90074dce |
1 | /* |
2 | * Watchdog driver for Broadcom BCM47XX |
3 | * |
4 | * Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs> |
5 | * Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr> |
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 | |
13 | #include <linux/bitops.h> |
14 | #include <linux/errno.h> |
15 | #include <linux/fs.h> |
16 | #include <linux/init.h> |
17 | #include <linux/kernel.h> |
18 | #include <linux/miscdevice.h> |
19 | #include <linux/module.h> |
20 | #include <linux/moduleparam.h> |
21 | #include <linux/reboot.h> |
22 | #include <linux/types.h> |
23 | #include <linux/uaccess.h> |
24 | #include <linux/watchdog.h> |
25 | #include <linux/timer.h> |
26 | #include <linux/jiffies.h> |
27 | #include <linux/ssb/ssb_embedded.h> |
28 | #include <asm/mach-bcm47xx/bcm47xx.h> |
29 | |
30 | #define DRV_NAME "bcm47xx_wdt" |
31 | |
32 | #define WDT_DEFAULT_TIME 30 /* seconds */ |
33 | #define WDT_MAX_TIME 255 /* seconds */ |
34 | |
35 | static int wdt_time = WDT_DEFAULT_TIME; |
36 | static int nowayout = WATCHDOG_NOWAYOUT; |
37 | |
38 | module_param(wdt_time, int, 0); |
39 | MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default=" |
40 | __MODULE_STRING(WDT_DEFAULT_TIME) ")"); |
41 | |
42 | #ifdef CONFIG_WATCHDOG_NOWAYOUT |
43 | module_param(nowayout, int, 0); |
44 | MODULE_PARM_DESC(nowayout, |
45 | "Watchdog cannot be stopped once started (default=" |
46 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
47 | #endif |
48 | |
49 | static unsigned long bcm47xx_wdt_busy; |
50 | static char expect_release; |
51 | static struct timer_list wdt_timer; |
52 | static atomic_t ticks; |
53 | |
54 | static inline void bcm47xx_wdt_hw_start(void) |
55 | { |
56 | /* this is 2,5s on 100Mhz clock and 2s on 133 Mhz */ |
57 | ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff); |
58 | } |
59 | |
60 | static inline int bcm47xx_wdt_hw_stop(void) |
61 | { |
62 | return ssb_watchdog_timer_set(&ssb_bcm47xx, 0); |
63 | } |
64 | |
65 | static void bcm47xx_timer_tick(unsigned long unused) |
66 | { |
67 | if (!atomic_dec_and_test(&ticks)) { |
68 | bcm47xx_wdt_hw_start(); |
69 | mod_timer(&wdt_timer, jiffies + HZ); |
70 | } else { |
71 | printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n"); |
72 | } |
73 | } |
74 | |
75 | static inline void bcm47xx_wdt_pet(void) |
76 | { |
77 | atomic_set(&ticks, wdt_time); |
78 | } |
79 | |
80 | static void bcm47xx_wdt_start(void) |
81 | { |
82 | bcm47xx_wdt_pet(); |
83 | bcm47xx_timer_tick(0); |
84 | } |
85 | |
86 | static void bcm47xx_wdt_pause(void) |
87 | { |
88 | del_timer_sync(&wdt_timer); |
89 | bcm47xx_wdt_hw_stop(); |
90 | } |
91 | |
92 | static void bcm47xx_wdt_stop(void) |
93 | { |
94 | bcm47xx_wdt_pause(); |
95 | } |
96 | |
97 | static int bcm47xx_wdt_settimeout(int new_time) |
98 | { |
99 | if ((new_time <= 0) || (new_time > WDT_MAX_TIME)) |
100 | return -EINVAL; |
101 | |
102 | wdt_time = new_time; |
103 | return 0; |
104 | } |
105 | |
106 | static int bcm47xx_wdt_open(struct inode *inode, struct file *file) |
107 | { |
108 | if (test_and_set_bit(0, &bcm47xx_wdt_busy)) |
109 | return -EBUSY; |
110 | |
111 | bcm47xx_wdt_start(); |
112 | return nonseekable_open(inode, file); |
113 | } |
114 | |
115 | static int bcm47xx_wdt_release(struct inode *inode, struct file *file) |
116 | { |
117 | if (expect_release == 42) { |
118 | bcm47xx_wdt_stop(); |
119 | } else { |
120 | printk(KERN_CRIT DRV_NAME |
121 | ": Unexpected close, not stopping watchdog!\n"); |
122 | bcm47xx_wdt_start(); |
123 | } |
124 | |
125 | clear_bit(0, &bcm47xx_wdt_busy); |
126 | expect_release = 0; |
127 | return 0; |
128 | } |
129 | |
130 | static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data, |
131 | size_t len, loff_t *ppos) |
132 | { |
133 | if (len) { |
134 | if (!nowayout) { |
135 | size_t i; |
136 | |
137 | expect_release = 0; |
138 | |
139 | for (i = 0; i != len; i++) { |
140 | char c; |
141 | if (get_user(c, data + i)) |
142 | return -EFAULT; |
143 | if (c == 'V') |
144 | expect_release = 42; |
