Commit | Line | Data |
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1e6d320f BW |
1 | /* |
2 | * Blackfin On-Chip Watchdog Driver | |
1e6d320f BW |
3 | * |
4 | * Originally based on softdog.c | |
3dae93ec | 5 | * Copyright 2006-2010 Analog Devices Inc. |
1e6d320f | 6 | * Copyright 2006-2007 Michele d'Amico |
29fa0586 | 7 | * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk> |
1e6d320f BW |
8 | * |
9 | * Enter bugs at http://blackfin.uclinux.org/ | |
10 | * | |
11 | * Licensed under the GPL-2 or later. | |
12 | */ | |
13 | ||
14 | #include <linux/platform_device.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/moduleparam.h> | |
17 | #include <linux/types.h> | |
18 | #include <linux/timer.h> | |
19 | #include <linux/miscdevice.h> | |
20 | #include <linux/watchdog.h> | |
21 | #include <linux/fs.h> | |
1e6d320f BW |
22 | #include <linux/init.h> |
23 | #include <linux/interrupt.h> | |
9a5f50d3 | 24 | #include <linux/uaccess.h> |
089ab079 | 25 | #include <asm/blackfin.h> |
1e6d320f | 26 | |
a77dba7e WVS |
27 | #define stamp(fmt, args...) \ |
28 | pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) | |
1e6d320f | 29 | #define stampit() stamp("here i am") |
a77dba7e WVS |
30 | #define pr_devinit(fmt, args...) \ |
31 | ({ static const __devinitconst char __fmt[] = fmt; \ | |
32 | printk(__fmt, ## args); }) | |
33 | #define pr_init(fmt, args...) \ | |
34 | ({ static const __initconst char __fmt[] = fmt; \ | |
35 | printk(__fmt, ## args); }) | |
1e6d320f BW |
36 | |
37 | #define WATCHDOG_NAME "bfin-wdt" | |
38 | #define PFX WATCHDOG_NAME ": " | |
39 | ||
40 | /* The BF561 has two watchdogs (one per core), but since Linux | |
41 | * only runs on core A, we'll just work with that one. | |
42 | */ | |
43 | #ifdef BF561_FAMILY | |
44 | # define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL() | |
45 | # define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT() | |
46 | # define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT() | |
47 | # define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x) | |
48 | # define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x) | |
49 | # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x) | |
50 | #endif | |
51 | ||
52 | /* Bit in SWRST that indicates boot caused by watchdog */ | |
53 | #define SWRST_RESET_WDOG 0x4000 | |
54 | ||
55 | /* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */ | |
56 | #define WDOG_EXPIRED 0x8000 | |
57 | ||
58 | /* Masks for WDEV field in WDOG_CTL register */ | |
59 | #define ICTL_RESET 0x0 | |
60 | #define ICTL_NMI 0x2 | |
61 | #define ICTL_GPI 0x4 | |
62 | #define ICTL_NONE 0x6 | |
63 | #define ICTL_MASK 0x6 | |
64 | ||
65 | /* Masks for WDEN field in WDOG_CTL register */ | |
66 | #define WDEN_MASK 0x0FF0 | |
67 | #define WDEN_ENABLE 0x0000 | |
68 | #define WDEN_DISABLE 0x0AD0 | |
69 | ||
70 | /* some defaults */ | |
71 | #define WATCHDOG_TIMEOUT 20 | |
72 | ||
73 | static unsigned int timeout = WATCHDOG_TIMEOUT; | |
74 | static int nowayout = WATCHDOG_NOWAYOUT; | |
42747d71 | 75 | static const struct watchdog_info bfin_wdt_info; |
1e6d320f BW |
76 | static unsigned long open_check; |
77 | static char expect_close; | |
bf6350a3 | 78 | static DEFINE_SPINLOCK(bfin_wdt_spinlock); |
1e6d320f BW |
79 | |
80 | /** | |
81 | * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive | |
82 | * | |
83 | * The Userspace watchdog got a KeepAlive: schedule the next timeout. | |
84 | */ | |
85 | static int bfin_wdt_keepalive(void) | |
86 | { | |
87 | stampit(); | |
88 | bfin_write_WDOG_STAT(0); | |
89 | return 0; | |
90 | } | |
91 | ||
92 | /** | |
93 | * bfin_wdt_stop - Stop the Watchdog | |
94 | * | |
95 | * Stops the on-chip watchdog. | |
96 | */ | |
97 | static int bfin_wdt_stop(void) | |
98 | { | |
99 | stampit(); | |
100 | bfin_write_WDOG_CTL(WDEN_DISABLE); | |
101 | return 0; | |
102 | } | |
103 | ||
104 | /** | |
105 | * bfin_wdt_start - Start the Watchdog | |
106 | * | |
107 | * Starts the on-chip watchdog. Automatically loads WDOG_CNT | |
108 | * into WDOG_STAT for us. | |
109 | */ | |
110 | static int bfin_wdt_start(void) | |
111 | { | |
112 | stampit(); | |
113 | bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET); | |
114 | return 0; | |
115 | } | |
116 | ||
117 | /** | |
118 | * bfin_wdt_running - Check Watchdog status | |
119 | * | |
120 | * See if the watchdog is running. | |
121 | */ | |
122 | static int bfin_wdt_running(void) | |
123 | { | |
124 | stampit(); | |
125 | return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE); | |
126 | } | |
127 | ||
128 | /** | |
129 | * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout | |
130 | * @t: new timeout value (in seconds) | |
131 | * | |
132 | * Translate the specified timeout in seconds into System Clock | |
133 | * terms which is what the on-chip Watchdog requires. | |
134 | */ | |
135 | static int bfin_wdt_set_timeout(unsigned long t) | |
136 | { | |
3dae93ec | 137 | u32 cnt, max_t, sclk; |
1e6d320f BW |
138 | unsigned long flags; |
139 | ||
3dae93ec MF |
140 | sclk = get_sclk(); |
141 | max_t = -1 / sclk; | |
142 | cnt = t * sclk; | |
143 | stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt); | |
1e6d320f | 144 | |
3dae93ec | 145 | if (t > max_t) { |
1e6d320f BW |
146 | printk(KERN_WARNING PFX "timeout value is too large\n"); |
147 | return -EINVAL; | |
148 | } | |
149 | ||
150 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
151 | { | |
152 | int run = bfin_wdt_running(); | |
153 | bfin_wdt_stop(); | |
154 | bfin_write_WDOG_CNT(cnt); | |
9a5f50d3 AC |
155 | if (run) |
156 | bfin_wdt_start(); | |
1e6d320f BW |
157 | } |
158 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); | |
159 | ||
160 | timeout = t; | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | /** | |
166 | * bfin_wdt_open - Open the Device | |
167 | * @inode: inode of device | |
168 | * @file: file handle of device | |
169 | * | |
170 | * Watchdog device is opened and started. | |
171 | */ | |
172 | static int bfin_wdt_open(struct inode *inode, struct file *file) | |
173 | { | |
174 | stampit(); | |
175 | ||
176 | if (test_and_set_bit(0, &open_check)) | |
177 | return -EBUSY; | |
178 | ||
179 | if (nowayout) | |
180 | __module_get(THIS_MODULE); | |
181 | ||
182 | bfin_wdt_keepalive(); | |
183 | bfin_wdt_start(); | |
184 | ||
185 | return nonseekable_open(inode, file); | |
186 | } | |
187 | ||
188 | /** | |
189 | * bfin_wdt_close - Close the Device | |
190 | * @inode: inode of device | |
191 | * @file: file handle of device | |
192 | * | |
193 | * Watchdog device is closed and stopped. | |
194 | */ | |
195 | static int bfin_wdt_release(struct inode *inode, struct file *file) | |
