xref: /linux/drivers/acpi/ec.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v3)
3  *
4  *  Copyright (C) 2001-2015 Intel Corporation
5  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
6  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
7  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
8  *            2004       Luming Yu <luming.yu@intel.com>
9  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
10  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
11  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
12  *
13  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14  *
15  *  This program is free software; you can redistribute it and/or modify
16  *  it under the terms of the GNU General Public License as published by
17  *  the Free Software Foundation; either version 2 of the License, or (at
18  *  your option) any later version.
19  *
20  *  This program is distributed in the hope that it will be useful, but
21  *  WITHOUT ANY WARRANTY; without even the implied warranty of
22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23  *  General Public License for more details.
24  *
25  *  You should have received a copy of the GNU General Public License along
26  *  with this program; if not, write to the Free Software Foundation, Inc.,
27  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
28  *
29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
30  */
31 
32 /* Uncomment next line to get verbose printout */
33 /* #define DEBUG */
34 #define pr_fmt(fmt) "ACPI : EC: " fmt
35 
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/init.h>
39 #include <linux/types.h>
40 #include <linux/delay.h>
41 #include <linux/interrupt.h>
42 #include <linux/list.h>
43 #include <linux/spinlock.h>
44 #include <linux/slab.h>
45 #include <linux/acpi.h>
46 #include <linux/dmi.h>
47 #include <asm/io.h>
48 
49 #include "internal.h"
50 
51 #define ACPI_EC_CLASS			"embedded_controller"
52 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
53 #define ACPI_EC_FILE_INFO		"info"
54 
55 /* EC status register */
56 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
57 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
58 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
59 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
60 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
61 
62 /* EC commands */
63 enum ec_command {
64 	ACPI_EC_COMMAND_READ = 0x80,
65 	ACPI_EC_COMMAND_WRITE = 0x81,
66 	ACPI_EC_BURST_ENABLE = 0x82,
67 	ACPI_EC_BURST_DISABLE = 0x83,
68 	ACPI_EC_COMMAND_QUERY = 0x84,
69 };
70 
71 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
72 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
73 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
74 #define ACPI_EC_UDELAY_POLL	1000	/* Wait 1ms for EC transaction polling */
75 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
76 					 * when trying to clear the EC */
77 
78 enum {
79 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
80 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
81 					 * OpReg are installed */
82 	EC_FLAGS_STARTED,		/* Driver is started */
83 	EC_FLAGS_STOPPED,		/* Driver is stopped */
84 	EC_FLAGS_COMMAND_STORM,		/* GPE storms occurred to the
85 					 * current command processing */
86 };
87 
88 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
89 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
90 
91 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
92 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
93 module_param(ec_delay, uint, 0644);
94 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
95 
96 /*
97  * If the number of false interrupts per one transaction exceeds
98  * this threshold, will think there is a GPE storm happened and
99  * will disable the GPE for normal transaction.
100  */
101 static unsigned int ec_storm_threshold  __read_mostly = 8;
102 module_param(ec_storm_threshold, uint, 0644);
103 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
104 
105 struct acpi_ec_query_handler {
106 	struct list_head node;
107 	acpi_ec_query_func func;
108 	acpi_handle handle;
109 	void *data;
110 	u8 query_bit;
111 	struct kref kref;
112 };
113 
114 struct transaction {
115 	const u8 *wdata;
116 	u8 *rdata;
117 	unsigned short irq_count;
118 	u8 command;
119 	u8 wi;
120 	u8 ri;
121 	u8 wlen;
122 	u8 rlen;
123 	u8 flags;
124 	unsigned long timestamp;
125 };
126 
127 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
128 static void advance_transaction(struct acpi_ec *ec);
129 
130 struct acpi_ec *boot_ec, *first_ec;
131 EXPORT_SYMBOL(first_ec);
132 
133 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
134 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
135 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
136 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
137 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
138 
139 /* --------------------------------------------------------------------------
140  *                           Device Flags
141  * -------------------------------------------------------------------------- */
142 
143 static bool acpi_ec_started(struct acpi_ec *ec)
144 {
145 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
146 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
147 }
148 
149 static bool acpi_ec_flushed(struct acpi_ec *ec)
150 {
151 	return ec->reference_count == 1;
152 }
153 
154 /* --------------------------------------------------------------------------
155  *                           EC Registers
156  * -------------------------------------------------------------------------- */
157 
158 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
159 {
160 	u8 x = inb(ec->command_addr);
161 
162 	pr_debug("EC_SC(R) = 0x%2.2x "
163 		 "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
164 		 x,
165 		 !!(x & ACPI_EC_FLAG_SCI),
166 		 !!(x & ACPI_EC_FLAG_BURST),
167 		 !!(x & ACPI_EC_FLAG_CMD),
168 		 !!(x & ACPI_EC_FLAG_IBF),
169 		 !!(x & ACPI_EC_FLAG_OBF));
170 	return x;
171 }
172 
173 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
174 {
175 	u8 x = inb(ec->data_addr);
176 
177 	ec->curr->timestamp = jiffies;
178 	pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
179 	return x;
180 }
181 
182 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
183 {
184 	pr_debug("EC_SC(W) = 0x%2.2x\n", command);
185 	outb(command, ec->command_addr);
186 	ec->curr->timestamp = jiffies;
187 }
188 
189 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
190 {
191 	pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
192 	outb(data, ec->data_addr);
193 	ec->curr->timestamp = jiffies;
194 }
195 
196 #ifdef DEBUG
197 static const char *acpi_ec_cmd_string(u8 cmd)
198 {
199 	switch (cmd) {
200 	case 0x80:
201 		return "RD_EC";
202 	case 0x81:
203 		return "WR_EC";
204 	case 0x82:
205 		return "BE_EC";
206 	case 0x83:
207 		return "BD_EC";
208 	case 0x84:
209 		return "QR_EC";
210 	}
211 	return "UNKNOWN";
212 }
213 #else
214 #define acpi_ec_cmd_string(cmd)		"UNDEF"
215 #endif
216 
217 /* --------------------------------------------------------------------------
218  *                           GPE Registers
219  * -------------------------------------------------------------------------- */
220 
221 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
222 {
223 	acpi_event_status gpe_status = 0;
224 
225 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
226 	return (gpe_status & ACPI_EVENT_FLAG_SET) ? true : false;
227 }
228 
229 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
230 {
231 	if (open)
232 		acpi_enable_gpe(NULL, ec->gpe);
233 	else {
234 		BUG_ON(ec->reference_count < 1);
235 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
236 	}
237 	if (acpi_ec_is_gpe_raised(ec)) {
238 		/*
239 		 * On some platforms, EN=1 writes cannot trigger GPE. So
240 		 * software need to manually trigger a pseudo GPE event on
241 		 * EN=1 writes.
242 		 */
243 		pr_debug("***** Polling quirk *****\n");
244 		advance_transaction(ec);
245 	}
246 }
247 
248 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
249 {
250 	if (close)
251 		acpi_disable_gpe(NULL, ec->gpe);
252 	else {
253 		BUG_ON(ec->reference_count < 1);
254 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
255 	}
256 }
257 
258 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
259 {
260 	/*
261 	 * GPE STS is a W1C register, which means:
262 	 * 1. Software can clear it without worrying about clearing other
263 	 *    GPEs' STS bits when the hardware sets them in parallel.
264 	 * 2. As long as software can ensure only clearing it when it is
265 	 *    set, hardware won't set it in parallel.
266 	 * So software can clear GPE in any contexts.
267 	 * Warning: do not move the check into advance_transaction() as the
268 	 * EC commands will be sent without GPE raised.
269 	 */
270 	if (!acpi_ec_is_gpe_raised(ec))
271 		return;
272 	acpi_clear_gpe(NULL, ec->gpe);
273 }
274 
275 /* --------------------------------------------------------------------------
276  *                           Transaction Management
277  * -------------------------------------------------------------------------- */
278 
279 static void acpi_ec_submit_request(struct acpi_ec *ec)
280 {
281 	ec->reference_count++;
282 	if (ec->reference_count == 1)
283 		acpi_ec_enable_gpe(ec, true);
284 }
285 
286 static void acpi_ec_complete_request(struct acpi_ec *ec)
287 {
288 	bool flushed = false;
289 
290 	ec->reference_count--;
291 	if (ec->reference_count == 0)
292 		acpi_ec_disable_gpe(ec, true);
293 	flushed = acpi_ec_flushed(ec);
294 	if (flushed)
295 		wake_up(&ec->wait);
296 }
297 
298 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
299 {
300 	if (!test_bit(flag, &ec->flags)) {
301 		acpi_ec_disable_gpe(ec, false);
302 		pr_debug("+++++ Polling enabled +++++\n");
303 		set_bit(flag, &ec->flags);
304 	}
305 }
306 
307 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
308 {
309 	if (test_bit(flag, &ec->flags)) {
310 		clear_bit(flag, &ec->flags);
311 		acpi_ec_enable_gpe(ec, false);
312 		pr_debug("+++++ Polling disabled +++++\n");
313 	}
314 }
315 
316 /*
317  * acpi_ec_submit_flushable_request() - Increase the reference count unless
318  *                                      the flush operation is not in
319  *                                      progress
320  * @ec: the EC device
321  *
322  * This function must be used before taking a new action that should hold
323  * the reference count.  If this function returns false, then the action
324  * must be discarded or it will prevent the flush operation from being
325  * completed.
326  */
327 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
328 {
329 	if (!acpi_ec_started(ec))
330 		return false;
331 	acpi_ec_submit_request(ec);
332 	return true;
333 }
334 
335 static void acpi_ec_submit_query(struct acpi_ec *ec)
336 {
337 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
338 		pr_debug("***** Event started *****\n");
339 		schedule_work(&ec->work);
340 	}
341 }
342 
343 static void acpi_ec_complete_query(struct acpi_ec *ec)
344 {
345 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
346 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
347 		pr_debug("***** Event stopped *****\n");
348 	}
349 }
350 
351 static int ec_transaction_completed(struct acpi_ec *ec)
352 {
353 	unsigned long flags;
354 	int ret = 0;
355 
356 	spin_lock_irqsave(&ec->lock, flags);
357 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
358 		ret = 1;
359 	spin_unlock_irqrestore(&ec->lock, flags);
360 	return ret;
361 }
362 
363 static void advance_transaction(struct acpi_ec *ec)
364 {
365 	struct transaction *t;
366 	u8 status;
367 	bool wakeup = false;
368 
369 	pr_debug("===== %s (%d) =====\n",
370 		 in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
371 	/*
372 	 * By always clearing STS before handling all indications, we can
373 	 * ensure a hardware STS 0->1 change after this clearing can always
374 	 * trigger a GPE interrupt.
