Commit | Line | Data |
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c90bf2aa MW |
1 | /* |
2 | * Watchdog driver for Technologic Systems TS-72xx based SBCs | |
3 | * (TS-7200, TS-7250 and TS-7260). These boards have external | |
4 | * glue logic CPLD chip, which includes programmable watchdog | |
5 | * timer. | |
6 | * | |
7 | * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi> | |
8 | * | |
9 | * This driver is based on ep93xx_wdt and wm831x_wdt drivers. | |
10 | * | |
11 | * This file is licensed under the terms of the GNU General Public | |
12 | * License version 2. This program is licensed "as is" without any | |
13 | * warranty of any kind, whether express or implied. | |
14 | */ | |
15 | ||
16 | #include <linux/fs.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleparam.h> | |
20 | #include <linux/miscdevice.h> | |
21 | #include <linux/mutex.h> | |
22 | #include <linux/platform_device.h> | |
5a0e3ad6 | 23 | #include <linux/slab.h> |
c90bf2aa MW |
24 | #include <linux/watchdog.h> |
25 | #include <linux/uaccess.h> | |
26 | ||
27 | #define TS72XX_WDT_FEED_VAL 0x05 | |
28 | #define TS72XX_WDT_DEFAULT_TIMEOUT 8 | |
29 | ||
30 | static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT; | |
31 | module_param(timeout, int, 0); | |
32 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. " | |
33 | "(1 <= timeout <= 8, default=" | |
34 | __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT) | |
35 | ")"); | |
36 | ||
37 | static int nowayout = WATCHDOG_NOWAYOUT; | |
38 | module_param(nowayout, int, 0); | |
39 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); | |
40 | ||
41 | /** | |
42 | * struct ts72xx_wdt - watchdog control structure | |
43 | * @lock: lock that protects this structure | |
44 | * @regval: watchdog timeout value suitable for control register | |
45 | * @flags: flags controlling watchdog device state | |
46 | * @control_reg: watchdog control register | |
47 | * @feed_reg: watchdog feed register | |
48 | * @pdev: back pointer to platform dev | |
49 | */ | |
50 | struct ts72xx_wdt { | |
51 | struct mutex lock; | |
52 | int regval; | |
53 | ||
54 | #define TS72XX_WDT_BUSY_FLAG 1 | |
55 | #define TS72XX_WDT_EXPECT_CLOSE_FLAG 2 | |
56 | int flags; | |
57 | ||
58 | void __iomem *control_reg; | |
59 | void __iomem *feed_reg; | |
60 | ||
61 | struct platform_device *pdev; | |
62 | }; | |
63 | ||
64 | struct platform_device *ts72xx_wdt_pdev; | |
65 | ||
66 | /* | |
67 | * TS-72xx Watchdog supports following timeouts (value written | |
68 | * to control register): | |
69 | * value description | |
70 | * ------------------------- | |
5f3b2756 | 71 | * 0x00 watchdog disabled |
c90bf2aa MW |
72 | * 0x01 250ms |
73 | * 0x02 500ms | |
74 | * 0x03 1s | |
75 | * 0x04 reserved | |
76 | * 0x05 2s | |
77 | * 0x06 4s | |
78 | * 0x07 8s | |
79 | * | |
80 | * Timeouts below 1s are not very usable so we don't | |
81 | * allow them at all. | |
82 | * | |
83 | * We provide two functions that convert between these: | |
84 | * timeout_to_regval() and regval_to_timeout(). | |
85 | */ | |
86 | static const struct { | |
87 | int timeout; | |
88 | int regval; | |
89 | } ts72xx_wdt_map[] = { | |
90 | { 1, 3 }, | |
91 | { 2, 5 }, | |
92 | { 4, 6 }, | |
93 | { 8, 7 }, | |
94 | }; | |
95 | ||
96 | /** | |
97 | * timeout_to_regval() - converts given timeout to control register value | |
98 | * @new_timeout: timeout in seconds to be converted | |
99 | * | |
100 | * Function converts given @new_timeout into valid value that can | |
101 | * be programmed into watchdog control register. When conversion is | |
102 | * not possible, function returns %-EINVAL. | |
103 | */ | |
104 | static int timeout_to_regval(int new_timeout) | |
105 | { | |
106 | int i; | |
107 | ||
108 | /* first limit it to 1 - 8 seconds */ | |
109 | new_timeout = clamp_val(new_timeout, 1, 8); | |
110 | ||
111 | for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) { | |
112 | if (ts72xx_wdt_map[i].timeout >= new_timeout) | |
113 | return ts72xx_wdt_map[i].regval; | |
114 | } | |
115 | ||
116 | return -EINVAL; | |
117 | } | |
118 | ||
119 | /** | |
120 | * regval_to_timeout() - converts control register value to timeout | |
121 | * @regval: control register value to be converted | |
122 | * | |
123 | * Function converts given @regval to timeout in seconds (1, 2, 4 or 8). | |
124 | * If @regval cannot be converted, function returns %-EINVAL. | |
125 | */ | |
126 | static int regval_to_timeout(int regval) | |
127 | { | |
128 | int i; | |
129 | ||
130 | for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) { | |
131 | if (ts72xx_wdt_map[i].regval == regval) | |
132 | return ts72xx_wdt_map[i].timeout; | |
133 | } | |
134 | ||
135 | return -EINVAL; | |
136 | } | |
137 | ||
138 | /** | |
139 | * ts72xx_wdt_kick() - kick the watchdog | |
140 | * @wdt: watchdog to be kicked | |
141 | * | |
142 | * Called with @wdt->lock held. | |
143 | */ | |
144 | static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt) | |
145 | { | |
146 | __raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg); | |
147 | } | |
148 | ||
149 | /** | |
150 | * ts72xx_wdt_start() - starts the watchdog timer | |
151 | * @wdt: watchdog to be started | |
152 | * | |
153 | * This function programs timeout to watchdog timer | |
154 | * and starts it. | |
155 | * | |
156 | * Called with @wdt->lock held. | |
157 | */ | |
158 | static void ts72xx_wdt_start(struct ts72xx_wdt *wdt) | |
159 | { | |
160 | /* | |
161 | * To program the wdt, it first must be "fed" and | |
162 | * only after that (within 30 usecs) the configuration | |
163 | * can be changed. | |
164 | */ | |
165 | ts72xx_wdt_kick(wdt); | |
166 | __raw_writeb((u8)wdt->regval, wdt->control_reg); | |
167 | } | |
168 | ||
169 | /** | |
170 | * ts72xx_wdt_stop() - stops the watchdog timer | |
171 | * @wdt: watchdog to be stopped | |
172 | * | |
173 | * Called with @wdt->lock held. | |
174 | */ | |
175 | static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt) | |
176 | { | |
177 | ts72xx_wdt_kick(wdt); | |
178 | __raw_writeb(0, wdt->control_reg); | |
179 | } | |
180 | ||
181 | static int ts72xx_wdt_open(struct inode *inode, struct file *file) | |
182 | { | |
183 | struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev); | |
184 | int regval; | |
185 | ||
186 | /* | |
187 | * Try to convert default timeout to valid register | |
188 | * value first. | |
189 | */ | |
190 | regval = timeout_to_regval(timeout); | |
191 | if (regval < 0) { | |
192 | dev_err(&wdt->pdev->dev, | |
193 | "failed to convert timeout (%d) to register value\n", | |
194 | timeout); | |
195 | return -EINVAL; | |
196 | } | |
197 | ||
198 | if (mutex_lock_interruptible(&wdt->lock)) | |
199 | return -ERESTARTSYS; | |
200 | ||
201 | if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) { | |
202 | mutex_unlock(&wdt->lock); | |
203 | return -EBUSY; | |
204 | } | |
205 | ||
206 | wdt->flags = TS72XX_WDT_BUSY_FLAG; | |
207 | wdt->regval = regval; | |
208 | file->private_data = wdt; | |
209 | ||
210 | ts72xx_wdt_start(wdt); | |
211 | ||
212 | mutex_unlock(&wdt->lock); | |
213 | return nonseekable_open(inode, file); | |
214 | } | |
215 | ||
216 | static int ts72xx_wdt_release(struct inode *inode, struct file *file) | |
217 | { | |
218 | struct ts72xx_wdt *wdt = file->private_data; | |
219 | ||
220 | if (mutex_lock_interruptible(&wdt->lock)) | |
221 | return -ERESTARTSYS; | |
222 | ||
223 | if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) { | |
224 | ts72xx_wdt_stop(wdt); | |
225 | } else { | |
226 | dev_warn(&wdt->pdev->dev, | |
227 | "TS-72XX WDT device closed unexpectly. " | |
228 | "Watchdog timer will not stop!\n"); | |
229 | /* | |
230 | * Kick it one more time, to give userland some time | |
231 | * to recover (for example, respawning the kicker | |
232 | * daemon). | |
233 | */ | |
234 | ts72xx_wdt_kick(wdt); | |
235 | } | |
236 | ||
237 | wdt->flags = 0; | |
238 | ||
239 | mutex_unlock(&wdt->lock); | |
240 | return 0; | |
241 | } | |
242 | ||
243 | static ssize_t ts72xx_wdt_write(struct file *file, | |
244 | const char __user *data, | |
245 | size_t len, | |
246 | loff_t *ppos) | |
247 | { | |
248 | struct ts72xx_wdt *wdt = file->private_data; | |
249 | ||
250 | if (!len) | |
251 | return 0; | |
252 | ||
253 | if (mutex_lock_interruptible(&wdt->lock)) | |
254 | return -ERESTARTSYS; | |
255 | ||
256 | ts72xx_wdt_kick(wdt); | |
257 | ||
258 | /* | |
259 | * Support for magic character closing. User process | |
260 | * writes 'V' into the device, just before it is closed. | |
261 | * This means that we know that the wdt timer can be | |
262 | * stopped after user closes the device. | |
263 | */ | |
264 | if (!nowayout) { | |
265 | int i; | |
266 | ||
267 | for (i = 0; i < len; i++) { | |
268 | char c; | |
269 | ||
270 | /* In case it was set long ago */ | |
271 | wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG; | |
272 | ||
273 | if (get_user(c, data + i)) { | |
274 | mutex_unlock(&wdt->lock); | |
275 | return -EFAULT; | |
276 | } | |
277 | if (c == 'V') { | |
278 | wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG; | |
279 | break; | |
280 | } | |
281 | } | |
282 | } | |
283 | ||
284 | mutex_unlock(&wdt->lock); | |
285 | return len; | |
286 | } | |
287 | ||
288 | static const struct watchdog_info winfo = { | |
289 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | | |
290 | WDIOF_MAGICCLOSE, | |
291 | .firmware_version = 1, | |
292 | .identity = "TS-72XX WDT", | |
293 | }; | |
294 | ||
295 | static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd, | |
296 | unsigned long arg) | |
297 | { | |
298 | struct ts72xx_wdt *wdt = file->private_data; | |
299 | void __user *argp = (void __user *)arg; | |
300 | int __user *p = (int __user *)argp; | |
301 | int error = 0; | |
302 | ||
303 | if (mutex_lock_interruptible(&wdt->lock)) | |
304 | return -ERESTARTSYS; | |
305 | ||
306 | switch (cmd) { | |
307 | case WDIOC_GETSUPPORT: | |
308 | error = copy_to_user(argp, &winfo, sizeof(winfo)); | |
309 | break; | |
310 | ||
f538ed9e WVS |
311 | case WDIOC_GETSTATUS: |
312 | case WDIOC_GETBOOTSTATUS: | |
313 | return put_user(0, p); | |
314 | ||
c90bf2aa MW |
315 | case WDIOC_KEEPALIVE: |
316 | ts72xx_wdt_kick(wdt); | |
317 | break; | |
318 | ||
319 | case WDIOC_SETOPTIONS: { | |
320 | int options; | |
321 | ||
322 | if (get_user(options, p)) { | |
323 | error = -EFAULT; | |
324 | break; | |
325 | } | |
326 | ||
327 | error = -EINVAL; | |
328 | ||
329 | if ((options & WDIOS_DISABLECARD) != 0) { | |
330 | ts72xx_wdt_stop(wdt); | |
331 | error = 0; | |
332 | } | |
333 | if ((options & WDIOS_ENABLECARD) != 0) { | |
334 | ts72xx_wdt_start(wdt); | |
335 | error = 0; | |
336 | } | |
337 | ||
338 | break; | |
339 | } | |
340 | ||
341 | case WDIOC_SETTIMEOUT: { | |
342 | int new_timeout; | |
343 | ||
344 | if (get_user(new_timeout, p)) { | |
345 | error = -EFAULT; | |
346 | } else { | |
347 | int regval; | |
348 | ||
349 | regval = timeout_to_regval(new_timeout); | |
350 | if (regval < 0) { | |
351 | error = -EINVAL; | |
352 | } else { | |
353 | ts72xx_wdt_stop(wdt); | |
354 | wdt->regval = regval; | |
355 | ts72xx_wdt_start(wdt); | |
356 | } | |
357 | } | |
358 | if (error) | |
359 | break; | |
360 | ||
361 | /*FALLTHROUGH*/ | |
362 | } | |
363 | ||
364 | case WDIOC_GETTIMEOUT: | |
365 | if (put_user(regval_to_timeout(wdt->regval), p)) | |
366 | error = -EFAULT; | |
367 | break; | |
368 | ||
369 | default: | |
370 | error = -ENOTTY; | |
371 | break; | |
372 | } | |
373 | ||
374 | mutex_unlock(&wdt->lock); | |
375 | return error; | |
376 | } | |
377 | ||
378 | static const struct file_operations ts72xx_wdt_fops = { | |
379 | .owner = THIS_MODULE, | |
380 | .llseek = no_llseek, | |
381 | .open = ts72xx_wdt_open, | |
382 | .release = ts72xx_wdt_release, | |
383 | .write = ts72xx_wdt_write, | |
384 | .unlocked_ioctl = ts72xx_wdt_ioctl, | |
385 | }; | |
386 | ||
387 | static struct miscdevice ts72xx_wdt_miscdev = { | |
388 | .minor = WATCHDOG_MINOR, | |
389 | .name = "watchdog", | |
390 | .fops = &ts72xx_wdt_fops, | |
391 | }; | |
392 | ||
393 | static __devinit int ts72xx_wdt_probe(struct platform_device *pdev) | |
394 | { | |
395 | struct ts72xx_wdt *wdt; | |
396 | struct resource *r1, *r2; | |
397 | int error = 0; | |
398 | ||
399 | wdt = kzalloc(sizeof(struct ts72xx_wdt), GFP_KERNEL); | |
400 | if (!wdt) { | |
401 | dev_err(&pdev->dev, "failed to allocate memory\n"); | |
402 | return -ENOMEM; | |
403 | } | |
404 | ||
405 | r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
406 | if (!r1) { | |
407 | dev_err(&pdev->dev, "failed to get memory resource\n"); | |
408 | error = -ENODEV; | |
409 | goto fail; | |
410 | } | |
411 | ||
412 | r1 = request_mem_region(r1->start, resource_size(r1), pdev->name); | |
413 | if (!r1) { | |
414 | dev_err(&pdev->dev, "cannot request memory region\n"); | |
415 | error = -EBUSY; | |
416 | goto fail; | |
417 | } | |
418 | ||
419 | wdt->control_reg = ioremap(r1->start, resource_size(r1)); | |
420 | if (!wdt->control_reg) { | |
421 | dev_err(&pdev->dev, "failed to map memory\n"); | |
422 | error = -ENODEV; | |
423 | goto fail_free_control; | |
424 | } | |
425 | ||
426 | r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1); | |
427 | if (!r2) { | |
428 | dev_err(&pdev->dev, "failed to get memory resource\n"); | |
429 | error = -ENODEV; | |
430 | goto fail_unmap_control; | |
431 | } | |
432 | ||
433 | r2 = request_mem_region(r2->start, resource_size(r2), pdev->name); | |
434 | if (!r2) { | |
435 | dev_err(&pdev->dev, "cannot request memory region\n"); | |
436 | error = -EBUSY; | |
437 | goto fail_unmap_control; | |
438 | } | |
439 | ||
440 | wdt->feed_reg = ioremap(r2->start, resource_size(r2)); | |
441 | if (!wdt->feed_reg) { | |
442 | dev_err(&pdev->dev, "failed to map memory\n"); | |
443 | error = -ENODEV; | |
444 | goto fail_free_feed; | |
445 | } | |
446 | ||
447 | platform_set_drvdata(pdev, wdt); | |
448 | ts72xx_wdt_pdev = pdev; | |
449 | wdt->pdev = pdev; | |
450 | mutex_init(&wdt->lock); | |
451 | ||
0e901bed MW |
452 | /* make sure that the watchdog is disabled */ |
453 | ts72xx_wdt_stop(wdt); | |
454 | ||
c90bf2aa MW |
455 | error = misc_register(&ts72xx_wdt_miscdev); |
456 | if (error) { | |
457 | dev_err(&pdev->dev, "failed to register miscdev\n"); | |
458 | goto fail_unmap_feed; | |
459 | } | |
460 | ||
461 | dev_info(&pdev->dev, "TS-72xx Watchdog driver\n"); | |
462 | ||
463 | return 0; | |
464 | ||
465 | fail_unmap_feed: | |
466 | platform_set_drvdata(pdev, NULL); | |
467 | iounmap(wdt->feed_reg); | |
468 | fail_free_feed: | |
469 | release_mem_region(r2->start, resource_size(r2)); | |
470 | fail_unmap_control: | |
471 | iounmap(wdt->control_reg); | |
472 | fail_free_control: | |
473 | release_mem_region(r1->start, resource_size(r1)); | |
474 | fail: | |
475 | kfree(wdt); | |
476 | return error; | |
477 | } | |
478 | ||
479 | static __devexit int ts72xx_wdt_remove(struct platform_device *pdev) | |
480 | { | |
481 | struct ts72xx_wdt *wdt = platform_get_drvdata(pdev); | |
482 | struct resource *res; | |
483 | int error; | |
484 | ||
485 | error = misc_deregister(&ts72xx_wdt_miscdev); | |
486 | platform_set_drvdata(pdev, NULL); | |
487 | ||
c90bf2aa MW |
488 | iounmap(wdt->feed_reg); |
489 | res = platform_get_resource(pdev, IORESOURCE_MEM, 1); | |
490 | release_mem_region(res->start, resource_size(res)); | |
491 | ||
f538ed9e WVS |
492 | iounmap(wdt->control_reg); |
493 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
494 | release_mem_region(res->start, resource_size(res)); | |
495 | ||
c90bf2aa MW |
496 | kfree(wdt); |
497 | return error; | |
498 | } | |
499 | ||
500 | static struct platform_driver ts72xx_wdt_driver = { | |
501 | .probe = ts72xx_wdt_probe, | |
502 | .remove = __devexit_p(ts72xx_wdt_remove), | |
503 | .driver = { | |
504 | .name = "ts72xx-wdt", | |
505 | .owner = THIS_MODULE, | |
506 | }, | |
507 | }; | |
508 | ||
b8ec6118 | 509 | module_platform_driver(ts72xx_wdt_driver); |
c90bf2aa MW |
510 | |
511 | MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>"); | |
512 | MODULE_DESCRIPTION("TS-72xx SBC Watchdog"); | |
513 | MODULE_LICENSE("GPL"); | |
514 | MODULE_ALIAS("platform:ts72xx-wdt"); |