drivers/acpi/ec.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ec.c - ACPI Embedded Controller Driver (v3)
   4  *
   5  *  Copyright (C) 2001-2015 Intel Corporation
   6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
   7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
   9  *            2004       Luming Yu <luming.yu@intel.com>
  10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
  11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  13  */
  14
  15 /* Uncomment next line to get verbose printout */
  16 /* #define DEBUG */
  17 #define pr_fmt(fmt) "ACPI: EC: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/types.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/list.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/slab.h>
  28 #include <linux/suspend.h>
  29 #include <linux/acpi.h>
  30 #include <linux/dmi.h>
  31 #include <asm/io.h>
  32
  33 #include "internal.h"
  34
  35 #define ACPI_EC_CLASS                   "embedded_controller"
  36 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  37
  38 /* EC status register */
  39 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  40 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  41 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  42 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  43 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  44
  45 /*
  46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  47  * This leads to lots of practical timing issues for the host EC driver.
  48  * The following variations are defined (from the target EC firmware's
  49  * perspective):
  50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  51  *         target can clear SCI_EVT at any time so long as the host can see
  52  *         the indication by reading the status register (EC_SC). So the
  53  *         host should re-check SCI_EVT after the first time the SCI_EVT
  54  *         indication is seen, which is the same time the query request
  55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  56  *         at any later time could indicate another event. Normally such
  57  *         kind of EC firmware has implemented an event queue and will
  58  *         return 0x00 to indicate "no outstanding event".
  59  * QUERY: After seeing the query request (QR_EC) written to the command
  60  *        register (EC_CMD) by the host and having prepared the responding
  61  *        event value in the data register (EC_DATA), the target can safely
  62  *        clear SCI_EVT because the target can confirm that the current
  63  *        event is being handled by the host. The host then should check
  64  *        SCI_EVT right after reading the event response from the data
  65  *        register (EC_DATA).
  66  * EVENT: After seeing the event response read from the data register
  67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  68  *        target requires time to notice the change in the data register
  69  *        (EC_DATA), the host may be required to wait additional guarding
  70  *        time before checking the SCI_EVT again. Such guarding may not be
  71  *        necessary if the host is notified via another IRQ.
  72  */
  73 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  74 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  75 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  76
  77 /* EC commands */
  78 enum ec_command {
  79         ACPI_EC_COMMAND_READ = 0x80,
  80         ACPI_EC_COMMAND_WRITE = 0x81,
  81         ACPI_EC_BURST_ENABLE = 0x82,
  82         ACPI_EC_BURST_DISABLE = 0x83,
  83         ACPI_EC_COMMAND_QUERY = 0x84,
  84 };
  85
  86 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  87 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  88 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
  89 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  90                                          * when trying to clear the EC */
  91 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
  92
  93 enum {
  94         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
  95         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
  96         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
  97         EC_FLAGS_EVENT_HANDLER_INSTALLED,       /* Event handler installed */
  98         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
  99         EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
 100         EC_FLAGS_STARTED,               /* Driver is started */
 101         EC_FLAGS_STOPPED,               /* Driver is stopped */
 102         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 103 };
 104
 105 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 106 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 107
 108 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 109 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 110 module_param(ec_delay, uint, 0644);
 111 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 112
 113 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 114 module_param(ec_max_queries, uint, 0644);
 115 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 116
 117 static bool ec_busy_polling __read_mostly;
 118 module_param(ec_busy_polling, bool, 0644);
 119 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 120
 121 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 122 module_param(ec_polling_guard, uint, 0644);
 123 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 124
 125 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 126
 127 /*
 128  * If the number of false interrupts per one transaction exceeds
 129  * this threshold, will think there is a GPE storm happened and
 130  * will disable the GPE for normal transaction.
 131  */
 132 static unsigned int ec_storm_threshold  __read_mostly = 8;
 133 module_param(ec_storm_threshold, uint, 0644);
 134 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 135
 136 static bool ec_freeze_events __read_mostly = false;
 137 module_param(ec_freeze_events, bool, 0644);
 138 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 139
 140 static bool ec_no_wakeup __read_mostly;
 141 module_param(ec_no_wakeup, bool, 0644);
 142 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 143
 144 struct acpi_ec_query_handler {
 145         struct list_head node;
 146         acpi_ec_query_func func;
 147         acpi_handle handle;
 148         void *data;
 149         u8 query_bit;
 150         struct kref kref;
 151 };
 152
 153 struct transaction {
 154         const u8 *wdata;
 155         u8 *rdata;
 156         unsigned short irq_count;
 157         u8 command;
 158         u8 wi;
 159         u8 ri;
 160         u8 wlen;
 161         u8 rlen;
 162         u8 flags;
 163 };
 164
 165 struct acpi_ec_query {
 166         struct transaction transaction;
 167         struct work_struct work;
 168         struct acpi_ec_query_handler *handler;
 169         struct acpi_ec *ec;
 170 };
 171
 172 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 173 static void advance_transaction(struct acpi_ec *ec);
 174 static void acpi_ec_event_handler(struct work_struct *work);
 175 static void acpi_ec_event_processor(struct work_struct *work);
 176
 177 struct acpi_ec *first_ec;
 178 EXPORT_SYMBOL(first_ec);
 179
 180 static struct acpi_ec *boot_ec;
 181 static bool boot_ec_is_ecdt = false;
 182 static struct workqueue_struct *ec_wq;
 183 static struct workqueue_struct *ec_query_wq;
 184
 185 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 186 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 187 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 188
 189 /* --------------------------------------------------------------------------
 190  *                           Logging/Debugging
 191  * -------------------------------------------------------------------------- */
 192
 193 /*
 194  * Splitters used by the developers to track the boundary of the EC
 195  * handling processes.
 196  */
 197 #ifdef DEBUG
 198 #define EC_DBG_SEP      " "
 199 #define EC_DBG_DRV      "+++++"
 200 #define EC_DBG_STM      "====="
 201 #define EC_DBG_REQ      "*****"
 202 #define EC_DBG_EVT      "#####"
 203 #else
 204 #define EC_DBG_SEP      ""
 205 #define EC_DBG_DRV
 206 #define EC_DBG_STM
 207 #define EC_DBG_REQ
 208 #define EC_DBG_EVT
 209 #endif
 210
 211 #define ec_log_raw(fmt, ...) \
 212         pr_info(fmt "\n", ##__VA_ARGS__)
 213 #define ec_dbg_raw(fmt, ...) \
 214         pr_debug(fmt "\n", ##__VA_ARGS__)
 215 #define ec_log(filter, fmt, ...) \
 216         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 217 #define ec_dbg(filter, fmt, ...) \
 218         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 219
 220 #define ec_log_drv(fmt, ...) \
 221         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 222 #define ec_dbg_drv(fmt, ...) \
 223         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 224 #define ec_dbg_stm(fmt, ...) \
 225         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 226 #define ec_dbg_req(fmt, ...) \
 227         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 228 #define ec_dbg_evt(fmt, ...) \
 229         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 230 #define ec_dbg_ref(ec, fmt, ...) \
 231         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 232
 233 /* --------------------------------------------------------------------------
 234  *                           Device Flags
 235  * -------------------------------------------------------------------------- */
 236
 237 static bool acpi_ec_started(struct acpi_ec *ec)
 238 {
 239         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 240                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 241 }
 242
 243 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 244 {
 245         /*
 246          * There is an OSPM early stage logic. During the early stages
 247          * (boot/resume), OSPMs shouldn't enable the event handling, only
 248          * the EC transactions are allowed to be performed.
 249          */
 250         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 251                 return false;
 252         /*
 253          * However, disabling the event handling is experimental for late
 254          * stage (suspend), and is controlled by the boot parameter of
 255          * "ec_freeze_events":
 256          * 1. true:  The EC event handling is disabled before entering
 257          *           the noirq stage.
 258          * 2. false: The EC event handling is automatically disabled as
 259          *           soon as the EC driver is stopped.
 260          */
 261         if (ec_freeze_events)
 262                 return acpi_ec_started(ec);
 263         else
 264                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 265 }
 266
 267 static bool acpi_ec_flushed(struct acpi_ec *ec)
 268 {
 269         return ec->reference_count == 1;
 270 }
 271
 272 /* --------------------------------------------------------------------------
 273  *                           EC Registers
 274  * -------------------------------------------------------------------------- */
 275
 276 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 277 {
 278         u8 x = inb(ec->command_addr);
 279
 280         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 281                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 282                    x,
 283                    !!(x & ACPI_EC_FLAG_SCI),
 284                    !!(x & ACPI_EC_FLAG_BURST),
 285                    !!(x & ACPI_EC_FLAG_CMD),
 286                    !!(x & ACPI_EC_FLAG_IBF),
 287                    !!(x & ACPI_EC_FLAG_OBF));
 288         return x;
 289 }
 290
 291 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 292 {
 293         u8 x = inb(ec->data_addr);
 294
 295         ec->timestamp = jiffies;
 296         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 297         return x;
 298 }
 299
 300 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 301 {
 302         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 303         outb(command, ec->command_addr);
 304         ec->timestamp = jiffies;
 305 }
 306
 307 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 308 {
 309         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 310         outb(data, ec->data_addr);
 311         ec->timestamp = jiffies;
 312 }
 313
 314 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 315 static const char *acpi_ec_cmd_string(u8 cmd)
 316 {
 317         switch (cmd) {
 318         case 0x80:
 319                 return "RD_EC";
 320         case 0x81:
 321                 return "WR_EC";
 322         case 0x82:
 323                 return "BE_EC";
 324         case 0x83:
 325                 return "BD_EC";
 326         case 0x84:
 327                 return "QR_EC";
 328         }
 329         return "UNKNOWN";
 330 }
 331 #else
 332 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 333 #endif
 334
 335 /* --------------------------------------------------------------------------
 336  *                           GPE Registers
 337  * -------------------------------------------------------------------------- */
 338
 339 static inline bool acpi_ec_is_gpe_raised(struct acpi_ec *ec)
 340 {
 341         acpi_event_status gpe_status = 0;
 342
 343         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 344         return (gpe_status & ACPI_EVENT_FLAG_STATUS_SET) ? true : false;
 345 }
 346
 347 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 348 {
 349         if (open)
 350                 acpi_enable_gpe(NULL, ec->gpe);
 351         else {
 352                 BUG_ON(ec->reference_count < 1);
 353                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 354         }
 355         if (acpi_ec_is_gpe_raised(ec)) {
 356                 /*
 357                  * On some platforms, EN=1 writes cannot trigger GPE. So
 358                  * software need to manually trigger a pseudo GPE event on
 359                  * EN=1 writes.
 360                  */
 361                 ec_dbg_raw("Polling quirk");
 362                 advance_transaction(ec);
 363         }
 364 }
 365
 366 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 367 {
 368         if (close)
 369                 acpi_disable_gpe(NULL, ec->gpe);
 370         else {
 371                 BUG_ON(ec->reference_count < 1);
 372                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 373         }
 374 }
 375
 376 static inline void acpi_ec_clear_gpe(struct acpi_ec *ec)
 377 {
 378         /*
 379          * GPE STS is a W1C register, which means:
 380          * 1. Software can clear it without worrying about clearing other
 381          *    GPEs' STS bits when the hardware sets them in parallel.
 382          * 2. As long as software can ensure only clearing it when it is
 383          *    set, hardware won't set it in parallel.
 384          * So software can clear GPE in any contexts.
 385          * Warning: do not move the check into advance_transaction() as the
 386          * EC commands will be sent without GPE raised.
 387          */
 388         if (!acpi_ec_is_gpe_raised(ec))
 389                 return;
 390         acpi_clear_gpe(NULL, ec->gpe);
 391 }
 392
 393 /* --------------------------------------------------------------------------
 394  *                           Transaction Management
 395  * -------------------------------------------------------------------------- */
 396
 397 static void acpi_ec_submit_request(struct acpi_ec *ec)
 398 {
 399         ec->reference_count++;
 400         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 401             ec->gpe >= 0 && ec->reference_count == 1)
 402                 acpi_ec_enable_gpe(ec, true);
 403 }
 404
 405 static void acpi_ec_complete_request(struct acpi_ec *ec)
 406 {
 407         bool flushed = false;
 408
 409         ec->reference_count--;
 410         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 411             ec->gpe >= 0 && ec->reference_count == 0)
 412                 acpi_ec_disable_gpe(ec, true);
 413         flushed = acpi_ec_flushed(ec);
 414         if (flushed)
 415                 wake_up(&ec->wait);
 416 }
 417
 418 static void acpi_ec_mask_events(struct acpi_ec *ec)
 419 {
 420         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 421                 if (ec->gpe >= 0)
 422                         acpi_ec_disable_gpe(ec, false);
 423                 else
 424                         disable_irq_nosync(ec->irq);
 425
 426                 ec_dbg_drv("Polling enabled");
 427                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 428         }
 429 }
 430
 431 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 432 {
 433         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 434                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 435                 if (ec->gpe >= 0)
 436                         acpi_ec_enable_gpe(ec, false);
 437                 else
 438                         enable_irq(ec->irq);
 439
 440                 ec_dbg_drv("Polling disabled");
 441         }
 442 }
 443
 444 /*
 445  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 446  *                                      the flush operation is not in
 447  *                                      progress
 448  * @ec: the EC device
 449  *
 450  * This function must be used before taking a new action that should hold
 451  * the reference count.  If this function returns false, then the action
 452  * must be discarded or it will prevent the flush operation from being
 453  * completed.
 454  */
 455 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 456 {
 457         if (!acpi_ec_started(ec))
 458                 return false;
 459         acpi_ec_submit_request(ec);
 460         return true;
 461 }
 462
 463 static void acpi_ec_submit_query(struct acpi_ec *ec)
 464 {
 465         acpi_ec_mask_events(ec);
 466         if (!acpi_ec_event_enabled(ec))
 467                 return;
 468         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 469                 ec_dbg_evt("Command(%s) submitted/blocked",
 470                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 471                 ec->nr_pending_queries++;
 472                 ec->events_in_progress++;
 473                 queue_work(ec_wq, &ec->work);
 474         }
 475 }
 476
 477 static void acpi_ec_complete_query(struct acpi_ec *ec)
 478 {
 479         if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 480                 ec_dbg_evt("Command(%s) unblocked",
 481                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 482         acpi_ec_unmask_events(ec);
 483 }
 484
 485 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 486 {
 487         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 488                 ec_log_drv("event unblocked");
 489         /*
 490          * Unconditionally invoke this once after enabling the event
 491          * handling mechanism to detect the pending events.
 492          */
 493         advance_transaction(ec);
 494 }
 495
 496 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 497 {
 498         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 499                 ec_log_drv("event blocked");
 500 }
 501
 502 /*
 503  * Process _Q events that might have accumulated in the EC.
 504  * Run with locked ec mutex.
 505  */
 506 static void acpi_ec_clear(struct acpi_ec *ec)
 507 {
 508         int i, status;
 509         u8 value = 0;
 510
 511         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 512                 status = acpi_ec_query(ec, &value);
 513                 if (status || !value)
 514                         break;
 515         }
 516         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 517                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 518         else
 519                 pr_info("%d stale EC events cleared\n", i);
 520 }
 521
 522 static void acpi_ec_enable_event(struct acpi_ec *ec)
 523 {
 524         unsigned long flags;
 525
 526         spin_lock_irqsave(&ec->lock, flags);
 527         if (acpi_ec_started(ec))
 528                 __acpi_ec_enable_event(ec);
 529         spin_unlock_irqrestore(&ec->lock, flags);
 530
 531         /* Drain additional events if hardware requires that */
 532         if (EC_FLAGS_CLEAR_ON_RESUME)
 533                 acpi_ec_clear(ec);
 534 }
 535
 536 #ifdef CONFIG_PM_SLEEP
 537 static void __acpi_ec_flush_work(void)
 538 {
 539         flush_workqueue(ec_wq); /* flush ec->work */
 540         flush_workqueue(ec_query_wq); /* flush queries */
 541 }
 542
 543 static void acpi_ec_disable_event(struct acpi_ec *ec)
 544 {
 545         unsigned long flags;
 546
 547         spin_lock_irqsave(&ec->lock, flags);
 548         __acpi_ec_disable_event(ec);
 549         spin_unlock_irqrestore(&ec->lock, flags);
 550
 551         /*
 552          * When ec_freeze_events is true, we need to flush events in
 553          * the proper position before entering the noirq stage.
