ARM: sun6i: Add restart code for the A31

The Allwinner A31 has a different watchdog, with a slightly different
register layout, that requires a different restart code.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

2 files changed, 43 insertions, 5 deletions

diff --git a/Documentation/devicetree/bindings/watchdog/sun4i-wdt.txt b/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt
index ecd650adff31..e39cb266c8f4 100644
--- a/Documentation/devicetree/bindings/watchdog/sun4i-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/sunxi-wdt.txt
@@ -1,8 +1,9 @@
-Allwinner sun4i Watchdog timer
+Allwinner SoCs Watchdog timer
 
 Required properties:
 
-- compatible : should be "allwinner,sun4i-wdt"
+- compatible : should be "allwinner,<soc-family>-wdt", the currently supported
+  SoC families being sun4i and sun6i
 - reg : Specifies base physical address and size of the registers.
 
 Example:
diff --git a/arch/arm/mach-sunxi/sunxi.c b/arch/arm/mach-sunxi/sunxi.c
index 11326d9f13da..223995e0481f 100644
--- a/arch/arm/mach-sunxi/sunxi.c
+++ b/arch/arm/mach-sunxi/sunxi.c
@@ -27,10 +27,19 @@
 #include <asm/system_misc.h>
 
 #define SUN4I_WATCHDOG_CTRL_REG         0x00
-#define SUN4I_WATCHDOG_CTRL_RESTART             (1 << 0)
+#define SUN4I_WATCHDOG_CTRL_RESTART             BIT(0)
 #define SUN4I_WATCHDOG_MODE_REG         0x04
-#define SUN4I_WATCHDOG_MODE_ENABLE              (1 << 0)
-#define SUN4I_WATCHDOG_MODE_RESET_ENABLE        (1 << 1)
+#define SUN4I_WATCHDOG_MODE_ENABLE              BIT(0)
+#define SUN4I_WATCHDOG_MODE_RESET_ENABLE        BIT(1)
+
+#define SUN6I_WATCHDOG1_IRQ_REG         0x00
+#define SUN6I_WATCHDOG1_CTRL_REG        0x10
+#define SUN6I_WATCHDOG1_CTRL_RESTART            BIT(0)
+#define SUN6I_WATCHDOG1_CONFIG_REG      0x14
+#define SUN6I_WATCHDOG1_CONFIG_RESTART          BIT(0)
+#define SUN6I_WATCHDOG1_CONFIG_IRQ              BIT(1)
+#define SUN6I_WATCHDOG1_MODE_REG        0x18
+#define SUN6I_WATCHDOG1_MODE_ENABLE             BIT(0)
 
 static void __iomem *wdt_base;
 
@@ -56,8 +65,36 @@ static void sun4i_restart(enum reboot_mode mode, const char *cmd)
         }
 }
 
+static void sun6i_restart(enum reboot_mode mode, const char *cmd)
+{
+        if (!wdt_base)
+                return;
+
+        /* Disable interrupts */
+        writel(0, wdt_base + SUN6I_WATCHDOG1_IRQ_REG);
+
+        /* We want to disable the IRQ and just reset the whole system */
+        writel(SUN6I_WATCHDOG1_CONFIG_RESTART,
+                wdt_base + SUN6I_WATCHDOG1_CONFIG_REG);
+
+        /* Enable timer. The default and lowest interval value is 0.5s */
+        writel(SUN6I_WATCHDOG1_MODE_ENABLE,
+                wdt_base + SUN6I_WATCHDOG1_MODE_REG);
+
+        /* Restart the watchdog. */
+        writel(SUN6I_WATCHDOG1_CTRL_RESTART,
+                wdt_base + SUN6I_WATCHDOG1_CTRL_REG);
+
+        while (1) {
+                mdelay(5);
+                writel(SUN6I_WATCHDOG1_MODE_ENABLE,
+                        wdt_base + SUN6I_WATCHDOG1_MODE_REG);
+        }
+}
+
 static struct of_device_id sunxi_restart_ids[] = {
         { .compatible = "allwinner,sun4i-wdt", .data = sun4i_restart },
+        { .compatible = "allwinner,sun6i-wdt", .data = sun6i_restart },
         { /*sentinel*/ }
 };