diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/watchdog/s3c2410_wdt.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/watchdog/s3c2410_wdt.c')
-rw-r--r-- | drivers/char/watchdog/s3c2410_wdt.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/drivers/char/watchdog/s3c2410_wdt.c b/drivers/char/watchdog/s3c2410_wdt.c new file mode 100644 index 000000000000..1699d2c28ce5 --- /dev/null +++ b/drivers/char/watchdog/s3c2410_wdt.c | |||
@@ -0,0 +1,516 @@ | |||
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); | ||