summaryrefslogtreecommitdiff
path: root/drivers/watchdog/it8712f_wdt.c
blob: 41b3979a9d87068c3cbf3ad5ce9cb430d122ae5a (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
/*
 *	IT8712F "Smart Guardian" Watchdog support
 *
 *	Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
 *
 *	Based on info and code taken from:
 *
 *	drivers/char/watchdog/scx200_wdt.c
 *	drivers/hwmon/it87.c
 *	IT8712F EC-LPC I/O Preliminary Specification 0.8.2
 *	IT8712F EC-LPC I/O Preliminary Specification 0.9.3
 *
 *	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 author(s) of this software shall not be held liable for damages
 *	of any nature resulting due to the use of this software. This
 *	software is provided AS-IS with no warranties.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define DEBUG
#define NAME "it8712f_wdt"

MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
MODULE_DESCRIPTION("IT8712F Watchdog Driver");
MODULE_LICENSE("GPL");

static int max_units = 255;
static int margin = 60;		/* in seconds */
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds");

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");

static unsigned long wdt_open;
static unsigned expect_close;
static unsigned char revision;

/* Dog Food address - We use the game port address */
static unsigned short address;

#define	REG		0x2e	/* The register to read/write */
#define	VAL		0x2f	/* The value to read/write */

#define	LDN		0x07	/* Register: Logical device select */
#define	DEVID		0x20	/* Register: Device ID */
#define	DEVREV		0x22	/* Register: Device Revision */
#define ACT_REG		0x30	/* LDN Register: Activation */
#define BASE_REG	0x60	/* LDN Register: Base address */

#define IT8712F_DEVID	0x8712

#define LDN_GPIO	0x07	/* GPIO and Watch Dog Timer */
#define LDN_GAME	0x09	/* Game Port */

#define WDT_CONTROL	0x71	/* WDT Register: Control */
#define WDT_CONFIG	0x72	/* WDT Register: Configuration */
#define WDT_TIMEOUT	0x73	/* WDT Register: Timeout Value */

#define WDT_RESET_GAME	0x10	/* Reset timer on read or write to game port */
#define WDT_RESET_KBD	0x20	/* Reset timer on keyboard interrupt */
#define WDT_RESET_MOUSE	0x40	/* Reset timer on mouse interrupt */
#define WDT_RESET_CIR	0x80	/* Reset timer on consumer IR interrupt */

#define WDT_UNIT_SEC	0x80	/* If 0 in MINUTES */

#define WDT_OUT_PWROK	0x10	/* Pulse PWROK on timeout */
#define WDT_OUT_KRST	0x40	/* Pulse reset on timeout */

static int wdt_control_reg = WDT_RESET_GAME;
module_param(wdt_control_reg, int, 0);
MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
		"register. The default WDT_RESET_GAME resets the timer on "
		"game port reads that this driver generates. You can also "
		"use KBD, MOUSE or CIR if you have some external way to "
		"generate those interrupts.");

static int superio_inb(int reg)
{
	outb(reg, REG);
	return inb(VAL);
}

static void superio_outb(int val, int reg)
{
	outb(reg, REG);
	outb(val, VAL);
}

static int superio_inw(int reg)
{
	int val;
	outb(reg++, REG);
	val = inb(VAL) << 8;
	outb(reg, REG);
	val |= inb(VAL);
	return val;
}

static inline void superio_select(int ldn)
{
	outb(LDN, REG);
	outb(ldn, VAL);
}

static inline int superio_enter(void)
{
	/*
	 * Try to reserve REG and REG + 1 for exclusive access.
	 */
	if (!request_muxed_region(REG, 2, NAME))
		return -EBUSY;

	outb(0x87, REG);
	outb(0x01, REG);
	outb(0x55, REG);
	outb(0x55, REG);
	return 0;
}

static inline void superio_exit(void)
{
	outb(0x02, REG);
	outb(0x02, VAL);
	release_region(REG, 2);
}

static inline void it8712f_wdt_ping(void)
{
	if (wdt_control_reg & WDT_RESET_GAME)
		inb(address);
}

static void it8712f_wdt_update_margin(void)
{
	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
	int units = margin;

	/* Switch to minutes precision if the configured margin
	 * value does not fit within the register width.
	 */
	if (units <= max_units) {
		config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
		pr_info("timer margin %d seconds\n", units);
	} else {
		units /= 60;
		pr_info("timer margin %d minutes\n", units);
	}
	superio_outb(config, WDT_CONFIG);

	if (revision >= 0x08)
		superio_outb(units >> 8, WDT_TIMEOUT + 1);
	superio_outb(units, WDT_TIMEOUT);
}

static int it8712f_wdt_get_status(void)
{
	if (superio_inb(WDT_CONTROL) & 0x01)
		return WDIOF_CARDRESET;
	else
		return 0;
}

static int it8712f_wdt_enable(void)
{
	int ret = superio_enter();
	if (ret)
		return ret;

	pr_debug("enabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(wdt_control_reg, WDT_CONTROL);

	it8712f_wdt_update_margin();

	superio_exit();

	it8712f_wdt_ping();

	return 0;
}

static int it8712f_wdt_disable(void)
{
	int ret = superio_enter();
	if (ret)
		return ret;

	pr_debug("disabling watchdog timer\n");
	superio_select(LDN_GPIO);

	superio_outb(0, WDT_CONFIG);
	superio_outb(0, WDT_CONTROL);
	if (revision >= 0x08)
		superio_outb(0, WDT_TIMEOUT + 1);
	superio_outb(0, WDT_TIMEOUT);

	superio_exit();
	return 0;
}

static int it8712f_wdt_notify(struct notifier_block *this,
		    unsigned long code, void *unused)
{
	if (code == SYS_HALT || code == SYS_POWER_OFF)
		if (!nowayout)
			it8712f_wdt_disable();

	return NOTIFY_DONE;
}

static struct notifier_block it8712f_wdt_notifier = {
	.notifier_call = it8712f_wdt_notify,
};

static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
					size_t len, loff_t *ppos)
{
	/* check for a magic close character */
	if (len) {
		size_t i;

		it8712f_wdt_ping();

		expect_close = 0;
		for (i = 0; i < len; ++i) {
			char c;
			if (get_user(c, data + i))
				return -EFAULT;
			if (c == 'V')
				expect_close = 42;
		}
	}

	return len;
}

static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.identity = "IT8712F Watchdog",
		.firmware_version = 1,
		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
						WDIOF_MAGICCLOSE,
	};
	int value;
	int ret;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		return 0;
	case WDIOC_GETSTATUS:
		ret = superio_enter();
		if (ret)
			return ret;
		superio_select(LDN_GPIO);

		value = it8712f_wdt_get_status();

		superio_exit();

		return put_user(value, p);
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_KEEPALIVE:
		it8712f_wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(value, p))
			return -EFAULT;
		if (value < 1)
			return -EINVAL;
		if (value > (max_units * 60))
			return -EINVAL;
		margin = value;
		ret = superio_enter();
		if (ret)
			return ret;
		superio_select(LDN_GPIO);

		it8712f_wdt_update_margin();

		superio_exit();
		it8712f_wdt_ping();
		/* Fall through */
	case WDIOC_GETTIMEOUT:
		if (put_user(margin, p))
			return -EFAULT;
		return 0;
	default:
		return -ENOTTY;
	}
}

static int it8712f_wdt_open(struct inode *inode, struct file *file)
{
	int ret;
	/* only allow one at a time */
	if (test_and_set_bit(0, &wdt_open))
		return -EBUSY;

	ret = it8712f_wdt_enable();
	if (ret)
		return ret;
	return nonseekable_open(inode, file);
}

static int it8712f_wdt_release(struct inode *inode, struct file *file)
{
	if (expect_close != 42) {
		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
	} else if (!nowayout) {
		if (it8712f_wdt_disable())
			pr_warn("Watchdog disable failed\n");
	}
	expect_close = 0;
	clear_bit(0, &wdt_open);

	return 0;
}

static const struct file_operations it8712f_wdt_fops = {
	.owner = THIS_MODULE,
	.llseek = no_llseek,
	.write = it8712f_wdt_write,
	.unlocked_ioctl = it8712f_wdt_ioctl,
	.open = it8712f_wdt_open,
	.release = it8712f_wdt_release,
};

static struct miscdevice it8712f_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &it8712f_wdt_fops,
};

static int __init it8712f_wdt_find(unsigned short *address)
{
	int err = -ENODEV;
	int chip_type;
	int ret = superio_enter();
	if (ret)
		return ret;

	chip_type = superio_inw(DEVID);
	if (chip_type != IT8712F_DEVID)
		goto exit;

	superio_select(LDN_GAME);
	superio_outb(1, ACT_REG);
	if (!(superio_inb(ACT_REG) & 0x01)) {
		pr_err("Device not activated, skipping\n");
		goto exit;
	}

	*address = superio_inw(BASE_REG);
	if (*address == 0) {
		pr_err("Base address not set, skipping\n");
		goto exit;
	}

	err = 0;
	revision = superio_inb(DEVREV) & 0x0f;

	/* Later revisions have 16-bit values per datasheet 0.9.1 */
	if (revision >= 0x08)
		max_units = 65535;

	if (margin > (max_units * 60))
		margin = (max_units * 60);

	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
		chip_type, revision, *address);

exit:
	superio_exit();
	return err;
}

static int __init it8712f_wdt_init(void)
{
	int err = 0;

	if (it8712f_wdt_find(&address))
		return -ENODEV;

	if (!request_region(address, 1, "IT8712F Watchdog")) {
		pr_warn("watchdog I/O region busy\n");
		return -EBUSY;
	}

	err = it8712f_wdt_disable();
	if (err) {
		pr_err("unable to disable watchdog timer\n");
		goto out;
	}

	err = register_reboot_notifier(&it8712f_wdt_notifier);
	if (err) {
		pr_err("unable to register reboot notifier\n");
		goto out;
	}

	err = misc_register(&it8712f_wdt_miscdev);
	if (err) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, err);
		goto reboot_out;
	}

	return 0;


reboot_out:
	unregister_reboot_notifier(&it8712f_wdt_notifier);
out:
	release_region(address, 1);
	return err;
}

static void __exit it8712f_wdt_exit(void)
{
	misc_deregister(&it8712f_wdt_miscdev);
	unregister_reboot_notifier(&it8712f_wdt_notifier);
	release_region(address, 1);
}

module_init(it8712f_wdt_init);
module_exit(it8712f_wdt_exit);