drivers/acpi/ec.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ec.c - ACPI Embedded Controller Driver (v3)
   4  *
   5  *  Copyright (C) 2001-2015 Intel Corporation
   6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
   7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
   9  *            2004       Luming Yu <luming.yu@intel.com>
  10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
  11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  13  */
  14
  15 /* Uncomment next line to get verbose printout */
  16 /* #define DEBUG */
  17 #define pr_fmt(fmt) "ACPI: EC: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/types.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/list.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/slab.h>
  28 #include <linux/suspend.h>
  29 #include <linux/acpi.h>
  30 #include <linux/dmi.h>
  31 #include <asm/io.h>
  32
  33 #include "internal.h"
  34
  35 #define ACPI_EC_CLASS                   "embedded_controller"
  36 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  37
  38 /* EC status register */
  39 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  40 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  41 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  42 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  43 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  44
  45 /*
  46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  47  * This leads to lots of practical timing issues for the host EC driver.
  48  * The following variations are defined (from the target EC firmware's
  49  * perspective):
  50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  51  *         target can clear SCI_EVT at any time so long as the host can see
  52  *         the indication by reading the status register (EC_SC). So the
  53  *         host should re-check SCI_EVT after the first time the SCI_EVT
  54  *         indication is seen, which is the same time the query request
  55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  56  *         at any later time could indicate another event. Normally such
  57  *         kind of EC firmware has implemented an event queue and will
  58  *         return 0x00 to indicate "no outstanding event".
  59  * QUERY: After seeing the query request (QR_EC) written to the command
  60  *        register (EC_CMD) by the host and having prepared the responding
  61  *        event value in the data register (EC_DATA), the target can safely
  62  *        clear SCI_EVT because the target can confirm that the current
  63  *        event is being handled by the host. The host then should check
  64  *        SCI_EVT right after reading the event response from the data
  65  *        register (EC_DATA).
  66  * EVENT: After seeing the event response read from the data register
  67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  68  *        target requires time to notice the change in the data register
  69  *        (EC_DATA), the host may be required to wait additional guarding
  70  *        time before checking the SCI_EVT again. Such guarding may not be
  71  *        necessary if the host is notified via another IRQ.
  72  */
  73 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  74 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  75 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  76
  77 /* EC commands */
  78 enum ec_command {
  79         ACPI_EC_COMMAND_READ = 0x80,
  80         ACPI_EC_COMMAND_WRITE = 0x81,
  81         ACPI_EC_BURST_ENABLE = 0x82,
  82         ACPI_EC_BURST_DISABLE = 0x83,
  83         ACPI_EC_COMMAND_QUERY = 0x84,
  84 };
  85
  86 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  87 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  88 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
  89 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  90                                          * when trying to clear the EC */
  91 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
  92
  93 enum {
  94         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
  95         EC_FLAGS_QUERY_PENDING,         /* Query is pending */
  96         EC_FLAGS_QUERY_GUARDING,        /* Guard for SCI_EVT check */
  97         EC_FLAGS_EVENT_HANDLER_INSTALLED,       /* Event handler installed */
  98         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
  99         EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
 100         EC_FLAGS_STARTED,               /* Driver is started */
 101         EC_FLAGS_STOPPED,               /* Driver is stopped */
 102         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 103 };
 104
 105 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 106 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 107
 108 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 109 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 110 module_param(ec_delay, uint, 0644);
 111 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 112
 113 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 114 module_param(ec_max_queries, uint, 0644);
 115 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 116
 117 static bool ec_busy_polling __read_mostly;
 118 module_param(ec_busy_polling, bool, 0644);
 119 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 120
 121 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 122 module_param(ec_polling_guard, uint, 0644);
 123 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 124
 125 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 126
 127 /*
 128  * If the number of false interrupts per one transaction exceeds
 129  * this threshold, will think there is a GPE storm happened and
 130  * will disable the GPE for normal transaction.
 131  */
 132 static unsigned int ec_storm_threshold  __read_mostly = 8;
 133 module_param(ec_storm_threshold, uint, 0644);
 134 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 135
 136 static bool ec_freeze_events __read_mostly = false;
 137 module_param(ec_freeze_events, bool, 0644);
 138 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 139
 140 static bool ec_no_wakeup __read_mostly;
 141 module_param(ec_no_wakeup, bool, 0644);
 142 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 143
 144 struct acpi_ec_query_handler {
 145         struct list_head node;
 146         acpi_ec_query_func func;
 147         acpi_handle handle;
 148         void *data;
 149         u8 query_bit;
 150         struct kref kref;
 151 };
 152
 153 struct transaction {
 154         const u8 *wdata;
 155         u8 *rdata;
 156         unsigned short irq_count;
 157         u8 command;
 158         u8 wi;
 159         u8 ri;
 160         u8 wlen;
 161         u8 rlen;
 162         u8 flags;
 163 };
 164
 165 struct acpi_ec_query {
 166         struct transaction transaction;
 167         struct work_struct work;
 168         struct acpi_ec_query_handler *handler;
 169 };
 170
 171 static int acpi_ec_query(struct acpi_ec *ec, u8 *data);
 172 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 173 static void acpi_ec_event_handler(struct work_struct *work);
 174 static void acpi_ec_event_processor(struct work_struct *work);
 175
 176 struct acpi_ec *first_ec;
 177 EXPORT_SYMBOL(first_ec);
 178
 179 static struct acpi_ec *boot_ec;
 180 static bool boot_ec_is_ecdt = false;
 181 static struct workqueue_struct *ec_wq;
 182 static struct workqueue_struct *ec_query_wq;
 183
 184 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 185 static int EC_FLAGS_IGNORE_DSDT_GPE; /* Needs ECDT GPE as correction setting */
 186 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 187
 188 /* --------------------------------------------------------------------------
 189  *                           Logging/Debugging
 190  * -------------------------------------------------------------------------- */
 191
 192 /*
 193  * Splitters used by the developers to track the boundary of the EC
 194  * handling processes.
 195  */
 196 #ifdef DEBUG
 197 #define EC_DBG_SEP      " "
 198 #define EC_DBG_DRV      "+++++"
 199 #define EC_DBG_STM      "====="
 200 #define EC_DBG_REQ      "*****"
 201 #define EC_DBG_EVT      "#####"
 202 #else
 203 #define EC_DBG_SEP      ""
 204 #define EC_DBG_DRV
 205 #define EC_DBG_STM
 206 #define EC_DBG_REQ
 207 #define EC_DBG_EVT
 208 #endif
 209
 210 #define ec_log_raw(fmt, ...) \
 211         pr_info(fmt "\n", ##__VA_ARGS__)
 212 #define ec_dbg_raw(fmt, ...) \
 213         pr_debug(fmt "\n", ##__VA_ARGS__)
 214 #define ec_log(filter, fmt, ...) \
 215         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 216 #define ec_dbg(filter, fmt, ...) \
 217         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 218
 219 #define ec_log_drv(fmt, ...) \
 220         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 221 #define ec_dbg_drv(fmt, ...) \
 222         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 223 #define ec_dbg_stm(fmt, ...) \
 224         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 225 #define ec_dbg_req(fmt, ...) \
 226         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 227 #define ec_dbg_evt(fmt, ...) \
 228         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 229 #define ec_dbg_ref(ec, fmt, ...) \
 230         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 231
 232 /* --------------------------------------------------------------------------
 233  *                           Device Flags
 234  * -------------------------------------------------------------------------- */
 235
 236 static bool acpi_ec_started(struct acpi_ec *ec)
 237 {
 238         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 239                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 240 }
 241
 242 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 243 {
 244         /*
 245          * There is an OSPM early stage logic. During the early stages
 246          * (boot/resume), OSPMs shouldn't enable the event handling, only
 247          * the EC transactions are allowed to be performed.
 248          */
 249         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 250                 return false;
 251         /*
 252          * However, disabling the event handling is experimental for late
 253          * stage (suspend), and is controlled by the boot parameter of
 254          * "ec_freeze_events":
 255          * 1. true:  The EC event handling is disabled before entering
 256          *           the noirq stage.
 257          * 2. false: The EC event handling is automatically disabled as
 258          *           soon as the EC driver is stopped.
 259          */
 260         if (ec_freeze_events)
 261                 return acpi_ec_started(ec);
 262         else
 263                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 264 }
 265
 266 static bool acpi_ec_flushed(struct acpi_ec *ec)
 267 {
 268         return ec->reference_count == 1;
 269 }
 270
 271 /* --------------------------------------------------------------------------
 272  *                           EC Registers
 273  * -------------------------------------------------------------------------- */
 274
 275 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 276 {
 277         u8 x = inb(ec->command_addr);
 278
 279         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 280                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 281                    x,
 282                    !!(x & ACPI_EC_FLAG_SCI),
 283                    !!(x & ACPI_EC_FLAG_BURST),
 284                    !!(x & ACPI_EC_FLAG_CMD),
 285                    !!(x & ACPI_EC_FLAG_IBF),
 286                    !!(x & ACPI_EC_FLAG_OBF));
 287         return x;
 288 }
 289
 290 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 291 {
 292         u8 x = inb(ec->data_addr);
 293
 294         ec->timestamp = jiffies;
 295         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 296         return x;
 297 }
 298
 299 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 300 {
 301         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 302         outb(command, ec->command_addr);
 303         ec->timestamp = jiffies;
 304 }
 305
 306 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 307 {
 308         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 309         outb(data, ec->data_addr);
 310         ec->timestamp = jiffies;
 311 }
 312
 313 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 314 static const char *acpi_ec_cmd_string(u8 cmd)
 315 {
 316         switch (cmd) {
 317         case 0x80:
 318                 return "RD_EC";
 319         case 0x81:
 320                 return "WR_EC";
 321         case 0x82:
 322                 return "BE_EC";
 323         case 0x83:
 324                 return "BD_EC";
 325         case 0x84:
 326                 return "QR_EC";
 327         }
 328         return "UNKNOWN";
 329 }
 330 #else
 331 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 332 #endif
 333
 334 /* --------------------------------------------------------------------------
 335  *                           GPE Registers
 336  * -------------------------------------------------------------------------- */
 337
 338 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 339 {
 340         acpi_event_status gpe_status = 0;
 341
 342         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 343         return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 344 }
 345
 346 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 347 {
 348         if (open)
 349                 acpi_enable_gpe(NULL, ec->gpe);
 350         else {
 351                 BUG_ON(ec->reference_count < 1);
 352                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 353         }
 354         if (acpi_ec_gpe_status_set(ec)) {
 355                 /*
 356                  * On some platforms, EN=1 writes cannot trigger GPE. So
 357                  * software need to manually trigger a pseudo GPE event on
 358                  * EN=1 writes.
 359                  */
 360                 ec_dbg_raw("Polling quirk");
 361                 advance_transaction(ec, false);
 362         }
 363 }
 364
 365 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 366 {
 367         if (close)
 368                 acpi_disable_gpe(NULL, ec->gpe);
 369         else {
 370                 BUG_ON(ec->reference_count < 1);
 371                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 372         }
 373 }
 374
 375 /* --------------------------------------------------------------------------
 376  *                           Transaction Management
 377  * -------------------------------------------------------------------------- */
 378
 379 static void acpi_ec_submit_request(struct acpi_ec *ec)
 380 {
 381         ec->reference_count++;
 382         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 383             ec->gpe >= 0 && ec->reference_count == 1)
 384                 acpi_ec_enable_gpe(ec, true);
 385 }
 386
 387 static void acpi_ec_complete_request(struct acpi_ec *ec)
 388 {
 389         bool flushed = false;
 390
 391         ec->reference_count--;
 392         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 393             ec->gpe >= 0 && ec->reference_count == 0)
 394                 acpi_ec_disable_gpe(ec, true);
 395         flushed = acpi_ec_flushed(ec);
 396         if (flushed)
 397                 wake_up(&ec->wait);
 398 }
 399
 400 static void acpi_ec_mask_events(struct acpi_ec *ec)
 401 {
 402         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 403                 if (ec->gpe >= 0)
 404                         acpi_ec_disable_gpe(ec, false);
 405                 else
 406                         disable_irq_nosync(ec->irq);
 407
 408                 ec_dbg_drv("Polling enabled");
 409                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 410         }
 411 }
 412
 413 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 414 {
 415         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 416                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 417                 if (ec->gpe >= 0)
 418                         acpi_ec_enable_gpe(ec, false);
 419                 else
 420                         enable_irq(ec->irq);
 421
 422                 ec_dbg_drv("Polling disabled");
 423         }
 424 }
 425
 426 /*
 427  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 428  *                                      the flush operation is not in
 429  *                                      progress
 430  * @ec: the EC device
 431  *
 432  * This function must be used before taking a new action that should hold
 433  * the reference count.  If this function returns false, then the action
 434  * must be discarded or it will prevent the flush operation from being
 435  * completed.
 436  */
 437 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 438 {
 439         if (!acpi_ec_started(ec))
 440                 return false;
 441         acpi_ec_submit_request(ec);
 442         return true;
 443 }
 444
 445 static void acpi_ec_submit_query(struct acpi_ec *ec)
 446 {
 447         acpi_ec_mask_events(ec);
 448         if (!acpi_ec_event_enabled(ec))
 449                 return;
 450         if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
 451                 ec_dbg_evt("Command(%s) submitted/blocked",
 452                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 453                 ec->nr_pending_queries++;
 454                 queue_work(ec_wq, &ec->work);
 455         }
 456 }
 457
 458 static void acpi_ec_complete_query(struct acpi_ec *ec)
 459 {
 460         if (test_and_clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
 461                 ec_dbg_evt("Command(%s) unblocked",
 462                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 463         acpi_ec_unmask_events(ec);
 464 }
 465
 466 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 467 {
 468         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 469                 ec_log_drv("event unblocked");
 470         /*
 471          * Unconditionally invoke this once after enabling the event
 472          * handling mechanism to detect the pending events.
 473          */
 474         advance_transaction(ec, false);
 475 }
 476
 477 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 478 {
 479         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 480                 ec_log_drv("event blocked");
 481 }
 482
 483 /*
 484  * Process _Q events that might have accumulated in the EC.
 485  * Run with locked ec mutex.
 486  */
 487 static void acpi_ec_clear(struct acpi_ec *ec)
 488 {
 489         int i, status;
 490         u8 value = 0;
 491
 492         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 493                 status = acpi_ec_query(ec, &value);
 494                 if (status || !value)
 495                         break;
 496         }
 497         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 498                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 499         else
 500                 pr_info("%d stale EC events cleared\n", i);
 501 }
 502
 503 static void acpi_ec_enable_event(struct acpi_ec *ec)
 504 {
 505         unsigned long flags;
 506
 507         spin_lock_irqsave(&ec->lock, flags);
 508         if (acpi_ec_started(ec))
 509                 __acpi_ec_enable_event(ec);
 510         spin_unlock_irqrestore(&ec->lock, flags);
 511
 512         /* Drain additional events if hardware requires that */
 513         if (EC_FLAGS_CLEAR_ON_RESUME)
 514                 acpi_ec_clear(ec);
 515 }
 516
 517 #ifdef CONFIG_PM_SLEEP
 518 static void __acpi_ec_flush_work(void)
 519 {
 520         drain_workqueue(ec_wq); /* flush ec->work */
 521         flush_workqueue(ec_query_wq); /* flush queries */
 522 }
 523
 524 static void acpi_ec_disable_event(struct acpi_ec *ec)
 525 {
 526         unsigned long flags;
 527
 528         spin_lock_irqsave(&ec->lock, flags);
 529         __acpi_ec_disable_event(ec);
 530         spin_unlock_irqrestore(&ec->lock, flags);
 531
 532         /*
 533          * When ec_freeze_events is true, we need to flush events in
 534          * the proper position before entering the noirq stage.
 535          */
 536         __acpi_ec_flush_work();
 537 }
 538
 539 void acpi_ec_flush_work(void)
 540 {
 541         /* Without ec_wq there is nothing to flush. */
 542         if (!ec_wq)
 543                 return;
 544
 545         __acpi_ec_flush_work();
 546 }
 547 #endif /* CONFIG_PM_SLEEP */
 548
 549 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 550 {
 551         bool guarded = true;
 552         unsigned long flags;
 553
 554         spin_lock_irqsave(&ec->lock, flags);
 555         /*
 556          * If firmware SCI_EVT clearing timing is "event", we actually
 557          * don't know when the SCI_EVT will be cleared by firmware after
 558          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 559          * acceptable period.
 560          *
 561          * The guarding period begins when EC_FLAGS_QUERY_PENDING is
 562          * flagged, which means SCI_EVT check has just been performed.
 563          * But if the current transaction is ACPI_EC_COMMAND_QUERY, the
 564          * guarding should have already been performed (via
 565          * EC_FLAGS_QUERY_GUARDING) and should not be applied so that the
 566          * ACPI_EC_COMMAND_QUERY transaction can be transitioned into
 567          * ACPI_EC_COMMAND_POLL state immediately.
 568          */
 569         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
 570             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY ||
 571             !test_bit(EC_FLAGS_QUERY_PENDING, &ec->flags) ||
 572             (ec->curr && ec->curr->command == ACPI_EC_COMMAND_QUERY))
 573                 guarded = false;
 574         spin_unlock_irqrestore(&ec->lock, flags);
 575         return guarded;
 576 }
 577
 578 static int ec_transaction_polled(struct acpi_ec *ec)
 579 {
 580         unsigned long flags;
 581         int ret = 0;
 582
 583         spin_lock_irqsave(&ec->lock, flags);
 584         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 585                 ret = 1;
 586         spin_unlock_irqrestore(&ec->lock, flags);
 587         return ret;
 588 }
 589
 590 static int ec_transaction_completed(struct acpi_ec *ec)
 591 {
 592         unsigned long flags;
 593         int ret = 0;
 594
 595         spin_lock_irqsave(&ec->lock, flags);
 596         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 597                 ret = 1;
 598         spin_unlock_irqrestore(&ec->lock, flags);
 599         return ret;
 600 }
 601
 602 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 603 {
 604         ec->curr->flags |= flag;
 605         if (ec->curr->command == ACPI_EC_COMMAND_QUERY) {
 606                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS &&
 607                     flag == ACPI_EC_COMMAND_POLL)
 608                         acpi_ec_complete_query(ec);
 609                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY &&
 610                     flag == ACPI_EC_COMMAND_COMPLETE)
 611                         acpi_ec_complete_query(ec);
 612                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 613                     flag == ACPI_EC_COMMAND_COMPLETE)
 614                         set_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 615         }
 616 }
 617
 618 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 619 {
 620         if (t->irq_count < ec_storm_threshold)
 621                 ++t->irq_count;
 622
 623         /* Trigger if the threshold is 0 too. */
 624         if (t->irq_count == ec_storm_threshold)
 625                 acpi_ec_mask_events(ec);
 626 }
 627
 628 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 629 {
 630         struct transaction *t = ec->curr;
 631         bool wakeup = false;
 632         u8 status;
 633
 634         ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 635
 636         /*
 637          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
 638          * changes to always trigger a GPE interrupt.
 639          *
 640          * GPE STS is a W1C register, which means:
 641          *
 642          * 1. Software can clear it without worrying about clearing the other
 643          *    GPEs' STS bits when the hardware sets them in parallel.
 644          *
 645          * 2. As long as software can ensure only clearing it when it is set,
 646          *    hardware won't set it in parallel.
 647          */
 648         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
 649                 acpi_clear_gpe(NULL, ec->gpe);
 650
 651         status = acpi_ec_read_status(ec);
 652
 653         /*
 654          * Another IRQ or a guarded polling mode advancement is detected,
 655          * the next QR_EC submission is then allowed.
 656          */
 657         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 658                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 659                     (!ec->nr_pending_queries ||
 660                      test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) {
 661                         clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags);
 662                         acpi_ec_complete_query(ec);
 663                 }
 664                 if (!t)
 665                         goto out;
 666         }
 667
 668         if (t->flags & ACPI_EC_COMMAND_POLL) {
 669                 if (t->wlen > t->wi) {
 670                         if (!(status & ACPI_EC_FLAG_IBF))
 671                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 672                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 673                                 acpi_ec_spurious_interrupt(ec, t);
 674                 } else if (t->rlen > t->ri) {
 675                         if (status & ACPI_EC_FLAG_OBF) {
 676                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 677                                 if (t->rlen == t->ri) {
 678                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 679                                         wakeup = true;
 680                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 681                                                 ec_dbg_evt("Command(%s) completed by hardware",
 682                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 683                                 }
 684                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 685                                 acpi_ec_spurious_interrupt(ec, t);
 686                         }
 687                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 688                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 689                         wakeup = true;
 690                 }
 691         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 692                 acpi_ec_write_cmd(ec, t->command);
 693                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 694         }
 695
 696 out:
 697         if (status & ACPI_EC_FLAG_SCI)
 698                 acpi_ec_submit_query(ec);
 699
 700         if (wakeup && interrupt)
 701                 wake_up(&ec->wait);
 702 }
 703
 704 static void start_transaction(struct acpi_ec *ec)
 705 {
 706         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 707         ec->curr->flags = 0;
 708 }
 709
 710 static int ec_guard(struct acpi_ec *ec)
 711 {
 712         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 713         unsigned long timeout = ec->timestamp + guard;
 714
 715         /* Ensure guarding period before polling EC status */
 716         do {
 717                 if (ec->busy_polling) {
 718                         /* Perform busy polling */
 719                         if (ec_transaction_completed(ec))
 720                                 return 0;
 721                         udelay(jiffies_to_usecs(guard));
 722                 } else {
 723                         /*
 724                          * Perform wait polling
 725                          * 1. Wait the transaction to be completed by the
 726                          *    GPE handler after the transaction enters
 727                          *    ACPI_EC_COMMAND_POLL state.
 728                          * 2. A special guarding logic is also required
 729                          *    for event clearing mode "event" before the
 730                          *    transaction enters ACPI_EC_COMMAND_POLL
 731                          *    state.
 732                          */
 733                         if (!ec_transaction_polled(ec) &&
 734                             !acpi_ec_guard_event(ec))
 735                                 break;
 736                         if (wait_event_timeout(ec->wait,
 737                                                ec_transaction_completed(ec),
 738                                                guard))
 739                                 return 0;
 740                 }
 741         } while (time_before(jiffies, timeout));
 742         return -ETIME;
 743 }
 744
 745 static int ec_poll(struct acpi_ec *ec)
 746 {
 747         unsigned long flags;
 748         int repeat = 5; /* number of command restarts */
 749
 750         while (repeat--) {
 751                 unsigned long delay = jiffies +
 752                         msecs_to_jiffies(ec_delay);
 753                 do {
 754                         if (!ec_guard(ec))
 755                                 return 0;
 756                         spin_lock_irqsave(&ec->lock, flags);
 757                         advance_transaction(ec, false);
 758                         spin_unlock_irqrestore(&ec->lock, flags);
 759                 } while (time_before(jiffies, delay));
 760                 pr_debug("controller reset, restart transaction\n");
 761                 spin_lock_irqsave(&ec->lock, flags);
 762                 start_transaction(ec);
 763                 spin_unlock_irqrestore(&ec->lock, flags);
 764         }
 765         return -ETIME;
 766 }
 767
 768 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 769                                         struct transaction *t)
 770 {
 771         unsigned long tmp;
 772         int ret = 0;
 773
 774         /* start transaction */
 775         spin_lock_irqsave(&ec->lock, tmp);
 776         /* Enable GPE for command processing (IBF=0/OBF=1) */
 777         if (!acpi_ec_submit_flushable_request(ec)) {
 778                 ret = -EINVAL;
 779                 goto unlock;
 780         }
 781         ec_dbg_ref(ec, "Increase command");
 782         /* following two actions should be kept atomic */
 783         ec->curr = t;
 784         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 785         start_transaction(ec);
 786         spin_unlock_irqrestore(&ec->lock, tmp);
 787
 788         ret = ec_poll(ec);
 789
 790         spin_lock_irqsave(&ec->lock, tmp);
 791         if (t->irq_count == ec_storm_threshold)
 792                 acpi_ec_unmask_events(ec);
 793         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 794         ec->curr = NULL;
 795         /* Disable GPE for command processing (IBF=0/OBF=1) */
 796         acpi_ec_complete_request(ec);
 797         ec_dbg_ref(ec, "Decrease command");
 798 unlock:
 799         spin_unlock_irqrestore(&ec->lock, tmp);
 800         return ret;
 801 }
 802
 803 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 804 {
 805         int status;
 806         u32 glk;
 807
 808         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 809                 return -EINVAL;
 810         if (t->rdata)
 811                 memset(t->rdata, 0, t->rlen);
 812
 813         mutex_lock(&ec->mutex);
 814         if (ec->global_lock) {
 815                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 816                 if (ACPI_FAILURE(status)) {
 817                         status = -ENODEV;
 818                         goto unlock;
 819                 }
 820         }
 821
 822         status = acpi_ec_transaction_unlocked(ec, t);
 823
 824         if (ec->global_lock)
 825                 acpi_release_global_lock(glk);
 826 unlock:
 827         mutex_unlock(&ec->mutex);
 828         return status;
 829 }
 830
 831 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 832 {
 833         u8 d;
 834         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 835                                 .wdata = NULL, .rdata = &d,
 836                                 .wlen = 0, .rlen = 1};
 837
 838         return acpi_ec_transaction(ec, &t);
 839 }
 840
 841 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 842 {
 843         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 844                                 .wdata = NULL, .rdata = NULL,
 845                                 .wlen = 0, .rlen = 0};
 846
 847         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 848                                 acpi_ec_transaction(ec, &t) : 0;
 849 }
 850
 851 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 852 {
 853         int result;
 854         u8 d;
 855         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 856                                 .wdata = &address, .rdata = &d,
 857                                 .wlen = 1, .rlen = 1};
 858
 859         result = acpi_ec_transaction(ec, &t);
 860         *data = d;
 861         return result;
 862 }
 863
 864 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 865 {
 866         u8 wdata[2] = { address, data };
 867         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 868                                 .wdata = wdata, .rdata = NULL,
 869                                 .wlen = 2, .rlen = 0};
 870
 871         return acpi_ec_transaction(ec, &t);
 872 }
 873
 874 int ec_read(u8 addr, u8 *val)
 875 {
 876         int err;
 877         u8 temp_data;
 878
 879         if (!first_ec)
 880                 return -ENODEV;
 881
 882         err = acpi_ec_read(first_ec, addr, &temp_data);
 883
 884         if (!err) {
 885                 *val = temp_data;
 886                 return 0;
 887         }
 888         return err;
 889 }
 890 EXPORT_SYMBOL(ec_read);
 891
 892 int ec_write(u8 addr, u8 val)
 893 {
 894         int err;
 895
 896         if (!first_ec)
 897                 return -ENODEV;
 898
 899         err = acpi_ec_write(first_ec, addr, val);
 900
 901         return err;
 902 }
 903 EXPORT_SYMBOL(ec_write);
 904
 905 int ec_transaction(u8 command,
 906                    const u8 *wdata, unsigned wdata_len,
 907                    u8 *rdata, unsigned rdata_len)
 908 {
 909         struct transaction t = {.command = command,
 910                                 .wdata = wdata, .rdata = rdata,
 911                                 .wlen = wdata_len, .rlen = rdata_len};
 912
 913         if (!first_ec)
 914                 return -ENODEV;
 915
 916         return acpi_ec_transaction(first_ec, &t);
 917 }
 918 EXPORT_SYMBOL(ec_transaction);
 919
 920 /* Get the handle to the EC device */
 921 acpi_handle ec_get_handle(void)
 922 {
 923         if (!first_ec)
 924                 return NULL;
 925         return first_ec->handle;
 926 }
 927 EXPORT_SYMBOL(ec_get_handle);
 928
 929 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 930 {
 931         unsigned long flags;
 932
 933         spin_lock_irqsave(&ec->lock, flags);
 934         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 935                 ec_dbg_drv("Starting EC");
 936                 /* Enable GPE for event processing (SCI_EVT=1) */
 937                 if (!resuming) {
 938                         acpi_ec_submit_request(ec);
 939                         ec_dbg_ref(ec, "Increase driver");
 940                 }
 941                 ec_log_drv("EC started");
 942         }
 943         spin_unlock_irqrestore(&ec->lock, flags);
 944 }
 945
 946 static bool acpi_ec_stopped(struct acpi_ec *ec)
 947 {
 948         unsigned long flags;
 949         bool flushed;
 950
 951         spin_lock_irqsave(&ec->lock, flags);
 952         flushed = acpi_ec_flushed(ec);
 953         spin_unlock_irqrestore(&ec->lock, flags);
 954         return flushed;
 955 }
 956
 957 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 958 {
 959         unsigned long flags;
 960
 961         spin_lock_irqsave(&ec->lock, flags);
 962         if (acpi_ec_started(ec)) {
 963                 ec_dbg_drv("Stopping EC");
 964                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 965                 spin_unlock_irqrestore(&ec->lock, flags);
 966                 wait_event(ec->wait, acpi_ec_stopped(ec));
 967                 spin_lock_irqsave(&ec->lock, flags);
 968                 /* Disable GPE for event processing (SCI_EVT=1) */
 969                 if (!suspending) {
 970                         acpi_ec_complete_request(ec);
 971                         ec_dbg_ref(ec, "Decrease driver");
 972                 } else if (!ec_freeze_events)
 973                         __acpi_ec_disable_event(ec);
 974                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 975                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 976                 ec_log_drv("EC stopped");
 977         }
 978         spin_unlock_irqrestore(&ec->lock, flags);
 979 }
 980
 981 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 982 {
 983         unsigned long flags;
 984
 985         spin_lock_irqsave(&ec->lock, flags);
 986         ec->busy_polling = true;
 987         ec->polling_guard = 0;
 988         ec_log_drv("interrupt blocked");
 989         spin_unlock_irqrestore(&ec->lock, flags);
 990 }
 991
 992 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
 993 {
 994         unsigned long flags;
 995
 996         spin_lock_irqsave(&ec->lock, flags);
 997         ec->busy_polling = ec_busy_polling;
 998         ec->polling_guard = ec_polling_guard;
 999         ec_log_drv("interrupt unblocked");
1000         spin_unlock_irqrestore(&ec->lock, flags);
1001 }
1002
1003 void acpi_ec_block_transactions(void)
1004 {
1005         struct acpi_ec *ec = first_ec;
1006
1007         if (!ec)
1008                 return;
1009
1010         mutex_lock(&ec->mutex);
1011         /* Prevent transactions from being carried out */
1012         acpi_ec_stop(ec, true);
1013         mutex_unlock(&ec->mutex);
1014 }
1015
1016 void acpi_ec_unblock_transactions(void)
1017 {
1018         /*
1019          * Allow transactions to happen again (this function is called from
1020          * atomic context during wakeup, so we don't need to acquire the mutex).
