drivers/acpi/ec.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  ec.c - ACPI Embedded Controller Driver (v3)
   4  *
   5  *  Copyright (C) 2001-2015 Intel Corporation
   6  *    Author: 2014, 2015 Lv Zheng <lv.zheng@intel.com>
   7  *            2006, 2007 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
   8  *            2006       Denis Sadykov <denis.m.sadykov@intel.com>
   9  *            2004       Luming Yu <luming.yu@intel.com>
  10  *            2001, 2002 Andy Grover <andrew.grover@intel.com>
  11  *            2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  12  *  Copyright (C) 2008      Alexey Starikovskiy <astarikovskiy@suse.de>
  13  */
  14
  15 /* Uncomment next line to get verbose printout */
  16 /* #define DEBUG */
  17 #define pr_fmt(fmt) "ACPI: EC: " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/types.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/list.h>
  26 #include <linux/printk.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/slab.h>
  29 #include <linux/string.h>
  30 #include <linux/suspend.h>
  31 #include <linux/acpi.h>
  32 #include <linux/dmi.h>
  33 #include <asm/io.h>
  34
  35 #include "internal.h"
  36
  37 #define ACPI_EC_CLASS                   "embedded_controller"
  38 #define ACPI_EC_DEVICE_NAME             "Embedded Controller"
  39
  40 /* EC status register */
  41 #define ACPI_EC_FLAG_OBF        0x01    /* Output buffer full */
  42 #define ACPI_EC_FLAG_IBF        0x02    /* Input buffer full */
  43 #define ACPI_EC_FLAG_CMD        0x08    /* Input buffer contains a command */
  44 #define ACPI_EC_FLAG_BURST      0x10    /* burst mode */
  45 #define ACPI_EC_FLAG_SCI        0x20    /* EC-SCI occurred */
  46
  47 /*
  48  * The SCI_EVT clearing timing is not defined by the ACPI specification.
  49  * This leads to lots of practical timing issues for the host EC driver.
  50  * The following variations are defined (from the target EC firmware's
  51  * perspective):
  52  * STATUS: After indicating SCI_EVT edge triggered IRQ to the host, the
  53  *         target can clear SCI_EVT at any time so long as the host can see
  54  *         the indication by reading the status register (EC_SC). So the
  55  *         host should re-check SCI_EVT after the first time the SCI_EVT
  56  *         indication is seen, which is the same time the query request
  57  *         (QR_EC) is written to the command register (EC_CMD). SCI_EVT set
  58  *         at any later time could indicate another event. Normally such
  59  *         kind of EC firmware has implemented an event queue and will
  60  *         return 0x00 to indicate "no outstanding event".
  61  * QUERY: After seeing the query request (QR_EC) written to the command
  62  *        register (EC_CMD) by the host and having prepared the responding
  63  *        event value in the data register (EC_DATA), the target can safely
  64  *        clear SCI_EVT because the target can confirm that the current
  65  *        event is being handled by the host. The host then should check
  66  *        SCI_EVT right after reading the event response from the data
  67  *        register (EC_DATA).
  68  * EVENT: After seeing the event response read from the data register
  69  *        (EC_DATA) by the host, the target can clear SCI_EVT. As the
  70  *        target requires time to notice the change in the data register
  71  *        (EC_DATA), the host may be required to wait additional guarding
  72  *        time before checking the SCI_EVT again. Such guarding may not be
  73  *        necessary if the host is notified via another IRQ.
  74  */
  75 #define ACPI_EC_EVT_TIMING_STATUS       0x00
  76 #define ACPI_EC_EVT_TIMING_QUERY        0x01
  77 #define ACPI_EC_EVT_TIMING_EVENT        0x02
  78
  79 /* EC commands */
  80 enum ec_command {
  81         ACPI_EC_COMMAND_READ = 0x80,
  82         ACPI_EC_COMMAND_WRITE = 0x81,
  83         ACPI_EC_BURST_ENABLE = 0x82,
  84         ACPI_EC_BURST_DISABLE = 0x83,
  85         ACPI_EC_COMMAND_QUERY = 0x84,
  86 };
  87
  88 #define ACPI_EC_DELAY           500     /* Wait 500ms max. during EC ops */
  89 #define ACPI_EC_UDELAY_GLK      1000    /* Wait 1ms max. to get global lock */
  90 #define ACPI_EC_UDELAY_POLL     550     /* Wait 1ms for EC transaction polling */
  91 #define ACPI_EC_CLEAR_MAX       100     /* Maximum number of events to query
  92                                          * when trying to clear the EC */
  93 #define ACPI_EC_MAX_QUERIES     16      /* Maximum number of parallel queries */
  94
  95 enum {
  96         EC_FLAGS_QUERY_ENABLED,         /* Query is enabled */
  97         EC_FLAGS_EVENT_HANDLER_INSTALLED,       /* Event handler installed */
  98         EC_FLAGS_EC_HANDLER_INSTALLED,  /* OpReg handler installed */
  99         EC_FLAGS_EC_REG_CALLED,         /* OpReg ACPI _REG method called */
 100         EC_FLAGS_QUERY_METHODS_INSTALLED, /* _Qxx handlers installed */
 101         EC_FLAGS_STARTED,               /* Driver is started */
 102         EC_FLAGS_STOPPED,               /* Driver is stopped */
 103         EC_FLAGS_EVENTS_MASKED,         /* Events masked */
 104 };
 105
 106 #define ACPI_EC_COMMAND_POLL            0x01 /* Available for command byte */
 107 #define ACPI_EC_COMMAND_COMPLETE        0x02 /* Completed last byte */
 108
 109 /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
 110 static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 111 module_param(ec_delay, uint, 0644);
 112 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 113
 114 static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
 115 module_param(ec_max_queries, uint, 0644);
 116 MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
 117
 118 static bool ec_busy_polling __read_mostly;
 119 module_param(ec_busy_polling, bool, 0644);
 120 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
 121
 122 static unsigned int ec_polling_guard __read_mostly = ACPI_EC_UDELAY_POLL;
 123 module_param(ec_polling_guard, uint, 0644);
 124 MODULE_PARM_DESC(ec_polling_guard, "Guard time(us) between EC accesses in polling modes");
 125
 126 static unsigned int ec_event_clearing __read_mostly = ACPI_EC_EVT_TIMING_QUERY;
 127
 128 /*
 129  * If the number of false interrupts per one transaction exceeds
 130  * this threshold, will think there is a GPE storm happened and
 131  * will disable the GPE for normal transaction.
 132  */
 133 static unsigned int ec_storm_threshold  __read_mostly = 8;
 134 module_param(ec_storm_threshold, uint, 0644);
 135 MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
 136
 137 static bool ec_freeze_events __read_mostly;
 138 module_param(ec_freeze_events, bool, 0644);
 139 MODULE_PARM_DESC(ec_freeze_events, "Disabling event handling during suspend/resume");
 140
 141 static bool ec_no_wakeup __read_mostly;
 142 module_param(ec_no_wakeup, bool, 0644);
 143 MODULE_PARM_DESC(ec_no_wakeup, "Do not wake up from suspend-to-idle");
 144
 145 struct acpi_ec_query_handler {
 146         struct list_head node;
 147         acpi_ec_query_func func;
 148         acpi_handle handle;
 149         void *data;
 150         u8 query_bit;
 151         struct kref kref;
 152 };
 153
 154 struct transaction {
 155         const u8 *wdata;
 156         u8 *rdata;
 157         unsigned short irq_count;
 158         u8 command;
 159         u8 wi;
 160         u8 ri;
 161         u8 wlen;
 162         u8 rlen;
 163         u8 flags;
 164 };
 165
 166 struct acpi_ec_query {
 167         struct transaction transaction;
 168         struct work_struct work;
 169         struct acpi_ec_query_handler *handler;
 170         struct acpi_ec *ec;
 171 };
 172
 173 static int acpi_ec_submit_query(struct acpi_ec *ec);
 174 static void advance_transaction(struct acpi_ec *ec, bool interrupt);
 175 static void acpi_ec_event_handler(struct work_struct *work);
 176
 177 struct acpi_ec *first_ec;
 178 EXPORT_SYMBOL(first_ec);
 179
 180 static struct acpi_ec *boot_ec;
 181 static bool boot_ec_is_ecdt;
 182 static struct workqueue_struct *ec_wq;
 183 static struct workqueue_struct *ec_query_wq;
 184
 185 static int EC_FLAGS_CORRECT_ECDT; /* Needs ECDT port address correction */
 186 static int EC_FLAGS_TRUST_DSDT_GPE; /* Needs DSDT GPE as correction setting */
 187 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
 188
 189 /* --------------------------------------------------------------------------
 190  *                           Logging/Debugging
 191  * -------------------------------------------------------------------------- */
 192
 193 /*
 194  * Splitters used by the developers to track the boundary of the EC
 195  * handling processes.
 196  */
 197 #ifdef DEBUG
 198 #define EC_DBG_SEP      " "
 199 #define EC_DBG_DRV      "+++++"
 200 #define EC_DBG_STM      "====="
 201 #define EC_DBG_REQ      "*****"
 202 #define EC_DBG_EVT      "#####"
 203 #else
 204 #define EC_DBG_SEP      ""
 205 #define EC_DBG_DRV
 206 #define EC_DBG_STM
 207 #define EC_DBG_REQ
 208 #define EC_DBG_EVT
 209 #endif
 210
 211 #define ec_log_raw(fmt, ...) \
 212         pr_info(fmt "\n", ##__VA_ARGS__)
 213 #define ec_dbg_raw(fmt, ...) \
 214         pr_debug(fmt "\n", ##__VA_ARGS__)
 215 #define ec_log(filter, fmt, ...) \
 216         ec_log_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 217 #define ec_dbg(filter, fmt, ...) \
 218         ec_dbg_raw(filter EC_DBG_SEP fmt EC_DBG_SEP filter, ##__VA_ARGS__)
 219
 220 #define ec_log_drv(fmt, ...) \
 221         ec_log(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 222 #define ec_dbg_drv(fmt, ...) \
 223         ec_dbg(EC_DBG_DRV, fmt, ##__VA_ARGS__)
 224 #define ec_dbg_stm(fmt, ...) \
 225         ec_dbg(EC_DBG_STM, fmt, ##__VA_ARGS__)
 226 #define ec_dbg_req(fmt, ...) \
 227         ec_dbg(EC_DBG_REQ, fmt, ##__VA_ARGS__)
 228 #define ec_dbg_evt(fmt, ...) \
 229         ec_dbg(EC_DBG_EVT, fmt, ##__VA_ARGS__)
 230 #define ec_dbg_ref(ec, fmt, ...) \
 231         ec_dbg_raw("%lu: " fmt, ec->reference_count, ## __VA_ARGS__)
 232
 233 /* --------------------------------------------------------------------------
 234  *                           Device Flags
 235  * -------------------------------------------------------------------------- */
 236
 237 static bool acpi_ec_started(struct acpi_ec *ec)
 238 {
 239         return test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 240                !test_bit(EC_FLAGS_STOPPED, &ec->flags);
 241 }
 242
 243 static bool acpi_ec_event_enabled(struct acpi_ec *ec)
 244 {
 245         /*
 246          * There is an OSPM early stage logic. During the early stages
 247          * (boot/resume), OSPMs shouldn't enable the event handling, only
 248          * the EC transactions are allowed to be performed.
 249          */
 250         if (!test_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 251                 return false;
 252         /*
 253          * However, disabling the event handling is experimental for late
 254          * stage (suspend), and is controlled by the boot parameter of
 255          * "ec_freeze_events":
 256          * 1. true:  The EC event handling is disabled before entering
 257          *           the noirq stage.
 258          * 2. false: The EC event handling is automatically disabled as
 259          *           soon as the EC driver is stopped.
 260          */
 261         if (ec_freeze_events)
 262                 return acpi_ec_started(ec);
 263         else
 264                 return test_bit(EC_FLAGS_STARTED, &ec->flags);
 265 }
 266
 267 static bool acpi_ec_flushed(struct acpi_ec *ec)
 268 {
 269         return ec->reference_count == 1;
 270 }
 271
 272 /* --------------------------------------------------------------------------
 273  *                           EC Registers
 274  * -------------------------------------------------------------------------- */
 275
 276 static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
 277 {
 278         u8 x = inb(ec->command_addr);
 279
 280         ec_dbg_raw("EC_SC(R) = 0x%2.2x "
 281                    "SCI_EVT=%d BURST=%d CMD=%d IBF=%d OBF=%d",
 282                    x,
 283                    !!(x & ACPI_EC_FLAG_SCI),
 284                    !!(x & ACPI_EC_FLAG_BURST),
 285                    !!(x & ACPI_EC_FLAG_CMD),
 286                    !!(x & ACPI_EC_FLAG_IBF),
 287                    !!(x & ACPI_EC_FLAG_OBF));
 288         return x;
 289 }
 290
 291 static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
 292 {
 293         u8 x = inb(ec->data_addr);
 294
 295         ec->timestamp = jiffies;
 296         ec_dbg_raw("EC_DATA(R) = 0x%2.2x", x);
 297         return x;
 298 }
 299
 300 static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
 301 {
 302         ec_dbg_raw("EC_SC(W) = 0x%2.2x", command);
 303         outb(command, ec->command_addr);
 304         ec->timestamp = jiffies;
 305 }
 306
 307 static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
 308 {
 309         ec_dbg_raw("EC_DATA(W) = 0x%2.2x", data);
 310         outb(data, ec->data_addr);
 311         ec->timestamp = jiffies;
 312 }
 313
 314 #if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG)
 315 static const char *acpi_ec_cmd_string(u8 cmd)
 316 {
 317         switch (cmd) {
 318         case 0x80:
 319                 return "RD_EC";
 320         case 0x81:
 321                 return "WR_EC";
 322         case 0x82:
 323                 return "BE_EC";
 324         case 0x83:
 325                 return "BD_EC";
 326         case 0x84:
 327                 return "QR_EC";
 328         }
 329         return "UNKNOWN";
 330 }
 331 #else
 332 #define acpi_ec_cmd_string(cmd)         "UNDEF"
 333 #endif
 334
 335 /* --------------------------------------------------------------------------
 336  *                           GPE Registers
 337  * -------------------------------------------------------------------------- */
 338
 339 static inline bool acpi_ec_gpe_status_set(struct acpi_ec *ec)
 340 {
 341         acpi_event_status gpe_status = 0;
 342
 343         (void)acpi_get_gpe_status(NULL, ec->gpe, &gpe_status);
 344         return !!(gpe_status & ACPI_EVENT_FLAG_STATUS_SET);
 345 }
 346
 347 static inline void acpi_ec_enable_gpe(struct acpi_ec *ec, bool open)
 348 {
 349         if (open)
 350                 acpi_enable_gpe(NULL, ec->gpe);
 351         else {
 352                 BUG_ON(ec->reference_count < 1);
 353                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
 354         }
 355         if (acpi_ec_gpe_status_set(ec)) {
 356                 /*
 357                  * On some platforms, EN=1 writes cannot trigger GPE. So
 358                  * software need to manually trigger a pseudo GPE event on
 359                  * EN=1 writes.
 360                  */
 361                 ec_dbg_raw("Polling quirk");
 362                 advance_transaction(ec, false);
 363         }
 364 }
 365
 366 static inline void acpi_ec_disable_gpe(struct acpi_ec *ec, bool close)
 367 {
 368         if (close)
 369                 acpi_disable_gpe(NULL, ec->gpe);
 370         else {
 371                 BUG_ON(ec->reference_count < 1);
 372                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
 373         }
 374 }
 375
 376 /* --------------------------------------------------------------------------
 377  *                           Transaction Management
 378  * -------------------------------------------------------------------------- */
 379
 380 static void acpi_ec_submit_request(struct acpi_ec *ec)
 381 {
 382         ec->reference_count++;
 383         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 384             ec->gpe >= 0 && ec->reference_count == 1)
 385                 acpi_ec_enable_gpe(ec, true);
 386 }
 387
 388 static void acpi_ec_complete_request(struct acpi_ec *ec)
 389 {
 390         bool flushed = false;
 391
 392         ec->reference_count--;
 393         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags) &&
 394             ec->gpe >= 0 && ec->reference_count == 0)
 395                 acpi_ec_disable_gpe(ec, true);
 396         flushed = acpi_ec_flushed(ec);
 397         if (flushed)
 398                 wake_up(&ec->wait);
 399 }
 400
 401 static void acpi_ec_mask_events(struct acpi_ec *ec)
 402 {
 403         if (!test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 404                 if (ec->gpe >= 0)
 405                         acpi_ec_disable_gpe(ec, false);
 406                 else
 407                         disable_irq_nosync(ec->irq);
 408
 409                 ec_dbg_drv("Polling enabled");
 410                 set_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 411         }
 412 }
 413
 414 static void acpi_ec_unmask_events(struct acpi_ec *ec)
 415 {
 416         if (test_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags)) {
 417                 clear_bit(EC_FLAGS_EVENTS_MASKED, &ec->flags);
 418                 if (ec->gpe >= 0)
 419                         acpi_ec_enable_gpe(ec, false);
 420                 else
 421                         enable_irq(ec->irq);
 422
 423                 ec_dbg_drv("Polling disabled");
 424         }
 425 }
 426
 427 /*
 428  * acpi_ec_submit_flushable_request() - Increase the reference count unless
 429  *                                      the flush operation is not in
 430  *                                      progress
 431  * @ec: the EC device
 432  *
 433  * This function must be used before taking a new action that should hold
 434  * the reference count.  If this function returns false, then the action
 435  * must be discarded or it will prevent the flush operation from being
 436  * completed.
 437  */
 438 static bool acpi_ec_submit_flushable_request(struct acpi_ec *ec)
 439 {
 440         if (!acpi_ec_started(ec))
 441                 return false;
 442         acpi_ec_submit_request(ec);
 443         return true;
 444 }
 445
 446 static void acpi_ec_submit_event(struct acpi_ec *ec)
 447 {
 448         /*
 449          * It is safe to mask the events here, because acpi_ec_close_event()
 450          * will run at least once after this.
 451          */
 452         acpi_ec_mask_events(ec);
 453         if (!acpi_ec_event_enabled(ec))
 454                 return;
 455
 456         if (ec->event_state != EC_EVENT_READY)
 457                 return;
 458
 459         ec_dbg_evt("Command(%s) submitted/blocked",
 460                    acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 461
 462         ec->event_state = EC_EVENT_IN_PROGRESS;
 463         /*
 464          * If events_to_process is greater than 0 at this point, the while ()
 465          * loop in acpi_ec_event_handler() is still running and incrementing
 466          * events_to_process will cause it to invoke acpi_ec_submit_query() once
 467          * more, so it is not necessary to queue up the event work to start the
 468          * same loop again.
 469          */
 470         if (ec->events_to_process++ > 0)
 471                 return;
 472
 473         ec->events_in_progress++;
 474         queue_work(ec_wq, &ec->work);
 475 }
 476
 477 static void acpi_ec_complete_event(struct acpi_ec *ec)
 478 {
 479         if (ec->event_state == EC_EVENT_IN_PROGRESS)
 480                 ec->event_state = EC_EVENT_COMPLETE;
 481 }
 482
 483 static void acpi_ec_close_event(struct acpi_ec *ec)
 484 {
 485         if (ec->event_state != EC_EVENT_READY)
 486                 ec_dbg_evt("Command(%s) unblocked",
 487                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 488
 489         ec->event_state = EC_EVENT_READY;
 490         acpi_ec_unmask_events(ec);
 491 }
 492
 493 static inline void __acpi_ec_enable_event(struct acpi_ec *ec)
 494 {
 495         if (!test_and_set_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 496                 ec_log_drv("event unblocked");
 497         /*
 498          * Unconditionally invoke this once after enabling the event
 499          * handling mechanism to detect the pending events.
 500          */
 501         advance_transaction(ec, false);
 502 }
 503
 504 static inline void __acpi_ec_disable_event(struct acpi_ec *ec)
 505 {
 506         if (test_and_clear_bit(EC_FLAGS_QUERY_ENABLED, &ec->flags))
 507                 ec_log_drv("event blocked");
 508 }
 509
 510 /*
 511  * Process _Q events that might have accumulated in the EC.
 512  * Run with locked ec mutex.
 513  */
 514 static void acpi_ec_clear(struct acpi_ec *ec)
 515 {
 516         int i;
 517
 518         for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
 519                 if (acpi_ec_submit_query(ec))
 520                         break;
 521         }
 522         if (unlikely(i == ACPI_EC_CLEAR_MAX))
 523                 pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
 524         else
 525                 pr_info("%d stale EC events cleared\n", i);
 526 }
 527
 528 static void acpi_ec_enable_event(struct acpi_ec *ec)
 529 {
 530         unsigned long flags;
 531
 532         spin_lock_irqsave(&ec->lock, flags);
 533         if (acpi_ec_started(ec))
 534                 __acpi_ec_enable_event(ec);
 535         spin_unlock_irqrestore(&ec->lock, flags);
 536
 537         /* Drain additional events if hardware requires that */
 538         if (EC_FLAGS_CLEAR_ON_RESUME)
 539                 acpi_ec_clear(ec);
 540 }
 541
 542 #ifdef CONFIG_PM_SLEEP
 543 static void __acpi_ec_flush_work(void)
 544 {
 545         flush_workqueue(ec_wq); /* flush ec->work */
 546         flush_workqueue(ec_query_wq); /* flush queries */
 547 }
 548
 549 static void acpi_ec_disable_event(struct acpi_ec *ec)
 550 {
 551         unsigned long flags;
 552
 553         spin_lock_irqsave(&ec->lock, flags);
 554         __acpi_ec_disable_event(ec);
 555         spin_unlock_irqrestore(&ec->lock, flags);
 556
 557         /*
 558          * When ec_freeze_events is true, we need to flush events in
 559          * the proper position before entering the noirq stage.
 560          */
 561         __acpi_ec_flush_work();
 562 }
 563
 564 void acpi_ec_flush_work(void)
 565 {
 566         /* Without ec_wq there is nothing to flush. */
 567         if (!ec_wq)
 568                 return;
 569
 570         __acpi_ec_flush_work();
 571 }
 572 #endif /* CONFIG_PM_SLEEP */
 573
 574 static bool acpi_ec_guard_event(struct acpi_ec *ec)
 575 {
 576         unsigned long flags;
 577         bool guarded;
 578
 579         spin_lock_irqsave(&ec->lock, flags);
 580         /*
 581          * If firmware SCI_EVT clearing timing is "event", we actually
 582          * don't know when the SCI_EVT will be cleared by firmware after
 583          * evaluating _Qxx, so we need to re-check SCI_EVT after waiting an
 584          * acceptable period.
 585          *
 586          * The guarding period is applicable if the event state is not
 587          * EC_EVENT_READY, but otherwise if the current transaction is of the
 588          * ACPI_EC_COMMAND_QUERY type, the guarding should have elapsed already
 589          * and it should not be applied to let the transaction transition into
 590          * the ACPI_EC_COMMAND_POLL state immediately.
 591          */
 592         guarded = ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 593                 ec->event_state != EC_EVENT_READY &&
 594                 (!ec->curr || ec->curr->command != ACPI_EC_COMMAND_QUERY);
 595         spin_unlock_irqrestore(&ec->lock, flags);
 596         return guarded;
 597 }
 598
 599 static int ec_transaction_polled(struct acpi_ec *ec)
 600 {
 601         unsigned long flags;
 602         int ret = 0;
 603
 604         spin_lock_irqsave(&ec->lock, flags);
 605         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_POLL))
 606                 ret = 1;
 607         spin_unlock_irqrestore(&ec->lock, flags);
 608         return ret;
 609 }
 610
 611 static int ec_transaction_completed(struct acpi_ec *ec)
 612 {
 613         unsigned long flags;
 614         int ret = 0;
 615
 616         spin_lock_irqsave(&ec->lock, flags);
 617         if (ec->curr && (ec->curr->flags & ACPI_EC_COMMAND_COMPLETE))
 618                 ret = 1;
 619         spin_unlock_irqrestore(&ec->lock, flags);
 620         return ret;
 621 }
 622
 623 static inline void ec_transaction_transition(struct acpi_ec *ec, unsigned long flag)
 624 {
 625         ec->curr->flags |= flag;
 626
 627         if (ec->curr->command != ACPI_EC_COMMAND_QUERY)
 628                 return;
 629
 630         switch (ec_event_clearing) {
 631         case ACPI_EC_EVT_TIMING_STATUS:
 632                 if (flag == ACPI_EC_COMMAND_POLL)
 633                         acpi_ec_close_event(ec);
 634
 635                 return;
 636
 637         case ACPI_EC_EVT_TIMING_QUERY:
 638                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 639                         acpi_ec_close_event(ec);
 640
 641                 return;
 642
 643         case ACPI_EC_EVT_TIMING_EVENT:
 644                 if (flag == ACPI_EC_COMMAND_COMPLETE)
 645                         acpi_ec_complete_event(ec);
 646         }
 647 }
 648
 649 static void acpi_ec_spurious_interrupt(struct acpi_ec *ec, struct transaction *t)
 650 {
 651         if (t->irq_count < ec_storm_threshold)
 652                 ++t->irq_count;
 653
 654         /* Trigger if the threshold is 0 too. */
 655         if (t->irq_count == ec_storm_threshold)
 656                 acpi_ec_mask_events(ec);
 657 }
 658
 659 static void advance_transaction(struct acpi_ec *ec, bool interrupt)
 660 {
 661         struct transaction *t = ec->curr;
 662         bool wakeup = false;
 663         u8 status;
 664
 665         ec_dbg_stm("%s (%d)", interrupt ? "IRQ" : "TASK", smp_processor_id());
 666
 667         status = acpi_ec_read_status(ec);
 668
 669         /*
 670          * Another IRQ or a guarded polling mode advancement is detected,
 671          * the next QR_EC submission is then allowed.
 672          */
 673         if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) {
 674                 if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT &&
 675                     ec->event_state == EC_EVENT_COMPLETE)
 676                         acpi_ec_close_event(ec);
 677
 678                 if (!t)
 679                         goto out;
 680         }
 681
 682         if (t->flags & ACPI_EC_COMMAND_POLL) {
 683                 if (t->wlen > t->wi) {
 684                         if (!(status & ACPI_EC_FLAG_IBF))
 685                                 acpi_ec_write_data(ec, t->wdata[t->wi++]);
 686                         else if (interrupt && !(status & ACPI_EC_FLAG_SCI))
 687                                 acpi_ec_spurious_interrupt(ec, t);
 688                 } else if (t->rlen > t->ri) {
 689                         if (status & ACPI_EC_FLAG_OBF) {
 690                                 t->rdata[t->ri++] = acpi_ec_read_data(ec);
 691                                 if (t->rlen == t->ri) {
 692                                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 693                                         wakeup = true;
 694                                         if (t->command == ACPI_EC_COMMAND_QUERY)
 695                                                 ec_dbg_evt("Command(%s) completed by hardware",
 696                                                            acpi_ec_cmd_string(ACPI_EC_COMMAND_QUERY));
 697                                 }
 698                         } else if (interrupt && !(status & ACPI_EC_FLAG_SCI)) {
 699                                 acpi_ec_spurious_interrupt(ec, t);
 700                         }
 701                 } else if (t->wlen == t->wi && !(status & ACPI_EC_FLAG_IBF)) {
 702                         ec_transaction_transition(ec, ACPI_EC_COMMAND_COMPLETE);
 703                         wakeup = true;
 704                 }
 705         } else if (!(status & ACPI_EC_FLAG_IBF)) {
 706                 acpi_ec_write_cmd(ec, t->command);
 707                 ec_transaction_transition(ec, ACPI_EC_COMMAND_POLL);
 708         }
 709
 710 out:
 711         if (status & ACPI_EC_FLAG_SCI)
 712                 acpi_ec_submit_event(ec);
 713
 714         if (wakeup && interrupt)
 715                 wake_up(&ec->wait);
 716 }
 717
 718 static void start_transaction(struct acpi_ec *ec)
 719 {
 720         ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
 721         ec->curr->flags = 0;
 722 }
 723
 724 static int ec_guard(struct acpi_ec *ec)
 725 {
 726         unsigned long guard = usecs_to_jiffies(ec->polling_guard);
 727         unsigned long timeout = ec->timestamp + guard;
 728
 729         /* Ensure guarding period before polling EC status */
 730         do {
 731                 if (ec->busy_polling) {
 732                         /* Perform busy polling */
 733                         if (ec_transaction_completed(ec))
 734                                 return 0;
 735                         udelay(jiffies_to_usecs(guard));
 736                 } else {
 737                         /*
 738                          * Perform wait polling
 739                          * 1. Wait the transaction to be completed by the
 740                          *    GPE handler after the transaction enters
 741                          *    ACPI_EC_COMMAND_POLL state.
 742                          * 2. A special guarding logic is also required
 743                          *    for event clearing mode "event" before the
 744                          *    transaction enters ACPI_EC_COMMAND_POLL
 745                          *    state.
