Loading...
1// SPDX-License-Identifier: GPL-2.0-or-later
2/***************************************************************************
3 * Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> *
4 * *
5 ***************************************************************************/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/platform_device.h>
12#include <linux/err.h>
13#include <linux/io.h>
14#include <linux/acpi.h>
15#include <linux/delay.h>
16#include <linux/fs.h>
17#include <linux/watchdog.h>
18#include <linux/uaccess.h>
19#include <linux/slab.h>
20#include "sch56xx-common.h"
21
22/* Insmod parameters */
23static int nowayout = WATCHDOG_NOWAYOUT;
24module_param(nowayout, int, 0);
25MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
26 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
27
28#define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */
29#define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */
30#define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */
31
32#define SIO_REG_LDSEL 0x07 /* Logical device select */
33#define SIO_REG_DEVID 0x20 /* Device ID */
34#define SIO_REG_ENABLE 0x30 /* Logical device enable */
35#define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */
36
37#define SIO_SCH5627_ID 0xC6 /* Chipset ID */
38#define SIO_SCH5636_ID 0xC7 /* Chipset ID */
39
40#define REGION_LENGTH 10
41
42#define SCH56XX_CMD_READ 0x02
43#define SCH56XX_CMD_WRITE 0x03
44
45/* Watchdog registers */
46#define SCH56XX_REG_WDOG_PRESET 0x58B
47#define SCH56XX_REG_WDOG_CONTROL 0x58C
48#define SCH56XX_WDOG_TIME_BASE_SEC 0x01
49#define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E
50#define SCH56XX_WDOG_OUTPUT_ENABLE 0x02
51
52struct sch56xx_watchdog_data {
53 u16 addr;
54 struct mutex *io_lock;
55 struct watchdog_info wdinfo;
56 struct watchdog_device wddev;
57 u8 watchdog_preset;
58 u8 watchdog_control;
59 u8 watchdog_output_enable;
60};
61
62static struct platform_device *sch56xx_pdev;
63
64/* Super I/O functions */
65static inline int superio_inb(int base, int reg)
66{
67 outb(reg, base);
68 return inb(base + 1);
69}
70
71static inline int superio_enter(int base)
72{
73 /* Don't step on other drivers' I/O space by accident */
74 if (!request_muxed_region(base, 2, "sch56xx")) {
75 pr_err("I/O address 0x%04x already in use\n", base);
76 return -EBUSY;
77 }
78
79 outb(SIO_UNLOCK_KEY, base);
80
81 return 0;
82}
83
84static inline void superio_select(int base, int ld)
85{
86 outb(SIO_REG_LDSEL, base);
87 outb(ld, base + 1);
88}
89
90static inline void superio_exit(int base)
91{
92 outb(SIO_LOCK_KEY, base);
93 release_region(base, 2);
94}
95
96static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
97{
98 u8 val;
99 int i;
100 /*
101 * According to SMSC for the commands we use the maximum time for
102 * the EM to respond is 15 ms, but testing shows in practice it
103 * responds within 15-32 reads, so we first busy poll, and if
104 * that fails sleep a bit and try again until we are way past
105 * the 15 ms maximum response time.
106 */
107 const int max_busy_polls = 64;
108 const int max_lazy_polls = 32;
109
110 /* (Optional) Write-Clear the EC to Host Mailbox Register */
111 val = inb(addr + 1);
112 outb(val, addr + 1);
113
114 /* Set Mailbox Address Pointer to first location in Region 1 */
115 outb(0x00, addr + 2);
116 outb(0x80, addr + 3);
117
118 /* Write Request Packet Header */
119 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
120 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
121 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
122
123 /* Write Value field */
124 if (cmd == SCH56XX_CMD_WRITE)
125 outb(v, addr + 4);
126
127 /* Write Address field */
128 outb(reg & 0xff, addr + 6);
129 outb(reg >> 8, addr + 7);
130
131 /* Execute the Random Access Command */
132 outb(0x01, addr); /* Write 01h to the Host-to-EC register */
133
134 /* EM Interface Polling "Algorithm" */
135 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
136 if (i >= max_busy_polls)
137 msleep(1);
138 /* Read Interrupt source Register */
139 val = inb(addr + 8);
140 /* Write Clear the interrupt source bits */
141 if (val)
142 outb(val, addr + 8);
143 /* Command Completed ? */
144 if (val & 0x01)
145 break;
146 }
147 if (i == max_busy_polls + max_lazy_polls) {
148 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
149 reg, 1);
150 return -EIO;
151 }
152
153 /*
154 * According to SMSC we may need to retry this, but sofar I've always
155 * seen this succeed in 1 try.
