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13#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14
15#include <linux/bitops.h>
16#include <linux/errno.h>
17#include <linux/fs.h>
18#include <linux/init.h>
19#include <linux/kernel.h>
20#include <linux/miscdevice.h>
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/reboot.h>
24#include <linux/types.h>
25#include <linux/uaccess.h>
26#include <linux/watchdog.h>
27#include <linux/timer.h>
28#include <linux/jiffies.h>
29#include <linux/ssb/ssb_embedded.h>
30#include <asm/mach-bcm47xx/bcm47xx.h>
31
32#define DRV_NAME "bcm47xx_wdt"
33
34#define WDT_DEFAULT_TIME 30
35#define WDT_MAX_TIME 255
36
37static int wdt_time = WDT_DEFAULT_TIME;
38static bool nowayout = WATCHDOG_NOWAYOUT;
39
40module_param(wdt_time, int, 0);
41MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
42 __MODULE_STRING(WDT_DEFAULT_TIME) ")");
43
44#ifdef CONFIG_WATCHDOG_NOWAYOUT
45module_param(nowayout, bool, 0);
46MODULE_PARM_DESC(nowayout,
47 "Watchdog cannot be stopped once started (default="
48 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
49#endif
50
51static unsigned long bcm47xx_wdt_busy;
52static char expect_release;
53static struct timer_list wdt_timer;
54static atomic_t ticks;
55
56static inline void bcm47xx_wdt_hw_start(void)
57{
58
59 switch (bcm47xx_bus_type) {
60#ifdef CONFIG_BCM47XX_SSB
61 case BCM47XX_BUS_TYPE_SSB:
62 ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0xfffffff);
63 break;
64#endif
65#ifdef CONFIG_BCM47XX_BCMA
66 case BCM47XX_BUS_TYPE_BCMA:
67 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc,
68 0xfffffff);
69 break;
70#endif
71 }
72}
73
74static inline int bcm47xx_wdt_hw_stop(void)
75{
76 switch (bcm47xx_bus_type) {
77#ifdef CONFIG_BCM47XX_SSB
78 case BCM47XX_BUS_TYPE_SSB:
79 return ssb_watchdog_timer_set(&bcm47xx_bus.ssb, 0);
80#endif
81#ifdef CONFIG_BCM47XX_BCMA
82 case BCM47XX_BUS_TYPE_BCMA:
83 bcma_chipco_watchdog_timer_set(&bcm47xx_bus.bcma.bus.drv_cc, 0);
84 return 0;
85#endif
86 }
87 return -EINVAL;
88}
89
90static void bcm47xx_timer_tick(unsigned long unused)
91{
92 if (!atomic_dec_and_test(&ticks)) {
93 bcm47xx_wdt_hw_start();
94 mod_timer(&wdt_timer, jiffies + HZ);
95 } else {
96 pr_crit("Watchdog will fire soon!!!\n");
97 }
98}
99
100static inline void bcm47xx_wdt_pet(void)
101{
102 atomic_set(&ticks, wdt_time);
103}
104
105static void bcm47xx_wdt_start(void)
106{
107 bcm47xx_wdt_pet();
108 bcm47xx_timer_tick(0);
109}
110
111static void bcm47xx_wdt_pause(void)
112{
113 del_timer_sync(&wdt_timer);
114 bcm47xx_wdt_hw_stop();
115}
116
117static void bcm47xx_wdt_stop(void)
118{
119 bcm47xx_wdt_pause();
120}
121
122static int bcm47xx_wdt_settimeout(int new_time)
123{
124 if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
125 return -EINVAL;
126
127 wdt_time = new_time;
128 return 0;
129}
130
131static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
132{
133 if (test_and_set_bit(0, &bcm47xx_wdt_busy))
134 return -EBUSY;
135
136 bcm47xx_wdt_start();
137 return nonseekable_open(inode, file);
138}
139
140static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
141{
142 if (expect_release == 42) {
143 bcm47xx_wdt_stop();
144 } else {
145 pr_crit("Unexpected close, not stopping watchdog!\n");
146 bcm47xx_wdt_start();
147 }
148
149 clear_bit(0, &bcm47xx_wdt_busy);
150 expect_release = 0;
151 return 0;
152}
153
154static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
155 size_t len, loff_t *ppos)
156{
157 if (len) {
158 if (!nowayout) {
159 size_t i;
160
161 expect_release = 0;
162
163 for (i = 0; i != len; i++) {
164 char c;
165 if (get_user(c, data + i))
166 return -EFAULT;
167 if (c == 'V')
168 expect_release = 42;
169 }
170 }
171 bcm47xx_wdt_pet();
172 }
173 return len;
174}
175
176static const struct watchdog_info bcm47xx_wdt_info = {
177 .identity = DRV_NAME,
178 .options = WDIOF_SETTIMEOUT |
179 WDIOF_KEEPALIVEPING |
180 WDIOF_MAGICCLOSE,
181};
182
183static long bcm47xx_wdt_ioctl(struct file *file,
184 unsigned int cmd, unsigned long arg)
185{
186 void __user *argp = (void __user *)arg;
187 int __user *p = argp;
188 int new_value, retval = -EINVAL;
189
190 switch (cmd) {
191 case WDIOC_GETSUPPORT:
192 return copy_to_user(argp, &bcm47xx_wdt_info,
193 sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
194
195 case WDIOC_GETSTATUS:
196 case WDIOC_GETBOOTSTATUS:
197 return put_user(0, p);
198
199 case WDIOC_SETOPTIONS:
200 if (get_user(new_value, p))
201 return -EFAULT;
202
203 if (new_value & WDIOS_DISABLECARD) {
204 bcm47xx_wdt_stop();
205 retval = 0;
206 }
207
208 if (new_value & WDIOS_ENABLECARD) {
209 bcm47xx_wdt_start();
210 retval = 0;
211 }
212
213 return retval;
214
215 case WDIOC_KEEPALIVE:
216 bcm47xx_wdt_pet();
217 return 0;
218
219 case WDIOC_SETTIMEOUT:
220 if (get_user(new_value, p))
221 return -EFAULT;
222
223 if (bcm47xx_wdt_settimeout(new_value))
224 return -EINVAL;
225
226 bcm47xx_wdt_pet();
227
228 case WDIOC_GETTIMEOUT:
229 return put_user(wdt_time, p);
230
231 default:
232 return -ENOTTY;
233 }
234}
235
236static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
237 unsigned long code, void *unused)
238{
239 if (code == SYS_DOWN || code == SYS_HALT)
240 bcm47xx_wdt_stop();
241 return NOTIFY_DONE;
242}
243
244static const struct file_operations bcm47xx_wdt_fops = {
245 .owner = THIS_MODULE,
246 .llseek = no_llseek,
247 .unlocked_ioctl = bcm47xx_wdt_ioctl,
248 .open = bcm47xx_wdt_open,
249 .release = bcm47xx_wdt_release,
250 .write = bcm47xx_wdt_write,
251};
252
253static struct miscdevice bcm47xx_wdt_miscdev = {
254 .minor = WATCHDOG_MINOR,
255 .name = "watchdog",
256 .fops = &bcm47xx_wdt_fops,
257};
258
259static struct notifier_block bcm47xx_wdt_notifier = {
260 .notifier_call = bcm47xx_wdt_notify_sys,
261};
262
263static int __init bcm47xx_wdt_init(void)
264{
265 int ret;
266
267 if (bcm47xx_wdt_hw_stop() < 0)
268 return -ENODEV;
269
270 setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
271
272 if (bcm47xx_wdt_settimeout(wdt_time)) {
273 bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
274 pr_info("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 pr_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);
310
