summaryrefslogtreecommitdiff
path: root/drivers/watchdog/pc87413_wdt.c
blob: 5211d56b368183ca1b1dc7de2bfe97adcde90efd (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
/*
 *      NS pc87413-wdt Watchdog Timer driver for Linux 2.6.x.x
 *
 *      This code is based on wdt.c with original copyright.
 *
 *      (C) Copyright 2006 Sven Anders, <anders@anduras.de>
 *                     and Marcus Junker, <junker@anduras.de>
 *
 *      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.
 *
 *      Neither Sven Anders, Marcus Junker nor ANDURAS AG
 *      admit liability nor provide warranty for any of this software.
 *      This material is provided "AS-IS" and at no charge.
 *
 *      Release 1.1
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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


/* #define DEBUG 1 */

#define DEFAULT_TIMEOUT     1		/* 1 minute */
#define MAX_TIMEOUT         255

#define VERSION             "1.1"
#define MODNAME             "pc87413 WDT"
#define DPFX                MODNAME " - DEBUG: "

#define WDT_INDEX_IO_PORT   (io+0)	/* I/O port base (index register) */
#define WDT_DATA_IO_PORT    (WDT_INDEX_IO_PORT+1)
#define SWC_LDN             0x04
#define SIOCFG2             0x22	/* Serial IO register */
#define WDCTL               0x10	/* Watchdog-Timer-Control-Register */
#define WDTO                0x11	/* Watchdog timeout register */
#define WDCFG               0x12	/* Watchdog config register */

#define IO_DEFAULT	0x2E		/* Address used on Portwell Boards */

static int io = IO_DEFAULT;
static int swc_base_addr = -1;

static int timeout = DEFAULT_TIMEOUT;	/* timeout value */
static unsigned long timer_enabled;	/* is the timer enabled? */

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

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

static bool nowayout = WATCHDOG_NOWAYOUT;

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

/* Select pins for Watchdog output */

static inline void pc87413_select_wdt_out(void)
{
	unsigned int cr_data = 0;

	/* Step 1: Select multiple pin,pin55,as WDT output */

	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);

	cr_data = inb(WDT_DATA_IO_PORT);

	cr_data |= 0x80; /* Set Bit7 to 1*/
	outb_p(SIOCFG2, WDT_INDEX_IO_PORT);

	outb_p(cr_data, WDT_DATA_IO_PORT);

#ifdef DEBUG
	pr_info(DPFX
		"Select multiple pin,pin55,as WDT output: Bit7 to 1: %d\n",
								cr_data);
#endif
}

/* Enable SWC functions */

static inline void pc87413_enable_swc(void)
{
	unsigned int cr_data = 0;

	/* Step 2: Enable SWC functions */

	outb_p(0x07, WDT_INDEX_IO_PORT);	/* Point SWC_LDN (LDN=4) */
	outb_p(SWC_LDN, WDT_DATA_IO_PORT);

	outb_p(0x30, WDT_INDEX_IO_PORT);	/* Read Index 0x30 First */
	cr_data = inb(WDT_DATA_IO_PORT);
	cr_data |= 0x01;			/* Set Bit0 to 1 */
	outb_p(0x30, WDT_INDEX_IO_PORT);
	outb_p(cr_data, WDT_DATA_IO_PORT);	/* Index0x30_bit0P1 */

#ifdef DEBUG
	pr_info(DPFX "pc87413 - Enable SWC functions\n");
#endif
}

/* Read SWC I/O base address */

static void pc87413_get_swc_base_addr(void)
{
	unsigned char addr_l, addr_h = 0;

	/* Step 3: Read SWC I/O Base Address */

	outb_p(0x60, WDT_INDEX_IO_PORT);	/* Read Index 0x60 */
	addr_h = inb(WDT_DATA_IO_PORT);

	outb_p(0x61, WDT_INDEX_IO_PORT);	/* Read Index 0x61 */

	addr_l = inb(WDT_DATA_IO_PORT);

	swc_base_addr = (addr_h << 8) + addr_l;
#ifdef DEBUG
	pr_info(DPFX
		"Read SWC I/O Base Address: low %d, high %d, res %d\n",
						addr_l, addr_h, swc_base_addr);
#endif
}

/* Select Bank 3 of SWC */

static inline void pc87413_swc_bank3(void)
{
	/* Step 4: Select Bank3 of SWC */
	outb_p(inb(swc_base_addr + 0x0f) | 0x03, swc_base_addr + 0x0f);
#ifdef DEBUG
	pr_info(DPFX "Select Bank3 of SWC\n");
#endif
}

