sysreset: Add a way to find the last reset

We have a method to return the last reset as a string for humans, but not
a method that allows it to be used programmatically. Add a new method that
returns the last reset as an enum.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/sysreset/sysreset-uclass.c

@@ -36,6 +36,16 @@ int sysreset_get_status(struct udevice *dev, char *buf, int size)
 	return ops->get_status(dev, buf, size);
 }
 
+int sysreset_get_last(struct udevice *dev)
+{
+	struct sysreset_ops *ops = sysreset_get_ops(dev);
+
+	if (!ops->get_last)
+		return -ENOSYS;
+
+	return ops->get_last(dev);
+}
+
 int sysreset_walk(enum sysreset_t type)
 {
 	struct udevice *dev;
@@ -55,6 +65,26 @@ int sysreset_walk(enum sysreset_t type)
 	return ret;
 }
 
+int sysreset_get_last_walk(void)
+{
+	struct udevice *dev;
+	int value = -ENOENT;
+
+	for (uclass_first_device(UCLASS_SYSRESET, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		int ret;
+
+		ret = sysreset_get_last(dev);
+		if (ret >= 0) {
+			value = ret;
+			break;
+		}
+	}
+
+	return value;
+}
+
 void sysreset_walk_halt(enum sysreset_t type)
 {
 	int ret;

drivers/sysreset/sysreset_sandbox.c

@@ -36,6 +36,11 @@ int sandbox_warm_sysreset_get_status(struct udevice *dev, char *buf, int size)
 	return 0;
 }
 
+int sandbox_warm_sysreset_get_last(struct udevice *dev)
+{
+	return SYSRESET_WARM;
+}
+
 static int sandbox_sysreset_request(struct udevice *dev, enum sysreset_t type)
 {
 	struct sandbox_state *state = state_get_current();
@@ -58,6 +63,9 @@ static int sandbox_sysreset_request(struct udevice *dev, enum sysreset_t type)
 			return -EACCES;
 		sandbox_exit();
 		break;
+	case SYSRESET_POWER_OFF:
+		if (!state->sysreset_allowed[type])
+			return -EACCES;
 	default:
 		return -ENOSYS;
 	}
@@ -74,9 +82,15 @@ int sandbox_sysreset_get_status(struct udevice *dev, char *buf, int size)
 	return 0;
 }
 
+int sandbox_sysreset_get_last(struct udevice *dev)
+{
+	return SYSRESET_COLD;
+}
+
 static struct sysreset_ops sandbox_sysreset_ops = {
 	.request	= sandbox_sysreset_request,
 	.get_status	= sandbox_sysreset_get_status,
+	.get_last	= sandbox_sysreset_get_last,
 };
 
 static const struct udevice_id sandbox_sysreset_ids[] = {
@@ -94,6 +108,7 @@ U_BOOT_DRIVER(sysreset_sandbox) = {
 static struct sysreset_ops sandbox_warm_sysreset_ops = {
 	.request	= sandbox_warm_sysreset_request,
 	.get_status	= sandbox_warm_sysreset_get_status,
+	.get_last	= sandbox_warm_sysreset_get_last,
 };
 
 static const struct udevice_id sandbox_warm_sysreset_ids[] = {