xref: /linux/drivers/acpi/ec.c (revision d786bdf2a70545a868cd0b06b5603cd5a5fec011)
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_EVENT_HANDLER_INSTALLED,	/* Event handler installed */
96 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
97 	EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
98 	EC_FLAGS_STARTED,		/* Driver is started */
99 	EC_FLAGS_STOPPED,		/* Driver is stopped */
100 	EC_FLAGS_EVENTS_MASKED,		/* Events masked */
101 };
102 
103 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
104 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
105 
106 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
107 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
108 module_param(ec_delay, uint, 0644);
109 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
110 
111 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
112 module_param(ec_max_queries, uint, 0644);
113 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
114 
115 static bool ec_busy_polling __read_mostly;
116 module_param(ec_busy_polling, bool, 0644);
117 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
118 
119 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
120 module_param(ec_polling_guard, uint, 0644);
121 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
122 
123 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
124 
125 /*
126  * If the number of false interrupts per one transaction exceeds
127  * this threshold, will think there is a GPE storm happened and
128  * will disable the GPE for normal transaction.
129  */
130 static unsigned int ec_storm_threshold  __read_mostly = 8;
131 module_param(ec_storm_threshold, uint, 0644);
132 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
133 
134 static bool ec_freeze_events __read_mostly;
135 module_param(ec_freeze_events, bool, 0644);
136 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
137 
138 static bool ec_no_wakeup __read_mostly;
139 module_param(ec_no_wakeup, bool, 0644);
140 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
141 
142 struct acpi_ec_query_handler {
143 	struct list_head node;
144 	acpi_ec_query_func func;
145 	acpi_handle handle;
146 	void *data;
147 	u8 query_bit;
148 	struct kref kref;
149 };
150 
151 struct transaction {
152 	const u8 *wdata;
153 	u8 *rdata;
154 	unsigned short irq_count;
155 	u8 command;
156 	u8 wi;
157 	u8 ri;
158 	u8 wlen;
159 	u8 rlen;
160 	u8 flags;
161 };
162 
163 struct acpi_ec_query {
164 	struct transaction transaction;
165 	struct work_struct work;
166 	struct acpi_ec_query_handler *handler;
167 	struct acpi_ec *ec;
168 };
169 
170 static int acpi_ec_submit_query(struct acpi_ec *ec);
171 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
172 static void acpi_ec_event_handler(struct work_struct *work);
173 
174 struct acpi_ec *first_ec;
175 EXPORT_SYMBOL(first_ec);
176 
177 static struct acpi_ec *boot_ec;
178 static bool boot_ec_is_ecdt;
179 static struct workqueue_struct *ec_wq;
180 static struct workqueue_struct *ec_query_wq;
181 
182 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
183 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
184 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
185 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
186 
187 /* --------------------------------------------------------------------------
188  *                           Logging/Debugging
189  * -------------------------------------------------------------------------- */
190 
191 /*
192  * Splitters used by the developers to track the boundary of the EC
193  * handling processes.
194  */
195 #ifdef DEBUG
196 #define EC_DBG_SEP	" "
197 #define EC_DBG_DRV	"+++++"
198 #define EC_DBG_STM	"====="
199 #define EC_DBG_REQ	"*****"
200 #define EC_DBG_EVT	"#####"
201 #else
202 #define EC_DBG_SEP	""
203 #define EC_DBG_DRV
204 #define EC_DBG_STM
205 #define EC_DBG_REQ
206 #define EC_DBG_EVT
207 #endif
208 
209 #define ec_log_raw(fmt, ...) \
210 	pr_info(fmt "\n", ##__VA_ARGS__)
211 #define ec_dbg_raw(fmt, ...) \
212 	pr_debug(fmt "\n", ##__VA_ARGS__)
213 #define ec_log(filter, fmt, ...) \
214 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
215 #define ec_dbg(filter, fmt, ...) \
216 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
217 
218 #define ec_log_drv(fmt, ...) \
219 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
220 #define ec_dbg_drv(fmt, ...) \
221 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
222 #define ec_dbg_stm(fmt, ...) \
223 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
224 #define ec_dbg_req(fmt, ...) \
225 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
226 #define ec_dbg_evt(fmt, ...) \
227 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
228 #define ec_dbg_ref(ec, fmt, ...) \
229 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
230 
231 /* --------------------------------------------------------------------------
232  *                           Device Flags
233  * -------------------------------------------------------------------------- */
234 
235 static bool acpi_ec_started(struct acpi_ec *ec)
236 {
237 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
238 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
239 }
240 
241 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
242 {
243 	/*
244 	 * There is an OSPM early stage logic. During the early stages
245 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
246 	 * the EC transactions are allowed to be performed.
247 	 */
248 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
249 		return false;
250 	/*
251 	 * However, disabling the event handling is experimental for late
252 	 * stage (suspend), and is controlled by the boot parameter of
253 	 * "ec_freeze_events":
254 	 * 1. true:  The EC event handling is disabled before entering
255 	 *           the noirq stage.
256 	 * 2. false: The EC event handling is automatically disabled as
257 	 *           soon as the EC driver is stopped.
258 	 */
259 	if (ec_freeze_events)
260 		return acpi_ec_started(ec);
261 	else
262 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
263 }
264 
265 static bool acpi_ec_flushed(struct acpi_ec *ec)
266 {
267 	return ec->reference_count == 1;
268 }
269 
270 /* --------------------------------------------------------------------------
271  *                           EC Registers
272  * -------------------------------------------------------------------------- */
273 
274 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
275 {
276 	u8 x = inb(ec->command_addr);
277 
278 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
279 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
280 		   x,
281 		   !!(x & ACPI_EC_FLAG_SCI),
282 		   !!(x & ACPI_EC_FLAG_BURST),
283 		   !!(x & ACPI_EC_FLAG_CMD),
284 		   !!(x & ACPI_EC_FLAG_IBF),
285 		   !!(x & ACPI_EC_FLAG_OBF));
286 	return x;
287 }
288 
289 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
290 {
291 	u8 x = inb(ec->data_addr);
292 
293 	ec->timestamp = jiffies;
294 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
295 	return x;
296 }
297 
298 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
299 {
300 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
301 	outb(command, ec->command_addr);
302 	ec->timestamp = jiffies;
303 }
304 
305 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
306 {
307 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
308 	outb(data, ec->data_addr);
309 	ec->timestamp = jiffies;
310 }
311 
312 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
313 static const char *acpi_ec_cmd_string(u8 cmd)
314 {
315 	switch (cmd) {
316 	case 0x80:
317 		return "RD_EC";
318 	case 0x81:
319 		return "WR_EC";
320 	case 0x82:
321 		return "BE_EC";
322 	case 0x83:
323 		return "BD_EC";
324 	case 0x84:
325 		return "QR_EC";
326 	}
327 	return "UNKNOWN";
328 }
329 #else
330 #define acpi_ec_cmd_string(cmd)		"UNDEF"
331 #endif
332 
333 /* --------------------------------------------------------------------------
334  *                           GPE Registers
335  * -------------------------------------------------------------------------- */
336 
337 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
338 {
339 	acpi_event_status gpe_status = 0;
340 
341 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
342 	return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
343 }
344 
345 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
346 {
347 	if (open)
348 		acpi_enable_gpe(NULL, ec->gpe);
349 	else {
350 		BUG_ON(ec->reference_count < 1);
351 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
352 	}
353 	if (acpi_ec_gpe_status_set(ec)) {
354 		/*
355 		 * On some platforms, EN=1 writes cannot trigger GPE. So
356 		 * software need to manually trigger a pseudo GPE event on
357 		 * EN=1 writes.
358 		 */
359 		ec_dbg_raw("Polling quirk");
360 		advance_transaction(ec, false);
361 	}
362 }
363 
364 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
365 {
366 	if (close)
367 		acpi_disable_gpe(NULL, ec->gpe);
368 	else {
369 		BUG_ON(ec->reference_count < 1);
370 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
371 	}
372 }
373 
374 /* --------------------------------------------------------------------------
375  *                           Transaction Management
376  * -------------------------------------------------------------------------- */
377 
378 static void acpi_ec_submit_request(struct acpi_ec *ec)
379 {
380 	ec->reference_count++;
381 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
382 	    ec->gpe >= 0 && ec->reference_count == 1)
383 		acpi_ec_enable_gpe(ec, true);
384 }
385 
386 static void acpi_ec_complete_request(struct acpi_ec *ec)
387 {
388 	bool flushed = false;
389 
390 	ec->reference_count--;
391 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
392 	    ec->gpe >= 0 && ec->reference_count == 0)
393 		acpi_ec_disable_gpe(ec, true);
394 	flushed = acpi_ec_flushed(ec);
395 	if (flushed)
396 		wake_up(&ec->wait);
397 }
398 
399 static void acpi_ec_mask_events(struct acpi_ec *ec)
400 {
401 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
402 		if (ec->gpe >= 0)
403 			acpi_ec_disable_gpe(ec, false);
404 		else
405 			disable_irq_nosync(ec->irq);
406 
407 		ec_dbg_drv("Polling enabled");
408 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
409 	}
410 }
411 
412 static void acpi_ec_unmask_events(struct acpi_ec *ec)
413 {
414 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
415 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
416 		if (ec->gpe >= 0)
417 			acpi_ec_enable_gpe(ec, false);
418 		else
419 			enable_irq(ec->irq);
420 
421 		ec_dbg_drv("Polling disabled");
422 	}
423 }
424 
425 /*
426  * acpi_ec_submit_flushable_request() - Increase the reference count unless
427  *                                      the flush operation is not in
428  *                                      progress
429  * @ec: the EC device
430  *
431  * This function must be used before taking a new action that should hold
432  * the reference count.  If this function returns false, then the action
433  * must be discarded or it will prevent the flush operation from being
434  * completed.
435  */
436 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
437 {
438 	if (!acpi_ec_started(ec))
439 		return false;
440 	acpi_ec_submit_request(ec);
441 	return true;
442 }
443 
444 static void acpi_ec_submit_event(struct acpi_ec *ec)
445 {
446 	/*
447 	 * It is safe to mask the events here, because acpi_ec_close_event()
448 	 * will run at least once after this.
449 	 */
450 	acpi_ec_mask_events(ec);
451 	if (!acpi_ec_event_enabled(ec))
452 		return;
453 
454 	if (ec->event_state != EC_EVENT_READY)
455 		return;
456 
457 	ec_dbg_evt("Command(%s) submitted/blocked",
458 		   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
459 
460 	ec->event_state = EC_EVENT_IN_PROGRESS;
461 	/*
462 	 * If events_to_process is greater than 0 at this point, the while ()
463 	 * loop in acpi_ec_event_handler() is still running and incrementing
464 	 * events_to_process will cause it to invoke acpi_ec_submit_query() once
465 	 * more, so it is not necessary to queue up the event work to start the
466 	 * same loop again.
467 	 */
468 	if (ec->events_to_process++ > 0)
469 		return;
470 
471 	ec->events_in_progress++;
472 	queue_work(ec_wq, &ec->work);
473 }
474 
475 static void acpi_ec_complete_event(struct acpi_ec *ec)
476 {
477 	if (ec->event_state == EC_EVENT_IN_PROGRESS)
478 		ec->event_state = EC_EVENT_COMPLETE;
479 }
480 
481 static void acpi_ec_close_event(struct acpi_ec *ec)
482 {
483 	if (ec->event_state != EC_EVENT_READY)
484 		ec_dbg_evt("Command(%s) unblocked",
485 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
486 
487 	ec->event_state = EC_EVENT_READY;
488 	acpi_ec_unmask_events(ec);
489 }
490 
491 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
492 {
493 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
494 		ec_log_drv("event unblocked");
495 	/*
496 	 * Unconditionally invoke this once after enabling the event
497 	 * handling mechanism to detect the pending events.
498 	 */
499 	advance_transaction(ec, false);
500 }
501 
502 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
503 {
504 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
505 		ec_log_drv("event blocked");
506 }
507 
508 /*
509  * Process _Q events that might have accumulated in the EC.
510  * Run with locked ec mutex.
511  */
512 static void acpi_ec_clear(struct acpi_ec *ec)
513 {
514 	int i;
515 
516 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
517 		if (acpi_ec_submit_query(ec))
518 			break;
519 	}
520 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
521 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
522 	else
523 		pr_info("%d stale EC events cleared\n", i);
524 }
525 
526 static void acpi_ec_enable_event(struct acpi_ec *ec)
527 {
528 	unsigned long flags;
529 
530 	spin_lock_irqsave(&ec->lock, flags);
531 	if (acpi_ec_started(ec))
532 		__acpi_ec_enable_event(ec);
533 	spin_unlock_irqrestore(&ec->lock, flags);
534 
535 	/* Drain additional events if hardware requires that */
536 	if (EC_FLAGS_CLEAR_ON_RESUME)
537 		acpi_ec_clear(ec);
538 }
539 
540 #ifdef CONFIG_PM_SLEEP
541 static void __acpi_ec_flush_work(void)
542 {
543 	flush_workqueue(ec_wq); /* flush ec->work */
544 	flush_workqueue(ec_query_wq); /* flush queries */
545 }
546 
547 static void acpi_ec_disable_event(struct acpi_ec *ec)
548 {
549 	unsigned long flags;
550 
551 	spin_lock_irqsave(&ec->lock, flags);
552 	__acpi_ec_disable_event(ec);
553 	spin_unlock_irqrestore(&ec->lock, flags);
554 
555 	/*
556 	 * When ec_freeze_events is true, we need to flush events in
557 	 * the proper position before entering the noirq stage.
558 	 */
559 	__acpi_ec_flush_work();
560 }
561 
562 void acpi_ec_flush_work(void)
563 {
564 	/* Without ec_wq there is nothing to flush. */
565 	if (!ec_wq)
566 		return;
567 
568 	__acpi_ec_flush_work();
569 }
570 #endif /* CONFIG_PM_SLEEP */
571 
572 static bool acpi_ec_guard_event(struct acpi_ec *ec)
573 {
574 	unsigned long flags;
575 	bool guarded;
576 
577 	spin_lock_irqsave(&ec->lock, flags);
578 	/*
579 	 * If firmware SCI_EVT clearing timing is "event", we actually
580 	 * don't know when the SCI_EVT will be cleared by firmware after
581 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
582 	 * acceptable period.
583 	 *
584 	 * The guarding period is applicable if the event state is not
585 	 * EC_EVENT_READY, but otherwise if the current transaction is of the
586 	 * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
587 	 * and it should not be applied to let the transaction transition into
588 	 * the ACPI_EC_COMMAND_POLL state immediately.
589 	 */
590 	guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
591 		ec->event_state != EC_EVENT_READY &&
592 		(!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
593 	spin_unlock_irqrestore(&ec->lock, flags);
594 	return guarded;
595 }
596 
597 static int ec_transaction_polled(struct acpi_ec *ec)
598 {
599 	unsigned long flags;
600 	int ret = 0;
601 
602 	spin_lock_irqsave(&ec->lock, flags);
603 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
604 		ret = 1;
605 	spin_unlock_irqrestore(&ec->lock, flags);
606 	return ret;
607 }
608 
609 static int ec_transaction_completed(struct acpi_ec *ec)
610 {
611 	unsigned long flags;
612 	int ret = 0;
613 
614 	spin_lock_irqsave(&ec->lock, flags);
615 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
616 		ret = 1;
617 	spin_unlock_irqrestore(&ec->lock, flags);
618 	return ret;
619 }
620 
621 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
622 {
623 	ec->curr->flags |= flag;
624 
625 	if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
626 		return;
627 
628 	switch (ec_event_clearing) {
629 	case ACPI_EC_EVT_TIMING_STATUS:
630 		if (flag == ACPI_EC_COMMAND_POLL)
631 			acpi_ec_close_event(ec);
632 
633 		return;
634 
635 	case ACPI_EC_EVT_TIMING_QUERY:
636 		if (flag == ACPI_EC_COMMAND_COMPLETE)
637 			acpi_ec_close_event(ec);
638 
639 		return;
640 
641 	case ACPI_EC_EVT_TIMING_EVENT:
642 		if (flag == ACPI_EC_COMMAND_COMPLETE)
643 			acpi_ec_complete_event(ec);
644 	}
645 }
646 
647 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
648 {
649 	if (t->irq_count < ec_storm_threshold)
650 		++t->irq_count;
651 
652 	/* Trigger if the threshold is 0 too. */
653 	if (t->irq_count == ec_storm_threshold)
654 		acpi_ec_mask_events(ec);
655 }
656 
657 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
658 {
659 	struct transaction *t = ec->curr;
660 	bool wakeup = false;
661 	u8 status;
662 
663 	ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
664 
665 	/*
666 	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
667 	 * changes to always trigger a GPE interrupt.
668 	 *
669 	 * GPE STS is a W1C register, which means:
670 	 *
671 	 * 1. Software can clear it without worrying about clearing the other
672 	 *    GPEs' STS bits when the hardware sets them in parallel.
673 	 *
674 	 * 2. As long as software can ensure only clearing it when it is set,
675 	 *    hardware won't set it in parallel.
676 	 */
677 	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
678 		acpi_clear_gpe(NULL, ec->gpe);
679 
680 	status = acpi_ec_read_status(ec);
681 
682 	/*
683 	 * Another IRQ or a guarded polling mode advancement is detected,
684 	 * the next QR_EC submission is then allowed.
685 	 */
686 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
687 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
688 		    ec->event_state == EC_EVENT_COMPLETE)
689 			acpi_ec_close_event(ec);
690 
691 		if (!t)
692 			goto out;
693 	}
694 
695 	if (t->flags & ACPI_EC_COMMAND_POLL) {
696 		if (t->wlen > t->wi) {
697 			if (!(status & ACPI_EC_FLAG_IBF))
698 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
699 			else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
700 				acpi_ec_spurious_interrupt(ec, t);
701 		} else if (t->rlen > t->ri) {
702 			if (status & ACPI_EC_FLAG_OBF) {
703 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
704 				if (t->rlen == t->ri) {
705 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
706 					wakeup = true;
707 					if (t->command == ACPI_EC_COMMAND_QUERY)
708 						ec_dbg_evt("Command(%s) completed by hardware",
709 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
710 				}
711 			} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
712 				acpi_ec_spurious_interrupt(ec, t);
713 			}
714 		} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
715 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
716 			wakeup = true;
717 		}
718 	} else if (!(status & ACPI_EC_FLAG_IBF)) {
719 		acpi_ec_write_cmd(ec, t->command);
720 		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
721 	}
722 
723 out:
724 	if (status & ACPI_EC_FLAG_SCI)
725 		acpi_ec_submit_event(ec);
726 
727 	if (wakeup && interrupt)
728 		wake_up(&ec->wait);
729 }
730 
731 static void start_transaction(struct acpi_ec *ec)
732 {
733 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
734 	ec->curr->flags = 0;
735 }
736 
737 static int ec_guard(struct acpi_ec *ec)
738 {
739 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
740 	unsigned long timeout = ec->timestamp + guard;
741 
742 	/* Ensure guarding period before polling EC status */
743 	do {
744 		if (ec->busy_polling) {
745 			/* Perform busy polling */
746 			if (ec_transaction_completed(ec))
747 				return 0;
748 			udelay(jiffies_to_usecs(guard));
749 		} else {
750 			/*
751 			 * Perform wait polling
752 			 * 1. Wait the transaction to be completed by the
753 			 *    GPE handler after the transaction enters
754 			 *    ACPI_EC_COMMAND_POLL state.
755 			 * 2. A special guarding logic is also required
756 			 *    for event clearing mode "event" before the
757 			 *    transaction enters ACPI_EC_COMMAND_POLL
758 			 *    state.
759 			 */
760 			if (!ec_transaction_polled(ec) &&
761 			    !acpi_ec_guard_event(ec))
762 				break;
763 			if (wait_event_timeout(ec->wait,
764 					       ec_transaction_completed(ec),
765 					       guard))
766 				return 0;
767 		}
768 	} while (time_before(jiffies, timeout));
769 	return -ETIME;
770 }
771 
772 static int ec_poll(struct acpi_ec *ec)
773 {
774 	unsigned long flags;
775 	int repeat = 5; /* number of command restarts */
776 
777 	while (repeat--) {
778 		unsigned long delay = jiffies +
779 			msecs_to_jiffies(ec_delay);
780 		do {
781 			if (!ec_guard(ec))
782 				return 0;
783 			spin_lock_irqsave(&ec->lock, flags);
784 			advance_transaction(ec, false);
785 			spin_unlock_irqrestore(&ec->lock, flags);
786 		} while (time_before(jiffies, delay));
787 		pr_debug("controller reset, restart transaction\n");
788 		spin_lock_irqsave(&ec->lock, flags);
789 		start_transaction(ec);
790 		spin_unlock_irqrestore(&ec->lock, flags);
791 	}
792 	return -ETIME;
793 }
794 
795 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
796 					struct transaction *t)
797 {
798 	unsigned long tmp;
799 	int ret = 0;
800 
801 	/* start transaction */
802 	spin_lock_irqsave(&ec->lock, tmp);
803 	/* Enable GPE for command processing (IBF=0/OBF=1) */
804 	if (!acpi_ec_submit_flushable_request(ec)) {
805 		ret = -EINVAL;
806 		goto unlock;
807 	}
808 	ec_dbg_ref(ec, "Increase command");
809 	/* following two actions should be kept atomic */
810 	ec->curr = t;
811 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
812 	start_transaction(ec);
813 	spin_unlock_irqrestore(&ec->lock, tmp);
814 
815 	ret = ec_poll(ec);
816 
817 	spin_lock_irqsave(&ec->lock, tmp);
818 	if (t->irq_count == ec_storm_threshold)
819 		acpi_ec_unmask_events(ec);
820 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
821 	ec->curr = NULL;
822 	/* Disable GPE for command processing (IBF=0/OBF=1) */
823 	acpi_ec_complete_request(ec);
824 	ec_dbg_ref(ec, "Decrease command");
825 unlock:
826 	spin_unlock_irqrestore(&ec->lock, tmp);
827 	return ret;
828 }
829 
830 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
831 {
832 	int status;
833 	u32 glk;
834 
835 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
836 		return -EINVAL;
837 	if (t->rdata)
838 		memset(t->rdata, 0, t->rlen);
839 
840 	mutex_lock(&ec->mutex);
841 	if (ec->global_lock) {
842 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
843 		if (ACPI_FAILURE(status)) {
844 			status = -ENODEV;
845 			goto unlock;
846 		}
847 	}
848 
849 	status = acpi_ec_transaction_unlocked(ec, t);
850 
851 	if (ec->global_lock)
852 		acpi_release_global_lock(glk);
853 unlock:
854 	mutex_unlock(&ec->mutex);
855 	return status;
856 }
857 
858 static int acpi_ec_burst_enable(struct acpi_ec *ec)
859 {
860 	u8 d;
861 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
862 				.wdata = NULL, .rdata = &d,
863 				.wlen = 0, .rlen = 1};
864 
865 	return acpi_ec_transaction(ec, &t);
866 }
867 
868 static int acpi_ec_burst_disable(struct acpi_ec *ec)
869 {
870 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
871 				.wdata = NULL, .rdata = NULL,
872 				.wlen = 0, .rlen = 0};
873 
874 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
875 				acpi_ec_transaction(ec, &t) : 0;
876 }
877 
878 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
879 {
880 	int result;
881 	u8 d;
882 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
883 				.wdata = &address, .rdata = &d,
884 				.wlen = 1, .rlen = 1};
885 
886 	result = acpi_ec_transaction(ec, &t);
887 	*data = d;
888 	return result;
889 }
890 
891 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
892 {
893 	u8 wdata[2] = { address, data };
894 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
895 				.wdata = wdata, .rdata = NULL,
896 				.wlen = 2, .rlen = 0};
897 
898 	return acpi_ec_transaction(ec, &t);
899 }
900 
901 int ec_read(u8 addr, u8 *val)
902 {
903 	int err;
904 	u8 temp_data;
905 
906 	if (!first_ec)
907 		return -ENODEV;
908 
909 	err = acpi_ec_read(first_ec, addr, &temp_data);
910 
911 	if (!err) {
912 		*val = temp_data;
913 		return 0;
914 	}
915 	return err;
916 }
917 EXPORT_SYMBOL(ec_read);
918 
919 int ec_write(u8 addr, u8 val)
920 {
921 	int err;
922 
923 	if (!first_ec)
924 		return -ENODEV;
925 
926 	err = acpi_ec_write(first_ec, addr, val);
927 
928 	return err;
929 }
930 EXPORT_SYMBOL(ec_write);
931 
932 int ec_transaction(u8 command,
933 		   const u8 *wdata, unsigned wdata_len,
934 		   u8 *rdata, unsigned rdata_len)
935 {
936 	struct transaction t = {.command = command,
937 				.wdata = wdata, .rdata = rdata,
938 				.wlen = wdata_len, .rlen = rdata_len};
939 
940 	if (!first_ec)
941 		return -ENODEV;
942 
943 	return acpi_ec_transaction(first_ec, &t);
944 }
945 EXPORT_SYMBOL(ec_transaction);
946 
947 /* Get the handle to the EC device */
948 acpi_handle ec_get_handle(void)
949 {
950 	if (!first_ec)
951 		return NULL;
952 	return first_ec->handle;
953 }
954 EXPORT_SYMBOL(ec_get_handle);
955 
956 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
957 {
958 	unsigned long flags;
959 
960 	spin_lock_irqsave(&ec->lock, flags);
961 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
962 		ec_dbg_drv("Starting EC");
963 		/* Enable GPE for event processing (SCI_EVT=1) */
964 		if (!resuming) {
965 			acpi_ec_submit_request(ec);
966 			ec_dbg_ref(ec, "Increase driver");
967 		}
968 		ec_log_drv("EC started");
969 	}
970 	spin_unlock_irqrestore(&ec->lock, flags);
971 }
972 
973 static bool acpi_ec_stopped(struct acpi_ec *ec)
974 {
975 	unsigned long flags;
976 	bool flushed;
977 
978 	spin_lock_irqsave(&ec->lock, flags);
979 	flushed = acpi_ec_flushed(ec);
980 	spin_unlock_irqrestore(&ec->lock, flags);
981 	return flushed;
982 }
983 
984 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
985 {
986 	unsigned long flags;
987 
988 	spin_lock_irqsave(&ec->lock, flags);
989 	if (acpi_ec_started(ec)) {
990 		ec_dbg_drv("Stopping EC");
991 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
992 		spin_unlock_irqrestore(&ec->lock, flags);
993 		wait_event(ec->wait, acpi_ec_stopped(ec));
994 		spin_lock_irqsave(&ec->lock, flags);
995 		/* Disable GPE for event processing (SCI_EVT=1) */
996 		if (!suspending) {
997 			acpi_ec_complete_request(ec);
998 			ec_dbg_ref(ec, "Decrease driver");
999 		} else if (!ec_freeze_events)
1000 			__acpi_ec_disable_event(ec);
1001 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1002 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1003 		ec_log_drv("EC stopped");
1004 	}
1005 	spin_unlock_irqrestore(&ec->lock, flags);
1006 }
1007 
1008 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1009 {
1010 	unsigned long flags;
1011 
1012 	spin_lock_irqsave(&ec->lock, flags);
1013 	ec->busy_polling = true;
1014 	ec->polling_guard = 0;
1015 	ec_log_drv("interrupt blocked");
1016 	spin_unlock_irqrestore(&ec->lock, flags);
1017 }
1018 
1019 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1020 {
1021 	unsigned long flags;
1022 
1023 	spin_lock_irqsave(&ec->lock, flags);
1024 	ec->busy_polling = ec_busy_polling;
1025 	ec->polling_guard = ec_polling_guard;
1026 	ec_log_drv("interrupt unblocked");
1027 	spin_unlock_irqrestore(&ec->lock, flags);
1028 }
1029 
1030 void acpi_ec_block_transactions(void)
1031 {
1032 	struct acpi_ec *ec = first_ec;
1033 
1034 	if (!ec)
1035 		return;
1036 
1037 	mutex_lock(&ec->mutex);
1038 	/* Prevent transactions from being carried out */
1039 	acpi_ec_stop(ec, true);
1040 	mutex_unlock(&ec->mutex);
1041 }
1042 
1043 void acpi_ec_unblock_transactions(void)
1044 {
1045 	/*
1046 	 * Allow transactions to happen again (this function is called from
1047 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1048 	 */
1049 	if (first_ec)
1050 		acpi_ec_start(first_ec, true);
1051 }
1052 
1053 /* --------------------------------------------------------------------------
1054                                 Event Management
1055    -------------------------------------------------------------------------- */
1056 static struct acpi_ec_query_handler *
1057 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1058 {
1059 	struct acpi_ec_query_handler *handler;
1060 
1061 	mutex_lock(&ec->mutex);
1062 	list_for_each_entry(handler, &ec->list, node) {
1063 		if (value == handler->query_bit) {
1064 			kref_get(&handler->kref);
1065 			mutex_unlock(&ec->mutex);
1066 			return handler;
1067 		}
1068 	}
1069 	mutex_unlock(&ec->mutex);
1070 	return NULL;
1071 }
1072 
1073 static void acpi_ec_query_handler_release(struct kref *kref)
1074 {
1075 	struct acpi_ec_query_handler *handler =
1076 		container_of(kref, struct acpi_ec_query_handler, kref);
1077 
1078 	kfree(handler);
1079 }
1080 
1081 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1082 {
1083 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1084 }
1085 
1086 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1087 			      acpi_handle handle, acpi_ec_query_func func,
1088 			      void *data)
1089 {
1090 	struct acpi_ec_query_handler *handler =
1091 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1092 
1093 	if (!handler)
1094 		return -ENOMEM;
1095 
1096 	handler->query_bit = query_bit;
1097 	handler->handle = handle;
1098 	handler->func = func;
1099 	handler->data = data;
1100 	mutex_lock(&ec->mutex);
1101 	kref_init(&handler->kref);
1102 	list_add(&handler->node, &ec->list);
1103 	mutex_unlock(&ec->mutex);
1104 	return 0;
1105 }
1106 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1107 
1108 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1109 					  bool remove_all, u8 query_bit)
1110 {
1111 	struct acpi_ec_query_handler *handler, *tmp;
1112 	LIST_HEAD(free_list);
1113 
1114 	mutex_lock(&ec->mutex);
1115 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1116 		if (remove_all || query_bit == handler->query_bit) {
1117 			list_del_init(&handler->node);
1118 			list_add(&handler->node, &free_list);
1119 		}
1120 	}
1121 	mutex_unlock(&ec->mutex);
1122 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1123 		acpi_ec_put_query_handler(handler);
1124 }
1125 
1126 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1127 {
1128 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1129 }
1130 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1131 
1132 static void acpi_ec_event_processor(struct work_struct *work)
1133 {
1134 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1135 	struct acpi_ec_query_handler *handler = q->handler;
1136 	struct acpi_ec *ec = q->ec;
1137 
1138 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1139 
1140 	if (handler->func)
1141 		handler->func(handler->data);
1142 	else if (handler->handle)
1143 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1144 
1145 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1146 
1147 	spin_lock_irq(&ec->lock);
1148 	ec->queries_in_progress--;
1149 	spin_unlock_irq(&ec->lock);
1150 
1151 	acpi_ec_put_query_handler(handler);
1152 	kfree(q);
1153 }
1154 
1155 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1156 {
1157 	struct acpi_ec_query *q;
1158 	struct transaction *t;
1159 
1160 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1161 	if (!q)
1162 		return NULL;
1163 
1164 	INIT_WORK(&q->work, acpi_ec_event_processor);
1165 	t = &q->transaction;
1166 	t->command = ACPI_EC_COMMAND_QUERY;
1167 	t->rdata = pval;
1168 	t->rlen = 1;
1169 	q->ec = ec;
1170 	return q;
1171 }
1172 
1173 static int acpi_ec_submit_query(struct acpi_ec *ec)
1174 {
1175 	struct acpi_ec_query *q;
1176 	u8 value = 0;
1177 	int result;
1178 
1179 	q = acpi_ec_create_query(ec, &value);
1180 	if (!q)
1181 		return -ENOMEM;
1182 
1183 	/*
1184 	 * Query the EC to find out which _Qxx method we need to evaluate.
1185 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1186 	 * bit to be cleared (and thus clearing the interrupt source).
1187 	 */
1188 	result = acpi_ec_transaction(ec, &q->transaction);
1189 	if (result)
1190 		goto err_exit;
1191 
1192 	if (!value) {
1193 		result = -ENODATA;
1194 		goto err_exit;
1195 	}
1196 
1197 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1198 	if (!q->handler) {
1199 		result = -ENODATA;
1200 		goto err_exit;
1201 	}
1202 
1203 	/*
1204 	 * It is reported that _Qxx are evaluated in a parallel way on Windows:
1205 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1206 	 *
1207 	 * Put this log entry before queue_work() to make it appear in the log
1208 	 * before any other messages emitted during workqueue handling.
1209 	 */
1210 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1211 
1212 	spin_lock_irq(&ec->lock);
1213 
1214 	ec->queries_in_progress++;
1215 	queue_work(ec_query_wq, &q->work);
1216 
1217 	spin_unlock_irq(&ec->lock);
1218 
1219 	return 0;
1220 
1221 err_exit:
1222 	kfree(q);
1223 
1224 	return result;
1225 }
1226 
1227 static void acpi_ec_event_handler(struct work_struct *work)
1228 {
1229 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1230 
1231 	ec_dbg_evt("Event started");
1232 
1233 	spin_lock_irq(&ec->lock);
1234 
1235 	while (ec->events_to_process) {
1236 		spin_unlock_irq(&ec->lock);
1237 
1238 		acpi_ec_submit_query(ec);
1239 
1240 		spin_lock_irq(&ec->lock);
1241 
1242 		ec->events_to_process--;
1243 	}
1244 
1245 	/*
1246 	 * Before exit, make sure that the it will be possible to queue up the
1247 	 * event handling work again regardless of whether or not the query
1248 	 * queued up above is processed successfully.
1249 	 */
1250 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1251 		bool guard_timeout;
1252 
1253 		acpi_ec_complete_event(ec);
1254 
1255 		ec_dbg_evt("Event stopped");
1256 
1257 		spin_unlock_irq(&ec->lock);
1258 
1259 		guard_timeout = !!ec_guard(ec);
1260 
1261 		spin_lock_irq(&ec->lock);
1262 
1263 		/* Take care of SCI_EVT unless someone else is doing that. */
1264 		if (guard_timeout && !ec->curr)
1265 			advance_transaction(ec, false);
1266 	} else {
1267 		acpi_ec_close_event(ec);
1268 
1269 		ec_dbg_evt("Event stopped");
1270 	}
1271 
1272 	ec->events_in_progress--;
1273 
1274 	spin_unlock_irq(&ec->lock);
1275 }
1276 
1277 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1278 {
1279 	unsigned long flags;
1280 
1281 	spin_lock_irqsave(&ec->lock, flags);
1282 	advance_transaction(ec, true);
1283 	spin_unlock_irqrestore(&ec->lock, flags);
1284 }
1285 
1286 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1287 			       u32 gpe_number, void *data)
1288 {
1289 	acpi_ec_handle_interrupt(data);
1290 	return ACPI_INTERRUPT_HANDLED;
1291 }
1292 
1293 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1294 {
1295 	acpi_ec_handle_interrupt(data);
1296 	return IRQ_HANDLED;
1297 }
1298 
1299 /* --------------------------------------------------------------------------
1300  *                           Address Space Management
1301  * -------------------------------------------------------------------------- */
1302 
1303 static acpi_status
1304 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1305 		      u32 bits, u64 *value64,
1306 		      void *handler_context, void *region_context)
1307 {
1308 	struct acpi_ec *ec = handler_context;
1309 	int result = 0, i, bytes = bits / 8;
1310 	u8 *value = (u8 *)value64;
1311 
1312 	if ((address > 0xFF) || !value || !handler_context)
1313 		return AE_BAD_PARAMETER;
1314 
1315 	if (function != ACPI_READ && function != ACPI_WRITE)
1316 		return AE_BAD_PARAMETER;
1317 
1318 	if (ec->busy_polling || bits > 8)
1319 		acpi_ec_burst_enable(ec);
1320 
1321 	for (i = 0; i < bytes; ++i, ++address, ++value)
1322 		result = (function == ACPI_READ) ?
1323 			acpi_ec_read(ec, address, value) :
1324 			acpi_ec_write(ec, address, *value);
1325 
1326 	if (ec->busy_polling || bits > 8)
1327 		acpi_ec_burst_disable(ec);
1328 
1329 	switch (result) {
1330 	case -EINVAL:
1331 		return AE_BAD_PARAMETER;
1332 	case -ENODEV:
1333 		return AE_NOT_FOUND;
1334 	case -ETIME:
1335 		return AE_TIME;
1336 	default:
1337 		return AE_OK;
1338 	}
1339 }
1340 
1341 /* --------------------------------------------------------------------------
1342  *                             Driver Interface
1343  * -------------------------------------------------------------------------- */
1344 
1345 static acpi_status
1346 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1347 
1348 static void acpi_ec_free(struct acpi_ec *ec)
1349 {
1350 	if (first_ec == ec)
1351 		first_ec = NULL;
1352 	if (boot_ec == ec)
1353 		boot_ec = NULL;
1354 	kfree(ec);
1355 }
1356 
1357 static struct acpi_ec *acpi_ec_alloc(void)
1358 {
1359 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1360 
1361 	if (!ec)
1362 		return NULL;
1363 	mutex_init(&ec->mutex);
1364 	init_waitqueue_head(&ec->wait);
1365 	INIT_LIST_HEAD(&ec->list);
1366 	spin_lock_init(&ec->lock);
1367 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1368 	ec->timestamp = jiffies;
1369 	ec->busy_polling = true;
1370 	ec->polling_guard = 0;
1371 	ec->gpe = -1;
1372 	ec->irq = -1;
1373 	return ec;
1374 }
1375 
1376 static acpi_status
1377 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1378 			       void *context, void **return_value)
1379 {
1380 	char node_name[5];
1381 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1382 	struct acpi_ec *ec = context;
1383 	int value = 0;
1384 	acpi_status status;
1385 
1386 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1387 
1388 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1389 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1390 	return AE_OK;
1391 }
1392 
1393 static acpi_status
1394 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1395 {
1396 	acpi_status status;
1397 	unsigned long long tmp = 0;
1398 	struct acpi_ec *ec = context;
1399 
1400 	/* clear addr values, ec_parse_io_ports depend on it */
1401 	ec->command_addr = ec->data_addr = 0;
1402 
1403 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1404 				     ec_parse_io_ports, ec);
1405 	if (ACPI_FAILURE(status))
1406 		return status;
1407 	if (ec->data_addr == 0 || ec->command_addr == 0)
1408 		return AE_OK;
1409 
1410 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1411 		/*
1412 		 * Always inherit the GPE number setting from the ECDT
1413 		 * EC.
1414 		 */
1415 		ec->gpe = boot_ec->gpe;
1416 	} else {
1417 		/* Get GPE bit assignment (EC events). */
1418 		/* TODO: Add support for _GPE returning a package */
1419 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1420 		if (ACPI_SUCCESS(status))
1421 			ec->gpe = tmp;
1422 
1423 		/*
1424 		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1425 		 * platforms which use GpioInt instead of GPE.
1426 		 */
1427 	}
1428 	/* Use the global lock for all EC transactions? */
1429 	tmp = 0;
1430 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1431 	ec->global_lock = tmp;
1432 	ec->handle = handle;
1433 	return AE_CTRL_TERMINATE;
1434 }
1435 
1436 static bool install_gpe_event_handler(struct acpi_ec *ec)
1437 {
1438 	acpi_status status;
1439 
1440 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1441 					      ACPI_GPE_EDGE_TRIGGERED,
1442 					      &acpi_ec_gpe_handler, ec);
1443 	if (ACPI_FAILURE(status))
1444 		return false;
1445 
1446 	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1447 		acpi_ec_enable_gpe(ec, true);
1448 
1449 	return true;
1450 }
1451 
1452 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1453 {
1454 	return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1455 			   "ACPI EC", ec) >= 0;
1456 }
1457 
1458 /**
1459  * ec_install_handlers - Install service callbacks and register query methods.
