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/regmap.h>
13 #include <linux/err.h>
14 #include <linux/io.h>
15 #include <linux/acpi.h>
16 #include <linux/delay.h>
17 #include <linux/fs.h>
18 #include <linux/watchdog.h>
19 #include <linux/uaccess.h>
20 #include <linux/slab.h>
21 #include "sch56xx-common.h"
22
23 /* Insmod parameters */
24 static bool nowayout = WATCHDOG_NOWAYOUT;
25 module_param(nowayout, bool, 0);
26 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
27 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
28
29 #define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */
30 #define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */
31 #define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */
32
33 #define SIO_REG_LDSEL 0x07 /* Logical device select */
34 #define SIO_REG_DEVID 0x20 /* Device ID */
35 #define SIO_REG_ENABLE 0x30 /* Logical device enable */
36 #define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */
37
38 #define SIO_SCH5627_ID 0xC6 /* Chipset ID */
39 #define SIO_SCH5636_ID 0xC7 /* Chipset ID */
40
41 #define REGION_LENGTH 10
42
43 #define SCH56XX_CMD_READ 0x02
44 #define SCH56XX_CMD_WRITE 0x03
45
46 /* Watchdog registers */
47 #define SCH56XX_REG_WDOG_PRESET 0x58B
48 #define SCH56XX_REG_WDOG_CONTROL 0x58C
49 #define SCH56XX_WDOG_TIME_BASE_SEC 0x01
50 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E
51 #define SCH56XX_WDOG_OUTPUT_ENABLE 0x02
52
53 struct sch56xx_watchdog_data {
54 u16 addr;
55 struct mutex *io_lock;
56 struct watchdog_info wdinfo;
57 struct watchdog_device wddev;
58 u8 watchdog_preset;
59 u8 watchdog_control;
60 u8 watchdog_output_enable;
61 };
62
63 struct sch56xx_bus_context {
64 struct mutex *lock; /* Used to serialize access to the mailbox registers */
65 u16 addr;
66 };
67
68 static struct platform_device *sch56xx_pdev;
69
70 /* Super I/O functions */
superio_inb(int base,int reg)71 static inline int superio_inb(int base, int reg)
72 {
73 outb(reg, base);
74 return inb(base + 1);
75 }
76
superio_enter(int base)77 static inline int superio_enter(int base)
78 {
79 /* Don't step on other drivers' I/O space by accident */
80 if (!request_muxed_region(base, 2, "sch56xx")) {
81 pr_err("I/O address 0x%04x already in use\n", base);
82 return -EBUSY;
83 }
84
85 outb(SIO_UNLOCK_KEY, base);
86
87 return 0;
88 }
89
superio_select(int base,int ld)90 static inline void superio_select(int base, int ld)
91 {
92 outb(SIO_REG_LDSEL, base);
93 outb(ld, base + 1);
94 }
95
superio_exit(int base)96 static inline void superio_exit(int base)
97 {
98 outb(SIO_LOCK_KEY, base);
99 release_region(base, 2);
100 }
101
sch56xx_send_cmd(u16 addr,u8 cmd,u16 reg,u8 v)102 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
103 {
104 u8 val;
105 int i;
106 /*
107 * According to SMSC for the commands we use the maximum time for
108 * the EM to respond is 15 ms, but testing shows in practice it
109 * responds within 15-32 reads, so we first busy poll, and if
110 * that fails sleep a bit and try again until we are way past
111 * the 15 ms maximum response time.
112 */
113 const int max_busy_polls = 64;
114 const int max_lazy_polls = 32;
115
116 /* (Optional) Write-Clear the EC to Host Mailbox Register */
117 val = inb(addr + 1);
118 outb(val, addr + 1);
119
120 /* Set Mailbox Address Pointer to first location in Region 1 */
121 outb(0x00, addr + 2);
122 outb(0x80, addr + 3);
123
124 /* Write Request Packet Header */
125 outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
126 outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
127 outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
128
129 /* Write Value field */
130 if (cmd == SCH56XX_CMD_WRITE)
131 outb(v, addr + 4);
132
133 /* Write Address field */
134 outb(reg & 0xff, addr + 6);
135 outb(reg >> 8, addr + 7);
136
137 /* Execute the Random Access Command */
138 outb(0x01, addr); /* Write 01h to the Host-to-EC register */
139
140 /* EM Interface Polling "Algorithm" */
141 for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
142 if (i >= max_busy_polls)
143 usleep_range(1000, 2000);
144 /* Read Interrupt source Register */
145 val = inb(addr + 8);
146 /* Write Clear the interrupt source bits */
147 if (val)
148 outb(val, addr + 8);
149 /* Command Completed ? */
150 if (val & 0x01)
151 break;
152 }
153 if (i == max_busy_polls + max_lazy_polls) {
154 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
155 reg, 1);
156 return -EIO;
157 }
158
159 /*
160 * According to SMSC we may need to retry this, but sofar I've always
161 * seen this succeed in 1 try.
162 */
163 for (i = 0; i < max_busy_polls; i++) {
164 /* Read EC-to-Host Register */
165 val = inb(addr + 1);
166 /* Command Completed ? */
167 if (val == 0x01)
168 break;
169
170 if (i == 0)
171 pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
172 (unsigned int)val, reg);
173 }
174 if (i == max_busy_polls) {
175 pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
176 reg, 2);
177 return -EIO;
178 }
179
180 /*
181 * According to the SMSC app note we should now do:
182 *
183 * Set Mailbox Address Pointer to first location in Region 1 *
184 * outb(0x00, addr + 2);
185 * outb(0x80, addr + 3);
186 *
187 * But if we do that things don't work, so let's not.
188 */
189
190 /* Read Value field */
191 if (cmd == SCH56XX_CMD_READ)
192 return inb(addr + 4);
193
194 return 0;
195 }
196
sch56xx_read_virtual_reg(u16 addr,u16 reg)197 int sch56xx_read_virtual_reg(u16 addr, u16 reg)
198 {
199 return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
200 }
201 EXPORT_SYMBOL(sch56xx_read_virtual_reg);
202
sch56xx_write_virtual_reg(u16 addr,u16 reg,u8 val)203 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
204 {
205 return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
206 }
207 EXPORT_SYMBOL(sch56xx_write_virtual_reg);
208
sch56xx_read_virtual_reg16(u16 addr,u16 reg)209 int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
210 {
211 int lsb, msb;
212
213 /* Read LSB first, this will cause the matching MSB to be latched */
214 lsb = sch56xx_read_virtual_reg(addr, reg);
215 if (lsb < 0)
216 return lsb;
217
218 msb = sch56xx_read_virtual_reg(addr, reg + 1);
219 if (msb < 0)
220 return msb;
221
222 return lsb | (msb << 8);
223 }
224 EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
225
sch56xx_read_virtual_reg12(u16 addr,u16 msb_reg,u16 lsn_reg,int high_nibble)226 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
227 int high_nibble)
228 {
229 int msb, lsn;
230
231 /* Read MSB first, this will cause the matching LSN to be latched */
232 msb = sch56xx_read_virtual_reg(addr, msb_reg);
233 if (msb < 0)
234 return msb;
235
236 lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
237 if (lsn < 0)
238 return lsn;
239
240 if (high_nibble)
241 return (msb << 4) | (lsn >> 4);
242 else
243 return (msb << 4) | (lsn & 0x0f);
244 }
245 EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
246
247 /*
248 * Regmap support
249 */
250
sch56xx_regmap_read16(struct regmap * map,unsigned int reg,unsigned int * val)251 int sch56xx_regmap_read16(struct regmap *map, unsigned int reg, unsigned int *val)
252 {
253 int lsb, msb, ret;
254
255 /* See sch56xx_read_virtual_reg16() */
256 ret = regmap_read(map, reg, &lsb);
257 if (ret < 0)
258 return ret;
259
260 ret = regmap_read(map, reg + 1, &msb);
261 if (ret < 0)
262 return ret;
263
264 *val = lsb | (msb << 8);
265
266 return 0;
267 }
268 EXPORT_SYMBOL(sch56xx_regmap_read16);
269
sch56xx_regmap_write16(struct regmap * map,unsigned int reg,unsigned int val)270 int sch56xx_regmap_write16(struct regmap *map, unsigned int reg, unsigned int val)
271 {
272 int ret;
273
274 ret = regmap_write(map, reg, val & 0xff);
275 if (ret < 0)
276 return ret;
277
278 return regmap_write(map, reg + 1, (val >> 8) & 0xff);
279 }
280 EXPORT_SYMBOL(sch56xx_regmap_write16);
281
sch56xx_reg_write(void * context,unsigned int reg,unsigned int val)282 static int sch56xx_reg_write(void *context, unsigned int reg, unsigned int val)
283 {
284 struct sch56xx_bus_context *bus = context;
285 int ret;
286
287 mutex_lock(bus->lock);
288 ret = sch56xx_write_virtual_reg(bus->addr, (u16)reg, (u8)val);
289 mutex_unlock(bus->lock);
290
291 return ret;
292 }
293
sch56xx_reg_read(void * context,unsigned int reg,unsigned int * val)294 static int sch56xx_reg_read(void *context, unsigned int reg, unsigned int *val)
295 {
296 struct sch56xx_bus_context *bus = context;
297 int ret;
298
299 mutex_lock(bus->lock);
300 ret = sch56xx_read_virtual_reg(bus->addr, (u16)reg);
301 mutex_unlock(bus->lock);
302
303 if (ret < 0)
304 return ret;
305
306 *val = ret;
307
308 return 0;
309 }
310
sch56xx_free_context(void * context)311 static void sch56xx_free_context(void *context)
312 {
313 kfree(context);
314 }
315
316 static const struct regmap_bus sch56xx_bus = {
317 .reg_write = sch56xx_reg_write,
318 .reg_read = sch56xx_reg_read,
319 .free_context = sch56xx_free_context,
320 .reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
321 .val_format_endian_default = REGMAP_ENDIAN_LITTLE,
322 };
323
devm_regmap_init_sch56xx(struct device * dev,struct mutex * lock,u16 addr,const struct regmap_config * config)324 struct regmap *devm_regmap_init_sch56xx(struct device *dev, struct mutex *lock, u16 addr,
325 const struct regmap_config *config)
326 {
327 struct sch56xx_bus_context *context;
328 struct regmap *map;
329
330 if (config->reg_bits != 16 && config->val_bits != 8)
331 return ERR_PTR(-EOPNOTSUPP);
332
333 context = kzalloc(sizeof(*context), GFP_KERNEL);
334 if (!context)
335 return ERR_PTR(-ENOMEM);
336
337 context->lock = lock;
338 context->addr = addr;
339
340 map = devm_regmap_init(dev, &sch56xx_bus, context, config);
341 if (IS_ERR(map))
342 kfree(context);
343
344 return map;
345 }
346 EXPORT_SYMBOL(devm_regmap_init_sch56xx);
347
348 /*
349 * Watchdog routines
350 */
351
watchdog_set_timeout(struct watchdog_device * wddev,unsigned int timeout)352 static int watchdog_set_timeout(struct watchdog_device *wddev,
353 unsigned int timeout)
354 {
355 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
356 unsigned int resolution;
357 u8 control;
358 int ret;
359
360 /* 1 second or 60 second resolution? */
361 if (timeout <= 255)
362 resolution = 1;
363 else
364 resolution = 60;
365
366 if (timeout < resolution || timeout > (resolution * 255))
367 return -EINVAL;
368
369 if (resolution == 1)
370 control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
371 else
372 control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
373
374 if (data->watchdog_control != control) {
375 mutex_lock(data->io_lock);
376 ret = sch56xx_write_virtual_reg(data->addr,
377 SCH56XX_REG_WDOG_CONTROL,
378 control);
379 mutex_unlock(data->io_lock);
380 if (ret)
381 return ret;
382
383 data->watchdog_control = control;
384 }
385
386 /*
387 * Remember new timeout value, but do not write as that (re)starts
388 * the watchdog countdown.
389 */
390 data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
391 wddev->timeout = data->watchdog_preset * resolution;
392
393 return 0;
394 }
395
watchdog_start(struct watchdog_device * wddev)396 static int watchdog_start(struct watchdog_device *wddev)
397 {
398 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
399 int ret;
400 u8 val;
401
402 /*
403 * The sch56xx's watchdog cannot really be started / stopped
404 * it is always running, but we can avoid the timer expiring
405 * from causing a system reset by clearing the output enable bit.
406 *
407 * The sch56xx's watchdog will set the watchdog event bit, bit 0
408 * of the second interrupt source register (at base-address + 9),
409 * when the timer expires.
410 *
411 * This will only cause a system reset if the 0-1 flank happens when
412 * output enable is true. Setting output enable after the flank will
413 * not cause a reset, nor will the timer expiring a second time.
414 * This means we must clear the watchdog event bit in case it is set.
415 *
416 * The timer may still be running (after a recent watchdog_stop) and
417 * mere milliseconds away from expiring, so the timer must be reset
418 * first!
419 */
420
421 mutex_lock(data->io_lock);
422
423 /* 1. Reset the watchdog countdown counter */
424 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
425 data->watchdog_preset);
426 if (ret)
427 goto leave;
428
429 /* 2. Enable output */
430 val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
431 ret = sch56xx_write_virtual_reg(data->addr,
432 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
433 if (ret)
434 goto leave;
435
436 data->watchdog_output_enable = val;
437
438 /* 3. Clear the watchdog event bit if set */
439 val = inb(data->addr + 9);
440 if (val & 0x01)
441 outb(0x01, data->addr + 9);
442
443 leave:
444 mutex_unlock(data->io_lock);
445 return ret;
446 }
447
watchdog_trigger(struct watchdog_device * wddev)448 static int watchdog_trigger(struct watchdog_device *wddev)
449 {
450 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
451 int ret;
452
453 /* Reset the watchdog countdown counter */
454 mutex_lock(data->io_lock);
455 ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
456 data->watchdog_preset);
457 mutex_unlock(data->io_lock);
458
459 return ret;
460 }
461
watchdog_stop(struct watchdog_device * wddev)462 static int watchdog_stop(struct watchdog_device *wddev)
463 {
464 struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
465 int ret = 0;
466 u8 val;
467
468 val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
469 mutex_lock(data->io_lock);
470 ret = sch56xx_write_virtual_reg(data->addr,
471 SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
472 mutex_unlock(data->io_lock);
473 if (ret)
474 return ret;
475
476 data->watchdog_output_enable = val;
477 return 0;
478 }
479
480 static const struct watchdog_ops watchdog_ops = {
481 .owner = THIS_MODULE,
482 .start = watchdog_start,
483 .stop = watchdog_stop,
484 .ping = watchdog_trigger,
485 .set_timeout = watchdog_set_timeout,
486 };
487
sch56xx_watchdog_register(struct device * parent,u16 addr,u32 revision,struct mutex * io_lock,int check_enabled)488 void sch56xx_watchdog_register(struct device *parent, u16 addr, u32 revision,
489 struct mutex *io_lock, int check_enabled)
490 {
491 struct sch56xx_watchdog_data *data;
492 int err, control, output_enable;
493
494 /* Cache the watchdog registers */
495 mutex_lock(io_lock);
496 control =
497 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
498 output_enable =
499 sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
500 mutex_unlock(io_lock);
501
502 if (control < 0)
503 return;
504 if (output_enable < 0)
505 return;
506 if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
507 pr_warn("Watchdog not enabled by BIOS, not registering\n");
508 return;
509 }
510
511 data = devm_kzalloc(parent, sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
512 if (!data)
513 return;
514
515 data->addr = addr;
516 data->io_lock = io_lock;
517
518 strscpy(data->wdinfo.identity, "sch56xx watchdog", sizeof(data->wdinfo.identity));
519 data->wdinfo.firmware_version = revision;
520 data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
521 if (!nowayout)
522 data->wdinfo.options |= WDIOF_MAGICCLOSE;
523
524 data->wddev.info = &data->wdinfo;
525 data->wddev.ops = &watchdog_ops;
526 data->wddev.parent = parent;
527 data->wddev.timeout = 60;
528 data->wddev.min_timeout = 1;
529 data->wddev.max_timeout = 255 * 60;
530 watchdog_set_nowayout(&data->wddev, nowayout);
531 if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
532 set_bit(WDOG_HW_RUNNING, &data->wddev.status);
533
534 /* Since the watchdog uses a downcounter there is no register to read
535 the BIOS set timeout from (if any was set at all) ->
536 Choose a preset which will give us a 1 minute timeout */
537 if (control & SCH56XX_WDOG_TIME_BASE_SEC)
538 data->watchdog_preset = 60; /* seconds */
539 else
540 data->watchdog_preset = 1; /* minute */
541
542 data->watchdog_control = control;
543 data->watchdog_output_enable = output_enable;
544
545 watchdog_set_drvdata(&data->wddev, data);
546 err = devm_watchdog_register_device(parent, &data->wddev);
547 if (err) {
548 pr_err("Registering watchdog chardev: %d\n", err);
549 devm_kfree(parent, data);
550 }
551 }
552 EXPORT_SYMBOL(sch56xx_watchdog_register);
553
554 /*
555 * platform dev find, add and remove functions
556 */
557
sch56xx_find(int sioaddr,const char ** name)558 static int __init sch56xx_find(int sioaddr, const char **name)
559 {
560 u8 devid;
561 unsigned short address;
562 int err;
563
564 err = superio_enter(sioaddr);
565 if (err)
566 return err;
567
568 devid = superio_inb(sioaddr, SIO_REG_DEVID);
569 switch (devid) {
570 case SIO_SCH5627_ID:
571 *name = "sch5627";
572 break;
573 case SIO_SCH5636_ID:
574 *name = "sch5636";
575 break;
576 default:
577 pr_debug("Unsupported device id: 0x%02x\n",
578 (unsigned int)devid);
579 err = -ENODEV;
580 goto exit;
581 }
582
583 superio_select(sioaddr, SIO_SCH56XX_LD_EM);
584
585 if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
586 pr_warn("Device not activated\n");
587 err = -ENODEV;
588 goto exit;
589 }
590
591 /*
592 * Warning the order of the low / high byte is the other way around
593 * as on most other superio devices!!
594 */
595 address = superio_inb(sioaddr, SIO_REG_ADDR) |
596 superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
597 if (address == 0) {
598 pr_warn("Base address not set\n");
599 err = -ENODEV;
600 goto exit;
601 }
602 err = address;
603
604 exit:
605 superio_exit(sioaddr);
606 return err;
607 }
608
sch56xx_device_add(int address,const char * name)609 static int __init sch56xx_device_add(int address, const char *name)
610 {
611 struct resource res = {
612 .start = address,
613 .end = address + REGION_LENGTH - 1,
614 .name = name,
615 .flags = IORESOURCE_IO,
616 };
617 int err;
618
619 err = acpi_check_resource_conflict(&res);
620 if (err)
621 return err;
622
623 sch56xx_pdev = platform_device_register_simple(name, -1, &res, 1);
624
625 return PTR_ERR_OR_ZERO(sch56xx_pdev);
626 }
627
sch56xx_init(void)628 static int __init sch56xx_init(void)
629 {
630 int address;
631 const char *name = NULL;
632
633 address = sch56xx_find(0x4e, &name);
634 if (address < 0)
635 address = sch56xx_find(0x2e, &name);
636 if (address < 0)
637 return address;
638
639 return sch56xx_device_add(address, name);
640 }
641
sch56xx_exit(void)642 static void __exit sch56xx_exit(void)
643 {
644 platform_device_unregister(sch56xx_pdev);
645 }
646
647 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
648 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
649 MODULE_LICENSE("GPL");
650
651 module_init(sch56xx_init);
652 module_exit(sch56xx_exit);
653