xref: /openbmc/linux/drivers/acpi/ec.c (revision 867a0e05)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v2.2)
3  *
4  *  Copyright (C) 2001-2014 Intel Corporation
5  *    Author: 2014       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_CLEAR_MAX	100	/* Maximum number of events to query
75 					 * when trying to clear the EC */
76 
77 enum {
78 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
79 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
80 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
81 					 * OpReg are installed */
82 	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
83 };
84 
85 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
86 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
87 
88 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
89 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
90 module_param(ec_delay, uint, 0644);
91 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
92 
93 /*
94  * If the number of false interrupts per one transaction exceeds
95  * this threshold, will think there is a GPE storm happened and
96  * will disable the GPE for normal transaction.
97  */
98 static unsigned int ec_storm_threshold  __read_mostly = 8;
99 module_param(ec_storm_threshold, uint, 0644);
100 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
101 
102 struct acpi_ec_query_handler {
103 	struct list_head node;
104 	acpi_ec_query_func func;
105 	acpi_handle handle;
106 	void *data;
107 	u8 query_bit;
108 };
109 
110 struct transaction {
111 	const u8 *wdata;
112 	u8 *rdata;
113 	unsigned short irq_count;
114 	u8 command;
115 	u8 wi;
116 	u8 ri;
117 	u8 wlen;
118 	u8 rlen;
119 	u8 flags;
120 };
121 
122 struct acpi_ec *boot_ec, *first_ec;
123 EXPORT_SYMBOL(first_ec);
124 
125 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
126 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
127 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
128 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
129 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
130 
131 /* --------------------------------------------------------------------------
132  *                           Transaction Management
133  * -------------------------------------------------------------------------- */
134 
135 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
136 {
137 	u8 x = inb(ec->command_addr);
138 
139 	pr_debug("EC_SC(R) = 0x%2.2x "
140 		 "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
141 		 x,
142 		 !!(x & ACPI_EC_FLAG_SCI),
143 		 !!(x & ACPI_EC_FLAG_BURST),
144 		 !!(x & ACPI_EC_FLAG_CMD),
145 		 !!(x & ACPI_EC_FLAG_IBF),
146 		 !!(x & ACPI_EC_FLAG_OBF));
147 	return x;
148 }
149 
150 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
151 {
152 	u8 x = inb(ec->data_addr);
153 
154 	pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
155 	return x;
156 }
157 
158 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
159 {
160 	pr_debug("EC_SC(W) = 0x%2.2x\n", command);
161 	outb(command, ec->command_addr);
162 }
163 
164 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
165 {
166 	pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
167 	outb(data, ec->data_addr);
168 }
169 
170 #ifdef DEBUG
171 static const char *acpi_ec_cmd_string(u8 cmd)
172 {
173 	switch (cmd) {
174 	case 0x80:
175 		return "RD_EC";
176 	case 0x81:
177 		return "WR_EC";
178 	case 0x82:
179 		return "BE_EC";
180 	case 0x83:
181 		return "BD_EC";
182 	case 0x84:
183 		return "QR_EC";
184 	}
185 	return "UNKNOWN";
186 }
187 #else
188 #define acpi_ec_cmd_string(cmd)		"UNDEF"
189 #endif
190 
191 static int ec_transaction_completed(struct acpi_ec *ec)
192 {
193 	unsigned long flags;
194 	int ret = 0;
195 
196 	spin_lock_irqsave(&ec->lock, flags);
197 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
198 		ret = 1;
199 	spin_unlock_irqrestore(&ec->lock, flags);
200 	return ret;
201 }
202 
203 static bool advance_transaction(struct acpi_ec *ec)
204 {
205 	struct transaction *t;
206 	u8 status;
207 	bool wakeup = false;
208 
209 	pr_debug("===== %s (%d) =====\n",