375 	 */
376 	acpi_ec_clear_gpe(ec);
377 	status = acpi_ec_read_status(ec);
378 	t = ec->curr;
379 	if (!t)
380 		goto err;
381 	if (t->flags & ACPI_EC_COMMAND_POLL) {
382 		if (t->wlen > t->wi) {
383 			if ((status & ACPI_EC_FLAG_IBF) == 0)
384 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
385 			else
386 				goto err;
387 		} else if (t->rlen > t->ri) {
388 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
389 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
390 				if (t->rlen == t->ri) {
391 					t->flags |= ACPI_EC_COMMAND_COMPLETE;
392 					if (t->command == ACPI_EC_COMMAND_QUERY)
393 						pr_debug("***** Command(%s) hardware completion *****\n",
394 							 acpi_ec_cmd_string(t->command));
395 					wakeup = true;
396 				}
397 			} else
398 				goto err;
399 		} else if (t->wlen == t->wi &&
400 			   (status & ACPI_EC_FLAG_IBF) == 0) {
401 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
402 			wakeup = true;
403 		}
404 		goto out;
405 	} else {
406 		if (EC_FLAGS_QUERY_HANDSHAKE &&
407 		    !(status & ACPI_EC_FLAG_SCI) &&
408 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
409 			t->flags |= ACPI_EC_COMMAND_POLL;
410 			acpi_ec_complete_query(ec);
411 			t->rdata[t->ri++] = 0x00;
412 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
413 			pr_debug("***** Command(%s) software completion *****\n",
414 				 acpi_ec_cmd_string(t->command));
415 			wakeup = true;
416 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
417 			acpi_ec_write_cmd(ec, t->command);
418 			t->flags |= ACPI_EC_COMMAND_POLL;
419 			acpi_ec_complete_query(ec);
420 		} else
421 			goto err;
422 		goto out;
423 	}
424 err:
425 	/*
426 	 * If SCI bit is set, then don't think it's a false IRQ
427 	 * otherwise will take a not handled IRQ as a false one.
428 	 */
429 	if (!(status & ACPI_EC_FLAG_SCI)) {
430 		if (in_interrupt() && t) {
431 			if (t->irq_count < ec_storm_threshold)
432 				++t->irq_count;
433 			/* Allow triggering on 0 threshold */
434 			if (t->irq_count == ec_storm_threshold)
435 				acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
436 		}
437 	}
438 out:
439 	if (status & ACPI_EC_FLAG_SCI)
440 		acpi_ec_submit_query(ec);
441 	if (wakeup && in_interrupt())
442 		wake_up(&ec->wait);
443 }
444 
445 static void start_transaction(struct acpi_ec *ec)
446 {
447 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
448 	ec->curr->flags = 0;
449 	ec->curr->timestamp = jiffies;
450 	advance_transaction(ec);
451 }
452 
453 static int ec_poll(struct acpi_ec *ec)
454 {
455 	unsigned long flags;
456 	int repeat = 5; /* number of command restarts */
457 
458 	while (repeat--) {
459 		unsigned long delay = jiffies +
460 			msecs_to_jiffies(ec_delay);
461 		unsigned long usecs = ACPI_EC_UDELAY_POLL;
462 		do {
463 			/* don't sleep with disabled interrupts */
464 			if (EC_FLAGS_MSI || irqs_disabled()) {
465 				usecs = ACPI_EC_MSI_UDELAY;
466 				udelay(usecs);
467 				if (ec_transaction_completed(ec))
468 					return 0;
469 			} else {
470 				if (wait_event_timeout(ec->wait,
471 						ec_transaction_completed(ec),
472 						usecs_to_jiffies(usecs)))
473 					return 0;
474 			}
475 			spin_lock_irqsave(&ec->lock, flags);
476 			if (time_after(jiffies,
477 					ec->curr->timestamp +
478 					usecs_to_jiffies(usecs)))
479 				advance_transaction(ec);
480 			spin_unlock_irqrestore(&ec->lock, flags);
481 		} while (time_before(jiffies, delay));
482 		pr_debug("controller reset, restart transaction\n");
483 		spin_lock_irqsave(&ec->lock, flags);
484 		start_transaction(ec);
485 		spin_unlock_irqrestore(&ec->lock, flags);
486 	}
487 	return -ETIME;
488 }
489 
490 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
491 					struct transaction *t)
492 {
493 	unsigned long tmp;
494 	int ret = 0;
495 
496 	if (EC_FLAGS_MSI)
497 		udelay(ACPI_EC_MSI_UDELAY);
498 	/* start transaction */
499 	spin_lock_irqsave(&ec->lock, tmp);
500 	/* Enable GPE for command processing (IBF=0/OBF=1) */
501 	if (!acpi_ec_submit_flushable_request(ec)) {
502 		ret = -EINVAL;
503 		goto unlock;
504 	}
505 	/* following two actions should be kept atomic */
506 	ec->curr = t;
507 	pr_debug("***** Command(%s) started *****\n",
508 		 acpi_ec_cmd_string(t->command));
509 	start_transaction(ec);
510 	spin_unlock_irqrestore(&ec->lock, tmp);
511 	ret = ec_poll(ec);
512 	spin_lock_irqsave(&ec->lock, tmp);
513 	if (t->irq_count == ec_storm_threshold)
514 		acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
515 	pr_debug("***** Command(%s) stopped *****\n",
516 		 acpi_ec_cmd_string(t->command));
517 	ec->curr = NULL;
518 	/* Disable GPE for command processing (IBF=0/OBF=1) */
519 	acpi_ec_complete_request(ec);
520 unlock:
521 	spin_unlock_irqrestore(&ec->lock, tmp);
522 	return ret;
523 }
524 
525 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
526 {
527 	int status;
528 	u32 glk;
529 
530 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
531 		return -EINVAL;
532 	if (t->rdata)
533 		memset(t->rdata, 0, t->rlen);
534 	mutex_lock(&ec->mutex);
535 	if (ec->global_lock) {
536 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
537 		if (ACPI_FAILURE(status)) {
538 			status = -ENODEV;
539 			goto unlock;
540 		}
541 	}
542 
543 	status = acpi_ec_transaction_unlocked(ec, t);
544 
