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