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	if (t->rdata)
 787		memset(t->rdata, 0, t->rlen);
 788
 789	/* start transaction */
 790	spin_lock_irqsave(&ec->lock, tmp);
 791	/* Enable GPE for command processing (IBF=0/OBF=1) */
 792	if (!acpi_ec_submit_flushable_request(ec)) {
 793		ret = -EINVAL;
 794		goto unlock;
 795	}
 796	ec_dbg_ref(ec, "Increase command");
 797	/* following two actions should be kept atomic */
 798	ec->curr = t;
 799	ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 800	start_transaction(ec);
 801	spin_unlock_irqrestore(&ec->lock, tmp);
 802
 803	ret = ec_poll(ec);
 804
 805	spin_lock_irqsave(&ec->lock, tmp);
 806	if (t->irq_count == ec_storm_threshold)
 807		acpi_ec_unmask_events(ec);
 808	ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 809	ec->curr = NULL;
 810	/* Disable GPE for command processing (IBF=0/OBF=1) */
 811	acpi_ec_complete_request(ec);
 812	ec_dbg_ref(ec, "Decrease command");
 813unlock:
 814	spin_unlock_irqrestore(&ec->lock, tmp);
 815	return ret;
 816}
 817
 818static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 819{
 820	int status;
 821	u32 glk;
 822
 823	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 824		return -EINVAL;
 
 
 825
 826	mutex_lock(&ec->mutex);
 827	if (ec->global_lock) {
 828		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 829		if (ACPI_FAILURE(status)) {
 830			status = -ENODEV;
 831			goto unlock;
 832		}
 833	}
 834
 835	status = acpi_ec_transaction_unlocked(ec, t);
 836
 837	if (ec->global_lock)
 838		acpi_release_global_lock(glk);
 839unlock:
 840	mutex_unlock(&ec->mutex);
 841	return status;
 842}
 843
 844static int acpi_ec_burst_enable(struct acpi_ec *ec)
 845{
 846	u8 d;
 847	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 848				.wdata = NULL, .rdata = &d,
 849				.wlen = 0, .rlen = 1};
 850
 851	return acpi_ec_transaction_unlocked(ec, &t);
 852}
 853
 854static int acpi_ec_burst_disable(struct acpi_ec *ec)
 855{
 856	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 857				.wdata = NULL, .rdata = NULL,
 858				.wlen = 0, .rlen = 0};
 859
 860	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 861				acpi_ec_transaction_unlocked(ec, &t) : 0;
 862}
 863
 864static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 865{
 866	int result;
 867	u8 d;
 868	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 869				.wdata = &address, .rdata = &d,
 870				.wlen = 1, .rlen = 1};
 871
 872	result = acpi_ec_transaction(ec, &t);
 873	*data = d;
 874	return result;
 875}
 876
 877static int acpi_ec_read_unlocked(struct acpi_ec *ec, u8 address, u8 *data)
 878{
 879	int result;
 880	u8 d;
 881	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 882				.wdata = &address, .rdata = &d,
 883				.wlen = 1, .rlen = 1};
 884
 885	result = acpi_ec_transaction_unlocked(ec, &t);
 886	*data = d;
 887	return result;
 888}
 889
 890static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 891{
 892	u8 wdata[2] = { address, data };
 893	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 894				.wdata = wdata, .rdata = NULL,
 895				.wlen = 2, .rlen = 0};
 896
 897	return acpi_ec_transaction(ec, &t);
 898}
 899
 900static int acpi_ec_write_unlocked(struct acpi_ec *ec, u8 address, u8 data)
 901{
 902	u8 wdata[2] = { address, data };
 903	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 904				.wdata = wdata, .rdata = NULL,
 905				.wlen = 2, .rlen = 0};
 906
 907	return acpi_ec_transaction_unlocked(ec, &t);
 908}
 909
 910int ec_read(u8 addr, u8 *val)
 911{
 912	int err;
 913	u8 temp_data;
 914
 915	if (!first_ec)
 916		return -ENODEV;
 917
 918	err = acpi_ec_read(first_ec, addr, &temp_data);
 919
 920	if (!err) {
 921		*val = temp_data;
 922		return 0;
 923	}
 924	return err;
 925}
 926EXPORT_SYMBOL(ec_read);
 927
 928int ec_write(u8 addr, u8 val)
 929{
 930	if (!first_ec)
 931		return -ENODEV;
 932
 933	return acpi_ec_write(first_ec, addr, val);
 934}
 935EXPORT_SYMBOL(ec_write);
 936
 937int ec_transaction(u8 command,
 938		   const u8 *wdata, unsigned wdata_len,
 939		   u8 *rdata, unsigned rdata_len)
 940{
 941	struct transaction t = {.command = command,
 942				.wdata = wdata, .rdata = rdata,
 943				.wlen = wdata_len, .rlen = rdata_len};
 944
 945	if (!first_ec)
 946		return -ENODEV;
 947
 948	return acpi_ec_transaction(first_ec, &t);
 949}
 950EXPORT_SYMBOL(ec_transaction);
 951
 952/* Get the handle to the EC device */
 953acpi_handle ec_get_handle(void)
 954{
 955	if (!first_ec)
 956		return NULL;
 957	return first_ec->handle;
 958}
 959EXPORT_SYMBOL(ec_get_handle);
 960
 961static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 962{
 963	unsigned long flags;
 964
 965	spin_lock_irqsave(&ec->lock, flags);
 966	if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 967		ec_dbg_drv("Starting EC");