145 | } |
146 | } |
147 | bcm47xx_wdt_pet(); |
148 | } |
149 | return len; |
150 | } |
151 | |
42747d71 |
152 | static const struct watchdog_info bcm47xx_wdt_info = { |
90074dce |
153 | .identity = DRV_NAME, |
154 | .options = WDIOF_SETTIMEOUT | |
155 | WDIOF_KEEPALIVEPING | |
156 | WDIOF_MAGICCLOSE, |
157 | }; |
158 | |
159 | static long bcm47xx_wdt_ioctl(struct file *file, |
160 | unsigned int cmd, unsigned long arg) |
161 | { |
162 | void __user *argp = (void __user *)arg; |
163 | int __user *p = argp; |
b86a6c6c |
164 | int new_value, retval = -EINVAL; |
90074dce |
165 | |
166 | switch (cmd) { |
167 | case WDIOC_GETSUPPORT: |
168 | return copy_to_user(argp, &bcm47xx_wdt_info, |
169 | sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0; |
170 | |
171 | case WDIOC_GETSTATUS: |
172 | case WDIOC_GETBOOTSTATUS: |
173 | return put_user(0, p); |
174 | |
175 | case WDIOC_SETOPTIONS: |
176 | if (get_user(new_value, p)) |
177 | return -EFAULT; |
178 | |
179 | if (new_value & WDIOS_DISABLECARD) { |
180 | bcm47xx_wdt_stop(); |
181 | retval = 0; |
182 | } |
183 | |
184 | if (new_value & WDIOS_ENABLECARD) { |
185 | bcm47xx_wdt_start(); |
186 | retval = 0; |
187 | } |
188 | |
189 | return retval; |
190 | |
191 | case WDIOC_KEEPALIVE: |
192 | bcm47xx_wdt_pet(); |
193 | return 0; |
194 | |
195 | case WDIOC_SETTIMEOUT: |
196 | if (get_user(new_value, p)) |
197 | return -EFAULT; |
198 | |
199 | if (bcm47xx_wdt_settimeout(new_value)) |
200 | return -EINVAL; |
201 | |
202 | bcm47xx_wdt_pet(); |
203 | |
204 | case WDIOC_GETTIMEOUT: |
205 | return put_user(wdt_time, p); |
206 | |
207 | default: |
208 | return -ENOTTY; |
209 | } |
210 | } |
211 | |
212 | static int bcm47xx_wdt_notify_sys(struct notifier_block *this, |
213 | unsigned long code, void *unused) |
214 | { |
215 | if (code == SYS_DOWN || code == SYS_HALT) |
216 | bcm47xx_wdt_stop(); |
217 | return NOTIFY_DONE; |
218 | } |
219 | |
220 | static const struct file_operations bcm47xx_wdt_fops = { |
221 | .owner = THIS_MODULE, |
222 | .llseek = no_llseek, |
223 | .unlocked_ioctl = bcm47xx_wdt_ioctl, |
224 | .open = bcm47xx_wdt_open, |
225 | .release = bcm47xx_wdt_release, |
226 | .write = bcm47xx_wdt_write, |
227 | }; |
228 | |
229 | static struct miscdevice bcm47xx_wdt_miscdev = { |
230 | .minor = WATCHDOG_MINOR, |
231 | .name = "watchdog", |
232 | .fops = &bcm47xx_wdt_fops, |
233 | }; |
234 | |
235 | static struct notifier_block bcm47xx_wdt_notifier = { |
236 | .notifier_call = bcm47xx_wdt_notify_sys, |
237 | }; |
238 | |
239 | static int __init bcm47xx_wdt_init(void) |
240 | { |
241 | int ret; |
242 | |
243 | if (bcm47xx_wdt_hw_stop() < 0) |
244 | return -ENODEV; |
245 | |
246 | setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L); |
247 | |
248 | if (bcm47xx_wdt_settimeout(wdt_time)) { |
249 | bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME); |
250 | printk(KERN_INFO DRV_NAME ": " |
251 | "wdt_time value must be 0 < wdt_time < %d, using %d\n", |
252 | (WDT_MAX_TIME + 1), wdt_time); |
253 | } |
254 | |
255 | ret = register_reboot_notifier(&bcm47xx_wdt_notifier); |
256 | if (ret) |
257 | return ret; |
258 | |
259 | ret = misc_register(&bcm47xx_wdt_miscdev); |
260 | if (ret) { |
261 | unregister_reboot_notifier(&bcm47xx_wdt_notifier); |
262 | return ret; |
263 | } |
264 | |
265 | printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n", |
266 | wdt_time, nowayout ? ", nowayout" : ""); |
267 | return 0; |
268 | } |
269 | |
270 | static void __exit bcm47xx_wdt_exit(void) |
271 | { |
272 | if (!nowayout) |
273 | bcm47xx_wdt_stop(); |
274 | |
275 | misc_deregister(&bcm47xx_wdt_miscdev); |
276 | |
277 | unregister_reboot_notifier(&bcm47xx_wdt_notifier); |
278 | } |
279 | |
280 | module_init(bcm47xx_wdt_init); |
281 | module_exit(bcm47xx_wdt_exit); |
282 | |
283 | MODULE_AUTHOR("Aleksandar Radovanovic"); |
284 | MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx"); |
285 | MODULE_LICENSE("GPL"); |
286 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |