drivers/watchdog/mpc8xxx_wdt.c - kernel/common - Git at Google

 /*
  * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
  *
  * Authors: Dave Updegraff <[email protected]>
  * 	    Kumar Gala <[email protected]>
  * 		Attribution: from 83xx_wst: Florian Schirmer <[email protected]>
  * 				..and from sc520_wdt
  * Copyright (c) 2008  MontaVista Software, Inc.
  *                     Anton Vorontsov <[email protected]>
  *
  * Note: it appears that you can only actually ENABLE or DISABLE the thing
  * once after POR. Once enabled, you cannot disable, and vice versa.
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
  * Free Software Foundation;  either version 2 of the  License, or (at your
  * option) any later version.
  */

 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/timer.h>
 #include <linux/miscdevice.h>
 #include <linux/of_platform.h>
 #include <linux/module.h>
 #include <linux/watchdog.h>
 #include <linux/io.h>
 #include <linux/uaccess.h>
 #include <sysdev/fsl_soc.h>

 struct mpc8xxx_wdt {
 	__be32 res0;
 	__be32 swcrr; /* System watchdog control register */
 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
 	__be32 swcnr; /* System watchdog count register */
 	u8 res1[2];
 	__be16 swsrr; /* System watchdog service register */
 	u8 res2[0xF0];
 };

 struct mpc8xxx_wdt_type {
 	int prescaler;
 	bool hw_enabled;
 };

 static struct mpc8xxx_wdt __iomem *wd_base;
 static int mpc8xxx_wdt_init_late(void);

 static u16 timeout = 0xffff;
 module_param(timeout, ushort, 0);
 MODULE_PARM_DESC(timeout,
 	"Watchdog timeout in ticks. (0<timeout<65536, default=65535)");

 static int reset = 1;
 module_param(reset, bool, 0);
 MODULE_PARM_DESC(reset,
 	"Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");

 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) ")");

 /*
  * We always prescale, but if someone really doesn't want to they can set this
  * to 0
  */
 static int prescale = 1;
 static unsigned int timeout_sec;

 static unsigned long wdt_is_open;
 static DEFINE_SPINLOCK(wdt_spinlock);

 static void mpc8xxx_wdt_keepalive(void)
 {
 	/* Ping the WDT */
 	spin_lock(&wdt_spinlock);
 	out_be16(&wd_base->swsrr, 0x556c);
 	out_be16(&wd_base->swsrr, 0xaa39);
 	spin_unlock(&wdt_spinlock);
 }

 static void mpc8xxx_wdt_timer_ping(unsigned long arg);
 static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);

 static void mpc8xxx_wdt_timer_ping(unsigned long arg)
 {
 	mpc8xxx_wdt_keepalive();
 	/* We're pinging it twice faster than needed, just to be sure. */
 	mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
 }

 static void mpc8xxx_wdt_pr_warn(const char *msg)
 {
 	pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
 		reset ? "reset" : "machine check exception");
 }

 static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf,
 				 size_t count, loff_t *ppos)
 {
 	if (count)
 		mpc8xxx_wdt_keepalive();
 	return count;
 }

 static int mpc8xxx_wdt_open(struct inode *inode, struct file *file)
 {
 	u32 tmp = SWCRR_SWEN;
 	if (test_and_set_bit(0, &wdt_is_open))
 		return -EBUSY;

 	/* Once we start the watchdog we can't stop it */
 	if (nowayout)
 		__module_get(THIS_MODULE);

 	/* Good, fire up the show */
 	if (prescale)
 		tmp |= SWCRR_SWPR;
 	if (reset)
 		tmp |= SWCRR_SWRI;

 	tmp |= timeout << 16;

 	out_be32(&wd_base->swcrr, tmp);

 	del_timer_sync(&wdt_timer);

 	return nonseekable_open(inode, file);
 }

 static int mpc8xxx_wdt_release(struct inode *inode, struct file *file)
 {
 	if (!nowayout)
 		mpc8xxx_wdt_timer_ping(0);
 	else
 		mpc8xxx_wdt_pr_warn("watchdog closed");
 	clear_bit(0, &wdt_is_open);
 	return 0;
 }

 static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd,
 							unsigned long arg)
 {
 	void __user *argp = (void __user *)arg;
 	int __user *p = argp;
 	static const struct watchdog_info ident = {
 		.options = WDIOF_KEEPALIVEPING,
 		.firmware_version = 1,
 		.identity = "MPC8xxx",
 	};

