drivers/watchdog/orion_wdt.c - linux-mtk - Git at Google

 /*
  * drivers/watchdog/orion_wdt.c
  *
  * Watchdog driver for Orion/Kirkwood processors
  *
  * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
  *
  * This file is licensed under  the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/of.h>
 #include <mach/bridge-regs.h>

 /* RSTOUT mask register physical address for Orion5x, Kirkwood and Dove */
 #define ORION_RSTOUT_MASK_OFFSET	0x20108

 /* Internal registers can be configured at any 1 MiB aligned address */
 #define INTERNAL_REGS_MASK		~(SZ_1M - 1)

 /*
  * Watchdog timer block registers.
  */
 #define TIMER_CTRL		0x0000
 #define WDT_EN			0x0010
 #define WDT_VAL			0x0024

 #define WDT_MAX_CYCLE_COUNT	0xffffffff

 #define WDT_RESET_OUT_EN	BIT(1)
 #define WDT_INT_REQ		BIT(3)

 static bool nowayout = WATCHDOG_NOWAYOUT;
 static int heartbeat = -1;		/* module parameter (seconds) */
 static unsigned int wdt_max_duration;	/* (seconds) */
 static struct clk *clk;
 static unsigned int wdt_tclk;
 static void __iomem *wdt_reg;
 static void __iomem *wdt_rstout;

 static int orion_wdt_ping(struct watchdog_device *wdt_dev)
 {
 	/* Reload watchdog duration */
 	writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
 	return 0;
 }

 static int orion_wdt_start(struct watchdog_device *wdt_dev)
 {
 	/* Set watchdog duration */
 	writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);

 	/* Clear watchdog timer interrupt */
 	writel(~WDT_INT_REQ, BRIDGE_CAUSE);

 	/* Enable watchdog timer */
 	atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, WDT_EN);

 	/* Enable reset on watchdog */
 	atomic_io_modify(wdt_rstout, WDT_RESET_OUT_EN, WDT_RESET_OUT_EN);
 	return 0;
 }

 static int orion_wdt_stop(struct watchdog_device *wdt_dev)
 {
 	/* Disable reset on watchdog */
 	atomic_io_modify(wdt_rstout, WDT_RESET_OUT_EN, 0);

 	/* Disable watchdog timer */
 	atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, 0);
 	return 0;
 }

 static int orion_wdt_enabled(void)
 {
 	bool enabled, running;

 	enabled = readl(wdt_rstout) & WDT_RESET_OUT_EN;
 	running = readl(wdt_reg + TIMER_CTRL) & WDT_EN;

 	return enabled && running;
 }

 static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
 {
 	return readl(wdt_reg + WDT_VAL) / wdt_tclk;
 }

 static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
 				 unsigned int timeout)
 {
 	wdt_dev->timeout = timeout;
 	return 0;
 }

 static const struct watchdog_info orion_wdt_info = {
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 	.identity = "Orion Watchdog",
 };

 static const struct watchdog_ops orion_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = orion_wdt_start,
 	.stop = orion_wdt_stop,
 	.ping = orion_wdt_ping,
 	.set_timeout = orion_wdt_set_timeout,
 	.get_timeleft = orion_wdt_get_timeleft,
 };

 static struct watchdog_device orion_wdt = {
 	.info = &orion_wdt_info,
 	.ops = &orion_wdt_ops,
 	.min_timeout = 1,
 };

 static irqreturn_t orion_wdt_irq(int irq, void *devid)
 {
 	panic("Watchdog Timeout");
 	return IRQ_HANDLED;
 }

 /*
  * The original devicetree binding for this driver specified only
  * one memory resource, so in order to keep DT backwards compatibility
  * we try to fallback to a hardcoded register address, if the resource
  * is missing from the devicetree.
  */
 static void __iomem *orion_wdt_ioremap_rstout(struct platform_device *pdev,
 					      phys_addr_t internal_regs)
 {
 	struct resource *res;
 	phys_addr_t rstout;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	if (res)
 		return devm_ioremap(&pdev->dev, res->start,
 				    resource_size(res));

