xref: /openbmc/linux/drivers/acpi/ec.c (revision 62e7ca52)
1 /*
2  *  ec.c - ACPI Embedded Controller Driver (v2.2)
3  *
4  *  Copyright (C) 2001-2014 Intel Corporation
5  *    Author: 2014       Lv Zheng <lv.zheng@intel.com>
6  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
7  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
8  *            2004       Luming Yu <luming.yu@intel.com>
9  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
10  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
11  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
12  *
13  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
14  *
15  *  This program is free software; you can redistribute it and/or modify
16  *  it under the terms of the GNU General Public License as published by
17  *  the Free Software Foundation; either version 2 of the License, or (at
18  *  your option) any later version.
19  *
20  *  This program is distributed in the hope that it will be useful, but
21  *  WITHOUT ANY WARRANTY; without even the implied warranty of
22  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23  *  General Public License for more details.
24  *
25  *  You should have received a copy of the GNU General Public License along
26  *  with this program; if not, write to the Free Software Foundation, Inc.,
27  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
28  *
29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
30  */
31 
32 /* Uncomment next line to get verbose printout */
33 /* #define DEBUG */
34 #define pr_fmt(fmt) "ACPI : EC: " fmt
35 
36 #include <linux/kernel.h>
37 #include <linux/module.h>
38 #include <linux/init.h>
39 #include <linux/types.h>
40 #include <linux/delay.h>
41 #include <linux/interrupt.h>
42 #include <linux/list.h>
43 #include <linux/spinlock.h>
44 #include <linux/slab.h>
45 #include <linux/acpi.h>
46 #include <linux/dmi.h>
47 #include <asm/io.h>
48 
49 #include "internal.h"
50 
51 #define ACPI_EC_CLASS			"embedded_controller"
52 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
53 #define ACPI_EC_FILE_INFO		"info"
54 
55 /* EC status register */
56 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
57 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
58 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
59 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
60 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
61 
62 /* EC commands */
63 enum ec_command {
64 	ACPI_EC_COMMAND_READ = 0x80,
65 	ACPI_EC_COMMAND_WRITE = 0x81,
66 	ACPI_EC_BURST_ENABLE = 0x82,
67 	ACPI_EC_BURST_DISABLE = 0x83,
68 	ACPI_EC_COMMAND_QUERY = 0x84,
69 };
70 
71 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
72 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
73 #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
74 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
75 					 * when trying to clear the EC */
76 
77 enum {
78 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
79 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
80 	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
81 					 * OpReg are installed */
82 	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
83 };
84 
85 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
86 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
87 
88 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
89 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
90 module_param(ec_delay, uint, 0644);
91 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
92 
93 /*
94  * If the number of false interrupts per one transaction exceeds
95  * this threshold, will think there is a GPE storm happened and
96  * will disable the GPE for normal transaction.
97  */
98 static unsigned int ec_storm_threshold  __read_mostly = 8;
99 module_param(ec_storm_threshold, uint, 0644);
100 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
101 
102 struct acpi_ec_query_handler {
103 	struct list_head node;
104 	acpi_ec_query_func func;
105 	acpi_handle handle;
106 	void *data;
107 	u8 query_bit;
108 };
109 
110 struct transaction {
111 	const u8 *wdata;
112 	u8 *rdata;
113 	unsigned short irq_count;
114 	u8 command;
115 	u8 wi;
116 	u8 ri;
117 	u8 wlen;
118 	u8 rlen;
119 	u8 flags;
120 };
121 
122 struct acpi_ec *boot_ec, *first_ec;
123 EXPORT_SYMBOL(first_ec);
124 
125 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
126 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
127 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
128 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
