summaryrefslogtreecommitdiff
path: root/drivers/watchdog/smsc37b787_wdt.c
blob: 239383da6d8784b94961946e6c044dbb850ca48d (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
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
/*
 *	SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
 *
 *      Based on acquirewdt.c by Alan Cox <alan@redhat.com>
 *       and some other existing drivers
 *
 *	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.
 *
 *	The authors do NOT admit liability nor provide warranty for
 *	any of this software. This material is provided "AS-IS" in
 *      the hope that it may be useful for others.
 *
 *	(C) Copyright 2003-2006  Sven Anders <anders@anduras.de>
 *
 *  History:
 *	2003 - Created version 1.0 for Linux 2.4.x.
 *	2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
 *	       features. Released version 1.1
 *
 *  Theory of operation:
 *
 *      A Watchdog Timer (WDT) is a hardware circuit that can
 *      reset the computer system in case of a software fault.
 *      You probably knew that already.
 *
 *      Usually a userspace daemon will notify the kernel WDT driver
 *      via the /dev/watchdog special device file that userspace is
 *      still alive, at regular intervals.  When such a notification
 *      occurs, the driver will usually tell the hardware watchdog
 *      that everything is in order, and that the watchdog should wait
 *      for yet another little while to reset the system.
 *      If userspace fails (RAM error, kernel bug, whatever), the
 *      notifications cease to occur, and the hardware watchdog will
 *      reset the system (causing a reboot) after the timeout occurs.
 *
 * Create device with:
 *  mknod /dev/watchdog c 10 130
 *
 * For an example userspace keep-alive daemon, see:
 *   Documentation/watchdog/watchdog.txt
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/io.h>
#include <linux/uaccess.h>

#include <asm/system.h>

/* enable support for minutes as units? */
/* (does not always work correctly, so disabled by default!) */
#define SMSC_SUPPORT_MINUTES
#undef SMSC_SUPPORT_MINUTES

#define MAX_TIMEOUT     255

#define UNIT_SECOND     0
#define UNIT_MINUTE     1

#define MODNAME		"smsc37b787_wdt: "
#define VERSION		"1.1"

#define IOPORT		0x3F0
#define IOPORT_SIZE     2
#define IODEV_NO	8

static int unit = UNIT_SECOND;	/* timer's unit */
static int timeout = 60;	/* timeout value: default is 60 "units" */
static unsigned long timer_enabled;   /* is the timer enabled? */

static char expect_close;       /* is the close expected? */

static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */

static int nowayout = WATCHDOG_NOWAYOUT;

/* -- Low level function ----------------------------------------*/

/* unlock the IO chip */

static inline void open_io_config(void)
{
	outb(0x55, IOPORT);
	mdelay(1);
	outb(0x55, IOPORT);
}

/* lock the IO chip */
static inline void close_io_config(void)
{
	outb(0xAA, IOPORT);
}

/* select the IO device */
static inline void select_io_device(unsigned char devno)
{
	outb(0x07, IOPORT);
	outb(devno, IOPORT+1);
}

/* write to the control register */
static inline void write_io_cr(unsigned char reg, unsigned char data)
{
	outb(reg, IOPORT);
	outb(data, IOPORT+1);
}

/* read from the control register */
static inline char read_io_cr(unsigned char reg)
{
	outb(reg, IOPORT);
	return inb(IOPORT+1);
}

/* -- Medium level functions ------------------------------------*/

static inline void gpio_bit12(unsigned char reg)
{
	/* -- General Purpose I/O Bit 1.2 --
	 * Bit 0,   In/Out: 0 = Output, 1 = Input
	 * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
	 * Bit 2,   Group Enable Intr.: 0 = Disable, 1 = Enable
	 * Bit 3/4, Function select: 00 = GPI/O, 01 = WDT, 10 = P17,
	 *                           11 = Either Edge Triggered Intr. 2
	 * Bit 5/6  (Reserved)
	 * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
	 */
	write_io_cr(0xE2, reg);
}

static inline void gpio_bit13(unsigned char reg)
{
	/* -- General Purpose I/O Bit 1.3 --
	 * Bit 0,  In/Out: 0 = Output, 1 = Input
	 * Bit 1,  Polarity: 0 = No Invert, 1 = Invert
	 * Bit 2,  Group Enable Intr.: 0 = Disable, 1 = Enable
	 * Bit 3,  Function select: 0 = GPI/O, 1 = LED
	 * Bit 4-6 (Reserved)
	 * Bit 7,  Output Type: 0 = Push Pull Bit, 1 = Open Drain
	 */
	write_io_cr(0xE3, reg);
}

static inline void wdt_timer_units(unsigned char new_units)
{
	/* -- Watchdog timer units --
	 * Bit 0-6 (Reserved)
	 * Bit 7,  WDT Time-out Value Units Select
	 *         (0 = Minutes, 1 = Seconds)
	 */
	write_io_cr(0xF1, new_units);
}

static inline void wdt_timeout_value(unsigned char new_timeout)
{
	/* -- Watchdog Timer Time-out Value --
	 * Bit 0-7 Binary coded units (0=Disabled, 1..255)
	 */
	write_io_cr(0xF2, new_timeout);
}

static inline void wdt_timer_conf(unsigned char conf)
{
	/* -- Watchdog timer configuration --
	 * Bit 0   Joystick enable: 0* = No Reset, 1 = Reset WDT upon
	 *							Gameport I/O
	 * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
	 * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
	 * Bit 3   Reset the timer
	 *         (Wrong in SMsC documentation? Given as: PowerLED Timout
	 *							Enabled)
	 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
	 *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
	 */
	write_io_cr(0xF3, conf);
}

static inline void wdt_timer_ctrl(unsigned char reg)
{
	/* -- Watchdog timer control --
	 * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occured
	 * Bit 1   Power LED Toggle: 0 = Disable Toggle, 1 = Toggle at 1 Hz
	 * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
	 * Bit 3   P20 Force Timeout enabled:
	 *          0 = P20 activity does not generate the WD timeout event
	 *          1 = P20 Allows rising edge of P20, from the keyboard
	 *              controller, to force the WD timeout event.
	 * Bit 4   (Reserved)
	 * -- Soft power management --
	 * Bit 5   Stop Counter: 1 = Stop software power down counter
	 *            set via register 0xB8, (self-cleaning)
	 *            (Upon read: 0 = Counter running, 1 = Counter stopped)
	 * Bit 6   Restart Counter: 1 = Restart software power down counter
	 *            set via register 0xB8, (self-cleaning)
	 * Bit 7   SPOFF: 1 = Force software power down (self-cleaning)
	 */
	write_io_cr(0xF4, reg);
}

/* -- Higher level functions ------------------------------------*/

/* initialize watchdog */

static void wb_smsc_wdt_initialize(void)
{
	unsigned char old;

	spin_lock(&io_lock);
	open_io_config();
	select_io_device(IODEV_NO);

	/* enable the watchdog */
	gpio_bit13(0x08);  /* Select pin 80 = LED not GPIO */
	gpio_bit12(0x0A);  /* Set pin 79 = WDT not
			      GPIO/Output/Polarity=Invert */
	/* disable the timeout */
	wdt_timeout_value(0);

	/* reset control register */
	wdt_timer_ctrl(0x00);

	/* reset configuration register */
	wdt_timer_conf(0x00);

	/* read old (timer units) register */
	old = read_io_cr(0xF1) & 0x7F;
	if (unit == UNIT_SECOND)
		old |= 0x80;	/* set to seconds */

	/* set the watchdog timer units */
	wdt_timer_units(old);

	close_io_config();
	spin_unlock(&io_lock);
}

/* shutdown the watchdog */

static void wb_smsc_wdt_shutdown(void)
{
	spin_lock(&io_lock);
	open_io_config();
	select_io_device(IODEV_NO);

	/* disable the watchdog */
	gpio_bit13(0x09);
	gpio_bit12(0x09);

	/* reset watchdog config register */
	wdt_timer_conf(0x00);

	/* reset watchdog control register */
	wdt_timer_ctrl(0x00);

	/* disable timeout */
	wdt_timeout_value(0x00);

	close_io_config();
	spin_unlock(&io_lock);
}

/* set timeout => enable watchdog */

static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
{
	spin_lock(&io_lock);
	open_io_config();
	select_io_device(IODEV_NO);

	/* set Power LED to blink, if we enable the timeout */
	wdt_timer_ctrl((new_timeout == 0) ? 0x00 : 0x02);

	/* set timeout value */
	wdt_timeout_value(new_timeout);

	close_io_config();
	spin_unlock(&io_lock);
}

/* get timeout */

static unsigned char wb_smsc_wdt_get_timeout(void)
{
	unsigned char set_timeout;

	spin_lock(&io_lock);
	open_io_config();
	select_io_device(IODEV_NO);
	set_timeout = read_io_cr(0xF2);
	close_io_config();
	spin_unlock(&io_lock);

	return set_timeout;
}

/* disable watchdog */

static void wb_smsc_wdt_disable(void)
{
	/* set the timeout to 0 to disable the watchdog */
	wb_smsc_wdt_set_timeout(0);
}

/* enable watchdog by setting the current timeout */

static void wb_smsc_wdt_enable(void)
{
	/* set the current timeout... */
	wb_smsc_wdt_set_timeout(timeout);
}

/* reset the timer */

static void wb_smsc_wdt_reset_timer(void)
{
	spin_lock(&io_lock);
	open_io_config();
	select_io_device(IODEV_NO);

	/* reset the timer */
	wdt_timeout_value(timeout);
	wdt_timer_conf(0x08);

	close_io_config();
	spin_unlock(&io_lock);
}

/* return, if the watchdog is enabled (timeout is set...) */

static int wb_smsc_wdt_status(void)
{
	return (wb_smsc_wdt_get_timeout() == 0) ? 0 : WDIOF_KEEPALIVEPING;
}


/* -- File operations -------------------------------------------*/

/* open => enable watchdog and set initial timeout */

static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */

	if (test_and_set_bit(0, &timer_enabled))
		return -EBUSY;

	if (nowayout)
		__module_get(THIS_MODULE);

	/* Reload and activate timer */
	wb_smsc_wdt_enable();

	printk(KERN_INFO MODNAME
		"Watchdog enabled. Timeout set to %d %s.\n",
		timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");

	return nonseekable_open(inode, file);
}

/* close => shut off the timer */

static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer. */

	if (expect_close == 42) {
		wb_smsc_wdt_disable();
		printk(KERN_INFO MODNAME
				"Watchdog disabled, sleeping again...\n");
	} else {
		printk(KERN_CRIT MODNAME
				"Unexpected close, not stopping watchdog!\n");
		wb_smsc_wdt_reset_timer();
	}

	clear_bit(0, &timer_enabled);
	expect_close = 0;
	return 0;
}

/* write => update the timer to keep the machine alive */

static ssize_t wb_smsc_wdt_write(struct file *file, const char __user *data,
				 size_t len, loff_t *ppos)
{
	/* See if we got the magic character 'V' and reload the timer */
	if (len) {
		if (!nowayout) {
			size_t i;

			/* reset expect flag */
			expect_close = 0;

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

		/* someone wrote to us, we should reload the timer */
		wb_smsc_wdt_reset_timer();
	}
	return len;
}

/* ioctl => control interface */

static long wb_smsc_wdt_ioctl(struct file *file,
					unsigned int cmd, unsigned long arg)
{
	int new_timeout;

	union {
		struct watchdog_info __user *ident;
		int __user *i;
	} uarg;

	static const struct watchdog_info ident = {
		.options = 		WDIOF_KEEPALIVEPING |
					WDIOF_SETTIMEOUT |
					WDIOF_MAGICCLOSE,
		.firmware_version =	0,
		.identity = 		"SMsC 37B787 Watchdog"
	};

	uarg.i = (int __user *)arg;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(uarg.ident, &ident, sizeof(ident))
								? -EFAULT : 0;
	case WDIOC_GETSTATUS:
		return put_user(wb_smsc_wdt_status(), uarg.i);
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, uarg.i);
	case WDIOC_SETOPTIONS:
	{
		int options, retval = -EINVAL;

		if (get_user(options, uarg.i))
			return -EFAULT;

		if (options & WDIOS_DISABLECARD) {
			wb_smsc_wdt_disable();
			retval = 0;
		}
		if (options & WDIOS_ENABLECARD) {
			wb_smsc_wdt_enable();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		wb_smsc_wdt_reset_timer();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, uarg.i))
			return -EFAULT;
		/* the API states this is given in secs */
		if (unit == UNIT_MINUTE)
			new_timeout /= 60;
		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
			return -EINVAL;
		timeout = new_timeout;
		wb_smsc_wdt_set_timeout(timeout);
		/* fall through and return the new timeout... */
	case WDIOC_GETTIMEOUT:
		new_timeout = timeout;
		if (unit == UNIT_MINUTE)
			  new_timeout *= 60;
		return put_user(new_timeout, uarg.i);
	default:
		return -ENOTTY;
	}
}

/* -- Notifier funtions -----------------------------------------*/

static int wb_smsc_wdt_notify_sys(struct notifier_block *this,
					unsigned long code, void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT) {
		/* set timeout to 0, to avoid possible race-condition */
		timeout = 0;
		wb_smsc_wdt_disable();
	}
	return NOTIFY_DONE;
}

/* -- Module's structures ---------------------------------------*/

static const struct file_operations wb_smsc_wdt_fops = {
	.owner	  = THIS_MODULE,
	.llseek		= no_llseek,
	.write		= wb_smsc_wdt_write,
	.unlocked_ioctl	= wb_smsc_wdt_ioctl,
	.open		= wb_smsc_wdt_open,
	.release	= wb_smsc_wdt_release,
};

static struct notifier_block wb_smsc_wdt_notifier = {
	.notifier_call  = wb_smsc_wdt_notify_sys,
};

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

/* -- Module init functions -------------------------------------*/

/* module's "constructor" */

static int __init wb_smsc_wdt_init(void)
{
	int ret;

	printk(KERN_INFO "SMsC 37B787 watchdog component driver "
					VERSION " initialising...\n");

	if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
		printk(KERN_ERR MODNAME "Unable to register IO port %#x\n",
								IOPORT);
		ret = -EBUSY;
		goto out_pnp;
	}

	/* set new maximum, if it's too big */
	if (timeout > MAX_TIMEOUT)
		timeout = MAX_TIMEOUT;

	/* init the watchdog timer */
	wb_smsc_wdt_initialize();

	ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
	if (ret) {
		printk(KERN_ERR MODNAME
			"Unable to register reboot notifier err = %d\n", ret);
		goto out_io;
	}

	ret = misc_register(&wb_smsc_wdt_miscdev);
	if (ret) {
		printk(KERN_ERR MODNAME
			"Unable to register miscdev on minor %d\n",
							WATCHDOG_MINOR);
		goto out_rbt;
	}

	/* output info */
	printk(KERN_INFO MODNAME "Timeout set to %d %s.\n",
		timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
	printk(KERN_INFO MODNAME
		"Watchdog initialized and sleeping (nowayout=%d)...\n",
								nowayout);
out_clean:
	return ret;

out_rbt:
	unregister_reboot_notifier(&wb_smsc_wdt_notifier);

out_io:
	release_region(IOPORT, IOPORT_SIZE);

out_pnp:
	goto out_clean;
}

/* module's "destructor" */

static void __exit wb_smsc_wdt_exit(void)
{
	/* Stop the timer before we leave */
	if (!nowayout) {
		wb_smsc_wdt_shutdown();
		printk(KERN_INFO MODNAME "Watchdog disabled.\n");
	}

	misc_deregister(&wb_smsc_wdt_miscdev);
	unregister_reboot_notifier(&wb_smsc_wdt_notifier);
	release_region(IOPORT, IOPORT_SIZE);

	printk(KERN_INFO "SMsC 37B787 watchdog component driver removed.\n");
}

module_init(wb_smsc_wdt_init);
module_exit(wb_smsc_wdt_exit);

MODULE_AUTHOR("Sven Anders <anders@anduras.de>");
MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version "
								VERSION ")");
MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

#ifdef SMSC_SUPPORT_MINUTES
module_param(unit, int, 0);
MODULE_PARM_DESC(unit,
		"set unit to use, 0=seconds or 1=minutes, default is 0");
#endif

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");

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