xref: /openbmc/linux/drivers/acpi/ec.c (revision d9679d00)
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;
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;
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_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
187 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
188 
189 /* --------------------------------------------------------------------------
190  *                           Logging/Debugging
191  * -------------------------------------------------------------------------- */
192 
193 /*
194  * Splitters used by the developers to track the boundary of the EC
195  * handling processes.
196  */
197 #ifdef DEBUG
198 #define EC_DBG_SEP	" "
199 #define EC_DBG_DRV	"+++++"
200 #define EC_DBG_STM	"====="
201 #define EC_DBG_REQ	"*****"
202 #define EC_DBG_EVT	"#####"
203 #else
204 #define EC_DBG_SEP	""
205 #define EC_DBG_DRV
206 #define EC_DBG_STM
207 #define EC_DBG_REQ
208 #define EC_DBG_EVT
209 #endif
210 
211 #define ec_log_raw(fmt, ...) \
212 	pr_info(fmt "\n", ##__VA_ARGS__)
213 #define ec_dbg_raw(fmt, ...) \
214 	pr_debug(fmt "\n", ##__VA_ARGS__)
215 #define ec_log(filter, fmt, ...) \
216 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
217 #define ec_dbg(filter, fmt, ...) \
218 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
219 
220 #define ec_log_drv(fmt, ...) \
221 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
222 #define ec_dbg_drv(fmt, ...) \
223 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
224 #define ec_dbg_stm(fmt, ...) \
225 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
226 #define ec_dbg_req(fmt, ...) \
227 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
228 #define ec_dbg_evt(fmt, ...) \
229 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
230 #define ec_dbg_ref(ec, fmt, ...) \
231 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
232 
233 /* --------------------------------------------------------------------------
234  *                           Device Flags
235  * -------------------------------------------------------------------------- */
236 
237 static bool acpi_ec_started(struct acpi_ec *ec)
238 {
239 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
240 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
241 }
242 
243 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
244 {
245 	/*
246 	 * There is an OSPM early stage logic. During the early stages
247 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
248 	 * the EC transactions are allowed to be performed.
249 	 */
250 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
251 		return false;
252 	/*
253 	 * However, disabling the event handling is experimental for late
254 	 * stage (suspend), and is controlled by the boot parameter of
255 	 * "ec_freeze_events":
256 	 * 1. true:  The EC event handling is disabled before entering
257 	 *           the noirq stage.
258 	 * 2. false: The EC event handling is automatically disabled as
259 	 *           soon as the EC driver is stopped.
260 	 */
261 	if (ec_freeze_events)
262 		return acpi_ec_started(ec);
263 	else
264 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
265 }
266 
267 static bool acpi_ec_flushed(struct acpi_ec *ec)
268 {
269 	return ec->reference_count == 1;
270 }
271 
272 /* --------------------------------------------------------------------------
273  *                           EC Registers
274  * -------------------------------------------------------------------------- */
275 
276 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
277 {
278 	u8 x = inb(ec->command_addr);
279 
280 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
281 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
282 		   x,
283 		   !!(x & ACPI_EC_FLAG_SCI),
284 		   !!(x & ACPI_EC_FLAG_BURST),
285 		   !!(x & ACPI_EC_FLAG_CMD),
286 		   !!(x & ACPI_EC_FLAG_IBF),
287 		   !!(x & ACPI_EC_FLAG_OBF));
288 	return x;
289 }
290 
291 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
292 {
293 	u8 x = inb(ec->data_addr);
294 
295 	ec->timestamp = jiffies;
296 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
297 	return x;
298 }
299 
300 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
301 {
302 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
303 	outb(command, ec->command_addr);
304 	ec->timestamp = jiffies;
305 }
306 
307 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
308 {
309 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
310 	outb(data, ec->data_addr);
311 	ec->timestamp = jiffies;
312 }
313 
314 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
315 static const char *acpi_ec_cmd_string(u8 cmd)
316 {
317 	switch (cmd) {
318 	case 0x80:
319 		return "RD_EC";
320 	case 0x81:
321 		return "WR_EC";
322 	case 0x82:
323 		return "BE_EC";
324 	case 0x83:
325 		return "BD_EC";
326 	case 0x84:
327 		return "QR_EC";
328 	}
329 	return "UNKNOWN";
330 }
331 #else
332 #define acpi_ec_cmd_string(cmd)		"UNDEF"
333 #endif
334 
335 /* --------------------------------------------------------------------------
336  *                           GPE Registers
337  * -------------------------------------------------------------------------- */
338 
339 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
340 {
341 	acpi_event_status gpe_status = 0;
342 
343 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
344 	return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
345 }
346 
347 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
348 {
349 	if (open)
350 		acpi_enable_gpe(NULL, ec->gpe);
351 	else {
352 		BUG_ON(ec->reference_count < 1);
353 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
354 	}
355 	if (acpi_ec_gpe_status_set(ec)) {
356 		/*
357 		 * On some platforms, EN=1 writes cannot trigger GPE. So
358 		 * software need to manually trigger a pseudo GPE event on
359 		 * EN=1 writes.
360 		 */
361 		ec_dbg_raw("Polling quirk");
362 		advance_transaction(ec, false);
363 	}
364 }
365 
366 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
367 {
368 	if (close)
369 		acpi_disable_gpe(NULL, ec->gpe);
370 	else {
371 		BUG_ON(ec->reference_count < 1);
372 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
373 	}
374 }
375 
376 /* --------------------------------------------------------------------------
377  *                           Transaction Management
378  * -------------------------------------------------------------------------- */
379 
380 static void acpi_ec_submit_request(struct acpi_ec *ec)
381 {
382 	ec->reference_count++;
383 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
384 	    ec->gpe >= 0 && ec->reference_count == 1)
385 		acpi_ec_enable_gpe(ec, true);
386 }
387 
388 static void acpi_ec_complete_request(struct acpi_ec *ec)
389 {
390 	bool flushed = false;
391 
392 	ec->reference_count--;
393 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
394 	    ec->gpe >= 0 && ec->reference_count == 0)
395 		acpi_ec_disable_gpe(ec, true);
396 	flushed = acpi_ec_flushed(ec);
397 	if (flushed)
398 		wake_up(&ec->wait);
399 }
400 
401 static void acpi_ec_mask_events(struct acpi_ec *ec)
402 {
403 	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
404 		if (ec->gpe >= 0)
405 			acpi_ec_disable_gpe(ec, false);
406 		else
407 			disable_irq_nosync(ec->irq);
408 
409 		ec_dbg_drv("Polling enabled");
410 		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
411 	}
412 }
413 
414 static void acpi_ec_unmask_events(struct acpi_ec *ec)
415 {
416 	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
417 		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
418 		if (ec->gpe >= 0)
419 			acpi_ec_enable_gpe(ec, false);
420 		else
421 			enable_irq(ec->irq);
422 
423 		ec_dbg_drv("Polling disabled");
424 	}
425 }
426 
427 /*
428  * acpi_ec_submit_flushable_request() - Increase the reference count unless
429  *                                      the flush operation is not in
430  *                                      progress
431  * @ec: the EC device
432  *
433  * This function must be used before taking a new action that should hold
434  * the reference count.  If this function returns false, then the action
435  * must be discarded or it will prevent the flush operation from being
436  * completed.
437  */
438 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
439 {
440 	if (!acpi_ec_started(ec))
441 		return false;
442 	acpi_ec_submit_request(ec);
443 	return true;
444 }
445 
446 static void acpi_ec_submit_query(struct acpi_ec *ec)
447 {
448 	acpi_ec_mask_events(ec);
449 	if (!acpi_ec_event_enabled(ec))
450 		return;
451 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
452 		ec_dbg_evt("Command(%s) submitted/blocked",
453 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
454 		ec->nr_pending_queries++;
455 		queue_work(ec_wq, &ec->work);
456 	}
457 }
458 
459 static void acpi_ec_complete_query(struct acpi_ec *ec)
460 {
461 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
462 		ec_dbg_evt("Command(%s) unblocked",
463 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
464 	acpi_ec_unmask_events(ec);
465 }
466 
467 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
468 {
469 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
470 		ec_log_drv("event unblocked");
471 	/*
472 	 * Unconditionally invoke this once after enabling the event
473 	 * handling mechanism to detect the pending events.
474 	 */
475 	advance_transaction(ec, false);
476 }
477 
478 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
479 {
480 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
481 		ec_log_drv("event blocked");
482 }
483 
484 /*
485  * Process _Q events that might have accumulated in the EC.
486  * Run with locked ec mutex.
487  */
488 static void acpi_ec_clear(struct acpi_ec *ec)
489 {
490 	int i, status;
491 	u8 value = 0;
492 
493 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
494 		status = acpi_ec_query(ec, &value);
495 		if (status || !value)
496 			break;
497 	}
498 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
499 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
500 	else
501 		pr_info("%d stale EC events cleared\n", i);
502 }
503 
504 static void acpi_ec_enable_event(struct acpi_ec *ec)
505 {
506 	unsigned long flags;
507 
508 	spin_lock_irqsave(&ec->lock, flags);
509 	if (acpi_ec_started(ec))
510 		__acpi_ec_enable_event(ec);
511 	spin_unlock_irqrestore(&ec->lock, flags);
512 
513 	/* Drain additional events if hardware requires that */
514 	if (EC_FLAGS_CLEAR_ON_RESUME)
515 		acpi_ec_clear(ec);
516 }
517 
518 #ifdef CONFIG_PM_SLEEP
519 static void __acpi_ec_flush_work(void)
520 {
521 	drain_workqueue(ec_wq); /* flush ec->work */
522 	flush_workqueue(ec_query_wq); /* flush queries */
523 }
524 
525 static void acpi_ec_disable_event(struct acpi_ec *ec)
526 {
527 	unsigned long flags;
528 
529 	spin_lock_irqsave(&ec->lock, flags);
530 	__acpi_ec_disable_event(ec);
531 	spin_unlock_irqrestore(&ec->lock, flags);
532 
533 	/*
534 	 * When ec_freeze_events is true, we need to flush events in
535 	 * the proper position before entering the noirq stage.
536 	 */
537 	__acpi_ec_flush_work();
538 }
539 
540 void acpi_ec_flush_work(void)
541 {
542 	/* Without ec_wq there is nothing to flush. */
543 	if (!ec_wq)
544 		return;
545 
546 	__acpi_ec_flush_work();
547 }
548 #endif /* CONFIG_PM_SLEEP */
549 
550 static bool acpi_ec_guard_event(struct acpi_ec *ec)
551 {
552 	bool guarded = true;
553 	unsigned long flags;
554 
555 	spin_lock_irqsave(&ec->lock, flags);
556 	/*
557 	 * If firmware SCI_EVT clearing timing is "event", we actually
558 	 * don't know when the SCI_EVT will be cleared by firmware after
559 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
560 	 * acceptable period.
561 	 *
562 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
563 	 * flagged, which means SCI_EVT check has just been performed.
564 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
565 	 * guarding should have already been performed (via
566 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
567 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
568 	 * ACPI_EC_COMMAND_POLL state immediately.
569 	 */
570 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
571 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
572 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
573 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
574 		guarded = false;
575 	spin_unlock_irqrestore(&ec->lock, flags);
576 	return guarded;
577 }
578 
579 static int ec_transaction_polled(struct acpi_ec *ec)
580 {
581 	unsigned long flags;
582 	int ret = 0;
583 
584 	spin_lock_irqsave(&ec->lock, flags);
585 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
586 		ret = 1;
587 	spin_unlock_irqrestore(&ec->lock, flags);
588 	return ret;
589 }
590 
591 static int ec_transaction_completed(struct acpi_ec *ec)
592 {
593 	unsigned long flags;
594 	int ret = 0;
595 
596 	spin_lock_irqsave(&ec->lock, flags);
597 	if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
598 		ret = 1;
599 	spin_unlock_irqrestore(&ec->lock, flags);
600 	return ret;
601 }
602 
603 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
604 {
605 	ec->curr->flags |= flag;
606 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
607 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
608 		    flag == ACPI_EC_COMMAND_POLL)
609 			acpi_ec_complete_query(ec);
610 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
611 		    flag == ACPI_EC_COMMAND_COMPLETE)
612 			acpi_ec_complete_query(ec);
613 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
614 		    flag == ACPI_EC_COMMAND_COMPLETE)
615 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
616 	}
617 }
618 
619 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
620 {
621 	if (t->irq_count < ec_storm_threshold)
622 		++t->irq_count;
623 
624 	/* Trigger if the threshold is 0 too. */
625 	if (t->irq_count == ec_storm_threshold)
626 		acpi_ec_mask_events(ec);
627 }
628 
629 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
630 {
631 	struct transaction *t = ec->curr;
632 	bool wakeup = false;
633 	u8 status;
634 
635 	ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
636 
637 	/*
638 	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
639 	 * changes to always trigger a GPE interrupt.
640 	 *
641 	 * GPE STS is a W1C register, which means:
642 	 *
643 	 * 1. Software can clear it without worrying about clearing the other
644 	 *    GPEs' STS bits when the hardware sets them in parallel.
645 	 *
646 	 * 2. As long as software can ensure only clearing it when it is set,
647 	 *    hardware won't set it in parallel.
648 	 */
649 	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
650 		acpi_clear_gpe(NULL, ec->gpe);
651 
652 	status = acpi_ec_read_status(ec);
653 
654 	/*
655 	 * Another IRQ or a guarded polling mode advancement is detected,
656 	 * the next QR_EC submission is then allowed.
657 	 */
658 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
659 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
660 		    (!ec->nr_pending_queries ||
661 		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
662 			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
663 			acpi_ec_complete_query(ec);
664 		}
665 		if (!t)
666 			goto out;
667 	}
668 
669 	if (t->flags & ACPI_EC_COMMAND_POLL) {
670 		if (t->wlen > t->wi) {
671 			if (!(status & ACPI_EC_FLAG_IBF))
672 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
673 			else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
674 				acpi_ec_spurious_interrupt(ec, t);
675 		} else if (t->rlen > t->ri) {
676 			if (status & ACPI_EC_FLAG_OBF) {
677 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
678 				if (t->rlen == t->ri) {
679 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
680 					wakeup = true;
681 					if (t->command == ACPI_EC_COMMAND_QUERY)
682 						ec_dbg_evt("Command(%s) completed by hardware",
683 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
684 				}
685 			} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
686 				acpi_ec_spurious_interrupt(ec, t);
687 			}
688 		} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
689 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
690 			wakeup = true;
691 		}
692 	} else if (!(status & ACPI_EC_FLAG_IBF)) {
693 		acpi_ec_write_cmd(ec, t->command);
694 		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
695 	}
696 
697 out:
698 	if (status & ACPI_EC_FLAG_SCI)
699 		acpi_ec_submit_query(ec);
700 
701 	if (wakeup && interrupt)
702 		wake_up(&ec->wait);
703 }
704 
705 static void start_transaction(struct acpi_ec *ec)
706 {
707 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
708 	ec->curr->flags = 0;
709 }
710 
711 static int ec_guard(struct acpi_ec *ec)
712 {
713 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
714 	unsigned long timeout = ec->timestamp + guard;
715 
716 	/* Ensure guarding period before polling EC status */
717 	do {
718 		if (ec->busy_polling) {
719 			/* Perform busy polling */
720 			if (ec_transaction_completed(ec))
721 				return 0;
722 			udelay(jiffies_to_usecs(guard));
723 		} else {
724 			/*
725 			 * Perform wait polling
726 			 * 1. Wait the transaction to be completed by the
727 			 *    GPE handler after the transaction enters
728 			 *    ACPI_EC_COMMAND_POLL state.
729 			 * 2. A special guarding logic is also required
730 			 *    for event clearing mode "event" before the
731 			 *    transaction enters ACPI_EC_COMMAND_POLL
732 			 *    state.
733 			 */
734 			if (!ec_transaction_polled(ec) &&
735 			    !acpi_ec_guard_event(ec))
736 				break;
737 			if (wait_event_timeout(ec->wait,
738 					       ec_transaction_completed(ec),
739 					       guard))
740 				return 0;
741 		}
742 	} while (time_before(jiffies, timeout));
743 	return -ETIME;
744 }
745 
746 static int ec_poll(struct acpi_ec *ec)
747 {
748 	unsigned long flags;
749 	int repeat = 5; /* number of command restarts */
750 
751 	while (repeat--) {
752 		unsigned long delay = jiffies +
753 			msecs_to_jiffies(ec_delay);
754 		do {
755 			if (!ec_guard(ec))
756 				return 0;
757 			spin_lock_irqsave(&ec->lock, flags);
758 			advance_transaction(ec, false);
759 			spin_unlock_irqrestore(&ec->lock, flags);
760 		} while (time_before(jiffies, delay));
761 		pr_debug("controller reset, restart transaction\n");
762 		spin_lock_irqsave(&ec->lock, flags);
763 		start_transaction(ec);
764 		spin_unlock_irqrestore(&ec->lock, flags);
765 	}
766 	return -ETIME;
767 }
768 
769 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
770 					struct transaction *t)
771 {
772 	unsigned long tmp;
773 	int ret = 0;
774 
775 	/* start transaction */
776 	spin_lock_irqsave(&ec->lock, tmp);
777 	/* Enable GPE for command processing (IBF=0/OBF=1) */
778 	if (!acpi_ec_submit_flushable_request(ec)) {
779 		ret = -EINVAL;
780 		goto unlock;
781 	}
782 	ec_dbg_ref(ec, "Increase command");
783 	/* following two actions should be kept atomic */
784 	ec->curr = t;
785 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
786 	start_transaction(ec);
787 	spin_unlock_irqrestore(&ec->lock, tmp);
788 
789 	ret = ec_poll(ec);
790 
791 	spin_lock_irqsave(&ec->lock, tmp);
792 	if (t->irq_count == ec_storm_threshold)
793 		acpi_ec_unmask_events(ec);
794 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
795 	ec->curr = NULL;
796 	/* Disable GPE for command processing (IBF=0/OBF=1) */
797 	acpi_ec_complete_request(ec);
798 	ec_dbg_ref(ec, "Decrease command");
799 unlock:
800 	spin_unlock_irqrestore(&ec->lock, tmp);
801 	return ret;
802 }
803 
804 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
805 {
806 	int status;
807 	u32 glk;
808 
809 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
810 		return -EINVAL;
811 	if (t->rdata)
812 		memset(t->rdata, 0, t->rlen);
813 
814 	mutex_lock(&ec->mutex);
815 	if (ec->global_lock) {
816 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
817 		if (ACPI_FAILURE(status)) {
818 			status = -ENODEV;
819 			goto unlock;
820 		}
821 	}
822 
823 	status = acpi_ec_transaction_unlocked(ec, t);
824 
825 	if (ec->global_lock)
826 		acpi_release_global_lock(glk);
827 unlock:
828 	mutex_unlock(&ec->mutex);
829 	return status;
830 }
831 
832 static int acpi_ec_burst_enable(struct acpi_ec *ec)
833 {
834 	u8 d;
835 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
836 				.wdata = NULL, .rdata = &d,
837 				.wlen = 0, .rlen = 1};
838 
839 	return acpi_ec_transaction(ec, &t);
840 }
841 
842 static int acpi_ec_burst_disable(struct acpi_ec *ec)
843 {
844 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
845 				.wdata = NULL, .rdata = NULL,
846 				.wlen = 0, .rlen = 0};
847 
848 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
849 				acpi_ec_transaction(ec, &t) : 0;
850 }
851 
852 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
853 {
854 	int result;
855 	u8 d;
856 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
857 				.wdata = &address, .rdata = &d,
858 				.wlen = 1, .rlen = 1};
859 
860 	result = acpi_ec_transaction(ec, &t);
861 	*data = d;
862 	return result;
863 }
864 
865 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
866 {
867 	u8 wdata[2] = { address, data };
868 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
869 				.wdata = wdata, .rdata = NULL,
870 				.wlen = 2, .rlen = 0};
871 
872 	return acpi_ec_transaction(ec, &t);
873 }
874 
875 int ec_read(u8 addr, u8 *val)
876 {
877 	int err;
878 	u8 temp_data;
879 
880 	if (!first_ec)
881 		return -ENODEV;
882 
883 	err = acpi_ec_read(first_ec, addr, &temp_data);
884 
885 	if (!err) {
886 		*val = temp_data;
887 		return 0;
888 	}
889 	return err;
890 }
891 EXPORT_SYMBOL(ec_read);
892 
893 int ec_write(u8 addr, u8 val)
894 {
895 	int err;
896 
897 	if (!first_ec)
898 		return -ENODEV;
899 
900 	err = acpi_ec_write(first_ec, addr, val);
901 
902 	return err;
903 }
904 EXPORT_SYMBOL(ec_write);
905 
906 int ec_transaction(u8 command,
907 		   const u8 *wdata, unsigned wdata_len,
908 		   u8 *rdata, unsigned rdata_len)
909 {
910 	struct transaction t = {.command = command,
911 				.wdata = wdata, .rdata = rdata,
912 				.wlen = wdata_len, .rlen = rdata_len};
913 
914 	if (!first_ec)
915 		return -ENODEV;
916 
917 	return acpi_ec_transaction(first_ec, &t);
918 }
919 EXPORT_SYMBOL(ec_transaction);
920 
921 /* Get the handle to the EC device */
922 acpi_handle ec_get_handle(void)
923 {
924 	if (!first_ec)
925 		return NULL;
926 	return first_ec->handle;
927 }
928 EXPORT_SYMBOL(ec_get_handle);
929 
930 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
931 {
932 	unsigned long flags;
933 
934 	spin_lock_irqsave(&ec->lock, flags);
935 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
936 		ec_dbg_drv("Starting EC");
937 		/* Enable GPE for event processing (SCI_EVT=1) */
938 		if (!resuming) {
939 			acpi_ec_submit_request(ec);
940 			ec_dbg_ref(ec, "Increase driver");
941 		}
942 		ec_log_drv("EC started");
943 	}
944 	spin_unlock_irqrestore(&ec->lock, flags);
945 }
946 
947 static bool acpi_ec_stopped(struct acpi_ec *ec)
948 {
949 	unsigned long flags;
950 	bool flushed;
951 
952 	spin_lock_irqsave(&ec->lock, flags);
953 	flushed = acpi_ec_flushed(ec);
954 	spin_unlock_irqrestore(&ec->lock, flags);
955 	return flushed;
956 }
957 
958 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
959 {
960 	unsigned long flags;
961 
962 	spin_lock_irqsave(&ec->lock, flags);
963 	if (acpi_ec_started(ec)) {
964 		ec_dbg_drv("Stopping EC");
965 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
966 		spin_unlock_irqrestore(&ec->lock, flags);
967 		wait_event(ec->wait, acpi_ec_stopped(ec));
968 		spin_lock_irqsave(&ec->lock, flags);
969 		/* Disable GPE for event processing (SCI_EVT=1) */
970 		if (!suspending) {
971 			acpi_ec_complete_request(ec);
972 			ec_dbg_ref(ec, "Decrease driver");
973 		} else if (!ec_freeze_events)
974 			__acpi_ec_disable_event(ec);
975 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
976 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
977 		ec_log_drv("EC stopped");
978 	}
979 	spin_unlock_irqrestore(&ec->lock, flags);
980 }
981 
982 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
983 {
984 	unsigned long flags;
985 
986 	spin_lock_irqsave(&ec->lock, flags);
987 	ec->busy_polling = true;
988 	ec->polling_guard = 0;
989 	ec_log_drv("interrupt blocked");
990 	spin_unlock_irqrestore(&ec->lock, flags);
991 }
992 
993 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
994 {
995 	unsigned long flags;
996 
997 	spin_lock_irqsave(&ec->lock, flags);
998 	ec->busy_polling = ec_busy_polling;
999 	ec->polling_guard = ec_polling_guard;
1000 	ec_log_drv("interrupt unblocked");
1001 	spin_unlock_irqrestore(&ec->lock, flags);
1002 }
1003 
1004 void acpi_ec_block_transactions(void)
1005 {
1006 	struct acpi_ec *ec = first_ec;
1007 
1008 	if (!ec)
1009 		return;
1010 
1011 	mutex_lock(&ec->mutex);
1012 	/* Prevent transactions from being carried out */
1013 	acpi_ec_stop(ec, true);
1014 	mutex_unlock(&ec->mutex);
1015 }
1016 
1017 void acpi_ec_unblock_transactions(void)
1018 {
1019 	/*
1020 	 * Allow transactions to happen again (this function is called from
1021 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1022 	 */
1023 	if (first_ec)
1024 		acpi_ec_start(first_ec, true);
1025 }
1026 
1027 /* --------------------------------------------------------------------------
1028                                 Event Management
1029    -------------------------------------------------------------------------- */
1030 static struct acpi_ec_query_handler *
1031 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1032 {
1033 	struct acpi_ec_query_handler *handler;
1034 
1035 	mutex_lock(&ec->mutex);
1036 	list_for_each_entry(handler, &ec->list, node) {
1037 		if (value == handler->query_bit) {
1038 			kref_get(&handler->kref);
1039 			mutex_unlock(&ec->mutex);
1040 			return handler;
1041 		}
1042 	}
1043 	mutex_unlock(&ec->mutex);
1044 	return NULL;
1045 }
1046 
1047 static void acpi_ec_query_handler_release(struct kref *kref)
1048 {
1049 	struct acpi_ec_query_handler *handler =
1050 		container_of(kref, struct acpi_ec_query_handler, kref);
1051 
1052 	kfree(handler);
1053 }
1054 
1055 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1056 {
1057 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1058 }
1059 
1060 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1061 			      acpi_handle handle, acpi_ec_query_func func,
1062 			      void *data)
1063 {
1064 	struct acpi_ec_query_handler *handler =
1065 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1066 
1067 	if (!handler)
1068 		return -ENOMEM;
1069 
1070 	handler->query_bit = query_bit;
1071 	handler->handle = handle;
1072 	handler->func = func;
1073 	handler->data = data;
1074 	mutex_lock(&ec->mutex);
1075 	kref_init(&handler->kref);
1076 	list_add(&handler->node, &ec->list);
1077 	mutex_unlock(&ec->mutex);
1078 	return 0;
1079 }
1080 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1081 
1082 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1083 					  bool remove_all, u8 query_bit)
1084 {
1085 	struct acpi_ec_query_handler *handler, *tmp;
1086 	LIST_HEAD(free_list);
1087 
1088 	mutex_lock(&ec->mutex);
1089 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1090 		if (remove_all || query_bit == handler->query_bit) {
1091 			list_del_init(&handler->node);
1092 			list_add(&handler->node, &free_list);
1093 		}
1094 	}
1095 	mutex_unlock(&ec->mutex);
1096 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1097 		acpi_ec_put_query_handler(handler);
1098 }
1099 
1100 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1101 {
1102 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1103 }
1104 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1105 
1106 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1107 {
1108 	struct acpi_ec_query *q;
1109 	struct transaction *t;
1110 
1111 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1112 	if (!q)
1113 		return NULL;
1114 	INIT_WORK(&q->work, acpi_ec_event_processor);
1115 	t = &q->transaction;
1116 	t->command = ACPI_EC_COMMAND_QUERY;
1117 	t->rdata = pval;
1118 	t->rlen = 1;
1119 	return q;
1120 }
1121 
1122 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1123 {
1124 	if (q) {
1125 		if (q->handler)
1126 			acpi_ec_put_query_handler(q->handler);
1127 		kfree(q);
1128 	}
1129 }
1130 
1131 static void acpi_ec_event_processor(struct work_struct *work)
1132 {
1133 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1134 	struct acpi_ec_query_handler *handler = q->handler;
1135 
1136 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1137 	if (handler->func)
1138 		handler->func(handler->data);
1139 	else if (handler->handle)
1140 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1141 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1142 	acpi_ec_delete_query(q);
1143 }
1144 
1145 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1146 {
1147 	u8 value = 0;
1148 	int result;
1149 	struct acpi_ec_query *q;
1150 
1151 	q = acpi_ec_create_query(&value);
1152 	if (!q)
1153 		return -ENOMEM;
1154 
1155 	/*
1156 	 * Query the EC to find out which _Qxx method we need to evaluate.
1157 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1158 	 * bit to be cleared (and thus clearing the interrupt source).
1159 	 */
1160 	result = acpi_ec_transaction(ec, &q->transaction);
1161 	if (!value)
1162 		result = -ENODATA;
1163 	if (result)
1164 		goto err_exit;
1165 
1166 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1167 	if (!q->handler) {
1168 		result = -ENODATA;
1169 		goto err_exit;
1170 	}
1171 
1172 	/*
1173 	 * It is reported that _Qxx are evaluated in a parallel way on
1174 	 * Windows:
1175 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1176 	 *
1177 	 * Put this log entry before schedule_work() in order to make
1178 	 * it appearing before any other log entries occurred during the
1179 	 * work queue execution.
1180 	 */
1181 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1182 	if (!queue_work(ec_query_wq, &q->work)) {
1183 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1184 		result = -EBUSY;
1185 	}
1186 
1187 err_exit:
1188 	if (result)
1189 		acpi_ec_delete_query(q);
1190 	if (data)
1191 		*data = value;
1192 	return result;
1193 }
1194 
1195 static void acpi_ec_check_event(struct acpi_ec *ec)
1196 {
1197 	unsigned long flags;
1198 
1199 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1200 		if (ec_guard(ec)) {
1201 			spin_lock_irqsave(&ec->lock, flags);
1202 			/*
1203 			 * Take care of the SCI_EVT unless no one else is
1204 			 * taking care of it.
1205 			 */
1206 			if (!ec->curr)
1207 				advance_transaction(ec, false);
1208 			spin_unlock_irqrestore(&ec->lock, flags);
1209 		}
1210 	}
1211 }
1212 
1213 static void acpi_ec_event_handler(struct work_struct *work)
1214 {
1215 	unsigned long flags;
1216 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1217 
1218 	ec_dbg_evt("Event started");
1219 
1220 	spin_lock_irqsave(&ec->lock, flags);
1221 	while (ec->nr_pending_queries) {
1222 		spin_unlock_irqrestore(&ec->lock, flags);
1223 		(void)acpi_ec_query(ec, NULL);
1224 		spin_lock_irqsave(&ec->lock, flags);
1225 		ec->nr_pending_queries--;
1226 		/*
1227 		 * Before exit, make sure that this work item can be
1228 		 * scheduled again. There might be QR_EC failures, leaving
1229 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1230 		 * item from being scheduled again.
1231 		 */
1232 		if (!ec->nr_pending_queries) {
1233 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1234 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1235 				acpi_ec_complete_query(ec);
1236 		}
1237 	}
1238 	spin_unlock_irqrestore(&ec->lock, flags);
1239 
1240 	ec_dbg_evt("Event stopped");
1241 
1242 	acpi_ec_check_event(ec);
1243 }
1244 
1245 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1246 {
1247 	unsigned long flags;
1248 
1249 	spin_lock_irqsave(&ec->lock, flags);
1250 	advance_transaction(ec, true);
1251 	spin_unlock_irqrestore(&ec->lock, flags);
1252 }
1253 
1254 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1255 			       u32 gpe_number, void *data)
1256 {
1257 	acpi_ec_handle_interrupt(data);
1258 	return ACPI_INTERRUPT_HANDLED;
1259 }
1260 
1261 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1262 {
1263 	acpi_ec_handle_interrupt(data);
1264 	return IRQ_HANDLED;
1265 }
1266 
1267 /* --------------------------------------------------------------------------
1268  *                           Address Space Management
1269  * -------------------------------------------------------------------------- */
1270 
1271 static acpi_status
1272 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1273 		      u32 bits, u64 *value64,
1274 		      void *handler_context, void *region_context)
1275 {
1276 	struct acpi_ec *ec = handler_context;
1277 	int result = 0, i, bytes = bits / 8;
1278 	u8 *value = (u8 *)value64;
1279 
1280 	if ((address > 0xFF) || !value || !handler_context)
1281 		return AE_BAD_PARAMETER;
1282 
1283 	if (function != ACPI_READ && function != ACPI_WRITE)
1284 		return AE_BAD_PARAMETER;
1285 
1286 	if (ec->busy_polling || bits > 8)
1287 		acpi_ec_burst_enable(ec);
1288 
1289 	for (i = 0; i < bytes; ++i, ++address, ++value)
1290 		result = (function == ACPI_READ) ?
1291 			acpi_ec_read(ec, address, value) :
1292 			acpi_ec_write(ec, address, *value);
1293 
1294 	if (ec->busy_polling || bits > 8)
1295 		acpi_ec_burst_disable(ec);
1296 
1297 	switch (result) {
1298 	case -EINVAL:
1299 		return AE_BAD_PARAMETER;
1300 	case -ENODEV:
1301 		return AE_NOT_FOUND;
1302 	case -ETIME:
1303 		return AE_TIME;
1304 	default:
1305 		return AE_OK;
1306 	}
1307 }
1308 
1309 /* --------------------------------------------------------------------------
1310  *                             Driver Interface
1311  * -------------------------------------------------------------------------- */
1312 
1313 static acpi_status
1314 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1315 
1316 static void acpi_ec_free(struct acpi_ec *ec)
1317 {
1318 	if (first_ec == ec)
1319 		first_ec = NULL;
1320 	if (boot_ec == ec)
1321 		boot_ec = NULL;
1322 	kfree(ec);
1323 }
1324 
1325 static struct acpi_ec *acpi_ec_alloc(void)
1326 {
1327 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1328 
1329 	if (!ec)
1330 		return NULL;
1331 	mutex_init(&ec->mutex);
1332 	init_waitqueue_head(&ec->wait);
1333 	INIT_LIST_HEAD(&ec->list);
1334 	spin_lock_init(&ec->lock);
1335 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1336 	ec->timestamp = jiffies;
1337 	ec->busy_polling = true;
1338 	ec->polling_guard = 0;
1339 	ec->gpe = -1;
1340 	ec->irq = -1;
1341 	return ec;
1342 }
1343 
1344 static acpi_status
1345 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1346 			       void *context, void **return_value)
1347 {
1348 	char node_name[5];
1349 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1350 	struct acpi_ec *ec = context;
1351 	int value = 0;
1352 	acpi_status status;
1353 
1354 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1355 
1356 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1357 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1358 	return AE_OK;
1359 }
1360 
1361 static acpi_status
1362 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1363 {
1364 	acpi_status status;
1365 	unsigned long long tmp = 0;
1366 	struct acpi_ec *ec = context;
1367 
1368 	/* clear addr values, ec_parse_io_ports depend on it */
1369 	ec->command_addr = ec->data_addr = 0;
1370 
1371 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1372 				     ec_parse_io_ports, ec);
1373 	if (ACPI_FAILURE(status))
1374 		return status;
1375 	if (ec->data_addr == 0 || ec->command_addr == 0)
1376 		return AE_OK;
1377 
1378 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1379 		/*
1380 		 * Always inherit the GPE number setting from the ECDT
1381 		 * EC.
1382 		 */
1383 		ec->gpe = boot_ec->gpe;
1384 	} else {
1385 		/* Get GPE bit assignment (EC events). */
1386 		/* TODO: Add support for _GPE returning a package */
1387 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1388 		if (ACPI_SUCCESS(status))
1389 			ec->gpe = tmp;
1390 
1391 		/*
1392 		 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1393 		 * platforms which use GpioInt instead of GPE.
1394 		 */
1395 	}
1396 	/* Use the global lock for all EC transactions? */
1397 	tmp = 0;
1398 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1399 	ec->global_lock = tmp;
1400 	ec->handle = handle;
1401 	return AE_CTRL_TERMINATE;
1402 }
1403 
1404 static bool install_gpe_event_handler(struct acpi_ec *ec)
1405 {
1406 	acpi_status status;
1407 
1408 	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1409 					      ACPI_GPE_EDGE_TRIGGERED,
1410 					      &acpi_ec_gpe_handler, ec);
1411 	if (ACPI_FAILURE(status))
1412 		return false;
1413 
1414 	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1415 		acpi_ec_enable_gpe(ec, true);
1416 
1417 	return true;
1418 }
1419 
1420 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1421 {
1422 	return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1423 			   "ACPI EC", ec) >= 0;
1424 }
1425 
1426 /**
1427  * ec_install_handlers - Install service callbacks and register query methods.
1428  * @ec: Target EC.
1429  * @device: ACPI device object corresponding to @ec.
1430  *
1431  * Install a handler for the EC address space type unless it has been installed
1432  * already.  If @device is not NULL, also look for EC query methods in the
1433  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1434  * handler for the EC, if possible.
1435  *
1436  * Return:
1437  * -ENODEV if the address space handler cannot be installed, which means
1438  *  "unable to handle transactions",
1439  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1440  * or 0 (success) otherwise.
1441  */
1442 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1443 {
1444 	acpi_status status;
1445 
1446 	acpi_ec_start(ec, false);
1447 
1448 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1449 		acpi_ec_enter_noirq(ec);
1450 		status = acpi_install_address_space_handler(ec->handle,
1451 							    ACPI_ADR_SPACE_EC,
1452 							    &acpi_ec_space_handler,
1453 							    NULL, ec);
1454 		if (ACPI_FAILURE(status)) {
1455 			acpi_ec_stop(ec, false);
1456 			return -ENODEV;
1457 		}
1458 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1459 	}
1460 
1461 	if (!device)
1462 		return 0;
1463 
1464 	if (ec->gpe < 0) {
1465 		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1466 		int irq = acpi_dev_gpio_irq_get(device, 0);
1467 		/*
1468 		 * Bail out right away for deferred probing or complete the
1469 		 * initialization regardless of any other errors.
1470 		 */
1471 		if (irq == -EPROBE_DEFER)
1472 			return -EPROBE_DEFER;
1473 		else if (irq >= 0)
1474 			ec->irq = irq;
1475 	}
1476 
1477 	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1478 		/* Find and register all query methods */
1479 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1480 				    acpi_ec_register_query_methods,
1481 				    NULL, ec, NULL);
1482 		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1483 	}
1484 	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1485 		bool ready = false;
1486 
1487 		if (ec->gpe >= 0)
1488 			ready = install_gpe_event_handler(ec);
1489 		else if (ec->irq >= 0)
1490 			ready = install_gpio_irq_event_handler(ec);
1491 
1492 		if (ready) {
1493 			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1494 			acpi_ec_leave_noirq(ec);
1495 		}
1496 		/*
1497 		 * Failures to install an event handler are not fatal, because
1498 		 * the EC can be polled for events.
1499 		 */
1500 	}
1501 	/* EC is fully operational, allow queries */
1502 	acpi_ec_enable_event(ec);
1503 
1504 	return 0;
1505 }
1506 
1507 static void ec_remove_handlers(struct acpi_ec *ec)
1508 {
1509 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1510 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1511 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1512 			pr_err("failed to remove space handler\n");
1513 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1514 	}
1515 
1516 	/*
1517 	 * Stops handling the EC transactions after removing the operation
1518 	 * region handler. This is required because _REG(DISCONNECT)
1519 	 * invoked during the removal can result in new EC transactions.
1520 	 *
1521 	 * Flushes the EC requests and thus disables the GPE before
1522 	 * removing the GPE handler. This is required by the current ACPICA
1523 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1524 	 * it is indicated but there is no way to handle it. So the drivers
1525 	 * must disable the GPEs prior to removing the GPE handlers.
1526 	 */
1527 	acpi_ec_stop(ec, false);
1528 
1529 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1530 		if (ec->gpe >= 0 &&
1531 		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1532 				 &acpi_ec_gpe_handler)))
1533 			pr_err("failed to remove gpe handler\n");
1534 
1535 		if (ec->irq >= 0)
1536 			free_irq(ec->irq, ec);
1537 
1538 		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1539 	}
1540 	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1541 		acpi_ec_remove_query_handlers(ec, true, 0);
1542 		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1543 	}
1544 }
1545 
1546 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1547 {
1548 	int ret;
1549 
1550 	ret = ec_install_handlers(ec, device);
1551 	if (ret)
1552 		return ret;
1553 
1554 	/* First EC capable of handling transactions */
1555 	if (!first_ec)
1556 		first_ec = ec;
1557 
1558 	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1559 		ec->data_addr);
1560 
1561 	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1562 		if (ec->gpe >= 0)
1563 			pr_info("GPE=0x%x\n", ec->gpe);
1564 		else
1565 			pr_info("IRQ=%d\n", ec->irq);
1566 	}
1567 
1568 	return ret;
1569 }
1570 
1571 static int acpi_ec_add(struct acpi_device *device)
1572 {
1573 	struct acpi_ec *ec;
1574 	int ret;
1575 
1576 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1577 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1578 
1579 	if (boot_ec && (boot_ec->handle == device->handle ||
1580 	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1581 		/* Fast path: this device corresponds to the boot EC. */
1582 		ec = boot_ec;
1583 	} else {
1584 		acpi_status status;
1585 
1586 		ec = acpi_ec_alloc();
1587 		if (!ec)
1588 			return -ENOMEM;
1589 
1590 		status = ec_parse_device(device->handle, 0, ec, NULL);
1591 		if (status != AE_CTRL_TERMINATE) {
1592 			ret = -EINVAL;
1593 			goto err;
1594 		}
1595 
1596 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1597 		    ec->data_addr == boot_ec->data_addr &&
1598 		    !EC_FLAGS_TRUST_DSDT_GPE) {
1599 			/*
1600 			 * Trust PNP0C09 namespace location rather than
1601 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1602 			 * because of ASUS quirks, so do not change
1603 			 * boot_ec->gpe to ec->gpe.
1604 			 */
1605 			boot_ec->handle = ec->handle;
1606 			acpi_handle_debug(ec->handle, "duplicated.\n");
1607 			acpi_ec_free(ec);
1608 			ec = boot_ec;
1609 		}
1610 	}
1611 
1612 	ret = acpi_ec_setup(ec, device);
1613 	if (ret)
1614 		goto err;
1615 
1616 	if (ec == boot_ec)
1617 		acpi_handle_info(boot_ec->handle,
1618 				 "Boot %s EC initialization complete\n",
1619 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1620 
1621 	acpi_handle_info(ec->handle,
1622 			 "EC: Used to handle transactions and events\n");
1623 
1624 	device->driver_data = ec;
1625 
1626 	ret = !!request_region(ec->data_addr, 1, "EC data");
1627 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1628 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1629 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1630 
1631 	/* Reprobe devices depending on the EC */
1632 	acpi_dev_clear_dependencies(device);
1633 
1634 	acpi_handle_debug(ec->handle, "enumerated.\n");
1635 	return 0;
1636 
1637 err:
1638 	if (ec != boot_ec)
1639 		acpi_ec_free(ec);
1640 
1641 	return ret;
1642 }
1643 
1644 static int acpi_ec_remove(struct acpi_device *device)
1645 {
1646 	struct acpi_ec *ec;
1647 
1648 	if (!device)
1649 		return -EINVAL;
1650 
1651 	ec = acpi_driver_data(device);
1652 	release_region(ec->data_addr, 1);
1653 	release_region(ec->command_addr, 1);
1654 	device->driver_data = NULL;
1655 	if (ec != boot_ec) {
1656 		ec_remove_handlers(ec);
1657 		acpi_ec_free(ec);
1658 	}
1659 	return 0;
1660 }
1661 
1662 static acpi_status
1663 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1664 {
1665 	struct acpi_ec *ec = context;
1666 
1667 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1668 		return AE_OK;
1669 
1670 	/*
1671 	 * The first address region returned is the data port, and
1672 	 * the second address region returned is the status/command
1673 	 * port.
1674 	 */
1675 	if (ec->data_addr == 0)
1676 		ec->data_addr = resource->data.io.minimum;
1677 	else if (ec->command_addr == 0)
1678 		ec->command_addr = resource->data.io.minimum;
1679 	else
1680 		return AE_CTRL_TERMINATE;
1681 
1682 	return AE_OK;
1683 }
1684 
1685 static const struct acpi_device_id ec_device_ids[] = {
1686 	{"PNP0C09", 0},
1687 	{ACPI_ECDT_HID, 0},
1688 	{"", 0},
1689 };
1690 
1691 /*
1692  * This function is not Windows-compatible as Windows never enumerates the
1693  * namespace EC before the main ACPI device enumeration process. It is
1694  * retained for historical reason and will be deprecated in the future.
1695  */
1696 void __init acpi_ec_dsdt_probe(void)
1697 {
1698 	struct acpi_ec *ec;
1699 	acpi_status status;
1700 	int ret;
1701 
1702 	/*
1703 	 * If a platform has ECDT, there is no need to proceed as the
1704 	 * following probe is not a part of the ACPI device enumeration,
1705 	 * executing _STA is not safe, and thus this probe may risk of
1706 	 * picking up an invalid EC device.
1707 	 */
1708 	if (boot_ec)
1709 		return;
1710 
1711 	ec = acpi_ec_alloc();
1712 	if (!ec)
1713 		return;
1714 
1715 	/*
1716 	 * At this point, the namespace is initialized, so start to find
1717 	 * the namespace objects.
1718 	 */
1719 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1720 	if (ACPI_FAILURE(status) || !ec->handle) {
1721 		acpi_ec_free(ec);
1722 		return;
1723 	}
1724 
1725 	/*
1726 	 * When the DSDT EC is available, always re-configure boot EC to
1727 	 * have _REG evaluated. _REG can only be evaluated after the
1728 	 * namespace initialization.
1729 	 * At this point, the GPE is not fully initialized, so do not to
1730 	 * handle the events.
1731 	 */
1732 	ret = acpi_ec_setup(ec, NULL);
1733 	if (ret) {
1734 		acpi_ec_free(ec);
1735 		return;
1736 	}
1737 
1738 	boot_ec = ec;
1739 
1740 	acpi_handle_info(ec->handle,
1741 			 "Boot DSDT EC used to handle transactions\n");
1742 }
1743 
1744 /*
1745  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1746  *
1747  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1748  * found a matching object in the namespace.
1749  *
1750  * Next, in case the DSDT EC is not functioning, it is still necessary to
1751  * provide a functional ECDT EC to handle events, so add an extra device object
1752  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1753  *
1754  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1755  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1756  */
1757 static void __init acpi_ec_ecdt_start(void)
1758 {
1759 	struct acpi_table_ecdt *ecdt_ptr;
1760 	acpi_handle handle;
1761 	acpi_status status;
1762 
1763 	/* Bail out if a matching EC has been found in the namespace. */
1764 	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1765 		return;
1766 
1767 	/* Look up the object pointed to from the ECDT in the namespace. */
1768 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1769 				(struct acpi_table_header **)&ecdt_ptr);
1770 	if (ACPI_FAILURE(status))
1771 		return;
1772 
1773 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1774 	if (ACPI_SUCCESS(status)) {
1775 		boot_ec->handle = handle;
1776 
1777 		/* Add a special ACPI device object to represent the boot EC. */
1778 		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1779 	}
1780 
1781 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1782 }
1783 
1784 /*
1785  * On some hardware it is necessary to clear events accumulated by the EC during
1786  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1787  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1788  *
1789  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1790  *
1791  * Ideally, the EC should also be instructed NOT to accumulate events during
1792  * sleep (which Windows seems to do somehow), but the interface to control this
1793  * behaviour is not known at this time.
1794  *
1795  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1796  * however it is very likely that other Samsung models are affected.
1797  *
1798  * On systems which don't accumulate _Q events during sleep, this extra check
1799  * should be harmless.
1800  */
1801 static int ec_clear_on_resume(const struct dmi_system_id *id)
1802 {
1803 	pr_debug("Detected system needing EC poll on resume.\n");
1804 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1805 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1806 	return 0;
1807 }
1808 
1809 /*
1810  * Some ECDTs contain wrong register addresses.
1811  * MSI MS-171F
1812  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1813  */
1814 static int ec_correct_ecdt(const struct dmi_system_id *id)
1815 {
1816 	pr_debug("Detected system needing ECDT address correction.\n");
1817 	EC_FLAGS_CORRECT_ECDT = 1;
1818 	return 0;
1819 }
1820 
1821 /*
1822  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1823  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1824  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1825  */
1826 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1827 {
1828 	pr_debug("Detected system needing DSDT GPE setting.\n");
1829 	EC_FLAGS_TRUST_DSDT_GPE = 1;
1830 	return 0;
1831 }
1832 
1833 /*
1834  * Some DSDTs contain wrong GPE setting.
1835  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1836  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1837  */
1838 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1839 {
1840 	pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1841 	EC_FLAGS_IGNORE_DSDT_GPE = 1;
1842 	return 0;
1843 }
1844 
1845 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1846 	{
1847 	ec_correct_ecdt, "MSI MS-171F", {
1848 	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1849 	DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1850 	{
1851 	ec_honor_ecdt_gpe, "ASUS FX502VD", {
1852 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1853 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1854 	{
1855 	ec_honor_ecdt_gpe, "ASUS FX502VE", {
1856 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1857 	DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1858 	{
1859 	ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1860 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1861 	DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1862 	{
1863 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BA", {
1864 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1865 	DMI_MATCH(DMI_PRODUCT_NAME, "X505BA"),}, NULL},
1866 	{
1867 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X505BP", {
1868 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1869 	DMI_MATCH(DMI_PRODUCT_NAME, "X505BP"),}, NULL},
1870 	{
1871 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BA", {
1872 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1873 	DMI_MATCH(DMI_PRODUCT_NAME, "X542BA"),}, NULL},
1874 	{
1875 	ec_honor_ecdt_gpe, "ASUSTeK COMPUTER INC. X542BP", {
1876 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1877 	DMI_MATCH(DMI_PRODUCT_NAME, "X542BP"),}, NULL},
1878 	{
1879 	ec_honor_ecdt_gpe, "ASUS X550VXK", {
1880 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1881 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1882 	{
1883 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1884 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1885 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1886 	{
1887 	/* https://bugzilla.kernel.org/show_bug.cgi?id=209989 */
1888 	ec_honor_dsdt_gpe, "HP Pavilion Gaming Laptop 15-cx0xxx", {
1889 	DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1890 	DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),}, NULL},
1891 	{
1892 	ec_clear_on_resume, "Samsung hardware", {
1893 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1894 	{},
1895 };
1896 
1897 void __init acpi_ec_ecdt_probe(void)
1898 {
1899 	struct acpi_table_ecdt *ecdt_ptr;
1900 	struct acpi_ec *ec;
1901 	acpi_status status;
1902 	int ret;
1903 
1904 	/* Generate a boot ec context. */
1905 	dmi_check_system(ec_dmi_table);
1906 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1907 				(struct acpi_table_header **)&ecdt_ptr);
1908 	if (ACPI_FAILURE(status))
1909 		return;
1910 
1911 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1912 		/*
1913 		 * Asus X50GL:
1914 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1915 		 */
1916 		goto out;
1917 	}
1918 
1919 	ec = acpi_ec_alloc();
1920 	if (!ec)
1921 		goto out;
1922 
1923 	if (EC_FLAGS_CORRECT_ECDT) {
1924 		ec->command_addr = ecdt_ptr->data.address;
1925 		ec->data_addr = ecdt_ptr->control.address;
1926 	} else {
1927 		ec->command_addr = ecdt_ptr->control.address;
1928 		ec->data_addr = ecdt_ptr->data.address;
1929 	}
1930 
1931 	/*
1932 	 * Ignore the GPE value on Reduced Hardware platforms.
1933 	 * Some products have this set to an erroneous value.
1934 	 */
1935 	if (!acpi_gbl_reduced_hardware)
1936 		ec->gpe = ecdt_ptr->gpe;
1937 
1938 	ec->handle = ACPI_ROOT_OBJECT;
1939 
1940 	/*
1941 	 * At this point, the namespace is not initialized, so do not find
1942 	 * the namespace objects, or handle the events.
1943 	 */
1944 	ret = acpi_ec_setup(ec, NULL);
1945 	if (ret) {
1946 		acpi_ec_free(ec);
1947 		goto out;
1948 	}
1949 
1950 	boot_ec = ec;
1951 	boot_ec_is_ecdt = true;
1952 
1953 	pr_info("Boot ECDT EC used to handle transactions\n");
1954 
1955 out:
1956 	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1957 }
1958 
1959 #ifdef CONFIG_PM_SLEEP
1960 static int acpi_ec_suspend(struct device *dev)
1961 {
1962 	struct acpi_ec *ec =
1963 		acpi_driver_data(to_acpi_device(dev));
1964 
1965 	if (!pm_suspend_no_platform() && ec_freeze_events)
1966 		acpi_ec_disable_event(ec);
1967 	return 0;
1968 }
1969 
1970 static int acpi_ec_suspend_noirq(struct device *dev)
1971 {
1972 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1973 
1974 	/*
1975 	 * The SCI handler doesn't run at this point, so the GPE can be
1976 	 * masked at the low level without side effects.
1977 	 */
1978 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1979 	    ec->gpe >= 0 && ec->reference_count >= 1)
1980 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1981 
1982 	acpi_ec_enter_noirq(ec);
1983 
1984 	return 0;
1985 }
1986 
1987 static int acpi_ec_resume_noirq(struct device *dev)
1988 {
1989 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1990 
1991 	acpi_ec_leave_noirq(ec);
1992 
1993 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1994 	    ec->gpe >= 0 && ec->reference_count >= 1)
1995 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1996 
1997 	return 0;
1998 }
1999 
2000 static int acpi_ec_resume(struct device *dev)
2001 {
2002 	struct acpi_ec *ec =
2003 		acpi_driver_data(to_acpi_device(dev));
2004 
2005 	acpi_ec_enable_event(ec);
2006 	return 0;
2007 }
2008 
2009 void acpi_ec_mark_gpe_for_wake(void)
2010 {
2011 	if (first_ec && !ec_no_wakeup)
2012 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2013 }
2014 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2015 
2016 void acpi_ec_set_gpe_wake_mask(u8 action)
2017 {
2018 	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2019 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2020 }
2021 
2022 bool acpi_ec_dispatch_gpe(void)
2023 {
2024 	u32 ret;
2025 
2026 	if (!first_ec)
2027 		return acpi_any_gpe_status_set(U32_MAX);
2028 
2029 	/*
2030 	 * Report wakeup if the status bit is set for any enabled GPE other
2031 	 * than the EC one.
2032 	 */
2033 	if (acpi_any_gpe_status_set(first_ec->gpe))
2034 		return true;
2035 
2036 	/*
2037 	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2038 	 * to allow the caller to process events properly after that.
2039 	 */
2040 	ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2041 	if (ret == ACPI_INTERRUPT_HANDLED)
2042 		pm_pr_dbg("ACPI EC GPE dispatched\n");
2043 
2044 	/* Flush the event and query workqueues. */
2045 	acpi_ec_flush_work();
2046 
2047 	return false;
2048 }
2049 #endif /* CONFIG_PM_SLEEP */
2050 
2051 static const struct dev_pm_ops acpi_ec_pm = {
2052 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2053 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2054 };
2055 
2056 static int param_set_event_clearing(const char *val,
2057 				    const struct kernel_param *kp)
2058 {
2059 	int result = 0;
2060 
2061 	if (!strncmp(val, "status", sizeof("status") - 1)) {
2062 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2063 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2064 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2065 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2066 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2067 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2068 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2069 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2070 	} else
2071 		result = -EINVAL;
2072 	return result;
2073 }
2074 
2075 static int param_get_event_clearing(char *buffer,
2076 				    const struct kernel_param *kp)
2077 {
2078 	switch (ec_event_clearing) {
2079 	case ACPI_EC_EVT_TIMING_STATUS:
2080 		return sprintf(buffer, "status\n");
2081 	case ACPI_EC_EVT_TIMING_QUERY:
2082 		return sprintf(buffer, "query\n");
2083 	case ACPI_EC_EVT_TIMING_EVENT:
2084 		return sprintf(buffer, "event\n");
2085 	default:
2086 		return sprintf(buffer, "invalid\n");
2087 	}
2088 	return 0;
2089 }
2090 
2091 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2092 		  NULL, 0644);
2093 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2094 
2095 static struct acpi_driver acpi_ec_driver = {
2096 	.name = "ec",
2097 	.class = ACPI_EC_CLASS,
2098 	.ids = ec_device_ids,
2099 	.ops = {
2100 		.add = acpi_ec_add,
2101 		.remove = acpi_ec_remove,
2102 		},
2103 	.drv.pm = &acpi_ec_pm,
2104 };
2105 
2106 static void acpi_ec_destroy_workqueues(void)
2107 {
2108 	if (ec_wq) {
2109 		destroy_workqueue(ec_wq);
2110 		ec_wq = NULL;
2111 	}
2112 	if (ec_query_wq) {
2113 		destroy_workqueue(ec_query_wq);
2114 		ec_query_wq = NULL;
2115 	}
2116 }
2117 
2118 static int acpi_ec_init_workqueues(void)
2119 {
2120 	if (!ec_wq)
2121 		ec_wq = alloc_ordered_workqueue("kec", 0);
2122 
2123 	if (!ec_query_wq)
2124 		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2125 
2126 	if (!ec_wq || !ec_query_wq) {
2127 		acpi_ec_destroy_workqueues();
2128 		return -ENODEV;
2129 	}
2130 	return 0;
2131 }
2132 
2133 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2134 	{
2135 		.ident = "Thinkpad X1 Carbon 6th",
2136 		.matches = {
2137 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2138 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2139 		},
2140 	},
2141 	{
2142 		.ident = "ThinkPad X1 Carbon 6th",
2143 		.matches = {
2144 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2145 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2146 		},
2147 	},
2148 	{
2149 		.ident = "ThinkPad X1 Yoga 3rd",
2150 		.matches = {
2151 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2152 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2153 		},
2154 	},
2155 	{
2156 		.ident = "HP ZHAN 66 Pro",
2157 		.matches = {
2158 			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2159 			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2160 		},
2161 	},
2162 	{ },
2163 };
2164 
2165 void __init acpi_ec_init(void)
2166 {
2167 	int result;
2168 
2169 	result = acpi_ec_init_workqueues();
2170 	if (result)
2171 		return;
2172 
2173 	/*
2174 	 * Disable EC wakeup on following systems to prevent periodic
2175 	 * wakeup from EC GPE.
2176 	 */
2177 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2178 		ec_no_wakeup = true;
2179 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2180 	}
2181 
2182 	/* Driver must be registered after acpi_ec_init_workqueues(). */
2183 	acpi_bus_register_driver(&acpi_ec_driver);
2184 
2185 	acpi_ec_ecdt_start();
2186 }
2187 
2188 /* EC driver currently not unloadable */
2189 #if 0
2190 static void __exit acpi_ec_exit(void)
2191 {
2192 
2193 	acpi_bus_unregister_driver(&acpi_ec_driver);
2194 	acpi_ec_destroy_workqueues();
2195 }
2196 #endif	/* 0 */
2197