drivers/watchdog/qcom-wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2014, The Linux Foundation. All rights reserved.
  */
 #include <linux/bits.h>
 #include <linux/clk.h>
 #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/platform_device.h>
 #include <linux/watchdog.h>
 #include <linux/of_device.h>

 enum wdt_reg {
 	WDT_RST,
 	WDT_EN,
 	WDT_STS,
 	WDT_BARK_TIME,
 	WDT_BITE_TIME,
 };

 #define QCOM_WDT_ENABLE		BIT(0)
 #define QCOM_WDT_ENABLE_IRQ	BIT(1)

 static const u32 reg_offset_data_apcs_tmr[] = {
 	[WDT_RST] = 0x38,
 	[WDT_EN] = 0x40,
 	[WDT_STS] = 0x44,
 	[WDT_BARK_TIME] = 0x4C,
 	[WDT_BITE_TIME] = 0x5C,
 };

 static const u32 reg_offset_data_kpss[] = {
 	[WDT_RST] = 0x4,
 	[WDT_EN] = 0x8,
 	[WDT_STS] = 0xC,
 	[WDT_BARK_TIME] = 0x10,
 	[WDT_BITE_TIME] = 0x14,
 };

 struct qcom_wdt_match_data {
 	const u32 *offset;
 	bool pretimeout;
 };

 struct qcom_wdt {
 	struct watchdog_device	wdd;
 	unsigned long		rate;
 	void __iomem		*base;
 	const u32		*layout;
 };

 static void __iomem *wdt_addr(struct qcom_wdt *wdt, enum wdt_reg reg)
 {
 	return wdt->base + wdt->layout[reg];
 }

 static inline
 struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
 {
 	return container_of(wdd, struct qcom_wdt, wdd);
 }

 static inline int qcom_get_enable(struct watchdog_device *wdd)
 {
 	int enable = QCOM_WDT_ENABLE;

 	if (wdd->pretimeout)
 		enable |= QCOM_WDT_ENABLE_IRQ;

 	return enable;
 }

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

 	watchdog_notify_pretimeout(wdd);

 	return IRQ_HANDLED;
 }

 static int qcom_wdt_start(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
 	unsigned int bark = wdd->timeout - wdd->pretimeout;

 	writel(0, wdt_addr(wdt, WDT_EN));
 	writel(1, wdt_addr(wdt, WDT_RST));
 	writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
 	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
 	writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
 	return 0;
 }

 static int qcom_wdt_stop(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

 	writel(0, wdt_addr(wdt, WDT_EN));
 	return 0;
 }

 static int qcom_wdt_ping(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

 	writel(1, wdt_addr(wdt, WDT_RST));
 	return 0;
 }

 static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
 				unsigned int timeout)
 {
 	wdd->timeout = timeout;
 	return qcom_wdt_start(wdd);
 }

 static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
 				   unsigned int timeout)
 {
 	wdd->pretimeout = timeout;
 	return qcom_wdt_start(wdd);
 }

 static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
 			    void *data)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
 	u32 timeout;

 	/*
 	 * Trigger watchdog bite:
 	 *    Setup BITE_TIME to be 128ms, and enable WDT.
 	 */
 	timeout = 128 * wdt->rate / 1000;

 	writel(0, wdt_addr(wdt, WDT_EN));
 	writel(1, wdt_addr(wdt, WDT_RST));
 	writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
 	writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
 	writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));

 	/*
 	 * Actually make sure the above sequence hits hardware before sleeping.
 	 */
 	wmb();

 	mdelay(150);
 	return 0;
 }

 static int qcom_wdt_is_running(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

 	return (readl(wdt_addr(wdt, WDT_EN)) & QCOM_WDT_ENABLE);
 }

 static const struct watchdog_ops qcom_wdt_ops = {
 	.start		= qcom_wdt_start,
 	.stop		= qcom_wdt_stop,
 	.ping		= qcom_wdt_ping,
 	.set_timeout	= qcom_wdt_set_timeout,
 	.set_pretimeout	= qcom_wdt_set_pretimeout,
 	.restart        = qcom_wdt_restart,
 	.owner		= THIS_MODULE,
 };

