| Message ID | 1399981716-24618-1-git-send-email-pawel.moll@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 13, 2014 at 6:48 AM, Pawel Moll <pawel.moll@arm.com> wrote: > In "Device Tree powered" systems, platform devices are usually > massively populated with of_platform_populate() call, executed > at some level of initcalls, either by generic architecture > or by platform-specific code. > > There are situations though where certain devices must be > created (and bound with drivers) before all the others. > This presents a challenge, as devices created explicitly > would be created again by of_platform_populate(). > > This patch tries to solve that issue in a generic way, > adding a "populated" flag for a DT node description. > Once set, this device will never be created again via > of_* API, so of_platform_populate() will skip such nodes > (and its children) in a similar way to the non-available > ones. > > The flag is cleared when a device is being removed and > returns the DT node by calling of_device_node_put() (it > was missing from the amba device release function, added). > > Signed-off-by: Pawel Moll <pawel.moll@arm.com> A few formatting nits, but otherwise: Reviewed-by: Rob Herring <robh@kernel.org> [..] > @@ -206,12 +206,13 @@ static struct platform_device *of_platform_device_create_pdata( > { > struct platform_device *dev; > > - if (!of_device_is_available(np)) > + if (!of_device_is_available(np) || > + of_node_test_and_set_flag(np, OF_POPULATED)) This should be lined up with the ! on the previous line. > @@ -264,14 +269,15 @@ static struct amba_device *of_amba_device_create(struct device_node *node, > > pr_debug("Creating amba device %s\n", node->full_name); > > - if (!of_device_is_available(node)) > + if (!of_device_is_available(node) || > + of_node_test_and_set_flag(node, OF_POPULATED)) And this one. > return NULL; Rob
On Tue, 13 May 2014 07:24:50 -0500, Rob Herring <robherring2@gmail.com> wrote: > On Tue, May 13, 2014 at 6:48 AM, Pawel Moll <pawel.moll@arm.com> wrote: > > In "Device Tree powered" systems, platform devices are usually > > massively populated with of_platform_populate() call, executed > > at some level of initcalls, either by generic architecture > > or by platform-specific code. > > > > There are situations though where certain devices must be > > created (and bound with drivers) before all the others. > > This presents a challenge, as devices created explicitly > > would be created again by of_platform_populate(). > > > > This patch tries to solve that issue in a generic way, > > adding a "populated" flag for a DT node description. > > Once set, this device will never be created again via > > of_* API, so of_platform_populate() will skip such nodes > > (and its children) in a similar way to the non-available > > ones. > > > > The flag is cleared when a device is being removed and > > returns the DT node by calling of_device_node_put() (it > > was missing from the amba device release function, added). > > > > Signed-off-by: Pawel Moll <pawel.moll@arm.com> > > A few formatting nits, but otherwise: > > Reviewed-by: Rob Herring <robh@kernel.org> Acked-by: Grant Likely <grant.likely@linaro.org> g.