156 */
157 for (i = 0; i < max_busy_polls; i++) {
158 /* Read EC-to-Host Register */
159 val = inb(addr + 1);
160 /* Command Completed ? */
161 if (val == 0x01)
162 break;
163
164 if (i == 0)
165 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
166 (unsigned int)val, reg);
167 }
168 if (i == max_busy_polls) {
169 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
170 reg, 2);
171 return -EIO;
172 }
173
174 /*
175 * According to the SMSC app note we should now do:
176 *
177 * Set Mailbox Address Pointer to first location in Region 1 *
178 * outb(0x00, addr + 2);
179 * outb(0x80, addr + 3);
180 *
181 * But if we do that things don't work, so let's not.
182 */
183
184 /* Read Value field */
185 if (cmd == SCH56XX_CMD_READ)
186 return inb(addr + 4);
187
188 return 0;
189}
190
191int sch56xx_read_virtual_reg(u16 addr, u16 reg)
192{
193 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
194}
195EXPORT_SYMBOL(sch56xx_read_virtual_reg);
196
197int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
198{
199 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
200}
201EXPORT_SYMBOL(sch56xx_write_virtual_reg);
202
203int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
204{
205 int lsb, msb;
206
207 /* Read LSB first, this will cause the matching MSB to be latched */
208 lsb = sch56xx_read_virtual_reg(addr, reg);
209 if (lsb < 0)
210 return lsb;
211
212 msb = sch56xx_read_virtual_reg(addr, reg + 1);
213 if (msb < 0)
214 return msb;
215
216 return lsb | (msb << 8);
217}
218EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
219
220int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
221 int high_nibble)
222{
223 int msb, lsn;
224
225 /* Read MSB first, this will cause the matching LSN to be latched */
226 msb = sch56xx_read_virtual_reg(addr, msb_reg);
227 if (msb < 0)
228 return msb;
229
230 lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
231 if (lsn < 0)
232 return lsn;
233
234 if (high_nibble)
235 return (msb << 4) | (lsn >> 4);
236 else
237 return (msb << 4) | (lsn & 0x0f);
238}
239EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
240
241/*
242 * Watchdog routines
243 */
244
245static int watchdog_set_timeout(struct watchdog_device *wddev,
246 unsigned int timeout)
247{
248 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
249 unsigned int resolution;
250 u8 control;
251 int ret;
252
253 /* 1 second or 60 second resolution? */
254 if (timeout <= 255)
255 resolution = 1;
256 else
257 resolution = 60;
258
259 if (timeout < resolution || timeout > (resolution * 255))
260 return -EINVAL;
261
262 if (resolution == 1)
263 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
264 else
265 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
266
267 if (data->watchdog_control != control) {
268 mutex_lock(data->io_lock);
269 ret = sch56xx_write_virtual_reg(data->addr,
270 SCH56XX_REG_WDOG_CONTROL,
271 control);
272 mutex_unlock(data->io_lock);
273 if (ret)
274 return ret;
275
276 data->watchdog_control = control;
277 }
278
279 /*
280 * Remember new timeout value, but do not write as that (re)starts
281 * the watchdog countdown.
282 */
283 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
284 wddev->timeout = data->watchdog_preset * resolution;
285
286 return 0;
287}
288
289static int watchdog_start(struct watchdog_device *wddev)
290{
291 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
292 int ret;
293 u8 val;
294
295 /*
296 * The sch56xx's watchdog cannot really be started / stopped
297 * it is always running, but we can avoid the timer expiring
298 * from causing a system reset by clearing the output enable bit.
299 *
300 * The sch56xx's watchdog will set the watchdog event bit, bit 0
301 * of the second interrupt source register (at base-address + 9),
302 * when the timer expires.
303 *
304 * This will only cause a system reset if the 0-1 flank happens when
305 * output enable is true. Setting output enable after the flank will
306 * not cause a reset, nor will the timer expiring a second time.
307 * This means we must clear the watchdog event bit in case it is set.
308 *
309 * The timer may still be running (after a recent watchdog_stop) and
310 * mere milliseconds away from expiring, so the timer must be reset
311 * first!
