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Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target...
[linux-btrfs-devel.git] / drivers / watchdog / coh901327_wdt.c
blob9291506b8b235012fd9825f42bc2c6dad6c26f1b
1 /*
2 * coh901327_wdt.c
3 *
4 * Copyright (C) 2008-2009 ST-Ericsson AB
5 * License terms: GNU General Public License (GPL) version 2
6 * Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
7 * Author: Linus Walleij <linus.walleij@stericsson.com>
8 */
9 #include <linux/module.h>
10 #include <linux/types.h>
11 #include <linux/fs.h>
12 #include <linux/miscdevice.h>
13 #include <linux/watchdog.h>
14 #include <linux/interrupt.h>
15 #include <linux/pm.h>
16 #include <linux/platform_device.h>
17 #include <linux/io.h>
18 #include <linux/bitops.h>
19 #include <linux/uaccess.h>
20 #include <linux/clk.h>
21 #include <linux/delay.h>
22
23 #define DRV_NAME "WDOG COH 901 327"
24
25 /*
26 * COH 901 327 register definitions
27 */
28
29 /* WDOG_FEED Register 32bit (-/W) */
30 #define U300_WDOG_FR 0x00
31 #define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
32 /* WDOG_TIMEOUT Register 32bit (R/W) */
33 #define U300_WDOG_TR 0x04
34 #define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
35 /* WDOG_DISABLE1 Register 32bit (-/W) */
36 #define U300_WDOG_D1R 0x08
37 #define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
38 /* WDOG_DISABLE2 Register 32bit (R/W) */
39 #define U300_WDOG_D2R 0x0C
40 #define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
41 #define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
42 #define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
43 /* WDOG_STATUS Register 32bit (R/W) */
44 #define U300_WDOG_SR 0x10
45 #define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
46 #define U300_WDOG_SR_STATUS_NORMAL 0x0000U
47 #define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
48 /* WDOG_COUNT Register 32bit (R/-) */
49 #define U300_WDOG_CR 0x14
50 #define U300_WDOG_CR_VALID_IND 0x8000U
51 #define U300_WDOG_CR_VALID_STABLE 0x0000U
52 #define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
53 /* WDOG_JTAGOVR Register 32bit (R/W) */
54 #define U300_WDOG_JOR 0x18
55 #define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
56 #define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
57 /* WDOG_RESTART Register 32bit (-/W) */
58 #define U300_WDOG_RR 0x1C
59 #define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
60 /* WDOG_IRQ_EVENT Register 32bit (R/W) */
61 #define U300_WDOG_IER 0x20
62 #define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
63 #define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
64 /* WDOG_IRQ_MASK Register 32bit (R/W) */
65 #define U300_WDOG_IMR 0x24
66 #define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
67 /* WDOG_IRQ_FORCE Register 32bit (R/W) */
68 #define U300_WDOG_IFR 0x28
69 #define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
70
71 /* Default timeout in seconds = 1 minute */
72 static int margin = 60;
73 static resource_size_t phybase;
74 static resource_size_t physize;
75 static int irq;
76 static void __iomem *virtbase;
77 static unsigned long coh901327_users;
78 static unsigned long boot_status;
79 static u16 wdogenablestore;
80 static u16 irqmaskstore;
81 static struct device *parent;
82
83 /*
84 * The watchdog block is of course always clocked, the
85 * clk_enable()/clk_disable() calls are mainly for performing reference
86 * counting higher up in the clock hierarchy.
87 */
88 static struct clk *clk;
89
90 /*
91 * Enabling and disabling functions.
92 */
93 static void coh901327_enable(u16 timeout)
94 {
95 u16 val;
96 unsigned long freq;
97 unsigned long delay_ns;
98
99 clk_enable(clk);
100 /* Restart timer if it is disabled */
101 val = readw(virtbase + U300_WDOG_D2R);
102 if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
103 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
104 virtbase + U300_WDOG_RR);
105 /* Acknowledge any pending interrupt so it doesn't just fire off */
106 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
107 virtbase + U300_WDOG_IER);
108 /*
109 * The interrupt is cleared in the 32 kHz clock domain.
110 * Wait 3 32 kHz cycles for it to take effect
111 */
112 freq = clk_get_rate(clk);
113 delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
114 delay_ns = 3 * delay_ns; /* Wait 3 cycles */
115 ndelay(delay_ns);
116 /* Enable the watchdog interrupt */
117 writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
118 /* Activate the watchdog timer */
119 writew(timeout, virtbase + U300_WDOG_TR);
120 /* Start the watchdog timer */
121 writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
122 /*
123 * Extra read so that this change propagate in the watchdog.
124 */
125 (void) readw(virtbase + U300_WDOG_CR);
126 val = readw(virtbase + U300_WDOG_D2R);
127 clk_disable(clk);
128 if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
129 dev_err(parent,
130 "%s(): watchdog not enabled! D2R value %04x\n",
131 __func__, val);
132 }
133
134 static void coh901327_disable(void)
135 {
136 u16 val;
137
138 clk_enable(clk);
139 /* Disable the watchdog interrupt if it is active */
140 writew(0x0000U, virtbase + U300_WDOG_IMR);
141 /* If the watchdog is currently enabled, attempt to disable it */
142 val = readw(virtbase + U300_WDOG_D2R);
143 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
144 writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
145 virtbase + U300_WDOG_D1R);
146 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
147 virtbase + U300_WDOG_D2R);
148 /* Write this twice (else problems occur) */
149 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
150 virtbase + U300_WDOG_D2R);
151 }
152 val = readw(virtbase + U300_WDOG_D2R);
153 clk_disable(clk);
154 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
155 dev_err(parent,
156 "%s(): watchdog not disabled! D2R value %04x\n",
157 __func__, val);
158 }
159
160 static void coh901327_start(void)
161 {
162 coh901327_enable(margin * 100);
163 }
164
165 static void coh901327_keepalive(void)
166 {
167 clk_enable(clk);
168 /* Feed the watchdog */
169 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
170 virtbase + U300_WDOG_FR);
171 clk_disable(clk);
172 }
173
174 static int coh901327_settimeout(int time)
175 {
176 /*
177 * Max margin is 327 since the 10ms
178 * timeout register is max
179 * 0x7FFF = 327670ms ~= 327s.
180 */
181 if (time <= 0 || time > 327)
182 return -EINVAL;
183
184 margin = time;
185 clk_enable(clk);
186 /* Set new timeout value */
187 writew(margin * 100, virtbase + U300_WDOG_TR);
188 /* Feed the dog */
189 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
190 virtbase + U300_WDOG_FR);
191 clk_disable(clk);
192 return 0;
193 }
194
195 /*
196 * This interrupt occurs 10 ms before the watchdog WILL bark.
197 */
198 static irqreturn_t coh901327_interrupt(int irq, void *data)
199 {
200 u16 val;
201
202 /*
203 * Ack IRQ? If this occurs we're FUBAR anyway, so
204 * just acknowledge, disable the interrupt and await the imminent end.
205 * If you at some point need a host of callbacks to be called
206 * when the system is about to watchdog-reset, add them here!
207 *
208 * NOTE: on future versions of this IP-block, it will be possible
209 * to prevent a watchdog reset by feeding the watchdog at this
210 * point.
211 */
212 clk_enable(clk);
213 val = readw(virtbase + U300_WDOG_IER);
214 if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
215 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
216 virtbase + U300_WDOG_IER);
217 writew(0x0000U, virtbase + U300_WDOG_IMR);
218 clk_disable(clk);
219 dev_crit(parent, "watchdog is barking!\n");
220 return IRQ_HANDLED;
221 }
222
223 /*
224 * Allow only one user (daemon) to open the watchdog
225 */
226 static int coh901327_open(struct inode *inode, struct file *file)
227 {
228 if (test_and_set_bit(1, &coh901327_users))
229 return -EBUSY;
230 coh901327_start();
231 return nonseekable_open(inode, file);
232 }
233
234 static int coh901327_release(struct inode *inode, struct file *file)
235 {
236 clear_bit(1, &coh901327_users);
237 coh901327_disable();
238 return 0;
239 }
240
241 static ssize_t coh901327_write(struct file *file, const char __user *data,
242 size_t len, loff_t *ppos)
243 {
244 if (len)
245 coh901327_keepalive();
246 return len;
247 }
248
249 static long coh901327_ioctl(struct file *file, unsigned int cmd,
250 unsigned long arg)
251 {
252 int ret = -ENOTTY;
253 u16 val;
254 int time;
255 int new_options;
256 union {
257 struct watchdog_info __user *ident;
258 int __user *i;
259 } uarg;
260 static const struct watchdog_info ident = {
261 .options = WDIOF_CARDRESET |
262 WDIOF_SETTIMEOUT |
263 WDIOF_KEEPALIVEPING,
264 .identity = "COH 901 327 Watchdog",
265 .firmware_version = 1,
266 };
267 uarg.i = (int __user *)arg;
268
269 switch (cmd) {
270 case WDIOC_GETSUPPORT:
271 ret = copy_to_user(uarg.ident, &ident,
272 sizeof(ident)) ? -EFAULT : 0;
273 break;
274
275 case WDIOC_GETSTATUS:
276 ret = put_user(0, uarg.i);
277 break;
278
279 case WDIOC_GETBOOTSTATUS:
280 ret = put_user(boot_status, uarg.i);
281 break;
282
283 case WDIOC_SETOPTIONS:
284 ret = get_user(new_options, uarg.i);
285 if (ret)
286 break;
287 if (new_options & WDIOS_DISABLECARD)
288 coh901327_disable();
289 if (new_options & WDIOS_ENABLECARD)
290 coh901327_start();
291 ret = 0;
292 break;
293
294 case WDIOC_KEEPALIVE:
295 coh901327_keepalive();
296 ret = 0;
297 break;
298
299 case WDIOC_SETTIMEOUT:
300 ret = get_user(time, uarg.i);
301 if (ret)
302 break;
303
304 ret = coh901327_settimeout(time);
305 if (ret)
306 break;
307 /* Then fall through to return set value */
308
309 case WDIOC_GETTIMEOUT:
310 ret = put_user(margin, uarg.i);
311 break;
312
313 case WDIOC_GETTIMELEFT:
314 clk_enable(clk);
315 /* Read repeatedly until the value is stable! */
316 val = readw(virtbase + U300_WDOG_CR);
317 while (val & U300_WDOG_CR_VALID_IND)
318 val = readw(virtbase + U300_WDOG_CR);
319 val &= U300_WDOG_CR_COUNT_VALUE_MASK;
320 clk_disable(clk);
321 if (val != 0)
322 val /= 100;
323 ret = put_user(val, uarg.i);
324 break;
325 }
326 return ret;
327 }
328
329 static const struct file_operations coh901327_fops = {
330 .owner = THIS_MODULE,
331 .llseek = no_llseek,
332 .write = coh901327_write,
333 .unlocked_ioctl = coh901327_ioctl,
334 .open = coh901327_open,
335 .release = coh901327_release,
336 };
337
338 static struct miscdevice coh901327_miscdev = {
339 .minor = WATCHDOG_MINOR,
340 .name = "watchdog",
341 .fops = &coh901327_fops,
342 };
343
344 static int __exit coh901327_remove(struct platform_device *pdev)
345 {
346 misc_deregister(&coh901327_miscdev);
347 coh901327_disable();
348 free_irq(irq, pdev);
349 clk_put(clk);
350 iounmap(virtbase);
351 release_mem_region(phybase, physize);
352 return 0;
353 }
354
355
356 static int __init coh901327_probe(struct platform_device *pdev)
357 {
358 int ret;
359 u16 val;
360 struct resource *res;
361
362 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
363 if (!res)
364 return -ENOENT;
365
366 parent = &pdev->dev;
367 physize = resource_size(res);
368 phybase = res->start;
369
370 if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
371 ret = -EBUSY;
372 goto out;
373 }
374
375 virtbase = ioremap(phybase, physize);
376 if (!virtbase) {
377 ret = -ENOMEM;
378 goto out_no_remap;
379 }
380
381 clk = clk_get(&pdev->dev, NULL);
382 if (IS_ERR(clk)) {
383 ret = PTR_ERR(clk);
384 dev_err(&pdev->dev, "could not get clock\n");
385 goto out_no_clk;
386 }
387 ret = clk_enable(clk);
388 if (ret) {
389 dev_err(&pdev->dev, "could not enable clock\n");
390 goto out_no_clk_enable;
391 }
392
393 val = readw(virtbase + U300_WDOG_SR);
394 switch (val) {
395 case U300_WDOG_SR_STATUS_TIMED_OUT:
396 dev_info(&pdev->dev,
397 "watchdog timed out since last chip reset!\n");
398 boot_status = WDIOF_CARDRESET;
399 /* Status will be cleared below */
400 break;
401 case U300_WDOG_SR_STATUS_NORMAL:
402 dev_info(&pdev->dev,
403 "in normal status, no timeouts have occurred.\n");
404 break;
405 default:
406 dev_info(&pdev->dev,
407 "contains an illegal status code (%08x)\n", val);
408 break;
409 }
410
411 val = readw(virtbase + U300_WDOG_D2R);
412 switch (val) {
413 case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
414 dev_info(&pdev->dev, "currently disabled.\n");
415 break;
416 case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
417 dev_info(&pdev->dev,
418 "currently enabled! (disabling it now)\n");
419 coh901327_disable();
420 break;
421 default:
422 dev_err(&pdev->dev,
423 "contains an illegal enable/disable code (%08x)\n",
424 val);
425 break;
426 }
427
428 /* Reset the watchdog */
429 writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
430
431 irq = platform_get_irq(pdev, 0);
432 if (request_irq(irq, coh901327_interrupt, IRQF_DISABLED,
433 DRV_NAME " Bark", pdev)) {
434 ret = -EIO;
435 goto out_no_irq;
436 }
437
438 clk_disable(clk);
439
440 ret = misc_register(&coh901327_miscdev);
441 if (ret == 0)
442 dev_info(&pdev->dev,
443 "initialized. timer margin=%d sec\n", margin);
444 else
445 goto out_no_wdog;
446
447 return 0;
448
449 out_no_wdog:
450 free_irq(irq, pdev);
451 out_no_irq:
452 clk_disable(clk);
453 out_no_clk_enable:
454 clk_put(clk);
455 out_no_clk:
456 iounmap(virtbase);
457 out_no_remap:
458 release_mem_region(phybase, SZ_4K);
459 out:
460 return ret;
461 }
462
463 #ifdef CONFIG_PM
464 static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
465 {
466 irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
467 wdogenablestore = readw(virtbase + U300_WDOG_D2R);
468 /* If watchdog is on, disable it here and now */
469 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
470 coh901327_disable();
471 return 0;
472 }
473
474 static int coh901327_resume(struct platform_device *pdev)
475 {
476 /* Restore the watchdog interrupt */
477 writew(irqmaskstore, virtbase + U300_WDOG_IMR);
478 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
479 /* Restart the watchdog timer */
480 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
481 virtbase + U300_WDOG_RR);
482 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
483 virtbase + U300_WDOG_FR);
484 }
485 return 0;
486 }
487 #else
488 #define coh901327_suspend NULL
489 #define coh901327_resume NULL
490 #endif
491
492 /*
493 * Mistreating the watchdog is the only way to perform a software reset of the
494 * system on EMP platforms. So we implement this and export a symbol for it.
495 */
496 void coh901327_watchdog_reset(void)
497 {
498 /* Enable even if on JTAG too */
499 writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
500 virtbase + U300_WDOG_JOR);
501 /*
502 * Timeout = 5s, we have to wait for the watchdog reset to
503 * actually take place: the watchdog will be reloaded with the
504 * default value immediately, so we HAVE to reboot and get back
505 * into the kernel in 30s, or the device will reboot again!
506 * The boot loader will typically deactivate the watchdog, so we
507 * need time enough for the boot loader to get to the point of
508 * deactivating the watchdog before it is shut down by it.
509 *
510 * NOTE: on future versions of the watchdog, this restriction is
511 * gone: the watchdog will be reloaded with a default value (1 min)
512 * instead of last value, and you can conveniently set the watchdog
513 * timeout to 10ms (value = 1) without any problems.
514 */
515 coh901327_enable(500);
516 /* Return and await doom */
517 }
518
519 static struct platform_driver coh901327_driver = {
520 .driver = {
521 .owner = THIS_MODULE,
522 .name = "coh901327_wdog",
523 },
524 .remove = __exit_p(coh901327_remove),
525 .suspend = coh901327_suspend,
526 .resume = coh901327_resume,
527 };
528
529 static int __init coh901327_init(void)
530 {
531 return platform_driver_probe(&coh901327_driver, coh901327_probe);
532 }
533 module_init(coh901327_init);
534
535 static void __exit coh901327_exit(void)
536 {
537 platform_driver_unregister(&coh901327_driver);
538 }
539 module_exit(coh901327_exit);
540
541 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
542 MODULE_DESCRIPTION("COH 901 327 Watchdog");
543
544 module_param(margin, int, 0);
545 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
546
547 MODULE_LICENSE("GPL");
548 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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