129 
130 /* --------------------------------------------------------------------------
131                              Transaction Management
132    -------------------------------------------------------------------------- */
133 
134 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
135 {
136 	u8 x = inb(ec->command_addr);
137 	pr_debug("EC_SC(R) = 0x%2.2x "
138 		 "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d\n",
139 		 x,
140 		 !!(x & ACPI_EC_FLAG_SCI),
141 		 !!(x & ACPI_EC_FLAG_BURST),
142 		 !!(x & ACPI_EC_FLAG_CMD),
143 		 !!(x & ACPI_EC_FLAG_IBF),
144 		 !!(x & ACPI_EC_FLAG_OBF));
145 	return x;
146 }
147 
148 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
149 {
150 	u8 x = inb(ec->data_addr);
151 	pr_debug("EC_DATA(R) = 0x%2.2x\n", x);
152 	return x;
153 }
154 
155 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
156 {
157 	pr_debug("EC_SC(W) = 0x%2.2x\n", command);
158 	outb(command, ec->command_addr);
159 }
160 
161 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
162 {
163 	pr_debug("EC_DATA(W) = 0x%2.2x\n", data);
164 	outb(data, ec->data_addr);
165 }
166 
167 static int ec_transaction_completed(struct acpi_ec *ec)
168 {
169 	unsigned long flags;
170 	int ret = 0;
171 	spin_lock_irqsave(&ec->lock, flags);
172 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
173 		ret = 1;
174 	spin_unlock_irqrestore(&ec->lock, flags);
175 	return ret;
176 }
177 
178 static bool advance_transaction(struct acpi_ec *ec)
179 {
180 	struct transaction *t;
181 	u8 status;
182 	bool wakeup = false;
183 
184 	pr_debug("===== %s =====\n", in_interrupt() ? "IRQ" : "TASK");
185 	status = acpi_ec_read_status(ec);
186 	t = ec->curr;
187 	if (!t)
188 		goto err;
189 	if (t->flags & ACPI_EC_COMMAND_POLL) {
190 		if (t->wlen > t->wi) {
191 			if ((status & ACPI_EC_FLAG_IBF) == 0)
192 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
193 			else
194 				goto err;
195 		} else if (t->rlen > t->ri) {
196 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
197 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
198 				if (t->rlen == t->ri) {
199 					t->flags |= ACPI_EC_COMMAND_COMPLETE;
200 					wakeup = true;
201 				}
202 			} else
203 				goto err;
204 		} else if (t->wlen == t->wi &&
205 			   (status & ACPI_EC_FLAG_IBF) == 0) {
206 			t->flags |= ACPI_EC_COMMAND_COMPLETE;
207 			wakeup = true;
208 		}
209 		return wakeup;
210 	} else {
211 		if ((status & ACPI_EC_FLAG_IBF) == 0) {
212 			acpi_ec_write_cmd(ec, t->command);
213 			t->flags |= ACPI_EC_COMMAND_POLL;
214 		} else
215 			goto err;
216 		return wakeup;
217 	}
218 err:
219 	/*
220 	 * If SCI bit is set, then don't think it's a false IRQ
221 	 * otherwise will take a not handled IRQ as a false one.
222 	 */
223 	if (!(status & ACPI_EC_FLAG_SCI)) {
224 		if (in_interrupt() && t)
225 			++t->irq_count;
226 	}
227 	return wakeup;
228 }
229 
230 static void start_transaction(struct acpi_ec *ec)
231 {
232 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
233 	ec->curr->flags = 0;
234 	(void)advance_transaction(ec);
235 }
236 
237 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data);
238 
239 static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
240 {
241 	if (state & ACPI_EC_FLAG_SCI) {
242 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
243 			return acpi_ec_sync_query(ec, NULL);
244 	}
245 	return 0;
246 }
247 
248 static int ec_poll(struct acpi_ec *ec)
249 {
250 	unsigned long flags;
251 	int repeat = 5; /* number of command restarts */
252 	while (repeat--) {
253 		unsigned long delay = jiffies +
254 			msecs_to_jiffies(ec_delay);
255 		do {
256 			/* don't sleep with disabled interrupts */
257 			if (EC_FLAGS_MSI || irqs_disabled()) {
258 				udelay(ACPI_EC_MSI_UDELAY);
259 				if (ec_transaction_completed(ec))
260 					return 0;
261 			} else {
262 				if (wait_event_timeout(ec->wait,
263 						ec_transaction_completed(ec),
264 						msecs_to_jiffies(1)))
265 					return 0;
266 			}
267 			spin_lock_irqsave(&ec->lock, flags);
268 			(void)advance_transaction(ec);
269 			spin_unlock_irqrestore(&ec->lock, flags);
270 		} while (time_before(jiffies, delay));
271 		pr_debug("controller reset, restart transaction\n");
272 		spin_lock_irqsave(&ec->lock, flags);
273 		start_transaction(ec);
274 		spin_unlock_irqrestore(&ec->lock, flags);
275 	}
276 	return -ETIME;
277 }
278 
279 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
280 					struct transaction *t)
281 {
282 	unsigned long tmp;
283 	int ret = 0;
284 	if (EC_FLAGS_MSI)
