xref: /linux/drivers/acpi/ec.c (revision c98be0c96db00e9b6b02d31e0fa7590c54cdaaac)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v2.1)
3  *
4  *  Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@suse.de>
5  *  Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>
6  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
7  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
8  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
9  *
10  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11  *
12  *  This program is free software; you can redistribute it and/or modify
13  *  it under the terms of the GNU General Public License as published by
14  *  the Free Software Foundation; either version 2 of the License, or (at
15  *  your option) any later version.
16  *
17  *  This program is distributed in the hope that it will be useful, but
18  *  WITHOUT ANY WARRANTY; without even the implied warranty of
19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  *  General Public License for more details.
21  *
22  *  You should have received a copy of the GNU General Public License along
23  *  with this program; if not, write to the Free Software Foundation, Inc.,
24  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25  *
26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27  */
28 
29 /* Uncomment next line to get verbose printout */
30 /* #define DEBUG */
31 #define pr_fmt(fmt) "ACPI : EC: " fmt
32 
33 #include <linux/kernel.h>
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/delay.h>
38 #include <linux/interrupt.h>
39 #include <linux/list.h>
40 #include <linux/spinlock.h>
41 #include <linux/slab.h>
42 #include <linux/acpi.h>
43 #include <linux/dmi.h>
44 #include <asm/io.h>
45 
46 #include "internal.h"
47 
48 #define ACPI_EC_CLASS			"embedded_controller"
49 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
50 #define ACPI_EC_FILE_INFO		"info"
51 
52 /* EC status register */
53 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
54 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
55 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
56 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
57 
58 /* EC commands */
59 enum ec_command {
60 	ACPI_EC_COMMAND_READ = 0x80,
61 	ACPI_EC_COMMAND_WRITE = 0x81,
62 	ACPI_EC_BURST_ENABLE = 0x82,
63 	ACPI_EC_BURST_DISABLE = 0x83,
64 	ACPI_EC_COMMAND_QUERY = 0x84,
65 };
66 
67 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
68 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
69 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
70 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
71 					 * when trying to clear the EC */
72 
73 enum {
74 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
75 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
76 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
77 					 * OpReg are installed */
78 	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
79 };
80 
81 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
82 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
83 module_param(ec_delay, uint, 0644);
84 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
85 
86 /*
87  * If the number of false interrupts per one transaction exceeds
88  * this threshold, will think there is a GPE storm happened and
89  * will disable the GPE for normal transaction.
90  */
91 static unsigned int ec_storm_threshold  __read_mostly = 8;
92 module_param(ec_storm_threshold, uint, 0644);
93 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
94 
95 struct acpi_ec_query_handler {
96 	struct list_head node;
97 	acpi_ec_query_func func;
98 	acpi_handle handle;
99 	void *data;
100 	u8 query_bit;
101 };
102 
103 struct transaction {
104 	const u8 *wdata;
105 	u8 *rdata;
106 	unsigned short irq_count;
107 	u8 command;
108 	u8 wi;
109 	u8 ri;
110 	u8 wlen;
111 	u8 rlen;
112 	bool done;
113 };
114 
115 struct acpi_ec *boot_ec, *first_ec;
116 EXPORT_SYMBOL(first_ec);
117 
118 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
119 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
120 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
121 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
122 
123 /* --------------------------------------------------------------------------
124                              Transaction Management
125    -------------------------------------------------------------------------- */
126 
127 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
128 {
129 	u8 x = inb(ec->command_addr);
130 	pr_debug("---> status = 0x%2.2x\n", x);
131 	return x;
132 }
133 
134 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
135 {
136 	u8 x = inb(ec->data_addr);
137 	pr_debug("---> data = 0x%2.2x\n", x);
138 	return x;
139 }
140 
141 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
142 {
143 	pr_debug("<--- command = 0x%2.2x\n", command);
144 	outb(command, ec->command_addr);
145 }
146 
147 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
148 {
149 	pr_debug("<--- data = 0x%2.2x\n", data);
150 	outb(data, ec->data_addr);
151 }
152 
153 static int ec_transaction_done(struct acpi_ec *ec)
154 {
155 	unsigned long flags;
156 	int ret = 0;
157 	spin_lock_irqsave(&ec->lock, flags);
158 	if (!ec->curr || ec->curr->done)
159 		ret = 1;
160 	spin_unlock_irqrestore(&ec->lock, flags);
161 	return ret;
162 }
163 
164 static void start_transaction(struct acpi_ec *ec)
165 {
166 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
167 	ec->curr->done = false;
168 	acpi_ec_write_cmd(ec, ec->curr->command);
169 }
170 
171 static void advance_transaction(struct acpi_ec *ec, u8 status)
172 {
173 	unsigned long flags;
174 	struct transaction *t;
175 
176 	spin_lock_irqsave(&ec->lock, flags);
177 	t = ec->curr;
178 	if (!t)
179 		goto unlock;
180 	if (t->wlen > t->wi) {
181 		if ((status & ACPI_EC_FLAG_IBF) == 0)
182 			acpi_ec_write_data(ec,
183 				t->wdata[t->wi++]);
184 		else
185 			goto err;
186 	} else if (t->rlen > t->ri) {
187 		if ((status & ACPI_EC_FLAG_OBF) == 1) {
188 			t->rdata[t->ri++] = acpi_ec_read_data(ec);
189 			if (t->rlen == t->ri)
190 				t->done = true;
191 		} else
192 			goto err;
193 	} else if (t->wlen == t->wi &&
194 		   (status & ACPI_EC_FLAG_IBF) == 0)
195 		t->done = true;
196 	goto unlock;
197 err:
198 	/*
199 	 * If SCI bit is set, then don't think it's a false IRQ
200 	 * otherwise will take a not handled IRQ as a false one.
201 	 */
202 	if (in_interrupt() && !(status & ACPI_EC_FLAG_SCI))
203 		++t->irq_count;
204 
205 unlock:
206 	spin_unlock_irqrestore(&ec->lock, flags);
207 }
208 
209 static int acpi_ec_sync_query(struct acpi_ec *ec);
210 
211 static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
212 {
213 	if (state & ACPI_EC_FLAG_SCI) {
214 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
215 			return acpi_ec_sync_query(ec);
216 	}
217 	return 0;
218 }
219 
220 static int ec_poll(struct acpi_ec *ec)
221 {
222 	unsigned long flags;
223 	int repeat = 5; /* number of command restarts */
224 	while (repeat--) {
225 		unsigned long delay = jiffies +
226 			msecs_to_jiffies(ec_delay);
227 		do {
228 			/* don't sleep with disabled interrupts */
229 			if (EC_FLAGS_MSI || irqs_disabled()) {
230 				udelay(ACPI_EC_MSI_UDELAY);
231 				if (ec_transaction_done(ec))
232 					return 0;
233 			} else {
234 				if (wait_event_timeout(ec->wait,
235 						ec_transaction_done(ec),
236 						msecs_to_jiffies(1)))
237 					return 0;
238 			}
239 			advance_transaction(ec, acpi_ec_read_status(ec));
240 		} while (time_before(jiffies, delay));
241 		pr_debug("controller reset, restart transaction\n");
242 		spin_lock_irqsave(&ec->lock, flags);
243 		start_transaction(ec);
244 		spin_unlock_irqrestore(&ec->lock, flags);
245 	}
246 	return -ETIME;
247 }
248 
249 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
250 					struct transaction *t)
251 {
252 	unsigned long tmp;
253 	int ret = 0;
254 	if (EC_FLAGS_MSI)
255 		udelay(ACPI_EC_MSI_UDELAY);
256 	/* start transaction */
257 	spin_lock_irqsave(&ec->lock, tmp);
258 	/* following two actions should be kept atomic */
259 	ec->curr = t;
260 	start_transaction(ec);
261 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
262 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
263 	spin_unlock_irqrestore(&ec->lock, tmp);
264 	ret = ec_poll(ec);
265 	spin_lock_irqsave(&ec->lock, tmp);
266 	ec->curr = NULL;
267 	spin_unlock_irqrestore(&ec->lock, tmp);
268 	return ret;
269 }
270 
271 static int ec_check_ibf0(struct acpi_ec *ec)
272 {
273 	u8 status = acpi_ec_read_status(ec);
274 	return (status & ACPI_EC_FLAG_IBF) == 0;
275 }
276 
277 static int ec_wait_ibf0(struct acpi_ec *ec)
278 {
279 	unsigned long delay = jiffies + msecs_to_jiffies(ec_delay);
280 	/* interrupt wait manually if GPE mode is not active */
281 	while (time_before(jiffies, delay))
282 		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
283 					msecs_to_jiffies(1)))
284 			return 0;
285 	return -ETIME;
286 }
287 
288 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
289 {
290 	int status;
291 	u32 glk;
292 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
293 		return -EINVAL;
294 	if (t->rdata)
295 		memset(t->rdata, 0, t->rlen);
296 	mutex_lock(&ec->mutex);
297 	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
298 		status = -EINVAL;
299 		goto unlock;
300 	}
301 	if (ec->global_lock) {
302 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
303 		if (ACPI_FAILURE(status)) {
304 			status = -ENODEV;
305 			goto unlock;
306 		}
307 	}
308 	if (ec_wait_ibf0(ec)) {
309 		pr_err("input buffer is not empty, "
310 				"aborting transaction\n");
311 		status = -ETIME;
312 		goto end;
313 	}
314 	pr_debug("transaction start (cmd=0x%02x, addr=0x%02x)\n",
315 			t->command, t->wdata ? t->wdata[0] : 0);
316 	/* disable GPE during transaction if storm is detected */
317 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
318 		/* It has to be disabled, so that it doesn't trigger. */
319 		acpi_disable_gpe(NULL, ec->gpe);
320 	}
321 
322 	status = acpi_ec_transaction_unlocked(ec, t);
323 
324 	/* check if we received SCI during transaction */
325 	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
326 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
327 		msleep(1);
328 		/* It is safe to enable the GPE outside of the transaction. */
329 		acpi_enable_gpe(NULL, ec->gpe);
330 	} else if (t->irq_count > ec_storm_threshold) {
331 		pr_info("GPE storm detected(%d GPEs), "
332 			"transactions will use polling mode\n",
333 			t->irq_count);
334 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
335 	}
336 	pr_debug("transaction end\n");
337 end:
338 	if (ec->global_lock)
339 		acpi_release_global_lock(glk);
340 unlock:
341 	mutex_unlock(&ec->mutex);
342 	return status;
343 }
344 
345 static int acpi_ec_burst_enable(struct acpi_ec *ec)
346 {
347 	u8 d;
348 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
349 				.wdata = NULL, .rdata = &d,
350 				.wlen = 0, .rlen = 1};
351 
352 	return acpi_ec_transaction(ec, &t);
353 }
354 
355 static int acpi_ec_burst_disable(struct acpi_ec *ec)
356 {
357 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
358 				.wdata = NULL, .rdata = NULL,
359 				.wlen = 0, .rlen = 0};
360 
361 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
362 				acpi_ec_transaction(ec, &t) : 0;
363 }
364 
365 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
366 {
367 	int result;
368 	u8 d;
369 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
370 				.wdata = &address, .rdata = &d,
371 				.wlen = 1, .rlen = 1};
372 
373 	result = acpi_ec_transaction(ec, &t);
374 	*data = d;
375 	return result;
376 }
377 
378 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
379 {
380 	u8 wdata[2] = { address, data };
381 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
382 				.wdata = wdata, .rdata = NULL,
383 				.wlen = 2, .rlen = 0};
384 
385 	return acpi_ec_transaction(ec, &t);
386 }
387 
388 int ec_read(u8 addr, u8 *val)
389 {
390 	int err;
391 	u8 temp_data;
392 
393 	if (!first_ec)
394 		return -ENODEV;
395 
396 	err = acpi_ec_read(first_ec, addr, &temp_data);
397 
398 	if (!err) {
399 		*val = temp_data;
400 		return 0;
401 	} else
402 		return err;
403 }
404 
405 EXPORT_SYMBOL(ec_read);
406 
407 int ec_write(u8 addr, u8 val)
408 {
409 	int err;
410 
411 	if (!first_ec)
412 		return -ENODEV;
413 
414 	err = acpi_ec_write(first_ec, addr, val);
415 
416 	return err;
417 }
418 
419 EXPORT_SYMBOL(ec_write);
420 
421 int ec_transaction(u8 command,
422 		   const u8 * wdata, unsigned wdata_len,
423 		   u8 * rdata, unsigned rdata_len)
424 {
425 	struct transaction t = {.command = command,
426 				.wdata = wdata, .rdata = rdata,
427 				.wlen = wdata_len, .rlen = rdata_len};
428 	if (!first_ec)
429 		return -ENODEV;
430 
431 	return acpi_ec_transaction(first_ec, &t);
432 }
433 
434 EXPORT_SYMBOL(ec_transaction);
435 
436 /* Get the handle to the EC device */
437 acpi_handle ec_get_handle(void)
438 {
439 	if (!first_ec)
440 		return NULL;
441 	return first_ec->handle;
442 }
443 
444 EXPORT_SYMBOL(ec_get_handle);
445 
446 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data);
447 
448 /*
449  * Clears stale _Q events that might have accumulated in the EC.
