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yaml --- r: 25238 b: refs/heads/master c: 853807f h: refs/heads/master v: v3
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Andrew Victor
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Wim Van Sebroeck
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Apr 2, 2006
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refs/heads/master: c9d1a0b8d52e7539e22f3c3190f8b6e0c80b6cfe | ||
refs/heads/master: 853807fb500a9442d88646b7be92bfa51334f8e8 |
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/* | ||
* Watchdog driver for Atmel AT91RM9200 (Thunder) | ||
* | ||
* Copyright (C) 2003 SAN People (Pty) Ltd | ||
* | ||
* 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. | ||
*/ | ||
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#include <linux/config.h> | ||
#include <linux/errno.h> | ||
#include <linux/fs.h> | ||
#include <linux/init.h> | ||
#include <linux/kernel.h> | ||
#include <linux/miscdevice.h> | ||
#include <linux/module.h> | ||
#include <linux/moduleparam.h> | ||
#include <linux/types.h> | ||
#include <linux/watchdog.h> | ||
#include <asm/bitops.h> | ||
#include <asm/uaccess.h> | ||
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#define WDT_DEFAULT_TIME 5 /* 5 seconds */ | ||
#define WDT_MAX_TIME 256 /* 256 seconds */ | ||
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static int wdt_time = WDT_DEFAULT_TIME; | ||
static int nowayout = WATCHDOG_NOWAYOUT; | ||
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module_param(wdt_time, int, 0); | ||
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")"); | ||
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module_param(nowayout, int, 0); | ||
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | ||
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static unsigned long at91wdt_busy; | ||
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/* ......................................................................... */ | ||
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/* | ||
* Disable the watchdog. | ||
*/ | ||
static void inline at91_wdt_stop(void) | ||
{ | ||
at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN); | ||
} | ||
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/* | ||
* Enable and reset the watchdog. | ||
*/ | ||
static void inline at91_wdt_start(void) | ||
{ | ||
at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV)); | ||
at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | ||
} | ||
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/* | ||
* Reload the watchdog timer. (ie, pat the watchdog) | ||
*/ | ||
static void inline at91_wdt_reload(void) | ||
{ | ||
at91_sys_write(AT91_ST_CR, AT91_ST_WDRST); | ||
} | ||
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/* ......................................................................... */ | ||
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/* | ||
* Watchdog device is opened, and watchdog starts running. | ||
*/ | ||
static int at91_wdt_open(struct inode *inode, struct file *file) | ||
{ | ||
if (test_and_set_bit(0, &at91wdt_busy)) | ||
return -EBUSY; | ||
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at91_wdt_start(); | ||
return nonseekable_open(inode, file); | ||
} | ||
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/* | ||
* Close the watchdog device. | ||
* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also | ||
* disabled. | ||
*/ | ||
static int at91_wdt_close(struct inode *inode, struct file *file) | ||
{ | ||
if (!nowayout) | ||
at91_wdt_stop(); /* Disable the watchdog when file is closed */ | ||
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clear_bit(0, &at91wdt_busy); | ||
return 0; | ||
} | ||
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/* | ||
* Change the watchdog time interval. | ||
*/ | ||
static int at91_wdt_settimeout(int new_time) | ||
{ | ||
/* | ||
* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz | ||
* | ||
* Since WDV is a 16-bit counter, the maximum period is | ||
* 65536 / 0.256 = 256 seconds. | ||
*/ | ||
if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) | ||
return -EINVAL; | ||
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/* Set new watchdog time. It will be used when at91_wdt_start() is called. */ | ||
wdt_time = new_time; | ||
return 0; | ||
} | ||
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static struct watchdog_info at91_wdt_info = { | ||
.identity = "at91 watchdog", | ||
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | ||
}; | ||
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/* | ||
* Handle commands from user-space. | ||
*/ | ||
static int at91_wdt_ioctl(struct inode *inode, struct file *file, | ||
unsigned int cmd, unsigned long arg) | ||
{ | ||
void __user *argp = (void __user *)arg; | ||
int __user *p = argp; | ||
int new_value; | ||
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switch(cmd) { | ||
case WDIOC_KEEPALIVE: | ||
at91_wdt_reload(); /* pat the watchdog */ | ||
return 0; | ||
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case WDIOC_GETSUPPORT: | ||
return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0; | ||
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case WDIOC_SETTIMEOUT: | ||
if (get_user(new_value, p)) | ||
return -EFAULT; | ||
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if (at91_wdt_settimeout(new_value)) | ||
return -EINVAL; | ||
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/* Enable new time value */ | ||
at91_wdt_start(); | ||
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/* Return current value */ | ||
return put_user(wdt_time, p); | ||
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case WDIOC_GETTIMEOUT: | ||
return put_user(wdt_time, p); | ||
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case WDIOC_GETSTATUS: | ||
case WDIOC_GETBOOTSTATUS: | ||
return put_user(0, p); | ||
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case WDIOC_SETOPTIONS: | ||
if (get_user(new_value, p)) | ||
return -EFAULT; | ||
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if (new_value & WDIOS_DISABLECARD) | ||
at91_wdt_stop(); | ||
if (new_value & WDIOS_ENABLECARD) | ||
at91_wdt_start(); | ||
return 0; | ||
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default: | ||
return -ENOIOCTLCMD; | ||
} | ||
} | ||
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/* | ||
* Pat the watchdog whenever device is written to. | ||
*/ | ||
static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) | ||
{ | ||
at91_wdt_reload(); /* pat the watchdog */ | ||
return len; | ||
} | ||
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/* ......................................................................... */ | ||
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static struct file_operations at91wdt_fops = { | ||
.owner = THIS_MODULE, | ||
.llseek = no_llseek, | ||
.ioctl = at91_wdt_ioctl, | ||
.open = at91_wdt_open, | ||
.release = at91_wdt_close, | ||
.write = at91_wdt_write, | ||
}; | ||
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static struct miscdevice at91wdt_miscdev = { | ||
.minor = WATCHDOG_MINOR, | ||
.name = "watchdog", | ||
.fops = &at91wdt_fops, | ||
}; | ||
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static int __init at91_wdt_init(void) | ||
{ | ||
int res; | ||
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/* Check that the heartbeat value is within range; if not reset to the default */ | ||
if (at91_wdt_settimeout(wdt_time)) { | ||
at91_wdt_settimeout(WDT_DEFAULT_TIME); | ||
printk(KERN_INFO "at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time); | ||
} | ||
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res = misc_register(&at91wdt_miscdev); | ||
if (res) | ||
return res; | ||
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printk("AT91 Watchdog Timer enabled (%d seconds, nowayout=%d)\n", wdt_time, nowayout); | ||
return 0; | ||
} | ||
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static void __exit at91_wdt_exit(void) | ||
{ | ||
misc_deregister(&at91wdt_miscdev); | ||
} | ||
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module_init(at91_wdt_init); | ||
module_exit(at91_wdt_exit); | ||
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MODULE_AUTHOR("Andrew Victor"); | ||
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200"); | ||
MODULE_LICENSE("GPL"); | ||
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |