xref: /linux/drivers/acpi/ec.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
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 
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/init.h>
35 #include <linux/types.h>
36 #include <linux/delay.h>
37 #include <linux/interrupt.h>
38 #include <linux/list.h>
39 #include <linux/spinlock.h>
40 #include <linux/slab.h>
41 #include <asm/io.h>
42 #include <acpi/acpi_bus.h>
43 #include <acpi/acpi_drivers.h>
44 #include <linux/dmi.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 #undef PREFIX
53 #define PREFIX				"ACPI: EC: "
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_BURST	0x10	/* burst mode */
59 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
60 
61 /* EC commands */
62 enum ec_command {
63 	ACPI_EC_COMMAND_READ = 0x80,
64 	ACPI_EC_COMMAND_WRITE = 0x81,
65 	ACPI_EC_BURST_ENABLE = 0x82,
66 	ACPI_EC_BURST_DISABLE = 0x83,
67 	ACPI_EC_COMMAND_QUERY = 0x84,
68 };
69 
70 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
71 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
72 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
73 
74 #define ACPI_EC_STORM_THRESHOLD 8	/* number of false interrupts
75 					   per one transaction */
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 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
86 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
87 module_param(ec_delay, uint, 0644);
88 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
89 
90 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
91 /* External interfaces use first EC only, so remember */
92 typedef int (*acpi_ec_query_func) (void *data);
93 
94 struct acpi_ec_query_handler {
95 	struct list_head node;
96 	acpi_ec_query_func func;
97 	acpi_handle handle;
98 	void *data;
99 	u8 query_bit;
100 };
101 
102 struct transaction {
103 	const u8 *wdata;
104 	u8 *rdata;
105 	unsigned short irq_count;
106 	u8 command;
107 	u8 wi;
108 	u8 ri;
109 	u8 wlen;
110 	u8 rlen;
111 	bool done;
112 };
113 
114 struct acpi_ec *boot_ec, *first_ec;
115 EXPORT_SYMBOL(first_ec);
116 
117 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
118 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
119 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
120 
121 /* --------------------------------------------------------------------------
122                              Transaction Management
123    -------------------------------------------------------------------------- */
124 
125 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
126 {
127 	u8 x = inb(ec->command_addr);
128 	pr_debug(PREFIX "---> status = 0x%2.2x\n", x);
129 	return x;
130 }
131 
132 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
133 {
134 	u8 x = inb(ec->data_addr);
135 	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
136 	return x;
137 }
138 
139 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
140 {
141 	pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
142 	outb(command, ec->command_addr);
143 }
144 
145 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
146 {
147 	pr_debug(PREFIX "<--- data = 0x%2.2x\n", data);
148 	outb(data, ec->data_addr);
149 }
150 
151 static int ec_transaction_done(struct acpi_ec *ec)
152 {
153 	unsigned long flags;
154 	int ret = 0;
155 	spin_lock_irqsave(&ec->curr_lock, flags);
156 	if (!ec->curr || ec->curr->done)
157 		ret = 1;
158 	spin_unlock_irqrestore(&ec->curr_lock, flags);
159 	return ret;
160 }
161 
162 static void start_transaction(struct acpi_ec *ec)
163 {
164 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
165 	ec->curr->done = false;
166 	acpi_ec_write_cmd(ec, ec->curr->command);
167 }
168 
169 static void advance_transaction(struct acpi_ec *ec, u8 status)
170 {
171 	unsigned long flags;
172 	spin_lock_irqsave(&ec->curr_lock, flags);
