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Release 4.7 drivers/watchdog/scx200_wdt.c

Directory: drivers/watchdog
/* drivers/char/watchdog/scx200_wdt.c

   National Semiconductor SCx200 Watchdog support

   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>

   Some code taken from:
   National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
   (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>

   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.

   The author(s) of this software shall not be held liable for damages
   of any nature resulting due to the use of this software. This
   software is provided AS-IS with no warranties. */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/scx200.h>
#include <linux/uaccess.h>
#include <linux/io.h>


#define DEBUG

MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
MODULE_LICENSE("GPL");


static int margin = 60;		
/* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");


static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");


static u16 wdto_restart;

static char expect_close;

static unsigned long open_lock;
static DEFINE_SPINLOCK(scx_lock);

/* Bits of the WDCNFG register */

#define W_ENABLE 0x00fa		
/* Enable watchdog */

#define W_DISABLE 0x0000	
/* Disable watchdog */

/* The scaling factor for the timer, this depends on the value of W_ENABLE */

#define W_SCALE (32768/1024)




static void scx200_wdt_ping(void)
{
	spin_lock(&scx_lock);
	outw(wdto_restart, scx200_cb_base + SCx200_WDT_WDTO);
	spin_unlock(&scx_lock);
}


Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel1655.17%133.33%


alan coxalan cox1241.38%133.33%


henrik brix andersenhenrik brix andersen13.45%133.33%


Total29100.00%3100.00%






static void scx200_wdt_update_margin(void)
{
	pr_info("timer margin %d seconds\n", margin);
	wdto_restart = margin * W_SCALE;
}


Contributors
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christer weinigelchrister weinigel1780.95%150.00%


joe perchesjoe perches419.05%150.00%


Total21100.00%2100.00%






static void scx200_wdt_enable(void)
{
	pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart);

	spin_lock(&scx_lock);
	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	outw(W_ENABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	spin_unlock(&scx_lock);

	scx200_wdt_ping();
}


Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel3866.67%125.00%


alan coxalan cox1221.05%125.00%


joe perchesjoe perches47.02%125.00%


henrik brix andersenhenrik brix andersen35.26%125.00%


Total57100.00%4100.00%






static void scx200_wdt_disable(void)
{
	pr_debug("disabling watchdog timer\n");

	spin_lock(&scx_lock);
	outw(0, scx200_cb_base + SCx200_WDT_WDTO);
	outb(SCx200_WDT_WDSTS_WDOVF, scx200_cb_base + SCx200_WDT_WDSTS);
	outw(W_DISABLE, scx200_cb_base + SCx200_WDT_WDCNFG);
	spin_unlock(&scx_lock);
}


Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel3465.38%125.00%


alan coxalan cox1223.08%125.00%


joe perchesjoe perches35.77%125.00%


henrik brix andersenhenrik brix andersen35.77%125.00%


Total52100.00%4100.00%






static int scx200_wdt_open(struct inode *inode, struct file *file)
{
	/* only allow one at a time */
	if (test_and_set_bit(0, &open_lock))
		return -EBUSY;
	scx200_wdt_enable();

	return nonseekable_open(inode, file);
}


Contributors
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christer weinigelchrister weinigel3276.19%133.33%


linus torvaldslinus torvalds614.29%133.33%


alan coxalan cox49.52%133.33%


Total42100.00%3100.00%






static int scx200_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close != 42)
		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	else if (!nowayout)
		scx200_wdt_disable();
	expect_close = 0;
	clear_bit(0, &open_lock);

	return 0;
}


Contributors
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christer weinigelchrister weinigel3874.51%125.00%


wim van sebroeckwim van sebroeck611.76%125.00%


alan coxalan cox47.84%125.00%


joe perchesjoe perches35.88%125.00%


Total51100.00%4100.00%






static int scx200_wdt_notify_sys(struct notifier_block *this,
				      unsigned long code, void *unused)
{
	if (code == SYS_HALT || code == SYS_POWER_OFF)
		if (!nowayout)
			scx200_wdt_disable();

	return NOTIFY_DONE;
}


Contributors
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christer weinigelchrister weinigel40100.00%1100.00%