312 */
313
314 mutex_lock(data->io_lock);
315
316 /* 1. Reset the watchdog countdown counter */
317 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
318 data->watchdog_preset);
319 if (ret)
320 goto leave;
321
322 /* 2. Enable output */
323 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
324 ret = sch56xx_write_virtual_reg(data->addr,
325 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
326 if (ret)
327 goto leave;
328
329 data->watchdog_output_enable = val;
330
331 /* 3. Clear the watchdog event bit if set */
332 val = inb(data->addr + 9);
333 if (val & 0x01)
334 outb(0x01, data->addr + 9);
335
336leave:
337 mutex_unlock(data->io_lock);
338 return ret;
339}
340
341static int watchdog_trigger(struct watchdog_device *wddev)
342{
343 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
344 int ret;
345
346 /* Reset the watchdog countdown counter */
347 mutex_lock(data->io_lock);
348 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
349 data->watchdog_preset);
350 mutex_unlock(data->io_lock);
351
352 return ret;
353}
354
355static int watchdog_stop(struct watchdog_device *wddev)
356{
357 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
358 int ret = 0;
359 u8 val;
360
361 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
362 mutex_lock(data->io_lock);
363 ret = sch56xx_write_virtual_reg(data->addr,
364 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
365 mutex_unlock(data->io_lock);
366 if (ret)
367 return ret;
368
369 data->watchdog_output_enable = val;
370 return 0;
371}
372
373static const struct watchdog_ops watchdog_ops = {
374 .owner = THIS_MODULE,
375 .start = watchdog_start,
376 .stop = watchdog_stop,
377 .ping = watchdog_trigger,
378 .set_timeout = watchdog_set_timeout,
379};
380
381struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent,
382 u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
383{
384 struct sch56xx_watchdog_data *data;
385 int err, control, output_enable;
386
387 /* Cache the watchdog registers */
388 mutex_lock(io_lock);
389 control =
390 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
391 output_enable =
392 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
393 mutex_unlock(io_lock);
394
395 if (control < 0)
396 return NULL;
397 if (output_enable < 0)
398 return NULL;
399 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
400 pr_warn("Watchdog not enabled by BIOS, not registering\n");
401 return NULL;
402 }
403
404 data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
405 if (!data)
406 return NULL;
407
408 data->addr = addr;
409 data->io_lock = io_lock;
410
411 strlcpy(data->wdinfo.identity, "sch56xx watchdog",
412 sizeof(data->wdinfo.identity));
413 data->wdinfo.firmware_version = revision;
414 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
415 if (!nowayout)
416 data->wdinfo.options |= WDIOF_MAGICCLOSE;
417
418 data->wddev.info = &data->wdinfo;
419 data->wddev.ops = &watchdog_ops;
420 data->wddev.parent = parent;
421 data->wddev.timeout = 60;
422 data->wddev.min_timeout = 1;
423 data->wddev.max_timeout = 255 * 60;
424 if (nowayout)
425 set_bit(WDOG_NO_WAY_OUT, &data->wddev.status);
426 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
427 set_bit(WDOG_ACTIVE, &data->wddev.status);
428
429 /* Since the watchdog uses a downcounter there is no register to read
430 the BIOS set timeout from (if any was set at all) ->
431 Choose a preset which will give us a 1 minute timeout */
432 if (control & SCH56XX_WDOG_TIME_BASE_SEC)
433 data->watchdog_preset = 60; /* seconds */
434 else
435 data->watchdog_preset = 1; /* minute */
436
437 data->watchdog_control = control;
438 data->watchdog_output_enable = output_enable;
439
440 watchdog_set_drvdata(&data->wddev, data);
441 err = watchdog_register_device(&data->wddev);
442 if (err) {
443 pr_err("Registering watchdog chardev: %d\n", err);
444 kfree(data);
445 return NULL;
446 }
447
448 return data;
449}
450EXPORT_SYMBOL(sch56xx_watchdog_register);
451
452void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
453{
454 watchdog_unregister_device(&data->wddev);
455 kfree(data);
456}
457EXPORT_SYMBOL(sch56xx_watchdog_unregister);
458
459/*
460 * platform dev find, add and remove functions
461 */
462
463static int __init sch56xx_find(int sioaddr, const char **name)
464{
465 u8 devid;
466 unsigned short address;
467 int err;
468
469 err = superio_enter(sioaddr);
470 if (err)
471 return err;
472
473 devid = superio_inb(sioaddr, SIO_REG_DEVID);
474 switch (devid) {
475 case SIO_SCH5627_ID:
476 *name = "sch5627";
477 break;
478 case SIO_SCH5636_ID:
479 *name = "sch5636";
480 break;
481 default:
482 pr_debug("Unsupported device id: 0x%02x\n",
483 (unsigned int)devid);
484 err = -ENODEV;
485 goto exit;
486 }
487
488 superio_select(sioaddr, SIO_SCH56XX_LD_EM);
489
490 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
491 pr_warn("Device not activated\n");
492 err = -ENODEV;
493 goto exit;
494 }
495
496 /*
497 * Warning the order of the low / high byte is the other way around
498 * as on most other superio devices!!
