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OMAP: omap_device: add omap_device_is_valid() 

The omap_device struct contains a 'struct platform_device'.  Normally,
converting a platform_device pointer to an omap_device pointer
consists of simply doing a container_of(), as is done currently by the
to_omap_device() macro.

However, if this is attempted when using platform_device that has not
been created as part of the omap_device creation, the container_of()
will point to a memory location before the platform_device pointer
which will contain random data.

Therefore, we need a way to detect valid omap_device pointers.  This
patch solves this by using the simple magic number approach.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
This commit is contained in:
Kevin Hilman 2010-02-24 12:05:45 -07:00 committed by Paul Walmsley
parent 80c20d543d
commit 0007122ad8
2 changed files with 18 additions and 0 deletions
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2
arch/arm/plat-omap/include/plat/omap_device.h
View File

@ -62,6 +62,7 @@
* *
*/ */
struct omap_device { struct omap_device {
u32 magic;
struct platform_device pdev; struct platform_device pdev;
struct omap_hwmod **hwmods; struct omap_hwmod **hwmods;
struct omap_device_pm_latency *pm_lats; struct omap_device_pm_latency *pm_lats;
@ -81,6 +82,7 @@ int omap_device_shutdown(struct platform_device *pdev);
/* Core code interface */ /* Core code interface */
bool omap_device_is_valid(struct omap_device *od);
int omap_device_count_resources(struct omap_device *od); int omap_device_count_resources(struct omap_device *od);
int omap_device_fill_resources(struct omap_device *od, struct resource *res); int omap_device_fill_resources(struct omap_device *od, struct resource *res);

16
arch/arm/plat-omap/omap_device.c
View File

@ -90,6 +90,8 @@
#define IGNORE_WAKEUP_LAT 1 #define IGNORE_WAKEUP_LAT 1
#define OMAP_DEVICE_MAGIC 0xf00dcafe
/* Private functions */ /* Private functions */
/** /**
@ -403,6 +405,8 @@ struct omap_device *omap_device_build_ss(const char *pdev_name, int pdev_id,
od->pm_lats = pm_lats; od->pm_lats = pm_lats;
od->pm_lats_cnt = pm_lats_cnt; od->pm_lats_cnt = pm_lats_cnt;
od->magic = OMAP_DEVICE_MAGIC;
ret = omap_device_register(od); ret = omap_device_register(od);
if (ret) if (ret)
goto odbs_exit4; goto odbs_exit4;
@ -588,6 +592,18 @@ int omap_device_align_pm_lat(struct platform_device *pdev,
return ret; return ret;
} }
/**
* omap_device_is_valid - Check if pointer is a valid omap_device
* @od: struct omap_device *
*
* Return whether struct omap_device pointer @od points to a valid
* omap_device.
*/
bool omap_device_is_valid(struct omap_device *od)
{
return (od && od->magic == OMAP_DEVICE_MAGIC);
}
/** /**
* omap_device_get_pwrdm - return the powerdomain * associated with @od * omap_device_get_pwrdm - return the powerdomain * associated with @od
* @od: struct omap_device * * @od: struct omap_device *