 968		/* Enable GPE for event processing (SCI_EVT=1) */
 969		if (!resuming) {
 970			acpi_ec_submit_request(ec);
 971			ec_dbg_ref(ec, "Increase driver");
 972		}
 973		ec_log_drv("EC started");
 974	}
 975	spin_unlock_irqrestore(&ec->lock, flags);
 976}
 977
 978static bool acpi_ec_stopped(struct acpi_ec *ec)
 979{
 980	unsigned long flags;
 981	bool flushed;
 982
 983	spin_lock_irqsave(&ec->lock, flags);
 984	flushed = acpi_ec_flushed(ec);
 985	spin_unlock_irqrestore(&ec->lock, flags);
 986	return flushed;
 987}
 988
 989static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 990{
 991	unsigned long flags;
 992
 993	spin_lock_irqsave(&ec->lock, flags);
 994	if (acpi_ec_started(ec)) {
 995		ec_dbg_drv("Stopping EC");
 996		set_bit(EC_FLAGS_STOPPED, &ec->flags);
 997		spin_unlock_irqrestore(&ec->lock, flags);
 998		wait_event(ec->wait, acpi_ec_stopped(ec));
 999		spin_lock_irqsave(&ec->lock, flags);
1000		/* Disable GPE for event processing (SCI_EVT=1) */
1001		if (!suspending) {
1002			acpi_ec_complete_request(ec);
1003			ec_dbg_ref(ec, "Decrease driver");
1004		} else if (!ec_freeze_events)
1005			__acpi_ec_disable_event(ec);
1006		clear_bit(EC_FLAGS_STARTED, &ec->flags);
1007		clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1008		ec_log_drv("EC stopped");
1009	}
1010	spin_unlock_irqrestore(&ec->lock, flags);
1011}
1012
1013static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1014{
1015	unsigned long flags;
1016
1017	spin_lock_irqsave(&ec->lock, flags);
1018	ec->busy_polling = true;
1019	ec->polling_guard = 0;
1020	ec_log_drv("interrupt blocked");
1021	spin_unlock_irqrestore(&ec->lock, flags);
1022}
1023
1024static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1025{
1026	unsigned long flags;
1027
1028	spin_lock_irqsave(&ec->lock, flags);
1029	ec->busy_polling = ec_busy_polling;
1030	ec->polling_guard = ec_polling_guard;
1031	ec_log_drv("interrupt unblocked");
1032	spin_unlock_irqrestore(&ec->lock, flags);
1033}
1034
1035void acpi_ec_block_transactions(void)
1036{
1037	struct acpi_ec *ec = first_ec;
1038
1039	if (!ec)
1040		return;
1041
1042	mutex_lock(&ec->mutex);
1043	/* Prevent transactions from being carried out */
1044	acpi_ec_stop(ec, true);
1045	mutex_unlock(&ec->mutex);
1046}
1047
1048void acpi_ec_unblock_transactions(void)
1049{
1050	/*
1051	 * Allow transactions to happen again (this function is called from
1052	 * atomic context during wakeup, so we don't need to acquire the mutex).
1053	 */
1054	if (first_ec)
1055		acpi_ec_start(first_ec, true);
1056}
1057
1058/* --------------------------------------------------------------------------
1059                                Event Management
1060   -------------------------------------------------------------------------- */
1061static struct acpi_ec_query_handler *
1062acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1063{
1064	struct acpi_ec_query_handler *handler;
1065
1066	mutex_lock(&ec->mutex);
1067	list_for_each_entry(handler, &ec->list, node) {
1068		if (value == handler->query_bit) {
1069			kref_get(&handler->kref);
1070			mutex_unlock(&ec->mutex);
1071			return handler;
1072		}
1073	}
1074	mutex_unlock(&ec->mutex);
1075	return NULL;
1076}
1077
1078static void acpi_ec_query_handler_release(struct kref *kref)
1079{
1080	struct acpi_ec_query_handler *handler =
1081		container_of(kref, struct acpi_ec_query_handler, kref);
1082
1083	kfree(handler);
1084}
1085
1086static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1087{
1088	kref_put(&handler->kref, acpi_ec_query_handler_release);
1089}
1090
1091int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1092			      acpi_handle handle, acpi_ec_query_func func,
1093			      void *data)
1094{
1095	struct acpi_ec_query_handler *handler;
1096
1097	if (!handle && !func)
1098		return -EINVAL;
1099
1100	handler = kzalloc(sizeof(*handler), GFP_KERNEL);
1101	if (!handler)
1102		return -ENOMEM;
1103
1104	handler->query_bit = query_bit;
1105	handler->handle = handle;
1106	handler->func = func;
1107	handler->data = data;
1108	mutex_lock(&ec->mutex);
1109	kref_init(&handler->kref);
1110	list_add(&handler->node, &ec->list);
1111	mutex_unlock(&ec->mutex);
1112
1113	return 0;
1114}
1115EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1116
1117static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1118					  bool remove_all, u8 query_bit)
1119{
1120	struct acpi_ec_query_handler *handler, *tmp;
1121	LIST_HEAD(free_list);
1122
1123	mutex_lock(&ec->mutex);
1124	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1125		/*
1126		 * When remove_all is false, only remove custom query handlers
1127		 * which have handler->func set. This is done to preserve query
1128		 * handlers discovered thru ACPI, as they should continue handling
1129		 * EC queries.
