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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
35static int wdt_time = WDT_DEFAULT_TIME;
36static int nowayout = WATCHDOG_NOWAYOUT;
37
38module_param(wdt_time, int, 0);
39MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
40 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
41
42#ifdef CONFIG_WATCHDOG_NOWAYOUT
43module_param(nowayout, int, 0);
44MODULE_PARM_DESC(nowayout,
45 "Watchdog cannot be stopped once started (default="
46 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
47#endif
48
49static unsigned long bcm47xx_wdt_busy;
50static char expect_release;
51static struct timer_list wdt_timer;
52static atomic_t ticks;
53
54static inline void bcm47xx_wdt_hw_start(void)
55{
56 /* this is 2,5s on 100Mhz clock and 2s on 133 Mhz */
08ccf572 57 switch (bcm47xx_bus_type) {
a656ffcb 58#ifdef CONFIG_BCM47XX_SSB
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59 case BCM47XX_BUS_TYPE_SSB:
60 ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0xfffffff);
61 break;
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62#endif
63#ifdef CONFIG_BCM47XX_BCMA
64 case BCM47XX_BUS_TYPE_BCMA:
65 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc,
66 0xfffffff);
67 break;
a656ffcb 68#endif
08ccf572 69 }
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70}
71
72static inline int bcm47xx_wdt_hw_stop(void)
73{
08ccf572 74 switch (bcm47xx_bus_type) {
a656ffcb 75#ifdef CONFIG_BCM47XX_SSB
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76 case BCM47XX_BUS_TYPE_SSB:
77 return ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0);
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78#endif
79#ifdef CONFIG_BCM47XX_BCMA
80 case BCM47XX_BUS_TYPE_BCMA:
81 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc, 0);
82 return 0;
a656ffcb 83#endif
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84 }
85 return -EINVAL;
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86}
87
88static void bcm47xx_timer_tick(unsigned long unused)
89{
90 if (!atomic_dec_and_test(&ticks)) {
91 bcm47xx_wdt_hw_start();
92 mod_timer(&wdt_timer, jiffies + HZ);
93 } else {
94 printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
95 }
96}
97
98static inline void bcm47xx_wdt_pet(void)
99{
100 atomic_set(&ticks, wdt_time);
101}
102
103static void bcm47xx_wdt_start(void)
104{
105 bcm47xx_wdt_pet();
106 bcm47xx_timer_tick(0);
107}
108
109static void bcm47xx_wdt_pause(void)
110{
111 del_timer_sync(&wdt_timer);
112 bcm47xx_wdt_hw_stop();
113}
114
115static void bcm47xx_wdt_stop(void)
116{
117 bcm47xx_wdt_pause();
118}
119
120static int bcm47xx_wdt_settimeout(int new_time)
121{
122 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
123 return -EINVAL;
124
125 wdt_time = new_time;
126 return 0;
127}
128
129static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
130{
131 if (test_and_set_bit(0, &bcm47xx_wdt_busy))
132 return -EBUSY;
133
134 bcm47xx_wdt_start();
135 return nonseekable_open(inode, file);
136}
137
138static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
139{
140 if (expect_release == 42) {
141 bcm47xx_wdt_stop();
142 } else {
143 printk(KERN_CRIT DRV_NAME
144 ": Unexpected close, not stopping watchdog!\n");
145 bcm47xx_wdt_start();
146 }
147
148 clear_bit(0, &bcm47xx_wdt_busy);
149 expect_release = 0;
150 return 0;
151}
152
153static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
154 size_t len, loff_t *ppos)
155{
156 if (len) {
157 if (!nowayout) {
158 size_t i;
159
160 expect_release = 0;
161
162 for (i = 0; i != len; i++) {
163 char c;
