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_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
  98         EC_FLAGS_STARTED,               /* Driver is started */
  99         EC_FLAGS_STOPPED,               /* Driver is stopped */
 100         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 101 };
 102
 103 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 104 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 105
 106 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 107 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 108 module_param(ec_delay, uint, 0644);
 109 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 110
 111 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 112 module_param(ec_max_queries, uint, 0644);
 113 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 114
 115 static bool ec_busy_polling __read_mostly;
 116 module_param(ec_busy_polling, bool, 0644);
 117 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 118
 119 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 120 module_param(ec_polling_guard, uint, 0644);
 121 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 122
 123 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 124
 125 /*
 126  * If the number of false interrupts per one transaction exceeds
 127  * this threshold, will think there is a GPE storm happened and
 128  * will disable the GPE for normal transaction.
 129  */
 130 static unsigned int ec_storm_threshold  __read_mostly = 8;
 131 module_param(ec_storm_threshold, uint, 0644);
 132 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 133
 134 static bool ec_freeze_events __read_mostly;
 135 module_param(ec_freeze_events, bool, 0644);
 136 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 137
 138 static bool ec_no_wakeup __read_mostly;
 139 module_param(ec_no_wakeup, bool, 0644);
 140 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 141
 142 struct acpi_ec_query_handler {
 143         struct list_head node;
 144         acpi_ec_query_func func;
 145         acpi_handle handle;
 146         void *data;
 147         u8 query_bit;
 148         struct kref kref;
 149 };
 150
 151 struct transaction {
 152         const u8 *wdata;
 153         u8 *rdata;
 154         unsigned short irq_count;
 155         u8 command;
 156         u8 wi;
 157         u8 ri;
 158         u8 wlen;
 159         u8 rlen;
 160         u8 flags;
 161 };
 162
 163 struct acpi_ec_query {
 164         struct transaction transaction;
 165         struct work_struct work;
 166         struct acpi_ec_query_handler *handler;
 167         struct acpi_ec *ec;
 168 };
 169
 170 static int acpi_ec_submit_query(struct acpi_ec *ec);
 171 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 172 static void acpi_ec_event_handler(struct work_struct *work);
 173
 174 struct acpi_ec *first_ec;
 175 EXPORT_SYMBOL(first_ec);
 176
 177 static struct acpi_ec *boot_ec;
 178 static bool boot_ec_is_ecdt;
 179 static struct workqueue_struct *ec_wq;
 180 static struct workqueue_struct *ec_query_wq;
 181
 182 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 183 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 184 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 185
 186 /* --------------------------------------------------------------------------
 187  *                           Logging/Debugging
 188  * -------------------------------------------------------------------------- */
 189
 190 /*
 191  * Splitters used by the developers to track the boundary of the EC
 192  * handling processes.
 193  */
 194 #ifdef DEBUG
 195 #define EC_DBG_SEP      " "
 196 #define EC_DBG_DRV      "+++++"
 197 #define EC_DBG_STM      "====="
 198 #define EC_DBG_REQ      "*****"
 199 #define EC_DBG_EVT      "#####"
 200 #else
 201 #define EC_DBG_SEP      ""
 202 #define EC_DBG_DRV
 203 #define EC_DBG_STM
 204 #define EC_DBG_REQ
 205 #define EC_DBG_EVT
 206 #endif
 207
 208 #define ec_log_raw(fmt, ...) \
 209         pr_info(fmt "\n", ##__VA_ARGS__)
 210 #define ec_dbg_raw(fmt, ...) \
 211         pr_debug(fmt "\n", ##__VA_ARGS__)
 212 #define ec_log(filter, fmt, ...) \
 213         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 214 #define ec_dbg(filter, fmt, ...) \
 215         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 216
 217 #define ec_log_drv(fmt, ...) \
 218         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 219 #define ec_dbg_drv(fmt, ...) \
 220         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 221 #define ec_dbg_stm(fmt, ...) \
 222         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 223 #define ec_dbg_req(fmt, ...) \
 224         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 225 #define ec_dbg_evt(fmt, ...) \
 226         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 227 #define ec_dbg_ref(ec, fmt, ...) \
 228         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 229
 230 /* --------------------------------------------------------------------------
 231  *                           Device Flags
 232  * -------------------------------------------------------------------------- */
 233
 234 static bool acpi_ec_started(struct acpi_ec *ec)
 235 {
 236         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 237                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 238 }
 239
 240 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 241 {
 242         /*
 243          * There is an OSPM early stage logic. During the early stages
 244          * (boot/resume), OSPMs shouldn't enable the event handling, only
 245          * the EC transactions are allowed to be performed.
 246          */
 247         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 248                 return false;
 249         /*
 250          * However, disabling the event handling is experimental for late
 251          * stage (suspend), and is controlled by the boot parameter of
 252          * "ec_freeze_events":
 253          * 1. true:  The EC event handling is disabled before entering
 254          *           the noirq stage.
 255          * 2. false: The EC event handling is automatically disabled as
 256          *           soon as the EC driver is stopped.
 257          */
 258         if (ec_freeze_events)
 259                 return acpi_ec_started(ec);
 260         else
 261                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 262 }
 263
 264 static bool acpi_ec_flushed(struct acpi_ec *ec)
 265 {
 266         return ec->reference_count == 1;
 267 }
 268
 269 /* --------------------------------------------------------------------------
 270  *                           EC Registers
 271  * -------------------------------------------------------------------------- */
 272
 273 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 274 {
 275         u8 x = inb(ec->command_addr);
 276
 277         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 278                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 279                    x,
 280                    !!(x & ACPI_EC_FLAG_SCI),
 281                    !!(x & ACPI_EC_FLAG_BURST),
 282                    !!(x & ACPI_EC_FLAG_CMD),
 283                    !!(x & ACPI_EC_FLAG_IBF),
 284                    !!(x & ACPI_EC_FLAG_OBF));
 285         return x;
 286 }
 287
 288 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 289 {
 290         u8 x = inb(ec->data_addr);
 291
 292         ec->timestamp = jiffies;
 293         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 294         return x;
 295 }
 296
 297 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 298 {
 299         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 300         outb(command, ec->command_addr);
 301         ec->timestamp = jiffies;
 302 }
 303
 304 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 305 {
 306         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 307         outb(data, ec->data_addr);
 308         ec->timestamp = jiffies;
 309 }
 310
 311 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 312 static const char *acpi_ec_cmd_string(u8 cmd)
 313 {
 314         switch (cmd) {
 315         case 0x80:
 316                 return "RD_EC";
 317         case 0x81:
 318                 return "WR_EC";
 319         case 0x82:
 320                 return "BE_EC";
 321         case 0x83:
 322                 return "BD_EC";
 323         case 0x84:
 324                 return "QR_EC";
 325         }
 326         return "UNKNOWN";
 327 }
 328 #else
 329 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 330 #endif
 331
 332 /* --------------------------------------------------------------------------
 333  *                           GPE Registers
 334  * -------------------------------------------------------------------------- */
 335
 336 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 337 {
 338         acpi_event_status gpe_status = 0;
 339
 340         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 341         return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 342 }
 343
 344 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 345 {
 346         if (open)
 347                 acpi_enable_gpe(NULL, ec->gpe);
 348         else {
 349                 BUG_ON(ec->reference_count < 1);
 350                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 351         }
 352         if (acpi_ec_gpe_status_set(ec)) {
 353                 /*
 354                  * On some platforms, EN=1 writes cannot trigger GPE. So
 355                  * software need to manually trigger a pseudo GPE event on
 356                  * EN=1 writes.