173 	if (!ec->curr)
174 		goto unlock;
175 	if (ec->curr->wlen > ec->curr->wi) {
176 		if ((status & ACPI_EC_FLAG_IBF) == 0)
177 			acpi_ec_write_data(ec,
178 				ec->curr->wdata[ec->curr->wi++]);
179 		else
180 			goto err;
181 	} else if (ec->curr->rlen > ec->curr->ri) {
182 		if ((status & ACPI_EC_FLAG_OBF) == 1) {
183 			ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
184 			if (ec->curr->rlen == ec->curr->ri)
185 				ec->curr->done = true;
186 		} else
187 			goto err;
188 	} else if (ec->curr->wlen == ec->curr->wi &&
189 		   (status & ACPI_EC_FLAG_IBF) == 0)
190 		ec->curr->done = true;
191 	goto unlock;
192 err:
193 	/* false interrupt, state didn't change */
194 	if (in_interrupt())
195 		++ec->curr->irq_count;
196 unlock:
197 	spin_unlock_irqrestore(&ec->curr_lock, flags);
198 }
199 
200 static int acpi_ec_sync_query(struct acpi_ec *ec);
201 
202 static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
203 {
204 	if (state & ACPI_EC_FLAG_SCI) {
205 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
206 			return acpi_ec_sync_query(ec);
207 	}
208 	return 0;
209 }
210 
211 static int ec_poll(struct acpi_ec *ec)
212 {
213 	unsigned long flags;
214 	int repeat = 2; /* number of command restarts */
215 	while (repeat--) {
216 		unsigned long delay = jiffies +
217 			msecs_to_jiffies(ec_delay);
218 		do {
219 			/* don't sleep with disabled interrupts */
220 			if (EC_FLAGS_MSI || irqs_disabled()) {
221 				udelay(ACPI_EC_MSI_UDELAY);
222 				if (ec_transaction_done(ec))
223 					return 0;
224 			} else {
225 				if (wait_event_timeout(ec->wait,
226 						ec_transaction_done(ec),
227 						msecs_to_jiffies(1)))
228 					return 0;
229 			}
230 			advance_transaction(ec, acpi_ec_read_status(ec));
231 		} while (time_before(jiffies, delay));
232 		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
233 			break;
234 		pr_debug(PREFIX "controller reset, restart transaction\n");
235 		spin_lock_irqsave(&ec->curr_lock, flags);
236 		start_transaction(ec);
237 		spin_unlock_irqrestore(&ec->curr_lock, flags);
238 	}
239 	return -ETIME;
240 }
241 
242 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
243 					struct transaction *t)
244 {
245 	unsigned long tmp;
246 	int ret = 0;
247 	if (EC_FLAGS_MSI)
248 		udelay(ACPI_EC_MSI_UDELAY);
249 	/* start transaction */
250 	spin_lock_irqsave(&ec->curr_lock, tmp);
251 	/* following two actions should be kept atomic */
252 	ec->curr = t;
253 	start_transaction(ec);
254 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
255 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
256 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
257 	ret = ec_poll(ec);
258 	spin_lock_irqsave(&ec->curr_lock, tmp);
259 	ec->curr = NULL;
260 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
261 	return ret;
262 }
263 
264 static int ec_check_ibf0(struct acpi_ec *ec)
265 {
266 	u8 status = acpi_ec_read_status(ec);
267 	return (status & ACPI_EC_FLAG_IBF) == 0;
268 }
269 
270 static int ec_wait_ibf0(struct acpi_ec *ec)
271 {
272 	unsigned long delay = jiffies + msecs_to_jiffies(ec_delay);
273 	/* interrupt wait manually if GPE mode is not active */
274 	while (time_before(jiffies, delay))
275 		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
276 					msecs_to_jiffies(1)))
277 			return 0;
278 	return -ETIME;
279 }
280 
281 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
282 {
283 	int status;
284 	u32 glk;
285 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
286 		return -EINVAL;
287 	if (t->rdata)
288 		memset(t->rdata, 0, t->rlen);
289 	mutex_lock(&ec->lock);
290 	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
291 		status = -EINVAL;
292 		goto unlock;
293 	}
294 	if (ec->global_lock) {
295 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
296 		if (ACPI_FAILURE(status)) {
297 			status = -ENODEV;
298 			goto unlock;
299 		}
300 	}
301 	if (ec_wait_ibf0(ec)) {
302 		pr_err(PREFIX "input buffer is not empty, "
303 				"aborting transaction\n");
304 		status = -ETIME;
305 		goto end;
306 	}
307 	pr_debug(PREFIX "transaction start\n");
308 	/* disable GPE during transaction if storm is detected */
309 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
310 		/* It has to be disabled, so that it doesn't trigger. */
311 		acpi_disable_gpe(NULL, ec->gpe);
312 	}
313 
314 	status = acpi_ec_transaction_unlocked(ec, t);
315 
316 	/* check if we received SCI during transaction */
317 	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
318 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
319 		msleep(1);
320 		/* It is safe to enable the GPE outside of the transaction. */
321 		acpi_enable_gpe(NULL, ec->gpe);
322 	} else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {
323 		pr_info(PREFIX "GPE storm detected, "
324 			"transactions will use polling mode\n");
325 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
326 	}
327 	pr_debug(PREFIX "transaction end\n");
328 end:
329 	if (ec->global_lock)
330 		acpi_release_global_lock(glk);
331 unlock:
332 	mutex_unlock(&ec->lock);
333 	return status;
334 }
335 
336 static int acpi_ec_burst_enable(struct acpi_ec *ec)
337 {
338 	u8 d;
339 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
340 				.wdata = NULL, .rdata = &d,
341 				.wlen = 0, .rlen = 1};
342 
343 	return acpi_ec_transaction(ec, &t);
344 }
345 
346 static int acpi_ec_burst_disable(struct acpi_ec *ec)
347 {
348 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
349 				.wdata = NULL, .rdata = NULL,
350 				.wlen = 0, .rlen = 0};
351 
352 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
353 				acpi_ec_transaction(ec, &t) : 0;
354 }
355 
356 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
357 {
358 	int result;
359 	u8 d;
360 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
361 				.wdata = &address, .rdata = &d,
362 				.wlen = 1, .rlen = 1};
363 
364 	result = acpi_ec_transaction(ec, &t);
365 	*data = d;
366 	return result;
367 }
368 
369 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
370 {
371 	u8 wdata[2] = { address, data };
372 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
373 				.wdata = wdata, .rdata = NULL,
374 				.wlen = 2, .rlen = 0};
375 
376 	return acpi_ec_transaction(ec, &t);
377 }
378 
379 /*
380  * Externally callable EC access functions. For now, assume 1 EC only
381  */
382 int ec_burst_enable(void)
383 {
384 	if (!first_ec)
385 		return -ENODEV;
386 	return acpi_ec_burst_enable(first_ec);
387 }
388 
389 EXPORT_SYMBOL(ec_burst_enable);
390 
391 int ec_burst_disable(void)
392 {
393 	if (!first_ec)
394 		return -ENODEV;
395 	return acpi_ec_burst_disable(first_ec);
396 }
397 
398 EXPORT_SYMBOL(ec_burst_disable);
399 
400 int ec_read(u8 addr, u8 * val)
401 {
402 	int err;
403 	u8 temp_data;
404 
405 	if (!first_ec)
406 		return -ENODEV;
407 
408 	err = acpi_ec_read(first_ec, addr, &temp_data);
409 
410 	if (!err) {
411 		*val = temp_data;
412 		return 0;
413 	} else
414 		return err;
415 }
416 
417 EXPORT_SYMBOL(ec_read);
418 
419 int ec_write(u8 addr, u8 val)
420 {
421 	int err;
422 
423 	if (!first_ec)
424 		return -ENODEV;
425 
426 	err = acpi_ec_write(first_ec, addr, val);
427 
428 	return err;
429 }
430 
431 EXPORT_SYMBOL(ec_write);
432 
433 int ec_transaction(u8 command,
434 		   const u8 * wdata, unsigned wdata_len,
435 		   u8 * rdata, unsigned rdata_len)
436 {
437 	struct transaction t = {.command = command,
438 				.wdata = wdata, .rdata = rdata,
439 				.wlen = wdata_len, .rlen = rdata_len};
440 	if (!first_ec)
441 		return -ENODEV;
442 
443 	return acpi_ec_transaction(first_ec, &t);
444 }
445 
446 EXPORT_SYMBOL(ec_transaction);
447 
448 void acpi_ec_block_transactions(void)
449 {
450 	struct acpi_ec *ec = first_ec;
451 
452 	if (!ec)
453 		return;
454 
455 	mutex_lock(&ec->lock);
456 	/* Prevent transactions from being carried out */
457 	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
458 	mutex_unlock(&ec->lock);
459 }
460 
461 void acpi_ec_unblock_transactions(void)
462 {
463 	struct acpi_ec *ec = first_ec;
464 
465 	if (!ec)
466 		return;
467 
468 	mutex_lock(&ec->lock);
469 	/* Allow transactions to be carried out again */
470 	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
471 	mutex_unlock(&ec->lock);
472 }
473 
474 void acpi_ec_unblock_transactions_early(void)
475 {
476 	/*
477 	 * Allow transactions to happen again (this function is called from
478 	 * atomic context during wakeup, so we don't need to acquire the mutex).
479 	 */
480 	if (first_ec)
481 		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
482 }
483 
484 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
485 {
486 	int result;
487 	u8 d;
488 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
489 				.wdata = NULL, .rdata = &d,
490 				.wlen = 0, .rlen = 1};
491 	if (!ec || !data)
492 		return -EINVAL;
493 	/*
494 	 * Query the EC to find out which _Qxx method we need to evaluate.
495 	 * Note that successful completion of the query causes the ACPI_EC_SCI
496 	 * bit to be cleared (and thus clearing the interrupt source).
497 	 */
498 	result = acpi_ec_transaction_unlocked(ec, &t);
499 	if (result)
500 		return result;
501 	if (!d)
502 		return -ENODATA;
503 	*data = d;
504 	return 0;
505 }
506 
507 /* --------------------------------------------------------------------------
508                                 Event Management
509    -------------------------------------------------------------------------- */
510 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
511 			      acpi_handle handle, acpi_ec_query_func func,
512 			      void *data)
513 {
514 	struct acpi_ec_query_handler *handler =
515 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
516 	if (!handler)
517 		return -ENOMEM;
518 
519 	handler->query_bit = query_bit;
520 	handler->handle = handle;
521 	handler->func = func;
522 	handler->data = data;
523 	mutex_lock(&ec->lock);
524 	list_add(&handler->node, &ec->list);
525 	mutex_unlock(&ec->lock);
526 	return 0;
527 }
528 
529 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
530 
531 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
532 {
533 	struct acpi_ec_query_handler *handler, *tmp;
534 	mutex_lock(&ec->lock);
535 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
536 		if (query_bit == handler->query_bit) {
537 			list_del(&handler->node);
538 			kfree(handler);
539 		}
540 	}
541 	mutex_unlock(&ec->lock);
542 }
543 
544 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
545 
546 static void acpi_ec_run(void *cxt)
547 {
548 	struct acpi_ec_query_handler *handler = cxt;
549 	if (!handler)
550 		return;
551 	pr_debug(PREFIX "start query execution\n");
552 	if (handler->func)
553 		handler->func(handler->data);
554 	else if (handler->handle)
555 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
556 	pr_debug(PREFIX "stop query execution\n");
557 	kfree(handler);
558 }
559 
560 static int acpi_ec_sync_query(struct acpi_ec *ec)
561 {
562 	u8 value = 0;
563 	int status;
564 	struct acpi_ec_query_handler *handler, *copy;
565 	if ((status = acpi_ec_query_unlocked(ec, &value)))
566 		return status;
567 	list_for_each_entry(handler, &ec->list, node) {
568 		if (value == handler->query_bit) {
569 			/* have custom handler for this bit */
570 			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
571 			if (!copy)
572 				return -ENOMEM;
573 			memcpy(copy, handler, sizeof(*copy));
574 			pr_debug(PREFIX "push query execution (0x%2x) on queue\n", value);
575 			return acpi_os_execute((copy->func) ?
