xref: /linux/drivers/acpi/ec.c (revision 63307d015b91e626c97bb82e88054af3d0b74643)
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/acpi.h>
29 #include <linux/dmi.h>
30 #include <asm/io.h>
31 
32 #include "internal.h"
33 
34 #define ACPI_EC_CLASS			"embedded_controller"
35 #define ACPI_EC_DEVICE_NAME		"Embedded Controller"
36 #define ACPI_EC_FILE_INFO		"info"
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_GPE_HANDLER_INSTALLED,	/* GPE handler installed */
98 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
99 	EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
100 	EC_FLAGS_STARTED,		/* Driver is started */
101 	EC_FLAGS_STOPPED,		/* Driver is stopped */
102 	EC_FLAGS_GPE_MASKED,		/* GPE masked */
103 };
104 
105 #define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
106 #define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
107 
108 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
109 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
110 module_param(ec_delay, uint, 0644);
111 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
112 
113 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
114 module_param(ec_max_queries, uint, 0644);
115 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
116 
117 static bool ec_busy_polling __read_mostly;
118 module_param(ec_busy_polling, bool, 0644);
119 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
120 
121 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
122 module_param(ec_polling_guard, uint, 0644);
123 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
124 
125 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
126 
127 /*
128  * If the number of false interrupts per one transaction exceeds
129  * this threshold, will think there is a GPE storm happened and
130  * will disable the GPE for normal transaction.
131  */
132 static unsigned int ec_storm_threshold  __read_mostly = 8;
133 module_param(ec_storm_threshold, uint, 0644);
134 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
135 
136 static bool ec_freeze_events __read_mostly = false;
137 module_param(ec_freeze_events, bool, 0644);
138 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
139 
140 static bool ec_no_wakeup __read_mostly;
141 module_param(ec_no_wakeup, bool, 0644);
142 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
143 
144 struct acpi_ec_query_handler {
145 	struct list_head node;
146 	acpi_ec_query_func func;
147 	acpi_handle handle;
148 	void *data;
149 	u8 query_bit;
150 	struct kref kref;
151 };
152 
153 struct transaction {
154 	const u8 *wdata;
155 	u8 *rdata;
156 	unsigned short irq_count;
157 	u8 command;
158 	u8 wi;
159 	u8 ri;
160 	u8 wlen;
161 	u8 rlen;
162 	u8 flags;
163 };
164 
165 struct acpi_ec_query {
166 	struct transaction transaction;
167 	struct work_struct work;
168 	struct acpi_ec_query_handler *handler;
169 };
170 
171 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
172 static void advance_transaction(struct acpi_ec *ec);
173 static void acpi_ec_event_handler(struct work_struct *work);
174 static void acpi_ec_event_processor(struct work_struct *work);
175 
176 struct acpi_ec *first_ec;
177 EXPORT_SYMBOL(first_ec);
178 
179 static struct acpi_ec *boot_ec;
180 static bool boot_ec_is_ecdt = false;
181 static struct workqueue_struct *ec_query_wq;
182 
183 static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
184 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
185 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
186 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
187 
188 /* --------------------------------------------------------------------------
189  *                           Logging/Debugging
190  * -------------------------------------------------------------------------- */
191 
192 /*
193  * Splitters used by the developers to track the boundary of the EC
194  * handling processes.
195  */
196 #ifdef DEBUG
197 #define EC_DBG_SEP	" "
198 #define EC_DBG_DRV	"+++++"
199 #define EC_DBG_STM	"====="
200 #define EC_DBG_REQ	"*****"
201 #define EC_DBG_EVT	"#####"
202 #else
203 #define EC_DBG_SEP	""
204 #define EC_DBG_DRV
205 #define EC_DBG_STM
206 #define EC_DBG_REQ
207 #define EC_DBG_EVT
208 #endif
209 
210 #define ec_log_raw(fmt, ...) \
211 	pr_info(fmt "\n", ##__VA_ARGS__)
212 #define ec_dbg_raw(fmt, ...) \
213 	pr_debug(fmt "\n", ##__VA_ARGS__)
214 #define ec_log(filter, fmt, ...) \
215 	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
216 #define ec_dbg(filter, fmt, ...) \
217 	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
218 
219 #define ec_log_drv(fmt, ...) \
220 	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
221 #define ec_dbg_drv(fmt, ...) \
222 	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
223 #define ec_dbg_stm(fmt, ...) \
224 	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
225 #define ec_dbg_req(fmt, ...) \
226 	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
227 #define ec_dbg_evt(fmt, ...) \
228 	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
229 #define ec_dbg_ref(ec, fmt, ...) \
230 	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
231 
232 /* --------------------------------------------------------------------------
233  *                           Device Flags
234  * -------------------------------------------------------------------------- */
235 
236 static bool acpi_ec_started(struct acpi_ec *ec)
237 {
238 	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
239 	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
240 }
241 
242 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
243 {
244 	/*
245 	 * There is an OSPM early stage logic. During the early stages
246 	 * (boot/resume), OSPMs shouldn't enable the event handling, only
247 	 * the EC transactions are allowed to be performed.
248 	 */
249 	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
250 		return false;
251 	/*
252 	 * However, disabling the event handling is experimental for late
253 	 * stage (suspend), and is controlled by the boot parameter of
254 	 * "ec_freeze_events":
255 	 * 1. true:  The EC event handling is disabled before entering
256 	 *           the noirq stage.
257 	 * 2. false: The EC event handling is automatically disabled as
258 	 *           soon as the EC driver is stopped.
259 	 */
260 	if (ec_freeze_events)
261 		return acpi_ec_started(ec);
262 	else
263 		return test_bit(EC_FLAGS_STARTED, &ec->flags);
264 }
265 
266 static bool acpi_ec_flushed(struct acpi_ec *ec)
267 {
268 	return ec->reference_count == 1;
269 }
270 
271 /* --------------------------------------------------------------------------
272  *                           EC Registers
273  * -------------------------------------------------------------------------- */
274 
275 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
276 {
277 	u8 x = inb(ec->command_addr);
278 
279 	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
280 		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
281 		   x,
282 		   !!(x & ACPI_EC_FLAG_SCI),
283 		   !!(x & ACPI_EC_FLAG_BURST),
284 		   !!(x & ACPI_EC_FLAG_CMD),
285 		   !!(x & ACPI_EC_FLAG_IBF),
286 		   !!(x & ACPI_EC_FLAG_OBF));
287 	return x;
288 }
289 
290 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
291 {
292 	u8 x = inb(ec->data_addr);
293 
294 	ec->timestamp = jiffies;
295 	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
296 	return x;
297 }
298 
299 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
300 {
301 	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
302 	outb(command, ec->command_addr);
303 	ec->timestamp = jiffies;
304 }
305 
306 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
307 {
308 	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
309 	outb(data, ec->data_addr);
310 	ec->timestamp = jiffies;
311 }
312 
313 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
314 static const char *acpi_ec_cmd_string(u8 cmd)
315 {
316 	switch (cmd) {
317 	case 0x80:
318 		return "RD_EC";
319 	case 0x81:
320 		return "WR_EC";
321 	case 0x82:
322 		return "BE_EC";
323 	case 0x83:
324 		return "BD_EC";
325 	case 0x84:
326 		return "QR_EC";
327 	}
328 	return "UNKNOWN";
329 }
330 #else
331 #define acpi_ec_cmd_string(cmd)		"UNDEF"
332 #endif
333 
334 /* --------------------------------------------------------------------------
335  *                           GPE Registers
336  * -------------------------------------------------------------------------- */
337 
338 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
339 {
340 	acpi_event_status gpe_status = 0;
341 
342 	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
343 	return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
344 }
345 
346 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
347 {
348 	if (open)
349 		acpi_enable_gpe(NULL, ec->gpe);
350 	else {
351 		BUG_ON(ec->reference_count < 1);
352 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
353 	}
354 	if (acpi_ec_is_gpe_raised(ec)) {
355 		/*
356 		 * On some platforms, EN=1 writes cannot trigger GPE. So
357 		 * software need to manually trigger a pseudo GPE event on
358 		 * EN=1 writes.