 357                  */
 358                 ec_dbg_raw("Polling quirk");
 359                 advance_transaction(ec, false);
 360         }
 361 }
 362
 363 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 364 {
 365         if (close)
 366                 acpi_disable_gpe(NULL, ec->gpe);
 367         else {
 368                 BUG_ON(ec->reference_count < 1);
 369                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 370         }
 371 }
 372
 373 /* --------------------------------------------------------------------------
 374  *                           Transaction Management
 375  * -------------------------------------------------------------------------- */
 376
 377 static void acpi_ec_submit_request(struct acpi_ec *ec)
 378 {
 379         ec->reference_count++;
 380         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 381             ec->gpe >= 0 && ec->reference_count == 1)
 382                 acpi_ec_enable_gpe(ec, true);
 383 }
 384
 385 static void acpi_ec_complete_request(struct acpi_ec *ec)
 386 {
 387         bool flushed = false;
 388
 389         ec->reference_count--;
 390         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 391             ec->gpe >= 0 && ec->reference_count == 0)
 392                 acpi_ec_disable_gpe(ec, true);
 393         flushed = acpi_ec_flushed(ec);
 394         if (flushed)
 395                 wake_up(&ec->wait);
 396 }
 397
 398 static void acpi_ec_mask_events(struct acpi_ec *ec)
 399 {
 400         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 401                 if (ec->gpe >= 0)
 402                         acpi_ec_disable_gpe(ec, false);
 403                 else
 404                         disable_irq_nosync(ec->irq);
 405
 406                 ec_dbg_drv("Polling enabled");
 407                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 408         }
 409 }
 410
 411 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 412 {
 413         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 414                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 415                 if (ec->gpe >= 0)
 416                         acpi_ec_enable_gpe(ec, false);
 417                 else
 418                         enable_irq(ec->irq);
 419
 420                 ec_dbg_drv("Polling disabled");
 421         }
 422 }
 423
 424 /*
 425  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 426  *                                      the flush operation is not in
 427  *                                      progress
 428  * @ec: the EC device
 429  *
 430  * This function must be used before taking a new action that should hold
 431  * the reference count.  If this function returns false, then the action
 432  * must be discarded or it will prevent the flush operation from being
 433  * completed.
 434  */
 435 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 436 {
 437         if (!acpi_ec_started(ec))
 438                 return false;
 439         acpi_ec_submit_request(ec);
 440         return true;
 441 }
 442
 443 static void acpi_ec_submit_event(struct acpi_ec *ec)
 444 {
 445         /*
 446          * It is safe to mask the events here, because acpi_ec_close_event()
 447          * will run at least once after this.
 448          */
 449         acpi_ec_mask_events(ec);
 450         if (!acpi_ec_event_enabled(ec))
 451                 return;
 452
 453         if (ec->event_state != EC_EVENT_READY)
 454                 return;
 455
 456         ec_dbg_evt("Command(%s) submitted/blocked",
 457                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 458
 459         ec->event_state = EC_EVENT_IN_PROGRESS;
 460         /*
 461          * If events_to_process is greater than 0 at this point, the while ()
 462          * loop in acpi_ec_event_handler() is still running and incrementing
 463          * events_to_process will cause it to invoke acpi_ec_submit_query() once
 464          * more, so it is not necessary to queue up the event work to start the
 465          * same loop again.
 466          */
 467         if (ec->events_to_process++ > 0)
 468                 return;
 469
 470         ec->events_in_progress++;
 471         queue_work(ec_wq, &ec->work);
 472 }
 473
 474 static void acpi_ec_complete_event(struct acpi_ec *ec)
 475 {
 476         if (ec->event_state == EC_EVENT_IN_PROGRESS)
 477                 ec->event_state = EC_EVENT_COMPLETE;
 478 }
 479
 480 static void acpi_ec_close_event(struct acpi_ec *ec)
 481 {
 482         if (ec->event_state != EC_EVENT_READY)
 483                 ec_dbg_evt("Command(%s) unblocked",
 484                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 485
 486         ec->event_state = EC_EVENT_READY;
 487         acpi_ec_unmask_events(ec);
 488 }
 489
 490 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 491 {
 492         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 493                 ec_log_drv("event unblocked");
 494         /*
 495          * Unconditionally invoke this once after enabling the event
 496          * handling mechanism to detect the pending events.
 497          */
 498         advance_transaction(ec, false);
 499 }
 500
 501 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 502 {
 503         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 504                 ec_log_drv("event blocked");
 505 }
 506
 507 /*
 508  * Process _Q events that might have accumulated in the EC.
 509  * Run with locked ec mutex.
 510  */
 511 static void acpi_ec_clear(struct acpi_ec *ec)
 512 {
 513         int i;
 514
 515         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 516                 if (acpi_ec_submit_query(ec))
 517                         break;
 518         }
 519         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 520                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 521         else
 522                 pr_info("%d stale EC events cleared\n", i);
 523 }
 524
 525 static void acpi_ec_enable_event(struct acpi_ec *ec)
 526 {
 527         unsigned long flags;
 528
 529         spin_lock_irqsave(&ec->lock, flags);
 530         if (acpi_ec_started(ec))
 531                 __acpi_ec_enable_event(ec);
 532         spin_unlock_irqrestore(&ec->lock, flags);
 533
 534         /* Drain additional events if hardware requires that */
 535         if (EC_FLAGS_CLEAR_ON_RESUME)
 536                 acpi_ec_clear(ec);
 537 }
 538
 539 #ifdef CONFIG_PM_SLEEP
 540 static void __acpi_ec_flush_work(void)
 541 {
 542         flush_workqueue(ec_wq); /* flush ec->work */
 543         flush_workqueue(ec_query_wq); /* flush queries */
 544 }
 545
 546 static void acpi_ec_disable_event(struct acpi_ec *ec)
 547 {
 548         unsigned long flags;
 549
 550         spin_lock_irqsave(&ec->lock, flags);
 551         __acpi_ec_disable_event(ec);
 552         spin_unlock_irqrestore(&ec->lock, flags);
 553
 554         /*
 555          * When ec_freeze_events is true, we need to flush events in
 556          * the proper position before entering the noirq stage.
 557          */
 558         __acpi_ec_flush_work();
 559 }
 560
 561 void acpi_ec_flush_work(void)
 562 {
 563         /* Without ec_wq there is nothing to flush. */
 564         if (!ec_wq)
 565                 return;
 566
 567         __acpi_ec_flush_work();
 568 }
 569 #endif /* CONFIG_PM_SLEEP */
 570
 571 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 572 {
 573         unsigned long flags;
 574         bool guarded;
 575
 576         spin_lock_irqsave(&ec->lock, flags);
 577         /*
 578          * If firmware SCI_EVT clearing timing is "event", we actually
 579          * don't know when the SCI_EVT will be cleared by firmware after
 580          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 581          * acceptable period.
 582          *
 583          * The guarding period is applicable if the event state is not
 584          * EC_EVENT_READY, but otherwise if the current transaction is of the
 585          * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
 586          * and it should not be applied to let the transaction transition into
 587          * the ACPI_EC_COMMAND_POLL state immediately.
 588          */
 589         guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 590                 ec->event_state != EC_EVENT_READY &&
 591                 (!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
 592         spin_unlock_irqrestore(&ec->lock, flags);
 593         return guarded;
 594 }
 595
 596 static int ec_transaction_polled(struct acpi_ec *ec)
 597 {
 598         unsigned long flags;
 599         int ret = 0;
 600
 601         spin_lock_irqsave(&ec->lock, flags);
 602         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 603                 ret = 1;
 604         spin_unlock_irqrestore(&ec->lock, flags);
 605         return ret;
 606 }
 607
 608 static int ec_transaction_completed(struct acpi_ec *ec)
 609 {
 610         unsigned long flags;
 611         int ret = 0;
 612
 613         spin_lock_irqsave(&ec->lock, flags);
 614         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 615                 ret = 1;
 616         spin_unlock_irqrestore(&ec->lock, flags);
 617         return ret;
 618 }
 619
 620 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 621 {
 622         ec->curr->flags |= flag;
 623
 624         if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
 625                 return;
 626
 627         switch (ec_event_clearing) {
 628         case ACPI_EC_EVT_TIMING_STATUS:
 629                 if (flag == ACPI_EC_COMMAND_POLL)
 630                         acpi_ec_close_event(ec);
 631
 632                 return;
 633
 634         case ACPI_EC_EVT_TIMING_QUERY:
 635                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 636                         acpi_ec_close_event(ec);
 637
 638                 return;
 639
 640         case ACPI_EC_EVT_TIMING_EVENT:
 641                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 642                         acpi_ec_complete_event(ec);
 643         }
 644 }
 645
 646 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 647 {
 648         if (t->irq_count < ec_storm_threshold)
 649                 ++t->irq_count;
 650
 651         /* Trigger if the threshold is 0 too. */
 652         if (t->irq_count == ec_storm_threshold)
 653                 acpi_ec_mask_events(ec);
 654 }
 655
 656 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 657 {
 658         struct transaction *t = ec->curr;
 659         bool wakeup = false;
 660         u8 status;
 661
 662         ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 663
 664         /*
 665          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
 666          * changes to always trigger a GPE interrupt.
 667          *
 668          * GPE STS is a W1C register, which means:
 669          *
 670          * 1. Software can clear it without worrying about clearing the other
 671          *    GPEs' STS bits when the hardware sets them in parallel.
 672          *
 673          * 2. As long as software can ensure only clearing it when it is set,
 674          *    hardware won't set it in parallel.
 675          */
 676         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
 677                 acpi_clear_gpe(NULL, ec->gpe);
 678
 679         status = acpi_ec_read_status(ec);
 680
 681         /*
 682          * Another IRQ or a guarded polling mode advancement is detected,
 683          * the next QR_EC submission is then allowed.
 684          */
 685         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 686                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 687                     ec->event_state == EC_EVENT_COMPLETE)
 688                         acpi_ec_close_event(ec);
 689
 690                 if (!t)
 691                         goto out;
 692         }
 693
 694         if (t->flags & ACPI_EC_COMMAND_POLL) {
 695                 if (t->wlen > t->wi) {
 696                         if (!(status & ACPI_EC_FLAG_IBF))
 697                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 698                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 699                                 acpi_ec_spurious_interrupt(ec, t);
 700                 } else if (t->rlen > t->ri) {
 701                         if (status & ACPI_EC_FLAG_OBF) {
 702                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 703                                 if (t->rlen == t->ri) {
 704                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 705                                         wakeup = true;
 706                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 707                                                 ec_dbg_evt("Command(%s) completed by hardware",
 708                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 709                                 }
 710                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 711                                 acpi_ec_spurious_interrupt(ec, t);
 712                         }
 713                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 714                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 715                         wakeup = true;
 716                 }
 717         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 718                 acpi_ec_write_cmd(ec, t->command);
 719                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 720         }
 721
 722 out:
 723         if (status & ACPI_EC_FLAG_SCI)
 724                 acpi_ec_submit_event(ec);
 725
 726         if (wakeup && interrupt)
 727                 wake_up(&ec->wait);
 728 }
 729
 730 static void start_transaction(struct acpi_ec *ec)
 731 {
 732         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 733         ec->curr->flags = 0;
 734 }
 735
 736 static int ec_guard(struct acpi_ec *ec)
 737 {
 738         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 739         unsigned long timeout = ec->timestamp + guard;
 740
 741         /* Ensure guarding period before polling EC status */
 742         do {
 743                 if (ec->busy_polling) {
 744                         /* Perform busy polling */
 745                         if (ec_transaction_completed(ec))
 746                                 return 0;
 747                         udelay(jiffies_to_usecs(guard));
 748                 } else {
 749                         /*
 750                          * Perform wait polling
 751                          * 1. Wait the transaction to be completed by the
 752                          *    GPE handler after the transaction enters
 753                          *    ACPI_EC_COMMAND_POLL state.
 754                          * 2. A special guarding logic is also required
 755                          *    for event clearing mode "event" before the
 756                          *    transaction enters ACPI_EC_COMMAND_POLL
 757                          *    state.
 758                          */
 759                         if (!ec_transaction_polled(ec) &&
 760                             !acpi_ec_guard_event(ec))
 761                                 break;
 762                         if (wait_event_timeout(ec->wait,
 763                                                ec_transaction_completed(ec),
 764                                                guard))
 765                                 return 0;
 766                 }
 767         } while (time_before(jiffies, timeout));
 768         return -ETIME;
 769 }
 770
 771 static int ec_poll(struct acpi_ec *ec)
 772 {
 773         unsigned long flags;
 774         int repeat = 5; /* number of command restarts */
 775
 776         while (repeat--) {
 777                 unsigned long delay = jiffies +
 778                         msecs_to_jiffies(ec_delay);
 779                 do {
 780                         if (!ec_guard(ec))
 781                                 return 0;
 782                         spin_lock_irqsave(&ec->lock, flags);
 783                         advance_transaction(ec, false);
 784                         spin_unlock_irqrestore(&ec->lock, flags);
 785                 } while (time_before(jiffies, delay));
 786                 pr_debug("controller reset, restart transaction\n");
 787                 spin_lock_irqsave(&ec->lock, flags);
 788                 start_transaction(ec);
 789                 spin_unlock_irqrestore(&ec->lock, flags);
 790         }
 791         return -ETIME;
 792 }
 793
 794 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 795                                         struct transaction *t)
 796 {
 797         unsigned long tmp;
 798         int ret = 0;
 799
 800         /* start transaction */
 801         spin_lock_irqsave(&ec->lock, tmp);
 802         /* Enable GPE for command processing (IBF=0/OBF=1) */
 803         if (!acpi_ec_submit_flushable_request(ec)) {
 804                 ret = -EINVAL;
 805                 goto unlock;
 806         }
 807         ec_dbg_ref(ec, "Increase command");
 808         /* following two actions should be kept atomic */
 809         ec->curr = t;
 810         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 811         start_transaction(ec);
 812         spin_unlock_irqrestore(&ec->lock, tmp);
 813
 814         ret = ec_poll(ec);
 815
 816         spin_lock_irqsave(&ec->lock, tmp);
 817         if (t->irq_count == ec_storm_threshold)
 818                 acpi_ec_unmask_events(ec);
 819         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 820         ec->curr = NULL;
 821         /* Disable GPE for command processing (IBF=0/OBF=1) */
 822         acpi_ec_complete_request(ec);
 823         ec_dbg_ref(ec, "Decrease command");
 824 unlock:
 825         spin_unlock_irqrestore(&ec->lock, tmp);
 826         return ret;
 827 }
 828
 829 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 830 {
 831         int status;
 832         u32 glk;
 833
 834         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 835                 return -EINVAL;
 836         if (t->rdata)
 837                 memset(t->rdata, 0, t->rlen);
 838
 839         mutex_lock(&ec->mutex);
 840         if (ec->global_lock) {
 841                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 842                 if (ACPI_FAILURE(status)) {
 843                         status = -ENODEV;
 844                         goto unlock;
 845                 }
 846         }
 847
 848         status = acpi_ec_transaction_unlocked(ec, t);
 849
 850         if (ec->global_lock)
 851                 acpi_release_global_lock(glk);
 852 unlock:
