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920T: Use specific 920t mtune=
[linux-2.6/mini2440.git] / drivers / watchdog / s3c2410_wdt.c
blobe31925ee83462774ff573d4d4ae1d8d2ff538858
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@lxorguk.ukuu.org.uk>
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
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/types.h>
29 #include <linux/timer.h>
30 #include <linux/miscdevice.h>
31 #include <linux/watchdog.h>
32 #include <linux/fs.h>
33 #include <linux/init.h>
34 #include <linux/platform_device.h>
35 #include <linux/interrupt.h>
36 #include <linux/clk.h>
37 #include <linux/uaccess.h>
38 #include <linux/io.h>
39
40 #include <mach/map.h>
41
42 #undef S3C_VA_WATCHDOG
43 #define S3C_VA_WATCHDOG (0)
44
45 #include <plat/regs-watchdog.h>
46
47 #define PFX "s3c2410-wdt: "
48
49 #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
50 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
51
52 static int nowayout = WATCHDOG_NOWAYOUT;
53 static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
54 static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
55 static int soft_noboot;
56 static int debug;
57
58 module_param(tmr_margin, int, 0);
59 module_param(tmr_atboot, int, 0);
60 module_param(nowayout, int, 0);
61 module_param(soft_noboot, int, 0);
62 module_param(debug, int, 0);
63
64 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
65 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
66 MODULE_PARM_DESC(tmr_atboot,
67 "Watchdog is started at boot time if set to 1, default="
68 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
70 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
72 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
73
74
75 typedef enum close_state {
76 CLOSE_STATE_NOT,
77 CLOSE_STATE_ALLOW = 0x4021
78 } close_state_t;
79
80 static unsigned long open_lock;
81 static struct device *wdt_dev; /* platform device attached to */
82 static struct resource *wdt_mem;
83 static struct resource *wdt_irq;
84 static struct clk *wdt_clock;
85 static void __iomem *wdt_base;
86 static unsigned int wdt_count;
87 static close_state_t allow_close;
88 static DEFINE_SPINLOCK(wdt_lock);
89
90 /* watchdog control routines */
91
92 #define DBG(msg...) do { \
93 if (debug) \
94 printk(KERN_INFO msg); \
95 } while (0)
96
97 /* functions */
98
99 static void s3c2410wdt_keepalive(void)
100 {
101 spin_lock(&wdt_lock);
102 writel(wdt_count, wdt_base + S3C2410_WTCNT);
103 spin_unlock(&wdt_lock);
104 }
105
106 static void __s3c2410wdt_stop(void)
107 {
108 unsigned long wtcon;
109
110 wtcon = readl(wdt_base + S3C2410_WTCON);
111 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
112 writel(wtcon, wdt_base + S3C2410_WTCON);
113 }
114
115 static void s3c2410wdt_stop(void)
116 {
117 spin_lock(&wdt_lock);
118 __s3c2410wdt_stop();
119 spin_unlock(&wdt_lock);
120 }
121
122 static void s3c2410wdt_start(void)
123 {
124 unsigned long wtcon;
125
126 spin_lock(&wdt_lock);
127
128 __s3c2410wdt_stop();
129
130 wtcon = readl(wdt_base + S3C2410_WTCON);
131 wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
132
133 if (soft_noboot) {
134 wtcon |= S3C2410_WTCON_INTEN;
135 wtcon &= ~S3C2410_WTCON_RSTEN;
136 } else {
137 wtcon &= ~S3C2410_WTCON_INTEN;
138 wtcon |= S3C2410_WTCON_RSTEN;
139 }
140
141 DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
142 __func__, wdt_count, wtcon);
143
144 writel(wdt_count, wdt_base + S3C2410_WTDAT);
145 writel(wdt_count, wdt_base + S3C2410_WTCNT);
146 writel(wtcon, wdt_base + S3C2410_WTCON);
147 spin_unlock(&wdt_lock);
148 }
149
150 static int s3c2410wdt_set_heartbeat(int timeout)
151 {
152 unsigned int freq = clk_get_rate(wdt_clock);
153 unsigned int count;
154 unsigned int divisor = 1;
155 unsigned long wtcon;
156
157 if (timeout < 1)
158 return -EINVAL;
159
160 freq /= 128;
161 count = timeout * freq;
162
163 DBG("%s: count=%d, timeout=%d, freq=%d\n",
164 __func__, count, timeout, freq);
165
166 /* if the count is bigger than the watchdog register,
167 then work out what we need to do (and if) we can
168 actually make this value
169 */
170
171 if (count >= 0x10000) {
172 for (divisor = 1; divisor <= 0x100; divisor++) {
173 if ((count / divisor) < 0x10000)
174 break;
175 }
176
177 if ((count / divisor) >= 0x10000) {
178 dev_err(wdt_dev, "timeout %d too big\n", timeout);
179 return -EINVAL;
180 }
181 }
182
183 tmr_margin = timeout;
184
185 DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
186 __func__, timeout, divisor, count, count/divisor);
187
188 count /= divisor;
189 wdt_count = count;
190
191 /* update the pre-scaler */
192 wtcon = readl(wdt_base + S3C2410_WTCON);
193 wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
194 wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
195
196 writel(count, wdt_base + S3C2410_WTDAT);
197 writel(wtcon, wdt_base + S3C2410_WTCON);
198
199 return 0;
200 }
201
202 /*
203 * /dev/watchdog handling
204 */
205
206 static int s3c2410wdt_open(struct inode *inode, struct file *file)
207 {
208 if (test_and_set_bit(0, &open_lock))
209 return -EBUSY;
210
211 if (nowayout)
212 __module_get(THIS_MODULE);
213
214 allow_close = CLOSE_STATE_NOT;
215
216 /* start the timer */
217 s3c2410wdt_start();
218 return nonseekable_open(inode, file);
219 }
220
221 static int s3c2410wdt_release(struct inode *inode, struct file *file)
222 {
223 /*
224 * Shut off the timer.
225 * Lock it in if it's a module and we set nowayout
226 */
227
228 if (allow_close == CLOSE_STATE_ALLOW)
229 s3c2410wdt_stop();
230 else {
231 dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
232 s3c2410wdt_keepalive();
233 }
234 allow_close = CLOSE_STATE_NOT;
235 clear_bit(0, &open_lock);
236 return 0;
237 }
238
239 static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
240 size_t len, loff_t *ppos)
241 {
242 /*
243 * Refresh the timer.
244 */
245 if (len) {
246 if (!nowayout) {
247 size_t i;
248
249 /* In case it was set long ago */
250 allow_close = CLOSE_STATE_NOT;
251
252 for (i = 0; i != len; i++) {
253 char c;
254
255 if (get_user(c, data + i))
256 return -EFAULT;
257 if (c == 'V')
258 allow_close = CLOSE_STATE_ALLOW;
259 }
260 }
261 s3c2410wdt_keepalive();
262 }
263 return len;
264 }
265
266 #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
267
268 static const struct watchdog_info s3c2410_wdt_ident = {
269 .options = OPTIONS,
270 .firmware_version = 0,
271 .identity = "S3C2410 Watchdog",
272 };
273
274
275 static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
276 unsigned long arg)
277 {
278 void __user *argp = (void __user *)arg;
279 int __user *p = argp;
280 int new_margin;
281
282 switch (cmd) {
283 case WDIOC_GETSUPPORT:
284 return copy_to_user(argp, &s3c2410_wdt_ident,
285 sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
286 case WDIOC_GETSTATUS:
287 case WDIOC_GETBOOTSTATUS:
288 return put_user(0, p);
289 case WDIOC_KEEPALIVE:
290 s3c2410wdt_keepalive();
291 return 0;
292 case WDIOC_SETTIMEOUT:
293 if (get_user(new_margin, p))
294 return -EFAULT;
295 if (s3c2410wdt_set_heartbeat(new_margin))
296 return -EINVAL;
297 s3c2410wdt_keepalive();
298 return put_user(tmr_margin, p);
299 case WDIOC_GETTIMEOUT:
300 return put_user(tmr_margin, p);
301 default:
302 return -ENOTTY;
303 }
304 }
305
306 /* kernel interface */
307
308 static const struct file_operations s3c2410wdt_fops = {
309 .owner = THIS_MODULE,
310 .llseek = no_llseek,
311 .write = s3c2410wdt_write,
312 .unlocked_ioctl = s3c2410wdt_ioctl,
313 .open = s3c2410wdt_open,
314 .release = s3c2410wdt_release,
315 };
316
317 static struct miscdevice s3c2410wdt_miscdev = {
318 .minor = WATCHDOG_MINOR,
319 .name = "watchdog",
320 .fops = &s3c2410wdt_fops,
321 };
322
323 /* interrupt handler code */
324
325 static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
326 {
327 dev_info(wdt_dev, "watchdog timer expired (irq)\n");
328
329 s3c2410wdt_keepalive();
330 return IRQ_HANDLED;
331 }
332 /* device interface */
333
334 static int s3c2410wdt_probe(struct platform_device *pdev)
335 {
336 struct resource *res;
337 struct device *dev;
338 unsigned int wtcon;
339 int started = 0;
340 int ret;
341 int size;
342
343 DBG("%s: probe=%p\n", __func__, pdev);
344
345 dev = &pdev->dev;
346 wdt_dev = &pdev->dev;
347
348 /* get the memory region for the watchdog timer */
349
350 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
351 if (res == NULL) {
352 dev_err(dev, "no memory resource specified\n");
353 return -ENOENT;
354 }
355
356 size = (res->end - res->start) + 1;
357 wdt_mem = request_mem_region(res->start, size, pdev->name);
358 if (wdt_mem == NULL) {
359 dev_err(dev, "failed to get memory region\n");
360 ret = -ENOENT;
361 goto err_req;
362 }
363
364 wdt_base = ioremap(res->start, size);
365 if (wdt_base == NULL) {
366 dev_err(dev, "failed to ioremap() region\n");
367 ret = -EINVAL;
368 goto err_req;
369 }
370
371 DBG("probe: mapped wdt_base=%p\n", wdt_base);
372
373 wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
374 if (wdt_irq == NULL) {
375 dev_err(dev, "no irq resource specified\n");
376 ret = -ENOENT;
377 goto err_map;
378 }
379
380 ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
381 if (ret != 0) {
382 dev_err(dev, "failed to install irq (%d)\n", ret);
383 goto err_map;
384 }
385
386 wdt_clock = clk_get(&pdev->dev, "watchdog");
387 if (IS_ERR(wdt_clock)) {
388 dev_err(dev, "failed to find watchdog clock source\n");
389 ret = PTR_ERR(wdt_clock);
390 goto err_irq;
391 }
392
393 clk_enable(wdt_clock);
394
