sch56xx-common.c revision fb551405c0f8e15d6fc7ae6e16a5e15382f8b8ac 
1/***************************************************************************
2 *   Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com>           *
3 *                                                                         *
4 *   This program is free software; you can redistribute it and/or modify  *
5 *   it under the terms of the GNU General Public License as published by  *
6 *   the Free Software Foundation; either version 2 of the License, or     *
7 *   (at your option) any later version.                                   *
8 *                                                                         *
9 *   This program is distributed in the hope that it will be useful,       *
10 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
11 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
12 *   GNU General Public License for more details.                          *
13 *                                                                         *
14 *   You should have received a copy of the GNU General Public License     *
15 *   along with this program; if not, write to the                         *
16 *   Free Software Foundation, Inc.,                                       *
17 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
18 ***************************************************************************/
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/module.h>
23#include <linux/init.h>
24#include <linux/platform_device.h>
25#include <linux/err.h>
26#include <linux/io.h>
27#include <linux/acpi.h>
28#include <linux/delay.h>
29#include <linux/fs.h>
30#include <linux/watchdog.h>
31#include <linux/miscdevice.h>
32#include <linux/uaccess.h>
33#include <linux/kref.h>
34#include <linux/slab.h>
35#include "sch56xx-common.h"
36
37/* Insmod parameters */
38static int nowayout = WATCHDOG_NOWAYOUT;
39module_param(nowayout, int, 0);
40MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
41	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42
43#define SIO_SCH56XX_LD_EM	0x0C	/* Embedded uController Logical Dev */
44#define SIO_UNLOCK_KEY		0x55	/* Key to enable Super-I/O */
45#define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
46
47#define SIO_REG_LDSEL		0x07	/* Logical device select */
48#define SIO_REG_DEVID		0x20	/* Device ID */
49#define SIO_REG_ENABLE		0x30	/* Logical device enable */
50#define SIO_REG_ADDR		0x66	/* Logical device address (2 bytes) */
51
52#define SIO_SCH5627_ID		0xC6	/* Chipset ID */
53#define SIO_SCH5636_ID		0xC7	/* Chipset ID */
54
55#define REGION_LENGTH		10
56
57#define SCH56XX_CMD_READ	0x02
58#define SCH56XX_CMD_WRITE	0x03
59
60/* Watchdog registers */
61#define SCH56XX_REG_WDOG_PRESET		0x58B
62#define SCH56XX_REG_WDOG_CONTROL	0x58C
63#define SCH56XX_WDOG_TIME_BASE_SEC	0x01
64#define SCH56XX_REG_WDOG_OUTPUT_ENABLE	0x58E
65#define SCH56XX_WDOG_OUTPUT_ENABLE	0x02
66
67struct sch56xx_watchdog_data {
68	u16 addr;
69	struct mutex *io_lock;
70	struct watchdog_info wdinfo;
71	struct watchdog_device wddev;
72	u8 watchdog_preset;
73	u8 watchdog_control;
74	u8 watchdog_output_enable;
75};
76
77static struct platform_device *sch56xx_pdev;
78
79/* Super I/O functions */
80static inline int superio_inb(int base, int reg)
81{
82	outb(reg, base);
83	return inb(base + 1);
84}
85
86static inline int superio_enter(int base)
87{
88	/* Don't step on other drivers' I/O space by accident */
89	if (!request_muxed_region(base, 2, "sch56xx")) {
90		pr_err("I/O address 0x%04x already in use\n", base);
91		return -EBUSY;
92	}
93
94	outb(SIO_UNLOCK_KEY, base);
95
96	return 0;
97}
98
99static inline void superio_select(int base, int ld)
100{
101	outb(SIO_REG_LDSEL, base);
102	outb(ld, base + 1);
103}
104
105static inline void superio_exit(int base)
106{
107	outb(SIO_LOCK_KEY, base);
108	release_region(base, 2);
109}
110
111static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
112{
113	u8 val;
114	int i;
115	/*
116	 * According to SMSC for the commands we use the maximum time for
117	 * the EM to respond is 15 ms, but testing shows in practice it
118	 * responds within 15-32 reads, so we first busy poll, and if
119	 * that fails sleep a bit and try again until we are way past
120	 * the 15 ms maximum response time.
