dm: sysreset: add watchdog-reboot driver

Add a new sysreset driver that uses the recently added watchdog support.
It performs a full SoC reset by calling wdt_expire_now op.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/sysreset/Kconfig

@@ -31,4 +31,10 @@ config SYSRESET_SYSCON
 	help
 	  Reboot support for generic SYSCON mapped register reset.
 
+config SYSRESET_WATCHDOG
+	bool "Enable support for watchdog reboot driver"
+	select WDT
+	help
+	  Reboot support for generic watchdog reset.
+
 endmenu

drivers/sysreset/Makefile

@@ -7,6 +7,7 @@
 obj-$(CONFIG_SYSRESET) += sysreset-uclass.o
 obj-$(CONFIG_SYSRESET_PSCI) += sysreset_psci.o
 obj-$(CONFIG_SYSRESET_SYSCON) += sysreset_syscon.o
+obj-$(CONFIG_SYSRESET_WATCHDOG) += sysreset_watchdog.o
 
 ifndef CONFIG_SPL_BUILD
 obj-$(CONFIG_ROCKCHIP_RK3036) += sysreset_rk3036.o

drivers/sysreset/sysreset_watchdog.c

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <sysreset.h>
+#include <wdt.h>
+
+struct wdt_reboot_priv {
+	struct udevice *wdt;
+};
+
+static int wdt_reboot_request(struct udevice *dev, enum sysreset_t type)
+{
+	struct wdt_reboot_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = wdt_expire_now(priv->wdt, 0);
+	if (ret)
+		return ret;
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops wdt_reboot_ops = {
+	.request = wdt_reboot_request,
+};
+
+int wdt_reboot_probe(struct udevice *dev)
+{
+	struct wdt_reboot_priv *priv = dev_get_priv(dev);
+	int err;
+
+	err = uclass_get_device_by_phandle(UCLASS_WDT, dev,
+					   "wdt", &priv->wdt);
+	if (err) {
+		error("unable to find wdt device\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id wdt_reboot_ids[] = {
+	{ .compatible = "wdt-reboot" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(wdt_reboot) = {
+	.name = "wdt_reboot",
+	.id = UCLASS_SYSRESET,
+	.of_match = wdt_reboot_ids,
+	.ops = &wdt_reboot_ops,
+	.priv_auto_alloc_size = sizeof(struct wdt_reboot_priv),
+	.probe = wdt_reboot_probe,
+};