xref: /openbmc/linux/drivers/acpi/ec.c (revision d9fd5a71)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ec.c - ACPI Embedded Controller Driver (v3)
4  *
5  *  Copyright (C) 2001-2015 Intel Corporation
6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
9  *            2004       Luming Yu <luming.yu@intel.com>
10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
13  */
14 
15 /* Uncomment next line to get verbose printout */
16 /* #define DEBUG */
17 #define pr_fmt(fmt) "ACPI: EC: " fmt
18 
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
22 #include <linux/types.h>
23 #include <linux/delay.h>
24 #include <linux/interrupt.h>
25 #include <linux/list.h>
26 #include <linux/spinlock.h>
27 #include <linux/slab.h>
28 #include <linux/suspend.h>
29 #include <linux/acpi.h>
30 #include <linux/dmi.h>
31 #include <asm/io.h>
32 
33 #include "internal.h"
34 
35 #define ACPI_EC_CLASS			"embedded_controller"
36 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
37 
38 /* EC status register */
39 #define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
40 #define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
41 #define ACPI_EC_FLAG_CMD	0x08	/* Input buffer contains a command */
42 #define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
43 #define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */
44 
45 /*
46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
47  * This leads to lots of practical timing issues for the host EC driver.
48  * The following variations are defined (from the target EC firmware's
49  * perspective):
50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
51  *         target can clear SCI_EVT at any time so long as the host can see
52  *         the indication by reading the status register (EC_SC). So the
53  *         host should re-check SCI_EVT after the first time the SCI_EVT
54  *         indication is seen, which is the same time the query request
55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
56  *         at any later time could indicate another event. Normally such
57  *         kind of EC firmware has implemented an event queue and will
58  *         return 0x00 to indicate "no outstanding event".
59  * QUERY: After seeing the query request (QR_EC) written to the command
60  *        register (EC_CMD) by the host and having prepared the responding
61  *        event value in the data register (EC_DATA), the target can safely
62  *        clear SCI_EVT because the target can confirm that the current
63  *        event is being handled by the host. The host then should check
64  *        SCI_EVT right after reading the event response from the data
65  *        register (EC_DATA).
66  * EVENT: After seeing the event response read from the data register
67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
68  *        target requires time to notice the change in the data register
69  *        (EC_DATA), the host may be required to wait additional guarding
70  *        time before checking the SCI_EVT again. Such guarding may not be
71  *        necessary if the host is notified via another IRQ.
72  */
73 #define ACPI_EC_EVT_TIMING_STATUS	0x00
74 #define ACPI_EC_EVT_TIMING_QUERY	0x01
75 #define ACPI_EC_EVT_TIMING_EVENT	0x02
76 
77 /* EC commands */
78 enum ec_command {
79 	ACPI_EC_COMMAND_READ = 0x80,
80 	ACPI_EC_COMMAND_WRITE = 0x81,
81 	ACPI_EC_BURST_ENABLE = 0x82,
82 	ACPI_EC_BURST_DISABLE = 0x83,
83 	ACPI_EC_COMMAND_QUERY = 0x84,
84 };
85 
86 #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
87 #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
88 #define ACPI_EC_UDELAY_POLL	550	/* Wait 1ms for EC transaction polling */
89 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
90 					 * when trying to clear the EC */
91 #define ACPI_EC_MAX_QUERIES	16	/* Maximum number of parallel queries */
92 
93 enum {
94 	EC_FLAGS_QUERY_ENABLED,		/* Query is enabled */
95 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
96 	EC_FLAGS_QUERY_GUARDING,	/* Guard for SCI_EVT check */
97 	EC_FLAGS_EVENT_HANDLER_INSTALLED,	/* Event handler installed */
98 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
99 	EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
100 	EC_FLAGS_STARTED,		/* Driver is started */
101 	EC_FLAGS_STOPPED,		/* Driver is stopped */
102 	EC_FLAGS_EVENTS_MASKED,		/* Events masked */
103 };
104 
105 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
106 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
107 
108 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
109 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
110 module_param(ec_delay, uint, 0644);
111 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
112 
113 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
114 module_param(ec_max_queries, uint, 0644);
115 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
116 
117 static bool ec_busy_polling __read_mostly;
118 module_param(ec_busy_polling, bool, 0644);
119 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
120 
121 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
122 module_param(ec_polling_guard, uint, 0644);
123 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
124 
125 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
126 
127 /*
128  * If the number of false interrupts per one transaction exceeds
129  * this threshold, will think there is a GPE storm happened and
130  * will disable the GPE for normal transaction.
131  */
132 static unsigned int ec_storm_threshold  __read_mostly = 8;
133 module_param(ec_storm_threshold, uint, 0644);
134 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
135 
136 static bool ec_freeze_events __read_mostly = false;
137 module_param(ec_freeze_events, bool, 0644);
138 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
139 
140 static bool ec_no_wakeup __read_mostly;
141 module_param(ec_no_wakeup, bool, 0644);
142 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
143 
144 struct acpi_ec_query_handler {
145 	struct list_head node;
146 	acpi_ec_query_func func;
147 	acpi_handle handle;
148 	void *data;
149 	u8 query_bit;
150 	struct kref kref;
151 };
152 
153 struct transaction {
154 	const u8 *wdata;
155 	u8 *rdata;
156 	unsigned short irq_count;
157 	u8 command;
158 	u8 wi;
159 	u8 ri;
160 	u8 wlen;
161 	u8 rlen;
162 	u8 flags;
163 };
164 
165 struct acpi_ec_query {
166 	struct transaction transaction;
167 	struct work_struct work;
168 	struct acpi_ec_query_handler *handler;
169 };
170 
171 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
172 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
173 static void acpi_ec_event_handler(struct work_struct *work);
174 static void acpi_ec_event_processor(struct work_struct *work);
175 
176 struct acpi_ec *first_ec;
177 EXPORT_SYMBOL(first_ec);
178 
179 static struct acpi_ec *boot_ec;
180 static bool boot_ec_is_ecdt = false;
181 static struct workqueue_struct *ec_wq;
182 static struct workqueue_struct *ec_query_wq;
183 
184 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
185 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
186 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
187 
188 /* --------------------------------------------------------------------------
189  *                           Logging/Debugging
190  * -------------------------------------------------------------------------- */
191 
192 /*
193  * Splitters used by the developers to track the boundary of the EC
194  * handling processes.
195  */
196 #ifdef DEBUG
197 #define EC_DBG_SEP	" "
198 #define EC_DBG_DRV	"+++++"
199 #define EC_DBG_STM	"====="
200 #define EC_DBG_REQ	"*****"
201 #define EC_DBG_EVT	"#####"
202 #else
203 #define EC_DBG_SEP	""
204 #define EC_DBG_DRV
205 #define EC_DBG_STM
206 #define EC_DBG_REQ
207 #define EC_DBG_EVT
208 #endif
209 
210 #define ec_log_raw(fmt, ...) \
211 	pr_info(fmt "\n", ##__VA_ARGS__)
212 #define ec_dbg_raw(fmt, ...) \
213 	pr_debug(fmt "\n", ##__VA_ARGS__)
214 #define ec_log(filter, fmt, ...) \
215 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
216 #define ec_dbg(filter, fmt, ...) \
217 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
218 
219 #define ec_log_drv(fmt, ...) \
220 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
221 #define ec_dbg_drv(fmt, ...) \
222 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
223 #define ec_dbg_stm(fmt, ...) \
224 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
225 #define ec_dbg_req(fmt, ...) \
226 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
227 #define ec_dbg_evt(fmt, ...) \
228 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
229 #define ec_dbg_ref(ec, fmt, ...) \
230 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
231 
232 /* --------------------------------------------------------------------------
233  *                           Device Flags
234  * -------------------------------------------------------------------------- */
235 
236 static bool acpi_ec_started(struct acpi_ec *ec)
237 {
238 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
239 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
240 }
241 
242 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
243 {
244 	/*
245 	 * There is an OSPM early stage logic. During the early stages
246 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
247 	 * the EC transactions are allowed to be performed.
