drivers/watchdog/sama5d4_wdt.c - kernel/msm-5.4 - Gitiles

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Driver for Atmel SAMA5D4 Watchdog Timer
  *
  * Copyright (C) 2015 Atmel Corporation
  */

 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/reboot.h>
 #include <linux/watchdog.h>

 #include "at91sam9_wdt.h"

 /* minimum and maximum watchdog timeout, in seconds */
 #define MIN_WDT_TIMEOUT		1
 #define MAX_WDT_TIMEOUT		16
 #define WDT_DEFAULT_TIMEOUT	MAX_WDT_TIMEOUT

 #define WDT_SEC2TICKS(s)	((s) ? (((s) << 8) - 1) : 0)

 struct sama5d4_wdt {
 	struct watchdog_device	wdd;
 	void __iomem		*reg_base;
 	u32			mr;
 	unsigned long		last_ping;
 };

 static int wdt_timeout;
 static bool nowayout = WATCHDOG_NOWAYOUT;

 module_param(wdt_timeout, int, 0);
 MODULE_PARM_DESC(wdt_timeout,
 	"Watchdog timeout in seconds. (default = "
 	__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

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

 #define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS))

 #define wdt_read(wdt, field) \
 	readl_relaxed((wdt)->reg_base + (field))

 /* 4 slow clock periods is 4/32768 = 122.07µs*/
 #define WDT_DELAY	usecs_to_jiffies(123)

 static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
 {
 	/*
 	 * WDT_CR and WDT_MR must not be modified within three slow clock
 	 * periods following a restart of the watchdog performed by a write
 	 * access in WDT_CR.
 	 */
 	while (time_before(jiffies, wdt->last_ping + WDT_DELAY))
 		usleep_range(30, 125);
 	writel_relaxed(val, wdt->reg_base + field);
 	wdt->last_ping = jiffies;
 }

 static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val)
 {
 	if (time_before(jiffies, wdt->last_ping + WDT_DELAY))
 		udelay(123);
 	writel_relaxed(val, wdt->reg_base + field);
 	wdt->last_ping = jiffies;
 }

 static int sama5d4_wdt_start(struct watchdog_device *wdd)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt->mr &= ~AT91_WDT_WDDIS;
 	wdt_write(wdt, AT91_WDT_MR, wdt->mr);

 	return 0;
 }

 static int sama5d4_wdt_stop(struct watchdog_device *wdd)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt->mr |= AT91_WDT_WDDIS;
 	wdt_write(wdt, AT91_WDT_MR, wdt->mr);

 	return 0;
 }

 static int sama5d4_wdt_ping(struct watchdog_device *wdd)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);

 	return 0;
 }

 static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
 				 unsigned int timeout)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
 	u32 value = WDT_SEC2TICKS(timeout);

 	wdt->mr &= ~AT91_WDT_WDV;
 	wdt->mr &= ~AT91_WDT_WDD;
 	wdt->mr |= AT91_WDT_SET_WDV(value);
 	wdt->mr |= AT91_WDT_SET_WDD(value);

 	/*
 	 * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When
 	 * setting the WDDIS bit, and while it is set, the fields WDV and WDD
 	 * must not be modified.
 	 * If the watchdog is enabled, then the timeout can be updated. Else,
 	 * wait that the user enables it.
 	 */
 	if (wdt_enabled)
 		wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);

 	wdd->timeout = timeout;

 	return 0;
 }

 static const struct watchdog_info sama5d4_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 	.identity = "Atmel SAMA5D4 Watchdog",
 };

 static const struct watchdog_ops sama5d4_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = sama5d4_wdt_start,
 	.stop = sama5d4_wdt_stop,
 	.ping = sama5d4_wdt_ping,
 	.set_timeout = sama5d4_wdt_set_timeout,
 };

 static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
 {
 	struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);

 	if (wdt_read(wdt, AT91_WDT_SR)) {
 		pr_crit("Atmel Watchdog Software Reset\n");
 		emergency_restart();
 		pr_crit("Reboot didn't succeed\n");
 	}

 	return IRQ_HANDLED;
 }

 static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
 {
 	const char *tmp;

 	wdt->mr = AT91_WDT_WDDIS;

