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1e6d320f BW |
1 | /* |
2 | * Blackfin On-Chip Watchdog Driver | |
3 | * Supports BF53[123]/BF53[467]/BF54[2489]/BF561 | |
4 | * | |
5 | * Originally based on softdog.c | |
6 | * Copyright 2006-2007 Analog Devices Inc. | |
7 | * Copyright 2006-2007 Michele d'Amico | |
8 | * Copyright 1996 Alan Cox <alan@redhat.com> | |
9 | * | |
10 | * Enter bugs at http://blackfin.uclinux.org/ | |
11 | * | |
12 | * Licensed under the GPL-2 or later. | |
13 | */ | |
14 | ||
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 <asm/blackfin.h> | |
28 | #include <asm/uaccess.h> | |
29 | ||
30 | #define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) | |
31 | #define stampit() stamp("here i am") | |
bb59b557 | 32 | #define pr_init(fmt, args...) ({ static const __initdata char __fmt[] = fmt; printk(__fmt, ## args); }) |
1e6d320f BW |
33 | |
34 | #define WATCHDOG_NAME "bfin-wdt" | |
35 | #define PFX WATCHDOG_NAME ": " | |
36 | ||
37 | /* The BF561 has two watchdogs (one per core), but since Linux | |
38 | * only runs on core A, we'll just work with that one. | |
39 | */ | |
40 | #ifdef BF561_FAMILY | |
41 | # define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL() | |
42 | # define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT() | |
43 | # define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT() | |
44 | # define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x) | |
45 | # define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x) | |
46 | # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x) | |
47 | #endif | |
48 | ||
49 | /* Bit in SWRST that indicates boot caused by watchdog */ | |
50 | #define SWRST_RESET_WDOG 0x4000 | |
51 | ||
52 | /* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */ | |
53 | #define WDOG_EXPIRED 0x8000 | |
54 | ||
55 | /* Masks for WDEV field in WDOG_CTL register */ | |
56 | #define ICTL_RESET 0x0 | |
57 | #define ICTL_NMI 0x2 | |
58 | #define ICTL_GPI 0x4 | |
59 | #define ICTL_NONE 0x6 | |
60 | #define ICTL_MASK 0x6 | |
61 | ||
62 | /* Masks for WDEN field in WDOG_CTL register */ | |
63 | #define WDEN_MASK 0x0FF0 | |
64 | #define WDEN_ENABLE 0x0000 | |
65 | #define WDEN_DISABLE 0x0AD0 | |
66 | ||
67 | /* some defaults */ | |
68 | #define WATCHDOG_TIMEOUT 20 | |
69 | ||
70 | static unsigned int timeout = WATCHDOG_TIMEOUT; | |
71 | static int nowayout = WATCHDOG_NOWAYOUT; | |
72 | static struct watchdog_info bfin_wdt_info; | |
73 | static unsigned long open_check; | |
74 | static char expect_close; | |
bf6350a3 | 75 | static DEFINE_SPINLOCK(bfin_wdt_spinlock); |
1e6d320f BW |
76 | |
77 | /** | |
78 | * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive | |
79 | * | |
80 | * The Userspace watchdog got a KeepAlive: schedule the next timeout. | |
81 | */ | |
82 | static int bfin_wdt_keepalive(void) | |
83 | { | |
84 | stampit(); | |
85 | bfin_write_WDOG_STAT(0); | |
86 | return 0; | |
87 | } | |
88 | ||
89 | /** | |
90 | * bfin_wdt_stop - Stop the Watchdog | |
91 | * | |
92 | * Stops the on-chip watchdog. | |
93 | */ | |
94 | static int bfin_wdt_stop(void) | |
95 | { | |
96 | stampit(); | |
97 | bfin_write_WDOG_CTL(WDEN_DISABLE); | |
98 | return 0; | |
99 | } | |
100 | ||
101 | /** | |
102 | * bfin_wdt_start - Start the Watchdog | |
103 | * | |
104 | * Starts the on-chip watchdog. Automatically loads WDOG_CNT | |
105 | * into WDOG_STAT for us. | |
106 | */ | |
107 | static int bfin_wdt_start(void) | |
108 | { | |
109 | stampit(); | |
110 | bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET); | |
111 | return 0; | |
112 | } | |
113 | ||
114 | /** | |
115 | * bfin_wdt_running - Check Watchdog status | |