285 		udelay(ACPI_EC_MSI_UDELAY);
286 	/* start transaction */
287 	spin_lock_irqsave(&ec->lock, tmp);
288 	/* following two actions should be kept atomic */
289 	ec->curr = t;
290 	start_transaction(ec);
291 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
292 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
293 	spin_unlock_irqrestore(&ec->lock, tmp);
294 	ret = ec_poll(ec);
295 	spin_lock_irqsave(&ec->lock, tmp);
296 	ec->curr = NULL;
297 	spin_unlock_irqrestore(&ec->lock, tmp);
298 	return ret;
299 }
300 
301 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
302 {
303 	int status;
304 	u32 glk;
305 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
306 		return -EINVAL;
307 	if (t->rdata)
308 		memset(t->rdata, 0, t->rlen);
309 	mutex_lock(&ec->mutex);
310 	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
311 		status = -EINVAL;
312 		goto unlock;
313 	}
314 	if (ec->global_lock) {
315 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
316 		if (ACPI_FAILURE(status)) {
317 			status = -ENODEV;
318 			goto unlock;
319 		}
320 	}
321 	pr_debug("transaction start (cmd=0x%02x, addr=0x%02x)\n",
322 			t->command, t->wdata ? t->wdata[0] : 0);
323 	/* disable GPE during transaction if storm is detected */
324 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
325 		/* It has to be disabled, so that it doesn't trigger. */
326 		acpi_disable_gpe(NULL, ec->gpe);
327 	}
328 
329 	status = acpi_ec_transaction_unlocked(ec, t);
330 
331 	/* check if we received SCI during transaction */
332 	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
333 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
334 		msleep(1);
335 		/* It is safe to enable the GPE outside of the transaction. */
336 		acpi_enable_gpe(NULL, ec->gpe);
337 	} else if (t->irq_count > ec_storm_threshold) {
338 		pr_info("GPE storm detected(%d GPEs), "
339 			"transactions will use polling mode\n",
340 			t->irq_count);
341 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
342 	}
343 	pr_debug("transaction end\n");
344 	if (ec->global_lock)
345 		acpi_release_global_lock(glk);
346 unlock:
347 	mutex_unlock(&ec->mutex);
348 	return status;
349 }
350 
351 static int acpi_ec_burst_enable(struct acpi_ec *ec)
352 {
353 	u8 d;
354 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
355 				.wdata = NULL, .rdata = &d,
356 				.wlen = 0, .rlen = 1};
357 
358 	return acpi_ec_transaction(ec, &t);
359 }
360 
361 static int acpi_ec_burst_disable(struct acpi_ec *ec)
362 {
363 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
364 				.wdata = NULL, .rdata = NULL,
365 				.wlen = 0, .rlen = 0};
366 
367 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
368 				acpi_ec_transaction(ec, &t) : 0;
369 }
370 
371 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
372 {
373 	int result;
374 	u8 d;
375 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
376 				.wdata = &address, .rdata = &d,
377 				.wlen = 1, .rlen = 1};
378 
379 	result = acpi_ec_transaction(ec, &t);
380 	*data = d;
381 	return result;
382 }
383 
384 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
385 {
386 	u8 wdata[2] = { address, data };
387 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
388 				.wdata = wdata, .rdata = NULL,
389 				.wlen = 2, .rlen = 0};
390 
391 	return acpi_ec_transaction(ec, &t);
392 }
393 
394 int ec_read(u8 addr, u8 *val)
395 {
396 	int err;
397 	u8 temp_data;
398 
399 	if (!first_ec)
400 		return -ENODEV;
401 
402 	err = acpi_ec_read(first_ec, addr, &temp_data);
403 
404 	if (!err) {
405 		*val = temp_data;
406 		return 0;
407 	} else
408 		return err;
409 }
410 
411 EXPORT_SYMBOL(ec_read);
412 
413 int ec_write(u8 addr, u8 val)
414 {
415 	int err;
416 
417 	if (!first_ec)
418 		return -ENODEV;
419 
420 	err = acpi_ec_write(first_ec, addr, val);
421 
422 	return err;
423 }
424 
425 EXPORT_SYMBOL(ec_write);
426 
427 int ec_transaction(u8 command,
428 		   const u8 * wdata, unsigned wdata_len,
429 		   u8 * rdata, unsigned rdata_len)
430 {
431 	struct transaction t = {.command = command,
432 				.wdata = wdata, .rdata = rdata,
433 				.wlen = wdata_len, .rlen = rdata_len};
434 	if (!first_ec)
435 		return -ENODEV;
436 
437 	return acpi_ec_transaction(first_ec, &t);
438 }
439 
440 EXPORT_SYMBOL(ec_transaction);
441 
442 /* Get the handle to the EC device */
443 acpi_handle ec_get_handle(void)
444 {
445 	if (!first_ec)
446 		return NULL;
447 	return first_ec->handle;
448 }
449 
450 EXPORT_SYMBOL(ec_get_handle);
451 
452 /*
453  * Process _Q events that might have accumulated in the EC.
454  * Run with locked ec mutex.
455  */
456 static void acpi_ec_clear(struct acpi_ec *ec)
457 {
458 	int i, status;
459 	u8 value = 0;
460 
461 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
462 		status = acpi_ec_sync_query(ec, &value);
463 		if (status || !value)
464 			break;
465 	}
466 
467 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
468 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
469 	else
470 		pr_info("%d stale EC events cleared\n", i);
471 }
472 
473 void acpi_ec_block_transactions(void)
474 {
475 	struct acpi_ec *ec = first_ec;
476 
477 	if (!ec)
478 		return;
479 
480 	mutex_lock(&ec->mutex);
481 	/* Prevent transactions from being carried out */
482 	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
483 	mutex_unlock(&ec->mutex);
484 }
485 
486 void acpi_ec_unblock_transactions(void)
487 {
488 	struct acpi_ec *ec = first_ec;
489 
490 	if (!ec)
491 		return;
492 
493 	mutex_lock(&ec->mutex);
494 	/* Allow transactions to be carried out again */
495 	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
496 
497 	if (EC_FLAGS_CLEAR_ON_RESUME)
498 		acpi_ec_clear(ec);
499 
500 	mutex_unlock(&ec->mutex);
501 }
502 
503 void acpi_ec_unblock_transactions_early(void)
504 {
505 	/*
506 	 * Allow transactions to happen again (this function is called from
507 	 * atomic context during wakeup, so we don't need to acquire the mutex).
508 	 */
509 	if (first_ec)
510 		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
511 }
512 
513 static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
514 {
515 	int result;
516 	u8 d;
517 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
518 				.wdata = NULL, .rdata = &d,
519 				.wlen = 0, .rlen = 1};
520 	if (!ec || !data)
521 		return -EINVAL;
522 	/*
523 	 * Query the EC to find out which _Qxx method we need to evaluate.
524 	 * Note that successful completion of the query causes the ACPI_EC_SCI
525 	 * bit to be cleared (and thus clearing the interrupt source).
526 	 */
527 	result = acpi_ec_transaction_unlocked(ec, &t);
528 	if (result)
529 		return result;
530 	if (!d)
531 		return -ENODATA;
532 	*data = d;
533 	return 0;
534 }
535 
536 /* --------------------------------------------------------------------------
537                                 Event Management
538    -------------------------------------------------------------------------- */
539 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
540 			      acpi_handle handle, acpi_ec_query_func func,
541 			      void *data)
542 {
543 	struct acpi_ec_query_handler *handler =
544 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
545 	if (!handler)
546 		return -ENOMEM;
547 
548 	handler->query_bit = query_bit;
549 	handler->handle = handle;
550 	handler->func = func;
551 	handler->data = data;
552 	mutex_lock(&ec->mutex);
553 	list_add(&handler->node, &ec->list);
554 	mutex_unlock(&ec->mutex);
555 	return 0;
556 }
557 
558 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
559 
560 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
561 {
562 	struct acpi_ec_query_handler *handler, *tmp;
563 	mutex_lock(&ec->mutex);
564 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
565 		if (query_bit == handler->query_bit) {
566 			list_del(&handler->node);
567 			kfree(handler);
568 		}
569 	}
570 	mutex_unlock(&ec->mutex);
571 }
572 
573 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
574 
575 static void acpi_ec_run(void *cxt)
576 {
577 	struct acpi_ec_query_handler *handler = cxt;
578 	if (!handler)
579 		return;
580 	pr_debug("start query execution\n");
581 	if (handler->func)
582 		handler->func(handler->data);
583 	else if (handler->handle)
584 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
585 	pr_debug("stop query execution\n");
586 	kfree(handler);
587 }
588 
589 static int acpi_ec_sync_query(struct acpi_ec *ec, u8 *data)
590 {
591 	u8 value = 0;
592 	int status;
593 	struct acpi_ec_query_handler *handler, *copy;
594 
595 	status = acpi_ec_query_unlocked(ec, &value);
596 	if (data)
597 		*data = value;
598 	if (status)
599 		return status;
600 
601 	list_for_each_entry(handler, &ec->list, node) {
602 		if (value == handler->query_bit) {
603 			/* have custom handler for this bit */
604 			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
605 			if (!copy)
606 				return -ENOMEM;
607 			memcpy(copy, handler, sizeof(*copy));
608 			pr_debug("push query execution (0x%2x) on queue\n",
609 				value);
610 			return acpi_os_execute((copy->func) ?
