drivers/watchdog/max63xx_wdt.c - kernel/skids - Git at Google

 /*
  * drivers/char/watchdog/max63xx_wdt.c
  *
  * Driver for max63{69,70,71,72,73,74} watchdog timers
  *
  * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
  *
  * 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.
  *
  * This driver assumes the watchdog pins are memory mapped (as it is
  * the case for the Arcom Zeus). Should it be connected over GPIOs or
  * another interface, some abstraction will have to be introduced.
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
 #include <linux/init.h>
 #include <linux/bitops.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/device.h>
 #include <linux/slab.h>

 #define DEFAULT_HEARTBEAT 60
 #define MAX_HEARTBEAT     60

 static int heartbeat = DEFAULT_HEARTBEAT;
 static int nowayout  = WATCHDOG_NOWAYOUT;

 /*
  * Memory mapping: a single byte, 3 first lower bits to select bit 3
  * to ping the watchdog.
  */
 #define MAX6369_WDSET	(7 << 0)
 #define MAX6369_WDI   	(1 << 3)

 static DEFINE_SPINLOCK(io_lock);

 static unsigned long wdt_status;
 #define WDT_IN_USE	0
 #define WDT_RUNNING	1
 #define WDT_OK_TO_CLOSE 2

 static int nodelay;
 static struct resource	*wdt_mem;
 static void __iomem	*wdt_base;
 static struct platform_device *max63xx_pdev;

 /*
  * The timeout values used are actually the absolute minimum the chip
  * offers. Typical values on my board are slightly over twice as long
  * (10s setting ends up with a 25s timeout), and can be up to 3 times
  * the nominal setting (according to the datasheet). So please take
  * these values with a grain of salt. Same goes for the initial delay
  * "feature". Only max6373/74 have a few settings without this initial
  * delay (selected with the "nodelay" parameter).
  *
  * I also decided to remove from the tables any timeout smaller than a
  * second, as it looked completly overkill...
  */

 /* Timeouts in second */
 struct max63xx_timeout {
 	u8 wdset;
 	u8 tdelay;
 	u8 twd;
 };

 static struct max63xx_timeout max6369_table[] = {
 	{ 5,  1,  1 },
 	{ 6, 10, 10 },
 	{ 7, 60, 60 },
 	{ },
 };

 static struct max63xx_timeout max6371_table[] = {
 	{ 6, 60,  3 },
 	{ 7, 60, 60 },
 	{ },
 };

 static struct max63xx_timeout max6373_table[] = {
 	{ 2, 60,  1 },
 	{ 5,  0,  1 },
 	{ 1,  3,  3 },
 	{ 7, 60, 10 },
 	{ 6,  0, 10 },
 	{ },
 };

 static struct max63xx_timeout *current_timeout;

 static struct max63xx_timeout *
 max63xx_select_timeout(struct max63xx_timeout *table, int value)
 {
 	while (table->twd) {
 		if (value <= table->twd) {
 			if (nodelay && table->tdelay == 0)
 				return table;

 			if (!nodelay)
 				return table;
 		}

 		table++;
 	}

 	return NULL;
 }

 static void max63xx_wdt_ping(void)
 {
 	u8 val;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);

 	__raw_writeb(val | MAX6369_WDI, wdt_base);
 	__raw_writeb(val & ~MAX6369_WDI, wdt_base);

 	spin_unlock(&io_lock);
 }

 static void max63xx_wdt_enable(struct max63xx_timeout *entry)
 {
 	u8 val;

 	if (test_and_set_bit(WDT_RUNNING, &wdt_status))
 		return;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);
 	val &= ~MAX6369_WDSET;
 	val |= entry->wdset;
 	__raw_writeb(val, wdt_base);

 	spin_unlock(&io_lock);

 	/* check for a edge triggered startup */
 	if (entry->tdelay == 0)
 		max63xx_wdt_ping();
 }

 static void max63xx_wdt_disable(void)
 {
 	u8 val;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);
 	val &= ~MAX6369_WDSET;
 	val |= 3;
 	__raw_writeb(val, wdt_base);

 	spin_unlock(&io_lock);

 	clear_bit(WDT_RUNNING, &wdt_status);
 }

 static int max63xx_wdt_open(struct inode *inode, struct file *file)
 {
 	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
 		return -EBUSY;

 	max63xx_wdt_enable(current_timeout);
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

 	return nonseekable_open(inode, file);
 }

 static ssize_t max63xx_wdt_write(struct file *file, const char *data,
 				 size_t len, loff_t *ppos)
 {
 	if (len) {
 		if (!nowayout) {
 			size_t i;

 			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
 			for (i = 0; i != len; i++) {
 				char c;

 				if (get_user(c, data + i))
 					return -EFAULT;

 				if (c == 'V')
 					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
 			}
 		}

 		max63xx_wdt_ping();
 	}

 	return len;
 }

 static const struct watchdog_info ident = {
 	.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
 	.identity = "max63xx Watchdog",
 };

 static long max63xx_wdt_ioctl(struct file *file, unsigned int cmd,
 			      unsigned long arg)
 {
 	int ret = -ENOTTY;

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		ret = copy_to_user((struct watchdog_info *)arg, &ident,
 				   sizeof(ident)) ? -EFAULT : 0;
 		break;

 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		ret = put_user(0, (int *)arg);
 		break;

 	case WDIOC_KEEPALIVE:
 		max63xx_wdt_ping();
 		ret = 0;
 		break;

 	case WDIOC_GETTIMEOUT:
 		ret = put_user(heartbeat, (int *)arg);
 		break;
 	}
 	return ret;
 }

 static int max63xx_wdt_release(struct inode *inode, struct file *file)
 {
 	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
 		max63xx_wdt_disable();
 	else
 		dev_crit(&max63xx_pdev->dev,
 			 "device closed unexpectedly - timer will not stop\n");

 	clear_bit(WDT_IN_USE, &wdt_status);
 	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

 	return 0;
 }

 static const struct file_operations max63xx_wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= max63xx_wdt_write,
 	.unlocked_ioctl	= max63xx_wdt_ioctl,
 	.open		= max63xx_wdt_open,
 	.release	= max63xx_wdt_release,
 };

 static struct miscdevice max63xx_wdt_miscdev = {
 	.minor	= WATCHDOG_MINOR,
 	.name	= "watchdog",
 	.fops	= &max63xx_wdt_fops,
 };

 static int __devinit max63xx_wdt_probe(struct platform_device *pdev)
 {
 	int ret = 0;
 	int size;
 	struct resource *res;
 	struct device *dev = &pdev->dev;
 	struct max63xx_timeout *table;

 	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;

 	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 		heartbeat = DEFAULT_HEARTBEAT;

 	dev_info(dev, "requesting %ds heartbeat\n", heartbeat);
 	current_timeout = max63xx_select_timeout(table, heartbeat);

 	if (!current_timeout) {
 		dev_err(dev, "unable to satisfy heartbeat request\n");
 		return -EINVAL;
 	}

 	dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
 		 current_timeout->twd, current_timeout->tdelay);

 	heartbeat = current_timeout->twd;

 	max63xx_pdev = pdev;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res == NULL) {
 		dev_err(dev, "failed to get memory region resource\n");
 		return -ENOENT;
 	}

 	size = resource_size(res);
 	wdt_mem = request_mem_region(res->start, size, pdev->name);

 	if (wdt_mem == NULL) {
 		dev_err(dev, "failed to get memory region\n");
 		return -ENOENT;
 	}

 	wdt_base = ioremap(res->start, size);
 	if (!wdt_base) {
 		dev_err(dev, "failed to map memory region\n");
 		ret = -ENOMEM;
 		goto out_request;
 	}

 	ret = misc_register(&max63xx_wdt_miscdev);
 	if (ret < 0) {
 		dev_err(dev, "cannot register misc device\n");
 		goto out_unmap;
 	}

 	return 0;

 out_unmap:
 	iounmap(wdt_base);
 out_request:
 	release_resource(wdt_mem);
 	kfree(wdt_mem);

 	return ret;
 }

 static int __devexit max63xx_wdt_remove(struct platform_device *pdev)
 {
 	misc_deregister(&max63xx_wdt_miscdev);
 	if (wdt_mem) {
 		release_resource(wdt_mem);
 		kfree(wdt_mem);
 		wdt_mem = NULL;
 	}

 	if (wdt_base)
 		iounmap(wdt_base);

 	return 0;
 }

 static struct platform_device_id max63xx_id_table[] = {
 	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
 	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
 	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
 	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
 	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
 	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
 	{ },
 };
 MODULE_DEVICE_TABLE(platform, max63xx_id_table);

 static struct platform_driver max63xx_wdt_driver = {
 	.probe		= max63xx_wdt_probe,
 	.remove		= __devexit_p(max63xx_wdt_remove),
 	.id_table	= max63xx_id_table,
 	.driver		= {
 		.name	= "max63xx_wdt",
 		.owner	= THIS_MODULE,
 	},
 };

 static int __init max63xx_wdt_init(void)
 {
 	return platform_driver_register(&max63xx_wdt_driver);
 }

 static void __exit max63xx_wdt_exit(void)
 {
 	platform_driver_unregister(&max63xx_wdt_driver);
 }

 module_init(max63xx_wdt_init);
 module_exit(max63xx_wdt_exit);

 MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
 MODULE_DESCRIPTION("max63xx Watchdog Driver");

 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat,
 		 "Watchdog heartbeat period in seconds from 1 to "
 		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
 		 __MODULE_STRING(DEFAULT_HEARTBEAT));

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

 module_param(nodelay, int, 0);
 MODULE_PARM_DESC(nodelay,
 		 "Force selection of a timeout setting without initial delay "
 		 "(max6373/74 only, default=0)");

 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* drivers/char/watchdog/max63xx_wdt.c
	*
	* Driver for max63{69,70,71,72,73,74} watchdog timers
	*
	* Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
	*
	* 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.
	*
	* This driver assumes the watchdog pins are memory mapped (as it is
	* the case for the Arcom Zeus). Should it be connected over GPIOs or
	* another interface, some abstraction will have to be introduced.
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/fs.h>
	#include <linux/miscdevice.h>
	#include <linux/watchdog.h>
	#include <linux/init.h>
	#include <linux/bitops.h>
	#include <linux/platform_device.h>
	#include <linux/spinlock.h>
	#include <linux/uaccess.h>
	#include <linux/io.h>
	#include <linux/device.h>
	#include <linux/slab.h>

	#define DEFAULT_HEARTBEAT 60
	#define MAX_HEARTBEAT 60

	static int heartbeat = DEFAULT_HEARTBEAT;
	static int nowayout = WATCHDOG_NOWAYOUT;

	/*
	* Memory mapping: a single byte, 3 first lower bits to select bit 3
	* to ping the watchdog.
	*/
	#define MAX6369_WDSET (7 << 0)
	#define MAX6369_WDI (1 << 3)

	static DEFINE_SPINLOCK(io_lock);

	static unsigned long wdt_status;
	#define WDT_IN_USE 0
	#define WDT_RUNNING 1
	#define WDT_OK_TO_CLOSE 2

	static int nodelay;
	static struct resource *wdt_mem;
	static void __iomem *wdt_base;
	static struct platform_device *max63xx_pdev;

	/*
	* The timeout values used are actually the absolute minimum the chip
	* offers. Typical values on my board are slightly over twice as long
	* (10s setting ends up with a 25s timeout), and can be up to 3 times
	* the nominal setting (according to the datasheet). So please take
	* these values with a grain of salt. Same goes for the initial delay
	* "feature". Only max6373/74 have a few settings without this initial
	* delay (selected with the "nodelay" parameter).
	*
	* I also decided to remove from the tables any timeout smaller than a
	* second, as it looked completly overkill...
	*/

	/* Timeouts in second */
	struct max63xx_timeout {
	u8 wdset;
	u8 tdelay;
	u8 twd;
	};

	static struct max63xx_timeout max6369_table[] = {
	{ 5, 1, 1 },
	{ 6, 10, 10 },
	{ 7, 60, 60 },
	{ },
	};

	static struct max63xx_timeout max6371_table[] = {
	{ 6, 60, 3 },
	{ 7, 60, 60 },
	{ },
	};

	static struct max63xx_timeout max6373_table[] = {
	{ 2, 60, 1 },
	{ 5, 0, 1 },
	{ 1, 3, 3 },
	{ 7, 60, 10 },
	{ 6, 0, 10 },
	{ },
	};

	static struct max63xx_timeout *current_timeout;

	static struct max63xx_timeout *
	max63xx_select_timeout(struct max63xx_timeout *table, int value)
	{
	while (table->twd) {
	if (value <= table->twd) {
	if (nodelay && table->tdelay == 0)
	return table;

	if (!nodelay)
	return table;
	}

	table++;
	}

	return NULL;
	}

	static void max63xx_wdt_ping(void)
	{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);

	__raw_writeb(val \| MAX6369_WDI, wdt_base);
	__raw_writeb(val & ~MAX6369_WDI, wdt_base);

	spin_unlock(&io_lock);
	}

	static void max63xx_wdt_enable(struct max63xx_timeout *entry)
	{
	u8 val;

	if (test_and_set_bit(WDT_RUNNING, &wdt_status))
	return;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val \|= entry->wdset;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);

	/* check for a edge triggered startup */
	if (entry->tdelay == 0)
	max63xx_wdt_ping();
	}

	static void max63xx_wdt_disable(void)
	{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val \|= 3;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);

	clear_bit(WDT_RUNNING, &wdt_status);
	}

	static int max63xx_wdt_open(struct inode inode, struct file file)
	{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	return -EBUSY;

	max63xx_wdt_enable(current_timeout);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return nonseekable_open(inode, file);
	}

	static ssize_t max63xx_wdt_write(struct file file, const char data,
	size_t len, loff_t *ppos)
	{
	if (len) {
	if (!nowayout) {
	size_t i;

	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	for (i = 0; i != len; i++) {
	char c;

	if (get_user(c, data + i))
	return -EFAULT;

	if (c == 'V')
	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	}
	}

	max63xx_wdt_ping();
	}

	return len;
	}

	static const struct watchdog_info ident = {
	.options = WDIOF_MAGICCLOSE \| WDIOF_KEEPALIVEPING,
	.identity = "max63xx Watchdog",
	};

	static long max63xx_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	int ret = -ENOTTY;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	sizeof(ident)) ? -EFAULT : 0;
	break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	ret = put_user(0, (int *)arg);
	break;

	case WDIOC_KEEPALIVE:
	max63xx_wdt_ping();
	ret = 0;
	break;

	case WDIOC_GETTIMEOUT:
	ret = put_user(heartbeat, (int *)arg);
	break;
	}
	return ret;
	}

	static int max63xx_wdt_release(struct inode inode, struct file file)
	{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	max63xx_wdt_disable();
	else
	dev_crit(&max63xx_pdev->dev,
	"device closed unexpectedly - timer will not stop\n");

	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
	}

	static const struct file_operations max63xx_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = max63xx_wdt_write,
	.unlocked_ioctl = max63xx_wdt_ioctl,
	.open = max63xx_wdt_open,
	.release = max63xx_wdt_release,
	};

	static struct miscdevice max63xx_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &max63xx_wdt_fops,
	};

	static int __devinit max63xx_wdt_probe(struct platform_device *pdev)
	{
	int ret = 0;
	int size;
	struct resource *res;
	struct device *dev = &pdev->dev;
	struct max63xx_timeout *table;

	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;

	if (heartbeat < 1 \|\| heartbeat > MAX_HEARTBEAT)
	heartbeat = DEFAULT_HEARTBEAT;

	dev_info(dev, "requesting %ds heartbeat\n", heartbeat);
	current_timeout = max63xx_select_timeout(table, heartbeat);

	if (!current_timeout) {
	dev_err(dev, "unable to satisfy heartbeat request\n");
	return -EINVAL;
	}

	dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
	current_timeout->twd, current_timeout->tdelay);

	heartbeat = current_timeout->twd;

	max63xx_pdev = pdev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
	dev_err(dev, "failed to get memory region resource\n");
	return -ENOENT;
	}

	size = resource_size(res);
	wdt_mem = request_mem_region(res->start, size, pdev->name);

	if (wdt_mem == NULL) {
	dev_err(dev, "failed to get memory region\n");
	return -ENOENT;
	}

	wdt_base = ioremap(res->start, size);
	if (!wdt_base) {
	dev_err(dev, "failed to map memory region\n");
	ret = -ENOMEM;
	goto out_request;
	}

	ret = misc_register(&max63xx_wdt_miscdev);
	if (ret < 0) {
	dev_err(dev, "cannot register misc device\n");
	goto out_unmap;
	}

	return 0;

	out_unmap:
	iounmap(wdt_base);
	out_request:
	release_resource(wdt_mem);
	kfree(wdt_mem);

	return ret;
	}

	static int __devexit max63xx_wdt_remove(struct platform_device *pdev)
	{
	misc_deregister(&max63xx_wdt_miscdev);
	if (wdt_mem) {
	release_resource(wdt_mem);
	kfree(wdt_mem);
	wdt_mem = NULL;
	}

	if (wdt_base)
	iounmap(wdt_base);

	return 0;
	}

	static struct platform_device_id max63xx_id_table[] = {
	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
	{ },
	};
	MODULE_DEVICE_TABLE(platform, max63xx_id_table);

	static struct platform_driver max63xx_wdt_driver = {
	.probe = max63xx_wdt_probe,
	.remove = __devexit_p(max63xx_wdt_remove),
	.id_table = max63xx_id_table,
	.driver = {
	.name = "max63xx_wdt",
	.owner = THIS_MODULE,
	},
	};

	static int __init max63xx_wdt_init(void)
	{
	return platform_driver_register(&max63xx_wdt_driver);
	}

	static void __exit max63xx_wdt_exit(void)
	{
	platform_driver_unregister(&max63xx_wdt_driver);
	}

	module_init(max63xx_wdt_init);
	module_exit(max63xx_wdt_exit);

	MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
	MODULE_DESCRIPTION("max63xx Watchdog Driver");

	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat,
	"Watchdog heartbeat period in seconds from 1 to "
	__MODULE_STRING(MAX_HEARTBEAT) ", default "
	__MODULE_STRING(DEFAULT_HEARTBEAT));

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

	module_param(nodelay, int, 0);
	MODULE_PARM_DESC(nodelay,
	"Force selection of a timeout setting without initial delay "
	"(max6373/74 only, default=0)");

	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);