248 	 */
249 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
250 		return false;
251 	/*
252 	 * However, disabling the event handling is experimental for late
253 	 * stage (suspend), and is controlled by the boot parameter of
254 	 * "ec_freeze_events":
255 	 * 1. true:  The EC event handling is disabled before entering
256 	 *           the noirq stage.
257 	 * 2. false: The EC event handling is automatically disabled as
258 	 *           soon as the EC driver is stopped.
259 	 */
260 	if (ec_freeze_events)
261 		return acpi_ec_started(ec);
262 	else
263 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
264 }
265 
266 static bool acpi_ec_flushed(struct acpi_ec *ec)
267 {
268 	return ec->reference_count == 1;
269 }
270 
271 /* --------------------------------------------------------------------------
272  *                           EC Registers
273  * -------------------------------------------------------------------------- */
274 
275 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
276 {
277 	u8 x = inb(ec->command_addr);
278 
279 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
280 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
281 		   x,
282 		   !!(x & ACPI_EC_FLAG_SCI),
283 		   !!(x & ACPI_EC_FLAG_BURST),
284 		   !!(x & ACPI_EC_FLAG_CMD),
285 		   !!(x & ACPI_EC_FLAG_IBF),
286 		   !!(x & ACPI_EC_FLAG_OBF));
287 	return x;
288 }
289 
290 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
291 {
292 	u8 x = inb(ec->data_addr);
293 
294 	ec->timestamp = jiffies;
295 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
296 	return x;
297 }
298 
299 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
300 {
301 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
302 	outb(command, ec->command_addr);
303 	ec->timestamp = jiffies;
304 }
305 
306 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
307 {
308 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
309 	outb(data, ec->data_addr);
310 	ec->timestamp = jiffies;
311 }
312 
313 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
314 static const char *acpi_ec_cmd_string(u8 cmd)
315 {
316 	switch (cmd) {
317 	case 0x80:
318 		return "RD_EC";
319 	case 0x81:
320 		return "WR_EC";
321 	case 0x82:
322 		return "BE_EC";
323 	case 0x83:
324 		return "BD_EC";
325 	case 0x84:
326 		return "QR_EC";
327 	}
328 	return "UNKNOWN";
329 }
330 #else
331 #define acpi_ec_cmd_string(cmd)		"UNDEF"
332 #endif
333 
334 /* --------------------------------------------------------------------------
335  *                           GPE Registers
336  * -------------------------------------------------------------------------- */
337 
338 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
339 {
340 	acpi_event_status gpe_status = 0;
341 
342 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
343 	return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
344 }
345 
346 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
347 {
348 	if (open)
349 		acpi_enable_gpe(NULL, ec->gpe);
350 	else {
351 		BUG_ON(ec->reference_count < 1);
352 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
353 	}
354 	if (acpi_ec_gpe_status_set(ec)) {
355 		/*
356 		 * On some platforms, EN=1 writes cannot trigger GPE. So
357 		 * software need to manually trigger a pseudo GPE event on
358 		 * EN=1 writes.
359 		 */
360 		ec_dbg_raw("Polling quirk");
361 		advance_transaction(ec, false);
362 	}
363 }
364 
365 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
366 {
367 	if (close)
368 		acpi_disable_gpe(NULL, ec->gpe);
369 	else {
370 		BUG_ON(ec->reference_count < 1);
371 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
372 	}
373 }
374 
375 /* --------------------------------------------------------------------------
376  *                           Transaction Management
377  * -------------------------------------------------------------------------- */
378 
379 static void acpi_ec_submit_request(struct acpi_ec *ec)
380 {
381 	ec->reference_count++;
382 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
383 	    ec->gpe >= 0 && ec->reference_count == 1)
384 		acpi_ec_enable_gpe(ec, true);
385 }
386 
387 static void acpi_ec_complete_request(struct acpi_ec *ec)
388 {
389 	bool flushed = false;
390 
391 	ec->reference_count--;
392 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
393 	    ec->gpe >= 0 && ec->reference_count == 0)
394 		acpi_ec_disable_gpe(ec, true);
395 	flushed = acpi_ec_flushed(ec);
396 	if (flushed)
397 		wake_up(&ec->wait);
398 }
399 
400 static void acpi_ec_mask_events(struct acpi_ec *ec)
401 {
402 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
403 		if (ec->gpe >= 0)
404 			acpi_ec_disable_gpe(ec, false);
405 		else
406 			disable_irq_nosync(ec->irq);
407 
408 		ec_dbg_drv("Polling enabled");
409 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
410 	}
411 }
412 
413 static void acpi_ec_unmask_events(struct acpi_ec *ec)
414 {
415 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
416 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
417 		if (ec->gpe >= 0)
418 			acpi_ec_enable_gpe(ec, false);
419 		else
420 			enable_irq(ec->irq);
421 
422 		ec_dbg_drv("Polling disabled");
423 	}
424 }
425 
426 /*
427  * acpi_ec_submit_flushable_request() - Increase the reference count unless
428  *                                      the flush operation is not in
429  *                                      progress
430  * @ec: the EC device
431  *
432  * This function must be used before taking a new action that should hold
433  * the reference count.  If this function returns false, then the action
434  * must be discarded or it will prevent the flush operation from being
435  * completed.
436  */
437 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
438 {
439 	if (!acpi_ec_started(ec))
440 		return false;
441 	acpi_ec_submit_request(ec);
442 	return true;
443 }
444 
445 static void acpi_ec_submit_query(struct acpi_ec *ec)
446 {
447 	acpi_ec_mask_events(ec);
448 	if (!acpi_ec_event_enabled(ec))
449 		return;
450 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
451 		ec_dbg_evt("Command(%s) submitted/blocked",
452 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
453 		ec->nr_pending_queries++;
454 		queue_work(ec_wq, &ec->work);
455 	}
456 }
457 
458 static void acpi_ec_complete_query(struct acpi_ec *ec)
459 {
460 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
461 		ec_dbg_evt("Command(%s) unblocked",
462 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
463 	acpi_ec_unmask_events(ec);
464 }
465 
466 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
467 {
468 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
469 		ec_log_drv("event unblocked");
470 	/*
471 	 * Unconditionally invoke this once after enabling the event
472 	 * handling mechanism to detect the pending events.
473 	 */
474 	advance_transaction(ec, false);
475 }
476 
477 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
478 {
479 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
480 		ec_log_drv("event blocked");
481 }
482 
483 /*
484  * Process _Q events that might have accumulated in the EC.
485  * Run with locked ec mutex.
486  */
487 static void acpi_ec_clear(struct acpi_ec *ec)
488 {
489 	int i, status;
490 	u8 value = 0;
491 
492 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
493 		status = acpi_ec_query(ec, &value);
494 		if (status || !value)
495 			break;
496 	}
497 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
498 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
499 	else
500 		pr_info("%d stale EC events cleared\n", i);
501 }
502 
503 static void acpi_ec_enable_event(struct acpi_ec *ec)
504 {
505 	unsigned long flags;
506 
507 	spin_lock_irqsave(&ec->lock, flags);
508 	if (acpi_ec_started(ec))
509 		__acpi_ec_enable_event(ec);
510 	spin_unlock_irqrestore(&ec->lock, flags);
511 
512 	/* Drain additional events if hardware requires that */
513 	if (EC_FLAGS_CLEAR_ON_RESUME)
514 		acpi_ec_clear(ec);
515 }
516 
517 #ifdef CONFIG_PM_SLEEP
518 static void __acpi_ec_flush_work(void)
519 {
520 	drain_workqueue(ec_wq); /* flush ec->work */
521 	flush_workqueue(ec_query_wq); /* flush queries */
522 }
523 
524 static void acpi_ec_disable_event(struct acpi_ec *ec)
525 {
526 	unsigned long flags;
527 
528 	spin_lock_irqsave(&ec->lock, flags);
529 	__acpi_ec_disable_event(ec);
530 	spin_unlock_irqrestore(&ec->lock, flags);
531 
532 	/*
533 	 * When ec_freeze_events is true, we need to flush events in
534 	 * the proper position before entering the noirq stage.
535 	 */
536 	__acpi_ec_flush_work();
537 }
538 
539 void acpi_ec_flush_work(void)
540 {
541 	/* Without ec_wq there is nothing to flush. */
542 	if (!ec_wq)
543 		return;
544 
545 	__acpi_ec_flush_work();
546 }
547 #endif /* CONFIG_PM_SLEEP */
548 
549 static bool acpi_ec_guard_event(struct acpi_ec *ec)
550 {
551 	bool guarded = true;
552 	unsigned long flags;
553 
554 	spin_lock_irqsave(&ec->lock, flags);
555 	/*
556 	 * If firmware SCI_EVT clearing timing is "event", we actually
557 	 * don't know when the SCI_EVT will be cleared by firmware after
558 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
559 	 * acceptable period.
560 	 *
561 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
562 	 * flagged, which means SCI_EVT check has just been performed.
563 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
564 	 * guarding should have already been performed (via
565 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
566 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
567 	 * ACPI_EC_COMMAND_POLL state immediately.
568 	 */
569 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
570 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
571 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
572 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
573 		guarded = false;
574 	spin_unlock_irqrestore(&ec->lock, flags);
575 	return guarded;
576 }
577 
578 static int ec_transaction_polled(struct acpi_ec *ec)
579 {
580 	unsigned long flags;
581 	int ret = 0;
582 
583 	spin_lock_irqsave(&ec->lock, flags);
584 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
585 		ret = 1;
586 	spin_unlock_irqrestore(&ec->lock, flags);
587 	return ret;
588 }
589 
590 static int ec_transaction_completed(struct acpi_ec *ec)
591 {
592 	unsigned long flags;
593 	int ret = 0;
594 
595 	spin_lock_irqsave(&ec->lock, flags);
596 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
597 		ret = 1;
598 	spin_unlock_irqrestore(&ec->lock, flags);
599 	return ret;
600 }
601 
602 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
603 {
604 	ec->curr->flags |= flag;
605 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
606 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
607 		    flag == ACPI_EC_COMMAND_POLL)
608 			acpi_ec_complete_query(ec);
609 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
610 		    flag == ACPI_EC_COMMAND_COMPLETE)
611 			acpi_ec_complete_query(ec);
612 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
613 		    flag == ACPI_EC_COMMAND_COMPLETE)
614 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
615 	}
616 }
617 
618 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
619 {
620 	if (t->irq_count < ec_storm_threshold)
621 		++t->irq_count;
622 
623 	/* Trigger if the threshold is 0 too. */
624 	if (t->irq_count == ec_storm_threshold)
625 		acpi_ec_mask_events(ec);
626 }
627 
628 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
629 {
630 	struct transaction *t = ec->curr;
631 	bool wakeup = false;
632 	u8 status;
633 
634 	ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
635 
636 	/*
637 	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
638 	 * changes to always trigger a GPE interrupt.
639 	 *
640 	 * GPE STS is a W1C register, which means:
641 	 *
642 	 * 1. Software can clear it without worrying about clearing the other
643 	 *    GPEs' STS bits when the hardware sets them in parallel.
644 	 *
645 	 * 2. As long as software can ensure only clearing it when it is set,
646 	 *    hardware won't set it in parallel.
647 	 */
648 	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
649 		acpi_clear_gpe(NULL, ec->gpe);
650 
651 	status = acpi_ec_read_status(ec);
652 
653 	/*
654 	 * Another IRQ or a guarded polling mode advancement is detected,
655 	 * the next QR_EC submission is then allowed.
656 	 */
657 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
658 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
659 		    (!ec->nr_pending_queries ||
660 		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
661 			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
662 			acpi_ec_complete_query(ec);
663 		}
664 		if (!t)
665 			goto out;
666 	}
667 
668 	if (t->flags & ACPI_EC_COMMAND_POLL) {
669 		if (t->wlen > t->wi) {
670 			if (!(status & ACPI_EC_FLAG_IBF))
671 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
672 			else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
673 				acpi_ec_spurious_interrupt(ec, t);
674 		} else if (t->rlen > t->ri) {
675 			if (status & ACPI_EC_FLAG_OBF) {
676 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
677 				if (t->rlen == t->ri) {
678 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
679 					wakeup = true;
680 					if (t->command == ACPI_EC_COMMAND_QUERY)
681 						ec_dbg_evt("Command(%s) completed by hardware",
682 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
683 				}
684 			} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
685 				acpi_ec_spurious_interrupt(ec, t);
686 			}
687 		} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
688 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
689 			wakeup = true;
690 		}
691 	} else if (!(status & ACPI_EC_FLAG_IBF)) {
692 		acpi_ec_write_cmd(ec, t->command);
693 		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
694 	}
695 
696 out:
697 	if (status & ACPI_EC_FLAG_SCI)
698 		acpi_ec_submit_query(ec);
699 
700 	if (wakeup && interrupt)
701 		wake_up(&ec->wait);
702 }
703 
704 static void start_transaction(struct acpi_ec *ec)
705 {
706 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
707 	ec->curr->flags = 0;
708 }
709 
710 static int ec_guard(struct acpi_ec *ec)
711 {
712 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
713 	unsigned long timeout = ec->timestamp + guard;
714 
715 	/* Ensure guarding period before polling EC status */
716 	do {
717 		if (ec->busy_polling) {
718 			/* Perform busy polling */
719 			if (ec_transaction_completed(ec))
720 				return 0;
721 			udelay(jiffies_to_usecs(guard));
722 		} else {
723 			/*
724 			 * Perform wait polling
725 			 * 1. Wait the transaction to be completed by the
726 			 *    GPE handler after the transaction enters
727 			 *    ACPI_EC_COMMAND_POLL state.
728 			 * 2. A special guarding logic is also required
729 			 *    for event clearing mode "event" before the
730 			 *    transaction enters ACPI_EC_COMMAND_POLL
731 			 *    state.
