drivers/acpi/ec.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ec.c - ACPI Embedded Controller Driver (v3)
   4  *
   5  *  Copyright (C) 2001-2015 Intel Corporation
   6  *    Author: 2014, 2015 Lv Zheng <[email protected]>
   7  *            2006, 2007 Alexey Starikovskiy <[email protected]>
   8  *            2006       Denis Sadykov <[email protected]>
   9  *            2004       Luming Yu <[email protected]>
  10  *            2001, 2002 Andy Grover <[email protected]>
  11  *            2001, 2002 Paul Diefenbaugh <[email protected]>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <[email protected]>
  13  */
  14
  15 /* Uncomment next line to get verbose printout */
  16 /* #define DEBUG */
  17 #define pr_fmt(fmt) "ACPI: EC: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/types.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/list.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/slab.h>
  28 #include <linux/suspend.h>
  29 #include <linux/acpi.h>
  30 #include <linux/dmi.h>
  31 #include <asm/io.h>
  32
  33 #include "internal.h"
  34
  35 #define ACPI_EC_CLASS                   "embedded_controller"
  36 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  37
  38 /* EC status register */
  39 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  40 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  41 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  42 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  43 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  44
  45 /*
  46  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  47  * This leads to lots of practical timing issues for the host EC driver.
  48  * The following variations are defined (from the target EC firmware's
  49  * perspective):
  50  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  51  *         target can clear SCI_EVT at any time so long as the host can see
  52  *         the indication by reading the status register (EC_SC). So the
  53  *         host should re-check SCI_EVT after the first time the SCI_EVT
  54  *         indication is seen, which is the same time the query request
  55  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  56  *         at any later time could indicate another event. Normally such
  57  *         kind of EC firmware has implemented an event queue and will
  58  *         return 0x00 to indicate "no outstanding event".
  59  * QUERY: After seeing the query request (QR_EC) written to the command
  60  *        register (EC_CMD) by the host and having prepared the responding
  61  *        event value in the data register (EC_DATA), the target can safely
  62  *        clear SCI_EVT because the target can confirm that the current
  63  *        event is being handled by the host. The host then should check
  64  *        SCI_EVT right after reading the event response from the data
  65  *        register (EC_DATA).
  66  * EVENT: After seeing the event response read from the data register
  67  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  68  *        target requires time to notice the change in the data register
  69  *        (EC_DATA), the host may be required to wait additional guarding
  70  *        time before checking the SCI_EVT again. Such guarding may not be
  71  *        necessary if the host is notified via another IRQ.
  72  */
  73 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  74 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  75 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  76
  77 /* EC commands */
  78 enum ec_command {
  79         ACPI_EC_COMMAND_READ = 0x80,
  80         ACPI_EC_COMMAND_WRITE = 0x81,
  81         ACPI_EC_BURST_ENABLE = 0x82,
  82         ACPI_EC_BURST_DISABLE = 0x83,
  83         ACPI_EC_COMMAND_QUERY = 0x84,
  84 };
  85
  86 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  87 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  88 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
  89 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  90                                          * when trying to clear the EC */
  91 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
  92
  93 enum {
  94         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
  95         EC_FLAGS_EVENT_HANDLER_INSTALLED,       /* Event handler installed */
  96         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
  97         EC_FLAGS_EC_REG_CALLED,         /* OpReg ACPI _REG method called */
  98         EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
  99         EC_FLAGS_STARTED,               /* Driver is started */
 100         EC_FLAGS_STOPPED,               /* Driver is stopped */
 101         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 102 };
 103
 104 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 105 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 106
 107 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 108 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 109 module_param(ec_delay, uint, 0644);
 110 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 111
 112 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 113 module_param(ec_max_queries, uint, 0644);
 114 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 115
 116 static bool ec_busy_polling __read_mostly;
 117 module_param(ec_busy_polling, bool, 0644);
 118 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 119
 120 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 121 module_param(ec_polling_guard, uint, 0644);
 122 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 123
 124 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 125
 126 /*
 127  * If the number of false interrupts per one transaction exceeds
 128  * this threshold, will think there is a GPE storm happened and
 129  * will disable the GPE for normal transaction.
 130  */
 131 static unsigned int ec_storm_threshold  __read_mostly = 8;
 132 module_param(ec_storm_threshold, uint, 0644);
 133 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 134
 135 static bool ec_freeze_events __read_mostly;
 136 module_param(ec_freeze_events, bool, 0644);
 137 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 138
 139 static bool ec_no_wakeup __read_mostly;
 140 module_param(ec_no_wakeup, bool, 0644);
 141 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 142
 143 struct acpi_ec_query_handler {
 144         struct list_head node;
 145         acpi_ec_query_func func;
 146         acpi_handle handle;
 147         void *data;
 148         u8 query_bit;
 149         struct kref kref;
 150 };
 151
 152 struct transaction {
 153         const u8 *wdata;
 154         u8 *rdata;
 155         unsigned short irq_count;
 156         u8 command;
 157         u8 wi;
 158         u8 ri;
 159         u8 wlen;
 160         u8 rlen;
 161         u8 flags;
 162 };
 163
 164 struct acpi_ec_query {
 165         struct transaction transaction;
 166         struct work_struct work;
 167         struct acpi_ec_query_handler *handler;
 168         struct acpi_ec *ec;
 169 };
 170
 171 static int acpi_ec_submit_query(struct acpi_ec *ec);
 172 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 173 static void acpi_ec_event_handler(struct work_struct *work);
 174
 175 struct acpi_ec *first_ec;
 176 EXPORT_SYMBOL(first_ec);
 177
 178 static struct acpi_ec *boot_ec;
 179 static bool boot_ec_is_ecdt;
 180 static struct workqueue_struct *ec_wq;
 181 static struct workqueue_struct *ec_query_wq;
 182
 183 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 184 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 185 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 186
 187 /* --------------------------------------------------------------------------
 188  *                           Logging/Debugging
 189  * -------------------------------------------------------------------------- */
 190
 191 /*
 192  * Splitters used by the developers to track the boundary of the EC
 193  * handling processes.
 194  */
 195 #ifdef DEBUG
 196 #define EC_DBG_SEP      " "
 197 #define EC_DBG_DRV      "+++++"
 198 #define EC_DBG_STM      "====="
 199 #define EC_DBG_REQ      "*****"
 200 #define EC_DBG_EVT      "#####"
 201 #else
 202 #define EC_DBG_SEP      ""
 203 #define EC_DBG_DRV
 204 #define EC_DBG_STM
 205 #define EC_DBG_REQ
 206 #define EC_DBG_EVT
 207 #endif
 208
 209 #define ec_log_raw(fmt, ...) \
 210         pr_info(fmt "\n", ##__VA_ARGS__)
 211 #define ec_dbg_raw(fmt, ...) \
 212         pr_debug(fmt "\n", ##__VA_ARGS__)
 213 #define ec_log(filter, fmt, ...) \
 214         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 215 #define ec_dbg(filter, fmt, ...) \
 216         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 217
 218 #define ec_log_drv(fmt, ...) \
 219         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 220 #define ec_dbg_drv(fmt, ...) \
 221         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 222 #define ec_dbg_stm(fmt, ...) \
 223         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 224 #define ec_dbg_req(fmt, ...) \
 225         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 226 #define ec_dbg_evt(fmt, ...) \
 227         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 228 #define ec_dbg_ref(ec, fmt, ...) \
 229         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 230
 231 /* --------------------------------------------------------------------------
 232  *                           Device Flags
 233  * -------------------------------------------------------------------------- */
 234
 235 static bool acpi_ec_started(struct acpi_ec *ec)
 236 {
 237         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 238                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 239 }
 240
 241 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 242 {
 243         /*
 244          * There is an OSPM early stage logic. During the early stages
 245          * (boot/resume), OSPMs shouldn't enable the event handling, only
 246          * the EC transactions are allowed to be performed.
 247          */
 248         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 249                 return false;
 250         /*
 251          * However, disabling the event handling is experimental for late
 252          * stage (suspend), and is controlled by the boot parameter of
 253          * "ec_freeze_events":
 254          * 1. true:  The EC event handling is disabled before entering
 255          *           the noirq stage.
 256          * 2. false: The EC event handling is automatically disabled as
 257          *           soon as the EC driver is stopped.
