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