xref: /openbmc/linux/drivers/acpi/ec.c (revision 36bccb11)
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, u8 *data);
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, NULL);
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 /*
447  * Process _Q events that might have accumulated in the EC.
448  * Run with locked ec mutex.
449  */
450 static void acpi_ec_clear(struct acpi_ec *ec)
451 {
452 	int i, status;
453 	u8 value = 0;
454 
455 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
456 		status = acpi_ec_sync_query(ec, &value);
457 		if (status || !value)
458 			break;
459 	}
460 
461 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
462 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
463 	else
464 		pr_info("%d stale EC events cleared\n", i);
465 }
466 
467 void acpi_ec_block_transactions(void)
468 {
469 	struct acpi_ec *ec = first_ec;
470 
471 	if (!ec)
472 		return;
473 
474 	mutex_lock(&ec->mutex);
475 	/* Prevent transactions from being carried out */
476 	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
477 	mutex_unlock(&ec->mutex);
478 }
479 
480 void acpi_ec_unblock_transactions(void)
481 {
482 	struct acpi_ec *ec = first_ec;
483 
484 	if (!ec)
485 		return;
486 
487 	mutex_lock(&ec->mutex);
488 	/* Allow transactions to be carried out again */
489 	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
490 
491 	if (EC_FLAGS_CLEAR_ON_RESUME)
492 		acpi_ec_clear(ec);
493 
494 	mutex_unlock(&ec->mutex);
495 }
496 
497 void acpi_ec_unblock_transactions_early(void)
498 {
499 	/*
500 	 * Allow transactions to happen again (this function is called from
501 	 * atomic context during wakeup, so we don't need to acquire the mutex).
502 	 */
503 	if (first_ec)
504 		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
505 }
506 
507 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
508 {
509 	int result;
510 	u8 d;
511 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
512 				.wdata = NULL, .rdata = &d,
513 				.wlen = 0, .rlen = 1};
514 	if (!ec || !data)
515 		return -EINVAL;
516 	/*
517 	 * Query the EC to find out which _Qxx method we need to evaluate.
518 	 * Note that successful completion of the query causes the ACPI_EC_SCI
519 	 * bit to be cleared (and thus clearing the interrupt source).
520 	 */
521 	result = acpi_ec_transaction_unlocked(ec, &t);
522 	if (result)
523 		return result;
524 	if (!d)
525 		return -ENODATA;
526 	*data = d;
527 	return 0;
528 }
529 
530 /* --------------------------------------------------------------------------
531                                 Event Management
532    -------------------------------------------------------------------------- */
533 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
534 			      acpi_handle handle, acpi_ec_query_func func,
535 			      void *data)
536 {
537 	struct acpi_ec_query_handler *handler =
538 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
539 	if (!handler)
540 		return -ENOMEM;
541 
542 	handler->query_bit = query_bit;
543 	handler->handle = handle;
544 	handler->func = func;
545 	handler->data = data;
546 	mutex_lock(&ec->mutex);
547 	list_add(&handler->node, &ec->list);
548 	mutex_unlock(&ec->mutex);
549 	return 0;
550 }
551 
552 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
553 
554 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
555 {
556 	struct acpi_ec_query_handler *handler, *tmp;
557 	mutex_lock(&ec->mutex);
558 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
559 		if (query_bit == handler->query_bit) {
560 			list_del(&handler->node);
561 			kfree(handler);
562 		}
563 	}
564 	mutex_unlock(&ec->mutex);
565 }
566 
567 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
568 
569 static void acpi_ec_run(void *cxt)
570 {
571 	struct acpi_ec_query_handler *handler = cxt;
572 	if (!handler)
573 		return;
574 	pr_debug("start query execution\n");
575 	if (handler->func)
576 		handler->func(handler->data);
577 	else if (handler->handle)
578 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
579 	pr_debug("stop query execution\n");
580 	kfree(handler);
581 }
582 
583 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
584 {
585 	u8 value = 0;
586 	int status;
587 	struct acpi_ec_query_handler *handler, *copy;
588 
589 	status = acpi_ec_query_unlocked(ec, &value);
590 	if (data)
591 		*data = value;
592 	if (status)
593 		return status;
594 
595 	list_for_each_entry(handler, &ec->list, node) {
596 		if (value == handler->query_bit) {
597 			/* have custom handler for this bit */
598 			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
599 			if (!copy)
600 				return -ENOMEM;
601 			memcpy(copy, handler, sizeof(*copy));
602 			pr_debug("push query execution (0x%2x) on queue\n",
603 				value);
604 			return acpi_os_execute((copy->func) ?