 static const struct watchdog_info qcom_wdt_info = {
 	.options	= WDIOF_KEEPALIVEPING
 			| WDIOF_MAGICCLOSE
 			| WDIOF_SETTIMEOUT
 			| WDIOF_CARDRESET,
 	.identity	= KBUILD_MODNAME,
 };

 static const struct watchdog_info qcom_wdt_pt_info = {
 	.options	= WDIOF_KEEPALIVEPING
 			| WDIOF_MAGICCLOSE
 			| WDIOF_SETTIMEOUT
 			| WDIOF_PRETIMEOUT
 			| WDIOF_CARDRESET,
 	.identity	= KBUILD_MODNAME,
 };

 static void qcom_clk_disable_unprepare(void *data)
 {
 	clk_disable_unprepare(data);
 }

 static const struct qcom_wdt_match_data match_data_apcs_tmr = {
 	.offset = reg_offset_data_apcs_tmr,
 	.pretimeout = false,
 };

 static const struct qcom_wdt_match_data match_data_kpss = {
 	.offset = reg_offset_data_kpss,
 	.pretimeout = true,
 };

 static int qcom_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct qcom_wdt *wdt;
 	struct resource *res;
 	struct device_node *np = dev->of_node;
 	const struct qcom_wdt_match_data *data;
 	u32 percpu_offset;
 	int irq, ret;
 	struct clk *clk;

 	data = of_device_get_match_data(dev);
 	if (!data) {
 		dev_err(dev, "Unsupported QCOM WDT module\n");
 		return -ENODEV;
 	}

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

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENOMEM;

 	/* We use CPU0's DGT for the watchdog */
 	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
 		percpu_offset = 0;

 	res->start += percpu_offset;
 	res->end += percpu_offset;

 	wdt->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);

 	clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(dev, "failed to get input clock\n");
 		return PTR_ERR(clk);
 	}

 	ret = clk_prepare_enable(clk);
 	if (ret) {
 		dev_err(dev, "failed to setup clock\n");
 		return ret;
 	}
 	ret = devm_add_action_or_reset(dev, qcom_clk_disable_unprepare, clk);
 	if (ret)
 		return ret;

 	/*
 	 * We use the clock rate to calculate the max timeout, so ensure it's
 	 * not zero to avoid a divide-by-zero exception.
 	 *
 	 * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
 	 * that it would bite before a second elapses it's usefulness is
 	 * limited.  Bail if this is the case.
 	 */
 	wdt->rate = clk_get_rate(clk);
 	if (wdt->rate == 0 ||
 	    wdt->rate > 0x10000000U) {
 		dev_err(dev, "invalid clock rate\n");
 		return -EINVAL;
 	}

 	/* check if there is pretimeout support */
 	irq = platform_get_irq_optional(pdev, 0);
 	if (data->pretimeout && irq > 0) {
 		ret = devm_request_irq(dev, irq, qcom_wdt_isr, 0,
 				       "wdt_bark", &wdt->wdd);
 		if (ret)
 			return ret;

 		wdt->wdd.info = &qcom_wdt_pt_info;
 		wdt->wdd.pretimeout = 1;
 	} else {
 		if (irq == -EPROBE_DEFER)
 			return -EPROBE_DEFER;

 		wdt->wdd.info = &qcom_wdt_info;
 	}

 	wdt->wdd.ops = &qcom_wdt_ops;
 	wdt->wdd.min_timeout = 1;
 	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
 	wdt->wdd.parent = dev;
 	wdt->layout = data->offset;

 	if (readl(wdt_addr(wdt, WDT_STS)) & 1)
 		wdt->wdd.bootstatus = WDIOF_CARDRESET;

 	/*
 	 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
 	 * default, unless the max timeout is less than 30 seconds, then use
 	 * the max instead.
 	 */
 	wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
 	watchdog_init_timeout(&wdt->wdd, 0, dev);