 258          */
 259         if (ec_freeze_events)
 260                 return acpi_ec_started(ec);
 261         else
 262                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 263 }
 264
 265 static bool acpi_ec_flushed(struct acpi_ec *ec)
 266 {
 267         return ec->reference_count == 1;
 268 }
 269
 270 /* --------------------------------------------------------------------------
 271  *                           EC Registers
 272  * -------------------------------------------------------------------------- */
 273
 274 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 275 {
 276         u8 x = inb(ec->command_addr);
 277
 278         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 279                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 280                    x,
 281                    !!(x & ACPI_EC_FLAG_SCI),
 282                    !!(x & ACPI_EC_FLAG_BURST),
 283                    !!(x & ACPI_EC_FLAG_CMD),
 284                    !!(x & ACPI_EC_FLAG_IBF),
 285                    !!(x & ACPI_EC_FLAG_OBF));
 286         return x;
 287 }
 288
 289 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 290 {
 291         u8 x = inb(ec->data_addr);
 292
 293         ec->timestamp = jiffies;
 294         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 295         return x;
 296 }
 297
 298 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 299 {
 300         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 301         outb(command, ec->command_addr);
 302         ec->timestamp = jiffies;
 303 }
 304
 305 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 306 {
 307         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 308         outb(data, ec->data_addr);
 309         ec->timestamp = jiffies;
 310 }
 311
 312 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 313 static const char *acpi_ec_cmd_string(u8 cmd)
 314 {
 315         switch (cmd) {
 316         case 0x80:
 317                 return "RD_EC";
 318         case 0x81:
 319                 return "WR_EC";
 320         case 0x82:
 321                 return "BE_EC";
 322         case 0x83:
 323                 return "BD_EC";
 324         case 0x84:
 325                 return "QR_EC";
 326         }
 327         return "UNKNOWN";
 328 }
 329 #else
 330 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 331 #endif
 332
 333 /* --------------------------------------------------------------------------
 334  *                           GPE Registers
 335  * -------------------------------------------------------------------------- */
 336
 337 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 338 {
 339         acpi_event_status gpe_status = 0;
 340
 341         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 342         return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 343 }
 344
 345 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 346 {
 347         if (open)
 348                 acpi_enable_gpe(NULL, ec->gpe);
 349         else {
 350                 BUG_ON(ec->reference_count < 1);
 351                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 352         }
 353         if (acpi_ec_gpe_status_set(ec)) {
 354                 /*
 355                  * On some platforms, EN=1 writes cannot trigger GPE. So
 356                  * software need to manually trigger a pseudo GPE event on
 357                  * EN=1 writes.
 358                  */
 359                 ec_dbg_raw("Polling quirk");
 360                 advance_transaction(ec, false);
 361         }
 362 }
 363
 364 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 365 {
 366         if (close)
 367                 acpi_disable_gpe(NULL, ec->gpe);
 368         else {
 369                 BUG_ON(ec->reference_count < 1);
 370                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 371         }
 372 }
 373
 374 /* --------------------------------------------------------------------------
 375  *                           Transaction Management
 376  * -------------------------------------------------------------------------- */
 377
 378 static void acpi_ec_submit_request(struct acpi_ec *ec)
 379 {
 380         ec->reference_count++;
 381         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 382             ec->gpe >= 0 && ec->reference_count == 1)
 383                 acpi_ec_enable_gpe(ec, true);
 384 }
 385
 386 static void acpi_ec_complete_request(struct acpi_ec *ec)
 387 {
 388         bool flushed = false;
 389
 390         ec->reference_count--;
 391         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 392             ec->gpe >= 0 && ec->reference_count == 0)
 393                 acpi_ec_disable_gpe(ec, true);
 394         flushed = acpi_ec_flushed(ec);
 395         if (flushed)
 396                 wake_up(&ec->wait);
 397 }
 398
 399 static void acpi_ec_mask_events(struct acpi_ec *ec)
 400 {
 401         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 402                 if (ec->gpe >= 0)
 403                         acpi_ec_disable_gpe(ec, false);
 404                 else
 405                         disable_irq_nosync(ec->irq);
 406
 407                 ec_dbg_drv("Polling enabled");
 408                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 409         }
 410 }
 411
 412 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 413 {
 414         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 415                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 416                 if (ec->gpe >= 0)
 417                         acpi_ec_enable_gpe(ec, false);
 418                 else
 419                         enable_irq(ec->irq);
 420
 421                 ec_dbg_drv("Polling disabled");
 422         }
 423 }
 424
 425 /*
 426  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 427  *                                      the flush operation is not in
 428  *                                      progress
 429  * @ec: the EC device
 430  *
 431  * This function must be used before taking a new action that should hold
 432  * the reference count.  If this function returns false, then the action
 433  * must be discarded or it will prevent the flush operation from being
 434  * completed.
 435  */
 436 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 437 {
 438         if (!acpi_ec_started(ec))
 439                 return false;
 440         acpi_ec_submit_request(ec);
 441         return true;
 442 }
 443
 444 static void acpi_ec_submit_event(struct acpi_ec *ec)
 445 {
 446         /*
 447          * It is safe to mask the events here, because acpi_ec_close_event()
 448          * will run at least once after this.
 449          */
 450         acpi_ec_mask_events(ec);
 451         if (!acpi_ec_event_enabled(ec))
 452                 return;
 453
 454         if (ec->event_state != EC_EVENT_READY)
 455                 return;
 456
 457         ec_dbg_evt("Command(%s) submitted/blocked",
 458                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 459
 460         ec->event_state = EC_EVENT_IN_PROGRESS;
 461         /*
 462          * If events_to_process is greater than 0 at this point, the while ()
 463          * loop in acpi_ec_event_handler() is still running and incrementing
 464          * events_to_process will cause it to invoke acpi_ec_submit_query() once
 465          * more, so it is not necessary to queue up the event work to start the
 466          * same loop again.
 467          */
 468         if (ec->events_to_process++ > 0)
 469                 return;
 470
 471         ec->events_in_progress++;
 472         queue_work(ec_wq, &ec->work);
 473 }
 474
 475 static void acpi_ec_complete_event(struct acpi_ec *ec)
 476 {
 477         if (ec->event_state == EC_EVENT_IN_PROGRESS)
 478                 ec->event_state = EC_EVENT_COMPLETE;
 479 }
 480
 481 static void acpi_ec_close_event(struct acpi_ec *ec)
 482 {
 483         if (ec->event_state != EC_EVENT_READY)
 484                 ec_dbg_evt("Command(%s) unblocked",
 485                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 486
 487         ec->event_state = EC_EVENT_READY;
 488         acpi_ec_unmask_events(ec);
 489 }
 490
 491 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 492 {
 493         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 494                 ec_log_drv("event unblocked");
 495         /*
 496          * Unconditionally invoke this once after enabling the event
 497          * handling mechanism to detect the pending events.
 498          */
 499         advance_transaction(ec, false);
 500 }
 501
 502 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 503 {
 504         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 505                 ec_log_drv("event blocked");
 506 }
 507
 508 /*
 509  * Process _Q events that might have accumulated in the EC.
 510  * Run with locked ec mutex.
 511  */
 512 static void acpi_ec_clear(struct acpi_ec *ec)
 513 {
 514         int i;
 515
 516         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 517                 if (acpi_ec_submit_query(ec))
 518                         break;
 519         }
 520         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 521                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 522         else
 523                 pr_info("%d stale EC events cleared\n", i);
 524 }
 525
 526 static void acpi_ec_enable_event(struct acpi_ec *ec)
 527 {
 528         unsigned long flags;
 529
 530         spin_lock_irqsave(&ec->lock, flags);
 531         if (acpi_ec_started(ec))
 532                 __acpi_ec_enable_event(ec);
 533         spin_unlock_irqrestore(&ec->lock, flags);
 534
 535         /* Drain additional events if hardware requires that */
 536         if (EC_FLAGS_CLEAR_ON_RESUME)
 537                 acpi_ec_clear(ec);
 538 }
 539
 540 #ifdef CONFIG_PM_SLEEP
 541 static void __acpi_ec_flush_work(void)
 542 {
 543         flush_workqueue(ec_wq); /* flush ec->work */
 544         flush_workqueue(ec_query_wq); /* flush queries */
 545 }
 546
 547 static void acpi_ec_disable_event(struct acpi_ec *ec)
 548 {
 549         unsigned long flags;
 550
 551         spin_lock_irqsave(&ec->lock, flags);
 552         __acpi_ec_disable_event(ec);
 553         spin_unlock_irqrestore(&ec->lock, flags);
 554
 555         /*
 556          * When ec_freeze_events is true, we need to flush events in
 557          * the proper position before entering the noirq stage.