116 | * | |
117 | * See if the watchdog is running. | |
118 | */ | |
119 | static int bfin_wdt_running(void) | |
120 | { | |
121 | stampit(); | |
122 | return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE); | |
123 | } | |
124 | ||
125 | /** | |
126 | * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout | |
127 | * @t: new timeout value (in seconds) | |
128 | * | |
129 | * Translate the specified timeout in seconds into System Clock | |
130 | * terms which is what the on-chip Watchdog requires. | |
131 | */ | |
132 | static int bfin_wdt_set_timeout(unsigned long t) | |
133 | { | |
134 | u32 cnt; | |
135 | unsigned long flags; | |
136 | ||
137 | stampit(); | |
138 | ||
139 | cnt = t * get_sclk(); | |
140 | if (cnt < get_sclk()) { | |
141 | printk(KERN_WARNING PFX "timeout value is too large\n"); | |
142 | return -EINVAL; | |
143 | } | |
144 | ||
145 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
146 | { | |
147 | int run = bfin_wdt_running(); | |
148 | bfin_wdt_stop(); | |
149 | bfin_write_WDOG_CNT(cnt); | |
150 | if (run) bfin_wdt_start(); | |
151 | } | |
152 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); | |
153 | ||
154 | timeout = t; | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | /** | |
160 | * bfin_wdt_open - Open the Device | |
161 | * @inode: inode of device | |
162 | * @file: file handle of device | |
163 | * | |
164 | * Watchdog device is opened and started. | |
165 | */ | |
166 | static int bfin_wdt_open(struct inode *inode, struct file *file) | |
167 | { | |
168 | stampit(); | |
169 | ||
170 | if (test_and_set_bit(0, &open_check)) | |
171 | return -EBUSY; | |
172 | ||
173 | if (nowayout) | |
174 | __module_get(THIS_MODULE); | |
175 | ||
176 | bfin_wdt_keepalive(); | |
177 | bfin_wdt_start(); | |
178 | ||
179 | return nonseekable_open(inode, file); | |
180 | } | |
181 | ||
182 | /** | |
183 | * bfin_wdt_close - Close the Device | |
184 | * @inode: inode of device | |
185 | * @file: file handle of device | |
186 | * | |
187 | * Watchdog device is closed and stopped. | |
188 | */ | |
189 | static int bfin_wdt_release(struct inode *inode, struct file *file) | |
190 | { | |
191 | stampit(); | |
192 | ||
193 | if (expect_close == 42) { | |
194 | bfin_wdt_stop(); | |
195 | } else { | |
196 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | |
197 | bfin_wdt_keepalive(); | |
198 | } | |
199 | ||
200 | expect_close = 0; | |
201 | clear_bit(0, &open_check); | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
206 | /** | |
207 | * bfin_wdt_write - Write to Device | |
208 | * @file: file handle of device | |
209 | * @buf: buffer to write | |
210 | * @count: length of buffer | |
211 | * @ppos: offset | |
212 | * | |
213 | * Pings the watchdog on write. | |
214 | */ | |
215 | static ssize_t bfin_wdt_write(struct file *file, const char __user *data, | |
216 | size_t len, loff_t *ppos) | |
217 | { | |
218 | stampit(); | |
219 | ||
220 | if (len) { | |
221 | if (!nowayout) { | |
222 | size_t i; | |
223 | ||
224 | /* In case it was set long ago */ | |
225 | expect_close = 0; | |
226 | ||
227 | for (i = 0; i != len; i++) { | |
228 | char c; | |
229 | if (get_user(c, data + i)) | |
230 | return -EFAULT; | |
231 | if (c == 'V') | |
232 | expect_close = 42; | |
233 | } | |
234 | } | |
235 | bfin_wdt_keepalive(); | |
236 | } | |
237 | ||
238 | return len; | |
239 | } | |
240 | ||
241 | /** | |
242 | * bfin_wdt_ioctl - Query Device | |
243 | * @inode: inode of device | |
244 | * @file: file handle of device | |
245 | * @cmd: watchdog command | |
246 | * @arg: argument | |
247 | * | |
248 | * Query basic information from the device or ping it, as outlined by the | |
249 | * watchdog API. | |
250 | */ | |
251 | static int bfin_wdt_ioctl(struct inode *inode, struct file *file, | |
252 | unsigned int cmd, unsigned long arg) | |
253 | { | |
254 | void __user *argp = (void __user *)arg; | |
255 | int __user *p = argp; | |
256 | ||
257 | stampit(); | |
258 | ||
259 | switch (cmd) { | |
260 | default: | |
261 | return -ENOTTY; | |
262 | ||
263 | case WDIOC_GETSUPPORT: | |
264 | if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info))) | |
265 | return -EFAULT; | |
266 | else | |
267 | return 0; | |
268 | ||
269 | case WDIOC_GETSTATUS: | |
270 | case WDIOC_GETBOOTSTATUS: | |
271 | return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p); | |
272 | ||
273 | case WDIOC_KEEPALIVE: | |
274 | bfin_wdt_keepalive(); | |
275 | return 0; | |
276 | ||
277 | case WDIOC_SETTIMEOUT: { | |
278 | int new_timeout; | |
279 | ||
280 | if (get_user(new_timeout, p)) | |
281 | return -EFAULT; | |
282 | ||
283 | if (bfin_wdt_set_timeout(new_timeout)) | |
284 | return -EINVAL; | |
285 | } | |
286 | /* Fall */ | |
287 | case WDIOC_GETTIMEOUT: | |
288 | return put_user(timeout, p); | |
289 | ||
290 | case WDIOC_SETOPTIONS: { | |
291 | unsigned long flags; | |
292 | int options, ret = -EINVAL; | |
293 | ||
294 | if (get_user(options, p)) | |
295 | return -EFAULT; | |
296 | ||
297 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
298 | ||
299 | if (options & WDIOS_DISABLECARD) { | |
300 | bfin_wdt_stop(); | |
301 | ret = 0; | |
302 | } | |
303 | ||
304 | if (options & WDIOS_ENABLECARD) { | |
305 | bfin_wdt_start(); | |
306 | ret = 0; | |
307 | } | |
308 | ||
309 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); | |
310 | ||
311 | return ret; | |
312 | } | |
313 | } | |
314 | } | |
315 | ||
316 | /** | |
317 | * bfin_wdt_notify_sys - Notifier Handler | |
318 | * @this: notifier block | |
319 | * @code: notifier event | |
320 | * @unused: unused | |
321 | * | |
322 | * Handles specific events, such as turning off the watchdog during a | |
323 | * shutdown event. | |
324 | */ | |
325 | static int bfin_wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
326 | void *unused) | |
327 | { | |
328 | stampit(); | |
329 | ||
330 | if (code == SYS_DOWN || code == SYS_HALT) | |
331 | bfin_wdt_stop(); | |
332 | ||
333 | return NOTIFY_DONE; | |
334 | } | |
335 | ||
336 | #ifdef CONFIG_PM | |
337 | static int state_before_suspend; | |
338 | ||
339 | /** | |
340 | * bfin_wdt_suspend - suspend the watchdog | |
341 | * @pdev: device being suspended | |
342 | * @state: requested suspend state | |
343 | * | |
344 | * Remember if the watchdog was running and stop it. | |
345 | * TODO: is this even right? Doesn't seem to be any | |
346 | * standard in the watchdog world ... | |
347 | */ | |
348 | static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state) | |
349 | { | |
350 | stampit(); | |
351 | ||
352 | state_before_suspend = bfin_wdt_running(); | |
353 | bfin_wdt_stop(); | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | /** | |
359 | * bfin_wdt_resume - resume the watchdog | |
360 | * @pdev: device being resumed | |
361 | * | |
362 | * If the watchdog was running, turn it back on. | |
363 | */ | |
364 | static int bfin_wdt_resume(struct platform_device *pdev) | |
365 | { | |
366 | stampit(); | |
367 | ||
368 | if (state_before_suspend) { | |
369 | bfin_wdt_set_timeout(timeout); | |
370 | bfin_wdt_start(); | |
371 | } | |
372 | ||
373 | return 0; | |
374 | } | |
375 | #else | |
376 | # define bfin_wdt_suspend NULL | |
377 | # define bfin_wdt_resume NULL | |
378 | #endif | |
379 | ||
380 | static struct platform_device bfin_wdt_device = { | |
