watchdog: ep93xx_wdt.c fix default timout value in MODULE_PARM_DESC string.
[linux-2.6.git] / drivers / watchdog / s3c2410_wdt.c
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 #include <linux/cpufreq.h>
40 #include <linux/slab.h>
41
42 #include <mach/map.h>
43
44 #undef S3C_VA_WATCHDOG
45 #define S3C_VA_WATCHDOG (0)
46
47 #include <plat/regs-watchdog.h>
48
49 #define PFX "s3c2410-wdt: "
50
51 #define CONFIG_S3C2410_WATCHDOG_ATBOOT          (0)
52 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME    (15)
53
54 static int nowayout     = WATCHDOG_NOWAYOUT;
55 static int tmr_margin   = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
56 static int tmr_atboot   = CONFIG_S3C2410_WATCHDOG_ATBOOT;
57 static int soft_noboot;
58 static int debug;
59
60 module_param(tmr_margin,  int, 0);
61 module_param(tmr_atboot,  int, 0);
62 module_param(nowayout,    int, 0);
63 module_param(soft_noboot, int, 0);
64 module_param(debug,       int, 0);
65
66 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
67                 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
68 MODULE_PARM_DESC(tmr_atboot,
69                 "Watchdog is started at boot time if set to 1, default="
70                         __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
71 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
72                         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, "
74                         "0 to reboot (default depends on ONLY_TESTING)");
75 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
76
77 static unsigned long open_lock;
78 static struct device    *wdt_dev;       /* platform device attached to */
79 static struct resource  *wdt_mem;
80 static struct resource  *wdt_irq;
81 static struct clk       *wdt_clock;
82 static void __iomem     *wdt_base;
83 static unsigned int      wdt_count;
84 static char              expect_close;
85 static DEFINE_SPINLOCK(wdt_lock);
86
87 /* watchdog control routines */
88
89 #define DBG(msg...) do { \
90         if (debug) \
91                 printk(KERN_INFO msg); \
92         } while (0)
93
94 /* functions */
95
96 static void s3c2410wdt_keepalive(void)
97 {
98         spin_lock(&wdt_lock);
99         writel(wdt_count, wdt_base + S3C2410_WTCNT);
100         spin_unlock(&wdt_lock);
101 }
102
103 static void __s3c2410wdt_stop(void)
104 {
105         unsigned long wtcon;
106
107         wtcon = readl(wdt_base + S3C2410_WTCON);
108         wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
109         writel(wtcon, wdt_base + S3C2410_WTCON);
110 }
111
112 static void s3c2410wdt_stop(void)
113 {
114         spin_lock(&wdt_lock);
115         __s3c2410wdt_stop();
116         spin_unlock(&wdt_lock);
117 }
118
119 static void s3c2410wdt_start(void)
120 {
121         unsigned long wtcon;
122
123         spin_lock(&wdt_lock);
124
125         __s3c2410wdt_stop();
126
127         wtcon = readl(wdt_base + S3C2410_WTCON);
128         wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
129
130         if (soft_noboot) {
131                 wtcon |= S3C2410_WTCON_INTEN;
132                 wtcon &= ~S3C2410_WTCON_RSTEN;
133         } else {
134                 wtcon &= ~S3C2410_WTCON_INTEN;
135                 wtcon |= S3C2410_WTCON_RSTEN;
136         }
137
138         DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
139             __func__, wdt_count, wtcon);
140
141         writel(wdt_count, wdt_base + S3C2410_WTDAT);
142         writel(wdt_count, wdt_base + S3C2410_WTCNT);
143         writel(wtcon, wdt_base + S3C2410_WTCON);
144         spin_unlock(&wdt_lock);
145 }
146
147 static inline int s3c2410wdt_is_running(void)
148 {
149         return readl(wdt_base + S3C2410_WTCON) & S3C2410_WTCON_ENABLE;
150 }
151
152 static int s3c2410wdt_set_heartbeat(int timeout)
153 {
154         unsigned long freq = clk_get_rate(wdt_clock);
155         unsigned int count;
156         unsigned int divisor = 1;
157         unsigned long wtcon;
158
159         if (timeout < 1)
160                 return -EINVAL;
161
162         freq /= 128;
163         count = timeout * freq;
164
165         DBG("%s: count=%d, timeout=%d, freq=%lu\n",
166             __func__, count, timeout, freq);
167
168         /* if the count is bigger than the watchdog register,
169            then work out what we need to do (and if) we can
170            actually make this value
171         */
172
173         if (count >= 0x10000) {
174                 for (divisor = 1; divisor <= 0x100; divisor++) {
175                         if ((count / divisor) < 0x10000)
176                                 break;
177                 }
178
179                 if ((count / divisor) >= 0x10000) {
180                         dev_err(wdt_dev, "timeout %d too big\n", timeout);
181                         return -EINVAL;
182                 }
183         }
184
185         tmr_margin = timeout;
186
187         DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
188             __func__, timeout, divisor, count, count/divisor);
189
190         count /= divisor;
191         wdt_count = count;
192