 558          */
 559         __acpi_ec_flush_work();
 560 }
 561
 562 void acpi_ec_flush_work(void)
 563 {
 564         /* Without ec_wq there is nothing to flush. */
 565         if (!ec_wq)
 566                 return;
 567
 568         __acpi_ec_flush_work();
 569 }
 570 #endif /* CONFIG_PM_SLEEP */
 571
 572 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 573 {
 574         unsigned long flags;
 575         bool guarded;
 576
 577         spin_lock_irqsave(&ec->lock, flags);
 578         /*
 579          * If firmware SCI_EVT clearing timing is "event", we actually
 580          * don't know when the SCI_EVT will be cleared by firmware after
 581          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 582          * acceptable period.
 583          *
 584          * The guarding period is applicable if the event state is not
 585          * EC_EVENT_READY, but otherwise if the current transaction is of the
 586          * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
 587          * and it should not be applied to let the transaction transition into
 588          * the ACPI_EC_COMMAND_POLL state immediately.
 589          */
 590         guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 591                 ec->event_state != EC_EVENT_READY &&
 592                 (!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
 593         spin_unlock_irqrestore(&ec->lock, flags);
 594         return guarded;
 595 }
 596
 597 static int ec_transaction_polled(struct acpi_ec *ec)
 598 {
 599         unsigned long flags;
 600         int ret = 0;
 601
 602         spin_lock_irqsave(&ec->lock, flags);
 603         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 604                 ret = 1;
 605         spin_unlock_irqrestore(&ec->lock, flags);
 606         return ret;
 607 }
 608
 609 static int ec_transaction_completed(struct acpi_ec *ec)
 610 {
 611         unsigned long flags;
 612         int ret = 0;
 613
 614         spin_lock_irqsave(&ec->lock, flags);
 615         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 616                 ret = 1;
 617         spin_unlock_irqrestore(&ec->lock, flags);
 618         return ret;
 619 }
 620
 621 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 622 {
 623         ec->curr->flags |= flag;
 624
 625         if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
 626                 return;
 627
 628         switch (ec_event_clearing) {
 629         case ACPI_EC_EVT_TIMING_STATUS:
 630                 if (flag == ACPI_EC_COMMAND_POLL)
 631                         acpi_ec_close_event(ec);
 632
 633                 return;
 634
 635         case ACPI_EC_EVT_TIMING_QUERY:
 636                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 637                         acpi_ec_close_event(ec);
 638
 639                 return;
 640
 641         case ACPI_EC_EVT_TIMING_EVENT:
 642                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 643                         acpi_ec_complete_event(ec);
 644         }
 645 }
 646
 647 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 648 {
 649         if (t->irq_count < ec_storm_threshold)
 650                 ++t->irq_count;
 651
 652         /* Trigger if the threshold is 0 too. */
 653         if (t->irq_count == ec_storm_threshold)
 654                 acpi_ec_mask_events(ec);
 655 }
 656
 657 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 658 {
 659         struct transaction *t = ec->curr;
 660         bool wakeup = false;
 661         u8 status;
 662
 663         ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 664
 665         status = acpi_ec_read_status(ec);
 666
 667         /*
 668          * Another IRQ or a guarded polling mode advancement is detected,
 669          * the next QR_EC submission is then allowed.
 670          */
 671         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 672                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 673                     ec->event_state == EC_EVENT_COMPLETE)
 674                         acpi_ec_close_event(ec);
 675
 676                 if (!t)
 677                         goto out;
 678         }
 679
 680         if (t->flags & ACPI_EC_COMMAND_POLL) {
 681                 if (t->wlen > t->wi) {
 682                         if (!(status & ACPI_EC_FLAG_IBF))
 683                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 684                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 685                                 acpi_ec_spurious_interrupt(ec, t);
 686                 } else if (t->rlen > t->ri) {
 687                         if (status & ACPI_EC_FLAG_OBF) {
 688                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 689                                 if (t->rlen == t->ri) {
 690                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 691                                         wakeup = true;
 692                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 693                                                 ec_dbg_evt("Command(%s) completed by hardware",
 694                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 695                                 }
 696                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 697                                 acpi_ec_spurious_interrupt(ec, t);
 698                         }
 699                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 700                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 701                         wakeup = true;
 702                 }
 703         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 704                 acpi_ec_write_cmd(ec, t->command);
 705                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 706         }
 707
 708 out:
 709         if (status & ACPI_EC_FLAG_SCI)
 710                 acpi_ec_submit_event(ec);
 711
 712         if (wakeup && interrupt)
 713                 wake_up(&ec->wait);
 714 }
 715
 716 static void start_transaction(struct acpi_ec *ec)
 717 {
 718         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 719         ec->curr->flags = 0;
 720 }
 721
 722 static int ec_guard(struct acpi_ec *ec)
 723 {
 724         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 725         unsigned long timeout = ec->timestamp + guard;
 726
 727         /* Ensure guarding period before polling EC status */
 728         do {
 729                 if (ec->busy_polling) {
 730                         /* Perform busy polling */
 731                         if (ec_transaction_completed(ec))
 732                                 return 0;
 733                         udelay(jiffies_to_usecs(guard));
 734                 } else {
 735                         /*
 736                          * Perform wait polling
 737                          * 1. Wait the transaction to be completed by the
 738                          *    GPE handler after the transaction enters
 739                          *    ACPI_EC_COMMAND_POLL state.
 740                          * 2. A special guarding logic is also required
 741                          *    for event clearing mode "event" before the
 742                          *    transaction enters ACPI_EC_COMMAND_POLL
 743                          *    state.
 744                          */
 745                         if (!ec_transaction_polled(ec) &&
 746                             !acpi_ec_guard_event(ec))
 747                                 break;
 748                         if (wait_event_timeout(ec->wait,
 749                                                ec_transaction_completed(ec),
 750                                                guard))
 751                                 return 0;
 752                 }
 753         } while (time_before(jiffies, timeout));
 754         return -ETIME;
 755 }
 756
 757 static int ec_poll(struct acpi_ec *ec)
 758 {
 759         unsigned long flags;
 760         int repeat = 5; /* number of command restarts */
 761
 762         while (repeat--) {
 763                 unsigned long delay = jiffies +
 764                         msecs_to_jiffies(ec_delay);
 765                 do {
 766                         if (!ec_guard(ec))
 767                                 return 0;
 768                         spin_lock_irqsave(&ec->lock, flags);
 769                         advance_transaction(ec, false);
 770                         spin_unlock_irqrestore(&ec->lock, flags);
 771                 } while (time_before(jiffies, delay));
 772                 pr_debug("controller reset, restart transaction\n");
 773                 spin_lock_irqsave(&ec->lock, flags);
 774                 start_transaction(ec);
 775                 spin_unlock_irqrestore(&ec->lock, flags);
 776         }
 777         return -ETIME;
 778 }
 779
 780 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 781                                         struct transaction *t)
 782 {
 783         unsigned long tmp;
 784         int ret = 0;
 785
 786         /* start transaction */
 787         spin_lock_irqsave(&ec->lock, tmp);
 788         /* Enable GPE for command processing (IBF=0/OBF=1) */
 789         if (!acpi_ec_submit_flushable_request(ec)) {
 790                 ret = -EINVAL;
 791                 goto unlock;
 792         }
 793         ec_dbg_ref(ec, "Increase command");
 794         /* following two actions should be kept atomic */
 795         ec->curr = t;
 796         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 797         start_transaction(ec);
 798         spin_unlock_irqrestore(&ec->lock, tmp);
 799
 800         ret = ec_poll(ec);
 801
 802         spin_lock_irqsave(&ec->lock, tmp);
 803         if (t->irq_count == ec_storm_threshold)
 804                 acpi_ec_unmask_events(ec);
 805         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 806         ec->curr = NULL;
 807         /* Disable GPE for command processing (IBF=0/OBF=1) */
 808         acpi_ec_complete_request(ec);
 809         ec_dbg_ref(ec, "Decrease command");
 810 unlock:
 811         spin_unlock_irqrestore(&ec->lock, tmp);
 812         return ret;
 813 }
 814
 815 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 816 {
 817         int status;
 818         u32 glk;
 819
 820         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 821                 return -EINVAL;
 822         if (t->rdata)
 823                 memset(t->rdata, 0, t->rlen);
 824
 825         mutex_lock(&ec->mutex);
 826         if (ec->global_lock) {
 827                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 828                 if (ACPI_FAILURE(status)) {
 829                         status = -ENODEV;
 830                         goto unlock;
 831                 }
 832         }
 833
 834         status = acpi_ec_transaction_unlocked(ec, t);
 835
 836         if (ec->global_lock)
 837                 acpi_release_global_lock(glk);
 838 unlock:
 839         mutex_unlock(&ec->mutex);
 840         return status;
 841 }
 842
 843 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 844 {
 845         u8 d;
 846         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 847                                 .wdata = NULL, .rdata = &d,
 848                                 .wlen = 0, .rlen = 1};
 849
 850         return acpi_ec_transaction(ec, &t);
 851 }
 852
 853 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 854 {
 855         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 856                                 .wdata = NULL, .rdata = NULL,
 857                                 .wlen = 0, .rlen = 0};
 858
 859         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 860                                 acpi_ec_transaction(ec, &t) : 0;
 861 }
 862
 863 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 864 {
 865         int result;
 866         u8 d;
 867         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 868                                 .wdata = &address, .rdata = &d,
 869                                 .wlen = 1, .rlen = 1};
 870
 871         result = acpi_ec_transaction(ec, &t);
 872         *data = d;
 873         return result;
 874 }
 875
 876 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 877 {
 878         u8 wdata[2] = { address, data };
 879         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 880                                 .wdata = wdata, .rdata = NULL,
 881                                 .wlen = 2, .rlen = 0};
 882
 883         return acpi_ec_transaction(ec, &t);
 884 }
 885
 886 int ec_read(u8 addr, u8 *val)
 887 {
 888         int err;
 889         u8 temp_data;
 890
 891         if (!first_ec)
 892                 return -ENODEV;
 893
 894         err = acpi_ec_read(first_ec, addr, &temp_data);
 895
 896         if (!err) {
 897                 *val = temp_data;
 898                 return 0;
 899         }
 900         return err;
 901 }
 902 EXPORT_SYMBOL(ec_read);
 903
 904 int ec_write(u8 addr, u8 val)
 905 {
 906         if (!first_ec)
 907                 return -ENODEV;
 908
 909         return acpi_ec_write(first_ec, addr, val);
 910 }
 911 EXPORT_SYMBOL(ec_write);
 912
 913 int ec_transaction(u8 command,
 914                    const u8 *wdata, unsigned wdata_len,
 915                    u8 *rdata, unsigned rdata_len)
 916 {
 917         struct transaction t = {.command = command,
 918                                 .wdata = wdata, .rdata = rdata,
 919                                 .wlen = wdata_len, .rlen = rdata_len};
 920
 921         if (!first_ec)
 922                 return -ENODEV;
 923
 924         return acpi_ec_transaction(first_ec, &t);
 925 }
 926 EXPORT_SYMBOL(ec_transaction);
 927
 928 /* Get the handle to the EC device */
 929 acpi_handle ec_get_handle(void)
 930 {
 931         if (!first_ec)
 932                 return NULL;
 933         return first_ec->handle;
 934 }
 935 EXPORT_SYMBOL(ec_get_handle);
 936
 937 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 938 {
 939         unsigned long flags;
 940
 941         spin_lock_irqsave(&ec->lock, flags);
 942         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 943                 ec_dbg_drv("Starting EC");
 944                 /* Enable GPE for event processing (SCI_EVT=1) */
 945                 if (!resuming) {
 946                         acpi_ec_submit_request(ec);
 947                         ec_dbg_ref(ec, "Increase driver");
 948                 }
 949                 ec_log_drv("EC started");
 950         }
 951         spin_unlock_irqrestore(&ec->lock, flags);
 952 }
 953
 954 static bool acpi_ec_stopped(struct acpi_ec *ec)
 955 {
 956         unsigned long flags;
 957         bool flushed;
 958
 959         spin_lock_irqsave(&ec->lock, flags);
 960         flushed = acpi_ec_flushed(ec);
 961         spin_unlock_irqrestore(&ec->lock, flags);
 962         return flushed;
 963 }
 964
 965 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 966 {
 967         unsigned long flags;
 968
 969         spin_lock_irqsave(&ec->lock, flags);
 970         if (acpi_ec_started(ec)) {
 971                 ec_dbg_drv("Stopping EC");
 972                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 973                 spin_unlock_irqrestore(&ec->lock, flags);
 974                 wait_event(ec->wait, acpi_ec_stopped(ec));
 975                 spin_lock_irqsave(&ec->lock, flags);
 976                 /* Disable GPE for event processing (SCI_EVT=1) */
 977                 if (!suspending) {
 978                         acpi_ec_complete_request(ec);
 979                         ec_dbg_ref(ec, "Decrease driver");
 980                 } else if (!ec_freeze_events)
 981                         __acpi_ec_disable_event(ec);
 982                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 983                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 984                 ec_log_drv("EC stopped");
 985         }
 986         spin_unlock_irqrestore(&ec->lock, flags);
 987 }
 988
 989 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
 990 {
 991         unsigned long flags;
 992
 993         spin_lock_irqsave(&ec->lock, flags);
 994         ec->busy_polling = true;
 995         ec->polling_guard = 0;
 996         ec_log_drv("interrupt blocked");
 997         spin_unlock_irqrestore(&ec->lock, flags);
 998 }
 999
1000 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1001 {
1002         unsigned long flags;
1003
1004         spin_lock_irqsave(&ec->lock, flags);
1005         ec->busy_polling = ec_busy_polling;
1006         ec->polling_guard = ec_polling_guard;
1007         ec_log_drv("interrupt unblocked");
1008         spin_unlock_irqrestore(&ec->lock, flags);
1009 }
1010
1011 void acpi_ec_block_transactions(void)
1012 {
1013         struct acpi_ec *ec = first_ec;
1014
1015         if (!ec)
1016                 return;
1017
1018         mutex_lock(&ec->mutex);
1019         /* Prevent transactions from being carried out */
1020         acpi_ec_stop(ec, true);
1021         mutex_unlock(&ec->mutex);
1022 }
1023
1024 void acpi_ec_unblock_transactions(void)
1025 {
1026         /*
1027          * Allow transactions to happen again (this function is called from
1028          * atomic context during wakeup, so we don't need to acquire the mutex).
1029          */
1030         if (first_ec)
1031                 acpi_ec_start(first_ec, true);
1032 }
1033
1034 /* --------------------------------------------------------------------------
1035                                 Event Management
1036    -------------------------------------------------------------------------- */
1037 static struct acpi_ec_query_handler *
1038 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1039 {
1040         struct acpi_ec_query_handler *handler;
1041
1042         mutex_lock(&ec->mutex);
1043         list_for_each_entry(handler, &ec->list, node) {
1044                 if (value == handler->query_bit) {
1045                         kref_get(&handler->kref);
1046                         mutex_unlock(&ec->mutex);
1047                         return handler;
1048                 }
1049         }
1050         mutex_unlock(&ec->mutex);
1051         return NULL;
1052 }
1053
1054 static void acpi_ec_query_handler_release(struct kref *kref)
1055 {
1056         struct acpi_ec_query_handler *handler =
1057                 container_of(kref, struct acpi_ec_query_handler, kref);
1058
1059         kfree(handler);
1060 }
1061
1062 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1063 {
1064         kref_put(&handler->kref, acpi_ec_query_handler_release);
1065 }
1066
1067 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1068                               acpi_handle handle, acpi_ec_query_func func,
1069                               void *data)
1070 {
1071         struct acpi_ec_query_handler *handler;
1072
1073         if (!handle && !func)
1074                 return -EINVAL;
1075
1076         handler = kzalloc(sizeof(*handler), GFP_KERNEL);
1077         if (!handler)
1078                 return -ENOMEM;
1079
1080         handler->query_bit = query_bit;
1081         handler->handle = handle;
1082         handler->func = func;
1083         handler->data = data;
1084         mutex_lock(&ec->mutex);
1085         kref_init(&handler->kref);
1086         list_add(&handler->node, &ec->list);
1087         mutex_unlock(&ec->mutex);
1088
1089         return 0;
1090 }
1091 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1092
1093 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1094                                           bool remove_all, u8 query_bit)
1095 {
1096         struct acpi_ec_query_handler *handler, *tmp;
1097         LIST_HEAD(free_list);
1098
1099         mutex_lock(&ec->mutex);
1100         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1101                 /*
1102                  * When remove_all is false, only remove custom query handlers
1103                  * which have handler->func set. This is done to preserve query
1104                  * handlers discovered thru ACPI, as they should continue handling
1105                  * EC queries.
1106                  */
1107                 if (remove_all || (handler->func && handler->query_bit == query_bit)) {
1108                         list_del_init(&handler->node);
1109                         list_add(&handler->node, &free_list);
1110
1111                 }
1112         }
1113         mutex_unlock(&ec->mutex);
1114         list_for_each_entry_safe(handler, tmp, &free_list, node)
1115                 acpi_ec_put_query_handler(handler);
1116 }
1117
1118 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1119 {
1120         acpi_ec_remove_query_handlers(ec, false, query_bit);
1121         flush_workqueue(ec_query_wq);
1122 }
1123 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1124
1125 static void acpi_ec_event_processor(struct work_struct *work)
1126 {
1127         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1128         struct acpi_ec_query_handler *handler = q->handler;
1129         struct acpi_ec *ec = q->ec;
1130
1131         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1132
1133         if (handler->func)
1134                 handler->func(handler->data);
1135         else if (handler->handle)
1136                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1137
1138         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1139
1140         spin_lock_irq(&ec->lock);
1141         ec->queries_in_progress--;
1142         spin_unlock_irq(&ec->lock);
1143
1144         acpi_ec_put_query_handler(handler);
1145         kfree(q);
1146 }
1147
1148 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1149 {
1150         struct acpi_ec_query *q;
1151         struct transaction *t;
1152
1153         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1154         if (!q)
1155                 return NULL;
1156
1157         INIT_WORK(&q->work, acpi_ec_event_processor);
1158         t = &q->transaction;
1159         t->command = ACPI_EC_COMMAND_QUERY;
1160         t->rdata = pval;
1161         t->rlen = 1;
1162         q->ec = ec;
1163         return q;
1164 }
1165
1166 static int acpi_ec_submit_query(struct acpi_ec *ec)
1167 {
1168         struct acpi_ec_query *q;
1169         u8 value = 0;
1170         int result;
1171
1172         q = acpi_ec_create_query(ec, &value);
1173         if (!q)
1174                 return -ENOMEM;
1175
1176         /*
1177          * Query the EC to find out which _Qxx method we need to evaluate.
1178          * Note that successful completion of the query causes the ACPI_EC_SCI
1179          * bit to be cleared (and thus clearing the interrupt source).
1180          */
1181         result = acpi_ec_transaction(ec, &q->transaction);
1182         if (result)
1183                 goto err_exit;
1184
1185         if (!value) {
1186                 result = -ENODATA;
1187                 goto err_exit;
1188         }
1189
1190         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1191         if (!q->handler) {
1192                 result = -ENODATA;
1193                 goto err_exit;
1194         }
1195
1196         /*
1197          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1198          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1199          *
1200          * Put this log entry before queue_work() to make it appear in the log
1201          * before any other messages emitted during workqueue handling.
1202          */
1203         ec_dbg_evt("Query(0x%02x) scheduled", value);
1204
1205         spin_lock_irq(&ec->lock);
1206
1207         ec->queries_in_progress++;
1208         queue_work(ec_query_wq, &q->work);
1209
1210         spin_unlock_irq(&ec->lock);
1211
1212         return 0;
1213
1214 err_exit:
1215         kfree(q);
1216
1217         return result;
1218 }
1219
1220 static void acpi_ec_event_handler(struct work_struct *work)
1221 {
1222         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1223
1224         ec_dbg_evt("Event started");
1225
1226         spin_lock_irq(&ec->lock);
1227
1228         while (ec->events_to_process) {
1229                 spin_unlock_irq(&ec->lock);
1230
1231                 acpi_ec_submit_query(ec);
1232
1233                 spin_lock_irq(&ec->lock);
1234
1235                 ec->events_to_process--;
1236         }
1237
1238         /*
1239          * Before exit, make sure that the it will be possible to queue up the
1240          * event handling work again regardless of whether or not the query
1241          * queued up above is processed successfully.
1242          */
1243         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1244                 bool guard_timeout;
1245
1246                 acpi_ec_complete_event(ec);
1247
1248                 ec_dbg_evt("Event stopped");
1249
1250                 spin_unlock_irq(&ec->lock);
1251
1252                 guard_timeout = !!ec_guard(ec);
1253
1254                 spin_lock_irq(&ec->lock);
1255
1256                 /* Take care of SCI_EVT unless someone else is doing that. */
1257                 if (guard_timeout && !ec->curr)
1258                         advance_transaction(ec, false);
1259         } else {
1260                 acpi_ec_close_event(ec);
1261
1262                 ec_dbg_evt("Event stopped");
1263         }
1264
1265         ec->events_in_progress--;
1266
1267         spin_unlock_irq(&ec->lock);
1268 }
1269
1270 static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
1271 {
1272         /*
1273          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
1274          * changes to always trigger a GPE interrupt.
1275          *
1276          * GPE STS is a W1C register, which means:
1277          *
1278          * 1. Software can clear it without worrying about clearing the other
1279          *    GPEs' STS bits when the hardware sets them in parallel.
1280          *
1281          * 2. As long as software can ensure only clearing it when it is set,
1282          *    hardware won't set it in parallel.
1283          */
1284         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
1285                 acpi_clear_gpe(NULL, ec->gpe);
1286
1287         advance_transaction(ec, true);
1288 }
1289
1290 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1291 {
1292         unsigned long flags;
1293
1294         spin_lock_irqsave(&ec->lock, flags);
1295
1296         clear_gpe_and_advance_transaction(ec, true);
1297
1298         spin_unlock_irqrestore(&ec->lock, flags);
1299 }
1300
1301 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1302                                u32 gpe_number, void *data)
1303 {
1304         acpi_ec_handle_interrupt(data);
1305         return ACPI_INTERRUPT_HANDLED;
1306 }
1307
1308 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1309 {
1310         acpi_ec_handle_interrupt(data);
1311         return IRQ_HANDLED;
1312 }
1313
1314 /* --------------------------------------------------------------------------
1315  *                           Address Space Management
1316  * -------------------------------------------------------------------------- */
1317
1318 static acpi_status
1319 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1320                       u32 bits, u64 *value64,
1321                       void *handler_context, void *region_context)
1322 {
1323         struct acpi_ec *ec = handler_context;
1324         int result = 0, i, bytes = bits / 8;
1325         u8 *value = (u8 *)value64;
1326
1327         if ((address > 0xFF) || !value || !handler_context)
1328                 return AE_BAD_PARAMETER;
1329
1330         if (function != ACPI_READ && function != ACPI_WRITE)
1331                 return AE_BAD_PARAMETER;
1332
1333         if (ec->busy_polling || bits > 8)
1334                 acpi_ec_burst_enable(ec);
1335
1336         for (i = 0; i < bytes; ++i, ++address, ++value) {
1337                 result = (function == ACPI_READ) ?
1338                         acpi_ec_read(ec, address, value) :
1339                         acpi_ec_write(ec, address, *value);
1340                 if (result < 0)
1341                         break;
1342         }
1343
1344         if (ec->busy_polling || bits > 8)
1345                 acpi_ec_burst_disable(ec);
1346
1347         switch (result) {
1348         case -EINVAL:
1349                 return AE_BAD_PARAMETER;
1350         case -ENODEV:
1351                 return AE_NOT_FOUND;
1352         case -ETIME:
1353                 return AE_TIME;
1354         case 0:
1355                 return AE_OK;
1356         default:
1357                 return AE_ERROR;
1358         }
1359 }
1360
1361 /* --------------------------------------------------------------------------
1362  *                             Driver Interface
1363  * -------------------------------------------------------------------------- */
1364
1365 static acpi_status
1366 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1367
1368 static void acpi_ec_free(struct acpi_ec *ec)
1369 {
1370         if (first_ec == ec)
1371                 first_ec = NULL;
1372         if (boot_ec == ec)
1373                 boot_ec = NULL;
1374         kfree(ec);
1375 }
1376
1377 static struct acpi_ec *acpi_ec_alloc(void)
1378 {
1379         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1380
1381         if (!ec)
1382                 return NULL;
1383         mutex_init(&ec->mutex);
1384         init_waitqueue_head(&ec->wait);
1385         INIT_LIST_HEAD(&ec->list);
1386         spin_lock_init(&ec->lock);
1387         INIT_WORK(&ec->work, acpi_ec_event_handler);
1388         ec->timestamp = jiffies;
1389         ec->busy_polling = true;
1390         ec->polling_guard = 0;
1391         ec->gpe = -1;
1392         ec->irq = -1;
1393         return ec;
1394 }
1395
1396 static acpi_status
1397 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1398                                void *context, void **return_value)
1399 {
1400         char node_name[5];
1401         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1402         struct acpi_ec *ec = context;
1403         int value = 0;
1404         acpi_status status;
1405
1406         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1407
1408         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1409                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1410         return AE_OK;
1411 }
1412
1413 static acpi_status
1414 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1415 {
1416         acpi_status status;
1417         unsigned long long tmp = 0;
1418         struct acpi_ec *ec = context;
1419
1420         /* clear addr values, ec_parse_io_ports depend on it */
1421         ec->command_addr = ec->data_addr = 0;
1422
1423         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1424                                      ec_parse_io_ports, ec);
1425         if (ACPI_FAILURE(status))
1426                 return status;
1427         if (ec->data_addr == 0 || ec->command_addr == 0)
1428                 return AE_OK;
1429
1430         /* Get GPE bit assignment (EC events). */
1431         /* TODO: Add support for _GPE returning a package */
1432         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1433         if (ACPI_SUCCESS(status))
1434                 ec->gpe = tmp;
1435         /*
1436          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1437          * platforms which use GpioInt instead of GPE.
1438          */
1439
1440         /* Use the global lock for all EC transactions? */
1441         tmp = 0;
1442         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1443         ec->global_lock = tmp;
1444         ec->handle = handle;
1445         return AE_CTRL_TERMINATE;
1446 }
1447
1448 static bool install_gpe_event_handler(struct acpi_ec *ec)
1449 {
1450         acpi_status status;
1451
1452         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1453                                               ACPI_GPE_EDGE_TRIGGERED,
1454                                               &acpi_ec_gpe_handler, ec);
1455         if (ACPI_FAILURE(status))
1456                 return false;
1457
1458         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1459                 acpi_ec_enable_gpe(ec, true);
1460
1461         return true;
1462 }
1463
1464 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1465 {
1466         return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
1467                                     IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
1468 }
1469
1470 /**
1471  * ec_install_handlers - Install service callbacks and register query methods.
1472  * @ec: Target EC.
1473  * @device: ACPI device object corresponding to @ec.
1474  * @call_reg: If _REG should be called to notify OpRegion availability
1475  *
1476  * Install a handler for the EC address space type unless it has been installed
1477  * already.  If @device is not NULL, also look for EC query methods in the
1478  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1479  * handler for the EC, if possible.
1480  *
1481  * Return:
1482  * -ENODEV if the address space handler cannot be installed, which means
1483  *  "unable to handle transactions",
1484  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1485  * or 0 (success) otherwise.
1486  */
1487 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1488                                bool call_reg)
1489 {
1490         acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1491         acpi_status status;
1492
1493         acpi_ec_start(ec, false);
1494
1495         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1496                 acpi_ec_enter_noirq(ec);
1497                 status = acpi_install_address_space_handler_no_reg(scope_handle,
1498                                                                    ACPI_ADR_SPACE_EC,
1499                                                                    &acpi_ec_space_handler,
1500                                                                    NULL, ec);
1501                 if (ACPI_FAILURE(status)) {
1502                         acpi_ec_stop(ec, false);
1503                         return -ENODEV;
1504                 }
1505                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1506         }
1507
1508         if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1509                 acpi_execute_reg_methods(scope_handle, ACPI_ADR_SPACE_EC);
1510                 if (scope_handle != ec->handle)
1511                         acpi_execute_orphan_reg_method(ec->handle, ACPI_ADR_SPACE_EC);
1512
1513                 set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1514         }
1515
1516         if (!device)
1517                 return 0;
1518
1519         if (ec->gpe < 0) {
1520                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1521                 int irq = acpi_dev_gpio_irq_get(device, 0);
1522                 /*
1523                  * Bail out right away for deferred probing or complete the
1524                  * initialization regardless of any other errors.
1525                  */
1526                 if (irq == -EPROBE_DEFER)
1527                         return -EPROBE_DEFER;
1528                 else if (irq >= 0)
1529                         ec->irq = irq;
1530         }
1531
1532         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1533                 /* Find and register all query methods */
1534                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1535                                     acpi_ec_register_query_methods,
1536                                     NULL, ec, NULL);
1537                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1538         }
1539         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1540                 bool ready = false;
1541
1542                 if (ec->gpe >= 0)
1543                         ready = install_gpe_event_handler(ec);
1544                 else if (ec->irq >= 0)
1545                         ready = install_gpio_irq_event_handler(ec);
1546
1547                 if (ready) {
1548                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1549                         acpi_ec_leave_noirq(ec);
1550                 }
1551                 /*
1552                  * Failures to install an event handler are not fatal, because
1553                  * the EC can be polled for events.
1554                  */
1555         }
1556         /* EC is fully operational, allow queries */
1557         acpi_ec_enable_event(ec);
1558
1559         return 0;
1560 }
1561
1562 static void ec_remove_handlers(struct acpi_ec *ec)
1563 {
1564         acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1565
1566         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1567                 if (ACPI_FAILURE(acpi_remove_address_space_handler(
1568                                                 scope_handle,
1569                                                 ACPI_ADR_SPACE_EC,
1570                                                 &acpi_ec_space_handler)))
1571                         pr_err("failed to remove space handler\n");
1572                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1573         }
1574
1575         /*
1576          * Stops handling the EC transactions after removing the operation
1577          * region handler. This is required because _REG(DISCONNECT)
1578          * invoked during the removal can result in new EC transactions.
1579          *
1580          * Flushes the EC requests and thus disables the GPE before
1581          * removing the GPE handler. This is required by the current ACPICA
1582          * GPE core. ACPICA GPE core will automatically disable a GPE when
1583          * it is indicated but there is no way to handle it. So the drivers
1584          * must disable the GPEs prior to removing the GPE handlers.
1585          */
1586         acpi_ec_stop(ec, false);
1587
1588         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1589                 if (ec->gpe >= 0 &&
1590                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1591                                  &acpi_ec_gpe_handler)))
1592                         pr_err("failed to remove gpe handler\n");
1593
1594                 if (ec->irq >= 0)
1595                         free_irq(ec->irq, ec);
1596
1597                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1598         }
1599         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1600                 acpi_ec_remove_query_handlers(ec, true, 0);
1601                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1602         }
1603 }
1604
1605 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1606 {
1607         int ret;
1608
1609         /* First EC capable of handling transactions */
1610         if (!first_ec)
1611                 first_ec = ec;
1612
1613         ret = ec_install_handlers(ec, device, call_reg);
1614         if (ret) {
1615                 if (ec == first_ec)
1616                         first_ec = NULL;
1617
1618                 return ret;
1619         }
1620
1621         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1622                 ec->data_addr);
1623
1624         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1625                 if (ec->gpe >= 0)
1626                         pr_info("GPE=0x%x\n", ec->gpe);
1627                 else
1628                         pr_info("IRQ=%d\n", ec->irq);
1629         }
1630
1631         return ret;
1632 }
1633
1634 static int acpi_ec_add(struct acpi_device *device)
1635 {
1636         struct acpi_ec *ec;
1637         int ret;
1638
1639         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1640         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1641
1642         if (boot_ec && (boot_ec->handle == device->handle ||
1643             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1644                 /* Fast path: this device corresponds to the boot EC. */
1645                 ec = boot_ec;
1646         } else {
1647                 acpi_status status;
1648
1649                 ec = acpi_ec_alloc();
1650                 if (!ec)
1651                         return -ENOMEM;
1652
1653                 status = ec_parse_device(device->handle, 0, ec, NULL);
1654                 if (status != AE_CTRL_TERMINATE) {
1655                         ret = -EINVAL;
1656                         goto err;
1657                 }
1658
1659                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1660                     ec->data_addr == boot_ec->data_addr) {
1661                         /*
1662                          * Trust PNP0C09 namespace location rather than ECDT ID.
1663                          * But trust ECDT GPE rather than _GPE because of ASUS
1664                          * quirks. So do not change boot_ec->gpe to ec->gpe,
1665                          * except when the TRUST_DSDT_GPE quirk is set.
1666                          */
1667                         boot_ec->handle = ec->handle;
1668
1669                         if (EC_FLAGS_TRUST_DSDT_GPE)
1670                                 boot_ec->gpe = ec->gpe;
1671
1672                         acpi_handle_debug(ec->handle, "duplicated.\n");
1673                         acpi_ec_free(ec);
1674                         ec = boot_ec;
1675                 }
1676         }
1677
1678         ret = acpi_ec_setup(ec, device, true);
1679         if (ret)
1680                 goto err;
1681
1682         if (ec == boot_ec)
1683                 acpi_handle_info(boot_ec->handle,
1684                                  "Boot %s EC initialization complete\n",
1685                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1686
1687         acpi_handle_info(ec->handle,
1688                          "EC: Used to handle transactions and events\n");
1689
1690         device->driver_data = ec;
1691
1692         ret = !!request_region(ec->data_addr, 1, "EC data");
1693         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1694         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1695         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1696
1697         /* Reprobe devices depending on the EC */
1698         acpi_dev_clear_dependencies(device);
1699
1700         acpi_handle_debug(ec->handle, "enumerated.\n");
1701         return 0;
1702
1703 err:
1704         if (ec != boot_ec)
1705                 acpi_ec_free(ec);
1706
1707         return ret;
1708 }
1709
1710 static void acpi_ec_remove(struct acpi_device *device)
1711 {
1712         struct acpi_ec *ec;
1713
1714         if (!device)
1715                 return;
1716
1717         ec = acpi_driver_data(device);
1718         release_region(ec->data_addr, 1);
1719         release_region(ec->command_addr, 1);
1720         device->driver_data = NULL;
1721         if (ec != boot_ec) {
1722                 ec_remove_handlers(ec);
1723                 acpi_ec_free(ec);
1724         }
1725 }
1726
1727 static acpi_status
1728 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1729 {
1730         struct acpi_ec *ec = context;
1731
1732         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1733                 return AE_OK;
1734
1735         /*
1736          * The first address region returned is the data port, and
1737          * the second address region returned is the status/command
1738          * port.
1739          */
1740         if (ec->data_addr == 0)
1741                 ec->data_addr = resource->data.io.minimum;
1742         else if (ec->command_addr == 0)
1743                 ec->command_addr = resource->data.io.minimum;
1744         else
1745                 return AE_CTRL_TERMINATE;
1746
1747         return AE_OK;
1748 }
1749
1750 static const struct acpi_device_id ec_device_ids[] = {
1751         {"PNP0C09", 0},
1752         {ACPI_ECDT_HID, 0},
1753         {"", 0},
1754 };
1755
1756 /*
1757  * This function is not Windows-compatible as Windows never enumerates the
1758  * namespace EC before the main ACPI device enumeration process. It is
1759  * retained for historical reason and will be deprecated in the future.
1760  */
1761 void __init acpi_ec_dsdt_probe(void)
1762 {
1763         struct acpi_ec *ec;
1764         acpi_status status;
1765         int ret;
1766
1767         /*
1768          * If a platform has ECDT, there is no need to proceed as the
1769          * following probe is not a part of the ACPI device enumeration,
1770          * executing _STA is not safe, and thus this probe may risk of
1771          * picking up an invalid EC device.
1772          */
1773         if (boot_ec)
1774                 return;
1775
1776         ec = acpi_ec_alloc();
1777         if (!ec)
1778                 return;
1779
1780         /*
1781          * At this point, the namespace is initialized, so start to find
1782          * the namespace objects.
1783          */
1784         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1785         if (ACPI_FAILURE(status) || !ec->handle) {
1786                 acpi_ec_free(ec);
1787                 return;
1788         }
1789
1790         /*
1791          * When the DSDT EC is available, always re-configure boot EC to
1792          * have _REG evaluated. _REG can only be evaluated after the
1793          * namespace initialization.
1794          * At this point, the GPE is not fully initialized, so do not to
1795          * handle the events.
1796          */
1797         ret = acpi_ec_setup(ec, NULL, true);
1798         if (ret) {
1799                 acpi_ec_free(ec);
1800                 return;
1801         }
1802
1803         boot_ec = ec;
1804
1805         acpi_handle_info(ec->handle,
1806                          "Boot DSDT EC used to handle transactions\n");
1807 }
1808
1809 /*
1810  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1811  *
1812  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1813  * found a matching object in the namespace.
1814  *
1815  * Next, in case the DSDT EC is not functioning, it is still necessary to
1816  * provide a functional ECDT EC to handle events, so add an extra device object
1817  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1818  *
1819  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1820  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1821  */
1822 static void __init acpi_ec_ecdt_start(void)
1823 {
1824         struct acpi_table_ecdt *ecdt_ptr;
1825         acpi_handle handle;
1826         acpi_status status;
1827
1828         /* Bail out if a matching EC has been found in the namespace. */
1829         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1830                 return;
1831
1832         /* Look up the object pointed to from the ECDT in the namespace. */
1833         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1834                                 (struct acpi_table_header **)&ecdt_ptr);
1835         if (ACPI_FAILURE(status))
1836                 return;
1837
1838         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1839         if (ACPI_SUCCESS(status)) {
1840                 boot_ec->handle = handle;
1841
1842                 /* Add a special ACPI device object to represent the boot EC. */
1843                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1844         }
1845
1846         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1847 }
1848
1849 /*
1850  * On some hardware it is necessary to clear events accumulated by the EC during
1851  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1852  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1853  *
1854  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1855  *
1856  * Ideally, the EC should also be instructed NOT to accumulate events during
1857  * sleep (which Windows seems to do somehow), but the interface to control this
1858  * behaviour is not known at this time.
1859  *
1860  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1861  * however it is very likely that other Samsung models are affected.
1862  *
1863  * On systems which don't accumulate _Q events during sleep, this extra check
1864  * should be harmless.
1865  */
1866 static int ec_clear_on_resume(const struct dmi_system_id *id)
1867 {
1868         pr_debug("Detected system needing EC poll on resume.\n");
1869         EC_FLAGS_CLEAR_ON_RESUME = 1;
1870         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1871         return 0;
1872 }
1873
1874 /*
1875  * Some ECDTs contain wrong register addresses.
1876  * MSI MS-171F
1877  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1878  */
1879 static int ec_correct_ecdt(const struct dmi_system_id *id)
1880 {
1881         pr_debug("Detected system needing ECDT address correction.\n");
1882         EC_FLAGS_CORRECT_ECDT = 1;
1883         return 0;
1884 }
1885
1886 /*
1887  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1888  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1889  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1890  */
1891 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1892 {
1893         pr_debug("Detected system needing DSDT GPE setting.\n");
1894         EC_FLAGS_TRUST_DSDT_GPE = 1;
1895         return 0;
1896 }
1897
1898 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1899         {
1900                 /*
1901                  * MSI MS-171F
1902                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1903                  */
1904                 .callback = ec_correct_ecdt,
1905                 .matches = {
1906                         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1907                         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1908                 },
1909         },
1910         {
1911                 /*
1912                  * HP Pavilion Gaming Laptop 15-cx0xxx
1913                  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1914                  */
1915                 .callback = ec_honor_dsdt_gpe,
1916                 .matches = {
1917                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1918                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1919                 },
1920         },
1921         {
1922                 /*
1923                  * HP Pavilion Gaming Laptop 15-cx0041ur
1924                  */
1925                 .callback = ec_honor_dsdt_gpe,
1926                 .matches = {
1927                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1928                         DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1929                 },
1930         },
1931         {
1932                 /*
1933                  * HP Pavilion Gaming Laptop 15-dk1xxx
1934                  * https://github.com/systemd/systemd/issues/28942
1935                  */
1936                 .callback = ec_honor_dsdt_gpe,
1937                 .matches = {
1938                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1939                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
1940                 },
1941         },
1942         {
1943                 /*
1944                  * HP 250 G7 Notebook PC
1945                  */
1946                 .callback = ec_honor_dsdt_gpe,
1947                 .matches = {
1948                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1949                         DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
1950                 },
1951         },
1952         {
1953                 /*
1954                  * Samsung hardware
1955                  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1956                  */
1957                 .callback = ec_clear_on_resume,
1958                 .matches = {
1959                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
1960                 },
1961         },
1962         {}
1963 };
1964
1965 void __init acpi_ec_ecdt_probe(void)
1966 {
1967         struct acpi_table_ecdt *ecdt_ptr;
1968         struct acpi_ec *ec;
1969         acpi_status status;
1970         int ret;
1971
1972         /* Generate a boot ec context. */
1973         dmi_check_system(ec_dmi_table);
1974         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1975                                 (struct acpi_table_header **)&ecdt_ptr);
1976         if (ACPI_FAILURE(status))
1977                 return;
1978
1979         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1980                 /*
1981                  * Asus X50GL:
1982                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1983                  */
1984                 goto out;
1985         }
1986
1987         ec = acpi_ec_alloc();
1988         if (!ec)
1989                 goto out;
1990
1991         if (EC_FLAGS_CORRECT_ECDT) {
1992                 ec->command_addr = ecdt_ptr->data.address;
1993                 ec->data_addr = ecdt_ptr->control.address;
1994         } else {
1995                 ec->command_addr = ecdt_ptr->control.address;
1996                 ec->data_addr = ecdt_ptr->data.address;
1997         }
1998
1999         /*
2000          * Ignore the GPE value on Reduced Hardware platforms.
2001          * Some products have this set to an erroneous value.
2002          */
2003         if (!acpi_gbl_reduced_hardware)
2004                 ec->gpe = ecdt_ptr->gpe;
2005
2006         ec->handle = ACPI_ROOT_OBJECT;
2007
2008         /*
2009          * At this point, the namespace is not initialized, so do not find
2010          * the namespace objects, or handle the events.
2011          */
2012         ret = acpi_ec_setup(ec, NULL, false);
2013         if (ret) {
2014                 acpi_ec_free(ec);
2015                 goto out;
2016         }
2017
2018         boot_ec = ec;
2019         boot_ec_is_ecdt = true;
2020
2021         pr_info("Boot ECDT EC used to handle transactions\n");
2022
2023 out:
2024         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2025 }
2026
2027 #ifdef CONFIG_PM_SLEEP
2028 static int acpi_ec_suspend(struct device *dev)
2029 {
2030         struct acpi_ec *ec =
2031                 acpi_driver_data(to_acpi_device(dev));
2032
2033         if (!pm_suspend_no_platform() && ec_freeze_events)
2034                 acpi_ec_disable_event(ec);
2035         return 0;
2036 }
2037
2038 static int acpi_ec_suspend_noirq(struct device *dev)
2039 {
2040         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2041
2042         /*
2043          * The SCI handler doesn't run at this point, so the GPE can be
2044          * masked at the low level without side effects.
2045          */
2046         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2047             ec->gpe >= 0 && ec->reference_count >= 1)
2048                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2049
2050         acpi_ec_enter_noirq(ec);
2051
2052         return 0;
2053 }
2054
2055 static int acpi_ec_resume_noirq(struct device *dev)
2056 {
2057         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2058
2059         acpi_ec_leave_noirq(ec);
2060
2061         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2062             ec->gpe >= 0 && ec->reference_count >= 1)
2063                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2064
2065         return 0;
2066 }
2067
2068 static int acpi_ec_resume(struct device *dev)
2069 {
2070         struct acpi_ec *ec =
2071                 acpi_driver_data(to_acpi_device(dev));
2072
2073         acpi_ec_enable_event(ec);
2074         return 0;
2075 }
2076
2077 void acpi_ec_mark_gpe_for_wake(void)
2078 {
2079         if (first_ec && !ec_no_wakeup)
2080                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2081 }
2082 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2083
2084 void acpi_ec_set_gpe_wake_mask(u8 action)
2085 {
2086         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2087                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2088 }
2089
2090 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2091 {
2092         return ec->events_in_progress + ec->queries_in_progress > 0;
2093 }
2094
2095 bool acpi_ec_dispatch_gpe(void)
2096 {
2097         bool work_in_progress = false;
2098
2099         if (!first_ec)
2100                 return acpi_any_gpe_status_set(U32_MAX);
2101
2102         /*
2103          * Report wakeup if the status bit is set for any enabled GPE other
2104          * than the EC one.
2105          */
2106         if (acpi_any_gpe_status_set(first_ec->gpe))
2107                 return true;
2108
2109         /*
2110          * Cancel the SCI wakeup and process all pending events in case there
2111          * are any wakeup ones in there.
2112          *
2113          * Note that if any non-EC GPEs are active at this point, the SCI will
2114          * retrigger after the rearming in acpi_s2idle_wake(), so no events
2115          * should be missed by canceling the wakeup here.
2116          */
2117         pm_system_cancel_wakeup();
2118
2119         /*
2120          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2121          * to allow the caller to process events properly after that.
2122          */
2123         spin_lock_irq(&first_ec->lock);
2124
2125         if (acpi_ec_gpe_status_set(first_ec)) {
2126                 pm_pr_dbg("ACPI EC GPE status set\n");
2127
2128                 clear_gpe_and_advance_transaction(first_ec, false);
2129                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2130         }
2131
2132         spin_unlock_irq(&first_ec->lock);
2133
2134         if (!work_in_progress)
2135                 return false;
2136
2137         pm_pr_dbg("ACPI EC GPE dispatched\n");
2138
2139         /* Drain EC work. */
2140         do {
2141                 acpi_ec_flush_work();
2142
2143                 pm_pr_dbg("ACPI EC work flushed\n");
2144
2145                 spin_lock_irq(&first_ec->lock);
2146
2147                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2148
2149                 spin_unlock_irq(&first_ec->lock);
2150         } while (work_in_progress && !pm_wakeup_pending());
2151
2152         return false;
2153 }
2154 #endif /* CONFIG_PM_SLEEP */
2155
2156 static const struct dev_pm_ops acpi_ec_pm = {
2157         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2158         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2159 };
2160
2161 static int param_set_event_clearing(const char *val,
2162                                     const struct kernel_param *kp)
2163 {
2164         int result = 0;
2165
2166         if (!strncmp(val, "status", sizeof("status") - 1)) {
2167                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2168                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2169         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2170                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2171                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2172         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2173                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2174                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2175         } else
2176                 result = -EINVAL;
2177         return result;
2178 }
2179
2180 static int param_get_event_clearing(char *buffer,
2181                                     const struct kernel_param *kp)
2182 {
2183         switch (ec_event_clearing) {
2184         case ACPI_EC_EVT_TIMING_STATUS:
2185                 return sprintf(buffer, "status\n");
2186         case ACPI_EC_EVT_TIMING_QUERY:
2187                 return sprintf(buffer, "query\n");
2188         case ACPI_EC_EVT_TIMING_EVENT:
2189                 return sprintf(buffer, "event\n");
2190         default:
2191                 return sprintf(buffer, "invalid\n");
2192         }
2193         return 0;
2194 }
2195
2196 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2197                   NULL, 0644);
2198 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2199
2200 static struct acpi_driver acpi_ec_driver = {
2201         .name = "ec",
2202         .class = ACPI_EC_CLASS,
2203         .ids = ec_device_ids,
2204         .ops = {
2205                 .add = acpi_ec_add,
2206                 .remove = acpi_ec_remove,
2207                 },
2208         .drv.pm = &acpi_ec_pm,
2209 };
2210
2211 static void acpi_ec_destroy_workqueues(void)
2212 {
2213         if (ec_wq) {
2214                 destroy_workqueue(ec_wq);
2215                 ec_wq = NULL;
2216         }
2217         if (ec_query_wq) {
2218                 destroy_workqueue(ec_query_wq);
2219                 ec_query_wq = NULL;
2220         }
2221 }
2222
2223 static int acpi_ec_init_workqueues(void)
2224 {
2225         if (!ec_wq)
2226                 ec_wq = alloc_ordered_workqueue("kec", 0);
2227
2228         if (!ec_query_wq)
2229                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2230
2231         if (!ec_wq || !ec_query_wq) {
2232                 acpi_ec_destroy_workqueues();
2233                 return -ENODEV;
2234         }
2235         return 0;
2236 }
2237
2238 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2239         {
2240                 .matches = {
2241                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2242                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2243                 },
2244         },
2245         {
2246                 .matches = {
2247                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2248                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2249                 },
2250         },
2251         {
2252                 .matches = {
2253                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2254                         DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2255                 },
2256         },
2257         { },
2258 };
2259
2260 void __init acpi_ec_init(void)
2261 {
2262         int result;
2263
2264         result = acpi_ec_init_workqueues();
2265         if (result)
2266                 return;
2267
2268         /*
2269          * Disable EC wakeup on following systems to prevent periodic
2270          * wakeup from EC GPE.
2271          */
2272         if (dmi_check_system(acpi_ec_no_wakeup)) {
2273                 ec_no_wakeup = true;
2274                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2275         }
2276
2277         /* Driver must be registered after acpi_ec_init_workqueues(). */
2278         acpi_bus_register_driver(&acpi_ec_driver);
2279
2280         acpi_ec_ecdt_start();
2281 }
2282
2283 /* EC driver currently not unloadable */
2284 #if 0
2285 static void __exit acpi_ec_exit(void)
2286 {
2287
2288         acpi_bus_unregister_driver(&acpi_ec_driver);
2289         acpi_ec_destroy_workqueues();
2290 }
2291 #endif  /* 0 */