Total40100.00%1100.00%




static struct notifier_block scx200_wdt_notifier = {
	.notifier_call = scx200_wdt_notify_sys,
};




static ssize_t scx200_wdt_write(struct file *file, const char __user *data,
				     size_t len, loff_t *ppos)
{
	/* check for a magic close character */
	if (len) {
		size_t i;

		scx200_wdt_ping();

		expect_close = 0;
		for (i = 0; i < len; ++i) {
			char c;
			if (get_user(c, data + i))
				return -EFAULT;
			if (c == 'V')
				expect_close = 42;
		}

		return len;
	}

	return 0;
}


Contributors
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christer weinigelchrister weinigel8897.78%133.33%


al viroal viro11.11%133.33%


wim van sebroeckwim van sebroeck11.11%133.33%


Total90100.00%3100.00%






static long scx200_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 = {
		.identity = "NatSemi SCx200 Watchdog",
		.firmware_version = 1,
		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
						WDIOF_MAGICCLOSE,
        };
	int new_margin;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		if (put_user(0, p))
			return -EFAULT;
		return 0;
	case WDIOC_KEEPALIVE:
		scx200_wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, p))
			return -EFAULT;
		if (new_margin < 1)
			return -EINVAL;
		margin = new_margin;
		scx200_wdt_update_margin();
		scx200_wdt_ping();
	case WDIOC_GETTIMEOUT:
		if (put_user(margin, p))
			return -EFAULT;
		return 0;
	default:
		return -ENOTTY;
	}
}


Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel15883.16%120.00%


al viroal viro2312.11%120.00%


wim van sebroeckwim van sebroeck73.68%240.00%


alan coxalan cox21.05%120.00%


Total190100.00%5100.00%




static const struct file_operations scx200_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = scx200_wdt_write,
	.unlocked_ioctl = scx200_wdt_ioctl,
	.open = scx200_wdt_open,
	.release = scx200_wdt_release,
};


static struct miscdevice scx200_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &scx200_wdt_fops,
};




static int __init scx200_wdt_init(void)
{
	int r;

	pr_debug("NatSemi SCx200 Watchdog Driver\n");

	/* check that we have found the configuration block */
	if (!scx200_cb_present())
		return -ENODEV;

	if (!request_region(scx200_cb_base + SCx200_WDT_OFFSET,
			    SCx200_WDT_SIZE,
			    "NatSemi SCx200 Watchdog")) {
		pr_warn("watchdog I/O region busy\n");
		return -EBUSY;
	}

	scx200_wdt_update_margin();
	scx200_wdt_disable();

	r = register_reboot_notifier(&scx200_wdt_notifier);
	if (r) {
		pr_err("unable to register reboot notifier\n");
		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
				SCx200_WDT_SIZE);
		return r;
	}

	r = misc_register(&scx200_wdt_miscdev);
	if (r) {
		unregister_reboot_notifier(&scx200_wdt_notifier);
		release_region(scx200_cb_base + SCx200_WDT_OFFSET,
				SCx200_WDT_SIZE);
		return r;
	}

	return 0;
}


Contributors
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christer weinigelchrister weinigel8467.20%120.00%


alan coxalan cox1814.40%120.00%


joe perchesjoe perches97.20%120.00%


wim van sebroeckwim van sebroeck86.40%120.00%


henrik brix andersenhenrik brix andersen64.80%120.00%


Total125100.00%5100.00%






static void __exit scx200_wdt_cleanup(void)
{
	misc_deregister(&scx200_wdt_miscdev);
	unregister_reboot_notifier(&scx200_wdt_notifier);
	release_region(scx200_cb_base + SCx200_WDT_OFFSET,
		       SCx200_WDT_SIZE);
}


Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel2583.33%133.33%


wim van sebroeckwim van sebroeck413.33%133.33%


henrik brix andersenhenrik brix andersen13.33%133.33%


Total30100.00%3100.00%




module_init(scx200_wdt_init);

module_exit(scx200_wdt_cleanup);

/*
    Local variables:
        compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
        c-basic-offset: 8
    End:
*/

Overall Contributors
PersonTokensPropCommitsCommitProp
christer weinigelchrister weinigel74478.07%14.55%


alan coxalan cox798.29%29.09%


wim van sebroeckwim van sebroeck373.88%836.36%


joe perchesjoe perches313.25%14.55%


al viroal viro242.52%14.55%


henrik brix andersenhenrik brix andersen151.57%14.55%


andrew mortonandrew morton101.05%14.55%


linus torvaldslinus torvalds60.63%14.55%


art haasart haas20.21%14.55%


jean delvarejean delvare10.10%14.55%


olaf heringolaf hering10.10%14.55%


dave jonesdave jones10.10%14.55%


andrey paninandrey panin10.10%14.55%


arjan van de venarjan van de ven10.10%14.55%


Total953100.00%22100.00%

  
Directory: drivers/watchdog



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