linux/kernel/irq/manage.c
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   1/*
   2 * linux/kernel/irq/manage.c
   3 *
   4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5 * Copyright (C) 2005-2006 Thomas Gleixner
   6 *
   7 * This file contains driver APIs to the irq subsystem.
   8 */
   9
  10#define pr_fmt(fmt) "genirq: " fmt
  11
  12#include <linux/irq.h>
  13#include <linux/kthread.h>
  14#include <linux/module.h>
  15#include <linux/random.h>
  16#include <linux/interrupt.h>
  17#include <linux/slab.h>
  18#include <linux/sched.h>
  19#include <linux/sched/rt.h>
  20#include <linux/task_work.h>
  21
  22#include "internals.h"
  23
  24#ifdef CONFIG_IRQ_FORCED_THREADING
  25__read_mostly bool force_irqthreads;
  26
  27static int __init setup_forced_irqthreads(char *arg)
  28{
  29        force_irqthreads = true;
  30        return 0;
  31}
  32early_param("threadirqs", setup_forced_irqthreads);
  33#endif
  34
  35/**
  36 *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  37 *      @irq: interrupt number to wait for
  38 *
  39 *      This function waits for any pending IRQ handlers for this interrupt
  40 *      to complete before returning. If you use this function while
  41 *      holding a resource the IRQ handler may need you will deadlock.
  42 *
  43 *      This function may be called - with care - from IRQ context.
  44 */
  45void synchronize_irq(unsigned int irq)
  46{
  47        struct irq_desc *desc = irq_to_desc(irq);
  48        bool inprogress;
  49
  50        if (!desc)
  51                return;
  52
  53        do {
  54                unsigned long flags;
  55
  56                /*
  57                 * Wait until we're out of the critical section.  This might
  58                 * give the wrong answer due to the lack of memory barriers.
  59                 */
  60                while (irqd_irq_inprogress(&desc->irq_data))
  61                        cpu_relax();
  62
  63                /* Ok, that indicated we're done: double-check carefully. */
  64                raw_spin_lock_irqsave(&desc->lock, flags);
  65                inprogress = irqd_irq_inprogress(&desc->irq_data);
  66                raw_spin_unlock_irqrestore(&desc->lock, flags);
  67
  68                /* Oops, that failed? */
  69        } while (inprogress);
  70
  71        /*
  72         * We made sure that no hardirq handler is running. Now verify
  73         * that no threaded handlers are active.
  74         */
  75        wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
  76}
  77EXPORT_SYMBOL(synchronize_irq);
  78
  79#ifdef CONFIG_SMP
  80cpumask_var_t irq_default_affinity;
  81
  82/**
  83 *      irq_can_set_affinity - Check if the affinity of a given irq can be set
  84 *      @irq:           Interrupt to check
  85 *
  86 */
  87int irq_can_set_affinity(unsigned int irq)
  88{
  89        struct irq_desc *desc = irq_to_desc(irq);
  90
  91        if (!desc || !irqd_can_balance(&desc->irq_data) ||
  92            !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
  93                return 0;
  94
  95        return 1;
  96}
  97
  98/**
  99 *      irq_set_thread_affinity - Notify irq threads to adjust affinity
 100 *      @desc:          irq descriptor which has affitnity changed
 101 *
 102 *      We just set IRQTF_AFFINITY and delegate the affinity setting
 103 *      to the interrupt thread itself. We can not call
 104 *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 105 *      code can be called from hard interrupt context.
 106 */
 107void irq_set_thread_affinity(struct irq_desc *desc)
 108{
 109        struct irqaction *action = desc->action;
 110
 111        while (action) {
 112                if (action->thread)
 113                        set_bit(IRQTF_AFFINITY, &action->thread_flags);
 114                action = action->next;
 115        }
 116}
 117
 118#ifdef CONFIG_GENERIC_PENDING_IRQ
 119static inline bool irq_can_move_pcntxt(struct irq_data *data)
 120{
 121        return irqd_can_move_in_process_context(data);
 122}
 123static inline bool irq_move_pending(struct irq_data *data)
 124{
 125        return irqd_is_setaffinity_pending(data);
 126}
 127static inline void
 128irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 129{
 130        cpumask_copy(desc->pending_mask, mask);
 131}
 132static inline void
 133irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 134{
 135        cpumask_copy(mask, desc->pending_mask);
 136}
 137#else
 138static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 139static inline bool irq_move_pending(struct irq_data *data) { return false; }
 140static inline void
 141irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 142static inline void
 143irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 144#endif
 145
 146int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 147                        bool force)
 148{
 149        struct irq_desc *desc = irq_data_to_desc(data);
 150        struct irq_chip *chip = irq_data_get_irq_chip(data);
 151        int ret;
 152
 153        ret = chip->irq_set_affinity(data, mask, false);
 154        switch (ret) {
 155        case IRQ_SET_MASK_OK:
 156                cpumask_copy(data->affinity, mask);
 157        case IRQ_SET_MASK_OK_NOCOPY:
 158                irq_set_thread_affinity(desc);
 159                ret = 0;
 160        }
 161
 162        return ret;
 163}
 164
 165int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
 166{
 167        struct irq_chip *chip = irq_data_get_irq_chip(data);
 168        struct irq_desc *desc = irq_data_to_desc(data);
 169        int ret = 0;
 170
 171        if (!chip || !chip->irq_set_affinity)
 172                return -EINVAL;
 173
 174        if (irq_can_move_pcntxt(data)) {
 175                ret = irq_do_set_affinity(data, mask, false);
 176        } else {
 177                irqd_set_move_pending(data);
 178                irq_copy_pending(desc, mask);
 179        }
 180
 181        if (desc->affinity_notify) {
 182                kref_get(&desc->affinity_notify->kref);
 183                schedule_work(&desc->affinity_notify->work);
 184        }
 185        irqd_set(data, IRQD_AFFINITY_SET);
 186
 187        return ret;
 188}
 189
 190/**
 191 *      irq_set_affinity - Set the irq affinity of a given irq
 192 *      @irq:           Interrupt to set affinity
 193 *      @mask:          cpumask
 194 *
 195 */
 196int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
 197{
 198        struct irq_desc *desc = irq_to_desc(irq);
 199        unsigned long flags;
 200        int ret;
 201
 202        if (!desc)
 203                return -EINVAL;
 204
 205        raw_spin_lock_irqsave(&desc->lock, flags);
 206        ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
 207        raw_spin_unlock_irqrestore(&desc->lock, flags);
 208        return ret;
 209}
 210
 211int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 212{
 213        unsigned long flags;
 214        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 215
 216        if (!desc)
 217                return -EINVAL;
 218        desc->affinity_hint = m;
 219        irq_put_desc_unlock(desc, flags);
 220        return 0;
 221}
 222EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 223
 224static void irq_affinity_notify(struct work_struct *work)
 225{
 226        struct irq_affinity_notify *notify =
 227                container_of(work, struct irq_affinity_notify, work);
 228        struct irq_desc *desc = irq_to_desc(notify->irq);
 229        cpumask_var_t cpumask;
 230        unsigned long flags;
 231
 232        if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 233                goto out;
 234
 235        raw_spin_lock_irqsave(&desc->lock, flags);
 236        if (irq_move_pending(&desc->irq_data))
 237                irq_get_pending(cpumask, desc);
 238        else
 239                cpumask_copy(cpumask, desc->irq_data.affinity);
 240        raw_spin_unlock_irqrestore(&desc->lock, flags);
 241
 242        notify->notify(notify, cpumask);
 243
 244        free_cpumask_var(cpumask);
 245out:
 246        kref_put(&notify->kref, notify->release);
 247}
 248
 249/**
 250 *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 251 *      @irq:           Interrupt for which to enable/disable notification
 252 *      @notify:        Context for notification, or %NULL to disable
 253 *                      notification.  Function pointers must be initialised;
 254 *                      the other fields will be initialised by this function.
 255 *
 256 *      Must be called in process context.  Notification may only be enabled
 257 *      after the IRQ is allocated and must be disabled before the IRQ is
 258 *      freed using free_irq().
 259 */
 260int
 261irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 262{
 263        struct irq_desc *desc = irq_to_desc(irq);
 264        struct irq_affinity_notify *old_notify;
 265        unsigned long flags;
 266
 267        /* The release function is promised process context */
 268        might_sleep();
 269
 270        if (!desc)
 271                return -EINVAL;
 272
 273        /* Complete initialisation of *notify */
 274        if (notify) {
 275                notify->irq = irq;
 276                kref_init(&notify->kref);
 277                INIT_WORK(&notify->work, irq_affinity_notify);
 278        }
 279
 280        raw_spin_lock_irqsave(&desc->lock, flags);
 281        old_notify = desc->affinity_notify;
 282        desc->affinity_notify = notify;
 283        raw_spin_unlock_irqrestore(&desc->lock, flags);
 284
 285        if (old_notify)
 286                kref_put(&old_notify->kref, old_notify->release);
 287
 288        return 0;
 289}
 290EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 291
 292#ifndef CONFIG_AUTO_IRQ_AFFINITY
 293/*
 294 * Generic version of the affinity autoselector.