1021          */
1022         if (first_ec)
1023                 acpi_ec_start(first_ec, true);
1024 }
1025
1026 /* --------------------------------------------------------------------------
1027                                 Event Management
1028    -------------------------------------------------------------------------- */
1029 static struct acpi_ec_query_handler *
1030 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1031 {
1032         struct acpi_ec_query_handler *handler;
1033
1034         mutex_lock(&ec->mutex);
1035         list_for_each_entry(handler, &ec->list, node) {
1036                 if (value == handler->query_bit) {
1037                         kref_get(&handler->kref);
1038                         mutex_unlock(&ec->mutex);
1039                         return handler;
1040                 }
1041         }
1042         mutex_unlock(&ec->mutex);
1043         return NULL;
1044 }
1045
1046 static void acpi_ec_query_handler_release(struct kref *kref)
1047 {
1048         struct acpi_ec_query_handler *handler =
1049                 container_of(kref, struct acpi_ec_query_handler, kref);
1050
1051         kfree(handler);
1052 }
1053
1054 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1055 {
1056         kref_put(&handler->kref, acpi_ec_query_handler_release);
1057 }
1058
1059 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1060                               acpi_handle handle, acpi_ec_query_func func,
1061                               void *data)
1062 {
1063         struct acpi_ec_query_handler *handler =
1064             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1065
1066         if (!handler)
1067                 return -ENOMEM;
1068
1069         handler->query_bit = query_bit;
1070         handler->handle = handle;
1071         handler->func = func;
1072         handler->data = data;
1073         mutex_lock(&ec->mutex);
1074         kref_init(&handler->kref);
1075         list_add(&handler->node, &ec->list);
1076         mutex_unlock(&ec->mutex);
1077         return 0;
1078 }
1079 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1080
1081 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1082                                           bool remove_all, u8 query_bit)
1083 {
1084         struct acpi_ec_query_handler *handler, *tmp;
1085         LIST_HEAD(free_list);
1086
1087         mutex_lock(&ec->mutex);
1088         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1089                 if (remove_all || query_bit == handler->query_bit) {
1090                         list_del_init(&handler->node);
1091                         list_add(&handler->node, &free_list);
1092                 }
1093         }
1094         mutex_unlock(&ec->mutex);
1095         list_for_each_entry_safe(handler, tmp, &free_list, node)
1096                 acpi_ec_put_query_handler(handler);
1097 }
1098
1099 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1100 {
1101         acpi_ec_remove_query_handlers(ec, false, query_bit);
1102 }
1103 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1104
1105 static struct acpi_ec_query *acpi_ec_create_query(u8 *pval)
1106 {
1107         struct acpi_ec_query *q;
1108         struct transaction *t;
1109
1110         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1111         if (!q)
1112                 return NULL;
1113         INIT_WORK(&q->work, acpi_ec_event_processor);
1114         t = &q->transaction;
1115         t->command = ACPI_EC_COMMAND_QUERY;
1116         t->rdata = pval;
1117         t->rlen = 1;
1118         return q;
1119 }
1120
1121 static void acpi_ec_delete_query(struct acpi_ec_query *q)
1122 {
1123         if (q) {
1124                 if (q->handler)
1125                         acpi_ec_put_query_handler(q->handler);
1126                 kfree(q);
1127         }
1128 }
1129
1130 static void acpi_ec_event_processor(struct work_struct *work)
1131 {
1132         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1133         struct acpi_ec_query_handler *handler = q->handler;
1134
1135         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1136         if (handler->func)
1137                 handler->func(handler->data);
1138         else if (handler->handle)
1139                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1140         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1141         acpi_ec_delete_query(q);
1142 }
1143
1144 static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
1145 {
1146         u8 value = 0;
1147         int result;
1148         struct acpi_ec_query *q;
1149
1150         q = acpi_ec_create_query(&value);
1151         if (!q)
1152                 return -ENOMEM;
1153
1154         /*
1155          * Query the EC to find out which _Qxx method we need to evaluate.
1156          * Note that successful completion of the query causes the ACPI_EC_SCI
1157          * bit to be cleared (and thus clearing the interrupt source).
1158          */
1159         result = acpi_ec_transaction(ec, &q->transaction);
1160         if (!value)
1161                 result = -ENODATA;
1162         if (result)
1163                 goto err_exit;
1164
1165         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1166         if (!q->handler) {
1167                 result = -ENODATA;
1168                 goto err_exit;
1169         }
1170
1171         /*
1172          * It is reported that _Qxx are evaluated in a parallel way on
1173          * Windows:
1174          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1175          *
1176          * Put this log entry before schedule_work() in order to make
1177          * it appearing before any other log entries occurred during the
1178          * work queue execution.
1179          */
1180         ec_dbg_evt("Query(0x%02x) scheduled", value);
1181         if (!queue_work(ec_query_wq, &q->work)) {
1182                 ec_dbg_evt("Query(0x%02x) overlapped", value);
1183                 result = -EBUSY;
1184         }
1185
1186 err_exit:
1187         if (result)
1188                 acpi_ec_delete_query(q);
1189         if (data)
1190                 *data = value;
1191         return result;
1192 }
1193
1194 static void acpi_ec_check_event(struct acpi_ec *ec)
1195 {
1196         unsigned long flags;
1197
1198         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1199                 if (ec_guard(ec)) {
1200                         spin_lock_irqsave(&ec->lock, flags);
1201                         /*
1202                          * Take care of the SCI_EVT unless no one else is
1203                          * taking care of it.
1204                          */
1205                         if (!ec->curr)
1206                                 advance_transaction(ec, false);
1207                         spin_unlock_irqrestore(&ec->lock, flags);
1208                 }
1209         }
1210 }
1211
1212 static void acpi_ec_event_handler(struct work_struct *work)
1213 {
1214         unsigned long flags;
1215         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1216
1217         ec_dbg_evt("Event started");
1218
1219         spin_lock_irqsave(&ec->lock, flags);
1220         while (ec->nr_pending_queries) {
1221                 spin_unlock_irqrestore(&ec->lock, flags);
1222                 (void)acpi_ec_query(ec, NULL);
1223                 spin_lock_irqsave(&ec->lock, flags);
1224                 ec->nr_pending_queries--;
1225                 /*
1226                  * Before exit, make sure that this work item can be
1227                  * scheduled again. There might be QR_EC failures, leaving
1228                  * EC_FLAGS_QUERY_PENDING uncleared and preventing this work
1229                  * item from being scheduled again.
1230                  */
1231                 if (!ec->nr_pending_queries) {
1232                         if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS ||
1233                             ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY)
1234                                 acpi_ec_complete_query(ec);
1235                 }
1236         }
1237         spin_unlock_irqrestore(&ec->lock, flags);
1238
1239         ec_dbg_evt("Event stopped");
1240
1241         acpi_ec_check_event(ec);
1242 }
1243
1244 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1245 {
1246         unsigned long flags;
1247
1248         spin_lock_irqsave(&ec->lock, flags);
1249         advance_transaction(ec, true);
1250         spin_unlock_irqrestore(&ec->lock, flags);
1251 }
1252
1253 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1254                                u32 gpe_number, void *data)
1255 {
1256         acpi_ec_handle_interrupt(data);
1257         return ACPI_INTERRUPT_HANDLED;
1258 }
1259
1260 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1261 {
1262         acpi_ec_handle_interrupt(data);
1263         return IRQ_HANDLED;
1264 }
1265
1266 /* --------------------------------------------------------------------------
1267  *                           Address Space Management
1268  * -------------------------------------------------------------------------- */
1269
1270 static acpi_status
1271 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1272                       u32 bits, u64 *value64,
1273                       void *handler_context, void *region_context)
1274 {
1275         struct acpi_ec *ec = handler_context;
1276         int result = 0, i, bytes = bits / 8;
1277         u8 *value = (u8 *)value64;
1278
1279         if ((address > 0xFF) || !value || !handler_context)
1280                 return AE_BAD_PARAMETER;
1281
1282         if (function != ACPI_READ && function != ACPI_WRITE)
1283                 return AE_BAD_PARAMETER;
1284
1285         if (ec->busy_polling || bits > 8)
1286                 acpi_ec_burst_enable(ec);
1287
1288         for (i = 0; i < bytes; ++i, ++address, ++value)
1289                 result = (function == ACPI_READ) ?
