summaryrefslogtreecommitdiffstats
path: root/drivers/watchdog/alim7101_wdt.c
blob: c8e3ab056767d2cac34bc89b9aca36e62fb60620 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 *	ALi M7101 PMU Computer Watchdog Timer driver
 *
 *	Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
 *	and the Cobalt kernel WDT timer driver by Tim Hockin
 *	                                      <thockin@cobaltnet.com>
 *
 *	(c)2002 Steve Hill <steve@navaho.co.uk>
 *
 *  This WDT driver is different from most other Linux WDT
 *  drivers in that the driver will ping the watchdog by itself,
 *  because this particular WDT has a very short timeout (1.6
 *  seconds) and it would be insane to count on any userspace
 *  daemon always getting scheduled within that time frame.
 *
 *  Additions:
 *   Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
 *                  found on very old cobalt hardware.
 *                  -- Mike Waychison <michael.waychison@sun.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/timer.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/io.h>
#include <linux/uaccess.h>


#define WDT_ENABLE 0x9C
#define WDT_DISABLE 0x8C

#define ALI_7101_WDT    0x92
#define ALI_7101_GPIO   0x7D
#define ALI_7101_GPIO_O 0x7E
#define ALI_WDT_ARM     0x01

/*
 * We're going to use a 1 second timeout.
 * If we reset the watchdog every ~250ms we should be safe.  */

#define WDT_INTERVAL (HZ/4+1)

/*
 * We must not require too good response from the userspace daemon.
 * Here we require the userspace daemon to send us a heartbeat
 * char to /dev/watchdog every 30 seconds.
 */

#define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
static int timeout = WATCHDOG_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		"Watchdog timeout in seconds. (1<=timeout<=3600, default="
				__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

static int use_gpio; /* Use the pic (for a1d revision alim7101) */
module_param(use_gpio, int, 0);
MODULE_PARM_DESC(use_gpio,
		"Use the gpio watchdog (required by old cobalt boards).");

static void wdt_timer_ping(struct timer_list *);
static DEFINE_TIMER(timer, wdt_timer_ping);
static unsigned long next_heartbeat;
static unsigned long wdt_is_open;
static char wdt_expect_close;
static struct pci_dev *alim7101_pmu;

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) ")");

/*
 *	Whack the dog
 */

static void wdt_timer_ping(struct timer_list *unused)
{
	/* If we got a heartbeat pulse within the WDT_US_INTERVAL
	 * we agree to ping the WDT
	 */
	char tmp;

	if (time_before(jiffies, next_heartbeat)) {
		/* Ping the WDT (this is actually a disarm/arm sequence) */
		pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp | 0x20);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp & ~0x20);
		}
	} else {
		pr_warn("Heartbeat lost! Will not ping the watchdog\n");
	}
	/* Re-set the timer interval */
	mod_timer(&timer, jiffies + WDT_INTERVAL);
}

/*
 * Utility routines
 */

static void wdt_change(int writeval)
{
	char tmp;

	pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
	if (writeval == WDT_ENABLE) {
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp | ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp & ~0x20);
		}

	} else {
		pci_write_config_byte(alim7101_pmu,
					ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
		if (use_gpio) {
			pci_read_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, &tmp);
			pci_write_config_byte(alim7101_pmu,
					ALI_7101_GPIO_O, tmp | 0x20);
		}
	}
}

static void wdt_startup(void)
{
	next_heartbeat = jiffies + (timeout * HZ);

	/* We must enable before we kick off the timer in case the timer
	   occurs as we ping it */

	wdt_change(WDT_ENABLE);

	/* Start the timer */
	mod_timer(&timer, jiffies + WDT_INTERVAL);

	pr_info("Watchdog timer is now enabled\n");
}

static void wdt_turnoff(void)
{
	/* Stop the timer */
	del_timer_sync(&timer);
	wdt_change(WDT_DISABLE);
	pr_info("Watchdog timer is now disabled...\n");
}

static void wdt_keepalive(void)
{
	/* user land ping */
	next_heartbeat = jiffies + (timeout * HZ);
}

/*
 * /dev/watchdog handling
 */

static ssize_t fop_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
			 * five months ago... */
			wdt_expect_close = 0;

