2 * Watchdog driver for the SA11x0/PXA2xx
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 #ifdef CONFIG_ARCH_PXA
31 #include <asm/arch/pxa-regs.h>
34 #include <asm/hardware.h>
35 #include <asm/bitops.h>
36 #include <asm/uaccess.h>
38 #define OSCR_FREQ CLOCK_TICK_RATE
39 #define SA1100_CLOSE_MAGIC (0x5afc4453)
41 static unsigned long sa1100wdt_users;
42 static int expect_close;
43 static int pre_margin;
44 static int boot_status;
45 #ifdef CONFIG_WATCHDOG_NOWAYOUT
46 static int nowayout = 1;
48 static int nowayout = 0;
52 * Allow only one person to hold it open
54 static int sa1100dog_open(struct inode *inode, struct file *file)
56 nonseekable_open(inode, file);
57 if (test_and_set_bit(1,&sa1100wdt_users))
60 /* Activate SA1100 Watchdog timer */
61 OSMR3 = OSCR + pre_margin;
70 * Lock it in if it's a module and we defined ...NOWAYOUT
71 * Oddly, the watchdog can only be enabled, but we can turn off
72 * the interrupt, which appears to prevent the watchdog timing out.
74 static int sa1100dog_release(struct inode *inode, struct file *file)
76 OSMR3 = OSCR + pre_margin;
78 if (expect_close == SA1100_CLOSE_MAGIC) {
81 printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n");
84 clear_bit(1, &sa1100wdt_users);
90 static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
98 for (i = 0; i != len; i++) {
101 if (get_user(c, data + i))
104 expect_close = SA1100_CLOSE_MAGIC;
107 /* Refresh OSMR3 timer. */
108 OSMR3 = OSCR + pre_margin;
114 static struct watchdog_info ident = {
115 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
116 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
117 .identity = "SA1100 Watchdog",
120 static int sa1100dog_ioctl(struct inode *inode, struct file *file,
121 unsigned int cmd, unsigned long arg)
123 int ret = -ENOIOCTLCMD;
127 case WDIOC_GETSUPPORT:
128 ret = copy_to_user((struct watchdog_info *)arg, &ident,
129 sizeof(ident)) ? -EFAULT : 0;
132 case WDIOC_GETSTATUS:
133 ret = put_user(0, (int *)arg);
136 case WDIOC_GETBOOTSTATUS:
137 ret = put_user(boot_status, (int *)arg);
140 case WDIOC_SETTIMEOUT:
141 ret = get_user(time, (int *)arg);
145 if (time <= 0 || time > 255) {
150 pre_margin = OSCR_FREQ * time;
151 OSMR3 = OSCR + pre_margin;
154 case WDIOC_GETTIMEOUT:
155 ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
158 case WDIOC_KEEPALIVE:
159 OSMR3 = OSCR + pre_margin;
166 static struct file_operations sa1100dog_fops =
168 .owner = THIS_MODULE,
170 .write = sa1100dog_write,
171 .ioctl = sa1100dog_ioctl,
172 .open = sa1100dog_open,
173 .release = sa1100dog_release,
176 static struct miscdevice sa1100dog_miscdev =
178 .minor = WATCHDOG_MINOR,
179 .name = "SA1100/PXA2xx watchdog",
180 .fops = &sa1100dog_fops,
183 static int margin __initdata = 60; /* (secs) Default is 1 minute */
185 static int __init sa1100dog_init(void)
190 * Read the reset status, and save it for later. If
191 * we suspend, RCSR will be cleared, and the watchdog
192 * reset reason will be lost.
194 boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
195 pre_margin = OSCR_FREQ * margin;
197 ret = misc_register(&sa1100dog_miscdev);
199 printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
205 static void __exit sa1100dog_exit(void)
207 misc_deregister(&sa1100dog_miscdev);
210 module_init(sa1100dog_init);
211 module_exit(sa1100dog_exit);
213 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
214 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
216 module_param(margin, int, 0);
217 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
219 module_param(nowayout, int, 0);
220 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
222 MODULE_LICENSE("GPL");
223 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);