 	if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
 	    !strcmp(tmp, "software"))
 		wdt->mr |= AT91_WDT_WDFIEN;
 	else
 		wdt->mr |= AT91_WDT_WDRSTEN;

 	if (of_property_read_bool(np, "atmel,idle-halt"))
 		wdt->mr |= AT91_WDT_WDIDLEHLT;

 	if (of_property_read_bool(np, "atmel,dbg-halt"))
 		wdt->mr |= AT91_WDT_WDDBGHLT;

 	return 0;
 }

 static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
 {
 	u32 reg;
 	/*
 	 * When booting and resuming, the bootloader may have changed the
 	 * watchdog configuration.
 	 * If the watchdog is already running, we can safely update it.
 	 * Else, we have to disable it properly.
 	 */
 	if (wdt_enabled) {
 		wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
 	} else {
 		reg = wdt_read(wdt, AT91_WDT_MR);
 		if (!(reg & AT91_WDT_WDDIS))
 			wdt_write_nosleep(wdt, AT91_WDT_MR,
 					  reg | AT91_WDT_WDDIS);
 	}
 	return 0;
 }

 static int sama5d4_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct watchdog_device *wdd;
 	struct sama5d4_wdt *wdt;
 	void __iomem *regs;
 	u32 irq = 0;
 	u32 timeout;
 	int ret;

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

 	wdd = &wdt->wdd;
 	wdd->timeout = WDT_DEFAULT_TIMEOUT;
 	wdd->info = &sama5d4_wdt_info;
 	wdd->ops = &sama5d4_wdt_ops;
 	wdd->min_timeout = MIN_WDT_TIMEOUT;
 	wdd->max_timeout = MAX_WDT_TIMEOUT;
 	wdt->last_ping = jiffies;

 	watchdog_set_drvdata(wdd, wdt);

 	regs = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(regs))
 		return PTR_ERR(regs);

 	wdt->reg_base = regs;

 	irq = irq_of_parse_and_map(dev->of_node, 0);
 	if (!irq)
 		dev_warn(dev, "failed to get IRQ from DT\n");

 	ret = of_sama5d4_wdt_init(dev->of_node, wdt);
 	if (ret)
 		return ret;

 	if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
 		ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
 				       IRQF_SHARED | IRQF_IRQPOLL |
 				       IRQF_NO_SUSPEND, pdev->name, pdev);
 		if (ret) {
 			dev_err(dev, "cannot register interrupt handler\n");
 			return ret;
 		}
 	}

 	watchdog_init_timeout(wdd, wdt_timeout, dev);

 	timeout = WDT_SEC2TICKS(wdd->timeout);

 	wdt->mr |= AT91_WDT_SET_WDD(timeout);
 	wdt->mr |= AT91_WDT_SET_WDV(timeout);

 	ret = sama5d4_wdt_init(wdt);
 	if (ret)
 		return ret;

 	watchdog_set_nowayout(wdd, nowayout);

 	watchdog_stop_on_unregister(wdd);
 	ret = devm_watchdog_register_device(dev, wdd);
 	if (ret) {
 		dev_err(dev, "failed to register watchdog device\n");
 		return ret;
 	}

 	platform_set_drvdata(pdev, wdt);

 	dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n",
 		 wdd->timeout, nowayout);

 	return 0;
 }

 static const struct of_device_id sama5d4_wdt_of_match[] = {
 	{ .compatible = "atmel,sama5d4-wdt", },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);

 #ifdef CONFIG_PM_SLEEP
 static int sama5d4_wdt_resume(struct device *dev)
 {
 	struct sama5d4_wdt *wdt = dev_get_drvdata(dev);

 	/*
 	 * FIXME: writing MR also pings the watchdog which may not be desired.
 	 * This should only be done when the registers are lost on suspend but
 	 * there is no way to get this information right now.
 	 */
 	sama5d4_wdt_init(wdt);

 	return 0;
 }
 #endif

 static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL,
 			 sama5d4_wdt_resume);

 static struct platform_driver sama5d4_wdt_driver = {
 	.probe		= sama5d4_wdt_probe,
 	.driver		= {
 		.name	= "sama5d4_wdt",
 		.pm	= &sama5d4_wdt_pm_ops,
 		.of_match_table = sama5d4_wdt_of_match,
 	}
 };
 module_platform_driver(sama5d4_wdt_driver);

 MODULE_AUTHOR("Atmel Corporation");
 MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Driver for Atmel SAMA5D4 Watchdog Timer
	*
	* Copyright (C) 2015 Atmel Corporation
	*/

	#include <linux/delay.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_irq.h>
	#include <linux/platform_device.h>
	#include <linux/reboot.h>
	#include <linux/watchdog.h>

	#include "at91sam9_wdt.h"

	/* minimum and maximum watchdog timeout, in seconds */
	#define MIN_WDT_TIMEOUT 1
	#define MAX_WDT_TIMEOUT 16
	#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT

	#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)

	struct sama5d4_wdt {
	struct watchdog_device wdd;
	void __iomem *reg_base;
	u32 mr;
	unsigned long last_ping;
	};

	static int wdt_timeout;
	static bool nowayout = WATCHDOG_NOWAYOUT;

	module_param(wdt_timeout, int, 0);
	MODULE_PARM_DESC(wdt_timeout,
	"Watchdog timeout in seconds. (default = "
	__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

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

	#define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS))

	#define wdt_read(wdt, field) \
	readl_relaxed((wdt)->reg_base + (field))

	/* 4 slow clock periods is 4/32768 = 122.07µs*/
	#define WDT_DELAY usecs_to_jiffies(123)

	static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
	{
	/*
	* WDT_CR and WDT_MR must not be modified within three slow clock
	* periods following a restart of the watchdog performed by a write
	* access in WDT_CR.
	*/
	while (time_before(jiffies, wdt->last_ping + WDT_DELAY))
	usleep_range(30, 125);
	writel_relaxed(val, wdt->reg_base + field);
	wdt->last_ping = jiffies;
	}

	static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val)
	{
	if (time_before(jiffies, wdt->last_ping + WDT_DELAY))
	udelay(123);
	writel_relaxed(val, wdt->reg_base + field);
	wdt->last_ping = jiffies;
	}

	static int sama5d4_wdt_start(struct watchdog_device *wdd)
	{
	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->mr &= ~AT91_WDT_WDDIS;
	wdt_write(wdt, AT91_WDT_MR, wdt->mr);

	return 0;
	}

	static int sama5d4_wdt_stop(struct watchdog_device *wdd)
	{
	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->mr \|= AT91_WDT_WDDIS;
	wdt_write(wdt, AT91_WDT_MR, wdt->mr);

	return 0;
	}

	static int sama5d4_wdt_ping(struct watchdog_device *wdd)
	{
	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY \| AT91_WDT_WDRSTT);

	return 0;
	}

	static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
	unsigned int timeout)
	{
	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
	u32 value = WDT_SEC2TICKS(timeout);

	wdt->mr &= ~AT91_WDT_WDV;
	wdt->mr &= ~AT91_WDT_WDD;
	wdt->mr \|= AT91_WDT_SET_WDV(value);
	wdt->mr \|= AT91_WDT_SET_WDD(value);

	/*
	* WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When
	* setting the WDDIS bit, and while it is set, the fields WDV and WDD
	* must not be modified.
	* If the watchdog is enabled, then the timeout can be updated. Else,
	* wait that the user enables it.
	*/
	if (wdt_enabled)
	wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);

	wdd->timeout = timeout;

	return 0;
	}

	static const struct watchdog_info sama5d4_wdt_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING,
	.identity = "Atmel SAMA5D4 Watchdog",
	};

	static const struct watchdog_ops sama5d4_wdt_ops = {
	.owner = THIS_MODULE,
	.start = sama5d4_wdt_start,
	.stop = sama5d4_wdt_stop,
	.ping = sama5d4_wdt_ping,
	.set_timeout = sama5d4_wdt_set_timeout,
	};

	static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
	{
	struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);

	if (wdt_read(wdt, AT91_WDT_SR)) {
	pr_crit("Atmel Watchdog Software Reset\n");
	emergency_restart();
	pr_crit("Reboot didn't succeed\n");
	}

	return IRQ_HANDLED;
	}

	static int of_sama5d4_wdt_init(struct device_node np, struct sama5d4_wdt wdt)
	{
	const char *tmp;

	wdt->mr = AT91_WDT_WDDIS;