545 	if (test_bit(EC_FLAGS_COMMAND_STORM, &ec->flags))
546 		msleep(1);
547 	if (ec->global_lock)
548 		acpi_release_global_lock(glk);
549 unlock:
550 	mutex_unlock(&ec->mutex);
551 	return status;
552 }
553 
554 static int acpi_ec_burst_enable(struct acpi_ec *ec)
555 {
556 	u8 d;
557 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
558 				.wdata = NULL, .rdata = &d,
559 				.wlen = 0, .rlen = 1};
560 
561 	return acpi_ec_transaction(ec, &t);
562 }
563 
564 static int acpi_ec_burst_disable(struct acpi_ec *ec)
565 {
566 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
567 				.wdata = NULL, .rdata = NULL,
568 				.wlen = 0, .rlen = 0};
569 
570 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
571 				acpi_ec_transaction(ec, &t) : 0;
572 }
573 
574 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
575 {
576 	int result;
577 	u8 d;
578 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
579 				.wdata = &address, .rdata = &d,
580 				.wlen = 1, .rlen = 1};
581 
582 	result = acpi_ec_transaction(ec, &t);
583 	*data = d;
584 	return result;
585 }
586 
587 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
588 {
589 	u8 wdata[2] = { address, data };
590 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
591 				.wdata = wdata, .rdata = NULL,
592 				.wlen = 2, .rlen = 0};
593 
594 	return acpi_ec_transaction(ec, &t);
595 }
596 
597 int ec_read(u8 addr, u8 *val)
598 {
599 	int err;
600 	u8 temp_data;
601 
602 	if (!first_ec)
603 		return -ENODEV;
604 
605 	err = acpi_ec_read(first_ec, addr, &temp_data);
606 
607 	if (!err) {
608 		*val = temp_data;
609 		return 0;
610 	}
611 	return err;
612 }
613 EXPORT_SYMBOL(ec_read);
614 
615 int ec_write(u8 addr, u8 val)
616 {
617 	int err;
618 
619 	if (!first_ec)
620 		return -ENODEV;
621 
622 	err = acpi_ec_write(first_ec, addr, val);
623 
624 	return err;
625 }
626 EXPORT_SYMBOL(ec_write);
627 
628 int ec_transaction(u8 command,
629 		   const u8 *wdata, unsigned wdata_len,
630 		   u8 *rdata, unsigned rdata_len)
631 {
632 	struct transaction t = {.command = command,
633 				.wdata = wdata, .rdata = rdata,
634 				.wlen = wdata_len, .rlen = rdata_len};
635 
636 	if (!first_ec)
637 		return -ENODEV;
638 
639 	return acpi_ec_transaction(first_ec, &t);
640 }
641 EXPORT_SYMBOL(ec_transaction);
642 
643 /* Get the handle to the EC device */
644 acpi_handle ec_get_handle(void)
645 {
646 	if (!first_ec)
647 		return NULL;
648 	return first_ec->handle;
649 }
650 EXPORT_SYMBOL(ec_get_handle);
651 
652 /*
653  * Process _Q events that might have accumulated in the EC.
654  * Run with locked ec mutex.
655  */
656 static void acpi_ec_clear(struct acpi_ec *ec)
657 {
658 	int i, status;
659 	u8 value = 0;
660 
661 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
662 		status = acpi_ec_query(ec, &value);
663 		if (status || !value)
664 			break;
665 	}
666 
667 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
668 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
669 	else
670 		pr_info("%d stale EC events cleared\n", i);
671 }
672 
673 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
674 {
675 	unsigned long flags;
676 
677 	spin_lock_irqsave(&ec->lock, flags);
678 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
679 		pr_debug("+++++ Starting EC +++++\n");
680 		/* Enable GPE for event processing (SCI_EVT=1) */
681 		if (!resuming)
682 			acpi_ec_submit_request(ec);
683 		pr_debug("EC started\n");
684 	}
685 	spin_unlock_irqrestore(&ec->lock, flags);
686 }
687 
688 static bool acpi_ec_stopped(struct acpi_ec *ec)
689 {
690 	unsigned long flags;
691 	bool flushed;
692 
693 	spin_lock_irqsave(&ec->lock, flags);
694 	flushed = acpi_ec_flushed(ec);
695 	spin_unlock_irqrestore(&ec->lock, flags);
696 	return flushed;
697 }
698 
699 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
700 {
701 	unsigned long flags;
702 
703 	spin_lock_irqsave(&ec->lock, flags);
704 	if (acpi_ec_started(ec)) {
705 		pr_debug("+++++ Stopping EC +++++\n");
706 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
707 		spin_unlock_irqrestore(&ec->lock, flags);
708 		wait_event(ec->wait, acpi_ec_stopped(ec));
709 		spin_lock_irqsave(&ec->lock, flags);
710 		/* Disable GPE for event processing (SCI_EVT=1) */
711 		if (!suspending)
712 			acpi_ec_complete_request(ec);
713 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
714 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
715 		pr_debug("EC stopped\n");
716 	}
717 	spin_unlock_irqrestore(&ec->lock, flags);
718 }
719 
720 void acpi_ec_block_transactions(void)
721 {
722 	struct acpi_ec *ec = first_ec;
723 
724 	if (!ec)
725 		return;
726 
727 	mutex_lock(&ec->mutex);
728 	/* Prevent transactions from being carried out */
729 	acpi_ec_stop(ec, true);
730 	mutex_unlock(&ec->mutex);
731 }
732 
733 void acpi_ec_unblock_transactions(void)
734 {
735 	struct acpi_ec *ec = first_ec;
736 
737 	if (!ec)
738 		return;
739 
740 	/* Allow transactions to be carried out again */
741 	acpi_ec_start(ec, true);
742 
743 	if (EC_FLAGS_CLEAR_ON_RESUME)
744 		acpi_ec_clear(ec);
745 }
746 
747 void acpi_ec_unblock_transactions_early(void)
748 {
749 	/*
750 	 * Allow transactions to happen again (this function is called from
751 	 * atomic context during wakeup, so we don't need to acquire the mutex).