196 | { | |
197 | stampit(); | |
198 | ||
9a5f50d3 | 199 | if (expect_close == 42) |
1e6d320f | 200 | bfin_wdt_stop(); |
9a5f50d3 AC |
201 | else { |
202 | printk(KERN_CRIT PFX | |
203 | "Unexpected close, not stopping watchdog!\n"); | |
1e6d320f BW |
204 | bfin_wdt_keepalive(); |
205 | } | |
1e6d320f BW |
206 | expect_close = 0; |
207 | clear_bit(0, &open_check); | |
1e6d320f BW |
208 | return 0; |
209 | } | |
210 | ||
211 | /** | |
212 | * bfin_wdt_write - Write to Device | |
213 | * @file: file handle of device | |
214 | * @buf: buffer to write | |
215 | * @count: length of buffer | |
216 | * @ppos: offset | |
217 | * | |
218 | * Pings the watchdog on write. | |
219 | */ | |
220 | static ssize_t bfin_wdt_write(struct file *file, const char __user *data, | |
9a5f50d3 | 221 | size_t len, loff_t *ppos) |
1e6d320f BW |
222 | { |
223 | stampit(); | |
224 | ||
225 | if (len) { | |
226 | if (!nowayout) { | |
227 | size_t i; | |
228 | ||
229 | /* In case it was set long ago */ | |
230 | expect_close = 0; | |
231 | ||
232 | for (i = 0; i != len; i++) { | |
233 | char c; | |
234 | if (get_user(c, data + i)) | |
235 | return -EFAULT; | |
236 | if (c == 'V') | |
237 | expect_close = 42; | |
238 | } | |
239 | } | |
240 | bfin_wdt_keepalive(); | |
241 | } | |
242 | ||
243 | return len; | |
244 | } | |
245 | ||
246 | /** | |
247 | * bfin_wdt_ioctl - Query Device | |
1e6d320f BW |
248 | * @file: file handle of device |
249 | * @cmd: watchdog command | |
250 | * @arg: argument | |
251 | * | |
252 | * Query basic information from the device or ping it, as outlined by the | |
253 | * watchdog API. | |
254 | */ | |
9a5f50d3 AC |
255 | static long bfin_wdt_ioctl(struct file *file, |
256 | unsigned int cmd, unsigned long arg) | |
1e6d320f BW |
257 | { |
258 | void __user *argp = (void __user *)arg; | |
259 | int __user *p = argp; | |
260 | ||
261 | stampit(); | |
262 | ||
263 | switch (cmd) { | |
9a5f50d3 AC |
264 | case WDIOC_GETSUPPORT: |
265 | if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info))) | |
266 | return -EFAULT; | |
267 | else | |
1e6d320f | 268 | return 0; |
9a5f50d3 AC |
269 | case WDIOC_GETSTATUS: |
270 | case WDIOC_GETBOOTSTATUS: | |
271 | return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p); | |
9a5f50d3 AC |
272 | case WDIOC_SETOPTIONS: { |
273 | unsigned long flags; | |
274 | int options, ret = -EINVAL; | |
275 | ||
276 | if (get_user(options, p)) | |
277 | return -EFAULT; | |
278 | ||
279 | spin_lock_irqsave(&bfin_wdt_spinlock, flags); | |
280 | if (options & WDIOS_DISABLECARD) { | |
281 | bfin_wdt_stop(); | |
282 | ret = 0; | |
1e6d320f | 283 | } |
9a5f50d3 AC |
284 | if (options & WDIOS_ENABLECARD) { |
285 | bfin_wdt_start(); | |
286 | ret = 0; | |
1e6d320f | 287 | } |
9a5f50d3 AC |
288 | spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); |
289 | return ret; | |
290 | } | |
0c06090c WVS |
291 | case WDIOC_KEEPALIVE: |
292 | bfin_wdt_keepalive(); | |
293 | return 0; | |
294 | case WDIOC_SETTIMEOUT: { | |
295 | int new_timeout; | |
296 | ||
297 | if (get_user(new_timeout, p)) | |
298 | return -EFAULT; | |
299 | if (bfin_wdt_set_timeout(new_timeout)) | |
300 | return -EINVAL; | |
301 | } | |
302 | /* Fall */ | |
303 | case WDIOC_GETTIMEOUT: | |
304 | return put_user(timeout, p); | |
9a5f50d3 AC |
