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

 /* Copyright (c) 2014, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  */
 #include <linux/clk.h>
 #include <linux/delay.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,
 };

 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 {
 	struct watchdog_device	wdd;
 	struct clk		*clk;
 	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 int qcom_wdt_start(struct watchdog_device *wdd)
 {
 	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

 	writel(0, wdt_addr(wdt, WDT_EN));
 	writel(1, wdt_addr(wdt, WDT_RST));
 	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
 	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
 	writel(1, 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_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(1, wdt_addr(wdt, WDT_EN));

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

 	msleep(150);
 	return 0;
 }

 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,
 	.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 int qcom_wdt_probe(struct platform_device *pdev)
 {
 	struct qcom_wdt *wdt;
 	struct resource *res;
 	struct device_node *np = pdev->dev.of_node;
 	const u32 *regs;
 	u32 percpu_offset;
 	int ret;

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

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

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

 	/* 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(&pdev->dev, res);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);

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

 	ret = clk_prepare_enable(wdt->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to setup clock\n");
 		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(wdt->clk);
 	if (wdt->rate == 0 ||
 	    wdt->rate > 0x10000000U) {
 		dev_err(&pdev->dev, "invalid clock rate\n");
 		ret = -EINVAL;
 		goto err_clk_unprepare;
 	}

 	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 = &pdev->dev;
 	wdt->layout = regs;

 	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, &pdev->dev);

 	ret = watchdog_register_device(&wdt->wdd);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register watchdog\n");
 		goto err_clk_unprepare;
 	}

 	platform_set_drvdata(pdev, wdt);
 	return 0;

 err_clk_unprepare:
 	clk_disable_unprepare(wdt->clk);
 	return ret;
 }

 static int qcom_wdt_remove(struct platform_device *pdev)
 {
 	struct qcom_wdt *wdt = platform_get_drvdata(pdev);

 	watchdog_unregister_device(&wdt->wdd);
 	clk_disable_unprepare(wdt->clk);
 	return 0;
 }

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

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

 MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
 MODULE_LICENSE("GPL v2");
	/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	*/
	#include <linux/clk.h>
	#include <linux/delay.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,
	};

	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 {
	struct watchdog_device wdd;
	struct clk *clk;
	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 int qcom_wdt_start(struct watchdog_device *wdd)
	{
	struct qcom_wdt *wdt = to_qcom_wdt(wdd);

	writel(0, wdt_addr(wdt, WDT_EN));
	writel(1, wdt_addr(wdt, WDT_RST));
	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
	writel(1, 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_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(1, wdt_addr(wdt, WDT_EN));

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

	msleep(150);
	return 0;
	}

	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,
	.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 int qcom_wdt_probe(struct platform_device *pdev)
	{
	struct qcom_wdt *wdt;
	struct resource *res;
	struct device_node *np = pdev->dev.of_node;
	const u32 *regs;
	u32 percpu_offset;
	int ret;

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

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

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	/* 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(&pdev->dev, res);
	if (IS_ERR(wdt->base))
	return PTR_ERR(wdt->base);

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

	ret = clk_prepare_enable(wdt->clk);
	if (ret) {
	dev_err(&pdev->dev, "failed to setup clock\n");
	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(wdt->clk);
	if (wdt->rate == 0 \|\|
	wdt->rate > 0x10000000U) {
	dev_err(&pdev->dev, "invalid clock rate\n");
	ret = -EINVAL;
	goto err_clk_unprepare;
	}

	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 = &pdev->dev;
	wdt->layout = regs;

	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, &pdev->dev);

	ret = watchdog_register_device(&wdt->wdd);
	if (ret) {
	dev_err(&pdev->dev, "failed to register watchdog\n");
	goto err_clk_unprepare;
	}

	platform_set_drvdata(pdev, wdt);
	return 0;

	err_clk_unprepare:
	clk_disable_unprepare(wdt->clk);
	return ret;
	}

	static int qcom_wdt_remove(struct platform_device *pdev)
	{
	struct qcom_wdt *wdt = platform_get_drvdata(pdev);

	watchdog_unregister_device(&wdt->wdd);
	clk_disable_unprepare(wdt->clk);
	return 0;
	}

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

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

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