499 */
500 address = superio_inb(sioaddr, SIO_REG_ADDR) |
501 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
502 if (address == 0) {
503 pr_warn("Base address not set\n");
504 err = -ENODEV;
505 goto exit;
506 }
507 err = address;
508
509exit:
510 superio_exit(sioaddr);
511 return err;
512}
513
514static int __init sch56xx_device_add(int address, const char *name)
515{
516 struct resource res = {
517 .start = address,
518 .end = address + REGION_LENGTH - 1,
519 .flags = IORESOURCE_IO,
520 };
521 int err;
522
523 sch56xx_pdev = platform_device_alloc(name, address);
524 if (!sch56xx_pdev)
525 return -ENOMEM;
526
527 res.name = sch56xx_pdev->name;
528 err = acpi_check_resource_conflict(&res);
529 if (err)
530 goto exit_device_put;
531
532 err = platform_device_add_resources(sch56xx_pdev, &res, 1);
533 if (err) {
534 pr_err("Device resource addition failed\n");
535 goto exit_device_put;
536 }
537
538 err = platform_device_add(sch56xx_pdev);
539 if (err) {
540 pr_err("Device addition failed\n");
541 goto exit_device_put;
542 }
543
544 return 0;
545
546exit_device_put:
547 platform_device_put(sch56xx_pdev);
548
549 return err;
550}
551
552static int __init sch56xx_init(void)
553{
554 int address;
555 const char *name = NULL;
556
557 address = sch56xx_find(0x4e, &name);
558 if (address < 0)
559 address = sch56xx_find(0x2e, &name);
560 if (address < 0)
561 return address;
562
563 return sch56xx_device_add(address, name);
564}
565
566static void __exit sch56xx_exit(void)
567{
568 platform_device_unregister(sch56xx_pdev);
569}
570
571MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
572MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
573MODULE_LICENSE("GPL");
574
575module_init(sch56xx_init);
576module_exit(sch56xx_exit);
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 kref kref;
71 struct watchdog_info wdinfo;
72 struct watchdog_device wddev;
73 u8 watchdog_preset;
74 u8 watchdog_control;
75 u8 watchdog_output_enable;
76};
77
78static struct platform_device *sch56xx_pdev;
79
80/* Super I/O functions */
81static inline int superio_inb(int base, int reg)
82{
83 outb(reg, base);
84 return inb(base + 1);
85}
86
87static inline int superio_enter(int base)
88{
89 /* Don't step on other drivers' I/O space by accident */
90 if (!request_muxed_region(base, 2, "sch56xx")) {
91 pr_err("I/O address 0x%04x already in use\n", base);
92 return -EBUSY;
93 }
94
95 outb(SIO_UNLOCK_KEY, base);
96
97 return 0;
98}
99
100static inline void superio_select(int base, int ld)
101{
102 outb(SIO_REG_LDSEL, base);
103 outb(ld, base + 1);
104}
105
106static inline void superio_exit(int base)
107{
108 outb(SIO_LOCK_KEY, base);
109 release_region(base, 2);
110}
111
112static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
113{
114 u8 val;
115 int i;
116 /*
117 * According to SMSC for the commands we use the maximum time for
118 * the EM to respond is 15 ms, but testing shows in practice it
119 * responds within 15-32 reads, so we first busy poll, and if
120 * that fails sleep a bit and try again until we are way past
121 * the 15 ms maximum response time.
122 */
123 const int max_busy_polls = 64;
124 const int max_lazy_polls = 32;
125
126 /* (Optional) Write-Clear the EC to Host Mailbox Register */
127 val = inb(addr + 1);
128 outb(val, addr + 1);
129
130 /* Set Mailbox Address Pointer to first location in Region 1 */
131 outb(0x00, addr + 2);
132 outb(0x80, addr + 3);
133
134 /* Write Request Packet Header */
135 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
136 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
137 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
138
139 /* Write Value field */
140 if (cmd == SCH56XX_CMD_WRITE)
141 outb(v, addr + 4);
142
143 /* Write Address field */
144 outb(reg & 0xff, addr + 6);
145 outb(reg >> 8, addr + 7);
146
147 /* Execute the Random Access Command */
148 outb(0x01, addr); /* Write 01h to the Host-to-EC register */
149
150 /* EM Interface Polling "Algorithm" */
151 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
152 if (i >= max_busy_polls)
153 msleep(1);
154 /* Read Interrupt source Register */
155 val = inb(addr + 8);
156 /* Write Clear the interrupt source bits */
157 if (val)
158 outb(val, addr + 8);
159 /* Command Completed ? */
160 if (val & 0x01)
161 break;
162 }
163 if (i == max_busy_polls + max_lazy_polls) {
164 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
165 reg, 1);
166 return -EIO;
167 }
168
169 /*
170 * According to SMSC we may need to retry this, but sofar I've always
171 * seen this succeed in 1 try.
172 */
173 for (i = 0; i < max_busy_polls; i++) {
174 /* Read EC-to-Host Register */
175 val = inb(addr + 1);
176 /* Command Completed ? */
177 if (val == 0x01)
178 break;
179
180 if (i == 0)
181 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
182 (unsigned int)val, reg);
183 }
184 if (i == max_busy_polls) {
185 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
186 reg, 2);
187 return -EIO;
188 }
189
190 /*
191 * According to the SMSC app note we should now do:
192 *
193 * Set Mailbox Address Pointer to first location in Region 1 *
194 * outb(0x00, addr + 2);
195 * outb(0x80, addr + 3);
196 *
197 * But if we do that things don't work, so let's not.
198 */
199
200 /* Read Value field */
201 if (cmd == SCH56XX_CMD_READ)
202 return inb(addr + 4);
203
204 return 0;
205}
206
207int sch56xx_read_virtual_reg(u16 addr, u16 reg)
208{
209 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
210}
211EXPORT_SYMBOL(sch56xx_read_virtual_reg);
212
213int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
214{
215 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
216}
217EXPORT_SYMBOL(sch56xx_write_virtual_reg);
218
219int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
220{
221 int lsb, msb;
222
223 /* Read LSB first, this will cause the matching MSB to be latched */
224 lsb = sch56xx_read_virtual_reg(addr, reg);
225 if (lsb < 0)
226 return lsb;
227
228 msb = sch56xx_read_virtual_reg(addr, reg + 1);
229 if (msb < 0)
230 return msb;
231
232 return lsb | (msb << 8);
233}
234EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
235
236int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
237 int high_nibble)
238{
239 int msb, lsn;
240
241 /* Read MSB first, this will cause the matching LSN to be latched */
242 msb = sch56xx_read_virtual_reg(addr, msb_reg);
243 if (msb < 0)
244 return msb;
245
246 lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
247 if (lsn < 0)
248 return lsn;
249
250 if (high_nibble)
251 return (msb << 4) | (lsn >> 4);
252 else
253 return (msb << 4) | (lsn & 0x0f);
254}
255EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
256
257/*
258 * Watchdog routines
259 */
260
261/* Release our data struct when we're unregistered *and*
262 all references to our watchdog device are released */
263static void watchdog_release_resources(struct kref *r)
264{
265 struct sch56xx_watchdog_data *data =
266 container_of(r, struct sch56xx_watchdog_data, kref);
267 kfree(data);
268}
269
270static int watchdog_set_timeout(struct watchdog_device *wddev,
271 unsigned int timeout)
272{
273 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
274 unsigned int resolution;
275 u8 control;
276 int ret;
277
278 /* 1 second or 60 second resolution? */
279 if (timeout <= 255)
280 resolution = 1;
281 else
282 resolution = 60;
283
284 if (timeout < resolution || timeout > (resolution * 255))
285 return -EINVAL;
286
287 if (resolution == 1)
288 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
289 else
290 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
291
292 if (data->watchdog_control != control) {
293 mutex_lock(data->io_lock);
294 ret = sch56xx_write_virtual_reg(data->addr,
295 SCH56XX_REG_WDOG_CONTROL,
296 control);
297 mutex_unlock(data->io_lock);
298 if (ret)
299 return ret;
300
301 data->watchdog_control = control;
302 }
303
304 /*
305 * Remember new timeout value, but do not write as that (re)starts
306 * the watchdog countdown.
307 */
308 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
309 wddev->timeout = data->watchdog_preset * resolution;
310
311 return 0;
312}
313
314static int watchdog_start(struct watchdog_device *wddev)
315{
316 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
317 int ret;
318 u8 val;
319
320 /*
321 * The sch56xx's watchdog cannot really be started / stopped
322 * it is always running, but we can avoid the timer expiring
323 * from causing a system reset by clearing the output enable bit.
324 *
325 * The sch56xx's watchdog will set the watchdog event bit, bit 0
326 * of the second interrupt source register (at base-address + 9),
327 * when the timer expires.
328 *
329 * This will only cause a system reset if the 0-1 flank happens when
330 * output enable is true. Setting output enable after the flank will
331 * not cause a reset, nor will the timer expiring a second time.
332 * This means we must clear the watchdog event bit in case it is set.
333 *
334 * The timer may still be running (after a recent watchdog_stop) and
335 * mere milliseconds away from expiring, so the timer must be reset
336 * first!
337 */
338
339 mutex_lock(data->io_lock);
340
341 /* 1. Reset the watchdog countdown counter */
342 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
343 data->watchdog_preset);
344 if (ret)
345 goto leave;
346
347 /* 2. Enable output */
348 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
349 ret = sch56xx_write_virtual_reg(data->addr,
350 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
351 if (ret)
352 goto leave;
353
354 data->watchdog_output_enable = val;
355
356 /* 3. Clear the watchdog event bit if set */
357 val = inb(data->addr + 9);
358 if (val & 0x01)
359 outb(0x01, data->addr + 9);
360
361leave:
362 mutex_unlock(data->io_lock);
363 return ret;
364}
365
366static int watchdog_trigger(struct watchdog_device *wddev)
367{
368 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
369 int ret;
370
371 /* Reset the watchdog countdown counter */
372 mutex_lock(data->io_lock);
373 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
374 data->watchdog_preset);
375 mutex_unlock(data->io_lock);
376
377 return ret;
378}
379
380static int watchdog_stop(struct watchdog_device *wddev)
381{
382 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
383 int ret = 0;
384 u8 val;
385
386 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
387 mutex_lock(data->io_lock);
388 ret = sch56xx_write_virtual_reg(data->addr,
389 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
390 mutex_unlock(data->io_lock);
391 if (ret)
392 return ret;
393
394 data->watchdog_output_enable = val;
395 return 0;
396}
397
398static void watchdog_ref(struct watchdog_device *wddev)
399{
400 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
401
402 kref_get(&data->kref);
403}
404
405static void watchdog_unref(struct watchdog_device *wddev)
406{
407 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
408
409 kref_put(&data->kref, watchdog_release_resources);
410}
411
412static const struct watchdog_ops watchdog_ops = {
413 .owner = THIS_MODULE,
414 .start = watchdog_start,
415 .stop = watchdog_stop,
416 .ping = watchdog_trigger,
417 .set_timeout = watchdog_set_timeout,
418 .ref = watchdog_ref,
419 .unref = watchdog_unref,
420};
421
422struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent,
423 u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
424{
425 struct sch56xx_watchdog_data *data;
426 int err, control, output_enable;
427
428 /* Cache the watchdog registers */
429 mutex_lock(io_lock);
430 control =
431 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
432 output_enable =
433 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
434 mutex_unlock(io_lock);
435
436 if (control < 0)
437 return NULL;
438 if (output_enable < 0)
439 return NULL;
440 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
441 pr_warn("Watchdog not enabled by BIOS, not registering\n");
442 return NULL;
443 }
444
445 data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
446 if (!data)
447 return NULL;
448
449 data->addr = addr;
450 data->io_lock = io_lock;
451 kref_init(&data->kref);
452
453 strlcpy(data->wdinfo.identity, "sch56xx watchdog",
454 sizeof(data->wdinfo.identity));
455 data->wdinfo.firmware_version = revision;
456 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
457 if (!nowayout)
458 data->wdinfo.options |= WDIOF_MAGICCLOSE;
459
460 data->wddev.info = &data->wdinfo;
461 data->wddev.ops = &watchdog_ops;
462 data->wddev.parent = parent;
463 data->wddev.timeout = 60;
464 data->wddev.min_timeout = 1;
465 data->wddev.max_timeout = 255 * 60;
466 if (nowayout)
467 set_bit(WDOG_NO_WAY_OUT, &data->wddev.status);
468 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
469 set_bit(WDOG_ACTIVE, &data->wddev.status);
470
471 /* Since the watchdog uses a downcounter there is no register to read
472 the BIOS set timeout from (if any was set at all) ->
473 Choose a preset which will give us a 1 minute timeout */
474 if (control & SCH56XX_WDOG_TIME_BASE_SEC)
475 data->watchdog_preset = 60; /* seconds */
476 else
477 data->watchdog_preset = 1; /* minute */
478
479 data->watchdog_control = control;
480 data->watchdog_output_enable = output_enable;
481
482 watchdog_set_drvdata(&data->wddev, data);
483 err = watchdog_register_device(&data->wddev);
484 if (err) {
485 pr_err("Registering watchdog chardev: %d\n", err);
486 kfree(data);
487 return NULL;
488 }
489
490 return data;
491}
492EXPORT_SYMBOL(sch56xx_watchdog_register);
493
494void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
495{
496 watchdog_unregister_device(&data->wddev);
497 kref_put(&data->kref, watchdog_release_resources);
498 /* Don't touch data after this it may have been free-ed! */
499}
500EXPORT_SYMBOL(sch56xx_watchdog_unregister);
501
502/*
503 * platform dev find, add and remove functions
504 */
505
506static int __init sch56xx_find(int sioaddr, const char **name)
507{
508 u8 devid;
509 unsigned short address;
510 int err;
511
512 err = superio_enter(sioaddr);
513 if (err)
514 return err;
515
516 devid = superio_inb(sioaddr, SIO_REG_DEVID);
517 switch (devid) {
518 case SIO_SCH5627_ID:
519 *name = "sch5627";
520 break;
521 case SIO_SCH5636_ID:
522 *name = "sch5636";
523 break;
524 default:
525 pr_debug("Unsupported device id: 0x%02x\n",
526 (unsigned int)devid);
527 err = -ENODEV;
528 goto exit;
529 }
530
531 superio_select(sioaddr, SIO_SCH56XX_LD_EM);
532
533 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
534 pr_warn("Device not activated\n");
535 err = -ENODEV;
536 goto exit;
537 }
538
539 /*
540 * Warning the order of the low / high byte is the other way around
541 * as on most other superio devices!!
542 */
543 address = superio_inb(sioaddr, SIO_REG_ADDR) |
544 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
545 if (address == 0) {
546 pr_warn("Base address not set\n");
547 err = -ENODEV;
548 goto exit;
549 }
550 err = address;
551
552exit:
553 superio_exit(sioaddr);
554 return err;
555}
556
557static int __init sch56xx_device_add(int address, const char *name)
558{
559 struct resource res = {
560 .start = address,
561 .end = address + REGION_LENGTH - 1,
562 .flags = IORESOURCE_IO,
563 };
564 int err;
565
566 sch56xx_pdev = platform_device_alloc(name, address);
567 if (!sch56xx_pdev)
568 return -ENOMEM;
569
570 res.name = sch56xx_pdev->name;
571 err = acpi_check_resource_conflict(&res);
572 if (err)
573 goto exit_device_put;
574
575 err = platform_device_add_resources(sch56xx_pdev, &res, 1);
576 if (err) {
577 pr_err("Device resource addition failed\n");
578 goto exit_device_put;
579 }
580
581 err = platform_device_add(sch56xx_pdev);
582 if (err) {
583 pr_err("Device addition failed\n");
584 goto exit_device_put;
585 }
586
587 return 0;
588
589exit_device_put:
590 platform_device_put(sch56xx_pdev);
591
592 return err;
593}
594
595static int __init sch56xx_init(void)
596{
597 int address;
598 const char *name = NULL;
599
600 address = sch56xx_find(0x4e, &name);
601 if (address < 0)
602 address = sch56xx_find(0x2e, &name);
603 if (address < 0)
604 return address;
605
606 return sch56xx_device_add(address, name);
607}
608
609static void __exit sch56xx_exit(void)
610{
611 platform_device_unregister(sch56xx_pdev);
612}
613
614MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
615MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
616MODULE_LICENSE("GPL");
617
618module_init(sch56xx_init);
619module_exit(sch56xx_exit);