drivers/watchdog/mtk_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Mediatek Watchdog Driver
  *
  * Copyright (C) 2014 Matthias Brugger
  *
  * Matthias Brugger <matthias.bgg@gmail.com>
  *
  * Based on sunxi_wdt.c
  */

 #include <dt-bindings/reset-controller/mt2712-resets.h>
 #include <dt-bindings/reset-controller/mt8183-resets.h>
 #include <dt-bindings/reset-controller/mt8192-resets.h>
 #include <dt-bindings/reset/mt8195-resets.h>
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/reset-controller.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/interrupt.h>

 #define WDT_MAX_TIMEOUT		31
 #define WDT_MIN_TIMEOUT		2
 #define WDT_LENGTH_TIMEOUT(n)	((n) << 5)

 #define WDT_LENGTH		0x04
 #define WDT_LENGTH_KEY		0x8

 #define WDT_RST			0x08
 #define WDT_RST_RELOAD		0x1971

 #define WDT_MODE		0x00
 #define WDT_MODE_EN		(1 << 0)
 #define WDT_MODE_EXT_POL_LOW	(0 << 1)
 #define WDT_MODE_EXT_POL_HIGH	(1 << 1)
 #define WDT_MODE_EXRST_EN	(1 << 2)
 #define WDT_MODE_IRQ_EN		(1 << 3)
 #define WDT_MODE_AUTO_START	(1 << 4)
 #define WDT_MODE_DUAL_EN	(1 << 6)
 #define WDT_MODE_KEY		0x22000000

 #define WDT_SWRST		0x14
 #define WDT_SWRST_KEY		0x1209

 #define WDT_SWSYSRST		0x18U
 #define WDT_SWSYS_RST_KEY	0x88000000

 #define DRV_NAME		"mtk-wdt"
 #define DRV_VERSION		"1.0"

 static bool nowayout = WATCHDOG_NOWAYOUT;
 static unsigned int timeout;

 struct mtk_wdt_dev {
 	struct watchdog_device wdt_dev;
 	void __iomem *wdt_base;
 	spinlock_t lock; /* protects WDT_SWSYSRST reg */
 	struct reset_controller_dev rcdev;
 };

 struct mtk_wdt_data {
 	int toprgu_sw_rst_num;
 };

 static const struct mtk_wdt_data mt2712_data = {
 	.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
 };

 static const struct mtk_wdt_data mt8183_data = {
 	.toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
 };

 static const struct mtk_wdt_data mt8192_data = {
 	.toprgu_sw_rst_num = MT8192_TOPRGU_SW_RST_NUM,
 };

 static const struct mtk_wdt_data mt8195_data = {
 	.toprgu_sw_rst_num = MT8195_TOPRGU_SW_RST_NUM,
 };

 static int toprgu_reset_update(struct reset_controller_dev *rcdev,
 			       unsigned long id, bool assert)
 {
 	unsigned int tmp;
 	unsigned long flags;
 	struct mtk_wdt_dev *data =
 		 container_of(rcdev, struct mtk_wdt_dev, rcdev);

 	spin_lock_irqsave(&data->lock, flags);

 	tmp = readl(data->wdt_base + WDT_SWSYSRST);
 	if (assert)
 		tmp |= BIT(id);
 	else
 		tmp &= ~BIT(id);
 	tmp |= WDT_SWSYS_RST_KEY;
 	writel(tmp, data->wdt_base + WDT_SWSYSRST);

 	spin_unlock_irqrestore(&data->lock, flags);

 	return 0;
 }

 static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
 			       unsigned long id)
 {
 	return toprgu_reset_update(rcdev, id, true);
 }

 static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
 				 unsigned long id)
 {
 	return toprgu_reset_update(rcdev, id, false);
 }

 static int toprgu_reset(struct reset_controller_dev *rcdev,
 			unsigned long id)
 {
 	int ret;

 	ret = toprgu_reset_assert(rcdev, id);
 	if (ret)
 		return ret;