611 				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
612 				acpi_ec_run, copy);
613 		}
614 	}
615 	return 0;
616 }
617 
618 static void acpi_ec_gpe_query(void *ec_cxt)
619 {
620 	struct acpi_ec *ec = ec_cxt;
621 	if (!ec)
622 		return;
623 	mutex_lock(&ec->mutex);
624 	acpi_ec_sync_query(ec, NULL);
625 	mutex_unlock(&ec->mutex);
626 }
627 
628 static int ec_check_sci(struct acpi_ec *ec, u8 state)
629 {
630 	if (state & ACPI_EC_FLAG_SCI) {
631 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
632 			pr_debug("push gpe query to the queue\n");
633 			return acpi_os_execute(OSL_NOTIFY_HANDLER,
634 				acpi_ec_gpe_query, ec);
635 		}
636 	}
637 	return 0;
638 }
639 
640 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
641 	u32 gpe_number, void *data)
642 {
643 	unsigned long flags;
644 	struct acpi_ec *ec = data;
645 
646 	spin_lock_irqsave(&ec->lock, flags);
647 	if (advance_transaction(ec))
648 		wake_up(&ec->wait);
649 	spin_unlock_irqrestore(&ec->lock, flags);
650 	ec_check_sci(ec, acpi_ec_read_status(ec));
651 	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
652 }
653 
654 /* --------------------------------------------------------------------------
655                              Address Space Management
656    -------------------------------------------------------------------------- */
657 
658 static acpi_status
659 acpi_ec_space_handler(u32 function, acpi_physical_address address,
660 		      u32 bits, u64 *value64,
661 		      void *handler_context, void *region_context)
662 {
663 	struct acpi_ec *ec = handler_context;
664 	int result = 0, i, bytes = bits / 8;
665 	u8 *value = (u8 *)value64;
666 
667 	if ((address > 0xFF) || !value || !handler_context)
668 		return AE_BAD_PARAMETER;
669 
670 	if (function != ACPI_READ && function != ACPI_WRITE)
671 		return AE_BAD_PARAMETER;
672 
673 	if (EC_FLAGS_MSI || bits > 8)
674 		acpi_ec_burst_enable(ec);
675 
676 	for (i = 0; i < bytes; ++i, ++address, ++value)
677 		result = (function == ACPI_READ) ?
678 			acpi_ec_read(ec, address, value) :
679 			acpi_ec_write(ec, address, *value);
680 
681 	if (EC_FLAGS_MSI || bits > 8)
682 		acpi_ec_burst_disable(ec);
683 
684 	switch (result) {
685 	case -EINVAL:
686 		return AE_BAD_PARAMETER;
687 		break;
688 	case -ENODEV:
689 		return AE_NOT_FOUND;
690 		break;
691 	case -ETIME:
692 		return AE_TIME;
693 		break;
694 	default:
695 		return AE_OK;
696 	}
697 }
698 
699 /* --------------------------------------------------------------------------
700                                Driver Interface
701    -------------------------------------------------------------------------- */
702 static acpi_status
703 ec_parse_io_ports(struct acpi_resource *resource, void *context);
704 
705 static struct acpi_ec *make_acpi_ec(void)
706 {
707 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
708 	if (!ec)
709 		return NULL;
710 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
711 	mutex_init(&ec->mutex);
712 	init_waitqueue_head(&ec->wait);
713 	INIT_LIST_HEAD(&ec->list);
714 	spin_lock_init(&ec->lock);
715 	return ec;
716 }
717 
718 static acpi_status
719 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
720 			       void *context, void **return_value)
721 {
722 	char node_name[5];
723 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
724 	struct acpi_ec *ec = context;
725 	int value = 0;
726 	acpi_status status;
727 
728 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
729 
730 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
731 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
732 	}
733 	return AE_OK;
734 }
735 
736 static acpi_status
737 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
738 {
739 	acpi_status status;
740 	unsigned long long tmp = 0;
741 
742 	struct acpi_ec *ec = context;
743 
744 	/* clear addr values, ec_parse_io_ports depend on it */
745 	ec->command_addr = ec->data_addr = 0;
746 
747 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
748 				     ec_parse_io_ports, ec);
749 	if (ACPI_FAILURE(status))
750 		return status;
751 
752 	/* Get GPE bit assignment (EC events). */
753 	/* TODO: Add support for _GPE returning a package */
754 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
755 	if (ACPI_FAILURE(status))
756 		return status;
757 	ec->gpe = tmp;
758 	/* Use the global lock for all EC transactions? */
759 	tmp = 0;