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 3cf61a1..0f489fb 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -17,6 +17,7 @@ #include <linux/pm_runtime.h> #include <linux/amba/bus.h> #include <linux/sizes.h> +#include <linux/of_device.h> #include <asm/irq.h> @@ -268,6 +269,7 @@ static void amba_device_release(struct device *dev) { struct amba_device *d = to_amba_device(dev); + of_device_node_put(dev); if (d->res.parent) release_resource(&d->res); kfree(d); diff --git a/drivers/of/platform.c b/drivers/of/platform.c index bd47fbc..2d0c8b7 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -206,12 +206,13 @@ static struct platform_device *of_platform_device_create_pdata( { struct platform_device *dev; - if (!of_device_is_available(np)) + if (!of_device_is_available(np) || + of_node_test_and_set_flag(np, OF_POPULATED)) return NULL; dev = of_device_alloc(np, bus_id, parent); if (!dev) - return NULL; + goto err_clear_flag; #if defined(CONFIG_MICROBLAZE) dev->archdata.dma_mask = 0xffffffffUL; @@ -229,10 +230,14 @@ static struct platform_device *of_platform_device_create_pdata( if (of_device_add(dev) != 0) { platform_device_put(dev); - return NULL; + goto err_clear_flag; } return dev; + +err_clear_flag: + of_node_clear_flag(np, OF_POPULATED); + return NULL; } /** @@ -264,14 +269,15 @@ static struct amba_device *of_amba_device_create(struct device_node *node, pr_debug("Creating amba device %s\n", node->full_name); - if (!of_device_is_available(node)) + if (!of_device_is_available(node) || + of_node_test_and_set_flag(node, OF_POPULATED)) return NULL; dev = amba_device_alloc(NULL, 0, 0); if (!dev) { pr_err("%s(): amba_device_alloc() failed for %s\n", __func__, node->full_name); - return NULL; + goto err_clear_flag; } /* setup generic device info */ @@ -311,6 +317,8 @@ static struct amba_device *of_amba_device_create(struct device_node *node, err_free: amba_device_put(dev); +err_clear_flag: + of_node_clear_flag(node, OF_POPULATED); return NULL; } #else /* CONFIG_ARM_AMBA */ diff --git a/include/linux/of.h b/include/linux/of.h index 3bad8d1..3fd6079 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -130,6 +130,12 @@ static inline int of_node_check_flag(struct device_node *n, unsigned long flag) return test_bit(flag, &n->_flags); } +static inline int of_node_test_and_set_flag(struct device_node *n, + unsigned long flag) +{ + return test_and_set_bit(flag, &n->_flags); +} + static inline void of_node_set_flag(struct device_node *n, unsigned long flag) { set_bit(flag, &n->_flags); @@ -197,6 +203,7 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size) /* flag descriptions */ #define OF_DYNAMIC 1 /* node and properties were allocated via kmalloc */ #define OF_DETACHED 2 /* node has been detached from the device tree */ +#define OF_POPULATED 3 /* device already created for the node */ #define OF_IS_DYNAMIC(x) test_bit(OF_DYNAMIC, &x->_flags) #define OF_MARK_DYNAMIC(x) set_bit(OF_DYNAMIC, &x->_flags) diff --git a/include/linux/of_device.h b/include/linux/of_device.h index ef37021..fd14d46 100644 --- a/include/linux/of_device.h +++ b/include/linux/of_device.h @@ -41,6 +41,8 @@ extern int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env static inline void of_device_node_put(struct device *dev) { + if (dev->of_node) + of_node_clear_flag(dev->of_node, OF_POPULATED); of_node_put(dev->of_node); }
In "Device Tree powered" systems, platform devices are usually massively populated with of_platform_populate() call, executed at some level of initcalls, either by generic architecture or by platform-specific code. There are situations though where certain devices must be created (and bound with drivers) before all the others. This presents a challenge, as devices created explicitly would be created again by of_platform_populate(). This patch tries to solve that issue in a generic way, adding a "populated" flag for a DT node description. Once set, this device will never be created again via of_* API, so of_platform_populate() will skip such nodes (and its children) in a similar way to the non-available ones. The flag is cleared when a device is being removed and returns the DT node by calling of_device_node_put() (it was missing from the amba device release function, added). Signed-off-by: Pawel Moll <pawel.moll@arm.com> --- Changes since v2: - the populated flag is now cleared when the device is being removed by platform or amba bus code - added missing of_device_node_put() to amba_device_release() - renamed of_node_check_and_set_flag() to of_node_check_test_and_set_flag() to follow the bitops naming convention - didn't add Rob's ack as the patch changed too much Changes since v1: - added of_node_check_and_set_flag()... (atomic test and set) - ... used it to atomically mark a node... - ... clearing the bit on error path. drivers/amba/bus.c | 2 ++ drivers/of/platform.c | 18 +++++++++++++----- include/linux/of.h | 7 +++++++ include/linux/of_device.h | 2 ++ 4 files changed, 24 insertions(+), 5 deletions(-)