blob: fecb307d28e99162308025f7ba1b85c975f076f5 [file] [log] [blame]
Linus Walleij01480702009-05-06 15:35:40 +02001/*
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
22#define DRV_NAME "WDOG COH 901 327"
23
24/*
25 * COH 901 327 register definitions
26 */
27
28/* WDOG_FEED Register 32bit (-/W) */
29#define U300_WDOG_FR 0x00
30#define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
31/* WDOG_TIMEOUT Register 32bit (R/W) */
32#define U300_WDOG_TR 0x04
33#define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
34/* WDOG_DISABLE1 Register 32bit (-/W) */
35#define U300_WDOG_D1R 0x08
36#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
37/* WDOG_DISABLE2 Register 32bit (R/W) */
38#define U300_WDOG_D2R 0x0C
39#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
40#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
41#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
42/* WDOG_STATUS Register 32bit (R/W) */
43#define U300_WDOG_SR 0x10
44#define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
45#define U300_WDOG_SR_STATUS_NORMAL 0x0000U
46#define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
47/* WDOG_COUNT Register 32bit (R/-) */
48#define U300_WDOG_CR 0x14
49#define U300_WDOG_CR_VALID_IND 0x8000U
50#define U300_WDOG_CR_VALID_STABLE 0x0000U
51#define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
52/* WDOG_JTAGOVR Register 32bit (R/W) */
53#define U300_WDOG_JOR 0x18
54#define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
55#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
56/* WDOG_RESTART Register 32bit (-/W) */
57#define U300_WDOG_RR 0x1C
58#define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
59/* WDOG_IRQ_EVENT Register 32bit (R/W) */
60#define U300_WDOG_IER 0x20
61#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
62#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
63/* WDOG_IRQ_MASK Register 32bit (R/W) */
64#define U300_WDOG_IMR 0x24
65#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
66/* WDOG_IRQ_FORCE Register 32bit (R/W) */
67#define U300_WDOG_IFR 0x28
68#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
69
70/* Default timeout in seconds = 1 minute */
71static int margin = 60;
72static resource_size_t phybase;
73static resource_size_t physize;
74static int irq;
75static void __iomem *virtbase;
76static unsigned long coh901327_users;
77static unsigned long boot_status;
78static u16 wdogenablestore;
79static u16 irqmaskstore;
80static struct device *parent;
81
82/*
83 * The watchdog block is of course always clocked, the
84 * clk_enable()/clk_disable() calls are mainly for performing reference
85 * counting higher up in the clock hierarchy.
86 */
87static struct clk *clk;
88
89/*
90 * Enabling and disabling functions.
91 */
92static void coh901327_enable(u16 timeout)
93{
94 u16 val;
95
96 clk_enable(clk);
97 /* Restart timer if it is disabled */
98 val = readw(virtbase + U300_WDOG_D2R);
99 if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
100 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
101 virtbase + U300_WDOG_RR);
102 /* Acknowledge any pending interrupt so it doesn't just fire off */
103 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
104 virtbase + U300_WDOG_IER);
105 /* Enable the watchdog interrupt */
106 writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
107 /* Activate the watchdog timer */
108 writew(timeout, virtbase + U300_WDOG_TR);
109 /* Start the watchdog timer */
110 writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
111 /*
112 * Extra read so that this change propagate in the watchdog.
113 */
114 (void) readw(virtbase + U300_WDOG_CR);
115 val = readw(virtbase + U300_WDOG_D2R);
116 clk_disable(clk);
117 if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
118 dev_err(parent,
119 "%s(): watchdog not enabled! D2R value %04x\n",
120 __func__, val);
121}
122
123static void coh901327_disable(void)
124{
125 u16 val;
126
127 clk_enable(clk);
128 /* Disable the watchdog interrupt if it is active */
129 writew(0x0000U, virtbase + U300_WDOG_IMR);
130 /* If the watchdog is currently enabled, attempt to disable it */
131 val = readw(virtbase + U300_WDOG_D2R);
132 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
133 writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
134 virtbase + U300_WDOG_D1R);
135 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
136 virtbase + U300_WDOG_D2R);
137 /* Write this twice (else problems occur) */
138 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
139 virtbase + U300_WDOG_D2R);
140 }
141 val = readw(virtbase + U300_WDOG_D2R);
142 clk_disable(clk);
143 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
144 dev_err(parent,
145 "%s(): watchdog not disabled! D2R value %04x\n",
146 __func__, val);
147}
148
149static void coh901327_start(void)
150{
151 coh901327_enable(margin * 100);
152}
153
154static void coh901327_keepalive(void)
155{
156 clk_enable(clk);
157 /* Feed the watchdog */
158 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
159 virtbase + U300_WDOG_FR);
160 clk_disable(clk);
161}
162
163static int coh901327_settimeout(int time)
164{
165 /*
166 * Max margin is 327 since the 10ms
167 * timeout register is max
168 * 0x7FFF = 327670ms ~= 327s.
169 */
170 if (time <= 0 || time > 327)
171 return -EINVAL;
172
173 margin = time;
174 clk_enable(clk);
175 /* Set new timeout value */
176 writew(margin * 100, virtbase + U300_WDOG_TR);
177 /* Feed the dog */
178 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
179 virtbase + U300_WDOG_FR);
180 clk_disable(clk);
181 return 0;
182}
183
184/*
185 * This interrupt occurs 10 ms before the watchdog WILL bark.
186 */
187static irqreturn_t coh901327_interrupt(int irq, void *data)
188{
189 u16 val;
190
191 /*
192 * Ack IRQ? If this occurs we're FUBAR anyway, so
193 * just acknowledge, disable the interrupt and await the imminent end.
194 * If you at some point need a host of callbacks to be called
195 * when the system is about to watchdog-reset, add them here!
196 *
197 * NOTE: on future versions of this IP-block, it will be possible
198 * to prevent a watchdog reset by feeding the watchdog at this
199 * point.
200 */
201 clk_enable(clk);
202 val = readw(virtbase + U300_WDOG_IER);
203 if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
204 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
205 virtbase + U300_WDOG_IER);
206 writew(0x0000U, virtbase + U300_WDOG_IMR);
207 clk_disable(clk);
208 dev_crit(parent, "watchdog is barking!\n");
209 return IRQ_HANDLED;
210}
211
212/*
213 * Allow only one user (daemon) to open the watchdog
214 */
215static int coh901327_open(struct inode *inode, struct file *file)
216{
217 if (test_and_set_bit(1, &coh901327_users))
218 return -EBUSY;
219 coh901327_start();
220 return nonseekable_open(inode, file);
221}
222
223static int coh901327_release(struct inode *inode, struct file *file)
224{
225 clear_bit(1, &coh901327_users);
226 coh901327_disable();
227 return 0;
228}
229
230static ssize_t coh901327_write(struct file *file, const char __user *data,
231 size_t len, loff_t *ppos)
232{
233 if (len)
234 coh901327_keepalive();
235 return len;
236}
237
238static long coh901327_ioctl(struct file *file, unsigned int cmd,
239 unsigned long arg)
240{
241 int ret = -ENOTTY;
242 u16 val;
243 int time;
244 int new_options;
245 union {
246 struct watchdog_info __user *ident;
247 int __user *i;
248 } uarg;
249 static struct watchdog_info ident = {
250 .options = WDIOF_CARDRESET |
251 WDIOF_SETTIMEOUT |
252 WDIOF_KEEPALIVEPING,
253 .identity = "COH 901 327 Watchdog",
254 .firmware_version = 1,
255 };
256 uarg.i = (int __user *)arg;
257
258 switch (cmd) {
259 case WDIOC_GETSUPPORT:
260 ret = copy_to_user(uarg.ident, &ident,
261 sizeof(ident)) ? -EFAULT : 0;
262 break;
263
264 case WDIOC_GETSTATUS:
265 ret = put_user(0, uarg.i);
266 break;
267
268 case WDIOC_GETBOOTSTATUS:
269 ret = put_user(boot_status, uarg.i);
270 break;
271
272 case WDIOC_SETOPTIONS:
273 ret = get_user(new_options, uarg.i);
274 if (ret)
275 break;
276 if (new_options & WDIOS_DISABLECARD)
277 coh901327_disable();
278 if (new_options & WDIOS_ENABLECARD)
279 coh901327_start();
280 ret = 0;
281 break;
282
283 case WDIOC_KEEPALIVE:
284 coh901327_keepalive();
285 ret = 0;
286 break;
287
288 case WDIOC_SETTIMEOUT:
289 ret = get_user(time, uarg.i);
290 if (ret)
291 break;
292
293 ret = coh901327_settimeout(time);
294 if (ret)
295 break;
296 /* Then fall through to return set value */
297
298 case WDIOC_GETTIMEOUT:
299 ret = put_user(margin, uarg.i);
300 break;
301
302 case WDIOC_GETTIMELEFT:
303 clk_enable(clk);
304 /* Read repeatedly until the value is stable! */
305 val = readw(virtbase + U300_WDOG_CR);
306 while (val & U300_WDOG_CR_VALID_IND)
307 val = readw(virtbase + U300_WDOG_CR);
308 val &= U300_WDOG_CR_COUNT_VALUE_MASK;
309 clk_disable(clk);
310 if (val != 0)
311 val /= 100;
312 ret = put_user(val, uarg.i);
313 break;
314 }
315 return ret;
316}
317
318static const struct file_operations coh901327_fops = {
319 .owner = THIS_MODULE,
320 .llseek = no_llseek,
321 .write = coh901327_write,
322 .unlocked_ioctl = coh901327_ioctl,
323 .open = coh901327_open,
324 .release = coh901327_release,
325};
326
327static struct miscdevice coh901327_miscdev = {
328 .minor = WATCHDOG_MINOR,
329 .name = "watchdog",
330 .fops = &coh901327_fops,
331};
332
333static int __exit coh901327_remove(struct platform_device *pdev)
334{
335 misc_deregister(&coh901327_miscdev);
336 coh901327_disable();
337 free_irq(irq, pdev);
338 clk_put(clk);
339 iounmap(virtbase);
340 release_mem_region(phybase, physize);
341 return 0;
342}
343
344
345static int __init coh901327_probe(struct platform_device *pdev)
346{
347 int ret;
348 u16 val;
349 struct resource *res;
350
351 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
352 if (!res)
353 return -ENOENT;
354
355 parent = &pdev->dev;
356 physize = resource_size(res);
357 phybase = res->start;
358
359 if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
360 ret = -EBUSY;
361 goto out;
362 }
363
364 virtbase = ioremap(phybase, physize);
365 if (!virtbase) {
366 ret = -ENOMEM;
367 goto out_no_remap;
368 }
369
370 clk = clk_get(&pdev->dev, NULL);
371 if (IS_ERR(clk)) {
372 ret = PTR_ERR(clk);
373 dev_err(&pdev->dev, "could not get clock\n");
374 goto out_no_clk;
375 }
376 ret = clk_enable(clk);
377 if (ret) {
378 dev_err(&pdev->dev, "could not enable clock\n");
379 goto out_no_clk_enable;
380 }
381
382 val = readw(virtbase + U300_WDOG_SR);
383 switch (val) {
384 case U300_WDOG_SR_STATUS_TIMED_OUT:
385 dev_info(&pdev->dev,
386 "watchdog timed out since last chip reset!\n");
387 boot_status = WDIOF_CARDRESET;
388 /* Status will be cleared below */
389 break;
390 case U300_WDOG_SR_STATUS_NORMAL:
391 dev_info(&pdev->dev,
392 "in normal status, no timeouts have occurred.\n");
393 break;
394 default:
395 dev_info(&pdev->dev,
396 "contains an illegal status code (%08x)\n", val);
397 break;
398 }
399
400 val = readw(virtbase + U300_WDOG_D2R);
401 switch (val) {
402 case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
403 dev_info(&pdev->dev, "currently disabled.\n");
404 break;
405 case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
406 dev_info(&pdev->dev,
407 "currently enabled! (disabling it now)\n");
408 coh901327_disable();
409 break;
410 default:
411 dev_err(&pdev->dev,
412 "contains an illegal enable/disable code (%08x)\n",
413 val);
414 break;
415 }
416
417 /* Reset the watchdog */
418 writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
419
420 irq = platform_get_irq(pdev, 0);
421 if (request_irq(irq, coh901327_interrupt, IRQF_DISABLED,
422 DRV_NAME " Bark", pdev)) {
423 ret = -EIO;
424 goto out_no_irq;
425 }
426
427 clk_disable(clk);
428
429 ret = misc_register(&coh901327_miscdev);
430 if (ret == 0)
431 dev_info(&pdev->dev,
432 "initialized. timer margin=%d sec\n", margin);
433 else
434 goto out_no_wdog;
435
436 return 0;
437
438out_no_wdog:
439 free_irq(irq, pdev);
440out_no_irq:
441 clk_disable(clk);
442out_no_clk_enable:
443 clk_put(clk);
444out_no_clk:
445 iounmap(virtbase);
446out_no_remap:
447 release_mem_region(phybase, SZ_4K);
448out:
449 return ret;
450}
451
452#ifdef CONFIG_PM
453static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
454{
455 irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
456 wdogenablestore = readw(virtbase + U300_WDOG_D2R);
457 /* If watchdog is on, disable it here and now */
458 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
459 coh901327_disable();
460 return 0;
461}
462
463static int coh901327_resume(struct platform_device *pdev)
464{
465 /* Restore the watchdog interrupt */
466 writew(irqmaskstore, virtbase + U300_WDOG_IMR);
467 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
468 /* Restart the watchdog timer */
469 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
470 virtbase + U300_WDOG_RR);
471 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
472 virtbase + U300_WDOG_FR);
473 }
474 return 0;
475}
476#else
477#define coh901327_suspend NULL
478#define coh901327_resume NULL
479#endif
480
481/*
482 * Mistreating the watchdog is the only way to perform a software reset of the
483 * system on EMP platforms. So we implement this and export a symbol for it.
484 */
485void coh901327_watchdog_reset(void)
486{
487 /* Enable even if on JTAG too */
488 writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
489 virtbase + U300_WDOG_JOR);
490 /*
491 * Timeout = 5s, we have to wait for the watchdog reset to
492 * actually take place: the watchdog will be reloaded with the
493 * default value immediately, so we HAVE to reboot and get back
494 * into the kernel in 30s, or the device will reboot again!
495 * The boot loader will typically deactivate the watchdog, so we
496 * need time enough for the boot loader to get to the point of
497 * deactivating the watchdog before it is shut down by it.
498 *
499 * NOTE: on future versions of the watchdog, this restriction is
500 * gone: the watchdog will be reloaded with a defaul value (1 min)
501 * instead of last value, and you can conveniently set the watchdog
502 * timeout to 10ms (value = 1) without any problems.
503 */
504 coh901327_enable(500);
505 /* Return and await doom */
506}
507
508static struct platform_driver coh901327_driver = {
509 .driver = {
510 .owner = THIS_MODULE,
511 .name = "coh901327_wdog",
512 },
513 .remove = __exit_p(coh901327_remove),
514 .suspend = coh901327_suspend,
515 .resume = coh901327_resume,
516};
517
518static int __init coh901327_init(void)
519{
520 return platform_driver_probe(&coh901327_driver, coh901327_probe);
521}
522module_init(coh901327_init);
523
524static void __exit coh901327_exit(void)
525{
526 platform_driver_unregister(&coh901327_driver);
527}
528module_exit(coh901327_exit);
529
530MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
531MODULE_DESCRIPTION("COH 901 327 Watchdog");
532
533module_param(margin, int, 0);
534MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
535
536MODULE_LICENSE("GPL");
537MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);