xref: /linux/drivers/acpi/ec.c (revision 04303f8ec14269b0ea2553863553bc7eaadca1f8)
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 DEBUG_REF 0
35 #define pr_fmt(fmt) "ACPI : EC: " fmt
36 
37 #include <linux/kernel.h>
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/types.h>
41 #include <linux/delay.h>
42 #include <linux/interrupt.h>
43 #include <linux/list.h>
44 #include <linux/spinlock.h>
45 #include <linux/slab.h>
46 #include <linux/acpi.h>
47 #include <linux/dmi.h>
48 #include <asm/io.h>
49 
50 #include "internal.h"
51 
52 #define ACPI_EC_CLASS			"embedded_controller"
53 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
54 #define ACPI_EC_FILE_INFO		"info"
55 
56 /* EC status register */
57 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
58 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
59 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
60 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
61 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
62 
63 /* EC commands */
64 enum ec_command {
65 	ACPI_EC_COMMAND_READ = 0x80,
66 	ACPI_EC_COMMAND_WRITE = 0x81,
67 	ACPI_EC_BURST_ENABLE = 0x82,
68 	ACPI_EC_BURST_DISABLE = 0x83,
69 	ACPI_EC_COMMAND_QUERY = 0x84,
70 };
71 
72 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
73 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
74 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
75 #define ACPI_EC_UDELAY_POLL	1000	/* Wait 1ms for EC transaction polling */
76 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
77 					 * when trying to clear the EC */
78 
79 enum {
80 	EC_FLAGS_EVENT_ENABLED,		/* Event is enabled */
81 	EC_FLAGS_EVENT_PENDING,		/* Event is pending */
82 	EC_FLAGS_EVENT_DETECTED,	/* Event is detected */
83 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
84 					 * OpReg are installed */
85 	EC_FLAGS_STARTED,		/* Driver is started */
86 	EC_FLAGS_STOPPED,		/* Driver is stopped */
87 	EC_FLAGS_COMMAND_STORM,		/* GPE storms occurred to the
88 					 * current command processing */
89 };
90 
91 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
92 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
93 
94 #define ec_debug_ref(ec, fmt, ...)					\
95 	do {								\
96 		if (DEBUG_REF)						\
97 			pr_debug("%lu: " fmt, ec->reference_count,	\
98 				 ## __VA_ARGS__);			\
99 	} while (0)
100 
101 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
102 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
103 module_param(ec_delay, uint, 0644);
104 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
105 
106 /*
107  * If the number of false interrupts per one transaction exceeds
108  * this threshold, will think there is a GPE storm happened and
109  * will disable the GPE for normal transaction.
110  */
111 static unsigned int ec_storm_threshold  __read_mostly = 8;
112 module_param(ec_storm_threshold, uint, 0644);
113 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
114 
115 struct acpi_ec_query_handler {
116 	struct list_head node;
117 	acpi_ec_query_func func;
118 	acpi_handle handle;
119 	void *data;
120 	u8 query_bit;
121 	struct kref kref;
122 };
123 
124 struct transaction {
125 	const u8 *wdata;
126 	u8 *rdata;
127 	unsigned short irq_count;
128 	u8 command;
129 	u8 wi;
130 	u8 ri;
131 	u8 wlen;
132 	u8 rlen;
133 	u8 flags;
134 	unsigned long timestamp;
135 };
136 
137 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
138 static void advance_transaction(struct acpi_ec *ec);
139 
140 struct acpi_ec *boot_ec, *first_ec;
141 EXPORT_SYMBOL(first_ec);
142 
143 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
144 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
145 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
146 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
147 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
148 
149 /* --------------------------------------------------------------------------
150  *                           Device Flags
151  * -------------------------------------------------------------------------- */
152 
153 static bool acpi_ec_started(struct acpi_ec *ec)
154 {
155 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
156 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
157 }
158 
159 static bool acpi_ec_flushed(struct acpi_ec *ec)
160 {
161 	return ec->reference_count == 1;
162 }
163 
164 static bool acpi_ec_has_pending_event(struct acpi_ec *ec)
165 {
166 	return test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
167 	       test_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
168 }
169 
170 /* --------------------------------------------------------------------------
171  *                           EC Registers
172  * -------------------------------------------------------------------------- */
173 
174 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
175 {
176 	u8 x = inb(ec->command_addr);
177 
178 	pr_debug("EC_SC(R) = 0x%2.2x "
179 		 "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
180 		 x,
181 		 !!(x & ACPI_EC_FLAG_SCI),
182 		 !!(x & ACPI_EC_FLAG_BURST),
183 		 !!(x & ACPI_EC_FLAG_CMD),
184 		 !!(x & ACPI_EC_FLAG_IBF),
185 		 !!(x & ACPI_EC_FLAG_OBF));
186 	return x;
187 }
188 
189 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
190 {
191 	u8 x = inb(ec->data_addr);
192 
193 	ec->curr->timestamp = jiffies;
194 	pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
195 	return x;
196 }
197 
198 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
199 {
200 	pr_debug("EC_SC(W) = 0x%2.2x\n", command);
201 	outb(command, ec->command_addr);
202 	ec->curr->timestamp = jiffies;
203 }
204 
205 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
206 {
207 	pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
208 	outb(data, ec->data_addr);
209 	ec->curr->timestamp = jiffies;
210 }
211 
212 #ifdef DEBUG
213 static const char *acpi_ec_cmd_string(u8 cmd)
214 {
215 	switch (cmd) {
216 	case 0x80:
217 		return "RD_EC";
218 	case 0x81:
219 		return "WR_EC";
220 	case 0x82:
221 		return "BE_EC";
222 	case 0x83:
223 		return "BD_EC";
224 	case 0x84:
225 		return "QR_EC";
226 	}
227 	return "UNKNOWN";
228 }
229 #else
230 #define acpi_ec_cmd_string(cmd)		"UNDEF"
231 #endif
232 
233 /* --------------------------------------------------------------------------
234  *                           GPE Registers
235  * -------------------------------------------------------------------------- */
236 
237 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
238 {
239 	acpi_event_status gpe_status = 0;
240 
241 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
242 	return (gpe_status & ACPI_EVENT_FLAG_SET) ? true : false;
243 }
244 
245 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
246 {
247 	if (open)
248 		acpi_enable_gpe(NULL, ec->gpe);
249 	else {
250 		BUG_ON(ec->reference_count < 1);
251 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
252 	}
253 	if (acpi_ec_is_gpe_raised(ec)) {
254 		/*
255 		 * On some platforms, EN=1 writes cannot trigger GPE. So
256 		 * software need to manually trigger a pseudo GPE event on
257 		 * EN=1 writes.