1290                         acpi_ec_read(ec, address, value) :
1291                         acpi_ec_write(ec, address, *value);
1292
1293         if (ec->busy_polling || bits > 8)
1294                 acpi_ec_burst_disable(ec);
1295
1296         switch (result) {
1297         case -EINVAL:
1298                 return AE_BAD_PARAMETER;
1299         case -ENODEV:
1300                 return AE_NOT_FOUND;
1301         case -ETIME:
1302                 return AE_TIME;
1303         default:
1304                 return AE_OK;
1305         }
1306 }
1307
1308 /* --------------------------------------------------------------------------
1309  *                             Driver Interface
1310  * -------------------------------------------------------------------------- */
1311
1312 static acpi_status
1313 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1314
1315 static void acpi_ec_free(struct acpi_ec *ec)
1316 {
1317         if (first_ec == ec)
1318                 first_ec = NULL;
1319         if (boot_ec == ec)
1320                 boot_ec = NULL;
1321         kfree(ec);
1322 }
1323
1324 static struct acpi_ec *acpi_ec_alloc(void)
1325 {
1326         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1327
1328         if (!ec)
1329                 return NULL;
1330         mutex_init(&ec->mutex);
1331         init_waitqueue_head(&ec->wait);
1332         INIT_LIST_HEAD(&ec->list);
1333         spin_lock_init(&ec->lock);
1334         INIT_WORK(&ec->work, acpi_ec_event_handler);
1335         ec->timestamp = jiffies;
1336         ec->busy_polling = true;
1337         ec->polling_guard = 0;
1338         ec->gpe = -1;
1339         ec->irq = -1;
1340         return ec;
1341 }
1342
1343 static acpi_status
1344 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1345                                void *context, void **return_value)
1346 {
1347         char node_name[5];
1348         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1349         struct acpi_ec *ec = context;
1350         int value = 0;
1351         acpi_status status;
1352
1353         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1354
1355         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1356                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1357         return AE_OK;
1358 }
1359
1360 static acpi_status
1361 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1362 {
1363         acpi_status status;
1364         unsigned long long tmp = 0;
1365         struct acpi_ec *ec = context;
1366
1367         /* clear addr values, ec_parse_io_ports depend on it */
1368         ec->command_addr = ec->data_addr = 0;
1369
1370         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1371                                      ec_parse_io_ports, ec);
1372         if (ACPI_FAILURE(status))
1373                 return status;
1374         if (ec->data_addr == 0 || ec->command_addr == 0)
1375                 return AE_OK;
1376
1377         if (boot_ec && boot_ec_is_ecdt && EC_FLAGS_IGNORE_DSDT_GPE) {
1378                 /*
1379                  * Always inherit the GPE number setting from the ECDT
1380                  * EC.
1381                  */
1382                 ec->gpe = boot_ec->gpe;
1383         } else {
1384                 /* Get GPE bit assignment (EC events). */
1385                 /* TODO: Add support for _GPE returning a package */
1386                 status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1387                 if (ACPI_SUCCESS(status))
1388                         ec->gpe = tmp;
1389
1390                 /*
1391                  * Errors are non-fatal, allowing for ACPI Reduced Hardware
1392                  * platforms which use GpioInt instead of GPE.
1393                  */
1394         }
1395         /* Use the global lock for all EC transactions? */
1396         tmp = 0;
1397         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1398         ec->global_lock = tmp;
1399         ec->handle = handle;
1400         return AE_CTRL_TERMINATE;
1401 }
1402
1403 static bool install_gpe_event_handler(struct acpi_ec *ec)
1404 {
1405         acpi_status status;
1406
1407         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1408                                               ACPI_GPE_EDGE_TRIGGERED,
1409                                               &acpi_ec_gpe_handler, ec);
1410         if (ACPI_FAILURE(status))
1411                 return false;
1412
1413         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1414                 acpi_ec_enable_gpe(ec, true);
1415
1416         return true;
1417 }
1418
1419 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1420 {
1421         return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1422                            "ACPI EC", ec) >= 0;
1423 }
1424
1425 /**
1426  * ec_install_handlers - Install service callbacks and register query methods.
1427  * @ec: Target EC.
1428  * @device: ACPI device object corresponding to @ec.
1429  *
1430  * Install a handler for the EC address space type unless it has been installed
1431  * already.  If @device is not NULL, also look for EC query methods in the
1432  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1433  * handler for the EC, if possible.
1434  *
1435  * Return:
1436  * -ENODEV if the address space handler cannot be installed, which means
1437  *  "unable to handle transactions",
1438  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1439  * or 0 (success) otherwise.
1440  */
1441 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device)
1442 {
1443         acpi_status status;
1444
1445         acpi_ec_start(ec, false);
1446
1447         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1448                 acpi_ec_enter_noirq(ec);
1449                 status = acpi_install_address_space_handler(ec->handle,
1450                                                             ACPI_ADR_SPACE_EC,
1451                                                             &acpi_ec_space_handler,
1452                                                             NULL, ec);
1453                 if (ACPI_FAILURE(status)) {
1454                         acpi_ec_stop(ec, false);
1455                         return -ENODEV;
1456                 }
1457                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1458         }
1459
1460         if (!device)
1461                 return 0;
1462
1463         if (ec->gpe < 0) {
1464                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1465                 int irq = acpi_dev_gpio_irq_get(device, 0);
1466                 /*
1467                  * Bail out right away for deferred probing or complete the
1468                  * initialization regardless of any other errors.
1469                  */
1470                 if (irq == -EPROBE_DEFER)
1471                         return -EPROBE_DEFER;
1472                 else if (irq >= 0)
1473                         ec->irq = irq;
1474         }
1475
1476         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1477                 /* Find and register all query methods */
1478                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1479                                     acpi_ec_register_query_methods,
1480                                     NULL, ec, NULL);
1481                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1482         }
1483         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1484                 bool ready = false;
1485
1486                 if (ec->gpe >= 0)
1487                         ready = install_gpe_event_handler(ec);
1488                 else if (ec->irq >= 0)
1489                         ready = install_gpio_irq_event_handler(ec);
1490
1491                 if (ready) {
1492                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1493                         acpi_ec_leave_noirq(ec);
1494                 }
1495                 /*
1496                  * Failures to install an event handler are not fatal, because
1497                  * the EC can be polled for events.
1498                  */
1499         }
1500         /* EC is fully operational, allow queries */
1501         acpi_ec_enable_event(ec);
1502
1503         return 0;
1504 }
1505
1506 static void ec_remove_handlers(struct acpi_ec *ec)
1507 {
1508         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1509                 if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
1510                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1511                         pr_err("failed to remove space handler\n");
1512                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1513         }
1514
1515         /*
1516          * Stops handling the EC transactions after removing the operation
1517          * region handler. This is required because _REG(DISCONNECT)
1518          * invoked during the removal can result in new EC transactions.
1519          *
1520          * Flushes the EC requests and thus disables the GPE before
1521          * removing the GPE handler. This is required by the current ACPICA
1522          * GPE core. ACPICA GPE core will automatically disable a GPE when
1523          * it is indicated but there is no way to handle it. So the drivers
1524          * must disable the GPEs prior to removing the GPE handlers.
1525          */
1526         acpi_ec_stop(ec, false);
1527
1528         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1529                 if (ec->gpe >= 0 &&
1530                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1531                                  &acpi_ec_gpe_handler)))
1532                         pr_err("failed to remove gpe handler\n");
1533
1534                 if (ec->irq >= 0)
1535                         free_irq(ec->irq, ec);
1536
1537                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1538         }
1539         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1540                 acpi_ec_remove_query_handlers(ec, true, 0);
1541                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1542         }
1543 }
1544
1545 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device)
1546 {
1547         int ret;
1548
1549         ret = ec_install_handlers(ec, device);
1550         if (ret)
1551                 return ret;
1552
1553         /* First EC capable of handling transactions */
1554         if (!first_ec)
1555                 first_ec = ec;
1556
1557         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1558                 ec->data_addr);
1559
1560         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1561                 if (ec->gpe >= 0)
1562                         pr_info("GPE=0x%x\n", ec->gpe);
1563                 else
1564                         pr_info("IRQ=%d\n", ec->irq);
1565         }
1566
1567         return ret;
1568 }
1569
1570 static int acpi_ec_add(struct acpi_device *device)
1571 {
1572         struct acpi_ec *ec;
1573         int ret;
1574
1575         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1576         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1577
1578         if (boot_ec && (boot_ec->handle == device->handle ||
1579             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1580                 /* Fast path: this device corresponds to the boot EC. */
1581                 ec = boot_ec;
1582         } else {
1583                 acpi_status status;
1584
1585                 ec = acpi_ec_alloc();
1586                 if (!ec)
1587                         return -ENOMEM;
1588
1589                 status = ec_parse_device(device->handle, 0, ec, NULL);
1590                 if (status != AE_CTRL_TERMINATE) {
1591                         ret = -EINVAL;
1592                         goto err;
1593                 }
1594
1595                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1596                     ec->data_addr == boot_ec->data_addr) {
1597                         /*
1598                          * Trust PNP0C09 namespace location rather than
1599                          * ECDT ID. But trust ECDT GPE rather than _GPE
1600                          * because of ASUS quirks, so do not change
1601                          * boot_ec->gpe to ec->gpe.
1602                          */
1603                         boot_ec->handle = ec->handle;
1604                         acpi_handle_debug(ec->handle, "duplicated.\n");
1605                         acpi_ec_free(ec);
1606                         ec = boot_ec;
1607                 }
1608         }
1609
1610         ret = acpi_ec_setup(ec, device);
1611         if (ret)
1612                 goto err;
1613
1614         if (ec == boot_ec)
1615                 acpi_handle_info(boot_ec->handle,
1616                                  "Boot %s EC initialization complete\n",
1617                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1618
1619         acpi_handle_info(ec->handle,
1620                          "EC: Used to handle transactions and events\n");
1621
1622         device->driver_data = ec;
1623
1624         ret = !!request_region(ec->data_addr, 1, "EC data");
1625         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1626         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1627         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1628
1629         /* Reprobe devices depending on the EC */
1630         acpi_walk_dep_device_list(ec->handle);
1631
1632         acpi_handle_debug(ec->handle, "enumerated.\n");
1633         return 0;
1634
1635 err:
1636         if (ec != boot_ec)
1637                 acpi_ec_free(ec);
1638
1639         return ret;
1640 }
1641
1642 static int acpi_ec_remove(struct acpi_device *device)
1643 {
1644         struct acpi_ec *ec;
1645
1646         if (!device)
1647                 return -EINVAL;
1648
1649         ec = acpi_driver_data(device);
1650         release_region(ec->data_addr, 1);
1651         release_region(ec->command_addr, 1);
1652         device->driver_data = NULL;
1653         if (ec != boot_ec) {
1654                 ec_remove_handlers(ec);
1655                 acpi_ec_free(ec);
1656         }
1657         return 0;
1658 }
1659
1660 static acpi_status
1661 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1662 {
1663         struct acpi_ec *ec = context;
1664
1665         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1666                 return AE_OK;
1667
1668         /*
1669          * The first address region returned is the data port, and
1670          * the second address region returned is the status/command
1671          * port.
1672          */
1673         if (ec->data_addr == 0)
1674                 ec->data_addr = resource->data.io.minimum;
1675         else if (ec->command_addr == 0)
1676                 ec->command_addr = resource->data.io.minimum;
1677         else
1678                 return AE_CTRL_TERMINATE;
1679
1680         return AE_OK;
1681 }
1682
1683 static const struct acpi_device_id ec_device_ids[] = {
1684         {"PNP0C09", 0},
1685         {ACPI_ECDT_HID, 0},
1686         {"", 0},
1687 };
1688
1689 /*
1690  * This function is not Windows-compatible as Windows never enumerates the
1691  * namespace EC before the main ACPI device enumeration process. It is
1692  * retained for historical reason and will be deprecated in the future.
1693  */
1694 void __init acpi_ec_dsdt_probe(void)
1695 {
1696         struct acpi_ec *ec;
1697         acpi_status status;
1698         int ret;
1699
1700         /*
1701          * If a platform has ECDT, there is no need to proceed as the
1702          * following probe is not a part of the ACPI device enumeration,
1703          * executing _STA is not safe, and thus this probe may risk of
1704          * picking up an invalid EC device.
1705          */
1706         if (boot_ec)
1707                 return;
1708
1709         ec = acpi_ec_alloc();
1710         if (!ec)
1711                 return;
1712
1713         /*
1714          * At this point, the namespace is initialized, so start to find
1715          * the namespace objects.
1716          */
1717         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1718         if (ACPI_FAILURE(status) || !ec->handle) {
1719                 acpi_ec_free(ec);
1720                 return;
1721         }
1722
1723         /*
1724          * When the DSDT EC is available, always re-configure boot EC to
1725          * have _REG evaluated. _REG can only be evaluated after the
1726          * namespace initialization.
1727          * At this point, the GPE is not fully initialized, so do not to
1728          * handle the events.
1729          */
1730         ret = acpi_ec_setup(ec, NULL);
1731         if (ret) {
1732                 acpi_ec_free(ec);
1733                 return;
1734         }
1735
1736         boot_ec = ec;
1737
1738         acpi_handle_info(ec->handle,
1739                          "Boot DSDT EC used to handle transactions\n");
1740 }
1741
1742 /*
1743  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1744  *
1745  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1746  * found a matching object in the namespace.
1747  *
1748  * Next, in case the DSDT EC is not functioning, it is still necessary to
1749  * provide a functional ECDT EC to handle events, so add an extra device object
1750  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1751  *
1752  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1753  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1754  */
1755 static void __init acpi_ec_ecdt_start(void)
1756 {
1757         struct acpi_table_ecdt *ecdt_ptr;
1758         acpi_handle handle;
1759         acpi_status status;
1760
1761         /* Bail out if a matching EC has been found in the namespace. */
1762         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1763                 return;
1764
1765         /* Look up the object pointed to from the ECDT in the namespace. */
1766         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1767                                 (struct acpi_table_header **)&ecdt_ptr);
1768         if (ACPI_FAILURE(status))
1769                 return;
1770
1771         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1772         if (ACPI_SUCCESS(status)) {
1773                 boot_ec->handle = handle;
1774
1775                 /* Add a special ACPI device object to represent the boot EC. */
1776                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1777         }
1778
1779         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1780 }
1781
1782 /*
1783  * On some hardware it is necessary to clear events accumulated by the EC during
1784  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1785  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1786  *
1787  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1788  *
1789  * Ideally, the EC should also be instructed NOT to accumulate events during
1790  * sleep (which Windows seems to do somehow), but the interface to control this
1791  * behaviour is not known at this time.
1792  *
1793  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1794  * however it is very likely that other Samsung models are affected.
1795  *
1796  * On systems which don't accumulate _Q events during sleep, this extra check
1797  * should be harmless.
1798  */
1799 static int ec_clear_on_resume(const struct dmi_system_id *id)
1800 {
1801         pr_debug("Detected system needing EC poll on resume.\n");
1802         EC_FLAGS_CLEAR_ON_RESUME = 1;
1803         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1804         return 0;
1805 }
1806
1807 /*
1808  * Some ECDTs contain wrong register addresses.
1809  * MSI MS-171F
1810  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1811  */
1812 static int ec_correct_ecdt(const struct dmi_system_id *id)
1813 {
1814         pr_debug("Detected system needing ECDT address correction.\n");
1815         EC_FLAGS_CORRECT_ECDT = 1;
1816         return 0;
1817 }
1818
1819 /*
1820  * Some DSDTs contain wrong GPE setting.
1821  * Asus FX502VD/VE, GL702VMK, X550VXK, X580VD
1822  * https://bugzilla.kernel.org/show_bug.cgi?id=195651
1823  */
1824 static int ec_honor_ecdt_gpe(const struct dmi_system_id *id)
1825 {
1826         pr_debug("Detected system needing ignore DSDT GPE setting.\n");
1827         EC_FLAGS_IGNORE_DSDT_GPE = 1;
1828         return 0;
1829 }
1830
1831 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1832         {
1833         ec_correct_ecdt, "MSI MS-171F", {
1834         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1835         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),}, NULL},
1836         {
1837         ec_honor_ecdt_gpe, "ASUS FX502VD", {
1838         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1839         DMI_MATCH(DMI_PRODUCT_NAME, "FX502VD"),}, NULL},
1840         {
1841         ec_honor_ecdt_gpe, "ASUS FX502VE", {
1842         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1843         DMI_MATCH(DMI_PRODUCT_NAME, "FX502VE"),}, NULL},
1844         {
1845         ec_honor_ecdt_gpe, "ASUS GL702VMK", {
1846         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1847         DMI_MATCH(DMI_PRODUCT_NAME, "GL702VMK"),}, NULL},
1848         {
1849         ec_honor_ecdt_gpe, "ASUS X550VXK", {
1850         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1851         DMI_MATCH(DMI_PRODUCT_NAME, "X550VXK"),}, NULL},
1852         {
1853         ec_honor_ecdt_gpe, "ASUS X580VD", {
1854         DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
1855         DMI_MATCH(DMI_PRODUCT_NAME, "X580VD"),}, NULL},
1856         {
1857         ec_clear_on_resume, "Samsung hardware", {
1858         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
1859         {},
1860 };
1861
1862 void __init acpi_ec_ecdt_probe(void)
1863 {
1864         struct acpi_table_ecdt *ecdt_ptr;
1865         struct acpi_ec *ec;
1866         acpi_status status;
1867         int ret;
1868
1869         /* Generate a boot ec context. */
1870         dmi_check_system(ec_dmi_table);
1871         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1872                                 (struct acpi_table_header **)&ecdt_ptr);
1873         if (ACPI_FAILURE(status))
1874                 return;
1875
1876         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1877                 /*
1878                  * Asus X50GL:
1879                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1880                  */
1881                 goto out;
1882         }
1883
1884         ec = acpi_ec_alloc();
1885         if (!ec)
1886                 goto out;
1887
1888         if (EC_FLAGS_CORRECT_ECDT) {
1889                 ec->command_addr = ecdt_ptr->data.address;
1890                 ec->data_addr = ecdt_ptr->control.address;
1891         } else {
1892                 ec->command_addr = ecdt_ptr->control.address;
1893                 ec->data_addr = ecdt_ptr->data.address;
1894         }
1895
1896         /*
1897          * Ignore the GPE value on Reduced Hardware platforms.
1898          * Some products have this set to an erroneous value.
1899          */
1900         if (!acpi_gbl_reduced_hardware)
1901                 ec->gpe = ecdt_ptr->gpe;
1902
1903         ec->handle = ACPI_ROOT_OBJECT;
1904
1905         /*
1906          * At this point, the namespace is not initialized, so do not find
1907          * the namespace objects, or handle the events.
1908          */
1909         ret = acpi_ec_setup(ec, NULL);
1910         if (ret) {
1911                 acpi_ec_free(ec);
1912                 goto out;
1913         }
1914
1915         boot_ec = ec;
1916         boot_ec_is_ecdt = true;
1917
1918         pr_info("Boot ECDT EC used to handle transactions\n");
1919
1920 out:
1921         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1922 }
1923
1924 #ifdef CONFIG_PM_SLEEP
1925 static int acpi_ec_suspend(struct device *dev)
1926 {
1927         struct acpi_ec *ec =
1928                 acpi_driver_data(to_acpi_device(dev));
1929
1930         if (!pm_suspend_no_platform() && ec_freeze_events)
1931                 acpi_ec_disable_event(ec);
1932         return 0;
1933 }
1934
1935 static int acpi_ec_suspend_noirq(struct device *dev)
1936 {
1937         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1938
1939         /*
1940          * The SCI handler doesn't run at this point, so the GPE can be
1941          * masked at the low level without side effects.
1942          */
1943         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1944             ec->gpe >= 0 && ec->reference_count >= 1)
1945                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1946
1947         acpi_ec_enter_noirq(ec);
1948
1949         return 0;
1950 }
1951
1952 static int acpi_ec_resume_noirq(struct device *dev)
1953 {
1954         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1955
1956         acpi_ec_leave_noirq(ec);
1957
1958         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1959             ec->gpe >= 0 && ec->reference_count >= 1)
1960                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
1961
1962         return 0;
1963 }
1964
1965 static int acpi_ec_resume(struct device *dev)
1966 {
1967         struct acpi_ec *ec =
1968                 acpi_driver_data(to_acpi_device(dev));
1969
1970         acpi_ec_enable_event(ec);
1971         return 0;
1972 }
1973
1974 void acpi_ec_mark_gpe_for_wake(void)
1975 {
1976         if (first_ec && !ec_no_wakeup)
1977                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
1978 }
1979 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
1980
1981 void acpi_ec_set_gpe_wake_mask(u8 action)
1982 {
1983         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
1984                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
1985 }
1986
1987 bool acpi_ec_dispatch_gpe(void)
1988 {
1989         u32 ret;
1990
1991         if (!first_ec)
1992                 return acpi_any_gpe_status_set(U32_MAX);
1993
1994         /*
1995          * Report wakeup if the status bit is set for any enabled GPE other
1996          * than the EC one.
1997          */
1998         if (acpi_any_gpe_status_set(first_ec->gpe))
1999                 return true;
2000
2001         /*
2002          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2003          * to allow the caller to process events properly after that.
2004          */
2005         ret = acpi_dispatch_gpe(NULL, first_ec->gpe);
2006         if (ret == ACPI_INTERRUPT_HANDLED)
2007                 pm_pr_dbg("ACPI EC GPE dispatched\n");
2008
2009         /* Flush the event and query workqueues. */
2010         acpi_ec_flush_work();
2011
2012         return false;
2013 }
2014 #endif /* CONFIG_PM_SLEEP */
2015
2016 static const struct dev_pm_ops acpi_ec_pm = {
2017         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2018         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2019 };
2020
2021 static int param_set_event_clearing(const char *val,
2022                                     const struct kernel_param *kp)
2023 {
2024         int result = 0;
2025
2026         if (!strncmp(val, "status", sizeof("status") - 1)) {
2027                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2028                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2029         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2030                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2031                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2032         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2033                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2034                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2035         } else
2036                 result = -EINVAL;
2037         return result;
2038 }
2039
2040 static int param_get_event_clearing(char *buffer,
2041                                     const struct kernel_param *kp)
2042 {
2043         switch (ec_event_clearing) {
2044         case ACPI_EC_EVT_TIMING_STATUS:
2045                 return sprintf(buffer, "status\n");
2046         case ACPI_EC_EVT_TIMING_QUERY:
2047                 return sprintf(buffer, "query\n");
2048         case ACPI_EC_EVT_TIMING_EVENT:
2049                 return sprintf(buffer, "event\n");
2050         default:
2051                 return sprintf(buffer, "invalid\n");
2052         }
2053         return 0;
2054 }
2055
2056 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2057                   NULL, 0644);
2058 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2059
2060 static struct acpi_driver acpi_ec_driver = {
2061         .name = "ec",
2062         .class = ACPI_EC_CLASS,
2063         .ids = ec_device_ids,
2064         .ops = {
2065                 .add = acpi_ec_add,
2066                 .remove = acpi_ec_remove,
2067                 },
2068         .drv.pm = &acpi_ec_pm,
2069 };
2070
2071 static void acpi_ec_destroy_workqueues(void)
2072 {
2073         if (ec_wq) {
2074                 destroy_workqueue(ec_wq);
2075                 ec_wq = NULL;
2076         }
2077         if (ec_query_wq) {
2078                 destroy_workqueue(ec_query_wq);
2079                 ec_query_wq = NULL;
2080         }
2081 }
2082
2083 static int acpi_ec_init_workqueues(void)
2084 {
2085         if (!ec_wq)
2086                 ec_wq = alloc_ordered_workqueue("kec", 0);
2087
2088         if (!ec_query_wq)
2089                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2090
2091         if (!ec_wq || !ec_query_wq) {
2092                 acpi_ec_destroy_workqueues();
2093                 return -ENODEV;
2094         }
2095         return 0;
2096 }
2097
2098 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2099         {
2100                 .ident = "Thinkpad X1 Carbon 6th",
2101                 .matches = {
2102                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2103                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2104                 },
2105         },
2106         {
2107                 .ident = "ThinkPad X1 Carbon 6th",
2108                 .matches = {
2109                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2110                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Carbon 6th"),
2111                 },
2112         },
2113         {
2114                 .ident = "ThinkPad X1 Yoga 3rd",
2115                 .matches = {
2116                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2117                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2118                 },
2119         },
2120         { },
2121 };
2122
2123 void __init acpi_ec_init(void)
2124 {
2125         int result;
2126
2127         result = acpi_ec_init_workqueues();
2128         if (result)
2129                 return;
2130
2131         /*
2132          * Disable EC wakeup on following systems to prevent periodic
2133          * wakeup from EC GPE.
2134          */
2135         if (dmi_check_system(acpi_ec_no_wakeup)) {
2136                 ec_no_wakeup = true;
2137                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2138         }
2139
2140         /* Driver must be registered after acpi_ec_init_workqueues(). */
2141         acpi_bus_register_driver(&acpi_ec_driver);
2142
2143         acpi_ec_ecdt_start();
2144 }
2145
2146 /* EC driver currently not unloadable */
2147 #if 0
2148 static void __exit acpi_ec_exit(void)
2149 {
2150
2151         acpi_bus_unregister_driver(&acpi_ec_driver);
2152         acpi_ec_destroy_workqueues();
2153 }
2154 #endif  /* 0 */