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