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

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Watchdog driver for Renesas WDT watchdog
  *
  * Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
  * Copyright (C) 2015-17 Renesas Electronics Corporation
  */
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/smp.h>
 #include <linux/sys_soc.h>
 #include <linux/watchdog.h>

 #define RWTCNT		0
 #define RWTCSRA		4
 #define RWTCSRA_WOVF	BIT(4)
 #define RWTCSRA_WRFLG	BIT(5)
 #define RWTCSRA_TME	BIT(7)
 #define RWTCSRB		8

 #define RWDT_DEFAULT_TIMEOUT 60U

 /*
  * In probe, clk_rate is checked to be not more than 16 bit * biggest clock
  * divider (12 bits). d is only a factor to fully utilize the WDT counter and
  * will not exceed its 16 bits. Thus, no overflow, we stay below 32 bits.
  */
 #define MUL_BY_CLKS_PER_SEC(p, d) \
 	DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks])

 /* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */
 #define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate)

 static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024, 4096 };

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

 struct rwdt_priv {
 	void __iomem *base;
 	struct watchdog_device wdev;
 	unsigned long clk_rate;
 	u8 cks;
 };

 static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg)
 {
 	if (reg == RWTCNT)
 		val |= 0x5a5a0000;
 	else
 		val |= 0xa5a5a500;

 	writel_relaxed(val, priv->base + reg);
 }

 static int rwdt_init_timeout(struct watchdog_device *wdev)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

 	rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT);

 	return 0;
 }

 static int rwdt_start(struct watchdog_device *wdev)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
 	u8 val;

 	pm_runtime_get_sync(wdev->parent);

 	/* Stop the timer before we modify any register */
 	val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
 	rwdt_write(priv, val, RWTCSRA);

 	rwdt_init_timeout(wdev);
 	rwdt_write(priv, priv->cks, RWTCSRA);
 	rwdt_write(priv, 0, RWTCSRB);

 	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
 		cpu_relax();

 	rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA);

 	return 0;
 }

 static int rwdt_stop(struct watchdog_device *wdev)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

 	rwdt_write(priv, priv->cks, RWTCSRA);
 	pm_runtime_put(wdev->parent);

 	return 0;
 }

 static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
 	u16 val = readw_relaxed(priv->base + RWTCNT);

 	return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);
 }

 static int rwdt_restart(struct watchdog_device *wdev, unsigned long action,
 			void *data)
 {
 	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

 	rwdt_start(wdev);
 	rwdt_write(priv, 0xffff, RWTCNT);
 	return 0;
 }

 static const struct watchdog_info rwdt_ident = {
 	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
 		WDIOF_CARDRESET,
 	.identity = "Renesas WDT Watchdog",
 };

 static const struct watchdog_ops rwdt_ops = {
 	.owner = THIS_MODULE,
 	.start = rwdt_start,
 	.stop = rwdt_stop,
 	.ping = rwdt_init_timeout,
 	.get_timeleft = rwdt_get_timeleft,
 	.restart = rwdt_restart,
 };

 #if defined(CONFIG_ARCH_RCAR_GEN2) && defined(CONFIG_SMP)
 /*
  * Watchdog-reset integration is broken on early revisions of R-Car Gen2 SoCs
  */
 static const struct soc_device_attribute rwdt_quirks_match[] = {
 	{
 		.soc_id = "r8a7790",
 		.revision = "ES1.*",
 		.data = (void *)1,	/* needs single CPU */
 	}, {
 		.soc_id = "r8a7791",
 		.revision = "ES1.*",
 		.data = (void *)1,	/* needs single CPU */
 	}, {
 		.soc_id = "r8a7792",
 		.revision = "*",
 		.data = (void *)0,	/* needs SMP disabled */
 	},
 	{ /* sentinel */ }
 };

 static bool rwdt_blacklisted(struct device *dev)
 {
 	const struct soc_device_attribute *attr;

 	attr = soc_device_match(rwdt_quirks_match);
 	if (attr && setup_max_cpus > (uintptr_t)attr->data) {
 		dev_info(dev, "Watchdog blacklisted on %s %s\n", attr->soc_id,
 			 attr->revision);
 		return true;
 	}

 	return false;
 }
 #else /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */
 static inline bool rwdt_blacklisted(struct device *dev) { return false; }
 #endif /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */

 static int rwdt_probe(struct platform_device *pdev)
 {
 	struct rwdt_priv *priv;
 	struct clk *clk;
 	unsigned long clks_per_sec;
 	int ret, i;

 	if (rwdt_blacklisted(&pdev->dev))
 		return -ENODEV;