 295 */
 296static int
 297setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 298{
 299        struct cpumask *set = irq_default_affinity;
 300        int node = desc->irq_data.node;
 301
 302        /* Excludes PER_CPU and NO_BALANCE interrupts */
 303        if (!irq_can_set_affinity(irq))
 304                return 0;
 305
 306        /*
 307         * Preserve an userspace affinity setup, but make sure that
 308         * one of the targets is online.
 309         */
 310        if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 311                if (cpumask_intersects(desc->irq_data.affinity,
 312                                       cpu_online_mask))
 313                        set = desc->irq_data.affinity;
 314                else
 315                        irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 316        }
 317
 318        cpumask_and(mask, cpu_online_mask, set);
 319        if (node != NUMA_NO_NODE) {
 320                const struct cpumask *nodemask = cpumask_of_node(node);
 321
 322                /* make sure at least one of the cpus in nodemask is online */
 323                if (cpumask_intersects(mask, nodemask))
 324                        cpumask_and(mask, mask, nodemask);
 325        }
 326        irq_do_set_affinity(&desc->irq_data, mask, false);
 327        return 0;
 328}
 329#else
 330static inline int
 331setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 332{
 333        return irq_select_affinity(irq);
 334}
 335#endif
 336
 337/*
 338 * Called when affinity is set via /proc/irq
 339 */
 340int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 341{
 342        struct irq_desc *desc = irq_to_desc(irq);
 343        unsigned long flags;
 344        int ret;
 345
 346        raw_spin_lock_irqsave(&desc->lock, flags);
 347        ret = setup_affinity(irq, desc, mask);
 348        raw_spin_unlock_irqrestore(&desc->lock, flags);
 349        return ret;
 350}
 351
 352#else
 353static inline int
 354setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 355{
 356        return 0;
 357}
 358#endif
 359
 360void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 361{
 362        if (suspend) {
 363                if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 364                        return;
 365                desc->istate |= IRQS_SUSPENDED;
 366        }
 367
 368        if (!desc->depth++)
 369                irq_disable(desc);
 370}
 371
 372static int __disable_irq_nosync(unsigned int irq)
 373{
 374        unsigned long flags;
 375        struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 376
 377        if (!desc)
 378                return -EINVAL;
 379        __disable_irq(desc, irq, false);
 380        irq_put_desc_busunlock(desc, flags);
 381        return 0;
 382}
 383
 384/**
 385 *      disable_irq_nosync - disable an irq without waiting
 386 *      @irq: Interrupt to disable
 387 *
 388 *      Disable the selected interrupt line.  Disables and Enables are
 389 *      nested.
 390 *      Unlike disable_irq(), this function does not ensure existing
 391 *      instances of the IRQ handler have completed before returning.
 392 *
 393 *      This function may be called from IRQ context.
 394 */
 395void disable_irq_nosync(unsigned int irq)
 396{
 397        __disable_irq_nosync(irq);
 398}
 399EXPORT_SYMBOL(disable_irq_nosync);
 400
 401/**
 402 *      disable_irq - disable an irq and wait for completion
 403 *      @irq: Interrupt to disable
 404 *
 405 *      Disable the selected interrupt line.  Enables and Disables are
 406 *      nested.
 407 *      This function waits for any pending IRQ handlers for this interrupt
 408 *      to complete before returning. If you use this function while
 409 *      holding a resource the IRQ handler may need you will deadlock.
 410 *
 411 *      This function may be called - with care - from IRQ context.
 412 */
 413void disable_irq(unsigned int irq)
 414{
 415        if (!__disable_irq_nosync(irq))
 416                synchronize_irq(irq);
 417}
 418EXPORT_SYMBOL(disable_irq);
 419
 420void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
 421{
 422        if (resume) {
 423                if (!(desc->istate & IRQS_SUSPENDED)) {
 424                        if (!desc->action)
 425                                return;
 426                        if (!(desc->action->flags & IRQF_FORCE_RESUME))
 427                                return;
 428                        /* Pretend that it got disabled ! */
 429                        desc->depth++;
 430                }
 431                desc->istate &= ~IRQS_SUSPENDED;
 432        }
 433
 434        switch (desc->depth) {
 435        case 0:
 436 err_out:
 437                WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 438                break;
 439        case 1: {
 440                if (desc->istate & IRQS_SUSPENDED)
 441                        goto err_out;
 442                /* Prevent probing on this irq: */
 443                irq_settings_set_noprobe(desc);
 444                irq_enable(desc);
 445                check_irq_resend(desc, irq);
 446                /* fall-through */
 447        }
 448        default:
 449                desc->depth--;
 450        }
 451}
 452
 453/**
 454 *      enable_irq - enable handling of an irq
 455 *      @irq: Interrupt to enable
 456 *
 457 *      Undoes the effect of one call to disable_irq().  If this
 458 *      matches the last disable, processing of interrupts on this
 459 *      IRQ line is re-enabled.