760 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
761 	ec->global_lock = tmp;
762 	ec->handle = handle;
763 	return AE_CTRL_TERMINATE;
764 }
765 
766 static int ec_install_handlers(struct acpi_ec *ec)
767 {
768 	acpi_status status;
769 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
770 		return 0;
771 	status = acpi_install_gpe_handler(NULL, ec->gpe,
772 				  ACPI_GPE_EDGE_TRIGGERED,
773 				  &acpi_ec_gpe_handler, ec);
774 	if (ACPI_FAILURE(status))
775 		return -ENODEV;
776 
777 	acpi_enable_gpe(NULL, ec->gpe);
778 	status = acpi_install_address_space_handler(ec->handle,
779 						    ACPI_ADR_SPACE_EC,
780 						    &acpi_ec_space_handler,
781 						    NULL, ec);
782 	if (ACPI_FAILURE(status)) {
783 		if (status == AE_NOT_FOUND) {
784 			/*
785 			 * Maybe OS fails in evaluating the _REG object.
786 			 * The AE_NOT_FOUND error will be ignored and OS
787 			 * continue to initialize EC.
788 			 */
789 			pr_err("Fail in evaluating the _REG object"
790 				" of EC device. Broken bios is suspected.\n");
791 		} else {
792 			acpi_disable_gpe(NULL, ec->gpe);
793 			acpi_remove_gpe_handler(NULL, ec->gpe,
794 				&acpi_ec_gpe_handler);
795 			return -ENODEV;
796 		}
797 	}
798 
799 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
800 	return 0;
801 }
802 
803 static void ec_remove_handlers(struct acpi_ec *ec)
804 {
805 	acpi_disable_gpe(NULL, ec->gpe);
806 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
807 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
808 		pr_err("failed to remove space handler\n");
809 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
810 				&acpi_ec_gpe_handler)))
811 		pr_err("failed to remove gpe handler\n");
812 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
813 }
814 
815 static int acpi_ec_add(struct acpi_device *device)
816 {
817 	struct acpi_ec *ec = NULL;
818 	int ret;
819 
820 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
821 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
822 
823 	/* Check for boot EC */
824 	if (boot_ec &&
825 	    (boot_ec->handle == device->handle ||
826 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
827 		ec = boot_ec;
828 		boot_ec = NULL;
829 	} else {
830 		ec = make_acpi_ec();
831 		if (!ec)
832 			return -ENOMEM;
833 	}
834 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
835 		AE_CTRL_TERMINATE) {
836 			kfree(ec);
837 			return -EINVAL;
838 	}
839 
840 	/* Find and register all query methods */
841 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
842 			    acpi_ec_register_query_methods, NULL, ec, NULL);
843 
844 	if (!first_ec)
845 		first_ec = ec;
846 	device->driver_data = ec;
847 
848 	ret = !!request_region(ec->data_addr, 1, "EC data");
849 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
850 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
851 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
852 
853 	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
854 			  ec->gpe, ec->command_addr, ec->data_addr);
855 
856 	ret = ec_install_handlers(ec);
857 
858 	/* EC is fully operational, allow queries */
859 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
860 
861 	/* Clear stale _Q events if hardware might require that */
862 	if (EC_FLAGS_CLEAR_ON_RESUME) {
863 		mutex_lock(&ec->mutex);
864 		acpi_ec_clear(ec);
865 		mutex_unlock(&ec->mutex);
866 	}
867 	return ret;
868 }
869 
870 static int acpi_ec_remove(struct acpi_device *device)
871 {
872 	struct acpi_ec *ec;
873 	struct acpi_ec_query_handler *handler, *tmp;
874 
875 	if (!device)
876 		return -EINVAL;
877 
878 	ec = acpi_driver_data(device);
879 	ec_remove_handlers(ec);
880 	mutex_lock(&ec->mutex);
881 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
882 		list_del(&handler->node);
883 		kfree(handler);
884 	}
885 	mutex_unlock(&ec->mutex);
886 	release_region(ec->data_addr, 1);
887 	release_region(ec->command_addr, 1);
888 	device->driver_data = NULL;
889 	if (ec == first_ec)
890 		first_ec = NULL;
891 	kfree(ec);
892 	return 0;
893 }
894 
895 static acpi_status
896 ec_parse_io_ports(struct acpi_resource *resource, void *context)
897 {
898 	struct acpi_ec *ec = context;
899 
900 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
901 		return AE_OK;
902 
903 	/*
904 	 * The first address region returned is the data port, and
905 	 * the second address region returned is the status/command
906 	 * port.
907 	 */
908 	if (ec->data_addr == 0)
909 		ec->data_addr = resource->data.io.minimum;
910 	else if (ec->command_addr == 0)
911 		ec->command_addr = resource->data.io.minimum;
912 	else
913 		return AE_CTRL_TERMINATE;
914 
915 	return AE_OK;
916 }
917 
918 int __init acpi_boot_ec_enable(void)
919 {
920 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
921 		return 0;
922 	if (!ec_install_handlers(boot_ec)) {
923 		first_ec = boot_ec;
924 		return 0;
925 	}
926 	return -EFAULT;
927 }
928 
929 static const struct acpi_device_id ec_device_ids[] = {
930 	{"PNP0C09", 0},
931 	{"", 0},
932 };
933 
934 /* Some BIOS do not survive early DSDT scan, skip it */
935 static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
936 {
937 	EC_FLAGS_SKIP_DSDT_SCAN = 1;
938 	return 0;
939 }
940 
941 /* ASUStek often supplies us with broken ECDT, validate it */
942 static int ec_validate_ecdt(const struct dmi_system_id *id)
943 {
944 	EC_FLAGS_VALIDATE_ECDT = 1;
945 	return 0;
946 }
947 
948 /* MSI EC needs special treatment, enable it */
949 static int ec_flag_msi(const struct dmi_system_id *id)
950 {
951 	pr_debug("Detected MSI hardware, enabling workarounds.\n");
952 	EC_FLAGS_MSI = 1;
953 	EC_FLAGS_VALIDATE_ECDT = 1;
954 	return 0;
955 }
956 
957 /*
958  * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
959  * the GPE storm threshold back to 20
960  */
961 static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
962 {
963 	pr_debug("Setting the EC GPE storm threshold to 20\n");
964 	ec_storm_threshold  = 20;
965 	return 0;
966 }
967 
968 /*
969  * On some hardware it is necessary to clear events accumulated by the EC during
970  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
971  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
972  *
973  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
974  *
975  * Ideally, the EC should also be instructed NOT to accumulate events during
976  * sleep (which Windows seems to do somehow), but the interface to control this
977  * behaviour is not known at this time.
978  *
979  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
980  * however it is very likely that other Samsung models are affected.
981  *
982  * On systems which don't accumulate _Q events during sleep, this extra check
983  * should be harmless.
