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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 | |
31 | static unsigned long indydog_alive; |
32 | static DEFINE_SPINLOCK(indydog_lock); |
33 | |
34 | #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */ |
35 | |
36 | static bool nowayout = WATCHDOG_NOWAYOUT; |
37 | module_param(nowayout, bool, 0); |
38 | MODULE_PARM_DESC(nowayout, |
39 | "Watchdog cannot be stopped once started (default=" |
40 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
41 | |
42 | static 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 | |
53 | static 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 | |
67 | static void indydog_ping(void) |
68 | { |
69 | sgimc->watchdogt = 0; |
70 | } |
71 | |
72 | /* |
73 | * Allow only one person to hold it open |
74 | */ |
75 | static 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 | |
92 | static 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 | |
102 | static 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 | |
111 | static 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 | |
154 | static 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 | |
163 | static 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 | |
172 | static struct miscdevice indydog_miscdev = { |
173 | .minor = WATCHDOG_MINOR, |
174 | .name = "watchdog", |
175 | .fops = &indydog_fops, |
176 | }; |
177 | |
178 | static struct notifier_block indydog_notifier = { |
179 | .notifier_call = indydog_notify_sys, |
180 | }; |
181 | |
182 | static 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 | |
205 | static void __exit watchdog_exit(void) |
206 | { |
207 | misc_deregister(&indydog_miscdev); |
208 | unregister_reboot_notifier(&indydog_notifier); |
209 | } |
210 | |
211 | module_init(watchdog_init); |
212 | module_exit(watchdog_exit); |
213 | |
214 | MODULE_AUTHOR("Guido Guenther <agx@sigxcpu.org>"); |
215 | MODULE_DESCRIPTION("Hardware Watchdog Device for SGI IP22"); |
216 | MODULE_LICENSE("GPL"); |
217 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
218 |
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