605 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
606 				acpi_ec_run, copy);
607 		}
608 	}
609 	return 0;
610 }
611 
612 static void acpi_ec_gpe_query(void *ec_cxt)
613 {
614 	struct acpi_ec *ec = ec_cxt;
615 	if (!ec)
616 		return;
617 	mutex_lock(&ec->mutex);
618 	acpi_ec_sync_query(ec, NULL);
619 	mutex_unlock(&ec->mutex);
620 }
621 
622 static int ec_check_sci(struct acpi_ec *ec, u8 state)
623 {
624 	if (state & ACPI_EC_FLAG_SCI) {
625 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
626 			pr_debug("push gpe query to the queue\n");
627 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
628 				acpi_ec_gpe_query, ec);
629 		}
630 	}
631 	return 0;
632 }
633 
634 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
635 	u32 gpe_number, void *data)
636 {
637 	struct acpi_ec *ec = data;
638 	u8 status = acpi_ec_read_status(ec);
639 
640 	pr_debug("~~~> interrupt, status:0x%02x\n", status);
641 
642 	advance_transaction(ec, status);
643 	if (ec_transaction_done(ec) &&
644 	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
645 		wake_up(&ec->wait);
646 		ec_check_sci(ec, acpi_ec_read_status(ec));
647 	}
648 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
649 }
650 
651 /* --------------------------------------------------------------------------
652                              Address Space Management
653    -------------------------------------------------------------------------- */
654 
655 static acpi_status
656 acpi_ec_space_handler(u32 function, acpi_physical_address address,
657 		      u32 bits, u64 *value64,
658 		      void *handler_context, void *region_context)
659 {
660 	struct acpi_ec *ec = handler_context;
661 	int result = 0, i, bytes = bits / 8;
662 	u8 *value = (u8 *)value64;
663 
664 	if ((address > 0xFF) || !value || !handler_context)
665 		return AE_BAD_PARAMETER;
666 
667 	if (function != ACPI_READ && function != ACPI_WRITE)
668 		return AE_BAD_PARAMETER;
669 
670 	if (EC_FLAGS_MSI || bits > 8)
671 		acpi_ec_burst_enable(ec);
672 
673 	for (i = 0; i < bytes; ++i, ++address, ++value)
674 		result = (function == ACPI_READ) ?
675 			acpi_ec_read(ec, address, value) :
676 			acpi_ec_write(ec, address, *value);
677 
678 	if (EC_FLAGS_MSI || bits > 8)
679 		acpi_ec_burst_disable(ec);
680 
681 	switch (result) {
682 	case -EINVAL:
683 		return AE_BAD_PARAMETER;
684 		break;
685 	case -ENODEV:
686 		return AE_NOT_FOUND;
687 		break;
688 	case -ETIME:
689 		return AE_TIME;
690 		break;
691 	default:
692 		return AE_OK;
693 	}
694 }
695 
696 /* --------------------------------------------------------------------------
697                                Driver Interface
698    -------------------------------------------------------------------------- */
699 static acpi_status
700 ec_parse_io_ports(struct acpi_resource *resource, void *context);
701 
702 static struct acpi_ec *make_acpi_ec(void)
703 {
704 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
705 	if (!ec)
706 		return NULL;
707 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
708 	mutex_init(&ec->mutex);
709 	init_waitqueue_head(&ec->wait);
710 	INIT_LIST_HEAD(&ec->list);
711 	spin_lock_init(&ec->lock);
712 	return ec;
713 }
714 
715 static acpi_status
716 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
717 			       void *context, void **return_value)
718 {
719 	char node_name[5];
720 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
721 	struct acpi_ec *ec = context;
722 	int value = 0;
723 	acpi_status status;
724 
725 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
726 
727 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
728 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
729 	}
730 	return AE_OK;
731 }
732 
733 static acpi_status
734 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
735 {
736 	acpi_status status;
737 	unsigned long long tmp = 0;
738 
739 	struct acpi_ec *ec = context;
740 
741 	/* clear addr values, ec_parse_io_ports depend on it */
742 	ec->command_addr = ec->data_addr = 0;
743 
744 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
745 				     ec_parse_io_ports, ec);
746 	if (ACPI_FAILURE(status))
747 		return status;
748 
749 	/* Get GPE bit assignment (EC events). */
750 	/* TODO: Add support for _GPE returning a package */
751 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
752 	if (ACPI_FAILURE(status))
753 		return status;
754 	ec->gpe = tmp;
755 	/* Use the global lock for all EC transactions? */
756 	tmp = 0;
757 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
758 	ec->global_lock = tmp;
759 	ec->handle = handle;
760 	return AE_CTRL_TERMINATE;
761 }
762 
763 static int ec_install_handlers(struct acpi_ec *ec)
764 {
765 	acpi_status status;
766 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
767 		return 0;
768 	status = acpi_install_gpe_handler(NULL, ec->gpe,
769 				  ACPI_GPE_EDGE_TRIGGERED,
770 				  &acpi_ec_gpe_handler, ec);
771 	if (ACPI_FAILURE(status))
772 		return -ENODEV;
773 
774 	acpi_enable_gpe(NULL, ec->gpe);
775 	status = acpi_install_address_space_handler(ec->handle,
776 						    ACPI_ADR_SPACE_EC,
777 						    &acpi_ec_space_handler,
778 						    NULL, ec);
779 	if (ACPI_FAILURE(status)) {
780 		if (status == AE_NOT_FOUND) {
781 			/*
782 			 * Maybe OS fails in evaluating the _REG object.
783 			 * The AE_NOT_FOUND error will be ignored and OS
784 			 * continue to initialize EC.
785 			 */
786 			pr_err("Fail in evaluating the _REG object"
787 				" of EC device. Broken bios is suspected.\n");
788 		} else {
789 			acpi_disable_gpe(NULL, ec->gpe);
790 			acpi_remove_gpe_handler(NULL, ec->gpe,
791 				&acpi_ec_gpe_handler);
792 			return -ENODEV;
793 		}
794 	}
795 
796 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
797 	return 0;
798 }
799 
800 static void ec_remove_handlers(struct acpi_ec *ec)
801 {
802 	acpi_disable_gpe(NULL, ec->gpe);
803 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
804 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
805 		pr_err("failed to remove space handler\n");
806 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
807 				&acpi_ec_gpe_handler)))
808 		pr_err("failed to remove gpe handler\n");
809 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
810 }
811 
812 static int acpi_ec_add(struct acpi_device *device)
813 {
814 	struct acpi_ec *ec = NULL;
815 	int ret;
816 
817 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
818 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
819 
820 	/* Check for boot EC */
821 	if (boot_ec &&
822 	    (boot_ec->handle == device->handle ||
823 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
824 		ec = boot_ec;
825 		boot_ec = NULL;
826 	} else {
827 		ec = make_acpi_ec();
828 		if (!ec)
829 			return -ENOMEM;
830 	}
831 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
832 		AE_CTRL_TERMINATE) {
833 			kfree(ec);
834 			return -EINVAL;
835 	}
836 
837 	/* Find and register all query methods */
838 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
839 			    acpi_ec_register_query_methods, NULL, ec, NULL);
840 
841 	if (!first_ec)
842 		first_ec = ec;
843 	device->driver_data = ec;
844 
845 	ret = !!request_region(ec->data_addr, 1, "EC data");
846 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
847 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
848 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
849 
850 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
851 			  ec->gpe, ec->command_addr, ec->data_addr);
852 
853 	ret = ec_install_handlers(ec);
854 
855 	/* EC is fully operational, allow queries */
856 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
857 
858 	/* Clear stale _Q events if hardware might require that */
859 	if (EC_FLAGS_CLEAR_ON_RESUME) {
860 		mutex_lock(&ec->mutex);
861 		acpi_ec_clear(ec);
862 		mutex_unlock(&ec->mutex);
863 	}
864 	return ret;
865 }
866 
867 static int acpi_ec_remove(struct acpi_device *device)
868 {
869 	struct acpi_ec *ec;
870 	struct acpi_ec_query_handler *handler, *tmp;
871 
872 	if (!device)
873 		return -EINVAL;
874 
875 	ec = acpi_driver_data(device);
876 	ec_remove_handlers(ec);
877 	mutex_lock(&ec->mutex);
878 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
879 		list_del(&handler->node);
880 		kfree(handler);
881 	}
882 	mutex_unlock(&ec->mutex);
883 	release_region(ec->data_addr, 1);
884 	release_region(ec->command_addr, 1);
885 	device->driver_data = NULL;
886 	if (ec == first_ec)
887 		first_ec = NULL;
888 	kfree(ec);
889 	return 0;
890 }
891 
892 static acpi_status
893 ec_parse_io_ports(struct acpi_resource *resource, void *context)
894 {
895 	struct acpi_ec *ec = context;
896 
897 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
898 		return AE_OK;
899 
900 	/*
901 	 * The first address region returned is the data port, and
902 	 * the second address region returned is the status/command
903 	 * port.
904 	 */
905 	if (ec->data_addr == 0)
906 		ec->data_addr = resource->data.io.minimum;
907 	else if (ec->command_addr == 0)
908 		ec->command_addr = resource->data.io.minimum;
909 	else
910 		return AE_CTRL_TERMINATE;
911 
912 	return AE_OK;
913 }
914 
915 int __init acpi_boot_ec_enable(void)
916 {
917 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
918 		return 0;
919 	if (!ec_install_handlers(boot_ec)) {
920 		first_ec = boot_ec;
921 		return 0;
922 	}
923 	return -EFAULT;
924 }
925 
926 static const struct acpi_device_id ec_device_ids[] = {
927 	{"PNP0C09", 0},
928 	{"", 0},
929 };
930 
931 /* Some BIOS do not survive early DSDT scan, skip it */
932 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
933 {
934 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
935 	return 0;
936 }
937 
938 /* ASUStek often supplies us with broken ECDT, validate it */
939 static int ec_validate_ecdt(const struct dmi_system_id *id)
940 {
941 	EC_FLAGS_VALIDATE_ECDT = 1;
942 	return 0;
943 }
944 
945 /* MSI EC needs special treatment, enable it */
946 static int ec_flag_msi(const struct dmi_system_id *id)
947 {
948 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
949 	EC_FLAGS_MSI = 1;
950 	EC_FLAGS_VALIDATE_ECDT = 1;
951 	return 0;
952 }
953 
954 /*
955  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
956  * the GPE storm threshold back to 20
957  */
958 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
959 {
960 	pr_debug("Setting the EC GPE storm threshold to 20\n");
961 	ec_storm_threshold  = 20;
962 	return 0;
963 }
964 
965 /*
966  * On some hardware it is necessary to clear events accumulated by the EC during
967  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
968  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
969  *
970  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
971  *
972  * Ideally, the EC should also be instructed NOT to accumulate events during
973  * sleep (which Windows seems to do somehow), but the interface to control this
974  * behaviour is not known at this time.
975  *
976  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
977  * however it is very likely that other Samsung models are affected.
978  *
979  * On systems which don't accumulate _Q events during sleep, this extra check
980  * should be harmless.
981  */
982 static int ec_clear_on_resume(const struct dmi_system_id *id)
983 {
984 	pr_debug("Detected system needing EC poll on resume.\n");
985 	EC_FLAGS_CLEAR_ON_RESUME = 1;
986 	return 0;
987 }
988 
989 static struct dmi_system_id ec_dmi_table[] __initdata = {
990 	{
991 	ec_skip_dsdt_scan, "Compal JFL92", {
992 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
993 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
994 	{
995 	ec_flag_msi, "MSI hardware", {
996 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
997 	{
998 	ec_flag_msi, "MSI hardware", {
999 	DMI_MATCH(DMI_SYS_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, "MSI hardware", {
1005 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1006 	{
1007 	ec_flag_msi, "Quanta hardware", {
1008 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1009 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1010 	{
1011 	ec_flag_msi, "Quanta hardware", {
1012 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1013 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1014 	{
1015 	ec_validate_ecdt, "ASUS hardware", {
1016 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1017 	{
1018 	ec_validate_ecdt, "ASUS hardware", {
1019 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1020 	{
1021 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1022 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1023 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1024 	{
1025 	ec_skip_dsdt_scan, "HP Folio 13", {
1026 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1027 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1028 	{
1029 	ec_validate_ecdt, "ASUS hardware", {
1030 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1031 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1032 	{
1033 	ec_clear_on_resume, "Samsung hardware", {
1034 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1035 	{},
1036 };
1037 
1038 int __init acpi_ec_ecdt_probe(void)
1039 {
1040 	acpi_status status;
1041 	struct acpi_ec *saved_ec = NULL;
1042 	struct acpi_table_ecdt *ecdt_ptr;
1043 
1044 	boot_ec = make_acpi_ec();
1045 	if (!boot_ec)
1046 		return -ENOMEM;
1047 	/*
1048 	 * Generate a boot ec context
1049 	 */
1050 	dmi_check_system(ec_dmi_table);
1051 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1052 				(struct acpi_table_header **)&ecdt_ptr);
1053 	if (ACPI_SUCCESS(status)) {
1054 		pr_info("EC description table is found, configuring boot EC\n");
1055 		boot_ec->command_addr = ecdt_ptr->control.address;
1056 		boot_ec->data_addr = ecdt_ptr->data.address;
1057 		boot_ec->gpe = ecdt_ptr->gpe;
1058 		boot_ec->handle = ACPI_ROOT_OBJECT;
1059 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
1060 		/* Don't trust ECDT, which comes from ASUSTek */
1061 		if (!EC_FLAGS_VALIDATE_ECDT)
1062 			goto install;
1063 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1064 		if (!saved_ec)
1065 			return -ENOMEM;
1066 	/* fall through */
1067 	}
1068 
1069 	if (EC_FLAGS_SKIP_DSDT_SCAN)
1070 		return -ENODEV;
1071 
1072 	/* This workaround is needed only on some broken machines,
1073 	 * which require early EC, but fail to provide ECDT */
1074 	pr_debug("Look up EC in DSDT\n");
1075 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1076 					boot_ec, NULL);
1077 	/* Check that acpi_get_devices actually find something */
1078 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1079 		goto error;
1080 	if (saved_ec) {
1081 		/* try to find good ECDT from ASUSTek */
1082 		if (saved_ec->command_addr != boot_ec->command_addr ||
1083 		    saved_ec->data_addr != boot_ec->data_addr ||
1084 		    saved_ec->gpe != boot_ec->gpe ||
1085 		    saved_ec->handle != boot_ec->handle)
1086 			pr_info("ASUSTek keeps feeding us with broken "
1087 			"ECDT tables, which are very hard to workaround. "
1088 			"Trying to use DSDT EC info instead. Please send "
1089 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1090 		kfree(saved_ec);
1091 		saved_ec = NULL;
1092 	} else {
1093 		/* We really need to limit this workaround, the only ASUS,
1094 		* which needs it, has fake EC._INI method, so use it as flag.
1095 		* Keep boot_ec struct as it will be needed soon.
1096 		*/
1097 		if (!dmi_name_in_vendors("ASUS") ||
1098 		    !acpi_has_method(boot_ec->handle, "_INI"))
1099 			return -ENODEV;
1100 	}
1101 install:
1102 	if (!ec_install_handlers(boot_ec)) {
1103 		first_ec = boot_ec;
1104 		return 0;
1105 	}
1106 error:
1107 	kfree(boot_ec);
1108 	boot_ec = NULL;
1109 	return -ENODEV;
1110 }
1111 
1112 static struct acpi_driver acpi_ec_driver = {
1113 	.name = "ec",
1114 	.class = ACPI_EC_CLASS,
1115 	.ids = ec_device_ids,
1116 	.ops = {
1117 		.add = acpi_ec_add,
1118 		.remove = acpi_ec_remove,
1119 		},
1120 };
1121 
1122 int __init acpi_ec_init(void)
1123 {
1124 	int result = 0;
1125 
1126 	/* Now register the driver for the EC */
1127 	result = acpi_bus_register_driver(&acpi_ec_driver);
1128 	if (result < 0)
1129 		return -ENODEV;
1130 
1131 	return result;
1132 }
1133 
1134 /* EC driver currently not unloadable */
1135 #if 0
1136 static void __exit acpi_ec_exit(void)
1137 {
1138 
1139 	acpi_bus_unregister_driver(&acpi_ec_driver);
1140 	return;
1141 }
1142 #endif	/* 0 */
1143