 853         mutex_unlock(&ec->mutex);
 854         return status;
 855 }
 856
 857 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 858 {
 859         u8 d;
 860         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 861                                 .wdata = NULL, .rdata = &d,
 862                                 .wlen = 0, .rlen = 1};
 863
 864         return acpi_ec_transaction(ec, &t);
 865 }
 866
 867 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 868 {
 869         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 870                                 .wdata = NULL, .rdata = NULL,
 871                                 .wlen = 0, .rlen = 0};
 872
 873         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 874                                 acpi_ec_transaction(ec, &t) : 0;
 875 }
 876
 877 static int acpi_ec_read(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(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 int ec_read(u8 addr, u8 *val)
 901 {
 902         int err;
 903         u8 temp_data;
 904
 905         if (!first_ec)
 906                 return -ENODEV;
 907
 908         err = acpi_ec_read(first_ec, addr, &temp_data);
 909
 910         if (!err) {
 911                 *val = temp_data;
 912                 return 0;
 913         }
 914         return err;
 915 }
 916 EXPORT_SYMBOL(ec_read);
 917
 918 int ec_write(u8 addr, u8 val)
 919 {
 920         int err;
 921
 922         if (!first_ec)
 923                 return -ENODEV;
 924
 925         err = acpi_ec_write(first_ec, addr, val);
 926
 927         return err;
 928 }
 929 EXPORT_SYMBOL(ec_write);
 930
 931 int ec_transaction(u8 command,
 932                    const u8 *wdata, unsigned wdata_len,
 933                    u8 *rdata, unsigned rdata_len)
 934 {
 935         struct transaction t = {.command = command,
 936                                 .wdata = wdata, .rdata = rdata,
 937                                 .wlen = wdata_len, .rlen = rdata_len};
 938
 939         if (!first_ec)
 940                 return -ENODEV;
 941
 942         return acpi_ec_transaction(first_ec, &t);
 943 }
 944 EXPORT_SYMBOL(ec_transaction);
 945
 946 /* Get the handle to the EC device */
 947 acpi_handle ec_get_handle(void)
 948 {
 949         if (!first_ec)
 950                 return NULL;
 951         return first_ec->handle;
 952 }
 953 EXPORT_SYMBOL(ec_get_handle);
 954
 955 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 956 {
 957         unsigned long flags;
 958
 959         spin_lock_irqsave(&ec->lock, flags);
 960         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 961                 ec_dbg_drv("Starting EC");
 962                 /* Enable GPE for event processing (SCI_EVT=1) */
 963                 if (!resuming) {
 964                         acpi_ec_submit_request(ec);
 965                         ec_dbg_ref(ec, "Increase driver");
 966                 }
 967                 ec_log_drv("EC started");
 968         }
 969         spin_unlock_irqrestore(&ec->lock, flags);
 970 }
 971
 972 static bool acpi_ec_stopped(struct acpi_ec *ec)
 973 {
 974         unsigned long flags;
 975         bool flushed;
 976
 977         spin_lock_irqsave(&ec->lock, flags);
 978         flushed = acpi_ec_flushed(ec);
 979         spin_unlock_irqrestore(&ec->lock, flags);
 980         return flushed;
 981 }
 982
 983 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 984 {
 985         unsigned long flags;
 986
 987         spin_lock_irqsave(&ec->lock, flags);
 988         if (acpi_ec_started(ec)) {
 989                 ec_dbg_drv("Stopping EC");
 990                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 991                 spin_unlock_irqrestore(&ec->lock, flags);
 992                 wait_event(ec->wait, acpi_ec_stopped(ec));
 993                 spin_lock_irqsave(&ec->lock, flags);
 994                 /* Disable GPE for event processing (SCI_EVT=1) */
 995                 if (!suspending) {
 996                         acpi_ec_complete_request(ec);
 997                         ec_dbg_ref(ec, "Decrease driver");
 998                 } else if (!ec_freeze_events)
 999                         __acpi_ec_disable_event(ec);
1000                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
1001                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1002                 ec_log_drv("EC stopped");
1003         }
1004         spin_unlock_irqrestore(&ec->lock, flags);
1005 }
1006
1007 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1008 {
1009         unsigned long flags;
1010
1011         spin_lock_irqsave(&ec->lock, flags);
1012         ec->busy_polling = true;
1013         ec->polling_guard = 0;
1014         ec_log_drv("interrupt blocked");
1015         spin_unlock_irqrestore(&ec->lock, flags);
1016 }
1017
1018 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1019 {
1020         unsigned long flags;
1021
1022         spin_lock_irqsave(&ec->lock, flags);
1023         ec->busy_polling = ec_busy_polling;
1024         ec->polling_guard = ec_polling_guard;
1025         ec_log_drv("interrupt unblocked");
1026         spin_unlock_irqrestore(&ec->lock, flags);
1027 }
1028
1029 void acpi_ec_block_transactions(void)
1030 {
1031         struct acpi_ec *ec = first_ec;
1032
1033         if (!ec)
1034                 return;
1035
1036         mutex_lock(&ec->mutex);
1037         /* Prevent transactions from being carried out */
1038         acpi_ec_stop(ec, true);
1039         mutex_unlock(&ec->mutex);
1040 }
1041
1042 void acpi_ec_unblock_transactions(void)
1043 {
1044         /*
1045          * Allow transactions to happen again (this function is called from
1046          * atomic context during wakeup, so we don't need to acquire the mutex).
1047          */
1048         if (first_ec)
1049                 acpi_ec_start(first_ec, true);
1050 }
1051
1052 /* --------------------------------------------------------------------------
1053                                 Event Management
1054    -------------------------------------------------------------------------- */
1055 static struct acpi_ec_query_handler *
1056 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1057 {
1058         struct acpi_ec_query_handler *handler;
1059
1060         mutex_lock(&ec->mutex);
1061         list_for_each_entry(handler, &ec->list, node) {
1062                 if (value == handler->query_bit) {
1063                         kref_get(&handler->kref);
1064                         mutex_unlock(&ec->mutex);
1065                         return handler;
1066                 }
1067         }
1068         mutex_unlock(&ec->mutex);
1069         return NULL;
1070 }
1071
1072 static void acpi_ec_query_handler_release(struct kref *kref)
1073 {
1074         struct acpi_ec_query_handler *handler =
1075                 container_of(kref, struct acpi_ec_query_handler, kref);
1076
1077         kfree(handler);
1078 }
1079
1080 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1081 {
1082         kref_put(&handler->kref, acpi_ec_query_handler_release);
1083 }
1084
1085 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1086                               acpi_handle handle, acpi_ec_query_func func,
1087                               void *data)
1088 {
1089         struct acpi_ec_query_handler *handler =
1090             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1091
1092         if (!handler)
1093                 return -ENOMEM;
1094
1095         handler->query_bit = query_bit;
1096         handler->handle = handle;
1097         handler->func = func;
1098         handler->data = data;
1099         mutex_lock(&ec->mutex);
1100         kref_init(&handler->kref);
1101         list_add(&handler->node, &ec->list);
1102         mutex_unlock(&ec->mutex);
1103         return 0;
1104 }
1105 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1106
1107 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1108                                           bool remove_all, u8 query_bit)
1109 {
1110         struct acpi_ec_query_handler *handler, *tmp;
1111         LIST_HEAD(free_list);
1112
1113         mutex_lock(&ec->mutex);
1114         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1115                 if (remove_all || query_bit == handler->query_bit) {
1116                         list_del_init(&handler->node);
1117                         list_add(&handler->node, &free_list);
1118                 }
1119         }
1120         mutex_unlock(&ec->mutex);
1121         list_for_each_entry_safe(handler, tmp, &free_list, node)
1122                 acpi_ec_put_query_handler(handler);
1123 }
1124
1125 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1126 {
1127         acpi_ec_remove_query_handlers(ec, false, query_bit);
1128 }
1129 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1130
1131 static void acpi_ec_event_processor(struct work_struct *work)
1132 {
1133         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1134         struct acpi_ec_query_handler *handler = q->handler;
1135         struct acpi_ec *ec = q->ec;
1136
1137         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1138
1139         if (handler->func)
1140                 handler->func(handler->data);
1141         else if (handler->handle)
1142                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1143
1144         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1145
1146         spin_lock_irq(&ec->lock);
1147         ec->queries_in_progress--;
1148         spin_unlock_irq(&ec->lock);
1149
1150         acpi_ec_put_query_handler(handler);
1151         kfree(q);
1152 }
1153
1154 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1155 {
1156         struct acpi_ec_query *q;
1157         struct transaction *t;
1158
1159         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1160         if (!q)
1161                 return NULL;
1162
1163         INIT_WORK(&q->work, acpi_ec_event_processor);
1164         t = &q->transaction;
1165         t->command = ACPI_EC_COMMAND_QUERY;
1166         t->rdata = pval;
1167         t->rlen = 1;
1168         q->ec = ec;
1169         return q;
1170 }
1171
1172 static int acpi_ec_submit_query(struct acpi_ec *ec)
1173 {
1174         struct acpi_ec_query *q;
1175         u8 value = 0;
1176         int result;
1177
1178         q = acpi_ec_create_query(ec, &value);
1179         if (!q)
1180                 return -ENOMEM;
1181
1182         /*
1183          * Query the EC to find out which _Qxx method we need to evaluate.
1184          * Note that successful completion of the query causes the ACPI_EC_SCI
1185          * bit to be cleared (and thus clearing the interrupt source).
1186          */
1187         result = acpi_ec_transaction(ec, &q->transaction);
1188         if (result)
1189                 goto err_exit;
1190
1191         if (!value) {
1192                 result = -ENODATA;
1193                 goto err_exit;
1194         }
1195
1196         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1197         if (!q->handler) {
1198                 result = -ENODATA;
1199                 goto err_exit;
1200         }
1201
1202         /*
1203          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1204          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1205          *
1206          * Put this log entry before queue_work() to make it appear in the log
1207          * before any other messages emitted during workqueue handling.
1208          */
1209         ec_dbg_evt("Query(0x%02x) scheduled", value);
1210
1211         spin_lock_irq(&ec->lock);
1212
1213         ec->queries_in_progress++;
1214         queue_work(ec_query_wq, &q->work);
1215
1216         spin_unlock_irq(&ec->lock);
1217
1218         return 0;
1219
1220 err_exit:
1221         kfree(q);
1222
1223         return result;
1224 }
1225
1226 static void acpi_ec_event_handler(struct work_struct *work)
1227 {
1228         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1229
1230         ec_dbg_evt("Event started");
1231
1232         spin_lock_irq(&ec->lock);
1233
1234         while (ec->events_to_process) {
1235                 spin_unlock_irq(&ec->lock);
1236
1237                 acpi_ec_submit_query(ec);
1238
1239                 spin_lock_irq(&ec->lock);
1240
1241                 ec->events_to_process--;
1242         }
1243
1244         /*
1245          * Before exit, make sure that the it will be possible to queue up the
1246          * event handling work again regardless of whether or not the query
1247          * queued up above is processed successfully.
1248          */
1249         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1250                 bool guard_timeout;
1251
1252                 acpi_ec_complete_event(ec);
1253
1254                 ec_dbg_evt("Event stopped");
1255
1256                 spin_unlock_irq(&ec->lock);
1257
1258                 guard_timeout = !!ec_guard(ec);
1259
1260                 spin_lock_irq(&ec->lock);
1261
1262                 /* Take care of SCI_EVT unless someone else is doing that. */
1263                 if (guard_timeout && !ec->curr)
1264                         advance_transaction(ec, false);
1265         } else {
1266                 acpi_ec_close_event(ec);
1267
1268                 ec_dbg_evt("Event stopped");
1269         }
1270
1271         ec->events_in_progress--;
1272
1273         spin_unlock_irq(&ec->lock);
1274 }
1275
1276 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1277 {
1278         unsigned long flags;
1279
1280         spin_lock_irqsave(&ec->lock, flags);
1281         advance_transaction(ec, true);
1282         spin_unlock_irqrestore(&ec->lock, flags);
1283 }
1284
1285 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1286                                u32 gpe_number, void *data)
1287 {
1288         acpi_ec_handle_interrupt(data);
1289         return ACPI_INTERRUPT_HANDLED;
1290 }
1291
1292 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1293 {
1294         acpi_ec_handle_interrupt(data);
1295         return IRQ_HANDLED;
1296 }
1297
1298 /* --------------------------------------------------------------------------
1299  *                           Address Space Management
1300  * -------------------------------------------------------------------------- */
1301
1302 static acpi_status
1303 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1304                       u32 bits, u64 *value64,
1305                       void *handler_context, void *region_context)
1306 {
1307         struct acpi_ec *ec = handler_context;
1308         int result = 0, i, bytes = bits / 8;
1309         u8 *value = (u8 *)value64;
1310
1311         if ((address > 0xFF) || !value || !handler_context)
1312                 return AE_BAD_PARAMETER;
1313
1314         if (function != ACPI_READ && function != ACPI_WRITE)
1315                 return AE_BAD_PARAMETER;
1316
1317         if (ec->busy_polling || bits > 8)
1318                 acpi_ec_burst_enable(ec);
1319
1320         for (i = 0; i < bytes; ++i, ++address, ++value)
1321                 result = (function == ACPI_READ) ?
1322                         acpi_ec_read(ec, address, value) :
1323                         acpi_ec_write(ec, address, *value);
1324
1325         if (ec->busy_polling || bits > 8)
1326                 acpi_ec_burst_disable(ec);
1327
1328         switch (result) {
1329         case -EINVAL:
1330                 return AE_BAD_PARAMETER;
1331         case -ENODEV:
1332                 return AE_NOT_FOUND;
1333         case -ETIME:
1334                 return AE_TIME;
1335         default:
1336                 return AE_OK;
1337         }
1338 }
1339
1340 /* --------------------------------------------------------------------------
1341  *                             Driver Interface
1342  * -------------------------------------------------------------------------- */
1343
1344 static acpi_status
1345 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1346
1347 static void acpi_ec_free(struct acpi_ec *ec)
1348 {
1349         if (first_ec == ec)
1350                 first_ec = NULL;
1351         if (boot_ec == ec)
1352                 boot_ec = NULL;
1353         kfree(ec);
1354 }
1355
1356 static struct acpi_ec *acpi_ec_alloc(void)
1357 {
1358         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1359
1360         if (!ec)
1361                 return NULL;
1362         mutex_init(&ec->mutex);
1363         init_waitqueue_head(&ec->wait);
1364         INIT_LIST_HEAD(&ec->list);
1365         spin_lock_init(&ec->lock);
1366         INIT_WORK(&ec->work, acpi_ec_event_handler);
1367         ec->timestamp = jiffies;
1368         ec->busy_polling = true;
1369         ec->polling_guard = 0;
1370         ec->gpe = -1;
1371         ec->irq = -1;
1372         return ec;
1373 }
1374
1375 static acpi_status
1376 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1377                                void *context, void **return_value)
1378 {
1379         char node_name[5];
1380         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1381         struct acpi_ec *ec = context;
1382         int value = 0;
1383         acpi_status status;
1384
1385         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1386
1387         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1388                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1389         return AE_OK;
1390 }
1391
1392 static acpi_status
1393 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1394 {
1395         acpi_status status;
1396         unsigned long long tmp = 0;
1397         struct acpi_ec *ec = context;
1398
1399         /* clear addr values, ec_parse_io_ports depend on it */
1400         ec->command_addr = ec->data_addr = 0;
1401
1402         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1403                                      ec_parse_io_ports, ec);
1404         if (ACPI_FAILURE(status))
1405                 return status;
1406         if (ec->data_addr == 0 || ec->command_addr == 0)
1407                 return AE_OK;
1408
1409         /* Get GPE bit assignment (EC events). */
1410         /* TODO: Add support for _GPE returning a package */
1411         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1412         if (ACPI_SUCCESS(status))
1413                 ec->gpe = tmp;
1414         /*
1415          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1416          * platforms which use GpioInt instead of GPE.
1417          */
1418
1419         /* Use the global lock for all EC transactions? */
1420         tmp = 0;
1421         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1422         ec->global_lock = tmp;
1423         ec->handle = handle;
1424         return AE_CTRL_TERMINATE;
1425 }
1426
1427 static bool install_gpe_event_handler(struct acpi_ec *ec)
1428 {
1429         acpi_status status;
1430
1431         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1432                                               ACPI_GPE_EDGE_TRIGGERED,
1433                                               &acpi_ec_gpe_handler, ec);
1434         if (ACPI_FAILURE(status))
1435                 return false;
1436
1437         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1438                 acpi_ec_enable_gpe(ec, true);
1439
1440         return true;
1441 }
1442
1443 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1444 {
1445         return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1446                            "ACPI EC", ec) >= 0;
1447 }
1448
1449 /**
1450  * ec_install_handlers - Install service callbacks and register query methods.
1451  * @ec: Target EC.
1452  * @device: ACPI device object corresponding to @ec.
1453  *
1454  * Install a handler for the EC address space type unless it has been installed
1455  * already.  If @device is not NULL, also look for EC query methods in the
1456  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1457  * handler for the EC, if possible.
1458  *
1459  * Return:
1460  * -ENODEV if the address space handler cannot be installed, which means
1461  *  "unable to handle transactions",
1462  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1463  * or 0 (success) otherwise.
1464  */
1465 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1466 {
1467         acpi_status status;
1468
1469         acpi_ec_start(ec, false);
1470
1471         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1472                 acpi_ec_enter_noirq(ec);
1473                 status = acpi_install_address_space_handler(ec->handle,
1474                                                             ACPI_ADR_SPACE_EC,
1475                                                             &acpi_ec_space_handler,
1476                                                             NULL, ec);
1477                 if (ACPI_FAILURE(status)) {
1478                         acpi_ec_stop(ec, false);
1479                         return -ENODEV;
1480                 }
1481                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1482         }
1483
1484         if (!device)
1485                 return 0;
1486
1487         if (ec->gpe < 0) {
1488                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1489                 int irq = acpi_dev_gpio_irq_get(device, 0);
1490                 /*
1491                  * Bail out right away for deferred probing or complete the
1492                  * initialization regardless of any other errors.
1493                  */
1494                 if (irq == -EPROBE_DEFER)
1495                         return -EPROBE_DEFER;
1496                 else if (irq >= 0)
1497                         ec->irq = irq;
1498         }
1499
1500         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1501                 /* Find and register all query methods */
1502                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1503                                     acpi_ec_register_query_methods,
1504                                     NULL, ec, NULL);
1505                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1506         }
1507         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1508                 bool ready = false;
1509
1510                 if (ec->gpe >= 0)
1511                         ready = install_gpe_event_handler(ec);
1512                 else if (ec->irq >= 0)
1513                         ready = install_gpio_irq_event_handler(ec);
1514
1515                 if (ready) {
1516                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1517                         acpi_ec_leave_noirq(ec);
1518                 }
1519                 /*
1520                  * Failures to install an event handler are not fatal, because
1521                  * the EC can be polled for events.
1522                  */
1523         }
1524         /* EC is fully operational, allow queries */
1525         acpi_ec_enable_event(ec);
1526
1527         return 0;
1528 }
1529
1530 static void ec_remove_handlers(struct acpi_ec *ec)
1531 {
1532         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1533                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1534                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1535                         pr_err("failed to remove space handler\n");
1536                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1537         }
1538
1539         /*
1540          * Stops handling the EC transactions after removing the operation
1541          * region handler. This is required because _REG(DISCONNECT)
1542          * invoked during the removal can result in new EC transactions.
1543          *
1544          * Flushes the EC requests and thus disables the GPE before
1545          * removing the GPE handler. This is required by the current ACPICA
1546          * GPE core. ACPICA GPE core will automatically disable a GPE when
1547          * it is indicated but there is no way to handle it. So the drivers
1548          * must disable the GPEs prior to removing the GPE handlers.
1549          */
1550         acpi_ec_stop(ec, false);
1551
1552         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1553                 if (ec->gpe >= 0 &&
1554                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1555                                  &acpi_ec_gpe_handler)))
1556                         pr_err("failed to remove gpe handler\n");
1557
1558                 if (ec->irq >= 0)
1559                         free_irq(ec->irq, ec);
1560
1561                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1562         }
1563         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1564                 acpi_ec_remove_query_handlers(ec, true, 0);
1565                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1566         }
1567 }
1568
1569 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1570 {
1571         int ret;
1572
1573         ret = ec_install_handlers(ec, device);
1574         if (ret)
1575                 return ret;
1576
1577         /* First EC capable of handling transactions */
1578         if (!first_ec)
1579                 first_ec = ec;
1580
1581         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1582                 ec->data_addr);
1583
1584         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1585                 if (ec->gpe >= 0)
1586                         pr_info("GPE=0x%x\n", ec->gpe);
1587                 else
1588                         pr_info("IRQ=%d\n", ec->irq);
1589         }
1590
1591         return ret;
1592 }
1593
1594 static int acpi_ec_add(struct acpi_device *device)
1595 {
1596         struct acpi_ec *ec;
1597         int ret;
1598
1599         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1600         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1601
1602         if (boot_ec && (boot_ec->handle == device->handle ||
1603             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1604                 /* Fast path: this device corresponds to the boot EC. */
1605                 ec = boot_ec;
1606         } else {
1607                 acpi_status status;
1608
1609                 ec = acpi_ec_alloc();
1610                 if (!ec)
1611                         return -ENOMEM;
1612
1613                 status = ec_parse_device(device->handle, 0, ec, NULL);
1614                 if (status != AE_CTRL_TERMINATE) {
1615                         ret = -EINVAL;
1616                         goto err;
1617                 }
1618
1619                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1620                     ec->data_addr == boot_ec->data_addr) {
1621                         /*
1622                          * Trust PNP0C09 namespace location rather than ECDT ID.
1623                          * But trust ECDT GPE rather than _GPE because of ASUS
1624                          * quirks. So do not change boot_ec->gpe to ec->gpe,
1625                          * except when the TRUST_DSDT_GPE quirk is set.
1626                          */
1627                         boot_ec->handle = ec->handle;
1628
1629                         if (EC_FLAGS_TRUST_DSDT_GPE)
1630                                 boot_ec->gpe = ec->gpe;
1631
1632                         acpi_handle_debug(ec->handle, "duplicated.\n");
1633                         acpi_ec_free(ec);
1634                         ec = boot_ec;
1635                 }
1636         }
1637
1638         ret = acpi_ec_setup(ec, device);
1639         if (ret)
1640                 goto err;
1641
1642         if (ec == boot_ec)
1643                 acpi_handle_info(boot_ec->handle,
1644                                  "Boot %s EC initialization complete\n",
1645                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1646
1647         acpi_handle_info(ec->handle,
1648                          "EC: Used to handle transactions and events\n");
1649
1650         device->driver_data = ec;
1651
1652         ret = !!request_region(ec->data_addr, 1, "EC data");
1653         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1654         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1655         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1656
1657         /* Reprobe devices depending on the EC */
1658         acpi_dev_clear_dependencies(device);
1659
1660         acpi_handle_debug(ec->handle, "enumerated.\n");
1661         return 0;
1662
1663 err:
1664         if (ec != boot_ec)
1665                 acpi_ec_free(ec);
1666
1667         return ret;
1668 }
1669
1670 static int acpi_ec_remove(struct acpi_device *device)
1671 {
1672         struct acpi_ec *ec;
1673
1674         if (!device)
1675                 return -EINVAL;
1676
1677         ec = acpi_driver_data(device);
1678         release_region(ec->data_addr, 1);
1679         release_region(ec->command_addr, 1);
1680         device->driver_data = NULL;
1681         if (ec != boot_ec) {
1682                 ec_remove_handlers(ec);
1683                 acpi_ec_free(ec);
1684         }
1685         return 0;
1686 }
1687
1688 static acpi_status
1689 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1690 {
1691         struct acpi_ec *ec = context;
1692
1693         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1694                 return AE_OK;
1695
1696         /*
1697          * The first address region returned is the data port, and
1698          * the second address region returned is the status/command
1699          * port.
1700          */
1701         if (ec->data_addr == 0)
1702                 ec->data_addr = resource->data.io.minimum;
1703         else if (ec->command_addr == 0)
1704                 ec->command_addr = resource->data.io.minimum;
1705         else
1706                 return AE_CTRL_TERMINATE;
1707
1708         return AE_OK;
1709 }
1710
1711 static const struct acpi_device_id ec_device_ids[] = {
1712         {"PNP0C09", 0},
1713         {ACPI_ECDT_HID, 0},
1714         {"", 0},
1715 };
1716
1717 /*
1718  * This function is not Windows-compatible as Windows never enumerates the
1719  * namespace EC before the main ACPI device enumeration process. It is
1720  * retained for historical reason and will be deprecated in the future.
1721  */
1722 void __init acpi_ec_dsdt_probe(void)
1723 {
1724         struct acpi_ec *ec;
1725         acpi_status status;
1726         int ret;
1727
1728         /*
1729          * If a platform has ECDT, there is no need to proceed as the
1730          * following probe is not a part of the ACPI device enumeration,
1731          * executing _STA is not safe, and thus this probe may risk of
1732          * picking up an invalid EC device.
1733          */
1734         if (boot_ec)
1735                 return;
1736
1737         ec = acpi_ec_alloc();
1738         if (!ec)
1739                 return;
1740
1741         /*
1742          * At this point, the namespace is initialized, so start to find
1743          * the namespace objects.
1744          */
1745         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1746         if (ACPI_FAILURE(status) || !ec->handle) {
1747                 acpi_ec_free(ec);
1748                 return;
1749         }
1750
1751         /*
1752          * When the DSDT EC is available, always re-configure boot EC to
1753          * have _REG evaluated. _REG can only be evaluated after the
1754          * namespace initialization.
1755          * At this point, the GPE is not fully initialized, so do not to
1756          * handle the events.
1757          */
1758         ret = acpi_ec_setup(ec, NULL);
1759         if (ret) {
1760                 acpi_ec_free(ec);
1761                 return;
1762         }
1763
1764         boot_ec = ec;
1765
1766         acpi_handle_info(ec->handle,
1767                          "Boot DSDT EC used to handle transactions\n");
1768 }
1769
1770 /*
1771  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1772  *
1773  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1774  * found a matching object in the namespace.
1775  *
1776  * Next, in case the DSDT EC is not functioning, it is still necessary to
1777  * provide a functional ECDT EC to handle events, so add an extra device object
1778  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1779  *
1780  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1781  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1782  */
1783 static void __init acpi_ec_ecdt_start(void)
1784 {
1785         struct acpi_table_ecdt *ecdt_ptr;
1786         acpi_handle handle;
1787         acpi_status status;
1788
1789         /* Bail out if a matching EC has been found in the namespace. */
1790         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1791                 return;
1792
1793         /* Look up the object pointed to from the ECDT in the namespace. */
1794         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1795                                 (struct acpi_table_header **)&ecdt_ptr);
1796         if (ACPI_FAILURE(status))
1797                 return;
1798
1799         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1800         if (ACPI_SUCCESS(status)) {
1801                 boot_ec->handle = handle;
1802
1803                 /* Add a special ACPI device object to represent the boot EC. */
1804                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1805         }
1806
1807         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1808 }
1809
1810 /*
1811  * On some hardware it is necessary to clear events accumulated by the EC during
1812  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1813  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1814  *
1815  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1816  *
1817  * Ideally, the EC should also be instructed NOT to accumulate events during
1818  * sleep (which Windows seems to do somehow), but the interface to control this
1819  * behaviour is not known at this time.
1820  *
1821  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1822  * however it is very likely that other Samsung models are affected.
1823  *
1824  * On systems which don't accumulate _Q events during sleep, this extra check
1825  * should be harmless.
1826  */
1827 static int ec_clear_on_resume(const struct dmi_system_id *id)
1828 {
1829         pr_debug("Detected system needing EC poll on resume.\n");
1830         EC_FLAGS_CLEAR_ON_RESUME = 1;
1831         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1832         return 0;
1833 }
1834
1835 /*
1836  * Some ECDTs contain wrong register addresses.
1837  * MSI MS-171F
1838  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1839  */
1840 static int ec_correct_ecdt(const struct dmi_system_id *id)
1841 {
1842         pr_debug("Detected system needing ECDT address correction.\n");
1843         EC_FLAGS_CORRECT_ECDT = 1;
1844         return 0;
1845 }
1846
1847 /*
1848  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1849  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1850  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1851  */
1852 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1853 {
1854         pr_debug("Detected system needing DSDT GPE setting.\n");
1855         EC_FLAGS_TRUST_DSDT_GPE = 1;
1856         return 0;
1857 }
1858
1859 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1860         {
1861                 /*
1862                  * MSI MS-171F
1863                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1864                  */
1865                 .callback = ec_correct_ecdt,
1866                 .matches = {
1867                         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1868                         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1869                 },
1870         },
1871         {
1872                 /*
1873                  * HP Pavilion Gaming Laptop 15-cx0xxx
1874                  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1875                  */
1876                 .callback = ec_honor_dsdt_gpe,
1877                 .matches = {
1878                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1879                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1880                 },
1881         },
1882         {
1883                 /*
1884                  * Samsung hardware
1885                  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1886                  */
1887                 .callback = ec_clear_on_resume,
1888                 .matches = {
1889                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
1890                 },
1891         },
1892         {}
1893 };
1894
1895 void __init acpi_ec_ecdt_probe(void)
1896 {
1897         struct acpi_table_ecdt *ecdt_ptr;
1898         struct acpi_ec *ec;
1899         acpi_status status;
1900         int ret;
1901
1902         /* Generate a boot ec context. */
1903         dmi_check_system(ec_dmi_table);
1904         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1905                                 (struct acpi_table_header **)&ecdt_ptr);
1906         if (ACPI_FAILURE(status))
1907                 return;
1908
1909         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1910                 /*
1911                  * Asus X50GL:
1912                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1913                  */
1914                 goto out;
1915         }
1916
1917         ec = acpi_ec_alloc();
1918         if (!ec)
1919                 goto out;
1920
1921         if (EC_FLAGS_CORRECT_ECDT) {
1922                 ec->command_addr = ecdt_ptr->data.address;
1923                 ec->data_addr = ecdt_ptr->control.address;
1924         } else {
1925                 ec->command_addr = ecdt_ptr->control.address;
1926                 ec->data_addr = ecdt_ptr->data.address;
1927         }
1928
1929         /*
1930          * Ignore the GPE value on Reduced Hardware platforms.
1931          * Some products have this set to an erroneous value.
1932          */
1933         if (!acpi_gbl_reduced_hardware)
1934                 ec->gpe = ecdt_ptr->gpe;
1935
1936         ec->handle = ACPI_ROOT_OBJECT;
1937
1938         /*
1939          * At this point, the namespace is not initialized, so do not find
1940          * the namespace objects, or handle the events.
1941          */
1942         ret = acpi_ec_setup(ec, NULL);
1943         if (ret) {
1944                 acpi_ec_free(ec);
1945                 goto out;
1946         }
1947
1948         boot_ec = ec;
1949         boot_ec_is_ecdt = true;
1950
1951         pr_info("Boot ECDT EC used to handle transactions\n");
1952
1953 out:
1954         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1955 }
1956
1957 #ifdef CONFIG_PM_SLEEP
1958 static int acpi_ec_suspend(struct device *dev)
1959 {
1960         struct acpi_ec *ec =
1961                 acpi_driver_data(to_acpi_device(dev));
1962
1963         if (!pm_suspend_no_platform() && ec_freeze_events)
1964                 acpi_ec_disable_event(ec);
1965         return 0;
1966 }
1967
1968 static int acpi_ec_suspend_noirq(struct device *dev)
1969 {
1970         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1971
1972         /*
1973          * The SCI handler doesn't run at this point, so the GPE can be
1974          * masked at the low level without side effects.
1975          */
1976         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1977             ec->gpe >= 0 && ec->reference_count >= 1)
1978                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1979
1980         acpi_ec_enter_noirq(ec);
1981
1982         return 0;
1983 }
1984
1985 static int acpi_ec_resume_noirq(struct device *dev)
1986 {
1987         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1988
1989         acpi_ec_leave_noirq(ec);
1990
1991         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1992             ec->gpe >= 0 && ec->reference_count >= 1)
1993                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1994
1995         return 0;
1996 }
1997
1998 static int acpi_ec_resume(struct device *dev)
1999 {
2000         struct acpi_ec *ec =
2001                 acpi_driver_data(to_acpi_device(dev));
2002
2003         acpi_ec_enable_event(ec);
2004         return 0;
2005 }
2006
2007 void acpi_ec_mark_gpe_for_wake(void)
2008 {
2009         if (first_ec && !ec_no_wakeup)
2010                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2011 }
2012 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2013
2014 void acpi_ec_set_gpe_wake_mask(u8 action)
2015 {
2016         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2017                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2018 }
2019
2020 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2021 {
2022         return ec->events_in_progress + ec->queries_in_progress > 0;
2023 }
2024
2025 bool acpi_ec_dispatch_gpe(void)
2026 {
2027         bool work_in_progress = false;
2028
2029         if (!first_ec)
2030                 return acpi_any_gpe_status_set(U32_MAX);
2031
2032         /*
2033          * Report wakeup if the status bit is set for any enabled GPE other
2034          * than the EC one.
2035          */
2036         if (acpi_any_gpe_status_set(first_ec->gpe))
2037                 return true;
2038
2039         /*
2040          * Cancel the SCI wakeup and process all pending events in case there
2041          * are any wakeup ones in there.
2042          *
2043          * Note that if any non-EC GPEs are active at this point, the SCI will
2044          * retrigger after the rearming in acpi_s2idle_wake(), so no events
2045          * should be missed by canceling the wakeup here.
2046          */
2047         pm_system_cancel_wakeup();
2048
2049         /*
2050          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2051          * to allow the caller to process events properly after that.
2052          */
2053         spin_lock_irq(&first_ec->lock);
2054
2055         if (acpi_ec_gpe_status_set(first_ec)) {
2056                 pm_pr_dbg("ACPI EC GPE status set\n");
2057
2058                 advance_transaction(first_ec, false);
2059                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2060         }
2061
2062         spin_unlock_irq(&first_ec->lock);
2063
2064         if (!work_in_progress)
2065                 return false;
2066
2067         pm_pr_dbg("ACPI EC GPE dispatched\n");
2068
2069         /* Drain EC work. */
2070         do {
2071                 acpi_ec_flush_work();
2072
2073                 pm_pr_dbg("ACPI EC work flushed\n");
2074
2075                 spin_lock_irq(&first_ec->lock);
2076
2077                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2078
2079                 spin_unlock_irq(&first_ec->lock);
2080         } while (work_in_progress && !pm_wakeup_pending());
2081
2082         return false;
2083 }
2084 #endif /* CONFIG_PM_SLEEP */
2085
2086 static const struct dev_pm_ops acpi_ec_pm = {
2087         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2088         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2089 };
2090
2091 static int param_set_event_clearing(const char *val,
2092                                     const struct kernel_param *kp)
2093 {
2094         int result = 0;
2095
2096         if (!strncmp(val, "status", sizeof("status") - 1)) {
2097                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2098                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2099         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2100                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2101                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2102         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2103                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2104                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2105         } else
2106                 result = -EINVAL;
2107         return result;
2108 }
2109
2110 static int param_get_event_clearing(char *buffer,
2111                                     const struct kernel_param *kp)
2112 {
2113         switch (ec_event_clearing) {
2114         case ACPI_EC_EVT_TIMING_STATUS:
2115                 return sprintf(buffer, "status\n");
2116         case ACPI_EC_EVT_TIMING_QUERY:
2117                 return sprintf(buffer, "query\n");
2118         case ACPI_EC_EVT_TIMING_EVENT:
2119                 return sprintf(buffer, "event\n");
2120         default:
2121                 return sprintf(buffer, "invalid\n");
2122         }
2123         return 0;
2124 }
2125
2126 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2127                   NULL, 0644);
2128 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2129
2130 static struct acpi_driver acpi_ec_driver = {
2131         .name = "ec",
2132         .class = ACPI_EC_CLASS,
2133         .ids = ec_device_ids,
2134         .ops = {
2135                 .add = acpi_ec_add,
2136                 .remove = acpi_ec_remove,
2137                 },
2138         .drv.pm = &acpi_ec_pm,
2139 };
2140
2141 static void acpi_ec_destroy_workqueues(void)
2142 {
2143         if (ec_wq) {
2144                 destroy_workqueue(ec_wq);
2145                 ec_wq = NULL;
2146         }
2147         if (ec_query_wq) {
2148                 destroy_workqueue(ec_query_wq);
2149                 ec_query_wq = NULL;
2150         }
2151 }
2152
2153 static int acpi_ec_init_workqueues(void)
2154 {
2155         if (!ec_wq)
2156                 ec_wq = alloc_ordered_workqueue("kec", 0);
2157
2158         if (!ec_query_wq)
2159                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2160
2161         if (!ec_wq || !ec_query_wq) {
2162                 acpi_ec_destroy_workqueues();
2163                 return -ENODEV;
2164         }
2165         return 0;
2166 }
2167
2168 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2169         {
2170                 .matches = {
2171                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2172                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2173                 },
2174         },
2175         {
2176                 .matches = {
2177                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2178                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2179                 },
2180         },
2181         {
2182                 .matches = {
2183                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2184                         DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2185                 },
2186         },
2187         { },
2188 };
2189
2190 void __init acpi_ec_init(void)
2191 {
2192         int result;
2193
2194         result = acpi_ec_init_workqueues();
2195         if (result)
2196                 return;
2197
2198         /*
2199          * Disable EC wakeup on following systems to prevent periodic
2200          * wakeup from EC GPE.
2201          */
2202         if (dmi_check_system(acpi_ec_no_wakeup)) {
2203                 ec_no_wakeup = true;
2204                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2205         }
2206
2207         /* Driver must be registered after acpi_ec_init_workqueues(). */
2208         acpi_bus_register_driver(&acpi_ec_driver);
2209
2210         acpi_ec_ecdt_start();
2211 }
2212
2213 /* EC driver currently not unloadable */
2214 #if 0
2215 static void __exit acpi_ec_exit(void)
2216 {
2217
2218         acpi_bus_unregister_driver(&acpi_ec_driver);
2219         acpi_ec_destroy_workqueues();
2220 }
2221 #endif  /* 0 */