 	return toprgu_reset_deassert(rcdev, id);
 }

 static const struct reset_control_ops toprgu_reset_ops = {
 	.assert = toprgu_reset_assert,
 	.deassert = toprgu_reset_deassert,
 	.reset = toprgu_reset,
 };

 static int toprgu_register_reset_controller(struct platform_device *pdev,
 					    int rst_num)
 {
 	int ret;
 	struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);

 	spin_lock_init(&mtk_wdt->lock);

 	mtk_wdt->rcdev.owner = THIS_MODULE;
 	mtk_wdt->rcdev.nr_resets = rst_num;
 	mtk_wdt->rcdev.ops = &toprgu_reset_ops;
 	mtk_wdt->rcdev.of_node = pdev->dev.of_node;
 	ret = devm_reset_controller_register(&pdev->dev, &mtk_wdt->rcdev);
 	if (ret != 0)
 		dev_err(&pdev->dev,
 			"couldn't register wdt reset controller: %d\n", ret);
 	return ret;
 }

 static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
 			   unsigned long action, void *data)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base;

 	wdt_base = mtk_wdt->wdt_base;

 	while (1) {
 		writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
 		mdelay(5);
 	}

 	return 0;
 }

 static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;

 	iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);

 	return 0;
 }

 static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
 				unsigned int timeout)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;
 	u32 reg;

 	wdt_dev->timeout = timeout;
 	/*
 	 * In dual mode, irq will be triggered at timeout / 2
 	 * the real timeout occurs at timeout
 	 */
 	if (wdt_dev->pretimeout)
 		wdt_dev->pretimeout = timeout / 2;

 	/*
 	 * One bit is the value of 512 ticks
 	 * The clock has 32 KHz
 	 */
 	reg = WDT_LENGTH_TIMEOUT((timeout - wdt_dev->pretimeout) << 6)
 			| WDT_LENGTH_KEY;
 	iowrite32(reg, wdt_base + WDT_LENGTH);

 	mtk_wdt_ping(wdt_dev);

 	return 0;
 }

 static void mtk_wdt_init(struct watchdog_device *wdt_dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base;

 	wdt_base = mtk_wdt->wdt_base;

 	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
 		set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
 		mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 	}
 }

 static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;
 	u32 reg;

 	reg = readl(wdt_base + WDT_MODE);
 	reg &= ~WDT_MODE_EN;
 	reg |= WDT_MODE_KEY;
 	iowrite32(reg, wdt_base + WDT_MODE);

 	return 0;
 }

 static int mtk_wdt_start(struct watchdog_device *wdt_dev)
 {
 	u32 reg;
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;
 	int ret;

 	ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 	if (ret < 0)
 		return ret;

 	reg = ioread32(wdt_base + WDT_MODE);
 	if (wdt_dev->pretimeout)
 		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	else
 		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	reg |= (WDT_MODE_EN | WDT_MODE_KEY);
 	iowrite32(reg, wdt_base + WDT_MODE);

 	return 0;
 }

 static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
 				  unsigned int timeout)
 {
 	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd);
 	void __iomem *wdt_base = mtk_wdt->wdt_base;
 	u32 reg = ioread32(wdt_base + WDT_MODE);

 	if (timeout && !wdd->pretimeout) {
 		wdd->pretimeout = wdd->timeout / 2;
 		reg |= (WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	} else if (!timeout && wdd->pretimeout) {
 		wdd->pretimeout = 0;
 		reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
 	} else {
 		return 0;
 	}

 	reg |= WDT_MODE_KEY;
 	iowrite32(reg, wdt_base + WDT_MODE);

 	return mtk_wdt_set_timeout(wdd, wdd->timeout);
 }

 static irqreturn_t mtk_wdt_isr(int irq, void *arg)
 {
 	struct watchdog_device *wdd = arg;

 	watchdog_notify_pretimeout(wdd);

 	return IRQ_HANDLED;
 }

 static const struct watchdog_info mtk_wdt_info = {
 	.identity	= DRV_NAME,
 	.options	= WDIOF_SETTIMEOUT |
 			  WDIOF_KEEPALIVEPING |
 			  WDIOF_MAGICCLOSE,
 };

