xref: /openbmc/linux/drivers/acpi/ec.c (revision b04b4f78)
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_CDELAY		10	/* Wait 10us before polling EC */
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 static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
124 
125 /* --------------------------------------------------------------------------
126                              Transaction Management
127    -------------------------------------------------------------------------- */
128 
129 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
130 {
131 	u8 x = inb(ec->command_addr);
132 	pr_debug(PREFIX "---> status = 0x%2.2x\n", x);
133 	return x;
134 }
135 
136 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
137 {
138 	u8 x = inb(ec->data_addr);
139 	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
140 	return x;
141 }
142 
143 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
144 {
145 	pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
146 	outb(command, ec->command_addr);
147 }
148 
149 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
150 {
151 	pr_debug(PREFIX "<--- data = 0x%2.2x\n", data);
152 	outb(data, ec->data_addr);
153 }
154 
155 static int ec_transaction_done(struct acpi_ec *ec)
156 {
157 	unsigned long flags;
158 	int ret = 0;
159 	spin_lock_irqsave(&ec->curr_lock, flags);
160 	if (!ec->curr || ec->curr->done)
161 		ret = 1;
162 	spin_unlock_irqrestore(&ec->curr_lock, flags);
163 	return ret;
164 }
165 
166 static void start_transaction(struct acpi_ec *ec)
167 {
168 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
169 	ec->curr->done = false;
170 	acpi_ec_write_cmd(ec, ec->curr->command);
171 }
172 
173 static void gpe_transaction(struct acpi_ec *ec, u8 status)
174 {
175 	unsigned long flags;
176 	spin_lock_irqsave(&ec->curr_lock, flags);
177 	if (!ec->curr)
178 		goto unlock;
179 	if (ec->curr->wlen > ec->curr->wi) {
180 		if ((status & ACPI_EC_FLAG_IBF) == 0)
181 			acpi_ec_write_data(ec,
182 				ec->curr->wdata[ec->curr->wi++]);
183 		else
184 			goto err;
185 	} else if (ec->curr->rlen > ec->curr->ri) {
186 		if ((status & ACPI_EC_FLAG_OBF) == 1) {
187 			ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
188 			if (ec->curr->rlen == ec->curr->ri)
189 				ec->curr->done = true;
190 		} else
191 			goto err;
192 	} else if (ec->curr->wlen == ec->curr->wi &&
193 		   (status & ACPI_EC_FLAG_IBF) == 0)
194 		ec->curr->done = true;
195 	goto unlock;
196 err:
197 	/* false interrupt, state didn't change */
198 	if (in_interrupt())
199 		++ec->curr->irq_count;
200 unlock:
201 	spin_unlock_irqrestore(&ec->curr_lock, flags);
202 }
203 
204 static int acpi_ec_wait(struct acpi_ec *ec)
205 {
206 	if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
207 			       msecs_to_jiffies(ACPI_EC_DELAY)))
208 		return 0;
209 	/* try restart command if we get any false interrupts */
210 	if (ec->curr->irq_count &&
211 	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
212 		pr_debug(PREFIX "controller reset, restart transaction\n");
213 		start_transaction(ec);
214 		if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
215 					msecs_to_jiffies(ACPI_EC_DELAY)))
216 			return 0;
217 	}
218 	/* missing GPEs, switch back to poll mode */
219 	if (printk_ratelimit())
220 		pr_info(PREFIX "missing confirmations, "
221 				"switch off interrupt mode.\n");
222 	set_bit(EC_FLAGS_NO_GPE, &ec->flags);
223 	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
224 	return 1;
225 }
226 
227 static void acpi_ec_gpe_query(void *ec_cxt);
228 
229 static int ec_check_sci(struct acpi_ec *ec, u8 state)
230 {
231 	if (state & ACPI_EC_FLAG_SCI) {
232 		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
233 			return acpi_os_execute(OSL_EC_BURST_HANDLER,
234 				acpi_ec_gpe_query, ec);
235 	}
236 	return 0;
237 }
238 
239 static void ec_delay(void)
240 {
