd_cell that is passed
to mfd_add_devices().
However there is something that I do not quite understand:
from
http://elixir.free-electrons.com/linux/latest/source/drivers/mfd/mfd-core.c#L207
it seems that mfd_add_device() will create the platform device using the
resources that are statically declared in the respective mfd_cell.

In my case I'd like to have a platform device using the resources that are
parsed from the ACPI table (i.e. as it is done now by 
acpi_create_platform_device()).

If my understanding is correct, if I declared an mfd_cell for my IPMI child
the mfd subsystem would create a platform device for such child and
therefore acpi_create_platform_device() would fail to create a new platform
device as adev->physical_node_count will be non zero.
However as things stand now mfd_cell devices can only use the resources
that are statically defined in the code (and therefore not the ones in the
ACPI nodes)...am I right?

Thanks
Gab

> 
> >
> > Also you don't need to modify acpi_default_enumeration() because you
> > can
> > mark your device enumerated in the MFD driver. So all the dirty
> details
> > will be in the MFD driver and not in ACPI core.
> 
> Ok got it :)
> 
> Cheers
> Gab

Gabriele Paoloni July 3, 2017, 4:23 p.m. UTC | #25

+CC Lee Jones

> -----Original Message-----
> From: Gabriele Paoloni
> Sent: 03 July 2017 17:08
> To: Gabriele Paoloni; Mika Westerberg
> Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> [e-mail]; [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-arm-
> [e-mail]; [e-mail];
> [e-mail]; [e-mail]; [e-mail]; linux-
> [e-mail]; [e-mail]; Linuxarm; linux-
> [e-mail]; [e-mail]; John Garry; xuwei (O)
> Subject: RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
> 
> Hi Mika
> 
> > -----Original Message-----
> > From: [e-mail] [mailto:linux-pci-
> > [e-mail]] On Behalf Of Gabriele Paoloni
> > Sent: 19 June 2017 11:05
> > To: Mika Westerberg
> > Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> > [e-mail]; [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail]; linux-
> arm-
> > [e-mail]; [e-mail];
> > [e-mail]; [e-mail]; [e-mail];
> linux-
> > [e-mail]; [e-mail]; Linuxarm; linux-
> > [e-mail]; [e-mail]; John Garry; xuwei (O)
> > Subject: RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> > devices before scanning
> >
> > Hi Mika
> >
> > > -----Original Message-----
> > > From: Mika Westerberg [mailto:[e-mail]]
> > > Sent: 19 June 2017 11:02
> > > To: Gabriele Paoloni
> > > Cc: Rafael J. Wysocki; Lorenzo Pieralisi; Rafael J. Wysocki;
> > > [e-mail]; [e-mail]; [e-mail];
> > > [e-mail]; [e-mail]; [e-mail]; linux-
> > arm-
> > > [e-mail]; [e-mail];
> > > [e-mail]; [e-mail]; [e-mail];
> > linux-
> > > [e-mail]; [e-mail]; Linuxarm;
> linux-
> > > [e-mail]; [e-mail]; John Garry; xuwei (O)
> > > Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-
> MMIO
> > > devices before scanning
> > >
> > > On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> > > > Many thanks for your response and your help here.
> > > >
> > > > I guess that as conclusion with respect to the current v9
> patchset
> > we
> > > can
> > > > disregard the idea of MFD and modify the current v9 so that it
> > > doesn't
> > > > touch directly ACPI resources.
> > > > Instead as I proposed before we can have the scan handler to
> > > enumerate
> > > > the children devices and translate its addresses filling dev-
> > > >resources[] and
> > > > at the same time we can modify acpi_default_enumeration to check
> > > > acpi_device_enumerated() before continuing with device
> > > enumeration...?
> > > >
> > > > Do you think it as a viable solution?
> > >
> > > No, I think MFD + scan handler inside the MFD driver is the way to
> > go.
> > > We don't want to trash ACPI core with stuff that does not belong
> > there
> > > IMHO.
> >
> > Ok Many thanks I will investigate this direction
> 
> I had a look into the MFD framework. If my understanding is correct the
> mfd
> framework create a platform device for each declared mfd_cell that is
> passed
> to mfd_add_devices().
> However there is something that I do not quite understand:
> from
> http://elixir.free-electrons.com/linux/latest/source/drivers/mfd/mfd-
> core.c#L207
> it seems that mfd_add_device() will create the platform device using
> the
> resources that are statically declared in the respective mfd_cell.
> 
> In my case I'd like to have a platform device using the resources that
> are
> parsed from the ACPI table (i.e. as it is done now by
> acpi_create_platform_device()).
> 
> If my understanding is correct, if I declared an mfd_cell for my IPMI
> child
> the mfd subsystem would create a platform device for such child and
> therefore acpi_create_platform_device() would fail to create a new
> platform
> device as adev->physical_node_count will be non zero.
> However as things stand now mfd_cell devices can only use the resources
> that are statically defined in the code (and therefore not the ones in
> the
> ACPI nodes)...am I right?
> 
> Thanks
> Gab
> 
> >
> > >
> > > Also you don't need to modify acpi_default_enumeration() because
> you
> > > can
> > > mark your device enumerated in the MFD driver. So all the dirty
> > details
> > > will be in the MFD driver and not in ACPI core.
> >
> > Ok got it :)
> >
> > Cheers
> > Gab

