xref: /linux/drivers/acpi/ec.c (revision b233b28eac0cc37d07c2d007ea08c86c778c5af4)
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/proc_fs.h>
38 #include <linux/seq_file.h>
39 #include <linux/interrupt.h>
40 #include <linux/list.h>
41 #include <linux/spinlock.h>
42 #include <asm/io.h>
43 #include <acpi/acpi_bus.h>
44 #include <acpi/acpi_drivers.h>
45 
46 #define ACPI_EC_CLASS			"embedded_controller"
47 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
48 #define ACPI_EC_FILE_INFO		"info"
49 
50 #undef PREFIX
51 #define PREFIX				"ACPI: EC: "
52 
53 /* EC status register */
54 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
55 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
56 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
57 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
58 
59 /* EC commands */
60 enum ec_command {
61 	ACPI_EC_COMMAND_READ = 0x80,
62 	ACPI_EC_COMMAND_WRITE = 0x81,
63 	ACPI_EC_BURST_ENABLE = 0x82,
64 	ACPI_EC_BURST_DISABLE = 0x83,
65 	ACPI_EC_COMMAND_QUERY = 0x84,
66 };
67 
68 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
69 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
70 #define ACPI_EC_UDELAY		100	/* Wait 100us before polling EC again */
71 
72 #define ACPI_EC_STORM_THRESHOLD 8	/* number of false interrupts
73 					   per one transaction */
74 
75 enum {
76 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
77 	EC_FLAGS_GPE_MODE,		/* Expect GPE to be sent
78 					 * for status change */
79 	EC_FLAGS_NO_GPE,		/* Don't use GPE mode */
80 	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
81 	EC_FLAGS_HANDLERS_INSTALLED	/* Handlers for GPE and
82 					 * OpReg are installed */
83 };
84 
85 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
86 /* External interfaces use first EC only, so remember */
87 typedef int (*acpi_ec_query_func) (void *data);
88 
89 struct acpi_ec_query_handler {
90 	struct list_head node;
91 	acpi_ec_query_func func;
92 	acpi_handle handle;
93 	void *data;
94 	u8 query_bit;
95 };
96 
97 struct transaction {
98 	const u8 *wdata;
99 	u8 *rdata;
100 	unsigned short irq_count;
101 	u8 command;
102 	u8 wi;
103 	u8 ri;
104 	u8 wlen;
105 	u8 rlen;
106 	bool done;
107 };
108 
109 static struct acpi_ec {
110 	acpi_handle handle;
111 	unsigned long gpe;
112 	unsigned long command_addr;
113 	unsigned long data_addr;
114 	unsigned long global_lock;
115 	unsigned long flags;
116 	struct mutex lock;
117 	wait_queue_head_t wait;
118 	struct list_head list;
119 	struct transaction *curr;
120 	spinlock_t curr_lock;
121 } *boot_ec, *first_ec;
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(PREFIX "---> 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(PREFIX "---> 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(PREFIX "<--- 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(PREFIX "<--- 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->curr_lock, flags);
158 	if (!ec->curr || ec->curr->done)
159 		ret = 1;
160 	spin_unlock_irqrestore(&ec->curr_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 gpe_transaction(struct acpi_ec *ec, u8 status)
172 {
173 	unsigned long flags;
174 	spin_lock_irqsave(&ec->curr_lock, flags);
175 	if (!ec->curr)
176 		goto unlock;
177 	if (ec->curr->wlen > ec->curr->wi) {
178 		if ((status & ACPI_EC_FLAG_IBF) == 0)
179 			acpi_ec_write_data(ec,
180 				ec->curr->wdata[ec->curr->wi++]);
181 		else
182 			goto err;
183 	} else if (ec->curr->rlen > ec->curr->ri) {
184 		if ((status & ACPI_EC_FLAG_OBF) == 1) {
185 			ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
186 			if (ec->curr->rlen == ec->curr->ri)
187 				ec->curr->done = true;
188 		} else
189 			goto err;
190 	} else if (ec->curr->wlen == ec->curr->wi &&
191 		   (status & ACPI_EC_FLAG_IBF) == 0)
192 		ec->curr->done = true;
193 	goto unlock;
194 err:
195 	/* false interrupt, state didn't change */
196 	if (in_interrupt())
197 		++ec->curr->irq_count;
198 unlock:
199 	spin_unlock_irqrestore(&ec->curr_lock, flags);
200 }
201 
202 static int acpi_ec_wait(struct acpi_ec *ec)
203 {
204 	if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
205 			       msecs_to_jiffies(ACPI_EC_DELAY)))
206 		return 0;
207 	/* try restart command if we get any false interrupts */
208 	if (ec->curr->irq_count &&
209 	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
210 		pr_debug(PREFIX "controller reset, restart transaction\n");
211 		start_transaction(ec);
212 		if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
213 					msecs_to_jiffies(ACPI_EC_DELAY)))
214 			return 0;
215 	}
216 	/* missing GPEs, switch back to poll mode */
217 	if (printk_ratelimit())
218 		pr_info(PREFIX "missing confirmations, "
219 				"switch off interrupt mode.\n");
220 	set_bit(EC_FLAGS_NO_GPE, &ec->flags);
221 	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
222 	return 1;
223 }
224 
225 static void acpi_ec_gpe_query(void *ec_cxt);
226 
227 static int ec_check_sci(struct acpi_ec *ec, u8 state)
228 {
229 	if (state & ACPI_EC_FLAG_SCI) {
230 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
231 			return acpi_os_execute(OSL_EC_BURST_HANDLER,
232 				acpi_ec_gpe_query, ec);
233 	}
234 	return 0;
235 }
236 
237 static int ec_poll(struct acpi_ec *ec)
238 {
239 	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
240 	udelay(ACPI_EC_UDELAY);
241 	while (time_before(jiffies, delay)) {
242 		gpe_transaction(ec, acpi_ec_read_status(ec));
243 		udelay(ACPI_EC_UDELAY);
244 		if (ec_transaction_done(ec))
245 			return 0;
246 	}
247 	return -ETIME;
248 }
249 
250 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
251 					struct transaction *t,
252 					int force_poll)
253 {
254 	unsigned long tmp;
255 	int ret = 0;
256 	pr_debug(PREFIX "transaction start\n");
257 	/* disable GPE during transaction if storm is detected */
258 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
259 		clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
260 		acpi_disable_gpe(NULL, ec->gpe);
261 	}
262 	/* start transaction */
263 	spin_lock_irqsave(&ec->curr_lock, tmp);
264 	/* following two actions should be kept atomic */
265 	ec->curr = t;
266 	start_transaction(ec);
267 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
268 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
269 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
270 	/* if we selected poll mode or failed in GPE-mode do a poll loop */
271 	if (force_poll ||
272 	    !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||
273 	    acpi_ec_wait(ec))
274 		ret = ec_poll(ec);
275 	pr_debug(PREFIX "transaction end\n");
276 	spin_lock_irqsave(&ec->curr_lock, tmp);
277 	ec->curr = NULL;
278 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
279 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
280 		/* check if we received SCI during transaction */
281 		ec_check_sci(ec, acpi_ec_read_status(ec));
282 		/* it is safe to enable GPE outside of transaction */
283 		acpi_enable_gpe(NULL, ec->gpe);
284 	} else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
285 		   t->irq_count > ACPI_EC_STORM_THRESHOLD) {
286 		pr_info(PREFIX "GPE storm detected, "
287 			"transactions will use polling mode\n");
288 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
289 	}
290 	return ret;
291 }
292 
293 static int ec_check_ibf0(struct acpi_ec *ec)
294 {
295 	u8 status = acpi_ec_read_status(ec);
296 	return (status & ACPI_EC_FLAG_IBF) == 0;
297 }
298 
299 static int ec_wait_ibf0(struct acpi_ec *ec)
300 {
301 	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
302 	/* interrupt wait manually if GPE mode is not active */
303 	unsigned long timeout = test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ?
304 		msecs_to_jiffies(ACPI_EC_DELAY) : msecs_to_jiffies(1);
305 	while (time_before(jiffies, delay))
306 		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec), timeout))
307 			return 0;
308 	return -ETIME;
309 }
310 
311 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t,
312 			       int force_poll)
313 {
314 	int status;
315 	u32 glk;
316 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
317 		return -EINVAL;
318 	if (t->rdata)
319 		memset(t->rdata, 0, t->rlen);
320 	mutex_lock(&ec->lock);
321 	if (ec->global_lock) {
322 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
323 		if (ACPI_FAILURE(status)) {
324 			status = -ENODEV;
325 			goto unlock;
326 		}
327 	}
328 	if (ec_wait_ibf0(ec)) {
329 		pr_err(PREFIX "input buffer is not empty, "
330 				"aborting transaction\n");
331 		status = -ETIME;
332 		goto end;
333 	}
334 	status = acpi_ec_transaction_unlocked(ec, t, force_poll);
335 end:
336 	if (ec->global_lock)
337 		acpi_release_global_lock(glk);
338 unlock:
339 	mutex_unlock(&ec->lock);
340 	return status;
341 }
342 
343 /*
344  * Note: samsung nv5000 doesn't work with ec burst mode.
345  * http://bugzilla.kernel.org/show_bug.cgi?id=4980
346  */
347 static int acpi_ec_burst_enable(struct acpi_ec *ec)
348 {
349 	u8 d;
350 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
351 				.wdata = NULL, .rdata = &d,
352 				.wlen = 0, .rlen = 1};
353 
354 	return acpi_ec_transaction(ec, &t, 0);
355 }
356 
357 static int acpi_ec_burst_disable(struct acpi_ec *ec)
358 {
359 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
360 				.wdata = NULL, .rdata = NULL,
361 				.wlen = 0, .rlen = 0};
362 
363 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
364 				acpi_ec_transaction(ec, &t, 0) : 0;
365 }
366 
367 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
368 {
369 	int result;
370 	u8 d;
371 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
372 				.wdata = &address, .rdata = &d,
373 				.wlen = 1, .rlen = 1};
374 
375 	result = acpi_ec_transaction(ec, &t, 0);
376 	*data = d;
377 	return result;
378 }
379 
380 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
381 {
382 	u8 wdata[2] = { address, data };
383 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
384 				.wdata = wdata, .rdata = NULL,
385 				.wlen = 2, .rlen = 0};
386 
387 	return acpi_ec_transaction(ec, &t, 0);
388 }
389 
390 /*
391  * Externally callable EC access functions. For now, assume 1 EC only
392  */
393 int ec_burst_enable(void)
394 {
395 	if (!first_ec)
396 		return -ENODEV;
397 	return acpi_ec_burst_enable(first_ec);
398 }
399 
400 EXPORT_SYMBOL(ec_burst_enable);
401 
402 int ec_burst_disable(void)
403 {
404 	if (!first_ec)
405 		return -ENODEV;
406 	return acpi_ec_burst_disable(first_ec);
407 }
408 
409 EXPORT_SYMBOL(ec_burst_disable);
410 
411 int ec_read(u8 addr, u8 * val)
412 {
413 	int err;
414 	u8 temp_data;
415 
416 	if (!first_ec)
417 		return -ENODEV;
418 
419 	err = acpi_ec_read(first_ec, addr, &temp_data);
420 
421 	if (!err) {
422 		*val = temp_data;
423 		return 0;
424 	} else
425 		return err;
426 }
427 
428 EXPORT_SYMBOL(ec_read);
429 
430 int ec_write(u8 addr, u8 val)
431 {
432 	int err;
433 
434 	if (!first_ec)
435 		return -ENODEV;
436 
437 	err = acpi_ec_write(first_ec, addr, val);
438 
439 	return err;
440 }
441 
442 EXPORT_SYMBOL(ec_write);
443 
444 int ec_transaction(u8 command,
445 		   const u8 * wdata, unsigned wdata_len,
446 		   u8 * rdata, unsigned rdata_len,
447 		   int force_poll)
448 {
449 	struct transaction t = {.command = command,
450 				.wdata = wdata, .rdata = rdata,
451 				.wlen = wdata_len, .rlen = rdata_len};
452 	if (!first_ec)
453 		return -ENODEV;
454 
455 	return acpi_ec_transaction(first_ec, &t, force_poll);
456 }
457 
458 EXPORT_SYMBOL(ec_transaction);
459 
460 static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
461 {
462 	int result;
463 	u8 d;
464 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
465 				.wdata = NULL, .rdata = &d,
466 				.wlen = 0, .rlen = 1};
467 	if (!ec || !data)
468 		return -EINVAL;
469 
470 	/*
471 	 * Query the EC to find out which _Qxx method we need to evaluate.