/* Set watchdog timeout to x minutes */

static inline void pc87413_programm_wdto(char pc87413_time)
{
	/* Step 5: Programm WDTO, Twd. */
	outb_p(pc87413_time, swc_base_addr + WDTO);
#ifdef DEBUG
	pr_info(DPFX "Set WDTO to %d minutes\n", pc87413_time);
#endif
}

/* Enable WDEN */

static inline void pc87413_enable_wden(void)
{
	/* Step 6: Enable WDEN */
	outb_p(inb(swc_base_addr + WDCTL) | 0x01, swc_base_addr + WDCTL);
#ifdef DEBUG
	pr_info(DPFX "Enable WDEN\n");
#endif
}

/* Enable SW_WD_TREN */
static inline void pc87413_enable_sw_wd_tren(void)
{
	/* Enable SW_WD_TREN */
	outb_p(inb(swc_base_addr + WDCFG) | 0x80, swc_base_addr + WDCFG);
#ifdef DEBUG
	pr_info(DPFX "Enable SW_WD_TREN\n");
#endif
}

/* Disable SW_WD_TREN */

static inline void pc87413_disable_sw_wd_tren(void)
{
	/* Disable SW_WD_TREN */
	outb_p(inb(swc_base_addr + WDCFG) & 0x7f, swc_base_addr + WDCFG);
#ifdef DEBUG
	pr_info(DPFX "pc87413 - Disable SW_WD_TREN\n");
#endif
}

/* Enable SW_WD_TRG */

static inline void pc87413_enable_sw_wd_trg(void)
{
	/* Enable SW_WD_TRG */
	outb_p(inb(swc_base_addr + WDCTL) | 0x80, swc_base_addr + WDCTL);
#ifdef DEBUG
	pr_info(DPFX "pc87413 - Enable SW_WD_TRG\n");
#endif
}

/* Disable SW_WD_TRG */

static inline void pc87413_disable_sw_wd_trg(void)
{
	/* Disable SW_WD_TRG */
	outb_p(inb(swc_base_addr + WDCTL) & 0x7f, swc_base_addr + WDCTL);
#ifdef DEBUG
	pr_info(DPFX "Disable SW_WD_TRG\n");
#endif
}

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

/* Enable the watchdog */

static void pc87413_enable(void)
{
	spin_lock(&io_lock);

	pc87413_swc_bank3();
	pc87413_programm_wdto(timeout);
	pc87413_enable_wden();
	pc87413_enable_sw_wd_tren();
	pc87413_enable_sw_wd_trg();

	spin_unlock(&io_lock);
}

/* Disable the watchdog */

static void pc87413_disable(void)
{
	spin_lock(&io_lock);

	pc87413_swc_bank3();
	pc87413_disable_sw_wd_tren();
	pc87413_disable_sw_wd_trg();
	pc87413_programm_wdto(0);

	spin_unlock(&io_lock);
}

/* Refresh the watchdog */

static void pc87413_refresh(void)
{
	spin_lock(&io_lock);

	pc87413_swc_bank3();
	pc87413_disable_sw_wd_tren();
	pc87413_disable_sw_wd_trg();
	pc87413_programm_wdto(timeout);
	pc87413_enable_wden();
	pc87413_enable_sw_wd_tren();
	pc87413_enable_sw_wd_trg();

	spin_unlock(&io_lock);
}

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

/**
 *	pc87413_open:
 *	@inode: inode of device
 *	@file: file handle to device
 *
 */

static int pc87413_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 */
	pc87413_refresh();

	pr_info("Watchdog enabled. Timeout set to %d minute(s).\n", timeout);

	return nonseekable_open(inode, file);
}

/**
 *	pc87413_release:
 *	@inode: inode to board
 *	@file: file handle to board
 *
 *	The watchdog has a configurable API. There is a religious dispute
 *	between people who want their watchdog to be able to shut down and
 *	those who want to be sure if the watchdog manager dies the machine
 *	reboots. In the former case we disable the counters, in the latter
 *	case you have to open it again very soon.
 */

static int pc87413_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer. */

	if (expect_close == 42) {
		pc87413_disable();
		pr_info("Watchdog disabled, sleeping again...\n");
	} else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		pc87413_refresh();
	}
	clear_bit(0, &timer_enabled);
	expect_close = 0;
	return 0;
}

/**
 *	pc87413_status:
 *
 *      return, if the watchdog is enabled (timeout is set...)
 */


static int pc87413_status(void)
{
	  return 0; /* currently not supported */
}

/**
 *	pc87413_write:
 *	@file: file handle to the watchdog
 *	@data: data buffer to write
 *	@len: length in 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 pc87413_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 */
		pc87413_refresh();
	}
	return len;
}

/**
 *	pc87413_ioctl:
 *	@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. We only actually usefully support
 *	querying capabilities and current status.
 */

static long pc87413_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 = 1,
		.identity         = "PC87413(HF/F) 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(pc87413_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) {
			pc87413_disable();
			retval = 0;
		}
		if (options & WDIOS_ENABLECARD) {
			pc87413_enable();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		pc87413_refresh();
#ifdef DEBUG
		pr_info(DPFX "keepalive\n");
#endif
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_timeout, uarg.i))
			return -EFAULT;
		/* the API states this is given in secs */
		new_timeout /= 60;
		if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
			return -EINVAL;
		timeout = new_timeout;
		pc87413_refresh();
		/* fall through and return the new timeout... */
	case WDIOC_GETTIMEOUT:
		new_timeout = timeout * 60;
		return put_user(new_timeout, uarg.i);
	default:
		return -ENOTTY;
	}
}

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

/**
 *	notify_sys:
 *	@this: our notifier block
 *	@code: the event being reported
 *	@unused: unused
 *
 *	Our notifier is called on system shutdowns. We want to turn the card
 *	off at reboot otherwise the machine will reboot again during memory
 *	test or worse yet during the following fsck. This would suck, in fact
 *	trust me - if it happens it does suck.
 */

static int pc87413_notify_sys(struct notifier_block *this,
			      unsigned long code,
			      void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		/* Turn the card off */
		pc87413_disable();
	return NOTIFY_DONE;
}

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

static const struct file_operations pc87413_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= pc87413_write,
	.unlocked_ioctl	= pc87413_ioctl,
	.open		= pc87413_open,
	.release	= pc87413_release,
};

static struct notifier_block pc87413_notifier = {
	.notifier_call  = pc87413_notify_sys,
};

static struct miscdevice pc87413_miscdev = {
	.minor          = WATCHDOG_MINOR,
	.name           = "watchdog",
	.fops           = &pc87413_fops,
};

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

/**
 *	pc87413_init: module's "constructor"
 *
 *	Set up the WDT watchdog board. All we have to do is grab the
 *	resources we require and bitch if anyone beat us to them.
 *	The open() function will actually kick the board off.
 */

static int __init pc87413_init(void)
{
	int ret;

	pr_info("Version " VERSION " at io 0x%X\n",
							WDT_INDEX_IO_PORT);

	if (!request_muxed_region(io, 2, MODNAME))
		return -EBUSY;

	ret = register_reboot_notifier(&pc87413_notifier);
	if (ret != 0) {
		pr_err("cannot register reboot notifier (err=%d)\n", ret);
	}

	ret = misc_register(&pc87413_miscdev);
	if (ret != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto reboot_unreg;
	}
	pr_info("initialized. timeout=%d min\n", timeout);

	pc87413_select_wdt_out();
	pc87413_enable_swc();
	pc87413_get_swc_base_addr();

	if (!request_region(swc_base_addr, 0x20, MODNAME)) {
		pr_err("cannot request SWC region at 0x%x\n", swc_base_addr);
		ret = -EBUSY;
		goto misc_unreg;
	}

	pc87413_enable();

	release_region(io, 2);
	return 0;

misc_unreg:
	misc_deregister(&pc87413_miscdev);
reboot_unreg:
	unregister_reboot_notifier(&pc87413_notifier);
	release_region(io, 2);
	return ret;
}

/**
 *	pc87413_exit: module's "destructor"
 *
 *	Unload the watchdog. You cannot do this with any file handles open.
 *	If your watchdog is set to continue ticking on close and you unload
 *	it, well it keeps ticking. We won't get the interrupt but the board
 *	will not touch PC memory so all is fine. You just have to load a new
 *	module in 60 seconds or reboot.
 */

static void __exit pc87413_exit(void)
{
	/* Stop the timer before we leave */
	if (!nowayout) {
		pc87413_disable();
		pr_info("Watchdog disabled\n");
	}

	misc_deregister(&pc87413_miscdev);
	unregister_reboot_notifier(&pc87413_notifier);
	release_region(swc_base_addr, 0x20);

	pr_info("watchdog component driver removed\n");
}

module_init(pc87413_init);
module_exit(pc87413_exit);

MODULE_AUTHOR("Sven Anders <anders@anduras.de>, "
		"Marcus Junker <junker@anduras.de>,");
MODULE_DESCRIPTION("PC87413 WDT driver");
MODULE_LICENSE("GPL");

module_param(io, int, 0);
MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
					__MODULE_STRING(IO_DEFAULT) ").");

module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Watchdog timeout in minutes (default="
				__MODULE_STRING(DEFAULT_TIMEOUT) ").");

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