 746                          */
 747                         if (!ec_transaction_polled(ec) &&
 748                             !acpi_ec_guard_event(ec))
 749                                 break;
 750                         if (wait_event_timeout(ec->wait,
 751                                                ec_transaction_completed(ec),
 752                                                guard))
 753                                 return 0;
 754                 }
 755         } while (time_before(jiffies, timeout));
 756         return -ETIME;
 757 }
 758
 759 static int ec_poll(struct acpi_ec *ec)
 760 {
 761         unsigned long flags;
 762         int repeat = 5; /* number of command restarts */
 763
 764         while (repeat--) {
 765                 unsigned long delay = jiffies +
 766                         msecs_to_jiffies(ec_delay);
 767                 do {
 768                         if (!ec_guard(ec))
 769                                 return 0;
 770                         spin_lock_irqsave(&ec->lock, flags);
 771                         advance_transaction(ec, false);
 772                         spin_unlock_irqrestore(&ec->lock, flags);
 773                 } while (time_before(jiffies, delay));
 774                 pr_debug("controller reset, restart transaction\n");
 775                 spin_lock_irqsave(&ec->lock, flags);
 776                 start_transaction(ec);
 777                 spin_unlock_irqrestore(&ec->lock, flags);
 778         }
 779         return -ETIME;
 780 }
 781
 782 static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
 783                                         struct transaction *t)
 784 {
 785         unsigned long tmp;
 786         int ret = 0;
 787
 788         if (t->rdata)
 789                 memset(t->rdata, 0, t->rlen);
 790
 791         /* start transaction */
 792         spin_lock_irqsave(&ec->lock, tmp);
 793         /* Enable GPE for command processing (IBF=0/OBF=1) */
 794         if (!acpi_ec_submit_flushable_request(ec)) {
 795                 ret = -EINVAL;
 796                 goto unlock;
 797         }
 798         ec_dbg_ref(ec, "Increase command");
 799         /* following two actions should be kept atomic */
 800         ec->curr = t;
 801         ec_dbg_req("Command(%s) started", acpi_ec_cmd_string(t->command));
 802         start_transaction(ec);
 803         spin_unlock_irqrestore(&ec->lock, tmp);
 804
 805         ret = ec_poll(ec);
 806
 807         spin_lock_irqsave(&ec->lock, tmp);
 808         if (t->irq_count == ec_storm_threshold)
 809                 acpi_ec_unmask_events(ec);
 810         ec_dbg_req("Command(%s) stopped", acpi_ec_cmd_string(t->command));
 811         ec->curr = NULL;
 812         /* Disable GPE for command processing (IBF=0/OBF=1) */
 813         acpi_ec_complete_request(ec);
 814         ec_dbg_ref(ec, "Decrease command");
 815 unlock:
 816         spin_unlock_irqrestore(&ec->lock, tmp);
 817         return ret;
 818 }
 819
 820 static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
 821 {
 822         int status;
 823         u32 glk;
 824
 825         if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
 826                 return -EINVAL;
 827
 828         mutex_lock(&ec->mutex);
 829         if (ec->global_lock) {
 830                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
 831                 if (ACPI_FAILURE(status)) {
 832                         status = -ENODEV;
 833                         goto unlock;
 834                 }
 835         }
 836
 837         status = acpi_ec_transaction_unlocked(ec, t);
 838
 839         if (ec->global_lock)
 840                 acpi_release_global_lock(glk);
 841 unlock:
 842         mutex_unlock(&ec->mutex);
 843         return status;
 844 }
 845
 846 static int acpi_ec_burst_enable(struct acpi_ec *ec)
 847 {
 848         u8 d;
 849         struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
 850                                 .wdata = NULL, .rdata = &d,
 851                                 .wlen = 0, .rlen = 1};
 852
 853         return acpi_ec_transaction_unlocked(ec, &t);
 854 }
 855
 856 static int acpi_ec_burst_disable(struct acpi_ec *ec)
 857 {
 858         struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
 859                                 .wdata = NULL, .rdata = NULL,
 860                                 .wlen = 0, .rlen = 0};
 861
 862         return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
 863                                 acpi_ec_transaction_unlocked(ec, &t) : 0;
 864 }
 865
 866 static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 *data)
 867 {
 868         int result;
 869         u8 d;
 870         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 871                                 .wdata = &address, .rdata = &d,
 872                                 .wlen = 1, .rlen = 1};
 873
 874         result = acpi_ec_transaction(ec, &t);
 875         *data = d;
 876         return result;
 877 }
 878
 879 static int acpi_ec_read_unlocked(struct acpi_ec *ec, u8 address, u8 *data)
 880 {
 881         int result;
 882         u8 d;
 883         struct transaction t = {.command = ACPI_EC_COMMAND_READ,
 884                                 .wdata = &address, .rdata = &d,
 885                                 .wlen = 1, .rlen = 1};
 886
 887         result = acpi_ec_transaction_unlocked(ec, &t);
 888         *data = d;
 889         return result;
 890 }
 891
 892 static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
 893 {
 894         u8 wdata[2] = { address, data };
 895         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 896                                 .wdata = wdata, .rdata = NULL,
 897                                 .wlen = 2, .rlen = 0};
 898
 899         return acpi_ec_transaction(ec, &t);
 900 }
 901
 902 static int acpi_ec_write_unlocked(struct acpi_ec *ec, u8 address, u8 data)
 903 {
 904         u8 wdata[2] = { address, data };
 905         struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
 906                                 .wdata = wdata, .rdata = NULL,
 907                                 .wlen = 2, .rlen = 0};
 908
 909         return acpi_ec_transaction_unlocked(ec, &t);
 910 }
 911
 912 int ec_read(u8 addr, u8 *val)
 913 {
 914         int err;
 915         u8 temp_data;
 916
 917         if (!first_ec)
 918                 return -ENODEV;
 919
 920         err = acpi_ec_read(first_ec, addr, &temp_data);
 921
 922         if (!err) {
 923                 *val = temp_data;
 924                 return 0;
 925         }
 926         return err;
 927 }
 928 EXPORT_SYMBOL(ec_read);
 929
 930 int ec_write(u8 addr, u8 val)
 931 {
 932         if (!first_ec)
 933                 return -ENODEV;
 934
 935         return acpi_ec_write(first_ec, addr, val);
 936 }
 937 EXPORT_SYMBOL(ec_write);
 938
 939 int ec_transaction(u8 command,
 940                    const u8 *wdata, unsigned wdata_len,
 941                    u8 *rdata, unsigned rdata_len)
 942 {
 943         struct transaction t = {.command = command,
 944                                 .wdata = wdata, .rdata = rdata,
 945                                 .wlen = wdata_len, .rlen = rdata_len};
 946
 947         if (!first_ec)
 948                 return -ENODEV;
 949
 950         return acpi_ec_transaction(first_ec, &t);
 951 }
 952 EXPORT_SYMBOL(ec_transaction);
 953
 954 /* Get the handle to the EC device */
 955 acpi_handle ec_get_handle(void)
 956 {
 957         if (!first_ec)
 958                 return NULL;
 959         return first_ec->handle;
 960 }
 961 EXPORT_SYMBOL(ec_get_handle);
 962
 963 static void acpi_ec_start(struct acpi_ec *ec, bool resuming)
 964 {
 965         unsigned long flags;
 966
 967         spin_lock_irqsave(&ec->lock, flags);
 968         if (!test_and_set_bit(EC_FLAGS_STARTED, &ec->flags)) {
 969                 ec_dbg_drv("Starting EC");
 970                 /* Enable GPE for event processing (SCI_EVT=1) */
 971                 if (!resuming) {
 972                         acpi_ec_submit_request(ec);
 973                         ec_dbg_ref(ec, "Increase driver");
 974                 }
 975                 ec_log_drv("EC started");
 976         }
 977         spin_unlock_irqrestore(&ec->lock, flags);
 978 }
 979
 980 static bool acpi_ec_stopped(struct acpi_ec *ec)
 981 {
 982         unsigned long flags;
 983         bool flushed;
 984
 985         spin_lock_irqsave(&ec->lock, flags);
 986         flushed = acpi_ec_flushed(ec);
 987         spin_unlock_irqrestore(&ec->lock, flags);
 988         return flushed;
 989 }
 990
 991 static void acpi_ec_stop(struct acpi_ec *ec, bool suspending)
 992 {
 993         unsigned long flags;
 994
 995         spin_lock_irqsave(&ec->lock, flags);
 996         if (acpi_ec_started(ec)) {
 997                 ec_dbg_drv("Stopping EC");
 998                 set_bit(EC_FLAGS_STOPPED, &ec->flags);
 999                 spin_unlock_irqrestore(&ec->lock, flags);
1000                 wait_event(ec->wait, acpi_ec_stopped(ec));
1001                 spin_lock_irqsave(&ec->lock, flags);
1002                 /* Disable GPE for event processing (SCI_EVT=1) */
1003                 if (!suspending) {
1004                         acpi_ec_complete_request(ec);
1005                         ec_dbg_ref(ec, "Decrease driver");
1006                 } else if (!ec_freeze_events)
1007                         __acpi_ec_disable_event(ec);
1008                 clear_bit(EC_FLAGS_STARTED, &ec->flags);
1009                 clear_bit(EC_FLAGS_STOPPED, &ec->flags);
1010                 ec_log_drv("EC stopped");
1011         }
1012         spin_unlock_irqrestore(&ec->lock, flags);
1013 }
1014
1015 static void acpi_ec_enter_noirq(struct acpi_ec *ec)
1016 {
1017         unsigned long flags;
1018
1019         spin_lock_irqsave(&ec->lock, flags);
1020         ec->busy_polling = true;
1021         ec->polling_guard = 0;
1022         ec_log_drv("interrupt blocked");
1023         spin_unlock_irqrestore(&ec->lock, flags);
1024 }
1025
1026 static void acpi_ec_leave_noirq(struct acpi_ec *ec)
1027 {
1028         unsigned long flags;
1029
1030         spin_lock_irqsave(&ec->lock, flags);
1031         ec->busy_polling = ec_busy_polling;
1032         ec->polling_guard = ec_polling_guard;
1033         ec_log_drv("interrupt unblocked");
1034         spin_unlock_irqrestore(&ec->lock, flags);
1035 }
1036
1037 void acpi_ec_block_transactions(void)
1038 {
1039         struct acpi_ec *ec = first_ec;
1040
1041         if (!ec)
1042                 return;
1043
1044         mutex_lock(&ec->mutex);
1045         /* Prevent transactions from being carried out */
1046         acpi_ec_stop(ec, true);
1047         mutex_unlock(&ec->mutex);
1048 }
1049
1050 void acpi_ec_unblock_transactions(void)
1051 {
1052         /*
1053          * Allow transactions to happen again (this function is called from
1054          * atomic context during wakeup, so we don't need to acquire the mutex).
1055          */
1056         if (first_ec)
1057                 acpi_ec_start(first_ec, true);
1058 }
1059
1060 /* --------------------------------------------------------------------------
1061                                 Event Management
1062    -------------------------------------------------------------------------- */
1063 static struct acpi_ec_query_handler *
1064 acpi_ec_get_query_handler_by_value(struct acpi_ec *ec, u8 value)
1065 {
1066         struct acpi_ec_query_handler *handler;
1067
1068         mutex_lock(&ec->mutex);
1069         list_for_each_entry(handler, &ec->list, node) {
1070                 if (value == handler->query_bit) {
1071                         kref_get(&handler->kref);
1072                         mutex_unlock(&ec->mutex);
1073                         return handler;
1074                 }
1075         }
1076         mutex_unlock(&ec->mutex);
1077         return NULL;
1078 }
1079
1080 static void acpi_ec_query_handler_release(struct kref *kref)
1081 {
1082         struct acpi_ec_query_handler *handler =
1083                 container_of(kref, struct acpi_ec_query_handler, kref);
1084
1085         kfree(handler);
1086 }
1087
1088 static void acpi_ec_put_query_handler(struct acpi_ec_query_handler *handler)
1089 {
1090         kref_put(&handler->kref, acpi_ec_query_handler_release);
1091 }
1092
1093 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
1094                               acpi_handle handle, acpi_ec_query_func func,
1095                               void *data)
1096 {
1097         struct acpi_ec_query_handler *handler;
1098
1099         if (!handle && !func)
1100                 return -EINVAL;
1101
1102         handler = kzalloc(sizeof(*handler), GFP_KERNEL);
1103         if (!handler)
1104                 return -ENOMEM;
1105
1106         handler->query_bit = query_bit;
1107         handler->handle = handle;
1108         handler->func = func;
1109         handler->data = data;
1110         mutex_lock(&ec->mutex);
1111         kref_init(&handler->kref);
1112         list_add(&handler->node, &ec->list);
1113         mutex_unlock(&ec->mutex);
1114
1115         return 0;
1116 }
1117 EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);
1118
1119 static void acpi_ec_remove_query_handlers(struct acpi_ec *ec,
1120                                           bool remove_all, u8 query_bit)
1121 {
1122         struct acpi_ec_query_handler *handler, *tmp;
1123         LIST_HEAD(free_list);
1124
1125         mutex_lock(&ec->mutex);
1126         list_for_each_entry_safe(handler, tmp, &ec->list, node) {
1127                 /*
1128                  * When remove_all is false, only remove custom query handlers
1129                  * which have handler->func set. This is done to preserve query
1130                  * handlers discovered thru ACPI, as they should continue handling
1131                  * EC queries.
