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>
diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index 5195dbb..40289e0 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 @@
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;
@@ -589,6 +593,18 @@
}
/**
+ * 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 *
*