 554          */
 555         __acpi_ec_flush_work();
 556 }
 557
 558 void acpi_ec_flush_work(void)
 559 {
 560         /* Without ec_wq there is nothing to flush. */
 561         if (!ec_wq)
 562                 return;
 563
 564         __acpi_ec_flush_work();
 565 }
 566 #endif /* CONFIG_PM_SLEEP */
 567
 568 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 569 {
 570         bool guarded = true;
 571         unsigned long flags;
 572
 573         spin_lock_irqsave(&ec->lock, flags);
 574         /*
 575          * If firmware SCI_EVT clearing timing is "event", we actually
 576          * don't know when the SCI_EVT will be cleared by firmware after
 577          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 578          * acceptable period.
 579          *
 580          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 581          * flagged, which means SCI_EVT check has just been performed.
 582          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 583          * guarding should have already been performed (via
 584          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 585          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 586          * ACPI_EC_COMMAND_POLL state immediately.
 587          */
 588         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 589             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 590             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 591             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 592                 guarded = false;
 593         spin_unlock_irqrestore(&ec->lock, flags);
 594         return guarded;
 595 }
 596
 597 static int ec_transaction_polled(struct acpi_ec *ec)
 598 {
 599         unsigned long flags;
 600         int ret = 0;
 601
 602         spin_lock_irqsave(&ec->lock, flags);
 603         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 604                 ret = 1;
 605         spin_unlock_irqrestore(&ec->lock, flags);
 606         return ret;
 607 }
 608
 609 static int ec_transaction_completed(struct acpi_ec *ec)
 610 {
 611         unsigned long flags;
 612         int ret = 0;
 613
 614         spin_lock_irqsave(&ec->lock, flags);
 615         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 616                 ret = 1;
 617         spin_unlock_irqrestore(&ec->lock, flags);
 618         return ret;
 619 }
 620
 621 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 622 {
 623         ec->curr->flags |= flag;
 624         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 625                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 626                     flag == ACPI_EC_COMMAND_POLL)
 627                         acpi_ec_complete_query(ec);
 628                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 629                     flag == ACPI_EC_COMMAND_COMPLETE)
 630                         acpi_ec_complete_query(ec);
 631                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 632                     flag == ACPI_EC_COMMAND_COMPLETE)
 633                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 634         }
 635 }
 636
 637 static void advance_transaction(struct acpi_ec *ec)
 638 {
 639         struct transaction *t;
 640         u8 status;
 641         bool wakeup = false;
 642
 643         ec_dbg_stm("%s (%d)", in_interrupt() ? "IRQ" : "TASK",
 644                    smp_processor_id());
 645         /*
 646          * By always clearing STS before handling all indications, we can
 647          * ensure a hardware STS 0->1 change after this clearing can always
 648          * trigger a GPE interrupt.
 649          */
 650         if (ec->gpe >= 0)
 651                 acpi_ec_clear_gpe(ec);
 652
 653         status = acpi_ec_read_status(ec);
 654         t = ec->curr;
 655         /*
 656          * Another IRQ or a guarded polling mode advancement is detected,
 657          * the next QR_EC submission is then allowed.
 658          */
 659         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 660                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 661                     (!ec->nr_pending_queries ||
 662                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 663                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 664                         acpi_ec_complete_query(ec);
 665                 }
 666         }
 667         if (!t)
 668                 goto err;
 669         if (t->flags & ACPI_EC_COMMAND_POLL) {
 670                 if (t->wlen > t->wi) {
 671                         if ((status & ACPI_EC_FLAG_IBF) == 0)
 672                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 673                         else
 674                                 goto err;
 675                 } else if (t->rlen > t->ri) {
 676                         if ((status & ACPI_EC_FLAG_OBF) == 1) {
 677                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 678                                 if (t->rlen == t->ri) {
 679                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 680                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 681                                                 ec_dbg_evt("Command(%s) completed by hardware",
 682                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 683                                         wakeup = true;
 684                                 }
 685                         } else
 686                                 goto err;
 687                 } else if (t->wlen == t->wi &&
 688                            (status & ACPI_EC_FLAG_IBF) == 0) {
 689                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 690                         wakeup = true;
 691                 }
 692                 goto out;
 693         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 694                 acpi_ec_write_cmd(ec, t->command);
 695                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 696                 goto out;
 697         }
 698 err:
 699         /*
 700          * If SCI bit is set, then don't think it's a false IRQ
 701          * otherwise will take a not handled IRQ as a false one.
 702          */
 703         if (!(status & ACPI_EC_FLAG_SCI)) {
 704                 if (in_interrupt() && t) {
 705                         if (t->irq_count < ec_storm_threshold)
 706                                 ++t->irq_count;
 707                         /* Allow triggering on 0 threshold */
 708                         if (t->irq_count == ec_storm_threshold)
 709                                 acpi_ec_mask_events(ec);
 710                 }
 711         }
 712 out:
 713         if (status & ACPI_EC_FLAG_SCI)
 714                 acpi_ec_submit_query(ec);
 715         if (wakeup && in_interrupt())
 716                 wake_up(&ec->wait);
 717 }
 718
 719 static void start_transaction(struct acpi_ec *ec)
 720 {
 721         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 722         ec->curr->flags = 0;
 723 }
 724
 725 static int ec_guard(struct acpi_ec *ec)
 726 {
 727         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 728         unsigned long timeout = ec->timestamp + guard;
 729
 730         /* Ensure guarding period before polling EC status */
 731         do {
 732                 if (ec->busy_polling) {
 733                         /* Perform busy polling */
 734                         if (ec_transaction_completed(ec))
 735                                 return 0;
 736                         udelay(jiffies_to_usecs(guard));
 737                 } else {
 738                         /*
 739                          * Perform wait polling
 740                          * 1. Wait the transaction to be completed by the
 741                          *    GPE handler after the transaction enters
 742                          *    ACPI_EC_COMMAND_POLL state.
 743                          * 2. A special guarding logic is also required
 744                          *    for event clearing mode "event" before the
 745                          *    transaction enters ACPI_EC_COMMAND_POLL
 746                          *    state.