210 		 in_interrupt() ? "IRQ" : "TASK", smp_processor_id());
211 	status = acpi_ec_read_status(ec);
212 	t = ec->curr;
213 	if (!t)
214 		goto err;
215 	if (t->flags & ACPI_EC_COMMAND_POLL) {
216 		if (t->wlen > t->wi) {
217 			if ((status & ACPI_EC_FLAG_IBF) == 0)
218 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
219 			else
220 				goto err;
221 		} else if (t->rlen > t->ri) {
222 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
223 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
224 				if (t->rlen == t->ri) {
225 					t->flags |= ACPI_EC_COMMAND_COMPLETE;
226 					if (t->command == ACPI_EC_COMMAND_QUERY)
227 						pr_debug("***** Command(%s) hardware completion *****\n",
228 							 acpi_ec_cmd_string(t->command));
229 					wakeup = true;
230 				}
231 			} else
232 				goto err;
233 		} else if (t->wlen == t->wi &&
234 			   (status & ACPI_EC_FLAG_IBF) == 0) {
235 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
236 			wakeup = true;
237 		}
238 		return wakeup;
239 	} else {
240 		if (EC_FLAGS_QUERY_HANDSHAKE &&
241 		    !(status & ACPI_EC_FLAG_SCI) &&
242 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
243 			t->flags |= ACPI_EC_COMMAND_POLL;
244 			t->rdata[t->ri++] = 0x00;
245 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
246 			pr_debug("***** Command(%s) software completion *****\n",
247 				 acpi_ec_cmd_string(t->command));
248 			wakeup = true;
249 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
250 			acpi_ec_write_cmd(ec, t->command);
251 			t->flags |= ACPI_EC_COMMAND_POLL;
252 		} else
253 			goto err;
254 		return wakeup;
255 	}
256 err:
257 	/*
258 	 * If SCI bit is set, then don't think it's a false IRQ
259 	 * otherwise will take a not handled IRQ as a false one.
260 	 */
261 	if (!(status & ACPI_EC_FLAG_SCI)) {
262 		if (in_interrupt() && t)
263 			++t->irq_count;
264 	}
265 	return wakeup;
266 }
267 
268 static void start_transaction(struct acpi_ec *ec)
269 {
270 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
271 	ec->curr->flags = 0;
272 	(void)advance_transaction(ec);
273 }
274 
275 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data);
276 
277 static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
278 {
279 	if (state & ACPI_EC_FLAG_SCI) {
280 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
281 			return acpi_ec_sync_query(ec, NULL);
282 	}
283 	return 0;
284 }
285 
286 static int ec_poll(struct acpi_ec *ec)
287 {
288 	unsigned long flags;
289 	int repeat = 5; /* number of command restarts */
290 
291 	while (repeat--) {
292 		unsigned long delay = jiffies +
293 			msecs_to_jiffies(ec_delay);
294 		do {
295 			/* don't sleep with disabled interrupts */
296 			if (EC_FLAGS_MSI || irqs_disabled()) {
297 				udelay(ACPI_EC_MSI_UDELAY);
298 				if (ec_transaction_completed(ec))
299 					return 0;
300 			} else {
301 				if (wait_event_timeout(ec->wait,
302 						ec_transaction_completed(ec),
303 						msecs_to_jiffies(1)))
304 					return 0;
305 			}
306 			spin_lock_irqsave(&ec->lock, flags);
307 			(void)advance_transaction(ec);
308 			spin_unlock_irqrestore(&ec->lock, flags);
309 		} while (time_before(jiffies, delay));
310 		pr_debug("controller reset, restart transaction\n");
311 		spin_lock_irqsave(&ec->lock, flags);
312 		start_transaction(ec);
313 		spin_unlock_irqrestore(&ec->lock, flags);
314 	}
315 	return -ETIME;
316 }
317 
318 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
319 					struct transaction *t)
320 {
321 	unsigned long tmp;
322 	int ret = 0;
323 
324 	if (EC_FLAGS_MSI)
325 		udelay(ACPI_EC_MSI_UDELAY);
326 	/* start transaction */
327 	spin_lock_irqsave(&ec->lock, tmp);
328 	/* following two actions should be kept atomic */
329 	ec->curr = t;
330 	pr_debug("***** Command(%s) started *****\n",
331 		 acpi_ec_cmd_string(t->command));
332 	start_transaction(ec);
333 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
334 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
335 		pr_debug("***** Event stopped *****\n");
336 	}
337 	spin_unlock_irqrestore(&ec->lock, tmp);
338 	ret = ec_poll(ec);
339 	spin_lock_irqsave(&ec->lock, tmp);