121	 */
122	const int max_busy_polls = 64;
123	const int max_lazy_polls = 32;
124
125	/* (Optional) Write-Clear the EC to Host Mailbox Register */
126	val = inb(addr + 1);
127	outb(val, addr + 1);
128
129	/* Set Mailbox Address Pointer to first location in Region 1 */
130	outb(0x00, addr + 2);
131	outb(0x80, addr + 3);
132
133	/* Write Request Packet Header */
134	outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
135	outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
136	outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
137
138	/* Write Value field */
139	if (cmd == SCH56XX_CMD_WRITE)
140		outb(v, addr + 4);
141
142	/* Write Address field */
143	outb(reg & 0xff, addr + 6);
144	outb(reg >> 8, addr + 7);
145
146	/* Execute the Random Access Command */
147	outb(0x01, addr); /* Write 01h to the Host-to-EC register */
148
149	/* EM Interface Polling "Algorithm" */
150	for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
151		if (i >= max_busy_polls)
152			msleep(1);
153		/* Read Interrupt source Register */
154		val = inb(addr + 8);
155		/* Write Clear the interrupt source bits */
156		if (val)
157			outb(val, addr + 8);
158		/* Command Completed ? */
159		if (val & 0x01)
160			break;
161	}
162	if (i == max_busy_polls + max_lazy_polls) {
163		pr_err("Max retries exceeded reading virtual "
164		       "register 0x%04hx (%d)\n", reg, 1);
165		return -EIO;
166	}
167
168	/*
169	 * According to SMSC we may need to retry this, but sofar I've always
170	 * seen this succeed in 1 try.
171	 */
172	for (i = 0; i < max_busy_polls; i++) {
173		/* Read EC-to-Host Register */
174		val = inb(addr + 1);
175		/* Command Completed ? */
176		if (val == 0x01)
177			break;
178
179		if (i == 0)
180			pr_warn("EC reports: 0x%02x reading virtual register "
181				"0x%04hx\n", (unsigned int)val, reg);
182	}
183	if (i == max_busy_polls) {
184		pr_err("Max retries exceeded reading virtual "
185		       "register 0x%04hx (%d)\n", reg, 2);
186		return -EIO;
187	}
188
189	/*
190	 * According to the SMSC app note we should now do:
191	 *
192	 * Set Mailbox Address Pointer to first location in Region 1 *
193	 * outb(0x00, addr + 2);
194	 * outb(0x80, addr + 3);
195	 *
196	 * But if we do that things don't work, so let's not.
197	 */
198
199	/* Read Value field */
200	if (cmd == SCH56XX_CMD_READ)
201		return inb(addr + 4);
202
203	return 0;
204}
205
206int sch56xx_read_virtual_reg(u16 addr, u16 reg)
207{
208	return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
209}
210EXPORT_SYMBOL(sch56xx_read_virtual_reg);
211
212int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
213{
214	return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
215}
216EXPORT_SYMBOL(sch56xx_write_virtual_reg);
217
218int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
219{
220	int lsb, msb;
221
222	/* Read LSB first, this will cause the matching MSB to be latched */
223	lsb = sch56xx_read_virtual_reg(addr, reg);
224	if (lsb < 0)
225		return lsb;
226
227	msb = sch56xx_read_virtual_reg(addr, reg + 1);
228	if (msb < 0)
229		return msb;
230
231	return lsb | (msb << 8);
232}
233EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
234
235int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
236			       int high_nibble)
237{
238	int msb, lsn;
239
240	/* Read MSB first, this will cause the matching LSN to be latched */
241	msb = sch56xx_read_virtual_reg(addr, msb_reg);
242	if (msb < 0)
243		return msb;
244
245	lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
246	if (lsn < 0)
247		return lsn;
248
249	if (high_nibble)
250		return (msb << 4) | (lsn >> 4);
251	else
252		return (msb << 4) | (lsn & 0x0f);
253}
254EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
255
256/*
257 * Watchdog routines
258 */
259
260static int watchdog_set_timeout(struct watchdog_device *wddev,
261				unsigned int timeout)
262{
263	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
264	unsigned int resolution;
265	u8 control;
266	int ret;
267
268	/* 1 second or 60 second resolution? */
269	if (timeout <= 255)
270		resolution = 1;
271	else
272		resolution = 60;
273
274	if (timeout < resolution || timeout > (resolution * 255))
275		return -EINVAL;
276
277	if (resolution == 1)
278		control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
279	else
280		control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
281
282	if (data->watchdog_control != control) {
283		mutex_lock(data->io_lock);
284		ret = sch56xx_write_virtual_reg(data->addr,
285						SCH56XX_REG_WDOG_CONTROL,
286						control);
287		mutex_unlock(data->io_lock);
288		if (ret)
289			return ret;
290
291		data->watchdog_control = control;
292	}
293
294	/*
295	 * Remember new timeout value, but do not write as that (re)starts
296	 * the watchdog countdown.