732 			 */
733 			if (!ec_transaction_polled(ec) &&
734 			    !acpi_ec_guard_event(ec))
735 				break;
736 			if (wait_event_timeout(ec->wait,
737 					       ec_transaction_completed(ec),
738 					       guard))
739 				return 0;
740 		}
741 	} while (time_before(jiffies, timeout));
742 	return -ETIME;
743 }
744 
745 static int ec_poll(struct acpi_ec *ec)
746 {
747 	unsigned long flags;
748 	int repeat = 5; /* number of command restarts */
749 
750 	while (repeat--) {
751 		unsigned long delay = jiffies +
752 			msecs_to_jiffies(ec_delay);
753 		do {
754 			if (!ec_guard(ec))
755 				return 0;
756 			spin_lock_irqsave(&ec->lock, flags);
757 			advance_transaction(ec, false);
758 			spin_unlock_irqrestore(&ec->lock, flags);
759 		} while (time_before(jiffies, delay));
760 		pr_debug("controller reset, restart transaction\n");
761 		spin_lock_irqsave(&ec->lock, flags);
762 		start_transaction(ec);
763 		spin_unlock_irqrestore(&ec->lock, flags);
764 	}
765 	return -ETIME;
766 }
767 
768 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
769 					struct transaction *t)
770 {
771 	unsigned long tmp;
772 	int ret = 0;
773 
774 	/* start transaction */
775 	spin_lock_irqsave(&ec->lock, tmp);
776 	/* Enable GPE for command processing (IBF=0/OBF=1) */
777 	if (!acpi_ec_submit_flushable_request(ec)) {
778 		ret = -EINVAL;
779 		goto unlock;
780 	}
781 	ec_dbg_ref(ec, "Increase command");
782 	/* following two actions should be kept atomic */
783 	ec->curr = t;
784 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
785 	start_transaction(ec);
786 	spin_unlock_irqrestore(&ec->lock, tmp);
787 
788 	ret = ec_poll(ec);
789 
790 	spin_lock_irqsave(&ec->lock, tmp);
791 	if (t->irq_count == ec_storm_threshold)
792 		acpi_ec_unmask_events(ec);
793 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
794 	ec->curr = NULL;
795 	/* Disable GPE for command processing (IBF=0/OBF=1) */
796 	acpi_ec_complete_request(ec);
797 	ec_dbg_ref(ec, "Decrease command");
798 unlock:
799 	spin_unlock_irqrestore(&ec->lock, tmp);
800 	return ret;
801 }
802 
803 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
804 {
805 	int status;
806 	u32 glk;
807 
808 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
809 		return -EINVAL;
810 	if (t->rdata)
811 		memset(t->rdata, 0, t->rlen);
812 
813 	mutex_lock(&ec->mutex);
814 	if (ec->global_lock) {
815 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
816 		if (ACPI_FAILURE(status)) {
817 			status = -ENODEV;
818 			goto unlock;
819 		}
820 	}
821 
822 	status = acpi_ec_transaction_unlocked(ec, t);
823 
824 	if (ec->global_lock)
825 		acpi_release_global_lock(glk);
826 unlock:
827 	mutex_unlock(&ec->mutex);
828 	return status;
829 }
830 
831 static int acpi_ec_burst_enable(struct acpi_ec *ec)
832 {
833 	u8 d;
834 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
835 				.wdata = NULL, .rdata = &d,
836 				.wlen = 0, .rlen = 1};
837 
838 	return acpi_ec_transaction(ec, &t);
839 }
840 
841 static int acpi_ec_burst_disable(struct acpi_ec *ec)
842 {
843 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
844 				.wdata = NULL, .rdata = NULL,
845 				.wlen = 0, .rlen = 0};
846 
847 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
848 				acpi_ec_transaction(ec, &t) : 0;
849 }
850 
851 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
852 {
853 	int result;
854 	u8 d;
855 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
856 				.wdata = &address, .rdata = &d,
857 				.wlen = 1, .rlen = 1};
858 
859 	result = acpi_ec_transaction(ec, &t);
860 	*data = d;
861 	return result;
862 }
863 
864 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
865 {
866 	u8 wdata[2] = { address, data };
867 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
868 				.wdata = wdata, .rdata = NULL,
869 				.wlen = 2, .rlen = 0};
870 
871 	return acpi_ec_transaction(ec, &t);
872 }
873 
874 int ec_read(u8 addr, u8 *val)
875 {
876 	int err;
877 	u8 temp_data;
878 
879 	if (!first_ec)
880 		return -ENODEV;
881 
882 	err = acpi_ec_read(first_ec, addr, &temp_data);
883 
884 	if (!err) {
885 		*val = temp_data;
886 		return 0;
887 	}
888 	return err;
889 }
890 EXPORT_SYMBOL(ec_read);
891 
892 int ec_write(u8 addr, u8 val)
893 {
894 	int err;
895 
896 	if (!first_ec)
897 		return -ENODEV;
898 
899 	err = acpi_ec_write(first_ec, addr, val);
900 
901 	return err;
902 }
903 EXPORT_SYMBOL(ec_write);
904 
905 int ec_transaction(u8 command,
906 		   const u8 *wdata, unsigned wdata_len,
907 		   u8 *rdata, unsigned rdata_len)
908 {
909 	struct transaction t = {.command = command,
910 				.wdata = wdata, .rdata = rdata,
911 				.wlen = wdata_len, .rlen = rdata_len};
912 
913 	if (!first_ec)
914 		return -ENODEV;
915 
916 	return acpi_ec_transaction(first_ec, &t);
917 }
918 EXPORT_SYMBOL(ec_transaction);
919 
920 /* Get the handle to the EC device */
921 acpi_handle ec_get_handle(void)
922 {
923 	if (!first_ec)
924 		return NULL;
925 	return first_ec->handle;
926 }
927 EXPORT_SYMBOL(ec_get_handle);
928 
929 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
930 {
931 	unsigned long flags;
932 
933 	spin_lock_irqsave(&ec->lock, flags);
934 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
935 		ec_dbg_drv("Starting EC");
936 		/* Enable GPE for event processing (SCI_EVT=1) */
937 		if (!resuming) {
938 			acpi_ec_submit_request(ec);
939 			ec_dbg_ref(ec, "Increase driver");
940 		}
941 		ec_log_drv("EC started");
942 	}
943 	spin_unlock_irqrestore(&ec->lock, flags);
944 }
945 
946 static bool acpi_ec_stopped(struct acpi_ec *ec)
947 {
948 	unsigned long flags;
949 	bool flushed;
950 
951 	spin_lock_irqsave(&ec->lock, flags);
952 	flushed = acpi_ec_flushed(ec);
953 	spin_unlock_irqrestore(&ec->lock, flags);
954 	return flushed;
955 }
956 
957 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
958 {
959 	unsigned long flags;
960 
961 	spin_lock_irqsave(&ec->lock, flags);
962 	if (acpi_ec_started(ec)) {
963 		ec_dbg_drv("Stopping EC");
964 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
965 		spin_unlock_irqrestore(&ec->lock, flags);
966 		wait_event(ec->wait, acpi_ec_stopped(ec));
967 		spin_lock_irqsave(&ec->lock, flags);
968 		/* Disable GPE for event processing (SCI_EVT=1) */
969 		if (!suspending) {
970 			acpi_ec_complete_request(ec);
971 			ec_dbg_ref(ec, "Decrease driver");
972 		} else if (!ec_freeze_events)
973 			__acpi_ec_disable_event(ec);
974 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
975 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
976 		ec_log_drv("EC stopped");
977 	}
978 	spin_unlock_irqrestore(&ec->lock, flags);
979 }
980 
981 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
982 {
983 	unsigned long flags;
984 
985 	spin_lock_irqsave(&ec->lock, flags);
986 	ec->busy_polling = true;
987 	ec->polling_guard = 0;
988 	ec_log_drv("interrupt blocked");
989 	spin_unlock_irqrestore(&ec->lock, flags);
990 }
991 
992 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
993 {
994 	unsigned long flags;
995 
996 	spin_lock_irqsave(&ec->lock, flags);
997 	ec->busy_polling = ec_busy_polling;
998 	ec->polling_guard = ec_polling_guard;
999 	ec_log_drv("interrupt unblocked");
1000 	spin_unlock_irqrestore(&ec->lock, flags);
1001 }
1002 
1003 void acpi_ec_block_transactions(void)
1004 {
1005 	struct acpi_ec *ec = first_ec;
1006 
1007 	if (!ec)
1008 		return;
1009 
1010 	mutex_lock(&ec->mutex);
1011 	/* Prevent transactions from being carried out */
1012 	acpi_ec_stop(ec, true);
1013 	mutex_unlock(&ec->mutex);
1014 }
1015 
1016 void acpi_ec_unblock_transactions(void)
1017 {
1018 	/*
1019 	 * Allow transactions to happen again (this function is called from
1020 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1021 	 */
1022 	if (first_ec)
1023 		acpi_ec_start(first_ec, true);
1024 }
1025 
1026 /* --------------------------------------------------------------------------
1027                                 Event Management
1028    -------------------------------------------------------------------------- */
1029 static struct acpi_ec_query_handler *
1030 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1031 {
1032 	struct acpi_ec_query_handler *handler;
1033 
1034 	mutex_lock(&ec->mutex);
1035 	list_for_each_entry(handler, &ec->list, node) {
1036 		if (value == handler->query_bit) {
1037 			kref_get(&handler->kref);
1038 			mutex_unlock(&ec->mutex);
1039 			return handler;
1040 		}
1041 	}
1042 	mutex_unlock(&ec->mutex);
1043 	return NULL;
1044 }
1045 
1046 static void acpi_ec_query_handler_release(struct kref *kref)
1047 {
1048 	struct acpi_ec_query_handler *handler =
1049 		container_of(kref, struct acpi_ec_query_handler, kref);
1050 
1051 	kfree(handler);
1052 }
1053 
1054 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1055 {
1056 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1057 }
1058 
1059 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1060 			      acpi_handle handle, acpi_ec_query_func func,
1061 			      void *data)
1062 {
1063 	struct acpi_ec_query_handler *handler =
1064 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1065 
1066 	if (!handler)
1067 		return -ENOMEM;
1068 
1069 	handler->query_bit = query_bit;
1070 	handler->handle = handle;
1071 	handler->func = func;
1072 	handler->data = data;
1073 	mutex_lock(&ec->mutex);
1074 	kref_init(&handler->kref);
1075 	list_add(&handler->node, &ec->list);
1076 	mutex_unlock(&ec->mutex);
1077 	return 0;
1078 }
1079 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1080 
1081 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1082 					  bool remove_all, u8 query_bit)
1083 {
1084 	struct acpi_ec_query_handler *handler, *tmp;
1085 	LIST_HEAD(free_list);
1086 
1087 	mutex_lock(&ec->mutex);
1088 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1089 		if (remove_all || query_bit == handler->query_bit) {
1090 			list_del_init(&handler->node);
1091 			list_add(&handler->node, &free_list);
1092 		}
1093 	}
1094 	mutex_unlock(&ec->mutex);
1095 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1096 		acpi_ec_put_query_handler(handler);
1097 }
1098 
1099 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1100 {
1101 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1102 }
1103 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1104 
1105 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1106 {
1107 	struct acpi_ec_query *q;
1108 	struct transaction *t;
1109 
1110 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1111 	if (!q)
1112 		return NULL;
1113 	INIT_WORK(&q->work, acpi_ec_event_processor);
1114 	t = &q->transaction;
1115 	t->command = ACPI_EC_COMMAND_QUERY;
1116 	t->rdata = pval;
1117 	t->rlen = 1;
1118 	return q;
1119 }
1120 
1121 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1122 {
1123 	if (q) {
1124 		if (q->handler)
1125 			acpi_ec_put_query_handler(q->handler);
1126 		kfree(q);
1127 	}
1128 }
1129 
1130 static void acpi_ec_event_processor(struct work_struct *work)
1131 {
1132 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1133 	struct acpi_ec_query_handler *handler = q->handler;
1134 
1135 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1136 	if (handler->func)
1137 		handler->func(handler->data);
1138 	else if (handler->handle)
1139 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1140 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1141 	acpi_ec_delete_query(q);
1142 }
1143 
1144 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1145 {
1146 	u8 value = 0;
1147 	int result;
1148 	struct acpi_ec_query *q;
1149 
1150 	q = acpi_ec_create_query(&value);
1151 	if (!q)
1152 		return -ENOMEM;
1153 
1154 	/*
1155 	 * Query the EC to find out which _Qxx method we need to evaluate.
1156 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1157 	 * bit to be cleared (and thus clearing the interrupt source).
1158 	 */
1159 	result = acpi_ec_transaction(ec, &q->transaction);
1160 	if (!value)
1161 		result = -ENODATA;
1162 	if (result)
1163 		goto err_exit;
1164 
1165 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1166 	if (!q->handler) {
1167 		result = -ENODATA;
1168 		goto err_exit;
1169 	}
1170 
1171 	/*
1172 	 * It is reported that _Qxx are evaluated in a parallel way on
1173 	 * Windows:
1174 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1175 	 *
1176 	 * Put this log entry before schedule_work() in order to make
1177 	 * it appearing before any other log entries occurred during the
1178 	 * work queue execution.
1179 	 */
1180 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1181 	if (!queue_work(ec_query_wq, &q->work)) {
1182 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1183 		result = -EBUSY;
1184 	}
1185 
1186 err_exit:
1187 	if (result)
1188 		acpi_ec_delete_query(q);
1189 	if (data)
1190 		*data = value;
1191 	return result;
1192 }
1193 
1194 static void acpi_ec_check_event(struct acpi_ec *ec)
1195 {
1196 	unsigned long flags;
1197 
1198 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1199 		if (ec_guard(ec)) {
1200 			spin_lock_irqsave(&ec->lock, flags);
1201 			/*
1202 			 * Take care of the SCI_EVT unless no one else is
1203 			 * taking care of it.
1204 			 */
1205 			if (!ec->curr)
1206 				advance_transaction(ec, false);
1207 			spin_unlock_irqrestore(&ec->lock, flags);
1208 		}
1209 	}
1210 }
1211 
1212 static void acpi_ec_event_handler(struct work_struct *work)
1213 {
1214 	unsigned long flags;
1215 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1216 
1217 	ec_dbg_evt("Event started");
1218 
1219 	spin_lock_irqsave(&ec->lock, flags);
1220 	while (ec->nr_pending_queries) {
1221 		spin_unlock_irqrestore(&ec->lock, flags);
1222 		(void)acpi_ec_query(ec, NULL);
1223 		spin_lock_irqsave(&ec->lock, flags);
1224 		ec->nr_pending_queries--;
1225 		/*
1226 		 * Before exit, make sure that this work item can be
1227 		 * scheduled again. There might be QR_EC failures, leaving
1228 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1229 		 * item from being scheduled again.
1230 		 */
1231 		if (!ec->nr_pending_queries) {
1232 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1233 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1234 				acpi_ec_complete_query(ec);
1235 		}
1236 	}
1237 	spin_unlock_irqrestore(&ec->lock, flags);
1238 
1239 	ec_dbg_evt("Event stopped");
1240 
1241 	acpi_ec_check_event(ec);
1242 }
1243 
1244 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1245 {
1246 	unsigned long flags;
1247 
1248 	spin_lock_irqsave(&ec->lock, flags);
1249 	advance_transaction(ec, true);
1250 	spin_unlock_irqrestore(&ec->lock, flags);
1251 }
1252 
1253 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1254 			       u32 gpe_number, void *data)
1255 {
1256 	acpi_ec_handle_interrupt(data);
1257 	return ACPI_INTERRUPT_HANDLED;
1258 }
1259 
1260 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1261 {
1262 	acpi_ec_handle_interrupt(data);
1263 	return IRQ_HANDLED;
1264 }
1265 
1266 /* --------------------------------------------------------------------------
1267  *                           Address Space Management
1268  * -------------------------------------------------------------------------- */
1269 
1270 static acpi_status
1271 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1272 		      u32 bits, u64 *value64,
1273 		      void *handler_context, void *region_context)
1274 {
1275 	struct acpi_ec *ec = handler_context;
1276 	int result = 0, i, bytes = bits / 8;
1277 	u8 *value = (u8 *)value64;
1278 
1279 	if ((address > 0xFF) || !value || !handler_context)
1280 		return AE_BAD_PARAMETER;
1281 
1282 	if (function != ACPI_READ && function != ACPI_WRITE)
1283 		return AE_BAD_PARAMETER;
1284 
1285 	if (ec->busy_polling || bits > 8)
1286 		acpi_ec_burst_enable(ec);
1287 
1288 	for (i = 0; i < bytes; ++i, ++address, ++value)
1289 		result = (function == ACPI_READ) ?