359 		 */
360 		ec_dbg_raw("Polling quirk");
361 		advance_transaction(ec);
362 	}
363 }
364 
365 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
366 {
367 	if (close)
368 		acpi_disable_gpe(NULL, ec->gpe);
369 	else {
370 		BUG_ON(ec->reference_count < 1);
371 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
372 	}
373 }
374 
375 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
376 {
377 	/*
378 	 * GPE STS is a W1C register, which means:
379 	 * 1. Software can clear it without worrying about clearing other
380 	 *    GPEs' STS bits when the hardware sets them in parallel.
381 	 * 2. As long as software can ensure only clearing it when it is
382 	 *    set, hardware won't set it in parallel.
383 	 * So software can clear GPE in any contexts.
384 	 * Warning: do not move the check into advance_transaction() as the
385 	 * EC commands will be sent without GPE raised.
386 	 */
387 	if (!acpi_ec_is_gpe_raised(ec))
388 		return;
389 	acpi_clear_gpe(NULL, ec->gpe);
390 }
391 
392 /* --------------------------------------------------------------------------
393  *                           Transaction Management
394  * -------------------------------------------------------------------------- */
395 
396 static void acpi_ec_submit_request(struct acpi_ec *ec)
397 {
398 	ec->reference_count++;
399 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
400 	    ec->reference_count == 1)
401 		acpi_ec_enable_gpe(ec, true);
402 }
403 
404 static void acpi_ec_complete_request(struct acpi_ec *ec)
405 {
406 	bool flushed = false;
407 
408 	ec->reference_count--;
409 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags) &&
410 	    ec->reference_count == 0)
411 		acpi_ec_disable_gpe(ec, true);
412 	flushed = acpi_ec_flushed(ec);
413 	if (flushed)
414 		wake_up(&ec->wait);
415 }
416 
417 static void acpi_ec_mask_gpe(struct acpi_ec *ec)
418 {
419 	if (!test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
420 		acpi_ec_disable_gpe(ec, false);
421 		ec_dbg_drv("Polling enabled");
422 		set_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
423 	}
424 }
425 
426 static void acpi_ec_unmask_gpe(struct acpi_ec *ec)
427 {
428 	if (test_bit(EC_FLAGS_GPE_MASKED, &ec->flags)) {
429 		clear_bit(EC_FLAGS_GPE_MASKED, &ec->flags);
430 		acpi_ec_enable_gpe(ec, false);
431 		ec_dbg_drv("Polling disabled");
432 	}
433 }
434 
435 /*
436  * acpi_ec_submit_flushable_request() - Increase the reference count unless
437  *                                      the flush operation is not in
438  *                                      progress
439  * @ec: the EC device
440  *
441  * This function must be used before taking a new action that should hold
442  * the reference count.  If this function returns false, then the action
443  * must be discarded or it will prevent the flush operation from being
444  * completed.
445  */
446 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
447 {
448 	if (!acpi_ec_started(ec))
449 		return false;
450 	acpi_ec_submit_request(ec);
451 	return true;
452 }
453 
454 static void acpi_ec_submit_query(struct acpi_ec *ec)
455 {
456 	acpi_ec_mask_gpe(ec);
457 	if (!acpi_ec_event_enabled(ec))
458 		return;
459 	if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
460 		ec_dbg_evt("Command(%s) submitted/blocked",
461 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
462 		ec->nr_pending_queries++;
463 		schedule_work(&ec->work);
464 	}
465 }
466 
467 static void acpi_ec_complete_query(struct acpi_ec *ec)
468 {
469 	if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
470 		ec_dbg_evt("Command(%s) unblocked",
471 			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
472 	acpi_ec_unmask_gpe(ec);
473 }
474 
475 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
476 {
477 	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
478 		ec_log_drv("event unblocked");
479 	/*
480 	 * Unconditionally invoke this once after enabling the event
481 	 * handling mechanism to detect the pending events.
482 	 */
483 	advance_transaction(ec);
484 }
485 
486 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
487 {
488 	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
489 		ec_log_drv("event blocked");
490 }
491 
492 /*
493  * Process _Q events that might have accumulated in the EC.
494  * Run with locked ec mutex.
495  */
496 static void acpi_ec_clear(struct acpi_ec *ec)
497 {
498 	int i, status;
499 	u8 value = 0;
500 
501 	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
502 		status = acpi_ec_query(ec, &value);
503 		if (status || !value)
504 			break;
505 	}
506 	if (unlikely(i == ACPI_EC_CLEAR_MAX))
507 		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
508 	else
509 		pr_info("%d stale EC events cleared\n", i);
510 }
511 
512 static void acpi_ec_enable_event(struct acpi_ec *ec)
513 {
514 	unsigned long flags;
515 
516 	spin_lock_irqsave(&ec->lock, flags);
517 	if (acpi_ec_started(ec))
518 		__acpi_ec_enable_event(ec);
519 	spin_unlock_irqrestore(&ec->lock, flags);
520 
521 	/* Drain additional events if hardware requires that */
522 	if (EC_FLAGS_CLEAR_ON_RESUME)
523 		acpi_ec_clear(ec);
524 }
525 
526 #ifdef CONFIG_PM_SLEEP
527 static bool acpi_ec_query_flushed(struct acpi_ec *ec)
528 {
529 	bool flushed;
530 	unsigned long flags;
531 
532 	spin_lock_irqsave(&ec->lock, flags);
533 	flushed = !ec->nr_pending_queries;
534 	spin_unlock_irqrestore(&ec->lock, flags);
535 	return flushed;
536 }
537 
538 static void __acpi_ec_flush_event(struct acpi_ec *ec)
539 {
540 	/*
541 	 * When ec_freeze_events is true, we need to flush events in
542 	 * the proper position before entering the noirq stage.
543 	 */
544 	wait_event(ec->wait, acpi_ec_query_flushed(ec));
545 	if (ec_query_wq)
546 		flush_workqueue(ec_query_wq);
547 }
548 
549 static void acpi_ec_disable_event(struct acpi_ec *ec)
550 {
551 	unsigned long flags;
552 
553 	spin_lock_irqsave(&ec->lock, flags);
554 	__acpi_ec_disable_event(ec);
555 	spin_unlock_irqrestore(&ec->lock, flags);
556 	__acpi_ec_flush_event(ec);
557 }
558 
559 void acpi_ec_flush_work(void)
560 {
561 	if (first_ec)
562 		__acpi_ec_flush_event(first_ec);
563 
564 	flush_scheduled_work();
565 }
566 #endif /* CONFIG_PM_SLEEP */
567 
568 static bool acpi_ec_guard_event(struct acpi_ec *ec)
569 {
570 	bool guarded = true;
571 	unsigned long flags;
572 
573 	spin_lock_irqsave(&ec->lock, flags);
574 	/*
575 	 * If firmware SCI_EVT clearing timing is "event", we actually
576 	 * don't know when the SCI_EVT will be cleared by firmware after
577 	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
578 	 * acceptable period.
579 	 *
580 	 * The guarding period begins when EC_FLAGS_QUERY_PENDING is
581 	 * flagged, which means SCI_EVT check has just been performed.
582 	 * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
583 	 * guarding should have already been performed (via
584 	 * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
585 	 * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
586 	 * ACPI_EC_COMMAND_POLL state immediately.
587 	 */
588 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
589 	    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
590 	    !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
591 	    (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
592 		guarded = false;
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 	if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
625 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
626 		    flag == ACPI_EC_COMMAND_POLL)
627 			acpi_ec_complete_query(ec);
628 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
629 		    flag == ACPI_EC_COMMAND_COMPLETE)
630 			acpi_ec_complete_query(ec);
631 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
632 		    flag == ACPI_EC_COMMAND_COMPLETE)
633 			set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
634 	}
635 }
636 
637 static void advance_transaction(struct acpi_ec *ec)
638 {
639 	struct transaction *t;
640 	u8 status;
641 	bool wakeup = false;
642 
643 	ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
644 		   smp_processor_id());
645 	/*
646 	 * By always clearing STS before handling all indications, we can
647 	 * ensure a hardware STS 0->1 change after this clearing can always
648 	 * trigger a GPE interrupt.
649 	 */
650 	acpi_ec_clear_gpe(ec);
651 	status = acpi_ec_read_status(ec);
652 	t = ec->curr;
653 	/*
654 	 * Another IRQ or a guarded polling mode advancement is detected,
655 	 * the next QR_EC submission is then allowed.
656 	 */
657 	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
658 		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
659 		    (!ec->nr_pending_queries ||
660 		     test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
661 			clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
662 			acpi_ec_complete_query(ec);
663 		}
664 	}
665 	if (!t)
666 		goto err;
667 	if (t->flags & ACPI_EC_COMMAND_POLL) {
668 		if (t->wlen > t->wi) {
669 			if ((status & ACPI_EC_FLAG_IBF) == 0)
670 				acpi_ec_write_data(ec, t->wdata[t->wi++]);
671 			else
672 				goto err;
673 		} else if (t->rlen > t->ri) {
674 			if ((status & ACPI_EC_FLAG_OBF) == 1) {
675 				t->rdata[t->ri++] = acpi_ec_read_data(ec);
676 				if (t->rlen == t->ri) {
677 					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
678 					if (t->command == ACPI_EC_COMMAND_QUERY)
679 						ec_dbg_evt("Command(%s) completed by hardware",
680 							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
681 					wakeup = true;
682 				}
683 			} else
684 				goto err;
685 		} else if (t->wlen == t->wi &&
686 			   (status & ACPI_EC_FLAG_IBF) == 0) {
687 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
688 			wakeup = true;
689 		}
690 		goto out;
691 	} else {
692 		if (EC_FLAGS_QUERY_HANDSHAKE &&
693 		    !(status & ACPI_EC_FLAG_SCI) &&
694 		    (t->command == ACPI_EC_COMMAND_QUERY)) {
695 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
696 			t->rdata[t->ri++] = 0x00;
697 			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
698 			ec_dbg_evt("Command(%s) completed by software",
699 				   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
700 			wakeup = true;
701 		} else if ((status & ACPI_EC_FLAG_IBF) == 0) {
702 			acpi_ec_write_cmd(ec, t->command);
703 			ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
704 		} else
705 			goto err;
706 		goto out;
707 	}
708 err:
709 	/*
710 	 * If SCI bit is set, then don't think it's a false IRQ
711 	 * otherwise will take a not handled IRQ as a false one.
712 	 */
713 	if (!(status & ACPI_EC_FLAG_SCI)) {
714 		if (in_interrupt() && t) {
715 			if (t->irq_count < ec_storm_threshold)
716 				++t->irq_count;
717 			/* Allow triggering on 0 threshold */
718 			if (t->irq_count == ec_storm_threshold)
719 				acpi_ec_mask_gpe(ec);
720 		}
721 	}
722 out:
723 	if (status & ACPI_EC_FLAG_SCI)
724 		acpi_ec_submit_query(ec);
725 	if (wakeup && in_interrupt())
726 		wake_up(&ec->wait);
727 }
728 
729 static void start_transaction(struct acpi_ec *ec)
730 {
731 	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
732 	ec->curr->flags = 0;
733 }
734 
735 static int ec_guard(struct acpi_ec *ec)
736 {
737 	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
738 	unsigned long timeout = ec->timestamp + guard;
739 
740 	/* Ensure guarding period before polling EC status */
741 	do {
742 		if (ec->busy_polling) {
743 			/* Perform busy polling */
744 			if (ec_transaction_completed(ec))
745 				return 0;
746 			udelay(jiffies_to_usecs(guard));
747 		} else {
748 			/*
749 			 * Perform wait polling
750 			 * 1. Wait the transaction to be completed by the
751 			 *    GPE handler after the transaction enters
752 			 *    ACPI_EC_COMMAND_POLL state.
753 			 * 2. A special guarding logic is also required
754 			 *    for event clearing mode "event" before the
755 			 *    transaction enters ACPI_EC_COMMAND_POLL
756 			 *    state.
757 			 */
758 			if (!ec_transaction_polled(ec) &&
759 			    !acpi_ec_guard_event(ec))
760 				break;
761 			if (wait_event_timeout(ec->wait,
762 					       ec_transaction_completed(ec),
763 					       guard))
764 				return 0;
765 		}
766 	} while (time_before(jiffies, timeout));
767 	return -ETIME;
768 }
769 
770 static int ec_poll(struct acpi_ec *ec)
771 {
772 	unsigned long flags;
773 	int repeat = 5; /* number of command restarts */
774 
775 	while (repeat--) {
776 		unsigned long delay = jiffies +
777 			msecs_to_jiffies(ec_delay);
778 		do {
779 			if (!ec_guard(ec))
780 				return 0;
781 			spin_lock_irqsave(&ec->lock, flags);
782 			advance_transaction(ec);
783 			spin_unlock_irqrestore(&ec->lock, flags);
784 		} while (time_before(jiffies, delay));
785 		pr_debug("controller reset, restart transaction\n");
786 		spin_lock_irqsave(&ec->lock, flags);
787 		start_transaction(ec);
788 		spin_unlock_irqrestore(&ec->lock, flags);
789 	}
790 	return -ETIME;
791 }
792 
793 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
794 					struct transaction *t)
795 {
796 	unsigned long tmp;
797 	int ret = 0;
798 
799 	/* start transaction */
800 	spin_lock_irqsave(&ec->lock, tmp);
801 	/* Enable GPE for command processing (IBF=0/OBF=1) */
802 	if (!acpi_ec_submit_flushable_request(ec)) {
803 		ret = -EINVAL;
804 		goto unlock;
805 	}
806 	ec_dbg_ref(ec, "Increase command");
807 	/* following two actions should be kept atomic */
808 	ec->curr = t;
809 	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
810 	start_transaction(ec);
811 	spin_unlock_irqrestore(&ec->lock, tmp);
812 
813 	ret = ec_poll(ec);
814 
815 	spin_lock_irqsave(&ec->lock, tmp);
816 	if (t->irq_count == ec_storm_threshold)
817 		acpi_ec_unmask_gpe(ec);
818 	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
819 	ec->curr = NULL;
820 	/* Disable GPE for command processing (IBF=0/OBF=1) */
821 	acpi_ec_complete_request(ec);
822 	ec_dbg_ref(ec, "Decrease command");
823 unlock:
824 	spin_unlock_irqrestore(&ec->lock, tmp);
825 	return ret;
826 }
827 
828 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
829 {
830 	int status;
831 	u32 glk;
832 
833 	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
834 		return -EINVAL;
835 	if (t->rdata)
836 		memset(t->rdata, 0, t->rlen);
837 
838 	mutex_lock(&ec->mutex);
839 	if (ec->global_lock) {
840 		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
841 		if (ACPI_FAILURE(status)) {
842 			status = -ENODEV;
843 			goto unlock;
844 		}
845 	}
846 
847 	status = acpi_ec_transaction_unlocked(ec, t);
848 
849 	if (ec->global_lock)
850 		acpi_release_global_lock(glk);
851 unlock:
852 	mutex_unlock(&ec->mutex);
853 	return status;
854 }
855 
856 static int acpi_ec_burst_enable(struct acpi_ec *ec)
857 {
858 	u8 d;
859 	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
860 				.wdata = NULL, .rdata = &d,
861 				.wlen = 0, .rlen = 1};
862 
863 	return acpi_ec_transaction(ec, &t);
864 }
865 
866 static int acpi_ec_burst_disable(struct acpi_ec *ec)
867 {
868 	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
869 				.wdata = NULL, .rdata = NULL,
870 				.wlen = 0, .rlen = 0};
871 
872 	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
873 				acpi_ec_transaction(ec, &t) : 0;
874 }
875 
876 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
877 {
878 	int result;
879 	u8 d;
880 	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
881 				.wdata = &address, .rdata = &d,
882 				.wlen = 1, .rlen = 1};
883 
884 	result = acpi_ec_transaction(ec, &t);
885 	*data = d;
886 	return result;
887 }
888 
889 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
890 {
891 	u8 wdata[2] = { address, data };
892 	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
893 				.wdata = wdata, .rdata = NULL,
894 				.wlen = 2, .rlen = 0};
895 
896 	return acpi_ec_transaction(ec, &t);
897 }
898 
899 int ec_read(u8 addr, u8 *val)
900 {
901 	int err;
902 	u8 temp_data;
903 
904 	if (!first_ec)
905 		return -ENODEV;
906 
907 	err = acpi_ec_read(first_ec, addr, &temp_data);
908 
909 	if (!err) {
910 		*val = temp_data;
911 		return 0;
912 	}
913 	return err;
914 }
915 EXPORT_SYMBOL(ec_read);
916 
917 int ec_write(u8 addr, u8 val)
918 {
919 	int err;
920 
921 	if (!first_ec)
922 		return -ENODEV;
923 
924 	err = acpi_ec_write(first_ec, addr, val);
925 
926 	return err;
927 }
928 EXPORT_SYMBOL(ec_write);
929 
930 int ec_transaction(u8 command,
931 		   const u8 *wdata, unsigned wdata_len,
932 		   u8 *rdata, unsigned rdata_len)
933 {
934 	struct transaction t = {.command = command,
935 				.wdata = wdata, .rdata = rdata,
936 				.wlen = wdata_len, .rlen = rdata_len};
937 
938 	if (!first_ec)
939 		return -ENODEV;
940 
941 	return acpi_ec_transaction(first_ec, &t);
942 }
943 EXPORT_SYMBOL(ec_transaction);
944 
945 /* Get the handle to the EC device */
946 acpi_handle ec_get_handle(void)
947 {
948 	if (!first_ec)
949 		return NULL;
950 	return first_ec->handle;
951 }
952 EXPORT_SYMBOL(ec_get_handle);
953 
954 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
955 {
956 	unsigned long flags;
957 
958 	spin_lock_irqsave(&ec->lock, flags);
959 	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
960 		ec_dbg_drv("Starting EC");
961 		/* Enable GPE for event processing (SCI_EVT=1) */
962 		if (!resuming) {
963 			acpi_ec_submit_request(ec);
964 			ec_dbg_ref(ec, "Increase driver");
965 		}
966 		ec_log_drv("EC started");
967 	}
968 	spin_unlock_irqrestore(&ec->lock, flags);
969 }
970 
971 static bool acpi_ec_stopped(struct acpi_ec *ec)
972 {
973 	unsigned long flags;
974 	bool flushed;
975 
976 	spin_lock_irqsave(&ec->lock, flags);
977 	flushed = acpi_ec_flushed(ec);
978 	spin_unlock_irqrestore(&ec->lock, flags);
979 	return flushed;
980 }
981 
982 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
983 {
984 	unsigned long flags;
985 
986 	spin_lock_irqsave(&ec->lock, flags);
987 	if (acpi_ec_started(ec)) {
988 		ec_dbg_drv("Stopping EC");
989 		set_bit(EC_FLAGS_STOPPED, &ec->flags);
990 		spin_unlock_irqrestore(&ec->lock, flags);
991 		wait_event(ec->wait, acpi_ec_stopped(ec));
992 		spin_lock_irqsave(&ec->lock, flags);
993 		/* Disable GPE for event processing (SCI_EVT=1) */
994 		if (!suspending) {
995 			acpi_ec_complete_request(ec);
996 			ec_dbg_ref(ec, "Decrease driver");
997 		} else if (!ec_freeze_events)
998 			__acpi_ec_disable_event(ec);
999 		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1000 		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1001 		ec_log_drv("EC stopped");
1002 	}
1003 	spin_unlock_irqrestore(&ec->lock, flags);
1004 }
1005 
1006 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1007 {
1008 	unsigned long flags;
1009 
1010 	spin_lock_irqsave(&ec->lock, flags);
1011 	ec->busy_polling = true;
1012 	ec->polling_guard = 0;
1013 	ec_log_drv("interrupt blocked");
1014 	spin_unlock_irqrestore(&ec->lock, flags);
1015 }
1016 
1017 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1018 {
1019 	unsigned long flags;
1020 
1021 	spin_lock_irqsave(&ec->lock, flags);
1022 	ec->busy_polling = ec_busy_polling;
1023 	ec->polling_guard = ec_polling_guard;
1024 	ec_log_drv("interrupt unblocked");
1025 	spin_unlock_irqrestore(&ec->lock, flags);
1026 }
1027 
1028 void acpi_ec_block_transactions(void)
1029 {
1030 	struct acpi_ec *ec = first_ec;
1031 
1032 	if (!ec)
1033 		return;
1034 
1035 	mutex_lock(&ec->mutex);
1036 	/* Prevent transactions from being carried out */
1037 	acpi_ec_stop(ec, true);
1038 	mutex_unlock(&ec->mutex);
1039 }
1040 
1041 void acpi_ec_unblock_transactions(void)
1042 {
1043 	/*
1044 	 * Allow transactions to happen again (this function is called from
1045 	 * atomic context during wakeup, so we don't need to acquire the mutex).
1046 	 */
1047 	if (first_ec)
1048 		acpi_ec_start(first_ec, true);
1049 }
1050 
1051 void acpi_ec_mark_gpe_for_wake(void)
1052 {
1053 	if (first_ec && !ec_no_wakeup)
1054 		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1055 }
1056 
1057 void acpi_ec_set_gpe_wake_mask(u8 action)
1058 {
1059 	if (first_ec && !ec_no_wakeup)
1060 		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1061 }
1062 
1063 void acpi_ec_dispatch_gpe(void)
1064 {
1065 	if (first_ec)
1066 		acpi_dispatch_gpe(NULL, first_ec->gpe);
1067 }
1068 
1069 /* --------------------------------------------------------------------------
1070                                 Event Management
1071    -------------------------------------------------------------------------- */
1072 static struct acpi_ec_query_handler *
1073 acpi_ec_get_query_handler(struct acpi_ec_query_handler *handler)
1074 {
1075 	if (handler)
1076 		kref_get(&handler->kref);
1077 	return handler;
1078 }
1079 
1080 static struct acpi_ec_query_handler *
1081 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1082 {
1083 	struct acpi_ec_query_handler *handler;
1084 	bool found = false;
1085 
1086 	mutex_lock(&ec->mutex);
1087 	list_for_each_entry(handler, &ec->list, node) {
1088 		if (value == handler->query_bit) {
1089 			found = true;
1090 			break;
1091 		}
1092 	}
1093 	mutex_unlock(&ec->mutex);
1094 	return found ? acpi_ec_get_query_handler(handler) : NULL;
1095 }
1096 
1097 static void acpi_ec_query_handler_release(struct kref *kref)
1098 {
1099 	struct acpi_ec_query_handler *handler =
1100 		container_of(kref, struct acpi_ec_query_handler, kref);
1101 
1102 	kfree(handler);
1103 }
1104 
1105 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1106 {
1107 	kref_put(&handler->kref, acpi_ec_query_handler_release);
1108 }
1109 
1110 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1111 			      acpi_handle handle, acpi_ec_query_func func,
1112 			      void *data)
1113 {
1114 	struct acpi_ec_query_handler *handler =
1115 	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1116 
1117 	if (!handler)
1118 		return -ENOMEM;
1119 
1120 	handler->query_bit = query_bit;
1121 	handler->handle = handle;
1122 	handler->func = func;
1123 	handler->data = data;
1124 	mutex_lock(&ec->mutex);
1125 	kref_init(&handler->kref);
1126 	list_add(&handler->node, &ec->list);
1127 	mutex_unlock(&ec->mutex);
1128 	return 0;
1129 }
1130 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1131 
1132 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1133 					  bool remove_all, u8 query_bit)
1134 {
1135 	struct acpi_ec_query_handler *handler, *tmp;
1136 	LIST_HEAD(free_list);
1137 
1138 	mutex_lock(&ec->mutex);
1139 	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1140 		if (remove_all || query_bit == handler->query_bit) {
1141 			list_del_init(&handler->node);
1142 			list_add(&handler->node, &free_list);
1143 		}
1144 	}
1145 	mutex_unlock(&ec->mutex);
1146 	list_for_each_entry_safe(handler, tmp, &free_list, node)
1147 		acpi_ec_put_query_handler(handler);
1148 }
1149 
1150 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1151 {
1152 	acpi_ec_remove_query_handlers(ec, false, query_bit);
1153 }
1154 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1155 
1156 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1157 {
1158 	struct acpi_ec_query *q;
1159 	struct transaction *t;
1160 
1161 	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1162 	if (!q)
1163 		return NULL;
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 	return q;
1170 }
1171 
1172 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1173 {
1174 	if (q) {
1175 		if (q->handler)
1176 			acpi_ec_put_query_handler(q->handler);
1177 		kfree(q);
1178 	}
1179 }
1180 
1181 static void acpi_ec_event_processor(struct work_struct *work)
1182 {
1183 	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1184 	struct acpi_ec_query_handler *handler = q->handler;
1185 
1186 	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1187 	if (handler->func)
1188 		handler->func(handler->data);
1189 	else if (handler->handle)
1190 		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1191 	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1192 	acpi_ec_delete_query(q);
1193 }
1194 
1195 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1196 {
1197 	u8 value = 0;
1198 	int result;
1199 	struct acpi_ec_query *q;
1200 
1201 	q = acpi_ec_create_query(&value);
1202 	if (!q)
1203 		return -ENOMEM;
1204 
1205 	/*
1206 	 * Query the EC to find out which _Qxx method we need to evaluate.
1207 	 * Note that successful completion of the query causes the ACPI_EC_SCI
1208 	 * bit to be cleared (and thus clearing the interrupt source).
1209 	 */
1210 	result = acpi_ec_transaction(ec, &q->transaction);
1211 	if (!value)
1212 		result = -ENODATA;
1213 	if (result)
1214 		goto err_exit;
1215 
1216 	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1217 	if (!q->handler) {
1218 		result = -ENODATA;
1219 		goto err_exit;
1220 	}
1221 
1222 	/*
1223 	 * It is reported that _Qxx are evaluated in a parallel way on
1224 	 * Windows:
1225 	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1226 	 *
1227 	 * Put this log entry before schedule_work() in order to make
1228 	 * it appearing before any other log entries occurred during the
1229 	 * work queue execution.
1230 	 */
1231 	ec_dbg_evt("Query(0x%02x) scheduled", value);
1232 	if (!queue_work(ec_query_wq, &q->work)) {
1233 		ec_dbg_evt("Query(0x%02x) overlapped", value);
1234 		result = -EBUSY;
1235 	}
1236 
1237 err_exit:
1238 	if (result)
1239 		acpi_ec_delete_query(q);
1240 	if (data)
1241 		*data = value;
1242 	return result;
1243 }
1244 
1245 static void acpi_ec_check_event(struct acpi_ec *ec)
1246 {
1247 	unsigned long flags;
1248 
1249 	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1250 		if (ec_guard(ec)) {
1251 			spin_lock_irqsave(&ec->lock, flags);
1252 			/*
1253 			 * Take care of the SCI_EVT unless no one else is
1254 			 * taking care of it.
1255 			 */
1256 			if (!ec->curr)
1257 				advance_transaction(ec);
1258 			spin_unlock_irqrestore(&ec->lock, flags);
1259 		}
1260 	}
1261 }
1262 
1263 static void acpi_ec_event_handler(struct work_struct *work)
1264 {
1265 	unsigned long flags;
1266 	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1267 
1268 	ec_dbg_evt("Event started");
1269 
1270 	spin_lock_irqsave(&ec->lock, flags);
1271 	while (ec->nr_pending_queries) {
1272 		spin_unlock_irqrestore(&ec->lock, flags);
1273 		(void)acpi_ec_query(ec, NULL);
1274 		spin_lock_irqsave(&ec->lock, flags);
1275 		ec->nr_pending_queries--;
1276 		/*
1277 		 * Before exit, make sure that this work item can be
1278 		 * scheduled again. There might be QR_EC failures, leaving
1279 		 * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1280 		 * item from being scheduled again.
1281 		 */
1282 		if (!ec->nr_pending_queries) {
1283 			if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1284 			    ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1285 				acpi_ec_complete_query(ec);
1286 		}
1287 	}
1288 	spin_unlock_irqrestore(&ec->lock, flags);
1289 
1290 	ec_dbg_evt("Event stopped");
1291 
1292 	acpi_ec_check_event(ec);
1293 }
1294 
1295 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1296 	u32 gpe_number, void *data)
1297 {
1298 	unsigned long flags;
1299 	struct acpi_ec *ec = data;
1300 
1301 	spin_lock_irqsave(&ec->lock, flags);
1302 	advance_transaction(ec);
1303 	spin_unlock_irqrestore(&ec->lock, flags);
1304 	return ACPI_INTERRUPT_HANDLED;
1305 }
1306 
1307 /* --------------------------------------------------------------------------
1308  *                           Address Space Management
1309  * -------------------------------------------------------------------------- */
1310 
1311 static acpi_status
1312 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1313 		      u32 bits, u64 *value64,
1314 		      void *handler_context, void *region_context)
1315 {
1316 	struct acpi_ec *ec = handler_context;
1317 	int result = 0, i, bytes = bits / 8;
1318 	u8 *value = (u8 *)value64;
1319 
1320 	if ((address > 0xFF) || !value || !handler_context)
1321 		return AE_BAD_PARAMETER;
1322 
1323 	if (function != ACPI_READ && function != ACPI_WRITE)
1324 		return AE_BAD_PARAMETER;
1325 
1326 	if (ec->busy_polling || bits > 8)
1327 		acpi_ec_burst_enable(ec);
1328 
1329 	for (i = 0; i < bytes; ++i, ++address, ++value)
1330 		result = (function == ACPI_READ) ?
1331 			acpi_ec_read(ec, address, value) :
1332 			acpi_ec_write(ec, address, *value);
1333 
1334 	if (ec->busy_polling || bits > 8)
1335 		acpi_ec_burst_disable(ec);
1336 
1337 	switch (result) {
1338 	case -EINVAL:
1339 		return AE_BAD_PARAMETER;
1340 	case -ENODEV:
1341 		return AE_NOT_FOUND;
1342 	case -ETIME:
1343 		return AE_TIME;
1344 	default:
1345 		return AE_OK;
1346 	}
1347 }
1348 
1349 /* --------------------------------------------------------------------------
1350  *                             Driver Interface
1351  * -------------------------------------------------------------------------- */
1352 
1353 static acpi_status
1354 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1355 
1356 static void acpi_ec_free(struct acpi_ec *ec)
1357 {
1358 	if (first_ec == ec)
1359 		first_ec = NULL;
1360 	if (boot_ec == ec)
1361 		boot_ec = NULL;
1362 	kfree(ec);
1363 }
1364 
1365 static struct acpi_ec *acpi_ec_alloc(void)
1366 {
1367 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1368 
1369 	if (!ec)
1370 		return NULL;
1371 	mutex_init(&ec->mutex);
1372 	init_waitqueue_head(&ec->wait);
1373 	INIT_LIST_HEAD(&ec->list);
1374 	spin_lock_init(&ec->lock);
1375 	INIT_WORK(&ec->work, acpi_ec_event_handler);
1376 	ec->timestamp = jiffies;
1377 	ec->busy_polling = true;
1378 	ec->polling_guard = 0;
1379 	return ec;
1380 }
1381 
1382 static acpi_status
1383 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1384 			       void *context, void **return_value)
1385 {
1386 	char node_name[5];
1387 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1388 	struct acpi_ec *ec = context;
1389 	int value = 0;
1390 	acpi_status status;
1391 
1392 	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1393 
1394 	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1395 		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1396 	return AE_OK;
1397 }
1398 
1399 static acpi_status
1400 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1401 {
1402 	acpi_status status;
1403 	unsigned long long tmp = 0;
1404 	struct acpi_ec *ec = context;
1405 
1406 	/* clear addr values, ec_parse_io_ports depend on it */
1407 	ec->command_addr = ec->data_addr = 0;
1408 
1409 	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1410 				     ec_parse_io_ports, ec);
1411 	if (ACPI_FAILURE(status))
1412 		return status;
1413 	if (ec->data_addr == 0 || ec->command_addr == 0)
1414 		return AE_OK;
1415 
1416 	if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1417 		/*
1418 		 * Always inherit the GPE number setting from the ECDT
1419 		 * EC.
1420 		 */
1421 		ec->gpe = boot_ec->gpe;
1422 	} else {
1423 		/* Get GPE bit assignment (EC events). */
1424 		/* TODO: Add support for _GPE returning a package */
1425 		status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1426 		if (ACPI_FAILURE(status))
1427 			return status;
1428 		ec->gpe = tmp;
1429 	}
1430 	/* Use the global lock for all EC transactions? */
1431 	tmp = 0;
1432 	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1433 	ec->global_lock = tmp;
1434 	ec->handle = handle;
1435 	return AE_CTRL_TERMINATE;
1436 }
1437 
1438 /*
1439  * Note: This function returns an error code only when the address space
1440  *       handler is not installed, which means "not able to handle
1441  *       transactions".
1442  */
1443 static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
1444 {
1445 	acpi_status status;
1446 
1447 	acpi_ec_start(ec, false);
1448 
1449 	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1450 		acpi_ec_enter_noirq(ec);
1451 		status = acpi_install_address_space_handler(ec->handle,
1452 							    ACPI_ADR_SPACE_EC,
1453 							    &acpi_ec_space_handler,
1454 							    NULL, ec);
1455 		if (ACPI_FAILURE(status)) {
1456 			if (status == AE_NOT_FOUND) {
1457 				/*
1458 				 * Maybe OS fails in evaluating the _REG
1459 				 * object. The AE_NOT_FOUND error will be
1460 				 * ignored and OS * continue to initialize
1461 				 * EC.
1462 				 */
1463 				pr_err("Fail in evaluating the _REG object"
1464 					" of EC device. Broken bios is suspected.\n");
1465 			} else {
1466 				acpi_ec_stop(ec, false);
1467 				return -ENODEV;
1468 			}
1469 		}
1470 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1471 	}
1472 
1473 	if (!handle_events)
1474 		return 0;
1475 
1476 	if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1477 		/* Find and register all query methods */
1478 		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1479 				    acpi_ec_register_query_methods,
1480 				    NULL, ec, NULL);
1481 		set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1482 	}
1483 	if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1484 		status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1485 					  ACPI_GPE_EDGE_TRIGGERED,
1486 					  &acpi_ec_gpe_handler, ec);
1487 		/* This is not fatal as we can poll EC events */
1488 		if (ACPI_SUCCESS(status)) {
1489 			set_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1490 			acpi_ec_leave_noirq(ec);
1491 			if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1492 			    ec->reference_count >= 1)
1493 				acpi_ec_enable_gpe(ec, true);
1494 		}
1495 	}
1496 	/* EC is fully operational, allow queries */
1497 	acpi_ec_enable_event(ec);
1498 
1499 	return 0;
1500 }
1501 
1502 static void ec_remove_handlers(struct acpi_ec *ec)
1503 {
1504 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1505 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1506 					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1507 			pr_err("failed to remove space handler\n");
1508 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1509 	}
1510 
1511 	/*
1512 	 * Stops handling the EC transactions after removing the operation
1513 	 * region handler. This is required because _REG(DISCONNECT)
1514 	 * invoked during the removal can result in new EC transactions.
1515 	 *
1516 	 * Flushes the EC requests and thus disables the GPE before
1517 	 * removing the GPE handler. This is required by the current ACPICA
1518 	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1519 	 * it is indicated but there is no way to handle it. So the drivers
1520 	 * must disable the GPEs prior to removing the GPE handlers.
1521 	 */
1522 	acpi_ec_stop(ec, false);
1523 
1524 	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
1525 		if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1526 					&acpi_ec_gpe_handler)))
1527 			pr_err("failed to remove gpe handler\n");
1528 		clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
1529 	}
1530 	if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
1531 		acpi_ec_remove_query_handlers(ec, true, 0);
1532 		clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
1533 	}
1534 }
1535 
1536 static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
1537 {
1538 	int ret;
1539 
1540 	ret = ec_install_handlers(ec, handle_events);
1541 	if (ret)
1542 		return ret;
1543 
1544 	/* First EC capable of handling transactions */
1545 	if (!first_ec) {
1546 		first_ec = ec;
1547 		acpi_handle_info(first_ec->handle, "Used as first EC\n");
1548 	}
1549 
1550 	acpi_handle_info(ec->handle,
1551 			 "GPE=0x%x, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
1552 			 ec->gpe, ec->command_addr, ec->data_addr);
1553 	return ret;
1554 }
1555 
1556 static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
1557 {
1558 	struct acpi_table_ecdt *ecdt_ptr;
1559 	acpi_status status;
1560 	acpi_handle handle;
1561 
1562 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1563 				(struct acpi_table_header **)&ecdt_ptr);
1564 	if (ACPI_FAILURE(status))
1565 		return false;
1566 
1567 	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1568 	if (ACPI_FAILURE(status))
1569 		return false;
1570 
1571 	*phandle = handle;
1572 	return true;
1573 }
1574 
1575 static int acpi_ec_add(struct acpi_device *device)
1576 {
1577 	struct acpi_ec *ec = NULL;
1578 	bool dep_update = true;
1579 	acpi_status status;
1580 	int ret;
1581 
1582 	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1583 	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1584 
1585 	if (!strcmp(acpi_device_hid(device), ACPI_ECDT_HID)) {
1586 		boot_ec_is_ecdt = true;
1587 		ec = boot_ec;
1588 		dep_update = false;
1589 	} else {
1590 		ec = acpi_ec_alloc();
1591 		if (!ec)
1592 			return -ENOMEM;
1593 
1594 		status = ec_parse_device(device->handle, 0, ec, NULL);
1595 		if (status != AE_CTRL_TERMINATE) {
1596 			ret = -EINVAL;
1597 			goto err_alloc;
1598 		}
1599 
1600 		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1601 		    ec->data_addr == boot_ec->data_addr) {
1602 			boot_ec_is_ecdt = false;
1603 			/*
1604 			 * Trust PNP0C09 namespace location rather than
1605 			 * ECDT ID. But trust ECDT GPE rather than _GPE
1606 			 * because of ASUS quirks, so do not change
1607 			 * boot_ec->gpe to ec->gpe.
1608 			 */
1609 			boot_ec->handle = ec->handle;
1610 			acpi_handle_debug(ec->handle, "duplicated.\n");
1611 			acpi_ec_free(ec);
1612 			ec = boot_ec;
1613 		}
1614 	}
1615 
1616 	ret = acpi_ec_setup(ec, true);
1617 	if (ret)
1618 		goto err_query;
1619 
1620 	if (ec == boot_ec)
1621 		acpi_handle_info(boot_ec->handle,
1622 				 "Boot %s EC used to handle transactions and events\n",
1623 				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1624 
1625 	device->driver_data = ec;
1626 
1627 	ret = !!request_region(ec->data_addr, 1, "EC data");
1628 	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1629 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1630 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1631 
1632 	if (dep_update) {
1633 		/* Reprobe devices depending on the EC */
1634 		acpi_walk_dep_device_list(ec->handle);
1635 	}
1636 	acpi_handle_debug(ec->handle, "enumerated.\n");
1637 	return 0;
1638 
1639 err_query:
1640 	if (ec != boot_ec)
1641 		acpi_ec_remove_query_handlers(ec, true, 0);
1642 err_alloc:
1643 	if (ec != boot_ec)
1644 		acpi_ec_free(ec);
1645 	return ret;
1646 }
1647 
1648 static int acpi_ec_remove(struct acpi_device *device)
1649 {
1650 	struct acpi_ec *ec;
1651 
1652 	if (!device)
1653 		return -EINVAL;
1654 
1655 	ec = acpi_driver_data(device);
1656 	release_region(ec->data_addr, 1);
1657 	release_region(ec->command_addr, 1);
1658 	device->driver_data = NULL;
1659 	if (ec != boot_ec) {
1660 		ec_remove_handlers(ec);
1661 		acpi_ec_free(ec);
1662 	}
1663 	return 0;
1664 }
1665 
1666 static acpi_status
1667 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1668 {
1669 	struct acpi_ec *ec = context;
1670 
1671 	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1672 		return AE_OK;
1673 
1674 	/*
1675 	 * The first address region returned is the data port, and
1676 	 * the second address region returned is the status/command
1677 	 * port.
1678 	 */
1679 	if (ec->data_addr == 0)
1680 		ec->data_addr = resource->data.io.minimum;
1681 	else if (ec->command_addr == 0)
1682 		ec->command_addr = resource->data.io.minimum;
1683 	else
1684 		return AE_CTRL_TERMINATE;
1685 
1686 	return AE_OK;
1687 }
1688 
1689 static const struct acpi_device_id ec_device_ids[] = {
1690 	{"PNP0C09", 0},
1691 	{ACPI_ECDT_HID, 0},
1692 	{"", 0},
1693 };
1694 
1695 /*
1696  * This function is not Windows-compatible as Windows never enumerates the
1697  * namespace EC before the main ACPI device enumeration process. It is
1698  * retained for historical reason and will be deprecated in the future.
1699  */
1700 void __init acpi_ec_dsdt_probe(void)
1701 {
1702 	struct acpi_ec *ec;
1703 	acpi_status status;
1704 	int ret;
1705 
1706 	/*
1707 	 * If a platform has ECDT, there is no need to proceed as the
1708 	 * following probe is not a part of the ACPI device enumeration,
1709 	 * executing _STA is not safe, and thus this probe may risk of
1710 	 * picking up an invalid EC device.
1711 	 */
1712 	if (boot_ec)
1713 		return;
1714 
1715 	ec = acpi_ec_alloc();
1716 	if (!ec)
1717 		return;
1718 
1719 	/*
1720 	 * At this point, the namespace is initialized, so start to find
1721 	 * the namespace objects.
1722 	 */
1723 	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1724 	if (ACPI_FAILURE(status) || !ec->handle) {
1725 		acpi_ec_free(ec);
1726 		return;
1727 	}
1728 
1729 	/*
1730 	 * When the DSDT EC is available, always re-configure boot EC to
1731 	 * have _REG evaluated. _REG can only be evaluated after the
1732 	 * namespace initialization.
1733 	 * At this point, the GPE is not fully initialized, so do not to
1734 	 * handle the events.
1735 	 */
1736 	ret = acpi_ec_setup(ec, false);
1737 	if (ret) {
1738 		acpi_ec_free(ec);
1739 		return;
1740 	}
1741 
1742 	boot_ec = ec;
1743 
1744 	acpi_handle_info(ec->handle,
1745 			 "Boot DSDT EC used to handle transactions\n");
1746 }
1747 
1748 /*
1749  * If the DSDT EC is not functioning, we still need to prepare a fully
1750  * functioning ECDT EC first in order to handle the events.
1751  * https://bugzilla.kernel.org/show_bug.cgi?id=115021
1752  */
1753 static int __init acpi_ec_ecdt_start(void)
1754 {
1755 	acpi_handle handle;
1756 
1757 	if (!boot_ec)
1758 		return -ENODEV;
1759 	/* In case acpi_ec_ecdt_start() is called after acpi_ec_add() */
1760 	if (!boot_ec_is_ecdt)
1761 		return -ENODEV;
1762 
1763 	/*
1764 	 * At this point, the namespace and the GPE is initialized, so
1765 	 * start to find the namespace objects and handle the events.
1766 	 *
1767 	 * Note: ec->handle can be valid if this function is called after
1768 	 * acpi_ec_add(), hence the fast path.
1769 	 */
1770 	if (boot_ec->handle == ACPI_ROOT_OBJECT) {
1771 		if (!acpi_ec_ecdt_get_handle(&handle))
1772 			return -ENODEV;
1773 		boot_ec->handle = handle;
1774 	}
1775 
1776 	/* Register to ACPI bus with PM ops attached */
1777 	return acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1778 }
1779 
1780 #if 0
1781 /*
1782  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
1783  * set, for which case, we complete the QR_EC without issuing it to the
1784  * firmware.
1785  * https://bugzilla.kernel.org/show_bug.cgi?id=82611
1786  * https://bugzilla.kernel.org/show_bug.cgi?id=97381
1787  */
1788 static int ec_flag_query_handshake(const struct dmi_system_id *id)
1789 {
1790 	pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT set\n");
1791 	EC_FLAGS_QUERY_HANDSHAKE = 1;
1792 	return 0;
1793 }
1794 #endif
1795 
1796 /*
1797  * On some hardware it is necessary to clear events accumulated by the EC during
1798  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1799  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1800  *
1801  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1802  *
1803  * Ideally, the EC should also be instructed NOT to accumulate events during
1804  * sleep (which Windows seems to do somehow), but the interface to control this
1805  * behaviour is not known at this time.
1806  *
1807  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1808  * however it is very likely that other Samsung models are affected.
1809  *
1810  * On systems which don't accumulate _Q events during sleep, this extra check
1811  * should be harmless.
1812  */
1813 static int ec_clear_on_resume(const struct dmi_system_id *id)
1814 {
1815 	pr_debug("Detected system needing EC poll on resume.\n");
1816 	EC_FLAGS_CLEAR_ON_RESUME = 1;
1817 	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1818 	return 0;
1819 }
1820 
1821 /*
1822  * Some ECDTs contain wrong register addresses.
1823  * MSI MS-171F
1824  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1825  */
1826 static int ec_correct_ecdt(const struct dmi_system_id *id)
1827 {
1828 	pr_debug("Detected system needing ECDT address correction.\n");
1829 	EC_FLAGS_CORRECT_ECDT = 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, "ASUS X550VXK", {
1864 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1865 	DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1866 	{
1867 	ec_honor_ecdt_gpe, "ASUS X580VD", {
1868 	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1869 	DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1870 	{
1871 	ec_clear_on_resume, "Samsung hardware", {
1872 	DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1873 	{},
1874 };
1875 
1876 void __init acpi_ec_ecdt_probe(void)
1877 {
1878 	struct acpi_table_ecdt *ecdt_ptr;
1879 	struct acpi_ec *ec;
1880 	acpi_status status;
1881 	int ret;
1882 
1883 	/* Generate a boot ec context. */
1884 	dmi_check_system(ec_dmi_table);
1885 	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1886 				(struct acpi_table_header **)&ecdt_ptr);
1887 	if (ACPI_FAILURE(status))
1888 		return;
1889 
1890 	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1891 		/*
1892 		 * Asus X50GL:
1893 		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1894 		 */
1895 		return;
1896 	}
1897 
1898 	ec = acpi_ec_alloc();
1899 	if (!ec)
1900 		return;
1901 
1902 	if (EC_FLAGS_CORRECT_ECDT) {
1903 		ec->command_addr = ecdt_ptr->data.address;
1904 		ec->data_addr = ecdt_ptr->control.address;
1905 	} else {
1906 		ec->command_addr = ecdt_ptr->control.address;
1907 		ec->data_addr = ecdt_ptr->data.address;
1908 	}
1909 	ec->gpe = ecdt_ptr->gpe;
1910 	ec->handle = ACPI_ROOT_OBJECT;
1911 
1912 	/*
1913 	 * At this point, the namespace is not initialized, so do not find
1914 	 * the namespace objects, or handle the events.
1915 	 */
1916 	ret = acpi_ec_setup(ec, false);
1917 	if (ret) {
1918 		acpi_ec_free(ec);
1919 		return;
1920 	}
1921 
1922 	boot_ec = ec;
1923 	boot_ec_is_ecdt = true;
1924 
1925 	pr_info("Boot ECDT EC used to handle transactions\n");
1926 }
1927 
1928 #ifdef CONFIG_PM_SLEEP
1929 static int acpi_ec_suspend(struct device *dev)
1930 {
1931 	struct acpi_ec *ec =
1932 		acpi_driver_data(to_acpi_device(dev));
1933 
1934 	if (acpi_sleep_no_ec_events() && ec_freeze_events)
1935 		acpi_ec_disable_event(ec);
1936 	return 0;
1937 }
1938 
1939 static int acpi_ec_suspend_noirq(struct device *dev)
1940 {
1941 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1942 
1943 	/*
1944 	 * The SCI handler doesn't run at this point, so the GPE can be
1945 	 * masked at the low level without side effects.
1946 	 */
1947 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1948 	    ec->reference_count >= 1)
1949 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1950 
1951 	if (acpi_sleep_no_ec_events())
1952 		acpi_ec_enter_noirq(ec);
1953 
1954 	return 0;
1955 }
1956 
1957 static int acpi_ec_resume_noirq(struct device *dev)
1958 {
1959 	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1960 
1961 	if (acpi_sleep_no_ec_events())
1962 		acpi_ec_leave_noirq(ec);
1963 
1964 	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1965 	    ec->reference_count >= 1)
1966 		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1967 
1968 	return 0;
1969 }
1970 
1971 static int acpi_ec_resume(struct device *dev)
1972 {
1973 	struct acpi_ec *ec =
1974 		acpi_driver_data(to_acpi_device(dev));
1975 
1976 	acpi_ec_enable_event(ec);
1977 	return 0;
1978 }
1979 #endif
1980 
1981 static const struct dev_pm_ops acpi_ec_pm = {
1982 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
1983 	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
1984 };
1985 
1986 static int param_set_event_clearing(const char *val,
1987 				    const struct kernel_param *kp)
1988 {
1989 	int result = 0;
1990 
1991 	if (!strncmp(val, "status", sizeof("status") - 1)) {
1992 		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1993 		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
1994 	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
1995 		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
1996 		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
1997 	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
1998 		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
1999 		pr_info("Assuming SCI_EVT clearing on event reads\n");
2000 	} else
2001 		result = -EINVAL;
2002 	return result;
2003 }
2004 
2005 static int param_get_event_clearing(char *buffer,
2006 				    const struct kernel_param *kp)
2007 {
2008 	switch (ec_event_clearing) {
2009 	case ACPI_EC_EVT_TIMING_STATUS:
2010 		return sprintf(buffer, "status");
2011 	case ACPI_EC_EVT_TIMING_QUERY:
2012 		return sprintf(buffer, "query");
2013 	case ACPI_EC_EVT_TIMING_EVENT:
2014 		return sprintf(buffer, "event");
2015 	default:
2016 		return sprintf(buffer, "invalid");
2017 	}
2018 	return 0;
2019 }
2020 
2021 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2022 		  NULL, 0644);
2023 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2024 
2025 static struct acpi_driver acpi_ec_driver = {
2026 	.name = "ec",
2027 	.class = ACPI_EC_CLASS,
2028 	.ids = ec_device_ids,
2029 	.ops = {
2030 		.add = acpi_ec_add,
2031 		.remove = acpi_ec_remove,
2032 		},
2033 	.drv.pm = &acpi_ec_pm,
2034 };
2035 
2036 static inline int acpi_ec_query_init(void)
2037 {
2038 	if (!ec_query_wq) {
2039 		ec_query_wq = alloc_workqueue("kec_query", 0,
2040 					      ec_max_queries);
2041 		if (!ec_query_wq)
2042 			return -ENODEV;
2043 	}
2044 	return 0;
2045 }
2046 
2047 static inline void acpi_ec_query_exit(void)
2048 {
2049 	if (ec_query_wq) {
2050 		destroy_workqueue(ec_query_wq);
2051 		ec_query_wq = NULL;
2052 	}
2053 }
2054 
2055 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2056 	{
2057 		.ident = "Thinkpad X1 Carbon 6th",
2058 		.matches = {
2059 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2060 			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2061 		},
2062 	},
2063 	{
2064 		.ident = "ThinkPad X1 Carbon 6th",
2065 		.matches = {
2066 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2067 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2068 		},
2069 	},
2070 	{
2071 		.ident = "ThinkPad X1 Yoga 3rd",
2072 		.matches = {
2073 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2074 			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2075 		},
2076 	},
2077 	{ },
2078 };
2079 
2080 int __init acpi_ec_init(void)
2081 {
2082 	int result;
2083 	int ecdt_fail, dsdt_fail;
2084 
2085 	/* register workqueue for _Qxx evaluations */
2086 	result = acpi_ec_query_init();
2087 	if (result)
2088 		return result;
2089 
2090 	/*
2091 	 * Disable EC wakeup on following systems to prevent periodic
2092 	 * wakeup from EC GPE.
2093 	 */
2094 	if (dmi_check_system(acpi_ec_no_wakeup)) {
2095 		ec_no_wakeup = true;
2096 		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2097 	}
2098 
2099 	/* Drivers must be started after acpi_ec_query_init() */
2100 	dsdt_fail = acpi_bus_register_driver(&acpi_ec_driver);
2101 	/*
2102 	 * Register ECDT to ACPI bus only when PNP0C09 probe fails. This is
2103 	 * useful for platforms (confirmed on ASUS X550ZE) with valid ECDT
2104 	 * settings but invalid DSDT settings.
2105 	 * https://bugzilla.kernel.org/show_bug.cgi?id=196847
2106 	 */
2107 	ecdt_fail = acpi_ec_ecdt_start();
2108 	return ecdt_fail && dsdt_fail ? -ENODEV : 0;
2109 }
2110 
2111 /* EC driver currently not unloadable */
2112 #if 0
2113 static void __exit acpi_ec_exit(void)
2114 {
2115 
2116 	acpi_bus_unregister_driver(&acpi_ec_driver);
2117 	acpi_ec_query_exit();
2118 }
2119 #endif	/* 0 */
2120