linux/drivers/power/reset/sun6i-reboot.c

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/*
* 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);