258 		 */
259 		pr_debug("***** Polling quirk *****\n");
260 		advance_transaction(ec);
261 	}
262 }
263 
264 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
265 {
266 	if (close)
267 		acpi_disable_gpe(NULL, ec->gpe);
268 	else {
269 		BUG_ON(ec->reference_count < 1);
270 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
271 	}
272 }
273 
274 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
275 {
276 	/*
277 	 * GPE STS is a W1C register, which means:
278 	 * 1. Software can clear it without worrying about clearing other
279 	 *    GPEs' STS bits when the hardware sets them in parallel.
280 	 * 2. As long as software can ensure only clearing it when it is
281 	 *    set, hardware won't set it in parallel.
282 	 * So software can clear GPE in any contexts.
283 	 * Warning: do not move the check into advance_transaction() as the
284 	 * EC commands will be sent without GPE raised.
285 	 */
286 	if (!acpi_ec_is_gpe_raised(ec))
287 		return;
288 	acpi_clear_gpe(NULL, ec->gpe);
289 }
290 
291 /* --------------------------------------------------------------------------
292  *                           Transaction Management
293  * -------------------------------------------------------------------------- */
294 
295 static void acpi_ec_submit_request(struct acpi_ec *ec)
296 {
297 	ec->reference_count++;
298 	if (ec->reference_count == 1)
299 		acpi_ec_enable_gpe(ec, true);
300 }
301 
302 static void acpi_ec_complete_request(struct acpi_ec *ec)
303 {
304 	bool flushed = false;
305 
306 	ec->reference_count--;
307 	if (ec->reference_count == 0)
308 		acpi_ec_disable_gpe(ec, true);
309 	flushed = acpi_ec_flushed(ec);
310 	if (flushed)
311 		wake_up(&ec->wait);
312 }
313 
314 static void acpi_ec_set_storm(struct acpi_ec *ec, u8 flag)
315 {
316 	if (!test_bit(flag, &ec->flags)) {
317 		acpi_ec_disable_gpe(ec, false);
318 		pr_debug("+++++ Polling enabled +++++\n");
319 		set_bit(flag, &ec->flags);
320 	}
321 }
322 
323 static void acpi_ec_clear_storm(struct acpi_ec *ec, u8 flag)
324 {
325 	if (test_bit(flag, &ec->flags)) {
326 		clear_bit(flag, &ec->flags);
327 		acpi_ec_enable_gpe(ec, false);
328 		pr_debug("+++++ Polling disabled +++++\n");
329 	}
330 }
331 
332 /*
333  * acpi_ec_submit_flushable_request() - Increase the reference count unless
334  *                                      the flush operation is not in
335  *                                      progress
336  * @ec: the EC device
337  * @allow_event: whether event should be handled
338  *
339  * This function must be used before taking a new action that should hold
340  * the reference count.  If this function returns false, then the action
341  * must be discarded or it will prevent the flush operation from being
342  * completed.
343  *
344  * During flushing, QR_EC command need to pass this check when there is a
345  * pending event, so that the reference count held for the pending event
346  * can be decreased by the completion of the QR_EC command.
347  */
348 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec,
349 					     bool allow_event)
350 {
351 	if (!acpi_ec_started(ec)) {
352 		if (!allow_event || !acpi_ec_has_pending_event(ec))
353 			return false;
354 	}
355 	acpi_ec_submit_request(ec);
356 	return true;
357 }
358 
359 static void acpi_ec_submit_event(struct acpi_ec *ec)
360 {
361 	if (!test_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags) ||
362 	    !test_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags))
363 		return;
364 	/* Hold reference for pending event */
365 	if (!acpi_ec_submit_flushable_request(ec, true))
366 		return;
367 	ec_debug_ref(ec, "Increase event\n");
368 	if (!test_and_set_bit(EC_FLAGS_EVENT_PENDING, &ec->flags)) {
369 		pr_debug("***** Event query started *****\n");
370 		schedule_work(&ec->work);
371 		return;
372 	}
373 	acpi_ec_complete_request(ec);
374 	ec_debug_ref(ec, "Decrease event\n");
375 }
376 
377 static void acpi_ec_complete_event(struct acpi_ec *ec)
378 {
379 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
380 		clear_bit(EC_FLAGS_EVENT_PENDING, &ec->flags);
381 		pr_debug("***** Event query stopped *****\n");
382 		/* Unhold reference for pending event */
383 		acpi_ec_complete_request(ec);
384 		ec_debug_ref(ec, "Decrease event\n");
385 		/* Check if there is another SCI_EVT detected */
386 		acpi_ec_submit_event(ec);
387 	}
388 }
389 
390 static void acpi_ec_submit_detection(struct acpi_ec *ec)
391 {
392 	/* Hold reference for query submission */
393 	if (!acpi_ec_submit_flushable_request(ec, false))
394 		return;
395 	ec_debug_ref(ec, "Increase query\n");
396 	if (!test_and_set_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags)) {
397 		pr_debug("***** Event detection blocked *****\n");
398 		acpi_ec_submit_event(ec);
399 		return;
400 	}
401 	acpi_ec_complete_request(ec);
402 	ec_debug_ref(ec, "Decrease query\n");
403 }
404 
405 static void acpi_ec_complete_detection(struct acpi_ec *ec)
406 {
407 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
408 		clear_bit(EC_FLAGS_EVENT_DETECTED, &ec->flags);
409 		pr_debug("***** Event detetion unblocked *****\n");
410 		/* Unhold reference for query submission */
411 		acpi_ec_complete_request(ec);
412 		ec_debug_ref(ec, "Decrease query\n");
413 	}
414 }
415 
416 static void acpi_ec_enable_event(struct acpi_ec *ec)
417 {
418 	unsigned long flags;
419 
420 	spin_lock_irqsave(&ec->lock, flags);
421 	set_bit(EC_FLAGS_EVENT_ENABLED, &ec->flags);
422 	/*
423 	 * An event may be pending even with SCI_EVT=0, so QR_EC should
424 	 * always be issued right after started.
