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01480701 LW |
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> | |
01480701 LW |
11 | #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> | |
01480701 | 17 | #include <linux/clk.h> |
5973bee4 | 18 | #include <linux/delay.h> |
15b25701 | 19 | #include <linux/err.h> |
01480701 LW |
20 | |
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 */ | |
dddbc6a0 | 70 | static unsigned int margin = 60; |
01480701 LW |
71 | static resource_size_t phybase; |
72 | static resource_size_t physize; | |
73 | static int irq; | |
74 | static void __iomem *virtbase; | |
01480701 LW |
75 | static 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 | */ | |
82 | static struct clk *clk; | |
83 | ||
84 | /* | |
85 | * Enabling and disabling functions. | |
86 | */ | |
87 | static void coh901327_enable(u16 timeout) | |
88 | { | |
89 | u16 val; | |
5973bee4 LW |
90 | unsigned long freq; |
91 | unsigned long delay_ns; | |
01480701 LW |
92 | |
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); | |
5973bee4 LW |
102 | /* |
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); | |
0ecc3bf4 | 107 | delay_ns = DIV_ROUND_UP(1000000000, freq); /* Freq to ns and round up */ |
5973bee4 LW |
108 | delay_ns = 3 * delay_ns; /* Wait 3 cycles */ |
109 | ndelay(delay_ns); | |
01480701 LW |
110 | /* 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 | ||
128 | static 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 | ||
15b25701 | 154 | static int coh901327_start(struct watchdog_device *wdt_dev) |
01480701 | 155 | { |
dddbc6a0 | 156 | coh901327_enable(wdt_dev->timeout * 100); |
15b25701 LW |
157 | return 0; |
158 | } | |
159 | ||
160 | static int coh901327_stop(struct watchdog_device *wdt_dev) | |
161 | { | |
162 | coh901327_disable(); | |
163 | return 0; | |
01480701 LW |
164 | } |
165 | ||
15b25701 | 166 | static int coh901327_ping(struct watchdog_device *wdd) |
01480701 LW |
167 | { |
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); | |
15b25701 | 173 | return 0; |
01480701 LW |
174 | } |
175 | ||
15b25701 LW |
176 | static int coh901327_settimeout(struct watchdog_device *wdt_dev, |
177 | unsigned int time) | |
01480701 | 178 | { |
dddbc6a0 | 179 | wdt_dev->timeout = time; |
01480701 LW |
180 | clk_enable(clk); |
181 | /* Set new timeout value */ | |
dddbc6a0 | 182 | writew(time * 100, virtbase + U300_WDOG_TR); |
01480701 LW |
183 | /* 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 | ||
15b25701 LW |
190 | static 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 | ||
01480701 LW |
207 | /* |
208 | * This interrupt occurs 10 ms before the watchdog WILL bark. | |
209 | */ | |
210 | static 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 | ||
15b25701 LW |
235 | static const struct watchdog_info coh901327_ident = { |
236 | .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
237 | .identity = DRV_NAME, | |
238 | }; | |
01480701 | 239 | |
15b25701 LW |
240 | static 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, | |
01480701 LW |
247 | }; |
248 | ||
15b25701 LW |
249 | static struct watchdog_device coh901327_wdt = { |
250 | .info = &coh901327_ident, | |
251 | .ops = &coh901327_ops, | |
252 | /* | |
dddbc6a0 | 253 | * Max timeout is 327 since the 10ms |
15b25701 LW |
254 | * timeout register is max |
255 | * 0x7FFF = 327670ms ~= 327s. | |
256 | */ | |
257 | .min_timeout = 0, | |
258 | .max_timeout = 327, | |
01480701 LW |
259 | }; |
260 | ||
261 | static int __exit coh901327_remove(struct platform_device *pdev) | |
262 | { | |
15b25701 | 263 | watchdog_unregister_device(&coh901327_wdt); |
01480701 LW |
264 | coh901327_disable(); |
265 | free_irq(irq, pdev); | |
266 | clk_put(clk); | |
267 | iounmap(virtbase); | |
268 | release_mem_region(phybase, physize); | |
269 | return 0; | |
270 | } | |
271 | ||
01480701 LW |
272 | static int __init coh901327_probe(struct platform_device *pdev) |
273 | { | |
274 | int ret; | |
275 | u16 val; | |
276 | struct resource *res; | |
277 | ||
278 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
279 | if (!res) | |
280 | return -ENOENT; | |
281 | ||
282 | parent = &pdev->dev; | |
283 | physize = resource_size(res); | |
284 | phybase = res->start; | |
285 | ||
286 | if (request_mem_region(phybase, physize, DRV_NAME) == NULL) { | |
287 | ret = -EBUSY; | |
288 | goto out; | |
289 | } | |
290 | ||
291 | virtbase = ioremap(phybase, physize); | |
292 | if (!virtbase) { | |
293 | ret = -ENOMEM; | |
294 | goto out_no_remap; | |
295 | } | |
296 | ||
297 | clk = clk_get(&pdev->dev, NULL); | |
298 | if (IS_ERR(clk)) { | |
299 | ret = PTR_ERR(clk); | |
300 | dev_err(&pdev->dev, "could not get clock\n"); | |
301 | goto out_no_clk; | |
302 | } | |
303 | ret = clk_enable(clk); | |
304 | if (ret) { | |
305 | dev_err(&pdev->dev, "could not enable clock\n"); | |
306 | goto out_no_clk_enable; | |
307 | } | |
308 | ||
309 | val = readw(virtbase + U300_WDOG_SR); | |
310 | switch (val) { | |
311 | case U300_WDOG_SR_STATUS_TIMED_OUT: | |
312 | dev_info(&pdev->dev, | |
313 | "watchdog timed out since last chip reset!\n"); | |
15b25701 | 314 | coh901327_wdt.bootstatus |= WDIOF_CARDRESET; |
01480701 LW |
315 | /* Status will be cleared below */ |
316 | break; | |
317 | case U300_WDOG_SR_STATUS_NORMAL: | |
318 | dev_info(&pdev->dev, | |
319 | "in normal status, no timeouts have occurred.\n"); | |
320 | break; | |
321 | default: | |
322 | dev_info(&pdev->dev, | |
323 | "contains an illegal status code (%08x)\n", val); | |
324 | break; | |
325 | } | |
326 | ||
327 | val = readw(virtbase + U300_WDOG_D2R); | |
328 | switch (val) { | |
329 | case U300_WDOG_D2R_DISABLE_STATUS_DISABLED: | |
330 | dev_info(&pdev->dev, "currently disabled.\n"); | |
331 | break; | |
332 | case U300_WDOG_D2R_DISABLE_STATUS_ENABLED: | |
333 | dev_info(&pdev->dev, | |
334 | "currently enabled! (disabling it now)\n"); | |
335 | coh901327_disable(); | |
336 | break; | |
337 | default: | |
338 | dev_err(&pdev->dev, | |
339 | "contains an illegal enable/disable code (%08x)\n", | |
340 | val); | |
341 | break; | |
342 | } | |
343 | ||
344 | /* Reset the watchdog */ | |
345 | writew(U300_WDOG_SR_RESET_STATUS_RESET, virtbase + U300_WDOG_SR); | |
346 | ||
347 | irq = platform_get_irq(pdev, 0); | |
86b59128 | 348 | if (request_irq(irq, coh901327_interrupt, 0, |
01480701 LW |
349 | DRV_NAME " Bark", pdev)) { |
350 | ret = -EIO; | |
351 | goto out_no_irq; | |
352 | } | |
353 | ||
354 | clk_disable(clk); | |
355 | ||
dddbc6a0 WVS |
356 | if (margin < 1 || margin > 327) |
357 | margin = 60; | |
358 | coh901327_wdt.timeout = margin; | |
359 | ||
15b25701 | 360 | ret = watchdog_register_device(&coh901327_wdt); |
01480701 LW |
361 | if (ret == 0) |
362 | dev_info(&pdev->dev, | |
363 | "initialized. timer margin=%d sec\n", margin); | |
364 | else | |
365 | goto out_no_wdog; | |
366 | ||
367 | return 0; | |
368 | ||
369 | out_no_wdog: | |
370 | free_irq(irq, pdev); | |
371 | out_no_irq: | |
372 | clk_disable(clk); | |
373 | out_no_clk_enable: | |
374 | clk_put(clk); | |
375 | out_no_clk: | |
376 | iounmap(virtbase); | |
377 | out_no_remap: | |
378 | release_mem_region(phybase, SZ_4K); | |
379 | out: | |
380 | return ret; | |
381 | } | |
382 | ||
383 | #ifdef CONFIG_PM | |
452190cb LW |
384 | |
385 | static u16 wdogenablestore; | |
386 | static u16 irqmaskstore; | |
387 | ||
01480701 LW |
388 | static int coh901327_suspend(struct platform_device *pdev, pm_message_t state) |
389 | { | |
390 | irqmaskstore = readw(virtbase + U300_WDOG_IMR) & 0x0001U; | |
391 | wdogenablestore = readw(virtbase + U300_WDOG_D2R); | |
392 | /* If watchdog is on, disable it here and now */ | |
393 | if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) | |
394 | coh901327_disable(); | |
395 | return 0; | |
396 | } | |
397 | ||
398 | static int coh901327_resume(struct platform_device *pdev) | |
399 | { | |
400 | /* Restore the watchdog interrupt */ | |
401 | writew(irqmaskstore, virtbase + U300_WDOG_IMR); | |
402 | if (wdogenablestore == U300_WDOG_D2R_DISABLE_STATUS_ENABLED) { | |
403 | /* Restart the watchdog timer */ | |
404 | writew(U300_WDOG_RR_RESTART_VALUE_RESUME, | |
405 | virtbase + U300_WDOG_RR); | |
406 | writew(U300_WDOG_FR_FEED_RESTART_TIMER, | |
407 | virtbase + U300_WDOG_FR); | |
408 | } | |
409 | return 0; | |
410 | } | |
411 | #else | |
412 | #define coh901327_suspend NULL | |
413 | #define coh901327_resume NULL | |
414 | #endif | |
415 | ||
416 | /* | |
417 | * Mistreating the watchdog is the only way to perform a software reset of the | |
418 | * system on EMP platforms. So we implement this and export a symbol for it. | |
419 | */ | |
420 | void coh901327_watchdog_reset(void) | |
421 | { | |
422 | /* Enable even if on JTAG too */ | |
423 | writew(U300_WDOG_JOR_JTAG_WATCHDOG_ENABLE, | |
424 | virtbase + U300_WDOG_JOR); | |
425 | /* | |
426 | * Timeout = 5s, we have to wait for the watchdog reset to | |
427 | * actually take place: the watchdog will be reloaded with the | |
428 | * default value immediately, so we HAVE to reboot and get back | |
429 | * into the kernel in 30s, or the device will reboot again! | |
430 | * The boot loader will typically deactivate the watchdog, so we | |
431 | * need time enough for the boot loader to get to the point of | |
432 | * deactivating the watchdog before it is shut down by it. | |
433 | * | |
434 | * NOTE: on future versions of the watchdog, this restriction is | |
af901ca1 | 435 | * gone: the watchdog will be reloaded with a default value (1 min) |
01480701 LW |
436 | * instead of last value, and you can conveniently set the watchdog |
437 | * timeout to 10ms (value = 1) without any problems. | |
438 | */ | |
439 | coh901327_enable(500); | |
440 | /* Return and await doom */ | |
441 | } | |
442 | ||
443 | static struct platform_driver coh901327_driver = { | |
444 | .driver = { | |
445 | .owner = THIS_MODULE, | |
446 | .name = "coh901327_wdog", | |
447 | }, | |
448 | .remove = __exit_p(coh901327_remove), | |
449 | .suspend = coh901327_suspend, | |
450 | .resume = coh901327_resume, | |
451 | }; | |
452 | ||
453 | static int __init coh901327_init(void) | |
454 | { | |
455 | return platform_driver_probe(&coh901327_driver, coh901327_probe); | |
456 | } | |
457 | module_init(coh901327_init); | |
458 | ||
459 | static void __exit coh901327_exit(void) | |
460 | { | |
461 | platform_driver_unregister(&coh901327_driver); | |
462 | } | |
463 | module_exit(coh901327_exit); | |
464 | ||
465 | MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>"); | |
466 | MODULE_DESCRIPTION("COH 901 327 Watchdog"); | |
467 | ||
dddbc6a0 | 468 | module_param(margin, uint, 0); |
01480701 LW |
469 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); |
470 | ||
471 | MODULE_LICENSE("GPL"); | |
15b25701 | 472 | MODULE_ALIAS("platform:coh901327-watchdog"); |