watchdog: Driver for the watchdog timer on Freescale IMX2 (and later) processors. (bb2fd8a8) · Commits · 戴 / test

drivers/watchdog/Kconfig

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		@@ -312,6 +312,18 @@ config MAX63XX_WATCHDOG
		help
		Support for memory mapped max63{69,70,71,72,73,74} watchdog timer.

		config IMX2_WDT
		tristate "IMX2+ Watchdog"
		depends on ARCH_MX2 \|\| ARCH_MX25 \|\| ARCH_MX3 \|\| ARCH_MX5
		help
		This is the driver for the hardware watchdog
		on the Freescale IMX2 and later processors.
		If you have one of these processors and wish to have
		watchdog support enabled, say Y, otherwise say N.

		To compile this driver as a module, choose M here: the
		module will be called imx2_wdt.

		# AVR32 Architecture

		config AT32AP700X_WDT

drivers/watchdog/Makefile

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		@@ -47,6 +47,7 @@ obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
		obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
		obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
		obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
		obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o

		# AVR32 Architecture
		obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/imx2_wdt.c

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Original line number	Diff line number	Diff line
		/*
		* Watchdog driver for IMX2 and later processors
		*
		* Copyright (C) 2010 Wolfram Sang, Pengutronix e.K. <w.sang@pengutronix.de>
		*
		* some parts adapted by similar drivers from Darius Augulis and Vladimir
		* Zapolskiy, additional improvements by Wim Van Sebroeck.
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License version 2 as published by
		* the Free Software Foundation.
		*
		* NOTE: MX1 has a slightly different Watchdog than MX2 and later:
		*
		* MX1: MX2+:
		* ---- -----
		* Registers: 32-bit 16-bit
		* Stopable timer: Yes No
		* Need to enable clk: No Yes
		* Halt on suspend: Manual Can be automatic
		*/

		#include <linux/init.h>
		#include <linux/kernel.h>
		#include <linux/miscdevice.h>
		#include <linux/module.h>
		#include <linux/moduleparam.h>
		#include <linux/platform_device.h>
		#include <linux/watchdog.h>
		#include <linux/clk.h>
		#include <linux/fs.h>
		#include <linux/io.h>
		#include <linux/uaccess.h>
		#include <linux/timer.h>
		#include <linux/jiffies.h>
		#include <mach/hardware.h>

		#define DRIVER_NAME "imx2-wdt"

		#define IMX2_WDT_WCR 0x00 /* Control Register */
		#define IMX2_WDT_WCR_WT (0xFF << 8) /* -> Watchdog Timeout Field */
		#define IMX2_WDT_WCR_WRE (1 << 3) /* -> WDOG Reset Enable */
		#define IMX2_WDT_WCR_WDE (1 << 2) /* -> Watchdog Enable */

		#define IMX2_WDT_WSR 0x02 /* Service Register */
		#define IMX2_WDT_SEQ1 0x5555 /* -> service sequence 1 */
		#define IMX2_WDT_SEQ2 0xAAAA /* -> service sequence 2 */

		#define IMX2_WDT_MAX_TIME 128
		#define IMX2_WDT_DEFAULT_TIME 60 /* in seconds */

		#define WDOG_SEC_TO_COUNT(s) ((s * 2 - 1) << 8)

		#define IMX2_WDT_STATUS_OPEN 0
		#define IMX2_WDT_STATUS_STARTED 1
		#define IMX2_WDT_EXPECT_CLOSE 2

		static struct {
		struct clk *clk;
		void __iomem *base;
		unsigned timeout;
		unsigned long status;
		struct timer_list timer; /* Pings the watchdog when closed */
		} imx2_wdt;

		static struct miscdevice imx2_wdt_miscdev;

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


		static unsigned timeout = IMX2_WDT_DEFAULT_TIME;
		module_param(timeout, uint, 0);
		MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
		__MODULE_STRING(IMX2_WDT_DEFAULT_TIME) ")");

		static const struct watchdog_info imx2_wdt_info = {
		.identity = "imx2+ watchdog",
		.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE,
		};

		static inline void imx2_wdt_setup(void)
		{
		u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);