425 	 */
426 	acpi_ec_submit_detection(ec);
427 	spin_unlock_irqrestore(&ec->lock, flags);
428 }
429 
430 static int ec_transaction_completed(struct acpi_ec *ec)
431 {
432 	unsigned long flags;
433 	int ret = 0;
434 
435 	spin_lock_irqsave(&ec->lock, flags);
436 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
437 		ret = 1;
438 	spin_unlock_irqrestore(&ec->lock, flags);
439 	return ret;
440 }
441 
442 static void advance_transaction(struct acpi_ec *ec)
443 {
444 	struct transaction *t;
445 	u8 status;
446 	bool wakeup = false;
447 
448 	pr_debug("===== %s (%d) =====\n",
449 		 in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
450 	/*
451 	 * By always clearing STS before handling all indications, we can
452 	 * ensure a hardware STS 0->1 change after this clearing can always
453 	 * trigger a GPE interrupt.
454 	 */
455 	acpi_ec_clear_gpe(ec);
456 	status = acpi_ec_read_status(ec);
457 	t = ec->curr;
458 	if (!t)
459 		goto err;
460 	if (t->flags & ACPI_EC_COMMAND_POLL) {
461 		if (t->wlen > t->wi) {
462 			if ((status & ACPI_EC_FLAG_IBF) == 0)
463 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
464 			else
465 				goto err;
466 		} else if (t->rlen > t->ri) {
467 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
468 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
469 				if (t->rlen == t->ri) {
470 					t->flags |= ACPI_EC_COMMAND_COMPLETE;
471 					acpi_ec_complete_event(ec);
472 					if (t->command == ACPI_EC_COMMAND_QUERY)
473 						pr_debug("***** Command(%s) hardware completion *****\n",
474 							 acpi_ec_cmd_string(t->command));
475 					wakeup = true;
476 				}
477 			} else
478 				goto err;
479 		} else if (t->wlen == t->wi &&
480 			   (status & ACPI_EC_FLAG_IBF) == 0) {
481 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
482 			acpi_ec_complete_event(ec);
483 			wakeup = true;
484 		}
485 		goto out;
486 	} else {
487 		if (EC_FLAGS_QUERY_HANDSHAKE &&
488 		    !(status & ACPI_EC_FLAG_SCI) &&
489 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
490 			t->flags |= ACPI_EC_COMMAND_POLL;
491 			acpi_ec_complete_detection(ec);
492 			t->rdata[t->ri++] = 0x00;
493 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
494 			acpi_ec_complete_event(ec);
495 			pr_debug("***** Command(%s) software completion *****\n",
496 				 acpi_ec_cmd_string(t->command));
497 			wakeup = true;
498 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
499 			acpi_ec_write_cmd(ec, t->command);
500 			t->flags |= ACPI_EC_COMMAND_POLL;
501 			acpi_ec_complete_detection(ec);
502 		} else
503 			goto err;
504 		goto out;
505 	}
506 err:
507 	/*
508 	 * If SCI bit is set, then don't think it's a false IRQ
509 	 * otherwise will take a not handled IRQ as a false one.
510 	 */
511 	if (!(status & ACPI_EC_FLAG_SCI)) {
512 		if (in_interrupt() && t) {
513 			if (t->irq_count < ec_storm_threshold)
514 				++t->irq_count;
515 			/* Allow triggering on 0 threshold */
516 			if (t->irq_count == ec_storm_threshold)
517 				acpi_ec_set_storm(ec, EC_FLAGS_COMMAND_STORM);
518 		}
519 	}
520 out:
521 	if (status & ACPI_EC_FLAG_SCI)
522 		acpi_ec_submit_detection(ec);
523 	if (wakeup && in_interrupt())
524 		wake_up(&ec->wait);
525 }
526 
527 static void start_transaction(struct acpi_ec *ec)
528 {
529 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
530 	ec->curr->flags = 0;
531 	ec->curr->timestamp = jiffies;
532 	advance_transaction(ec);
533 }
534 
535 static int ec_poll(struct acpi_ec *ec)
536 {
537 	unsigned long flags;
538 	int repeat = 5; /* number of command restarts */
539 
540 	while (repeat--) {
541 		unsigned long delay = jiffies +
542 			msecs_to_jiffies(ec_delay);
543 		unsigned long usecs = ACPI_EC_UDELAY_POLL;
544 		do {
545 			/* don't sleep with disabled interrupts */
546 			if (EC_FLAGS_MSI || irqs_disabled()) {
547 				usecs = ACPI_EC_MSI_UDELAY;
548 				udelay(usecs);
549 				if (ec_transaction_completed(ec))
550 					return 0;
551 			} else {
552 				if (wait_event_timeout(ec->wait,
553 						ec_transaction_completed(ec),
554 						usecs_to_jiffies(usecs)))
555 					return 0;
556 			}
557 			spin_lock_irqsave(&ec->lock, flags);
558 			if (time_after(jiffies,
559 					ec->curr->timestamp +
560 					usecs_to_jiffies(usecs)))
561 				advance_transaction(ec);
562 			spin_unlock_irqrestore(&ec->lock, flags);
563 		} while (time_before(jiffies, delay));
564 		pr_debug("controller reset, restart transaction\n");
565 		spin_lock_irqsave(&ec->lock, flags);
