2 * Watchdog driver for the SA11x0
4 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
5 * Based on SoftDog driver by Alan Cox <alan@redhat.com>
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
12 * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
13 * warranty for any of this software. This material is provided
14 * "AS-IS" and at no charge.
16 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
18 * 27/11/2000 Initial release
20 #include <linux/config.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/types.h>
24 #include <linux/kernel.h>
26 #include <linux/miscdevice.h>
27 #include <linux/watchdog.h>
28 #include <linux/init.h>
30 #include <asm/hardware.h>
31 #include <asm/bitops.h>
32 #include <asm/uaccess.h>
34 #define OSCR_FREQ 3686400
35 #define SA1100_CLOSE_MAGIC (0x5afc4453)
37 static unsigned long sa1100wdt_users;
38 static int expect_close;
39 static int pre_margin;
40 static int boot_status;
41 #ifdef CONFIG_WATCHDOG_NOWAYOUT
42 static int nowayout = 1;
44 static int nowayout = 0;
48 * Allow only one person to hold it open
50 static int sa1100dog_open(struct inode *inode, struct file *file)
52 if (test_and_set_bit(1,&sa1100wdt_users))
55 /* Activate SA1100 Watchdog timer */
56 OSMR3 = OSCR + pre_margin;
65 * Lock it in if it's a module and we defined ...NOWAYOUT
66 * Oddly, the watchdog can only be enabled, but we can turn off
67 * the interrupt, which appears to prevent the watchdog timing out.
69 static int sa1100dog_release(struct inode *inode, struct file *file)
71 OSMR3 = OSCR + pre_margin;
73 if (expect_close == SA1100_CLOSE_MAGIC) {
76 printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n");
79 clear_bit(1, &sa1100wdt_users);
85 static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
87 /* Can't seek (pwrite) on this device */
88 if (ppos != &file->f_pos)
97 for (i = 0; i != len; i++) {
100 if (get_user(c, data + i))
103 expect_close = SA1100_CLOSE_MAGIC;
106 /* Refresh OSMR3 timer. */
107 OSMR3 = OSCR + pre_margin;
113 static struct watchdog_info ident = {
114 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
115 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
116 .identity = "SA1100 Watchdog",
119 static int sa1100dog_ioctl(struct inode *inode, struct file *file,
120 unsigned int cmd, unsigned long arg)
122 int ret = -ENOIOCTLCMD;
126 case WDIOC_GETSUPPORT:
127 ret = copy_to_user((struct watchdog_info *)arg, &ident,
128 sizeof(ident)) ? -EFAULT : 0;
131 case WDIOC_GETSTATUS:
132 ret = put_user(0, (int *)arg);
135 case WDIOC_GETBOOTSTATUS:
136 ret = put_user(boot_status, (int *)arg);
139 case WDIOC_SETTIMEOUT:
140 ret = get_user(time, (int *)arg);
144 if (time <= 0 || time > 255) {
149 pre_margin = OSCR_FREQ * time;
150 OSMR3 = OSCR + pre_margin;
153 case WDIOC_GETTIMEOUT:
154 ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
157 case WDIOC_KEEPALIVE:
158 OSMR3 = OSCR + pre_margin;
165 static struct file_operations sa1100dog_fops =
167 .owner = THIS_MODULE,
168 .write = sa1100dog_write,
169 .ioctl = sa1100dog_ioctl,
170 .open = sa1100dog_open,
171 .release = sa1100dog_release,
174 static struct miscdevice sa1100dog_miscdev =
176 .minor = WATCHDOG_MINOR,
177 .name = "SA1100 watchdog",
178 .fops = &sa1100dog_fops,
181 static int margin __initdata = 60; /* (secs) Default is 1 minute */
183 static int __init sa1100dog_init(void)
188 * Read the reset status, and save it for later. If
189 * we suspend, RCSR will be cleared, and the watchdog
190 * reset reason will be lost.
192 boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
193 pre_margin = OSCR_FREQ * margin;
195 ret = misc_register(&sa1100dog_miscdev);
197 printk("SA1100 Watchdog Timer: timer margin %d sec\n",
203 static void __exit sa1100dog_exit(void)
205 misc_deregister(&sa1100dog_miscdev);
208 module_init(sa1100dog_init);
209 module_exit(sa1100dog_exit);
211 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
212 MODULE_DESCRIPTION("SA1100 Watchdog");
214 module_param(margin, int, 0);
215 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
217 module_param(nowayout, int, 0);
218 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
220 MODULE_LICENSE("GPL");
221 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);