drivers/watchdog/uniphier_wdt.c - kernel/common - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Watchdog driver for the UniPhier watchdog timer
  *
  * (c) Copyright 2014 Panasonic Corporation
  * (c) Copyright 2016 Socionext Inc.
  * All rights reserved.
  */

 #include <linux/bitops.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 #include <linux/watchdog.h>

 /* WDT timer setting register */
 #define WDTTIMSET			0x3004
 #define   WDTTIMSET_PERIOD_MASK		(0xf << 0)
 #define   WDTTIMSET_PERIOD_1_SEC	(0x3 << 0)

 /* WDT reset selection register */
 #define WDTRSTSEL			0x3008
 #define   WDTRSTSEL_RSTSEL_MASK		(0x3 << 0)
 #define   WDTRSTSEL_RSTSEL_BOTH		(0x0 << 0)
 #define   WDTRSTSEL_RSTSEL_IRQ_ONLY	(0x2 << 0)

 /* WDT control register */
 #define WDTCTRL				0x300c
 #define   WDTCTRL_STATUS		BIT(8)
 #define   WDTCTRL_CLEAR			BIT(1)
 #define   WDTCTRL_ENABLE		BIT(0)

 #define SEC_TO_WDTTIMSET_PRD(sec) \
 		(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)

 #define WDTST_TIMEOUT			1000 /* usec */

 #define WDT_DEFAULT_TIMEOUT		64   /* Default is 64 seconds */
 #define WDT_PERIOD_MIN			1
 #define WDT_PERIOD_MAX			128

 static unsigned int timeout = 0;
 static bool nowayout = WATCHDOG_NOWAYOUT;

 struct uniphier_wdt_dev {
 	struct watchdog_device wdt_dev;
 	struct regmap	*regmap;
 };

 /*
  * UniPhier Watchdog operations
  */
 static int uniphier_watchdog_ping(struct watchdog_device *w)
 {
 	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 	unsigned int val;
 	int ret;

 	/* Clear counter */
 	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
 				WDTCTRL_CLEAR, WDTCTRL_CLEAR);
 	if (!ret)
 		/*
 		 * As SoC specification, after clear counter,
 		 * it needs to wait until counter status is 1.
 		 */
 		ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
 					       (val & WDTCTRL_STATUS),
 					       0, WDTST_TIMEOUT);

 	return ret;
 }

 static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
 {
 	unsigned int val;
 	int ret;

 	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
 				       !(val & WDTCTRL_STATUS),
 				       0, WDTST_TIMEOUT);
 	if (ret)
 		return ret;

 	/* Setup period */
 	ret = regmap_write(regmap, WDTTIMSET,
 			   SEC_TO_WDTTIMSET_PRD(sec));
 	if (ret)
 		return ret;

 	/* Enable and clear watchdog */
 	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
 	if (!ret)
 		/*
 		 * As SoC specification, after clear counter,
 		 * it needs to wait until counter status is 1.
 		 */
 		ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
 					       (val & WDTCTRL_STATUS),
 					       0, WDTST_TIMEOUT);

 	return ret;
 }

 static int __uniphier_watchdog_stop(struct regmap *regmap)
 {
 	/* Disable and stop watchdog */
 	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
 }

 static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
 {
 	int ret;

 	ret = __uniphier_watchdog_stop(regmap);
 	if (ret)
 		return ret;

 	return __uniphier_watchdog_start(regmap, sec);
 }

 static int uniphier_watchdog_start(struct watchdog_device *w)
 {
 	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 	unsigned int tmp_timeout;

 	tmp_timeout = roundup_pow_of_two(w->timeout);

 	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
 }

 static int uniphier_watchdog_stop(struct watchdog_device *w)
 {
 	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);

 	return __uniphier_watchdog_stop(wdev->regmap);
 }

 static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
 					 unsigned int t)
 {
 	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 	unsigned int tmp_timeout;
 	int ret;

 	tmp_timeout = roundup_pow_of_two(t);
 	if (tmp_timeout == w->timeout)
 		return 0;

 	if (watchdog_active(w)) {
 		ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
 		if (ret)
 			return ret;
 	}

 	w->timeout = tmp_timeout;

