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@lxorguk.ukuu.org.uk>
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
21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/types.h>
26 #include <linux/kernel.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/init.h>
31 #include <linux/bitops.h>
32 #include <linux/uaccess.h>
33 #include <linux/timex.h>
35 #ifdef CONFIG_ARCH_PXA
36 #include <mach/regs-ost.h>
39 #include <mach/reset.h>
40 #include <mach/hardware.h>
42 static unsigned long oscr_freq;
43 static unsigned long sa1100wdt_users;
44 static unsigned int pre_margin;
45 static int boot_status;
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;
60 return nonseekable_open(inode, file);
64 * The watchdog cannot be disabled.
66 * Previous comments suggested that turning off the interrupt by
67 * clearing OIER[E3] would prevent the watchdog timing out but this
68 * does not appear to be true (at least on the PXA255).
70 static int sa1100dog_release(struct inode *inode, struct file *file)
72 pr_crit("Device closed - timer will not stop\n");
73 clear_bit(1, &sa1100wdt_users);
77 static ssize_t sa1100dog_write(struct file *file, const char __user *data,
78 size_t len, loff_t *ppos)
81 /* Refresh OSMR3 timer. */
82 OSMR3 = OSCR + pre_margin;
86 static const struct watchdog_info ident = {
87 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT
88 | WDIOF_KEEPALIVEPING,
89 .identity = "SA1100/PXA255 Watchdog",
90 .firmware_version = 1,
93 static long sa1100dog_ioctl(struct file *file, unsigned int cmd,
98 void __user *argp = (void __user *)arg;
102 case WDIOC_GETSUPPORT:
103 ret = copy_to_user(argp, &ident,
104 sizeof(ident)) ? -EFAULT : 0;
107 case WDIOC_GETSTATUS:
108 ret = put_user(0, p);
111 case WDIOC_GETBOOTSTATUS:
112 ret = put_user(boot_status, p);
115 case WDIOC_KEEPALIVE:
116 OSMR3 = OSCR + pre_margin;
120 case WDIOC_SETTIMEOUT:
121 ret = get_user(time, p);
125 if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) {
130 pre_margin = oscr_freq * time;
131 OSMR3 = OSCR + pre_margin;
134 case WDIOC_GETTIMEOUT:
135 ret = put_user(pre_margin / oscr_freq, p);
141 static const struct file_operations sa1100dog_fops = {
142 .owner = THIS_MODULE,
144 .write = sa1100dog_write,
145 .unlocked_ioctl = sa1100dog_ioctl,
146 .open = sa1100dog_open,
147 .release = sa1100dog_release,
150 static struct miscdevice sa1100dog_miscdev = {
151 .minor = WATCHDOG_MINOR,
153 .fops = &sa1100dog_fops,
156 static int margin __initdata = 60; /* (secs) Default is 1 minute */
158 static int __init sa1100dog_init(void)
162 oscr_freq = get_clock_tick_rate();
165 * Read the reset status, and save it for later. If
166 * we suspend, RCSR will be cleared, and the watchdog
167 * reset reason will be lost.
169 boot_status = (reset_status & RESET_STATUS_WATCHDOG) ?
171 pre_margin = oscr_freq * margin;
173 ret = misc_register(&sa1100dog_miscdev);
175 pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
180 static void __exit sa1100dog_exit(void)
182 misc_deregister(&sa1100dog_miscdev);
185 module_init(sa1100dog_init);
186 module_exit(sa1100dog_exit);
188 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
189 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
191 module_param(margin, int, 0);
192 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
194 MODULE_LICENSE("GPL");
195 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);