Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  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
/*
 *	nv_tco 0.01:	TCO timer driver for NV chipsets
 *
 *	(c) Copyright 2005 Google Inc., All Rights Reserved.
 *
 *	Based off i8xx_tco.c:
 *	(c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights
 *	Reserved.
 *				http://www.kernelconcepts.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.
 *
 *	TCO timer driver for NV chipsets
 *	based on softdog.c by Alan Cox <alan@redhat.com>
 */

/*
 *	Includes, defines, variables, module parameters, ...
 */

#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/init.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/platform_device.h>
#include <linux/uaccess.h>
#include <linux/io.h>

#include "nv_tco.h"

/* Module and version information */
#define TCO_VERSION "0.01"
#define TCO_MODULE_NAME "NV_TCO"
#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION

/* internal variables */
static unsigned int tcobase;
static DEFINE_SPINLOCK(tco_lock);	/* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *tco_pci;

/* the watchdog platform device */
static struct platform_device *nv_tco_platform_device;

/* module parameters */
#define WATCHDOG_HEARTBEAT 30	/* 30 sec default heartbeat (2<heartbeat<39) */
static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
			    "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");

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) ")");

/*
 * Some TCO specific functions
 */
static inline unsigned char seconds_to_ticks(int seconds)
{
	/* the internal timer is stored as ticks which decrement
	 * every 0.6 seconds */
	return (seconds * 10) / 6;
}

static void tco_timer_start(void)
{
	u32 val;
	unsigned long flags;

	spin_lock_irqsave(&tco_lock, flags);
	val = inl(TCO_CNT(tcobase));
	val &= ~TCO_CNT_TCOHALT;
	outl(val, TCO_CNT(tcobase));
	spin_unlock_irqrestore(&tco_lock, flags);
}

static void tco_timer_stop(void)
{
	u32 val;
	unsigned long flags;

	spin_lock_irqsave(&tco_lock, flags);
	val = inl(TCO_CNT(tcobase));
	val |= TCO_CNT_TCOHALT;
	outl(val, TCO_CNT(tcobase));
	spin_unlock_irqrestore(&tco_lock, flags);
}

static void tco_timer_keepalive(void)
{
	unsigned long flags;

	spin_lock_irqsave(&tco_lock, flags);
	outb(0x01, TCO_RLD(tcobase));
	spin_unlock_irqrestore(&tco_lock, flags);
}

static int tco_timer_set_heartbeat(int t)
{
	int ret = 0;
	unsigned char tmrval;
	unsigned long flags;
	u8 val;

	/*
	 * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
	 * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
	 * out of range on it's own (to avoid overflow in tmrval).
	 */
	if (t < 0 || t > 0x3f)
		return -EINVAL;
	tmrval = seconds_to_ticks(t);

	/* "Values of 0h-3h are ignored and should not be attempted" */
	if (tmrval > 0x3f || tmrval < 0x04)
		return -EINVAL;

	/* Write new heartbeat to watchdog */
	spin_lock_irqsave(&tco_lock, flags);
	val = inb(TCO_TMR(tcobase));
	val &= 0xc0;
	val |= tmrval;
	outb(val, TCO_TMR(tcobase));
	val = inb(TCO_TMR(tcobase));

	if ((val & 0x3f) != tmrval)
		ret = -EINVAL;
	spin_unlock_irqrestore(&tco_lock, flags);

	if (ret)
		return ret;

	heartbeat = t;
	return 0;
}

/*
 *	/dev/watchdog handling
 */

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

	/* Reload and activate timer */
	tco_timer_keepalive();
	tco_timer_start();
	return nonseekable_open(inode, file);
}

static int nv_tco_release(struct inode *inode, struct file *file)
{
	/* Shut off the timer */
	if (tco_expect_close == 42) {
		tco_timer_stop();
	} else {
		pr_crit("Unexpected close, not stopping watchdog!\n");
		tco_timer_keepalive();
	}
	clear_bit(0, &timer_alive);
	tco_expect_close = 0;
	return 0;
}

static ssize_t nv_tco_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...
			 */
			tco_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')
					tco_expect_close = 42;
			}
		}

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

static long nv_tco_ioctl(struct file *file, unsigned int cmd,
			 unsigned long arg)
{
	int new_options, retval = -EINVAL;
	int new_heartbeat;
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	static const struct watchdog_info ident = {
		.options =		WDIOF_SETTIMEOUT |
					WDIOF_KEEPALIVEPING |
					WDIOF_MAGICCLOSE,
		.firmware_version =	0,
		.identity =		TCO_MODULE_NAME,
	};

	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:
		if (get_user(new_options, p))
			return -EFAULT;
		if (new_options & WDIOS_DISABLECARD) {
			tco_timer_stop();
			retval = 0;
		}
		if (new_options & WDIOS_ENABLECARD) {
			tco_timer_keepalive();
			tco_timer_start();
			retval = 0;
		}
		return retval;
	case WDIOC_KEEPALIVE:
		tco_timer_keepalive();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_heartbeat, p))
			return -EFAULT;
		if (tco_timer_set_heartbeat(new_heartbeat))
			return -EINVAL;
		tco_timer_keepalive();
		/* Fall through */
	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, p);
	default:
		return -ENOTTY;
	}
}