1132                  */
1133                 if (remove_all || (handler->func && handler->query_bit == query_bit)) {
1134                         list_del_init(&handler->node);
1135                         list_add(&handler->node, &free_list);
1136
1137                 }
1138         }
1139         mutex_unlock(&ec->mutex);
1140         list_for_each_entry_safe(handler, tmp, &free_list, node)
1141                 acpi_ec_put_query_handler(handler);
1142 }
1143
1144 void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
1145 {
1146         acpi_ec_remove_query_handlers(ec, false, query_bit);
1147         flush_workqueue(ec_query_wq);
1148 }
1149 EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);
1150
1151 static void acpi_ec_event_processor(struct work_struct *work)
1152 {
1153         struct acpi_ec_query *q = container_of(work, struct acpi_ec_query, work);
1154         struct acpi_ec_query_handler *handler = q->handler;
1155         struct acpi_ec *ec = q->ec;
1156
1157         ec_dbg_evt("Query(0x%02x) started", handler->query_bit);
1158
1159         if (handler->func)
1160                 handler->func(handler->data);
1161         else if (handler->handle)
1162                 acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
1163
1164         ec_dbg_evt("Query(0x%02x) stopped", handler->query_bit);
1165
1166         spin_lock_irq(&ec->lock);
1167         ec->queries_in_progress--;
1168         spin_unlock_irq(&ec->lock);
1169
1170         acpi_ec_put_query_handler(handler);
1171         kfree(q);
1172 }
1173
1174 static struct acpi_ec_query *acpi_ec_create_query(struct acpi_ec *ec, u8 *pval)
1175 {
1176         struct acpi_ec_query *q;
1177         struct transaction *t;
1178
1179         q = kzalloc(sizeof (struct acpi_ec_query), GFP_KERNEL);
1180         if (!q)
1181                 return NULL;
1182
1183         INIT_WORK(&q->work, acpi_ec_event_processor);
1184         t = &q->transaction;
1185         t->command = ACPI_EC_COMMAND_QUERY;
1186         t->rdata = pval;
1187         t->rlen = 1;
1188         q->ec = ec;
1189         return q;
1190 }
1191
1192 static int acpi_ec_submit_query(struct acpi_ec *ec)
1193 {
1194         struct acpi_ec_query *q;
1195         u8 value = 0;
1196         int result;
1197
1198         q = acpi_ec_create_query(ec, &value);
1199         if (!q)
1200                 return -ENOMEM;
1201
1202         /*
1203          * Query the EC to find out which _Qxx method we need to evaluate.
1204          * Note that successful completion of the query causes the ACPI_EC_SCI
1205          * bit to be cleared (and thus clearing the interrupt source).
1206          */
1207         result = acpi_ec_transaction(ec, &q->transaction);
1208         if (result)
1209                 goto err_exit;
1210
1211         if (!value) {
1212                 result = -ENODATA;
1213                 goto err_exit;
1214         }
1215
1216         q->handler = acpi_ec_get_query_handler_by_value(ec, value);
1217         if (!q->handler) {
1218                 result = -ENODATA;
1219                 goto err_exit;
1220         }
1221
1222         /*
1223          * It is reported that _Qxx are evaluated in a parallel way on Windows:
1224          * https://bugzilla.kernel.org/show_bug.cgi?id=94411
1225          *
1226          * Put this log entry before queue_work() to make it appear in the log
1227          * before any other messages emitted during workqueue handling.
1228          */
1229         ec_dbg_evt("Query(0x%02x) scheduled", value);
1230
1231         spin_lock_irq(&ec->lock);
1232
1233         ec->queries_in_progress++;
1234         queue_work(ec_query_wq, &q->work);
1235
1236         spin_unlock_irq(&ec->lock);
1237
1238         return 0;
1239
1240 err_exit:
1241         kfree(q);
1242
1243         return result;
1244 }
1245
1246 static void acpi_ec_event_handler(struct work_struct *work)
1247 {
1248         struct acpi_ec *ec = container_of(work, struct acpi_ec, work);
1249
1250         ec_dbg_evt("Event started");
1251
1252         spin_lock_irq(&ec->lock);
1253
1254         while (ec->events_to_process) {
1255                 spin_unlock_irq(&ec->lock);
1256
1257                 acpi_ec_submit_query(ec);
1258
1259                 spin_lock_irq(&ec->lock);
1260
1261                 ec->events_to_process--;
1262         }
1263
1264         /*
1265          * Before exit, make sure that the it will be possible to queue up the
1266          * event handling work again regardless of whether or not the query
1267          * queued up above is processed successfully.
1268          */
1269         if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT) {
1270                 bool guard_timeout;
1271
1272                 acpi_ec_complete_event(ec);
1273
1274                 ec_dbg_evt("Event stopped");
1275
1276                 spin_unlock_irq(&ec->lock);
1277
1278                 guard_timeout = !!ec_guard(ec);
1279
1280                 spin_lock_irq(&ec->lock);
1281
1282                 /* Take care of SCI_EVT unless someone else is doing that. */
1283                 if (guard_timeout && !ec->curr)
1284                         advance_transaction(ec, false);
1285         } else {
1286                 acpi_ec_close_event(ec);
1287
1288                 ec_dbg_evt("Event stopped");
1289         }
1290
1291         ec->events_in_progress--;
1292
1293         spin_unlock_irq(&ec->lock);
1294 }
1295
1296 static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)
1297 {
1298         /*
1299          * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1
1300          * changes to always trigger a GPE interrupt.
1301          *
1302          * GPE STS is a W1C register, which means:
1303          *
1304          * 1. Software can clear it without worrying about clearing the other
1305          *    GPEs' STS bits when the hardware sets them in parallel.
1306          *
1307          * 2. As long as software can ensure only clearing it when it is set,
1308          *    hardware won't set it in parallel.
1309          */
1310         if (ec->gpe >= 0 && acpi_ec_gpe_status_set(ec))
1311                 acpi_clear_gpe(NULL, ec->gpe);
1312
1313         advance_transaction(ec, true);
1314 }
1315
1316 static void acpi_ec_handle_interrupt(struct acpi_ec *ec)
1317 {
1318         unsigned long flags;
1319
1320         spin_lock_irqsave(&ec->lock, flags);
1321
1322         clear_gpe_and_advance_transaction(ec, true);
1323
1324         spin_unlock_irqrestore(&ec->lock, flags);
1325 }
1326
1327 static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
1328                                u32 gpe_number, void *data)
1329 {
1330         acpi_ec_handle_interrupt(data);
1331         return ACPI_INTERRUPT_HANDLED;
1332 }
1333
1334 static irqreturn_t acpi_ec_irq_handler(int irq, void *data)
1335 {
1336         acpi_ec_handle_interrupt(data);
1337         return IRQ_HANDLED;
1338 }
1339
1340 /* --------------------------------------------------------------------------
1341  *                           Address Space Management
1342  * -------------------------------------------------------------------------- */
1343
1344 static acpi_status
1345 acpi_ec_space_handler(u32 function, acpi_physical_address address,
1346                       u32 bits, u64 *value64,
1347                       void *handler_context, void *region_context)
1348 {
1349         struct acpi_ec *ec = handler_context;
1350         int result = 0, i, bytes = bits / 8;
1351         u8 *value = (u8 *)value64;
1352         u32 glk;
1353
1354         if ((address > 0xFF) || !value || !handler_context)
1355                 return AE_BAD_PARAMETER;
1356
1357         if (function != ACPI_READ && function != ACPI_WRITE)
1358                 return AE_BAD_PARAMETER;
1359
1360         mutex_lock(&ec->mutex);
1361
1362         if (ec->global_lock) {
1363                 acpi_status status;
1364
1365                 status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
1366                 if (ACPI_FAILURE(status)) {
1367                         result = -ENODEV;
1368                         goto unlock;
1369                 }
1370         }
1371
1372         if (ec->busy_polling || bits > 8)
1373                 acpi_ec_burst_enable(ec);
1374
1375         for (i = 0; i < bytes; ++i, ++address, ++value) {
1376                 result = (function == ACPI_READ) ?
1377                         acpi_ec_read_unlocked(ec, address, value) :
1378                         acpi_ec_write_unlocked(ec, address, *value);
1379                 if (result < 0)
1380                         break;
1381         }
1382
1383         if (ec->busy_polling || bits > 8)
1384                 acpi_ec_burst_disable(ec);
1385
1386         if (ec->global_lock)
1387                 acpi_release_global_lock(glk);
1388
1389 unlock:
1390         mutex_unlock(&ec->mutex);
1391
1392         switch (result) {
1393         case -EINVAL:
1394                 return AE_BAD_PARAMETER;
1395         case -ENODEV:
1396                 return AE_NOT_FOUND;
1397         case -ETIME:
1398                 return AE_TIME;
1399         case 0:
1400                 return AE_OK;
1401         default:
1402                 return AE_ERROR;
1403         }
1404 }
1405
1406 /* --------------------------------------------------------------------------
1407  *                             Driver Interface
1408  * -------------------------------------------------------------------------- */
1409
1410 static acpi_status
1411 ec_parse_io_ports(struct acpi_resource *resource, void *context);
1412
1413 static void acpi_ec_free(struct acpi_ec *ec)
1414 {
1415         if (first_ec == ec)
1416                 first_ec = NULL;
1417         if (boot_ec == ec)
1418                 boot_ec = NULL;
1419         kfree(ec);
1420 }
1421
1422 static struct acpi_ec *acpi_ec_alloc(void)
1423 {
1424         struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
1425
1426         if (!ec)
1427                 return NULL;
1428         mutex_init(&ec->mutex);
1429         init_waitqueue_head(&ec->wait);
1430         INIT_LIST_HEAD(&ec->list);
1431         spin_lock_init(&ec->lock);
1432         INIT_WORK(&ec->work, acpi_ec_event_handler);
1433         ec->timestamp = jiffies;
1434         ec->busy_polling = true;
1435         ec->polling_guard = 0;
1436         ec->gpe = -1;
1437         ec->irq = -1;
1438         return ec;
1439 }
1440
1441 static acpi_status
1442 acpi_ec_register_query_methods(acpi_handle handle, u32 level,
1443                                void *context, void **return_value)
1444 {
1445         char node_name[5];
1446         struct acpi_buffer buffer = { sizeof(node_name), node_name };
1447         struct acpi_ec *ec = context;
1448         int value = 0;
1449         acpi_status status;
1450
1451         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
1452
1453         if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1)
1454                 acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
1455         return AE_OK;
1456 }
1457
1458 static acpi_status
1459 ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
1460 {
1461         acpi_status status;
1462         unsigned long long tmp = 0;
1463         struct acpi_ec *ec = context;
1464
1465         /* clear addr values, ec_parse_io_ports depend on it */
1466         ec->command_addr = ec->data_addr = 0;
1467
1468         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
1469                                      ec_parse_io_ports, ec);
1470         if (ACPI_FAILURE(status))
1471                 return status;
1472         if (ec->data_addr == 0 || ec->command_addr == 0)
1473                 return AE_OK;
1474
1475         /* Get GPE bit assignment (EC events). */
1476         /* TODO: Add support for _GPE returning a package */
1477         status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
1478         if (ACPI_SUCCESS(status))
1479                 ec->gpe = tmp;
1480         /*
1481          * Errors are non-fatal, allowing for ACPI Reduced Hardware
1482          * platforms which use GpioInt instead of GPE.