 460 *
 461 *      This function may be called from IRQ context only when
 462 *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 463 */
 464void enable_irq(unsigned int irq)
 465{
 466        unsigned long flags;
 467        struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 468
 469        if (!desc)
 470                return;
 471        if (WARN(!desc->irq_data.chip,
 472                 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 473                goto out;
 474
 475        __enable_irq(desc, irq, false);
 476out:
 477        irq_put_desc_busunlock(desc, flags);
 478}
 479EXPORT_SYMBOL(enable_irq);
 480
 481static int set_irq_wake_real(unsigned int irq, unsigned int on)
 482{
 483        struct irq_desc *desc = irq_to_desc(irq);
 484        int ret = -ENXIO;
 485
 486        if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 487                return 0;
 488
 489        if (desc->irq_data.chip->irq_set_wake)
 490                ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 491
 492        return ret;
 493}
 494
 495/**
 496 *      irq_set_irq_wake - control irq power management wakeup
 497 *      @irq:   interrupt to control
 498 *      @on:    enable/disable power management wakeup
 499 *
 500 *      Enable/disable power management wakeup mode, which is
 501 *      disabled by default.  Enables and disables must match,
 502 *      just as they match for non-wakeup mode support.
 503 *
 504 *      Wakeup mode lets this IRQ wake the system from sleep
 505 *      states like "suspend to RAM".
 506 */
 507int irq_set_irq_wake(unsigned int irq, unsigned int on)
 508{
 509        unsigned long flags;
 510        struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 511        int ret = 0;
 512
 513        if (!desc)
 514                return -EINVAL;
 515
 516        /* wakeup-capable irqs can be shared between drivers that
 517         * don't need to have the same sleep mode behaviors.
 518         */
 519        if (on) {
 520                if (desc->wake_depth++ == 0) {
 521                        ret = set_irq_wake_real(irq, on);
 522                        if (ret)
 523                                desc->wake_depth = 0;
 524                        else
 525                                irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 526                }
 527        } else {
 528                if (desc->wake_depth == 0) {
 529                        WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 530                } else if (--desc->wake_depth == 0) {
 531                        ret = set_irq_wake_real(irq, on);
 532                        if (ret)
 533                                desc->wake_depth = 1;
 534                        else
 535                                irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 536                }
 537        }
 538        irq_put_desc_busunlock(desc, flags);
 539        return ret;
 540}
 541EXPORT_SYMBOL(irq_set_irq_wake);
 542
 543/*
 544 * Internal function that tells the architecture code whether a
 545 * particular irq has been exclusively allocated or is available
 546 * for driver use.
 547 */
 548int can_request_irq(unsigned int irq, unsigned long irqflags)
 549{
 550        unsigned long flags;
 551        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 552        int canrequest = 0;
 553
 554        if (!desc)
 555                return 0;
 556
 557        if (irq_settings_can_request(desc)) {
 558                if (!desc->action ||
 559                    irqflags & desc->action->flags & IRQF_SHARED)
 560                        canrequest = 1;
 561        }
 562        irq_put_desc_unlock(desc, flags);
 563        return canrequest;
 564}
 565
 566int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 567                      unsigned long flags)
 568{
 569        struct irq_chip *chip = desc->irq_data.chip;
 570        int ret, unmask = 0;
 571
 572        if (!chip || !chip->irq_set_type) {
 573                /*
 574                 * IRQF_TRIGGER_* but the PIC does not support multiple
 575                 * flow-types?
 576                 */
 577                pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 578                         chip ? (chip->name ? : "unknown") : "unknown");
 579                return 0;
 580        }
 581
 582        flags &= IRQ_TYPE_SENSE_MASK;
 583
 584        if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 585                if (!irqd_irq_masked(&desc->irq_data))
 586                        mask_irq(desc);
 587                if (!irqd_irq_disabled(&desc->irq_data))
 588                        unmask = 1;
 589        }
 590
 591        /* caller masked out all except trigger mode flags */
 592        ret = chip->irq_set_type(&desc->irq_data, flags);
 593
 594        switch (ret) {
 595        case IRQ_SET_MASK_OK:
 596                irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 597                irqd_set(&desc->irq_data, flags);
 598
 599        case IRQ_SET_MASK_OK_NOCOPY:
 600                flags = irqd_get_trigger_type(&desc->irq_data);
 601                irq_settings_set_trigger_mask(desc, flags);
 602                irqd_clear(&desc->irq_data, IRQD_LEVEL);
 603                irq_settings_clr_level(desc);
 604                if (flags & IRQ_TYPE_LEVEL_MASK) {
 605                        irq_settings_set_level(desc);
 606                        irqd_set(&desc->irq_data, IRQD_LEVEL);
 607                }
 608
 609                ret = 0;
 610                break;
 611        default:
 612                pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 613                       flags, irq, chip->irq_set_type);
 614        }
 615        if (unmask)
 616                unmask_irq(desc);
 617        return ret;
 618}
 619
 620#ifdef CONFIG_HARDIRQS_SW_RESEND
 621int irq_set_parent(int irq, int parent_irq)
 622{
 623        unsigned long flags;
 624        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 625
 626        if (!desc)
 627                return -EINVAL;
 628
 629        desc->parent_irq = parent_irq;
 630
 631        irq_put_desc_unlock(desc, flags);
 632        return 0;
 633}
 634#endif
 635
 636/*
 637 * Default primary interrupt handler for threaded interrupts. Is
 638 * assigned as primary handler when request_threaded_irq is called
 639 * with handler == NULL. Useful for oneshot interrupts.