241 	/* EC in MSI notebooks don't tolerate delays other than 550 usec */
242 	if (EC_FLAGS_MSI)
243 		udelay(ACPI_EC_DELAY);
244 	else
245 		/* Use shortest sleep available */
246 		msleep(1);
247 }
248 
249 static int ec_poll(struct acpi_ec *ec)
250 {
251 	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
252 	udelay(ACPI_EC_CDELAY);
253 	while (time_before(jiffies, delay)) {
254 		gpe_transaction(ec, acpi_ec_read_status(ec));
255 		ec_delay();
256 		if (ec_transaction_done(ec))
257 			return 0;
258 	}
259 	return -ETIME;
260 }
261 
262 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
263 					struct transaction *t,
264 					int force_poll)
265 {
266 	unsigned long tmp;
267 	int ret = 0;
268 	pr_debug(PREFIX "transaction start\n");
269 	/* disable GPE during transaction if storm is detected */
270 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
271 		clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
272 		acpi_disable_gpe(NULL, ec->gpe);
273 	}
274 	if (EC_FLAGS_MSI)
275 		udelay(ACPI_EC_DELAY);
276 	/* start transaction */
277 	spin_lock_irqsave(&ec->curr_lock, tmp);
278 	/* following two actions should be kept atomic */
279 	ec->curr = t;
280 	start_transaction(ec);
281 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
282 		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
283 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
284 	/* if we selected poll mode or failed in GPE-mode do a poll loop */
285 	if (force_poll ||
286 	    !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||
287 	    acpi_ec_wait(ec))
288 		ret = ec_poll(ec);
289 	pr_debug(PREFIX "transaction end\n");
290 	spin_lock_irqsave(&ec->curr_lock, tmp);
291 	ec->curr = NULL;
292 	spin_unlock_irqrestore(&ec->curr_lock, tmp);
293 	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
294 		/* check if we received SCI during transaction */
295 		ec_check_sci(ec, acpi_ec_read_status(ec));
296 		/* it is safe to enable GPE outside of transaction */
297 		acpi_enable_gpe(NULL, ec->gpe);
298 	} else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
299 		   t->irq_count > ACPI_EC_STORM_THRESHOLD) {
300 		pr_info(PREFIX "GPE storm detected, "
301 			"transactions will use polling mode\n");
302 		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
303 	}
304 	return ret;
305 }
306 
307 static int ec_check_ibf0(struct acpi_ec *ec)
308 {
309 	u8 status = acpi_ec_read_status(ec);
310 	return (status & ACPI_EC_FLAG_IBF) == 0;
311 }
312 
313 static int ec_wait_ibf0(struct acpi_ec *ec)
314 {
315 	unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
316 	/* interrupt wait manually if GPE mode is not active */
317 	unsigned long timeout = test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ?
318 		msecs_to_jiffies(ACPI_EC_DELAY) : msecs_to_jiffies(1);
319 	while (time_before(jiffies, delay))
320 		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec), timeout))
321 			return 0;
322 	return -ETIME;
323 }
324 
325 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t,
326 			       int force_poll)
327 {
328 	int status;
329 	u32 glk;
330 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
331 		return -EINVAL;
332 	if (t->rdata)
333 		memset(t->rdata, 0, t->rlen);
334 	mutex_lock(&ec->lock);
335 	if (ec->global_lock) {
336 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
337 		if (ACPI_FAILURE(status)) {
338 			status = -ENODEV;
339 			goto unlock;
340 		}
341 	}
342 	if (ec_wait_ibf0(ec)) {
343 		pr_err(PREFIX "input buffer is not empty, "
344 				"aborting transaction\n");
345 		status = -ETIME;
346 		goto end;
347 	}
348 	status = acpi_ec_transaction_unlocked(ec, t, force_poll);
349 end:
350 	if (ec->global_lock)
351 		acpi_release_global_lock(glk);
352 unlock:
353 	mutex_unlock(&ec->lock);
354 	return status;
355 }
356 
357 /*
358  * Note: samsung nv5000 doesn't work with ec burst mode.