193         /* update the pre-scaler */
194         wtcon = readl(wdt_base + S3C2410_WTCON);
195         wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
196         wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
197
198         writel(count, wdt_base + S3C2410_WTDAT);
199         writel(wtcon, wdt_base + S3C2410_WTCON);
200
201         return 0;
202 }
203
204 /*
205  *      /dev/watchdog handling
206  */
207
208 static int s3c2410wdt_open(struct inode *inode, struct file *file)
209 {
210         if (test_and_set_bit(0, &open_lock))
211                 return -EBUSY;
212
213         if (nowayout)
214                 __module_get(THIS_MODULE);
215
216         expect_close = 0;
217
218         /* start the timer */
219         s3c2410wdt_start();
220         return nonseekable_open(inode, file);
221 }
222
223 static int s3c2410wdt_release(struct inode *inode, struct file *file)
224 {
225         /*
226          *      Shut off the timer.
227          *      Lock it in if it's a module and we set nowayout
228          */
229
230         if (expect_close == 42)
231                 s3c2410wdt_stop();
232         else {
233                 dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
234                 s3c2410wdt_keepalive();
235         }
236         expect_close = 0;
237         clear_bit(0, &open_lock);
238         return 0;
239 }
240
241 static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
242                                 size_t len, loff_t *ppos)
243 {
244         /*
245          *      Refresh the timer.
246          */
247         if (len) {
248                 if (!nowayout) {
249                         size_t i;
250
251                         /* In case it was set long ago */
252                         expect_close = 0;
253
254                         for (i = 0; i != len; i++) {
255                                 char c;
256
257                                 if (get_user(c, data + i))
258                                         return -EFAULT;
259                                 if (c == 'V')
260                                         expect_close = 42;
261                         }
262                 }
263                 s3c2410wdt_keepalive();
264         }
265         return len;
266 }
267
268 #define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
269
270 static const struct watchdog_info s3c2410_wdt_ident = {
271         .options          =     OPTIONS,
272         .firmware_version =     0,
273         .identity         =     "S3C2410 Watchdog",
274 };
275
276
277 static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
278                                                         unsigned long arg)
279 {
280         void __user *argp = (void __user *)arg;
281         int __user *p = argp;
282         int new_margin;
283
284         switch (cmd) {
285         case WDIOC_GETSUPPORT:
286                 return copy_to_user(argp, &s3c2410_wdt_ident,
287                         sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
288         case WDIOC_GETSTATUS:
289         case WDIOC_GETBOOTSTATUS:
290                 return put_user(0, p);
291         case WDIOC_KEEPALIVE:
292                 s3c2410wdt_keepalive();
293                 return 0;
294         case WDIOC_SETTIMEOUT:
295                 if (get_user(new_margin, p))
296                         return -EFAULT;
297                 if (s3c2410wdt_set_heartbeat(new_margin))
298                         return -EINVAL;
299                 s3c2410wdt_keepalive();
300                 return put_user(tmr_margin, p);
301         case WDIOC_GETTIMEOUT:
302                 return put_user(tmr_margin, p);
303         default:
304                 return -ENOTTY;
305         }
306 }
307
308 /* kernel interface */
309
310 static const struct file_operations s3c2410wdt_fops = {
311         .owner          = THIS_MODULE,
312         .llseek         = no_llseek,
313         .write          = s3c2410wdt_write,
314         .unlocked_ioctl = s3c2410wdt_ioctl,
315         .open           = s3c2410wdt_open,
316         .release        = s3c2410wdt_release,
317 };
318
319 static struct miscdevice s3c2410wdt_miscdev = {
320         .minor          = WATCHDOG_MINOR,
321         .name           = "watchdog",
322         .fops           = &s3c2410wdt_fops,
323 };
324
325 /* interrupt handler code */
326
327 static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
328 {
329         dev_info(wdt_dev, "watchdog timer expired (irq)\n");
330
331         s3c2410wdt_keepalive();
332         return IRQ_HANDLED;
333 }
334
335
336 #ifdef CONFIG_CPU_FREQ
337
338 static int s3c2410wdt_cpufreq_transition(struct notifier_block *nb,
339                                           unsigned long val, void *data)
340 {
341         int ret;
342
343         if (!s3c2410wdt_is_running())
344                 goto done;
345
346         if (val == CPUFREQ_PRECHANGE) {
347                 /* To ensure that over the change we don't cause the
348                  * watchdog to trigger, we perform an keep-alive if
349                  * the watchdog is running.
350                  */
351
352                 s3c2410wdt_keepalive();
353         } else if (val == CPUFREQ_POSTCHANGE) {
354                 s3c2410wdt_stop();
355
356                 ret = s3c2410wdt_set_heartbeat(tmr_margin);
357
358                 if (ret >= 0)
359                         s3c2410wdt_start();
360                 else
361                         goto err;
362         }
363
364 done:
365         return 0;
366
367  err:
368         dev_err(wdt_dev, "cannot set new value for timeout %d\n", tmr_margin);
369         return ret;
370 }
371
372 static struct notifier_block s3c2410wdt_cpufreq_transition_nb = {
373         .notifier_call  = s3c2410wdt_cpufreq_transition,
374 };
375
376 static inline int s3c2410wdt_cpufreq_register(void)
377 {
378         return cpufreq_register_notifier(&s3c2410wdt_cpufreq_transition_nb,
379                                          CPUFREQ_TRANSITION_NOTIFIER);
380 }
381
382 static inline void s3c2410wdt_cpufreq_deregister(void)
383 {
384         cpufreq_unregister_notifier(&s3c2410wdt_cpufreq_transition_nb,
385                                     CPUFREQ_TRANSITION_NOTIFIER);
386 }
387
388 #else
389 static inline int s3c2410wdt_cpufreq_register(void)
390 {
391         return 0;
392 }
393
394 static inline void s3c2410wdt_cpufreq_deregister(void)
395 {
396 }
397 #endif
398
399
400
401 /* device interface */
402
403 static int __devinit s3c2410wdt_probe(struct platform_device *pdev)
404 {
405         struct resource *res;
406         struct device *dev;
407         unsigned int wtcon;
408         int started = 0;
409         int ret;
410         int size;
411
412         DBG("%s: probe=%p\n", __func__, pdev);
413
414         dev = &pdev->dev;
415         wdt_dev = &pdev->dev;
416
417         /* get the memory region for the watchdog timer */
418
419         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
420         if (res == NULL) {
421                 dev_err(dev, "no memory resource specified\n");
422                 return -ENOENT;
423         }
424
425         size = resource_size(res);
426         wdt_mem = request_mem_region(res->start, size, pdev->name);
427         if (wdt_mem == NULL) {
428                 dev_err(dev, "failed to get memory region\n");
429                 ret = -ENOENT;
430                 goto err_req;
431         }
432
433         wdt_base = ioremap(res->start, size);
434         if (wdt_base == NULL) {
435                 dev_err(dev, "failed to ioremap() region\n");
436                 ret = -EINVAL;
437                 goto err_req;
438         }
439
440         DBG("probe: mapped wdt_base=%p\n", wdt_base);
441
442         wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
443         if (wdt_irq == NULL) {
444                 dev_err(dev, "no irq resource specified\n");
445                 ret = -ENOENT;
446                 goto err_map;
447         }
448
449         ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
450         if (ret != 0) {
451                 dev_err(dev, "failed to install irq (%d)\n", ret);
452                 goto err_map;
453         }
454
455         wdt_clock = clk_get(&pdev->dev, "watchdog");
456         if (IS_ERR(wdt_clock)) {
457                 dev_err(dev, "failed to find watchdog clock source\n");
458                 ret = PTR_ERR(wdt_clock);
459                 goto err_irq;
460         }
461
462         clk_enable(wdt_clock);
463
464         if (s3c2410wdt_cpufreq_register() < 0) {
465                 printk(KERN_ERR PFX "failed to register cpufreq\n");
466                 goto err_clk;
467         }
468
469         /* see if we can actually set the requested timer margin, and if
470          * not, try the default value */
471
472         if (s3c2410wdt_set_heartbeat(tmr_margin)) {
473                 started = s3c2410wdt_set_heartbeat(
474                                         CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
475
476                 if (started == 0)
477                         dev_info(dev,
478                            "tmr_margin value out of range, default %d used\n",
479                                CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
480                 else
481                         dev_info(dev, "default timer value is out of range, "
482                                                         "cannot start\n");
483         }
484