 640 */
 641static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 642{
 643        return IRQ_WAKE_THREAD;
 644}
 645
 646/*
 647 * Primary handler for nested threaded interrupts. Should never be
 648 * called.
 649 */
 650static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 651{
 652        WARN(1, "Primary handler called for nested irq %d\n", irq);
 653        return IRQ_NONE;
 654}
 655
 656static int irq_wait_for_interrupt(struct irqaction *action)
 657{
 658        set_current_state(TASK_INTERRUPTIBLE);
 659
 660        while (!kthread_should_stop()) {
 661
 662                if (test_and_clear_bit(IRQTF_RUNTHREAD,
 663                                       &action->thread_flags)) {
 664                        __set_current_state(TASK_RUNNING);
 665                        return 0;
 666                }
 667                schedule();
 668                set_current_state(TASK_INTERRUPTIBLE);
 669        }
 670        __set_current_state(TASK_RUNNING);
 671        return -1;
 672}
 673
 674/*
 675 * Oneshot interrupts keep the irq line masked until the threaded
 676 * handler finished. unmask if the interrupt has not been disabled and
 677 * is marked MASKED.
 678 */
 679static void irq_finalize_oneshot(struct irq_desc *desc,
 680                                 struct irqaction *action)
 681{
 682        if (!(desc->istate & IRQS_ONESHOT))
 683                return;
 684again:
 685        chip_bus_lock(desc);
 686        raw_spin_lock_irq(&desc->lock);
 687
 688        /*
 689         * Implausible though it may be we need to protect us against
 690         * the following scenario:
 691         *
 692         * The thread is faster done than the hard interrupt handler
 693         * on the other CPU. If we unmask the irq line then the
 694         * interrupt can come in again and masks the line, leaves due
 695         * to IRQS_INPROGRESS and the irq line is masked forever.
 696         *
 697         * This also serializes the state of shared oneshot handlers
 698         * versus "desc->threads_onehsot |= action->thread_mask;" in
 699         * irq_wake_thread(). See the comment there which explains the
 700         * serialization.
 701         */
 702        if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 703                raw_spin_unlock_irq(&desc->lock);
 704                chip_bus_sync_unlock(desc);
 705                cpu_relax();
 706                goto again;
 707        }
 708
 709        /*
 710         * Now check again, whether the thread should run. Otherwise
 711         * we would clear the threads_oneshot bit of this thread which
 712         * was just set.
 713         */
 714        if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 715                goto out_unlock;
 716
 717        desc->threads_oneshot &= ~action->thread_mask;
 718
 719        if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 720            irqd_irq_masked(&desc->irq_data))
 721                unmask_irq(desc);
 722
 723out_unlock:
 724        raw_spin_unlock_irq(&desc->lock);
 725        chip_bus_sync_unlock(desc);
 726}
 727
 728#ifdef CONFIG_SMP
 729/*
 730 * Check whether we need to chasnge the affinity of the interrupt thread.
 731 */
 732static void
 733irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 734{
 735        cpumask_var_t mask;
 736        bool valid = true;
 737
 738        if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 739                return;
 740
 741        /*
 742         * In case we are out of memory we set IRQTF_AFFINITY again and
 743         * try again next time
 744         */
 745        if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 746                set_bit(IRQTF_AFFINITY, &action->thread_flags);
 747                return;
 748        }
 749
 750        raw_spin_lock_irq(&desc->lock);
 751        /*
 752         * This code is triggered unconditionally. Check the affinity
 753         * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 754         */
 755        if (desc->irq_data.affinity)
 756                cpumask_copy(mask, desc->irq_data.affinity);
 757        else
 758                valid = false;
 759        raw_spin_unlock_irq(&desc->lock);
 760
 761        if (valid)
 762                set_cpus_allowed_ptr(current, mask);
 763        free_cpumask_var(mask);
 764}
 765#else
 766static inline void
 767irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 768#endif
 769
 770/*
 771 * Interrupts which are not explicitely requested as threaded
 772 * interrupts rely on the implicit bh/preempt disable of the hard irq
 773 * context. So we need to disable bh here to avoid deadlocks and other
 774 * side effects.
 775 */
 776static irqreturn_t
 777irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 778{
 779        irqreturn_t ret;
 780
 781        local_bh_disable();
 782        ret = action->thread_fn(action->irq, action->dev_id);
 783        irq_finalize_oneshot(desc, action);
 784        local_bh_enable();
 785        return ret;
 786}
 787
 788/*
 789 * Interrupts explicitely requested as threaded interupts want to be
 790 * preemtible - many of them need to sleep and wait for slow busses to
 791 * complete.
 792 */
 793static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 794                struct irqaction *action)
 795{
 796        irqreturn_t ret;
 797
 798        ret = action->thread_fn(action->irq, action->dev_id);
 799        irq_finalize_oneshot(desc, action);
 800        return ret;
 801}
 802
 803static void wake_threads_waitq(struct irq_desc *desc)
 804{
 805        if (atomic_dec_and_test(&desc->threads_active) &&
 806            waitqueue_active(&desc->wait_for_threads))
 807                wake_up(&desc->wait_for_threads);
 808}
 809
 810static void irq_thread_dtor(struct callback_head *unused)
 811{
 812        struct task_struct *tsk = current;
 813        struct irq_desc *desc;
 814        struct irqaction *action;
 815
 816        if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 817                return;
 818
 819        action = kthread_data(tsk);
 820
 821        pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 822               tsk->comm, tsk->pid, action->irq);
 823
 824
 825        desc = irq_to_desc(action->irq);
 826        /*
 827         * If IRQTF_RUNTHREAD is set, we need to decrement
 828         * desc->threads_active and wake possible waiters.
 829         */
 830        if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 831                wake_threads_waitq(desc);
 832
 833        /* Prevent a stale desc->threads_oneshot */
 834        irq_finalize_oneshot(desc, action);
 835}
 836
 837/*
 838 * Interrupt handler thread
 839 */
 840static int irq_thread(void *data)
 841{
 842        struct callback_head on_exit_work;
 843        struct irqaction *action = data;
 844        struct irq_desc *desc = irq_to_desc(action->irq);
 845        irqreturn_t (*handler_fn)(struct irq_desc *desc,
 846                        struct irqaction *action);
 847
 848        if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 849                                        &action->thread_flags))
 850                handler_fn = irq_forced_thread_fn;
 851        else
 852                handler_fn = irq_thread_fn;
 853
 854        init_task_work(&on_exit_work, irq_thread_dtor);
 855        task_work_add(current, &on_exit_work, false);
 856
 857        irq_thread_check_affinity(desc, action);
 858
 859        while (!irq_wait_for_interrupt(action)) {
 860                irqreturn_t action_ret;
 861
 862                irq_thread_check_affinity(desc, action);
 863
 864                action_ret = handler_fn(desc, action);
 865                if (!noirqdebug)
 866                        note_interrupt(action->irq, desc, action_ret);
 867
 868                wake_threads_waitq(desc);
 869        }
 870
 871        /*
 872         * This is the regular exit path. __free_irq() is stopping the
 873         * thread via kthread_stop() after calling
 874         * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 875         * oneshot mask bit can be set. We cannot verify that as we
 876         * cannot touch the oneshot mask at this point anymore as
 877         * __setup_irq() might have given out currents thread_mask
 878         * again.
 879         */
 880        task_work_cancel(current, irq_thread_dtor);
 881        return 0;
 882}
 883
 884static void irq_setup_forced_threading(struct irqaction *new)
 885{
 886        if (!force_irqthreads)
 887                return;
 888        if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 889                return;
 890
 891        new->flags |= IRQF_ONESHOT;
 892
 893        if (!new->thread_fn) {
 894                set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 895                new->thread_fn = new->handler;
 896                new->handler = irq_default_primary_handler;
 897        }
 898}
 899
 900/*
 901 * Internal function to register an irqaction - typically used to
 902 * allocate special interrupts that are part of the architecture.
 903 */
 904static int
 905__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 906{
 907        struct irqaction *old, **old_ptr;
 908        unsigned long flags, thread_mask = 0;
 909        int ret, nested, shared = 0;
 910        cpumask_var_t mask;
 911
 912        if (!desc)
 913                return -EINVAL;
 914
 915        if (desc->irq_data.chip == &no_irq_chip)
 916                return -ENOSYS;
 917        if (!try_module_get(desc->owner))
 918                return -ENODEV;
 919
 920        /*
 921         * Check whether the interrupt nests into another interrupt
 922         * thread.