 	return 0;
 }

 /*
  * Kernel Interfaces
  */
 static const struct watchdog_info uniphier_wdt_info = {
 	.identity	= "uniphier-wdt",
 	.options	= WDIOF_SETTIMEOUT |
 			  WDIOF_KEEPALIVEPING |
 			  WDIOF_MAGICCLOSE |
 			  WDIOF_OVERHEAT,
 };

 static const struct watchdog_ops uniphier_wdt_ops = {
 	.owner		= THIS_MODULE,
 	.start		= uniphier_watchdog_start,
 	.stop		= uniphier_watchdog_stop,
 	.ping		= uniphier_watchdog_ping,
 	.set_timeout	= uniphier_watchdog_set_timeout,
 };

 static int uniphier_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct uniphier_wdt_dev *wdev;
 	struct regmap *regmap;
 	struct device_node *parent;
 	int ret;

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

 	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
 	regmap = syscon_node_to_regmap(parent);
 	of_node_put(parent);
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);

 	wdev->regmap = regmap;
 	wdev->wdt_dev.info = &uniphier_wdt_info;
 	wdev->wdt_dev.ops = &uniphier_wdt_ops;
 	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
 	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
 	wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
 	wdev->wdt_dev.parent = dev;

 	watchdog_init_timeout(&wdev->wdt_dev, timeout, dev);
 	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
 	watchdog_stop_on_reboot(&wdev->wdt_dev);

 	watchdog_set_drvdata(&wdev->wdt_dev, wdev);

 	uniphier_watchdog_stop(&wdev->wdt_dev);
 	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
 	if (ret)
 		return ret;

 	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
 	if (ret)
 		return ret;

 	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
 		 wdev->wdt_dev.timeout, nowayout);

 	return 0;
 }

 static const struct of_device_id uniphier_wdt_dt_ids[] = {
 	{ .compatible = "socionext,uniphier-wdt" },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);

 static struct platform_driver uniphier_wdt_driver = {
 	.probe		= uniphier_wdt_probe,
 	.driver		= {
 		.name		= "uniphier-wdt",
 		.of_match_table	= uniphier_wdt_dt_ids,
 	},
 };

 module_platform_driver(uniphier_wdt_driver);

 module_param(timeout, uint, 0000);
 MODULE_PARM_DESC(timeout,
 	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
 				__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

 module_param(nowayout, bool, 0000);
 MODULE_PARM_DESC(nowayout,
 	"Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 MODULE_AUTHOR("Keiji Hayashibara <[email protected]>");
 MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Watchdog driver for the UniPhier watchdog timer
	*
	* (c) Copyright 2014 Panasonic Corporation
	* (c) Copyright 2016 Socionext Inc.
	* All rights reserved.
	*/

	#include <linux/bitops.h>
	#include <linux/mfd/syscon.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/regmap.h>
	#include <linux/watchdog.h>

	/* WDT timer setting register */
	#define WDTTIMSET 0x3004
	#define WDTTIMSET_PERIOD_MASK (0xf << 0)
	#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0)

	/* WDT reset selection register */
	#define WDTRSTSEL 0x3008
	#define WDTRSTSEL_RSTSEL_MASK (0x3 << 0)
	#define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0)
	#define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0)

	/* WDT control register */
	#define WDTCTRL 0x300c
	#define WDTCTRL_STATUS BIT(8)
	#define WDTCTRL_CLEAR BIT(1)
	#define WDTCTRL_ENABLE BIT(0)

	#define SEC_TO_WDTTIMSET_PRD(sec) \
	(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)

	#define WDTST_TIMEOUT 1000 /* usec */

	#define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */
	#define WDT_PERIOD_MIN 1
	#define WDT_PERIOD_MAX 128

	static unsigned int timeout = 0;
	static bool nowayout = WATCHDOG_NOWAYOUT;

	struct uniphier_wdt_dev {
	struct watchdog_device wdt_dev;
	struct regmap *regmap;
	};

	/*
	* UniPhier Watchdog operations
	*/
	static int uniphier_watchdog_ping(struct watchdog_device *w)
	{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int val;
	int ret;

	/* Clear counter */
	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
	WDTCTRL_CLEAR, WDTCTRL_CLEAR);
	if (!ret)
	/*
	* As SoC specification, after clear counter,
	* it needs to wait until counter status is 1.
	*/
	ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
	(val & WDTCTRL_STATUS),
	0, WDTST_TIMEOUT);

	return ret;
	}

	static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
	{
	unsigned int val;
	int ret;

