2 * Watchdog driver for Atmel AT91RM9200 (Thunder)
4 * Copyright (C) 2003 SAN People (Pty) Ltd
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/bitops.h>
13 #include <linux/errno.h>
15 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/miscdevice.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/platform_device.h>
22 #include <linux/types.h>
23 #include <linux/watchdog.h>
24 #include <linux/uaccess.h>
25 #include <mach/at91_st.h>
27 #define WDT_DEFAULT_TIME 5 /* seconds */
28 #define WDT_MAX_TIME 256 /* seconds */
30 static int wdt_time = WDT_DEFAULT_TIME;
31 static int nowayout = WATCHDOG_NOWAYOUT;
33 module_param(wdt_time, int, 0);
34 MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
35 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
37 #ifdef CONFIG_WATCHDOG_NOWAYOUT
38 module_param(nowayout, int, 0);
39 MODULE_PARM_DESC(nowayout,
40 "Watchdog cannot be stopped once started (default="
41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
45 static unsigned long at91wdt_busy;
47 /* ......................................................................... */
50 * Disable the watchdog.
52 static inline void at91_wdt_stop(void)
54 at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
58 * Enable and reset the watchdog.
60 static inline void at91_wdt_start(void)
62 at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN |
63 (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
64 at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
68 * Reload the watchdog timer. (ie, pat the watchdog)
70 static inline void at91_wdt_reload(void)
72 at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
75 /* ......................................................................... */
78 * Watchdog device is opened, and watchdog starts running.
80 static int at91_wdt_open(struct inode *inode, struct file *file)
82 if (test_and_set_bit(0, &at91wdt_busy))
86 return nonseekable_open(inode, file);
90 * Close the watchdog device.
91 * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
94 static int at91_wdt_close(struct inode *inode, struct file *file)
96 /* Disable the watchdog when file is closed */
100 clear_bit(0, &at91wdt_busy);
105 * Change the watchdog time interval.
107 static int at91_wdt_settimeout(int new_time)
110 * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
112 * Since WDV is a 16-bit counter, the maximum period is
113 * 65536 / 256 = 256 seconds.
115 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
118 /* Set new watchdog time. It will be used when
119 at91_wdt_start() is called. */
124 static const struct watchdog_info at91_wdt_info = {
125 .identity = "at91 watchdog",
126 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
130 * Handle commands from user-space.
132 static long at91_wdt_ioctl(struct file *file,
133 unsigned int cmd, unsigned long arg)
135 void __user *argp = (void __user *)arg;
136 int __user *p = argp;
140 case WDIOC_GETSUPPORT:
141 return copy_to_user(argp, &at91_wdt_info,
142 sizeof(at91_wdt_info)) ? -EFAULT : 0;
143 case WDIOC_GETSTATUS:
144 case WDIOC_GETBOOTSTATUS:
145 return put_user(0, p);
146 case WDIOC_SETOPTIONS:
147 if (get_user(new_value, p))
149 if (new_value & WDIOS_DISABLECARD)
151 if (new_value & WDIOS_ENABLECARD)
154 case WDIOC_KEEPALIVE:
155 at91_wdt_reload(); /* pat the watchdog */
157 case WDIOC_SETTIMEOUT:
158 if (get_user(new_value, p))
160 if (at91_wdt_settimeout(new_value))
162 /* Enable new time value */
164 /* Return current value */
165 return put_user(wdt_time, p);
166 case WDIOC_GETTIMEOUT:
167 return put_user(wdt_time, p);
174 * Pat the watchdog whenever device is written to.
176 static ssize_t at91_wdt_write(struct file *file, const char *data,
177 size_t len, loff_t *ppos)
179 at91_wdt_reload(); /* pat the watchdog */
183 /* ......................................................................... */
185 static const struct file_operations at91wdt_fops = {
186 .owner = THIS_MODULE,
188 .unlocked_ioctl = at91_wdt_ioctl,
189 .open = at91_wdt_open,
190 .release = at91_wdt_close,
191 .write = at91_wdt_write,
194 static struct miscdevice at91wdt_miscdev = {
195 .minor = WATCHDOG_MINOR,
197 .fops = &at91wdt_fops,
200 static int __devinit at91wdt_probe(struct platform_device *pdev)
204 if (at91wdt_miscdev.parent)
206 at91wdt_miscdev.parent = &pdev->dev;
208 res = misc_register(&at91wdt_miscdev);
212 printk(KERN_INFO "AT91 Watchdog Timer enabled (%d seconds%s)\n",
213 wdt_time, nowayout ? ", nowayout" : "");
217 static int __devexit at91wdt_remove(struct platform_device *pdev)
221 res = misc_deregister(&at91wdt_miscdev);
223 at91wdt_miscdev.parent = NULL;
228 static void at91wdt_shutdown(struct platform_device *pdev)
235 static int at91wdt_suspend(struct platform_device *pdev, pm_message_t message)
241 static int at91wdt_resume(struct platform_device *pdev)
249 #define at91wdt_suspend NULL
250 #define at91wdt_resume NULL
253 static struct platform_driver at91wdt_driver = {
254 .probe = at91wdt_probe,
255 .remove = __devexit_p(at91wdt_remove),
256 .shutdown = at91wdt_shutdown,
257 .suspend = at91wdt_suspend,
258 .resume = at91wdt_resume,
261 .owner = THIS_MODULE,
265 static int __init at91_wdt_init(void)
267 /* Check that the heartbeat value is within range;
268 if not reset to the default */
269 if (at91_wdt_settimeout(wdt_time)) {
270 at91_wdt_settimeout(WDT_DEFAULT_TIME);
271 pr_info("at91_wdt: wdt_time value must be 1 <= wdt_time <= 256"
272 ", using %d\n", wdt_time);
275 return platform_driver_register(&at91wdt_driver);
278 static void __exit at91_wdt_exit(void)
280 platform_driver_unregister(&at91wdt_driver);
283 module_init(at91_wdt_init);
284 module_exit(at91_wdt_exit);
286 MODULE_AUTHOR("Andrew Victor");
287 MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
288 MODULE_LICENSE("GPL");
289 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
290 MODULE_ALIAS("platform:at91_wdt");