 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);

 	clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);

 	pm_runtime_enable(&pdev->dev);
 	pm_runtime_get_sync(&pdev->dev);
 	priv->clk_rate = clk_get_rate(clk);
 	priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) &
 				RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0;
 	pm_runtime_put(&pdev->dev);

 	if (!priv->clk_rate) {
 		ret = -ENOENT;
 		goto out_pm_disable;
 	}

 	for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
 		clks_per_sec = priv->clk_rate / clk_divs[i];
 		if (clks_per_sec && clks_per_sec < 65536) {
 			priv->cks = i;
 			break;
 		}
 	}

 	if (i < 0) {
 		dev_err(&pdev->dev, "Can't find suitable clock divider\n");
 		ret = -ERANGE;
 		goto out_pm_disable;
 	}

 	priv->wdev.info = &rwdt_ident;
 	priv->wdev.ops = &rwdt_ops;
 	priv->wdev.parent = &pdev->dev;
 	priv->wdev.min_timeout = 1;
 	priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536);
 	priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT);

 	platform_set_drvdata(pdev, priv);
 	watchdog_set_drvdata(&priv->wdev, priv);
 	watchdog_set_nowayout(&priv->wdev, nowayout);
 	watchdog_set_restart_priority(&priv->wdev, 0);
 	watchdog_stop_on_unregister(&priv->wdev);

 	/* This overrides the default timeout only if DT configuration was found */
 	ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
 	if (ret)
 		dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n");

 	ret = watchdog_register_device(&priv->wdev);
 	if (ret < 0)
 		goto out_pm_disable;

 	return 0;

  out_pm_disable:
 	pm_runtime_disable(&pdev->dev);
 	return ret;
 }

 static int rwdt_remove(struct platform_device *pdev)
 {
 	struct rwdt_priv *priv = platform_get_drvdata(pdev);

 	watchdog_unregister_device(&priv->wdev);
 	pm_runtime_disable(&pdev->dev);

 	return 0;
 }

 static int __maybe_unused rwdt_suspend(struct device *dev)
 {
 	struct rwdt_priv *priv = dev_get_drvdata(dev);

 	if (watchdog_active(&priv->wdev))
 		rwdt_stop(&priv->wdev);

 	return 0;
 }

 static int __maybe_unused rwdt_resume(struct device *dev)
 {
 	struct rwdt_priv *priv = dev_get_drvdata(dev);

 	if (watchdog_active(&priv->wdev))
 		rwdt_start(&priv->wdev);

 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume);

 static const struct of_device_id rwdt_ids[] = {
 	{ .compatible = "renesas,rcar-gen2-wdt", },
 	{ .compatible = "renesas,rcar-gen3-wdt", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rwdt_ids);

 static struct platform_driver rwdt_driver = {
 	.driver = {
 		.name = "renesas_wdt",
 		.of_match_table = rwdt_ids,
 		.pm = &rwdt_pm_ops,
 	},
 	.probe = rwdt_probe,
 	.remove = rwdt_remove,
 };
 module_platform_driver(rwdt_driver);

 MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Watchdog driver for Renesas WDT watchdog
	*
	* Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
	* Copyright (C) 2015-17 Renesas Electronics Corporation
	*/
	#include <linux/bitops.h>
	#include <linux/clk.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/smp.h>
	#include <linux/sys_soc.h>
	#include <linux/watchdog.h>

	#define RWTCNT 0
	#define RWTCSRA 4
	#define RWTCSRA_WOVF BIT(4)
	#define RWTCSRA_WRFLG BIT(5)
	#define RWTCSRA_TME BIT(7)
	#define RWTCSRB 8

	#define RWDT_DEFAULT_TIMEOUT 60U

	/*
	* In probe, clk_rate is checked to be not more than 16 bit * biggest clock
	* divider (12 bits). d is only a factor to fully utilize the WDT counter and
	* will not exceed its 16 bits. Thus, no overflow, we stay below 32 bits.
	*/
	#define MUL_BY_CLKS_PER_SEC(p, d) \
	DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks])

	/* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */
	#define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate)

	static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024, 4096 };

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

	struct rwdt_priv {
	void __iomem *base;
	struct watchdog_device wdev;
	unsigned long clk_rate;
	u8 cks;
	};

	static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg)
	{
	if (reg == RWTCNT)
	val \|= 0x5a5a0000;
	else
	val \|= 0xa5a5a500;

	writel_relaxed(val, priv->base + reg);
	}

	static int rwdt_init_timeout(struct watchdog_device *wdev)
	{
	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

	rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT);

	return 0;
	}

	static int rwdt_start(struct watchdog_device *wdev)
	{
	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
	u8 val;

	pm_runtime_get_sync(wdev->parent);

	/* Stop the timer before we modify any register */
	val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
	rwdt_write(priv, val, RWTCSRA);

	rwdt_init_timeout(wdev);
	rwdt_write(priv, priv->cks, RWTCSRA);
	rwdt_write(priv, 0, RWTCSRB);

	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
	cpu_relax();

	rwdt_write(priv, priv->cks \| RWTCSRA_TME, RWTCSRA);

	return 0;
	}

	static int rwdt_stop(struct watchdog_device *wdev)
	{
	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

	rwdt_write(priv, priv->cks, RWTCSRA);
	pm_runtime_put(wdev->parent);

	return 0;
	}

	static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
	{
	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
	u16 val = readw_relaxed(priv->base + RWTCNT);

	return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);
	}

	static int rwdt_restart(struct watchdog_device *wdev, unsigned long action,
	void *data)
	{
	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

	rwdt_start(wdev);
	rwdt_write(priv, 0xffff, RWTCNT);
	return 0;
	}

	static const struct watchdog_info rwdt_ident = {
	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \|
	WDIOF_CARDRESET,
	.identity = "Renesas WDT Watchdog",
	};

	static const struct watchdog_ops rwdt_ops = {
	.owner = THIS_MODULE,
	.start = rwdt_start,
	.stop = rwdt_stop,
	.ping = rwdt_init_timeout,
	.get_timeleft = rwdt_get_timeleft,
	.restart = rwdt_restart,
	};