752 	 */
753 	if (first_ec)
754 		acpi_ec_start(first_ec, true);
755 }
756 
757 /* --------------------------------------------------------------------------
758                                 Event Management
759    -------------------------------------------------------------------------- */
760 static struct acpi_ec_query_handler *
761 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
762 {
763 	if (handler)
764 		kref_get(&handler->kref);
765 	return handler;
766 }
767 
768 static void acpi_ec_query_handler_release(struct kref *kref)
769 {
770 	struct acpi_ec_query_handler *handler =
771 		container_of(kref, struct acpi_ec_query_handler, kref);
772 
773 	kfree(handler);
774 }
775 
776 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
777 {
778 	kref_put(&handler->kref, acpi_ec_query_handler_release);
779 }
780 
781 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
782 			      acpi_handle handle, acpi_ec_query_func func,
783 			      void *data)
784 {
785 	struct acpi_ec_query_handler *handler =
786 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
787 
788 	if (!handler)
789 		return -ENOMEM;
790 
791 	handler->query_bit = query_bit;
792 	handler->handle = handle;
793 	handler->func = func;
794 	handler->data = data;
795 	mutex_lock(&ec->mutex);
796 	kref_init(&handler->kref);
797 	list_add(&handler->node, &ec->list);
798 	mutex_unlock(&ec->mutex);
799 	return 0;
800 }
801 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
802 
803 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
804 {
805 	struct acpi_ec_query_handler *handler, *tmp;
806 	LIST_HEAD(free_list);
807 
808 	mutex_lock(&ec->mutex);
809 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
810 		if (query_bit == handler->query_bit) {
811 			list_del_init(&handler->node);
812 			list_add(&handler->node, &free_list);
813 		}
814 	}
815 	mutex_unlock(&ec->mutex);
816 	list_for_each_entry(handler, &free_list, node)
817 		acpi_ec_put_query_handler(handler);
818 }
819 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
820 
821 static void acpi_ec_run(void *cxt)
822 {
823 	struct acpi_ec_query_handler *handler = cxt;
824 
825 	if (!handler)
826 		return;
827 	pr_debug("##### Query(0x%02x) started #####\n", handler->query_bit);
828 	if (handler->func)
829 		handler->func(handler->data);
830 	else if (handler->handle)
831 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
832 	pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
833 	acpi_ec_put_query_handler(handler);
834 }
835 
836 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
837 {
838 	u8 value = 0;
839 	int result;
840 	acpi_status status;
841 	struct acpi_ec_query_handler *handler;
842 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
843 				.wdata = NULL, .rdata = &value,
844 				.wlen = 0, .rlen = 1};
845 
846 	/*
847 	 * Query the EC to find out which _Qxx method we need to evaluate.
848 	 * Note that successful completion of the query causes the ACPI_EC_SCI
849 	 * bit to be cleared (and thus clearing the interrupt source).
850 	 */
851 	result = acpi_ec_transaction(ec, &t);
852 	if (result)
853 		return result;
854 	if (data)
855 		*data = value;
856 	if (!value)
857 		return -ENODATA;
858 
859 	mutex_lock(&ec->mutex);
860 	list_for_each_entry(handler, &ec->list, node) {
861 		if (value == handler->query_bit) {
862 			/* have custom handler for this bit */
863 			handler = acpi_ec_get_query_handler(handler);
864 			pr_debug("##### Query(0x%02x) scheduled #####\n",
865 				 handler->query_bit);
866 			status = acpi_os_execute((handler->func) ?
867 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
868 				acpi_ec_run, handler);
869 			if (ACPI_FAILURE(status))
870 				result = -EBUSY;
871 			break;
872 		}
873 	}
874 	mutex_unlock(&ec->mutex);
875 	return result;
876 }
877 
878 static void acpi_ec_gpe_poller(struct work_struct *work)
879 {
880 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
881 
882 	acpi_ec_query(ec, NULL);
883 }
884 
885 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
886 	u32 gpe_number, void *data)
887 {
888 	unsigned long flags;
889 	struct acpi_ec *ec = data;
890 
891 	spin_lock_irqsave(&ec->lock, flags);
892 	advance_transaction(ec);
893 	spin_unlock_irqrestore(&ec->lock, flags);
894 	return ACPI_INTERRUPT_HANDLED;
895 }
896 
897 /* --------------------------------------------------------------------------
898  *                           Address Space Management
899  * -------------------------------------------------------------------------- */
900 
901 static acpi_status
902 acpi_ec_space_handler(u32 function, acpi_physical_address address,
903 		      u32 bits, u64 *value64,
904 		      void *handler_context, void *region_context)
905 {
906 	struct acpi_ec *ec = handler_context;
907 	int result = 0, i, bytes = bits / 8;
908 	u8 *value = (u8 *)value64;
909 
910 	if ((address > 0xFF) || !value || !handler_context)
911 		return AE_BAD_PARAMETER;
912 
913 	if (function != ACPI_READ && function != ACPI_WRITE)
914 		return AE_BAD_PARAMETER;
915 
916 	if (EC_FLAGS_MSI || bits > 8)
917 		acpi_ec_burst_enable(ec);
918 
919 	for (i = 0; i < bytes; ++i, ++address, ++value)
920 		result = (function == ACPI_READ) ?
921 			acpi_ec_read(ec, address, value) :
922 			acpi_ec_write(ec, address, *value);
923 
924 	if (EC_FLAGS_MSI || bits > 8)
925 		acpi_ec_burst_disable(ec);
926 
927 	switch (result) {
928 	case -EINVAL:
929 		return AE_BAD_PARAMETER;
930 	case -ENODEV:
931 		return AE_NOT_FOUND;
932 	case -ETIME:
933 		return AE_TIME;
934 	default:
935 		return AE_OK;
936 	}
937 }
938 
939 /* --------------------------------------------------------------------------
940  *                             Driver Interface
941  * -------------------------------------------------------------------------- */
942 
943 static acpi_status
944 ec_parse_io_ports(struct acpi_resource *resource, void *context);
945 
946 static struct acpi_ec *make_acpi_ec(void)
947 {
948 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
949 
950 	if (!ec)
951 		return NULL;
952 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
953 	mutex_init(&ec->mutex);
954 	init_waitqueue_head(&ec->wait);
955 	INIT_LIST_HEAD(&ec->list);
956 	spin_lock_init(&ec->lock);
957 	INIT_WORK(&ec->work, acpi_ec_gpe_poller);
958 	return ec;
959 }
960 
961 static acpi_status
962 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
963 			       void *context, void **return_value)
964 {
965 	char node_name[5];
966 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
967 	struct acpi_ec *ec = context;
968 	int value = 0;
969 	acpi_status status;
970 
971 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
972 
973 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
974 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
975 	return AE_OK;
976 }
977 
978 static acpi_status
979 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
980 {
981 	acpi_status status;
982 	unsigned long long tmp = 0;
983 	struct acpi_ec *ec = context;
984 
985 	/* clear addr values, ec_parse_io_ports depend on it */
986 	ec->command_addr = ec->data_addr = 0;
987 
988 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
989 				     ec_parse_io_ports, ec);
990 	if (ACPI_FAILURE(status))
991 		return status;
992 
993 	/* Get GPE bit assignment (EC events). */
994 	/* TODO: Add support for _GPE returning a package */
995 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
996 	if (ACPI_FAILURE(status))
997 		return status;
998 	ec->gpe = tmp;
999 	/* Use the global lock for all EC transactions? */
1000 	tmp = 0;
1001 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1002 	ec->global_lock = tmp;
1003 	ec->handle = handle;
1004 	return AE_CTRL_TERMINATE;
1005 }
1006 
1007 static int ec_install_handlers(struct acpi_ec *ec)
1008 {
1009 	acpi_status status;
1010 
1011 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1012 		return 0;
1013 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1014 				  ACPI_GPE_EDGE_TRIGGERED,
1015 				  &acpi_ec_gpe_handler, ec);
1016 	if (ACPI_FAILURE(status))
1017 		return -ENODEV;
1018 
1019 	acpi_ec_start(ec, false);
1020 	status = acpi_install_address_space_handler(ec->handle,
1021 						    ACPI_ADR_SPACE_EC,
1022 						    &acpi_ec_space_handler,
1023 						    NULL, ec);
1024 	if (ACPI_FAILURE(status)) {
1025 		if (status == AE_NOT_FOUND) {
1026 			/*
1027 			 * Maybe OS fails in evaluating the _REG object.
1028 			 * The AE_NOT_FOUND error will be ignored and OS
1029 			 * continue to initialize EC.
1030 			 */
1031 			pr_err("Fail in evaluating the _REG object"
1032 				" of EC device. Broken bios is suspected.\n");
1033 		} else {
1034 			acpi_ec_stop(ec, false);
1035 			acpi_remove_gpe_handler(NULL, ec->gpe,
1036 				&acpi_ec_gpe_handler);
1037 			return -ENODEV;
1038 		}
1039 	}
1040 
1041 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1042 	return 0;
1043 }
1044 
1045 static void ec_remove_handlers(struct acpi_ec *ec)
1046 {
1047 	if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1048 		return;
1049 	acpi_ec_stop(ec, false);
1050 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1051 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1052 		pr_err("failed to remove space handler\n");
1053 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1054 				&acpi_ec_gpe_handler)))
1055 		pr_err("failed to remove gpe handler\n");
1056 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1057 }
1058 
1059 static int acpi_ec_add(struct acpi_device *device)
1060 {
1061 	struct acpi_ec *ec = NULL;
1062 	int ret;
1063 
1064 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1065 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1066 
1067 	/* Check for boot EC */
1068 	if (boot_ec &&
1069 	    (boot_ec->handle == device->handle ||
1070 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
1071 		ec = boot_ec;
1072 		boot_ec = NULL;
1073 	} else {
1074 		ec = make_acpi_ec();
1075 		if (!ec)
1076 			return -ENOMEM;
1077 	}
1078 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
1079 		AE_CTRL_TERMINATE) {
1080 			kfree(ec);
1081 			return -EINVAL;
1082 	}
1083 
1084 	/* Find and register all query methods */
1085 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1086 			    acpi_ec_register_query_methods, NULL, ec, NULL);
1087 
1088 	if (!first_ec)
1089 		first_ec = ec;
1090 	device->driver_data = ec;
1091 
1092 	ret = !!request_region(ec->data_addr, 1, "EC data");
1093 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1094 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1095 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1096 
1097 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1098 			  ec->gpe, ec->command_addr, ec->data_addr);
1099 
1100 	ret = ec_install_handlers(ec);
1101 
1102 	/* EC is fully operational, allow queries */
1103 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
1104 
1105 	/* Clear stale _Q events if hardware might require that */
1106 	if (EC_FLAGS_CLEAR_ON_RESUME)
1107 		acpi_ec_clear(ec);
1108 	return ret;
1109 }
1110 
1111 static int acpi_ec_remove(struct acpi_device *device)
1112 {
1113 	struct acpi_ec *ec;
1114 	struct acpi_ec_query_handler *handler, *tmp;
1115 
1116 	if (!device)
1117 		return -EINVAL;
1118 
1119 	ec = acpi_driver_data(device);
1120 	ec_remove_handlers(ec);
1121 	mutex_lock(&ec->mutex);
1122 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1123 		list_del(&handler->node);
1124 		kfree(handler);
1125 	}
1126 	mutex_unlock(&ec->mutex);
1127 	release_region(ec->data_addr, 1);
1128 	release_region(ec->command_addr, 1);
1129 	device->driver_data = NULL;
1130 	if (ec == first_ec)
1131 		first_ec = NULL;
1132 	kfree(ec);
1133 	return 0;
1134 }
1135 
1136 static acpi_status
1137 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1138 {
1139 	struct acpi_ec *ec = context;
1140 
1141 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1142 		return AE_OK;
1143 
1144 	/*
1145 	 * The first address region returned is the data port, and
1146 	 * the second address region returned is the status/command
1147 	 * port.
1148 	 */
1149 	if (ec->data_addr == 0)
1150 		ec->data_addr = resource->data.io.minimum;
1151 	else if (ec->command_addr == 0)
1152 		ec->command_addr = resource->data.io.minimum;
1153 	else
1154 		return AE_CTRL_TERMINATE;
1155 
1156 	return AE_OK;
1157 }
1158 
1159 int __init acpi_boot_ec_enable(void)
1160 {
1161 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1162 		return 0;
1163 	if (!ec_install_handlers(boot_ec)) {
1164 		first_ec = boot_ec;
1165 		return 0;
1166 	}
1167 	return -EFAULT;
1168 }
1169 
1170 static const struct acpi_device_id ec_device_ids[] = {
1171 	{"PNP0C09", 0},
1172 	{"", 0},
1173 };
1174 
1175 /* Some BIOS do not survive early DSDT scan, skip it */
1176 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1177 {
1178 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
1179 	return 0;
1180 }
1181 
1182 /* ASUStek often supplies us with broken ECDT, validate it */
1183 static int ec_validate_ecdt(const struct dmi_system_id *id)
1184 {
1185 	EC_FLAGS_VALIDATE_ECDT = 1;
1186 	return 0;
1187 }
1188 
1189 /* MSI EC needs special treatment, enable it */
1190 static int ec_flag_msi(const struct dmi_system_id *id)
1191 {
1192 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
1193 	EC_FLAGS_MSI = 1;
1194 	EC_FLAGS_VALIDATE_ECDT = 1;
1195 	return 0;
1196 }
1197 
1198 /*
1199  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
1200  * the GPE storm threshold back to 20
1201  */
1202 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
1203 {
1204 	pr_debug("Setting the EC GPE storm threshold to 20\n");
1205 	ec_storm_threshold  = 20;
1206 	return 0;
1207 }
1208 
1209 /*
1210  * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
1211  * which case, we complete the QR_EC without issuing it to the firmware.
1212  * https://bugzilla.kernel.org/show_bug.cgi?id=86211
1213  */
1214 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1215 {
1216 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1217 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1218 	return 0;
1219 }
1220 
1221 /*
1222  * On some hardware it is necessary to clear events accumulated by the EC during
1223  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1224  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1225  *
1226  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1227  *
1228  * Ideally, the EC should also be instructed NOT to accumulate events during
1229  * sleep (which Windows seems to do somehow), but the interface to control this
1230  * behaviour is not known at this time.
1231  *
1232  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1233  * however it is very likely that other Samsung models are affected.
1234  *
1235  * On systems which don't accumulate _Q events during sleep, this extra check
1236  * should be harmless.
1237  */
1238 static int ec_clear_on_resume(const struct dmi_system_id *id)
1239 {
1240 	pr_debug("Detected system needing EC poll on resume.\n");
1241 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1242 	return 0;
1243 }
1244 
1245 static struct dmi_system_id ec_dmi_table[] __initdata = {
1246 	{
1247 	ec_skip_dsdt_scan, "Compal JFL92", {
1248 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1249 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1250 	{
1251 	ec_flag_msi, "MSI hardware", {
1252 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1253 	{
1254 	ec_flag_msi, "MSI hardware", {
1255 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
1256 	{
1257 	ec_flag_msi, "MSI hardware", {
1258 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1259 	{
1260 	ec_flag_msi, "MSI hardware", {
1261 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1262 	{
1263 	ec_flag_msi, "Quanta hardware", {
1264 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1265 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1266 	{
1267 	ec_flag_msi, "Quanta hardware", {
1268 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1269 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1270 	{
1271 	ec_flag_msi, "Clevo W350etq", {
1272 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
1273 	DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
1274 	{
1275 	ec_validate_ecdt, "ASUS hardware", {
1276 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1277 	{
1278 	ec_validate_ecdt, "ASUS hardware", {
1279 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1280 	{
1281 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1282 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1283 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1284 	{
1285 	ec_skip_dsdt_scan, "HP Folio 13", {
1286 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1287 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1288 	{
1289 	ec_validate_ecdt, "ASUS hardware", {
1290 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1291 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1292 	{
1293 	ec_clear_on_resume, "Samsung hardware", {
1294 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1295 	{
1296 	ec_flag_query_handshake, "Acer hardware", {
1297 	DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
1298 	{},
1299 };
1300 
1301 int __init acpi_ec_ecdt_probe(void)
1302 {
1303 	acpi_status status;
1304 	struct acpi_ec *saved_ec = NULL;
1305 	struct acpi_table_ecdt *ecdt_ptr;
1306 
1307 	boot_ec = make_acpi_ec();
1308 	if (!boot_ec)
1309 		return -ENOMEM;
1310 	/*
1311 	 * Generate a boot ec context
1312 	 */
1313 	dmi_check_system(ec_dmi_table);
1314 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1315 				(struct acpi_table_header **)&ecdt_ptr);
1316 	if (ACPI_SUCCESS(status)) {
1317 		pr_info("EC description table is found, configuring boot EC\n");
1318 		boot_ec->command_addr = ecdt_ptr->control.address;
1319 		boot_ec->data_addr = ecdt_ptr->data.address;
1320 		boot_ec->gpe = ecdt_ptr->gpe;
1321 		boot_ec->handle = ACPI_ROOT_OBJECT;
1322 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1323 				&boot_ec->handle);
1324 		/* Don't trust ECDT, which comes from ASUSTek */
1325 		if (!EC_FLAGS_VALIDATE_ECDT)
1326 			goto install;
1327 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1328 		if (!saved_ec)
1329 			return -ENOMEM;
1330 	/* fall through */
1331 	}
1332 
1333 	if (EC_FLAGS_SKIP_DSDT_SCAN) {
1334 		kfree(saved_ec);
1335 		return -ENODEV;
1336 	}
1337 
1338 	/* This workaround is needed only on some broken machines,
1339 	 * which require early EC, but fail to provide ECDT */
1340 	pr_debug("Look up EC in DSDT\n");
1341 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1342 					boot_ec, NULL);
1343 	/* Check that acpi_get_devices actually find something */
1344 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1345 		goto error;
1346 	if (saved_ec) {
1347 		/* try to find good ECDT from ASUSTek */
1348 		if (saved_ec->command_addr != boot_ec->command_addr ||
1349 		    saved_ec->data_addr != boot_ec->data_addr ||
1350 		    saved_ec->gpe != boot_ec->gpe ||
1351 		    saved_ec->handle != boot_ec->handle)
1352 			pr_info("ASUSTek keeps feeding us with broken "
1353 			"ECDT tables, which are very hard to workaround. "
1354 			"Trying to use DSDT EC info instead. Please send "
1355 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1356 		kfree(saved_ec);
1357 		saved_ec = NULL;
1358 	} else {
1359 		/* We really need to limit this workaround, the only ASUS,
1360 		* which needs it, has fake EC._INI method, so use it as flag.
1361 		* Keep boot_ec struct as it will be needed soon.
1362 		*/
1363 		if (!dmi_name_in_vendors("ASUS") ||
1364 		    !acpi_has_method(boot_ec->handle, "_INI"))
1365 			return -ENODEV;
1366 	}
1367 install:
1368 	if (!ec_install_handlers(boot_ec)) {
1369 		first_ec = boot_ec;
1370 		return 0;
1371 	}
1372 error:
1373 	kfree(boot_ec);
1374 	kfree(saved_ec);
1375 	boot_ec = NULL;
1376 	return -ENODEV;
1377 }
1378 
1379 static struct acpi_driver acpi_ec_driver = {
1380 	.name = "ec",
1381 	.class = ACPI_EC_CLASS,
1382 	.ids = ec_device_ids,
1383 	.ops = {
1384 		.add = acpi_ec_add,
1385 		.remove = acpi_ec_remove,
1386 		},
1387 };
1388 
1389 int __init acpi_ec_init(void)
1390 {
1391 	int result = 0;
1392 
1393 	/* Now register the driver for the EC */
1394 	result = acpi_bus_register_driver(&acpi_ec_driver);
1395 	if (result < 0)
1396 		return -ENODEV;
1397 
1398 	return result;
1399 }
1400 
1401 /* EC driver currently not unloadable */
1402 #if 0
1403 static void __exit acpi_ec_exit(void)
1404 {
1405 
1406 	acpi_bus_unregister_driver(&acpi_ec_driver);
1407 }
1408 #endif	/* 0 */
1409