ARM: sunxi: Add sunxi restart function via onchip watchdog

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/arch/arm/mach-sunxi/sunxi.c b/arch/arm/mach-sunxi/sunxi.c
index 13d4d96cbc85..dc634ae2081f 100644
--- a/arch/arm/mach-sunxi/sunxi.c
+++ b/arch/arm/mach-sunxi/sunxi.c
@@ -12,6 +12,7 @@
 
 #include <linux/kernel.h>
 #include <linux/init.h>
+#include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/io.h>
@@ -26,6 +27,36 @@
 
 #include "sunxi.h"
 
+#define WATCHDOG_CTRL_REG       0x00
+#define WATCHDOG_MODE_REG       0x04
+
+static void __iomem *wdt_base;
+
+static void sunxi_setup_restart(void)
+{
+        struct device_node *np = of_find_compatible_node(NULL, NULL,
+                                                "allwinner,sunxi-wdt");
+        if (WARN(!np, "unable to setup watchdog restart"))
+                return;
+
+        wdt_base = of_iomap(np, 0);
+        WARN(!wdt_base, "failed to map watchdog base address");
+}
+
+static void sunxi_restart(char mode, const char *cmd)
+{
+        if (!wdt_base)
+                return;
+
+        /* Enable timer and set reset bit in the watchdog */
+        writel(3, wdt_base + WATCHDOG_MODE_REG);
+        writel(0xa57 << 1 | 1, wdt_base + WATCHDOG_CTRL_REG);
+        while(1) {
+                mdelay(5);
+                writel(3, wdt_base + WATCHDOG_MODE_REG);
+        }
+}
+
 static struct map_desc sunxi_io_desc[] __initdata = {
         {
                 .virtual        = (unsigned long) SUNXI_REGS_VIRT_BASE,
@@ -42,6 +73,8 @@ void __init sunxi_map_io(void)
 
 static void __init sunxi_dt_init(void)
 {
+        sunxi_setup_restart();
+
         of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
 }
 
@@ -56,6 +89,7 @@ DT_MACHINE_START(SUNXI_DT, "Allwinner A1X (Device Tree)")
         .map_io         = sunxi_map_io,
         .init_irq       = sunxi_init_irq,
         .handle_irq     = sunxi_handle_irq,
+        .restart        = sunxi_restart,
         .timer          = &sunxi_timer,
         .dt_compat      = sunxi_board_dt_compat,
 MACHINE_END