395 /* see if we can actually set the requested timer margin, and if
396 * not, try the default value */
397
398 if (s3c2410wdt_set_heartbeat(tmr_margin)) {
399 started = s3c2410wdt_set_heartbeat(
400 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
401
402 if (started == 0)
403 dev_info(dev,
404 "tmr_margin value out of range, default %d used\n",
405 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
406 else
407 dev_info(dev, "default timer value is out of range, cannot start\n");
408 }
409
410 ret = misc_register(&s3c2410wdt_miscdev);
411 if (ret) {
412 dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
413 WATCHDOG_MINOR, ret);
414 goto err_clk;
415 }
416
417 if (tmr_atboot && started == 0) {
418 dev_info(dev, "starting watchdog timer\n");
419 s3c2410wdt_start();
420 } else if (!tmr_atboot) {
421 /* if we're not enabling the watchdog, then ensure it is
422 * disabled if it has been left running from the bootloader
423 * or other source */
424
425 s3c2410wdt_stop();
426 }
427
428 /* print out a statement of readiness */
429
430 wtcon = readl(wdt_base + S3C2410_WTCON);
431
432 dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
433 (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
434 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
435 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
436
437 return 0;
438
439 err_clk:
440 clk_disable(wdt_clock);
441 clk_put(wdt_clock);
442
443 err_irq:
444 free_irq(wdt_irq->start, pdev);
445
446 err_map:
447 iounmap(wdt_base);
448
449 err_req:
450 release_resource(wdt_mem);
451 kfree(wdt_mem);
452
453 return ret;
454 }
455
456 static int s3c2410wdt_remove(struct platform_device *dev)
457 {
458 release_resource(wdt_mem);
459 kfree(wdt_mem);
460 wdt_mem = NULL;
461
462 free_irq(wdt_irq->start, dev);
463 wdt_irq = NULL;
464
465 clk_disable(wdt_clock);
466 clk_put(wdt_clock);
467 wdt_clock = NULL;
468
469 iounmap(wdt_base);
470 misc_deregister(&s3c2410wdt_miscdev);
471 return 0;
472 }
473
474 static void s3c2410wdt_shutdown(struct platform_device *dev)
475 {
476 s3c2410wdt_stop();
477 }
478
479 #ifdef CONFIG_PM
480
481 static unsigned long wtcon_save;
482 static unsigned long wtdat_save;
483
484 static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
485 {
486 /* Save watchdog state, and turn it off. */
487 wtcon_save = readl(wdt_base + S3C2410_WTCON);
488 wtdat_save = readl(wdt_base + S3C2410_WTDAT);
489
490 /* Note that WTCNT doesn't need to be saved. */
491 s3c2410wdt_stop();
492
493 return 0;
494 }
495
496 static int s3c2410wdt_resume(struct platform_device *dev)
497 {
498 /* Restore watchdog state. */
499
500 writel(wtdat_save, wdt_base + S3C2410_WTDAT);
501 writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
502 writel(wtcon_save, wdt_base + S3C2410_WTCON);
503
504 printk(KERN_INFO PFX "watchdog %sabled\n",
505 (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
506
507 return 0;
508 }
509
510 #else
511 #define s3c2410wdt_suspend NULL
512 #define s3c2410wdt_resume NULL
513 #endif /* CONFIG_PM */
514
515
516 static struct platform_driver s3c2410wdt_driver = {
517 .probe = s3c2410wdt_probe,
518 .remove = s3c2410wdt_remove,
519 .shutdown = s3c2410wdt_shutdown,
520 .suspend = s3c2410wdt_suspend,
521 .resume = s3c2410wdt_resume,
522 .driver = {
523 .owner = THIS_MODULE,
524 .name = "s3c2410-wdt",
525 },
526 };
527
528
529 static char banner[] __initdata =
530 KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
531
532 static int __init watchdog_init(void)
533 {
534 printk(banner);
535 return platform_driver_register(&s3c2410wdt_driver);
536 }
537
538 static void __exit watchdog_exit(void)
539 {
540 platform_driver_unregister(&s3c2410wdt_driver);
541 }
542
543 module_init(watchdog_init);
544 module_exit(watchdog_exit);
545
546 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
547 "Dimitry Andric <dimitry.andric@tomtom.com>");
548 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
549 MODULE_LICENSE("GPL");
550 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
551 MODULE_ALIAS("platform:s3c2410-wdt");
Support for the Chinese Samsung S3C2440 based development boards