tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * IndyDog 0.3 A Hardware Watchdog Device for SGI IP22
3 *
4 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>,
5 * All Rights Reserved.
6 *
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.
11 *
12 * based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
13 */
14
15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/fs.h>
22#include <linux/mm.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/notifier.h>
26#include <linux/reboot.h>
27#include <linux/init.h>
28#include <linux/uaccess.h>
29#include <asm/sgi/mc.h>
30
31static unsigned long indydog_alive;
32static DEFINE_SPINLOCK(indydog_lock);
33
34#define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
35
36static bool nowayout = WATCHDOG_NOWAYOUT;
37module_param(nowayout, bool, 0);
38MODULE_PARM_DESC(nowayout,
39 "Watchdog cannot be stopped once started (default="
40 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
41
42static void indydog_start(void)
43{
44 u32 mc_ctrl0;
45
46 spin_lock(&indydog_lock);
47 mc_ctrl0 = sgimc->cpuctrl0;
48 mc_ctrl0 = sgimc->cpuctrl0 | SGIMC_CCTRL0_WDOG;
49 sgimc->cpuctrl0 = mc_ctrl0;
50 spin_unlock(&indydog_lock);
51}
52
53static void indydog_stop(void)
54{
55 u32 mc_ctrl0;
56
57 spin_lock(&indydog_lock);
58
59 mc_ctrl0 = sgimc->cpuctrl0;
60 mc_ctrl0 &= ~SGIMC_CCTRL0_WDOG;
61 sgimc->cpuctrl0 = mc_ctrl0;
62 spin_unlock(&indydog_lock);
63
64 pr_info("Stopped watchdog timer\n");
65}
66
67static void indydog_ping(void)
68{
69 sgimc->watchdogt = 0;
70}
71
72/*
73 * Allow only one person to hold it open
74 */
75static int indydog_open(struct inode *inode, struct file *file)
76{
77 if (test_and_set_bit(0, &indydog_alive))
78 return -EBUSY;
79
80 if (nowayout)
81 __module_get(THIS_MODULE);
82
83 /* Activate timer */
84 indydog_start();
85 indydog_ping();
86
87 pr_info("Started watchdog timer\n");
88
89 return nonseekable_open(inode, file);
90}
91
92static int indydog_release(struct inode *inode, struct file *file)
93{
94 /* Shut off the timer.
95 * Lock it in if it's a module and we defined ...NOWAYOUT */
96 if (!nowayout)
97 indydog_stop(); /* Turn the WDT off */
98 clear_bit(0, &indydog_alive);
99 return 0;
100}
101
102static ssize_t indydog_write(struct file *file, const char *data,
103 size_t len, loff_t *ppos)
104{
105 /* Refresh the timer. */
106 if (len)
107 indydog_ping();
108 return len;
109}
110
111static long indydog_ioctl(struct file *file, unsigned int cmd,
112 unsigned long arg)
113{
114 int options, retval = -EINVAL;
115 static const struct watchdog_info ident = {
116 .options = WDIOF_KEEPALIVEPING,
117 .firmware_version = 0,
118 .identity = "Hardware Watchdog for SGI IP22",
119 };
120
121 switch (cmd) {
122 case WDIOC_GETSUPPORT:
123 if (copy_to_user((struct watchdog_info *)arg,
124 &ident, sizeof(ident)))
125 return -EFAULT;
126 return 0;
127 case WDIOC_GETSTATUS:
128 case WDIOC_GETBOOTSTATUS:
129 return put_user(0, (int *)arg);
130 case WDIOC_SETOPTIONS:
131 {
132 if (get_user(options, (int *)arg))
133 return -EFAULT;
134 if (options & WDIOS_DISABLECARD) {
135 indydog_stop();
136 retval = 0;
137 }
138 if (options & WDIOS_ENABLECARD) {
139 indydog_start();
140 retval = 0;
141 }
142 return retval;
143 }
144 case WDIOC_KEEPALIVE:
145 indydog_ping();
146 return 0;
147 case WDIOC_GETTIMEOUT:
148 return put_user(WATCHDOG_TIMEOUT, (int *)arg);
149 default:
150 return -ENOTTY;
151 }
152}
153
154static int indydog_notify_sys(struct notifier_block *this,
155 unsigned long code, void *unused)
156{
157 if (code == SYS_DOWN || code == SYS_HALT)
158 indydog_stop(); /* Turn the WDT off */
159
160 return NOTIFY_DONE;
161}
162
163static const struct file_operations indydog_fops = {
164 .owner = THIS_MODULE,
165 .llseek = no_llseek,
166 .write = indydog_write,
167 .unlocked_ioctl = indydog_ioctl,
168 .open = indydog_open,
169 .release = indydog_release,
170};
171
172static struct miscdevice indydog_miscdev = {
173 .minor = WATCHDOG_MINOR,
174 .name = "watchdog",
175 .fops = &indydog_fops,
176};
177
178static struct notifier_block indydog_notifier = {
179 .notifier_call = indydog_notify_sys,
180};
181
182static int __init watchdog_init(void)
183{
184 int ret;
185
186 ret = register_reboot_notifier(&indydog_notifier);
187 if (ret) {
188 pr_err("cannot register reboot notifier (err=%d)\n", ret);
189 return ret;
190 }
191
192 ret = misc_register(&indydog_miscdev);
193 if (ret) {
194 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
195 WATCHDOG_MINOR, ret);
196 unregister_reboot_notifier(&indydog_notifier);
197 return ret;
198 }
199
200 pr_info("Hardware Watchdog Timer for SGI IP22: 0.3\n");
201
202 return 0;
203}
204
205static void __exit watchdog_exit(void)
206{
207 misc_deregister(&indydog_miscdev);
208 unregister_reboot_notifier(&indydog_notifier);
209}
210
211module_init(watchdog_init);
212module_exit(watchdog_exit);
213
214MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>");
215MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22");
216MODULE_LICENSE("GPL");
217MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);