[PATCH] DRIVER MODEL: Get rid of the obsolete tri-level suspend/resume callbacks
[linux-2.6.git] / drivers / char / 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@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-2005     BJD     Fixed divide-by-2 in timeout code
31  *
32  *      25-Jan-2005     DA      Added suspend/resume support
33  *                              Replaced reboot notifier with .shutdown method
34  *
35  *      10-Mar-2005     LCVR    Changed S3C2410_VA to S3C24XX_VA
36 */
37
38 #include <linux/module.h>
39 #include <linux/moduleparam.h>
40 #include <linux/config.h>
41 #include <linux/types.h>
42 #include <linux/timer.h>
43 #include <linux/miscdevice.h>
44 #include <linux/watchdog.h>
45 #include <linux/fs.h>
46 #include <linux/init.h>
47 #include <linux/device.h>
48 #include <linux/interrupt.h>
49
50 #include <asm/uaccess.h>
51 #include <asm/io.h>
52
53 #include <asm/arch/map.h>
54 #include <asm/hardware/clock.h>
55
56 #undef S3C24XX_VA_WATCHDOG
57 #define S3C24XX_VA_WATCHDOG (0)
58
59 #include <asm/arch/regs-watchdog.h>
60
61 #define PFX "s3c2410-wdt: "
62
63 #define CONFIG_S3C2410_WATCHDOG_ATBOOT          (0)
64 #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME    (15)
65
66 static int nowayout = WATCHDOG_NOWAYOUT;
67 static int tmr_margin   = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
68 static int tmr_atboot   = CONFIG_S3C2410_WATCHDOG_ATBOOT;
69 static int soft_noboot  = 0;
70 static int debug        = 0;
71
72 module_param(tmr_margin,  int, 0);
73 module_param(tmr_atboot,  int, 0);
74 module_param(nowayout,    int, 0);
75 module_param(soft_noboot, int, 0);
76 module_param(debug,       int, 0);
77
78 MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
79
80 MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
81
82 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
83
84 MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
85
86 MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
87
88
89 typedef enum close_state {
90         CLOSE_STATE_NOT,
91         CLOSE_STATE_ALLOW=0x4021
92 } close_state_t;
93
94 static DECLARE_MUTEX(open_lock);
95
96 static struct resource  *wdt_mem;
97 static struct resource  *wdt_irq;
98 static struct clk       *wdt_clock;
99 static void __iomem     *wdt_base;
100 static unsigned int      wdt_count;
101 static close_state_t     allow_close;
102
103 /* watchdog control routines */
104
105 #define DBG(msg...) do { \
106         if (debug) \
107                 printk(KERN_INFO msg); \
108         } while(0)
109
110 /* functions */
111
112 static int s3c2410wdt_keepalive(void)
113 {
114         writel(wdt_count, wdt_base + S3C2410_WTCNT);
115         return 0;
116 }
117
118 static int s3c2410wdt_stop(void)
119 {
120         unsigned long wtcon;
121
122         wtcon = readl(wdt_base + S3C2410_WTCON);
123         wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
124         writel(wtcon, wdt_base + S3C2410_WTCON);
125
126         return 0;
127 }
128
129 static int s3c2410wdt_start(void)
130 {
131         unsigned long wtcon;
132
133         s3c2410wdt_stop();
134
135         wtcon = readl(wdt_base + S3C2410_WTCON);
136         wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
137
138         if (soft_noboot) {
139                 wtcon |= S3C2410_WTCON_INTEN;
140                 wtcon &= ~S3C2410_WTCON_RSTEN;
141         } else {
142                 wtcon &= ~S3C2410_WTCON_INTEN;
143                 wtcon |= S3C2410_WTCON_RSTEN;
144         }
145
146         DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
147             __FUNCTION__, wdt_count, wtcon);
148
149         writel(wdt_count, wdt_base + S3C2410_WTDAT);
150         writel(wdt_count, wdt_base + S3C2410_WTCNT);
151         writel(wtcon, wdt_base + S3C2410_WTCON);
152
153         return 0;
154 }
155
156 static int s3c2410wdt_set_heartbeat(int timeout)
157 {
158         unsigned int freq = clk_get_rate(wdt_clock);
159         unsigned int count;
160         unsigned int divisor = 1;
161         unsigned long wtcon;
162
163         if (timeout < 1)
164                 return -EINVAL;
165
166         freq /= 128;
167         count = timeout * freq;
168
169         DBG("%s: count=%d, timeout=%d, freq=%d\n",
170             __FUNCTION__, count, timeout, freq);
171
172         /* if the count is bigger than the watchdog register,
173            then work out what we need to do (and if) we can
174            actually make this value
175         */
176
177         if (count >= 0x10000) {
178                 for (divisor = 1; divisor <= 0x100; divisor++) {
179                         if ((count / divisor) < 0x10000)
180                                 break;
181                 }
182
183                 if ((count / divisor) >= 0x10000) {
184                         printk(KERN_ERR PFX "timeout %d too big\n", timeout);
185                         return -EINVAL;
186                 }
187         }
188
189         tmr_margin = timeout;
190
191         DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
192             __FUNCTION__, timeout, divisor, count, count/divisor);
193
194         count /= divisor;
195         wdt_count = count;
196
197         /* update the pre-scaler */
198         wtcon = readl(wdt_base + S3C2410_WTCON);
199         wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
200         wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
201
202         writel(count, wdt_base + S3C2410_WTDAT);
203         writel(wtcon, wdt_base + S3C2410_WTCON);
204
205         return 0;
206 }
207
208 /*
209  *      /dev/watchdog handling
210  */
211
212 static int s3c2410wdt_open(struct inode *inode, struct file *file)
213 {
214         if(down_trylock(&open_lock))
215                 return -EBUSY;
216
217         if (nowayout) {
218                 __module_get(THIS_MODULE);
219         } else {
220                 allow_close = CLOSE_STATE_ALLOW;
221         }
222
223         /* start the timer */
224         s3c2410wdt_start();
225         return nonseekable_open(inode, file);
226 }
227
228 static int s3c2410wdt_release(struct inode *inode, struct file *file)
229 {
230         /*
231          *      Shut off the timer.
232          *      Lock it in if it's a module and we set nowayout
233          */
234         if (allow_close == CLOSE_STATE_ALLOW) {
235                 s3c2410wdt_stop();
236         } else {
237                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
238                 s3c2410wdt_keepalive();
239         }
240
241         allow_close = CLOSE_STATE_NOT;
242         up(&open_lock);
243         return 0;
244 }
245
246 static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
247                                 size_t len, loff_t *ppos)
248 {
249         /*
250          *      Refresh the timer.
251          */
252         if(len) {
253                 if (!nowayout) {
254                         size_t i;
255
256                         /* In case it was set long ago */
257                         allow_close = CLOSE_STATE_NOT;
258
259                         for (i = 0; i != len; i++) {
260                                 char c;
261
262                                 if (get_user(c, data + i))
263                                         return -EFAULT;
264                                 if (c == 'V')
265                                         allow_close = CLOSE_STATE_ALLOW;
266                         }
267                 }
268
269                 s3c2410wdt_keepalive();
270         }
271         return len;
272 }
273
274 #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
275
276 static struct watchdog_info s3c2410_wdt_ident = {
277         .options          =     OPTIONS,
278         .firmware_version =     0,
279         .identity         =     "S3C2410 Watchdog",
280 };
281
282
283 static int s3c2410wdt_ioctl(struct inode *inode, struct file *file,
284         unsigned int cmd, unsigned long arg)
285 {
286         void __user *argp = (void __user *)arg;
287         int __user *p = argp;
288         int new_margin;
289
290         switch (cmd) {
291                 default:
292                         return -ENOIOCTLCMD;
293
294                 case WDIOC_GETSUPPORT:
295                         return copy_to_user(argp, &s3c2410_wdt_ident,
296                                 sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
297
298                 case WDIOC_GETSTATUS:
299                 case WDIOC_GETBOOTSTATUS:
300                         return put_user(0, p);
301
302                 case WDIOC_KEEPALIVE:
303                         s3c2410wdt_keepalive();
304                         return 0;
305
306                 case WDIOC_SETTIMEOUT:
307                         if (get_user(new_margin, p))
308                                 return -EFAULT;
309
310                         if (s3c2410wdt_set_heartbeat(new_margin))
311                                 return -EINVAL;
312
313                         s3c2410wdt_keepalive();
314                         return put_user(tmr_margin, p);
315
316                 case WDIOC_GETTIMEOUT:
317                         return put_user(tmr_margin, p);
318         }
319 }
320
321 /* kernel interface */
322
323 static struct file_operations s3c2410wdt_fops = {
324         .owner          = THIS_MODULE,
325         .llseek         = no_llseek,
326         .write          = s3c2410wdt_write,
327         .ioctl          = s3c2410wdt_ioctl,
328         .open           = s3c2410wdt_open,
329         .release        = s3c2410wdt_release,
330 };
331
332 static struct miscdevice s3c2410wdt_miscdev = {
333         .minor          = WATCHDOG_MINOR,
334         .name           = "watchdog",
335         .fops           = &s3c2410wdt_fops,
336 };
337
338 /* interrupt handler code */
339
340 static irqreturn_t s3c2410wdt_irq(int irqno, void *param,
341                                   struct pt_regs *regs)
342 {
343         printk(KERN_INFO PFX "Watchdog timer expired!\n");
344
345         s3c2410wdt_keepalive();
346         return IRQ_HANDLED;
347 }
348 /* device interface */
349
350 static int s3c2410wdt_probe(struct device *dev)
351 {
352         struct platform_device *pdev = to_platform_device(dev);
353         struct resource *res;
354         int started = 0;
355         int ret;
356         int size;
357
358         DBG("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev);
359
360         /* get the memory region for the watchdog timer */
361
362         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
363         if (res == NULL) {
364                 printk(KERN_INFO PFX "failed to get memory region resouce\n");
365                 return -ENOENT;
366         }
367
368         size = (res->end-res->start)+1;
369         wdt_mem = request_mem_region(res->start, size, pdev->name);
370         if (wdt_mem == NULL) {
371                 printk(KERN_INFO PFX "failed to get memory region\n");
372                 return -ENOENT;
373         }
374
375         wdt_base = ioremap(res->start, size);
376         if (wdt_base == 0) {
377                 printk(KERN_INFO PFX "failed to ioremap() region\n");
378                 return -EINVAL;
379         }
380
381         DBG("probe: mapped wdt_base=%p\n", wdt_base);
382
383         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
384         if (res == NULL) {
385                 printk(KERN_INFO PFX "failed to get irq resource\n");
386                 return -ENOENT;
387         }
388
389         ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, dev);
390         if (ret != 0) {
391                 printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);
392                 return ret;
393         }
394
395         wdt_clock = clk_get(dev, "watchdog");
396         if (wdt_clock == NULL) {
397                 printk(KERN_INFO PFX "failed to find watchdog clock source\n");
398                 return -ENOENT;
399         }
400
401         clk_use(wdt_clock);
402         clk_enable(wdt_clock);
403
404         /* see if we can actually set the requested timer margin, and if
405          * not, try the default value */
406
407         if (s3c2410wdt_set_heartbeat(tmr_margin)) {
408                 started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
409
410                 if (started == 0) {
411                         printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n",
412                                CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
413                 } else {
414                         printk(KERN_INFO PFX "default timer value is out of range, cannot start\n");
415                 }
416         }
417
418         ret = misc_register(&s3c2410wdt_miscdev);
419         if (ret) {
420                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n",
421                         WATCHDOG_MINOR, ret);
422                 return ret;
423         }
424
425         if (tmr_atboot && started == 0) {
426                 printk(KERN_INFO PFX "Starting Watchdog Timer\n");
427                 s3c2410wdt_start();
428         }
429
430         return 0;
431 }
432
433 static int s3c2410wdt_remove(struct device *dev)
434 {
435         if (wdt_mem != NULL) {
436                 release_resource(wdt_mem);
437                 kfree(wdt_mem);
438                 wdt_mem = NULL;
439         }
440
441         if (wdt_irq != NULL) {
442                 free_irq(wdt_irq->start, dev);
443                 wdt_irq = NULL;
444         }
445
446         if (wdt_clock != NULL) {
447                 clk_disable(wdt_clock);
448                 clk_unuse(wdt_clock);
449                 clk_put(wdt_clock);
450                 wdt_clock = NULL;
451         }
452
453         misc_deregister(&s3c2410wdt_miscdev);
454         return 0;
455 }
456
457 static void s3c2410wdt_shutdown(struct device *dev)
458 {
459         s3c2410wdt_stop();      
460 }
461
462 #ifdef CONFIG_PM
463
464 static unsigned long wtcon_save;
465 static unsigned long wtdat_save;
466
467 static int s3c2410wdt_suspend(struct device *dev, pm_message_t state)
468 {
469         /* Save watchdog state, and turn it off. */
470         wtcon_save = readl(wdt_base + S3C2410_WTCON);
471         wtdat_save = readl(wdt_base + S3C2410_WTDAT);
472
473         /* Note that WTCNT doesn't need to be saved. */
474         s3c2410wdt_stop();
475
476         return 0;
477 }
478
479 static int s3c2410wdt_resume(struct device *dev)
480 {
481         /* Restore watchdog state. */
482
483         writel(wtdat_save, wdt_base + S3C2410_WTDAT);
484         writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
485         writel(wtcon_save, wdt_base + S3C2410_WTCON);
486
487         printk(KERN_INFO PFX "watchdog %sabled\n",
488                (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
489
490         return 0;
491 }
492
493 #else
494 #define s3c2410wdt_suspend NULL
495 #define s3c2410wdt_resume  NULL
496 #endif /* CONFIG_PM */
497
498
499 static struct device_driver s3c2410wdt_driver = {
500         .name           = "s3c2410-wdt",
501         .bus            = &platform_bus_type,
502         .probe          = s3c2410wdt_probe,
503         .remove         = s3c2410wdt_remove,
504         .shutdown       = s3c2410wdt_shutdown,
505         .suspend        = s3c2410wdt_suspend,
506         .resume         = s3c2410wdt_resume,
507 };
508
509
510 static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
511
512 static int __init watchdog_init(void)
513 {
514         printk(banner);
515         return driver_register(&s3c2410wdt_driver);
516 }
517
518 static void __exit watchdog_exit(void)
519 {
520         driver_unregister(&s3c2410wdt_driver);
521 }
522
523 module_init(watchdog_init);
524 module_exit(watchdog_exit);
525
526 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
527               "Dimitry Andric <dimitry.andric@tomtom.com>");
528 MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
529 MODULE_LICENSE("GPL");
530 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);