 	/*
 	 * If WDT is already running, call WDT start which
 	 * will stop the WDT, set timeouts as bootloader
 	 * might use different ones and set running bit
 	 * to inform the WDT subsystem to ping the WDT
 	 */
 	if (qcom_wdt_is_running(&wdt->wdd)) {
 		qcom_wdt_start(&wdt->wdd);
 		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
 	}

 	ret = devm_watchdog_register_device(dev, &wdt->wdd);
 	if (ret)
 		return ret;

 	platform_set_drvdata(pdev, wdt);
 	return 0;
 }

 static int __maybe_unused qcom_wdt_suspend(struct device *dev)
 {
 	struct qcom_wdt *wdt = dev_get_drvdata(dev);

 	if (watchdog_active(&wdt->wdd))
 		qcom_wdt_stop(&wdt->wdd);

 	return 0;
 }

 static int __maybe_unused qcom_wdt_resume(struct device *dev)
 {
 	struct qcom_wdt *wdt = dev_get_drvdata(dev);

 	if (watchdog_active(&wdt->wdd))
 		qcom_wdt_start(&wdt->wdd);

 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(qcom_wdt_pm_ops, qcom_wdt_suspend, qcom_wdt_resume);

 static const struct of_device_id qcom_wdt_of_table[] = {
 	{ .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr },
 	{ .compatible = "qcom,scss-timer", .data = &match_data_apcs_tmr },
 	{ .compatible = "qcom,kpss-wdt", .data = &match_data_kpss },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);

 static struct platform_driver qcom_watchdog_driver = {
 	.probe	= qcom_wdt_probe,
 	.driver	= {
 		.name		= KBUILD_MODNAME,
 		.of_match_table	= qcom_wdt_of_table,
 		.pm		= &qcom_wdt_pm_ops,
 	},
 };
 module_platform_driver(qcom_watchdog_driver);

 MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
	*/
	#include <linux/bits.h>
	#include <linux/clk.h>
	#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/platform_device.h>
	#include <linux/watchdog.h>
	#include <linux/of_device.h>

	enum wdt_reg {
	WDT_RST,
	WDT_EN,
	WDT_STS,
	WDT_BARK_TIME,
	WDT_BITE_TIME,
	};

	#define QCOM_WDT_ENABLE BIT(0)
	#define QCOM_WDT_ENABLE_IRQ BIT(1)

	static const u32 reg_offset_data_apcs_tmr[] = {
	[WDT_RST] = 0x38,
	[WDT_EN] = 0x40,
	[WDT_STS] = 0x44,
	[WDT_BARK_TIME] = 0x4C,
	[WDT_BITE_TIME] = 0x5C,
	};

	static const u32 reg_offset_data_kpss[] = {
	[WDT_RST] = 0x4,
	[WDT_EN] = 0x8,
	[WDT_STS] = 0xC,
	[WDT_BARK_TIME] = 0x10,
	[WDT_BITE_TIME] = 0x14,
	};

	struct qcom_wdt_match_data {
	const u32 *offset;
	bool pretimeout;
	};

	struct qcom_wdt {
	struct watchdog_device wdd;
	unsigned long rate;
	void __iomem *base;
	const u32 *layout;
	};

	static void __iomem wdt_addr(struct qcom_wdt wdt, enum wdt_reg reg)
	{
	return wdt->base + wdt->layout[reg];
	}

	static inline
	struct qcom_wdt to_qcom_wdt(struct watchdog_device wdd)
	{
	return container_of(wdd, struct qcom_wdt, wdd);
	}

	static inline int qcom_get_enable(struct watchdog_device *wdd)
	{
	int enable = QCOM_WDT_ENABLE;

	if (wdd->pretimeout)
	enable \|= QCOM_WDT_ENABLE_IRQ;

	return enable;
	}

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

	watchdog_notify_pretimeout(wdd);

	return IRQ_HANDLED;
	}

	static int qcom_wdt_start(struct watchdog_device *wdd)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
	unsigned int bark = wdd->timeout - wdd->pretimeout;

	writel(0, wdt_addr(wdt, WDT_EN));
	writel(1, wdt_addr(wdt, WDT_RST));
	writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
	writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
	return 0;
	}

	static int qcom_wdt_stop(struct watchdog_device *wdd)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

	writel(0, wdt_addr(wdt, WDT_EN));
	return 0;
	}

	static int qcom_wdt_ping(struct watchdog_device *wdd)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

	writel(1, wdt_addr(wdt, WDT_RST));
	return 0;
	}

	static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
	unsigned int timeout)
	{
	wdd->timeout = timeout;
	return qcom_wdt_start(wdd);
	}

	static int qcom_wdt_set_pretimeout(struct watchdog_device *wdd,
	unsigned int timeout)
	{
	wdd->pretimeout = timeout;
	return qcom_wdt_start(wdd);
	}

	static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action,
	void *data)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);
	u32 timeout;

	/*
	* Trigger watchdog bite:
	* Setup BITE_TIME to be 128ms, and enable WDT.
	*/
	timeout = 128 * wdt->rate / 1000;

	writel(0, wdt_addr(wdt, WDT_EN));
	writel(1, wdt_addr(wdt, WDT_RST));
	writel(timeout, wdt_addr(wdt, WDT_BARK_TIME));
	writel(timeout, wdt_addr(wdt, WDT_BITE_TIME));
	writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));

	/*
	* Actually make sure the above sequence hits hardware before sleeping.
	*/
	wmb();

	mdelay(150);
	return 0;
	}

	static int qcom_wdt_is_running(struct watchdog_device *wdd)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

	return (readl(wdt_addr(wdt, WDT_EN)) & QCOM_WDT_ENABLE);
	}

	static const struct watchdog_ops qcom_wdt_ops = {
	.start = qcom_wdt_start,
	.stop = qcom_wdt_stop,
	.ping = qcom_wdt_ping,
	.set_timeout = qcom_wdt_set_timeout,
	.set_pretimeout = qcom_wdt_set_pretimeout,
	.restart = qcom_wdt_restart,
	.owner = THIS_MODULE,
	};

	static const struct watchdog_info qcom_wdt_info = {
	.options = WDIOF_KEEPALIVEPING
	\| WDIOF_MAGICCLOSE
	\| WDIOF_SETTIMEOUT
	\| WDIOF_CARDRESET,
	.identity = KBUILD_MODNAME,
	};

	static const struct watchdog_info qcom_wdt_pt_info = {
	.options = WDIOF_KEEPALIVEPING
	\| WDIOF_MAGICCLOSE
	\| WDIOF_SETTIMEOUT
	\| WDIOF_PRETIMEOUT
	\| WDIOF_CARDRESET,
	.identity = KBUILD_MODNAME,
	};

	static void qcom_clk_disable_unprepare(void *data)
	{
	clk_disable_unprepare(data);
	}

	static const struct qcom_wdt_match_data match_data_apcs_tmr = {
	.offset = reg_offset_data_apcs_tmr,
	.pretimeout = false,
	};

	static const struct qcom_wdt_match_data match_data_kpss = {
	.offset = reg_offset_data_kpss,
	.pretimeout = true,
	};

	static int qcom_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct qcom_wdt *wdt;
	struct resource *res;
	struct device_node *np = dev->of_node;
	const struct qcom_wdt_match_data *data;
	u32 percpu_offset;
	int irq, ret;
	struct clk *clk;

	data = of_device_get_match_data(dev);
	if (!data) {
	dev_err(dev, "Unsupported QCOM WDT module\n");
	return -ENODEV;
	}

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

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENOMEM;

	/* We use CPU0's DGT for the watchdog */
	if (of_property_read_u32(np, "cpu-offset", &percpu_offset))
	percpu_offset = 0;

	res->start += percpu_offset;
	res->end += percpu_offset;

	wdt->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(wdt->base))
	return PTR_ERR(wdt->base);

	clk = devm_clk_get(dev, NULL);
	if (IS_ERR(clk)) {
	dev_err(dev, "failed to get input clock\n");
	return PTR_ERR(clk);
	}

	ret = clk_prepare_enable(clk);
	if (ret) {
	dev_err(dev, "failed to setup clock\n");
	return ret;
	}
	ret = devm_add_action_or_reset(dev, qcom_clk_disable_unprepare, clk);
	if (ret)
	return ret;

	/*
	* We use the clock rate to calculate the max timeout, so ensure it's
	* not zero to avoid a divide-by-zero exception.
	*
	* WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
	* that it would bite before a second elapses it's usefulness is
	* limited. Bail if this is the case.
	*/
	wdt->rate = clk_get_rate(clk);
	if (wdt->rate == 0 \|\|
	wdt->rate > 0x10000000U) {
	dev_err(dev, "invalid clock rate\n");
	return -EINVAL;
	}

	/* check if there is pretimeout support */
	irq = platform_get_irq_optional(pdev, 0);
	if (data->pretimeout && irq > 0) {
	ret = devm_request_irq(dev, irq, qcom_wdt_isr, 0,
	"wdt_bark", &wdt->wdd);
	if (ret)
	return ret;

	wdt->wdd.info = &qcom_wdt_pt_info;
	wdt->wdd.pretimeout = 1;
	} else {
	if (irq == -EPROBE_DEFER)
	return -EPROBE_DEFER;

	wdt->wdd.info = &qcom_wdt_info;
	}

	wdt->wdd.ops = &qcom_wdt_ops;
	wdt->wdd.min_timeout = 1;
	wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
	wdt->wdd.parent = dev;
	wdt->layout = data->offset;

	if (readl(wdt_addr(wdt, WDT_STS)) & 1)
	wdt->wdd.bootstatus = WDIOF_CARDRESET;

	/*
	* If 'timeout-sec' unspecified in devicetree, assume a 30 second
	* default, unless the max timeout is less than 30 seconds, then use
	* the max instead.
	*/
	wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
	watchdog_init_timeout(&wdt->wdd, 0, dev);

	/*
	* If WDT is already running, call WDT start which
	* will stop the WDT, set timeouts as bootloader
	* might use different ones and set running bit
	* to inform the WDT subsystem to ping the WDT
	*/
	if (qcom_wdt_is_running(&wdt->wdd)) {
	qcom_wdt_start(&wdt->wdd);
	set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
	}

	ret = devm_watchdog_register_device(dev, &wdt->wdd);
	if (ret)
	return ret;

	platform_set_drvdata(pdev, wdt);
	return 0;
	}

	static int __maybe_unused qcom_wdt_suspend(struct device *dev)
	{
	struct qcom_wdt *wdt = dev_get_drvdata(dev);

	if (watchdog_active(&wdt->wdd))
	qcom_wdt_stop(&wdt->wdd);

	return 0;
	}

	static int __maybe_unused qcom_wdt_resume(struct device *dev)
	{
	struct qcom_wdt *wdt = dev_get_drvdata(dev);

	if (watchdog_active(&wdt->wdd))
	qcom_wdt_start(&wdt->wdd);

	return 0;
	}

	static SIMPLE_DEV_PM_OPS(qcom_wdt_pm_ops, qcom_wdt_suspend, qcom_wdt_resume);

	static const struct of_device_id qcom_wdt_of_table[] = {
	{ .compatible = "qcom,kpss-timer", .data = &match_data_apcs_tmr },
	{ .compatible = "qcom,scss-timer", .data = &match_data_apcs_tmr },
	{ .compatible = "qcom,kpss-wdt", .data = &match_data_kpss },
	{ },
	};
	MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);

	static struct platform_driver qcom_watchdog_driver = {
	.probe = qcom_wdt_probe,
	.driver = {
	.name = KBUILD_MODNAME,
	.of_match_table = qcom_wdt_of_table,
	.pm = &qcom_wdt_pm_ops,
	},
	};
	module_platform_driver(qcom_watchdog_driver);

	MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
	MODULE_LICENSE("GPL v2");