summaryrefslogtreecommitdiffstats
path: root/drivers/char/watchdog/w83977f_wdt.c
blob: 2c8d5d8bd4e85303750274d1e9b2907b66c0bdad (plain)
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
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
/*
 *	W83977F Watchdog Timer Driver for Winbond W83977F I/O Chip
 *
 *	(c) Copyright 2005  Jose Goncalves <jose.goncalves@inov.pt>
 *
 *      Based on w83877f_wdt.c by Scott Jennings,
 *           and wdt977.c by Woody Suwalski
 *
 *			-----------------------
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 *
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/watchdog.h>
#include <linux/notifier.h>
#include <linux/reboot.h>

#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>

#define WATCHDOG_VERSION  "1.00"
#define WATCHDOG_NAME     "W83977F WDT"
#define PFX WATCHDOG_NAME ": "
#define DRIVER_VERSION    WATCHDOG_NAME " driver, v" WATCHDOG_VERSION "\n"

#define IO_INDEX_PORT     0x3F0
#define IO_DATA_PORT      (IO_INDEX_PORT+1)

#define UNLOCK_DATA       0x87
#define LOCK_DATA         0xAA
#define DEVICE_REGISTER   0x07

#define	DEFAULT_TIMEOUT   45		/* default timeout in seconds */

static	int timeout = DEFAULT_TIMEOUT;
static	int timeoutW;			/* timeout in watchdog counter units */
static	unsigned long timer_alive;
static	int testmode;
static	char expect_close;
static	spinlock_t spinlock;

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,"Watchdog timeout in seconds (15..7635), default=" __MODULE_STRING(DEFAULT_TIMEOUT) ")");
module_param(testmode, int, 0);
MODULE_PARM_DESC(testmode,"Watchdog testmode (1 = no reboot), default=0");

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");

/*
 * Start the watchdog
 */

static int wdt_start(void)
{
	unsigned long flags;

	spin_lock_irqsave(&spinlock, flags);

	/* Unlock the SuperIO chip */
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);

	/*
	 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
	 * F2 has the timeout in watchdog counter units.
	 * F3 is set to enable watchdog LED blink at timeout.
	 * F4 is used to just clear the TIMEOUT'ed state (bit 0).
	 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);
	outb_p(0xF2,IO_INDEX_PORT);
	outb_p(timeoutW,IO_DATA_PORT);
	outb_p(0xF3,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);
	outb_p(0xF4,IO_INDEX_PORT);
	outb_p(0x00,IO_DATA_PORT);

	/* Set device Aux2 active */
	outb_p(0x30,IO_INDEX_PORT);
	outb_p(0x01,IO_DATA_PORT);

	/* 
	 * Select device Aux1 (dev=7) to set GP16 as the watchdog output
	 * (in reg E6) and GP13 as the watchdog LED output (in reg E3).
	 * Map GP16 at pin 119.
	 * In test mode watch the bit 0 on F4 to indicate "triggered" or
	 * check watchdog LED on SBC.
	 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x07,IO_DATA_PORT);
	if (!testmode)
	{
		unsigned pin_map;

		outb_p(0xE6,IO_INDEX_PORT);
		outb_p(0x0A,IO_DATA_PORT);
		outb_p(0x2C,IO_INDEX_PORT);
		pin_map = inb_p(IO_DATA_PORT);
		pin_map |= 0x10;
		pin_map &= ~(0x20);
		outb_p(0x2C,IO_INDEX_PORT);
		outb_p(pin_map,IO_DATA_PORT);
	}
	outb_p(0xE3,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);

	/* Set device Aux1 active */
	outb_p(0x30,IO_INDEX_PORT);
	outb_p(0x01,IO_DATA_PORT);

	/* Lock the SuperIO chip */
	outb_p(LOCK_DATA,IO_INDEX_PORT);

	spin_unlock_irqrestore(&spinlock, flags);

	printk(KERN_INFO PFX "activated.\n");

	return 0;
}

/*
 * Stop the watchdog
 */

static int wdt_stop(void)
{
	unsigned long flags;

	spin_lock_irqsave(&spinlock, flags);

	/* Unlock the SuperIO chip */
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);

	/* 
	 * Select device Aux2 (device=8) to set watchdog regs F2, F3 and F4.
	 * F2 is reset to its default value (watchdog timer disabled).
	 * F3 is reset to its default state.
	 * F4 clears the TIMEOUT'ed state (bit 0) - back to default.
	 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);
	outb_p(0xF2,IO_INDEX_PORT);
	outb_p(0xFF,IO_DATA_PORT);
	outb_p(0xF3,IO_INDEX_PORT);
	outb_p(0x00,IO_DATA_PORT);
	outb_p(0xF4,IO_INDEX_PORT);
	outb_p(0x00,IO_DATA_PORT);
	outb_p(0xF2,IO_INDEX_PORT);
	outb_p(0x00,IO_DATA_PORT);

	/*
	 * Select device Aux1 (dev=7) to set GP16 (in reg E6) and 
	 * Gp13 (in reg E3) as inputs.
	 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x07,IO_DATA_PORT);
	if (!testmode)
	{
		outb_p(0xE6,IO_INDEX_PORT);
		outb_p(0x01,IO_DATA_PORT);
	}
	outb_p(0xE3,IO_INDEX_PORT);
	outb_p(0x01,IO_DATA_PORT);

	/* Lock the SuperIO chip */
	outb_p(LOCK_DATA,IO_INDEX_PORT);

	spin_unlock_irqrestore(&spinlock, flags);

	printk(KERN_INFO PFX "shutdown.\n");

	return 0;
}

/*
 * Send a keepalive ping to the watchdog
 * This is done by simply re-writing the timeout to reg. 0xF2
 */

static int wdt_keepalive(void)
{
	unsigned long flags;

	spin_lock_irqsave(&spinlock, flags);

	/* Unlock the SuperIO chip */
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);

	/* Select device Aux2 (device=8) to kick watchdog reg F2 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);
	outb_p(0xF2,IO_INDEX_PORT);
	outb_p(timeoutW,IO_DATA_PORT);

	/* Lock the SuperIO chip */
	outb_p(LOCK_DATA,IO_INDEX_PORT);

	spin_unlock_irqrestore(&spinlock, flags);

	return 0;
}

/*
 * Set the watchdog timeout value
 */

static int wdt_set_timeout(int t)
{
	int tmrval;

	/*
	 * Convert seconds to watchdog counter time units, rounding up.
	 * On PCM-5335 watchdog units are 30 seconds/step with 15 sec startup 
	 * value. This information is supplied in the PCM-5335 manual and was
	 * checked by me on a real board. This is a bit strange because W83977f
	 * datasheet says counter unit is in minutes!
	 */
	if (t < 15)
		return -EINVAL;

	tmrval = ((t + 15) + 29) / 30;

	if (tmrval > 255)
		return -EINVAL;

	/*
	 * timeout is the timeout in seconds, 
	 * timeoutW is the timeout in watchdog counter units.
	 */
	timeoutW = tmrval;
	timeout = (timeoutW * 30) - 15;
	return 0;
}

/*
 * Get the watchdog status
 */

static int wdt_get_status(int *status)
{
	int new_status;
	unsigned long flags;

	spin_lock_irqsave(&spinlock, flags);

	/* Unlock the SuperIO chip */
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);
	outb_p(UNLOCK_DATA,IO_INDEX_PORT);

	/* Select device Aux2 (device=8) to read watchdog reg F4 */
	outb_p(DEVICE_REGISTER,IO_INDEX_PORT);
	outb_p(0x08,IO_DATA_PORT);
	outb_p(0xF4,IO_INDEX_PORT);
	new_status = inb_p(IO_DATA_PORT);

	/* Lock the SuperIO chip */
	outb_p(LOCK_DATA,IO_INDEX_PORT);

	spin_unlock_irqrestore(&spinlock, flags);

	*status = 0;
	if (new_status & 1)
		*status |= WDIOF_CARDRESET;

	return 0;
}


/*
 *	/dev/watchdog handling
 */

static int wdt_open(struct inode *inode, struct file *file)
{
	/* If the watchdog is alive we don't need to start it again */
	if( test_and_set_bit(0, &timer_alive) )
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	wdt_start();
	return nonseekable_open(inode, file);
}

static int wdt_release(struct inode *inode, struct file *file)
{
	/*
	 * Shut off the timer.
	 * Lock it in if it's a module and we set nowayout
	 */
	if (expect_close == 42)
	{
		wdt_stop();
		clear_bit(0, &timer_alive);
	} else {
		wdt_keepalive();
		printk(KERN_CRIT PFX "unexpected close, not stopping watchdog!\n");
	}
	expect_close = 0;
	return 0;
}

/*
 *      wdt_write:
 *      @file: file handle to the watchdog
 *      @buf: buffer to write (unused as data does not matter here
 *      @count: count of bytes
 *      @ppos: pointer to the position to write. No seeks allowed
 *
 *      A write to a watchdog device is defined as a keepalive signal. Any
 *      write of data will do, as we we don't define content meaning.
 */

static ssize_t wdt_write(struct file *file, const char __user *buf,
			    size_t count, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if(count)
	{
		if (!nowayout)
		{
			size_t ofs;

			/* note: just in case someone wrote the magic character long ago */
			expect_close = 0;

			/* scan to see whether or not we got the magic character */
			for(ofs = 0; ofs != count; ofs++)
			{
				char c;
				if (get_user(c, buf + ofs))
					return -EFAULT;
				if (c == 'V') {
					expect_close = 42;
				}
			}
		}

		/* someone wrote to us, we should restart timer */
		wdt_keepalive();
	}
	return count;
}

/*
 *      wdt_ioctl:
 *      @inode: inode of the device
 *      @file: file handle to the device
 *      @cmd: watchdog command
 *      @arg: argument pointer
 *
 *      The watchdog API defines a common set of functions for all watchdogs
 *      according to their available features.
 */

static struct watchdog_info ident = {
	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
	.firmware_version =	1,
	.identity = WATCHDOG_NAME,
};

static int wdt_ioctl(struct inode *inode, struct file *file,
	unsigned int cmd, unsigned long arg)
{
	int status;
	int new_options, retval = -EINVAL;
	int new_timeout;
	union {
		struct watchdog_info __user *ident;
		int __user *i;
	} uarg;

	uarg.i = (int __user *)arg;

	switch(cmd)
	{
	default:
		return -ENOTTY;

	case WDIOC_GETSUPPORT:
		return copy_to_user(uarg.ident, &ident, sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
		wdt_get_status(&status);
		return put_user(status, uarg.i);

	case WDIOC_GETBOOTSTATUS:
		return put_user(0, uarg.i);

	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		return 0;

	case WDIOC_SETOPTIONS:
		if (get_user (new_options, uarg.i))
			return -EFAULT;

		if (new_options & WDIOS_DISABLECARD) {
			wdt_stop();
			retval = 0;
		}

		if (new_options & WDIOS_ENABLECARD) {
			wdt_start();
			retval = 0;
		}

		return retval;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, uarg.i))
			return -EFAULT;

		if (wdt_set_timeout(new_timeout))
		    return -EINVAL;

		wdt_keepalive();
		/* Fall */

	case WDIOC_GETTIMEOUT:
		return put_user(timeout, uarg.i);

	}
}

static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
	void *unused)
{
	if (code==SYS_DOWN || code==SYS_HALT)
		wdt_stop();
	return NOTIFY_DONE;
}

static const struct file_operations wdt_fops=
{
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= wdt_write,
	.ioctl		= wdt_ioctl,
	.open		= wdt_open,
	.release	= wdt_release,
};

static struct miscdevice wdt_miscdev=
{
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &wdt_fops,
};

static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};

static int __init w83977f_wdt_init(void)
{
	int rc;

        printk(KERN_INFO PFX DRIVER_VERSION);

	spin_lock_init(&spinlock);

	/*
	 * Check that the timeout value is within it's range ; 
	 * if not reset to the default
	 */
	if (wdt_set_timeout(timeout)) {
		wdt_set_timeout(DEFAULT_TIMEOUT);
		printk(KERN_INFO PFX "timeout value must be 15<=timeout<=7635, using %d\n",
			DEFAULT_TIMEOUT);
	}

	if (!request_region(IO_INDEX_PORT, 2, WATCHDOG_NAME))
	{
		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
			IO_INDEX_PORT);
		rc = -EIO;
		goto err_out;
	}

	rc = misc_register(&wdt_miscdev);
	if (rc)
	{
		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
			wdt_miscdev.minor, rc);
		goto err_out_region;
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc)
	{
		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
			rc);
		goto err_out_miscdev;
	}

	printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
		timeout, nowayout, testmode);

	return 0;

err_out_miscdev:
	misc_deregister(&wdt_miscdev);
err_out_region:
	release_region(IO_INDEX_PORT,2);
err_out:
	return rc;
}

static void __exit w83977f_wdt_exit(void)
{
	wdt_stop();
	misc_deregister(&wdt_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	release_region(IO_INDEX_PORT,2);
}

module_init(w83977f_wdt_init);
module_exit(w83977f_wdt_exit);

MODULE_AUTHOR("Jose Goncalves <jose.goncalves@inov.pt>");
MODULE_DESCRIPTION("Driver for watchdog timer in W83977F I/O chip");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
OpenPOWER on IntegriCloud