1483          */
1484
1485         /* Use the global lock for all EC transactions? */
1486         tmp = 0;
1487         acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
1488         ec->global_lock = tmp;
1489         ec->handle = handle;
1490         return AE_CTRL_TERMINATE;
1491 }
1492
1493 static bool install_gpe_event_handler(struct acpi_ec *ec)
1494 {
1495         acpi_status status;
1496
1497         status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
1498                                               ACPI_GPE_EDGE_TRIGGERED,
1499                                               &acpi_ec_gpe_handler, ec);
1500         if (ACPI_FAILURE(status))
1501                 return false;
1502
1503         if (test_bit(EC_FLAGS_STARTED, &ec->flags) && ec->reference_count >= 1)
1504                 acpi_ec_enable_gpe(ec, true);
1505
1506         return true;
1507 }
1508
1509 static bool install_gpio_irq_event_handler(struct acpi_ec *ec)
1510 {
1511         return request_threaded_irq(ec->irq, NULL, acpi_ec_irq_handler,
1512                                     IRQF_SHARED | IRQF_ONESHOT, "ACPI EC", ec) >= 0;
1513 }
1514
1515 /**
1516  * ec_install_handlers - Install service callbacks and register query methods.
1517  * @ec: Target EC.
1518  * @device: ACPI device object corresponding to @ec.
1519  * @call_reg: If _REG should be called to notify OpRegion availability
1520  *
1521  * Install a handler for the EC address space type unless it has been installed
1522  * already.  If @device is not NULL, also look for EC query methods in the
1523  * namespace and register them, and install an event (either GPE or GPIO IRQ)
1524  * handler for the EC, if possible.
1525  *
1526  * Return:
1527  * -ENODEV if the address space handler cannot be installed, which means
1528  *  "unable to handle transactions",
1529  * -EPROBE_DEFER if GPIO IRQ acquisition needs to be deferred,
1530  * or 0 (success) otherwise.
1531  */
1532 static int ec_install_handlers(struct acpi_ec *ec, struct acpi_device *device,
1533                                bool call_reg)
1534 {
1535         acpi_status status;
1536
1537         acpi_ec_start(ec, false);
1538
1539         if (!test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1540                 acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1541
1542                 acpi_ec_enter_noirq(ec);
1543                 status = acpi_install_address_space_handler_no_reg(scope_handle,
1544                                                                    ACPI_ADR_SPACE_EC,
1545                                                                    &acpi_ec_space_handler,
1546                                                                    NULL, ec);
1547                 if (ACPI_FAILURE(status)) {
1548                         acpi_ec_stop(ec, false);
1549                         return -ENODEV;
1550                 }
1551                 set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1552         }
1553
1554         if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
1555                 acpi_execute_reg_methods(ec->handle, ACPI_UINT32_MAX, ACPI_ADR_SPACE_EC);
1556                 set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
1557         }
1558
1559         if (!device)
1560                 return 0;
1561
1562         if (ec->gpe < 0) {
1563                 /* ACPI reduced hardware platforms use a GpioInt from _CRS. */
1564                 int irq = acpi_dev_gpio_irq_get(device, 0);
1565                 /*
1566                  * Bail out right away for deferred probing or complete the
1567                  * initialization regardless of any other errors.
1568                  */
1569                 if (irq == -EPROBE_DEFER)
1570                         return -EPROBE_DEFER;
1571                 else if (irq >= 0)
1572                         ec->irq = irq;
1573         }
1574
1575         if (!test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1576                 /* Find and register all query methods */
1577                 acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
1578                                     acpi_ec_register_query_methods,
1579                                     NULL, ec, NULL);
1580                 set_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1581         }
1582         if (!test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1583                 bool ready = false;
1584
1585                 if (ec->gpe >= 0)
1586                         ready = install_gpe_event_handler(ec);
1587                 else if (ec->irq >= 0)
1588                         ready = install_gpio_irq_event_handler(ec);
1589
1590                 if (ready) {
1591                         set_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1592                         acpi_ec_leave_noirq(ec);
1593                 }
1594                 /*
1595                  * Failures to install an event handler are not fatal, because
1596                  * the EC can be polled for events.
1597                  */
1598         }
1599         /* EC is fully operational, allow queries */
1600         acpi_ec_enable_event(ec);
1601
1602         return 0;
1603 }
1604
1605 static void ec_remove_handlers(struct acpi_ec *ec)
1606 {
1607         acpi_handle scope_handle = ec == first_ec ? ACPI_ROOT_OBJECT : ec->handle;
1608
1609         if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
1610                 if (ACPI_FAILURE(acpi_remove_address_space_handler(
1611                                                 scope_handle,
1612                                                 ACPI_ADR_SPACE_EC,
1613                                                 &acpi_ec_space_handler)))
1614                         pr_err("failed to remove space handler\n");
1615                 clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
1616         }
1617
1618         /*
1619          * Stops handling the EC transactions after removing the operation
1620          * region handler. This is required because _REG(DISCONNECT)
1621          * invoked during the removal can result in new EC transactions.
1622          *
1623          * Flushes the EC requests and thus disables the GPE before
1624          * removing the GPE handler. This is required by the current ACPICA
1625          * GPE core. ACPICA GPE core will automatically disable a GPE when
1626          * it is indicated but there is no way to handle it. So the drivers
1627          * must disable the GPEs prior to removing the GPE handlers.
1628          */
1629         acpi_ec_stop(ec, false);
1630
1631         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1632                 if (ec->gpe >= 0 &&
1633                     ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
1634                                  &acpi_ec_gpe_handler)))
1635                         pr_err("failed to remove gpe handler\n");
1636
1637                 if (ec->irq >= 0)
1638                         free_irq(ec->irq, ec);
1639
1640                 clear_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags);
1641         }
1642         if (test_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags)) {
1643                 acpi_ec_remove_query_handlers(ec, true, 0);
1644                 clear_bit(EC_FLAGS_QUERY_METHODS_INSTALLED, &ec->flags);
1645         }
1646 }
1647
1648 static int acpi_ec_setup(struct acpi_ec *ec, struct acpi_device *device, bool call_reg)
1649 {
1650         int ret;
1651
1652         /* First EC capable of handling transactions */
1653         if (!first_ec)
1654                 first_ec = ec;
1655
1656         ret = ec_install_handlers(ec, device, call_reg);
1657         if (ret) {
1658                 if (ec == first_ec)
1659                         first_ec = NULL;
1660
1661                 return ret;
1662         }
1663
1664         pr_info("EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n", ec->command_addr,
1665                 ec->data_addr);
1666
1667         if (test_bit(EC_FLAGS_EVENT_HANDLER_INSTALLED, &ec->flags)) {
1668                 if (ec->gpe >= 0)
1669                         pr_info("GPE=0x%x\n", ec->gpe);
1670                 else
1671                         pr_info("IRQ=%d\n", ec->irq);
1672         }
1673
1674         return ret;
1675 }
1676
1677 static int acpi_ec_add(struct acpi_device *device)
1678 {
1679         struct acpi_ec *ec;
1680         int ret;
1681
1682         strscpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
1683         strscpy(acpi_device_class(device), ACPI_EC_CLASS);
1684
1685         if (boot_ec && (boot_ec->handle == device->handle ||
1686             !strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
1687                 /* Fast path: this device corresponds to the boot EC. */
1688                 ec = boot_ec;
1689         } else {
1690                 acpi_status status;
1691
1692                 ec = acpi_ec_alloc();
1693                 if (!ec)
1694                         return -ENOMEM;
1695
1696                 status = ec_parse_device(device->handle, 0, ec, NULL);
1697                 if (status != AE_CTRL_TERMINATE) {
1698                         ret = -EINVAL;
1699                         goto err;
1700                 }
1701
1702                 if (boot_ec && ec->command_addr == boot_ec->command_addr &&
1703                     ec->data_addr == boot_ec->data_addr) {
1704                         /*
1705                          * Trust PNP0C09 namespace location rather than ECDT ID.
1706                          * But trust ECDT GPE rather than _GPE because of ASUS
1707                          * quirks. So do not change boot_ec->gpe to ec->gpe,
1708                          * except when the TRUST_DSDT_GPE quirk is set.
1709                          */
1710                         boot_ec->handle = ec->handle;
1711
1712                         if (EC_FLAGS_TRUST_DSDT_GPE)
1713                                 boot_ec->gpe = ec->gpe;
1714
1715                         acpi_handle_debug(ec->handle, "duplicated.\n");
1716                         acpi_ec_free(ec);
1717                         ec = boot_ec;
1718                 }
1719         }
1720
1721         ret = acpi_ec_setup(ec, device, true);
1722         if (ret)
1723                 goto err;
1724
1725         if (ec == boot_ec)
1726                 acpi_handle_info(boot_ec->handle,
1727                                  "Boot %s EC initialization complete\n",
1728                                  boot_ec_is_ecdt ? "ECDT" : "DSDT");
1729
1730         acpi_handle_info(ec->handle,
1731                          "EC: Used to handle transactions and events\n");
1732
1733         device->driver_data = ec;
1734
1735         ret = !!request_region(ec->data_addr, 1, "EC data");
1736         WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
1737         ret = !!request_region(ec->command_addr, 1, "EC cmd");
1738         WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
1739
1740         /* Reprobe devices depending on the EC */
1741         acpi_dev_clear_dependencies(device);
1742
1743         acpi_handle_debug(ec->handle, "enumerated.\n");
1744         return 0;
1745
1746 err:
1747         if (ec != boot_ec)
1748                 acpi_ec_free(ec);
1749
1750         return ret;
1751 }
1752
1753 static void acpi_ec_remove(struct acpi_device *device)
1754 {
1755         struct acpi_ec *ec;
1756
1757         if (!device)
1758                 return;
1759
1760         ec = acpi_driver_data(device);
1761         release_region(ec->data_addr, 1);
1762         release_region(ec->command_addr, 1);
1763         device->driver_data = NULL;
1764         if (ec != boot_ec) {
1765                 ec_remove_handlers(ec);
1766                 acpi_ec_free(ec);
1767         }
1768 }
1769
1770 void acpi_ec_register_opregions(struct acpi_device *adev)
1771 {
1772         if (first_ec && first_ec->handle != adev->handle)
1773                 acpi_execute_reg_methods(adev->handle, 1, ACPI_ADR_SPACE_EC);
1774 }
1775
1776 static acpi_status
1777 ec_parse_io_ports(struct acpi_resource *resource, void *context)
1778 {
1779         struct acpi_ec *ec = context;
1780
1781         if (resource->type != ACPI_RESOURCE_TYPE_IO)
1782                 return AE_OK;
1783
1784         /*
1785          * The first address region returned is the data port, and
1786          * the second address region returned is the status/command
1787          * port.
1788          */
1789         if (ec->data_addr == 0)
1790                 ec->data_addr = resource->data.io.minimum;
1791         else if (ec->command_addr == 0)
1792                 ec->command_addr = resource->data.io.minimum;
1793         else
1794                 return AE_CTRL_TERMINATE;
1795
1796         return AE_OK;
1797 }
1798
1799 static const struct acpi_device_id ec_device_ids[] = {
1800         {"PNP0C09", 0},
1801         {ACPI_ECDT_HID, 0},
1802         {"", 0},
1803 };
1804
1805 /*
1806  * This function is not Windows-compatible as Windows never enumerates the
1807  * namespace EC before the main ACPI device enumeration process. It is
1808  * retained for historical reason and will be deprecated in the future.
1809  */
1810 void __init acpi_ec_dsdt_probe(void)
1811 {
1812         struct acpi_ec *ec;
1813         acpi_status status;
1814         int ret;
1815
1816         /*
1817          * If a platform has ECDT, there is no need to proceed as the
1818          * following probe is not a part of the ACPI device enumeration,
1819          * executing _STA is not safe, and thus this probe may risk of
1820          * picking up an invalid EC device.
1821          */
1822         if (boot_ec)
1823                 return;
1824
1825         ec = acpi_ec_alloc();
1826         if (!ec)
1827                 return;
1828
1829         /*
1830          * At this point, the namespace is initialized, so start to find
1831          * the namespace objects.
1832          */
1833         status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device, ec, NULL);
1834         if (ACPI_FAILURE(status) || !ec->handle) {
1835                 acpi_ec_free(ec);
1836                 return;
1837         }
1838
1839         /*
1840          * When the DSDT EC is available, always re-configure boot EC to
1841          * have _REG evaluated. _REG can only be evaluated after the
1842          * namespace initialization.
1843          * At this point, the GPE is not fully initialized, so do not to
1844          * handle the events.
1845          */
1846         ret = acpi_ec_setup(ec, NULL, true);
1847         if (ret) {
1848                 acpi_ec_free(ec);
1849                 return;
1850         }
1851
1852         boot_ec = ec;
1853
1854         acpi_handle_info(ec->handle,
1855                          "Boot DSDT EC used to handle transactions\n");
1856 }
1857
1858 /*
1859  * acpi_ec_ecdt_start - Finalize the boot ECDT EC initialization.
1860  *
1861  * First, look for an ACPI handle for the boot ECDT EC if acpi_ec_add() has not
1862  * found a matching object in the namespace.
1863  *
1864  * Next, in case the DSDT EC is not functioning, it is still necessary to
1865  * provide a functional ECDT EC to handle events, so add an extra device object
1866  * to represent it (see https://bugzilla.kernel.org/show_bug.cgi?id=115021).
1867  *
1868  * This is useful on platforms with valid ECDT and invalid DSDT EC settings,
1869  * like ASUS X550ZE (see https://bugzilla.kernel.org/show_bug.cgi?id=196847).
1870  */
1871 static void __init acpi_ec_ecdt_start(void)
1872 {
1873         struct acpi_table_ecdt *ecdt_ptr;
1874         acpi_handle handle;
1875         acpi_status status;
1876
1877         /* Bail out if a matching EC has been found in the namespace. */
1878         if (!boot_ec || boot_ec->handle != ACPI_ROOT_OBJECT)
1879                 return;
1880
1881         /* Look up the object pointed to from the ECDT in the namespace. */
1882         status = acpi_get_table(ACPI_SIG_ECDT, 1,
1883                                 (struct acpi_table_header **)&ecdt_ptr);
1884         if (ACPI_FAILURE(status))
1885                 return;
1886
1887         status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
1888         if (ACPI_SUCCESS(status)) {
1889                 boot_ec->handle = handle;
1890
1891                 /* Add a special ACPI device object to represent the boot EC. */
1892                 acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
1893         }
1894
1895         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
1896 }
1897
1898 /*
1899  * On some hardware it is necessary to clear events accumulated by the EC during
1900  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
1901  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
1902  *
1903  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
1904  *
1905  * Ideally, the EC should also be instructed NOT to accumulate events during
1906  * sleep (which Windows seems to do somehow), but the interface to control this
1907  * behaviour is not known at this time.
1908  *
1909  * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
1910  * however it is very likely that other Samsung models are affected.
1911  *
1912  * On systems which don't accumulate _Q events during sleep, this extra check
1913  * should be harmless.
1914  */
1915 static int ec_clear_on_resume(const struct dmi_system_id *id)
1916 {
1917         pr_debug("Detected system needing EC poll on resume.\n");
1918         EC_FLAGS_CLEAR_ON_RESUME = 1;
1919         ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
1920         return 0;
1921 }
1922
1923 /*
1924  * Some ECDTs contain wrong register addresses.
1925  * MSI MS-171F
1926  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1927  */
1928 static int ec_correct_ecdt(const struct dmi_system_id *id)
1929 {
1930         pr_debug("Detected system needing ECDT address correction.\n");
1931         EC_FLAGS_CORRECT_ECDT = 1;
1932         return 0;
1933 }
1934
1935 /*
1936  * Some ECDTs contain wrong GPE setting, but they share the same port addresses
1937  * with DSDT EC, don't duplicate the DSDT EC with ECDT EC in this case.
1938  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1939  */
1940 static int ec_honor_dsdt_gpe(const struct dmi_system_id *id)
1941 {
1942         pr_debug("Detected system needing DSDT GPE setting.\n");
1943         EC_FLAGS_TRUST_DSDT_GPE = 1;
1944         return 0;
1945 }
1946
1947 static const struct dmi_system_id ec_dmi_table[] __initconst = {
1948         {
1949                 /*
1950                  * MSI MS-171F
1951                  * https://bugzilla.kernel.org/show_bug.cgi?id=12461
1952                  */
1953                 .callback = ec_correct_ecdt,
1954                 .matches = {
1955                         DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star"),
1956                         DMI_MATCH(DMI_PRODUCT_NAME, "MS-171F"),
1957                 },
1958         },
1959         {
1960                 /*
1961                  * HP Pavilion Gaming Laptop 15-cx0xxx
1962                  * https://bugzilla.kernel.org/show_bug.cgi?id=209989
1963                  */
1964                 .callback = ec_honor_dsdt_gpe,
1965                 .matches = {
1966                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1967                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-cx0xxx"),
1968                 },
1969         },
1970         {
1971                 /*
1972                  * HP Pavilion Gaming Laptop 15-cx0041ur
1973                  */
1974                 .callback = ec_honor_dsdt_gpe,
1975                 .matches = {
1976                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1977                         DMI_MATCH(DMI_PRODUCT_NAME, "HP 15-cx0041ur"),
1978                 },
1979         },
1980         {
1981                 /*
1982                  * HP Pavilion Gaming Laptop 15-dk1xxx
1983                  * https://github.com/systemd/systemd/issues/28942
1984                  */
1985                 .callback = ec_honor_dsdt_gpe,
1986                 .matches = {
1987                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1988                         DMI_MATCH(DMI_PRODUCT_NAME, "HP Pavilion Gaming Laptop 15-dk1xxx"),
1989                 },
1990         },
1991         {
1992                 /*
1993                  * HP 250 G7 Notebook PC
1994                  */
1995                 .callback = ec_honor_dsdt_gpe,
1996                 .matches = {
1997                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
1998                         DMI_MATCH(DMI_PRODUCT_NAME, "HP 250 G7 Notebook PC"),
1999                 },
2000         },
2001         {
2002                 /*
2003                  * Samsung hardware
2004                  * https://bugzilla.kernel.org/show_bug.cgi?id=44161
2005                  */
2006                 .callback = ec_clear_on_resume,
2007                 .matches = {
2008                         DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD."),
2009                 },
2010         },
2011         {}
2012 };
2013
2014 void __init acpi_ec_ecdt_probe(void)
2015 {
2016         struct acpi_table_ecdt *ecdt_ptr;
2017         struct acpi_ec *ec;
2018         acpi_status status;
2019         int ret;
2020
2021         /* Generate a boot ec context. */
2022         dmi_check_system(ec_dmi_table);
2023         status = acpi_get_table(ACPI_SIG_ECDT, 1,
2024                                 (struct acpi_table_header **)&ecdt_ptr);
2025         if (ACPI_FAILURE(status))
2026                 return;
2027
2028         if (!ecdt_ptr->control.address || !ecdt_ptr->data.address) {
2029                 /*
2030                  * Asus X50GL:
2031                  * https://bugzilla.kernel.org/show_bug.cgi?id=11880
2032                  */
2033                 goto out;
2034         }
2035
2036         if (!strstarts(ecdt_ptr->id, "\\")) {
2037                 /*
2038                  * The ECDT table on some MSI notebooks contains invalid data, together
2039                  * with an empty ID string ("").
2040                  *
2041                  * Section 5.2.15 of the ACPI specification requires the ID string to be
2042                  * a "fully qualified reference to the (...) embedded controller device",
2043                  * so this string always has to start with a backslash.
2044                  *
2045                  * By verifying this we can avoid such faulty ECDT tables in a safe way.
2046                  */
2047                 pr_err(FW_BUG "Ignoring ECDT due to invalid ID string \"%s\"\n", ecdt_ptr->id);
2048                 goto out;
2049         }
2050
2051         ec = acpi_ec_alloc();
2052         if (!ec)
2053                 goto out;
2054
2055         if (EC_FLAGS_CORRECT_ECDT) {
2056                 ec->command_addr = ecdt_ptr->data.address;
2057                 ec->data_addr = ecdt_ptr->control.address;
2058         } else {
2059                 ec->command_addr = ecdt_ptr->control.address;
2060                 ec->data_addr = ecdt_ptr->data.address;
2061         }
2062
2063         /*
2064          * Ignore the GPE value on Reduced Hardware platforms.
2065          * Some products have this set to an erroneous value.
2066          */
2067         if (!acpi_gbl_reduced_hardware)
2068                 ec->gpe = ecdt_ptr->gpe;
2069
2070         ec->handle = ACPI_ROOT_OBJECT;
2071
2072         /*
2073          * At this point, the namespace is not initialized, so do not find
2074          * the namespace objects, or handle the events.
2075          */
2076         ret = acpi_ec_setup(ec, NULL, false);
2077         if (ret) {
2078                 acpi_ec_free(ec);
2079                 goto out;
2080         }
2081
2082         boot_ec = ec;
2083         boot_ec_is_ecdt = true;
2084
2085         pr_info("Boot ECDT EC used to handle transactions\n");
2086
2087 out:
2088         acpi_put_table((struct acpi_table_header *)ecdt_ptr);
2089 }
2090
2091 #ifdef CONFIG_PM_SLEEP
2092 static int acpi_ec_suspend(struct device *dev)
2093 {
2094         struct acpi_ec *ec =
2095                 acpi_driver_data(to_acpi_device(dev));
2096
2097         if (!pm_suspend_no_platform() && ec_freeze_events)
2098                 acpi_ec_disable_event(ec);
2099         return 0;
2100 }
2101
2102 static int acpi_ec_suspend_noirq(struct device *dev)
2103 {
2104         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2105
2106         /*
2107          * The SCI handler doesn't run at this point, so the GPE can be
2108          * masked at the low level without side effects.
2109          */
2110         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2111             ec->gpe >= 0 && ec->reference_count >= 1)
2112                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
2113
2114         acpi_ec_enter_noirq(ec);
2115
2116         return 0;
2117 }
2118
2119 static int acpi_ec_resume_noirq(struct device *dev)
2120 {
2121         struct acpi_ec *ec = acpi_driver_data(to_acpi_device(dev));
2122
2123         acpi_ec_leave_noirq(ec);
2124
2125         if (ec_no_wakeup && test_bit(EC_FLAGS_STARTED, &ec->flags) &&
2126             ec->gpe >= 0 && ec->reference_count >= 1)
2127                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
2128
2129         return 0;
2130 }
2131
2132 static int acpi_ec_resume(struct device *dev)
2133 {
2134         struct acpi_ec *ec =
2135                 acpi_driver_data(to_acpi_device(dev));
2136
2137         acpi_ec_enable_event(ec);
2138         return 0;
2139 }
2140
2141 void acpi_ec_mark_gpe_for_wake(void)
2142 {
2143         if (first_ec && !ec_no_wakeup)
2144                 acpi_mark_gpe_for_wake(NULL, first_ec->gpe);
2145 }
2146 EXPORT_SYMBOL_GPL(acpi_ec_mark_gpe_for_wake);
2147
2148 void acpi_ec_set_gpe_wake_mask(u8 action)
2149 {
2150         if (pm_suspend_no_platform() && first_ec && !ec_no_wakeup)
2151                 acpi_set_gpe_wake_mask(NULL, first_ec->gpe, action);
2152 }
2153
2154 static bool acpi_ec_work_in_progress(struct acpi_ec *ec)
2155 {
2156         return ec->events_in_progress + ec->queries_in_progress > 0;
2157 }
2158
2159 bool acpi_ec_dispatch_gpe(void)
2160 {
2161         bool work_in_progress = false;
2162
2163         if (!first_ec)
2164                 return acpi_any_gpe_status_set(U32_MAX);
2165
2166         /*
2167          * Report wakeup if the status bit is set for any enabled GPE other
2168          * than the EC one.
2169          */
2170         if (acpi_any_gpe_status_set(first_ec->gpe))
2171                 return true;
2172
2173         /*
2174          * Cancel the SCI wakeup and process all pending events in case there
2175          * are any wakeup ones in there.
2176          *
2177          * Note that if any non-EC GPEs are active at this point, the SCI will
2178          * retrigger after the rearming in acpi_s2idle_wake(), so no events
2179          * should be missed by canceling the wakeup here.
2180          */
2181         pm_system_cancel_wakeup();
2182
2183         /*
2184          * Dispatch the EC GPE in-band, but do not report wakeup in any case
2185          * to allow the caller to process events properly after that.
2186          */
2187         spin_lock_irq(&first_ec->lock);
2188
2189         if (acpi_ec_gpe_status_set(first_ec)) {
2190                 pm_pr_dbg("ACPI EC GPE status set\n");
2191
2192                 clear_gpe_and_advance_transaction(first_ec, false);
2193                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2194         }
2195
2196         spin_unlock_irq(&first_ec->lock);
2197
2198         if (!work_in_progress)
2199                 return false;
2200
2201         pm_pr_dbg("ACPI EC GPE dispatched\n");
2202
2203         /* Drain EC work. */
2204         do {
2205                 acpi_ec_flush_work();
2206
2207                 pm_pr_dbg("ACPI EC work flushed\n");
2208
2209                 spin_lock_irq(&first_ec->lock);
2210
2211                 work_in_progress = acpi_ec_work_in_progress(first_ec);
2212
2213                 spin_unlock_irq(&first_ec->lock);
2214         } while (work_in_progress && !pm_wakeup_pending());
2215
2216         return false;
2217 }
2218 #endif /* CONFIG_PM_SLEEP */
2219
2220 static const struct dev_pm_ops acpi_ec_pm = {
2221         SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend_noirq, acpi_ec_resume_noirq)
2222         SET_SYSTEM_SLEEP_PM_OPS(acpi_ec_suspend, acpi_ec_resume)
2223 };
2224
2225 static int param_set_event_clearing(const char *val,
2226                                     const struct kernel_param *kp)
2227 {
2228         int result = 0;
2229
2230         if (!strncmp(val, "status", sizeof("status") - 1)) {
2231                 ec_event_clearing = ACPI_EC_EVT_TIMING_STATUS;
2232                 pr_info("Assuming SCI_EVT clearing on EC_SC accesses\n");
2233         } else if (!strncmp(val, "query", sizeof("query") - 1)) {
2234                 ec_event_clearing = ACPI_EC_EVT_TIMING_QUERY;
2235                 pr_info("Assuming SCI_EVT clearing on QR_EC writes\n");
2236         } else if (!strncmp(val, "event", sizeof("event") - 1)) {
2237                 ec_event_clearing = ACPI_EC_EVT_TIMING_EVENT;
2238                 pr_info("Assuming SCI_EVT clearing on event reads\n");
2239         } else
2240                 result = -EINVAL;
2241         return result;
2242 }
2243
2244 static int param_get_event_clearing(char *buffer,
2245                                     const struct kernel_param *kp)
2246 {
2247         switch (ec_event_clearing) {
2248         case ACPI_EC_EVT_TIMING_STATUS:
2249                 return sprintf(buffer, "status\n");
2250         case ACPI_EC_EVT_TIMING_QUERY:
2251                 return sprintf(buffer, "query\n");
2252         case ACPI_EC_EVT_TIMING_EVENT:
2253                 return sprintf(buffer, "event\n");
2254         default:
2255                 return sprintf(buffer, "invalid\n");
2256         }
2257         return 0;
2258 }
2259
2260 module_param_call(ec_event_clearing, param_set_event_clearing, param_get_event_clearing,
2261                   NULL, 0644);
2262 MODULE_PARM_DESC(ec_event_clearing, "Assumed SCI_EVT clearing timing");
2263
2264 static struct acpi_driver acpi_ec_driver = {
2265         .name = "ec",
2266         .class = ACPI_EC_CLASS,
2267         .ids = ec_device_ids,
2268         .ops = {
2269                 .add = acpi_ec_add,
2270                 .remove = acpi_ec_remove,
2271                 },
2272         .drv.pm = &acpi_ec_pm,
2273 };
2274
2275 static void acpi_ec_destroy_workqueues(void)
2276 {
2277         if (ec_wq) {
2278                 destroy_workqueue(ec_wq);
2279                 ec_wq = NULL;
2280         }
2281         if (ec_query_wq) {
2282                 destroy_workqueue(ec_query_wq);
2283                 ec_query_wq = NULL;
2284         }
2285 }
2286
2287 static int acpi_ec_init_workqueues(void)
2288 {
2289         if (!ec_wq)
2290                 ec_wq = alloc_ordered_workqueue("kec", 0);
2291
2292         if (!ec_query_wq)
2293                 ec_query_wq = alloc_workqueue("kec_query", 0, ec_max_queries);
2294
2295         if (!ec_wq || !ec_query_wq) {
2296                 acpi_ec_destroy_workqueues();
2297                 return -ENODEV;
2298         }
2299         return 0;
2300 }
2301
2302 static const struct dmi_system_id acpi_ec_no_wakeup[] = {
2303         {
2304                 .matches = {
2305                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2306                         DMI_MATCH(DMI_PRODUCT_FAMILY, "Thinkpad X1 Carbon 6th"),
2307                 },
2308         },
2309         {
2310                 .matches = {
2311                         DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
2312                         DMI_MATCH(DMI_PRODUCT_FAMILY, "ThinkPad X1 Yoga 3rd"),
2313                 },
2314         },
2315         {
2316                 .matches = {
2317                         DMI_MATCH(DMI_SYS_VENDOR, "HP"),
2318                         DMI_MATCH(DMI_PRODUCT_FAMILY, "103C_5336AN HP ZHAN 66 Pro"),
2319                 },
2320         },
2321         /*
2322          * Lenovo Legion Go S; touchscreen blocks HW sleep when woken up from EC
2323          * https://gitlab.freedesktop.org/drm/amd/-/issues/3929
2324          */
2325         {
2326                 .matches = {
2327                         DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"),
2328                         DMI_MATCH(DMI_PRODUCT_NAME, "83L3"),
2329                 }
2330         },
2331         {
2332                 .matches = {
2333                         DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"),
2334                         DMI_MATCH(DMI_PRODUCT_NAME, "83N6"),
2335                 }
2336         },
2337         {
2338                 .matches = {
2339                         DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"),
2340                         DMI_MATCH(DMI_PRODUCT_NAME, "83Q2"),
2341                 }
2342         },
2343         {
2344                 .matches = {
2345                         DMI_MATCH(DMI_BOARD_VENDOR, "LENOVO"),
2346                         DMI_MATCH(DMI_PRODUCT_NAME, "83Q3"),
2347                 }
2348         },
2349         {
2350                 // TUXEDO InfinityBook Pro AMD Gen9
2351                 .matches = {
2352                         DMI_MATCH(DMI_BOARD_NAME, "GXxHRXx"),
2353                 },
2354         },
2355         { },
2356 };
2357
2358 void __init acpi_ec_init(void)
2359 {
2360         int result;
2361
2362         result = acpi_ec_init_workqueues();
2363         if (result)
2364                 return;
2365
2366         /*
2367          * Disable EC wakeup on following systems to prevent periodic
2368          * wakeup from EC GPE.
2369          */
2370         if (dmi_check_system(acpi_ec_no_wakeup)) {
2371                 ec_no_wakeup = true;
2372                 pr_debug("Disabling EC wakeup on suspend-to-idle\n");
2373         }
2374
2375         /* Driver must be registered after acpi_ec_init_workqueues(). */
2376         acpi_bus_register_driver(&acpi_ec_driver);
2377
2378         acpi_ec_ecdt_start();
2379 }
2380
2381 /* EC driver currently not unloadable */
2382 #if 0
2383 static void __exit acpi_ec_exit(void)
2384 {
2385
2386         acpi_bus_unregister_driver(&acpi_ec_driver);
2387         acpi_ec_destroy_workqueues();
2388 }
2389 #endif  /* 0 */