1290 			acpi_ec_read(ec, address, value) :
1291 			acpi_ec_write(ec, address, *value);
1292 
1293 	if (ec->busy_polling || bits > 8)
1294 		acpi_ec_burst_disable(ec);
1295 
1296 	switch (result) {
1297 	case -EINVAL:
1298 		return AE_BAD_PARAMETER;
1299 	case -ENODEV:
1300 		return AE_NOT_FOUND;
1301 	case -ETIME:
1302 		return AE_TIME;
1303 	default:
1304 		return AE_OK;
1305 	}
1306 }
1307 
1308 /* --------------------------------------------------------------------------
1309  *                             Driver Interface
1310  * -------------------------------------------------------------------------- */
1311 
1312 static acpi_status
1313 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1314 
1315 static void acpi_ec_free(struct acpi_ec *ec)
1316 {
1317 	if (first_ec == ec)
1318 		first_ec = NULL;
1319 	if (boot_ec == ec)
1320 		boot_ec = NULL;
1321 	kfree(ec);
1322 }
1323 
1324 static struct acpi_ec *acpi_ec_alloc(void)
1325 {
1326 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1327 
1328 	if (!ec)
1329 		return NULL;
1330 	mutex_init(&ec->mutex);
1331 	init_waitqueue_head(&ec->wait);
1332 	INIT_LIST_HEAD(&ec->list);
1333 	spin_lock_init(&ec->lock);
1334 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1335 	ec->timestamp = jiffies;
1336 	ec->busy_polling = true;
1337 	ec->polling_guard = 0;
1338 	ec->gpe = -1;
1339 	ec->irq = -1;
1340 	return ec;
1341 }
1342 
1343 static acpi_status
1344 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1345 			       void *context, void **return_value)
1346 {
1347 	char node_name[5];
1348 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1349 	struct acpi_ec *ec = context;
1350 	int value = 0;
1351 	acpi_status status;
1352 
1353 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1354 
1355 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1356 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1357 	return AE_OK;
1358 }
1359 
1360 static acpi_status
1361 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1362 {
1363 	acpi_status status;
1364 	unsigned long long tmp = 0;
1365 	struct acpi_ec *ec = context;
1366 
1367 	/* clear addr values, ec_parse_io_ports depend on it */
1368 	ec->command_addr = ec->data_addr = 0;
1369 
1370 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1371 				     ec_parse_io_ports, ec);
1372 	if (ACPI_FAILURE(status))
1373 		return status;
1374 	if (ec->data_addr == 0 || ec->command_addr == 0)
1375 		return AE_OK;
1376 
1377 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1378 		/*
1379 		 * Always inherit the GPE number setting from the ECDT
1380 		 * EC.
1381 		 */
1382 		ec->gpe = boot_ec->gpe;
1383 	} else {
1384 		/* Get GPE bit assignment (EC events). */
1385 		/* TODO: Add support for _GPE returning a package */
1386 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1387 		if (ACPI_SUCCESS(status))
1388 			ec->gpe = tmp;
1389 
1390 		/*
1391 		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1392 		 * platforms which use GpioInt instead of GPE.
1393 		 */
1394 	}
1395 	/* Use the global lock for all EC transactions? */
1396 	tmp = 0;
1397 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1398 	ec->global_lock = tmp;
1399 	ec->handle = handle;
1400 	return AE_CTRL_TERMINATE;
1401 }
1402 
1403 static bool install_gpe_event_handler(struct acpi_ec *ec)
1404 {
1405 	acpi_status status;
1406 
1407 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1408 					      ACPI_GPE_EDGE_TRIGGERED,
1409 					      &acpi_ec_gpe_handler, ec);
1410 	if (ACPI_FAILURE(status))
1411 		return false;
1412 
1413 	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1414 		acpi_ec_enable_gpe(ec, true);
1415 
1416 	return true;
1417 }
1418 
1419 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1420 {
1421 	return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1422 			   "ACPI EC", ec) >= 0;
1423 }
1424 
1425 /**
1426  * ec_install_handlers - Install service callbacks and register query methods.
1427  * @ec: Target EC.
1428  * @device: ACPI device object corresponding to @ec.
1429  *
1430  * Install a handler for the EC address space type unless it has been installed
1431  * already.  If @device is not NULL, also look for EC query methods in the
1432  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1433  * handler for the EC, if possible.
1434  *
1435  * Return:
1436  * -ENODEV if the address space handler cannot be installed, which means
1437  *  "unable to handle transactions",
1438  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1439  * or 0 (success) otherwise.
1440  */
1441 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1442 {
1443 	acpi_status status;
1444 
1445 	acpi_ec_start(ec, false);
1446 
1447 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1448 		acpi_ec_enter_noirq(ec);
1449 		status = acpi_install_address_space_handler(ec->handle,
1450 							    ACPI_ADR_SPACE_EC,
1451 							    &acpi_ec_space_handler,
1452 							    NULL, ec);
1453 		if (ACPI_FAILURE(status)) {
1454 			acpi_ec_stop(ec, false);
1455 			return -ENODEV;
1456 		}
1457 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1458 	}
1459 
1460 	if (!device)
1461 		return 0;
1462 
1463 	if (ec->gpe < 0) {
1464 		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1465 		int irq = acpi_dev_gpio_irq_get(device, 0);
1466 		/*
1467 		 * Bail out right away for deferred probing or complete the
1468 		 * initialization regardless of any other errors.
1469 		 */
1470 		if (irq == -EPROBE_DEFER)
1471 			return -EPROBE_DEFER;
1472 		else if (irq >= 0)
1473 			ec->irq = irq;
1474 	}
1475 
1476 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1477 		/* Find and register all query methods */
1478 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1479 				    acpi_ec_register_query_methods,
1480 				    NULL, ec, NULL);
1481 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1482 	}
1483 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1484 		bool ready = false;
1485 
1486 		if (ec->gpe >= 0)
1487 			ready = install_gpe_event_handler(ec);
1488 		else if (ec->irq >= 0)
1489 			ready = install_gpio_irq_event_handler(ec);
1490 
1491 		if (ready) {
1492 			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1493 			acpi_ec_leave_noirq(ec);
1494 		}
1495 		/*
1496 		 * Failures to install an event handler are not fatal, because
1497 		 * the EC can be polled for events.
1498 		 */
1499 	}
1500 	/* EC is fully operational, allow queries */
1501 	acpi_ec_enable_event(ec);
1502 
1503 	return 0;
1504 }
1505 
1506 static void ec_remove_handlers(struct acpi_ec *ec)
1507 {
1508 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1509 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1510 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1511 			pr_err("failed to remove space handler\n");
1512 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1513 	}
1514 
1515 	/*
1516 	 * Stops handling the EC transactions after removing the operation
1517 	 * region handler. This is required because _REG(DISCONNECT)
1518 	 * invoked during the removal can result in new EC transactions.
1519 	 *
1520 	 * Flushes the EC requests and thus disables the GPE before
1521 	 * removing the GPE handler. This is required by the current ACPICA
1522 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1523 	 * it is indicated but there is no way to handle it. So the drivers
1524 	 * must disable the GPEs prior to removing the GPE handlers.
1525 	 */
1526 	acpi_ec_stop(ec, false);
1527 
1528 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1529 		if (ec->gpe >= 0 &&
1530 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1531 				 &acpi_ec_gpe_handler)))
1532 			pr_err("failed to remove gpe handler\n");
1533 
1534 		if (ec->irq >= 0)
1535 			free_irq(ec->irq, ec);
1536 
1537 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1538 	}
1539 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1540 		acpi_ec_remove_query_handlers(ec, true, 0);
1541 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1542 	}
1543 }
1544 
1545 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1546 {
1547 	int ret;
1548 
1549 	ret = ec_install_handlers(ec, device);
1550 	if (ret)
1551 		return ret;
1552 
1553 	/* First EC capable of handling transactions */
1554 	if (!first_ec)
1555 		first_ec = ec;
1556 
1557 	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1558 		ec->data_addr);
1559 
1560 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1561 		if (ec->gpe >= 0)
1562 			pr_info("GPE=0x%x\n", ec->gpe);
1563 		else
1564 			pr_info("IRQ=%d\n", ec->irq);
1565 	}
1566 
1567 	return ret;
1568 }
1569 
1570 static int acpi_ec_add(struct acpi_device *device)
1571 {
1572 	struct acpi_ec *ec;
1573 	int ret;
1574 
1575 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1576 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1577 
1578 	if (boot_ec && (boot_ec->handle == device->handle ||
1579 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1580 		/* Fast path: this device corresponds to the boot EC. */
1581 		ec = boot_ec;
1582 	} else {
1583 		acpi_status status;
1584 
1585 		ec = acpi_ec_alloc();
1586 		if (!ec)
1587 			return -ENOMEM;
1588 
1589 		status = ec_parse_device(device->handle, 0, ec, NULL);
1590 		if (status != AE_CTRL_TERMINATE) {
1591 			ret = -EINVAL;
1592 			goto err;
1593 		}
1594 
1595 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1596 		    ec->data_addr == boot_ec->data_addr) {
1597 			/*
1598 			 * Trust PNP0C09 namespace location rather than
1599 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1600 			 * because of ASUS quirks, so do not change
1601 			 * boot_ec->gpe to ec->gpe.
1602 			 */
1603 			boot_ec->handle = ec->handle;
1604 			acpi_handle_debug(ec->handle, "duplicated.\n");
1605 			acpi_ec_free(ec);
1606 			ec = boot_ec;
1607 		}
1608 	}
1609 
1610 	ret = acpi_ec_setup(ec, device);
1611 	if (ret)
1612 		goto err;
1613 
1614 	if (ec == boot_ec)
1615 		acpi_handle_info(boot_ec->handle,
1616 				 "Boot %s EC initialization complete\n",
1617 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1618 
1619 	acpi_handle_info(ec->handle,
1620 			 "EC: Used to handle transactions and events\n");
1621 
1622 	device->driver_data = ec;
1623 
1624 	ret = !!request_region(ec->data_addr, 1, "EC data");
1625 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1626 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1627 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1628 
1629 	/* Reprobe devices depending on the EC */
1630 	acpi_walk_dep_device_list(ec->handle);
1631 
1632 	acpi_handle_debug(ec->handle, "enumerated.\n");
1633 	return 0;
1634 
1635 err:
1636 	if (ec != boot_ec)
1637 		acpi_ec_free(ec);
1638 
1639 	return ret;
1640 }
1641 
1642 static int acpi_ec_remove(struct acpi_device *device)
1643 {
1644 	struct acpi_ec *ec;
1645 
1646 	if (!device)
1647 		return -EINVAL;
1648 
1649 	ec = acpi_driver_data(device);
1650 	release_region(ec->data_addr, 1);
1651 	release_region(ec->command_addr, 1);
1652 	device->driver_data = NULL;
1653 	if (ec != boot_ec) {
1654 		ec_remove_handlers(ec);
1655 		acpi_ec_free(ec);
1656 	}
1657 	return 0;
1658 }
1659 
1660 static acpi_status
1661 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1662 {
1663 	struct acpi_ec *ec = context;
1664 
1665 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1666 		return AE_OK;
1667 
1668 	/*
1669 	 * The first address region returned is the data port, and
1670 	 * the second address region returned is the status/command
1671 	 * port.
1672 	 */
1673 	if (ec->data_addr == 0)
1674 		ec->data_addr = resource->data.io.minimum;
1675 	else if (ec->command_addr == 0)
1676 		ec->command_addr = resource->data.io.minimum;
1677 	else
1678 		return AE_CTRL_TERMINATE;
1679 
1680 	return AE_OK;
1681 }
1682 
1683 static const struct acpi_device_id ec_device_ids[] = {
1684 	{"PNP0C09", 0},
1685 	{ACPI_ECDT_HID, 0},
1686 	{"", 0},
1687 };
1688 
1689 /*
1690  * This function is not Windows-compatible as Windows never enumerates the
1691  * namespace EC before the main ACPI device enumeration process. It is
1692  * retained for historical reason and will be deprecated in the future.
1693  */
1694 void __init acpi_ec_dsdt_probe(void)
1695 {
1696 	struct acpi_ec *ec;
1697 	acpi_status status;
1698 	int ret;
1699 
1700 	/*
1701 	 * If a platform has ECDT, there is no need to proceed as the
1702 	 * following probe is not a part of the ACPI device enumeration,
1703 	 * executing _STA is not safe, and thus this probe may risk of
1704 	 * picking up an invalid EC device.
1705 	 */
1706 	if (boot_ec)
1707 		return;
1708 
1709 	ec = acpi_ec_alloc();
1710 	if (!ec)
1711 		return;
1712 
1713 	/*
1714 	 * At this point, the namespace is initialized, so start to find
1715 	 * the namespace objects.
1716 	 */
1717 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1718 	if (ACPI_FAILURE(status) || !ec->handle) {
1719 		acpi_ec_free(ec);
1720 		return;
1721 	}
1722 
1723 	/*
1724 	 * When the DSDT EC is available, always re-configure boot EC to
1725 	 * have _REG evaluated. _REG can only be evaluated after the
1726 	 * namespace initialization.
1727 	 * At this point, the GPE is not fully initialized, so do not to
1728 	 * handle the events.
1729 	 */
1730 	ret = acpi_ec_setup(ec, NULL);
1731 	if (ret) {
1732 		acpi_ec_free(ec);
1733 		return;
1734 	}
1735 
1736 	boot_ec = ec;
1737 
1738 	acpi_handle_info(ec->handle,
1739 			 "Boot DSDT EC used to handle transactions\n");
1740 }
1741 
1742 /*
1743  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1744  *
1745  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1746  * found a matching object in the namespace.
1747  *
1748  * Next, in case the DSDT EC is not functioning, it is still necessary to
1749  * provide a functional ECDT EC to handle events, so add an extra device object
1750  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1751  *
1752  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1753  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1754  */
1755 static void __init acpi_ec_ecdt_start(void)
1756 {
1757 	struct acpi_table_ecdt *ecdt_ptr;
1758 	acpi_handle handle;
1759 	acpi_status status;
1760 
1761 	/* Bail out if a matching EC has been found in the namespace. */
1762 	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1763 		return;
1764 
1765 	/* Look up the object pointed to from the ECDT in the namespace. */
1766 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1767 				(struct acpi_table_header **)&ecdt_ptr);
1768 	if (ACPI_FAILURE(status))
1769 		return;
1770 
1771 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1772 	if (ACPI_SUCCESS(status)) {
1773 		boot_ec->handle = handle;
1774 
1775 		/* Add a special ACPI device object to represent the boot EC. */
1776 		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1777 	}
1778 
1779 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1780 }
1781 
1782 /*
1783  * On some hardware it is necessary to clear events accumulated by the EC during
1784  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1785  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1786  *
1787  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1788  *
1789  * Ideally, the EC should also be instructed NOT to accumulate events during
1790  * sleep (which Windows seems to do somehow), but the interface to control this
1791  * behaviour is not known at this time.
1792  *
1793  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1794  * however it is very likely that other Samsung models are affected.
1795  *
1796  * On systems which don't accumulate _Q events during sleep, this extra check
1797  * should be harmless.
1798  */
1799 static int ec_clear_on_resume(const struct dmi_system_id *id)
1800 {
1801 	pr_debug("Detected system needing EC poll on resume.\n");
1802 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1803 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1804 	return 0;
1805 }
1806 
1807 /*
1808  * Some ECDTs contain wrong register addresses.
1809  * MSI MS-171F
1810  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1811  */
1812 static int ec_correct_ecdt(const struct dmi_system_id *id)
1813 {
1814 	pr_debug("Detected system needing ECDT address correction.\n");
1815 	EC_FLAGS_CORRECT_ECDT = 1;
1816 	return 0;
1817 }
1818 
1819 /*
1820  * Some DSDTs contain wrong GPE setting.
1821  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1822  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1823  */
1824 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1825 {
1826 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1827 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1828 	return 0;
1829 }
1830 
1831 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1832 	{
1833 	ec_correct_ecdt, "MSI MS-171F", {
1834 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1835 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1836 	{
1837 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1838 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1839 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1840 	{
1841 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1842 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1843 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1844 	{
1845 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1846 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1847 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1848 	{
1849 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1850 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1851 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1852 	{
1853 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1854 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1855 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1856 	{
1857 	ec_clear_on_resume, "Samsung hardware", {
1858 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1859 	{},
1860 };
1861 
1862 void __init acpi_ec_ecdt_probe(void)
1863 {
1864 	struct acpi_table_ecdt *ecdt_ptr;
1865 	struct acpi_ec *ec;
1866 	acpi_status status;
1867 	int ret;
1868 
1869 	/* Generate a boot ec context. */
1870 	dmi_check_system(ec_dmi_table);
1871 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1872 				(struct acpi_table_header **)&ecdt_ptr);
1873 	if (ACPI_FAILURE(status))
1874 		return;
1875 
1876 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1877 		/*
1878 		 * Asus X50GL:
1879 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1880 		 */
1881 		goto out;
1882 	}
1883 
1884 	ec = acpi_ec_alloc();
1885 	if (!ec)
1886 		goto out;
1887 
1888 	if (EC_FLAGS_CORRECT_ECDT) {
1889 		ec->command_addr = ecdt_ptr->data.address;
1890 		ec->data_addr = ecdt_ptr->control.address;
1891 	} else {
1892 		ec->command_addr = ecdt_ptr->control.address;
1893 		ec->data_addr = ecdt_ptr->data.address;
1894 	}
1895 
1896 	/*
1897 	 * Ignore the GPE value on Reduced Hardware platforms.
1898 	 * Some products have this set to an erroneous value.
1899 	 */
1900 	if (!acpi_gbl_reduced_hardware)
1901 		ec->gpe = ecdt_ptr->gpe;
1902 
1903 	ec->handle = ACPI_ROOT_OBJECT;
1904 
1905 	/*
1906 	 * At this point, the namespace is not initialized, so do not find
1907 	 * the namespace objects, or handle the events.
1908 	 */
1909 	ret = acpi_ec_setup(ec, NULL);
1910 	if (ret) {
1911 		acpi_ec_free(ec);
1912 		goto out;
1913 	}
1914 
1915 	boot_ec = ec;
1916 	boot_ec_is_ecdt = true;
1917 
1918 	pr_info("Boot ECDT EC used to handle transactions\n");
1919 
1920 out:
1921 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1922 }
1923 
1924 #ifdef CONFIG_PM_SLEEP
1925 static int acpi_ec_suspend(struct device *dev)
1926 {
1927 	struct acpi_ec *ec =
1928 		acpi_driver_data(to_acpi_device(dev));
1929 
1930 	if (!pm_suspend_no_platform() && ec_freeze_events)
1931 		acpi_ec_disable_event(ec);
1932 	return 0;
1933 }
1934 
1935 static int acpi_ec_suspend_noirq(struct device *dev)
1936 {
1937 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1938 
1939 	/*
1940 	 * The SCI handler doesn't run at this point, so the GPE can be
1941 	 * masked at the low level without side effects.
1942 	 */
1943 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1944 	    ec->gpe >= 0 && ec->reference_count >= 1)
1945 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1946 
1947 	acpi_ec_enter_noirq(ec);
1948 
1949 	return 0;
1950 }
1951 
1952 static int acpi_ec_resume_noirq(struct device *dev)
1953 {
1954 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1955 
1956 	acpi_ec_leave_noirq(ec);
1957 
1958 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1959 	    ec->gpe >= 0 && ec->reference_count >= 1)
1960 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1961 
1962 	return 0;
1963 }
1964 
1965 static int acpi_ec_resume(struct device *dev)
1966 {
1967 	struct acpi_ec *ec =
1968 		acpi_driver_data(to_acpi_device(dev));
1969 
1970 	acpi_ec_enable_event(ec);
1971 	return 0;
1972 }
1973 
1974 void acpi_ec_mark_gpe_for_wake(void)
1975 {
1976 	if (first_ec && !ec_no_wakeup)
1977 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1978 }
1979 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1980 
1981 void acpi_ec_set_gpe_wake_mask(u8 action)
1982 {
1983 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1984 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1985 }
1986 
1987 bool acpi_ec_dispatch_gpe(void)
1988 {
1989 	u32 ret;
1990 
1991 	if (!first_ec)
1992 		return acpi_any_gpe_status_set(U32_MAX);
1993 
1994 	/*
1995 	 * Report wakeup if the status bit is set for any enabled GPE other
1996 	 * than the EC one.
1997 	 */
1998 	if (acpi_any_gpe_status_set(first_ec->gpe))
1999 		return true;
2000 
2001 	/*
2002 	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2003 	 * to allow the caller to process events properly after that.
2004 	 */
2005 	ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2006 	if (ret == ACPI_INTERRUPT_HANDLED)
2007 		pm_pr_dbg("ACPI EC GPE dispatched\n");
2008 
2009 	/* Flush the event and query workqueues. */
2010 	acpi_ec_flush_work();
2011 
2012 	return false;
2013 }
2014 #endif /* CONFIG_PM_SLEEP */
2015 
2016 static const struct dev_pm_ops acpi_ec_pm = {
2017 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2018 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2019 };
2020 
2021 static int param_set_event_clearing(const char *val,
2022 				    const struct kernel_param *kp)
2023 {
2024 	int result = 0;
2025 
2026 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2027 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2028 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2029 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2030 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2031 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2032 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2033 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2034 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2035 	} else
2036 		result = -EINVAL;
2037 	return result;
2038 }
2039 
2040 static int param_get_event_clearing(char *buffer,
2041 				    const struct kernel_param *kp)
2042 {
2043 	switch (ec_event_clearing) {
2044 	case ACPI_EC_EVT_TIMING_STATUS:
2045 		return sprintf(buffer, "status\n");
2046 	case ACPI_EC_EVT_TIMING_QUERY:
2047 		return sprintf(buffer, "query\n");
2048 	case ACPI_EC_EVT_TIMING_EVENT:
2049 		return sprintf(buffer, "event\n");
2050 	default:
2051 		return sprintf(buffer, "invalid\n");
2052 	}
2053 	return 0;
2054 }
2055 
2056 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2057 		  NULL, 0644);
2058 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2059 
2060 static struct acpi_driver acpi_ec_driver = {
2061 	.name = "ec",
2062 	.class = ACPI_EC_CLASS,
2063 	.ids = ec_device_ids,
2064 	.ops = {
2065 		.add = acpi_ec_add,
2066 		.remove = acpi_ec_remove,
2067 		},
2068 	.drv.pm = &acpi_ec_pm,
2069 };
2070 
2071 static void acpi_ec_destroy_workqueues(void)
2072 {
2073 	if (ec_wq) {
2074 		destroy_workqueue(ec_wq);
2075 		ec_wq = NULL;
2076 	}
2077 	if (ec_query_wq) {
2078 		destroy_workqueue(ec_query_wq);
2079 		ec_query_wq = NULL;
2080 	}
2081 }
2082 
2083 static int acpi_ec_init_workqueues(void)
2084 {
2085 	if (!ec_wq)
2086 		ec_wq = alloc_ordered_workqueue("kec", 0);
2087 
2088 	if (!ec_query_wq)
2089 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2090 
2091 	if (!ec_wq || !ec_query_wq) {
2092 		acpi_ec_destroy_workqueues();
2093 		return -ENODEV;
2094 	}
2095 	return 0;
2096 }
2097 
2098 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2099 	{
2100 		.ident = "Thinkpad X1 Carbon 6th",
2101 		.matches = {
2102 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2103 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2104 		},
2105 	},
2106 	{
2107 		.ident = "ThinkPad X1 Carbon 6th",
2108 		.matches = {
2109 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2110 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2111 		},
2112 	},
2113 	{
2114 		.ident = "ThinkPad X1 Yoga 3rd",
2115 		.matches = {
2116 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2117 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2118 		},
2119 	},
2120 	{ },
2121 };
2122 
2123 void __init acpi_ec_init(void)
2124 {
2125 	int result;
2126 
2127 	result = acpi_ec_init_workqueues();
2128 	if (result)
2129 		return;
2130 
2131 	/*
2132 	 * Disable EC wakeup on following systems to prevent periodic
2133 	 * wakeup from EC GPE.
2134 	 */
2135 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2136 		ec_no_wakeup = true;
2137 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2138 	}
2139 
2140 	/* Driver must be registered after acpi_ec_init_workqueues(). */
2141 	acpi_bus_register_driver(&acpi_ec_driver);
2142 
2143 	acpi_ec_ecdt_start();
2144 }
2145 
2146 /* EC driver currently not unloadable */
2147 #if 0
2148 static void __exit acpi_ec_exit(void)
2149 {
2150 
2151 	acpi_bus_unregister_driver(&acpi_ec_driver);
2152 	acpi_ec_destroy_workqueues();
2153 }
2154 #endif	/* 0 */
2155