984  */
985 static int ec_clear_on_resume(const struct dmi_system_id *id)
986 {
987 	pr_debug("Detected system needing EC poll on resume.\n");
988 	EC_FLAGS_CLEAR_ON_RESUME = 1;
989 	return 0;
990 }
991 
992 static struct dmi_system_id ec_dmi_table[] __initdata = {
993 	{
994 	ec_skip_dsdt_scan, "Compal JFL92", {
995 	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
996 	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
997 	{
998 	ec_flag_msi, "MSI hardware", {
999 	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
1000 	{
1001 	ec_flag_msi, "MSI hardware", {
1002 	DMI_MATCH(DMI_SYS_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, "MSI hardware", {
1008 	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
1009 	{
1010 	ec_flag_msi, "Quanta hardware", {
1011 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1012 	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
1013 	{
1014 	ec_flag_msi, "Quanta hardware", {
1015 	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
1016 	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
1017 	{
1018 	ec_validate_ecdt, "ASUS hardware", {
1019 	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
1020 	{
1021 	ec_validate_ecdt, "ASUS hardware", {
1022 	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
1023 	{
1024 	ec_enlarge_storm_threshold, "CLEVO hardware", {
1025 	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
1026 	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
1027 	{
1028 	ec_skip_dsdt_scan, "HP Folio 13", {
1029 	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1030 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
1031 	{
1032 	ec_validate_ecdt, "ASUS hardware", {
1033 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
1034 	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
1035 	{
1036 	ec_clear_on_resume, "Samsung hardware", {
1037 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1038 	{},
1039 };
1040 
1041 int __init acpi_ec_ecdt_probe(void)
1042 {
1043 	acpi_status status;
1044 	struct acpi_ec *saved_ec = NULL;
1045 	struct acpi_table_ecdt *ecdt_ptr;
1046 
1047 	boot_ec = make_acpi_ec();
1048 	if (!boot_ec)
1049 		return -ENOMEM;
1050 	/*
1051 	 * Generate a boot ec context
1052 	 */
1053 	dmi_check_system(ec_dmi_table);
1054 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1055 				(struct acpi_table_header **)&ecdt_ptr);
1056 	if (ACPI_SUCCESS(status)) {
1057 		pr_info("EC description table is found, configuring boot EC\n");
1058 		boot_ec->command_addr = ecdt_ptr->control.address;
1059 		boot_ec->data_addr = ecdt_ptr->data.address;
1060 		boot_ec->gpe = ecdt_ptr->gpe;
1061 		boot_ec->handle = ACPI_ROOT_OBJECT;
1062 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
1063 		/* Don't trust ECDT, which comes from ASUSTek */
1064 		if (!EC_FLAGS_VALIDATE_ECDT)
1065 			goto install;
1066 		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
1067 		if (!saved_ec)
1068 			return -ENOMEM;
1069 	/* fall through */
1070 	}
1071 
1072 	if (EC_FLAGS_SKIP_DSDT_SCAN) {
1073 		kfree(saved_ec);
1074 		return -ENODEV;
1075 	}
1076 
1077 	/* This workaround is needed only on some broken machines,
1078 	 * which require early EC, but fail to provide ECDT */
1079 	pr_debug("Look up EC in DSDT\n");
1080 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1081 					boot_ec, NULL);
1082 	/* Check that acpi_get_devices actually find something */
1083 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1084 		goto error;
1085 	if (saved_ec) {
1086 		/* try to find good ECDT from ASUSTek */
1087 		if (saved_ec->command_addr != boot_ec->command_addr ||
1088 		    saved_ec->data_addr != boot_ec->data_addr ||
1089 		    saved_ec->gpe != boot_ec->gpe ||
1090 		    saved_ec->handle != boot_ec->handle)
1091 			pr_info("ASUSTek keeps feeding us with broken "
1092 			"ECDT tables, which are very hard to workaround. "
1093 			"Trying to use DSDT EC info instead. Please send "
1094 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1095 		kfree(saved_ec);
1096 		saved_ec = NULL;
1097 	} else {
1098 		/* We really need to limit this workaround, the only ASUS,
1099 		* which needs it, has fake EC._INI method, so use it as flag.
1100 		* Keep boot_ec struct as it will be needed soon.
1101 		*/
1102 		if (!dmi_name_in_vendors("ASUS") ||
1103 		    !acpi_has_method(boot_ec->handle, "_INI"))
1104 			return -ENODEV;
1105 	}
1106 install:
1107 	if (!ec_install_handlers(boot_ec)) {
1108 		first_ec = boot_ec;
1109 		return 0;
1110 	}
1111 error:
1112 	kfree(boot_ec);
1113 	kfree(saved_ec);
1114 	boot_ec = NULL;
1115 	return -ENODEV;
1116 }
1117 
1118 static struct acpi_driver acpi_ec_driver = {
1119 	.name = "ec",
1120 	.class = ACPI_EC_CLASS,
1121 	.ids = ec_device_ids,
1122 	.ops = {
1123 		.add = acpi_ec_add,
1124 		.remove = acpi_ec_remove,
1125 		},
1126 };
1127 
1128 int __init acpi_ec_init(void)
1129 {
1130 	int result = 0;
1131 
1132 	/* Now register the driver for the EC */
1133 	result = acpi_bus_register_driver(&acpi_ec_driver);
1134 	if (result < 0)
1135 		return -ENODEV;
1136 
1137 	return result;
1138 }
1139 
1140 /* EC driver currently not unloadable */
1141 #if 0
1142 static void __exit acpi_ec_exit(void)
1143 {
1144 
1145 	acpi_bus_unregister_driver(&acpi_ec_driver);
1146 	return;
1147 }
1148 #endif	/* 0 */
1149