		/* Strip the old watchdog Time-Out value */
		val &= ~IMX2_WDT_WCR_WT;
		/* Generate reset if WDOG times out */
		val &= ~IMX2_WDT_WCR_WRE;
		/* Keep Watchdog Disabled */
		val &= ~IMX2_WDT_WCR_WDE;
		/* Set the watchdog's Time-Out value */
		val \|= WDOG_SEC_TO_COUNT(imx2_wdt.timeout);

		__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);

		/* enable the watchdog */
		val \|= IMX2_WDT_WCR_WDE;
		__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
		}

		static inline void imx2_wdt_ping(void)
		{
		__raw_writew(IMX2_WDT_SEQ1, imx2_wdt.base + IMX2_WDT_WSR);
		__raw_writew(IMX2_WDT_SEQ2, imx2_wdt.base + IMX2_WDT_WSR);
		}

		static void imx2_wdt_timer_ping(unsigned long arg)
		{
		/* ping it every imx2_wdt.timeout / 2 seconds to prevent reboot */
		imx2_wdt_ping();
		mod_timer(&imx2_wdt.timer, jiffies + imx2_wdt.timeout * HZ / 2);
		}

		static void imx2_wdt_start(void)
		{
		if (!test_and_set_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
		/* at our first start we enable clock and do initialisations */
		clk_enable(imx2_wdt.clk);

		imx2_wdt_setup();
		} else /* delete the timer that pings the watchdog after close */
		del_timer_sync(&imx2_wdt.timer);

		/* Watchdog is enabled - time to reload the timeout value */
		imx2_wdt_ping();
		}

		static void imx2_wdt_stop(void)
		{
		/* we don't need a clk_disable, it cannot be disabled once started.
		* We use a timer to ping the watchdog while /dev/watchdog is closed */
		imx2_wdt_timer_ping(0);
		}

		static void imx2_wdt_set_timeout(int new_timeout)
		{
		u16 val = __raw_readw(imx2_wdt.base + IMX2_WDT_WCR);

		/* set the new timeout value in the WSR */
		val &= ~IMX2_WDT_WCR_WT;
		val \|= WDOG_SEC_TO_COUNT(new_timeout);
		__raw_writew(val, imx2_wdt.base + IMX2_WDT_WCR);
		}

		static int imx2_wdt_open(struct inode inode, struct file file)
		{
		if (test_and_set_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status))
		return -EBUSY;

		imx2_wdt_start();
		return nonseekable_open(inode, file);
		}

		static int imx2_wdt_close(struct inode inode, struct file file)
		{
		if (test_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status) && !nowayout)
		imx2_wdt_stop();
		else {
		dev_crit(imx2_wdt_miscdev.parent,
		"Unexpected close: Expect reboot!\n");
		imx2_wdt_ping();
		}

		clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
		clear_bit(IMX2_WDT_STATUS_OPEN, &imx2_wdt.status);
		return 0;
		}

		static long imx2_wdt_ioctl(struct file *file, unsigned int cmd,
		unsigned long arg)
		{
		void __user argp = (void __user )arg;
		int __user *p = argp;
		int new_value;

		switch (cmd) {
		case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &imx2_wdt_info,
		sizeof(struct watchdog_info)) ? -EFAULT : 0;

		case WDIOC_GETSTATUS:
		case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);

		case WDIOC_KEEPALIVE:
		imx2_wdt_ping();
		return 0;

		case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
		return -EFAULT;
		if ((new_value < 1) \|\| (new_value > IMX2_WDT_MAX_TIME))
		return -EINVAL;
		imx2_wdt_set_timeout(new_value);
		imx2_wdt.timeout = new_value;
		imx2_wdt_ping();

		/* Fallthrough to return current value */
		case WDIOC_GETTIMEOUT:
		return put_user(imx2_wdt.timeout, p);

		default:
		return -ENOTTY;
		}
		}

		static ssize_t imx2_wdt_write(struct file file, const char __user data,
		size_t len, loff_t *ppos)
		{
		size_t i;
		char c;

		if (len == 0) /* Can we see this even ? */
		return 0;

		clear_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
		/* scan to see whether or not we got the magic character */
		for (i = 0; i != len; i++) {
		if (get_user(c, data + i))
		return -EFAULT;
		if (c == 'V')
		set_bit(IMX2_WDT_EXPECT_CLOSE, &imx2_wdt.status);
		}

		imx2_wdt_ping();
		return len;
		}

		static const struct file_operations imx2_wdt_fops = {
		.owner = THIS_MODULE,
		.llseek = no_llseek,
		.unlocked_ioctl = imx2_wdt_ioctl,
		.open = imx2_wdt_open,
		.release = imx2_wdt_close,
		.write = imx2_wdt_write,
		};

		static struct miscdevice imx2_wdt_miscdev = {
		.minor = WATCHDOG_MINOR,
		.name = "watchdog",
		.fops = &imx2_wdt_fops,
		};

		static int __init imx2_wdt_probe(struct platform_device *pdev)
		{
		int ret;
		int res_size;
		struct resource *res;

		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
		if (!res) {
		dev_err(&pdev->dev, "can't get device resources\n");
		return -ENODEV;
		}

		res_size = resource_size(res);
		if (!devm_request_mem_region(&pdev->dev, res->start, res_size,
		res->name)) {
		dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
		res_size, res->start);
		return -ENOMEM;
		}

		imx2_wdt.base = devm_ioremap_nocache(&pdev->dev, res->start, res_size);
		if (!imx2_wdt.base) {
		dev_err(&pdev->dev, "ioremap failed\n");
		return -ENOMEM;
		}

		imx2_wdt.clk = clk_get_sys("imx-wdt.0", NULL);
		if (IS_ERR(imx2_wdt.clk)) {
		dev_err(&pdev->dev, "can't get Watchdog clock\n");
		return PTR_ERR(imx2_wdt.clk);
		}

		imx2_wdt.timeout = clamp_t(unsigned, timeout, 1, IMX2_WDT_MAX_TIME);
		if (imx2_wdt.timeout != timeout)
		dev_warn(&pdev->dev, "Initial timeout out of range! "
		"Clamped from %u to %u\n", timeout, imx2_wdt.timeout);

		setup_timer(&imx2_wdt.timer, imx2_wdt_timer_ping, 0);

		imx2_wdt_miscdev.parent = &pdev->dev;
		ret = misc_register(&imx2_wdt_miscdev);
		if (ret)
		goto fail;

		dev_info(&pdev->dev,
		"IMX2+ Watchdog Timer enabled. timeout=%ds (nowayout=%d)\n",
		imx2_wdt.timeout, nowayout);
		return 0;

		fail:
		imx2_wdt_miscdev.parent = NULL;
		clk_put(imx2_wdt.clk);
		return ret;
		}

		static int __exit imx2_wdt_remove(struct platform_device *pdev)
		{
		misc_deregister(&imx2_wdt_miscdev);

		if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
		del_timer_sync(&imx2_wdt.timer);

		dev_crit(imx2_wdt_miscdev.parent,
		"Device removed: Expect reboot!\n");
		} else
		clk_put(imx2_wdt.clk);

		imx2_wdt_miscdev.parent = NULL;
		return 0;
		}

		static void imx2_wdt_shutdown(struct platform_device *pdev)
		{
		if (test_bit(IMX2_WDT_STATUS_STARTED, &imx2_wdt.status)) {
		/* we are running, we need to delete the timer but will give
		* max timeout before reboot will take place */
		del_timer_sync(&imx2_wdt.timer);
		imx2_wdt_set_timeout(IMX2_WDT_MAX_TIME);
		imx2_wdt_ping();

		dev_crit(imx2_wdt_miscdev.parent,
		"Device shutdown: Expect reboot!\n");
		}
		}

		static struct platform_driver imx2_wdt_driver = {
		.probe = imx2_wdt_probe,
		.remove = __exit_p(imx2_wdt_remove),
		.shutdown = imx2_wdt_shutdown,
		.driver = {
		.name = DRIVER_NAME,
		.owner = THIS_MODULE,
		},
		};

		static int __init imx2_wdt_init(void)
		{
		return platform_driver_probe(&imx2_wdt_driver, imx2_wdt_probe);
		}
		module_init(imx2_wdt_init);

		static void __exit imx2_wdt_exit(void)
		{
		platform_driver_unregister(&imx2_wdt_driver);
		}
		module_exit(imx2_wdt_exit);

		MODULE_AUTHOR("Wolfram Sang");
		MODULE_DESCRIPTION("Watchdog driver for IMX2 and later");
		MODULE_LICENSE("GPL v2");
		MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
		MODULE_ALIAS("platform:" DRIVER_NAME);

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