1130		 */
1131		if (remove_all || (handler->func && handler->query_bit == query_bit)) {
1132			list_del_init(&handler->node);
1133			list_add(&handler->node, &free_list);
1134
1135		}
1136	}
1137	mutex_unlock(&ec->mutex);
1138	list_for_each_entry_safe(handler, tmp, &free_list, node)
1139		acpi_ec_put_query_handler(handler);
1140}
1141
1142void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1143{
1144	acpi_ec_remove_query_handlers(ec, false, query_bit);
1145	flush_workqueue(ec_query_wq);
1146}
1147EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1148
1149static void acpi_ec_event_processor(struct work_struct *work)
1150{
1151	struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1152	struct acpi_ec_query_handler *handler = q->handler;
1153	struct acpi_ec *ec = q->ec;
1154
1155	ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1156
1157	if (handler->func)
1158		handler->func(handler->data);
1159	else if (handler->handle)
1160		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1161
1162	ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1163
1164	spin_lock_irq(&ec->lock);
1165	ec->queries_in_progress--;
1166	spin_unlock_irq(&ec->lock);
1167
1168	acpi_ec_put_query_handler(handler);
1169	kfree(q);
1170}
1171
1172static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1173{
1174	struct acpi_ec_query *q;
1175	struct transaction *t;
1176
1177	q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1178	if (!q)
1179		return NULL;
1180
1181	INIT_WORK(&q->work, acpi_ec_event_processor);
1182	t = &q->transaction;
1183	t->command = ACPI_EC_COMMAND_QUERY;
1184	t->rdata = pval;
1185	t->rlen = 1;
1186	q->ec = ec;
1187	return q;
1188}
1189
1190static int acpi_ec_submit_query(struct acpi_ec *ec)
1191{
1192	struct acpi_ec_query *q;
1193	u8 value = 0;
1194	int result;
1195
1196	q = acpi_ec_create_query(ec, &value);
1197	if (!q)
1198		return -ENOMEM;
1199
1200	/*
1201	 * Query the EC to find out which _Qxx method we need to evaluate.
1202	 * Note that successful completion of the query causes the ACPI_EC_SCI
1203	 * bit to be cleared (and thus clearing the interrupt source).
1204	 */
1205	result = acpi_ec_transaction(ec, &q->transaction);
1206	if (result)
1207		goto err_exit;
1208
1209	if (!value) {
1210		result = -ENODATA;
1211		goto err_exit;
1212	}
1213
1214	q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1215	if (!q->handler) {
1216		result = -ENODATA;
1217		goto err_exit;
1218	}
1219
1220	/*
1221	 * It is reported that _Qxx are evaluated in a parallel way on Windows:
1222	 * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1223	 *
1224	 * Put this log entry before queue_work() to make it appear in the log
1225	 * before any other messages emitted during workqueue handling.
1226	 */
1227	ec_dbg_evt("Query(0x%02x) scheduled", value);
1228
1229	spin_lock_irq(&ec->lock);
1230
1231	ec->queries_in_progress++;
1232	queue_work(ec_query_wq, &q->work);
1233
1234	spin_unlock_irq(&ec->lock);
1235
1236	return 0;
1237
1238err_exit:
1239	kfree(q);
1240
1241	return result;
1242}
1243
1244static void acpi_ec_event_handler(struct work_struct *work)
1245{
1246	struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1247
1248	ec_dbg_evt("Event started");
1249
1250	spin_lock_irq(&ec->lock);
1251
1252	while (ec->events_to_process) {
1253		spin_unlock_irq(&ec->lock);
1254
1255		acpi_ec_submit_query(ec);
1256
1257		spin_lock_irq(&ec->lock);
1258
1259		ec->events_to_process--;
1260	}
1261
1262	/*
1263	 * Before exit, make sure that the it will be possible to queue up the
1264	 * event handling work again regardless of whether or not the query
1265	 * queued up above is processed successfully.
1266	 */
1267	if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1268		bool guard_timeout;
1269
1270		acpi_ec_complete_event(ec);
1271
1272		ec_dbg_evt("Event stopped");
1273
1274		spin_unlock_irq(&ec->lock);
1275
1276		guard_timeout = !!ec_guard(ec);
1277
1278		spin_lock_irq(&ec->lock);
1279
1280		/* Take care of SCI_EVT unless someone else is doing that. */
1281		if (guard_timeout && !ec->curr)
1282			advance_transaction(ec, false);
1283	} else {
1284		acpi_ec_close_event(ec);
1285
1286		ec_dbg_evt("Event stopped");
1287	}
1288
1289	ec->events_in_progress--;
1290
1291	spin_unlock_irq(&ec->lock);
1292}
1293
1294static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
1295{
1296	/*
1297	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
1298	 * changes to always trigger a GPE interrupt.
1299	 *
1300	 * GPE STS is a W1C register, which means:
1301	 *
1302	 * 1. Software can clear it without worrying about clearing the other
1303	 *    GPEs' STS bits when the hardware sets them in parallel.
1304	 *
1305	 * 2. As long as software can ensure only clearing it when it is set,
1306	 *    hardware won't set it in parallel.
1307	 */
1308	if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
1309		acpi_clear_gpe(NULL, ec->gpe);
1310
1311	advance_transaction(ec, true);
1312}
1313
1314static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1315{
1316	unsigned long flags;
1317
1318	spin_lock_irqsave(&ec->lock, flags);
1319
1320	clear_gpe_and_advance_transaction(ec, true);
1321
1322	spin_unlock_irqrestore(&ec->lock, flags);
1323}
1324
1325static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1326			       u32 gpe_number, void *data)
1327{
1328	acpi_ec_handle_interrupt(data);
1329	return ACPI_INTERRUPT_HANDLED;
1330}
1331
1332static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1333{
1334	acpi_ec_handle_interrupt(data);
1335	return IRQ_HANDLED;
1336}
1337
1338/* --------------------------------------------------------------------------
1339 *                           Address Space Management
1340 * -------------------------------------------------------------------------- */
1341
1342static acpi_status
1343acpi_ec_space_handler(u32 function, acpi_physical_address address,
1344		      u32 bits, u64 *value64,
1345		      void *handler_context, void *region_context)
1346{
1347	struct acpi_ec *ec = handler_context;
1348	int result = 0, i, bytes = bits / 8;
1349	u8 *value = (u8 *)value64;
1350	u32 glk;
1351
1352	if ((address > 0xFF) || !value || !handler_context)
1353		return AE_BAD_PARAMETER;
1354
1355	if (function != ACPI_READ && function != ACPI_WRITE)
1356		return AE_BAD_PARAMETER;
1357
1358	mutex_lock(&ec->mutex);
1359
1360	if (ec->global_lock) {
1361		acpi_status status;
1362
1363		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
1364		if (ACPI_FAILURE(status)) {
1365			result = -ENODEV;
1366			goto unlock;
1367		}
1368	}
1369
1370	if (ec->busy_polling || bits > 8)
1371		acpi_ec_burst_enable(ec);
1372
1373	for (i = 0; i < bytes; ++i, ++address, ++value) {
1374		result = (function == ACPI_READ) ?