297	 */
298	data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
299	wddev->timeout = data->watchdog_preset * resolution;
300
301	return 0;
302}
303
304static int watchdog_start(struct watchdog_device *wddev)
305{
306	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
307	int ret;
308	u8 val;
309
310	/*
311	 * The sch56xx's watchdog cannot really be started / stopped
312	 * it is always running, but we can avoid the timer expiring
313	 * from causing a system reset by clearing the output enable bit.
314	 *
315	 * The sch56xx's watchdog will set the watchdog event bit, bit 0
316	 * of the second interrupt source register (at base-address + 9),
317	 * when the timer expires.
318	 *
319	 * This will only cause a system reset if the 0-1 flank happens when
320	 * output enable is true. Setting output enable after the flank will
321	 * not cause a reset, nor will the timer expiring a second time.
322	 * This means we must clear the watchdog event bit in case it is set.
323	 *
324	 * The timer may still be running (after a recent watchdog_stop) and
325	 * mere milliseconds away from expiring, so the timer must be reset
326	 * first!
327	 */
328
329	mutex_lock(data->io_lock);
330
331	/* 1. Reset the watchdog countdown counter */
332	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
333					data->watchdog_preset);
334	if (ret)
335		goto leave;
336
337	/* 2. Enable output (if not already enabled) */
338	if (!(data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
339		val = data->watchdog_output_enable |
340		      SCH56XX_WDOG_OUTPUT_ENABLE;
341		ret = sch56xx_write_virtual_reg(data->addr,
342						SCH56XX_REG_WDOG_OUTPUT_ENABLE,
343						val);
344		if (ret)
345			goto leave;
346
347		data->watchdog_output_enable = val;
348	}
349
350	/* 3. Clear the watchdog event bit if set */
351	val = inb(data->addr + 9);
352	if (val & 0x01)
353		outb(0x01, data->addr + 9);
354
355leave:
356	mutex_unlock(data->io_lock);
357	return ret;
358}
359
360static int watchdog_trigger(struct watchdog_device *wddev)
361{
362	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
363	int ret;
364
365	/* Reset the watchdog countdown counter */
366	mutex_lock(data->io_lock);
367	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
368					data->watchdog_preset);
369	mutex_unlock(data->io_lock);
370
371	return ret;
372}
373
374static int watchdog_stop(struct watchdog_device *wddev)
375{
376	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
377	int ret = 0;
378	u8 val;
379
380	if (data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) {
381		val = data->watchdog_output_enable &
382		      ~SCH56XX_WDOG_OUTPUT_ENABLE;
383		mutex_lock(data->io_lock);
384		ret = sch56xx_write_virtual_reg(data->addr,
385						SCH56XX_REG_WDOG_OUTPUT_ENABLE,
386						val);
387		mutex_unlock(data->io_lock);
388		if (ret)
389			return ret;
390
391		data->watchdog_output_enable = val;
392	}
393
394	return ret;
395}
396
397static const struct watchdog_ops watchdog_ops = {
398	.owner		= THIS_MODULE,
399	.start		= watchdog_start,
400	.stop		= watchdog_stop,
401	.ping		= watchdog_trigger,
402	.set_timeout	= watchdog_set_timeout,
403};
404
405struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent,
406	u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
407{
408	struct sch56xx_watchdog_data *data;
409	int err, control, output_enable;
410
411	/* Cache the watchdog registers */
412	mutex_lock(io_lock);
413	control =
414		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
415	output_enable =
416		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
417	mutex_unlock(io_lock);
418
419	if (control < 0)
420		return NULL;
421	if (output_enable < 0)
422		return NULL;
423	if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
424		pr_warn("Watchdog not enabled by BIOS, not registering\n");
425		return NULL;
426	}
427
428	data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
429	if (!data)
430		return NULL;
431
432	data->addr = addr;
433	data->io_lock = io_lock;
434
435	strlcpy(data->wdinfo.identity, "sch56xx watchdog",
436		sizeof(data->wdinfo.identity));
437	data->wdinfo.firmware_version = revision;