	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
	!(val & WDTCTRL_STATUS),
	0, WDTST_TIMEOUT);
	if (ret)
	return ret;

	/* Setup period */
	ret = regmap_write(regmap, WDTTIMSET,
	SEC_TO_WDTTIMSET_PRD(sec));
	if (ret)
	return ret;

	/* Enable and clear watchdog */
	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE \| WDTCTRL_CLEAR);
	if (!ret)
	/*
	* As SoC specification, after clear counter,
	* it needs to wait until counter status is 1.
	*/
	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
	(val & WDTCTRL_STATUS),
	0, WDTST_TIMEOUT);

	return ret;
	}

	static int __uniphier_watchdog_stop(struct regmap *regmap)
	{
	/* Disable and stop watchdog */
	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
	}

	static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
	{
	int ret;

	ret = __uniphier_watchdog_stop(regmap);
	if (ret)
	return ret;

	return __uniphier_watchdog_start(regmap, sec);
	}

	static int uniphier_watchdog_start(struct watchdog_device *w)
	{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int tmp_timeout;

	tmp_timeout = roundup_pow_of_two(w->timeout);

	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
	}

	static int uniphier_watchdog_stop(struct watchdog_device *w)
	{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);

	return __uniphier_watchdog_stop(wdev->regmap);
	}

	static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
	unsigned int t)
	{
	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
	unsigned int tmp_timeout;
	int ret;

	tmp_timeout = roundup_pow_of_two(t);
	if (tmp_timeout == w->timeout)
	return 0;

	if (watchdog_active(w)) {
	ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
	if (ret)
	return ret;
	}

	w->timeout = tmp_timeout;

	return 0;
	}

	/*
	* Kernel Interfaces
	*/
	static const struct watchdog_info uniphier_wdt_info = {
	.identity = "uniphier-wdt",
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_KEEPALIVEPING \|
	WDIOF_MAGICCLOSE \|
	WDIOF_OVERHEAT,
	};

	static const struct watchdog_ops uniphier_wdt_ops = {
	.owner = THIS_MODULE,
	.start = uniphier_watchdog_start,
	.stop = uniphier_watchdog_stop,
	.ping = uniphier_watchdog_ping,
	.set_timeout = uniphier_watchdog_set_timeout,
	};

	static int uniphier_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct uniphier_wdt_dev *wdev;
	struct regmap *regmap;
	struct device_node *parent;
	int ret;

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

	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
	regmap = syscon_node_to_regmap(parent);
	of_node_put(parent);
	if (IS_ERR(regmap))
	return PTR_ERR(regmap);

	wdev->regmap = regmap;
	wdev->wdt_dev.info = &uniphier_wdt_info;
	wdev->wdt_dev.ops = &uniphier_wdt_ops;
	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
	wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
	wdev->wdt_dev.parent = dev;

	watchdog_init_timeout(&wdev->wdt_dev, timeout, dev);
	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
	watchdog_stop_on_reboot(&wdev->wdt_dev);

	watchdog_set_drvdata(&wdev->wdt_dev, wdev);

	uniphier_watchdog_stop(&wdev->wdt_dev);
	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
	if (ret)
	return ret;

	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
	if (ret)
	return ret;

	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
	wdev->wdt_dev.timeout, nowayout);

	return 0;
	}

	static const struct of_device_id uniphier_wdt_dt_ids[] = {
	{ .compatible = "socionext,uniphier-wdt" },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);

	static struct platform_driver uniphier_wdt_driver = {
	.probe = uniphier_wdt_probe,
	.driver = {
	.name = "uniphier-wdt",
	.of_match_table = uniphier_wdt_dt_ids,
	},
	};

	module_platform_driver(uniphier_wdt_driver);

	module_param(timeout, uint, 0000);
	MODULE_PARM_DESC(timeout,
	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
	__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

	module_param(nowayout, bool, 0000);
	MODULE_PARM_DESC(nowayout,
	"Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	MODULE_AUTHOR("Keiji Hayashibara <[email protected]>");
	MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
	MODULE_LICENSE("GPL v2");