566 		start_transaction(ec);
567 		spin_unlock_irqrestore(&ec->lock, flags);
568 	}
569 	return -ETIME;
570 }
571 
572 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
573 					struct transaction *t)
574 {
575 	unsigned long tmp;
576 	int ret = 0;
577 
578 	if (EC_FLAGS_MSI)
579 		udelay(ACPI_EC_MSI_UDELAY);
580 	/* start transaction */
581 	spin_lock_irqsave(&ec->lock, tmp);
582 	/* Enable GPE for command processing (IBF=0/OBF=1) */
583 	if (!acpi_ec_submit_flushable_request(ec, true)) {
584 		ret = -EINVAL;
585 		goto unlock;
586 	}
587 	ec_debug_ref(ec, "Increase command\n");
588 	/* following two actions should be kept atomic */
589 	ec->curr = t;
590 	pr_debug("***** Command(%s) started *****\n",
591 		 acpi_ec_cmd_string(t->command));
592 	start_transaction(ec);
593 	spin_unlock_irqrestore(&ec->lock, tmp);
594 	ret = ec_poll(ec);
595 	spin_lock_irqsave(&ec->lock, tmp);
596 	if (t->irq_count == ec_storm_threshold)
597 		acpi_ec_clear_storm(ec, EC_FLAGS_COMMAND_STORM);
598 	pr_debug("***** Command(%s) stopped *****\n",
599 		 acpi_ec_cmd_string(t->command));
600 	ec->curr = NULL;
601 	/* Disable GPE for command processing (IBF=0/OBF=1) */
602 	acpi_ec_complete_request(ec);
603 	ec_debug_ref(ec, "Decrease command\n");
604 unlock:
605 	spin_unlock_irqrestore(&ec->lock, tmp);
606 	return ret;
607 }
608 
609 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
610 {
611 	int status;
612 	u32 glk;
613 
614 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
615 		return -EINVAL;
616 	if (t->rdata)
617 		memset(t->rdata, 0, t->rlen);
618 	mutex_lock(&ec->mutex);
619 	if (ec->global_lock) {
620 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
621 		if (ACPI_FAILURE(status)) {
622 			status = -ENODEV;
623 			goto unlock;
624 		}
625 	}
626 
627 	status = acpi_ec_transaction_unlocked(ec, t);
628 
629 	if (test_bit(EC_FLAGS_COMMAND_STORM, &ec->flags))
630 		msleep(1);
631 	if (ec->global_lock)
632 		acpi_release_global_lock(glk);
633 unlock:
634 	mutex_unlock(&ec->mutex);
635 	return status;
636 }
637 
638 static int acpi_ec_burst_enable(struct acpi_ec *ec)
639 {
640 	u8 d;
641 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
642 				.wdata = NULL, .rdata = &d,
643 				.wlen = 0, .rlen = 1};
644 
645 	return acpi_ec_transaction(ec, &t);
646 }
647 
648 static int acpi_ec_burst_disable(struct acpi_ec *ec)
649 {
650 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
651 				.wdata = NULL, .rdata = NULL,
652 				.wlen = 0, .rlen = 0};
653 
654 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
655 				acpi_ec_transaction(ec, &t) : 0;
656 }
657 
658 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
659 {
660 	int result;
661 	u8 d;
662 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
663 				.wdata = &address, .rdata = &d,
664 				.wlen = 1, .rlen = 1};
665 
666 	result = acpi_ec_transaction(ec, &t);
667 	*data = d;
668 	return result;
669 }
670 
671 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
672 {
673 	u8 wdata[2] = { address, data };
674 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
675 				.wdata = wdata, .rdata = NULL,
676 				.wlen = 2, .rlen = 0};
677 
678 	return acpi_ec_transaction(ec, &t);
679 }
680 
681 int ec_read(u8 addr, u8 *val)
682 {
683 	int err;
684 	u8 temp_data;
685 
686 	if (!first_ec)
687 		return -ENODEV;
688 
689 	err = acpi_ec_read(first_ec, addr, &temp_data);
690 
691 	if (!err) {
692 		*val = temp_data;
693 		return 0;
694 	}
695 	return err;
696 }
697 EXPORT_SYMBOL(ec_read);
698 
699 int ec_write(u8 addr, u8 val)
700 {
701 	int err;
702 
703 	if (!first_ec)
704 		return -ENODEV;
705 
706 	err = acpi_ec_write(first_ec, addr, val);
707 
708 	return err;
709 }
710 EXPORT_SYMBOL(ec_write);
711 
712 int ec_transaction(u8 command,
713 		   const u8 *wdata, unsigned wdata_len,
714 		   u8 *rdata, unsigned rdata_len)
715 {
716 	struct transaction t = {.command = command,
717 				.wdata = wdata, .rdata = rdata,
718 				.wlen = wdata_len, .rlen = rdata_len};
719 
720 	if (!first_ec)
721 		return -ENODEV;
722 
723 	return acpi_ec_transaction(first_ec, &t);
724 }
725 EXPORT_SYMBOL(ec_transaction);
726 
727 /* Get the handle to the EC device */
728 acpi_handle ec_get_handle(void)
729 {
730 	if (!first_ec)
731 		return NULL;
732 	return first_ec->handle;
733 }
734 EXPORT_SYMBOL(ec_get_handle);
735 
736 /*
737  * Process _Q events that might have accumulated in the EC.
738  * Run with locked ec mutex.
739  */
740 static void acpi_ec_clear(struct acpi_ec *ec)
741 {
742 	int i, status;
743 	u8 value = 0;
744 
745 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
746 		status = acpi_ec_query(ec, &value);
747 		if (status || !value)
748 			break;
749 	}
750 
751 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
752 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
753 	else
754 		pr_info("%d stale EC events cleared\n", i);
755 }
756 
757 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
758 {
759 	unsigned long flags;
760 
761 	spin_lock_irqsave(&ec->lock, flags);
762 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
763 		pr_debug("+++++ Starting EC +++++\n");
764 		/* Enable GPE for event processing (SCI_EVT=1) */
765 		if (!resuming) {
766 			acpi_ec_submit_request(ec);
767 			ec_debug_ref(ec, "Increase driver\n");
768 		}
769 		pr_info("+++++ EC started +++++\n");
770 	}
771 	spin_unlock_irqrestore(&ec->lock, flags);
772 }
773 
774 static bool acpi_ec_stopped(struct acpi_ec *ec)
775 {
776 	unsigned long flags;
777 	bool flushed;
778 
779 	spin_lock_irqsave(&ec->lock, flags);
780 	flushed = acpi_ec_flushed(ec);
781 	spin_unlock_irqrestore(&ec->lock, flags);
782 	return flushed;
783 }
784 
785 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
786 {
787 	unsigned long flags;
788 
789 	spin_lock_irqsave(&ec->lock, flags);
790 	if (acpi_ec_started(ec)) {
791 		pr_debug("+++++ Stopping EC +++++\n");
792 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
793 		spin_unlock_irqrestore(&ec->lock, flags);
794 		wait_event(ec->wait, acpi_ec_stopped(ec));
795 		spin_lock_irqsave(&ec->lock, flags);
796 		/* Disable GPE for event processing (SCI_EVT=1) */
797 		if (!suspending) {
798 			acpi_ec_complete_request(ec);
799 			ec_debug_ref(ec, "Decrease driver\n");
800 		}
801 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
802 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
803 		pr_info("+++++ EC stopped +++++\n");
804 	}
805 	spin_unlock_irqrestore(&ec->lock, flags);
806 }
807 
808 void acpi_ec_block_transactions(void)
809 {
810 	struct acpi_ec *ec = first_ec;
811 
812 	if (!ec)
813 		return;
814 
815 	mutex_lock(&ec->mutex);
816 	/* Prevent transactions from being carried out */
817 	acpi_ec_stop(ec, true);
818 	mutex_unlock(&ec->mutex);
819 }
820 
821 void acpi_ec_unblock_transactions(void)
822 {
823 	struct acpi_ec *ec = first_ec;
824 
825 	if (!ec)
826 		return;
827 
828 	/* Allow transactions to be carried out again */
829 	acpi_ec_start(ec, true);
830 
831 	if (EC_FLAGS_CLEAR_ON_RESUME)
832 		acpi_ec_clear(ec);
833 }
834 
835 void acpi_ec_unblock_transactions_early(void)
836 {
837 	/*
838 	 * Allow transactions to happen again (this function is called from
839 	 * atomic context during wakeup, so we don't need to acquire the mutex).
840 	 */
841 	if (first_ec)
842 		acpi_ec_start(first_ec, true);
843 }
844 
845 /* --------------------------------------------------------------------------
846                                 Event Management
847    -------------------------------------------------------------------------- */
848 static struct acpi_ec_query_handler *
849 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
850 {
851 	if (handler)
852 		kref_get(&handler->kref);
853 	return handler;
854 }
855 
856 static void acpi_ec_query_handler_release(struct kref *kref)
857 {
858 	struct acpi_ec_query_handler *handler =
859 		container_of(kref, struct acpi_ec_query_handler, kref);
860 
861 	kfree(handler);
862 }
863 
864 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
865 {
866 	kref_put(&handler->kref, acpi_ec_query_handler_release);
867 }
868 
869 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
870 			      acpi_handle handle, acpi_ec_query_func func,
871 			      void *data)
872 {
873 	struct acpi_ec_query_handler *handler =
874 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
875 
876 	if (!handler)
877 		return -ENOMEM;
878 
879 	handler->query_bit = query_bit;
880 	handler->handle = handle;
881 	handler->func = func;
882 	handler->data = data;
883 	mutex_lock(&ec->mutex);
884 	kref_init(&handler->kref);
885 	list_add(&handler->node, &ec->list);
886 	mutex_unlock(&ec->mutex);
887 	return 0;
888 }
889 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
890 
891 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
892 {
893 	struct acpi_ec_query_handler *handler, *tmp;
894 	LIST_HEAD(free_list);
895 
896 	mutex_lock(&ec->mutex);
897 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
898 		if (query_bit == handler->query_bit) {
899 			list_del_init(&handler->node);
900 			list_add(&handler->node, &free_list);
901 		}
902 	}
903 	mutex_unlock(&ec->mutex);
904 	list_for_each_entry(handler, &free_list, node)
905 		acpi_ec_put_query_handler(handler);
906 }
907 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
908 
909 static void acpi_ec_run(void *cxt)
910 {
911 	struct acpi_ec_query_handler *handler = cxt;
912 
913 	if (!handler)
914 		return;
915 	pr_debug("##### Query(0x%02x) started #####\n", handler->query_bit);
916 	if (handler->func)
917 		handler->func(handler->data);
918 	else if (handler->handle)
919 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
920 	pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
921 	acpi_ec_put_query_handler(handler);
922 }
923 
924 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
925 {
926 	u8 value = 0;
927 	int result;
928 	acpi_status status;
929 	struct acpi_ec_query_handler *handler;
930 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
931 				.wdata = NULL, .rdata = &value,
932 				.wlen = 0, .rlen = 1};
933 
934 	/*
935 	 * Query the EC to find out which _Qxx method we need to evaluate.
936 	 * Note that successful completion of the query causes the ACPI_EC_SCI
937 	 * bit to be cleared (and thus clearing the interrupt source).
938 	 */
939 	result = acpi_ec_transaction(ec, &t);
940 	if (result)
941 		return result;
942 	if (data)
943 		*data = value;
944 	if (!value)
945 		return -ENODATA;
946 
947 	mutex_lock(&ec->mutex);
948 	list_for_each_entry(handler, &ec->list, node) {
949 		if (value == handler->query_bit) {
950 			/* have custom handler for this bit */
951 			handler = acpi_ec_get_query_handler(handler);
952 			pr_debug("##### Query(0x%02x) scheduled #####\n",
953 				 handler->query_bit);
954 			status = acpi_os_execute((handler->func) ?
955 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
956 				acpi_ec_run, handler);
957 			if (ACPI_FAILURE(status))
958 				result = -EBUSY;
959 			break;
960 		}
961 	}
962 	mutex_unlock(&ec->mutex);
963 	return result;
964 }
965 
966 static void acpi_ec_gpe_poller(struct work_struct *work)
967 {
968 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
969 
970 	pr_debug("***** Event poller started *****\n");
971 	acpi_ec_query(ec, NULL);
972 	pr_debug("***** Event poller stopped *****\n");
973 }
974 
975 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
976 	u32 gpe_number, void *data)
977 {
978 	unsigned long flags;
979 	struct acpi_ec *ec = data;
980 
981 	spin_lock_irqsave(&ec->lock, flags);
982 	advance_transaction(ec);
983 	spin_unlock_irqrestore(&ec->lock, flags);
984 	return ACPI_INTERRUPT_HANDLED;
985 }
986 
987 /* --------------------------------------------------------------------------
988  *                           Address Space Management
989  * -------------------------------------------------------------------------- */
990 
991 static acpi_status
992 acpi_ec_space_handler(u32 function, acpi_physical_address address,
993 		      u32 bits, u64 *value64,
994 		      void *handler_context, void *region_context)
995 {
996 	struct acpi_ec *ec = handler_context;
997 	int result = 0, i, bytes = bits / 8;
998 	u8 *value = (u8 *)value64;
999 
1000 	if ((address > 0xFF) || !value || !handler_context)
1001 		return AE_BAD_PARAMETER;
1002 
1003 	if (function != ACPI_READ && function != ACPI_WRITE)
1004 		return AE_BAD_PARAMETER;
1005 
1006 	if (EC_FLAGS_MSI || bits > 8)
1007 		acpi_ec_burst_enable(ec);
1008 
1009 	for (i = 0; i < bytes; ++i, ++address, ++value)
1010 		result = (function == ACPI_READ) ?
1011 			acpi_ec_read(ec, address, value) :
1012 			acpi_ec_write(ec, address, *value);
1013 
1014 	if (EC_FLAGS_MSI || bits > 8)
1015 		acpi_ec_burst_disable(ec);
1016 
1017 	switch (result) {
1018 	case -EINVAL:
1019 		return AE_BAD_PARAMETER;
1020 	case -ENODEV:
1021 		return AE_NOT_FOUND;
1022 	case -ETIME:
1023 		return AE_TIME;
1024 	default:
1025 		return AE_OK;
1026 	}
1027 }
1028 
1029 /* --------------------------------------------------------------------------
1030  *                             Driver Interface
1031  * -------------------------------------------------------------------------- */
1032 
1033 static acpi_status
1034 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1035 
1036 static struct acpi_ec *make_acpi_ec(void)
1037 {
1038 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1039 
1040 	if (!ec)
1041 		return NULL;
1042 	mutex_init(&ec->mutex);
1043 	init_waitqueue_head(&ec->wait);
1044 	INIT_LIST_HEAD(&ec->list);
1045 	spin_lock_init(&ec->lock);
1046 	INIT_WORK(&ec->work, acpi_ec_gpe_poller);
1047 	return ec;
1048 }
1049 
1050 static acpi_status
1051 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1052 			       void *context, void **return_value)
1053 {
1054 	char node_name[5];
1055 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1056 	struct acpi_ec *ec = context;
1057 	int value = 0;
1058 	acpi_status status;
1059 
1060 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1061 
1062 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1063 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1064 	return AE_OK;
1065 }
1066 
1067 static acpi_status
1068 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1069 {
1070 	acpi_status status;
1071 	unsigned long long tmp = 0;
1072 	struct acpi_ec *ec = context;
1073 
1074 	/* clear addr values, ec_parse_io_ports depend on it */
1075 	ec->command_addr = ec->data_addr = 0;
1076 
1077 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1078 				     ec_parse_io_ports, ec);
1079 	if (ACPI_FAILURE(status))
1080 		return status;
1081 
1082 	/* Get GPE bit assignment (EC events). */
1083 	/* TODO: Add support for _GPE returning a package */
1084 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1085 	if (ACPI_FAILURE(status))
1086 		return status;
1087 	ec->gpe = tmp;
1088 	/* Use the global lock for all EC transactions? */
1089 	tmp = 0;
1090 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1091 	ec->global_lock = tmp;
1092 	ec->handle = handle;
1093 	return AE_CTRL_TERMINATE;
1094 }
1095 
1096 static int ec_install_handlers(struct acpi_ec *ec)
1097 {
1098 	acpi_status status;
1099 
1100 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1101 		return 0;
1102 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1103 				  ACPI_GPE_EDGE_TRIGGERED,
1104 				  &acpi_ec_gpe_handler, ec);
1105 	if (ACPI_FAILURE(status))
1106 		return -ENODEV;
1107 
1108 	acpi_ec_start(ec, false);
1109 	status = acpi_install_address_space_handler(ec->handle,
1110 						    ACPI_ADR_SPACE_EC,
1111 						    &acpi_ec_space_handler,
1112 						    NULL, ec);
1113 	if (ACPI_FAILURE(status)) {
1114 		if (status == AE_NOT_FOUND) {
1115 			/*
1116 			 * Maybe OS fails in evaluating the _REG object.
1117 			 * The AE_NOT_FOUND error will be ignored and OS
1118 			 * continue to initialize EC.
1119 			 */
1120 			pr_err("Fail in evaluating the _REG object"
1121 				" of EC device. Broken bios is suspected.\n");
1122 		} else {
1123 			acpi_ec_stop(ec, false);
1124 			acpi_remove_gpe_handler(NULL, ec->gpe,
1125 				&acpi_ec_gpe_handler);
1126 			return -ENODEV;
1127 		}
1128 	}
1129 
1130 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1131 	return 0;
1132 }
1133 
1134 static void ec_remove_handlers(struct acpi_ec *ec)
1135 {
1136 	if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
1137 		return;
1138 	acpi_ec_stop(ec, false);
1139 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1140 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1141 		pr_err("failed to remove space handler\n");
1142 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1143 				&acpi_ec_gpe_handler)))
1144 		pr_err("failed to remove gpe handler\n");
1145 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
1146 }
1147 
1148 static int acpi_ec_add(struct acpi_device *device)
1149 {
1150 	struct acpi_ec *ec = NULL;
1151 	int ret;
1152 
1153 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1154 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1155 
1156 	/* Check for boot EC */
1157 	if (boot_ec &&
1158 	    (boot_ec->handle == device->handle ||
1159 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
1160 		ec = boot_ec;
1161 		boot_ec = NULL;
1162 	} else {
1163 		ec = make_acpi_ec();
1164 		if (!ec)
1165 			return -ENOMEM;
1166 	}
1167 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
1168 		AE_CTRL_TERMINATE) {
1169 			kfree(ec);
1170 			return -EINVAL;
1171 	}
1172 
1173 	/* Find and register all query methods */
1174 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1175 			    acpi_ec_register_query_methods, NULL, ec, NULL);
1176 
1177 	if (!first_ec)
1178 		first_ec = ec;
1179 	device->driver_data = ec;
1180 
1181 	ret = !!request_region(ec->data_addr, 1, "EC data");
1182 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1183 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1184 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1185 
1186 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
1187 			  ec->gpe, ec->command_addr, ec->data_addr);
1188 
1189 	ret = ec_install_handlers(ec);
1190 
1191 	/* EC is fully operational, allow queries */
1192 	acpi_ec_enable_event(ec);
1193 
1194 	/* Clear stale _Q events if hardware might require that */
1195 	if (EC_FLAGS_CLEAR_ON_RESUME)
1196 		acpi_ec_clear(ec);
1197 	return ret;
1198 }
1199 
1200 static int acpi_ec_remove(struct acpi_device *device)
1201 {
1202 	struct acpi_ec *ec;
1203 	struct acpi_ec_query_handler *handler, *tmp;
1204 
1205 	if (!device)
1206 		return -EINVAL;
1207 
1208 	ec = acpi_driver_data(device);
1209 	ec_remove_handlers(ec);
1210 	mutex_lock(&ec->mutex);
1211 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1212 		list_del(&handler->node);
1213 		kfree(handler);
1214 	}
1215 	mutex_unlock(&ec->mutex);
1216 	release_region(ec->data_addr, 1);
1217 	release_region(ec->command_addr, 1);
1218 	device->driver_data = NULL;
1219 	if (ec == first_ec)
1220 		first_ec = NULL;
1221 	kfree(ec);
1222 	return 0;
1223 }
1224 
1225 static acpi_status
1226 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1227 {
1228 	struct acpi_ec *ec = context;
1229 
1230 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1231 		return AE_OK;
1232 
1233 	/*
1234 	 * The first address region returned is the data port, and
1235 	 * the second address region returned is the status/command
1236 	 * port.
1237 	 */
1238 	if (ec->data_addr == 0)
1239 		ec->data_addr = resource->data.io.minimum;
1240 	else if (ec->command_addr == 0)
1241 		ec->command_addr = resource->data.io.minimum;
1242 	else
1243 		return AE_CTRL_TERMINATE;
1244 
1245 	return AE_OK;
1246 }
1247 
1248 int __init acpi_boot_ec_enable(void)
1249 {
1250 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
1251 		return 0;
1252 	if (!ec_install_handlers(boot_ec)) {
1253 		first_ec = boot_ec;
1254 		return 0;
1255 	}
1256 	return -EFAULT;
1257 }
1258 
1259 static const struct acpi_device_id ec_device_ids[] = {
1260 	{"PNP0C09", 0},
1261 	{"", 0},
1262 };
1263 
1264 /* Some BIOS do not survive early DSDT scan, skip it */
1265 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
1266 {
1267 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
1268 	return 0;
1269 }
1270 
1271 /* ASUStek often supplies us with broken ECDT, validate it */
1272 static int ec_validate_ecdt(const struct dmi_system_id *id)
1273 {
1274 	EC_FLAGS_VALIDATE_ECDT = 1;
1275 	return 0;
1276 }
1277 
1278 /* MSI EC needs special treatment, enable it */
1279 static int ec_flag_msi(const struct dmi_system_id *id)
1280 {
1281 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
1282 	EC_FLAGS_MSI = 1;
1283 	EC_FLAGS_VALIDATE_ECDT = 1;
1284 	return 0;
1285 }
1286 
1287 /*
1288  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
1289  * the GPE storm threshold back to 20
1290  */
1291 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
1292 {
1293 	pr_debug("Setting the EC GPE storm threshold to 20\n");
1294 	ec_storm_threshold  = 20;
1295 	return 0;
1296 }
1297 
1298 /*
1299  * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
1300  * which case, we complete the QR_EC without issuing it to the firmware.
1301  * https://bugzilla.kernel.org/show_bug.cgi?id=86211
1302  */
1303 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1304 {
1305 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1306 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1307 	return 0;
1308 }
1309 
1310 /*
1311  * On some hardware it is necessary to clear events accumulated by the EC during
1312  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1313  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1314  *
1315  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1316  *
1317  * Ideally, the EC should also be instructed NOT to accumulate events during
1318  * sleep (which Windows seems to do somehow), but the interface to control this
1319  * behaviour is not known at this time.
1320  *
1321  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1322  * however it is very likely that other Samsung models are affected.
1323  *
1324  * On systems which don't accumulate _Q events during sleep, this extra check
1325  * should be harmless.
1326  */
1327 static int ec_clear_on_resume(const struct dmi_system_id *id)
1328 {
1329 	pr_debug("Detected system needing EC poll on resume.\n");
1330 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1331 	return 0;
1332 }
1333 
1334 static struct dmi_system_id ec_dmi_table[] __initdata = {
1335 	{
1336 	ec_skip_dsdt_scan, "Compal JFL92", {
1337 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1338 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1339 	{
1340 	ec_flag_msi, "MSI hardware", {
1341 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1342 	{
1343 	ec_flag_msi, "MSI hardware", {
1344 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
1345 	{
1346 	ec_flag_msi, "MSI hardware", {
1347 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1348 	{
1349 	ec_flag_msi, "MSI hardware", {
1350 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1351 	{
1352 	ec_flag_msi, "Quanta hardware", {
1353 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1354 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1355 	{
1356 	ec_flag_msi, "Quanta hardware", {
1357 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1358 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1359 	{
1360 	ec_flag_msi, "Clevo W350etq", {
1361 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
1362 	DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
1363 	{
1364 	ec_validate_ecdt, "ASUS hardware", {
1365 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1366 	{
1367 	ec_validate_ecdt, "ASUS hardware", {
1368 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1369 	{
1370 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1371 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1372 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1373 	{
1374 	ec_skip_dsdt_scan, "HP Folio 13", {
1375 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1376 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1377 	{
1378 	ec_validate_ecdt, "ASUS hardware", {
1379 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1380 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1381 	{
1382 	ec_clear_on_resume, "Samsung hardware", {
1383 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1384 	{
1385 	ec_flag_query_handshake, "Acer hardware", {
1386 	DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
1387 	{},
1388 };
1389 
1390 int __init acpi_ec_ecdt_probe(void)
1391 {
1392 	acpi_status status;
1393 	struct acpi_ec *saved_ec = NULL;
1394 	struct acpi_table_ecdt *ecdt_ptr;
1395 
1396 	boot_ec = make_acpi_ec();
1397 	if (!boot_ec)
1398 		return -ENOMEM;
1399 	/*
1400 	 * Generate a boot ec context
1401 	 */
1402 	dmi_check_system(ec_dmi_table);
1403 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1404 				(struct acpi_table_header **)&ecdt_ptr);
1405 	if (ACPI_SUCCESS(status)) {
1406 		pr_info("EC description table is found, configuring boot EC\n");
1407 		boot_ec->command_addr = ecdt_ptr->control.address;
1408 		boot_ec->data_addr = ecdt_ptr->data.address;
1409 		boot_ec->gpe = ecdt_ptr->gpe;
1410 		boot_ec->handle = ACPI_ROOT_OBJECT;
1411 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1412 				&boot_ec->handle);
1413 		/* Don't trust ECDT, which comes from ASUSTek */
1414 		if (!EC_FLAGS_VALIDATE_ECDT)
1415 			goto install;
1416 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1417 		if (!saved_ec)
1418 			return -ENOMEM;
1419 	/* fall through */
1420 	}
1421 
1422 	if (EC_FLAGS_SKIP_DSDT_SCAN) {
1423 		kfree(saved_ec);
1424 		return -ENODEV;
1425 	}
1426 
1427 	/* This workaround is needed only on some broken machines,
1428 	 * which require early EC, but fail to provide ECDT */
1429 	pr_debug("Look up EC in DSDT\n");
1430 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1431 					boot_ec, NULL);
1432 	/* Check that acpi_get_devices actually find something */
1433 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1434 		goto error;
1435 	if (saved_ec) {
1436 		/* try to find good ECDT from ASUSTek */
1437 		if (saved_ec->command_addr != boot_ec->command_addr ||
1438 		    saved_ec->data_addr != boot_ec->data_addr ||
1439 		    saved_ec->gpe != boot_ec->gpe ||
1440 		    saved_ec->handle != boot_ec->handle)
1441 			pr_info("ASUSTek keeps feeding us with broken "
1442 			"ECDT tables, which are very hard to workaround. "
1443 			"Trying to use DSDT EC info instead. Please send "
1444 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1445 		kfree(saved_ec);
1446 		saved_ec = NULL;
1447 	} else {
1448 		/* We really need to limit this workaround, the only ASUS,
1449 		* which needs it, has fake EC._INI method, so use it as flag.
1450 		* Keep boot_ec struct as it will be needed soon.
1451 		*/
1452 		if (!dmi_name_in_vendors("ASUS") ||
1453 		    !acpi_has_method(boot_ec->handle, "_INI"))
1454 			return -ENODEV;
1455 	}
1456 install:
1457 	if (!ec_install_handlers(boot_ec)) {
1458 		first_ec = boot_ec;
1459 		return 0;
1460 	}
1461 error:
1462 	kfree(boot_ec);
1463 	kfree(saved_ec);
1464 	boot_ec = NULL;
1465 	return -ENODEV;
1466 }
1467 
1468 static struct acpi_driver acpi_ec_driver = {
1469 	.name = "ec",
1470 	.class = ACPI_EC_CLASS,
1471 	.ids = ec_device_ids,
1472 	.ops = {
1473 		.add = acpi_ec_add,
1474 		.remove = acpi_ec_remove,
1475 		},
1476 };
1477 
1478 int __init acpi_ec_init(void)
1479 {
1480 	int result = 0;
1481 
1482 	/* Now register the driver for the EC */
1483 	result = acpi_bus_register_driver(&acpi_ec_driver);
1484 	if (result < 0)
1485 		return -ENODEV;
1486 
1487 	return result;
1488 }
1489 
1490 /* EC driver currently not unloadable */
1491 #if 0
1492 static void __exit acpi_ec_exit(void)
1493 {
1494 
1495 	acpi_bus_unregister_driver(&acpi_ec_driver);
1496 }
1497 #endif	/* 0 */
1498