/*
 *	Kernel Interfaces
 */

static const struct file_operations nv_tco_fops = {
	.owner =		THIS_MODULE,
	.llseek =		no_llseek,
	.write =		nv_tco_write,
	.unlocked_ioctl =	nv_tco_ioctl,
	.open =			nv_tco_open,
	.release =		nv_tco_release,
};

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

/*
 * 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 const struct pci_device_id tco_pci_tbl[] = {
	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
	  PCI_ANY_ID, PCI_ANY_ID, },
	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
	  PCI_ANY_ID, PCI_ANY_ID, },
	{ 0, },			/* End of list */
};
MODULE_DEVICE_TABLE(pci, tco_pci_tbl);

/*
 *	Init & exit routines
 */

static unsigned char nv_tco_getdevice(void)
{
	struct pci_dev *dev = NULL;
	u32 val;

	/* Find the PCI device */
	for_each_pci_dev(dev) {
		if (pci_match_id(tco_pci_tbl, dev) != NULL) {
			tco_pci = dev;
			break;
		}
	}

	if (!tco_pci)
		return 0;

	/* Find the base io port */
	pci_read_config_dword(tco_pci, 0x64, &val);
	val &= 0xffff;
	if (val == 0x0001 || val == 0x0000) {
		/* Something is wrong here, bar isn't setup */
		pr_err("failed to get tcobase address\n");
		return 0;
	}
	val &= 0xff00;
	tcobase = val + 0x40;

	if (!request_region(tcobase, 0x10, "NV TCO")) {
		pr_err("I/O address 0x%04x already in use\n", tcobase);
		return 0;
	}

	/* Set a reasonable heartbeat before we stop the timer */
	tco_timer_set_heartbeat(30);

	/*
	 * Stop the TCO before we change anything so we don't race with
	 * a zeroed timer.
	 */
	tco_timer_keepalive();
	tco_timer_stop();

	/* Disable SMI caused by TCO */
	if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
		pr_err("I/O address 0x%04x already in use\n",
		       MCP51_SMI_EN(tcobase));
		goto out;
	}
	val = inl(MCP51_SMI_EN(tcobase));
	val &= ~MCP51_SMI_EN_TCO;
	outl(val, MCP51_SMI_EN(tcobase));
	val = inl(MCP51_SMI_EN(tcobase));
	release_region(MCP51_SMI_EN(tcobase), 4);
	if (val & MCP51_SMI_EN_TCO) {
		pr_err("Could not disable SMI caused by TCO\n");
		goto out;
	}

	/* Check chipset's NO_REBOOT bit */
	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
	val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
	if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
		pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n");
		goto out;
	}

	return 1;
out:
	release_region(tcobase, 0x10);
	return 0;
}

static int nv_tco_init(struct platform_device *dev)
{
	int ret;

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

	/* Check to see if last reboot was due to watchdog timeout */
	pr_info("Watchdog reboot %sdetected\n",
		inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");

	/* Clear out the old status */
	outl(TCO_STS_RESET, TCO_STS(tcobase));

	/*
	 * Check that the heartbeat value is within it's range.
	 * If not, reset to the default.
	 */
	if (tco_timer_set_heartbeat(heartbeat)) {
		heartbeat = WATCHDOG_HEARTBEAT;
		tco_timer_set_heartbeat(heartbeat);
		pr_info("heartbeat value must be 2<heartbeat<39, using %d\n",
			heartbeat);
	}

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

	clear_bit(0, &timer_alive);

	tco_timer_stop();

	pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n",
		tcobase, heartbeat, nowayout);

	return 0;

unreg_region:
	release_region(tcobase, 0x10);
	return ret;
}

static void nv_tco_cleanup(void)
{
	u32 val;

	/* Stop the timer before we leave */
	if (!nowayout)
		tco_timer_stop();

	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
	val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
	if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
		pr_crit("Couldn't unset REBOOT bit.  Machine may soon reset\n");
	}

	/* Deregister */
	misc_deregister(&nv_tco_miscdev);
	release_region(tcobase, 0x10);
}

static int nv_tco_remove(struct platform_device *dev)
{
	if (tcobase)
		nv_tco_cleanup();

	return 0;
}

static void nv_tco_shutdown(struct platform_device *dev)
{
	u32 val;

	tco_timer_stop();

	/* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not
	 * unset during shutdown. */
	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
	val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
}

static struct platform_driver nv_tco_driver = {
	.probe		= nv_tco_init,
	.remove		= nv_tco_remove,
	.shutdown	= nv_tco_shutdown,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= TCO_MODULE_NAME,
	},
};

static int __init nv_tco_init_module(void)
{
	int err;

	pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION);

	err = platform_driver_register(&nv_tco_driver);
	if (err)
		return err;

	nv_tco_platform_device = platform_device_register_simple(
					TCO_MODULE_NAME, -1, NULL, 0);
	if (IS_ERR(nv_tco_platform_device)) {
		err = PTR_ERR(nv_tco_platform_device);
		goto unreg_platform_driver;
	}

	return 0;

unreg_platform_driver:
	platform_driver_unregister(&nv_tco_driver);
	return err;
}

static void __exit nv_tco_cleanup_module(void)
{
	platform_device_unregister(nv_tco_platform_device);
	platform_driver_unregister(&nv_tco_driver);
	pr_info("NV TCO Watchdog Module Unloaded\n");
}

module_init(nv_tco_init_module);
module_exit(nv_tco_cleanup_module);

MODULE_AUTHOR("Mike Waychison");
MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
MODULE_LICENSE("GPL");