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15#include <linux/platform_device.h>
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/timer.h>
20#include <linux/miscdevice.h>
21#include <linux/watchdog.h>
22#include <linux/fs.h>
23#include <linux/notifier.h>
24#include <linux/reboot.h>
25#include <linux/init.h>
26#include <linux/interrupt.h>
27#include <linux/uaccess.h>
28#include <asm/blackfin.h>
29
30#define stamp(fmt, args...) \
31 pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
32#define stampit() stamp("here i am")
33#define pr_devinit(fmt, args...) \
34 ({ static const __devinitconst char __fmt[] = fmt; \
35 printk(__fmt, ## args); })
36#define pr_init(fmt, args...) \
37 ({ static const __initconst char __fmt[] = fmt; \
38 printk(__fmt, ## args); })
39
40#define WATCHDOG_NAME "bfin-wdt"
41#define PFX WATCHDOG_NAME ": "
42
43
44
45
46#ifdef BF561_FAMILY
47# define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL()
48# define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT()
49# define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT()
50# define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x)
51# define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x)
52# define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x)
53#endif
54
55
56#define SWRST_RESET_WDOG 0x4000
57
58
59#define WDOG_EXPIRED 0x8000
60
61
62#define ICTL_RESET 0x0
63#define ICTL_NMI 0x2
64#define ICTL_GPI 0x4
65#define ICTL_NONE 0x6
66#define ICTL_MASK 0x6
67
68
69#define WDEN_MASK 0x0FF0
70#define WDEN_ENABLE 0x0000
71#define WDEN_DISABLE 0x0AD0
72
73
74#define WATCHDOG_TIMEOUT 20
75
76static unsigned int timeout = WATCHDOG_TIMEOUT;
77static int nowayout = WATCHDOG_NOWAYOUT;
78static struct watchdog_info bfin_wdt_info;
79static unsigned long open_check;
80static char expect_close;
81static DEFINE_SPINLOCK(bfin_wdt_spinlock);
82
83
84
85
86
87
88static int bfin_wdt_keepalive(void)
89{
90 stampit();
91 bfin_write_WDOG_STAT(0);
92 return 0;
93}
94
95
96
97
98
99
100static int bfin_wdt_stop(void)
101{
102 stampit();
103 bfin_write_WDOG_CTL(WDEN_DISABLE);
104 return 0;
105}
106
107
108
109
110
111
112
113static int bfin_wdt_start(void)
114{
115 stampit();
116 bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET);
117 return 0;
118}
119
120
121
122
123
124
125static int bfin_wdt_running(void)
126{
127 stampit();
128 return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE);
129}
130
131
132
133
134
135
136
137
138static int bfin_wdt_set_timeout(unsigned long t)
139{
140 u32 cnt;
141 unsigned long flags;
142
143 stampit();
144
145 cnt = t * get_sclk();
146 if (cnt < get_sclk()) {
147 printk(KERN_WARNING PFX "timeout value is too large\n");
148 return -EINVAL;
149 }
150
151 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
152 {
153 int run = bfin_wdt_running();
154 bfin_wdt_stop();
155 bfin_write_WDOG_CNT(cnt);
156 if (run)
157 bfin_wdt_start();
158 }
159 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
160
161 timeout = t;
162
163 return 0;
164}
165
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170
171
172
173static int bfin_wdt_open(struct inode *inode, struct file *file)
174{
175 stampit();
176
177 if (test_and_set_bit(0, &open_check))
178 return -EBUSY;
179
180 if (nowayout)
181 __module_get(THIS_MODULE);
182
183 bfin_wdt_keepalive();
184 bfin_wdt_start();
185
186 return nonseekable_open(inode, file);
187}
188
189
190
191
192
193
194
195
196static int bfin_wdt_release(struct inode *inode, struct file *file)
197{
198 stampit();
199
200 if (expect_close == 42)
201 bfin_wdt_stop();
202 else {
203 printk(KERN_CRIT PFX
204 "Unexpected close, not stopping watchdog!\n");
205 bfin_wdt_keepalive();
206 }
207 expect_close = 0;
208 clear_bit(0, &open_check);
209 return 0;
210}
211
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215
216
217
218
219
220
221static ssize_t bfin_wdt_write(struct file *file, const char __user *data,
222 size_t len, loff_t *ppos)
223{
224 stampit();
225
226 if (len) {
227 if (!nowayout) {
228 size_t i;
229
230
231 expect_close = 0;
232
233 for (i = 0; i != len; i++) {
234 char c;
235 if (get_user(c, data + i))
236 return -EFAULT;
237 if (c == 'V')
238 expect_close = 42;
239 }
240 }
241 bfin_wdt_keepalive();
242 }
243
244 return len;
245}
246
247
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250
251
252
253
254
255
256static long bfin_wdt_ioctl(struct file *file,
257 unsigned int cmd, unsigned long arg)
258{
259 void __user *argp = (void __user *)arg;
260 int __user *p = argp;
261
262 stampit();
263
264 switch (cmd) {
265 case WDIOC_GETSUPPORT:
266 if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info)))
267 return -EFAULT;
268 else
269 return 0;
270 case WDIOC_GETSTATUS:
271 case WDIOC_GETBOOTSTATUS:
272 return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p);
273 case WDIOC_SETOPTIONS: {
274 unsigned long flags;
275 int options, ret = -EINVAL;