381 | .name = WATCHDOG_NAME, | |
382 | .id = -1, | |
383 | }; | |
384 | ||
385 | static struct platform_driver bfin_wdt_driver = { | |
386 | .driver = { | |
387 | .name = WATCHDOG_NAME, | |
388 | .owner = THIS_MODULE, | |
389 | }, | |
390 | .suspend = bfin_wdt_suspend, | |
391 | .resume = bfin_wdt_resume, | |
392 | }; | |
393 | ||
b47a166e | 394 | static const struct file_operations bfin_wdt_fops = { |
1e6d320f BW |
395 | .owner = THIS_MODULE, |
396 | .llseek = no_llseek, | |
397 | .write = bfin_wdt_write, | |
398 | .ioctl = bfin_wdt_ioctl, | |
399 | .open = bfin_wdt_open, | |
400 | .release = bfin_wdt_release, | |
401 | }; | |
402 | ||
403 | static struct miscdevice bfin_wdt_miscdev = { | |
404 | .minor = WATCHDOG_MINOR, | |
405 | .name = "watchdog", | |
406 | .fops = &bfin_wdt_fops, | |
407 | }; | |
408 | ||
409 | static struct watchdog_info bfin_wdt_info = { | |
410 | .identity = "Blackfin Watchdog", | |
411 | .options = WDIOF_SETTIMEOUT | | |
412 | WDIOF_KEEPALIVEPING | | |
413 | WDIOF_MAGICCLOSE, | |
414 | }; | |
415 | ||
416 | static struct notifier_block bfin_wdt_notifier = { | |
417 | .notifier_call = bfin_wdt_notify_sys, | |
418 | }; | |
419 | ||
420 | /** | |
421 | * bfin_wdt_init - Initialize module | |
422 | * | |
423 | * Registers the device and notifier handler. Actual device | |
424 | * initialization is handled by bfin_wdt_open(). | |
425 | */ | |
426 | static int __init bfin_wdt_init(void) | |
427 | { | |
428 | int ret; | |
429 | ||
430 | stampit(); | |
431 | ||
432 | /* Check that the timeout value is within range */ | |
433 | if (bfin_wdt_set_timeout(timeout)) | |
434 | return -EINVAL; | |
435 | ||
436 | /* Since this is an on-chip device and needs no board-specific | |
437 | * resources, we'll handle all the platform device stuff here. | |
438 | */ | |
439 | ret = platform_device_register(&bfin_wdt_device); | |
440 | if (ret) | |
441 | return ret; | |
442 | ||
443 | ret = platform_driver_probe(&bfin_wdt_driver, NULL); | |
444 | if (ret) | |
445 | return ret; | |
446 | ||
447 | ret = register_reboot_notifier(&bfin_wdt_notifier); | |
448 | if (ret) { | |
bb59b557 | 449 | pr_init(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", ret); |
1e6d320f BW |
450 | return ret; |
451 | } | |
452 | ||
453 | ret = misc_register(&bfin_wdt_miscdev); | |
454 | if (ret) { | |
bb59b557 | 455 | pr_init(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", |
1e6d320f BW |
456 | WATCHDOG_MINOR, ret); |
457 | unregister_reboot_notifier(&bfin_wdt_notifier); | |
458 | return ret; | |
459 | } | |
460 | ||
bb59b557 | 461 | pr_init(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n", |
1e6d320f BW |
462 | timeout, nowayout); |
463 | ||
464 | return 0; | |
465 | } | |
466 | ||
467 | /** | |
468 | * bfin_wdt_exit - Deinitialize module | |
469 | * | |
470 | * Unregisters the device and notifier handler. Actual device | |
471 | * deinitialization is handled by bfin_wdt_close(). | |
472 | */ | |
473 | static void __exit bfin_wdt_exit(void) | |
474 | { | |
475 | misc_deregister(&bfin_wdt_miscdev); | |
476 | unregister_reboot_notifier(&bfin_wdt_notifier); | |
477 | } | |
478 | ||
479 | module_init(bfin_wdt_init); | |
480 | module_exit(bfin_wdt_exit); | |
481 | ||
482 | MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>"); | |
483 | MODULE_DESCRIPTION("Blackfin Watchdog Device Driver"); | |
484 | MODULE_LICENSE("GPL"); | |
485 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
486 | ||
487 | module_param(timeout, uint, 0); | |
488 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
489 | ||
490 | module_param(nowayout, int, 0); | |
491 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |