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1da177e4 LT |
1 | /* linux/drivers/char/watchdog/s3c2410_wdt.c |
2 | * | |
3 | * Copyright (c) 2004 Simtec Electronics | |
4 | * Ben Dooks <ben@simtec.co.uk> | |
5 | * | |
6 | * S3C2410 Watchdog Timer Support | |
7 | * | |
8 | * Based on, softdog.c by Alan Cox, | |
9 | * (c) Copyright 1996 Alan Cox <alan@redhat.com> | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License as published by | |
13 | * the Free Software Foundation; either version 2 of the License, or | |
14 | * (at your option) any later version. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program; if not, write to the Free Software | |
23 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
24 | * | |
25 | * Changelog: | |
26 | * 05-Oct-2004 BJD Added semaphore init to stop crashes on open | |
27 | * Fixed tmr_count / wdt_count confusion | |
28 | * Added configurable debug | |
29 | * | |
af4bb822 BD |
30 | * 11-Jan-2005 BJD Fixed divide-by-2 in timeout code |
31 | * | |
32 | * 25-Jan-2005 DA Added suspend/resume support | |
1da177e4 LT |
33 | * |
34 | * 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA | |
35 | */ | |
36 | ||
37 | #include <linux/module.h> | |
38 | #include <linux/moduleparam.h> | |
39 | #include <linux/config.h> | |
40 | #include <linux/types.h> | |
41 | #include <linux/timer.h> | |
42 | #include <linux/miscdevice.h> | |
43 | #include <linux/watchdog.h> | |
44 | #include <linux/fs.h> | |
45 | #include <linux/notifier.h> | |
46 | #include <linux/reboot.h> | |
47 | #include <linux/init.h> | |
48 | #include <linux/device.h> | |
49 | #include <linux/interrupt.h> | |
50 | ||
51 | #include <asm/uaccess.h> | |
52 | #include <asm/io.h> | |
53 | ||
54 | #include <asm/arch/map.h> | |
55 | #include <asm/hardware/clock.h> | |
56 | ||
57 | #undef S3C24XX_VA_WATCHDOG | |
58 | #define S3C24XX_VA_WATCHDOG (0) | |
59 | ||
60 | #include <asm/arch/regs-watchdog.h> | |
61 | ||
62 | #define PFX "s3c2410-wdt: " | |
63 | ||
64 | #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0) | |
65 | #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15) | |
66 | ||
4bfdf378 | 67 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 LT |
68 | static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME; |
69 | static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT; | |
70 | static int soft_noboot = 0; | |
71 | static int debug = 0; | |
72 | ||
73 | module_param(tmr_margin, int, 0); | |
74 | module_param(tmr_atboot, int, 0); | |
75 | module_param(nowayout, int, 0); | |
76 | module_param(soft_noboot, int, 0); | |
77 | module_param(debug, int, 0); | |
78 | ||
79 | MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")"); | |
80 | ||
81 | MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT)); | |
82 | ||
83 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
84 | ||
85 | MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)"); | |
86 | ||
87 | MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)"); | |
88 | ||
89 | ||
90 | typedef enum close_state { | |
91 | CLOSE_STATE_NOT, | |
92 | CLOSE_STATE_ALLOW=0x4021 | |
93 | } close_state_t; | |
94 | ||
95 | static DECLARE_MUTEX(open_lock); | |
96 | ||
97 | static struct resource *wdt_mem; | |
98 | static struct resource *wdt_irq; | |
99 | static struct clk *wdt_clock; | |
100 | static void __iomem *wdt_base; | |
101 | static unsigned int wdt_count; | |
102 | static close_state_t allow_close; | |