Andy Shevchenko July 3, 2017, 8:22 p.m. UTC | #26

On Mon, Jul 3, 2017 at 7:08 PM, Gabriele Paoloni
<[e-mail]> wrote:

JFYI: Mika on vacation.

> I had a look into the MFD framework. If my understanding is correct the mfd
> framework create a platform device for each declared mfd_cell that is passed
> to mfd_add_devices().

Right.

> However there is something that I do not quite understand:
> from
> http://elixir.free-electrons.com/linux/latest/source/drivers/mfd/mfd-core.c#L207
> it seems that mfd_add_device() will create the platform device using the
> resources that are statically declared in the respective mfd_cell.

It's one possibility.

> In my case I'd like to have a platform device using the resources that are
> parsed from the ACPI table (i.e. as it is done now by
> acpi_create_platform_device()).

So far so good. Nothing prevents you to do that.

> If my understanding is correct, if I declared an mfd_cell for my IPMI child
> the mfd subsystem would create a platform device for such child and
> therefore acpi_create_platform_device() would fail to create a new platform
> device as adev->physical_node_count will be non zero.
> However as things stand now mfd_cell devices can only use the resources
> that are statically defined in the code (and therefore not the ones in the
> ACPI nodes)...am I right?

You may file resources first and then register MFD cells. See many
existing examples in the kernel.

Gabriele Paoloni July 4, 2017, 3:14 p.m. UTC | #27

Hi Andy

[...]

> 
> JFYI: Mika on vacation.

Thanks for letting me know

> 
> > I had a look into the MFD framework. If my understanding is correct
> the mfd
> > framework create a platform device for each declared mfd_cell that is
> passed
> > to mfd_add_devices().
> 
> Right.
> 
> > However there is something that I do not quite understand:
> > from
> > http://elixir.free-electrons.com/linux/latest/source/drivers/mfd/mfd-
> core.c#L207
> > it seems that mfd_add_device() will create the platform device using
> the
> > resources that are statically declared in the respective mfd_cell.
> 
> It's one possibility.
> 
> > In my case I'd like to have a platform device using the resources
> that are
> > parsed from the ACPI table (i.e. as it is done now by
> > acpi_create_platform_device()).
> 
> So far so good. Nothing prevents you to do that.
> 
> > If my understanding is correct, if I declared an mfd_cell for my IPMI
> child
> > the mfd subsystem would create a platform device for such child and
> > therefore acpi_create_platform_device() would fail to create a new
> platform
> > device as adev->physical_node_count will be non zero.
> > However as things stand now mfd_cell devices can only use the
> resources
> > that are statically defined in the code (and therefore not the ones
> in the
> > ACPI nodes)...am I right?
> 
> You may file resources first and then register MFD cells. See many
> existing examples in the kernel.

Well I had a look around the Kernel I have seen no mfd cells using
Resources that are not statically defined:
i.e. cell->resources in mfd_add_device() always points to statically
defined resource structures.

Usually for ACPI devices first you need to parse the ACPI resources
from the table calling acpi_dev_get_resources(), then you iterate 
over the resource list and fill the resource array by calling
acpi_platform_fill_resurces() (as in acpi_create_platform_device())

With respect to my case are you suggesting dynamically allocate a
resource array and fill it using the same fashion as 
acpi_create_platform_device(), then point cell->resources to such
array before calling mfd_add_device() ?

Thanks
Gab

> 
> --
> With Best Regards,
> Andy Shevchenko

Andy Shevchenko July 4, 2017, 3:46 p.m. UTC | #28

On Tue, Jul 4, 2017 at 6:14 PM, Gabriele Paoloni
<[e-mail]> wrote:

>> > In my case I'd like to have a platform device using the resources
>> that are
>> > parsed from the ACPI table (i.e. as it is done now by
>> > acpi_create_platform_device()).
>>
>> So far so good. Nothing prevents you to do that.
>>
>> > If my understanding is correct, if I declared an mfd_cell for my IPMI
>> child
>> > the mfd subsystem would create a platform device for such child and
>> > therefore acpi_create_platform_device() would fail to create a new
>> platform
>> > device as adev->physical_node_count will be non zero.
>> > However as things stand now mfd_cell devices can only use the
>> resources
>> > that are statically defined in the code (and therefore not the ones
>> in the
>> > ACPI nodes)...am I right?
>>
>> You may file resources first and then register MFD cells. See many
>> existing examples in the kernel.
>
> Well I had a look around the Kernel I have seen no mfd cells using
> Resources that are not statically defined:
> i.e. cell->resources in mfd_add_device() always points to statically
> defined resource structures.
>
> Usually for ACPI devices first you need to parse the ACPI resources
> from the table calling acpi_dev_get_resources(), then you iterate
> over the resource list and fill the resource array by calling
> acpi_platform_fill_resurces() (as in acpi_create_platform_device())
>
> With respect to my case are you suggesting dynamically allocate a
> resource array and fill it using the same fashion as
> acpi_create_platform_device(), then point cell->resources to such
> array before calling mfd_add_device() ?

You may do it on stack. Define your cell statically (but not const)
and apply resources just before mfd_add_devices() call.
There are examples in the existing drivers. Intel LPC comes to my mind
and perhaps PMC (Broxton), though latter has too much other stuff
around.

Gabriele Paoloni July 4, 2017, 4:22 p.m. UTC | #29

Hi Andy

[...]

> 
> You may do it on stack. Define your cell statically (but not const)
> and apply resources just before mfd_add_devices() call.

Ok thanks got it

> There are examples in the existing drivers. Intel LPC comes to my mind
> and perhaps PMC (Broxton), though latter has too much other stuff
> around.

Uh yes I see now in lpc_ich.c (base address is read from PCI config space
and resources are set accordingly).

Cheers
Gab

> 
> --
> With Best Regards,
> Andy Shevchenko

Patch

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
index 1017def..3944775 100644
--- a/drivers/acpi/arm64/Makefile
+++ b/drivers/acpi/arm64/Makefile
@@ -1,2 +1,3 @@ 
 obj-$(CONFIG_ACPI_IORT) 	+= iort.o
 obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
+obj-$(CONFIG_INDIRECT_PIO) += acpi_indirect_pio.o
diff --git a/drivers/acpi/arm64/acpi_indirect_pio.c b/drivers/acpi/arm64/acpi_indirect_pio.c
new file mode 100644
index 0000000..7813f73
--- /dev/null
+++ b/drivers/acpi/arm64/acpi_indirect_pio.c
@@ -0,0 +1,301 @@ 
+/*
+ * ACPI support for indirect-PIO bus.
+ *
+ * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
+ * Author: Gabriele Paoloni <[e-mail]>
+ * Author: Zhichang Yuan <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+#include <linux/logic_pio.h>
+
+#include <acpi/acpi_indirect_pio.h>
+
+ACPI_MODULE_NAME("indirect PIO");
+
+#define INDIRECT_PIO_INFO(desc) ((unsigned long)&desc)
+
+static acpi_status acpi_count_logic_iores(struct acpi_resource *res,
+					   void *data)
+{
+	int *res_cnt = data;
+
+	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO))
+		(*res_cnt)++;
+
+	return AE_OK;
+}
+
+static acpi_status acpi_read_one_logicpiores(struct acpi_resource *res,
+		void *data)
+{
+	struct acpi_resource **resource = data;
+
+	if (!acpi_dev_filter_resource_type(res, IORESOURCE_IO)) {
+		memcpy((*resource), res, sizeof(struct acpi_resource));
+		(*resource)->length = sizeof(struct acpi_resource);
+		(*resource)->type = res->type;
+		(*resource)++;
+	}
+
+	return AE_OK;
+}
+
+static acpi_status
+acpi_build_logicpiores_template(struct acpi_device *adev,
+			struct acpi_buffer *buffer)
+{
+	acpi_handle handle = adev->handle;
+	struct acpi_resource *resource;
+	acpi_status status;
+	int res_cnt = 0;
+
+	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+				     acpi_count_logic_iores, &res_cnt);
+	if (ACPI_FAILURE(status)) {
+		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
+		return -EINVAL;
+	}
+
+	if (!res_cnt) {
+		dev_err(&adev->dev, "no logic IO resources\n");
+		return -ENODEV;
+	}
+
+	buffer->length = sizeof(struct acpi_resource) * (res_cnt + 1);
+	buffer->pointer = kzalloc(buffer->length, GFP_KERNEL);
+	if (!buffer->pointer)
+		return -ENOMEM;
+
+	resource = (struct acpi_resource *)buffer->pointer;
+	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
+				     acpi_read_one_logicpiores, &resource);
+	if (ACPI_FAILURE(status)) {
+		kfree(buffer->pointer);
+		dev_err(&adev->dev, "can't evaluate _CRS: %d\n", status);
+		return -EINVAL;
+	}
+
+	resource->type = ACPI_RESOURCE_TYPE_END_TAG;
+	resource->length = sizeof(struct acpi_resource);
+
+	return 0;
+}
+
+static int acpi_translate_logicpiores(struct acpi_device *adev,
+		struct acpi_device *host, struct acpi_buffer *buffer)
+{
+	struct acpi_resource *resource = buffer->pointer;
+	unsigned long sys_port;
+	struct device *dev = &adev->dev;
+	union acpi_resource_data *trans_data = &resource->data;
+	resource_size_t bus_addr;
+	resource_size_t max_pio;
+	resource_size_t length;
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_ADDRESS16:
+		if (trans_data->address16.min_address_fixed !=
+				trans_data->address16.max_address_fixed) {
+			dev_warn(dev, "variable I/O resource is invalid!\n");
+			return -EINVAL;
+		}
+		bus_addr = trans_data->address16.address.minimum;
+		length = trans_data->address16.address.address_length;
+		max_pio = U16_MAX;
+		break;
+	case ACPI_RESOURCE_TYPE_ADDRESS32:
+		if (trans_data->address32.min_address_fixed !=
+				trans_data->address32.max_address_fixed) {
+			dev_warn(dev, "variable I/O resource is invalid!\n");
+			return -EINVAL;
+		}
+		bus_addr = trans_data->address32.address.minimum;
+		length = trans_data->address32.address.address_length;
+		max_pio = U32_MAX;
+		break;
+	case ACPI_RESOURCE_TYPE_ADDRESS64:
+		if (trans_data->address64.min_address_fixed !=
+				trans_data->address64.max_address_fixed) {
+			dev_warn(dev, "variable I/O resource is invalid!\n");
+			return -EINVAL;
+		}
+		bus_addr = trans_data->address64.address.minimum;
+		length = trans_data->address64.address.address_length;
+		max_pio = U64_MAX;
+		break;
+	case ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64:
+		if (trans_data->ext_address64.min_address_fixed !=
+				trans_data->ext_address64.max_address_fixed) {
+			dev_warn(dev, "variable I/O resource is invalid!\n");
+			return -EINVAL;
+		}
+		bus_addr = trans_data->ext_address64.address.minimum;
+		length = trans_data->ext_address64.address.address_length;
+		max_pio = U64_MAX;
+		break;
+	case ACPI_RESOURCE_TYPE_IO:
+		bus_addr = trans_data->io.minimum;
+		length = trans_data->io.address_length;
+		max_pio = U16_MAX;
+		break;
+	case ACPI_RESOURCE_TYPE_FIXED_IO:
+		bus_addr = trans_data->fixed_io.address;
+		length = trans_data->fixed_io.address_length;
+		max_pio = U16_MAX;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	sys_port = logic_pio_trans_hwaddr(&host->fwnode, bus_addr);
+	if (sys_port == -1) {
+		dev_err(dev, "translate bus-addr(0x%llx) fail!\n", bus_addr);
+		return -EFAULT;
+	}
+
+	/*
+	 * we need to check if the resource address can contain the
+	 * translated IO token
+	 */
+	if ((sys_port + length) > max_pio) {
+		dev_err(dev, "sys_port exceeds the max resource address\n");
+		return -ENOSPC;
+	}
+
+	switch (resource->type) {
+	case ACPI_RESOURCE_TYPE_ADDRESS16:
+		trans_data->address16.address.minimum = sys_port;
+		trans_data->address16.address.maximum = sys_port + length;
+		break;
+	case ACPI_RESOURCE_TYPE_ADDRESS32:
+		trans_data->address32.address.minimum = sys_port;
+		trans_data->address32.address.maximum = sys_port + length;
+		break;
+	case ACPI_RESOURCE_TYPE_ADDRESS64:
+		trans_data->address64.address.minimum = sys_port;
+		trans_data->address64.address.maximum = sys_port + length;
+		break;
+	case ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64:
+		trans_data->ext_address64.address.minimum = sys_port;
+		trans_data->ext_address64.address.maximum = sys_port + length;
+		break;
+	case ACPI_RESOURCE_TYPE_IO:
+		trans_data->io.minimum = sys_port;
+		trans_data->io.maximum = sys_port + length;
+		break;
+	case ACPI_RESOURCE_TYPE_FIXED_IO:
+		trans_data->fixed_io.address = sys_port;
+		break;
+	}
+	return 0;
+}
+
+/*
+ * update/set the current I/O resource of the designated device node.
+ * after this calling, the enumeration can be started as the I/O resource
+ * had been translated to logicial I/O from bus-local I/O.
+ *
+ * @adev: the device node to be updated the I/O resource;
+ * @host: the device node where 'adev' is attached, which can be not
+ *	the parent of 'adev';
+ *
+ * return 0 when successful, negative is for failure.
+ */
+int acpi_set_logic_pio_resource(struct device *child,
+		struct device *hostdev)
+{
+	struct acpi_device *adev;
+	struct acpi_device *host;
+	struct acpi_buffer buffer;
+	acpi_status status;
+	int ret;
+
+	if (!child || !hostdev)
+		return -EINVAL;
+
+	host = to_acpi_device(hostdev);
+	adev = to_acpi_device(child);