340 	pr_debug("***** Command(%s) stopped *****\n",
341 		 acpi_ec_cmd_string(t->command));
342 	ec->curr = NULL;
343 	spin_unlock_irqrestore(&ec->lock, tmp);
344 	return ret;
345 }
346 
347 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
348 {
349 	int status;
350 	u32 glk;
351 
352 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
353 		return -EINVAL;
354 	if (t->rdata)
355 		memset(t->rdata, 0, t->rlen);
356 	mutex_lock(&ec->mutex);
357 	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
358 		status = -EINVAL;
359 		goto unlock;
360 	}
361 	if (ec->global_lock) {
362 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
363 		if (ACPI_FAILURE(status)) {
364 			status = -ENODEV;
365 			goto unlock;
366 		}
367 	}
368 	/* disable GPE during transaction if storm is detected */
369 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
370 		/* It has to be disabled, so that it doesn't trigger. */
371 		acpi_disable_gpe(NULL, ec->gpe);
372 	}
373 
374 	status = acpi_ec_transaction_unlocked(ec, t);
375 
376 	/* check if we received SCI during transaction */
377 	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
378 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
379 		msleep(1);
380 		/* It is safe to enable the GPE outside of the transaction. */
381 		acpi_enable_gpe(NULL, ec->gpe);
382 	} else if (t->irq_count > ec_storm_threshold) {
383 		pr_info("GPE storm detected(%d GPEs), "
384 			"transactions will use polling mode\n",
385 			t->irq_count);
386 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
387 	}
388 	if (ec->global_lock)
389 		acpi_release_global_lock(glk);
390 unlock:
391 	mutex_unlock(&ec->mutex);
392 	return status;
393 }
394 
395 static int acpi_ec_burst_enable(struct acpi_ec *ec)
396 {
397 	u8 d;
398 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
399 				.wdata = NULL, .rdata = &d,
400 				.wlen = 0, .rlen = 1};
401 
402 	return acpi_ec_transaction(ec, &t);
403 }
404 
405 static int acpi_ec_burst_disable(struct acpi_ec *ec)
406 {
407 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
408 				.wdata = NULL, .rdata = NULL,
409 				.wlen = 0, .rlen = 0};
410 
411 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
412 				acpi_ec_transaction(ec, &t) : 0;
413 }
414 
415 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
416 {
417 	int result;
418 	u8 d;
419 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
420 				.wdata = &address, .rdata = &d,
421 				.wlen = 1, .rlen = 1};
422 
423 	result = acpi_ec_transaction(ec, &t);
424 	*data = d;
425 	return result;
426 }
427 
428 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
429 {
430 	u8 wdata[2] = { address, data };
431 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
432 				.wdata = wdata, .rdata = NULL,
433 				.wlen = 2, .rlen = 0};
434 
435 	return acpi_ec_transaction(ec, &t);
436 }
437 
438 int ec_read(u8 addr, u8 *val)
439 {
440 	int err;
441 	u8 temp_data;
442 
443 	if (!first_ec)
444 		return -ENODEV;
445 
446 	err = acpi_ec_read(first_ec, addr, &temp_data);
447 
448 	if (!err) {
449 		*val = temp_data;
450 		return 0;
451 	}
452 	return err;
453 }
454 EXPORT_SYMBOL(ec_read);
455 
456 int ec_write(u8 addr, u8 val)
457 {
458 	int err;
459 
460 	if (!first_ec)
461 		return -ENODEV;
462 
463 	err = acpi_ec_write(first_ec, addr, val);
464 
465 	return err;
466 }
467 EXPORT_SYMBOL(ec_write);
468 
469 int ec_transaction(u8 command,
470 		   const u8 *wdata, unsigned wdata_len,
471 		   u8 *rdata, unsigned rdata_len)
472 {
473 	struct transaction t = {.command = command,
474 				.wdata = wdata, .rdata = rdata,
475 				.wlen = wdata_len, .rlen = rdata_len};
476 
477 	if (!first_ec)
478 		return -ENODEV;
479 
480 	return acpi_ec_transaction(first_ec, &t);
481 }
482 EXPORT_SYMBOL(ec_transaction);
483 
484 /* Get the handle to the EC device */
485 acpi_handle ec_get_handle(void)
486 {
487 	if (!first_ec)
488 		return NULL;
489 	return first_ec->handle;
490 }
491 EXPORT_SYMBOL(ec_get_handle);
492 
493 /*
494  * Process _Q events that might have accumulated in the EC.
495  * Run with locked ec mutex.