			/* now scan */
			for (ofs = 0; ofs != count; ofs++) {
				char c;
				if (get_user(c, buf + ofs))
					return -EFAULT;
				if (c == 'V')
					wdt_expect_close = 42;
			}
		}
		/* someone wrote to us, we should restart timer */
		wdt_keepalive();
	}
	return count;
}

static int fop_open(struct inode *inode, struct file *file)
{
	/* Just in case we're already talking to someone... */
	if (test_and_set_bit(0, &wdt_is_open))
		return -EBUSY;
	/* Good, fire up the show */
	wdt_startup();
	return stream_open(inode, file);
}

static int fop_close(struct inode *inode, struct file *file)
{
	if (wdt_expect_close == 42)
		wdt_turnoff();
	else {
		/* wim: shouldn't there be a: del_timer(&timer); */
		pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
	}
	clear_bit(0, &wdt_is_open);
	wdt_expect_close = 0;
	return 0;
}

static long fop_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 = 1,
		.identity = "ALiM7101",
	};

	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) {
			wdt_turnoff();
			retval = 0;
		}
		if (new_options & WDIOS_ENABLECARD) {
			wdt_startup();
			retval = 0;
		}
		return retval;
	}
	case WDIOC_KEEPALIVE:
		wdt_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
	{
		int new_timeout;

		if (get_user(new_timeout, p))
			return -EFAULT;
		/* arbitrary upper limit */
		if (new_timeout < 1 || new_timeout > 3600)
			return -EINVAL;
		timeout = new_timeout;
		wdt_keepalive();
	}
		/* Fall through */
	case WDIOC_GETTIMEOUT:
		return put_user(timeout, p);
	default:
		return -ENOTTY;
	}
}

static const struct file_operations wdt_fops = {
	.owner		=	THIS_MODULE,
	.llseek		=	no_llseek,
	.write		=	fop_write,
	.open		=	fop_open,
	.release	=	fop_close,
	.unlocked_ioctl	=	fop_ioctl,
};

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

static int wdt_restart_handle(struct notifier_block *this, unsigned long mode,
			      void *cmd)
{
	/*
	 * Cobalt devices have no way of rebooting themselves other
	 * than getting the watchdog to pull reset, so we restart the
	 * watchdog on reboot with no heartbeat.
	 */
	wdt_change(WDT_ENABLE);

	/* loop until the watchdog fires */
	while (true)
		;

	return NOTIFY_DONE;
}

static struct notifier_block wdt_restart_handler = {
	.notifier_call = wdt_restart_handle,
	.priority = 128,
};

/*
 *	Notifier for system down
 */

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

	return NOTIFY_DONE;
}

/*
 *	The WDT needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */

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

static void __exit alim7101_wdt_unload(void)
{
	wdt_turnoff();
	/* Deregister */
	misc_deregister(&wdt_miscdev);
	unregister_reboot_notifier(&wdt_notifier);
	unregister_restart_handler(&wdt_restart_handler);
	pci_dev_put(alim7101_pmu);
}

static int __init alim7101_wdt_init(void)
{
	int rc = -EBUSY;
	struct pci_dev *ali1543_south;
	char tmp;

	pr_info("Steve Hill <steve@navaho.co.uk>\n");
	alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
		NULL);
	if (!alim7101_pmu) {
		pr_info("ALi M7101 PMU not present - WDT not set\n");
		return -EBUSY;
	}

	/* Set the WDT in the PMU to 1 second */
	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);

	ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
		NULL);
	if (!ali1543_south) {
		pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
		goto err_out;
	}
	pci_read_config_byte(ali1543_south, 0x5e, &tmp);
	pci_dev_put(ali1543_south);
	if ((tmp & 0x1e) == 0x00) {
		if (!use_gpio) {
			pr_info("Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
			goto err_out;
		}
		nowayout = 1;
	} else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
		pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
		goto err_out;
	}

	if (timeout < 1 || timeout > 3600) {
		/* arbitrary upper limit */
		timeout = WATCHDOG_TIMEOUT;
		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
			timeout);
	}

	rc = register_reboot_notifier(&wdt_notifier);
	if (rc) {
		pr_err("cannot register reboot notifier (err=%d)\n", rc);
		goto err_out;
	}

	rc = register_restart_handler(&wdt_restart_handler);
	if (rc) {
		pr_err("cannot register restart handler (err=%d)\n", rc);
		goto err_out_reboot;
	}

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

	if (nowayout)
		__module_get(THIS_MODULE);

	pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);
	return 0;

err_out_restart:
	unregister_restart_handler(&wdt_restart_handler);
err_out_reboot:
	unregister_reboot_notifier(&wdt_notifier);
err_out:
	pci_dev_put(alim7101_pmu);
	return rc;
}

module_init(alim7101_wdt_init);
module_exit(alim7101_wdt_unload);

static const struct pci_device_id alim7101_pci_tbl[] __used = {
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
	{ PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
	{ }
};

MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);

MODULE_AUTHOR("Steve Hill");
MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud