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/mod_devicetable.h>
11 #include <linux/init.h>
12 #include <linux/platform_device.h>
13 #include <linux/dmi.h>
14 #include <linux/err.h>
15 #include <linux/io.h>
16 #include <linux/acpi.h>
17 #include <linux/delay.h>
18 #include <linux/fs.h>
19 #include <linux/watchdog.h>
20 #include <linux/uaccess.h>
21 #include <linux/slab.h>
22 #include "sch56xx-common.h"
23 
24 static bool ignore_dmi;
25 module_param(ignore_dmi, bool, 0);
26 MODULE_PARM_DESC(ignore_dmi, "Omit DMI check for supported devices (default=0)");
27 
28 static bool nowayout = WATCHDOG_NOWAYOUT;
29 module_param(nowayout, bool, 0);
30 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
31 	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
32 
33 #define SIO_SCH56XX_LD_EM	0x0C	/* Embedded uController Logical Dev */
34 #define SIO_UNLOCK_KEY		0x55	/* Key to enable Super-I/O */
35 #define SIO_LOCK_KEY		0xAA	/* Key to disable Super-I/O */
36 
37 #define SIO_REG_LDSEL		0x07	/* Logical device select */
38 #define SIO_REG_DEVID		0x20	/* Device ID */
39 #define SIO_REG_ENABLE		0x30	/* Logical device enable */
40 #define SIO_REG_ADDR		0x66	/* Logical device address (2 bytes) */
41 
42 #define SIO_SCH5627_ID		0xC6	/* Chipset ID */
43 #define SIO_SCH5636_ID		0xC7	/* Chipset ID */
44 
45 #define REGION_LENGTH		10
46 
47 #define SCH56XX_CMD_READ	0x02
48 #define SCH56XX_CMD_WRITE	0x03
49 
50 /* Watchdog registers */
51 #define SCH56XX_REG_WDOG_PRESET		0x58B
52 #define SCH56XX_REG_WDOG_CONTROL	0x58C
53 #define SCH56XX_WDOG_TIME_BASE_SEC	0x01
54 #define SCH56XX_REG_WDOG_OUTPUT_ENABLE	0x58E
55 #define SCH56XX_WDOG_OUTPUT_ENABLE	0x02
56 
57 struct sch56xx_watchdog_data {
58 	u16 addr;
59 	struct mutex *io_lock;
60 	struct watchdog_info wdinfo;
61 	struct watchdog_device wddev;
62 	u8 watchdog_preset;
63 	u8 watchdog_control;
64 	u8 watchdog_output_enable;
65 };
66 
67 static struct platform_device *sch56xx_pdev;
68 
69 /* Super I/O functions */
70 static inline int superio_inb(int base, int reg)
71 {
72 	outb(reg, base);
73 	return inb(base + 1);
74 }
75 
76 static inline int superio_enter(int base)
77 {
78 	/* Don't step on other drivers' I/O space by accident */
79 	if (!request_muxed_region(base, 2, "sch56xx")) {
80 		pr_err("I/O address 0x%04x already in use\n", base);
81 		return -EBUSY;
82 	}
83 
84 	outb(SIO_UNLOCK_KEY, base);
85 
86 	return 0;
87 }
88 
89 static inline void superio_select(int base, int ld)
90 {
91 	outb(SIO_REG_LDSEL, base);
92 	outb(ld, base + 1);
93 }
94 
95 static inline void superio_exit(int base)
96 {
97 	outb(SIO_LOCK_KEY, base);
98 	release_region(base, 2);
99 }
100 
101 static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
102 {
103 	u8 val;
104 	int i;
105 	/*
106 	 * According to SMSC for the commands we use the maximum time for
107 	 * the EM to respond is 15 ms, but testing shows in practice it
108 	 * responds within 15-32 reads, so we first busy poll, and if
109 	 * that fails sleep a bit and try again until we are way past
110 	 * the 15 ms maximum response time.
111 	 */
112 	const int max_busy_polls = 64;
113 	const int max_lazy_polls = 32;
114 
115 	/* (Optional) Write-Clear the EC to Host Mailbox Register */
116 	val = inb(addr + 1);
117 	outb(val, addr + 1);
118 
119 	/* Set Mailbox Address Pointer to first location in Region 1 */
120 	outb(0x00, addr + 2);
121 	outb(0x80, addr + 3);
122 
123 	/* Write Request Packet Header */
124 	outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
125 	outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
126 	outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
127 
128 	/* Write Value field */
129 	if (cmd == SCH56XX_CMD_WRITE)
130 		outb(v, addr + 4);
131 
132 	/* Write Address field */
133 	outb(reg & 0xff, addr + 6);
134 	outb(reg >> 8, addr + 7);
135 
136 	/* Execute the Random Access Command */
137 	outb(0x01, addr); /* Write 01h to the Host-to-EC register */
138 
139 	/* EM Interface Polling "Algorithm" */
140 	for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
141 		if (i >= max_busy_polls)
142 			usleep_range(1000, 2000);
143 		/* Read Interrupt source Register */
144 		val = inb(addr + 8);
145 		/* Write Clear the interrupt source bits */
146 		if (val)
147 			outb(val, addr + 8);
148 		/* Command Completed ? */
149 		if (val & 0x01)
150 			break;
151 	}
152 	if (i == max_busy_polls + max_lazy_polls) {
153 		pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
154 		       reg, 1);
155 		return -EIO;
156 	}
157 
158 	/*
159 	 * According to SMSC we may need to retry this, but sofar I've always
160 	 * seen this succeed in 1 try.
161 	 */
162 	for (i = 0; i < max_busy_polls; i++) {
163 		/* Read EC-to-Host Register */
164 		val = inb(addr + 1);
165 		/* Command Completed ? */
166 		if (val == 0x01)
167 			break;
168 
169 		if (i == 0)
170 			pr_warn("EC reports: 0x%02x reading virtual register 0x%04hx\n",
171 				(unsigned int)val, reg);
172 	}
173 	if (i == max_busy_polls) {
174 		pr_err("Max retries exceeded reading virtual register 0x%04hx (%d)\n",
175 		       reg, 2);
176 		return -EIO;
177 	}
178 
179 	/*
180 	 * According to the SMSC app note we should now do:
181 	 *
182 	 * Set Mailbox Address Pointer to first location in Region 1 *
183 	 * outb(0x00, addr + 2);
184 	 * outb(0x80, addr + 3);
185 	 *
186 	 * But if we do that things don't work, so let's not.
187 	 */
188 
189 	/* Read Value field */
190 	if (cmd == SCH56XX_CMD_READ)
191 		return inb(addr + 4);
192 
193 	return 0;
194 }
195 
196 int sch56xx_read_virtual_reg(u16 addr, u16 reg)
197 {
198 	return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
199 }
200 EXPORT_SYMBOL(sch56xx_read_virtual_reg);
201 
202 int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
203 {
204 	return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
205 }
206 EXPORT_SYMBOL(sch56xx_write_virtual_reg);
207 
208 int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
209 {
210 	int lsb, msb;
211 
212 	/* Read LSB first, this will cause the matching MSB to be latched */
213 	lsb = sch56xx_read_virtual_reg(addr, reg);
214 	if (lsb < 0)
215 		return lsb;
216 
217 	msb = sch56xx_read_virtual_reg(addr, reg + 1);
218 	if (msb < 0)
219 		return msb;
220 
221 	return lsb | (msb << 8);
222 }
223 EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
224 
225 int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
226 			       int high_nibble)
227 {
228 	int msb, lsn;
229 
230 	/* Read MSB first, this will cause the matching LSN to be latched */
231 	msb = sch56xx_read_virtual_reg(addr, msb_reg);
232 	if (msb < 0)
233 		return msb;
234 
235 	lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
236 	if (lsn < 0)
237 		return lsn;
238 
239 	if (high_nibble)
240 		return (msb << 4) | (lsn >> 4);
241 	else
242 		return (msb << 4) | (lsn & 0x0f);
243 }
244 EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
245 
246 /*
247  * Watchdog routines
248  */
249 
250 static int watchdog_set_timeout(struct watchdog_device *wddev,
251 				unsigned int timeout)
252 {
253 	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
254 	unsigned int resolution;
255 	u8 control;
256 	int ret;
257 
258 	/* 1 second or 60 second resolution? */
259 	if (timeout <= 255)
260 		resolution = 1;
261 	else
262 		resolution = 60;
263 
264 	if (timeout < resolution || timeout > (resolution * 255))
265 		return -EINVAL;
266 
267 	if (resolution == 1)
268 		control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
269 	else
270 		control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
271 
272 	if (data->watchdog_control != control) {
273 		mutex_lock(data->io_lock);
274 		ret = sch56xx_write_virtual_reg(data->addr,
275 						SCH56XX_REG_WDOG_CONTROL,
276 						control);
277 		mutex_unlock(data->io_lock);
278 		if (ret)
279 			return ret;
280 
281 		data->watchdog_control = control;
282 	}
283 
284 	/*
285 	 * Remember new timeout value, but do not write as that (re)starts
286 	 * the watchdog countdown.
287 	 */
288 	data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
289 	wddev->timeout = data->watchdog_preset * resolution;
290 
291 	return 0;
292 }
293 
294 static int watchdog_start(struct watchdog_device *wddev)
295 {
296 	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
297 	int ret;
298 	u8 val;
299 
300 	/*
301 	 * The sch56xx's watchdog cannot really be started / stopped
302 	 * it is always running, but we can avoid the timer expiring
303 	 * from causing a system reset by clearing the output enable bit.
304 	 *
305 	 * The sch56xx's watchdog will set the watchdog event bit, bit 0
306 	 * of the second interrupt source register (at base-address + 9),
307 	 * when the timer expires.
308 	 *
309 	 * This will only cause a system reset if the 0-1 flank happens when
310 	 * output enable is true. Setting output enable after the flank will
311 	 * not cause a reset, nor will the timer expiring a second time.
312 	 * This means we must clear the watchdog event bit in case it is set.
313 	 *
314 	 * The timer may still be running (after a recent watchdog_stop) and
315 	 * mere milliseconds away from expiring, so the timer must be reset
316 	 * first!
317 	 */
318 
319 	mutex_lock(data->io_lock);
320 
321 	/* 1. Reset the watchdog countdown counter */
322 	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
323 					data->watchdog_preset);
324 	if (ret)
325 		goto leave;
326 
327 	/* 2. Enable output */
328 	val = data->watchdog_output_enable | SCH56XX_WDOG_OUTPUT_ENABLE;
329 	ret = sch56xx_write_virtual_reg(data->addr,
330 					SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
331 	if (ret)
332 		goto leave;
333 
334 	data->watchdog_output_enable = val;
335 
336 	/* 3. Clear the watchdog event bit if set */
337 	val = inb(data->addr + 9);
338 	if (val & 0x01)
339 		outb(0x01, data->addr + 9);
340 
341 leave:
342 	mutex_unlock(data->io_lock);
343 	return ret;
344 }
345 
346 static int watchdog_trigger(struct watchdog_device *wddev)
347 {
348 	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
349 	int ret;
350 
351 	/* Reset the watchdog countdown counter */
352 	mutex_lock(data->io_lock);
353 	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
354 					data->watchdog_preset);
355 	mutex_unlock(data->io_lock);
356 
357 	return ret;
358 }
359 
360 static int watchdog_stop(struct watchdog_device *wddev)
361 {
362 	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
363 	int ret = 0;
364 	u8 val;
365 
366 	val = data->watchdog_output_enable & ~SCH56XX_WDOG_OUTPUT_ENABLE;
367 	mutex_lock(data->io_lock);
368 	ret = sch56xx_write_virtual_reg(data->addr,
369 					SCH56XX_REG_WDOG_OUTPUT_ENABLE, val);
370 	mutex_unlock(data->io_lock);
371 	if (ret)
372 		return ret;
373 
374 	data->watchdog_output_enable = val;
375 	return 0;
376 }
377 
378 static const struct watchdog_ops watchdog_ops = {
379 	.owner		= THIS_MODULE,
380 	.start		= watchdog_start,
381 	.stop		= watchdog_stop,
382 	.ping		= watchdog_trigger,
383 	.set_timeout	= watchdog_set_timeout,
384 };
385 
386 void sch56xx_watchdog_register(struct device *parent, u16 addr, u32 revision,
387 			       struct mutex *io_lock, int check_enabled)
388 {
389 	struct sch56xx_watchdog_data *data;
390 	int err, control, output_enable;
391 
392 	/* Cache the watchdog registers */
393 	mutex_lock(io_lock);
394 	control =
395 		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
396 	output_enable =
397 		sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
398 	mutex_unlock(io_lock);
399 
400 	if (control < 0)
401 		return;
402 	if (output_enable < 0)
403 		return;
404 	if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
405 		pr_warn("Watchdog not enabled by BIOS, not registering\n");
406 		return;
407 	}
408 
409 	data = devm_kzalloc(parent, sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
410 	if (!data)
411 		return;
412 
413 	data->addr = addr;
414 	data->io_lock = io_lock;
415 
416 	strscpy(data->wdinfo.identity, "sch56xx watchdog", sizeof(data->wdinfo.identity));
417 	data->wdinfo.firmware_version = revision;
418 	data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
419 	if (!nowayout)
420 		data->wdinfo.options |= WDIOF_MAGICCLOSE;
421 
422 	data->wddev.info = &data->wdinfo;
423 	data->wddev.ops = &watchdog_ops;
424 	data->wddev.parent = parent;
425 	data->wddev.timeout = 60;
426 	data->wddev.min_timeout = 1;
427 	data->wddev.max_timeout = 255 * 60;
428 	watchdog_set_nowayout(&data->wddev, nowayout);
429 	if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
430 		set_bit(WDOG_HW_RUNNING, &data->wddev.status);
431 
432 	/* Since the watchdog uses a downcounter there is no register to read
433 	   the BIOS set timeout from (if any was set at all) ->
434 	   Choose a preset which will give us a 1 minute timeout */
435 	if (control & SCH56XX_WDOG_TIME_BASE_SEC)
436 		data->watchdog_preset = 60; /* seconds */
437 	else
438 		data->watchdog_preset = 1; /* minute */
439 
440 	data->watchdog_control = control;
441 	data->watchdog_output_enable = output_enable;
442 
443 	watchdog_set_drvdata(&data->wddev, data);
444 	err = devm_watchdog_register_device(parent, &data->wddev);
445 	if (err) {
446 		pr_err("Registering watchdog chardev: %d\n", err);
447 		devm_kfree(parent, data);
448 	}
449 }
450 EXPORT_SYMBOL(sch56xx_watchdog_register);
451 
452 /*
453  * platform dev find, add and remove functions
454  */
455 
456 static int __init sch56xx_find(int sioaddr, const char **name)
457 {
458 	u8 devid;
459 	unsigned short address;
460 	int err;
461 
462 	err = superio_enter(sioaddr);
463 	if (err)
464 		return err;
465 
466 	devid = superio_inb(sioaddr, SIO_REG_DEVID);
467 	switch (devid) {
468 	case SIO_SCH5627_ID:
469 		*name = "sch5627";
470 		break;
471 	case SIO_SCH5636_ID:
472 		*name = "sch5636";
473 		break;
474 	default:
475 		pr_debug("Unsupported device id: 0x%02x\n",
476 			 (unsigned int)devid);
477 		err = -ENODEV;
478 		goto exit;
479 	}
480 
481 	superio_select(sioaddr, SIO_SCH56XX_LD_EM);
482 
483 	if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
484 		pr_warn("Device not activated\n");
485 		err = -ENODEV;
486 		goto exit;
487 	}
488 
489 	/*
490 	 * Warning the order of the low / high byte is the other way around
491 	 * as on most other superio devices!!
492 	 */
493 	address = superio_inb(sioaddr, SIO_REG_ADDR) |
494 		   superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
495 	if (address == 0) {
496 		pr_warn("Base address not set\n");
497 		err = -ENODEV;
498 		goto exit;
499 	}
500 	err = address;
501 
502 exit:
503 	superio_exit(sioaddr);
504 	return err;
505 }
506 
507 static int __init sch56xx_device_add(int address, const char *name)
508 {
509 	struct resource res = {
510 		.start	= address,
511 		.end	= address + REGION_LENGTH - 1,
512 		.name	= name,
513 		.flags	= IORESOURCE_IO,
514 	};
515 	int err;
516 
517 	err = acpi_check_resource_conflict(&res);
518 	if (err)
519 		return err;
520 
521 	sch56xx_pdev = platform_device_register_simple(name, -1, &res, 1);
522 
523 	return PTR_ERR_OR_ZERO(sch56xx_pdev);
524 }
525 
526 static const struct dmi_system_id sch56xx_dmi_override_table[] __initconst = {
527 	{
528 		.matches = {
529 			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
530 			DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS W380"),
531 		},
532 	},
533 	{
534 		.matches = {
535 			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
536 			DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO P710"),
537 		},
538 	},
539 	{
540 		.matches = {
541 			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
542 			DMI_MATCH(DMI_PRODUCT_NAME, "ESPRIMO E9900"),
543 		},
544 	},
545 	{ }
546 };
547 
548 /* For autoloading only */
549 static const struct dmi_system_id sch56xx_dmi_table[] __initconst = {
550 	{
551 		.matches = {
552 			DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
553 		},
554 	},
555 	{ }
556 };
557 MODULE_DEVICE_TABLE(dmi, sch56xx_dmi_table);
558 
559 static int __init sch56xx_init(void)
560 {
561 	const char *name = NULL;
562 	int address;
563 
564 	if (!ignore_dmi) {
565 		if (!dmi_check_system(sch56xx_dmi_table))
566 			return -ENODEV;
567 
568 		if (!dmi_check_system(sch56xx_dmi_override_table)) {
569 			/*
570 			 * Some machines like the Esprimo P720 and Esprimo C700 have
571 			 * onboard devices named " Antiope"/" Theseus" instead of
572 			 * "Antiope"/"Theseus", so we need to check for both.
573 			 */
574 			if (!dmi_find_device(DMI_DEV_TYPE_OTHER, "Antiope", NULL) &&
575 			    !dmi_find_device(DMI_DEV_TYPE_OTHER, " Antiope", NULL) &&
576 			    !dmi_find_device(DMI_DEV_TYPE_OTHER, "Theseus", NULL) &&
577 			    !dmi_find_device(DMI_DEV_TYPE_OTHER, " Theseus", NULL))
578 				return -ENODEV;
579 		}
580 	}
581 
582 	/*
583 	 * Some devices like the Esprimo C700 have both onboard devices,
584 	 * so we still have to check manually
585 	 */
586 	address = sch56xx_find(0x4e, &name);
587 	if (address < 0)
588 		address = sch56xx_find(0x2e, &name);
589 	if (address < 0)
590 		return address;
591 
592 	return sch56xx_device_add(address, name);
593 }
594 
595 static void __exit sch56xx_exit(void)
596 {
597 	platform_device_unregister(sch56xx_pdev);
598 }
599 
600 MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
601 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
602 MODULE_LICENSE("GPL");
603 
604 module_init(sch56xx_init);
605 module_exit(sch56xx_exit);
606