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 <[email protected]>
   7  *            2006, 2007 Alexey Starikovskiy <[email protected]>
   8  *            2006       Denis Sadykov <[email protected]>
   9  *            2004       Luming Yu <[email protected]>
  10  *            2001, 2002 Andy Grover <[email protected]>
  11  *            2001, 2002 Paul Diefenbaugh <[email protected]>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <[email protected]>
  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_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 */
 108 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 109 module_param(ec_delay, uint, 0644);
 110 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 111
 112 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 113 module_param(ec_max_queries, uint, 0644);
 114 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 115
 116 static bool ec_busy_polling __read_mostly;
 117 module_param(ec_busy_polling, bool, 0644);
 118 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 119
 120 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 121 module_param(ec_polling_guard, uint, 0644);
 122 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 123
 124 static 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  */
 131 static unsigned int ec_storm_threshold  __read_mostly = 8;
 132 module_param(ec_storm_threshold, uint, 0644);
 133 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 134
 135 static bool ec_freeze_events __read_mostly;
 136 module_param(ec_freeze_events, bool, 0644);
 137 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 138
 139 static bool ec_no_wakeup __read_mostly;
 140 module_param(ec_no_wakeup, bool, 0644);
 141 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 142
 143 struct 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
 152 struct 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
 164 struct 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
 171 static int acpi_ec_submit_query(struct acpi_ec *ec);
 172 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 173 static void acpi_ec_event_handler(struct work_struct *work);
 174
 175 struct acpi_ec *first_ec;
 176 EXPORT_SYMBOL(first_ec);
 177
 178 static struct acpi_ec *boot_ec;
 179 static bool boot_ec_is_ecdt;
 180 static struct workqueue_struct *ec_wq;
 181 static struct workqueue_struct *ec_query_wq;
 182
 183 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 184 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 185 static 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
 235 static 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
 241 static 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
 265 static bool acpi_ec_flushed(struct acpi_ec *ec)
 266 {
 267         return ec->reference_count == 1;
 268 }
 269
 270 /* --------------------------------------------------------------------------
 271  *                           EC Registers
 272  * -------------------------------------------------------------------------- */
 273
 274 static 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
 289 static 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
 298 static 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
 305 static 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)
 313 static 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
 337 static 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
 345 static 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
 364 static 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
 378 static 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
 386 static 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
 399 static 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
 412 static 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  */
 436 static 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
 444 static 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
 475 static 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
 481 static 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
 491 static 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
 502 static 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  */
 512 static 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
 526 static 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
 541 static 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
 547 static 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
 562 void 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
 572 static 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
 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
 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
 647 static 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
 657 static 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
 708 out:
 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
 716 static 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
 722 static 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
 757 static 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
 780 static 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");
 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
 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);
 839 unlock:
 840         mutex_unlock(&ec->mutex);
 841         return status;
 842 }
 843
 844 static 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
 854 static 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
 864 static 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
 877 static 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
 890 static 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
 900 static 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
 910 int 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 }
 926 EXPORT_SYMBOL(ec_read);
 927
 928 int 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 }
 935 EXPORT_SYMBOL(ec_write);
 936
 937 int 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 }
 950 EXPORT_SYMBOL(ec_transaction);
 951
 952 /* Get the handle to the EC device */
 953 acpi_handle ec_get_handle(void)
 954 {
 955         if (!first_ec)
 956                 return NULL;
 957         return first_ec->handle;
 958 }
 959 EXPORT_SYMBOL(ec_get_handle);
 960
 961 static 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
 978 static 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
 989 static 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
1013 static 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
1024 static 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
1035 void 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
1048 void 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    -------------------------------------------------------------------------- */
1061 static struct acpi_ec_query_handler *
1062 acpi_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
1078 static 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
1086 static 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
1091 int 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 }
1115 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1116
1117 static 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
1142 void 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 }
1147 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1148
1149 static 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
1172 static 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
1190 static 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
1238 err_exit:
1239         kfree(q);
1240
1241         return result;
1242 }
1243
1244 static 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
1294 static 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
1314 static 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
1325 static 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
1332 static 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
1342 static acpi_status
1343 acpi_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
1387 unlock:
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
1408 static acpi_status
1409 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1410
1411 static 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
1420 static 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
1439 static acpi_status
1440 acpi_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
1456 static acpi_status
1457 ec_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
1491 static 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
1507 static 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  */
1530 static 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
1603 static 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
1646 static 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
1675 static 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
1744 err:
1745         if (ec != boot_ec)
1746                 acpi_ec_free(ec);
1747
1748         return ret;
1749 }
1750
1751 static 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
1768 void 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
1774 static acpi_status
1775 ec_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
1797 static 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  */
1808 void __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  */
1869 static 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  */
1913 static 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  */
1926 static 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  */
1938 static 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
1945 static 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
2012 void __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
2070 out:
2071         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2072 }
2073
2074 #ifdef CONFIG_PM_SLEEP
2075 static 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
2085 static 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
2102 static 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
2115 static 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
2124 void 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 }
2129 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2130
2131 void 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
2137 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2138 {
2139         return ec->events_in_progress + ec->queries_in_progress > 0;
2140 }
2141
2142 bool 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
2203 static 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
2208 static 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
2227 static 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
2243 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2244                   NULL, 0644);
2245 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2246
2247 static 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
2258 static 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
2270 static 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
2285 static 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
2307 void __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
2332 static 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 */