 923         */
 924        nested = irq_settings_is_nested_thread(desc);
 925        if (nested) {
 926                if (!new->thread_fn) {
 927                        ret = -EINVAL;
 928                        goto out_mput;
 929                }
 930                /*
 931                 * Replace the primary handler which was provided from
 932                 * the driver for non nested interrupt handling by the
 933                 * dummy function which warns when called.
 934                 */
 935                new->handler = irq_nested_primary_handler;
 936        } else {
 937                if (irq_settings_can_thread(desc))
 938                        irq_setup_forced_threading(new);
 939        }
 940
 941        /*
 942         * Create a handler thread when a thread function is supplied
 943         * and the interrupt does not nest into another interrupt
 944         * thread.
 945         */
 946        if (new->thread_fn && !nested) {
 947                struct task_struct *t;
 948                static const struct sched_param param = {
 949                        .sched_priority = MAX_USER_RT_PRIO/2,
 950                };
 951
 952                t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 953                                   new->name);
 954                if (IS_ERR(t)) {
 955                        ret = PTR_ERR(t);
 956                        goto out_mput;
 957                }
 958
 959                sched_setscheduler(t, SCHED_FIFO, &param);
 960
 961                /*
 962                 * We keep the reference to the task struct even if
 963                 * the thread dies to avoid that the interrupt code
 964                 * references an already freed task_struct.
 965                 */
 966                get_task_struct(t);
 967                new->thread = t;
 968                /*
 969                 * Tell the thread to set its affinity. This is
 970                 * important for shared interrupt handlers as we do
 971                 * not invoke setup_affinity() for the secondary
 972                 * handlers as everything is already set up. Even for
 973                 * interrupts marked with IRQF_NO_BALANCE this is
 974                 * correct as we want the thread to move to the cpu(s)
 975                 * on which the requesting code placed the interrupt.
 976                 */
 977                set_bit(IRQTF_AFFINITY, &new->thread_flags);
 978        }
 979
 980        if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 981                ret = -ENOMEM;
 982                goto out_thread;
 983        }
 984
 985        /*
 986         * Drivers are often written to work w/o knowledge about the
 987         * underlying irq chip implementation, so a request for a
 988         * threaded irq without a primary hard irq context handler
 989         * requires the ONESHOT flag to be set. Some irq chips like
 990         * MSI based interrupts are per se one shot safe. Check the
 991         * chip flags, so we can avoid the unmask dance at the end of
 992         * the threaded handler for those.
 993         */
 994        if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
 995                new->flags &= ~IRQF_ONESHOT;
 996
 997        /*
 998         * The following block of code has to be executed atomically
 999         */
1000        raw_spin_lock_irqsave(&desc->lock, flags);
1001        old_ptr = &desc->action;
1002        old = *old_ptr;
1003        if (old) {
1004                /*
1005                 * Can't share interrupts unless both agree to and are
1006                 * the same type (level, edge, polarity). So both flag
1007                 * fields must have IRQF_SHARED set and the bits which
1008                 * set the trigger type must match. Also all must
1009                 * agree on ONESHOT.
1010                 */
1011                if (!((old->flags & new->flags) & IRQF_SHARED) ||
1012                    ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1013                    ((old->flags ^ new->flags) & IRQF_ONESHOT))
1014                        goto mismatch;
1015
1016                /* All handlers must agree on per-cpuness */
1017                if ((old->flags & IRQF_PERCPU) !=
1018                    (new->flags & IRQF_PERCPU))
1019                        goto mismatch;
1020
1021                /* add new interrupt at end of irq queue */
1022                do {
1023                        /*
1024                         * Or all existing action->thread_mask bits,
1025                         * so we can find the next zero bit for this
1026                         * new action.
1027                         */
1028                        thread_mask |= old->thread_mask;
1029                        old_ptr = &old->next;
1030                        old = *old_ptr;
1031                } while (old);
1032                shared = 1;
1033        }
1034
1035        /*
1036         * Setup the thread mask for this irqaction for ONESHOT. For
1037         * !ONESHOT irqs the thread mask is 0 so we can avoid a
1038         * conditional in irq_wake_thread().
1039         */
1040        if (new->flags & IRQF_ONESHOT) {
1041                /*
1042                 * Unlikely to have 32 resp 64 irqs sharing one line,
1043                 * but who knows.
1044                 */
1045                if (thread_mask == ~0UL) {
1046                        ret = -EBUSY;
1047                        goto out_mask;
1048                }
1049                /*
1050                 * The thread_mask for the action is or'ed to
1051                 * desc->thread_active to indicate that the
1052                 * IRQF_ONESHOT thread handler has been woken, but not
1053                 * yet finished. The bit is cleared when a thread
1054                 * completes. When all threads of a shared interrupt
1055                 * line have completed desc->threads_active becomes
1056                 * zero and the interrupt line is unmasked. See
1057                 * handle.c:irq_wake_thread() for further information.