	#if defined(CONFIG_ARCH_RCAR_GEN2) && defined(CONFIG_SMP)
	/*
	* Watchdog-reset integration is broken on early revisions of R-Car Gen2 SoCs
	*/
	static const struct soc_device_attribute rwdt_quirks_match[] = {
	{
	.soc_id = "r8a7790",
	.revision = "ES1.*",
	.data = (void )1, / needs single CPU */
	}, {
	.soc_id = "r8a7791",
	.revision = "ES1.*",
	.data = (void )1, / needs single CPU */
	}, {
	.soc_id = "r8a7792",
	.revision = "*",
	.data = (void )0, / needs SMP disabled */
	},
	{ /* sentinel */ }
	};

	static bool rwdt_blacklisted(struct device *dev)
	{
	const struct soc_device_attribute *attr;

	attr = soc_device_match(rwdt_quirks_match);
	if (attr && setup_max_cpus > (uintptr_t)attr->data) {
	dev_info(dev, "Watchdog blacklisted on %s %s\n", attr->soc_id,
	attr->revision);
	return true;
	}

	return false;
	}
	#else /* !CONFIG_ARCH_RCAR_GEN2 \|\| !CONFIG_SMP */
	static inline bool rwdt_blacklisted(struct device *dev) { return false; }
	#endif /* !CONFIG_ARCH_RCAR_GEN2 \|\| !CONFIG_SMP */

	static int rwdt_probe(struct platform_device *pdev)
	{
	struct rwdt_priv *priv;
	struct clk *clk;
	unsigned long clks_per_sec;
	int ret, i;

	if (rwdt_blacklisted(&pdev->dev))
	return -ENODEV;

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->base))
	return PTR_ERR(priv->base);

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk))
	return PTR_ERR(clk);

	pm_runtime_enable(&pdev->dev);
	pm_runtime_get_sync(&pdev->dev);
	priv->clk_rate = clk_get_rate(clk);
	priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) &
	RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0;
	pm_runtime_put(&pdev->dev);

	if (!priv->clk_rate) {
	ret = -ENOENT;
	goto out_pm_disable;
	}

	for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
	clks_per_sec = priv->clk_rate / clk_divs[i];
	if (clks_per_sec && clks_per_sec < 65536) {
	priv->cks = i;
	break;
	}
	}

	if (i < 0) {
	dev_err(&pdev->dev, "Can't find suitable clock divider\n");
	ret = -ERANGE;
	goto out_pm_disable;
	}

	priv->wdev.info = &rwdt_ident;
	priv->wdev.ops = &rwdt_ops;
	priv->wdev.parent = &pdev->dev;
	priv->wdev.min_timeout = 1;
	priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536);
	priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT);

	platform_set_drvdata(pdev, priv);
	watchdog_set_drvdata(&priv->wdev, priv);
	watchdog_set_nowayout(&priv->wdev, nowayout);
	watchdog_set_restart_priority(&priv->wdev, 0);
	watchdog_stop_on_unregister(&priv->wdev);

	/* This overrides the default timeout only if DT configuration was found */
	ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
	if (ret)
	dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n");

	ret = watchdog_register_device(&priv->wdev);
	if (ret < 0)
	goto out_pm_disable;

	return 0;

	out_pm_disable:
	pm_runtime_disable(&pdev->dev);
	return ret;
	}

	static int rwdt_remove(struct platform_device *pdev)
	{
	struct rwdt_priv *priv = platform_get_drvdata(pdev);

	watchdog_unregister_device(&priv->wdev);
	pm_runtime_disable(&pdev->dev);

	return 0;
	}

	static int __maybe_unused rwdt_suspend(struct device *dev)
	{
	struct rwdt_priv *priv = dev_get_drvdata(dev);

	if (watchdog_active(&priv->wdev))
	rwdt_stop(&priv->wdev);

	return 0;
	}

	static int __maybe_unused rwdt_resume(struct device *dev)
	{
	struct rwdt_priv *priv = dev_get_drvdata(dev);

	if (watchdog_active(&priv->wdev))
	rwdt_start(&priv->wdev);

	return 0;
	}

	static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume);

	static const struct of_device_id rwdt_ids[] = {
	{ .compatible = "renesas,rcar-gen2-wdt", },
	{ .compatible = "renesas,rcar-gen3-wdt", },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, rwdt_ids);

	static struct platform_driver rwdt_driver = {
	.driver = {
	.name = "renesas_wdt",
	.of_match_table = rwdt_ids,
	.pm = &rwdt_pm_ops,
	},
	.probe = rwdt_probe,
	.remove = rwdt_remove,
	};
	module_platform_driver(rwdt_driver);

	MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");