496  */
497 static void acpi_ec_clear(struct acpi_ec *ec)
498 {
499 	int i, status;
500 	u8 value = 0;
501 
502 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
503 		status = acpi_ec_sync_query(ec, &value);
504 		if (status || !value)
505 			break;
506 	}
507 
508 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
509 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
510 	else
511 		pr_info("%d stale EC events cleared\n", i);
512 }
513 
514 void acpi_ec_block_transactions(void)
515 {
516 	struct acpi_ec *ec = first_ec;
517 
518 	if (!ec)
519 		return;
520 
521 	mutex_lock(&ec->mutex);
522 	/* Prevent transactions from being carried out */
523 	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
524 	mutex_unlock(&ec->mutex);
525 }
526 
527 void acpi_ec_unblock_transactions(void)
528 {
529 	struct acpi_ec *ec = first_ec;
530 
531 	if (!ec)
532 		return;
533 
534 	mutex_lock(&ec->mutex);
535 	/* Allow transactions to be carried out again */
536 	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
537 
538 	if (EC_FLAGS_CLEAR_ON_RESUME)
539 		acpi_ec_clear(ec);
540 
541 	mutex_unlock(&ec->mutex);
542 }
543 
544 void acpi_ec_unblock_transactions_early(void)
545 {
546 	/*
547 	 * Allow transactions to happen again (this function is called from
548 	 * atomic context during wakeup, so we don't need to acquire the mutex).
549 	 */
550 	if (first_ec)
551 		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
552 }
553 
554 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data)
555 {
556 	int result;
557 	u8 d;
558 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
559 				.wdata = NULL, .rdata = &d,
560 				.wlen = 0, .rlen = 1};
561 
562 	if (!ec || !data)
563 		return -EINVAL;
564 	/*
565 	 * Query the EC to find out which _Qxx method we need to evaluate.
566 	 * Note that successful completion of the query causes the ACPI_EC_SCI
567 	 * bit to be cleared (and thus clearing the interrupt source).
568 	 */
569 	result = acpi_ec_transaction_unlocked(ec, &t);
570 	if (result)
571 		return result;
572 	if (!d)
573 		return -ENODATA;
574 	*data = d;
575 	return 0;
576 }
577 
578 /* --------------------------------------------------------------------------
579                                 Event Management
580    -------------------------------------------------------------------------- */
581 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
582 			      acpi_handle handle, acpi_ec_query_func func,
583 			      void *data)
584 {
585 	struct acpi_ec_query_handler *handler =
586 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
587 
588 	if (!handler)
589 		return -ENOMEM;
590 
591 	handler->query_bit = query_bit;
592 	handler->handle = handle;
593 	handler->func = func;
594 	handler->data = data;
595 	mutex_lock(&ec->mutex);
596 	list_add(&handler->node, &ec->list);
597 	mutex_unlock(&ec->mutex);
598 	return 0;
599 }
600 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
601 
602 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
603 {
604 	struct acpi_ec_query_handler *handler, *tmp;
605 
606 	mutex_lock(&ec->mutex);
607 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
608 		if (query_bit == handler->query_bit) {
609 			list_del(&handler->node);
610 			kfree(handler);
611 		}
612 	}
613 	mutex_unlock(&ec->mutex);
614 }
615 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
616 
617 static void acpi_ec_run(void *cxt)
618 {
619 	struct acpi_ec_query_handler *handler = cxt;
620 
621 	if (!handler)
622 		return;
623 	pr_debug("##### Query(0x%02x) started #####\n", handler->query_bit);
624 	if (handler->func)
625 		handler->func(handler->data);
626 	else if (handler->handle)
627 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
628 	pr_debug("##### Query(0x%02x) stopped #####\n", handler->query_bit);
629 	kfree(handler);
630 }
631 
632 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
633 {
634 	u8 value = 0;
635 	int status;
636 	struct acpi_ec_query_handler *handler, *copy;
637 
638 	status = acpi_ec_query_unlocked(ec, &value);
639 	if (data)
640 		*data = value;
641 	if (status)
642 		return status;
643 
644 	list_for_each_entry(handler, &ec->list, node) {
645 		if (value == handler->query_bit) {
646 			/* have custom handler for this bit */
647 			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
648 			if (!copy)
649 				return -ENOMEM;
650 			memcpy(copy, handler, sizeof(*copy));
651 			pr_debug("##### Query(0x%02x) scheduled #####\n",
652 				 handler->query_bit);
653 			return acpi_os_execute((copy->func) ?