438	data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
439	if (!nowayout)
440		data->wdinfo.options |= WDIOF_MAGICCLOSE;
441
442	data->wddev.info = &data->wdinfo;
443	data->wddev.ops = &watchdog_ops;
444	data->wddev.parent = parent;
445	data->wddev.timeout = 60;
446	data->wddev.min_timeout = 1;
447	data->wddev.max_timeout = 255 * 60;
448	if (nowayout)
449		data->wddev.status |= WDOG_NO_WAY_OUT;
450	if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
451		data->wddev.status |= WDOG_ACTIVE;
452
453	/* Since the watchdog uses a downcounter there is no register to read
454	   the BIOS set timeout from (if any was set at all) ->
455	   Choose a preset which will give us a 1 minute timeout */
456	if (control & SCH56XX_WDOG_TIME_BASE_SEC)
457		data->watchdog_preset = 60; /* seconds */
458	else
459		data->watchdog_preset = 1; /* minute */
460
461	data->watchdog_control = control;
462	data->watchdog_output_enable = output_enable;
463
464	watchdog_set_drvdata(&data->wddev, data);
465	err = watchdog_register_device(&data->wddev);
466	if (err) {
467		pr_err("Registering watchdog chardev: %d\n", err);
468		kfree(data);
469		return NULL;
470	}
471
472	return data;
473}
474EXPORT_SYMBOL(sch56xx_watchdog_register);
475
476void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
477{
478	watchdog_unregister_device(&data->wddev);
479	kfree(data);
480}
481EXPORT_SYMBOL(sch56xx_watchdog_unregister);
482
483/*
484 * platform dev find, add and remove functions
485 */
486
487static int __init sch56xx_find(int sioaddr, unsigned short *address,
488			       const char **name)
489{
490	u8 devid;
491	int err;
492
493	err = superio_enter(sioaddr);
494	if (err)
495		return err;
496
497	devid = superio_inb(sioaddr, SIO_REG_DEVID);
498	switch (devid) {
499	case SIO_SCH5627_ID:
500		*name = "sch5627";
501		break;
502	case SIO_SCH5636_ID:
503		*name = "sch5636";
504		break;
505	default:
506		pr_debug("Unsupported device id: 0x%02x\n",
507			 (unsigned int)devid);
508		err = -ENODEV;
509		goto exit;
510	}
511
512	superio_select(sioaddr, SIO_SCH56XX_LD_EM);
513
514	if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
515		pr_warn("Device not activated\n");
516		err = -ENODEV;
517		goto exit;
518	}
519
520	/*
521	 * Warning the order of the low / high byte is the other way around
522	 * as on most other superio devices!!
523	 */
524	*address = superio_inb(sioaddr, SIO_REG_ADDR) |
525		   superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
526	if (*address == 0) {
527		pr_warn("Base address not set\n");
528		err = -ENODEV;
529		goto exit;
530	}
531
532exit:
533	superio_exit(sioaddr);
534	return err;
535}
536
537static int __init sch56xx_device_add(unsigned short address, const char *name)
538{
539	struct resource res = {
540		.start	= address,
541		.end	= address + REGION_LENGTH - 1,
542		.flags	= IORESOURCE_IO,
543	};
544	int err;
545
546	sch56xx_pdev = platform_device_alloc(name, address);
547	if (!sch56xx_pdev)
548		return -ENOMEM;
549
550	res.name = sch56xx_pdev->name;
551	err = acpi_check_resource_conflict(&res);
552	if (err)
553		goto exit_device_put;
554
555	err = platform_device_add_resources(sch56xx_pdev, &res, 1);
556	if (err) {
557		pr_err("Device resource addition failed\n");
558		goto exit_device_put;
559	}
560
561	err = platform_device_add(sch56xx_pdev);
562	if (err) {
563		pr_err("Device addition failed\n");
564		goto exit_device_put;
565	}
566
567	return 0;
568
569exit_device_put:
570	platform_device_put(sch56xx_pdev);
571
572	return err;
573}
574
575static int __init sch56xx_init(void)
576{
577	int err;
578	unsigned short address;
579	const char *name;
580
581	err = sch56xx_find(0x4e, &address, &name);
582	if (err)
583		err = sch56xx_find(0x2e, &address, &name);
584	if (err)
585		return err;
586
587	return sch56xx_device_add(address, name);
588}
589
590static void __exit sch56xx_exit(void)
591{
592	platform_device_unregister(sch56xx_pdev);
593}
594
595MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
596MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
597MODULE_LICENSE("GPL");
598
599module_init(sch56xx_init);
600module_exit(sch56xx_exit);
601