103 | ||
104 | /* watchdog control routines */ | |
105 | ||
106 | #define DBG(msg...) do { \ | |
107 | if (debug) \ | |
108 | printk(KERN_INFO msg); \ | |
109 | } while(0) | |
110 | ||
111 | /* functions */ | |
112 | ||
113 | static int s3c2410wdt_keepalive(void) | |
114 | { | |
115 | writel(wdt_count, wdt_base + S3C2410_WTCNT); | |
116 | return 0; | |
117 | } | |
118 | ||
119 | static int s3c2410wdt_stop(void) | |
120 | { | |
121 | unsigned long wtcon; | |
122 | ||
123 | wtcon = readl(wdt_base + S3C2410_WTCON); | |
124 | wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN); | |
125 | writel(wtcon, wdt_base + S3C2410_WTCON); | |
126 | ||
127 | return 0; | |
128 | } | |
129 | ||
130 | static int s3c2410wdt_start(void) | |
131 | { | |
132 | unsigned long wtcon; | |
133 | ||
134 | s3c2410wdt_stop(); | |
135 | ||
136 | wtcon = readl(wdt_base + S3C2410_WTCON); | |
137 | wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128; | |
138 | ||
139 | if (soft_noboot) { | |
140 | wtcon |= S3C2410_WTCON_INTEN; | |
141 | wtcon &= ~S3C2410_WTCON_RSTEN; | |
142 | } else { | |
143 | wtcon &= ~S3C2410_WTCON_INTEN; | |
144 | wtcon |= S3C2410_WTCON_RSTEN; | |
145 | } | |
146 | ||
147 | DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n", | |
148 | __FUNCTION__, wdt_count, wtcon); | |
149 | ||
150 | writel(wdt_count, wdt_base + S3C2410_WTDAT); | |
151 | writel(wdt_count, wdt_base + S3C2410_WTCNT); | |
152 | writel(wtcon, wdt_base + S3C2410_WTCON); | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | static int s3c2410wdt_set_heartbeat(int timeout) | |
158 | { | |
159 | unsigned int freq = clk_get_rate(wdt_clock); | |
160 | unsigned int count; | |
161 | unsigned int divisor = 1; | |
162 | unsigned long wtcon; | |
163 | ||
164 | if (timeout < 1) | |
165 | return -EINVAL; | |
166 | ||
167 | freq /= 128; | |
168 | count = timeout * freq; | |
169 | ||
170 | DBG("%s: count=%d, timeout=%d, freq=%d\n", | |
171 | __FUNCTION__, count, timeout, freq); | |
172 | ||
173 | /* if the count is bigger than the watchdog register, | |
174 | then work out what we need to do (and if) we can | |
175 | actually make this value | |
176 | */ | |
177 | ||
178 | if (count >= 0x10000) { | |
179 | for (divisor = 1; divisor <= 0x100; divisor++) { | |
180 | if ((count / divisor) < 0x10000) | |
181 | break; | |
182 | } | |
183 | ||
184 | if ((count / divisor) >= 0x10000) { | |
185 | printk(KERN_ERR PFX "timeout %d too big\n", timeout); | |
186 | return -EINVAL; | |
187 | } | |
188 | } | |
189 | ||
190 | tmr_margin = timeout; | |
191 | ||
192 | DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n", | |
193 | __FUNCTION__, timeout, divisor, count, count/divisor); | |
194 | ||
195 | count /= divisor; | |
196 | wdt_count = count; | |
197 | ||
198 | /* update the pre-scaler */ | |
199 | wtcon = readl(wdt_base + S3C2410_WTCON); | |
200 | wtcon &= ~S3C2410_WTCON_PRESCALE_MASK; | |
201 | wtcon |= S3C2410_WTCON_PRESCALE(divisor-1); | |
202 | ||
203 | writel(count, wdt_base + S3C2410_WTDAT); | |
204 | writel(wtcon, wdt_base + S3C2410_WTCON); | |
205 | ||
206 | return 0; | |
207 | } | |
208 | ||
209 | /* | |
210 | * /dev/watchdog handling | |
211 | */ | |
212 | ||
213 | static int s3c2410wdt_open(struct inode *inode, struct file *file) | |
214 | { | |
215 | if(down_trylock(&open_lock)) | |
216 | return -EBUSY; | |
217 | ||
218 | if (nowayout) { | |
219 | __module_get(THIS_MODULE); | |
220 | } else { | |
221 | allow_close = CLOSE_STATE_ALLOW; | |
222 | } | |
223 | ||
224 | /* start the timer */ | |
225 | s3c2410wdt_start(); | |
226 | return nonseekable_open(inode, file); | |
227 | } | |
228 | ||
229 | static int s3c2410wdt_release(struct inode *inode, struct file *file) | |
230 | { | |
231 | /* | |
232 | * Shut off the timer. | |
233 | * Lock it in if it's a module and we set nowayout | |
234 | */ | |
235 | if (allow_close == CLOSE_STATE_ALLOW) { | |
236 | s3c2410wdt_stop(); | |
237 | } else { | |
238 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | |
239 | s3c2410wdt_keepalive(); | |
240 | } | |
241 | ||
242 | allow_close = CLOSE_STATE_NOT; | |
243 | up(&open_lock); | |
244 | return 0; | |
245 | } | |
246 | ||
247 | static ssize_t s3c2410wdt_write(struct file *file, const char __user *data, | |
248 | size_t len, loff_t *ppos) | |
249 | { | |
250 | /* | |
251 | * Refresh the timer. | |
252 | */ | |
253 | if(len) { | |
254 | if (!nowayout) { | |
255 | size_t i; | |
256 | ||
257 | /* In case it was set long ago */ | |
258 | allow_close = CLOSE_STATE_NOT; | |
259 | ||
260 | for (i = 0; i != len; i++) { | |
261 | char c; | |
262 | ||
263 | if (get_user(c, data + i)) | |
264 | return -EFAULT; | |
265 | if (c == 'V') | |
266 | allow_close = CLOSE_STATE_ALLOW; | |
267 | } | |
268 | } | |
269 | ||
270 | s3c2410wdt_keepalive(); | |
271 | } | |
272 | return len; | |
273 | } | |
274 | ||
275 | #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | |
276 | ||
277 | static struct watchdog_info s3c2410_wdt_ident = { | |
278 | .options = OPTIONS, | |
279 | .firmware_version = 0, | |
280 | .identity = "S3C2410 Watchdog", | |
281 | }; | |
282 | ||
283 | ||
284 | static int s3c2410wdt_ioctl(struct inode *inode, struct file *file, | |
285 | unsigned int cmd, unsigned long arg) | |
286 | { | |
287 | void __user *argp = (void __user *)arg; | |
288 | int __user *p = argp; | |
289 | int new_margin; | |
290 | ||
291 | switch (cmd) { | |
292 | default: | |
293 | return -ENOIOCTLCMD; | |
294 | ||
295 | case WDIOC_GETSUPPORT: | |
296 | return copy_to_user(argp, &s3c2410_wdt_ident, | |
297 | sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0; | |
298 | ||
299 | case WDIOC_GETSTATUS: | |
300 | case WDIOC_GETBOOTSTATUS: | |
301 | return put_user(0, p); | |
302 | ||
303 | case WDIOC_KEEPALIVE: | |
304 | s3c2410wdt_keepalive(); | |
305 | return 0; | |
306 | ||
307 | case WDIOC_SETTIMEOUT: | |
308 | if (get_user(new_margin, p)) | |
309 | return -EFAULT; | |
310 | ||
311 | if (s3c2410wdt_set_heartbeat(new_margin)) | |
312 | return -EINVAL; | |
313 | ||
314 | s3c2410wdt_keepalive(); | |
315 | return put_user(tmr_margin, p); | |
316 | ||
317 | case WDIOC_GETTIMEOUT: | |
318 | return put_user(tmr_margin, p); | |
319 | } | |
320 | } | |
321 | ||
322 | /* | |
323 | * Notifier for system down | |
324 | */ | |
325 | ||
326 | static int s3c2410wdt_notify_sys(struct notifier_block *this, unsigned long code, | |
327 | void *unused) | |
328 | { | |
329 | if(code==SYS_DOWN || code==SYS_HALT) { | |
330 | /* Turn the WDT off */ | |
331 | s3c2410wdt_stop(); | |
332 | } | |
333 | return NOTIFY_DONE; | |
334 | } | |
335 | ||
336 | /* kernel interface */ | |
337 | ||
338 | static struct file_operations s3c2410wdt_fops = { | |
339 | .owner = THIS_MODULE, | |
340 | .llseek = no_llseek, | |
341 | .write = s3c2410wdt_write, | |
342 | .ioctl = s3c2410wdt_ioctl, | |
343 | .open = s3c2410wdt_open, | |
344 | .release = s3c2410wdt_release, | |
345 | }; | |
346 | ||
347 | static struct miscdevice s3c2410wdt_miscdev = { | |
348 | .minor = WATCHDOG_MINOR, | |
349 | .name = "watchdog", | |
350 | .fops = &s3c2410wdt_fops, | |
351 | }; | |
352 | ||
353 | static struct notifier_block s3c2410wdt_notifier = { | |
354 | .notifier_call = s3c2410wdt_notify_sys, | |
355 | }; | |
356 | ||
357 | /* interrupt handler code */ | |
358 | ||
359 | static irqreturn_t s3c2410wdt_irq(int irqno, void *param, | |
360 | struct pt_regs *regs) | |
361 | { | |
362 | printk(KERN_INFO PFX "Watchdog timer expired!\n"); | |
363 | ||
364 | s3c2410wdt_keepalive(); | |
365 | return IRQ_HANDLED; | |
366 | } | |
367 | /* device interface */ | |
368 | ||
369 | static int s3c2410wdt_probe(struct device *dev) | |
370 | { | |
371 | struct platform_device *pdev = to_platform_device(dev); | |
372 | struct resource *res; | |
373 | int started = 0; | |
374 | int ret; | |
375 | int size; | |
376 | ||
377 | DBG("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev); | |
378 | ||
379 | /* get the memory region for the watchdog timer */ | |
380 | ||
381 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
382 | if (res == NULL) { | |
383 | printk(KERN_INFO PFX "failed to get memory region resouce\n"); | |
384 | return -ENOENT; | |
385 | } | |
386 | ||
387 | size = (res->end-res->start)+1; | |
388 | wdt_mem = request_mem_region(res->start, size, pdev->name); | |
389 | if (wdt_mem == NULL) { | |
390 | printk(KERN_INFO PFX "failed to get memory region\n"); | |
391 | return -ENOENT; | |
392 | } | |
393 | ||
394 | wdt_base = ioremap(res->start, size); | |
395 | if (wdt_base == 0) { | |
396 | printk(KERN_INFO PFX "failed to ioremap() region\n"); | |
397 | return -EINVAL; | |
398 | } | |
399 | ||
400 | DBG("probe: mapped wdt_base=%p\n", wdt_base); | |
401 | ||
402 | res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); | |
403 | if (res == NULL) { | |
404 | printk(KERN_INFO PFX "failed to get irq resource\n"); | |
405 | return -ENOENT; | |
406 | } | |
407 | ||
408 | ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, dev); | |
409 | if (ret != 0) { | |
410 | printk(KERN_INFO PFX "failed to install irq (%d)\n", ret); | |
411 | return ret; | |
412 | } | |
413 | ||
414 | wdt_clock = clk_get(dev, "watchdog"); | |
415 | if (wdt_clock == NULL) { | |
416 | printk(KERN_INFO PFX "failed to find watchdog clock source\n"); | |
417 | return -ENOENT; | |
418 | } | |
419 | ||
420 | clk_use(wdt_clock); | |
421 | clk_enable(wdt_clock); | |
422 | ||
423 | /* see if we can actually set the requested timer margin, and if | |
424 | * not, try the default value */ | |
425 | ||
426 | if (s3c2410wdt_set_heartbeat(tmr_margin)) { | |
427 | started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); | |
428 | ||
429 | if (started == 0) { | |
430 | printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n", | |
431 | CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); | |
432 | } else { | |
433 | printk(KERN_INFO PFX "default timer value is out of range, cannot start\n"); | |
434 | } | |
435 | } | |
436 | ||
437 | ret = register_reboot_notifier(&s3c2410wdt_notifier); | |
438 | if (ret) { | |
439 | printk (KERN_ERR PFX "cannot register reboot notifier (%d)\n", | |
440 | ret); | |
441 | return ret; | |
442 | } | |
443 | ||
444 | ret = misc_register(&s3c2410wdt_miscdev); | |
445 | if (ret) { | |
446 | printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n", | |
447 | WATCHDOG_MINOR, ret); | |
448 | unregister_reboot_notifier(&s3c2410wdt_notifier); | |
449 | return ret; | |
450 | } | |
451 | ||
452 | if (tmr_atboot && started == 0) { | |
453 | printk(KERN_INFO PFX "Starting Watchdog Timer\n"); | |
454 | s3c2410wdt_start(); | |
455 | } | |
456 | ||
457 | return 0; | |
458 | } | |
459 | ||
460 | static int s3c2410wdt_remove(struct device *dev) | |
461 | { | |
462 | if (wdt_mem != NULL) { | |
463 | release_resource(wdt_mem); | |
464 | kfree(wdt_mem); | |
465 | wdt_mem = NULL; | |
466 | } | |
467 | ||
468 | if (wdt_irq != NULL) { | |
469 | free_irq(wdt_irq->start, dev); | |
470 | wdt_irq = NULL; | |
471 | } | |
472 | ||
473 | if (wdt_clock != NULL) { | |
474 | clk_disable(wdt_clock); | |
475 | clk_unuse(wdt_clock); | |
476 | clk_put(wdt_clock); | |
477 | wdt_clock = NULL; | |
478 | } | |
479 | ||
480 | misc_deregister(&s3c2410wdt_miscdev); | |
481 | return 0; | |
482 | } | |
483 | ||
af4bb822 BD |
484 | #ifdef CONFIG_PM |
485 | ||
486 | static unsigned long wtcon_save; | |
487 | static unsigned long wtdat_save; | |
488 | ||
489 | static int s3c2410wdt_suspend(struct device *dev, u32 state, u32 level) | |
490 | { | |
491 | if (level == SUSPEND_POWER_DOWN) { | |
492 | /* Save watchdog state, and turn it off. */ | |
493 | wtcon_save = readl(wdt_base + S3C2410_WTCON); | |
494 | wtdat_save = readl(wdt_base + S3C2410_WTDAT); | |
495 | ||
496 | /* Note that WTCNT doesn't need to be saved. */ | |
497 | s3c2410wdt_stop(); | |
498 | } | |
499 | ||
500 | return 0; | |
501 | } | |
502 | ||
503 | static int s3c2410wdt_resume(struct device *dev, u32 level) | |
504 | { | |
505 | if (level == RESUME_POWER_ON) { | |
506 | /* Restore watchdog state. */ | |
507 | ||
508 | writel(wtdat_save, wdt_base + S3C2410_WTDAT); | |
509 | writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */ | |
510 | writel(wtcon_save, wdt_base + S3C2410_WTCON); | |
511 | ||
512 | printk(KERN_INFO PFX "watchdog %sabled\n", | |
513 | (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis"); | |
514 | } | |
515 | ||
516 | return 0; | |
517 | } | |
518 | ||
519 | #else | |
520 | #define s3c2410wdt_suspend NULL | |
521 | #define s3c2410wdt_resume NULL | |
522 | #endif /* CONFIG_PM */ | |
523 | ||
524 | ||
1da177e4 LT |
525 | static struct device_driver s3c2410wdt_driver = { |
526 | .name = "s3c2410-wdt", | |
527 | .bus = &platform_bus_type, | |
528 | .probe = s3c2410wdt_probe, | |
529 | .remove = s3c2410wdt_remove, | |
af4bb822 BD |
530 | .suspend = s3c2410wdt_suspend, |
531 | .resume = s3c2410wdt_resume, | |
1da177e4 LT |
532 | }; |
533 | ||
534 | ||
1da177e4 LT |
535 | static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n"; |
536 | ||
537 | static int __init watchdog_init(void) | |
538 | { | |
539 | printk(banner); | |
540 | return driver_register(&s3c2410wdt_driver); | |
541 | } | |
542 | ||
543 | static void __exit watchdog_exit(void) | |
544 | { | |
545 | driver_unregister(&s3c2410wdt_driver); | |
546 | unregister_reboot_notifier(&s3c2410wdt_notifier); | |
547 | } | |
548 | ||
549 | module_init(watchdog_init); | |
550 | module_exit(watchdog_exit); | |
551 | ||
af4bb822 BD |
552 | MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, " |
553 | "Dimitry Andric <dimitry.andric@tomtom.com>"); | |
1da177e4 LT |
554 | MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver"); |
555 | MODULE_LICENSE("GPL"); | |
556 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |