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         /*
 666          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
 667          * changes to always trigger a GPE interrupt.
 668          *
 669          * GPE STS is a W1C register, which means:
 670          *
 671          * 1. Software can clear it without worrying about clearing the other
 672          *    GPEs' STS bits when the hardware sets them in parallel.
 673          *
 674          * 2. As long as software can ensure only clearing it when it is set,
 675          *    hardware won't set it in parallel.
 676          */
 677         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
 678                 acpi_clear_gpe(NULL, ec->gpe);
 679
 680         status = acpi_ec_read_status(ec);
 681
 682         /*
 683          * Another IRQ or a guarded polling mode advancement is detected,
 684          * the next QR_EC submission is then allowed.
 685          */
 686         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 687                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 688                     ec->event_state == EC_EVENT_COMPLETE)
 689                         acpi_ec_close_event(ec);
 690
 691                 if (!t)
 692                         goto out;
 693         }
 694
 695         if (t->flags & ACPI_EC_COMMAND_POLL) {
 696                 if (t->wlen > t->wi) {
 697                         if (!(status & ACPI_EC_FLAG_IBF))
 698                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 699                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 700                                 acpi_ec_spurious_interrupt(ec, t);
 701                 } else if (t->rlen > t->ri) {
 702                         if (status & ACPI_EC_FLAG_OBF) {
 703                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 704                                 if (t->rlen == t->ri) {
 705                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 706                                         wakeup = true;
 707                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 708                                                 ec_dbg_evt("Command(%s) completed by hardware",
 709                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 710                                 }
 711                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 712                                 acpi_ec_spurious_interrupt(ec, t);
 713                         }
 714                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 715                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 716                         wakeup = true;
 717                 }
 718         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 719                 acpi_ec_write_cmd(ec, t->command);
 720                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 721         }
 722
 723 out:
 724         if (status & ACPI_EC_FLAG_SCI)
 725                 acpi_ec_submit_event(ec);
 726
 727         if (wakeup && interrupt)
 728                 wake_up(&ec->wait);
 729 }
 730
 731 static void start_transaction(struct acpi_ec *ec)
 732 {
 733         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 734         ec->curr->flags = 0;
 735 }
 736
 737 static int ec_guard(struct acpi_ec *ec)
 738 {
 739         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 740         unsigned long timeout = ec->timestamp + guard;
 741
 742         /* Ensure guarding period before polling EC status */
 743         do {
 744                 if (ec->busy_polling) {
 745                         /* Perform busy polling */
 746                         if (ec_transaction_completed(ec))
 747                                 return 0;
 748                         udelay(jiffies_to_usecs(guard));
 749                 } else {
 750                         /*
 751                          * Perform wait polling
 752                          * 1. Wait the transaction to be completed by the
 753                          *    GPE handler after the transaction enters
 754                          *    ACPI_EC_COMMAND_POLL state.
 755                          * 2. A special guarding logic is also required
 756                          *    for event clearing mode "event" before the
 757                          *    transaction enters ACPI_EC_COMMAND_POLL
 758                          *    state.
 759                          */
 760                         if (!ec_transaction_polled(ec) &&
 761                             !acpi_ec_guard_event(ec))
 762                                 break;
 763                         if (wait_event_timeout(ec->wait,
 764                                                ec_transaction_completed(ec),
 765                                                guard))
 766                                 return 0;
 767                 }
 768         } while (time_before(jiffies, timeout));
 769         return -ETIME;
 770 }
 771
 772 static int ec_poll(struct acpi_ec *ec)
 773 {
 774         unsigned long flags;
 775         int repeat = 5; /* number of command restarts */
 776
 777         while (repeat--) {
 778                 unsigned long delay = jiffies +
 779                         msecs_to_jiffies(ec_delay);
 780                 do {
 781                         if (!ec_guard(ec))
 782                                 return 0;
 783                         spin_lock_irqsave(&ec->lock, flags);
 784                         advance_transaction(ec, false);
 785                         spin_unlock_irqrestore(&ec->lock, flags);
 786                 } while (time_before(jiffies, delay));
 787                 pr_debug("controller reset, restart transaction\n");
 788                 spin_lock_irqsave(&ec->lock, flags);
 789                 start_transaction(ec);
 790                 spin_unlock_irqrestore(&ec->lock, flags);
 791         }
 792         return -ETIME;
 793 }
 794
 795 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 796                                         struct transaction *t)
 797 {
 798         unsigned long tmp;
 799         int ret = 0;
 800
 801         /* start transaction */
 802         spin_lock_irqsave(&ec->lock, tmp);
 803         /* Enable GPE for command processing (IBF=0/OBF=1) */
 804         if (!acpi_ec_submit_flushable_request(ec)) {
 805                 ret = -EINVAL;
 806                 goto unlock;
 807         }
 808         ec_dbg_ref(ec, "Increase command");
 809         /* following two actions should be kept atomic */
 810         ec->curr = t;
 811         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 812         start_transaction(ec);
 813         spin_unlock_irqrestore(&ec->lock, tmp);
 814
 815         ret = ec_poll(ec);
 816
 817         spin_lock_irqsave(&ec->lock, tmp);
 818         if (t->irq_count == ec_storm_threshold)
 819                 acpi_ec_unmask_events(ec);
 820         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 821         ec->curr = NULL;
 822         /* Disable GPE for command processing (IBF=0/OBF=1) */
 823         acpi_ec_complete_request(ec);
 824         ec_dbg_ref(ec, "Decrease command");
 825 unlock:
 826         spin_unlock_irqrestore(&ec->lock, tmp);
 827         return ret;
 828 }
 829
 830 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 831 {
 832         int status;
 833         u32 glk;
 834
 835         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 836                 return -EINVAL;
 837         if (t->rdata)
 838                 memset(t->rdata, 0, t->rlen);
 839
 840         mutex_lock(&ec->mutex);
 841         if (ec->global_lock) {
 842                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 843                 if (ACPI_FAILURE(status)) {
 844                         status = -ENODEV;
 845                         goto unlock;
 846                 }
 847         }
 848
 849         status = acpi_ec_transaction_unlocked(ec, t);
 850
 851         if (ec->global_lock)
 852                 acpi_release_global_lock(glk);
 853 unlock:
 854         mutex_unlock(&ec->mutex);
 855         return status;
 856 }
 857
 858 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 859 {
 860         u8 d;
 861         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 862                                 .wdata = NULL, .rdata = &d,
 863                                 .wlen = 0, .rlen = 1};
 864
 865         return acpi_ec_transaction(ec, &t);
 866 }
 867
 868 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 869 {
 870         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 871                                 .wdata = NULL, .rdata = NULL,
 872                                 .wlen = 0, .rlen = 0};
 873
 874         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 875                                 acpi_ec_transaction(ec, &t) : 0;
 876 }
 877
 878 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 879 {
 880         int result;
 881         u8 d;
 882         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 883                                 .wdata = &address, .rdata = &d,
 884                                 .wlen = 1, .rlen = 1};
 885
 886         result = acpi_ec_transaction(ec, &t);
 887         *data = d;
 888         return result;
 889 }
 890
 891 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 892 {
 893         u8 wdata[2] = { address, data };
 894         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 895                                 .wdata = wdata, .rdata = NULL,
 896                                 .wlen = 2, .rlen = 0};
 897
 898         return acpi_ec_transaction(ec, &t);
 899 }
 900
 901 int ec_read(u8 addr, u8 *val)
 902 {
 903         int err;
 904         u8 temp_data;
 905
 906         if (!first_ec)
 907                 return -ENODEV;
 908
 909         err = acpi_ec_read(first_ec, addr, &temp_data);
 910
 911         if (!err) {
 912                 *val = temp_data;
 913                 return 0;
 914         }
 915         return err;
 916 }
 917 EXPORT_SYMBOL(ec_read);
 918
 919 int ec_write(u8 addr, u8 val)
 920 {
 921         if (!first_ec)
 922                 return -ENODEV;
 923
 924         return acpi_ec_write(first_ec, addr, val);
 925 }
 926 EXPORT_SYMBOL(ec_write);
 927
 928 int ec_transaction(u8 command,
 929                    const u8 *wdata, unsigned wdata_len,
 930                    u8 *rdata, unsigned rdata_len)
 931 {
 932         struct transaction t = {.command = command,
 933                                 .wdata = wdata, .rdata = rdata,
 934                                 .wlen = wdata_len, .rlen = rdata_len};
 935
 936         if (!first_ec)
 937                 return -ENODEV;
 938
 939         return acpi_ec_transaction(first_ec, &t);
 940 }
 941 EXPORT_SYMBOL(ec_transaction);
 942
 943 /* Get the handle to the EC device */
 944 acpi_handle ec_get_handle(void)
 945 {
 946         if (!first_ec)
 947                 return NULL;
 948         return first_ec->handle;
 949 }
 950 EXPORT_SYMBOL(ec_get_handle);
 951
 952 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 953 {
 954         unsigned long flags;
 955
 956         spin_lock_irqsave(&ec->lock, flags);
 957         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 958                 ec_dbg_drv("Starting EC");
 959                 /* Enable GPE for event processing (SCI_EVT=1) */
 960                 if (!resuming) {
 961                         acpi_ec_submit_request(ec);
 962                         ec_dbg_ref(ec, "Increase driver");
 963                 }
 964                 ec_log_drv("EC started");
 965         }
 966         spin_unlock_irqrestore(&ec->lock, flags);
 967 }
 968
 969 static bool acpi_ec_stopped(struct acpi_ec *ec)
 970 {
 971         unsigned long flags;
 972         bool flushed;
 973
 974         spin_lock_irqsave(&ec->lock, flags);
 975         flushed = acpi_ec_flushed(ec);
 976         spin_unlock_irqrestore(&ec->lock, flags);
 977         return flushed;
 978 }
 979
 980 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 981 {
 982         unsigned long flags;
 983
 984         spin_lock_irqsave(&ec->lock, flags);
 985         if (acpi_ec_started(ec)) {
 986                 ec_dbg_drv("Stopping EC");
 987                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 988                 spin_unlock_irqrestore(&ec->lock, flags);
 989                 wait_event(ec->wait, acpi_ec_stopped(ec));
 990                 spin_lock_irqsave(&ec->lock, flags);
 991                 /* Disable GPE for event processing (SCI_EVT=1) */
 992                 if (!suspending) {
 993                         acpi_ec_complete_request(ec);
 994                         ec_dbg_ref(ec, "Decrease driver");
 995                 } else if (!ec_freeze_events)
 996                         __acpi_ec_disable_event(ec);
 997                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
 998                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
 999                 ec_log_drv("EC stopped");
1000         }
1001         spin_unlock_irqrestore(&ec->lock, flags);
1002 }
1003
1004 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1005 {
1006         unsigned long flags;
1007
1008         spin_lock_irqsave(&ec->lock, flags);
1009         ec->busy_polling = true;
1010         ec->polling_guard = 0;
1011         ec_log_drv("interrupt blocked");
1012         spin_unlock_irqrestore(&ec->lock, flags);
1013 }
1014
1015 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1016 {
1017         unsigned long flags;
1018
1019         spin_lock_irqsave(&ec->lock, flags);
1020         ec->busy_polling = ec_busy_polling;
1021         ec->polling_guard = ec_polling_guard;
1022         ec_log_drv("interrupt unblocked");
1023         spin_unlock_irqrestore(&ec->lock, flags);
1024 }
1025
1026 void acpi_ec_block_transactions(void)
1027 {
1028         struct acpi_ec *ec = first_ec;
1029
1030         if (!ec)
1031                 return;
1032
1033         mutex_lock(&ec->mutex);
1034         /* Prevent transactions from being carried out */
1035         acpi_ec_stop(ec, true);
1036         mutex_unlock(&ec->mutex);
1037 }
1038
1039 void acpi_ec_unblock_transactions(void)
1040 {
1041         /*
1042          * Allow transactions to happen again (this function is called from
1043          * atomic context during wakeup, so we don't need to acquire the mutex).
1044          */
1045         if (first_ec)
1046                 acpi_ec_start(first_ec, true);
1047 }
1048
1049 /* --------------------------------------------------------------------------
1050                                 Event Management
1051    -------------------------------------------------------------------------- */
1052 static struct acpi_ec_query_handler *
1053 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1054 {
1055         struct acpi_ec_query_handler *handler;
1056
1057         mutex_lock(&ec->mutex);
1058         list_for_each_entry(handler, &ec->list, node) {
1059                 if (value == handler->query_bit) {
1060                         kref_get(&handler->kref);
1061                         mutex_unlock(&ec->mutex);
1062                         return handler;
1063                 }
1064         }
1065         mutex_unlock(&ec->mutex);
1066         return NULL;
1067 }
1068
1069 static void acpi_ec_query_handler_release(struct kref *kref)
1070 {
1071         struct acpi_ec_query_handler *handler =
1072                 container_of(kref, struct acpi_ec_query_handler, kref);
1073
1074         kfree(handler);
1075 }
1076
1077 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1078 {
1079         kref_put(&handler->kref, acpi_ec_query_handler_release);
1080 }
1081
1082 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1083                               acpi_handle handle, acpi_ec_query_func func,
1084                               void *data)
1085 {
1086         struct acpi_ec_query_handler *handler =
1087             kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
1088
1089         if (!handler)
1090                 return -ENOMEM;
1091
1092         handler->query_bit = query_bit;
1093         handler->handle = handle;
1094         handler->func = func;
1095         handler->data = data;
1096         mutex_lock(&ec->mutex);
1097         kref_init(&handler->kref);
1098         list_add(&handler->node, &ec->list);
1099         mutex_unlock(&ec->mutex);
1100         return 0;
1101 }
1102 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1103
1104 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1105                                           bool remove_all, u8 query_bit)
1106 {
1107         struct acpi_ec_query_handler *handler, *tmp;
1108         LIST_HEAD(free_list);
1109
1110         mutex_lock(&ec->mutex);
1111         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1112                 if (remove_all || query_bit == handler->query_bit) {
1113                         list_del_init(&handler->node);
1114                         list_add(&handler->node, &free_list);
1115                 }
1116         }
1117         mutex_unlock(&ec->mutex);
1118         list_for_each_entry_safe(handler, tmp, &free_list, node)
1119                 acpi_ec_put_query_handler(handler);
1120 }
1121
1122 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1123 {
1124         acpi_ec_remove_query_handlers(ec, false, query_bit);
1125 }
1126 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1127
1128 static void acpi_ec_event_processor(struct work_struct *work)
1129 {
1130         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1131         struct acpi_ec_query_handler *handler = q->handler;
1132         struct acpi_ec *ec = q->ec;
1133
1134         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1135
1136         if (handler->func)
1137                 handler->func(handler->data);
1138         else if (handler->handle)
1139                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1140
1141         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1142
1143         spin_lock_irq(&ec->lock);
1144         ec->queries_in_progress--;
1145         spin_unlock_irq(&ec->lock);
1146
1147         acpi_ec_put_query_handler(handler);
1148         kfree(q);
1149 }
1150
1151 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1152 {
1153         struct acpi_ec_query *q;
1154         struct transaction *t;
1155
1156         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1157         if (!q)
1158                 return NULL;
1159
1160         INIT_WORK(&q->work, acpi_ec_event_processor);
1161         t = &q->transaction;
1162         t->command = ACPI_EC_COMMAND_QUERY;
1163         t->rdata = pval;
1164         t->rlen = 1;
1165         q->ec = ec;
1166         return q;
1167 }
1168
1169 static int acpi_ec_submit_query(struct acpi_ec *ec)
1170 {
1171         struct acpi_ec_query *q;
1172         u8 value = 0;
1173         int result;
1174
1175         q = acpi_ec_create_query(ec, &value);
1176         if (!q)
1177                 return -ENOMEM;
1178
1179         /*
1180          * Query the EC to find out which _Qxx method we need to evaluate.
1181          * Note that successful completion of the query causes the ACPI_EC_SCI
1182          * bit to be cleared (and thus clearing the interrupt source).
1183          */
1184         result = acpi_ec_transaction(ec, &q->transaction);
1185         if (result)
1186                 goto err_exit;
1187
1188         if (!value) {
1189                 result = -ENODATA;
1190                 goto err_exit;
1191         }
1192
1193         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1194         if (!q->handler) {
1195                 result = -ENODATA;
1196                 goto err_exit;
1197         }
1198
1199         /*
1200          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1201          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1202          *
1203          * Put this log entry before queue_work() to make it appear in the log
1204          * before any other messages emitted during workqueue handling.
1205          */
1206         ec_dbg_evt("Query(0x%02x) scheduled", value);
1207
1208         spin_lock_irq(&ec->lock);
1209
1210         ec->queries_in_progress++;
1211         queue_work(ec_query_wq, &q->work);
1212
1213         spin_unlock_irq(&ec->lock);
1214
1215         return 0;
1216
1217 err_exit:
1218         kfree(q);
1219
1220         return result;
1221 }
1222
1223 static void acpi_ec_event_handler(struct work_struct *work)
1224 {
1225         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1226
1227         ec_dbg_evt("Event started");
1228
1229         spin_lock_irq(&ec->lock);
1230
1231         while (ec->events_to_process) {
1232                 spin_unlock_irq(&ec->lock);
1233
1234                 acpi_ec_submit_query(ec);
1235
1236                 spin_lock_irq(&ec->lock);
1237
1238                 ec->events_to_process--;
1239         }
1240
1241         /*
1242          * Before exit, make sure that the it will be possible to queue up the
1243          * event handling work again regardless of whether or not the query
1244          * queued up above is processed successfully.
1245          */
1246         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1247                 bool guard_timeout;
1248
1249                 acpi_ec_complete_event(ec);
1250
1251                 ec_dbg_evt("Event stopped");
1252
1253                 spin_unlock_irq(&ec->lock);
1254
1255                 guard_timeout = !!ec_guard(ec);
1256
1257                 spin_lock_irq(&ec->lock);
1258
1259                 /* Take care of SCI_EVT unless someone else is doing that. */
1260                 if (guard_timeout && !ec->curr)
1261                         advance_transaction(ec, false);
1262         } else {
1263                 acpi_ec_close_event(ec);
1264
1265                 ec_dbg_evt("Event stopped");
1266         }
1267
1268         ec->events_in_progress--;
1269
1270         spin_unlock_irq(&ec->lock);
1271 }
1272
1273 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1274 {
1275         unsigned long flags;
1276
1277         spin_lock_irqsave(&ec->lock, flags);
1278         advance_transaction(ec, true);
1279         spin_unlock_irqrestore(&ec->lock, flags);
1280 }
1281
1282 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1283                                u32 gpe_number, void *data)
1284 {
1285         acpi_ec_handle_interrupt(data);
1286         return ACPI_INTERRUPT_HANDLED;
1287 }
1288
1289 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1290 {
1291         acpi_ec_handle_interrupt(data);
1292         return IRQ_HANDLED;
1293 }
1294
1295 /* --------------------------------------------------------------------------
1296  *                           Address Space Management
1297  * -------------------------------------------------------------------------- */
1298
1299 static acpi_status
1300 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1301                       u32 bits, u64 *value64,
1302                       void *handler_context, void *region_context)
1303 {
1304         struct acpi_ec *ec = handler_context;
1305         int result = 0, i, bytes = bits / 8;
1306         u8 *value = (u8 *)value64;
1307
1308         if ((address > 0xFF) || !value || !handler_context)
1309                 return AE_BAD_PARAMETER;
1310
1311         if (function != ACPI_READ && function != ACPI_WRITE)
1312                 return AE_BAD_PARAMETER;
1313
1314         if (ec->busy_polling || bits > 8)
1315                 acpi_ec_burst_enable(ec);
1316
1317         for (i = 0; i < bytes; ++i, ++address, ++value)
1318                 result = (function == ACPI_READ) ?
1319                         acpi_ec_read(ec, address, value) :
1320                         acpi_ec_write(ec, address, *value);
1321
1322         if (ec->busy_polling || bits > 8)
1323                 acpi_ec_burst_disable(ec);
1324
1325         switch (result) {
1326         case -EINVAL:
1327                 return AE_BAD_PARAMETER;
1328         case -ENODEV:
1329                 return AE_NOT_FOUND;
1330         case -ETIME:
1331                 return AE_TIME;
1332         default:
1333                 return AE_OK;
1334         }
1335 }
1336
1337 /* --------------------------------------------------------------------------
1338  *                             Driver Interface
1339  * -------------------------------------------------------------------------- */
1340
1341 static acpi_status
1342 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1343
1344 static void acpi_ec_free(struct acpi_ec *ec)
1345 {
1346         if (first_ec == ec)
1347                 first_ec = NULL;
1348         if (boot_ec == ec)
1349                 boot_ec = NULL;
1350         kfree(ec);
1351 }
1352
1353 static struct acpi_ec *acpi_ec_alloc(void)
1354 {
1355         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1356
1357         if (!ec)
1358                 return NULL;
1359         mutex_init(&ec->mutex);
1360         init_waitqueue_head(&ec->wait);
1361         INIT_LIST_HEAD(&ec->list);
1362         spin_lock_init(&ec->lock);
1363         INIT_WORK(&ec->work, acpi_ec_event_handler);
1364         ec->timestamp = jiffies;
1365         ec->busy_polling = true;
1366         ec->polling_guard = 0;
1367         ec->gpe = -1;
1368         ec->irq = -1;
1369         return ec;
1370 }
1371
1372 static acpi_status
1373 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1374                                void *context, void **return_value)
1375 {
1376         char node_name[5];
1377         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1378         struct acpi_ec *ec = context;
1379         int value = 0;
1380         acpi_status status;
1381
1382         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1383
1384         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1385                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1386         return AE_OK;
1387 }
1388
1389 static acpi_status
1390 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1391 {
1392         acpi_status status;
1393         unsigned long long tmp = 0;
1394         struct acpi_ec *ec = context;
1395
1396         /* clear addr values, ec_parse_io_ports depend on it */
1397         ec->command_addr = ec->data_addr = 0;
1398
1399         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1400                                      ec_parse_io_ports, ec);
1401         if (ACPI_FAILURE(status))
1402                 return status;
1403         if (ec->data_addr == 0 || ec->command_addr == 0)
1404                 return AE_OK;
1405
1406         /* Get GPE bit assignment (EC events). */
1407         /* TODO: Add support for _GPE returning a package */
1408         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1409         if (ACPI_SUCCESS(status))
1410                 ec->gpe = tmp;
1411         /*
1412          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1413          * platforms which use GpioInt instead of GPE.
1414          */
1415
1416         /* Use the global lock for all EC transactions? */
1417         tmp = 0;
1418         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1419         ec->global_lock = tmp;
1420         ec->handle = handle;
1421         return AE_CTRL_TERMINATE;
1422 }
1423
1424 static bool install_gpe_event_handler(struct acpi_ec *ec)
1425 {
1426         acpi_status status;
1427
1428         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1429                                               ACPI_GPE_EDGE_TRIGGERED,
1430                                               &acpi_ec_gpe_handler, ec);
1431         if (ACPI_FAILURE(status))
1432                 return false;
1433
1434         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1435                 acpi_ec_enable_gpe(ec, true);
1436
1437         return true;
1438 }
1439
1440 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1441 {
1442         return request_irq(ec->irq, acpi_ec_irq_handler, IRQF_SHARED,
1443                            "ACPI EC", ec) >= 0;
1444 }
1445
1446 /**
1447  * ec_install_handlers - Install service callbacks and register query methods.
1448  * @ec: Target EC.
1449  * @device: ACPI device object corresponding to @ec.
1450  * @call_reg: If _REG should be called to notify OpRegion availability
1451  *
1452  * Install a handler for the EC address space type unless it has been installed
1453  * already.  If @device is not NULL, also look for EC query methods in the
1454  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1455  * handler for the EC, if possible.
1456  *
1457  * Return:
1458  * -ENODEV if the address space handler cannot be installed, which means
1459  *  "unable to handle transactions",
1460  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1461  * or 0 (success) otherwise.
1462  */
1463 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1464                                bool call_reg)
1465 {
1466         acpi_status status;
1467
1468         acpi_ec_start(ec, false);
1469
1470         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1471                 acpi_ec_enter_noirq(ec);
1472                 status = acpi_install_address_space_handler_no_reg(ec->handle,
1473                                                                    ACPI_ADR_SPACE_EC,
1474                                                                    &acpi_ec_space_handler,
1475                                                                    NULL, ec);
1476                 if (ACPI_FAILURE(status)) {
1477                         acpi_ec_stop(ec, false);
1478                         return -ENODEV;
1479                 }
1480                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1481                 ec->address_space_handler_holder = ec->handle;
1482         }
1483
1484         if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1485                 acpi_execute_reg_methods(ec->handle, ACPI_ADR_SPACE_EC);
1486                 set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1487         }
1488
1489         if (!device)
1490                 return 0;
1491
1492         if (ec->gpe < 0) {
1493                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1494                 int irq = acpi_dev_gpio_irq_get(device, 0);
1495                 /*
1496                  * Bail out right away for deferred probing or complete the
1497                  * initialization regardless of any other errors.
1498                  */
1499                 if (irq == -EPROBE_DEFER)
1500                         return -EPROBE_DEFER;
1501                 else if (irq >= 0)
1502                         ec->irq = irq;
1503         }
1504
1505         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1506                 /* Find and register all query methods */
1507                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1508                                     acpi_ec_register_query_methods,
1509                                     NULL, ec, NULL);
1510                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1511         }
1512         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1513                 bool ready = false;
1514
1515                 if (ec->gpe >= 0)
1516                         ready = install_gpe_event_handler(ec);
1517                 else if (ec->irq >= 0)
1518                         ready = install_gpio_irq_event_handler(ec);
1519
1520                 if (ready) {
1521                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1522                         acpi_ec_leave_noirq(ec);
1523                 }
1524                 /*
1525                  * Failures to install an event handler are not fatal, because
1526                  * the EC can be polled for events.
1527                  */
1528         }
1529         /* EC is fully operational, allow queries */
1530         acpi_ec_enable_event(ec);
1531
1532         return 0;
1533 }
1534
1535 static void ec_remove_handlers(struct acpi_ec *ec)
1536 {
1537         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1538                 if (ACPI_FAILURE(acpi_remove_address_space_handler(
1539                                         ec->address_space_handler_holder,
1540                                         ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
1541                         pr_err("failed to remove space handler\n");
1542                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1543         }
1544
1545         /*
1546          * Stops handling the EC transactions after removing the operation
1547          * region handler. This is required because _REG(DISCONNECT)
1548          * invoked during the removal can result in new EC transactions.
1549          *
1550          * Flushes the EC requests and thus disables the GPE before
1551          * removing the GPE handler. This is required by the current ACPICA
1552          * GPE core. ACPICA GPE core will automatically disable a GPE when
1553          * it is indicated but there is no way to handle it. So the drivers
1554          * must disable the GPEs prior to removing the GPE handlers.
1555          */
1556         acpi_ec_stop(ec, false);
1557
1558         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1559                 if (ec->gpe >= 0 &&
1560                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1561                                  &acpi_ec_gpe_handler)))
1562                         pr_err("failed to remove gpe handler\n");
1563
1564                 if (ec->irq >= 0)
1565                         free_irq(ec->irq, ec);
1566
1567                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1568         }
1569         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1570                 acpi_ec_remove_query_handlers(ec, true, 0);
1571                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1572         }
1573 }
1574
1575 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1576 {
1577         int ret;
1578
1579         ret = ec_install_handlers(ec, device, call_reg);
1580         if (ret)
1581                 return ret;
1582
1583         /* First EC capable of handling transactions */
1584         if (!first_ec)
1585                 first_ec = ec;
1586
1587         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1588                 ec->data_addr);
1589
1590         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1591                 if (ec->gpe >= 0)
1592                         pr_info("GPE=0x%x\n", ec->gpe);
1593                 else
1594                         pr_info("IRQ=%d\n", ec->irq);
1595         }
1596
1597         return ret;
1598 }
1599
1600 static int acpi_ec_add(struct acpi_device *device)
1601 {
1602         struct acpi_ec *ec;
1603         int ret;
1604
1605         strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1606         strcpy(acpi_device_class(device), ACPI_EC_CLASS);
1607
1608         if (boot_ec && (boot_ec->handle == device->handle ||
1609             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1610                 /* Fast path: this device corresponds to the boot EC. */
1611                 ec = boot_ec;
1612         } else {
1613                 acpi_status status;
1614
1615                 ec = acpi_ec_alloc();
1616                 if (!ec)
1617                         return -ENOMEM;
1618
1619                 status = ec_parse_device(device->handle, 0, ec, NULL);
1620                 if (status != AE_CTRL_TERMINATE) {
1621                         ret = -EINVAL;
1622                         goto err;
1623                 }
1624
1625                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1626                     ec->data_addr == boot_ec->data_addr) {
1627                         /*
1628                          * Trust PNP0C09 namespace location rather than ECDT ID.
1629                          * But trust ECDT GPE rather than _GPE because of ASUS
1630                          * quirks. So do not change boot_ec->gpe to ec->gpe,
1631                          * except when the TRUST_DSDT_GPE quirk is set.
1632                          */
1633                         boot_ec->handle = ec->handle;
1634
1635                         if (EC_FLAGS_TRUST_DSDT_GPE)
1636                                 boot_ec->gpe = ec->gpe;
1637
1638                         acpi_handle_debug(ec->handle, "duplicated.\n");
1639                         acpi_ec_free(ec);
1640                         ec = boot_ec;
1641                 }
1642         }
1643
1644         ret = acpi_ec_setup(ec, device, true);
1645         if (ret)
1646                 goto err;
1647
1648         if (ec == boot_ec)
1649                 acpi_handle_info(boot_ec->handle,
1650                                  "Boot %s EC initialization complete\n",
1651                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1652
1653         acpi_handle_info(ec->handle,
1654                          "EC: Used to handle transactions and events\n");
1655
1656         device->driver_data = ec;
1657
1658         ret = !!request_region(ec->data_addr, 1, "EC data");
1659         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1660         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1661         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1662
1663         /* Reprobe devices depending on the EC */
1664         acpi_dev_clear_dependencies(device);
1665
1666         acpi_handle_debug(ec->handle, "enumerated.\n");
1667         return 0;
1668
1669 err:
1670         if (ec != boot_ec)
1671                 acpi_ec_free(ec);
1672
1673         return ret;
1674 }
1675
1676 static void acpi_ec_remove(struct acpi_device *device)
1677 {
1678         struct acpi_ec *ec;
1679
1680         if (!device)
1681                 return;
1682
1683         ec = acpi_driver_data(device);
1684         release_region(ec->data_addr, 1);
1685         release_region(ec->command_addr, 1);
1686         device->driver_data = NULL;
1687         if (ec != boot_ec) {
1688                 ec_remove_handlers(ec);
1689                 acpi_ec_free(ec);
1690         }
1691 }
1692
1693 static acpi_status
1694 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1695 {
1696         struct acpi_ec *ec = context;
1697
1698         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1699                 return AE_OK;
1700
1701         /*
1702          * The first address region returned is the data port, and
1703          * the second address region returned is the status/command
1704          * port.
1705          */
1706         if (ec->data_addr == 0)
1707                 ec->data_addr = resource->data.io.minimum;
1708         else if (ec->command_addr == 0)
1709                 ec->command_addr = resource->data.io.minimum;
1710         else
1711                 return AE_CTRL_TERMINATE;
1712
1713         return AE_OK;
1714 }
1715
1716 static const struct acpi_device_id ec_device_ids[] = {
1717         {"PNP0C09", 0},
1718         {ACPI_ECDT_HID, 0},
1719         {"", 0},
1720 };
1721
1722 /*
1723  * This function is not Windows-compatible as Windows never enumerates the
1724  * namespace EC before the main ACPI device enumeration process. It is
1725  * retained for historical reason and will be deprecated in the future.
1726  */
1727 void __init acpi_ec_dsdt_probe(void)
1728 {
1729         struct acpi_ec *ec;
1730         acpi_status status;
1731         int ret;
1732
1733         /*
1734          * If a platform has ECDT, there is no need to proceed as the
1735          * following probe is not a part of the ACPI device enumeration,
1736          * executing _STA is not safe, and thus this probe may risk of
1737          * picking up an invalid EC device.
1738          */
1739         if (boot_ec)
1740                 return;
1741
1742         ec = acpi_ec_alloc();
1743         if (!ec)
1744                 return;
1745
1746         /*
1747          * At this point, the namespace is initialized, so start to find
1748          * the namespace objects.
1749          */
1750         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1751         if (ACPI_FAILURE(status) || !ec->handle) {
1752                 acpi_ec_free(ec);
1753                 return;
1754         }
1755
1756         /*
1757          * When the DSDT EC is available, always re-configure boot EC to
1758          * have _REG evaluated. _REG can only be evaluated after the
1759          * namespace initialization.
1760          * At this point, the GPE is not fully initialized, so do not to
1761          * handle the events.
1762          */
1763         ret = acpi_ec_setup(ec, NULL, true);
1764         if (ret) {
1765                 acpi_ec_free(ec);
1766                 return;
1767         }
1768
1769         boot_ec = ec;
1770
1771         acpi_handle_info(ec->handle,
1772                          "Boot DSDT EC used to handle transactions\n");
1773 }
1774
1775 /*
1776  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1777  *
1778  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1779  * found a matching object in the namespace.
1780  *
1781  * Next, in case the DSDT EC is not functioning, it is still necessary to
1782  * provide a functional ECDT EC to handle events, so add an extra device object
1783  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1784  *
1785  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1786  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1787  */
1788 static void __init acpi_ec_ecdt_start(void)
1789 {
1790         struct acpi_table_ecdt *ecdt_ptr;
1791         acpi_handle handle;
1792         acpi_status status;
1793
1794         /* Bail out if a matching EC has been found in the namespace. */
1795         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1796                 return;
1797
1798         /* Look up the object pointed to from the ECDT in the namespace. */
1799         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1800                                 (struct acpi_table_header **)&ecdt_ptr);
1801         if (ACPI_FAILURE(status))
1802                 return;
1803
1804         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1805         if (ACPI_SUCCESS(status)) {
1806                 boot_ec->handle = handle;
1807
1808                 /* Add a special ACPI device object to represent the boot EC. */
1809                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1810         }
1811
1812         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1813 }
1814
1815 /*
1816  * On some hardware it is necessary to clear events accumulated by the EC during
1817  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1818  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1819  *
1820  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1821  *
1822  * Ideally, the EC should also be instructed NOT to accumulate events during
1823  * sleep (which Windows seems to do somehow), but the interface to control this
1824  * behaviour is not known at this time.
1825  *
1826  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1827  * however it is very likely that other Samsung models are affected.
1828  *
1829  * On systems which don't accumulate _Q events during sleep, this extra check
1830  * should be harmless.
1831  */
1832 static int ec_clear_on_resume(const struct dmi_system_id *id)
1833 {
1834         pr_debug("Detected system needing EC poll on resume.\n");
1835         EC_FLAGS_CLEAR_ON_RESUME = 1;
1836         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1837         return 0;
1838 }
1839
1840 /*
1841  * Some ECDTs contain wrong register addresses.
1842  * MSI MS-171F
1843  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1844  */
1845 static int ec_correct_ecdt(const struct dmi_system_id *id)
1846 {
1847         pr_debug("Detected system needing ECDT address correction.\n");
1848         EC_FLAGS_CORRECT_ECDT = 1;
1849         return 0;
1850 }
1851
1852 /*
1853  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1854  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1855  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1856  */
1857 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1858 {
1859         pr_debug("Detected system needing DSDT GPE setting.\n");
1860         EC_FLAGS_TRUST_DSDT_GPE = 1;
1861         return 0;
1862 }
1863
1864 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1865         {
1866                 /*
1867                  * MSI MS-171F
1868                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1869                  */
1870                 .callback = ec_correct_ecdt,
1871                 .matches = {
1872                         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1873                         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1874                 },
1875         },
1876         {
1877                 /*
1878                  * HP Pavilion Gaming Laptop 15-cx0xxx
1879                  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1880                  */
1881                 .callback = ec_honor_dsdt_gpe,
1882                 .matches = {
1883                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1884                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1885                 },
1886         },
1887         {
1888                 /*
1889                  * HP Pavilion Gaming Laptop 15-cx0041ur
1890                  */
1891                 .callback = ec_honor_dsdt_gpe,
1892                 .matches = {
1893                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1894                         DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1895                 },
1896         },
1897         {
1898                 /*
1899                  * Samsung hardware
1900                  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1901                  */
1902                 .callback = ec_clear_on_resume,
1903                 .matches = {
1904                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
1905                 },
1906         },
1907         {}
1908 };
1909
1910 void __init acpi_ec_ecdt_probe(void)
1911 {
1912         struct acpi_table_ecdt *ecdt_ptr;
1913         struct acpi_ec *ec;
1914         acpi_status status;
1915         int ret;
1916
1917         /* Generate a boot ec context. */
1918         dmi_check_system(ec_dmi_table);
1919         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1920                                 (struct acpi_table_header **)&ecdt_ptr);
1921         if (ACPI_FAILURE(status))
1922                 return;
1923
1924         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
1925                 /*
1926                  * Asus X50GL:
1927                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
1928                  */
1929                 goto out;
1930         }
1931
1932         ec = acpi_ec_alloc();
1933         if (!ec)
1934                 goto out;
1935
1936         if (EC_FLAGS_CORRECT_ECDT) {
1937                 ec->command_addr = ecdt_ptr->data.address;
1938                 ec->data_addr = ecdt_ptr->control.address;
1939         } else {
1940                 ec->command_addr = ecdt_ptr->control.address;
1941                 ec->data_addr = ecdt_ptr->data.address;
1942         }
1943
1944         /*
1945          * Ignore the GPE value on Reduced Hardware platforms.
1946          * Some products have this set to an erroneous value.
1947          */
1948         if (!acpi_gbl_reduced_hardware)
1949                 ec->gpe = ecdt_ptr->gpe;
1950
1951         ec->handle = ACPI_ROOT_OBJECT;
1952
1953         /*
1954          * At this point, the namespace is not initialized, so do not find
1955          * the namespace objects, or handle the events.
1956          */
1957         ret = acpi_ec_setup(ec, NULL, false);
1958         if (ret) {
1959                 acpi_ec_free(ec);
1960                 goto out;
1961         }
1962
1963         boot_ec = ec;
1964         boot_ec_is_ecdt = true;
1965
1966         pr_info("Boot ECDT EC used to handle transactions\n");
1967
1968 out:
1969         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1970 }
1971
1972 #ifdef CONFIG_PM_SLEEP
1973 static int acpi_ec_suspend(struct device *dev)
1974 {
1975         struct acpi_ec *ec =
1976                 acpi_driver_data(to_acpi_device(dev));
1977
1978         if (!pm_suspend_no_platform() && ec_freeze_events)
1979                 acpi_ec_disable_event(ec);
1980         return 0;
1981 }
1982
1983 static int acpi_ec_suspend_noirq(struct device *dev)
1984 {
1985         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
1986
1987         /*
1988          * The SCI handler doesn't run at this point, so the GPE can be
1989          * masked at the low level without side effects.
1990          */
1991         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
1992             ec->gpe >= 0 && ec->reference_count >= 1)
1993                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
1994
1995         acpi_ec_enter_noirq(ec);
1996
1997         return 0;
1998 }
1999
2000 static int acpi_ec_resume_noirq(struct device *dev)
2001 {
2002         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2003
2004         acpi_ec_leave_noirq(ec);
2005
2006         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2007             ec->gpe >= 0 && ec->reference_count >= 1)
2008                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2009
2010         return 0;
2011 }
2012
2013 static int acpi_ec_resume(struct device *dev)
2014 {
2015         struct acpi_ec *ec =
2016                 acpi_driver_data(to_acpi_device(dev));
2017
2018         acpi_ec_enable_event(ec);
2019         return 0;
2020 }
2021
2022 void acpi_ec_mark_gpe_for_wake(void)
2023 {
2024         if (first_ec && !ec_no_wakeup)
2025                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2026 }
2027 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2028
2029 void acpi_ec_set_gpe_wake_mask(u8 action)
2030 {
2031         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2032                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2033 }
2034
2035 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2036 {
2037         return ec->events_in_progress + ec->queries_in_progress > 0;
2038 }
2039
2040 bool acpi_ec_dispatch_gpe(void)
2041 {
2042         bool work_in_progress = false;
2043
2044         if (!first_ec)
2045                 return acpi_any_gpe_status_set(U32_MAX);
2046
2047         /*
2048          * Report wakeup if the status bit is set for any enabled GPE other
2049          * than the EC one.
2050          */
2051         if (acpi_any_gpe_status_set(first_ec->gpe))
2052                 return true;
2053
2054         /*
2055          * Cancel the SCI wakeup and process all pending events in case there
2056          * are any wakeup ones in there.
2057          *
2058          * Note that if any non-EC GPEs are active at this point, the SCI will
2059          * retrigger after the rearming in acpi_s2idle_wake(), so no events
2060          * should be missed by canceling the wakeup here.
2061          */
2062         pm_system_cancel_wakeup();
2063
2064         /*
2065          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2066          * to allow the caller to process events properly after that.
2067          */
2068         spin_lock_irq(&first_ec->lock);
2069
2070         if (acpi_ec_gpe_status_set(first_ec)) {
2071                 pm_pr_dbg("ACPI EC GPE status set\n");
2072
2073                 advance_transaction(first_ec, false);
2074                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2075         }
2076
2077         spin_unlock_irq(&first_ec->lock);
2078
2079         if (!work_in_progress)
2080                 return false;
2081
2082         pm_pr_dbg("ACPI EC GPE dispatched\n");
2083
2084         /* Drain EC work. */
2085         do {
2086                 acpi_ec_flush_work();
2087
2088                 pm_pr_dbg("ACPI EC work flushed\n");
2089
2090                 spin_lock_irq(&first_ec->lock);
2091
2092                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2093
2094                 spin_unlock_irq(&first_ec->lock);
2095         } while (work_in_progress && !pm_wakeup_pending());
2096
2097         return false;
2098 }
2099 #endif /* CONFIG_PM_SLEEP */
2100
2101 static const struct dev_pm_ops acpi_ec_pm = {
2102         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2103         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2104 };
2105
2106 static int param_set_event_clearing(const char *val,
2107                                     const struct kernel_param *kp)
2108 {
2109         int result = 0;
2110
2111         if (!strncmp(val, "status", sizeof("status") - 1)) {
2112                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2113                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2114         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2115                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2116                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2117         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2118                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2119                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2120         } else
2121                 result = -EINVAL;
2122         return result;
2123 }
2124
2125 static int param_get_event_clearing(char *buffer,
2126                                     const struct kernel_param *kp)
2127 {
2128         switch (ec_event_clearing) {
2129         case ACPI_EC_EVT_TIMING_STATUS:
2130                 return sprintf(buffer, "status\n");
2131         case ACPI_EC_EVT_TIMING_QUERY:
2132                 return sprintf(buffer, "query\n");
2133         case ACPI_EC_EVT_TIMING_EVENT:
2134                 return sprintf(buffer, "event\n");
2135         default:
2136                 return sprintf(buffer, "invalid\n");
2137         }
2138         return 0;
2139 }
2140
2141 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2142                   NULL, 0644);
2143 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2144
2145 static struct acpi_driver acpi_ec_driver = {
2146         .name = "ec",
2147         .class = ACPI_EC_CLASS,
2148         .ids = ec_device_ids,
2149         .ops = {
2150                 .add = acpi_ec_add,
2151                 .remove = acpi_ec_remove,
2152                 },
2153         .drv.pm = &acpi_ec_pm,
2154 };
2155
2156 static void acpi_ec_destroy_workqueues(void)
2157 {
2158         if (ec_wq) {
2159                 destroy_workqueue(ec_wq);
2160                 ec_wq = NULL;
2161         }
2162         if (ec_query_wq) {
2163                 destroy_workqueue(ec_query_wq);
2164                 ec_query_wq = NULL;
2165         }
2166 }
2167
2168 static int acpi_ec_init_workqueues(void)
2169 {
2170         if (!ec_wq)
2171                 ec_wq = alloc_ordered_workqueue("kec", 0);
2172
2173         if (!ec_query_wq)
2174                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2175
2176         if (!ec_wq || !ec_query_wq) {
2177                 acpi_ec_destroy_workqueues();
2178                 return -ENODEV;
2179         }
2180         return 0;
2181 }
2182
2183 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2184         {
2185                 .matches = {
2186                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2187                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2188                 },
2189         },
2190         {
2191                 .matches = {
2192                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2193                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2194                 },
2195         },
2196         {
2197                 .matches = {
2198                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2199                         DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2200                 },
2201         },
2202         { },
2203 };
2204
2205 void __init acpi_ec_init(void)
2206 {
2207         int result;
2208
2209         result = acpi_ec_init_workqueues();
2210         if (result)
2211                 return;
2212
2213         /*
2214          * Disable EC wakeup on following systems to prevent periodic
2215          * wakeup from EC GPE.
2216          */
2217         if (dmi_check_system(acpi_ec_no_wakeup)) {
2218                 ec_no_wakeup = true;
2219                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2220         }
2221
2222         /* Driver must be registered after acpi_ec_init_workqueues(). */
2223         acpi_bus_register_driver(&acpi_ec_driver);
2224
2225         acpi_ec_ecdt_start();
2226 }
2227
2228 /* EC driver currently not unloadable */
2229 #if 0
2230 static void __exit acpi_ec_exit(void)
2231 {
2232
2233         acpi_bus_unregister_driver(&acpi_ec_driver);
2234         acpi_ec_destroy_workqueues();
2235 }
2236 #endif  /* 0 */