aboutsummaryrefslogtreecommitdiff
path: root/drivers/hwmon/sch56xx-common.c
blob: 68c350c704fba85ff517f0d5f726ed53d367e45d (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
/***************************************************************************
 *   Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com>           *
 *                                                                         *
 *   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.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include "sch56xx-common.h"

/* Insmod parameters */
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

#define SIO_SCH56XX_LD_EM	0x0C	/* Embedded uController Logical Dev */
#define SIO_UNLOCK_KEY		0x55	/* Key to enable Super-I/O */
#define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */

#define SIO_REG_LDSEL		0x07	/* Logical device select */
#define SIO_REG_DEVID		0x20	/* Device ID */
#define SIO_REG_ENABLE		0x30	/* Logical device enable */
#define SIO_REG_ADDR		0x66	/* Logical device address (2 bytes) */

#define SIO_SCH5627_ID		0xC6	/* Chipset ID */
#define SIO_SCH5636_ID		0xC7	/* Chipset ID */

#define REGION_LENGTH		10

#define SCH56XX_CMD_READ	0x02
#define SCH56XX_CMD_WRITE	0x03

/* Watchdog registers */
#define SCH56XX_REG_WDOG_PRESET		0x58B
#define SCH56XX_REG_WDOG_CONTROL	0x58C
#define SCH56XX_WDOG_TIME_BASE_SEC	0x01
#define SCH56XX_REG_WDOG_OUTPUT_ENABLE	0x58E
#define SCH56XX_WDOG_OUTPUT_ENABLE	0x02

struct sch56xx_watchdog_data {
	u16 addr;
	struct mutex *io_lock;
	struct watchdog_info wdinfo;
	struct watchdog_device wddev;
	u8 watchdog_preset;
	u8 watchdog_control;
	u8 watchdog_output_enable;
};

static struct platform_device *sch56xx_pdev;

/* Super I/O functions */
static inline int superio_inb(int base, int reg)
{
	outb(reg, base);
	return inb(base + 1);
}

static inline int superio_enter(int base)
{
	/* Don't step on other drivers' I/O space by accident */
	if (!request_muxed_region(base, 2, "sch56xx")) {
		pr_err("I/O address 0x%04x already in use\n", base);
		return -EBUSY;
	}

	outb(SIO_UNLOCK_KEY, base);

	return 0;
}

static inline void superio_select(int base, int ld)
{
	outb(SIO_REG_LDSEL, base);
	outb(ld, base + 1);
}

static inline void superio_exit(int base)
{
	outb(SIO_LOCK_KEY, base);
	release_region(base, 2);
}

static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
{
	u8 val;
	int i;
	/*
	 * According to SMSC for the commands we use the maximum time for
	 * the EM to respond is 15 ms, but testing shows in practice it
	 * responds within 15-32 reads, so we first busy poll, and if
	 * that fails sleep a bit and try again until we are way past
	 * the 15 ms maximum response time.
	 */
	const int max_busy_polls = 64;
	const int max_lazy_polls = 32;

	/* (Optional) Write-Clear the EC to Host Mailbox Register */
	val = inb(addr + 1);
	outb(val, addr + 1);

	/* Set Mailbox Address Pointer to first location in Region 1 */
	outb(0x00, addr + 2);
	outb(0x80, addr + 3);

	/* Write Request Packet Header */
	outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
	outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
	outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */

	/* Write Value field */
	if (cmd == SCH56XX_CMD_WRITE)
		outb(v, addr + 4);

	/* Write Address field */
	outb(reg & 0xff, addr + 6);
	outb(reg >> 8, addr + 7);

	/* Execute the Random Access Command */
	outb(0x01, addr); /* Write 01h to the Host-to-EC register */

	/* EM Interface Polling "Algorithm" */
	for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
		if (i >= max_busy_polls)
			msleep(1);
		/* Read Interrupt source Register */
		val = inb(addr + 8);
		/* Write Clear the interrupt source bits */
		if (val)
			outb(val, addr + 8);
		/* Command Completed ? */
		if (val & 0x01)
			break;
	}
	if (i == max_busy_polls + max_lazy_polls) {
		pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
		       reg, 1);
		return -EIO;
	}

	/*
	 * According to SMSC we may need to retry this, but sofar I've always
	 * seen this succeed in 1 try.
	 */
	for (i = 0; i < max_busy_polls; i++) {
		/* Read EC-to-Host Register */
		val = inb(addr + 1);
		/* Command Completed ? */
		if (val == 0x01)
			break;

		if (i == 0)
			pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
				(unsigned int)val, reg);
	}
	if (i == max_busy_polls) {
		pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
		       reg, 2);
		return -EIO;
	}