359  * http://bugzilla.kernel.org/show_bug.cgi?id=4980
360  */
361 static int acpi_ec_burst_enable(struct acpi_ec *ec)
362 {
363 	u8 d;
364 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
365 				.wdata = NULL, .rdata = &d,
366 				.wlen = 0, .rlen = 1};
367 
368 	return acpi_ec_transaction(ec, &t, 0);
369 }
370 
371 static int acpi_ec_burst_disable(struct acpi_ec *ec)
372 {
373 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
374 				.wdata = NULL, .rdata = NULL,
375 				.wlen = 0, .rlen = 0};
376 
377 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
378 				acpi_ec_transaction(ec, &t, 0) : 0;
379 }
380 
381 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
382 {
383 	int result;
384 	u8 d;
385 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
386 				.wdata = &address, .rdata = &d,
387 				.wlen = 1, .rlen = 1};
388 
389 	result = acpi_ec_transaction(ec, &t, 0);
390 	*data = d;
391 	return result;
392 }
393 
394 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
395 {
396 	u8 wdata[2] = { address, data };
397 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
398 				.wdata = wdata, .rdata = NULL,
399 				.wlen = 2, .rlen = 0};
400 
401 	return acpi_ec_transaction(ec, &t, 0);
402 }
403 
404 /*
405  * Externally callable EC access functions. For now, assume 1 EC only
406  */
407 int ec_burst_enable(void)
408 {
409 	if (!first_ec)
410 		return -ENODEV;
411 	return acpi_ec_burst_enable(first_ec);
412 }
413 
414 EXPORT_SYMBOL(ec_burst_enable);
415 
416 int ec_burst_disable(void)
417 {
418 	if (!first_ec)
419 		return -ENODEV;
420 	return acpi_ec_burst_disable(first_ec);
421 }
422 
423 EXPORT_SYMBOL(ec_burst_disable);
424 
425 int ec_read(u8 addr, u8 * val)
426 {
427 	int err;
428 	u8 temp_data;
429 
430 	if (!first_ec)
431 		return -ENODEV;
432 
433 	err = acpi_ec_read(first_ec, addr, &temp_data);
434 
435 	if (!err) {
436 		*val = temp_data;
437 		return 0;
438 	} else
439 		return err;
440 }
441 
442 EXPORT_SYMBOL(ec_read);
443 
444 int ec_write(u8 addr, u8 val)
445 {
446 	int err;
447 
448 	if (!first_ec)
449 		return -ENODEV;
450 
451 	err = acpi_ec_write(first_ec, addr, val);
452 
453 	return err;
454 }
455 
456 EXPORT_SYMBOL(ec_write);
457 
458 int ec_transaction(u8 command,
459 		   const u8 * wdata, unsigned wdata_len,
460 		   u8 * rdata, unsigned rdata_len,
461 		   int force_poll)
462 {
463 	struct transaction t = {.command = command,
464 				.wdata = wdata, .rdata = rdata,
465 				.wlen = wdata_len, .rlen = rdata_len};
466 	if (!first_ec)
467 		return -ENODEV;
468 
469 	return acpi_ec_transaction(first_ec, &t, force_poll);
470 }
471 
472 EXPORT_SYMBOL(ec_transaction);
473 
474 static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
475 {
476 	int result;
477 	u8 d;
478 	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
479 				.wdata = NULL, .rdata = &d,
480 				.wlen = 0, .rlen = 1};
481 	if (!ec || !data)
482 		return -EINVAL;
483 
484 	/*
485 	 * Query the EC to find out which _Qxx method we need to evaluate.
486 	 * Note that successful completion of the query causes the ACPI_EC_SCI
487 	 * bit to be cleared (and thus clearing the interrupt source).
488 	 */
489 
490 	result = acpi_ec_transaction(ec, &t, 0);
491 	if (result)
492 		return result;
493 
494 	if (!d)
495 		return -ENODATA;
496 
497 	*data = d;
498 	return 0;
499 }
500 
501 /* --------------------------------------------------------------------------
502                                 Event Management
503    -------------------------------------------------------------------------- */
504 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
505 			      acpi_handle handle, acpi_ec_query_func func,
506 			      void *data)
507 {
508 	struct acpi_ec_query_handler *handler =
509 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
510 	if (!handler)
511 		return -ENOMEM;
512 
513 	handler->query_bit = query_bit;
514 	handler->handle = handle;
515 	handler->func = func;
516 	handler->data = data;
517 	mutex_lock(&ec->lock);
518 	list_add(&handler->node, &ec->list);
519 	mutex_unlock(&ec->lock);
520 	return 0;
521 }
522 
523 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
524 
525 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
526 {
527 	struct acpi_ec_query_handler *handler, *tmp;
528 	mutex_lock(&ec->lock);
529 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
530 		if (query_bit == handler->query_bit) {
531 			list_del(&handler->node);
532 			kfree(handler);
533 		}
534 	}
535 	mutex_unlock(&ec->lock);
536 }
537 
538 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
539 
540 static void acpi_ec_gpe_query(void *ec_cxt)
541 {
542 	struct acpi_ec *ec = ec_cxt;
543 	u8 value = 0;
544 	struct acpi_ec_query_handler *handler, copy;
545 
546 	if (!ec || acpi_ec_query(ec, &value))
547 		return;
548 	mutex_lock(&ec->lock);
549 	list_for_each_entry(handler, &ec->list, node) {
550 		if (value == handler->query_bit) {
551 			/* have custom handler for this bit */
552 			memcpy(&copy, handler, sizeof(copy));
553 			mutex_unlock(&ec->lock);
554 			if (copy.func) {
555 				copy.func(copy.data);
556 			} else if (copy.handle) {
557 				acpi_evaluate_object(copy.handle, NULL, NULL, NULL);
558 			}
559 			return;
560 		}
561 	}
562 	mutex_unlock(&ec->lock);
563 }
564 
565 static u32 acpi_ec_gpe_handler(void *data)
566 {
567 	struct acpi_ec *ec = data;
568 	u8 status;
569 
570 	pr_debug(PREFIX "~~~> interrupt\n");
571 	status = acpi_ec_read_status(ec);
572 
573 	if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) {
574 		gpe_transaction(ec, status);
575 		if (ec_transaction_done(ec) &&
576 		    (status & ACPI_EC_FLAG_IBF) == 0)
577 			wake_up(&ec->wait);
578 	}
579 
580 	ec_check_sci(ec, status);
581 	if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
582 	    !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) {
583 		/* this is non-query, must be confirmation */
584 		if (!test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
585 			if (printk_ratelimit())
586 				pr_info(PREFIX "non-query interrupt received,"
587 					" switching to interrupt mode\n");
588 		} else {
589 			/* hush, STORM switches the mode every transaction */
590 			pr_debug(PREFIX "non-query interrupt received,"
591 				" switching to interrupt mode\n");
592 		}
593 		set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
594 	}
595 	return ACPI_INTERRUPT_HANDLED;
596 }
597 
598 /* --------------------------------------------------------------------------
599                              Address Space Management
600    -------------------------------------------------------------------------- */
601 
602 static acpi_status
603 acpi_ec_space_handler(u32 function, acpi_physical_address address,
604 		      u32 bits, acpi_integer *value,
605 		      void *handler_context, void *region_context)
606 {
607 	struct acpi_ec *ec = handler_context;
608 	int result = 0, i;
609 	u8 temp = 0;
610 
611 	if ((address > 0xFF) || !value || !handler_context)
612 		return AE_BAD_PARAMETER;
613 
614 	if (function != ACPI_READ && function != ACPI_WRITE)
615 		return AE_BAD_PARAMETER;
616 
617 	if (bits != 8 && acpi_strict)
618 		return AE_BAD_PARAMETER;
619 
620 	acpi_ec_burst_enable(ec);
621 
622 	if (function == ACPI_READ) {
623 		result = acpi_ec_read(ec, address, &temp);
624 		*value = temp;
625 	} else {
626 		temp = 0xff & (*value);
627 		result = acpi_ec_write(ec, address, temp);
628 	}
629 
630 	for (i = 8; unlikely(bits - i > 0); i += 8) {
631 		++address;
632 		if (function == ACPI_READ) {
633 			result = acpi_ec_read(ec, address, &temp);
634 			(*value) |= ((acpi_integer)temp) << i;
635 		} else {
636 			temp = 0xff & ((*value) >> i);
637 			result = acpi_ec_write(ec, address, temp);
638 		}
639 	}
640 
641 	acpi_ec_burst_disable(ec);
642 
643 	switch (result) {
644 	case -EINVAL:
645 		return AE_BAD_PARAMETER;
646 		break;
647 	case -ENODEV:
648 		return AE_NOT_FOUND;
649 		break;
650 	case -ETIME:
651 		return AE_TIME;
652 		break;
653 	default:
654 		return AE_OK;
655 	}
656 }
657 
658 /* --------------------------------------------------------------------------
659                               FS Interface (/proc)
660    -------------------------------------------------------------------------- */
661 
662 static struct proc_dir_entry *acpi_ec_dir;
663 
664 static int acpi_ec_read_info(struct seq_file *seq, void *offset)
665 {
666 	struct acpi_ec *ec = seq->private;
667 
668 	if (!ec)
669 		goto end;
670 
671 	seq_printf(seq, "gpe:\t\t\t0x%02x\n", (u32) ec->gpe);
672 	seq_printf(seq, "ports:\t\t\t0x%02x, 0x%02x\n",
673 		   (unsigned)ec->command_addr, (unsigned)ec->data_addr);
674 	seq_printf(seq, "use global lock:\t%s\n",
675 		   ec->global_lock ? "yes" : "no");
676       end:
677 	return 0;
678 }
679 
680 static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
681 {
682 	return single_open(file, acpi_ec_read_info, PDE(inode)->data);
683 }
684 
685 static const struct file_operations acpi_ec_info_ops = {
686 	.open = acpi_ec_info_open_fs,
687 	.read = seq_read,
688 	.llseek = seq_lseek,
689 	.release = single_release,
690 	.owner = THIS_MODULE,
691 };
692 
693 static int acpi_ec_add_fs(struct acpi_device *device)
694 {
695 	struct proc_dir_entry *entry = NULL;
696 
697 	if (!acpi_device_dir(device)) {
698 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
699 						     acpi_ec_dir);
700 		if (!acpi_device_dir(device))
701 			return -ENODEV;
702 	}
703 
704 	entry = proc_create_data(ACPI_EC_FILE_INFO, S_IRUGO,
705 				 acpi_device_dir(device),
706 				 &acpi_ec_info_ops, acpi_driver_data(device));
707 	if (!entry)
708 		return -ENODEV;
709 	return 0;
710 }
711 
712 static int acpi_ec_remove_fs(struct acpi_device *device)
713 {
714 
715 	if (acpi_device_dir(device)) {
716 		remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
717 		remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
718 		acpi_device_dir(device) = NULL;
719 	}
720 
721 	return 0;
722 }
723 
724 /* --------------------------------------------------------------------------
725                                Driver Interface
726    -------------------------------------------------------------------------- */
727 static acpi_status
728 ec_parse_io_ports(struct acpi_resource *resource, void *context);
729 
730 static struct acpi_ec *make_acpi_ec(void)
731 {
732 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
733 	if (!ec)
734 		return NULL;
735 	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
736 	mutex_init(&ec->lock);
737 	init_waitqueue_head(&ec->wait);
738 	INIT_LIST_HEAD(&ec->list);
739 	spin_lock_init(&ec->curr_lock);
740 	return ec;
741 }
742 
743 static acpi_status
744 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
745 			       void *context, void **return_value)
746 {
747 	char node_name[5];
748 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
749 	struct acpi_ec *ec = context;
750 	int value = 0;
751 	acpi_status status;
752 
753 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
754 
755 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
756 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
757 	}
758 	return AE_OK;
759 }
760 
761 static acpi_status
762 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
763 {
764 	acpi_status status;
765 	unsigned long long tmp = 0;
766 
767 	struct acpi_ec *ec = context;
768 
769 	/* clear addr values, ec_parse_io_ports depend on it */
770 	ec->command_addr = ec->data_addr = 0;
771 
772 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
773 				     ec_parse_io_ports, ec);
774 	if (ACPI_FAILURE(status))
775 		return status;
776 
777 	/* Get GPE bit assignment (EC events). */
778 	/* TODO: Add support for _GPE returning a package */
779 	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
780 	if (ACPI_FAILURE(status))
781 		return status;
782 	ec->gpe = tmp;
783 	/* Use the global lock for all EC transactions? */
784 	tmp = 0;
785 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
786 	ec->global_lock = tmp;
787 	ec->handle = handle;
788 	return AE_CTRL_TERMINATE;
789 }
790 
791 static void ec_remove_handlers(struct acpi_ec *ec)
792 {
793 	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
794 				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
795 		pr_err(PREFIX "failed to remove space handler\n");
796 	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
797 				&acpi_ec_gpe_handler)))
798 		pr_err(PREFIX "failed to remove gpe handler\n");
799 	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
800 }
801 
802 static int acpi_ec_add(struct acpi_device *device)
803 {
804 	struct acpi_ec *ec = NULL;
805 
806 	if (!device)
807 		return -EINVAL;
808 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
809 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
810 
811 	/* Check for boot EC */
812 	if (boot_ec &&
813 	    (boot_ec->handle == device->handle ||
814 	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
815 		ec = boot_ec;
816 		boot_ec = NULL;
817 	} else {
818 		ec = make_acpi_ec();
819 		if (!ec)
820 			return -ENOMEM;
821 	}
822 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
823 		AE_CTRL_TERMINATE) {
824 			kfree(ec);
825 			return -EINVAL;
826 	}
827 
828 	ec->handle = device->handle;
829 
830 	/* Find and register all query methods */
831 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
832 			    acpi_ec_register_query_methods, ec, NULL);
833 
834 	if (!first_ec)
835 		first_ec = ec;
836 	device->driver_data = ec;
837 	acpi_ec_add_fs(device);
838 	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
839 			  ec->gpe, ec->command_addr, ec->data_addr);
840 	pr_info(PREFIX "driver started in %s mode\n",
841 		(test_bit(EC_FLAGS_GPE_MODE, &ec->flags))?"interrupt":"poll");
842 	return 0;
843 }
844 
845 static int acpi_ec_remove(struct acpi_device *device, int type)
846 {
847 	struct acpi_ec *ec;
848 	struct acpi_ec_query_handler *handler, *tmp;
849 
850 	if (!device)
851 		return -EINVAL;
852 
853 	ec = acpi_driver_data(device);
854 	mutex_lock(&ec->lock);
855 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
856 		list_del(&handler->node);
857 		kfree(handler);
858 	}
859 	mutex_unlock(&ec->lock);
860 	acpi_ec_remove_fs(device);
861 	device->driver_data = NULL;
862 	if (ec == first_ec)
863 		first_ec = NULL;
864 	kfree(ec);
865 	return 0;
866 }
867 
868 static acpi_status
869 ec_parse_io_ports(struct acpi_resource *resource, void *context)
870 {
871 	struct acpi_ec *ec = context;
872 
873 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
874 		return AE_OK;
875 
876 	/*
877 	 * The first address region returned is the data port, and
878 	 * the second address region returned is the status/command
879 	 * port.
880 	 */
881 	if (ec->data_addr == 0)
882 		ec->data_addr = resource->data.io.minimum;
883 	else if (ec->command_addr == 0)
884 		ec->command_addr = resource->data.io.minimum;
885 	else
886 		return AE_CTRL_TERMINATE;
887 
888 	return AE_OK;
889 }
890 
891 static int ec_install_handlers(struct acpi_ec *ec)
892 {
893 	acpi_status status;
894 	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
895 		return 0;
896 	status = acpi_install_gpe_handler(NULL, ec->gpe,
897 				  ACPI_GPE_EDGE_TRIGGERED,
898 				  &acpi_ec_gpe_handler, ec);
899 	if (ACPI_FAILURE(status))
900 		return -ENODEV;
901 	acpi_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
902 	acpi_enable_gpe(NULL, ec->gpe);
903 	status = acpi_install_address_space_handler(ec->handle,
904 						    ACPI_ADR_SPACE_EC,
905 						    &acpi_ec_space_handler,
906 						    NULL, ec);
907 	if (ACPI_FAILURE(status)) {
908 		if (status == AE_NOT_FOUND) {
909 			/*
910 			 * Maybe OS fails in evaluating the _REG object.
911 			 * The AE_NOT_FOUND error will be ignored and OS
912 			 * continue to initialize EC.
913 			 */
914 			printk(KERN_ERR "Fail in evaluating the _REG object"
915 				" of EC device. Broken bios is suspected.\n");
916 		} else {
917 			acpi_remove_gpe_handler(NULL, ec->gpe,
918 				&acpi_ec_gpe_handler);
919 			return -ENODEV;
920 		}
921 	}
922 
923 	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
924 	return 0;
925 }
926 
927 static int acpi_ec_start(struct acpi_device *device)
928 {
929 	struct acpi_ec *ec;
930 	int ret = 0;
931 
932 	if (!device)
933 		return -EINVAL;
934 
935 	ec = acpi_driver_data(device);
936 
937 	if (!ec)
938 		return -EINVAL;
939 
940 	ret = ec_install_handlers(ec);
941 
942 	/* EC is fully operational, allow queries */
943 	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
944 	return ret;
945 }
946 
947 static int acpi_ec_stop(struct acpi_device *device, int type)
948 {
949 	struct acpi_ec *ec;
950 	if (!device)
951 		return -EINVAL;
952 	ec = acpi_driver_data(device);
953 	if (!ec)
954 		return -EINVAL;
955 	ec_remove_handlers(ec);
956 
957 	return 0;
958 }
959 
960 int __init acpi_boot_ec_enable(void)
961 {
962 	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
963 		return 0;
964 	if (!ec_install_handlers(boot_ec)) {
965 		first_ec = boot_ec;
966 		return 0;
967 	}
968 	return -EFAULT;
969 }
970 
971 static const struct acpi_device_id ec_device_ids[] = {
972 	{"PNP0C09", 0},
973 	{"", 0},
974 };
975 
976 int __init acpi_ec_ecdt_probe(void)
977 {
978 	acpi_status status;
979 	struct acpi_ec *saved_ec = NULL;
980 	struct acpi_table_ecdt *ecdt_ptr;
981 
982 	boot_ec = make_acpi_ec();
983 	if (!boot_ec)
984 		return -ENOMEM;
985 	/*
986 	 * Generate a boot ec context
987 	 */
988 	if (dmi_name_in_vendors("Micro-Star") ||
989 	    dmi_name_in_vendors("Notebook")) {
990 		pr_info(PREFIX "Enabling special treatment for EC from MSI.\n");
991 		EC_FLAGS_MSI = 1;
992 	}
993 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
994 				(struct acpi_table_header **)&ecdt_ptr);
995 	if (ACPI_SUCCESS(status)) {
996 		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
997 		boot_ec->command_addr = ecdt_ptr->control.address;
998 		boot_ec->data_addr = ecdt_ptr->data.address;
999 		boot_ec->gpe = ecdt_ptr->gpe;
1000 		boot_ec->handle = ACPI_ROOT_OBJECT;
1001 		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
1002 		/* Don't trust ECDT, which comes from ASUSTek */
1003 		if (!dmi_name_in_vendors("ASUS") && EC_FLAGS_MSI == 0)
1004 			goto install;
1005 		saved_ec = kmalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1006 		if (!saved_ec)
1007 			return -ENOMEM;
1008 		memcpy(saved_ec, boot_ec, sizeof(struct acpi_ec));
1009 	/* fall through */
1010 	}
1011 	/* This workaround is needed only on some broken machines,
1012 	 * which require early EC, but fail to provide ECDT */
1013 	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
1014 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
1015 					boot_ec, NULL);
1016 	/* Check that acpi_get_devices actually find something */
1017 	if (ACPI_FAILURE(status) || !boot_ec->handle)
1018 		goto error;
1019 	if (saved_ec) {
1020 		/* try to find good ECDT from ASUSTek */
1021 		if (saved_ec->command_addr != boot_ec->command_addr ||
1022 		    saved_ec->data_addr != boot_ec->data_addr ||
1023 		    saved_ec->gpe != boot_ec->gpe ||
1024 		    saved_ec->handle != boot_ec->handle)
1025 			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
1026 			"ECDT tables, which are very hard to workaround. "
1027 			"Trying to use DSDT EC info instead. Please send "
1028 			"output of acpidump to linux-acpi@vger.kernel.org\n");
1029 		kfree(saved_ec);
1030 		saved_ec = NULL;
1031 	} else {
1032 		/* We really need to limit this workaround, the only ASUS,
1033 		* which needs it, has fake EC._INI method, so use it as flag.
1034 		* Keep boot_ec struct as it will be needed soon.
1035 		*/
1036 		acpi_handle dummy;
1037 		if (!dmi_name_in_vendors("ASUS") ||
1038 		    ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI",
1039 							&dummy)))
1040 			return -ENODEV;
1041 	}
1042 install:
1043 	if (!ec_install_handlers(boot_ec)) {
1044 		first_ec = boot_ec;
1045 		return 0;
1046 	}
1047 error:
1048 	kfree(boot_ec);
1049 	boot_ec = NULL;
1050 	return -ENODEV;
1051 }
1052 
1053 static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
1054 {
1055 	struct acpi_ec *ec = acpi_driver_data(device);
1056 	/* Stop using GPE */
1057 	set_bit(EC_FLAGS_NO_GPE, &ec->flags);
1058 	clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
1059 	acpi_disable_gpe(NULL, ec->gpe);
1060 	return 0;
1061 }
1062 
1063 static int acpi_ec_resume(struct acpi_device *device)
1064 {
1065 	struct acpi_ec *ec = acpi_driver_data(device);
1066 	/* Enable use of GPE back */
1067 	clear_bit(EC_FLAGS_NO_GPE, &ec->flags);
1068 	set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
1069 	acpi_enable_gpe(NULL, ec->gpe);
1070 	return 0;
1071 }
1072 
1073 static struct acpi_driver acpi_ec_driver = {
1074 	.name = "ec",
1075 	.class = ACPI_EC_CLASS,
1076 	.ids = ec_device_ids,
1077 	.ops = {
1078 		.add = acpi_ec_add,
1079 		.remove = acpi_ec_remove,
1080 		.start = acpi_ec_start,
1081 		.stop = acpi_ec_stop,
1082 		.suspend = acpi_ec_suspend,
1083 		.resume = acpi_ec_resume,
1084 		},
1085 };
1086 
1087 int __init acpi_ec_init(void)
1088 {
1089 	int result = 0;
1090 
1091 	acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
1092 	if (!acpi_ec_dir)
1093 		return -ENODEV;
1094 
1095 	/* Now register the driver for the EC */
1096 	result = acpi_bus_register_driver(&acpi_ec_driver);
1097 	if (result < 0) {
1098 		remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1099 		return -ENODEV;
1100 	}
1101 
1102 	return result;
1103 }
1104 
1105 /* EC driver currently not unloadable */
1106 #if 0
1107 static void __exit acpi_ec_exit(void)
1108 {
1109 
1110 	acpi_bus_unregister_driver(&acpi_ec_driver);
1111 
1112 	remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
1113 
1114 	return;
1115 }
1116 #endif	/* 0 */
1117