576 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
577 				acpi_ec_run, copy);
578 		}
579 	}
580 	return 0;
581 }
582 
583 static void acpi_ec_gpe_query(void *ec_cxt)
584 {
585 	struct acpi_ec *ec = ec_cxt;
586 	if (!ec)
587 		return;
588 	mutex_lock(&ec->lock);
589 	acpi_ec_sync_query(ec);
590 	mutex_unlock(&ec->lock);
591 }
592 
593 static int ec_check_sci(struct acpi_ec *ec, u8 state)
594 {
595 	if (state & ACPI_EC_FLAG_SCI) {
596 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
597 			pr_debug(PREFIX "push gpe query to the queue\n");
598 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
599 				acpi_ec_gpe_query, ec);
600 		}
601 	}
602 	return 0;
603 }
604 
605 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
606 	u32 gpe_number, void *data)
607 {
608 	struct acpi_ec *ec = data;
609 
610 	pr_debug(PREFIX "~~~> interrupt\n");
611 
612 	advance_transaction(ec, acpi_ec_read_status(ec));
613 	if (ec_transaction_done(ec) &&
614 	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
615 		wake_up(&ec->wait);
616 		ec_check_sci(ec, acpi_ec_read_status(ec));
617 	}
618 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
619 }
620 
621 /* --------------------------------------------------------------------------
622                              Address Space Management
623    -------------------------------------------------------------------------- */
624 
625 static acpi_status
626 acpi_ec_space_handler(u32 function, acpi_physical_address address,
627 		      u32 bits, u64 *value64,
628 		      void *handler_context, void *region_context)
629 {
630 	struct acpi_ec *ec = handler_context;
631 	int result = 0, i, bytes = bits / 8;
632 	u8 *value = (u8 *)value64;
633 
634 	if ((address > 0xFF) || !value || !handler_context)
635 		return AE_BAD_PARAMETER;
636 
637 	if (function != ACPI_READ && function != ACPI_WRITE)
638 		return AE_BAD_PARAMETER;
639 
640 	if (EC_FLAGS_MSI || bits > 8)
641 		acpi_ec_burst_enable(ec);
642 
643 	for (i = 0; i < bytes; ++i, ++address, ++value)
644 		result = (function == ACPI_READ) ?
645 			acpi_ec_read(ec, address, value) :
646 			acpi_ec_write(ec, address, *value);
647 
648 	if (EC_FLAGS_MSI || bits > 8)
649 		acpi_ec_burst_disable(ec);
650 
651 	switch (result) {
652 	case -EINVAL:
653 		return AE_BAD_PARAMETER;
654 		break;
655 	case -ENODEV:
656 		return AE_NOT_FOUND;
657 		break;
658 	case -ETIME:
659 		return AE_TIME;
660 		break;
661 	default:
662 		return AE_OK;
663 	}
664 }
665 
666 /* --------------------------------------------------------------------------
667                                Driver Interface
668    -------------------------------------------------------------------------- */
669 static acpi_status
670 ec_parse_io_ports(struct acpi_resource *resource, void *context);
671 
672 static struct acpi_ec *make_acpi_ec(void)
673 {
674 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
675 	if (!ec)
676 		return NULL;
677 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
678 	mutex_init(&ec->lock);
679 	init_waitqueue_head(&ec->wait);
680 	INIT_LIST_HEAD(&ec->list);
681 	spin_lock_init(&ec->curr_lock);
682 	return ec;
683 }
684 
685 static acpi_status
686 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
687 			       void *context, void **return_value)
688 {
689 	char node_name[5];
690 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
691 	struct acpi_ec *ec = context;
692 	int value = 0;
693 	acpi_status status;
694 
695 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
696 
697 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
698 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
699 	}
700 	return AE_OK;
701 }
702 
703 static acpi_status
704 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
705 {
706 	acpi_status status;
707 	unsigned long long tmp = 0;
708 
709 	struct acpi_ec *ec = context;
710 
711 	/* clear addr values, ec_parse_io_ports depend on it */
712 	ec->command_addr = ec->data_addr = 0;
713 
714 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
715 				     ec_parse_io_ports, ec);
716 	if (ACPI_FAILURE(status))
717 		return status;
718 
719 	/* Get GPE bit assignment (EC events). */
720 	/* TODO: Add support for _GPE returning a package */
721 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
722 	if (ACPI_FAILURE(status))
723 		return status;
724 	ec->gpe = tmp;
725 	/* Use the global lock for all EC transactions? */
726 	tmp = 0;
727 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
728 	ec->global_lock = tmp;
729 	ec->handle = handle;
730 	return AE_CTRL_TERMINATE;
731 }
732 
733 static int ec_install_handlers(struct acpi_ec *ec)
734 {
735 	acpi_status status;
736 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
737 		return 0;
738 	status = acpi_install_gpe_handler(NULL, ec->gpe,
739 				  ACPI_GPE_EDGE_TRIGGERED,
740 				  &acpi_ec_gpe_handler, ec);
741 	if (ACPI_FAILURE(status))
742 		return -ENODEV;
743 
744 	acpi_enable_gpe(NULL, ec->gpe);
745 	status = acpi_install_address_space_handler(ec->handle,
746 						    ACPI_ADR_SPACE_EC,
747 						    &acpi_ec_space_handler,
748 						    NULL, ec);
749 	if (ACPI_FAILURE(status)) {
750 		if (status == AE_NOT_FOUND) {
751 			/*
752 			 * Maybe OS fails in evaluating the _REG object.
753 			 * The AE_NOT_FOUND error will be ignored and OS
754 			 * continue to initialize EC.
755 			 */
756 			printk(KERN_ERR "Fail in evaluating the _REG object"
757 				" of EC device. Broken bios is suspected.\n");
758 		} else {
759 			acpi_remove_gpe_handler(NULL, ec->gpe,
760 				&acpi_ec_gpe_handler);
761 			acpi_disable_gpe(NULL, ec->gpe);
762 			return -ENODEV;
763 		}
764 	}
765 
766 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
767 	return 0;
768 }
769 
770 static void ec_remove_handlers(struct acpi_ec *ec)
771 {
772 	acpi_disable_gpe(NULL, ec->gpe);
773 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
774 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
775 		pr_err(PREFIX "failed to remove space handler\n");
776 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
777 				&acpi_ec_gpe_handler)))
778 		pr_err(PREFIX "failed to remove gpe handler\n");
779 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
780 }
781 
782 static int acpi_ec_add(struct acpi_device *device)
783 {
784 	struct acpi_ec *ec = NULL;
785 	int ret;
786 
787 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
788 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
789 
790 	/* Check for boot EC */
791 	if (boot_ec &&
792 	    (boot_ec->handle == device->handle ||
793 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
794 		ec = boot_ec;
795 		boot_ec = NULL;
796 	} else {
797 		ec = make_acpi_ec();
798 		if (!ec)
799 			return -ENOMEM;
800 	}
801 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
802 		AE_CTRL_TERMINATE) {
803 			kfree(ec);
804 			return -EINVAL;
805 	}
806 
807 	/* Find and register all query methods */
808 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
809 			    acpi_ec_register_query_methods, NULL, ec, NULL);
810 
811 	if (!first_ec)
812 		first_ec = ec;
813 	device->driver_data = ec;
814 
815 	WARN(!request_region(ec->data_addr, 1, "EC data"),
816 	     "Could not request EC data io port 0x%lx", ec->data_addr);
817 	WARN(!request_region(ec->command_addr, 1, "EC cmd"),
818 	     "Could not request EC cmd io port 0x%lx", ec->command_addr);
819 
820 	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
821 			  ec->gpe, ec->command_addr, ec->data_addr);
822 
823 	ret = ec_install_handlers(ec);
824 
825 	/* EC is fully operational, allow queries */
826 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
827 	return ret;
828 }
829 
830 static int acpi_ec_remove(struct acpi_device *device, int type)
831 {
832 	struct acpi_ec *ec;
833 	struct acpi_ec_query_handler *handler, *tmp;
834 
835 	if (!device)
836 		return -EINVAL;
837 
838 	ec = acpi_driver_data(device);
839 	ec_remove_handlers(ec);
840 	mutex_lock(&ec->lock);
841 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
842 		list_del(&handler->node);
843 		kfree(handler);
844 	}
845 	mutex_unlock(&ec->lock);
846 	release_region(ec->data_addr, 1);
847 	release_region(ec->command_addr, 1);
848 	device->driver_data = NULL;
849 	if (ec == first_ec)
850 		first_ec = NULL;
851 	kfree(ec);
852 	return 0;
853 }
854 
855 static acpi_status
856 ec_parse_io_ports(struct acpi_resource *resource, void *context)
857 {
858 	struct acpi_ec *ec = context;
859 
860 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
861 		return AE_OK;
862 
863 	/*
864 	 * The first address region returned is the data port, and
865 	 * the second address region returned is the status/command
866 	 * port.
867 	 */
868 	if (ec->data_addr == 0)
869 		ec->data_addr = resource->data.io.minimum;
870 	else if (ec->command_addr == 0)
871 		ec->command_addr = resource->data.io.minimum;
872 	else
873 		return AE_CTRL_TERMINATE;
874 
875 	return AE_OK;
876 }
877 
878 int __init acpi_boot_ec_enable(void)
879 {
880 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
881 		return 0;
882 	if (!ec_install_handlers(boot_ec)) {
883 		first_ec = boot_ec;
884 		return 0;
885 	}
886 	return -EFAULT;
887 }
888 
889 static const struct acpi_device_id ec_device_ids[] = {
890 	{"PNP0C09", 0},
891 	{"", 0},
892 };
893 
894 /* Some BIOS do not survive early DSDT scan, skip it */
895 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
896 {
897 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
898 	return 0;
899 }
900 
901 /* ASUStek often supplies us with broken ECDT, validate it */
902 static int ec_validate_ecdt(const struct dmi_system_id *id)
903 {
904 	EC_FLAGS_VALIDATE_ECDT = 1;
905 	return 0;
906 }
907 
908 /* MSI EC needs special treatment, enable it */
909 static int ec_flag_msi(const struct dmi_system_id *id)
910 {
911 	printk(KERN_DEBUG PREFIX "Detected MSI hardware, enabling workarounds.\n");
912 	EC_FLAGS_MSI = 1;
913 	EC_FLAGS_VALIDATE_ECDT = 1;
914 	return 0;
915 }
916 
917 static struct dmi_system_id __initdata ec_dmi_table[] = {
918 	{
919 	ec_skip_dsdt_scan, "Compal JFL92", {
920 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
921 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
922 	{
923 	ec_flag_msi, "MSI hardware", {
924 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
925 	{
926 	ec_flag_msi, "MSI hardware", {
927 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
928 	{
929 	ec_flag_msi, "MSI hardware", {
930 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
931 	{
932 	ec_flag_msi, "MSI hardware", {
933 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
934 	{
935 	ec_flag_msi, "Quanta hardware", {
936 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
937 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
938 	{
939 	ec_flag_msi, "Quanta hardware", {
940 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
