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
152 static struct watchdog_info bcm47xx_wdt_info = {
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;
164 int new_value, retval = -EINVAL;
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);
287
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