472 	 * Note that successful completion of the query causes the ACPI_EC_SCI
473 	 * bit to be cleared (and thus clearing the interrupt source).
474 	 */
475 
476 	result = acpi_ec_transaction(ec, &t, 0);
477 	if (result)
478 		return result;
479 
480 	if (!d)
481 		return -ENODATA;
482 
483 	*data = d;
484 	return 0;
485 }
486 
487 /* --------------------------------------------------------------------------
488                                 Event Management
489    -------------------------------------------------------------------------- */
490 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
491 			      acpi_handle handle, acpi_ec_query_func func,
492 			      void *data)
493 {
494 	struct acpi_ec_query_handler *handler =
495 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
496 	if (!handler)
497 		return -ENOMEM;
498 
499 	handler->query_bit = query_bit;
500 	handler->handle = handle;
501 	handler->func = func;
502 	handler->data = data;
503 	mutex_lock(&ec->lock);
504 	list_add(&handler->node, &ec->list);
505 	mutex_unlock(&ec->lock);
506 	return 0;
507 }
508 
509 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
510 
511 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
512 {
513 	struct acpi_ec_query_handler *handler, *tmp;
514 	mutex_lock(&ec->lock);
515 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
516 		if (query_bit == handler->query_bit) {
517 			list_del(&handler->node);
518 			kfree(handler);
519 		}
520 	}
521 	mutex_unlock(&ec->lock);
522 }
523 
524 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
525 
526 static void acpi_ec_gpe_query(void *ec_cxt)
527 {
528 	struct acpi_ec *ec = ec_cxt;
529 	u8 value = 0;
530 	struct acpi_ec_query_handler *handler, copy;
531 
532 	if (!ec || acpi_ec_query(ec, &value))
533 		return;
534 	mutex_lock(&ec->lock);
535 	list_for_each_entry(handler, &ec->list, node) {
536 		if (value == handler->query_bit) {
537 			/* have custom handler for this bit */
538 			memcpy(&copy, handler, sizeof(copy));
539 			mutex_unlock(&ec->lock);
540 			if (copy.func) {
541 				copy.func(copy.data);
542 			} else if (copy.handle) {
543 				acpi_evaluate_object(copy.handle, NULL, NULL, NULL);
544 			}
545 			return;
546 		}
547 	}
548 	mutex_unlock(&ec->lock);
549 }
550 
551 static u32 acpi_ec_gpe_handler(void *data)
552 {
553 	struct acpi_ec *ec = data;
554 	u8 status;
555 
556 	pr_debug(PREFIX "~~~> interrupt\n");
557 	status = acpi_ec_read_status(ec);
558 
559 	if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) {
560 		gpe_transaction(ec, status);
561 		if (ec_transaction_done(ec) &&
562 		    (status & ACPI_EC_FLAG_IBF) == 0)
563 			wake_up(&ec->wait);
564 	}
565 
566 	ec_check_sci(ec, status);
567 	if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
568 	    !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) {
569 		/* this is non-query, must be confirmation */
570 		if (!test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
571 			if (printk_ratelimit())
572 				pr_info(PREFIX "non-query interrupt received,"
573 					" switching to interrupt mode\n");
574 		} else {
575 			/* hush, STORM switches the mode every transaction */
576 			pr_debug(PREFIX "non-query interrupt received,"
577 				" switching to interrupt mode\n");
578 		}
579 		set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
580 	}
581 	return ACPI_INTERRUPT_HANDLED;
582 }
583 
584 /* --------------------------------------------------------------------------
585                              Address Space Management
586    -------------------------------------------------------------------------- */
587 
588 static acpi_status
589 acpi_ec_space_handler(u32 function, acpi_physical_address address,
590 		      u32 bits, acpi_integer *value,
591 		      void *handler_context, void *region_context)
592 {
593 	struct acpi_ec *ec = handler_context;
594 	int result = 0, i;
595 	u8 temp = 0;
596 
597 	if ((address > 0xFF) || !value || !handler_context)
598 		return AE_BAD_PARAMETER;
599 
600 	if (function != ACPI_READ && function != ACPI_WRITE)
601 		return AE_BAD_PARAMETER;
602 
603 	if (bits != 8 && acpi_strict)
604 		return AE_BAD_PARAMETER;
605 
606 	acpi_ec_burst_enable(ec);
607 
608 	if (function == ACPI_READ) {
609 		result = acpi_ec_read(ec, address, &temp);
610 		*value = temp;
611 	} else {
612 		temp = 0xff & (*value);
613 		result = acpi_ec_write(ec, address, temp);
614 	}
615 
616 	for (i = 8; unlikely(bits - i > 0); i += 8) {
617 		++address;
618 		if (function == ACPI_READ) {
619 			result = acpi_ec_read(ec, address, &temp);
620 			(*value) |= ((acpi_integer)temp) << i;
621 		} else {
622 			temp = 0xff & ((*value) >> i);
623 			result = acpi_ec_write(ec, address, temp);
624 		}
625 	}
626 
627 	acpi_ec_burst_disable(ec);
628 
629 	switch (result) {
630 	case -EINVAL:
631 		return AE_BAD_PARAMETER;
632 		break;
633 	case -ENODEV:
634 		return AE_NOT_FOUND;
635 		break;
636 	case -ETIME:
637 		return AE_TIME;
638 		break;
639 	default:
640 		return AE_OK;
641 	}
642 }
643 
644 /* --------------------------------------------------------------------------
645                               FS Interface (/proc)
646    -------------------------------------------------------------------------- */
647 
648 static struct proc_dir_entry *acpi_ec_dir;
649 
650 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
651 {
652 	struct acpi_ec *ec = seq->private;
653 
654 	if (!ec)
655 		goto end;
656 
657 	seq_printf(seq, "gpe:\t\t\t0x%02x\n", (u32) ec->gpe);
658 	seq_printf(seq, "ports:\t\t\t0x%02x, 0x%02x\n",
659 		   (unsigned)ec->command_addr, (unsigned)ec->data_addr);
660 	seq_printf(seq, "use global lock:\t%s\n",
661 		   ec->global_lock ? "yes" : "no");
662       end:
663 	return 0;
664 }
665 
666 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
667 {
668 	return single_open(file, acpi_ec_read_info, PDE(inode)->data);
669 }
670 
671 static struct file_operations acpi_ec_info_ops = {
672 	.open = acpi_ec_info_open_fs,
673 	.read = seq_read,
674 	.llseek = seq_lseek,
675 	.release = single_release,
676 	.owner = THIS_MODULE,
677 };
678 
679 static int acpi_ec_add_fs(struct acpi_device *device)
680 {
681 	struct proc_dir_entry *entry = NULL;
682 
683 	if (!acpi_device_dir(device)) {
684 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
685 						     acpi_ec_dir);
686 		if (!acpi_device_dir(device))
687 			return -ENODEV;
688 	}
689 
690 	entry = proc_create_data(ACPI_EC_FILE_INFO, S_IRUGO,
691 				 acpi_device_dir(device),
692 				 &acpi_ec_info_ops, acpi_driver_data(device));
693 	if (!entry)
694 		return -ENODEV;
695 	return 0;
696 }
697 
698 static int acpi_ec_remove_fs(struct acpi_device *device)
699 {
700 
701 	if (acpi_device_dir(device)) {
702 		remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
703 		remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
704 		acpi_device_dir(device) = NULL;
705 	}
706 
707 	return 0;
708 }
709 
710 /* --------------------------------------------------------------------------
711                                Driver Interface
712    -------------------------------------------------------------------------- */
713 static acpi_status
714 ec_parse_io_ports(struct acpi_resource *resource, void *context);
715 
716 static struct acpi_ec *make_acpi_ec(void)
717 {
718 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
719 	if (!ec)
720 		return NULL;
721 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
722 	mutex_init(&ec->lock);
723 	init_waitqueue_head(&ec->wait);
724 	INIT_LIST_HEAD(&ec->list);
725 	spin_lock_init(&ec->curr_lock);
726 	return ec;
727 }
728 
729 static acpi_status
730 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
731 			       void *context, void **return_value)
732 {
733 	char node_name[5];
734 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
735 	struct acpi_ec *ec = context;
736 	int value = 0;
737 	acpi_status status;
738 
739 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
740 
741 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
742 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
743 	}
744 	return AE_OK;
745 }
746 
747 static acpi_status
748 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
749 {
750 	acpi_status status;
751 	unsigned long long tmp = 0;
752 
753 	struct acpi_ec *ec = context;
754 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
755 				     ec_parse_io_ports, ec);
756 	if (ACPI_FAILURE(status))
757 		return status;
758 
759 	/* Get GPE bit assignment (EC events). */
760 	/* TODO: Add support for _GPE returning a package */
761 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
762 	if (ACPI_FAILURE(status))
763 		return status;
764 	ec->gpe = tmp;
765 	/* Use the global lock for all EC transactions? */
766 	tmp = 0;
767 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
768 	ec->global_lock = tmp;
769 	ec->handle = handle;
770 	return AE_CTRL_TERMINATE;
771 }
772 
773 static void ec_remove_handlers(struct acpi_ec *ec)
774 {
775 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
776 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
777 		pr_err(PREFIX "failed to remove space handler\n");
778 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
779 				&acpi_ec_gpe_handler)))
780 		pr_err(PREFIX "failed to remove gpe handler\n");
781 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
782 }
783 
784 static int acpi_ec_add(struct acpi_device *device)
785 {
786 	struct acpi_ec *ec = NULL;
787 
788 	if (!device)
789 		return -EINVAL;
790 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
791 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
792 
793 	/* Check for boot EC */
794 	if (boot_ec &&
795 	    (boot_ec->handle == device->handle ||
796 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
797 		ec = boot_ec;
798 		boot_ec = NULL;
799 	} else {
800 		ec = make_acpi_ec();
801 		if (!ec)
802 			return -ENOMEM;
803 		if (ec_parse_device(device->handle, 0, ec, NULL) !=
804 		    AE_CTRL_TERMINATE) {
805 			kfree(ec);
806 			return -EINVAL;
807 		}
808 	}
809 
810 	ec->handle = device->handle;
811 
812 	/* Find and register all query methods */
813 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
814 			    acpi_ec_register_query_methods, ec, NULL);
815 
816 	if (!first_ec)
817 		first_ec = ec;
818 	device->driver_data = ec;
819 	acpi_ec_add_fs(device);
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 	pr_info(PREFIX "driver started in %s mode\n",
823 		(test_bit(EC_FLAGS_GPE_MODE, &ec->flags))?"interrupt":"poll");
824 	return 0;
825 }
826 
827 static int acpi_ec_remove(struct acpi_device *device, int type)
828 {
829 	struct acpi_ec *ec;
830 	struct acpi_ec_query_handler *handler, *tmp;
831 
832 	if (!device)
833 		return -EINVAL;
834 
835 	ec = acpi_driver_data(device);
836 	mutex_lock(&ec->lock);
837 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
838 		list_del(&handler->node);
839 		kfree(handler);
840 	}
841 	mutex_unlock(&ec->lock);
842 	acpi_ec_remove_fs(device);
843 	device->driver_data = NULL;
844 	if (ec == first_ec)
845 		first_ec = NULL;
846 	kfree(ec);
847 	return 0;
848 }
849 
850 static acpi_status
851 ec_parse_io_ports(struct acpi_resource *resource, void *context)
852 {
853 	struct acpi_ec *ec = context;
854 
855 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
856 		return AE_OK;
857 
858 	/*
859 	 * The first address region returned is the data port, and
860 	 * the second address region returned is the status/command
861 	 * port.
862 	 */
863 	if (ec->data_addr == 0)
864 		ec->data_addr = resource->data.io.minimum;
865 	else if (ec->command_addr == 0)
866 		ec->command_addr = resource->data.io.minimum;
867 	else
868 		return AE_CTRL_TERMINATE;
869 
870 	return AE_OK;
871 }
872 
873 static int ec_install_handlers(struct acpi_ec *ec)
874 {
875 	acpi_status status;
876 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
877 		return 0;
878 	status = acpi_install_gpe_handler(NULL, ec->gpe,
879 				  ACPI_GPE_EDGE_TRIGGERED,
880 				  &acpi_ec_gpe_handler, ec);
881 	if (ACPI_FAILURE(status))
882 		return -ENODEV;
883 	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
884 	acpi_enable_gpe(NULL, ec->gpe);
885 	status = acpi_install_address_space_handler(ec->handle,
886 						    ACPI_ADR_SPACE_EC,
887 						    &acpi_ec_space_handler,
888 						    NULL, ec);
889 	if (ACPI_FAILURE(status)) {
890 		if (status == AE_NOT_FOUND) {
891 			/*
892 			 * Maybe OS fails in evaluating the _REG object.
893 			 * The AE_NOT_FOUND error will be ignored and OS
894 			 * continue to initialize EC.
895 			 */
896 			printk(KERN_ERR "Fail in evaluating the _REG object"
897 				" of EC device. Broken bios is suspected.\n");
898 		} else {
899 			acpi_remove_gpe_handler(NULL, ec->gpe,
900 				&acpi_ec_gpe_handler);
901 			return -ENODEV;
902 		}
903 	}
904 
905 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
906 	return 0;
907 }
908 
909 static int acpi_ec_start(struct acpi_device *device)
910 {
911 	struct acpi_ec *ec;
912 	int ret = 0;
913 
914 	if (!device)
915 		return -EINVAL;
916 
917 	ec = acpi_driver_data(device);
918 
919 	if (!ec)
920 		return -EINVAL;
921 
922 	ret = ec_install_handlers(ec);
923 
924 	/* EC is fully operational, allow queries */
925 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
926 	return ret;
927 }
928 
929 static int acpi_ec_stop(struct acpi_device *device, int type)
930 {
931 	struct acpi_ec *ec;
932 	if (!device)
933 		return -EINVAL;
934 	ec = acpi_driver_data(device);
935 	if (!ec)
936 		return -EINVAL;
937 	ec_remove_handlers(ec);
938 
939 	return 0;
940 }
941 
942 int __init acpi_boot_ec_enable(void)
943 {
944 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
945 		return 0;
946 	if (!ec_install_handlers(boot_ec)) {
947 		first_ec = boot_ec;
948 		return 0;
949 	}
950 	return -EFAULT;
951 }
952 
953 static const struct acpi_device_id ec_device_ids[] = {
954 	{"PNP0C09", 0},
955 	{"", 0},
956 };
957 
958 int __init acpi_ec_ecdt_probe(void)
959 {
960 	acpi_status status;
961 	struct acpi_ec *saved_ec = NULL;
962 	struct acpi_table_ecdt *ecdt_ptr;
963 
964 	boot_ec = make_acpi_ec();
965 	if (!boot_ec)
966 		return -ENOMEM;
967 	/*
968 	 * Generate a boot ec context
969 	 */
970 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
971 				(struct acpi_table_header **)&ecdt_ptr);
972 	if (ACPI_SUCCESS(status)) {
973 		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
974 		boot_ec->command_addr = ecdt_ptr->control.address;
975 		boot_ec->data_addr = ecdt_ptr->data.address;
976 		boot_ec->gpe = ecdt_ptr->gpe;
977 		boot_ec->handle = ACPI_ROOT_OBJECT;
978 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
979 		/* Don't trust ECDT, which comes from ASUSTek */
980 		if (!dmi_name_in_vendors("ASUS"))
981 			goto install;
982 		saved_ec = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
983 		if (!saved_ec)
984 			return -ENOMEM;
985 		memcpy(saved_ec, boot_ec, sizeof(*saved_ec));
986 	/* fall through */
987 	}
988 	/* This workaround is needed only on some broken machines,
989 	 * which require early EC, but fail to provide ECDT */
990 	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
991 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
992 					boot_ec, NULL);
993 	/* Check that acpi_get_devices actually find something */
994 	if (ACPI_FAILURE(status) || !boot_ec->handle)
995 		goto error;
996 	if (saved_ec) {
997 		/* try to find good ECDT from ASUSTek */
998 		if (saved_ec->command_addr != boot_ec->command_addr ||
999 		    saved_ec->data_addr != boot_ec->data_addr ||
1000 		    saved_ec->gpe != boot_ec->gpe ||
1001 		    saved_ec->handle != boot_ec->handle)
1002 			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
1003 			"ECDT tables, which are very hard to workaround. "
1004 			"Trying to use DSDT EC info instead. Please send "
1005 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1006 		kfree(saved_ec);
1007 		saved_ec = NULL;
1008 	} else {
1009 		/* We really need to limit this workaround, the only ASUS,
1010 		* which needs it, has fake EC._INI method, so use it as flag.
1011 		* Keep boot_ec struct as it will be needed soon.
1012 		*/
1013 		acpi_handle dummy;
1014 		if (!dmi_name_in_vendors("ASUS") ||
1015 		    ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI",
1016 							&dummy)))
1017 			return -ENODEV;
1018 	}
1019 install:
1020 	if (!ec_install_handlers(boot_ec)) {
1021 		first_ec = boot_ec;
1022 		return 0;
1023 	}
1024 error:
1025 	kfree(boot_ec);
1026 	boot_ec = NULL;
1027 	return -ENODEV;
1028 }
1029 
1030 static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
1031 {
1032 	struct acpi_ec *ec = acpi_driver_data(device);
1033 	/* Stop using GPE */
1034 	set_bit(EC_FLAGS_NO_GPE, &ec->flags);
1035 	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
1036 	acpi_disable_gpe(NULL, ec->gpe);
1037 	return 0;
1038 }
1039 
1040 static int acpi_ec_resume(struct acpi_device *device)
1041 {
1042 	struct acpi_ec *ec = acpi_driver_data(device);
1043 	/* Enable use of GPE back */
1044 	clear_bit(EC_FLAGS_NO_GPE, &ec->flags);
1045 	acpi_enable_gpe(NULL, ec->gpe);
1046 	return 0;
1047 }
1048 
1049 static struct acpi_driver acpi_ec_driver = {
1050 	.name = "ec",
1051 	.class = ACPI_EC_CLASS,
1052 	.ids = ec_device_ids,
1053 	.ops = {
1054 		.add = acpi_ec_add,
1055 		.remove = acpi_ec_remove,
1056 		.start = acpi_ec_start,
1057 		.stop = acpi_ec_stop,
1058 		.suspend = acpi_ec_suspend,
1059 		.resume = acpi_ec_resume,
1060 		},
1061 };
1062 
1063 static int __init acpi_ec_init(void)
1064 {
1065 	int result = 0;
1066 
1067 	if (acpi_disabled)
1068 		return 0;
1069 
1070 	acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
1071 	if (!acpi_ec_dir)
1072 		return -ENODEV;
1073 
1074 	/* Now register the driver for the EC */
1075 	result = acpi_bus_register_driver(&acpi_ec_driver);
1076 	if (result < 0) {
1077 		remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1078 		return -ENODEV;
1079 	}
1080 
1081 	return result;
1082 }
1083 
1084 subsys_initcall(acpi_ec_init);
1085 
1086 /* EC driver currently not unloadable */
1087 #if 0
1088 static void __exit acpi_ec_exit(void)
1089 {
1090 
1091 	acpi_bus_unregister_driver(&acpi_ec_driver);
1092 
1093 	remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1094 
1095 	return;
1096 }
1097 #endif	/* 0 */
1098