 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
 	case WDIOC_GETSTATUS:
 	case WDIOC_GETBOOTSTATUS:
 		return put_user(0, p);
 	case WDIOC_KEEPALIVE:
 		mpc8xxx_wdt_keepalive();
 		return 0;
 	case WDIOC_GETTIMEOUT:
 		return put_user(timeout_sec, p);
 	default:
 		return -ENOTTY;
 	}
 }

 static const struct file_operations mpc8xxx_wdt_fops = {
 	.owner		= THIS_MODULE,
 	.llseek		= no_llseek,
 	.write		= mpc8xxx_wdt_write,
 	.unlocked_ioctl	= mpc8xxx_wdt_ioctl,
 	.open		= mpc8xxx_wdt_open,
 	.release	= mpc8xxx_wdt_release,
 };

 static struct miscdevice mpc8xxx_wdt_miscdev = {
 	.minor	= WATCHDOG_MINOR,
 	.name	= "watchdog",
 	.fops	= &mpc8xxx_wdt_fops,
 };

 static int __devinit mpc8xxx_wdt_probe(struct platform_device *ofdev,
 				       const struct of_device_id *match)
 {
 	int ret;
 	struct device_node *np = ofdev->dev.of_node;
 	struct mpc8xxx_wdt_type *wdt_type = match->data;
 	u32 freq = fsl_get_sys_freq();
 	bool enabled;

 	if (!freq || freq == -1)
 		return -EINVAL;

 	wd_base = of_iomap(np, 0);
 	if (!wd_base)
 		return -ENOMEM;

 	enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
 	if (!enabled && wdt_type->hw_enabled) {
 		pr_info("mpc8xxx_wdt: could not be enabled in software\n");
 		ret = -ENOSYS;
 		goto err_unmap;
 	}

 	/* Calculate the timeout in seconds */
 	if (prescale)
 		timeout_sec = (timeout * wdt_type->prescaler) / freq;
 	else
 		timeout_sec = timeout / freq;

 #ifdef MODULE
 	ret = mpc8xxx_wdt_init_late();
 	if (ret)
 		goto err_unmap;
 #endif

 	pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
 		"(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
 		timeout_sec);

 	/*
 	 * If the watchdog was previously enabled or we're running on
 	 * MPC8xxx, we should ping the wdt from the kernel until the
 	 * userspace handles it.
 	 */
 	if (enabled)
 		mpc8xxx_wdt_timer_ping(0);
 	return 0;
 err_unmap:
 	iounmap(wd_base);
 	wd_base = NULL;
 	return ret;
 }

 static int __devexit mpc8xxx_wdt_remove(struct platform_device *ofdev)
 {
 	mpc8xxx_wdt_pr_warn("watchdog removed");
 	del_timer_sync(&wdt_timer);
 	misc_deregister(&mpc8xxx_wdt_miscdev);
 	iounmap(wd_base);

 	return 0;
 }

 static const struct of_device_id mpc8xxx_wdt_match[] = {
 	{
 		.compatible = "mpc83xx_wdt",
 		.data = &(struct mpc8xxx_wdt_type) {
 			.prescaler = 0x10000,
 		},
 	},
 	{
 		.compatible = "fsl,mpc8610-wdt",
 		.data = &(struct mpc8xxx_wdt_type) {
 			.prescaler = 0x10000,
 			.hw_enabled = true,
 		},
 	},
 	{
 		.compatible = "fsl,mpc823-wdt",
 		.data = &(struct mpc8xxx_wdt_type) {
 			.prescaler = 0x800,
 		},
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);

 static struct of_platform_driver mpc8xxx_wdt_driver = {
 	.probe		= mpc8xxx_wdt_probe,
 	.remove		= __devexit_p(mpc8xxx_wdt_remove),
 	.driver = {
 		.name = "mpc8xxx_wdt",
 		.owner = THIS_MODULE,
 		.of_match_table = mpc8xxx_wdt_match,
 	},
 };

 /*
  * We do wdt initialization in two steps: arch_initcall probes the wdt
  * very early to start pinging the watchdog (misc devices are not yet
  * available), and later module_init() just registers the misc device.
  */
 static int mpc8xxx_wdt_init_late(void)
 {
 	int ret;

 	if (!wd_base)
 		return -ENODEV;

 	ret = misc_register(&mpc8xxx_wdt_miscdev);
 	if (ret) {
 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
 			WATCHDOG_MINOR, ret);
 		return ret;
 	}
 	return 0;
 }
 #ifndef MODULE
 module_init(mpc8xxx_wdt_init_late);
 #endif

 static int __init mpc8xxx_wdt_init(void)
 {
 	return of_register_platform_driver(&mpc8xxx_wdt_driver);
 }
 arch_initcall(mpc8xxx_wdt_init);

 static void __exit mpc8xxx_wdt_exit(void)
 {
 	of_unregister_platform_driver(&mpc8xxx_wdt_driver);
 }
 module_exit(mpc8xxx_wdt_exit);