 static const struct watchdog_info mtk_wdt_pt_info = {
 	.identity	= DRV_NAME,
 	.options	= WDIOF_SETTIMEOUT |
 			  WDIOF_PRETIMEOUT |
 			  WDIOF_KEEPALIVEPING |
 			  WDIOF_MAGICCLOSE,
 };

 static const struct watchdog_ops mtk_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= mtk_wdt_start,
 	.stop		= mtk_wdt_stop,
 	.ping		= mtk_wdt_ping,
 	.set_timeout	= mtk_wdt_set_timeout,
 	.set_pretimeout	= mtk_wdt_set_pretimeout,
 	.restart	= mtk_wdt_restart,
 };

 static int mtk_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct mtk_wdt_dev *mtk_wdt;
 	const struct mtk_wdt_data *wdt_data;
 	int err, irq;

 	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
 	if (!mtk_wdt)
 		return -ENOMEM;

 	platform_set_drvdata(pdev, mtk_wdt);

 	mtk_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mtk_wdt->wdt_base))
 		return PTR_ERR(mtk_wdt->wdt_base);

 	irq = platform_get_irq(pdev, 0);
 	if (irq > 0) {
 		err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
 				       &mtk_wdt->wdt_dev);
 		if (err)
 			return err;

 		mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
 		mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT / 2;
 	} else {
 		if (irq == -EPROBE_DEFER)
 			return -EPROBE_DEFER;

 		mtk_wdt->wdt_dev.info = &mtk_wdt_info;
 	}

 	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
 	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
 	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
 	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
 	mtk_wdt->wdt_dev.parent = dev;

 	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
 	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
 	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);

 	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);

 	mtk_wdt_init(&mtk_wdt->wdt_dev);

 	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
 	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
 	if (unlikely(err))
 		return err;

 	dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
 		 mtk_wdt->wdt_dev.timeout, nowayout);

 	wdt_data = of_device_get_match_data(dev);
 	if (wdt_data) {
 		err = toprgu_register_reset_controller(pdev,
 						       wdt_data->toprgu_sw_rst_num);
 		if (err)
 			return err;
 	}
 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int mtk_wdt_suspend(struct device *dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);

 	if (watchdog_active(&mtk_wdt->wdt_dev))
 		mtk_wdt_stop(&mtk_wdt->wdt_dev);

 	return 0;
 }

 static int mtk_wdt_resume(struct device *dev)
 {
 	struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);

 	if (watchdog_active(&mtk_wdt->wdt_dev)) {
 		mtk_wdt_start(&mtk_wdt->wdt_dev);
 		mtk_wdt_ping(&mtk_wdt->wdt_dev);
 	}

 	return 0;
 }
 #endif

 static const struct of_device_id mtk_wdt_dt_ids[] = {
 	{ .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
 	{ .compatible = "mediatek,mt6589-wdt" },
 	{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
 	{ .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
 	{ .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);

 static const struct dev_pm_ops mtk_wdt_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend,
 				mtk_wdt_resume)
 };

 static struct platform_driver mtk_wdt_driver = {
 	.probe		= mtk_wdt_probe,
 	.driver		= {
 		.name		= DRV_NAME,
 		.pm		= &mtk_wdt_pm_ops,
 		.of_match_table	= mtk_wdt_dt_ids,
 	},
 };

 module_platform_driver(mtk_wdt_driver);

 module_param(timeout, uint, 0);
 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");

 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
 MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
 MODULE_VERSION(DRV_VERSION);
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Mediatek Watchdog Driver
	*
	* Copyright (C) 2014 Matthias Brugger
	*
	* Matthias Brugger <matthias.bgg@gmail.com>
	*
	* Based on sunxi_wdt.c
	*/

	#include <dt-bindings/reset-controller/mt2712-resets.h>
	#include <dt-bindings/reset-controller/mt8183-resets.h>
	#include <dt-bindings/reset-controller/mt8192-resets.h>
	#include <dt-bindings/reset/mt8195-resets.h>
	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>
	#include <linux/reset-controller.h>
	#include <linux/types.h>
	#include <linux/watchdog.h>
	#include <linux/interrupt.h>