654 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
655 				acpi_ec_run, copy);
656 		}
657 	}
658 	return 0;
659 }
660 
661 static void acpi_ec_gpe_query(void *ec_cxt)
662 {
663 	struct acpi_ec *ec = ec_cxt;
664 
665 	if (!ec)
666 		return;
667 	mutex_lock(&ec->mutex);
668 	acpi_ec_sync_query(ec, NULL);
669 	mutex_unlock(&ec->mutex);
670 }
671 
672 static int ec_check_sci(struct acpi_ec *ec, u8 state)
673 {
674 	if (state & ACPI_EC_FLAG_SCI) {
675 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
676 			pr_debug("***** Event started *****\n");
677 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
678 				acpi_ec_gpe_query, ec);
679 		}
680 	}
681 	return 0;
682 }
683 
684 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
685 	u32 gpe_number, void *data)
686 {
687 	unsigned long flags;
688 	struct acpi_ec *ec = data;
689 
690 	spin_lock_irqsave(&ec->lock, flags);
691 	if (advance_transaction(ec))
692 		wake_up(&ec->wait);
693 	spin_unlock_irqrestore(&ec->lock, flags);
694 	ec_check_sci(ec, acpi_ec_read_status(ec));
695 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
696 }
697 
698 /* --------------------------------------------------------------------------
699  *                           Address Space Management
700  * -------------------------------------------------------------------------- */
701 
702 static acpi_status
703 acpi_ec_space_handler(u32 function, acpi_physical_address address,
704 		      u32 bits, u64 *value64,
705 		      void *handler_context, void *region_context)
706 {
707 	struct acpi_ec *ec = handler_context;
708 	int result = 0, i, bytes = bits / 8;
709 	u8 *value = (u8 *)value64;
710 
711 	if ((address > 0xFF) || !value || !handler_context)
712 		return AE_BAD_PARAMETER;
713 
714 	if (function != ACPI_READ && function != ACPI_WRITE)
715 		return AE_BAD_PARAMETER;
716 
717 	if (EC_FLAGS_MSI || bits > 8)
718 		acpi_ec_burst_enable(ec);
719 
720 	for (i = 0; i < bytes; ++i, ++address, ++value)
721 		result = (function == ACPI_READ) ?
722 			acpi_ec_read(ec, address, value) :
723 			acpi_ec_write(ec, address, *value);
724 
725 	if (EC_FLAGS_MSI || bits > 8)
726 		acpi_ec_burst_disable(ec);
727 
728 	switch (result) {
729 	case -EINVAL:
730 		return AE_BAD_PARAMETER;
731 	case -ENODEV:
732 		return AE_NOT_FOUND;
733 	case -ETIME:
734 		return AE_TIME;
735 	default:
736 		return AE_OK;
737 	}
738 }
739 
740 /* --------------------------------------------------------------------------
741  *                             Driver Interface
742  * -------------------------------------------------------------------------- */
743 
744 static acpi_status
745 ec_parse_io_ports(struct acpi_resource *resource, void *context);
746 
747 static struct acpi_ec *make_acpi_ec(void)
748 {
749 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
750 
751 	if (!ec)
752 		return NULL;
753 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
754 	mutex_init(&ec->mutex);
755 	init_waitqueue_head(&ec->wait);
756 	INIT_LIST_HEAD(&ec->list);
757 	spin_lock_init(&ec->lock);
758 	return ec;
759 }
760 
761 static acpi_status
762 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
763 			       void *context, void **return_value)
764 {
765 	char node_name[5];
766 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
767 	struct acpi_ec *ec = context;
768 	int value = 0;
769 	acpi_status status;
770 
771 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
772 
773 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
774 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
775 	return AE_OK;
776 }
777 
778 static acpi_status
779 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
780 {
781 	acpi_status status;
782 	unsigned long long tmp = 0;
783 	struct acpi_ec *ec = context;
784 
785 	/* clear addr values, ec_parse_io_ports depend on it */
786 	ec->command_addr = ec->data_addr = 0;
787 
788 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
789 				     ec_parse_io_ports, ec);
790 	if (ACPI_FAILURE(status))
791 		return status;
792 
793 	/* Get GPE bit assignment (EC events). */
794 	/* TODO: Add support for _GPE returning a package */
795 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
796 	if (ACPI_FAILURE(status))
797 		return status;
798 	ec->gpe = tmp;
799 	/* Use the global lock for all EC transactions? */
800 	tmp = 0;
801 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
802 	ec->global_lock = tmp;
803 	ec->handle = handle;
804 	return AE_CTRL_TERMINATE;
805 }
806 
807 static int ec_install_handlers(struct acpi_ec *ec)
808 {
809 	acpi_status status;
810 
811 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
812 		return 0;
813 	status = acpi_install_gpe_handler(NULL, ec->gpe,
814 				  ACPI_GPE_EDGE_TRIGGERED,
815 				  &acpi_ec_gpe_handler, ec);
816 	if (ACPI_FAILURE(status))
817 		return -ENODEV;
818 
819 	acpi_enable_gpe(NULL, ec->gpe);
820 	status = acpi_install_address_space_handler(ec->handle,
821 						    ACPI_ADR_SPACE_EC,
822 						    &acpi_ec_space_handler,
823 						    NULL, ec);
824 	if (ACPI_FAILURE(status)) {
825 		if (status == AE_NOT_FOUND) {
826 			/*
827 			 * Maybe OS fails in evaluating the _REG object.
828 			 * The AE_NOT_FOUND error will be ignored and OS
829 			 * continue to initialize EC.
830 			 */
831 			pr_err("Fail in evaluating the _REG object"
832 				" of EC device. Broken bios is suspected.\n");
833 		} else {
834 			acpi_disable_gpe(NULL, ec->gpe);
835 			acpi_remove_gpe_handler(NULL, ec->gpe,
836 				&acpi_ec_gpe_handler);
837 			return -ENODEV;
838 		}
839 	}
840 
841 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
842 	return 0;
843 }
844 
845 static void ec_remove_handlers(struct acpi_ec *ec)
846 {
847 	if (!test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
848 		return;
849 	acpi_disable_gpe(NULL, ec->gpe);
850 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
851 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
852 		pr_err("failed to remove space handler\n");
853 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
854 				&acpi_ec_gpe_handler)))
855 		pr_err("failed to remove gpe handler\n");
856 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
857 }
858 
859 static int acpi_ec_add(struct acpi_device *device)
860 {
861 	struct acpi_ec *ec = NULL;
862 	int ret;
863 
864 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
865 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
866 
867 	/* Check for boot EC */
868 	if (boot_ec &&
869 	    (boot_ec->handle == device->handle ||
870 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
871 		ec = boot_ec;
872 		boot_ec = NULL;
873 	} else {
874 		ec = make_acpi_ec();
875 		if (!ec)
876 			return -ENOMEM;
877 	}
878 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
879 		AE_CTRL_TERMINATE) {
880 			kfree(ec);
881 			return -EINVAL;
882 	}
883 
884 	/* Find and register all query methods */
885 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
886 			    acpi_ec_register_query_methods, NULL, ec, NULL);
887 
888 	if (!first_ec)
889 		first_ec = ec;
890 	device->driver_data = ec;
891 
892 	ret = !!request_region(ec->data_addr, 1, "EC data");
893 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
894 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
895 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
896 
897 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
898 			  ec->gpe, ec->command_addr, ec->data_addr);
899 
900 	ret = ec_install_handlers(ec);
901 
902 	/* EC is fully operational, allow queries */
903 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
904 
905 	/* Clear stale _Q events if hardware might require that */
906 	if (EC_FLAGS_CLEAR_ON_RESUME) {
907 		mutex_lock(&ec->mutex);
908 		acpi_ec_clear(ec);
909 		mutex_unlock(&ec->mutex);
910 	}
911 	return ret;
912 }
913 
914 static int acpi_ec_remove(struct acpi_device *device)
915 {
916 	struct acpi_ec *ec;
917 	struct acpi_ec_query_handler *handler, *tmp;
918 
919 	if (!device)
920 		return -EINVAL;
921 
922 	ec = acpi_driver_data(device);
923 	ec_remove_handlers(ec);
924 	mutex_lock(&ec->mutex);
925 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
926 		list_del(&handler->node);
927 		kfree(handler);
928 	}
929 	mutex_unlock(&ec->mutex);
930 	release_region(ec->data_addr, 1);
931 	release_region(ec->command_addr, 1);
932 	device->driver_data = NULL;
933 	if (ec == first_ec)
934 		first_ec = NULL;
935 	kfree(ec);
936 	return 0;
937 }
938 
939 static acpi_status
940 ec_parse_io_ports(struct acpi_resource *resource, void *context)
941 {
942 	struct acpi_ec *ec = context;
943 
944 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
945 		return AE_OK;
946 
947 	/*
948 	 * The first address region returned is the data port, and
949 	 * the second address region returned is the status/command
950 	 * port.
951 	 */
952 	if (ec->data_addr == 0)
953 		ec->data_addr = resource->data.io.minimum;
954 	else if (ec->command_addr == 0)
955 		ec->command_addr = resource->data.io.minimum;
956 	else
957 		return AE_CTRL_TERMINATE;
958 
959 	return AE_OK;
960 }
961 
962 int __init acpi_boot_ec_enable(void)
963 {
964 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
965 		return 0;
966 	if (!ec_install_handlers(boot_ec)) {
967 		first_ec = boot_ec;
968 		return 0;
969 	}
970 	return -EFAULT;
971 }
972 
973 static const struct acpi_device_id ec_device_ids[] = {
974 	{"PNP0C09", 0},
975 	{"", 0},
976 };
977 
978 /* Some BIOS do not survive early DSDT scan, skip it */
979 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
980 {
981 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
982 	return 0;
983 }
984 
985 /* ASUStek often supplies us with broken ECDT, validate it */
986 static int ec_validate_ecdt(const struct dmi_system_id *id)
987 {
988 	EC_FLAGS_VALIDATE_ECDT = 1;
989 	return 0;
990 }
991 
992 /* MSI EC needs special treatment, enable it */
993 static int ec_flag_msi(const struct dmi_system_id *id)
994 {
995 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
996 	EC_FLAGS_MSI = 1;
997 	EC_FLAGS_VALIDATE_ECDT = 1;
998 	return 0;
999 }
1000 
1001 /*
1002  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
1003  * the GPE storm threshold back to 20
1004  */
1005 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
1006 {
1007 	pr_debug("Setting the EC GPE storm threshold to 20\n");
1008 	ec_storm_threshold  = 20;
1009 	return 0;
1010 }
1011 
1012 /*
1013  * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
1014  * which case, we complete the QR_EC without issuing it to the firmware.
1015  * https://bugzilla.kernel.org/show_bug.cgi?id=86211
1016  */
1017 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1018 {
1019 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1020 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1021 	return 0;
1022 }
1023 
1024 /*
1025  * On some hardware it is necessary to clear events accumulated by the EC during
1026  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1027  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1028  *
1029  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1030  *
1031  * Ideally, the EC should also be instructed NOT to accumulate events during
1032  * sleep (which Windows seems to do somehow), but the interface to control this
1033  * behaviour is not known at this time.
1034  *
1035  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1036  * however it is very likely that other Samsung models are affected.
1037  *
1038  * On systems which don't accumulate _Q events during sleep, this extra check
1039  * should be harmless.
1040  */
1041 static int ec_clear_on_resume(const struct dmi_system_id *id)
1042 {
1043 	pr_debug("Detected system needing EC poll on resume.\n");
1044 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1045 	return 0;
1046 }
1047 
1048 static struct dmi_system_id ec_dmi_table[] __initdata = {
1049 	{
1050 	ec_skip_dsdt_scan, "Compal JFL92", {
1051 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
1052 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
1053 	{
1054 	ec_flag_msi, "MSI hardware", {
1055 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1056 	{
1057 	ec_flag_msi, "MSI hardware", {
1058 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
1059 	{
1060 	ec_flag_msi, "MSI hardware", {
1061 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1062 	{
1063 	ec_flag_msi, "MSI hardware", {
1064 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1065 	{
1066 	ec_flag_msi, "Quanta hardware", {
1067 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1068 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1069 	{
1070 	ec_flag_msi, "Quanta hardware", {
1071 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1072 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1073 	{
1074 	ec_flag_msi, "Clevo W350etq", {
1075 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO CO."),
1076 	DMI_MATCH(DMI_PRODUCT_NAME, "W35_37ET"),}, NULL},
1077 	{
1078 	ec_validate_ecdt, "ASUS hardware", {
1079 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1080 	{
1081 	ec_validate_ecdt, "ASUS hardware", {
1082 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1083 	{
1084 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1085 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1086 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1087 	{
1088 	ec_skip_dsdt_scan, "HP Folio 13", {
1089 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1090 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1091 	{
1092 	ec_validate_ecdt, "ASUS hardware", {
1093 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1094 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1095 	{
1096 	ec_clear_on_resume, "Samsung hardware", {
1097 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1098 	{
1099 	ec_flag_query_handshake, "Acer hardware", {
1100 	DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
1101 	{},
1102 };
1103 
1104 int __init acpi_ec_ecdt_probe(void)
1105 {
1106 	acpi_status status;
1107 	struct acpi_ec *saved_ec = NULL;
1108 	struct acpi_table_ecdt *ecdt_ptr;
1109 
1110 	boot_ec = make_acpi_ec();
1111 	if (!boot_ec)
1112 		return -ENOMEM;
1113 	/*
1114 	 * Generate a boot ec context
1115 	 */
1116 	dmi_check_system(ec_dmi_table);
1117 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1118 				(struct acpi_table_header **)&ecdt_ptr);
1119 	if (ACPI_SUCCESS(status)) {
1120 		pr_info("EC description table is found, configuring boot EC\n");
1121 		boot_ec->command_addr = ecdt_ptr->control.address;
1122 		boot_ec->data_addr = ecdt_ptr->data.address;
1123 		boot_ec->gpe = ecdt_ptr->gpe;
1124 		boot_ec->handle = ACPI_ROOT_OBJECT;
1125 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id,
1126 				&boot_ec->handle);
1127 		/* Don't trust ECDT, which comes from ASUSTek */
1128 		if (!EC_FLAGS_VALIDATE_ECDT)
1129 			goto install;
1130 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1131 		if (!saved_ec)
1132 			return -ENOMEM;
1133 	/* fall through */
1134 	}
1135 
1136 	if (EC_FLAGS_SKIP_DSDT_SCAN) {
1137 		kfree(saved_ec);
1138 		return -ENODEV;
1139 	}
1140 
1141 	/* This workaround is needed only on some broken machines,
1142 	 * which require early EC, but fail to provide ECDT */
1143 	pr_debug("Look up EC in DSDT\n");
1144 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1145 					boot_ec, NULL);
1146 	/* Check that acpi_get_devices actually find something */
1147 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1148 		goto error;
1149 	if (saved_ec) {
1150 		/* try to find good ECDT from ASUSTek */
1151 		if (saved_ec->command_addr != boot_ec->command_addr ||
1152 		    saved_ec->data_addr != boot_ec->data_addr ||
1153 		    saved_ec->gpe != boot_ec->gpe ||
1154 		    saved_ec->handle != boot_ec->handle)
1155 			pr_info("ASUSTek keeps feeding us with broken "
1156 			"ECDT tables, which are very hard to workaround. "
1157 			"Trying to use DSDT EC info instead. Please send "
1158 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1159 		kfree(saved_ec);
1160 		saved_ec = NULL;
1161 	} else {
1162 		/* We really need to limit this workaround, the only ASUS,
1163 		* which needs it, has fake EC._INI method, so use it as flag.
1164 		* Keep boot_ec struct as it will be needed soon.
1165 		*/
1166 		if (!dmi_name_in_vendors("ASUS") ||
1167 		    !acpi_has_method(boot_ec->handle, "_INI"))
1168 			return -ENODEV;
1169 	}
1170 install:
1171 	if (!ec_install_handlers(boot_ec)) {
1172 		first_ec = boot_ec;
1173 		return 0;
1174 	}
1175 error:
1176 	kfree(boot_ec);
1177 	kfree(saved_ec);
1178 	boot_ec = NULL;
1179 	return -ENODEV;
1180 }
1181 
1182 static struct acpi_driver acpi_ec_driver = {
1183 	.name = "ec",
1184 	.class = ACPI_EC_CLASS,
1185 	.ids = ec_device_ids,
1186 	.ops = {
1187 		.add = acpi_ec_add,
1188 		.remove = acpi_ec_remove,
1189 		},
1190 };
1191 
1192 int __init acpi_ec_init(void)
1193 {
1194 	int result = 0;
1195 
1196 	/* Now register the driver for the EC */
1197 	result = acpi_bus_register_driver(&acpi_ec_driver);
1198 	if (result < 0)
1199 		return -ENODEV;
1200 
1201 	return result;
1202 }
1203 
1204 /* EC driver currently not unloadable */
1205 #if 0
1206 static void __exit acpi_ec_exit(void)
1207 {
1208 
1209 	acpi_bus_unregister_driver(&acpi_ec_driver);
1210 }
1211 #endif	/* 0 */
1212