450  * Run with locked ec mutex.
451  */
452 static void acpi_ec_clear(struct acpi_ec *ec)
453 {
454 	int i, status;
455 	u8 value = 0;
456 
457 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
458 		status = acpi_ec_query_unlocked(ec, &value);
459 		if (status || !value)
460 			break;
461 	}
462 
463 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
464 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
465 	else
466 		pr_info("%d stale EC events cleared\n", i);
467 }
468 
469 void acpi_ec_block_transactions(void)
470 {
471 	struct acpi_ec *ec = first_ec;
472 
473 	if (!ec)
474 		return;
475 
476 	mutex_lock(&ec->mutex);
477 	/* Prevent transactions from being carried out */
478 	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
479 	mutex_unlock(&ec->mutex);
480 }
481 
482 void acpi_ec_unblock_transactions(void)
483 {
484 	struct acpi_ec *ec = first_ec;
485 
486 	if (!ec)
487 		return;
488 
489 	mutex_lock(&ec->mutex);
490 	/* Allow transactions to be carried out again */
491 	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
492 
493 	if (EC_FLAGS_CLEAR_ON_RESUME)
494 		acpi_ec_clear(ec);
495 
496 	mutex_unlock(&ec->mutex);
497 }
498 
499 void acpi_ec_unblock_transactions_early(void)
500 {
501 	/*
502 	 * Allow transactions to happen again (this function is called from
503 	 * atomic context during wakeup, so we don't need to acquire the mutex).
504 	 */
505 	if (first_ec)
506 		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
507 }
508 
509 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
510 {
511 	int result;
512 	u8 d;
513 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
514 				.wdata = NULL, .rdata = &d,
515 				.wlen = 0, .rlen = 1};
516 	if (!ec || !data)
517 		return -EINVAL;
518 	/*
519 	 * Query the EC to find out which _Qxx method we need to evaluate.
520 	 * Note that successful completion of the query causes the ACPI_EC_SCI
521 	 * bit to be cleared (and thus clearing the interrupt source).
522 	 */
523 	result = acpi_ec_transaction_unlocked(ec, &t);
524 	if (result)
525 		return result;
526 	if (!d)
527 		return -ENODATA;
528 	*data = d;
529 	return 0;
530 }
531 
532 /* --------------------------------------------------------------------------
533                                 Event Management
534    -------------------------------------------------------------------------- */
535 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
536 			      acpi_handle handle, acpi_ec_query_func func,
537 			      void *data)
538 {
539 	struct acpi_ec_query_handler *handler =
540 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
541 	if (!handler)
542 		return -ENOMEM;
543 
544 	handler->query_bit = query_bit;
545 	handler->handle = handle;
546 	handler->func = func;
547 	handler->data = data;
548 	mutex_lock(&ec->mutex);
549 	list_add(&handler->node, &ec->list);
550 	mutex_unlock(&ec->mutex);
551 	return 0;
552 }
553 
554 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
555 
556 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
557 {
558 	struct acpi_ec_query_handler *handler, *tmp;
559 	mutex_lock(&ec->mutex);
560 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
561 		if (query_bit == handler->query_bit) {
562 			list_del(&handler->node);
563 			kfree(handler);
564 		}
565 	}
566 	mutex_unlock(&ec->mutex);
567 }
568 
569 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
570 
571 static void acpi_ec_run(void *cxt)
572 {
573 	struct acpi_ec_query_handler *handler = cxt;
574 	if (!handler)
575 		return;
576 	pr_debug("start query execution\n");
577 	if (handler->func)
578 		handler->func(handler->data);
579 	else if (handler->handle)
580 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
581 	pr_debug("stop query execution\n");
582 	kfree(handler);
583 }
584 
585 static int acpi_ec_sync_query(struct acpi_ec *ec)
586 {
587 	u8 value = 0;
588 	int status;
589 	struct acpi_ec_query_handler *handler, *copy;
590 	if ((status = acpi_ec_query_unlocked(ec, &value)))
591 		return status;
592 	list_for_each_entry(handler, &ec->list, node) {
593 		if (value == handler->query_bit) {
594 			/* have custom handler for this bit */
595 			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
596 			if (!copy)
597 				return -ENOMEM;
598 			memcpy(copy, handler, sizeof(*copy));
599 			pr_debug("push query execution (0x%2x) on queue\n",
600 				value);
601 			return acpi_os_execute((copy->func) ?
602 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
603 				acpi_ec_run, copy);
604 		}
605 	}
606 	return 0;
607 }
608 
609 static void acpi_ec_gpe_query(void *ec_cxt)
610 {
611 	struct acpi_ec *ec = ec_cxt;
612 	if (!ec)
613 		return;
614 	mutex_lock(&ec->mutex);
615 	acpi_ec_sync_query(ec);
616 	mutex_unlock(&ec->mutex);
617 }
618 
619 static int ec_check_sci(struct acpi_ec *ec, u8 state)
620 {
621 	if (state & ACPI_EC_FLAG_SCI) {
622 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
623 			pr_debug("push gpe query to the queue\n");
624 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
625 				acpi_ec_gpe_query, ec);
626 		}
627 	}
628 	return 0;
629 }
630 
631 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
632 	u32 gpe_number, void *data)
633 {
634 	struct acpi_ec *ec = data;
635 	u8 status = acpi_ec_read_status(ec);
636 
637 	pr_debug("~~~> interrupt, status:0x%02x\n", status);
638 
639 	advance_transaction(ec, status);
640 	if (ec_transaction_done(ec) &&
641 	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
642 		wake_up(&ec->wait);
643 		ec_check_sci(ec, acpi_ec_read_status(ec));
644 	}
645 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
646 }
647 
648 /* --------------------------------------------------------------------------
649                              Address Space Management
650    -------------------------------------------------------------------------- */
651 
652 static acpi_status
653 acpi_ec_space_handler(u32 function, acpi_physical_address address,
654 		      u32 bits, u64 *value64,
655 		      void *handler_context, void *region_context)
656 {
657 	struct acpi_ec *ec = handler_context;
658 	int result = 0, i, bytes = bits / 8;
659 	u8 *value = (u8 *)value64;
660 
661 	if ((address > 0xFF) || !value || !handler_context)
662 		return AE_BAD_PARAMETER;
663 
664 	if (function != ACPI_READ && function != ACPI_WRITE)
665 		return AE_BAD_PARAMETER;
666 
667 	if (EC_FLAGS_MSI || bits > 8)
668 		acpi_ec_burst_enable(ec);
669 
670 	for (i = 0; i < bytes; ++i, ++address, ++value)
671 		result = (function == ACPI_READ) ?
672 			acpi_ec_read(ec, address, value) :
673 			acpi_ec_write(ec, address, *value);
674 
675 	if (EC_FLAGS_MSI || bits > 8)
676 		acpi_ec_burst_disable(ec);
677 
678 	switch (result) {
679 	case -EINVAL:
680 		return AE_BAD_PARAMETER;
681 		break;
682 	case -ENODEV:
683 		return AE_NOT_FOUND;
684 		break;
685 	case -ETIME:
686 		return AE_TIME;
687 		break;
688 	default:
689 		return AE_OK;
690 	}
691 }
692 
693 /* --------------------------------------------------------------------------
694                                Driver Interface
695    -------------------------------------------------------------------------- */
696 static acpi_status
697 ec_parse_io_ports(struct acpi_resource *resource, void *context);
698 
699 static struct acpi_ec *make_acpi_ec(void)
700 {
701 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
702 	if (!ec)
703 		return NULL;
704 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
705 	mutex_init(&ec->mutex);
706 	init_waitqueue_head(&ec->wait);
707 	INIT_LIST_HEAD(&ec->list);
708 	spin_lock_init(&ec->lock);
709 	return ec;
710 }
711 
712 static acpi_status
713 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
714 			       void *context, void **return_value)
715 {
716 	char node_name[5];
717 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
718 	struct acpi_ec *ec = context;
719 	int value = 0;
720 	acpi_status status;
721 
722 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
723 
724 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
725 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
726 	}
727 	return AE_OK;
728 }
729 
730 static acpi_status
731 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
732 {
733 	acpi_status status;
734 	unsigned long long tmp = 0;
735 
736 	struct acpi_ec *ec = context;
737 
738 	/* clear addr values, ec_parse_io_ports depend on it */
739 	ec->command_addr = ec->data_addr = 0;
740 
741 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
742 				     ec_parse_io_ports, ec);
743 	if (ACPI_FAILURE(status))
744 		return status;
745 
746 	/* Get GPE bit assignment (EC events). */
747 	/* TODO: Add support for _GPE returning a package */
748 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
749 	if (ACPI_FAILURE(status))
750 		return status;
751 	ec->gpe = tmp;
752 	/* Use the global lock for all EC transactions? */
753 	tmp = 0;
754 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
755 	ec->global_lock = tmp;
756 	ec->handle = handle;
757 	return AE_CTRL_TERMINATE;
758 }
759 
760 static int ec_install_handlers(struct acpi_ec *ec)
761 {
762 	acpi_status status;
763 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
764 		return 0;
765 	status = acpi_install_gpe_handler(NULL, ec->gpe,
766 				  ACPI_GPE_EDGE_TRIGGERED,
767 				  &acpi_ec_gpe_handler, ec);
768 	if (ACPI_FAILURE(status))
769 		return -ENODEV;
770 
771 	acpi_enable_gpe(NULL, ec->gpe);
772 	status = acpi_install_address_space_handler(ec->handle,
773 						    ACPI_ADR_SPACE_EC,
774 						    &acpi_ec_space_handler,
775 						    NULL, ec);
776 	if (ACPI_FAILURE(status)) {
777 		if (status == AE_NOT_FOUND) {
778 			/*
779 			 * Maybe OS fails in evaluating the _REG object.
780 			 * The AE_NOT_FOUND error will be ignored and OS
781 			 * continue to initialize EC.
782 			 */
783 			pr_err("Fail in evaluating the _REG object"
784 				" of EC device. Broken bios is suspected.\n");
785 		} else {
786 			acpi_disable_gpe(NULL, ec->gpe);
787 			acpi_remove_gpe_handler(NULL, ec->gpe,
788 				&acpi_ec_gpe_handler);
789 			return -ENODEV;
790 		}
791 	}
792 
793 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
794 	return 0;
795 }
796 
797 static void ec_remove_handlers(struct acpi_ec *ec)
798 {
799 	acpi_disable_gpe(NULL, ec->gpe);
800 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
801 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
802 		pr_err("failed to remove space handler\n");
803 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
804 				&acpi_ec_gpe_handler)))
805 		pr_err("failed to remove gpe handler\n");
806 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
807 }
808 
809 static int acpi_ec_add(struct acpi_device *device)
810 {
811 	struct acpi_ec *ec = NULL;
812 	int ret;
813 
814 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
815 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
816 
817 	/* Check for boot EC */
818 	if (boot_ec &&
819 	    (boot_ec->handle == device->handle ||
820 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
821 		ec = boot_ec;
822 		boot_ec = NULL;
823 	} else {
824 		ec = make_acpi_ec();
825 		if (!ec)
826 			return -ENOMEM;
827 	}
828 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
829 		AE_CTRL_TERMINATE) {
830 			kfree(ec);
831 			return -EINVAL;
832 	}
833 
834 	/* Find and register all query methods */
835 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
836 			    acpi_ec_register_query_methods, NULL, ec, NULL);
837 
838 	if (!first_ec)
839 		first_ec = ec;
840 	device->driver_data = ec;
841 
842 	ret = !!request_region(ec->data_addr, 1, "EC data");
843 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
844 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
845 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
846 
847 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
848 			  ec->gpe, ec->command_addr, ec->data_addr);
849 
850 	ret = ec_install_handlers(ec);
851 
852 	/* EC is fully operational, allow queries */
853 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
854 
855 	/* Clear stale _Q events if hardware might require that */
856 	if (EC_FLAGS_CLEAR_ON_RESUME) {
857 		mutex_lock(&ec->mutex);
858 		acpi_ec_clear(ec);
859 		mutex_unlock(&ec->mutex);
860 	}
861 	return ret;
862 }
863 
864 static int acpi_ec_remove(struct acpi_device *device)
865 {
866 	struct acpi_ec *ec;
867 	struct acpi_ec_query_handler *handler, *tmp;
868 
869 	if (!device)
870 		return -EINVAL;
871 
872 	ec = acpi_driver_data(device);
873 	ec_remove_handlers(ec);
874 	mutex_lock(&ec->mutex);
875 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
876 		list_del(&handler->node);
877 		kfree(handler);
878 	}
879 	mutex_unlock(&ec->mutex);
880 	release_region(ec->data_addr, 1);
881 	release_region(ec->command_addr, 1);
882 	device->driver_data = NULL;
883 	if (ec == first_ec)
884 		first_ec = NULL;
885 	kfree(ec);
886 	return 0;
887 }
888 
889 static acpi_status
890 ec_parse_io_ports(struct acpi_resource *resource, void *context)
891 {
892 	struct acpi_ec *ec = context;
893 
894 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
895 		return AE_OK;
896 
897 	/*
898 	 * The first address region returned is the data port, and
899 	 * the second address region returned is the status/command
900 	 * port.
901 	 */
902 	if (ec->data_addr == 0)
903 		ec->data_addr = resource->data.io.minimum;
904 	else if (ec->command_addr == 0)
905 		ec->command_addr = resource->data.io.minimum;
906 	else
907 		return AE_CTRL_TERMINATE;
908 
909 	return AE_OK;
910 }
911 
912 int __init acpi_boot_ec_enable(void)
913 {
914 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
915 		return 0;
916 	if (!ec_install_handlers(boot_ec)) {
917 		first_ec = boot_ec;
918 		return 0;
919 	}
920 	return -EFAULT;
921 }
922 
923 static const struct acpi_device_id ec_device_ids[] = {
924 	{"PNP0C09", 0},
925 	{"", 0},
926 };
927 
928 /* Some BIOS do not survive early DSDT scan, skip it */
929 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
930 {
931 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
932 	return 0;
933 }
934 
935 /* ASUStek often supplies us with broken ECDT, validate it */
936 static int ec_validate_ecdt(const struct dmi_system_id *id)
937 {
938 	EC_FLAGS_VALIDATE_ECDT = 1;
939 	return 0;
940 }
941 
942 /* MSI EC needs special treatment, enable it */
943 static int ec_flag_msi(const struct dmi_system_id *id)
944 {
945 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
946 	EC_FLAGS_MSI = 1;
947 	EC_FLAGS_VALIDATE_ECDT = 1;
948 	return 0;
949 }
950 
951 /*
952  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
953  * the GPE storm threshold back to 20
954  */
955 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
956 {
957 	pr_debug("Setting the EC GPE storm threshold to 20\n");
958 	ec_storm_threshold  = 20;
959 	return 0;
960 }
961 
962 /*
963  * On some hardware it is necessary to clear events accumulated by the EC during
964  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
965  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
966  *
967  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
968  *
969  * Ideally, the EC should also be instructed NOT to accumulate events during
970  * sleep (which Windows seems to do somehow), but the interface to control this
971  * behaviour is not known at this time.
972  *
973  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
974  * however it is very likely that other Samsung models are affected.
975  *
976  * On systems which don't accumulate _Q events during sleep, this extra check
977  * should be harmless.
978  */
979 static int ec_clear_on_resume(const struct dmi_system_id *id)
980 {
981 	pr_debug("Detected system needing EC poll on resume.\n");
982 	EC_FLAGS_CLEAR_ON_RESUME = 1;
983 	return 0;
984 }
985 
986 static struct dmi_system_id ec_dmi_table[] __initdata = {
987 	{
988 	ec_skip_dsdt_scan, "Compal JFL92", {
989 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
990 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
991 	{
992 	ec_flag_msi, "MSI hardware", {
993 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
994 	{
995 	ec_flag_msi, "MSI hardware", {
996 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
997 	{
998 	ec_flag_msi, "MSI hardware", {
999 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
1000 	{
1001 	ec_flag_msi, "MSI hardware", {
1002 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1003 	{
1004 	ec_flag_msi, "Quanta hardware", {
1005 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1006 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1007 	{
1008 	ec_flag_msi, "Quanta hardware", {
1009 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1010 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1011 	{
1012 	ec_validate_ecdt, "ASUS hardware", {
1013 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1014 	{
1015 	ec_validate_ecdt, "ASUS hardware", {
1016 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1017 	{
1018 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1019 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1020 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1021 	{
1022 	ec_skip_dsdt_scan, "HP Folio 13", {
1023 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1024 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1025 	{
1026 	ec_validate_ecdt, "ASUS hardware", {
1027 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1028 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1029 	{
1030 	ec_clear_on_resume, "Samsung hardware", {
1031 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1032 	{},
1033 };
1034 
1035 int __init acpi_ec_ecdt_probe(void)
1036 {
1037 	acpi_status status;
1038 	struct acpi_ec *saved_ec = NULL;
1039 	struct acpi_table_ecdt *ecdt_ptr;
1040 
1041 	boot_ec = make_acpi_ec();
1042 	if (!boot_ec)
1043 		return -ENOMEM;
1044 	/*
1045 	 * Generate a boot ec context
1046 	 */
1047 	dmi_check_system(ec_dmi_table);
1048 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1049 				(struct acpi_table_header **)&ecdt_ptr);
1050 	if (ACPI_SUCCESS(status)) {
1051 		pr_info("EC description table is found, configuring boot EC\n");
1052 		boot_ec->command_addr = ecdt_ptr->control.address;
1053 		boot_ec->data_addr = ecdt_ptr->data.address;
1054 		boot_ec->gpe = ecdt_ptr->gpe;
1055 		boot_ec->handle = ACPI_ROOT_OBJECT;
1056 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
1057 		/* Don't trust ECDT, which comes from ASUSTek */
1058 		if (!EC_FLAGS_VALIDATE_ECDT)
1059 			goto install;
1060 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1061 		if (!saved_ec)
1062 			return -ENOMEM;
1063 	/* fall through */
1064 	}
1065 
1066 	if (EC_FLAGS_SKIP_DSDT_SCAN)
1067 		return -ENODEV;
1068 
1069 	/* This workaround is needed only on some broken machines,
1070 	 * which require early EC, but fail to provide ECDT */
1071 	pr_debug("Look up EC in DSDT\n");
1072 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1073 					boot_ec, NULL);
1074 	/* Check that acpi_get_devices actually find something */
1075 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1076 		goto error;
1077 	if (saved_ec) {
1078 		/* try to find good ECDT from ASUSTek */
1079 		if (saved_ec->command_addr != boot_ec->command_addr ||
1080 		    saved_ec->data_addr != boot_ec->data_addr ||
1081 		    saved_ec->gpe != boot_ec->gpe ||
1082 		    saved_ec->handle != boot_ec->handle)
1083 			pr_info("ASUSTek keeps feeding us with broken "
1084 			"ECDT tables, which are very hard to workaround. "
1085 			"Trying to use DSDT EC info instead. Please send "
1086 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1087 		kfree(saved_ec);
1088 		saved_ec = NULL;
1089 	} else {
1090 		/* We really need to limit this workaround, the only ASUS,
1091 		* which needs it, has fake EC._INI method, so use it as flag.
1092 		* Keep boot_ec struct as it will be needed soon.
1093 		*/
1094 		if (!dmi_name_in_vendors("ASUS") ||
1095 		    !acpi_has_method(boot_ec->handle, "_INI"))
1096 			return -ENODEV;
1097 	}
1098 install:
1099 	if (!ec_install_handlers(boot_ec)) {
1100 		first_ec = boot_ec;
1101 		return 0;
1102 	}
1103 error:
1104 	kfree(boot_ec);
1105 	boot_ec = NULL;
1106 	return -ENODEV;
1107 }
1108 
1109 static struct acpi_driver acpi_ec_driver = {
1110 	.name = "ec",
1111 	.class = ACPI_EC_CLASS,
1112 	.ids = ec_device_ids,
1113 	.ops = {
1114 		.add = acpi_ec_add,
1115 		.remove = acpi_ec_remove,
1116 		},
1117 };
1118 
1119 int __init acpi_ec_init(void)
1120 {
1121 	int result = 0;
1122 
1123 	/* Now register the driver for the EC */
1124 	result = acpi_bus_register_driver(&acpi_ec_driver);
1125 	if (result < 0)
1126 		return -ENODEV;
1127 
1128 	return result;
1129 }
1130 
1131 /* EC driver currently not unloadable */
1132 #if 0
1133 static void __exit acpi_ec_exit(void)
1134 {
1135 
1136 	acpi_bus_unregister_driver(&acpi_ec_driver);
1137 	return;
1138 }
1139 #endif	/* 0 */
1140