 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
 		   "uProcessors");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
	/*
	* mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
	*
	* Authors: Dave Updegraff <[email protected]>
	* Kumar Gala <[email protected]>
	* Attribution: from 83xx_wst: Florian Schirmer <[email protected]>
	* ..and from sc520_wdt
	* Copyright (c) 2008 MontaVista Software, Inc.
	* Anton Vorontsov <[email protected]>
	*
	* Note: it appears that you can only actually ENABLE or DISABLE the thing
	* once after POR. Once enabled, you cannot disable, and vice versa.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the
	* Free Software Foundation; either version 2 of the License, or (at your
	* option) any later version.
	*/

	#include <linux/fs.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/timer.h>
	#include <linux/miscdevice.h>
	#include <linux/of_platform.h>
	#include <linux/module.h>
	#include <linux/watchdog.h>
	#include <linux/io.h>
	#include <linux/uaccess.h>
	#include <sysdev/fsl_soc.h>

	struct mpc8xxx_wdt {
	__be32 res0;
	__be32 swcrr; /* System watchdog control register */
	#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
	#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
	#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
	#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
	__be32 swcnr; /* System watchdog count register */
	u8 res1[2];
	__be16 swsrr; /* System watchdog service register */
	u8 res2[0xF0];
	};

	struct mpc8xxx_wdt_type {
	int prescaler;
	bool hw_enabled;
	};

	static struct mpc8xxx_wdt __iomem *wd_base;
	static int mpc8xxx_wdt_init_late(void);

	static u16 timeout = 0xffff;
	module_param(timeout, ushort, 0);
	MODULE_PARM_DESC(timeout,
	"Watchdog timeout in ticks. (0<timeout<65536, default=65535)");

	static int reset = 1;
	module_param(reset, bool, 0);
	MODULE_PARM_DESC(reset,
	"Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");

	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) ")");

	/*
	* We always prescale, but if someone really doesn't want to they can set this
	* to 0
	*/
	static int prescale = 1;
	static unsigned int timeout_sec;

	static unsigned long wdt_is_open;
	static DEFINE_SPINLOCK(wdt_spinlock);

	static void mpc8xxx_wdt_keepalive(void)
	{
	/* Ping the WDT */
	spin_lock(&wdt_spinlock);
	out_be16(&wd_base->swsrr, 0x556c);
	out_be16(&wd_base->swsrr, 0xaa39);
	spin_unlock(&wdt_spinlock);
	}

	static void mpc8xxx_wdt_timer_ping(unsigned long arg);
	static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);

	static void mpc8xxx_wdt_timer_ping(unsigned long arg)
	{
	mpc8xxx_wdt_keepalive();
	/* We're pinging it twice faster than needed, just to be sure. */
	mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
	}

	static void mpc8xxx_wdt_pr_warn(const char *msg)
	{
	pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
	reset ? "reset" : "machine check exception");
	}

	static ssize_t mpc8xxx_wdt_write(struct file file, const char __user buf,
	size_t count, loff_t *ppos)
	{
	if (count)
	mpc8xxx_wdt_keepalive();
	return count;
	}

	static int mpc8xxx_wdt_open(struct inode inode, struct file file)
	{
	u32 tmp = SWCRR_SWEN;
	if (test_and_set_bit(0, &wdt_is_open))
	return -EBUSY;

	/* Once we start the watchdog we can't stop it */
	if (nowayout)
	__module_get(THIS_MODULE);

	/* Good, fire up the show */
	if (prescale)
	tmp \|= SWCRR_SWPR;
	if (reset)
	tmp \|= SWCRR_SWRI;

	tmp \|= timeout << 16;

	out_be32(&wd_base->swcrr, tmp);

	del_timer_sync(&wdt_timer);

	return nonseekable_open(inode, file);
	}

	static int mpc8xxx_wdt_release(struct inode inode, struct file file)
	{
	if (!nowayout)
	mpc8xxx_wdt_timer_ping(0);
	else
	mpc8xxx_wdt_pr_warn("watchdog closed");
	clear_bit(0, &wdt_is_open);
	return 0;
	}

	static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd,
	unsigned long arg)
	{
	void __user argp = (void __user )arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
	.options = WDIOF_KEEPALIVEPING,
	.firmware_version = 1,
	.identity = "MPC8xxx",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
	return put_user(0, p);
	case WDIOC_KEEPALIVE:
	mpc8xxx_wdt_keepalive();
	return 0;
	case WDIOC_GETTIMEOUT:
	return put_user(timeout_sec, p);
	default:
	return -ENOTTY;
	}
	}

	static const struct file_operations mpc8xxx_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = mpc8xxx_wdt_write,
	.unlocked_ioctl = mpc8xxx_wdt_ioctl,
	.open = mpc8xxx_wdt_open,
	.release = mpc8xxx_wdt_release,
	};

	static struct miscdevice mpc8xxx_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &mpc8xxx_wdt_fops,
	};

	static int __devinit mpc8xxx_wdt_probe(struct platform_device *ofdev,
	const struct of_device_id *match)
	{
	int ret;
	struct device_node *np = ofdev->dev.of_node;
	struct mpc8xxx_wdt_type *wdt_type = match->data;
	u32 freq = fsl_get_sys_freq();
	bool enabled;

	if (!freq \|\| freq == -1)
	return -EINVAL;

	wd_base = of_iomap(np, 0);
	if (!wd_base)
	return -ENOMEM;

	enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
	if (!enabled && wdt_type->hw_enabled) {
	pr_info("mpc8xxx_wdt: could not be enabled in software\n");
	ret = -ENOSYS;
	goto err_unmap;
	}

	/* Calculate the timeout in seconds */
	if (prescale)
	timeout_sec = (timeout * wdt_type->prescaler) / freq;
	else
	timeout_sec = timeout / freq;

	#ifdef MODULE
	ret = mpc8xxx_wdt_init_late();
	if (ret)
	goto err_unmap;
	#endif

	pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
	"(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
	timeout_sec);

	/*
	* If the watchdog was previously enabled or we're running on
	* MPC8xxx, we should ping the wdt from the kernel until the
	* userspace handles it.
	*/
	if (enabled)
	mpc8xxx_wdt_timer_ping(0);
	return 0;
	err_unmap:
	iounmap(wd_base);
	wd_base = NULL;
	return ret;
	}

	static int __devexit mpc8xxx_wdt_remove(struct platform_device *ofdev)
	{
	mpc8xxx_wdt_pr_warn("watchdog removed");
	del_timer_sync(&wdt_timer);
	misc_deregister(&mpc8xxx_wdt_miscdev);
	iounmap(wd_base);

	return 0;
	}

	static const struct of_device_id mpc8xxx_wdt_match[] = {
	{
	.compatible = "mpc83xx_wdt",
	.data = &(struct mpc8xxx_wdt_type) {
	.prescaler = 0x10000,
	},
	},
	{
	.compatible = "fsl,mpc8610-wdt",
	.data = &(struct mpc8xxx_wdt_type) {
	.prescaler = 0x10000,
	.hw_enabled = true,
	},
	},
	{
	.compatible = "fsl,mpc823-wdt",
	.data = &(struct mpc8xxx_wdt_type) {
	.prescaler = 0x800,
	},
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);

	static struct of_platform_driver mpc8xxx_wdt_driver = {
	.probe = mpc8xxx_wdt_probe,
	.remove = __devexit_p(mpc8xxx_wdt_remove),
	.driver = {
	.name = "mpc8xxx_wdt",
	.owner = THIS_MODULE,
	.of_match_table = mpc8xxx_wdt_match,
	},
	};

	/*
	* We do wdt initialization in two steps: arch_initcall probes the wdt
	* very early to start pinging the watchdog (misc devices are not yet
	* available), and later module_init() just registers the misc device.
	*/
	static int mpc8xxx_wdt_init_late(void)
	{
	int ret;

	if (!wd_base)
	return -ENODEV;

	ret = misc_register(&mpc8xxx_wdt_miscdev);
	if (ret) {
	pr_err("cannot register miscdev on minor=%d (err=%d)\n",
	WATCHDOG_MINOR, ret);
	return ret;
	}
	return 0;
	}
	#ifndef MODULE
	module_init(mpc8xxx_wdt_init_late);
	#endif

	static int __init mpc8xxx_wdt_init(void)
	{
	return of_register_platform_driver(&mpc8xxx_wdt_driver);
	}
	arch_initcall(mpc8xxx_wdt_init);

	static void __exit mpc8xxx_wdt_exit(void)
	{
	of_unregister_platform_driver(&mpc8xxx_wdt_driver);
	}
	module_exit(mpc8xxx_wdt_exit);

	MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
	MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
	"uProcessors");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);