watchdog: nowayout is bool
[linux-2.6.git] / drivers / watchdog / ts72xx_wdt.c
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>
23 #include <linux/slab.h>
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 bool nowayout = WATCHDOG_NOWAYOUT;
38 module_param(nowayout, bool, 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  *      -------------------------
71  *      0x00    watchdog disabled
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
311         case WDIOC_GETSTATUS:
312         case WDIOC_GETBOOTSTATUS:
313                 return put_user(0, p);
314
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
452         /* make sure that the watchdog is disabled */
453         ts72xx_wdt_stop(wdt);
454
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
488         iounmap(wdt->feed_reg);
489         res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
490         release_mem_region(res->start, resource_size(res));
491
492         iounmap(wdt->control_reg);
493         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
494         release_mem_region(res->start, resource_size(res));
495
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
509 module_platform_driver(ts72xx_wdt_driver);
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");