1375			acpi_ec_read_unlocked(ec, address, value) :
1376			acpi_ec_write_unlocked(ec, address, *value);
1377		if (result < 0)
1378			break;
1379	}
1380
1381	if (ec->busy_polling || bits > 8)
1382		acpi_ec_burst_disable(ec);
1383
1384	if (ec->global_lock)
1385		acpi_release_global_lock(glk);
1386
1387unlock:
1388	mutex_unlock(&ec->mutex);
1389
1390	switch (result) {
1391	case -EINVAL:
1392		return AE_BAD_PARAMETER;
1393	case -ENODEV:
1394		return AE_NOT_FOUND;
1395	case -ETIME:
1396		return AE_TIME;
1397	case 0:
1398		return AE_OK;
1399	default:
1400		return AE_ERROR;
1401	}
1402}
1403
1404/* --------------------------------------------------------------------------
1405 *                             Driver Interface
1406 * -------------------------------------------------------------------------- */
1407
1408static acpi_status
1409ec_parse_io_ports(struct acpi_resource *resource, void *context);
1410
1411static void acpi_ec_free(struct acpi_ec *ec)
1412{
1413	if (first_ec == ec)
1414		first_ec = NULL;
1415	if (boot_ec == ec)
1416		boot_ec = NULL;
1417	kfree(ec);
1418}
1419
1420static struct acpi_ec *acpi_ec_alloc(void)
1421{
1422	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1423
1424	if (!ec)
1425		return NULL;
1426	mutex_init(&ec->mutex);
1427	init_waitqueue_head(&ec->wait);
1428	INIT_LIST_HEAD(&ec->list);
1429	spin_lock_init(&ec->lock);
1430	INIT_WORK(&ec->work, acpi_ec_event_handler);
1431	ec->timestamp = jiffies;
1432	ec->busy_polling = true;
1433	ec->polling_guard = 0;
1434	ec->gpe = -1;
1435	ec->irq = -1;
1436	return ec;
1437}
1438
1439static acpi_status
1440acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1441			       void *context, void **return_value)
1442{
1443	char node_name[5];
1444	struct acpi_buffer buffer = { sizeof(node_name), node_name };
1445	struct acpi_ec *ec = context;
1446	int value = 0;
1447	acpi_status status;
1448
1449	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1450
1451	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1452		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1453	return AE_OK;
1454}
1455
1456static acpi_status
1457ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1458{
1459	acpi_status status;
1460	unsigned long long tmp = 0;
1461	struct acpi_ec *ec = context;
1462
1463	/* clear addr values, ec_parse_io_ports depend on it */
1464	ec->command_addr = ec->data_addr = 0;
1465
1466	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1467				     ec_parse_io_ports, ec);
1468	if (ACPI_FAILURE(status))
1469		return status;
1470	if (ec->data_addr == 0 || ec->command_addr == 0)
1471		return AE_OK;
1472
1473	/* Get GPE bit assignment (EC events). */
1474	/* TODO: Add support for _GPE returning a package */
1475	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1476	if (ACPI_SUCCESS(status))
1477		ec->gpe = tmp;
1478	/*
1479	 * Errors are non-fatal, allowing for ACPI Reduced Hardware
1480	 * platforms which use GpioInt instead of GPE.
1481	 */
1482
1483	/* Use the global lock for all EC transactions? */
1484	tmp = 0;
1485	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1486	ec->global_lock = tmp;
1487	ec->handle = handle;
1488	return AE_CTRL_TERMINATE;
1489}
1490
1491static bool install_gpe_event_handler(struct acpi_ec *ec)
1492{
1493	acpi_status status;
1494
1495	status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1496					      ACPI_GPE_EDGE_TRIGGERED,
1497					      &acpi_ec_gpe_handler, ec);
1498	if (ACPI_FAILURE(status))
1499		return false;
1500
1501	if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1502		acpi_ec_enable_gpe(ec, true);
1503
1504	return true;
1505}
1506
1507static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1508{
1509	return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
1510				    IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
1511}
1512
1513/**
1514 * ec_install_handlers - Install service callbacks and register query methods.
1515 * @ec: Target EC.
1516 * @device: ACPI device object corresponding to @ec.
1517 * @call_reg: If _REG should be called to notify OpRegion availability
1518 *
1519 * Install a handler for the EC address space type unless it has been installed
1520 * already.  If @device is not NULL, also look for EC query methods in the
1521 * namespace and register them, and install an event (either GPE or GPIO IRQ)
1522 * handler for the EC, if possible.
1523 *
1524 * Return:
1525 * -ENODEV if the address space handler cannot be installed, which means
1526 *  "unable to handle transactions",
1527 * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1528 * or 0 (success) otherwise.
1529 */
1530static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1531			       bool call_reg)
1532{
1533	acpi_status status;
1534
1535	acpi_ec_start(ec, false);
1536
1537	if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1538		acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1539
1540		acpi_ec_enter_noirq(ec);
1541		status = acpi_install_address_space_handler_no_reg(scope_handle,
1542								   ACPI_ADR_SPACE_EC,
1543								   &acpi_ec_space_handler,
1544								   NULL, ec);
1545		if (ACPI_FAILURE(status)) {
1546			acpi_ec_stop(ec, false);
1547			return -ENODEV;
1548		}
1549		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
 
1550	}
1551
1552	if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1553		acpi_execute_reg_methods(ec->handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
1554		set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1555	}
1556
1557	if (!device)
1558		return 0;
1559
1560	if (ec->gpe < 0) {
1561		/* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1562		int irq = acpi_dev_gpio_irq_get(device, 0);
1563		/*
1564		 * Bail out right away for deferred probing or complete the
1565		 * initialization regardless of any other errors.
1566		 */
1567		if (irq == -EPROBE_DEFER)
1568			return -EPROBE_DEFER;
1569		else if (irq >= 0)
1570			ec->irq = irq;
1571	}
1572
1573	if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1574		/* Find and register all query methods */
1575		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1576				    acpi_ec_register_query_methods,
1577				    NULL, ec, NULL);
1578		set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1579	}
1580	if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1581		bool ready = false;
1582
1583		if (ec->gpe >= 0)
1584			ready = install_gpe_event_handler(ec);
1585		else if (ec->irq >= 0)
1586			ready = install_gpio_irq_event_handler(ec);
1587
1588		if (ready) {
1589			set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1590			acpi_ec_leave_noirq(ec);
1591		}
1592		/*
1593		 * Failures to install an event handler are not fatal, because
1594		 * the EC can be polled for events.
1595		 */
1596	}
1597	/* EC is fully operational, allow queries */
1598	acpi_ec_enable_event(ec);
1599
1600	return 0;
1601}
1602
1603static void ec_remove_handlers(struct acpi_ec *ec)
1604{
1605	acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1606
1607	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1608		if (ACPI_FAILURE(acpi_remove_address_space_handler(
1609						scope_handle,
1610						ACPI_ADR_SPACE_EC,
1611						&acpi_ec_space_handler)))
1612			pr_err("failed to remove space handler\n");
1613		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1614	}
1615
1616	/*
1617	 * Stops handling the EC transactions after removing the operation
1618	 * region handler. This is required because _REG(DISCONNECT)
1619	 * invoked during the removal can result in new EC transactions.
1620	 *
1621	 * Flushes the EC requests and thus disables the GPE before
1622	 * removing the GPE handler. This is required by the current ACPICA
1623	 * GPE core. ACPICA GPE core will automatically disable a GPE when
1624	 * it is indicated but there is no way to handle it. So the drivers
1625	 * must disable the GPEs prior to removing the GPE handlers.
1626	 */
1627	acpi_ec_stop(ec, false);
1628
1629	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1630		if (ec->gpe >= 0 &&
1631		    ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1632				 &acpi_ec_gpe_handler)))
1633			pr_err("failed to remove gpe handler\n");
1634
1635		if (ec->irq >= 0)
1636			free_irq(ec->irq, ec);
1637
1638		clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1639	}
1640	if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1641		acpi_ec_remove_query_handlers(ec, true, 0);
1642		clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1643	}
1644}
1645
1646static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1647{
1648	int ret;
1649
 
 
 
 
1650	/* First EC capable of handling transactions */
1651	if (!first_ec)
1652		first_ec = ec;
1653
1654	ret = ec_install_handlers(ec, device, call_reg);
1655	if (ret) {
1656		if (ec == first_ec)
1657			first_ec = NULL;
1658
1659		return ret;
1660	}
1661
1662	pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1663		ec->data_addr);
1664
1665	if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1666		if (ec->gpe >= 0)
1667			pr_info("GPE=0x%x\n", ec->gpe);
1668		else
1669			pr_info("IRQ=%d\n", ec->irq);
1670	}
1671
1672	return ret;
1673}
1674
1675static int acpi_ec_add(struct acpi_device *device)
1676{
1677	struct acpi_ec *ec;
1678	int ret;
1679
1680	strscpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1681	strscpy(acpi_device_class(device), ACPI_EC_CLASS);
1682
1683	if (boot_ec && (boot_ec->handle == device->handle ||
1684	    !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1685		/* Fast path: this device corresponds to the boot EC. */
1686		ec = boot_ec;
1687	} else {
1688		acpi_status status;
1689
1690		ec = acpi_ec_alloc();
1691		if (!ec)
1692			return -ENOMEM;
1693
1694		status = ec_parse_device(device->handle, 0, ec, NULL);
1695		if (status != AE_CTRL_TERMINATE) {
1696			ret = -EINVAL;
1697			goto err;
1698		}
1699
1700		if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1701		    ec->data_addr == boot_ec->data_addr) {
1702			/*
1703			 * Trust PNP0C09 namespace location rather than ECDT ID.
1704			 * But trust ECDT GPE rather than _GPE because of ASUS
1705			 * quirks. So do not change boot_ec->gpe to ec->gpe,
1706			 * except when the TRUST_DSDT_GPE quirk is set.
1707			 */
1708			boot_ec->handle = ec->handle;
1709
1710			if (EC_FLAGS_TRUST_DSDT_GPE)
1711				boot_ec->gpe = ec->gpe;
1712
1713			acpi_handle_debug(ec->handle, "duplicated.\n");
1714			acpi_ec_free(ec);
1715			ec = boot_ec;
1716		}
1717	}
1718
1719	ret = acpi_ec_setup(ec, device, true);
1720	if (ret)
1721		goto err;
1722
1723	if (ec == boot_ec)
1724		acpi_handle_info(boot_ec->handle,
1725				 "Boot %s EC initialization complete\n",
1726				 boot_ec_is_ecdt ? "ECDT" : "DSDT");
1727
1728	acpi_handle_info(ec->handle,
1729			 "EC: Used to handle transactions and events\n");
1730
1731	device->driver_data = ec;
1732
1733	ret = !!request_region(ec->data_addr, 1, "EC data");
1734	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1735	ret = !!request_region(ec->command_addr, 1, "EC cmd");
1736	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1737
1738	/* Reprobe devices depending on the EC */
1739	acpi_dev_clear_dependencies(device);
1740
1741	acpi_handle_debug(ec->handle, "enumerated.\n");
1742	return 0;
1743
1744err:
1745	if (ec != boot_ec)
1746		acpi_ec_free(ec);
1747
1748	return ret;
1749}
1750
1751static void acpi_ec_remove(struct acpi_device *device)
1752{
1753	struct acpi_ec *ec;
1754
1755	if (!device)
1756		return;
1757
1758	ec = acpi_driver_data(device);
1759	release_region(ec->data_addr, 1);
1760	release_region(ec->command_addr, 1);
1761	device->driver_data = NULL;
1762	if (ec != boot_ec) {
1763		ec_remove_handlers(ec);
1764		acpi_ec_free(ec);
1765	}
1766}
1767
1768void acpi_ec_register_opregions(struct acpi_device *adev)
1769{
1770	if (first_ec && first_ec->handle != adev->handle)
1771		acpi_execute_reg_methods(adev->handle, 1, ACPI_ADR_SPACE_EC);
1772}
1773
1774static acpi_status
1775ec_parse_io_ports(struct acpi_resource *resource, void *context)
1776{
1777	struct acpi_ec *ec = context;
1778
1779	if (resource->type != ACPI_RESOURCE_TYPE_IO)
1780		return AE_OK;
1781
1782	/*
1783	 * The first address region returned is the data port, and
1784	 * the second address region returned is the status/command
1785	 * port.
1786	 */
1787	if (ec->data_addr == 0)
1788		ec->data_addr = resource->data.io.minimum;
1789	else if (ec->command_addr == 0)
1790		ec->command_addr = resource->data.io.minimum;
1791	else
1792		return AE_CTRL_TERMINATE;
1793
1794	return AE_OK;
1795}
1796
1797static const struct acpi_device_id ec_device_ids[] = {
1798	{"PNP0C09", 0},
1799	{ACPI_ECDT_HID, 0},
1800	{"", 0},
1801};
1802
1803/*
1804 * This function is not Windows-compatible as Windows never enumerates the
1805 * namespace EC before the main ACPI device enumeration process. It is
1806 * retained for historical reason and will be deprecated in the future.
1807 */
1808void __init acpi_ec_dsdt_probe(void)
1809{
1810	struct acpi_ec *ec;
1811	acpi_status status;
1812	int ret;
1813
1814	/*
1815	 * If a platform has ECDT, there is no need to proceed as the
1816	 * following probe is not a part of the ACPI device enumeration,
1817	 * executing _STA is not safe, and thus this probe may risk of
1818	 * picking up an invalid EC device.
1819	 */
1820	if (boot_ec)
1821		return;
1822
1823	ec = acpi_ec_alloc();
1824	if (!ec)
1825		return;
1826
1827	/*
1828	 * At this point, the namespace is initialized, so start to find
1829	 * the namespace objects.
1830	 */
1831	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1832	if (ACPI_FAILURE(status) || !ec->handle) {
1833		acpi_ec_free(ec);
1834		return;
1835	}
1836
1837	/*
1838	 * When the DSDT EC is available, always re-configure boot EC to
1839	 * have _REG evaluated. _REG can only be evaluated after the
1840	 * namespace initialization.
1841	 * At this point, the GPE is not fully initialized, so do not to
1842	 * handle the events.
1843	 */
1844	ret = acpi_ec_setup(ec, NULL, true);
1845	if (ret) {
1846		acpi_ec_free(ec);
1847		return;
1848	}
1849
1850	boot_ec = ec;
1851
1852	acpi_handle_info(ec->handle,
1853			 "Boot DSDT EC used to handle transactions\n");
1854}
1855
1856/*
1857 * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1858 *
1859 * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1860 * found a matching object in the namespace.
1861 *
1862 * Next, in case the DSDT EC is not functioning, it is still necessary to
1863 * provide a functional ECDT EC to handle events, so add an extra device object
1864 * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1865 *
1866 * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1867 * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1868 */
1869static void __init acpi_ec_ecdt_start(void)
1870{
1871	struct acpi_table_ecdt *ecdt_ptr;
1872	acpi_handle handle;
1873	acpi_status status;
1874
1875	/* Bail out if a matching EC has been found in the namespace. */
1876	if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1877		return;
1878
1879	/* Look up the object pointed to from the ECDT in the namespace. */
1880	status = acpi_get_table(ACPI_SIG_ECDT, 1,
1881				(struct acpi_table_header **)&ecdt_ptr);
1882	if (ACPI_FAILURE(status))
1883		return;
1884
1885	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1886	if (ACPI_SUCCESS(status)) {
1887		boot_ec->handle = handle;
1888
1889		/* Add a special ACPI device object to represent the boot EC. */
1890		acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1891	}
1892
1893	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1894}
1895
1896/*
1897 * On some hardware it is necessary to clear events accumulated by the EC during
1898 * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1899 * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1900 *
1901 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1902 *
1903 * Ideally, the EC should also be instructed NOT to accumulate events during
1904 * sleep (which Windows seems to do somehow), but the interface to control this
1905 * behaviour is not known at this time.
1906 *
1907 * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1908 * however it is very likely that other Samsung models are affected.
1909 *
1910 * On systems which don't accumulate _Q events during sleep, this extra check
1911 * should be harmless.
1912 */
1913static int ec_clear_on_resume(const struct dmi_system_id *id)
1914{
1915	pr_debug("Detected system needing EC poll on resume.\n");
1916	EC_FLAGS_CLEAR_ON_RESUME = 1;
1917	ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1918	return 0;
1919}
1920
1921/*
1922 * Some ECDTs contain wrong register addresses.
1923 * MSI MS-171F
1924 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1925 */
1926static int ec_correct_ecdt(const struct dmi_system_id *id)
1927{
1928	pr_debug("Detected system needing ECDT address correction.\n");
1929	EC_FLAGS_CORRECT_ECDT = 1;
1930	return 0;
1931}
1932
1933/*
1934 * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1935 * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1936 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1937 */
1938static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1939{
1940	pr_debug("Detected system needing DSDT GPE setting.\n");
1941	EC_FLAGS_TRUST_DSDT_GPE = 1;
1942	return 0;
1943}
1944
1945static const struct dmi_system_id ec_dmi_table[] __initconst = {
1946	{
1947		/*
1948		 * MSI MS-171F
1949		 * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1950		 */
1951		.callback = ec_correct_ecdt,
1952		.matches = {
1953			DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1954			DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1955		},
1956	},
1957	{
1958		/*
1959		 * HP Pavilion Gaming Laptop 15-cx0xxx
1960		 * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1961		 */
1962		.callback = ec_honor_dsdt_gpe,
1963		.matches = {
1964			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1965			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1966		},
1967	},
1968	{
1969		/*
1970		 * HP Pavilion Gaming Laptop 15-cx0041ur
1971		 */
1972		.callback = ec_honor_dsdt_gpe,
1973		.matches = {
1974			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1975			DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1976		},
1977	},
1978	{
1979		/*
1980		 * HP Pavilion Gaming Laptop 15-dk1xxx
1981		 * https://github.com/systemd/systemd/issues/28942
1982		 */
1983		.callback = ec_honor_dsdt_gpe,
1984		.matches = {
1985			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1986			DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
1987		},
1988	},
1989	{
1990		/*
1991		 * HP 250 G7 Notebook PC
1992		 */
1993		.callback = ec_honor_dsdt_gpe,
1994		.matches = {
1995			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1996			DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
1997		},
1998	},
1999	{
2000		/*
2001		 * Samsung hardware
2002		 * https://bugzilla.kernel.org/show_bug.cgi?id=44161
2003		 */
2004		.callback = ec_clear_on_resume,
2005		.matches = {
2006			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
2007		},
2008	},
2009	{}
2010};
2011
2012void __init acpi_ec_ecdt_probe(void)
2013{
2014	struct acpi_table_ecdt *ecdt_ptr;
2015	struct acpi_ec *ec;
2016	acpi_status status;
2017	int ret;
2018
2019	/* Generate a boot ec context. */
2020	dmi_check_system(ec_dmi_table);
2021	status = acpi_get_table(ACPI_SIG_ECDT, 1,
2022				(struct acpi_table_header **)&ecdt_ptr);
2023	if (ACPI_FAILURE(status))
2024		return;
2025
2026	if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
2027		/*
2028		 * Asus X50GL:
2029		 * https://bugzilla.kernel.org/show_bug.cgi?id=11880
2030		 */
2031		goto out;
2032	}
2033
2034	ec = acpi_ec_alloc();
2035	if (!ec)
2036		goto out;
2037
2038	if (EC_FLAGS_CORRECT_ECDT) {
2039		ec->command_addr = ecdt_ptr->data.address;
2040		ec->data_addr = ecdt_ptr->control.address;
2041	} else {
2042		ec->command_addr = ecdt_ptr->control.address;
2043		ec->data_addr = ecdt_ptr->data.address;
2044	}
2045
2046	/*
2047	 * Ignore the GPE value on Reduced Hardware platforms.
2048	 * Some products have this set to an erroneous value.
2049	 */
2050	if (!acpi_gbl_reduced_hardware)
2051		ec->gpe = ecdt_ptr->gpe;
2052
2053	ec->handle = ACPI_ROOT_OBJECT;
2054
2055	/*
2056	 * At this point, the namespace is not initialized, so do not find
2057	 * the namespace objects, or handle the events.
2058	 */
2059	ret = acpi_ec_setup(ec, NULL, false);
2060	if (ret) {
2061		acpi_ec_free(ec);
2062		goto out;
2063	}
2064
2065	boot_ec = ec;
2066	boot_ec_is_ecdt = true;
2067
2068	pr_info("Boot ECDT EC used to handle transactions\n");
2069
2070out:
2071	acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2072}
2073
2074#ifdef CONFIG_PM_SLEEP
2075static int acpi_ec_suspend(struct device *dev)
2076{
2077	struct acpi_ec *ec =
2078		acpi_driver_data(to_acpi_device(dev));
2079
2080	if (!pm_suspend_no_platform() && ec_freeze_events)
2081		acpi_ec_disable_event(ec);
2082	return 0;
2083}
2084
2085static int acpi_ec_suspend_noirq(struct device *dev)
2086{
2087	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2088
2089	/*
2090	 * The SCI handler doesn't run at this point, so the GPE can be
2091	 * masked at the low level without side effects.
2092	 */
2093	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2094	    ec->gpe >= 0 && ec->reference_count >= 1)
2095		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2096
2097	acpi_ec_enter_noirq(ec);
2098
2099	return 0;
2100}
2101
2102static int acpi_ec_resume_noirq(struct device *dev)
2103{
2104	struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2105
2106	acpi_ec_leave_noirq(ec);
2107
2108	if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2109	    ec->gpe >= 0 && ec->reference_count >= 1)
2110		acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2111
2112	return 0;
2113}
2114
2115static int acpi_ec_resume(struct device *dev)
2116{
2117	struct acpi_ec *ec =
2118		acpi_driver_data(to_acpi_device(dev));
2119
2120	acpi_ec_enable_event(ec);
2121	return 0;
2122}
2123
2124void acpi_ec_mark_gpe_for_wake(void)
2125{
2126	if (first_ec && !ec_no_wakeup)
2127		acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2128}
2129EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2130
2131void acpi_ec_set_gpe_wake_mask(u8 action)
2132{
2133	if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2134		acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2135}
2136
2137static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2138{
2139	return ec->events_in_progress + ec->queries_in_progress > 0;
2140}
2141
2142bool acpi_ec_dispatch_gpe(void)
2143{
2144	bool work_in_progress = false;
2145
2146	if (!first_ec)
2147		return acpi_any_gpe_status_set(U32_MAX);
2148
2149	/*
2150	 * Report wakeup if the status bit is set for any enabled GPE other
2151	 * than the EC one.
2152	 */
2153	if (acpi_any_gpe_status_set(first_ec->gpe))
2154		return true;
2155
2156	/*
2157	 * Cancel the SCI wakeup and process all pending events in case there
2158	 * are any wakeup ones in there.
2159	 *
2160	 * Note that if any non-EC GPEs are active at this point, the SCI will
2161	 * retrigger after the rearming in acpi_s2idle_wake(), so no events
2162	 * should be missed by canceling the wakeup here.
2163	 */
2164	pm_system_cancel_wakeup();
2165
2166	/*
2167	 * Dispatch the EC GPE in-band, but do not report wakeup in any case
2168	 * to allow the caller to process events properly after that.
2169	 */
2170	spin_lock_irq(&first_ec->lock);
2171
2172	if (acpi_ec_gpe_status_set(first_ec)) {
2173		pm_pr_dbg("ACPI EC GPE status set\n");
2174
2175		clear_gpe_and_advance_transaction(first_ec, false);
2176		work_in_progress = acpi_ec_work_in_progress(first_ec);
2177	}
2178
2179	spin_unlock_irq(&first_ec->lock);
2180
2181	if (!work_in_progress)
2182		return false;
2183
2184	pm_pr_dbg("ACPI EC GPE dispatched\n");
2185
2186	/* Drain EC work. */
2187	do {
2188		acpi_ec_flush_work();
2189
2190		pm_pr_dbg("ACPI EC work flushed\n");
2191
2192		spin_lock_irq(&first_ec->lock);
2193
2194		work_in_progress = acpi_ec_work_in_progress(first_ec);
2195
2196		spin_unlock_irq(&first_ec->lock);
2197	} while (work_in_progress && !pm_wakeup_pending());
2198
2199	return false;
2200}
2201#endif /* CONFIG_PM_SLEEP */
2202
2203static const struct dev_pm_ops acpi_ec_pm = {
2204	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2205	SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2206};
2207
2208static int param_set_event_clearing(const char *val,
2209				    const struct kernel_param *kp)
2210{
2211	int result = 0;
2212
2213	if (!strncmp(val, "status", sizeof("status") - 1)) {
2214		ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2215		pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2216	} else if (!strncmp(val, "query", sizeof("query") - 1)) {
2217		ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2218		pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2219	} else if (!strncmp(val, "event", sizeof("event") - 1)) {
2220		ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2221		pr_info("Assuming SCI_EVT clearing on event reads\n");
2222	} else
2223		result = -EINVAL;
2224	return result;
2225}
2226
2227static int param_get_event_clearing(char *buffer,
2228				    const struct kernel_param *kp)
2229{
2230	switch (ec_event_clearing) {
2231	case ACPI_EC_EVT_TIMING_STATUS:
2232		return sprintf(buffer, "status\n");
2233	case ACPI_EC_EVT_TIMING_QUERY:
2234		return sprintf(buffer, "query\n");
2235	case ACPI_EC_EVT_TIMING_EVENT:
2236		return sprintf(buffer, "event\n");
2237	default:
2238		return sprintf(buffer, "invalid\n");
2239	}
2240	return 0;
2241}
2242
2243module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2244		  NULL, 0644);
2245MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2246
2247static struct acpi_driver acpi_ec_driver = {
2248	.name = "ec",
2249	.class = ACPI_EC_CLASS,
2250	.ids = ec_device_ids,
2251	.ops = {
2252		.add = acpi_ec_add,
2253		.remove = acpi_ec_remove,
2254		},
2255	.drv.pm = &acpi_ec_pm,
2256};
2257
2258static void acpi_ec_destroy_workqueues(void)
2259{
2260	if (ec_wq) {
2261		destroy_workqueue(ec_wq);
2262		ec_wq = NULL;
2263	}
2264	if (ec_query_wq) {
2265		destroy_workqueue(ec_query_wq);
2266		ec_query_wq = NULL;
2267	}
2268}
2269
2270static int acpi_ec_init_workqueues(void)
2271{
2272	if (!ec_wq)
2273		ec_wq = alloc_ordered_workqueue("kec", 0);
2274
2275	if (!ec_query_wq)
2276		ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2277
2278	if (!ec_wq || !ec_query_wq) {
2279		acpi_ec_destroy_workqueues();
2280		return -ENODEV;
2281	}
2282	return 0;
2283}
2284
2285static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2286	{
2287		.matches = {
2288			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2289			DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2290		},
2291	},
2292	{
2293		.matches = {
2294			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2295			DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2296		},
2297	},
2298	{
2299		.matches = {
2300			DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2301			DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2302		},
2303	},
2304	{ },
2305};
2306
2307void __init acpi_ec_init(void)
2308{
2309	int result;
2310
2311	result = acpi_ec_init_workqueues();
2312	if (result)
2313		return;
2314
2315	/*
2316	 * Disable EC wakeup on following systems to prevent periodic
2317	 * wakeup from EC GPE.
2318	 */
2319	if (dmi_check_system(acpi_ec_no_wakeup)) {
2320		ec_no_wakeup = true;
2321		pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2322	}
2323
2324	/* Driver must be registered after acpi_ec_init_workqueues(). */
2325	acpi_bus_register_driver(&acpi_ec_driver);
2326
2327	acpi_ec_ecdt_start();
2328}
2329
2330/* EC driver currently not unloadable */
2331#if 0
2332static void __exit acpi_ec_exit(void)
2333{
2334
2335	acpi_bus_unregister_driver(&acpi_ec_driver);
2336	acpi_ec_destroy_workqueues();
2337}
2338#endif	/* 0 */