 747                          */
 748                         if (!ec_transaction_polled(ec) &&
 749                             !acpi_ec_guard_event(ec))
 750                                 break;
 751                         if (wait_event_timeout(ec->wait,
 752                                                ec_transaction_completed(ec),
 753                                                guard))
 754                                 return 0;
 755                 }
 756         } while (time_before(jiffies, timeout));
 757         return -ETIME;
 758 }
 759
 760 static int ec_poll(struct acpi_ec *ec)
 761 {
 762         unsigned long flags;
 763         int repeat = 5; /* number of command restarts */
 764
 765         while (repeat--) {
 766                 unsigned long delay = jiffies +
 767                         msecs_to_jiffies(ec_delay);
 768                 do {
 769                         if (!ec_guard(ec))
 770                                 return 0;
 771                         spin_lock_irqsave(&ec->lock, flags);
 772                         advance_transaction(ec);
 773                         spin_unlock_irqrestore(&ec->lock, flags);
 774                 } while (time_before(jiffies, delay));
 775                 pr_debug("controller reset, restart transaction\n");
 776                 spin_lock_irqsave(&ec->lock, flags);
 777                 start_transaction(ec);
 778                 spin_unlock_irqrestore(&ec->lock, flags);
 779         }
 780         return -ETIME;
 781 }
 782
 783 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 784                                         struct transaction *t)
 785 {
 786         unsigned long tmp;
 787         int ret = 0;
 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");
 813 unlock:
 814         spin_unlock_irqrestore(&ec->lock, tmp);
 815         return ret;
 816 }
 817
 818 static 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         if (t->rdata)
 826                 memset(t->rdata, 0, t->rlen);
 827
 828         mutex_lock(&ec->mutex);
 829         if (ec->global_lock) {
 830                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 831                 if (ACPI_FAILURE(status)) {
 832                         status = -ENODEV;
 833                         goto unlock;
 834                 }
 835         }
 836
 837         status = acpi_ec_transaction_unlocked(ec, t);
 838
 839         if (ec->global_lock)
 840                 acpi_release_global_lock(glk);
 841 unlock:
 842         mutex_unlock(&ec->mutex);
 843         return status;
 844 }
 845
 846 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 847 {
 848         u8 d;
 849         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 850                                 .wdata = NULL, .rdata = &d,
 851                                 .wlen = 0, .rlen = 1};
 852
 853         return acpi_ec_transaction(ec, &t);
 854 }
 855
 856 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 857 {
 858         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 859                                 .wdata = NULL, .rdata = NULL,
 860                                 .wlen = 0, .rlen = 0};
 861
 862         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 863                                 acpi_ec_transaction(ec, &t) : 0;
 864 }
 865
 866 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 867 {
 868         int result;
 869         u8 d;
 870         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 871                                 .wdata = &address, .rdata = &d,
 872                                 .wlen = 1, .rlen = 1};
 873
 874         result = acpi_ec_transaction(ec, &t);
 875         *data = d;
 876         return result;
 877 }
 878
 879 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 880 {
 881         u8 wdata[2] = { address, data };
 882         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 883                                 .wdata = wdata, .rdata = NULL,
 884                                 .wlen = 2, .rlen = 0};
 885
 886         return acpi_ec_transaction(ec, &t);
 887 }
 888
 889 int ec_read(u8 addr, u8 *val)
 890 {
 891         int err;
 892         u8 temp_data;
 893
 894         if (!first_ec)
 895                 return -ENODEV;
 896
 897         err = acpi_ec_read(first_ec, addr, &temp_data);
 898
 899         if (!err) {
 900                 *val = temp_data;
 901                 return 0;
 902         }
 903         return err;
 904 }
 905 EXPORT_SYMBOL(ec_read);
 906
 907 int ec_write(u8 addr, u8 val)
 908 {
 909         int err;
 910
 911         if (!first_ec)
 912                 return -ENODEV;
 913
 914         err = acpi_ec_write(first_ec, addr, val);
 915
 916         return err;
 917 }
 918 EXPORT_SYMBOL(ec_write);
 919
 920 int ec_transaction(u8 command,
 921                    const u8 *wdata, unsigned wdata_len,
 922                    u8 *rdata, unsigned rdata_len)
 923 {
 924         struct transaction t = {.command = command,
 925                                 .wdata = wdata, .rdata = rdata,
 926                                 .wlen = wdata_len, .rlen = rdata_len};
 927
 928         if (!first_ec)
 929                 return -ENODEV;
 930
 931         return acpi_ec_transaction(first_ec, &t);
 932 }
 933 EXPORT_SYMBOL(ec_transaction);
 934
 935 /* Get the handle to the EC device */
 936 acpi_handle ec_get_handle(void)
 937 {
 938         if (!first_ec)
 939                 return NULL;
 940         return first_ec->handle;
 941 }
 942 EXPORT_SYMBOL(ec_get_handle);
 943
 944 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 945 {
 946         unsigned long flags;
 947
 948         spin_lock_irqsave(&ec->lock, flags);
 949         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 950                 ec_dbg_drv("Starting EC");
 951                 /* Enable GPE for event processing (SCI_EVT=1) */
 952                 if (!resuming) {
 953                         acpi_ec_submit_request(ec);
 954                         ec_dbg_ref(ec, "Increase driver");
 955                 }
 956                 ec_log_drv("EC started");
 957         }
 958         spin_unlock_irqrestore(&ec->lock, flags);
 959 }
 960
 961 static bool acpi_ec_stopped(struct acpi_ec *ec)
 962 {
 963         unsigned long flags;
 964         bool flushed;
 965
 966         spin_lock_irqsave(&ec->lock, flags);
 967         flushed = acpi_ec_flushed(ec);
 968         spin_unlock_irqrestore(&ec->lock, flags);
 969         return flushed;
 970 }
 971
 972 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 973 {
 974         unsigned long flags;
 975
 976         spin_lock_irqsave(&ec->lock, flags);
 977         if (acpi_ec_started(ec)) {
 978                 ec_dbg_drv("Stopping EC");
 979                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 980                 spin_unlock_irqrestore(&ec->lock, flags);
 981                 wait_event(ec->wait, acpi_ec_stopped(ec));
 982                 spin_lock_irqsave(&ec->lock, flags);
 983                 /* Disable GPE for event processing (SCI_EVT=1) */
 984                 if (!suspending) {
 985                         acpi_ec_complete_request(ec);
 986                         ec_dbg_ref(ec, "Decrease driver");
 987                 } else if (!ec_freeze_events)
 988                         __acpi_ec_disable_event(ec);
 989                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 990                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 991                 ec_log_drv("EC stopped");
 992         }
 993         spin_unlock_irqrestore(&ec->lock, flags);
 994 }
 995
 996 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 997 {
 998         unsigned long flags;
 999
1000         spin_lock_irqsave(&ec->lock, flags);
1001         ec->busy_polling = true;
1002         ec->polling_guard = 0;
1003         ec_log_drv("interrupt blocked");
1004         spin_unlock_irqrestore(&ec->lock, flags);
1005 }
1006
1007 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1008 {
1009         unsigned long flags;
1010
1011         spin_lock_irqsave(&ec->lock, flags);
1012         ec->busy_polling = ec_busy_polling;
1013         ec->polling_guard = ec_polling_guard;
1014         ec_log_drv("interrupt unblocked");
1015         spin_unlock_irqrestore(&ec->lock, flags);
1016 }
1017
1018 void acpi_ec_block_transactions(void)
1019 {
1020         struct acpi_ec *ec = first_ec;
1021
1022         if (!ec)
1023                 return;
1024
1025         mutex_lock(&ec->mutex);
1026         /* Prevent transactions from being carried out */
1027         acpi_ec_stop(ec, true);
1028         mutex_unlock(&ec->mutex);
1029 }
1030
1031 void acpi_ec_unblock_transactions(void)
1032 {
1033         /*
1034          * Allow transactions to happen again (this function is called from
1035          * atomic context during wakeup, so we don't need to acquire the mutex).
1036          */
1037         if (first_ec)
1038                 acpi_ec_start(first_ec, true);
1039 }
1040
1041 /* --------------------------------------------------------------------------
1042                                 Event Management
1043    -------------------------------------------------------------------------- */
1044 static struct acpi_ec_query_handler *
1045 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1046 {
1047         struct acpi_ec_query_handler *handler;
1048
1049         mutex_lock(&ec->mutex);
1050         list_for_each_entry(handler, &ec->list, node) {
1051                 if (value == handler->query_bit) {
1052                         kref_get(&handler->kref);
1053                         mutex_unlock(&ec->mutex);
1054                         return handler;
1055                 }
1056         }
1057         mutex_unlock(&ec->mutex);
1058         return NULL;
1059 }
1060
1061 static void acpi_ec_query_handler_release(struct kref *kref)
1062 {
1063         struct acpi_ec_query_handler *handler =
1064                 container_of(kref, struct acpi_ec_query_handler, kref);
1065
1066         kfree(handler);
1067 }
1068
1069 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1070 {
1071         kref_put(&handler->kref, acpi_ec_query_handler_release);
1072 }
1073
1074 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1075                               acpi_handle handle, acpi_ec_query_func func,
1076                               void *data)
1077 {
1078         struct acpi_ec_query_handler *handler =
1079             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1080
1081         if (!handler)
1082                 return -ENOMEM;
1083
1084         handler->query_bit = query_bit;
1085         handler->handle = handle;
1086         handler->func = func;
1087         handler->data = data;
1088         mutex_lock(&ec->mutex);
1089         kref_init(&handler->kref);
1090         list_add(&handler->node, &ec->list);
1091         mutex_unlock(&ec->mutex);
1092         return 0;
1093 }
1094 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1095
1096 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1097                                           bool remove_all, u8 query_bit)
1098 {
1099         struct acpi_ec_query_handler *handler, *tmp;
1100         LIST_HEAD(free_list);
1101
1102         mutex_lock(&ec->mutex);
1103         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1104                 if (remove_all || query_bit == handler->query_bit) {
1105                         list_del_init(&handler->node);
1106                         list_add(&handler->node, &free_list);
1107                 }
1108         }
1109         mutex_unlock(&ec->mutex);
1110         list_for_each_entry_safe(handler, tmp, &free_list, node)
1111                 acpi_ec_put_query_handler(handler);
1112 }
1113
1114 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1115 {
1116         acpi_ec_remove_query_handlers(ec, false, query_bit);
1117         flush_workqueue(ec_query_wq);
1118 }
1119 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1120
1121 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1122 {
1123         struct acpi_ec_query *q;
1124         struct transaction *t;
1125
1126         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1127         if (!q)
1128                 return NULL;
1129
1130         INIT_WORK(&q->work, acpi_ec_event_processor);
1131         t = &q->transaction;
1132         t->command = ACPI_EC_COMMAND_QUERY;
1133         t->rdata = pval;
1134         t->rlen = 1;
1135         q->ec = ec;
1136         return q;
1137 }
1138
1139 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1140 {
1141         if (q) {
1142                 if (q->handler)
1143                         acpi_ec_put_query_handler(q->handler);
1144                 kfree(q);
1145         }
1146 }
1147
1148 static void acpi_ec_event_processor(struct work_struct *work)
1149 {
1150         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1151         struct acpi_ec_query_handler *handler = q->handler;
1152         struct acpi_ec *ec = q->ec;
1153
1154         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1155
1156         if (handler->func)
1157                 handler->func(handler->data);
1158         else if (handler->handle)
1159                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1160
1161         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1162
1163         spin_lock_irq(&ec->lock);
1164         ec->queries_in_progress--;
1165         spin_unlock_irq(&ec->lock);
1166
1167         acpi_ec_delete_query(q);
1168 }
1169
1170 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1171 {
1172         u8 value = 0;
1173         int result;
1174         struct acpi_ec_query *q;
1175
1176         q = acpi_ec_create_query(ec, &value);
1177         if (!q)
1178                 return -ENOMEM;
1179
1180         /*
1181          * Query the EC to find out which _Qxx method we need to evaluate.
1182          * Note that successful completion of the query causes the ACPI_EC_SCI
1183          * bit to be cleared (and thus clearing the interrupt source).
1184          */
1185         result = acpi_ec_transaction(ec, &q->transaction);
1186         if (!value)
1187                 result = -ENODATA;
1188         if (result)
1189                 goto err_exit;
1190
1191         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1192         if (!q->handler) {
1193                 result = -ENODATA;
1194                 goto err_exit;
1195         }
1196
1197         /*
1198          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1199          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1200          *
1201          * Put this log entry before queue_work() to make it appear in the log
1202          * before any other messages emitted during workqueue handling.
1203          */
1204         ec_dbg_evt("Query(0x%02x) scheduled", value);
1205
1206         spin_lock_irq(&ec->lock);
1207
1208         ec->queries_in_progress++;
1209         queue_work(ec_query_wq, &q->work);
1210
1211         spin_unlock_irq(&ec->lock);
1212
1213 err_exit:
1214         if (result)
1215                 acpi_ec_delete_query(q);
1216         if (data)
1217                 *data = value;
1218         return result;
1219 }
1220
1221 static void acpi_ec_check_event(struct acpi_ec *ec)
1222 {
1223         unsigned long flags;
1224
1225         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1226                 if (ec_guard(ec)) {
1227                         spin_lock_irqsave(&ec->lock, flags);
1228                         /*
1229                          * Take care of the SCI_EVT unless no one else is
1230                          * taking care of it.
1231                          */
1232                         if (!ec->curr)
1233                                 advance_transaction(ec);
1234                         spin_unlock_irqrestore(&ec->lock, flags);
1235                 }
1236         }
1237 }
1238
1239 static void acpi_ec_event_handler(struct work_struct *work)
1240 {
1241         unsigned long flags;
1242         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1243
1244         ec_dbg_evt("Event started");
1245
1246         spin_lock_irqsave(&ec->lock, flags);
1247         while (ec->nr_pending_queries) {
1248                 spin_unlock_irqrestore(&ec->lock, flags);
1249                 (void)acpi_ec_query(ec, NULL);
1250                 spin_lock_irqsave(&ec->lock, flags);
1251                 ec->nr_pending_queries--;
1252                 /*
1253                  * Before exit, make sure that this work item can be
1254                  * scheduled again. There might be QR_EC failures, leaving
1255                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1256                  * item from being scheduled again.
1257                  */
1258                 if (!ec->nr_pending_queries) {
1259                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1260                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1261                                 acpi_ec_complete_query(ec);
1262                 }
1263         }
1264         spin_unlock_irqrestore(&ec->lock, flags);
1265
1266         ec_dbg_evt("Event stopped");
1267
1268         acpi_ec_check_event(ec);
1269
1270         spin_lock_irqsave(&ec->lock, flags);
1271         ec->events_in_progress--;
1272         spin_unlock_irqrestore(&ec->lock, flags);
1273 }
1274
1275 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1276 {
1277         unsigned long flags;
1278
1279         spin_lock_irqsave(&ec->lock, flags);
1280         advance_transaction(ec);
1281         spin_unlock_irqrestore(&ec->lock, flags);
1282 }
1283
1284 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1285                                u32 gpe_number, void *data)
1286 {
1287         acpi_ec_handle_interrupt(data);
1288         return ACPI_INTERRUPT_HANDLED;
1289 }
1290
1291 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1292 {
1293         acpi_ec_handle_interrupt(data);
1294         return IRQ_HANDLED;
1295 }
1296
1297 /* --------------------------------------------------------------------------
1298  *                           Address Space Management
1299  * -------------------------------------------------------------------------- */
1300
1301 static acpi_status
1302 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1303                       u32 bits, u64 *value64,
1304                       void *handler_context, void *region_context)
1305 {
1306         struct acpi_ec *ec = handler_context;
1307         int result = 0, i, bytes = bits / 8;
1308         u8 *value = (u8 *)value64;
1309
1310         if ((address > 0xFF) || !value || !handler_context)
1311                 return AE_BAD_PARAMETER;
1312
1313         if (function != ACPI_READ && function != ACPI_WRITE)
1314                 return AE_BAD_PARAMETER;
1315
1316         if (ec->busy_polling || bits > 8)
1317                 acpi_ec_burst_enable(ec);
1318
1319         for (i = 0; i < bytes; ++i, ++address, ++value)
1320                 result = (function == ACPI_READ) ?
1321                         acpi_ec_read(ec, address, value) :
1322                         acpi_ec_write(ec, address, *value);
1323
1324         if (ec->busy_polling || bits > 8)
1325                 acpi_ec_burst_disable(ec);
1326
1327         switch (result) {
1328         case -EINVAL:
1329                 return AE_BAD_PARAMETER;
1330         case -ENODEV:
1331                 return AE_NOT_FOUND;
1332         case -ETIME:
1333                 return AE_TIME;
1334         default:
1335                 return AE_OK;
1336         }
1337 }
1338
1339 /* --------------------------------------------------------------------------
1340  *                             Driver Interface
1341  * -------------------------------------------------------------------------- */
1342
1343 static acpi_status
1344 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1345
1346 static void acpi_ec_free(struct acpi_ec *ec)
1347 {
1348         if (first_ec == ec)
1349                 first_ec = NULL;
1350         if (boot_ec == ec)
1351                 boot_ec = NULL;
1352         kfree(ec);
1353 }
1354
1355 static struct acpi_ec *acpi_ec_alloc(void)
1356 {
1357         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1358
1359         if (!ec)
1360                 return NULL;
1361         mutex_init(&ec->mutex);
1362         init_waitqueue_head(&ec->wait);
1363         INIT_LIST_HEAD(&ec->list);
1364         spin_lock_init(&ec->lock);
1365         INIT_WORK(&ec->work, acpi_ec_event_handler);
1366         ec->timestamp = jiffies;
1367         ec->busy_polling = true;
1368         ec->polling_guard = 0;
1369         ec->gpe = -1;
1370         ec->irq = -1;
1371         return ec;
1372 }
1373
1374 static acpi_status
1375 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1376                                void *context, void **return_value)
1377 {
1378         char node_name[5];
1379         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1380         struct acpi_ec *ec = context;
1381         int value = 0;
1382         acpi_status status;
1383
1384         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1385
1386         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1387                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1388         return AE_OK;
1389 }
1390
1391 static acpi_status
1392 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1393 {
1394         acpi_status status;
1395         unsigned long long tmp = 0;
1396         struct acpi_ec *ec = context;
1397
1398         /* clear addr values, ec_parse_io_ports depend on it */
1399         ec->command_addr = ec->data_addr = 0;
1400
1401         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1402                                      ec_parse_io_ports, ec);
1403         if (ACPI_FAILURE(status))
1404                 return status;
1405         if (ec->data_addr == 0 || ec->command_addr == 0)
1406                 return AE_OK;
1407
1408         /* Get GPE bit assignment (EC events). */
1409         /* TODO: Add support for _GPE returning a package */
1410         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1411         if (ACPI_SUCCESS(status))
1412                 ec->gpe = tmp;
1413         /*
1414          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1415          * platforms which use GpioInt instead of GPE.
1416          */
1417
1418         /* Use the global lock for all EC transactions? */
1419         tmp = 0;
1420         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1421         ec->global_lock = tmp;
1422         ec->handle = handle;
1423         return AE_CTRL_TERMINATE;
1424 }
1425
1426 static bool install_gpe_event_handler(struct acpi_ec *ec)
1427 {
1428         acpi_status status;
1429
1430         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1431                                               ACPI_GPE_EDGE_TRIGGERED,
1432                                               &acpi_ec_gpe_handler, ec);
1433         if (ACPI_FAILURE(status))
1434                 return false;
1435
1436         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1437                 acpi_ec_enable_gpe(ec, true);
1438
1439         return true;
1440 }
1441
1442 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1443 {
1444         return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1445                            "ACPI EC", ec) >= 0;
1446 }
1447
1448 /**
1449  * ec_install_handlers - Install service callbacks and register query methods.
1450  * @ec: Target EC.
1451  * @device: ACPI device object corresponding to @ec.
1452  *
1453  * Install a handler for the EC address space type unless it has been installed
1454  * already.  If @device is not NULL, also look for EC query methods in the
1455  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1456  * handler for the EC, if possible.
1457  *
1458  * Return:
1459  * -ENODEV if the address space handler cannot be installed, which means
1460  *  "unable to handle transactions",
1461  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1462  * or 0 (success) otherwise.
1463  */
1464 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1465 {
1466         acpi_status status;
1467
1468         acpi_ec_start(ec, false);
1469
1470         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1471                 acpi_ec_enter_noirq(ec);
1472                 status = acpi_install_address_space_handler(ec->handle,
1473                                                             ACPI_ADR_SPACE_EC,
1474                                                             &acpi_ec_space_handler,
1475                                                             NULL, ec);
1476                 if (ACPI_FAILURE(status)) {
1477                         acpi_ec_stop(ec, false);
1478                         return -ENODEV;
1479                 }
1480                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1481         }
1482
1483         if (!device)
1484                 return 0;
1485
1486         if (ec->gpe < 0) {
1487                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1488                 int irq = acpi_dev_gpio_irq_get(device, 0);
1489                 /*
1490                  * Bail out right away for deferred probing or complete the
1491                  * initialization regardless of any other errors.
1492                  */
1493                 if (irq == -EPROBE_DEFER)
1494                         return -EPROBE_DEFER;
1495                 else if (irq >= 0)
1496                         ec->irq = irq;
1497         }
1498
1499         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1500                 /* Find and register all query methods */
1501                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1502                                     acpi_ec_register_query_methods,
1503                                     NULL, ec, NULL);
1504                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1505         }
1506         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1507                 bool ready = false;
1508
1509                 if (ec->gpe >= 0)
1510                         ready = install_gpe_event_handler(ec);
1511                 else if (ec->irq >= 0)
1512                         ready = install_gpio_irq_event_handler(ec);
1513
1514                 if (ready) {
1515                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1516                         acpi_ec_leave_noirq(ec);
1517                 }
1518                 /*
1519                  * Failures to install an event handler are not fatal, because
1520                  * the EC can be polled for events.
1521                  */
1522         }
1523         /* EC is fully operational, allow queries */
1524         acpi_ec_enable_event(ec);
1525
1526         return 0;
1527 }
1528
1529 static void ec_remove_handlers(struct acpi_ec *ec)
1530 {
1531         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1532                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1533                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1534                         pr_err("failed to remove space handler\n");
1535                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1536         }
1537
1538         /*
1539          * Stops handling the EC transactions after removing the operation
1540          * region handler. This is required because _REG(DISCONNECT)
1541          * invoked during the removal can result in new EC transactions.
1542          *
1543          * Flushes the EC requests and thus disables the GPE before
1544          * removing the GPE handler. This is required by the current ACPICA
1545          * GPE core. ACPICA GPE core will automatically disable a GPE when
1546          * it is indicated but there is no way to handle it. So the drivers
1547          * must disable the GPEs prior to removing the GPE handlers.
1548          */
1549         acpi_ec_stop(ec, false);
1550
1551         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1552                 if (ec->gpe >= 0 &&
1553                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1554                                  &acpi_ec_gpe_handler)))
1555                         pr_err("failed to remove gpe handler\n");
1556
1557                 if (ec->irq >= 0)
1558                         free_irq(ec->irq, ec);
1559
1560                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1561         }
1562         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1563                 acpi_ec_remove_query_handlers(ec, true, 0);
1564                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1565         }
1566 }
1567
1568 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1569 {
1570         int ret;
1571
1572         ret = ec_install_handlers(ec, device);
1573         if (ret)
1574                 return ret;
1575
1576         /* First EC capable of handling transactions */
1577         if (!first_ec)
1578                 first_ec = ec;
1579
1580         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1581                 ec->data_addr);
1582
1583         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1584                 if (ec->gpe >= 0)
1585                         pr_info("GPE=0x%x\n", ec->gpe);
1586                 else
1587                         pr_info("IRQ=%d\n", ec->irq);
1588         }
1589
1590         return ret;
1591 }
1592
1593 static int acpi_ec_add(struct acpi_device *device)
1594 {
1595         struct acpi_ec *ec;
1596         int ret;
1597
1598         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1599         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1600
1601         if (boot_ec && (boot_ec->handle == device->handle ||
1602             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1603                 /* Fast path: this device corresponds to the boot EC. */
1604                 ec = boot_ec;
1605         } else {
1606                 acpi_status status;
1607
1608                 ec = acpi_ec_alloc();
1609                 if (!ec)
1610                         return -ENOMEM;
1611
1612                 status = ec_parse_device(device->handle, 0, ec, NULL);
1613                 if (status != AE_CTRL_TERMINATE) {
1614                         ret = -EINVAL;
1615                         goto err;
1616                 }
1617
1618                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1619                     ec->data_addr == boot_ec->data_addr &&
1620                     !EC_FLAGS_TRUST_DSDT_GPE) {
1621                         /*
1622                          * Trust PNP0C09 namespace location rather than
1623                          * ECDT ID. But trust ECDT GPE rather than _GPE
1624                          * because of ASUS quirks, so do not change
1625                          * boot_ec->gpe to ec->gpe.
1626                          */
1627                         boot_ec->handle = ec->handle;
1628                         acpi_handle_debug(ec->handle, "duplicated.\n");
1629                         acpi_ec_free(ec);
1630                         ec = boot_ec;
1631                 }
1632         }
1633
1634         ret = acpi_ec_setup(ec, device);
1635         if (ret)
1636                 goto err;
1637
1638         if (ec == boot_ec)
1639                 acpi_handle_info(boot_ec->handle,
1640                                  "Boot %s EC initialization complete\n",
1641                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1642
1643         acpi_handle_info(ec->handle,
1644                          "EC: Used to handle transactions and events\n");
1645
1646         device->driver_data = ec;
1647
1648         ret = !!request_region(ec->data_addr, 1, "EC data");
1649         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1650         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1651         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1652
1653         /* Reprobe devices depending on the EC */
1654         acpi_walk_dep_device_list(ec->handle);
1655
1656         acpi_handle_debug(ec->handle, "enumerated.\n");
1657         return 0;
1658
1659 err:
1660         if (ec != boot_ec)
1661                 acpi_ec_free(ec);
1662
1663         return ret;
1664 }
1665
1666 static int acpi_ec_remove(struct acpi_device *device)
1667 {
1668         struct acpi_ec *ec;
1669
1670         if (!device)
1671                 return -EINVAL;
1672
1673         ec = acpi_driver_data(device);
1674         release_region(ec->data_addr, 1);
1675         release_region(ec->command_addr, 1);
1676         device->driver_data = NULL;
1677         if (ec != boot_ec) {
1678                 ec_remove_handlers(ec);
1679                 acpi_ec_free(ec);
1680         }
1681         return 0;
1682 }
1683
1684 static acpi_status
1685 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1686 {
1687         struct acpi_ec *ec = context;
1688
1689         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1690                 return AE_OK;
1691
1692         /*
1693          * The first address region returned is the data port, and
1694          * the second address region returned is the status/command
1695          * port.
1696          */
1697         if (ec->data_addr == 0)
1698                 ec->data_addr = resource->data.io.minimum;
1699         else if (ec->command_addr == 0)
1700                 ec->command_addr = resource->data.io.minimum;
1701         else
1702                 return AE_CTRL_TERMINATE;
1703
1704         return AE_OK;
1705 }
1706
1707 static const struct acpi_device_id ec_device_ids[] = {
1708         {"PNP0C09", 0},
1709         {ACPI_ECDT_HID, 0},
1710         {"", 0},
1711 };
1712
1713 /*
1714  * This function is not Windows-compatible as Windows never enumerates the
1715  * namespace EC before the main ACPI device enumeration process. It is
1716  * retained for historical reason and will be deprecated in the future.
1717  */
1718 void __init acpi_ec_dsdt_probe(void)
1719 {
1720         struct acpi_ec *ec;
1721         acpi_status status;
1722         int ret;
1723
1724         /*
1725          * If a platform has ECDT, there is no need to proceed as the
1726          * following probe is not a part of the ACPI device enumeration,
1727          * executing _STA is not safe, and thus this probe may risk of
1728          * picking up an invalid EC device.
1729          */
1730         if (boot_ec)
1731                 return;
1732
1733         ec = acpi_ec_alloc();
1734         if (!ec)
1735                 return;
1736
1737         /*
1738          * At this point, the namespace is initialized, so start to find
1739          * the namespace objects.
1740          */
1741         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1742         if (ACPI_FAILURE(status) || !ec->handle) {
1743                 acpi_ec_free(ec);
1744                 return;
1745         }
1746
1747         /*
1748          * When the DSDT EC is available, always re-configure boot EC to
1749          * have _REG evaluated. _REG can only be evaluated after the
1750          * namespace initialization.
1751          * At this point, the GPE is not fully initialized, so do not to
1752          * handle the events.
1753          */
1754         ret = acpi_ec_setup(ec, NULL);
1755         if (ret) {
1756                 acpi_ec_free(ec);
1757                 return;
1758         }
1759
1760         boot_ec = ec;
1761
1762         acpi_handle_info(ec->handle,
1763                          "Boot DSDT EC used to handle transactions\n");
1764 }
1765
1766 /*
1767  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1768  *
1769  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1770  * found a matching object in the namespace.
1771  *
1772  * Next, in case the DSDT EC is not functioning, it is still necessary to
1773  * provide a functional ECDT EC to handle events, so add an extra device object
1774  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1775  *
1776  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1777  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1778  */
1779 static void __init acpi_ec_ecdt_start(void)
1780 {
1781         struct acpi_table_ecdt *ecdt_ptr;
1782         acpi_handle handle;
1783         acpi_status status;
1784
1785         /* Bail out if a matching EC has been found in the namespace. */
1786         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1787                 return;
1788
1789         /* Look up the object pointed to from the ECDT in the namespace. */
1790         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1791                                 (struct acpi_table_header **)&ecdt_ptr);
1792         if (ACPI_FAILURE(status))
1793                 return;
1794
1795         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1796         if (ACPI_SUCCESS(status)) {
1797                 boot_ec->handle = handle;
1798
1799                 /* Add a special ACPI device object to represent the boot EC. */
1800                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1801         }
1802
1803         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1804 }
1805
1806 /*
1807  * On some hardware it is necessary to clear events accumulated by the EC during
1808  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1809  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1810  *
1811  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1812  *
1813  * Ideally, the EC should also be instructed NOT to accumulate events during
1814  * sleep (which Windows seems to do somehow), but the interface to control this
1815  * behaviour is not known at this time.
1816  *
1817  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1818  * however it is very likely that other Samsung models are affected.
1819  *
1820  * On systems which don't accumulate _Q events during sleep, this extra check
1821  * should be harmless.
1822  */
1823 static int ec_clear_on_resume(const struct dmi_system_id *id)
1824 {
1825         pr_debug("Detected system needing EC poll on resume.\n");
1826         EC_FLAGS_CLEAR_ON_RESUME = 1;
1827         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1828         return 0;
1829 }
1830
1831 /*
1832  * Some ECDTs contain wrong register addresses.
1833  * MSI MS-171F
1834  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1835  */
1836 static int ec_correct_ecdt(const struct dmi_system_id *id)
1837 {
1838         pr_debug("Detected system needing ECDT address correction.\n");
1839         EC_FLAGS_CORRECT_ECDT = 1;
1840         return 0;
1841 }
1842
1843 /*
1844  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1845  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1846  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1847  */
1848 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1849 {
1850         pr_debug("Detected system needing DSDT GPE setting.\n");
1851         EC_FLAGS_TRUST_DSDT_GPE = 1;
1852         return 0;
1853 }
1854
1855 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1856         {
1857         ec_correct_ecdt, "MSI MS-171F", {
1858         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1859         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1860         {
1861         /* https://bugzilla.kernel.org/show_bug.cgi?id=209989 */
1862         ec_honor_dsdt_gpe, "HP Pavilion Gaming Laptop 15-cx0xxx", {
1863         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1864         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),}, NULL},
1865         {
1866         ec_clear_on_resume, "Samsung hardware", {
1867         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1868         {},
1869 };
1870
1871 void __init acpi_ec_ecdt_probe(void)
1872 {
1873         struct acpi_table_ecdt *ecdt_ptr;
1874         struct acpi_ec *ec;
1875         acpi_status status;
1876         int ret;
1877
1878         /* Generate a boot ec context. */
1879         dmi_check_system(ec_dmi_table);
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         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1886                 /*
1887                  * Asus X50GL:
1888                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1889                  */
1890                 goto out;
1891         }
1892
1893         ec = acpi_ec_alloc();
1894         if (!ec)
1895                 goto out;
1896
1897         if (EC_FLAGS_CORRECT_ECDT) {
1898                 ec->command_addr = ecdt_ptr->data.address;
1899                 ec->data_addr = ecdt_ptr->control.address;
1900         } else {
1901                 ec->command_addr = ecdt_ptr->control.address;
1902                 ec->data_addr = ecdt_ptr->data.address;
1903         }
1904
1905         /*
1906          * Ignore the GPE value on Reduced Hardware platforms.
1907          * Some products have this set to an erroneous value.
1908          */
1909         if (!acpi_gbl_reduced_hardware)
1910                 ec->gpe = ecdt_ptr->gpe;
1911
1912         ec->handle = ACPI_ROOT_OBJECT;
1913
1914         /*
1915          * At this point, the namespace is not initialized, so do not find
1916          * the namespace objects, or handle the events.
1917          */
1918         ret = acpi_ec_setup(ec, NULL);
1919         if (ret) {
1920                 acpi_ec_free(ec);
1921                 goto out;
1922         }
1923
1924         boot_ec = ec;
1925         boot_ec_is_ecdt = true;
1926
1927         pr_info("Boot ECDT EC used to handle transactions\n");
1928
1929 out:
1930         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1931 }
1932
1933 #ifdef CONFIG_PM_SLEEP
1934 static int acpi_ec_suspend(struct device *dev)
1935 {
1936         struct acpi_ec *ec =
1937                 acpi_driver_data(to_acpi_device(dev));
1938
1939         if (!pm_suspend_no_platform() && ec_freeze_events)
1940                 acpi_ec_disable_event(ec);
1941         return 0;
1942 }
1943
1944 static int acpi_ec_suspend_noirq(struct device *dev)
1945 {
1946         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1947
1948         /*
1949          * The SCI handler doesn't run at this point, so the GPE can be
1950          * masked at the low level without side effects.
1951          */
1952         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1953             ec->gpe >= 0 && ec->reference_count >= 1)
1954                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1955
1956         acpi_ec_enter_noirq(ec);
1957
1958         return 0;
1959 }
1960
1961 static int acpi_ec_resume_noirq(struct device *dev)
1962 {
1963         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1964
1965         acpi_ec_leave_noirq(ec);
1966
1967         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1968             ec->gpe >= 0 && ec->reference_count >= 1)
1969                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1970
1971         return 0;
1972 }
1973
1974 static int acpi_ec_resume(struct device *dev)
1975 {
1976         struct acpi_ec *ec =
1977                 acpi_driver_data(to_acpi_device(dev));
1978
1979         acpi_ec_enable_event(ec);
1980         return 0;
1981 }
1982
1983 void acpi_ec_mark_gpe_for_wake(void)
1984 {
1985         if (first_ec && !ec_no_wakeup)
1986                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1987 }
1988 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1989
1990 void acpi_ec_set_gpe_wake_mask(u8 action)
1991 {
1992         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1993                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1994 }
1995
1996 bool acpi_ec_dispatch_gpe(void)
1997 {
1998         bool work_in_progress;
1999         u32 ret;
2000
2001         if (!first_ec)
2002                 return acpi_any_gpe_status_set(U32_MAX);
2003
2004         /*
2005          * Report wakeup if the status bit is set for any enabled GPE other
2006          * than the EC one.
2007          */
2008         if (acpi_any_gpe_status_set(first_ec->gpe))
2009                 return true;
2010
2011         /*
2012          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2013          * to allow the caller to process events properly after that.
2014          */
2015         ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2016         if (ret == ACPI_INTERRUPT_HANDLED)
2017                 pm_pr_dbg("ACPI EC GPE dispatched\n");
2018
2019         /* Drain EC work. */
2020         do {
2021                 acpi_ec_flush_work();
2022
2023                 pm_pr_dbg("ACPI EC work flushed\n");
2024
2025                 spin_lock_irq(&first_ec->lock);
2026
2027                 work_in_progress = first_ec->events_in_progress +
2028                         first_ec->queries_in_progress > 0;
2029
2030                 spin_unlock_irq(&first_ec->lock);
2031         } while (work_in_progress && !pm_wakeup_pending());
2032
2033         return false;
2034 }
2035 #endif /* CONFIG_PM_SLEEP */
2036
2037 static const struct dev_pm_ops acpi_ec_pm = {
2038         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2039         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2040 };
2041
2042 static int param_set_event_clearing(const char *val,
2043                                     const struct kernel_param *kp)
2044 {
2045         int result = 0;
2046
2047         if (!strncmp(val, "status", sizeof("status") - 1)) {
2048                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2049                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2050         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2051                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2052                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2053         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2054                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2055                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2056         } else
2057                 result = -EINVAL;
2058         return result;
2059 }
2060
2061 static int param_get_event_clearing(char *buffer,
2062                                     const struct kernel_param *kp)
2063 {
2064         switch (ec_event_clearing) {
2065         case ACPI_EC_EVT_TIMING_STATUS:
2066                 return sprintf(buffer, "status\n");
2067         case ACPI_EC_EVT_TIMING_QUERY:
2068                 return sprintf(buffer, "query\n");
2069         case ACPI_EC_EVT_TIMING_EVENT:
2070                 return sprintf(buffer, "event\n");
2071         default:
2072                 return sprintf(buffer, "invalid\n");
2073         }
2074         return 0;
2075 }
2076
2077 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2078                   NULL, 0644);
2079 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2080
2081 static struct acpi_driver acpi_ec_driver = {
2082         .name = "ec",
2083         .class = ACPI_EC_CLASS,
2084         .ids = ec_device_ids,
2085         .ops = {
2086                 .add = acpi_ec_add,
2087                 .remove = acpi_ec_remove,
2088                 },
2089         .drv.pm = &acpi_ec_pm,
2090 };
2091
2092 static void acpi_ec_destroy_workqueues(void)
2093 {
2094         if (ec_wq) {
2095                 destroy_workqueue(ec_wq);
2096                 ec_wq = NULL;
2097         }
2098         if (ec_query_wq) {
2099                 destroy_workqueue(ec_query_wq);
2100                 ec_query_wq = NULL;
2101         }
2102 }
2103
2104 static int acpi_ec_init_workqueues(void)
2105 {
2106         if (!ec_wq)
2107                 ec_wq = alloc_ordered_workqueue("kec", 0);
2108
2109         if (!ec_query_wq)
2110                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2111
2112         if (!ec_wq || !ec_query_wq) {
2113                 acpi_ec_destroy_workqueues();
2114                 return -ENODEV;
2115         }
2116         return 0;
2117 }
2118
2119 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2120         {
2121                 .ident = "Thinkpad X1 Carbon 6th",
2122                 .matches = {
2123                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2124                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2125                 },
2126         },
2127         {
2128                 .ident = "ThinkPad X1 Yoga 3rd",
2129                 .matches = {
2130                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2131                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2132                 },
2133         },
2134         { },
2135 };
2136
2137 void __init acpi_ec_init(void)
2138 {
2139         int result;
2140
2141         result = acpi_ec_init_workqueues();
2142         if (result)
2143                 return;
2144
2145         /*
2146          * Disable EC wakeup on following systems to prevent periodic
2147          * wakeup from EC GPE.
2148          */
2149         if (dmi_check_system(acpi_ec_no_wakeup)) {
2150                 ec_no_wakeup = true;
2151                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2152         }
2153
2154         /* Driver must be registered after acpi_ec_init_workqueues(). */
2155         acpi_bus_register_driver(&acpi_ec_driver);
2156
2157         acpi_ec_ecdt_start();
2158 }
2159
2160 /* EC driver currently not unloadable */
2161 #if 0
2162 static void __exit acpi_ec_exit(void)
2163 {
2164
2165         acpi_bus_unregister_driver(&acpi_ec_driver);
2166         acpi_ec_destroy_workqueues();
2167 }
2168 #endif  /* 0 */