	/*
	 * According to the SMSC app note we should now do:
	 *
	 * Set Mailbox Address Pointer to first location in Region 1 *
	 * outb(0x00, addr + 2);
	 * outb(0x80, addr + 3);
	 *
	 * But if we do that things don't work, so let's not.
	 */

	/* Read Value field */
	if (cmd == SCH56XX_CMD_READ)
		return inb(addr + 4);

	return 0;
}

int sch56xx_read_virtual_reg(u16 addr, u16 reg)
{
	return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg);

int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
{
	return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
}
EXPORT_SYMBOL(sch56xx_write_virtual_reg);

int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
{
	int lsb, msb;

	/* Read LSB first, this will cause the matching MSB to be latched */
	lsb = sch56xx_read_virtual_reg(addr, reg);
	if (lsb < 0)
		return lsb;

	msb = sch56xx_read_virtual_reg(addr, reg + 1);
	if (msb < 0)
		return msb;

	return lsb | (msb << 8);
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg16);

int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
			       int high_nibble)
{
	int msb, lsn;

	/* Read MSB first, this will cause the matching LSN to be latched */
	msb = sch56xx_read_virtual_reg(addr, msb_reg);
	if (msb < 0)
		return msb;

	lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
	if (lsn < 0)
		return lsn;

	if (high_nibble)
		return (msb << 4) | (lsn >> 4);
	else
		return (msb << 4) | (lsn & 0x0f);
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg12);

/*
 * Watchdog routines
 */

static int watchdog_set_timeout(struct watchdog_device *wddev,
				unsigned int timeout)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	unsigned int resolution;
	u8 control;
	int ret;

	/* 1 second or 60 second resolution? */
	if (timeout <= 255)
		resolution = 1;
	else
		resolution = 60;

	if (timeout < resolution || timeout > (resolution * 255))
		return -EINVAL;

	if (resolution == 1)
		control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
	else
		control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;

	if (data->watchdog_control != control) {
		mutex_lock(data->io_lock);
		ret = sch56xx_write_virtual_reg(data->addr,
						SCH56XX_REG_WDOG_CONTROL,
						control);
		mutex_unlock(data->io_lock);
		if (ret)
			return ret;

		data->watchdog_control = control;
	}

	/*
	 * Remember new timeout value, but do not write as that (re)starts
	 * the watchdog countdown.
	 */
	data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
	wddev->timeout = data->watchdog_preset * resolution;

	return 0;
}

static int watchdog_start(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret;
	u8 val;

	/*
	 * The sch56xx's watchdog cannot really be started / stopped
	 * it is always running, but we can avoid the timer expiring
	 * from causing a system reset by clearing the output enable bit.
	 *
	 * The sch56xx's watchdog will set the watchdog event bit, bit 0
	 * of the second interrupt source register (at base-address + 9),
	 * when the timer expires.
	 *
	 * This will only cause a system reset if the 0-1 flank happens when
	 * output enable is true. Setting output enable after the flank will
	 * not cause a reset, nor will the timer expiring a second time.
	 * This means we must clear the watchdog event bit in case it is set.
	 *
	 * The timer may still be running (after a recent watchdog_stop) and
	 * mere milliseconds away from expiring, so the timer must be reset
	 * first!
	 */

	mutex_lock(data->io_lock);

	/* 1. Reset the watchdog countdown counter */
	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
					data->watchdog_preset);
	if (ret)
		goto leave;

	/* 2. Enable output */
	val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
	ret = sch56xx_write_virtual_reg(data->addr,
					SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
	if (ret)
		goto leave;

	data->watchdog_output_enable = val;

	/* 3. Clear the watchdog event bit if set */
	val = inb(data->addr + 9);
	if (val & 0x01)
		outb(0x01, data->addr + 9);

leave:
	mutex_unlock(data->io_lock);
	return ret;
}

static int watchdog_trigger(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret;

	/* Reset the watchdog countdown counter */
	mutex_lock(data->io_lock);
	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
					data->watchdog_preset);
	mutex_unlock(data->io_lock);

	return ret;
}

static int watchdog_stop(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret = 0;
	u8 val;

	val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
	mutex_lock(data->io_lock);
	ret = sch56xx_write_virtual_reg(data->addr,
					SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
	mutex_unlock(data->io_lock);
	if (ret)
		return ret;

	data->watchdog_output_enable = val;
	return 0;
}

static const struct watchdog_ops watchdog_ops = {
	.owner		= THIS_MODULE,
	.start		= watchdog_start,
	.stop		= watchdog_stop,
	.ping		= watchdog_trigger,
	.set_timeout	= watchdog_set_timeout,
};

struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent,
	u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
{
	struct sch56xx_watchdog_data *data;
	int err, control, output_enable;

