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 */
  78enum 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
  93enum {
  94	EC_FLAGS_QUERY_ENABLED,		/* Query is enabled */
  95	EC_FLAGS_EVENT_HANDLER_INSTALLED,	/* Event handler installed */
  96	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
  97	EC_FLAGS_EC_REG_CALLED,		/* OpReg ACPI _REG method called */
  98	EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
  99	EC_FLAGS_STARTED,		/* Driver is started */
 100	EC_FLAGS_STOPPED,		/* Driver is stopped */
 101	EC_FLAGS_EVENTS_MASKED,		/* Events masked */
 102};
 103
 104#define ACPI_EC_COMMAND_POLL		0x01 /* Available for command byte */
 105#define ACPI_EC_COMMAND_COMPLETE	0x02 /* Completed last byte */
 106
 107/* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 108static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 109module_param(ec_delay, uint, 0644);
 110MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 111
 112static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 113module_param(ec_max_queries, uint, 0644);
 114MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 115
 116static bool ec_busy_polling __read_mostly;
 117module_param(ec_busy_polling, bool, 0644);
 118MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 119
 120static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 121module_param(ec_polling_guard, uint, 0644);
 122MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 123
 124static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 125
 126/*
 127 * If the number of false interrupts per one transaction exceeds
 128 * this threshold, will think there is a GPE storm happened and
 129 * will disable the GPE for normal transaction.
 130 */
 131static unsigned int ec_storm_threshold  __read_mostly = 8;
 132module_param(ec_storm_threshold, uint, 0644);
 133MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 134
 135static bool ec_freeze_events __read_mostly;
 136module_param(ec_freeze_events, bool, 0644);
 137MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 138
 139static bool ec_no_wakeup __read_mostly;
 140module_param(ec_no_wakeup, bool, 0644);
 141MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 142
 143struct acpi_ec_query_handler {
 144	struct list_head node;
 145	acpi_ec_query_func func;
 146	acpi_handle handle;
 147	void *data;
 148	u8 query_bit;
 149	struct kref kref;
 150};
 151
 152struct transaction {
 153	const u8 *wdata;
 154	u8 *rdata;
 155	unsigned short irq_count;
 156	u8 command;
 157	u8 wi;
 158	u8 ri;
 159	u8 wlen;
 160	u8 rlen;
 161	u8 flags;
 162};
 163
 164struct acpi_ec_query {
 165	struct transaction transaction;
 166	struct work_struct work;
 167	struct acpi_ec_query_handler *handler;
 168	struct acpi_ec *ec;
 169};
 170
 171static int acpi_ec_submit_query(struct acpi_ec *ec);
 172static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 173static void acpi_ec_event_handler(struct work_struct *work);
 174
 175struct acpi_ec *first_ec;
 176EXPORT_SYMBOL(first_ec);
 177
 178static struct acpi_ec *boot_ec;
 179static bool boot_ec_is_ecdt;
 180static struct workqueue_struct *ec_wq;
 181static struct workqueue_struct *ec_query_wq;
 182
 183static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 184static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 185static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 186
 187/* --------------------------------------------------------------------------
 188 *                           Logging/Debugging
 189 * -------------------------------------------------------------------------- */
 190
 191/*
 192 * Splitters used by the developers to track the boundary of the EC
 193 * handling processes.
 194 */
 195#ifdef DEBUG
 196#define EC_DBG_SEP	" "
 197#define EC_DBG_DRV	"+++++"
 198#define EC_DBG_STM	"====="
 199#define EC_DBG_REQ	"*****"
 200#define EC_DBG_EVT	"#####"
 201#else
 202#define EC_DBG_SEP	""
 203#define EC_DBG_DRV
 204#define EC_DBG_STM
 205#define EC_DBG_REQ
 206#define EC_DBG_EVT
 207#endif
 208
 209#define ec_log_raw(fmt, ...) \
 210	pr_info(fmt "\n", ##__VA_ARGS__)
 211#define ec_dbg_raw(fmt, ...) \
 212	pr_debug(fmt "\n", ##__VA_ARGS__)
 213#define ec_log(filter, fmt, ...) \
 214	ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 215#define ec_dbg(filter, fmt, ...) \
 216	ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 217
 218#define ec_log_drv(fmt, ...) \
 219	ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 220#define ec_dbg_drv(fmt, ...) \
 221	ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 222#define ec_dbg_stm(fmt, ...) \
 223	ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 224#define ec_dbg_req(fmt, ...) \
 225	ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 226#define ec_dbg_evt(fmt, ...) \
 227	ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 228#define ec_dbg_ref(ec, fmt, ...) \
 229	ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 230
 231/* --------------------------------------------------------------------------
 232 *                           Device Flags
 233 * -------------------------------------------------------------------------- */
 234
 235static bool acpi_ec_started(struct acpi_ec *ec)
 236{
 237	return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 238	       !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 239}
 240
 241static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 242{
 243	/*
 244	 * There is an OSPM early stage logic. During the early stages
 245	 * (boot/resume), OSPMs shouldn't enable the event handling, only
 246	 * the EC transactions are allowed to be performed.
 247	 */
 248	if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 249		return false;
 250	/*
 251	 * However, disabling the event handling is experimental for late
 252	 * stage (suspend), and is controlled by the boot parameter of
 253	 * "ec_freeze_events":
 254	 * 1. true:  The EC event handling is disabled before entering
 255	 *           the noirq stage.
 256	 * 2. false: The EC event handling is automatically disabled as
 257	 *           soon as the EC driver is stopped.
 258	 */
 259	if (ec_freeze_events)
 260		return acpi_ec_started(ec);
 261	else
 262		return test_bit(EC_FLAGS_STARTED, &ec->flags);
 263}
 264
 265static bool acpi_ec_flushed(struct acpi_ec *ec)
 266{
 267	return ec->reference_count == 1;
 268}
 269
 270/* --------------------------------------------------------------------------
 271 *                           EC Registers
 272 * -------------------------------------------------------------------------- */
 273
 274static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 275{
 276	u8 x = inb(ec->command_addr);
 277
 278	ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 279		   "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 280		   x,
 281		   !!(x & ACPI_EC_FLAG_SCI),
 282		   !!(x & ACPI_EC_FLAG_BURST),
 283		   !!(x & ACPI_EC_FLAG_CMD),
 284		   !!(x & ACPI_EC_FLAG_IBF),
 285		   !!(x & ACPI_EC_FLAG_OBF));
 286	return x;
 287}
 288
 289static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 290{
 291	u8 x = inb(ec->data_addr);
 292
 293	ec->timestamp = jiffies;
 294	ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 295	return x;
 296}
 297
 298static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 299{
 300	ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 301	outb(command, ec->command_addr);
 302	ec->timestamp = jiffies;
 303}
 304
 305static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 306{
 307	ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 308	outb(data, ec->data_addr);
 309	ec->timestamp = jiffies;
 310}
 311
 312#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 313static const char *acpi_ec_cmd_string(u8 cmd)
 314{
 315	switch (cmd) {
 316	case 0x80:
 317		return "RD_EC";
 318	case 0x81:
 319		return "WR_EC";
 320	case 0x82:
 321		return "BE_EC";
 322	case 0x83:
 323		return "BD_EC";
 324	case 0x84:
 325		return "QR_EC";
 326	}
 327	return "UNKNOWN";
 328}
 329#else
 330#define acpi_ec_cmd_string(cmd)		"UNDEF"
 331#endif
 332
 333/* --------------------------------------------------------------------------
 334 *                           GPE Registers
 335 * -------------------------------------------------------------------------- */
 336
 337static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 338{
 339	acpi_event_status gpe_status = 0;
 340
 341	(void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 342	return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 343}
 344
 345static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 346{
 347	if (open)
 348		acpi_enable_gpe(NULL, ec->gpe);
 349	else {
 350		BUG_ON(ec->reference_count < 1);
 351		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 352	}
 353	if (acpi_ec_gpe_status_set(ec)) {
 354		/*
 355		 * On some platforms, EN=1 writes cannot trigger GPE. So
 356		 * software need to manually trigger a pseudo GPE event on
 357		 * EN=1 writes.
 358		 */
 359		ec_dbg_raw("Polling quirk");
 360		advance_transaction(ec, false);
 361	}
 362}
 363
 364static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 365{
 366	if (close)
 367		acpi_disable_gpe(NULL, ec->gpe);
 368	else {
 369		BUG_ON(ec->reference_count < 1);
 370		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 371	}
 372}
 373
 374/* --------------------------------------------------------------------------
 375 *                           Transaction Management
 376 * -------------------------------------------------------------------------- */
 377
 378static void acpi_ec_submit_request(struct acpi_ec *ec)
 379{
 380	ec->reference_count++;
 381	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 382	    ec->gpe >= 0 && ec->reference_count == 1)
 383		acpi_ec_enable_gpe(ec, true);
 384}
 385
 386static void acpi_ec_complete_request(struct acpi_ec *ec)
 387{
 388	bool flushed = false;
 389
 390	ec->reference_count--;
 391	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 392	    ec->gpe >= 0 && ec->reference_count == 0)
 393		acpi_ec_disable_gpe(ec, true);
 394	flushed = acpi_ec_flushed(ec);
 395	if (flushed)
 396		wake_up(&ec->wait);
 397}
 398
 399static void acpi_ec_mask_events(struct acpi_ec *ec)
 400{
 401	if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 402		if (ec->gpe >= 0)
 403			acpi_ec_disable_gpe(ec, false);
 404		else
 405			disable_irq_nosync(ec->irq);
 406
 407		ec_dbg_drv("Polling enabled");
 408		set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 409	}
 410}
 411
 412static void acpi_ec_unmask_events(struct acpi_ec *ec)
 413{
 414	if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 415		clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 416		if (ec->gpe >= 0)
 417			acpi_ec_enable_gpe(ec, false);
 418		else
 419			enable_irq(ec->irq);
 420
 421		ec_dbg_drv("Polling disabled");
 422	}
 423}
 424
 425/*
 426 * acpi_ec_submit_flushable_request() - Increase the reference count unless
 427 *                                      the flush operation is not in
 428 *                                      progress
 429 * @ec: the EC device
 430 *
 431 * This function must be used before taking a new action that should hold
 432 * the reference count.  If this function returns false, then the action
 433 * must be discarded or it will prevent the flush operation from being
 434 * completed.
 435 */
 436static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 437{
 438	if (!acpi_ec_started(ec))
 439		return false;
 440	acpi_ec_submit_request(ec);
 441	return true;
 442}
 443
 444static void acpi_ec_submit_event(struct acpi_ec *ec)
 445{
 446	/*
 447	 * It is safe to mask the events here, because acpi_ec_close_event()
 448	 * will run at least once after this.
 449	 */
 450	acpi_ec_mask_events(ec);
 451	if (!acpi_ec_event_enabled(ec))
 452		return;
 453
 454	if (ec->event_state != EC_EVENT_READY)
 455		return;
 456
 457	ec_dbg_evt("Command(%s) submitted/blocked",
 458		   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 459
 460	ec->event_state = EC_EVENT_IN_PROGRESS;
 461	/*
 462	 * If events_to_process is greater than 0 at this point, the while ()
 463	 * loop in acpi_ec_event_handler() is still running and incrementing
 464	 * events_to_process will cause it to invoke acpi_ec_submit_query() once
 465	 * more, so it is not necessary to queue up the event work to start the
 466	 * same loop again.
 467	 */
 468	if (ec->events_to_process++ > 0)
 469		return;
 470
 471	ec->events_in_progress++;
 472	queue_work(ec_wq, &ec->work);
 473}
 474
 475static void acpi_ec_complete_event(struct acpi_ec *ec)
 476{
 477	if (ec->event_state == EC_EVENT_IN_PROGRESS)
 478		ec->event_state = EC_EVENT_COMPLETE;
 479}
 480
 481static void acpi_ec_close_event(struct acpi_ec *ec)
 482{
 483	if (ec->event_state != EC_EVENT_READY)
 484		ec_dbg_evt("Command(%s) unblocked",
 485			   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 486
 487	ec->event_state = EC_EVENT_READY;
 488	acpi_ec_unmask_events(ec);
 489}
 490
 491static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 492{
 493	if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 494		ec_log_drv("event unblocked");
 495	/*
 496	 * Unconditionally invoke this once after enabling the event
 497	 * handling mechanism to detect the pending events.
 498	 */
 499	advance_transaction(ec, false);
 500}
 501
 502static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 503{
 504	if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 505		ec_log_drv("event blocked");
 506}
 507
 508/*
 509 * Process _Q events that might have accumulated in the EC.
 510 * Run with locked ec mutex.
 511 */
 512static void acpi_ec_clear(struct acpi_ec *ec)
 513{
 514	int i;
 515
 516	for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 517		if (acpi_ec_submit_query(ec))
 518			break;
 519	}
 520	if (unlikely(i == ACPI_EC_CLEAR_MAX))
 521		pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 522	else
 523		pr_info("%d stale EC events cleared\n", i);
 524}
 525
 526static void acpi_ec_enable_event(struct acpi_ec *ec)
 527{
 528	unsigned long flags;
 529
 530	spin_lock_irqsave(&ec->lock, flags);
 531	if (acpi_ec_started(ec))
 532		__acpi_ec_enable_event(ec);
 533	spin_unlock_irqrestore(&ec->lock, flags);
 534
 535	/* Drain additional events if hardware requires that */
 536	if (EC_FLAGS_CLEAR_ON_RESUME)
 537		acpi_ec_clear(ec);
 538}
 539
 540#ifdef CONFIG_PM_SLEEP
 541static void __acpi_ec_flush_work(void)
 542{
 543	flush_workqueue(ec_wq); /* flush ec->work */
 544	flush_workqueue(ec_query_wq); /* flush queries */
 545}
 546
 547static void acpi_ec_disable_event(struct acpi_ec *ec)
 548{
 549	unsigned long flags;
 550
 551	spin_lock_irqsave(&ec->lock, flags);
 552	__acpi_ec_disable_event(ec);
 553	spin_unlock_irqrestore(&ec->lock, flags);
 554
 555	/*
 556	 * When ec_freeze_events is true, we need to flush events in
 557	 * the proper position before entering the noirq stage.
 558	 */
 559	__acpi_ec_flush_work();
 560}
 561
 562void acpi_ec_flush_work(void)
 563{
 564	/* Without ec_wq there is nothing to flush. */
 565	if (!ec_wq)
 566		return;
 567
 568	__acpi_ec_flush_work();
 569}
 570#endif /* CONFIG_PM_SLEEP */
 571
 572static bool acpi_ec_guard_event(struct acpi_ec *ec)
 573{
 574	unsigned long flags;
 575	bool guarded;
 576
 577	spin_lock_irqsave(&ec->lock, flags);
 578	/*
 579	 * If firmware SCI_EVT clearing timing is "event", we actually
 580	 * don't know when the SCI_EVT will be cleared by firmware after
 581	 * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 582	 * acceptable period.
 583	 *
 584	 * The guarding period is applicable if the event state is not
 585	 * EC_EVENT_READY, but otherwise if the current transaction is of the
 586	 * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
 587	 * and it should not be applied to let the transaction transition into
 588	 * the ACPI_EC_COMMAND_POLL state immediately.
 589	 */
 590	guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 591		ec->event_state != EC_EVENT_READY &&
 592		(!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
 593	spin_unlock_irqrestore(&ec->lock, flags);
 594	return guarded;
 595}
 596
 597static 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
 609static 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
 621static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 622{
 623	ec->curr->flags |= flag;
 624
 625	if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
 626		return;
 627
 628	switch (ec_event_clearing) {
 629	case ACPI_EC_EVT_TIMING_STATUS:
 630		if (flag == ACPI_EC_COMMAND_POLL)
 631			acpi_ec_close_event(ec);
 632
 633		return;
 634
 635	case ACPI_EC_EVT_TIMING_QUERY:
 636		if (flag == ACPI_EC_COMMAND_COMPLETE)
 637			acpi_ec_close_event(ec);
 638
 639		return;
 640
 641	case ACPI_EC_EVT_TIMING_EVENT:
 642		if (flag == ACPI_EC_COMMAND_COMPLETE)
 643			acpi_ec_complete_event(ec);
 644	}
 645}
 646
 647static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 648{
 649	if (t->irq_count < ec_storm_threshold)
 650		++t->irq_count;
 651
 652	/* Trigger if the threshold is 0 too. */
 653	if (t->irq_count == ec_storm_threshold)
 654		acpi_ec_mask_events(ec);
 655}
 656
 657static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 658{
 659	struct transaction *t = ec->curr;
 660	bool wakeup = false;
 661	u8 status;
 662
 663	ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 664
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 665	status = acpi_ec_read_status(ec);
 666
 667	/*
 668	 * Another IRQ or a guarded polling mode advancement is detected,
 669	 * the next QR_EC submission is then allowed.
 670	 */
 671	if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 672		if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 673		    ec->event_state == EC_EVENT_COMPLETE)
 674			acpi_ec_close_event(ec);
 675
 676		if (!t)
 677			goto out;
 678	}
 679
 680	if (t->flags & ACPI_EC_COMMAND_POLL) {
 681		if (t->wlen > t->wi) {
 682			if (!(status & ACPI_EC_FLAG_IBF))
 683				acpi_ec_write_data(ec, t->wdata[t->wi++]);
 684			else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 685				acpi_ec_spurious_interrupt(ec, t);
 686		} else if (t->rlen > t->ri) {
 687			if (status & ACPI_EC_FLAG_OBF) {
 688				t->rdata[t->ri++] = acpi_ec_read_data(ec);
 689				if (t->rlen == t->ri) {
 690					ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 691					wakeup = true;
 692					if (t->command == ACPI_EC_COMMAND_QUERY)
 693						ec_dbg_evt("Command(%s) completed by hardware",
 694							   acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 695				}
 696			} else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 697				acpi_ec_spurious_interrupt(ec, t);
 698			}
 699		} else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 700			ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 701			wakeup = true;
 702		}
 703	} else if (!(status & ACPI_EC_FLAG_IBF)) {
 704		acpi_ec_write_cmd(ec, t->command);
 705		ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 706	}
 707
 708out:
 709	if (status & ACPI_EC_FLAG_SCI)
 710		acpi_ec_submit_event(ec);
 711
 712	if (wakeup && interrupt)
 713		wake_up(&ec->wait);
 714}
 715
 716static void start_transaction(struct acpi_ec *ec)
 717{
 718	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 719	ec->curr->flags = 0;
 720}
 721
 722static int ec_guard(struct acpi_ec *ec)
 723{
 724	unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 725	unsigned long timeout = ec->timestamp + guard;
 726
 727	/* Ensure guarding period before polling EC status */
 728	do {
 729		if (ec->busy_polling) {
 730			/* Perform busy polling */
 731			if (ec_transaction_completed(ec))
 732				return 0;
 733			udelay(jiffies_to_usecs(guard));
 734		} else {
 735			/*
 736			 * Perform wait polling
 737			 * 1. Wait the transaction to be completed by the
 738			 *    GPE handler after the transaction enters
 739			 *    ACPI_EC_COMMAND_POLL state.
 740			 * 2. A special guarding logic is also required
 741			 *    for event clearing mode "event" before the
 742			 *    transaction enters ACPI_EC_COMMAND_POLL
 743			 *    state.
 744			 */
 745			if (!ec_transaction_polled(ec) &&
 746			    !acpi_ec_guard_event(ec))
 747				break;
 748			if (wait_event_timeout(ec->wait,
 749					       ec_transaction_completed(ec),
 750					       guard))
 751				return 0;
 752		}
 753	} while (time_before(jiffies, timeout));
 754	return -ETIME;
 755}
 756
 757static int ec_poll(struct acpi_ec *ec)
 758{
 759	unsigned long flags;
 760	int repeat = 5; /* number of command restarts */
 761
 762	while (repeat--) {
 763		unsigned long delay = jiffies +
 764			msecs_to_jiffies(ec_delay);
 765		do {
 766			if (!ec_guard(ec))
 767				return 0;
 768			spin_lock_irqsave(&ec->lock, flags);
 769			advance_transaction(ec, false);
 770			spin_unlock_irqrestore(&ec->lock, flags);
 771		} while (time_before(jiffies, delay));
 772		pr_debug("controller reset, restart transaction\n");
 773		spin_lock_irqsave(&ec->lock, flags);
 774		start_transaction(ec);
 775		spin_unlock_irqrestore(&ec->lock, flags);
 776	}
 777	return -ETIME;
 778}
 779
 780static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 781					struct transaction *t)
 782{
 783	unsigned long tmp;
 784	int ret = 0;
 785
 786	/* start transaction */
 787	spin_lock_irqsave(&ec->lock, tmp);
 788	/* Enable GPE for command processing (IBF=0/OBF=1) */
 789	if (!acpi_ec_submit_flushable_request(ec)) {
 790		ret = -EINVAL;
 791		goto unlock;
 792	}
 793	ec_dbg_ref(ec, "Increase command");
 794	/* following two actions should be kept atomic */
 795	ec->curr = t;
 796	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 797	start_transaction(ec);
 798	spin_unlock_irqrestore(&ec->lock, tmp);
 799
 800	ret = ec_poll(ec);
 801
 802	spin_lock_irqsave(&ec->lock, tmp);
 803	if (t->irq_count == ec_storm_threshold)
 804		acpi_ec_unmask_events(ec);
 805	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 806	ec->curr = NULL;
 807	/* Disable GPE for command processing (IBF=0/OBF=1) */
 808	acpi_ec_complete_request(ec);
 809	ec_dbg_ref(ec, "Decrease command");
 810unlock:
 811	spin_unlock_irqrestore(&ec->lock, tmp);
 812	return ret;
 813}
 814
 815static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 816{
 817	int status;
 818	u32 glk;
 819
 820	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 821		return -EINVAL;
 822	if (t->rdata)
 823		memset(t->rdata, 0, t->rlen);
 824
 825	mutex_lock(&ec->mutex);
 826	if (ec->global_lock) {
 827		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 828		if (ACPI_FAILURE(status)) {
 829			status = -ENODEV;
 830			goto unlock;
 831		}
 832	}
 833
 834	status = acpi_ec_transaction_unlocked(ec, t);
 835
 836	if (ec->global_lock)
 837		acpi_release_global_lock(glk);
 838unlock:
 839	mutex_unlock(&ec->mutex);
 840	return status;
 841}
 842
 843static int acpi_ec_burst_enable(struct acpi_ec *ec)
 844{
 845	u8 d;
 846	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 847				.wdata = NULL, .rdata = &d,
 848				.wlen = 0, .rlen = 1};
 849
 850	return acpi_ec_transaction(ec, &t);
 851}
 852
 853static int acpi_ec_burst_disable(struct acpi_ec *ec)
 854{
 855	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 856				.wdata = NULL, .rdata = NULL,
 857				.wlen = 0, .rlen = 0};
 858
 859	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 860				acpi_ec_transaction(ec, &t) : 0;
 861}
 862
 863static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 864{
 865	int result;
 866	u8 d;
 867	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 868				.wdata = &address, .rdata = &d,
 869				.wlen = 1, .rlen = 1};
 870
 871	result = acpi_ec_transaction(ec, &t);
 872	*data = d;
 873	return result;
 874}
 875
 876static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 877{
 878	u8 wdata[2] = { address, data };
 879	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 880				.wdata = wdata, .rdata = NULL,
 881				.wlen = 2, .rlen = 0};
 882
 883	return acpi_ec_transaction(ec, &t);
 884}
 885
 886int ec_read(u8 addr, u8 *val)
 887{
 888	int err;
 889	u8 temp_data;
 890
 891	if (!first_ec)
 892		return -ENODEV;
 893
 894	err = acpi_ec_read(first_ec, addr, &temp_data);
 895
 896	if (!err) {
 897		*val = temp_data;
 898		return 0;
 899	}
 900	return err;
 901}
 902EXPORT_SYMBOL(ec_read);
 903
 904int ec_write(u8 addr, u8 val)
 905{
 906	if (!first_ec)
 907		return -ENODEV;
 908
 909	return acpi_ec_write(first_ec, addr, val);
 910}
 911EXPORT_SYMBOL(ec_write);
 912
 913int ec_transaction(u8 command,
 914		   const u8 *wdata, unsigned wdata_len,
 915		   u8 *rdata, unsigned rdata_len)
 916{
 917	struct transaction t = {.command = command,
 918				.wdata = wdata, .rdata = rdata,
 919				.wlen = wdata_len, .rlen = rdata_len};
 920
 921	if (!first_ec)
 922		return -ENODEV;
 923
 924	return acpi_ec_transaction(first_ec, &t);
 925}
 926EXPORT_SYMBOL(ec_transaction);
 927
 928/* Get the handle to the EC device */
 929acpi_handle ec_get_handle(void)
 930{
 931	if (!first_ec)
 932		return NULL;
 933	return first_ec->handle;
 934}
 935EXPORT_SYMBOL(ec_get_handle);
 936
 937static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 938{
 939	unsigned long flags;
 940
 941	spin_lock_irqsave(&ec->lock, flags);
 942	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 943		ec_dbg_drv("Starting EC");
 944		/* Enable GPE for event processing (SCI_EVT=1) */
 945		if (!resuming) {
 946			acpi_ec_submit_request(ec);
 947			ec_dbg_ref(ec, "Increase driver");
 948		}
 949		ec_log_drv("EC started");
 950	}
 951	spin_unlock_irqrestore(&ec->lock, flags);
 952}
 953
 954static bool acpi_ec_stopped(struct acpi_ec *ec)
 955{
 956	unsigned long flags;
 957	bool flushed;
 958
 959	spin_lock_irqsave(&ec->lock, flags);
 960	flushed = acpi_ec_flushed(ec);
 961	spin_unlock_irqrestore(&ec->lock, flags);
 962	return flushed;
 963}
 964
 965static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 966{
 967	unsigned long flags;
 968
 969	spin_lock_irqsave(&ec->lock, flags);
 970	if (acpi_ec_started(ec)) {
 971		ec_dbg_drv("Stopping EC");
 972		set_bit(EC_FLAGS_STOPPED, &ec->flags);
 973		spin_unlock_irqrestore(&ec->lock, flags);
 974		wait_event(ec->wait, acpi_ec_stopped(ec));
 975		spin_lock_irqsave(&ec->lock, flags);
 976		/* Disable GPE for event processing (SCI_EVT=1) */
 977		if (!suspending) {
 978			acpi_ec_complete_request(ec);
 979			ec_dbg_ref(ec, "Decrease driver");
 980		} else if (!ec_freeze_events)
 981			__acpi_ec_disable_event(ec);
 982		clear_bit(EC_FLAGS_STARTED, &ec->flags);
 983		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 984		ec_log_drv("EC stopped");
 985	}
 986	spin_unlock_irqrestore(&ec->lock, flags);
 987}
 988
 989static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 990{
 991	unsigned long flags;
 992
 993	spin_lock_irqsave(&ec->lock, flags);
 994	ec->busy_polling = true;
 995	ec->polling_guard = 0;
 996	ec_log_drv("interrupt blocked");
 997	spin_unlock_irqrestore(&ec->lock, flags);
 998}
 999
1000static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1001{
1002	unsigned long flags;
1003
1004	spin_lock_irqsave(&ec->lock, flags);
1005	ec->busy_polling = ec_busy_polling;
1006	ec->polling_guard = ec_polling_guard;
1007	ec_log_drv("interrupt unblocked");
1008	spin_unlock_irqrestore(&ec->lock, flags);
1009}
1010
1011void acpi_ec_block_transactions(void)
1012{
1013	struct acpi_ec *ec = first_ec;
1014
1015	if (!ec)
1016		return;
1017
1018	mutex_lock(&ec->mutex);
1019	/* Prevent transactions from being carried out */
1020	acpi_ec_stop(ec, true);
1021	mutex_unlock(&ec->mutex);
1022}
1023
1024void acpi_ec_unblock_transactions(void)
1025{
1026	/*
1027	 * Allow transactions to happen again (this function is called from
1028	 * atomic context during wakeup, so we don't need to acquire the mutex).
1029	 */
1030	if (first_ec)
1031		acpi_ec_start(first_ec, true);
1032}
1033
1034/* --------------------------------------------------------------------------
1035                                Event Management
1036   -------------------------------------------------------------------------- */
1037static struct acpi_ec_query_handler *
1038acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1039{
1040	struct acpi_ec_query_handler *handler;
1041
1042	mutex_lock(&ec->mutex);
1043	list_for_each_entry(handler, &ec->list, node) {
1044		if (value == handler->query_bit) {
1045			kref_get(&handler->kref);
1046			mutex_unlock(&ec->mutex);
1047			return handler;
1048		}
1049	}
1050	mutex_unlock(&ec->mutex);
1051	return NULL;
1052}
1053
1054static void acpi_ec_query_handler_release(struct kref *kref)
1055{
1056	struct acpi_ec_query_handler *handler =
1057		container_of(kref, struct acpi_ec_query_handler, kref);
1058
1059	kfree(handler);
1060}
1061
1062static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1063{
1064	kref_put(&handler->kref, acpi_ec_query_handler_release);
1065}
1066
1067int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1068			      acpi_handle handle, acpi_ec_query_func func,
1069			      void *data)
1070{
1071	struct acpi_ec_query_handler *handler;
1072
1073	if (!handle && !func)
1074		return -EINVAL;
1075
1076	handler = kzalloc(sizeof(*handler), GFP_KERNEL);
1077	if (!handler)
1078		return -ENOMEM;
1079
1080	handler->query_bit = query_bit;
1081	handler->handle = handle;
1082	handler->func = func;
1083	handler->data = data;
1084	mutex_lock(&ec->mutex);
1085	kref_init(&handler->kref);
1086	list_add(&handler->node, &ec->list);
1087	mutex_unlock(&ec->mutex);
1088
1089	return 0;
1090}
1091EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1092
1093static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1094					  bool remove_all, u8 query_bit)
1095{
1096	struct acpi_ec_query_handler *handler, *tmp;
1097	LIST_HEAD(free_list);
1098
1099	mutex_lock(&ec->mutex);
1100	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1101		/*
1102		 * When remove_all is false, only remove custom query handlers
1103		 * which have handler->func set. This is done to preserve query
1104		 * handlers discovered thru ACPI, as they should continue handling
1105		 * EC queries.
1106		 */
1107		if (remove_all || (handler->func && handler->query_bit == query_bit)) {
1108			list_del_init(&handler->node);
1109			list_add(&handler->node, &free_list);
1110
1111		}
1112	}
1113	mutex_unlock(&ec->mutex);
1114	list_for_each_entry_safe(handler, tmp, &free_list, node)
1115		acpi_ec_put_query_handler(handler);
1116}
1117
1118void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1119{
1120	acpi_ec_remove_query_handlers(ec, false, query_bit);
1121	flush_workqueue(ec_query_wq);
1122}
1123EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1124
1125static void acpi_ec_event_processor(struct work_struct *work)
1126{
1127	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1128	struct acpi_ec_query_handler *handler = q->handler;
1129	struct acpi_ec *ec = q->ec;
1130
1131	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1132
1133	if (handler->func)
1134		handler->func(handler->data);
1135	else if (handler->handle)
1136		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1137
1138	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1139
1140	spin_lock_irq(&ec->lock);
1141	ec->queries_in_progress--;
1142	spin_unlock_irq(&ec->lock);
1143
1144	acpi_ec_put_query_handler(handler);
1145	kfree(q);
1146}
1147
1148static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1149{
1150	struct acpi_ec_query *q;
1151	struct transaction *t;
1152
1153	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1154	if (!q)
1155		return NULL;
1156
1157	INIT_WORK(&q->work, acpi_ec_event_processor);
1158	t = &q->transaction;
1159	t->command = ACPI_EC_COMMAND_QUERY;
1160	t->rdata = pval;
1161	t->rlen = 1;
1162	q->ec = ec;
1163	return q;
1164}
1165
1166static int acpi_ec_submit_query(struct acpi_ec *ec)
1167{
1168	struct acpi_ec_query *q;
1169	u8 value = 0;
1170	int result;
1171
1172	q = acpi_ec_create_query(ec, &value);
1173	if (!q)
1174		return -ENOMEM;
1175
1176	/*
1177	 * Query the EC to find out which _Qxx method we need to evaluate.
1178	 * Note that successful completion of the query causes the ACPI_EC_SCI
1179	 * bit to be cleared (and thus clearing the interrupt source).
1180	 */
1181	result = acpi_ec_transaction(ec, &q->transaction);
1182	if (result)
1183		goto err_exit;
1184
1185	if (!value) {
1186		result = -ENODATA;
1187		goto err_exit;
1188	}
1189
1190	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1191	if (!q->handler) {
1192		result = -ENODATA;
1193		goto err_exit;
1194	}
1195
1196	/*
1197	 * It is reported that _Qxx are evaluated in a parallel way on Windows:
1198	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1199	 *
1200	 * Put this log entry before queue_work() to make it appear in the log
1201	 * before any other messages emitted during workqueue handling.
1202	 */
1203	ec_dbg_evt("Query(0x%02x) scheduled", value);
1204
1205	spin_lock_irq(&ec->lock);
1206
1207	ec->queries_in_progress++;
1208	queue_work(ec_query_wq, &q->work);
1209
1210	spin_unlock_irq(&ec->lock);
1211
1212	return 0;
1213
1214err_exit:
1215	kfree(q);
1216
1217	return result;
1218}
1219
1220static void acpi_ec_event_handler(struct work_struct *work)
1221{
1222	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1223
1224	ec_dbg_evt("Event started");
1225
1226	spin_lock_irq(&ec->lock);
1227
1228	while (ec->events_to_process) {
1229		spin_unlock_irq(&ec->lock);
1230
1231		acpi_ec_submit_query(ec);
1232
1233		spin_lock_irq(&ec->lock);
1234
1235		ec->events_to_process--;
1236	}
1237
1238	/*
1239	 * Before exit, make sure that the it will be possible to queue up the
1240	 * event handling work again regardless of whether or not the query
1241	 * queued up above is processed successfully.
1242	 */
1243	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1244		bool guard_timeout;
1245
1246		acpi_ec_complete_event(ec);
1247
1248		ec_dbg_evt("Event stopped");
1249
1250		spin_unlock_irq(&ec->lock);
1251
1252		guard_timeout = !!ec_guard(ec);
1253
1254		spin_lock_irq(&ec->lock);
1255
1256		/* Take care of SCI_EVT unless someone else is doing that. */
1257		if (guard_timeout && !ec->curr)
1258			advance_transaction(ec, false);
1259	} else {
1260		acpi_ec_close_event(ec);
1261
1262		ec_dbg_evt("Event stopped");
1263	}
1264
1265	ec->events_in_progress--;
1266
1267	spin_unlock_irq(&ec->lock);
1268}
1269
1270static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
1271{
1272	/*
1273	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
1274	 * changes to always trigger a GPE interrupt.
1275	 *
1276	 * GPE STS is a W1C register, which means:
1277	 *
1278	 * 1. Software can clear it without worrying about clearing the other
1279	 *    GPEs' STS bits when the hardware sets them in parallel.
1280	 *
1281	 * 2. As long as software can ensure only clearing it when it is set,
1282	 *    hardware won't set it in parallel.
1283	 */
1284	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
1285		acpi_clear_gpe(NULL, ec->gpe);
1286
1287	advance_transaction(ec, true);
1288}
1289
1290static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1291{
1292	unsigned long flags;
1293
1294	spin_lock_irqsave(&ec->lock, flags);
1295
1296	clear_gpe_and_advance_transaction(ec, true);
1297
1298	spin_unlock_irqrestore(&ec->lock, flags);
1299}
1300
1301static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1302			       u32 gpe_number, void *data)
1303{
1304	acpi_ec_handle_interrupt(data);
1305	return ACPI_INTERRUPT_HANDLED;
1306}
1307
1308static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1309{
1310	acpi_ec_handle_interrupt(data);
1311	return IRQ_HANDLED;
1312}
1313
1314/* --------------------------------------------------------------------------
1315 *                           Address Space Management
1316 * -------------------------------------------------------------------------- */
1317
1318static acpi_status
1319acpi_ec_space_handler(u32 function, acpi_physical_address address,
1320		      u32 bits, u64 *value64,
1321		      void *handler_context, void *region_context)
1322{
1323	struct acpi_ec *ec = handler_context;
1324	int result = 0, i, bytes = bits / 8;
1325	u8 *value = (u8 *)value64;
1326
1327	if ((address > 0xFF) || !value || !handler_context)
1328		return AE_BAD_PARAMETER;
1329
1330	if (function != ACPI_READ && function != ACPI_WRITE)
1331		return AE_BAD_PARAMETER;
1332
1333	if (ec->busy_polling || bits > 8)
1334		acpi_ec_burst_enable(ec);
1335
1336	for (i = 0; i < bytes; ++i, ++address, ++value)
1337		result = (function == ACPI_READ) ?
1338			acpi_ec_read(ec, address, value) :
1339			acpi_ec_write(ec, address, *value);
1340
1341	if (ec->busy_polling || bits > 8)
1342		acpi_ec_burst_disable(ec);
1343
1344	switch (result) {
1345	case -EINVAL:
1346		return AE_BAD_PARAMETER;
1347	case -ENODEV:
1348		return AE_NOT_FOUND;
1349	case -ETIME:
1350		return AE_TIME;
1351	default:
1352		return AE_OK;
1353	}
1354}
1355
1356/* --------------------------------------------------------------------------
1357 *                             Driver Interface
1358 * -------------------------------------------------------------------------- */
1359
1360static acpi_status
1361ec_parse_io_ports(struct acpi_resource *resource, void *context);
1362
1363static void acpi_ec_free(struct acpi_ec *ec)
1364{
1365	if (first_ec == ec)
1366		first_ec = NULL;
1367	if (boot_ec == ec)
1368		boot_ec = NULL;
1369	kfree(ec);
1370}
1371
1372static struct acpi_ec *acpi_ec_alloc(void)
1373{
1374	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1375
1376	if (!ec)
1377		return NULL;
1378	mutex_init(&ec->mutex);
1379	init_waitqueue_head(&ec->wait);
1380	INIT_LIST_HEAD(&ec->list);
1381	spin_lock_init(&ec->lock);
1382	INIT_WORK(&ec->work, acpi_ec_event_handler);
1383	ec->timestamp = jiffies;
1384	ec->busy_polling = true;
1385	ec->polling_guard = 0;
1386	ec->gpe = -1;
1387	ec->irq = -1;
1388	return ec;
1389}
1390
1391static acpi_status
1392acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1393			       void *context, void **return_value)
1394{
1395	char node_name[5];
1396	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1397	struct acpi_ec *ec = context;
1398	int value = 0;
1399	acpi_status status;
1400
1401	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1402
1403	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1404		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1405	return AE_OK;
1406}
1407
1408static acpi_status
1409ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1410{
1411	acpi_status status;
1412	unsigned long long tmp = 0;
1413	struct acpi_ec *ec = context;
1414
1415	/* clear addr values, ec_parse_io_ports depend on it */
1416	ec->command_addr = ec->data_addr = 0;
1417
1418	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1419				     ec_parse_io_ports, ec);
1420	if (ACPI_FAILURE(status))
1421		return status;
1422	if (ec->data_addr == 0 || ec->command_addr == 0)
1423		return AE_OK;
1424
1425	/* Get GPE bit assignment (EC events). */
1426	/* TODO: Add support for _GPE returning a package */
1427	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1428	if (ACPI_SUCCESS(status))
1429		ec->gpe = tmp;
1430	/*
1431	 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1432	 * platforms which use GpioInt instead of GPE.
1433	 */
1434
1435	/* Use the global lock for all EC transactions? */
1436	tmp = 0;
1437	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1438	ec->global_lock = tmp;
1439	ec->handle = handle;
1440	return AE_CTRL_TERMINATE;
1441}
1442
1443static bool install_gpe_event_handler(struct acpi_ec *ec)
1444{
1445	acpi_status status;
1446
1447	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1448					      ACPI_GPE_EDGE_TRIGGERED,
1449					      &acpi_ec_gpe_handler, ec);
1450	if (ACPI_FAILURE(status))
1451		return false;
1452
1453	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1454		acpi_ec_enable_gpe(ec, true);
1455
1456	return true;
1457}
1458
1459static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1460{
1461	return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
1462				    IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
1463}
1464
1465/**
1466 * ec_install_handlers - Install service callbacks and register query methods.
1467 * @ec: Target EC.
1468 * @device: ACPI device object corresponding to @ec.
1469 * @call_reg: If _REG should be called to notify OpRegion availability
1470 *
1471 * Install a handler for the EC address space type unless it has been installed
1472 * already.  If @device is not NULL, also look for EC query methods in the
1473 * namespace and register them, and install an event (either GPE or GPIO IRQ)
1474 * handler for the EC, if possible.
1475 *
1476 * Return:
1477 * -ENODEV if the address space handler cannot be installed, which means
1478 *  "unable to handle transactions",
1479 * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1480 * or 0 (success) otherwise.
1481 */
1482static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1483			       bool call_reg)
1484{
1485	acpi_status status;
1486
1487	acpi_ec_start(ec, false);
1488
1489	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1490		acpi_ec_enter_noirq(ec);
1491		status = acpi_install_address_space_handler_no_reg(ec->handle,
1492								   ACPI_ADR_SPACE_EC,
1493								   &acpi_ec_space_handler,
1494								   NULL, ec);
1495		if (ACPI_FAILURE(status)) {
1496			acpi_ec_stop(ec, false);
1497			return -ENODEV;
1498		}
1499		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1500		ec->address_space_handler_holder = ec->handle;
1501	}
1502
1503	if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1504		acpi_execute_reg_methods(ec->handle, ACPI_ADR_SPACE_EC);
1505		set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1506	}
1507
1508	if (!device)
1509		return 0;
1510
1511	if (ec->gpe < 0) {
1512		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1513		int irq = acpi_dev_gpio_irq_get(device, 0);
1514		/*
1515		 * Bail out right away for deferred probing or complete the
1516		 * initialization regardless of any other errors.
1517		 */
1518		if (irq == -EPROBE_DEFER)
1519			return -EPROBE_DEFER;
1520		else if (irq >= 0)
1521			ec->irq = irq;
1522	}
1523
1524	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1525		/* Find and register all query methods */
1526		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1527				    acpi_ec_register_query_methods,
1528				    NULL, ec, NULL);
1529		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1530	}
1531	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1532		bool ready = false;
1533
1534		if (ec->gpe >= 0)
1535			ready = install_gpe_event_handler(ec);
1536		else if (ec->irq >= 0)
1537			ready = install_gpio_irq_event_handler(ec);
1538
1539		if (ready) {
1540			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1541			acpi_ec_leave_noirq(ec);
1542		}
1543		/*
1544		 * Failures to install an event handler are not fatal, because
1545		 * the EC can be polled for events.
1546		 */
1547	}
1548	/* EC is fully operational, allow queries */
1549	acpi_ec_enable_event(ec);
1550
1551	return 0;
1552}
1553
1554static void ec_remove_handlers(struct acpi_ec *ec)
1555{
1556	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1557		if (ACPI_FAILURE(acpi_remove_address_space_handler(
1558					ec->address_space_handler_holder,
1559					ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1560			pr_err("failed to remove space handler\n");
1561		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1562	}
1563
1564	/*
1565	 * Stops handling the EC transactions after removing the operation
1566	 * region handler. This is required because _REG(DISCONNECT)
1567	 * invoked during the removal can result in new EC transactions.
1568	 *
1569	 * Flushes the EC requests and thus disables the GPE before
1570	 * removing the GPE handler. This is required by the current ACPICA
1571	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1572	 * it is indicated but there is no way to handle it. So the drivers
1573	 * must disable the GPEs prior to removing the GPE handlers.
1574	 */
1575	acpi_ec_stop(ec, false);
1576
1577	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1578		if (ec->gpe >= 0 &&
1579		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1580				 &acpi_ec_gpe_handler)))
1581			pr_err("failed to remove gpe handler\n");
1582
1583		if (ec->irq >= 0)
1584			free_irq(ec->irq, ec);
1585
1586		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1587	}
1588	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1589		acpi_ec_remove_query_handlers(ec, true, 0);
1590		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1591	}
1592}
1593
1594static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1595{
1596	int ret;
1597
1598	ret = ec_install_handlers(ec, device, call_reg);
1599	if (ret)
1600		return ret;
1601
1602	/* First EC capable of handling transactions */
1603	if (!first_ec)
1604		first_ec = ec;
1605
1606	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1607		ec->data_addr);
1608
1609	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1610		if (ec->gpe >= 0)
1611			pr_info("GPE=0x%x\n", ec->gpe);
1612		else
1613			pr_info("IRQ=%d\n", ec->irq);
1614	}
1615
1616	return ret;
1617}
1618
1619static int acpi_ec_add(struct acpi_device *device)
1620{
1621	struct acpi_ec *ec;
1622	int ret;
1623
1624	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1625	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1626
1627	if (boot_ec && (boot_ec->handle == device->handle ||
1628	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1629		/* Fast path: this device corresponds to the boot EC. */
1630		ec = boot_ec;
1631	} else {
1632		acpi_status status;
1633
1634		ec = acpi_ec_alloc();
1635		if (!ec)
1636			return -ENOMEM;
1637
1638		status = ec_parse_device(device->handle, 0, ec, NULL);
1639		if (status != AE_CTRL_TERMINATE) {
1640			ret = -EINVAL;
1641			goto err;
1642		}
1643
1644		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1645		    ec->data_addr == boot_ec->data_addr) {
1646			/*
1647			 * Trust PNP0C09 namespace location rather than ECDT ID.
1648			 * But trust ECDT GPE rather than _GPE because of ASUS
1649			 * quirks. So do not change boot_ec->gpe to ec->gpe,
1650			 * except when the TRUST_DSDT_GPE quirk is set.
1651			 */
1652			boot_ec->handle = ec->handle;
1653
1654			if (EC_FLAGS_TRUST_DSDT_GPE)
1655				boot_ec->gpe = ec->gpe;
1656
1657			acpi_handle_debug(ec->handle, "duplicated.\n");
1658			acpi_ec_free(ec);
1659			ec = boot_ec;
1660		}
1661	}
1662
1663	ret = acpi_ec_setup(ec, device, true);
1664	if (ret)
1665		goto err;
1666
1667	if (ec == boot_ec)
1668		acpi_handle_info(boot_ec->handle,
1669				 "Boot %s EC initialization complete\n",
1670				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1671
1672	acpi_handle_info(ec->handle,
1673			 "EC: Used to handle transactions and events\n");
1674
1675	device->driver_data = ec;
1676
1677	ret = !!request_region(ec->data_addr, 1, "EC data");
1678	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1679	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1680	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1681
1682	/* Reprobe devices depending on the EC */
1683	acpi_dev_clear_dependencies(device);
1684
1685	acpi_handle_debug(ec->handle, "enumerated.\n");
1686	return 0;
1687
1688err:
1689	if (ec != boot_ec)
1690		acpi_ec_free(ec);
1691
1692	return ret;
1693}
1694
1695static void acpi_ec_remove(struct acpi_device *device)
1696{
1697	struct acpi_ec *ec;
1698
1699	if (!device)
1700		return;
1701
1702	ec = acpi_driver_data(device);
1703	release_region(ec->data_addr, 1);
1704	release_region(ec->command_addr, 1);
1705	device->driver_data = NULL;
1706	if (ec != boot_ec) {
1707		ec_remove_handlers(ec);
1708		acpi_ec_free(ec);
1709	}
1710}
1711
1712static acpi_status
1713ec_parse_io_ports(struct acpi_resource *resource, void *context)
1714{
1715	struct acpi_ec *ec = context;
1716
1717	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1718		return AE_OK;
1719
1720	/*
1721	 * The first address region returned is the data port, and
1722	 * the second address region returned is the status/command
1723	 * port.
1724	 */
1725	if (ec->data_addr == 0)
1726		ec->data_addr = resource->data.io.minimum;
1727	else if (ec->command_addr == 0)
1728		ec->command_addr = resource->data.io.minimum;
1729	else
1730		return AE_CTRL_TERMINATE;
1731
1732	return AE_OK;
1733}
1734
1735static const struct acpi_device_id ec_device_ids[] = {
1736	{"PNP0C09", 0},
1737	{ACPI_ECDT_HID, 0},
1738	{"", 0},
1739};
1740
1741/*
1742 * This function is not Windows-compatible as Windows never enumerates the
1743 * namespace EC before the main ACPI device enumeration process. It is
1744 * retained for historical reason and will be deprecated in the future.
1745 */
1746void __init acpi_ec_dsdt_probe(void)
1747{
1748	struct acpi_ec *ec;
1749	acpi_status status;
1750	int ret;
1751
1752	/*
1753	 * If a platform has ECDT, there is no need to proceed as the
1754	 * following probe is not a part of the ACPI device enumeration,
1755	 * executing _STA is not safe, and thus this probe may risk of
1756	 * picking up an invalid EC device.
1757	 */
1758	if (boot_ec)
1759		return;
1760
1761	ec = acpi_ec_alloc();
1762	if (!ec)
1763		return;
1764
1765	/*
1766	 * At this point, the namespace is initialized, so start to find
1767	 * the namespace objects.
1768	 */
1769	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1770	if (ACPI_FAILURE(status) || !ec->handle) {
1771		acpi_ec_free(ec);
1772		return;
1773	}
1774
1775	/*
1776	 * When the DSDT EC is available, always re-configure boot EC to
1777	 * have _REG evaluated. _REG can only be evaluated after the
1778	 * namespace initialization.
1779	 * At this point, the GPE is not fully initialized, so do not to
1780	 * handle the events.
1781	 */
1782	ret = acpi_ec_setup(ec, NULL, true);
1783	if (ret) {
1784		acpi_ec_free(ec);
1785		return;
1786	}
1787
1788	boot_ec = ec;
1789
1790	acpi_handle_info(ec->handle,
1791			 "Boot DSDT EC used to handle transactions\n");
1792}
1793
1794/*
1795 * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1796 *
1797 * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1798 * found a matching object in the namespace.
1799 *
1800 * Next, in case the DSDT EC is not functioning, it is still necessary to
1801 * provide a functional ECDT EC to handle events, so add an extra device object
1802 * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1803 *
1804 * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1805 * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1806 */
1807static void __init acpi_ec_ecdt_start(void)
1808{
1809	struct acpi_table_ecdt *ecdt_ptr;
1810	acpi_handle handle;
1811	acpi_status status;
1812
1813	/* Bail out if a matching EC has been found in the namespace. */
1814	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1815		return;
1816
1817	/* Look up the object pointed to from the ECDT in the namespace. */
1818	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1819				(struct acpi_table_header **)&ecdt_ptr);
1820	if (ACPI_FAILURE(status))
1821		return;
1822
1823	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1824	if (ACPI_SUCCESS(status)) {
1825		boot_ec->handle = handle;
1826
1827		/* Add a special ACPI device object to represent the boot EC. */
1828		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1829	}
1830
1831	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1832}
1833
1834/*
1835 * On some hardware it is necessary to clear events accumulated by the EC during
1836 * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1837 * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1838 *
1839 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1840 *
1841 * Ideally, the EC should also be instructed NOT to accumulate events during
1842 * sleep (which Windows seems to do somehow), but the interface to control this
1843 * behaviour is not known at this time.
1844 *
1845 * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1846 * however it is very likely that other Samsung models are affected.
1847 *
1848 * On systems which don't accumulate _Q events during sleep, this extra check
1849 * should be harmless.
1850 */
1851static int ec_clear_on_resume(const struct dmi_system_id *id)
1852{
1853	pr_debug("Detected system needing EC poll on resume.\n");
1854	EC_FLAGS_CLEAR_ON_RESUME = 1;
1855	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1856	return 0;
1857}
1858
1859/*
1860 * Some ECDTs contain wrong register addresses.
1861 * MSI MS-171F
1862 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1863 */
1864static int ec_correct_ecdt(const struct dmi_system_id *id)
1865{
1866	pr_debug("Detected system needing ECDT address correction.\n");
1867	EC_FLAGS_CORRECT_ECDT = 1;
1868	return 0;
1869}
1870
1871/*
1872 * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1873 * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1874 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1875 */
1876static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1877{
1878	pr_debug("Detected system needing DSDT GPE setting.\n");
1879	EC_FLAGS_TRUST_DSDT_GPE = 1;
1880	return 0;
1881}
1882
1883static const struct dmi_system_id ec_dmi_table[] __initconst = {
1884	{
1885		/*
1886		 * MSI MS-171F
1887		 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1888		 */
1889		.callback = ec_correct_ecdt,
1890		.matches = {
1891			DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1892			DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1893		},
1894	},
1895	{
1896		/*
1897		 * HP Pavilion Gaming Laptop 15-cx0xxx
1898		 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1899		 */
1900		.callback = ec_honor_dsdt_gpe,
1901		.matches = {
1902			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1903			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1904		},
1905	},
1906	{
1907		/*
1908		 * HP Pavilion Gaming Laptop 15-cx0041ur
1909		 */
1910		.callback = ec_honor_dsdt_gpe,
1911		.matches = {
1912			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1913			DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1914		},
1915	},
1916	{
1917		/*
1918		 * HP Pavilion Gaming Laptop 15-dk1xxx
1919		 * https://github.com/systemd/systemd/issues/28942
1920		 */
1921		.callback = ec_honor_dsdt_gpe,
1922		.matches = {
1923			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1924			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
1925		},
1926	},
1927	{
1928		/*
1929		 * HP 250 G7 Notebook PC
1930		 */
1931		.callback = ec_honor_dsdt_gpe,
1932		.matches = {
1933			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1934			DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
1935		},
1936	},
1937	{
1938		/*
1939		 * Samsung hardware
1940		 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1941		 */
1942		.callback = ec_clear_on_resume,
1943		.matches = {
1944			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
1945		},
1946	},
1947	{}
1948};
1949
1950void __init acpi_ec_ecdt_probe(void)
1951{
1952	struct acpi_table_ecdt *ecdt_ptr;
1953	struct acpi_ec *ec;
1954	acpi_status status;
1955	int ret;
1956
1957	/* Generate a boot ec context. */
1958	dmi_check_system(ec_dmi_table);
1959	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1960				(struct acpi_table_header **)&ecdt_ptr);
1961	if (ACPI_FAILURE(status))
1962		return;
1963
1964	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1965		/*
1966		 * Asus X50GL:
1967		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1968		 */
1969		goto out;
1970	}
1971
1972	ec = acpi_ec_alloc();
1973	if (!ec)
1974		goto out;
1975
1976	if (EC_FLAGS_CORRECT_ECDT) {
1977		ec->command_addr = ecdt_ptr->data.address;
1978		ec->data_addr = ecdt_ptr->control.address;
1979	} else {
1980		ec->command_addr = ecdt_ptr->control.address;
1981		ec->data_addr = ecdt_ptr->data.address;
1982	}
1983
1984	/*
1985	 * Ignore the GPE value on Reduced Hardware platforms.
1986	 * Some products have this set to an erroneous value.
1987	 */
1988	if (!acpi_gbl_reduced_hardware)
1989		ec->gpe = ecdt_ptr->gpe;
1990
1991	ec->handle = ACPI_ROOT_OBJECT;
1992
1993	/*
1994	 * At this point, the namespace is not initialized, so do not find
1995	 * the namespace objects, or handle the events.
1996	 */
1997	ret = acpi_ec_setup(ec, NULL, false);
1998	if (ret) {
1999		acpi_ec_free(ec);
2000		goto out;
2001	}
2002
2003	boot_ec = ec;
2004	boot_ec_is_ecdt = true;
2005
2006	pr_info("Boot ECDT EC used to handle transactions\n");
2007
2008out:
2009	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2010}
2011
2012#ifdef CONFIG_PM_SLEEP
2013static int acpi_ec_suspend(struct device *dev)
2014{
2015	struct acpi_ec *ec =
2016		acpi_driver_data(to_acpi_device(dev));
2017
2018	if (!pm_suspend_no_platform() && ec_freeze_events)
2019		acpi_ec_disable_event(ec);
2020	return 0;
2021}
2022
2023static int acpi_ec_suspend_noirq(struct device *dev)
2024{
2025	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2026
2027	/*
2028	 * The SCI handler doesn't run at this point, so the GPE can be
2029	 * masked at the low level without side effects.
2030	 */
2031	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2032	    ec->gpe >= 0 && ec->reference_count >= 1)
2033		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2034
2035	acpi_ec_enter_noirq(ec);
2036
2037	return 0;
2038}
2039
2040static int acpi_ec_resume_noirq(struct device *dev)
2041{
2042	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2043
2044	acpi_ec_leave_noirq(ec);
2045
2046	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2047	    ec->gpe >= 0 && ec->reference_count >= 1)
2048		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2049
2050	return 0;
2051}
2052
2053static int acpi_ec_resume(struct device *dev)
2054{
2055	struct acpi_ec *ec =
2056		acpi_driver_data(to_acpi_device(dev));
2057
2058	acpi_ec_enable_event(ec);
2059	return 0;
2060}
2061
2062void acpi_ec_mark_gpe_for_wake(void)
2063{
2064	if (first_ec && !ec_no_wakeup)
2065		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2066}
2067EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2068
2069void acpi_ec_set_gpe_wake_mask(u8 action)
2070{
2071	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2072		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2073}
2074
2075static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2076{
2077	return ec->events_in_progress + ec->queries_in_progress > 0;
2078}
2079
2080bool acpi_ec_dispatch_gpe(void)
2081{
2082	bool work_in_progress = false;
2083
2084	if (!first_ec)
2085		return acpi_any_gpe_status_set(U32_MAX);
2086
2087	/*
2088	 * Report wakeup if the status bit is set for any enabled GPE other
2089	 * than the EC one.
2090	 */
2091	if (acpi_any_gpe_status_set(first_ec->gpe))
2092		return true;
2093
2094	/*
2095	 * Cancel the SCI wakeup and process all pending events in case there
2096	 * are any wakeup ones in there.
2097	 *
2098	 * Note that if any non-EC GPEs are active at this point, the SCI will
2099	 * retrigger after the rearming in acpi_s2idle_wake(), so no events
2100	 * should be missed by canceling the wakeup here.
2101	 */
2102	pm_system_cancel_wakeup();
2103
2104	/*
2105	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2106	 * to allow the caller to process events properly after that.
2107	 */
2108	spin_lock_irq(&first_ec->lock);
2109
2110	if (acpi_ec_gpe_status_set(first_ec)) {
2111		pm_pr_dbg("ACPI EC GPE status set\n");
2112
2113		clear_gpe_and_advance_transaction(first_ec, false);
2114		work_in_progress = acpi_ec_work_in_progress(first_ec);
2115	}
2116
2117	spin_unlock_irq(&first_ec->lock);
2118
2119	if (!work_in_progress)
2120		return false;
2121
2122	pm_pr_dbg("ACPI EC GPE dispatched\n");
2123
2124	/* Drain EC work. */
2125	do {
2126		acpi_ec_flush_work();
2127
2128		pm_pr_dbg("ACPI EC work flushed\n");
2129
2130		spin_lock_irq(&first_ec->lock);
2131
2132		work_in_progress = acpi_ec_work_in_progress(first_ec);
2133
2134		spin_unlock_irq(&first_ec->lock);
2135	} while (work_in_progress && !pm_wakeup_pending());
2136
2137	return false;
2138}
2139#endif /* CONFIG_PM_SLEEP */
2140
2141static const struct dev_pm_ops acpi_ec_pm = {
2142	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2143	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2144};
2145
2146static int param_set_event_clearing(const char *val,
2147				    const struct kernel_param *kp)
2148{
2149	int result = 0;
2150
2151	if (!strncmp(val, "status", sizeof("status") - 1)) {
2152		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2153		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2154	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2155		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2156		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2157	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2158		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2159		pr_info("Assuming SCI_EVT clearing on event reads\n");
2160	} else
2161		result = -EINVAL;
2162	return result;
2163}
2164
2165static int param_get_event_clearing(char *buffer,
2166				    const struct kernel_param *kp)
2167{
2168	switch (ec_event_clearing) {
2169	case ACPI_EC_EVT_TIMING_STATUS:
2170		return sprintf(buffer, "status\n");
2171	case ACPI_EC_EVT_TIMING_QUERY:
2172		return sprintf(buffer, "query\n");
2173	case ACPI_EC_EVT_TIMING_EVENT:
2174		return sprintf(buffer, "event\n");
2175	default:
2176		return sprintf(buffer, "invalid\n");
2177	}
2178	return 0;
2179}
2180
2181module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2182		  NULL, 0644);
2183MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2184
2185static struct acpi_driver acpi_ec_driver = {
2186	.name = "ec",
2187	.class = ACPI_EC_CLASS,
2188	.ids = ec_device_ids,
2189	.ops = {
2190		.add = acpi_ec_add,
2191		.remove = acpi_ec_remove,
2192		},
2193	.drv.pm = &acpi_ec_pm,
2194};
2195
2196static void acpi_ec_destroy_workqueues(void)
2197{
2198	if (ec_wq) {
2199		destroy_workqueue(ec_wq);
2200		ec_wq = NULL;
2201	}
2202	if (ec_query_wq) {
2203		destroy_workqueue(ec_query_wq);
2204		ec_query_wq = NULL;
2205	}
2206}
2207
2208static int acpi_ec_init_workqueues(void)
2209{
2210	if (!ec_wq)
2211		ec_wq = alloc_ordered_workqueue("kec", 0);
2212
2213	if (!ec_query_wq)
2214		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2215
2216	if (!ec_wq || !ec_query_wq) {
2217		acpi_ec_destroy_workqueues();
2218		return -ENODEV;
2219	}
2220	return 0;
2221}
2222
2223static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2224	{
2225		.matches = {
2226			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2227			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2228		},
2229	},
2230	{
2231		.matches = {
2232			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2233			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2234		},
2235	},
2236	{
2237		.matches = {
2238			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2239			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2240		},
2241	},
2242	{ },
2243};
2244
2245void __init acpi_ec_init(void)
2246{
2247	int result;
2248
2249	result = acpi_ec_init_workqueues();
2250	if (result)
2251		return;
2252
2253	/*
2254	 * Disable EC wakeup on following systems to prevent periodic
2255	 * wakeup from EC GPE.
2256	 */
2257	if (dmi_check_system(acpi_ec_no_wakeup)) {
2258		ec_no_wakeup = true;
2259		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2260	}
2261
2262	/* Driver must be registered after acpi_ec_init_workqueues(). */
2263	acpi_bus_register_driver(&acpi_ec_driver);
2264
2265	acpi_ec_ecdt_start();
2266}
2267
2268/* EC driver currently not unloadable */
2269#if 0
2270static void __exit acpi_ec_exit(void)
2271{
2272
2273	acpi_bus_unregister_driver(&acpi_ec_driver);
2274	acpi_ec_destroy_workqueues();
2275}
2276#endif	/* 0 */