drivers/watchdog/adx_wdt.c - kernel/common - Git at Google

 /*
  * Copyright (C) 2008-2009 Avionic Design GmbH
  *
  * 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.
  */

 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/io.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
 #include <linux/watchdog.h>

 #define WATCHDOG_NAME "adx-wdt"

 /* register offsets */
 #define	ADX_WDT_CONTROL		0x00
 #define	ADX_WDT_CONTROL_ENABLE	(1 << 0)
 #define	ADX_WDT_CONTROL_nRESET	(1 << 1)
 #define	ADX_WDT_TIMEOUT		0x08

 static struct platform_device *adx_wdt_dev;
 static unsigned long driver_open;

 #define	WDT_STATE_STOP	0
 #define	WDT_STATE_START	1

 struct adx_wdt {
 	void __iomem *base;
 	unsigned long timeout;
 	unsigned int state;
 	unsigned int wake;
 	spinlock_t lock;
 };

 static const struct watchdog_info adx_wdt_info = {
 	.identity = "Avionic Design Xanthos Watchdog",
 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
 };

 static void adx_wdt_start_locked(struct adx_wdt *wdt)
 {
 	u32 ctrl;

 	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
 	ctrl |= ADX_WDT_CONTROL_ENABLE;
 	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
 	wdt->state = WDT_STATE_START;
 }

 static void adx_wdt_start(struct adx_wdt *wdt)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&wdt->lock, flags);
 	adx_wdt_start_locked(wdt);
 	spin_unlock_irqrestore(&wdt->lock, flags);
 }

 static void adx_wdt_stop_locked(struct adx_wdt *wdt)
 {
 	u32 ctrl;

 	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
 	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
 	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
 	wdt->state = WDT_STATE_STOP;
 }

 static void adx_wdt_stop(struct adx_wdt *wdt)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&wdt->lock, flags);
 	adx_wdt_stop_locked(wdt);
 	spin_unlock_irqrestore(&wdt->lock, flags);
 }

 static void adx_wdt_set_timeout(struct adx_wdt *wdt, unsigned long seconds)
 {
 	unsigned long timeout = seconds * 1000;
 	unsigned long flags;
 	unsigned int state;

 	spin_lock_irqsave(&wdt->lock, flags);
 	state = wdt->state;
 	adx_wdt_stop_locked(wdt);
 	writel(timeout, wdt->base + ADX_WDT_TIMEOUT);

 	if (state == WDT_STATE_START)
 		adx_wdt_start_locked(wdt);

 	wdt->timeout = timeout;
 	spin_unlock_irqrestore(&wdt->lock, flags);
 }

 static void adx_wdt_get_timeout(struct adx_wdt *wdt, unsigned long *seconds)
 {
 	*seconds = wdt->timeout / 1000;
 }

 static void adx_wdt_keepalive(struct adx_wdt *wdt)
 {
 	unsigned long flags;

 	spin_lock_irqsave(&wdt->lock, flags);
 	writel(wdt->timeout, wdt->base + ADX_WDT_TIMEOUT);
 	spin_unlock_irqrestore(&wdt->lock, flags);
 }

 static int adx_wdt_open(struct inode *inode, struct file *file)
 {
 	struct adx_wdt *wdt = platform_get_drvdata(adx_wdt_dev);

 	if (test_and_set_bit(0, &driver_open))
 		return -EBUSY;

 	file->private_data = wdt;
 	adx_wdt_set_timeout(wdt, 30);
 	adx_wdt_start(wdt);

 	return nonseekable_open(inode, file);
 }

 static int adx_wdt_release(struct inode *inode, struct file *file)
 {
 	struct adx_wdt *wdt = file->private_data;

 	adx_wdt_stop(wdt);
 	clear_bit(0, &driver_open);

 	return 0;
 }

 static long adx_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct adx_wdt *wdt = file->private_data;
 	void __user *argp = (void __user *)arg;
 	unsigned long __user *p = argp;
 	unsigned long seconds = 0;
 	unsigned int options;
 	long ret = -EINVAL;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		if (copy_to_user(argp, &adx_wdt_info, sizeof(adx_wdt_info)))
 			return -EFAULT;
 		else
 			return 0;

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

 	case WDIOC_KEEPALIVE:
 		adx_wdt_keepalive(wdt);
 		return 0;

 	case WDIOC_SETTIMEOUT:
 		if (get_user(seconds, p))
 			return -EFAULT;

 		adx_wdt_set_timeout(wdt, seconds);

 		/* fallthrough */
 	case WDIOC_GETTIMEOUT:
 		adx_wdt_get_timeout(wdt, &seconds);
 		return put_user(seconds, p);

 	case WDIOC_SETOPTIONS:
 		if (copy_from_user(&options, argp, sizeof(options)))
 			return -EFAULT;

 		if (options & WDIOS_DISABLECARD) {
 			adx_wdt_stop(wdt);
 			ret = 0;
 		}

 		if (options & WDIOS_ENABLECARD) {
 			adx_wdt_start(wdt);
 			ret = 0;
 		}

 		return ret;

 	default:
 		break;
 	}

 	return -ENOTTY;
 }

 static ssize_t adx_wdt_write(struct file *file, const char __user *data,
 		size_t len, loff_t *ppos)
 {
 	struct adx_wdt *wdt = file->private_data;

 	if (len)
 		adx_wdt_keepalive(wdt);

 	return len;
 }

 static const struct file_operations adx_wdt_fops = {
 	.owner = THIS_MODULE,
 	.llseek = no_llseek,
 	.open = adx_wdt_open,
 	.release = adx_wdt_release,
 	.unlocked_ioctl = adx_wdt_ioctl,
 	.write = adx_wdt_write,
 };

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

 static int __devinit adx_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	struct adx_wdt *wdt;
 	int ret = 0;
 	u32 ctrl;

 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt) {
 		dev_err(&pdev->dev, "cannot allocate WDT structure\n");
 		return -ENOMEM;
 	}

 	spin_lock_init(&wdt->lock);

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
 		dev_err(&pdev->dev, "cannot obtain I/O memory region\n");
 		return -ENXIO;
 	}

 	res = devm_request_mem_region(&pdev->dev, res->start,
 			resource_size(res), res->name);
 	if (!res) {
 		dev_err(&pdev->dev, "cannot request I/O memory region\n");
 		return -ENXIO;
 	}

 	wdt->base = devm_ioremap_nocache(&pdev->dev, res->start,
 			resource_size(res));
 	if (!wdt->base) {
 		dev_err(&pdev->dev, "cannot remap I/O memory region\n");
 		return -ENXIO;
 	}

 	/* disable watchdog and reboot on timeout */
 	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
 	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
 	ctrl &= ~ADX_WDT_CONTROL_nRESET;
 	writel(ctrl, wdt->base + ADX_WDT_CONTROL);

 	platform_set_drvdata(pdev, wdt);
 	adx_wdt_dev = pdev;

 	ret = misc_register(&adx_wdt_miscdev);
 	if (ret) {
 		dev_err(&pdev->dev, "cannot register miscdev on minor %d "
 				"(err=%d)\n", WATCHDOG_MINOR, ret);
 		return ret;
 	}

 	return 0;
 }

 static int __devexit adx_wdt_remove(struct platform_device *pdev)
 {
 	struct adx_wdt *wdt = platform_get_drvdata(pdev);

 	misc_deregister(&adx_wdt_miscdev);
 	adx_wdt_stop(wdt);
 	platform_set_drvdata(pdev, NULL);

 	return 0;
 }

 static void adx_wdt_shutdown(struct platform_device *pdev)
 {
 	struct adx_wdt *wdt = platform_get_drvdata(pdev);
 	adx_wdt_stop(wdt);
 }

 #ifdef CONFIG_PM
 static int adx_wdt_suspend(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct adx_wdt *wdt = platform_get_drvdata(pdev);

 	wdt->wake = (wdt->state == WDT_STATE_START) ? 1 : 0;
 	adx_wdt_stop(wdt);

 	return 0;
 }

 static int adx_wdt_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct adx_wdt *wdt = platform_get_drvdata(pdev);

 	if (wdt->wake)
 		adx_wdt_start(wdt);

 	return 0;
 }

 static const struct dev_pm_ops adx_wdt_pm_ops = {
 	.suspend = adx_wdt_suspend,
 	.resume = adx_wdt_resume,
 };

 #  define ADX_WDT_PM_OPS	(&adx_wdt_pm_ops)
 #else
 #  define ADX_WDT_PM_OPS	NULL
 #endif

 static struct platform_driver adx_wdt_driver = {
 	.probe = adx_wdt_probe,
 	.remove = __devexit_p(adx_wdt_remove),
 	.shutdown = adx_wdt_shutdown,
 	.driver = {
 		.name = WATCHDOG_NAME,
 		.owner = THIS_MODULE,
 		.pm = ADX_WDT_PM_OPS,
 	},
 };

 static int __init adx_wdt_init(void)
 {
 	return platform_driver_register(&adx_wdt_driver);
 }

 static void __exit adx_wdt_exit(void)
 {
 	platform_driver_unregister(&adx_wdt_driver);
 }

 module_init(adx_wdt_init);
 module_exit(adx_wdt_exit);

 MODULE_DESCRIPTION("Avionic Design Xanthos Watchdog Driver");
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Thierry Reding <[email protected]>");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* Copyright (C) 2008-2009 Avionic Design GmbH
	*
	* 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.
	*/

	#include <linux/fs.h>
	#include <linux/gfp.h>
	#include <linux/io.h>
	#include <linux/miscdevice.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/types.h>
	#include <linux/uaccess.h>
	#include <linux/watchdog.h>

	#define WATCHDOG_NAME "adx-wdt"

	/* register offsets */
	#define ADX_WDT_CONTROL 0x00
	#define ADX_WDT_CONTROL_ENABLE (1 << 0)
	#define ADX_WDT_CONTROL_nRESET (1 << 1)
	#define ADX_WDT_TIMEOUT 0x08

	static struct platform_device *adx_wdt_dev;
	static unsigned long driver_open;

	#define WDT_STATE_STOP 0
	#define WDT_STATE_START 1

	struct adx_wdt {
	void __iomem *base;
	unsigned long timeout;
	unsigned int state;
	unsigned int wake;
	spinlock_t lock;
	};

	static const struct watchdog_info adx_wdt_info = {
	.identity = "Avionic Design Xanthos Watchdog",
	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING,
	};

	static void adx_wdt_start_locked(struct adx_wdt *wdt)
	{
	u32 ctrl;

	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
	ctrl \|= ADX_WDT_CONTROL_ENABLE;
	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
	wdt->state = WDT_STATE_START;
	}

	static void adx_wdt_start(struct adx_wdt *wdt)
	{
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);
	adx_wdt_start_locked(wdt);
	spin_unlock_irqrestore(&wdt->lock, flags);
	}

	static void adx_wdt_stop_locked(struct adx_wdt *wdt)
	{
	u32 ctrl;

	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
	writel(ctrl, wdt->base + ADX_WDT_CONTROL);
	wdt->state = WDT_STATE_STOP;
	}

	static void adx_wdt_stop(struct adx_wdt *wdt)
	{
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);
	adx_wdt_stop_locked(wdt);
	spin_unlock_irqrestore(&wdt->lock, flags);
	}

	static void adx_wdt_set_timeout(struct adx_wdt *wdt, unsigned long seconds)
	{
	unsigned long timeout = seconds * 1000;
	unsigned long flags;
	unsigned int state;

	spin_lock_irqsave(&wdt->lock, flags);
	state = wdt->state;
	adx_wdt_stop_locked(wdt);
	writel(timeout, wdt->base + ADX_WDT_TIMEOUT);

	if (state == WDT_STATE_START)
	adx_wdt_start_locked(wdt);

	wdt->timeout = timeout;
	spin_unlock_irqrestore(&wdt->lock, flags);
	}

	static void adx_wdt_get_timeout(struct adx_wdt wdt, unsigned long seconds)
	{
	*seconds = wdt->timeout / 1000;
	}

	static void adx_wdt_keepalive(struct adx_wdt *wdt)
	{
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);
	writel(wdt->timeout, wdt->base + ADX_WDT_TIMEOUT);
	spin_unlock_irqrestore(&wdt->lock, flags);
	}

	static int adx_wdt_open(struct inode inode, struct file file)
	{
	struct adx_wdt *wdt = platform_get_drvdata(adx_wdt_dev);

	if (test_and_set_bit(0, &driver_open))
	return -EBUSY;

	file->private_data = wdt;
	adx_wdt_set_timeout(wdt, 30);
	adx_wdt_start(wdt);

	return nonseekable_open(inode, file);
	}

	static int adx_wdt_release(struct inode inode, struct file file)
	{
	struct adx_wdt *wdt = file->private_data;

	adx_wdt_stop(wdt);
	clear_bit(0, &driver_open);

	return 0;
	}

	static long adx_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	{
	struct adx_wdt *wdt = file->private_data;
	void __user argp = (void __user )arg;
	unsigned long __user *p = argp;
	unsigned long seconds = 0;
	unsigned int options;
	long ret = -EINVAL;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	if (copy_to_user(argp, &adx_wdt_info, sizeof(adx_wdt_info)))
	return -EFAULT;
	else
	return 0;

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

	case WDIOC_KEEPALIVE:
	adx_wdt_keepalive(wdt);
	return 0;

	case WDIOC_SETTIMEOUT:
	if (get_user(seconds, p))
	return -EFAULT;

	adx_wdt_set_timeout(wdt, seconds);

	/* fallthrough */
	case WDIOC_GETTIMEOUT:
	adx_wdt_get_timeout(wdt, &seconds);
	return put_user(seconds, p);

	case WDIOC_SETOPTIONS:
	if (copy_from_user(&options, argp, sizeof(options)))
	return -EFAULT;

	if (options & WDIOS_DISABLECARD) {
	adx_wdt_stop(wdt);
	ret = 0;
	}

	if (options & WDIOS_ENABLECARD) {
	adx_wdt_start(wdt);
	ret = 0;
	}

	return ret;

	default:
	break;
	}

	return -ENOTTY;
	}

	static ssize_t adx_wdt_write(struct file file, const char __user data,
	size_t len, loff_t *ppos)
	{
	struct adx_wdt *wdt = file->private_data;

	if (len)
	adx_wdt_keepalive(wdt);

	return len;
	}

	static const struct file_operations adx_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.open = adx_wdt_open,
	.release = adx_wdt_release,
	.unlocked_ioctl = adx_wdt_ioctl,
	.write = adx_wdt_write,
	};

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

	static int __devinit adx_wdt_probe(struct platform_device *pdev)
	{
	struct resource *res;
	struct adx_wdt *wdt;
	int ret = 0;
	u32 ctrl;

	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt) {
	dev_err(&pdev->dev, "cannot allocate WDT structure\n");
	return -ENOMEM;
	}

	spin_lock_init(&wdt->lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
	dev_err(&pdev->dev, "cannot obtain I/O memory region\n");
	return -ENXIO;
	}

	res = devm_request_mem_region(&pdev->dev, res->start,
	resource_size(res), res->name);
	if (!res) {
	dev_err(&pdev->dev, "cannot request I/O memory region\n");
	return -ENXIO;
	}

	wdt->base = devm_ioremap_nocache(&pdev->dev, res->start,
	resource_size(res));
	if (!wdt->base) {
	dev_err(&pdev->dev, "cannot remap I/O memory region\n");
	return -ENXIO;
	}

	/* disable watchdog and reboot on timeout */
	ctrl = readl(wdt->base + ADX_WDT_CONTROL);
	ctrl &= ~ADX_WDT_CONTROL_ENABLE;
	ctrl &= ~ADX_WDT_CONTROL_nRESET;
	writel(ctrl, wdt->base + ADX_WDT_CONTROL);

	platform_set_drvdata(pdev, wdt);
	adx_wdt_dev = pdev;

	ret = misc_register(&adx_wdt_miscdev);
	if (ret) {
	dev_err(&pdev->dev, "cannot register miscdev on minor %d "
	"(err=%d)\n", WATCHDOG_MINOR, ret);
	return ret;
	}

	return 0;
	}

	static int __devexit adx_wdt_remove(struct platform_device *pdev)
	{
	struct adx_wdt *wdt = platform_get_drvdata(pdev);

	misc_deregister(&adx_wdt_miscdev);
	adx_wdt_stop(wdt);
	platform_set_drvdata(pdev, NULL);

	return 0;
	}

	static void adx_wdt_shutdown(struct platform_device *pdev)
	{
	struct adx_wdt *wdt = platform_get_drvdata(pdev);
	adx_wdt_stop(wdt);
	}

	#ifdef CONFIG_PM
	static int adx_wdt_suspend(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct adx_wdt *wdt = platform_get_drvdata(pdev);

	wdt->wake = (wdt->state == WDT_STATE_START) ? 1 : 0;
	adx_wdt_stop(wdt);

	return 0;
	}

	static int adx_wdt_resume(struct device *dev)
	{
	struct platform_device *pdev = to_platform_device(dev);
	struct adx_wdt *wdt = platform_get_drvdata(pdev);

	if (wdt->wake)
	adx_wdt_start(wdt);

	return 0;
	}

	static const struct dev_pm_ops adx_wdt_pm_ops = {
	.suspend = adx_wdt_suspend,
	.resume = adx_wdt_resume,
	};

	# define ADX_WDT_PM_OPS (&adx_wdt_pm_ops)
	#else
	# define ADX_WDT_PM_OPS NULL
	#endif

	static struct platform_driver adx_wdt_driver = {
	.probe = adx_wdt_probe,
	.remove = __devexit_p(adx_wdt_remove),
	.shutdown = adx_wdt_shutdown,
	.driver = {
	.name = WATCHDOG_NAME,
	.owner = THIS_MODULE,
	.pm = ADX_WDT_PM_OPS,
	},
	};

	static int __init adx_wdt_init(void)
	{
	return platform_driver_register(&adx_wdt_driver);
	}

	static void __exit adx_wdt_exit(void)
	{
	platform_driver_unregister(&adx_wdt_driver);
	}

	module_init(adx_wdt_init);
	module_exit(adx_wdt_exit);

	MODULE_DESCRIPTION("Avionic Design Xanthos Watchdog Driver");
	MODULE_LICENSE("GPL v2");
	MODULE_AUTHOR("Thierry Reding <[email protected]>");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);