	if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
	!strcmp(tmp, "software"))
	wdt->mr \|= AT91_WDT_WDFIEN;
	else
	wdt->mr \|= AT91_WDT_WDRSTEN;

	if (of_property_read_bool(np, "atmel,idle-halt"))
	wdt->mr \|= AT91_WDT_WDIDLEHLT;

	if (of_property_read_bool(np, "atmel,dbg-halt"))
	wdt->mr \|= AT91_WDT_WDDBGHLT;

	return 0;
	}

	static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
	{
	u32 reg;
	/*
	* When booting and resuming, the bootloader may have changed the
	* watchdog configuration.
	* If the watchdog is already running, we can safely update it.
	* Else, we have to disable it properly.
	*/
	if (wdt_enabled) {
	wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
	} else {
	reg = wdt_read(wdt, AT91_WDT_MR);
	if (!(reg & AT91_WDT_WDDIS))
	wdt_write_nosleep(wdt, AT91_WDT_MR,
	reg \| AT91_WDT_WDDIS);
	}
	return 0;
	}

	static int sama5d4_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct watchdog_device *wdd;
	struct sama5d4_wdt *wdt;
	void __iomem *regs;
	u32 irq = 0;
	u32 timeout;
	int ret;

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

	wdd = &wdt->wdd;
	wdd->timeout = WDT_DEFAULT_TIMEOUT;
	wdd->info = &sama5d4_wdt_info;
	wdd->ops = &sama5d4_wdt_ops;
	wdd->min_timeout = MIN_WDT_TIMEOUT;
	wdd->max_timeout = MAX_WDT_TIMEOUT;
	wdt->last_ping = jiffies;

	watchdog_set_drvdata(wdd, wdt);

	regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(regs))
	return PTR_ERR(regs);

	wdt->reg_base = regs;

	irq = irq_of_parse_and_map(dev->of_node, 0);
	if (!irq)
	dev_warn(dev, "failed to get IRQ from DT\n");

	ret = of_sama5d4_wdt_init(dev->of_node, wdt);
	if (ret)
	return ret;

	if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
	ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
	IRQF_SHARED \| IRQF_IRQPOLL \|
	IRQF_NO_SUSPEND, pdev->name, pdev);
	if (ret) {
	dev_err(dev, "cannot register interrupt handler\n");
	return ret;
	}
	}

	watchdog_init_timeout(wdd, wdt_timeout, dev);

	timeout = WDT_SEC2TICKS(wdd->timeout);

	wdt->mr \|= AT91_WDT_SET_WDD(timeout);
	wdt->mr \|= AT91_WDT_SET_WDV(timeout);

	ret = sama5d4_wdt_init(wdt);
	if (ret)
	return ret;

	watchdog_set_nowayout(wdd, nowayout);

	watchdog_stop_on_unregister(wdd);
	ret = devm_watchdog_register_device(dev, wdd);
	if (ret) {
	dev_err(dev, "failed to register watchdog device\n");
	return ret;
	}

	platform_set_drvdata(pdev, wdt);

	dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n",
	wdd->timeout, nowayout);

	return 0;
	}

	static const struct of_device_id sama5d4_wdt_of_match[] = {
	{ .compatible = "atmel,sama5d4-wdt", },
	{ }
	};
	MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);

	#ifdef CONFIG_PM_SLEEP
	static int sama5d4_wdt_resume(struct device *dev)
	{
	struct sama5d4_wdt *wdt = dev_get_drvdata(dev);

	/*
	* FIXME: writing MR also pings the watchdog which may not be desired.
	* This should only be done when the registers are lost on suspend but
	* there is no way to get this information right now.
	*/
	sama5d4_wdt_init(wdt);

	return 0;
	}
	#endif

	static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops, NULL,
	sama5d4_wdt_resume);

	static struct platform_driver sama5d4_wdt_driver = {
	.probe = sama5d4_wdt_probe,
	.driver = {
	.name = "sama5d4_wdt",
	.pm = &sama5d4_wdt_pm_ops,
	.of_match_table = sama5d4_wdt_of_match,
	}
	};
	module_platform_driver(sama5d4_wdt_driver);

	MODULE_AUTHOR("Atmel Corporation");
	MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
	MODULE_LICENSE("GPL v2");