	#define WDT_MAX_TIMEOUT 31
	#define WDT_MIN_TIMEOUT 2
	#define WDT_LENGTH_TIMEOUT(n) ((n) << 5)

	#define WDT_LENGTH 0x04
	#define WDT_LENGTH_KEY 0x8

	#define WDT_RST 0x08
	#define WDT_RST_RELOAD 0x1971

	#define WDT_MODE 0x00
	#define WDT_MODE_EN (1 << 0)
	#define WDT_MODE_EXT_POL_LOW (0 << 1)
	#define WDT_MODE_EXT_POL_HIGH (1 << 1)
	#define WDT_MODE_EXRST_EN (1 << 2)
	#define WDT_MODE_IRQ_EN (1 << 3)
	#define WDT_MODE_AUTO_START (1 << 4)
	#define WDT_MODE_DUAL_EN (1 << 6)
	#define WDT_MODE_KEY 0x22000000

	#define WDT_SWRST 0x14
	#define WDT_SWRST_KEY 0x1209

	#define WDT_SWSYSRST 0x18U
	#define WDT_SWSYS_RST_KEY 0x88000000

	#define DRV_NAME "mtk-wdt"
	#define DRV_VERSION "1.0"

	static bool nowayout = WATCHDOG_NOWAYOUT;
	static unsigned int timeout;

	struct mtk_wdt_dev {
	struct watchdog_device wdt_dev;
	void __iomem *wdt_base;
	spinlock_t lock; /* protects WDT_SWSYSRST reg */
	struct reset_controller_dev rcdev;
	};

	struct mtk_wdt_data {
	int toprgu_sw_rst_num;
	};

	static const struct mtk_wdt_data mt2712_data = {
	.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
	};

	static const struct mtk_wdt_data mt8183_data = {
	.toprgu_sw_rst_num = MT8183_TOPRGU_SW_RST_NUM,
	};

	static const struct mtk_wdt_data mt8192_data = {
	.toprgu_sw_rst_num = MT8192_TOPRGU_SW_RST_NUM,
	};

	static const struct mtk_wdt_data mt8195_data = {
	.toprgu_sw_rst_num = MT8195_TOPRGU_SW_RST_NUM,
	};

	static int toprgu_reset_update(struct reset_controller_dev *rcdev,
	unsigned long id, bool assert)
	{
	unsigned int tmp;
	unsigned long flags;
	struct mtk_wdt_dev *data =
	container_of(rcdev, struct mtk_wdt_dev, rcdev);

	spin_lock_irqsave(&data->lock, flags);

	tmp = readl(data->wdt_base + WDT_SWSYSRST);
	if (assert)
	tmp \|= BIT(id);
	else
	tmp &= ~BIT(id);
	tmp \|= WDT_SWSYS_RST_KEY;
	writel(tmp, data->wdt_base + WDT_SWSYSRST);

	spin_unlock_irqrestore(&data->lock, flags);

	return 0;
	}

	static int toprgu_reset_assert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	return toprgu_reset_update(rcdev, id, true);
	}

	static int toprgu_reset_deassert(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	return toprgu_reset_update(rcdev, id, false);
	}

	static int toprgu_reset(struct reset_controller_dev *rcdev,
	unsigned long id)
	{
	int ret;

	ret = toprgu_reset_assert(rcdev, id);
	if (ret)
	return ret;

	return toprgu_reset_deassert(rcdev, id);
	}

	static const struct reset_control_ops toprgu_reset_ops = {
	.assert = toprgu_reset_assert,
	.deassert = toprgu_reset_deassert,
	.reset = toprgu_reset,
	};

	static int toprgu_register_reset_controller(struct platform_device *pdev,
	int rst_num)
	{
	int ret;
	struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);

	spin_lock_init(&mtk_wdt->lock);

	mtk_wdt->rcdev.owner = THIS_MODULE;
	mtk_wdt->rcdev.nr_resets = rst_num;
	mtk_wdt->rcdev.ops = &toprgu_reset_ops;
	mtk_wdt->rcdev.of_node = pdev->dev.of_node;
	ret = devm_reset_controller_register(&pdev->dev, &mtk_wdt->rcdev);
	if (ret != 0)
	dev_err(&pdev->dev,
	"couldn't register wdt reset controller: %d\n", ret);
	return ret;
	}

	static int mtk_wdt_restart(struct watchdog_device *wdt_dev,
	unsigned long action, void *data)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base;

	wdt_base = mtk_wdt->wdt_base;

	while (1) {
	writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
	mdelay(5);
	}

	return 0;
	}

	static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base = mtk_wdt->wdt_base;

	iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);

	return 0;
	}

	static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
	unsigned int timeout)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base = mtk_wdt->wdt_base;
	u32 reg;

	wdt_dev->timeout = timeout;
	/*
	* In dual mode, irq will be triggered at timeout / 2
	* the real timeout occurs at timeout
	*/
	if (wdt_dev->pretimeout)
	wdt_dev->pretimeout = timeout / 2;

	/*
	* One bit is the value of 512 ticks
	* The clock has 32 KHz
	*/
	reg = WDT_LENGTH_TIMEOUT((timeout - wdt_dev->pretimeout) << 6)
	\| WDT_LENGTH_KEY;
	iowrite32(reg, wdt_base + WDT_LENGTH);

	mtk_wdt_ping(wdt_dev);

	return 0;
	}

	static void mtk_wdt_init(struct watchdog_device *wdt_dev)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base;

	wdt_base = mtk_wdt->wdt_base;

	if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) {
	set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
	mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
	}
	}

	static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base = mtk_wdt->wdt_base;
	u32 reg;

	reg = readl(wdt_base + WDT_MODE);
	reg &= ~WDT_MODE_EN;
	reg \|= WDT_MODE_KEY;
	iowrite32(reg, wdt_base + WDT_MODE);

	return 0;
	}

	static int mtk_wdt_start(struct watchdog_device *wdt_dev)
	{
	u32 reg;
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
	void __iomem *wdt_base = mtk_wdt->wdt_base;
	int ret;

	ret = mtk_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
	if (ret < 0)
	return ret;

	reg = ioread32(wdt_base + WDT_MODE);
	if (wdt_dev->pretimeout)
	reg \|= (WDT_MODE_IRQ_EN \| WDT_MODE_DUAL_EN);
	else
	reg &= ~(WDT_MODE_IRQ_EN \| WDT_MODE_DUAL_EN);
	reg \|= (WDT_MODE_EN \| WDT_MODE_KEY);
	iowrite32(reg, wdt_base + WDT_MODE);

	return 0;
	}

	static int mtk_wdt_set_pretimeout(struct watchdog_device *wdd,
	unsigned int timeout)
	{
	struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdd);
	void __iomem *wdt_base = mtk_wdt->wdt_base;
	u32 reg = ioread32(wdt_base + WDT_MODE);

	if (timeout && !wdd->pretimeout) {
	wdd->pretimeout = wdd->timeout / 2;
	reg \|= (WDT_MODE_IRQ_EN \| WDT_MODE_DUAL_EN);
	} else if (!timeout && wdd->pretimeout) {
	wdd->pretimeout = 0;
	reg &= ~(WDT_MODE_IRQ_EN \| WDT_MODE_DUAL_EN);
	} else {
	return 0;
	}

	reg \|= WDT_MODE_KEY;
	iowrite32(reg, wdt_base + WDT_MODE);

	return mtk_wdt_set_timeout(wdd, wdd->timeout);
	}

	static irqreturn_t mtk_wdt_isr(int irq, void *arg)
	{
	struct watchdog_device *wdd = arg;

	watchdog_notify_pretimeout(wdd);

	return IRQ_HANDLED;
	}

	static const struct watchdog_info mtk_wdt_info = {
	.identity = DRV_NAME,
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};