276
277 if (get_user(options, p))
278 return -EFAULT;
279
280 spin_lock_irqsave(&bfin_wdt_spinlock, flags);
281 if (options & WDIOS_DISABLECARD) {
282 bfin_wdt_stop();
283 ret = 0;
284 }
285 if (options & WDIOS_ENABLECARD) {
286 bfin_wdt_start();
287 ret = 0;
288 }
289 spin_unlock_irqrestore(&bfin_wdt_spinlock, flags);
290 return ret;
291 }
292 case WDIOC_KEEPALIVE:
293 bfin_wdt_keepalive();
294 return 0;
295 case WDIOC_SETTIMEOUT: {
296 int new_timeout;
297
298 if (get_user(new_timeout, p))
299 return -EFAULT;
300 if (bfin_wdt_set_timeout(new_timeout))
301 return -EINVAL;
302 }
303
304 case WDIOC_GETTIMEOUT:
305 return put_user(timeout, p);
306 default:
307 return -ENOTTY;
308 }
309}
310
311
312
313
314
315
316
317
318
319
320static int bfin_wdt_notify_sys(struct notifier_block *this,
321 unsigned long code, void *unused)
322{
323 stampit();
324
325 if (code == SYS_DOWN || code == SYS_HALT)
326 bfin_wdt_stop();
327
328 return NOTIFY_DONE;
329}
330
331#ifdef CONFIG_PM
332static int state_before_suspend;
333
334
335
336
337
338
339
340
341
342
343static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state)
344{
345 stampit();
346
347 state_before_suspend = bfin_wdt_running();
348 bfin_wdt_stop();
349
350 return 0;
351}
352
353
354
355
356
357
358
359static int bfin_wdt_resume(struct platform_device *pdev)
360{
361 stampit();
362
363 if (state_before_suspend) {
364 bfin_wdt_set_timeout(timeout);
365 bfin_wdt_start();
366 }
367
368 return 0;
369}
370#else
371# define bfin_wdt_suspend NULL
372# define bfin_wdt_resume NULL
373#endif
374
375static const struct file_operations bfin_wdt_fops = {
376 .owner = THIS_MODULE,
377 .llseek = no_llseek,
378 .write = bfin_wdt_write,
379 .unlocked_ioctl = bfin_wdt_ioctl,
380 .open = bfin_wdt_open,
381 .release = bfin_wdt_release,
382};
383
384static struct miscdevice bfin_wdt_miscdev = {
385 .minor = WATCHDOG_MINOR,
386 .name = "watchdog",
387 .fops = &bfin_wdt_fops,
388};
389
390static struct watchdog_info bfin_wdt_info = {
391 .identity = "Blackfin Watchdog",
392 .options = WDIOF_SETTIMEOUT |
393 WDIOF_KEEPALIVEPING |
394 WDIOF_MAGICCLOSE,
395};
396
397static struct notifier_block bfin_wdt_notifier = {
398 .notifier_call = bfin_wdt_notify_sys,
399};
400
401
402
403
404
405
406
407static int __devinit bfin_wdt_probe(struct platform_device *pdev)
408{
409 int ret;
410
411 ret = register_reboot_notifier(&bfin_wdt_notifier);
412 if (ret) {
413 pr_devinit(KERN_ERR PFX
414 "cannot register reboot notifier (err=%d)\n", ret);
415 return ret;
416 }
417
418 ret = misc_register(&bfin_wdt_miscdev);
419 if (ret) {
420 pr_devinit(KERN_ERR PFX
421 "cannot register miscdev on minor=%d (err=%d)\n",
422 WATCHDOG_MINOR, ret);
423 unregister_reboot_notifier(&bfin_wdt_notifier);
424 return ret;
425 }
426
427 pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n",
428 timeout, nowayout);
429
430 return 0;
431}
432
433
434
435
436
437
438
439static int __devexit bfin_wdt_remove(struct platform_device *pdev)
440{
441 misc_deregister(&bfin_wdt_miscdev);
442 unregister_reboot_notifier(&bfin_wdt_notifier);
443 return 0;
444}
445
446static struct platform_device *bfin_wdt_device;
447
448static struct platform_driver bfin_wdt_driver = {
449 .probe = bfin_wdt_probe,
450 .remove = __devexit_p(bfin_wdt_remove),
451 .suspend = bfin_wdt_suspend,
452 .resume = bfin_wdt_resume,
453 .driver = {
454 .name = WATCHDOG_NAME,
455 .owner = THIS_MODULE,
456 },
457};
458
459
460
461
462
463
464
465static int __init bfin_wdt_init(void)
466{
467 int ret;
468
469 stampit();
470
471
472 if (bfin_wdt_set_timeout(timeout))
473 return -EINVAL;
474
475
476
477
478 ret = platform_driver_register(&bfin_wdt_driver);
479 if (ret) {
480 pr_init(KERN_ERR PFX "unable to register driver\n");
481 return ret;
482 }
483
484 bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME,
485 -1, NULL, 0);
486 if (IS_ERR(bfin_wdt_device)) {
487 pr_init(KERN_ERR PFX "unable to register device\n");
488 platform_driver_unregister(&bfin_wdt_driver);
489 return PTR_ERR(bfin_wdt_device);
490 }
491
492 return 0;
493}
494
495
496
497
498
499
500
501static void __exit bfin_wdt_exit(void)
502{
503 platform_device_unregister(bfin_wdt_device);
504 platform_driver_unregister(&bfin_wdt_driver);
505}
506
507module_init(bfin_wdt_init);
508module_exit(bfin_wdt_exit);
509
510MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>");
511MODULE_DESCRIPTION("Blackfin Watchdog Device Driver");
512MODULE_LICENSE("GPL");
513MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
514
515module_param(timeout, uint, 0);
516MODULE_PARM_DESC(timeout,
517 "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default="
518 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
519
520module_param(nowayout, int, 0);
521MODULE_PARM_DESC(nowayout,
522 "Watchdog cannot be stopped once started (default="
523 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
524