	/* Cache the watchdog registers */
	mutex_lock(io_lock);
	control =
		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
	output_enable =
		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
	mutex_unlock(io_lock);

	if (control < 0)
		return NULL;
	if (output_enable < 0)
		return NULL;
	if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
		pr_warn("Watchdog not enabled by BIOS, not registering\n");
		return NULL;
	}

	data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
	if (!data)
		return NULL;

	data->addr = addr;
	data->io_lock = io_lock;

	strlcpy(data->wdinfo.identity, "sch56xx watchdog",
		sizeof(data->wdinfo.identity));
	data->wdinfo.firmware_version = revision;
	data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
	if (!nowayout)
		data->wdinfo.options |= WDIOF_MAGICCLOSE;

	data->wddev.info = &data->wdinfo;
	data->wddev.ops = &watchdog_ops;
	data->wddev.parent = parent;
	data->wddev.timeout = 60;
	data->wddev.min_timeout = 1;
	data->wddev.max_timeout = 255 * 60;
	if (nowayout)
		set_bit(WDOG_NO_WAY_OUT, &data->wddev.status);
	if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
		set_bit(WDOG_ACTIVE, &data->wddev.status);

	/* Since the watchdog uses a downcounter there is no register to read
	   the BIOS set timeout from (if any was set at all) ->
	   Choose a preset which will give us a 1 minute timeout */
	if (control & SCH56XX_WDOG_TIME_BASE_SEC)
		data->watchdog_preset = 60; /* seconds */
	else
		data->watchdog_preset = 1; /* minute */

	data->watchdog_control = control;
	data->watchdog_output_enable = output_enable;

	watchdog_set_drvdata(&data->wddev, data);
	err = watchdog_register_device(&data->wddev);
	if (err) {
		pr_err("Registering watchdog chardev: %d\n", err);
		kfree(data);
		return NULL;
	}

	return data;
}
EXPORT_SYMBOL(sch56xx_watchdog_register);

void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
{
	watchdog_unregister_device(&data->wddev);
	kfree(data);
}
EXPORT_SYMBOL(sch56xx_watchdog_unregister);

/*
 * platform dev find, add and remove functions
 */

static int __init sch56xx_find(int sioaddr, const char **name)
{
	u8 devid;
	unsigned short address;
	int err;

	err = superio_enter(sioaddr);
	if (err)
		return err;

	devid = superio_inb(sioaddr, SIO_REG_DEVID);
	switch (devid) {
	case SIO_SCH5627_ID:
		*name = "sch5627";
		break;
	case SIO_SCH5636_ID:
		*name = "sch5636";
		break;
	default:
		pr_debug("Unsupported device id: 0x%02x\n",
			 (unsigned int)devid);
		err = -ENODEV;
		goto exit;
	}

	superio_select(sioaddr, SIO_SCH56XX_LD_EM);

	if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
		pr_warn("Device not activated\n");
		err = -ENODEV;
		goto exit;
	}

	/*
	 * Warning the order of the low / high byte is the other way around
	 * as on most other superio devices!!
	 */
	address = superio_inb(sioaddr, SIO_REG_ADDR) |
		   superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
	if (address == 0) {
		pr_warn("Base address not set\n");
		err = -ENODEV;
		goto exit;
	}
	err = address;

exit:
	superio_exit(sioaddr);
	return err;
}

static int __init sch56xx_device_add(int address, const char *name)
{
	struct resource res = {
		.start	= address,
		.end	= address + REGION_LENGTH - 1,
		.flags	= IORESOURCE_IO,
	};
	int err;

	sch56xx_pdev = platform_device_alloc(name, address);
	if (!sch56xx_pdev)
		return -ENOMEM;

	res.name = sch56xx_pdev->name;
	err = acpi_check_resource_conflict(&res);
	if (err)
		goto exit_device_put;

	err = platform_device_add_resources(sch56xx_pdev, &res, 1);
	if (err) {
		pr_err("Device resource addition failed\n");
		goto exit_device_put;
	}

	err = platform_device_add(sch56xx_pdev);
	if (err) {
		pr_err("Device addition failed\n");
		goto exit_device_put;
	}

	return 0;

exit_device_put:
	platform_device_put(sch56xx_pdev);

	return err;
}

static int __init sch56xx_init(void)
{
	int address;
	const char *name = NULL;

	address = sch56xx_find(0x4e, &name);
	if (address < 0)
		address = sch56xx_find(0x2e, &name);
	if (address < 0)
		return address;

	return sch56xx_device_add(address, name);
}

static void __exit sch56xx_exit(void)
{
	platform_device_unregister(sch56xx_pdev);
}

MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");

module_init(sch56xx_init);
module_exit(sch56xx_exit);