sysreset: Add get_status method

It's useful to have the reset status of the SoC printed out during reset
(e.g. to learn whether the reset was caused by software or a watchdog).

As a first step to implement this, add a get_status method to the
sysreset class, which enables the caller to get printable information
about the reset status (akin to get_desc in the CPU uclass).

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>

drivers/sysreset/sysreset-uclass.c

@@ -24,6 +24,16 @@ int sysreset_request(struct udevice *dev, enum sysreset_t type)
 	return ops->request(dev, type);
 }
 
+int sysreset_get_status(struct udevice *dev, char *buf, int size)
+{
+	struct sysreset_ops *ops = sysreset_get_ops(dev);
+
+	if (!ops->get_status)
+		return -ENOSYS;
+
+	return ops->get_status(dev, buf, size);
+}
+
 int sysreset_walk(enum sysreset_t type)
 {
 	struct udevice *dev;

include/sysreset.h

@@ -28,6 +28,14 @@ struct sysreset_ops {
 	 *		(in which case this method will not actually return)
 	 */
 	int (*request)(struct udevice *dev, enum sysreset_t type);
+	/**
+	 * get_status() - get printable reset status information
+	 *
+	 * @buf:	Buffer to receive the textual reset information
+	 * @size:	Size of the passed buffer
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_status)(struct udevice *dev, char *buf, int size);
 };
 
 #define sysreset_get_ops(dev)        ((struct sysreset_ops *)(dev)->driver->ops)
@@ -41,6 +49,15 @@ struct sysreset_ops {
 int sysreset_request(struct udevice *dev, enum sysreset_t type);
 
 /**
+ * get_status() - get printable reset status information
+ *
+ * @buf:	Buffer to receive the textual reset information
+ * @size:	Size of the passed buffer
+ * @return 0 if OK, -ve on error
+ */
+int sysreset_get_status(struct udevice *dev, char *buf, int size);
+
+/**
  * sysreset_walk() - cause a system reset
  *
  * This works through the available sysreset devices until it finds one that can