164 if (get_user(c, data + i))
165 return -EFAULT;
166 if (c == 'V')
167 expect_release = 42;
168 }
169 }
170 bcm47xx_wdt_pet();
171 }
172 return len;
173}
174
42747d71 175static const struct watchdog_info bcm47xx_wdt_info = {
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176 .identity = DRV_NAME,
177 .options = WDIOF_SETTIMEOUT |
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178 WDIOF_KEEPALIVEPING |
179 WDIOF_MAGICCLOSE,
180};
181
182static long bcm47xx_wdt_ioctl(struct file *file,
183 unsigned int cmd, unsigned long arg)
184{
185 void __user *argp = (void __user *)arg;
186 int __user *p = argp;
b86a6c6c 187 int new_value, retval = -EINVAL;
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188
189 switch (cmd) {
190 case WDIOC_GETSUPPORT:
191 return copy_to_user(argp, &bcm47xx_wdt_info,
192 sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
193
194 case WDIOC_GETSTATUS:
195 case WDIOC_GETBOOTSTATUS:
196 return put_user(0, p);
197
198 case WDIOC_SETOPTIONS:
199 if (get_user(new_value, p))
200 return -EFAULT;
201
202 if (new_value & WDIOS_DISABLECARD) {
203 bcm47xx_wdt_stop();
204 retval = 0;
205 }
206
207 if (new_value & WDIOS_ENABLECARD) {
208 bcm47xx_wdt_start();
209 retval = 0;
210 }
211
212 return retval;
213
214 case WDIOC_KEEPALIVE:
215 bcm47xx_wdt_pet();
216 return 0;
217
218 case WDIOC_SETTIMEOUT:
219 if (get_user(new_value, p))
220 return -EFAULT;
221
222 if (bcm47xx_wdt_settimeout(new_value))
223 return -EINVAL;
224
225 bcm47xx_wdt_pet();
226
227 case WDIOC_GETTIMEOUT:
228 return put_user(wdt_time, p);
229
230 default:
231 return -ENOTTY;
232 }
233}
234
235static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
236 unsigned long code, void *unused)
237{
238 if (code == SYS_DOWN || code == SYS_HALT)
239 bcm47xx_wdt_stop();
240 return NOTIFY_DONE;
241}
242
243static const struct file_operations bcm47xx_wdt_fops = {
244 .owner = THIS_MODULE,
245 .llseek = no_llseek,
246 .unlocked_ioctl = bcm47xx_wdt_ioctl,
247 .open = bcm47xx_wdt_open,
248 .release = bcm47xx_wdt_release,
249 .write = bcm47xx_wdt_write,
250};
251
252static struct miscdevice bcm47xx_wdt_miscdev = {
253 .minor = WATCHDOG_MINOR,
254 .name = "watchdog",
255 .fops = &bcm47xx_wdt_fops,
256};
257
258static struct notifier_block bcm47xx_wdt_notifier = {
259 .notifier_call = bcm47xx_wdt_notify_sys,
260};
261
262static int __init bcm47xx_wdt_init(void)
263{
264 int ret;
265
266 if (bcm47xx_wdt_hw_stop() < 0)
267 return -ENODEV;
268
269 setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
270
271 if (bcm47xx_wdt_settimeout(wdt_time)) {
272 bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
273 printk(KERN_INFO DRV_NAME ": "
274 "wdt_time value must be 0 < wdt_time < %d, using %d\n",
275 (WDT_MAX_TIME + 1), wdt_time);
276 }
277
278 ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
279 if (ret)
280 return ret;
281
282 ret = misc_register(&bcm47xx_wdt_miscdev);
283 if (ret) {
284 unregister_reboot_notifier(&bcm47xx_wdt_notifier);
285 return ret;
286 }
287
288 printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
289 wdt_time, nowayout ? ", nowayout" : "");
290 return 0;
291}
292
293static void __exit bcm47xx_wdt_exit(void)
294{
295 if (!nowayout)
296 bcm47xx_wdt_stop();
297
298 misc_deregister(&bcm47xx_wdt_miscdev);
299
300 unregister_reboot_notifier(&bcm47xx_wdt_notifier);
301}
302
303module_init(bcm47xx_wdt_init);
304module_exit(bcm47xx_wdt_exit);
305
306MODULE_AUTHOR("Aleksandar Radovanovic");
307MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
308MODULE_LICENSE("GPL");
309MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);