	static const struct watchdog_info mtk_wdt_pt_info = {
	.identity = DRV_NAME,
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_PRETIMEOUT \|
	WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE,
	};

	static const struct watchdog_ops mtk_wdt_ops = {
	.owner = THIS_MODULE,
	.start = mtk_wdt_start,
	.stop = mtk_wdt_stop,
	.ping = mtk_wdt_ping,
	.set_timeout = mtk_wdt_set_timeout,
	.set_pretimeout = mtk_wdt_set_pretimeout,
	.restart = mtk_wdt_restart,
	};

	static int mtk_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct mtk_wdt_dev *mtk_wdt;
	const struct mtk_wdt_data *wdt_data;
	int err, irq;

	mtk_wdt = devm_kzalloc(dev, sizeof(*mtk_wdt), GFP_KERNEL);
	if (!mtk_wdt)
	return -ENOMEM;

	platform_set_drvdata(pdev, mtk_wdt);

	mtk_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(mtk_wdt->wdt_base))
	return PTR_ERR(mtk_wdt->wdt_base);

	irq = platform_get_irq(pdev, 0);
	if (irq > 0) {
	err = devm_request_irq(&pdev->dev, irq, mtk_wdt_isr, 0, "wdt_bark",
	&mtk_wdt->wdt_dev);
	if (err)
	return err;

	mtk_wdt->wdt_dev.info = &mtk_wdt_pt_info;
	mtk_wdt->wdt_dev.pretimeout = WDT_MAX_TIMEOUT / 2;
	} else {
	if (irq == -EPROBE_DEFER)
	return -EPROBE_DEFER;

	mtk_wdt->wdt_dev.info = &mtk_wdt_info;
	}

	mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
	mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
	mtk_wdt->wdt_dev.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT * 1000;
	mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
	mtk_wdt->wdt_dev.parent = dev;

	watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, dev);
	watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
	watchdog_set_restart_priority(&mtk_wdt->wdt_dev, 128);

	watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);

	mtk_wdt_init(&mtk_wdt->wdt_dev);

	watchdog_stop_on_reboot(&mtk_wdt->wdt_dev);
	err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
	if (unlikely(err))
	return err;

	dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)\n",
	mtk_wdt->wdt_dev.timeout, nowayout);

	wdt_data = of_device_get_match_data(dev);
	if (wdt_data) {
	err = toprgu_register_reset_controller(pdev,
	wdt_data->toprgu_sw_rst_num);
	if (err)
	return err;
	}
	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int mtk_wdt_suspend(struct device *dev)
	{
	struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);

	if (watchdog_active(&mtk_wdt->wdt_dev))
	mtk_wdt_stop(&mtk_wdt->wdt_dev);

	return 0;
	}

	static int mtk_wdt_resume(struct device *dev)
	{
	struct mtk_wdt_dev *mtk_wdt = dev_get_drvdata(dev);

	if (watchdog_active(&mtk_wdt->wdt_dev)) {
	mtk_wdt_start(&mtk_wdt->wdt_dev);
	mtk_wdt_ping(&mtk_wdt->wdt_dev);
	}

	return 0;
	}
	#endif

	static const struct of_device_id mtk_wdt_dt_ids[] = {
	{ .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
	{ .compatible = "mediatek,mt6589-wdt" },
	{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
	{ .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
	{ .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);

	static const struct dev_pm_ops mtk_wdt_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(mtk_wdt_suspend,
	mtk_wdt_resume)
	};

	static struct platform_driver mtk_wdt_driver = {
	.probe = mtk_wdt_probe,
	.driver = {
	.name = DRV_NAME,
	.pm = &mtk_wdt_pm_ops,
	.of_match_table = mtk_wdt_dt_ids,
	},
	};

	module_platform_driver(mtk_wdt_driver);

	module_param(timeout, uint, 0);
	MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");

	module_param(nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Matthias Brugger <matthias.bgg@gmail.com>");
	MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
	MODULE_VERSION(DRV_VERSION);