power: reset: Add Allwinner A31 reset code

[karo-tx-linux.git] / drivers / power / reset / sun6i-reboot.c

diff --git a/drivers/power/reset/sun6i-reboot.c b/drivers/power/reset/sun6i-reboot.c
new file mode 100644 (file)
index 0000000..af2cd7f
--- /dev/null
+++ b/drivers/power/reset/sun6i-reboot.c
@@ -0,0 +1,85 @@
+/*
+ * Allwinner A31 SoCs reset code
+ *
+ * Copyright (C) 2012-2014 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+
+#include <asm/system_misc.h>
+
+#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;
+
+static void sun6i_wdt_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 int sun6i_reboot_probe(struct platform_device *pdev)
+{
+       wdt_base = of_iomap(pdev->dev.of_node, 0);
+       if (!wdt_base) {
+               WARN(1, "failed to map watchdog base address");
+               return -ENODEV;
+       }
+
+       arm_pm_restart = sun6i_wdt_restart;
+
+       return 0;
+}
+
+static struct of_device_id sun6i_reboot_of_match[] = {
+       { .compatible = "allwinner,sun6i-a31-wdt" },
+       {}
+};
+
+static struct platform_driver sun6i_reboot_driver = {
+       .probe = sun6i_reboot_probe,
+       .driver = {
+               .name = "sun6i-reboot",
+               .of_match_table = sun6i_reboot_of_match,
+       },
+};
+module_platform_driver(sun6i_reboot_driver);