305 | default: |
306 | return -ENOTTY; | |
1e6d320f BW |
307 | } |
308 | } | |
309 | ||
1e6d320f BW |
310 | #ifdef CONFIG_PM |
311 | static int state_before_suspend; | |
312 | ||
313 | /** | |
314 | * bfin_wdt_suspend - suspend the watchdog | |
315 | * @pdev: device being suspended | |
316 | * @state: requested suspend state | |
317 | * | |
318 | * Remember if the watchdog was running and stop it. | |
319 | * TODO: is this even right? Doesn't seem to be any | |
320 | * standard in the watchdog world ... | |
321 | */ | |
322 | static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state) | |
323 | { | |
324 | stampit(); | |
325 | ||
326 | state_before_suspend = bfin_wdt_running(); | |
327 | bfin_wdt_stop(); | |
328 | ||
329 | return 0; | |
330 | } | |
331 | ||
332 | /** | |
333 | * bfin_wdt_resume - resume the watchdog | |
334 | * @pdev: device being resumed | |
335 | * | |
336 | * If the watchdog was running, turn it back on. | |
337 | */ | |
338 | static int bfin_wdt_resume(struct platform_device *pdev) | |
339 | { | |
340 | stampit(); | |
341 | ||
342 | if (state_before_suspend) { | |
343 | bfin_wdt_set_timeout(timeout); | |
344 | bfin_wdt_start(); | |
345 | } | |
346 | ||
347 | return 0; | |
348 | } | |
349 | #else | |
350 | # define bfin_wdt_suspend NULL | |
351 | # define bfin_wdt_resume NULL | |
352 | #endif | |
353 | ||
b47a166e | 354 | static const struct file_operations bfin_wdt_fops = { |
9a5f50d3 AC |
355 | .owner = THIS_MODULE, |
356 | .llseek = no_llseek, | |
357 | .write = bfin_wdt_write, | |
358 | .unlocked_ioctl = bfin_wdt_ioctl, | |
359 | .open = bfin_wdt_open, | |
360 | .release = bfin_wdt_release, | |
1e6d320f BW |
361 | }; |
362 | ||
363 | static struct miscdevice bfin_wdt_miscdev = { | |
364 | .minor = WATCHDOG_MINOR, | |
365 | .name = "watchdog", | |
366 | .fops = &bfin_wdt_fops, | |
367 | }; | |
368 | ||
42747d71 | 369 | static const struct watchdog_info bfin_wdt_info = { |
1e6d320f BW |
370 | .identity = "Blackfin Watchdog", |
371 | .options = WDIOF_SETTIMEOUT | | |
9a5f50d3 AC |
372 | WDIOF_KEEPALIVEPING | |
373 | WDIOF_MAGICCLOSE, | |
1e6d320f BW |
374 | }; |
375 | ||
1e6d320f | 376 | /** |
93539b19 | 377 | * bfin_wdt_probe - Initialize module |
1e6d320f | 378 | * |
168b5251 | 379 | * Registers the misc device. Actual device |
1e6d320f BW |
380 | * initialization is handled by bfin_wdt_open(). |
381 | */ | |
93539b19 MF |
382 | static int __devinit bfin_wdt_probe(struct platform_device *pdev) |
383 | { | |
384 | int ret; | |
385 | ||
93539b19 MF |
386 | ret = misc_register(&bfin_wdt_miscdev); |
387 | if (ret) { | |
9a5f50d3 AC |
388 | pr_devinit(KERN_ERR PFX |
389 | "cannot register miscdev on minor=%d (err=%d)\n", | |
390 | WATCHDOG_MINOR, ret); | |
93539b19 MF |
391 | return ret; |
392 | } | |
393 | ||
394 | pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n", | |
395 | timeout, nowayout); | |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
400 | /** | |
401 | * bfin_wdt_remove - Initialize module | |
402 | * | |
168b5251 | 403 | * Unregisters the misc device. Actual device |
93539b19 MF |
404 | * deinitialization is handled by bfin_wdt_close(). |
405 | */ | |
406 | static int __devexit bfin_wdt_remove(struct platform_device *pdev) | |
407 | { | |
408 | misc_deregister(&bfin_wdt_miscdev); | |
93539b19 MF |
409 | return 0; |
410 | } | |
411 | ||
168b5251 WVS |
412 | /** |
413 | * bfin_wdt_shutdown - Soft Shutdown Handler | |
414 | * | |
415 | * Handles the soft shutdown event. | |
416 | */ | |
417 | static void bfin_wdt_shutdown(struct platform_device *pdev) | |
418 | { | |
419 | stampit(); | |
420 | ||
421 | bfin_wdt_stop(); | |
422 | } | |
423 | ||
93539b19 MF |
424 | static struct platform_device *bfin_wdt_device; |
425 | ||
426 | static struct platform_driver bfin_wdt_driver = { | |
427 | .probe = bfin_wdt_probe, | |
428 | .remove = __devexit_p(bfin_wdt_remove), | |
168b5251 | 429 | .shutdown = bfin_wdt_shutdown, |
93539b19 MF |
430 | .suspend = bfin_wdt_suspend, |
431 | .resume = bfin_wdt_resume, | |
432 | .driver = { | |
433 | .name = WATCHDOG_NAME, | |
434 | .owner = THIS_MODULE, | |
435 | }, | |
436 | }; | |
437 | ||
438 | /** | |
439 | * bfin_wdt_init - Initialize module | |
440 | * | |
441 | * Checks the module params and registers the platform device & driver. | |
442 | * Real work is in the platform probe function. | |
443 | */ | |
1e6d320f BW |
444 | static int __init bfin_wdt_init(void) |
445 | { | |
446 | int ret; | |
447 | ||
448 | stampit(); | |
449 | ||
450 | /* Check that the timeout value is within range */ | |
451 | if (bfin_wdt_set_timeout(timeout)) | |
452 | return -EINVAL; | |
453 | ||
454 | /* Since this is an on-chip device and needs no board-specific | |
455 | * resources, we'll handle all the platform device stuff here. | |
456 | */ | |
93539b19 | 457 | ret = platform_driver_register(&bfin_wdt_driver); |
1e6d320f | 458 | if (ret) { |
93539b19 | 459 | pr_init(KERN_ERR PFX "unable to register driver\n"); |
1e6d320f BW |
460 | return ret; |
461 | } | |
462 | ||
a77dba7e WVS |
463 | bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME, |
464 | -1, NULL, 0); | |
93539b19 MF |
465 | if (IS_ERR(bfin_wdt_device)) { |
466 | pr_init(KERN_ERR PFX "unable to register device\n"); | |
467 | platform_driver_unregister(&bfin_wdt_driver); | |
468 | return PTR_ERR(bfin_wdt_device); | |
1e6d320f BW |
469 | } |
470 | ||
1e6d320f BW |
471 | return 0; |
472 | } | |
473 | ||
474 | /** | |
475 | * bfin_wdt_exit - Deinitialize module | |
476 | * | |
93539b19 MF |
477 | * Back out the platform device & driver steps. Real work is in the |
478 | * platform remove function. | |
1e6d320f BW |
479 | */ |
480 | static void __exit bfin_wdt_exit(void) | |
481 | { | |
93539b19 MF |
482 | platform_device_unregister(bfin_wdt_device); |
483 | platform_driver_unregister(&bfin_wdt_driver); | |
1e6d320f BW |
484 | } |
485 | ||
486 | module_init(bfin_wdt_init); | |
487 | module_exit(bfin_wdt_exit); | |
488 | ||
489 | MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>"); | |
490 | MODULE_DESCRIPTION("Blackfin Watchdog Device Driver"); | |
491 | MODULE_LICENSE("GPL"); | |
492 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
493 | ||
494 | module_param(timeout, uint, 0); | |
9a5f50d3 AC |
495 | MODULE_PARM_DESC(timeout, |
496 | "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" | |
497 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
1e6d320f BW |
498 | |
499 | module_param(nowayout, int, 0); | |
9a5f50d3 AC |
500 | MODULE_PARM_DESC(nowayout, |
501 | "Watchdog cannot be stopped once started (default=" | |
502 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |