aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/alim1535_wdt.c
blob: 41b84936a521f62b81bec020646a7014e23e51bc (plain) (blame)
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
/*
 *	Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
 *
 *	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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#define WATCHDOG_NAME "ALi_M1535"
#define WATCHDOG_TIMEOUT 60	/* 60 sec default timeout */

/* internal variables */
static unsigned long ali_is_open;
static char ali_expect_release;
static struct pci_dev *ali_pci;
static u32 ali_timeout_bits;		/* stores the computed timeout */
static DEFINE_SPINLOCK(ali_lock);	/* Guards the hardware */

/* module parameters */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Watchdog timeout in seconds. (0 < timeout < 18000, default="
				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

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

/*
 *	ali_start	-	start watchdog countdown
 *
 *	Starts the timer running providing the timer has a counter
 *	configuration set.
 */

static void ali_start(void)
{
	u32 val;

	spin_lock(&ali_lock);

	pci_read_config_dword(ali_pci, 0xCC, &val);
	val &= ~0x3F;	/* Mask count */
	val |= (1 << 25) | ali_timeout_bits;
	pci_write_config_dword(ali_pci, 0xCC, val);

	spin_unlock(&ali_lock);
}

/*
 *	ali_stop	-	stop the timer countdown
 *
 *	Stop the ALi watchdog countdown
 */

static void ali_stop(void)
{
	u32 val;

	spin_lock(&ali_lock);

	pci_read_config_dword(ali_pci, 0xCC, &val);
	val &= ~0x3F;		/* Mask count to zero (disabled) */
	val &= ~(1 << 25);	/* and for safety mask the reset enable */
	pci_write_config_dword(ali_pci, 0xCC, val);

	spin_unlock(&ali_lock);
}

/*
 *	ali_keepalive	-	send a keepalive to the watchdog
 *
 *	Send a keepalive to the timer (actually we restart the timer).
 */

static void ali_keepalive(void)
{
	ali_start();
}

/*
 *	ali_settimer	-	compute the timer reload value
 *	@t: time in seconds
 *
 *	Computes the timeout values needed
 */

static int ali_settimer(int t)
{
	if (t < 0)
		return -EINVAL;
	else if (t < 60)
		ali_timeout_bits = t|(1 << 6);
	else if (t < 3600)
		ali_timeout_bits = (t / 60)|(1 << 7);
	else if (t < 18000)
		ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);
	else
		return -EINVAL;

	timeout = t;
	return 0;
}

/*
 *	/dev/watchdog handling
 */

/*
 *	ali_write	-	writes to ALi watchdog
 *	@file: file from VFS
 *	@data: user address of data
 *	@len: length of data
 *	@ppos: pointer to the file offset
 *
 *	Handle a write to the ALi watchdog. Writing to the file pings
 *	the watchdog and resets it. Writing the magic 'V' sequence allows
 *	the next close to turn off the watchdog.
 */

static ssize_t ali_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;

			/* note: just in case someone wrote the
			   magic character five months ago... */
			ali_expect_release = 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')
					ali_expect_release = 42;
			}
		}

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

/*
 *	ali_ioctl	-	handle watchdog ioctls
 *	@file: VFS file pointer
 *	@cmd: ioctl number
 *	@arg: arguments to the ioctl
 *
 *	Handle the watchdog ioctls supported by the ALi driver. Really
 *	we want an extension to enable irq ack monitoring and the like
 */

static long ali_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 = {
		.options =		WDIOF_KEEPALIVEPING |
					WDIOF_SETTIMEOUT |
					WDIOF_MAGICCLOSE,
		.firmware_version =	0,
		.identity =		"ALi M1535 WatchDog Timer",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(0, p);
	case WDIOC_SETOPTIONS:
	{
		int new_options, retval = -EINVAL;

		if (get_user(new_options, p))
			return -EFAULT;
		if (new_options & WDIOS_DISABLECARD) {
			ali_stop();
			retval = 0;
		}
		if (new_options & WDIOS_ENABLECARD) {
			ali_start();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		ali_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;
		if (get_user(new_timeout, p))
			return -EFAULT;
		if (ali_settimer(new_timeout))
			return -EINVAL;
		ali_keepalive();
		/* Fall */
	}
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	default:
		return -ENOTTY;
	}
}

/*
 *	ali_open	-	handle open of ali watchdog
 *	@inode: inode from VFS
 *	@file: file from VFS
 *
 *	Open the ALi watchdog device. Ensure only one person opens it
 *	at a time. Also start the watchdog running.
 */

static int ali_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */
	if (test_and_set_bit(0, &ali_is_open))
		return -EBUSY;

	/* Activate */
	ali_start();
	return nonseekable_open(inode, file);
}

/*
 *	ali_release	-	close an ALi watchdog
 *	@inode: inode from VFS
 *	@file: file from VFS
 *
 *	Close the ALi watchdog device. Actual shutdown of the timer
 *	only occurs if the magic sequence has been set.
 */

static int ali_release(struct inode *inode, struct file *file)
{
	/*
	 *      Shut off the timer.
	 */
	if (ali_expect_release == 42)
		ali_stop();
	else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		ali_keepalive();
	}
	clear_bit(0, &ali_is_open);
	ali_expect_release = 0;
	return 0;
}

/*
 *	ali_notify_sys	-	System down notifier
 *
 *	Notifier for system down
 */


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

/*
 *	Data for PCI driver interface
 *
 *	This data only exists for exporting the supported
 *	PCI ids via MODULE_DEVICE_TABLE.  We do not actually
 *	register a pci_driver, because someone else might one day
 *	want to register another driver on the same PCI id.
 */

static DEFINE_PCI_DEVICE_TABLE(ali_pci_tbl) __used = {
	{ PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},
	{ PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},
	{ 0, },
};
MODULE_DEVICE_TABLE(pci, ali_pci_tbl);

/*
 *	ali_find_watchdog	-	find a 1535 and 7101
 *
 *	Scans the PCI hardware for a 1535 series bridge and matching 7101
 *	watchdog device. This may be overtight but it is better to be safe
 */

static int __init ali_find_watchdog(void)
{
	struct pci_dev *pdev;
	u32 wdog;

	/* Check for a 1533/1535 series bridge */
	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
	if (pdev == NULL)
		pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);
	if (pdev == NULL)
		return -ENODEV;
	pci_dev_put(pdev);

	/* Check for the a 7101 PMU */
	pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
	if (pdev == NULL)
		return -ENODEV;

	if (pci_enable_device(pdev)) {
		pci_dev_put(pdev);
		return -EIO;
	}

	ali_pci = pdev;

	/*
	 *	Initialize the timer bits
	 */
	pci_read_config_dword(pdev, 0xCC, &wdog);

	/* Timer bits */
	wdog &= ~0x3F;
	/* Issued events */
	wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));
	/* No monitor bits */
	wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));

	pci_write_config_dword(pdev, 0xCC, wdog);

	return 0;
}

/*
 *	Kernel Interfaces
 */

static const struct file_operations ali_fops = {
	.owner		=	THIS_MODULE,
	.llseek		=	no_llseek,
	.write		=	ali_write,
	.unlocked_ioctl =	ali_ioctl,
	.open		=	ali_open,
	.release	=	ali_release,
};

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

static struct notifier_block ali_notifier = {
	.notifier_call =	ali_notify_sys,
};

/*
 *	watchdog_init	-	module initialiser
 *
 *	Scan for a suitable watchdog and if so initialize it. Return an error
 *	if we cannot, the error causes the module to unload
 */

static int __init watchdog_init(void)
{
	int ret;

	/* Check whether or not the hardware watchdog is there */
	if (ali_find_watchdog() != 0)
		return -ENODEV;

	/* Check that the timeout value is within it's range;
	   if not reset to the default */
	if (timeout < 1 || timeout >= 18000) {
		timeout = WATCHDOG_TIMEOUT;
		pr_info("timeout value must be 0 < timeout < 18000, using %d\n",
			timeout);
	}

	/* Calculate the watchdog's timeout */
	ali_settimer(timeout);

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

	ret = misc_register(&ali_miscdev);
	if (ret != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto unreg_reboot;
	}

	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);

out:
	return ret;
unreg_reboot:
	unregister_reboot_notifier(&ali_notifier);
	goto out;
}

/*
 *	watchdog_exit	-	module de-initialiser
 *
 *	Called while unloading a successfully installed watchdog module.
 */

static void __exit watchdog_exit(void)
{
	/* Stop the timer before we leave */
	ali_stop();

	/* Deregister */
	misc_deregister(&ali_miscdev);
	unregister_reboot_notifier(&ali_notifier);
	pci_dev_put(ali_pci);
}

module_init(watchdog_init);
module_exit(watchdog_exit);

MODULE_AUTHOR("Alan Cox");
MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);