1460  * @ec: Target EC.
1461  * @device: ACPI device object corresponding to @ec.
1462  *
1463  * Install a handler for the EC address space type unless it has been installed
1464  * already.  If @device is not NULL, also look for EC query methods in the
1465  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1466  * handler for the EC, if possible.
1467  *
1468  * Return:
1469  * -ENODEV if the address space handler cannot be installed, which means
1470  *  "unable to handle transactions",
1471  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1472  * or 0 (success) otherwise.
1473  */
1474 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1475 {
1476 	acpi_status status;
1477 
1478 	acpi_ec_start(ec, false);
1479 
1480 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1481 		acpi_ec_enter_noirq(ec);
1482 		status = acpi_install_address_space_handler(ec->handle,
1483 							    ACPI_ADR_SPACE_EC,
1484 							    &acpi_ec_space_handler,
1485 							    NULL, ec);
1486 		if (ACPI_FAILURE(status)) {
1487 			acpi_ec_stop(ec, false);
1488 			return -ENODEV;
1489 		}
1490 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1491 	}
1492 
1493 	if (!device)
1494 		return 0;
1495 
1496 	if (ec->gpe < 0) {
1497 		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1498 		int irq = acpi_dev_gpio_irq_get(device, 0);
1499 		/*
1500 		 * Bail out right away for deferred probing or complete the
1501 		 * initialization regardless of any other errors.
1502 		 */
1503 		if (irq == -EPROBE_DEFER)
1504 			return -EPROBE_DEFER;
1505 		else if (irq >= 0)
1506 			ec->irq = irq;
1507 	}
1508 
1509 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1510 		/* Find and register all query methods */
1511 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1512 				    acpi_ec_register_query_methods,
1513 				    NULL, ec, NULL);
1514 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1515 	}
1516 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1517 		bool ready = false;
1518 
1519 		if (ec->gpe >= 0)
1520 			ready = install_gpe_event_handler(ec);
1521 		else if (ec->irq >= 0)
1522 			ready = install_gpio_irq_event_handler(ec);
1523 
1524 		if (ready) {
1525 			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1526 			acpi_ec_leave_noirq(ec);
1527 		}
1528 		/*
1529 		 * Failures to install an event handler are not fatal, because
1530 		 * the EC can be polled for events.
1531 		 */
1532 	}
1533 	/* EC is fully operational, allow queries */
1534 	acpi_ec_enable_event(ec);
1535 
1536 	return 0;
1537 }
1538 
1539 static void ec_remove_handlers(struct acpi_ec *ec)
1540 {
1541 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1542 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1543 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1544 			pr_err("failed to remove space handler\n");
1545 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1546 	}
1547 
1548 	/*
1549 	 * Stops handling the EC transactions after removing the operation
1550 	 * region handler. This is required because _REG(DISCONNECT)
1551 	 * invoked during the removal can result in new EC transactions.
1552 	 *
1553 	 * Flushes the EC requests and thus disables the GPE before
1554 	 * removing the GPE handler. This is required by the current ACPICA
1555 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1556 	 * it is indicated but there is no way to handle it. So the drivers
1557 	 * must disable the GPEs prior to removing the GPE handlers.
1558 	 */
1559 	acpi_ec_stop(ec, false);
1560 
1561 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1562 		if (ec->gpe >= 0 &&
1563 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1564 				 &acpi_ec_gpe_handler)))
1565 			pr_err("failed to remove gpe handler\n");
1566 
1567 		if (ec->irq >= 0)
1568 			free_irq(ec->irq, ec);
1569 
1570 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1571 	}
1572 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1573 		acpi_ec_remove_query_handlers(ec, true, 0);
1574 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1575 	}
1576 }
1577 
1578 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1579 {
1580 	int ret;
1581 
1582 	ret = ec_install_handlers(ec, device);
1583 	if (ret)
1584 		return ret;
1585 
1586 	/* First EC capable of handling transactions */
1587 	if (!first_ec)
1588 		first_ec = ec;
1589 
1590 	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1591 		ec->data_addr);
1592 
1593 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1594 		if (ec->gpe >= 0)
1595 			pr_info("GPE=0x%x\n", ec->gpe);
1596 		else
1597 			pr_info("IRQ=%d\n", ec->irq);
1598 	}
1599 
1600 	return ret;
1601 }
1602 
1603 static int acpi_ec_add(struct acpi_device *device)
1604 {
1605 	struct acpi_ec *ec;
1606 	int ret;
1607 
1608 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1609 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1610 
1611 	if (boot_ec && (boot_ec->handle == device->handle ||
1612 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1613 		/* Fast path: this device corresponds to the boot EC. */
1614 		ec = boot_ec;
1615 	} else {
1616 		acpi_status status;
1617 
1618 		ec = acpi_ec_alloc();
1619 		if (!ec)
1620 			return -ENOMEM;
1621 
1622 		status = ec_parse_device(device->handle, 0, ec, NULL);
1623 		if (status != AE_CTRL_TERMINATE) {
1624 			ret = -EINVAL;
1625 			goto err;
1626 		}
1627 
1628 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1629 		    ec->data_addr == boot_ec->data_addr &&
1630 		    !EC_FLAGS_TRUST_DSDT_GPE) {
1631 			/*
1632 			 * Trust PNP0C09 namespace location rather than
1633 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1634 			 * because of ASUS quirks, so do not change
1635 			 * boot_ec->gpe to ec->gpe.
1636 			 */
1637 			boot_ec->handle = ec->handle;
1638 			acpi_handle_debug(ec->handle, "duplicated.\n");
1639 			acpi_ec_free(ec);
1640 			ec = boot_ec;
1641 		}
1642 	}
1643 
1644 	ret = acpi_ec_setup(ec, device);
1645 	if (ret)
1646 		goto err;
1647 
1648 	if (ec == boot_ec)
1649 		acpi_handle_info(boot_ec->handle,
1650 				 "Boot %s EC initialization complete\n",
1651 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1652 
1653 	acpi_handle_info(ec->handle,
1654 			 "EC: Used to handle transactions and events\n");
1655 
1656 	device->driver_data = ec;
1657 
1658 	ret = !!request_region(ec->data_addr, 1, "EC data");
1659 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1660 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1661 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1662 
1663 	/* Reprobe devices depending on the EC */
1664 	acpi_dev_clear_dependencies(device);
1665 
1666 	acpi_handle_debug(ec->handle, "enumerated.\n");
1667 	return 0;
1668 
1669 err:
1670 	if (ec != boot_ec)
1671 		acpi_ec_free(ec);
1672 
1673 	return ret;
1674 }
1675 
1676 static int acpi_ec_remove(struct acpi_device *device)
1677 {
1678 	struct acpi_ec *ec;
1679 
1680 	if (!device)
1681 		return -EINVAL;
1682 
1683 	ec = acpi_driver_data(device);
1684 	release_region(ec->data_addr, 1);
1685 	release_region(ec->command_addr, 1);
1686 	device->driver_data = NULL;
1687 	if (ec != boot_ec) {
1688 		ec_remove_handlers(ec);
1689 		acpi_ec_free(ec);
1690 	}
1691 	return 0;
1692 }
1693 
1694 static acpi_status
1695 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1696 {
1697 	struct acpi_ec *ec = context;
1698 
1699 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1700 		return AE_OK;
1701 
1702 	/*
1703 	 * The first address region returned is the data port, and
1704 	 * the second address region returned is the status/command
1705 	 * port.
1706 	 */
1707 	if (ec->data_addr == 0)
1708 		ec->data_addr = resource->data.io.minimum;
1709 	else if (ec->command_addr == 0)
1710 		ec->command_addr = resource->data.io.minimum;
1711 	else
1712 		return AE_CTRL_TERMINATE;
1713 
1714 	return AE_OK;
1715 }
1716 
1717 static const struct acpi_device_id ec_device_ids[] = {
1718 	{"PNP0C09", 0},
1719 	{ACPI_ECDT_HID, 0},
1720 	{"", 0},
1721 };
1722 
1723 /*
1724  * This function is not Windows-compatible as Windows never enumerates the
1725  * namespace EC before the main ACPI device enumeration process. It is
1726  * retained for historical reason and will be deprecated in the future.
1727  */
1728 void __init acpi_ec_dsdt_probe(void)
1729 {
1730 	struct acpi_ec *ec;
1731 	acpi_status status;
1732 	int ret;
1733 
1734 	/*
1735 	 * If a platform has ECDT, there is no need to proceed as the
1736 	 * following probe is not a part of the ACPI device enumeration,
1737 	 * executing _STA is not safe, and thus this probe may risk of
1738 	 * picking up an invalid EC device.
1739 	 */
1740 	if (boot_ec)
1741 		return;
1742 
1743 	ec = acpi_ec_alloc();
1744 	if (!ec)
1745 		return;
1746 
1747 	/*
1748 	 * At this point, the namespace is initialized, so start to find
1749 	 * the namespace objects.
1750 	 */
1751 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1752 	if (ACPI_FAILURE(status) || !ec->handle) {
1753 		acpi_ec_free(ec);
1754 		return;
1755 	}
1756 
1757 	/*
1758 	 * When the DSDT EC is available, always re-configure boot EC to
1759 	 * have _REG evaluated. _REG can only be evaluated after the
1760 	 * namespace initialization.
1761 	 * At this point, the GPE is not fully initialized, so do not to
1762 	 * handle the events.
1763 	 */
1764 	ret = acpi_ec_setup(ec, NULL);
1765 	if (ret) {
1766 		acpi_ec_free(ec);
1767 		return;
1768 	}
1769 
1770 	boot_ec = ec;
1771 
1772 	acpi_handle_info(ec->handle,
1773 			 "Boot DSDT EC used to handle transactions\n");
1774 }
1775 
1776 /*
1777  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1778  *
1779  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1780  * found a matching object in the namespace.
1781  *
1782  * Next, in case the DSDT EC is not functioning, it is still necessary to
1783  * provide a functional ECDT EC to handle events, so add an extra device object
1784  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1785  *
1786  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1787  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1788  */
1789 static void __init acpi_ec_ecdt_start(void)
1790 {
1791 	struct acpi_table_ecdt *ecdt_ptr;
1792 	acpi_handle handle;
1793 	acpi_status status;
1794 
1795 	/* Bail out if a matching EC has been found in the namespace. */
1796 	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1797 		return;
1798 
1799 	/* Look up the object pointed to from the ECDT in the namespace. */
1800 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1801 				(struct acpi_table_header **)&ecdt_ptr);
1802 	if (ACPI_FAILURE(status))
1803 		return;
1804 
1805 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1806 	if (ACPI_SUCCESS(status)) {
1807 		boot_ec->handle = handle;
1808 
1809 		/* Add a special ACPI device object to represent the boot EC. */
1810 		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1811 	}
1812 
1813 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1814 }
1815 
1816 /*
1817  * On some hardware it is necessary to clear events accumulated by the EC during
1818  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1819  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1820  *
1821  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1822  *
1823  * Ideally, the EC should also be instructed NOT to accumulate events during
1824  * sleep (which Windows seems to do somehow), but the interface to control this
1825  * behaviour is not known at this time.
1826  *
1827  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1828  * however it is very likely that other Samsung models are affected.
1829  *
1830  * On systems which don't accumulate _Q events during sleep, this extra check
1831  * should be harmless.
1832  */
1833 static int ec_clear_on_resume(const struct dmi_system_id *id)
1834 {
1835 	pr_debug("Detected system needing EC poll on resume.\n");
1836 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1837 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1838 	return 0;
1839 }
1840 
1841 /*
1842  * Some ECDTs contain wrong register addresses.
1843  * MSI MS-171F
1844  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1845  */
1846 static int ec_correct_ecdt(const struct dmi_system_id *id)
1847 {
1848 	pr_debug("Detected system needing ECDT address correction.\n");
1849 	EC_FLAGS_CORRECT_ECDT = 1;
1850 	return 0;
1851 }
1852 
1853 /*
1854  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1855  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1856  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1857  */
1858 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1859 {
1860 	pr_debug("Detected system needing DSDT GPE setting.\n");
1861 	EC_FLAGS_TRUST_DSDT_GPE = 1;
1862 	return 0;
1863 }
1864 
1865 /*
1866  * Some DSDTs contain wrong GPE setting.
1867  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1868  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1869  */
1870 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1871 {
1872 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1873 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1874 	return 0;
1875 }
1876 
1877 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1878 	{
1879 	ec_correct_ecdt, "MSI MS-171F", {
1880 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1881 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1882 	{
1883 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1884 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1885 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1886 	{
1887 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1888 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1889 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1890 	{
1891 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1892 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1893 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1894 	{
1895 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BA", {
1896 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1897 	DMI_MATCH(DMI_PRODUCT_NAME, "X505BA"),}, NULL},
1898 	{
1899 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BP", {
1900 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1901 	DMI_MATCH(DMI_PRODUCT_NAME, "X505BP"),}, NULL},
1902 	{
1903 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BA", {
1904 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1905 	DMI_MATCH(DMI_PRODUCT_NAME, "X542BA"),}, NULL},
1906 	{
1907 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BP", {
1908 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1909 	DMI_MATCH(DMI_PRODUCT_NAME, "X542BP"),}, NULL},
1910 	{
1911 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1912 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1913 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1914 	{
1915 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1916 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1917 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1918 	{
1919 	/* https://bugzilla.kernel.org/show_bug.cgi?id=209989 */
1920 	ec_honor_dsdt_gpe, "HP Pavilion Gaming Laptop 15-cx0xxx", {
1921 	DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1922 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),}, NULL},
1923 	{
1924 	ec_clear_on_resume, "Samsung hardware", {
1925 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1926 	{},
1927 };
1928 
1929 void __init acpi_ec_ecdt_probe(void)
1930 {
1931 	struct acpi_table_ecdt *ecdt_ptr;
1932 	struct acpi_ec *ec;
1933 	acpi_status status;
1934 	int ret;
1935 
1936 	/* Generate a boot ec context. */
1937 	dmi_check_system(ec_dmi_table);
1938 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1939 				(struct acpi_table_header **)&ecdt_ptr);
1940 	if (ACPI_FAILURE(status))
1941 		return;
1942 
1943 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1944 		/*
1945 		 * Asus X50GL:
1946 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1947 		 */
1948 		goto out;
1949 	}
1950 
1951 	ec = acpi_ec_alloc();
1952 	if (!ec)
1953 		goto out;
1954 
1955 	if (EC_FLAGS_CORRECT_ECDT) {
1956 		ec->command_addr = ecdt_ptr->data.address;
1957 		ec->data_addr = ecdt_ptr->control.address;
1958 	} else {
1959 		ec->command_addr = ecdt_ptr->control.address;
1960 		ec->data_addr = ecdt_ptr->data.address;
1961 	}
1962 
1963 	/*
1964 	 * Ignore the GPE value on Reduced Hardware platforms.
1965 	 * Some products have this set to an erroneous value.
1966 	 */
1967 	if (!acpi_gbl_reduced_hardware)
1968 		ec->gpe = ecdt_ptr->gpe;
1969 
1970 	ec->handle = ACPI_ROOT_OBJECT;
1971 
1972 	/*
1973 	 * At this point, the namespace is not initialized, so do not find
1974 	 * the namespace objects, or handle the events.
1975 	 */
1976 	ret = acpi_ec_setup(ec, NULL);
1977 	if (ret) {
1978 		acpi_ec_free(ec);
1979 		goto out;
1980 	}
1981 
1982 	boot_ec = ec;
1983 	boot_ec_is_ecdt = true;
1984 
1985 	pr_info("Boot ECDT EC used to handle transactions\n");
1986 
1987 out:
1988 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1989 }
1990 
1991 #ifdef CONFIG_PM_SLEEP
1992 static int acpi_ec_suspend(struct device *dev)
1993 {
1994 	struct acpi_ec *ec =
1995 		acpi_driver_data(to_acpi_device(dev));
1996 
1997 	if (!pm_suspend_no_platform() && ec_freeze_events)
1998 		acpi_ec_disable_event(ec);
1999 	return 0;
2000 }
2001 
2002 static int acpi_ec_suspend_noirq(struct device *dev)
2003 {
2004 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2005 
2006 	/*
2007 	 * The SCI handler doesn't run at this point, so the GPE can be
2008 	 * masked at the low level without side effects.
2009 	 */
2010 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2011 	    ec->gpe >= 0 && ec->reference_count >= 1)
2012 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2013 
2014 	acpi_ec_enter_noirq(ec);
2015 
2016 	return 0;
2017 }
2018 
2019 static int acpi_ec_resume_noirq(struct device *dev)
2020 {
2021 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2022 
2023 	acpi_ec_leave_noirq(ec);
2024 
2025 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2026 	    ec->gpe >= 0 && ec->reference_count >= 1)
2027 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2028 
2029 	return 0;
2030 }
2031 
2032 static int acpi_ec_resume(struct device *dev)
2033 {
2034 	struct acpi_ec *ec =
2035 		acpi_driver_data(to_acpi_device(dev));
2036 
2037 	acpi_ec_enable_event(ec);
2038 	return 0;
2039 }
2040 
2041 void acpi_ec_mark_gpe_for_wake(void)
2042 {
2043 	if (first_ec && !ec_no_wakeup)
2044 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2045 }
2046 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2047 
2048 void acpi_ec_set_gpe_wake_mask(u8 action)
2049 {
2050 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2051 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2052 }
2053 
2054 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2055 {
2056 	return ec->events_in_progress + ec->queries_in_progress > 0;
2057 }
2058 
2059 bool acpi_ec_dispatch_gpe(void)
2060 {
2061 	bool work_in_progress = false;
2062 
2063 	if (!first_ec)
2064 		return acpi_any_gpe_status_set(U32_MAX);
2065 
2066 	/*
2067 	 * Report wakeup if the status bit is set for any enabled GPE other
2068 	 * than the EC one.
2069 	 */
2070 	if (acpi_any_gpe_status_set(first_ec->gpe))
2071 		return true;
2072 
2073 	/*
2074 	 * Cancel the SCI wakeup and process all pending events in case there
2075 	 * are any wakeup ones in there.
2076 	 *
2077 	 * Note that if any non-EC GPEs are active at this point, the SCI will
2078 	 * retrigger after the rearming in acpi_s2idle_wake(), so no events
2079 	 * should be missed by canceling the wakeup here.
2080 	 */
2081 	pm_system_cancel_wakeup();
2082 
2083 	/*
2084 	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2085 	 * to allow the caller to process events properly after that.
2086 	 */
2087 	spin_lock_irq(&first_ec->lock);
2088 
2089 	if (acpi_ec_gpe_status_set(first_ec)) {
2090 		pm_pr_dbg("ACPI EC GPE status set\n");
2091 
2092 		advance_transaction(first_ec, false);
2093 		work_in_progress = acpi_ec_work_in_progress(first_ec);
2094 	}
2095 
2096 	spin_unlock_irq(&first_ec->lock);
2097 
2098 	if (!work_in_progress)
2099 		return false;
2100 
2101 	pm_pr_dbg("ACPI EC GPE dispatched\n");
2102 
2103 	/* Drain EC work. */
2104 	do {
2105 		acpi_ec_flush_work();
2106 
2107 		pm_pr_dbg("ACPI EC work flushed\n");
2108 
2109 		spin_lock_irq(&first_ec->lock);
2110 
2111 		work_in_progress = acpi_ec_work_in_progress(first_ec);
2112 
2113 		spin_unlock_irq(&first_ec->lock);
2114 	} while (work_in_progress && !pm_wakeup_pending());
2115 
2116 	return false;
2117 }
2118 #endif /* CONFIG_PM_SLEEP */
2119 
2120 static const struct dev_pm_ops acpi_ec_pm = {
2121 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2122 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2123 };
2124 
2125 static int param_set_event_clearing(const char *val,
2126 				    const struct kernel_param *kp)
2127 {
2128 	int result = 0;
2129 
2130 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2131 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2132 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2133 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2134 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2135 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2136 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2137 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2138 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2139 	} else
2140 		result = -EINVAL;
2141 	return result;
2142 }
2143 
2144 static int param_get_event_clearing(char *buffer,
2145 				    const struct kernel_param *kp)
2146 {
2147 	switch (ec_event_clearing) {
2148 	case ACPI_EC_EVT_TIMING_STATUS:
2149 		return sprintf(buffer, "status\n");
2150 	case ACPI_EC_EVT_TIMING_QUERY:
2151 		return sprintf(buffer, "query\n");
2152 	case ACPI_EC_EVT_TIMING_EVENT:
2153 		return sprintf(buffer, "event\n");
2154 	default:
2155 		return sprintf(buffer, "invalid\n");
2156 	}
2157 	return 0;
2158 }
2159 
2160 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2161 		  NULL, 0644);
2162 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2163 
2164 static struct acpi_driver acpi_ec_driver = {
2165 	.name = "ec",
2166 	.class = ACPI_EC_CLASS,
2167 	.ids = ec_device_ids,
2168 	.ops = {
2169 		.add = acpi_ec_add,
2170 		.remove = acpi_ec_remove,
2171 		},
2172 	.drv.pm = &acpi_ec_pm,
2173 };
2174 
2175 static void acpi_ec_destroy_workqueues(void)
2176 {
2177 	if (ec_wq) {
2178 		destroy_workqueue(ec_wq);
2179 		ec_wq = NULL;
2180 	}
2181 	if (ec_query_wq) {
2182 		destroy_workqueue(ec_query_wq);
2183 		ec_query_wq = NULL;
2184 	}
2185 }
2186 
2187 static int acpi_ec_init_workqueues(void)
2188 {
2189 	if (!ec_wq)
2190 		ec_wq = alloc_ordered_workqueue("kec", 0);
2191 
2192 	if (!ec_query_wq)
2193 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2194 
2195 	if (!ec_wq || !ec_query_wq) {
2196 		acpi_ec_destroy_workqueues();
2197 		return -ENODEV;
2198 	}
2199 	return 0;
2200 }
2201 
2202 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2203 	{
2204 		.ident = "Thinkpad X1 Carbon 6th",
2205 		.matches = {
2206 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2207 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2208 		},
2209 	},
2210 	{
2211 		.ident = "ThinkPad X1 Carbon 6th",
2212 		.matches = {
2213 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2214 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2215 		},
2216 	},
2217 	{
2218 		.ident = "ThinkPad X1 Yoga 3rd",
2219 		.matches = {
2220 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2221 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2222 		},
2223 	},
2224 	{
2225 		.ident = "HP ZHAN 66 Pro",
2226 		.matches = {
2227 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2228 			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2229 		},
2230 	},
2231 	{ },
2232 };
2233 
2234 void __init acpi_ec_init(void)
2235 {
2236 	int result;
2237 
2238 	result = acpi_ec_init_workqueues();
2239 	if (result)
2240 		return;
2241 
2242 	/*
2243 	 * Disable EC wakeup on following systems to prevent periodic
2244 	 * wakeup from EC GPE.
2245 	 */
2246 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2247 		ec_no_wakeup = true;
2248 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2249 	}
2250 
2251 	/* Driver must be registered after acpi_ec_init_workqueues(). */
2252 	acpi_bus_register_driver(&acpi_ec_driver);
2253 
2254 	acpi_ec_ecdt_start();
2255 }
2256 
2257 /* EC driver currently not unloadable */
2258 #if 0
2259 static void __exit acpi_ec_exit(void)
2260 {
2261 
2262 	acpi_bus_unregister_driver(&acpi_ec_driver);
2263 	acpi_ec_destroy_workqueues();
2264 }
2265 #endif	/* 0 */
2266