485         ret = misc_register(&s3c2410wdt_miscdev);
486         if (ret) {
487                 dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
488                         WATCHDOG_MINOR, ret);
489                 goto err_cpufreq;
490         }
491
492         if (tmr_atboot && started == 0) {
493                 dev_info(dev, "starting watchdog timer\n");
494                 s3c2410wdt_start();
495         } else if (!tmr_atboot) {
496                 /* if we're not enabling the watchdog, then ensure it is
497                  * disabled if it has been left running from the bootloader
498                  * or other source */
499
500                 s3c2410wdt_stop();
501         }
502
503         /* print out a statement of readiness */
504
505         wtcon = readl(wdt_base + S3C2410_WTCON);
506
507         dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
508                  (wtcon & S3C2410_WTCON_ENABLE) ?  "" : "in",
509                  (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
510                  (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
511
512         return 0;
513
514  err_cpufreq:
515         s3c2410wdt_cpufreq_deregister();
516
517  err_clk:
518         clk_disable(wdt_clock);
519         clk_put(wdt_clock);
520
521  err_irq:
522         free_irq(wdt_irq->start, pdev);
523
524  err_map:
525         iounmap(wdt_base);
526
527  err_req:
528         release_resource(wdt_mem);
529         kfree(wdt_mem);
530
531         return ret;
532 }
533
534 static int __devexit s3c2410wdt_remove(struct platform_device *dev)
535 {
536         s3c2410wdt_cpufreq_deregister();
537
538         release_resource(wdt_mem);
539         kfree(wdt_mem);
540         wdt_mem = NULL;
541
542         free_irq(wdt_irq->start, dev);
543         wdt_irq = NULL;
544
545         clk_disable(wdt_clock);
546         clk_put(wdt_clock);
547         wdt_clock = NULL;
548
549         iounmap(wdt_base);
550         misc_deregister(&s3c2410wdt_miscdev);
551         return 0;
552 }
553
554 static void s3c2410wdt_shutdown(struct platform_device *dev)
555 {
556         s3c2410wdt_stop();
557 }
558
559 #ifdef CONFIG_PM
560
561 static unsigned long wtcon_save;
562 static unsigned long wtdat_save;
563
564 static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
565 {
566         /* Save watchdog state, and turn it off. */
567         wtcon_save = readl(wdt_base + S3C2410_WTCON);
568         wtdat_save = readl(wdt_base + S3C2410_WTDAT);
569
570         /* Note that WTCNT doesn't need to be saved. */
571         s3c2410wdt_stop();
572
573         return 0;
574 }
575
576 static int s3c2410wdt_resume(struct platform_device *dev)
577 {
578         /* Restore watchdog state. */
579
580         writel(wtdat_save, wdt_base + S3C2410_WTDAT);
581         writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
582         writel(wtcon_save, wdt_base + S3C2410_WTCON);
583
584         printk(KERN_INFO PFX "watchdog %sabled\n",
585                (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
586
587         return 0;
588 }
589
590 #else
591 #define s3c2410wdt_suspend NULL
592 #define s3c2410wdt_resume  NULL
593 #endif /* CONFIG_PM */
594
595
596 static struct platform_driver s3c2410wdt_driver = {
597         .probe          = s3c2410wdt_probe,
598         .remove         = __devexit_p(s3c2410wdt_remove),
599         .shutdown       = s3c2410wdt_shutdown,
600         .suspend        = s3c2410wdt_suspend,
601         .resume         = s3c2410wdt_resume,
602         .driver         = {
603                 .owner  = THIS_MODULE,
604                 .name   = "s3c2410-wdt",
605         },
606 };
607
608
609 static char banner[] __initdata =
610         KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
611
612 static int __init watchdog_init(void)
613 {
614         printk(banner);
615         return platform_driver_register(&s3c2410wdt_driver);
616 }
617
618 static void __exit watchdog_exit(void)
619 {
620         platform_driver_unregister(&s3c2410wdt_driver);
621 }
622
623 module_init(watchdog_init);
624 module_exit(watchdog_exit);
625
626 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
627               "Dimitry Andric <dimitry.andric@tomtom.com>");
628 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
629 MODULE_LICENSE("GPL");
630 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
631 MODULE_ALIAS("platform:s3c2410-wdt");