 	/* This workaround works only for "orion-wdt", DT-enabled */
 	if (!of_device_is_compatible(pdev->dev.of_node, "marvell,orion-wdt"))
 		return NULL;

 	rstout = internal_regs + ORION_RSTOUT_MASK_OFFSET;

 	WARN(1, FW_BUG "falling back to harcoded RSTOUT reg 0x%x\n", rstout);
 	return devm_ioremap(&pdev->dev, rstout, 0x4);
 }

 static int orion_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	int ret, irq;

 	clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(clk)) {
 		dev_err(&pdev->dev, "Orion Watchdog missing clock\n");
 		return PTR_ERR(clk);
 	}
 	ret = clk_prepare_enable(clk);
 	if (ret)
 		return ret;
 	wdt_tclk = clk_get_rate(clk);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		ret = -ENODEV;
 		goto disable_clk;
 	}

 	wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 	if (!wdt_reg) {
 		ret = -ENOMEM;
 		goto disable_clk;
 	}

 	wdt_rstout = orion_wdt_ioremap_rstout(pdev, res->start &
 						    INTERNAL_REGS_MASK);
 	if (!wdt_rstout) {
 		ret = -ENODEV;
 		goto disable_clk;
 	}

 	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;

 	orion_wdt.timeout = wdt_max_duration;
 	orion_wdt.max_timeout = wdt_max_duration;
 	watchdog_init_timeout(&orion_wdt, heartbeat, &pdev->dev);

 	/*
 	 * Let's make sure the watchdog is fully stopped, unless it's
 	 * explicitly enabled. This may be the case if the module was
 	 * removed and re-insterted, or if the bootloader explicitly
 	 * set a running watchdog before booting the kernel.
 	 */
 	if (!orion_wdt_enabled())
 		orion_wdt_stop(&orion_wdt);

 	/* Request the IRQ only after the watchdog is disabled */
 	irq = platform_get_irq(pdev, 0);
 	if (irq > 0) {
 		/*
 		 * Not all supported platforms specify an interrupt for the
 		 * watchdog, so let's make it optional.
 		 */
 		ret = devm_request_irq(&pdev->dev, irq, orion_wdt_irq, 0,
 				       pdev->name, &orion_wdt);
 		if (ret < 0) {
 			dev_err(&pdev->dev, "failed to request IRQ\n");
 			goto disable_clk;
 		}
 	}

 	watchdog_set_nowayout(&orion_wdt, nowayout);
 	ret = watchdog_register_device(&orion_wdt);
 	if (ret)
 		goto disable_clk;

 	pr_info("Initial timeout %d sec%s\n",
 		orion_wdt.timeout, nowayout ? ", nowayout" : "");
 	return 0;

 disable_clk:
 	clk_disable_unprepare(clk);
 	return ret;
 }

 static int orion_wdt_remove(struct platform_device *pdev)
 {
 	watchdog_unregister_device(&orion_wdt);
 	clk_disable_unprepare(clk);
 	return 0;
 }

 static void orion_wdt_shutdown(struct platform_device *pdev)
 {
 	orion_wdt_stop(&orion_wdt);
 }

 static const struct of_device_id orion_wdt_of_match_table[] = {
 	{ .compatible = "marvell,orion-wdt", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);

 static struct platform_driver orion_wdt_driver = {
 	.probe		= orion_wdt_probe,
 	.remove		= orion_wdt_remove,
 	.shutdown	= orion_wdt_shutdown,
 	.driver		= {
 		.owner	= THIS_MODULE,
 		.name	= "orion_wdt",
 		.of_match_table = orion_wdt_of_match_table,
 	},
 };

 module_platform_driver(orion_wdt_driver);

 MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
 MODULE_DESCRIPTION("Orion Processor Watchdog");

 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");

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

 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:orion_wdt");
	/*
	* drivers/watchdog/orion_wdt.c
	*
	* Watchdog driver for Orion/Kirkwood processors
	*
	* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/platform_device.h>
	#include <linux/watchdog.h>
	#include <linux/init.h>
	#include <linux/interrupt.h>
	#include <linux/io.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/of.h>
	#include <mach/bridge-regs.h>

	/* RSTOUT mask register physical address for Orion5x, Kirkwood and Dove */
	#define ORION_RSTOUT_MASK_OFFSET 0x20108

	/* Internal registers can be configured at any 1 MiB aligned address */
	#define INTERNAL_REGS_MASK ~(SZ_1M - 1)

	/*
	* Watchdog timer block registers.
	*/
	#define TIMER_CTRL 0x0000
	#define WDT_EN 0x0010
	#define WDT_VAL 0x0024

	#define WDT_MAX_CYCLE_COUNT 0xffffffff

	#define WDT_RESET_OUT_EN BIT(1)
	#define WDT_INT_REQ BIT(3)

	static bool nowayout = WATCHDOG_NOWAYOUT;
	static int heartbeat = -1; /* module parameter (seconds) */
	static unsigned int wdt_max_duration; /* (seconds) */
	static struct clk *clk;
	static unsigned int wdt_tclk;
	static void __iomem *wdt_reg;
	static void __iomem *wdt_rstout;

	static int orion_wdt_ping(struct watchdog_device *wdt_dev)
	{
	/* Reload watchdog duration */
	writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);
	return 0;
	}

	static int orion_wdt_start(struct watchdog_device *wdt_dev)
	{
	/* Set watchdog duration */
	writel(wdt_tclk * wdt_dev->timeout, wdt_reg + WDT_VAL);

	/* Clear watchdog timer interrupt */
	writel(~WDT_INT_REQ, BRIDGE_CAUSE);

	/* Enable watchdog timer */
	atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, WDT_EN);

	/* Enable reset on watchdog */
	atomic_io_modify(wdt_rstout, WDT_RESET_OUT_EN, WDT_RESET_OUT_EN);
	return 0;
	}

	static int orion_wdt_stop(struct watchdog_device *wdt_dev)
	{
	/* Disable reset on watchdog */
	atomic_io_modify(wdt_rstout, WDT_RESET_OUT_EN, 0);

	/* Disable watchdog timer */
	atomic_io_modify(wdt_reg + TIMER_CTRL, WDT_EN, 0);
	return 0;
	}

	static int orion_wdt_enabled(void)
	{
	bool enabled, running;

	enabled = readl(wdt_rstout) & WDT_RESET_OUT_EN;
	running = readl(wdt_reg + TIMER_CTRL) & WDT_EN;

	return enabled && running;
	}

	static unsigned int orion_wdt_get_timeleft(struct watchdog_device *wdt_dev)
	{
	return readl(wdt_reg + WDT_VAL) / wdt_tclk;
	}

	static int orion_wdt_set_timeout(struct watchdog_device *wdt_dev,
	unsigned int timeout)
	{
	wdt_dev->timeout = timeout;
	return 0;
	}

	static const struct watchdog_info orion_wdt_info = {
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	.identity = "Orion Watchdog",
	};

	static const struct watchdog_ops orion_wdt_ops = {
	.owner = THIS_MODULE,
	.start = orion_wdt_start,
	.stop = orion_wdt_stop,
	.ping = orion_wdt_ping,
	.set_timeout = orion_wdt_set_timeout,
	.get_timeleft = orion_wdt_get_timeleft,
	};

	static struct watchdog_device orion_wdt = {
	.info = &orion_wdt_info,
	.ops = &orion_wdt_ops,
	.min_timeout = 1,
	};

	static irqreturn_t orion_wdt_irq(int irq, void *devid)
	{
	panic("Watchdog Timeout");
	return IRQ_HANDLED;
	}

	/*
	* The original devicetree binding for this driver specified only
	* one memory resource, so in order to keep DT backwards compatibility
	* we try to fallback to a hardcoded register address, if the resource
	* is missing from the devicetree.
	*/
	static void __iomem orion_wdt_ioremap_rstout(struct platform_device pdev,
	phys_addr_t internal_regs)
	{
	struct resource *res;
	phys_addr_t rstout;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (res)
	return devm_ioremap(&pdev->dev, res->start,
	resource_size(res));

	/* This workaround works only for "orion-wdt", DT-enabled */
	if (!of_device_is_compatible(pdev->dev.of_node, "marvell,orion-wdt"))
	return NULL;

	rstout = internal_regs + ORION_RSTOUT_MASK_OFFSET;

	WARN(1, FW_BUG "falling back to harcoded RSTOUT reg 0x%x\n", rstout);
	return devm_ioremap(&pdev->dev, rstout, 0x4);
	}

	static int orion_wdt_probe(struct platform_device *pdev)
	{
	struct resource *res;
	int ret, irq;

	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
	dev_err(&pdev->dev, "Orion Watchdog missing clock\n");
	return PTR_ERR(clk);
	}
	ret = clk_prepare_enable(clk);
	if (ret)
	return ret;
	wdt_tclk = clk_get_rate(clk);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
	ret = -ENODEV;
	goto disable_clk;
	}

	wdt_reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	if (!wdt_reg) {
	ret = -ENOMEM;
	goto disable_clk;
	}

	wdt_rstout = orion_wdt_ioremap_rstout(pdev, res->start &
	INTERNAL_REGS_MASK);
	if (!wdt_rstout) {
	ret = -ENODEV;
	goto disable_clk;
	}

	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;

	orion_wdt.timeout = wdt_max_duration;
	orion_wdt.max_timeout = wdt_max_duration;
	watchdog_init_timeout(&orion_wdt, heartbeat, &pdev->dev);

	/*
	* Let's make sure the watchdog is fully stopped, unless it's
	* explicitly enabled. This may be the case if the module was
	* removed and re-insterted, or if the bootloader explicitly
	* set a running watchdog before booting the kernel.
	*/
	if (!orion_wdt_enabled())
	orion_wdt_stop(&orion_wdt);

	/* Request the IRQ only after the watchdog is disabled */
	irq = platform_get_irq(pdev, 0);
	if (irq > 0) {
	/*
	* Not all supported platforms specify an interrupt for the
	* watchdog, so let's make it optional.
	*/
	ret = devm_request_irq(&pdev->dev, irq, orion_wdt_irq, 0,
	pdev->name, &orion_wdt);
	if (ret < 0) {
	dev_err(&pdev->dev, "failed to request IRQ\n");
	goto disable_clk;
	}
	}

	watchdog_set_nowayout(&orion_wdt, nowayout);
	ret = watchdog_register_device(&orion_wdt);
	if (ret)
	goto disable_clk;

	pr_info("Initial timeout %d sec%s\n",
	orion_wdt.timeout, nowayout ? ", nowayout" : "");
	return 0;

	disable_clk:
	clk_disable_unprepare(clk);
	return ret;
	}

	static int orion_wdt_remove(struct platform_device *pdev)
	{
	watchdog_unregister_device(&orion_wdt);
	clk_disable_unprepare(clk);
	return 0;
	}

	static void orion_wdt_shutdown(struct platform_device *pdev)
	{
	orion_wdt_stop(&orion_wdt);
	}

	static const struct of_device_id orion_wdt_of_match_table[] = {
	{ .compatible = "marvell,orion-wdt", },
	{},
	};
	MODULE_DEVICE_TABLE(of, orion_wdt_of_match_table);

	static struct platform_driver orion_wdt_driver = {
	.probe = orion_wdt_probe,
	.remove = orion_wdt_remove,
	.shutdown = orion_wdt_shutdown,
	.driver = {
	.owner = THIS_MODULE,
	.name = "orion_wdt",
	.of_match_table = orion_wdt_of_match_table,
	},
	};

	module_platform_driver(orion_wdt_driver);

	MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
	MODULE_DESCRIPTION("Orion Processor Watchdog");

	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");

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

	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:orion_wdt");