941 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
942 	{
943 	ec_validate_ecdt, "ASUS hardware", {
944 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
945 	{
946 	ec_validate_ecdt, "ASUS hardware", {
947 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
948 	{},
949 };
950 
951 
952 int __init acpi_ec_ecdt_probe(void)
953 {
954 	acpi_status status;
955 	struct acpi_ec *saved_ec = NULL;
956 	struct acpi_table_ecdt *ecdt_ptr;
957 
958 	boot_ec = make_acpi_ec();
959 	if (!boot_ec)
960 		return -ENOMEM;
961 	/*
962 	 * Generate a boot ec context
963 	 */
964 	dmi_check_system(ec_dmi_table);
965 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
966 				(struct acpi_table_header **)&ecdt_ptr);
967 	if (ACPI_SUCCESS(status)) {
968 		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
969 		boot_ec->command_addr = ecdt_ptr->control.address;
970 		boot_ec->data_addr = ecdt_ptr->data.address;
971 		boot_ec->gpe = ecdt_ptr->gpe;
972 		boot_ec->handle = ACPI_ROOT_OBJECT;
973 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
974 		/* Don't trust ECDT, which comes from ASUSTek */
975 		if (!EC_FLAGS_VALIDATE_ECDT)
976 			goto install;
977 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
978 		if (!saved_ec)
979 			return -ENOMEM;
980 	/* fall through */
981 	}
982 
983 	if (EC_FLAGS_SKIP_DSDT_SCAN)
984 		return -ENODEV;
985 
986 	/* This workaround is needed only on some broken machines,
987 	 * which require early EC, but fail to provide ECDT */
988 	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
989 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
990 					boot_ec, NULL);
991 	/* Check that acpi_get_devices actually find something */
992 	if (ACPI_FAILURE(status) || !boot_ec->handle)
993 		goto error;
994 	if (saved_ec) {
995 		/* try to find good ECDT from ASUSTek */
996 		if (saved_ec->command_addr != boot_ec->command_addr ||
997 		    saved_ec->data_addr != boot_ec->data_addr ||
998 		    saved_ec->gpe != boot_ec->gpe ||
999 		    saved_ec->handle != boot_ec->handle)
1000 			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
1001 			"ECDT tables, which are very hard to workaround. "
1002 			"Trying to use DSDT EC info instead. Please send "
1003 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1004 		kfree(saved_ec);
1005 		saved_ec = NULL;
1006 	} else {
1007 		/* We really need to limit this workaround, the only ASUS,
1008 		* which needs it, has fake EC._INI method, so use it as flag.
1009 		* Keep boot_ec struct as it will be needed soon.
1010 		*/
1011 		acpi_handle dummy;
1012 		if (!dmi_name_in_vendors("ASUS") ||
1013 		    ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI",
1014 							&dummy)))
1015 			return -ENODEV;
1016 	}
1017 install:
1018 	if (!ec_install_handlers(boot_ec)) {
1019 		first_ec = boot_ec;
1020 		return 0;
1021 	}
1022 error:
1023 	kfree(boot_ec);
1024 	boot_ec = NULL;
1025 	return -ENODEV;
1026 }
1027 
1028 static struct acpi_driver acpi_ec_driver = {
1029 	.name = "ec",
1030 	.class = ACPI_EC_CLASS,
1031 	.ids = ec_device_ids,
1032 	.ops = {
1033 		.add = acpi_ec_add,
1034 		.remove = acpi_ec_remove,
1035 		},
1036 };
1037 
1038 int __init acpi_ec_init(void)
1039 {
1040 	int result = 0;
1041 
1042 	/* Now register the driver for the EC */
1043 	result = acpi_bus_register_driver(&acpi_ec_driver);
1044 	if (result < 0)
1045 		return -ENODEV;
1046 
1047 	return result;
1048 }
1049 
1050 /* EC driver currently not unloadable */
1051 #if 0
1052 static void __exit acpi_ec_exit(void)
1053 {
1054 
1055 	acpi_bus_unregister_driver(&acpi_ec_driver);
1056 	return;
1057 }
1058 #endif	/* 0 */
1059