+
+	/* check the device state */
+	if (!adev->status.present) {
+		dev_info(child, "ACPI: device is not present!\n");
+		return 0;
+	}
+	/* whether the child had been enumerated? */
+	if (acpi_device_enumerated(adev)) {
+		dev_info(child, "ACPI: had been enumerated!\n");
+		return 0;
+	}
+
+	/* read the _CRS and convert as acpi_buffer */
+	status = acpi_build_logicpiores_template(adev, &buffer);
+	if (ACPI_FAILURE(status)) {
+		dev_warn(child, "Failure evaluating %s\n", METHOD_NAME__CRS);
+		return -ENODEV;
+	}
+
+	/* translate the I/O resources */
+	ret = acpi_translate_logicpiores(adev, host, &buffer);
+	if (ret) {
+		kfree(buffer.pointer);
+		dev_err(child, "Translate I/O range FAIL!\n");
+		return ret;
+	}
+
+	/* set current resource... */
+	status = acpi_set_current_resources(adev->handle, &buffer);
+	kfree(buffer.pointer);
+	if (ACPI_FAILURE(status)) {
+		dev_err(child, "Error evaluating _SRS (0x%x)\n", status);
+		ret = -EIO;
+	}
+
+	return ret;
+}
+
+/* All the host devices which apply indirect-PIO can be listed here. */
+static const struct acpi_device_id acpi_indirect_host_id[] = {
+	{""},
+};
+
+static int acpi_indirectpio_attach(struct acpi_device *adev,
+				const struct acpi_device_id *id)
+{
+	struct indirect_pio_device_desc *hostdata;
+	struct platform_device *pdev;
+	int ret;
+
+	hostdata = (struct indirect_pio_device_desc *)id->driver_data;
+	if (!hostdata || !hostdata->pre_setup)
+		return -EINVAL;
+
+	ret = hostdata->pre_setup(adev, hostdata->pdata);
+	if (!ret) {
+		pdev = acpi_create_platform_device(adev, NULL);
+		if (IS_ERR_OR_NULL(pdev)) {
+			dev_err(&adev->dev, "Create platform device for host FAIL!\n");
+			return -EFAULT;
+		}
+		acpi_device_set_enumerated(adev);
+		ret = 1;
+	}
+
+	return ret;
+}
+
+
+static struct acpi_scan_handler acpi_indirect_handler = {
+	.ids = acpi_indirect_host_id,
+	.attach = acpi_indirectpio_attach,
+};
+
+void __init acpi_indirectio_scan_init(void)
+{
+	acpi_scan_add_handler(&acpi_indirect_handler);
+}
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 66229ff..bf8aaf8 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -31,6 +31,11 @@  void acpi_processor_init(void);
 void acpi_platform_init(void);
 void acpi_pnp_init(void);
 void acpi_int340x_thermal_init(void);
+#ifdef CONFIG_INDIRECT_PIO
+void acpi_indirectio_scan_init(void);
+#else
+static inline void acpi_indirectio_scan_init(void) {}
+#endif
 #ifdef CONFIG_ARM_AMBA
 void acpi_amba_init(void);
 #else
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e39ec7b..37dd23c 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2035,6 +2035,7 @@  int __init acpi_scan_init(void)
 	acpi_int340x_thermal_init();
 	acpi_amba_init();
 	acpi_watchdog_init();
+	acpi_indirectio_scan_init();
 
 	acpi_scan_add_handler(&generic_device_handler);
 
diff --git a/include/acpi/acpi_indirect_pio.h b/include/acpi/acpi_indirect_pio.h
new file mode 100644
index 0000000..efc5c43
--- /dev/null
+++ b/include/acpi/acpi_indirect_pio.h
@@ -0,0 +1,24 @@ 
+/*
+ * ACPI support for indirect-PIO bus.
+ *
+ * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
+ * Author: Gabriele Paoloni <[e-mail]>
+ * Author: Zhichang Yuan <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _ACPI_INDIRECT_PIO_H
+#define _ACPI_INDIRECT_PIO_H
+
+struct indirect_pio_device_desc {
+	void *pdata; /* device relevant info data */
+	int (*pre_setup)(struct acpi_device *adev, void *pdata);
+};
+
+int acpi_set_logic_pio_resource(struct device *child,
+		struct device *hostdev);
+
+#endif