From 0007122ad85cc36b1c18c0b59344093ca210d206 Mon Sep 17 00:00:00 2001 From: Kevin Hilman Date: Wed, 24 Feb 2010 12:05:45 -0700 Subject: [PATCH] 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 Signed-off-by: Paul Walmsley --- arch/arm/plat-omap/include/plat/omap_device.h | 2 ++ arch/arm/plat-omap/omap_device.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/arch/arm/plat-omap/include/plat/omap_device.h b/arch/arm/plat-omap/include/plat/omap_device.h index 76d49171fed9..4677ff7d3ab5 100644 --- a/arch/arm/plat-omap/include/plat/omap_device.h +++ b/arch/arm/plat-omap/include/plat/omap_device.h @@ -62,6 +62,7 @@ * */ struct omap_device { + u32 magic; struct platform_device pdev; struct omap_hwmod **hwmods; struct omap_device_pm_latency *pm_lats; @@ -81,6 +82,7 @@ int omap_device_shutdown(struct platform_device *pdev); /* Core code interface */ +bool omap_device_is_valid(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); diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c index 5195dbb1a397..40289e095fc6 100644 --- a/arch/arm/plat-omap/omap_device.c +++ b/arch/arm/plat-omap/omap_device.c @@ -90,6 +90,8 @@ #define IGNORE_WAKEUP_LAT 1 +#define OMAP_DEVICE_MAGIC 0xf00dcafe + /* 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_cnt = pm_lats_cnt; + od->magic = OMAP_DEVICE_MAGIC; + ret = omap_device_register(od); if (ret) goto odbs_exit4; @@ -588,6 +592,18 @@ int omap_device_align_pm_lat(struct platform_device *pdev, 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 * @od: struct omap_device * -- 2.39.2