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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>
Linus Walleij01480702009-05-06 15:35:40 +020011#include <linux/watchdog.h>
12#include <linux/interrupt.h>
13#include <linux/pm.h>
14#include <linux/platform_device.h>
15#include <linux/io.h>
16#include <linux/bitops.h>
Linus Walleij01480702009-05-06 15:35:40 +020017#include <linux/clk.h>
Linus Walleij5973bee2009-07-21 00:40:46 +020018#include <linux/delay.h>
Linus Walleij15b25702012-03-16 09:14:12 +010019#include <linux/err.h>
Linus Walleij01480702009-05-06 15:35:40 +020020
21#define DRV_NAME "WDOG COH 901 327"
22
23/*
24 * COH 901 327 register definitions
25 */
26
27/* WDOG_FEED Register 32bit (-/W) */
28#define U300_WDOG_FR 0x00
29#define U300_WDOG_FR_FEED_RESTART_TIMER 0xFEEDU
30/* WDOG_TIMEOUT Register 32bit (R/W) */
31#define U300_WDOG_TR 0x04
32#define U300_WDOG_TR_TIMEOUT_MASK 0x7FFFU
33/* WDOG_DISABLE1 Register 32bit (-/W) */
34#define U300_WDOG_D1R 0x08
35#define U300_WDOG_D1R_DISABLE1_DISABLE_TIMER 0x2BADU
36/* WDOG_DISABLE2 Register 32bit (R/W) */
37#define U300_WDOG_D2R 0x0C
38#define U300_WDOG_D2R_DISABLE2_DISABLE_TIMER 0xCAFEU
39#define U300_WDOG_D2R_DISABLE_STATUS_DISABLED 0xDABEU
40#define U300_WDOG_D2R_DISABLE_STATUS_ENABLED 0x0000U
41/* WDOG_STATUS Register 32bit (R/W) */
42#define U300_WDOG_SR 0x10
43#define U300_WDOG_SR_STATUS_TIMED_OUT 0xCFE8U
44#define U300_WDOG_SR_STATUS_NORMAL 0x0000U
45#define U300_WDOG_SR_RESET_STATUS_RESET 0xE8B4U
46/* WDOG_COUNT Register 32bit (R/-) */
47#define U300_WDOG_CR 0x14
48#define U300_WDOG_CR_VALID_IND 0x8000U
49#define U300_WDOG_CR_VALID_STABLE 0x0000U
50#define U300_WDOG_CR_COUNT_VALUE_MASK 0x7FFFU
51/* WDOG_JTAGOVR Register 32bit (R/W) */
52#define U300_WDOG_JOR 0x18
53#define U300_WDOG_JOR_JTAG_MODE_IND 0x0002U
54#define U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE 0x0001U
55/* WDOG_RESTART Register 32bit (-/W) */
56#define U300_WDOG_RR 0x1C
57#define U300_WDOG_RR_RESTART_VALUE_RESUME 0xACEDU
58/* WDOG_IRQ_EVENT Register 32bit (R/W) */
59#define U300_WDOG_IER 0x20
60#define U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND 0x0001U
61#define U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE 0x0001U
62/* WDOG_IRQ_MASK Register 32bit (R/W) */
63#define U300_WDOG_IMR 0x24
64#define U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE 0x0001U
65/* WDOG_IRQ_FORCE Register 32bit (R/W) */
66#define U300_WDOG_IFR 0x28
67#define U300_WDOG_IFR_WILL_BARK_IRQ_FORCE_ENABLE 0x0001U
68
69/* Default timeout in seconds = 1 minute */
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +010070static unsigned int margin = 60;
Linus Walleij01480702009-05-06 15:35:40 +020071static resource_size_t phybase;
72static resource_size_t physize;
73static int irq;
74static void __iomem *virtbase;
Linus Walleij01480702009-05-06 15:35:40 +020075static struct device *parent;
76
77/*
78 * The watchdog block is of course always clocked, the
79 * clk_enable()/clk_disable() calls are mainly for performing reference
80 * counting higher up in the clock hierarchy.
81 */
82static struct clk *clk;
83
84/*
85 * Enabling and disabling functions.
86 */
87static void coh901327_enable(u16 timeout)
88{
89 u16 val;
Linus Walleij5973bee2009-07-21 00:40:46 +020090 unsigned long freq;
91 unsigned long delay_ns;
Linus Walleij01480702009-05-06 15:35:40 +020092
93 clk_enable(clk);
94 /* Restart timer if it is disabled */
95 val = readw(virtbase + U300_WDOG_D2R);
96 if (val == U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
97 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
98 virtbase + U300_WDOG_RR);
99 /* Acknowledge any pending interrupt so it doesn't just fire off */
100 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
101 virtbase + U300_WDOG_IER);
Linus Walleij5973bee2009-07-21 00:40:46 +0200102 /*
103 * The interrupt is cleared in the 32 kHz clock domain.
104 * Wait 3 32 kHz cycles for it to take effect
105 */
106 freq = clk_get_rate(clk);
Linus Walleij0ecc3bf2009-08-10 00:04:35 +0200107 delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */
Linus Walleij5973bee2009-07-21 00:40:46 +0200108 delay_ns = 3 * delay_ns; /* Wait 3 cycles */
109 ndelay(delay_ns);
Linus Walleij01480702009-05-06 15:35:40 +0200110 /* Enable the watchdog interrupt */
111 writew(U300_WDOG_IMR_WILL_BARK_IRQ_ENABLE, virtbase + U300_WDOG_IMR);
112 /* Activate the watchdog timer */
113 writew(timeout, virtbase + U300_WDOG_TR);
114 /* Start the watchdog timer */
115 writew(U300_WDOG_FR_FEED_RESTART_TIMER, virtbase + U300_WDOG_FR);
116 /*
117 * Extra read so that this change propagate in the watchdog.
118 */
119 (void) readw(virtbase + U300_WDOG_CR);
120 val = readw(virtbase + U300_WDOG_D2R);
121 clk_disable(clk);
122 if (val != U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
123 dev_err(parent,
124 "%s(): watchdog not enabled! D2R value %04x\n",
125 __func__, val);
126}
127
128static void coh901327_disable(void)
129{
130 u16 val;
131
132 clk_enable(clk);
133 /* Disable the watchdog interrupt if it is active */
134 writew(0x0000U, virtbase + U300_WDOG_IMR);
135 /* If the watchdog is currently enabled, attempt to disable it */
136 val = readw(virtbase + U300_WDOG_D2R);
137 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED) {
138 writew(U300_WDOG_D1R_DISABLE1_DISABLE_TIMER,
139 virtbase + U300_WDOG_D1R);
140 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
141 virtbase + U300_WDOG_D2R);
142 /* Write this twice (else problems occur) */
143 writew(U300_WDOG_D2R_DISABLE2_DISABLE_TIMER,
144 virtbase + U300_WDOG_D2R);
145 }
146 val = readw(virtbase + U300_WDOG_D2R);
147 clk_disable(clk);
148 if (val != U300_WDOG_D2R_DISABLE_STATUS_DISABLED)
149 dev_err(parent,
150 "%s(): watchdog not disabled! D2R value %04x\n",
151 __func__, val);
152}
153
Linus Walleij15b25702012-03-16 09:14:12 +0100154static int coh901327_start(struct watchdog_device *wdt_dev)
Linus Walleij01480702009-05-06 15:35:40 +0200155{
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100156 coh901327_enable(wdt_dev->timeout * 100);
Linus Walleij15b25702012-03-16 09:14:12 +0100157 return 0;
Linus Walleij01480702009-05-06 15:35:40 +0200158}
159
Linus Walleij15b25702012-03-16 09:14:12 +0100160static int coh901327_stop(struct watchdog_device *wdt_dev)
161{
162 coh901327_disable();
163 return 0;
164}
165
166static int coh901327_ping(struct watchdog_device *wdd)
Linus Walleij01480702009-05-06 15:35:40 +0200167{
168 clk_enable(clk);
169 /* Feed the watchdog */
170 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
171 virtbase + U300_WDOG_FR);
172 clk_disable(clk);
Linus Walleij15b25702012-03-16 09:14:12 +0100173 return 0;
Linus Walleij01480702009-05-06 15:35:40 +0200174}
175
Linus Walleij15b25702012-03-16 09:14:12 +0100176static int coh901327_settimeout(struct watchdog_device *wdt_dev,
177 unsigned int time)
Linus Walleij01480702009-05-06 15:35:40 +0200178{
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100179 wdt_dev->timeout = time;
Linus Walleij01480702009-05-06 15:35:40 +0200180 clk_enable(clk);
181 /* Set new timeout value */
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100182 writew(time * 100, virtbase + U300_WDOG_TR);
Linus Walleij01480702009-05-06 15:35:40 +0200183 /* Feed the dog */
184 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
185 virtbase + U300_WDOG_FR);
186 clk_disable(clk);
187 return 0;
188}
189
Linus Walleij15b25702012-03-16 09:14:12 +0100190static unsigned int coh901327_gettimeleft(struct watchdog_device *wdt_dev)
191{
192 u16 val;
193
194 clk_enable(clk);
195 /* Read repeatedly until the value is stable! */
196 val = readw(virtbase + U300_WDOG_CR);
197 while (val & U300_WDOG_CR_VALID_IND)
198 val = readw(virtbase + U300_WDOG_CR);
199 val &= U300_WDOG_CR_COUNT_VALUE_MASK;
200 clk_disable(clk);
201 if (val != 0)
202 val /= 100;
203
204 return val;
205}
206
Linus Walleij01480702009-05-06 15:35:40 +0200207/*
208 * This interrupt occurs 10 ms before the watchdog WILL bark.
209 */
210static irqreturn_t coh901327_interrupt(int irq, void *data)
211{
212 u16 val;
213
214 /*
215 * Ack IRQ? If this occurs we're FUBAR anyway, so
216 * just acknowledge, disable the interrupt and await the imminent end.
217 * If you at some point need a host of callbacks to be called
218 * when the system is about to watchdog-reset, add them here!
219 *
220 * NOTE: on future versions of this IP-block, it will be possible
221 * to prevent a watchdog reset by feeding the watchdog at this
222 * point.
223 */
224 clk_enable(clk);
225 val = readw(virtbase + U300_WDOG_IER);
226 if (val == U300_WDOG_IER_WILL_BARK_IRQ_EVENT_IND)
227 writew(U300_WDOG_IER_WILL_BARK_IRQ_ACK_ENABLE,
228 virtbase + U300_WDOG_IER);
229 writew(0x0000U, virtbase + U300_WDOG_IMR);
230 clk_disable(clk);
231 dev_crit(parent, "watchdog is barking!\n");
232 return IRQ_HANDLED;
233}
234
Linus Walleij15b25702012-03-16 09:14:12 +0100235static const struct watchdog_info coh901327_ident = {
236 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
237 .identity = DRV_NAME,
Linus Walleij01480702009-05-06 15:35:40 +0200238};
239
Linus Walleij15b25702012-03-16 09:14:12 +0100240static struct watchdog_ops coh901327_ops = {
241 .owner = THIS_MODULE,
242 .start = coh901327_start,
243 .stop = coh901327_stop,
244 .ping = coh901327_ping,
245 .set_timeout = coh901327_settimeout,
246 .get_timeleft = coh901327_gettimeleft,
247};
248
249static struct watchdog_device coh901327_wdt = {
250 .info = &coh901327_ident,
251 .ops = &coh901327_ops,
252 /*
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100253 * Max timeout is 327 since the 10ms
Linus Walleij15b25702012-03-16 09:14:12 +0100254 * timeout register is max
255 * 0x7FFF = 327670ms ~= 327s.
256 */
257 .min_timeout = 0,
258 .max_timeout = 327,
Linus Walleij01480702009-05-06 15:35:40 +0200259};
260
261static int __exit coh901327_remove(struct platform_device *pdev)
262{
Linus Walleij15b25702012-03-16 09:14:12 +0100263 watchdog_unregister_device(&coh901327_wdt);
Linus Walleij01480702009-05-06 15:35:40 +0200264 coh901327_disable();
265 free_irq(irq, pdev);
Linus Walleijc362cb52012-06-12 19:19:01 +0200266 clk_unprepare(clk);
Linus Walleij01480702009-05-06 15:35:40 +0200267 clk_put(clk);
268 iounmap(virtbase);
269 release_mem_region(phybase, physize);
270 return 0;
271}
272
Linus Walleij01480702009-05-06 15:35:40 +0200273static int __init coh901327_probe(struct platform_device *pdev)
274{
275 int ret;
276 u16 val;
277 struct resource *res;
278
279 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
280 if (!res)
281 return -ENOENT;
282
283 parent = &pdev->dev;
284 physize = resource_size(res);
285 phybase = res->start;
286
287 if (request_mem_region(phybase, physize, DRV_NAME) == NULL) {
288 ret = -EBUSY;
289 goto out;
290 }
291
292 virtbase = ioremap(phybase, physize);
293 if (!virtbase) {
294 ret = -ENOMEM;
295 goto out_no_remap;
296 }
297
298 clk = clk_get(&pdev->dev, NULL);
299 if (IS_ERR(clk)) {
300 ret = PTR_ERR(clk);
301 dev_err(&pdev->dev, "could not get clock\n");
302 goto out_no_clk;
303 }
Linus Walleijc362cb52012-06-12 19:19:01 +0200304 ret = clk_prepare_enable(clk);
Linus Walleij01480702009-05-06 15:35:40 +0200305 if (ret) {
Linus Walleijc362cb52012-06-12 19:19:01 +0200306 dev_err(&pdev->dev, "could not prepare and enable clock\n");
Linus Walleij01480702009-05-06 15:35:40 +0200307 goto out_no_clk_enable;
308 }
309
310 val = readw(virtbase + U300_WDOG_SR);
311 switch (val) {
312 case U300_WDOG_SR_STATUS_TIMED_OUT:
313 dev_info(&pdev->dev,
314 "watchdog timed out since last chip reset!\n");
Linus Walleij15b25702012-03-16 09:14:12 +0100315 coh901327_wdt.bootstatus |= WDIOF_CARDRESET;
Linus Walleij01480702009-05-06 15:35:40 +0200316 /* Status will be cleared below */
317 break;
318 case U300_WDOG_SR_STATUS_NORMAL:
319 dev_info(&pdev->dev,
320 "in normal status, no timeouts have occurred.\n");
321 break;
322 default:
323 dev_info(&pdev->dev,
324 "contains an illegal status code (%08x)\n", val);
325 break;
326 }
327
328 val = readw(virtbase + U300_WDOG_D2R);
329 switch (val) {
330 case U300_WDOG_D2R_DISABLE_STATUS_DISABLED:
331 dev_info(&pdev->dev, "currently disabled.\n");
332 break;
333 case U300_WDOG_D2R_DISABLE_STATUS_ENABLED:
334 dev_info(&pdev->dev,
335 "currently enabled! (disabling it now)\n");
336 coh901327_disable();
337 break;
338 default:
339 dev_err(&pdev->dev,
340 "contains an illegal enable/disable code (%08x)\n",
341 val);
342 break;
343 }
344
345 /* Reset the watchdog */
346 writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR);
347
348 irq = platform_get_irq(pdev, 0);
Yong Zhang86b59122011-09-07 16:10:55 +0800349 if (request_irq(irq, coh901327_interrupt, 0,
Linus Walleij01480702009-05-06 15:35:40 +0200350 DRV_NAME " Bark", pdev)) {
351 ret = -EIO;
352 goto out_no_irq;
353 }
354
355 clk_disable(clk);
356
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100357 if (margin < 1 || margin > 327)
358 margin = 60;
359 coh901327_wdt.timeout = margin;
360
Linus Walleij15b25702012-03-16 09:14:12 +0100361 ret = watchdog_register_device(&coh901327_wdt);
Linus Walleij01480702009-05-06 15:35:40 +0200362 if (ret == 0)
363 dev_info(&pdev->dev,
364 "initialized. timer margin=%d sec\n", margin);
365 else
366 goto out_no_wdog;
367
368 return 0;
369
370out_no_wdog:
371 free_irq(irq, pdev);
372out_no_irq:
Linus Walleijc362cb52012-06-12 19:19:01 +0200373 clk_disable_unprepare(clk);
Linus Walleij01480702009-05-06 15:35:40 +0200374out_no_clk_enable:
375 clk_put(clk);
376out_no_clk:
377 iounmap(virtbase);
378out_no_remap:
379 release_mem_region(phybase, SZ_4K);
380out:
381 return ret;
382}
383
384#ifdef CONFIG_PM
Linus Walleij452190c2011-10-03 10:52:58 +0200385
386static u16 wdogenablestore;
387static u16 irqmaskstore;
388
Linus Walleij01480702009-05-06 15:35:40 +0200389static int coh901327_suspend(struct platform_device *pdev, pm_message_t state)
390{
391 irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U;
392 wdogenablestore = readw(virtbase + U300_WDOG_D2R);
393 /* If watchdog is on, disable it here and now */
394 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED)
395 coh901327_disable();
396 return 0;
397}
398
399static int coh901327_resume(struct platform_device *pdev)
400{
401 /* Restore the watchdog interrupt */
402 writew(irqmaskstore, virtbase + U300_WDOG_IMR);
403 if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) {
404 /* Restart the watchdog timer */
405 writew(U300_WDOG_RR_RESTART_VALUE_RESUME,
406 virtbase + U300_WDOG_RR);
407 writew(U300_WDOG_FR_FEED_RESTART_TIMER,
408 virtbase + U300_WDOG_FR);
409 }
410 return 0;
411}
412#else
413#define coh901327_suspend NULL
414#define coh901327_resume NULL
415#endif
416
417/*
418 * Mistreating the watchdog is the only way to perform a software reset of the
419 * system on EMP platforms. So we implement this and export a symbol for it.
420 */
421void coh901327_watchdog_reset(void)
422{
423 /* Enable even if on JTAG too */
424 writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE,
425 virtbase + U300_WDOG_JOR);
426 /*
427 * Timeout = 5s, we have to wait for the watchdog reset to
428 * actually take place: the watchdog will be reloaded with the
429 * default value immediately, so we HAVE to reboot and get back
430 * into the kernel in 30s, or the device will reboot again!
431 * The boot loader will typically deactivate the watchdog, so we
432 * need time enough for the boot loader to get to the point of
433 * deactivating the watchdog before it is shut down by it.
434 *
435 * NOTE: on future versions of the watchdog, this restriction is
André Goddard Rosaaf901ca2009-11-14 13:09:05 -0200436 * gone: the watchdog will be reloaded with a default value (1 min)
Linus Walleij01480702009-05-06 15:35:40 +0200437 * instead of last value, and you can conveniently set the watchdog
438 * timeout to 10ms (value = 1) without any problems.
439 */
440 coh901327_enable(500);
441 /* Return and await doom */
442}
443
444static struct platform_driver coh901327_driver = {
445 .driver = {
446 .owner = THIS_MODULE,
447 .name = "coh901327_wdog",
448 },
449 .remove = __exit_p(coh901327_remove),
450 .suspend = coh901327_suspend,
451 .resume = coh901327_resume,
452};
453
454static int __init coh901327_init(void)
455{
456 return platform_driver_probe(&coh901327_driver, coh901327_probe);
457}
458module_init(coh901327_init);
459
460static void __exit coh901327_exit(void)
461{
462 platform_driver_unregister(&coh901327_driver);
463}
464module_exit(coh901327_exit);
465
466MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
467MODULE_DESCRIPTION("COH 901 327 Watchdog");
468
Wim Van Sebroeckdddbc6a2012-03-22 20:42:16 +0100469module_param(margin, uint, 0);
Linus Walleij01480702009-05-06 15:35:40 +0200470MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
471
472MODULE_LICENSE("GPL");
Linus Walleij15b25702012-03-16 09:14:12 +0100473MODULE_ALIAS("platform:coh901327-watchdog");