1058                 *
1059                 * If no thread is woken by primary (hard irq context)
1060                 * interrupt handlers, then desc->threads_active is
1061                 * also checked for zero to unmask the irq line in the
1062                 * affected hard irq flow handlers
1063                 * (handle_[fasteoi|level]_irq).
1064                 *
1065                 * The new action gets the first zero bit of
1066                 * thread_mask assigned. See the loop above which or's
1067                 * all existing action->thread_mask bits.
1068                 */
1069                new->thread_mask = 1 << ffz(thread_mask);
1070
1071        } else if (new->handler == irq_default_primary_handler &&
1072                   !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1073                /*
1074                 * The interrupt was requested with handler = NULL, so
1075                 * we use the default primary handler for it. But it
1076                 * does not have the oneshot flag set. In combination
1077                 * with level interrupts this is deadly, because the
1078                 * default primary handler just wakes the thread, then
1079                 * the irq lines is reenabled, but the device still
1080                 * has the level irq asserted. Rinse and repeat....
1081                 *
1082                 * While this works for edge type interrupts, we play
1083                 * it safe and reject unconditionally because we can't
1084                 * say for sure which type this interrupt really
1085                 * has. The type flags are unreliable as the
1086                 * underlying chip implementation can override them.
1087                 */
1088                pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1089                       irq);
1090                ret = -EINVAL;
1091                goto out_mask;
1092        }
1093
1094        if (!shared) {
1095                init_waitqueue_head(&desc->wait_for_threads);
1096
1097                /* Setup the type (level, edge polarity) if configured: */
1098                if (new->flags & IRQF_TRIGGER_MASK) {
1099                        ret = __irq_set_trigger(desc, irq,
1100                                        new->flags & IRQF_TRIGGER_MASK);
1101
1102                        if (ret)
1103                                goto out_mask;
1104                }
1105
1106                desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1107                                  IRQS_ONESHOT | IRQS_WAITING);
1108                irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1109
1110                if (new->flags & IRQF_PERCPU) {
1111                        irqd_set(&desc->irq_data, IRQD_PER_CPU);
1112                        irq_settings_set_per_cpu(desc);
1113                }
1114
1115                if (new->flags & IRQF_ONESHOT)
1116                        desc->istate |= IRQS_ONESHOT;
1117
1118                if (irq_settings_can_autoenable(desc))
1119                        irq_startup(desc, true);
1120                else
1121                        /* Undo nested disables: */
1122                        desc->depth = 1;
1123
1124                /* Exclude IRQ from balancing if requested */
1125                if (new->flags & IRQF_NOBALANCING) {
1126                        irq_settings_set_no_balancing(desc);
1127                        irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1128                }
1129
1130                /* Set default affinity mask once everything is setup */
1131                setup_affinity(irq, desc, mask);
1132
1133        } else if (new->flags & IRQF_TRIGGER_MASK) {
1134                unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1135                unsigned int omsk = irq_settings_get_trigger_mask(desc);
1136
1137                if (nmsk != omsk)
1138                        /* hope the handler works with current  trigger mode */
1139                        pr_warning("irq %d uses trigger mode %u; requested %u\n",
1140                                   irq, nmsk, omsk);
1141        }
1142
1143        new->irq = irq;
1144        *old_ptr = new;
1145
1146        /* Reset broken irq detection when installing new handler */
1147        desc->irq_count = 0;
1148        desc->irqs_unhandled = 0;
1149
1150        /*
1151         * Check whether we disabled the irq via the spurious handler
1152         * before. Reenable it and give it another chance.
1153         */
1154        if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1155                desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1156                __enable_irq(desc, irq, false);
1157        }
1158
1159        raw_spin_unlock_irqrestore(&desc->lock, flags);
1160
1161        /*
1162         * Strictly no need to wake it up, but hung_task complains
1163         * when no hard interrupt wakes the thread up.
1164         */
1165        if (new->thread)
1166                wake_up_process(new->thread);
1167
1168        register_irq_proc(irq, desc);
1169        new->dir = NULL;
1170        register_handler_proc(irq, new);
1171        free_cpumask_var(mask);
1172
1173        return 0;
1174
1175mismatch:
1176        if (!(new->flags & IRQF_PROBE_SHARED)) {
1177                pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1178                       irq, new->flags, new->name, old->flags, old->name);
1179#ifdef CONFIG_DEBUG_SHIRQ
1180                dump_stack();
1181#endif
1182        }
1183        ret = -EBUSY;
1184
1185out_mask:
1186        raw_spin_unlock_irqrestore(&desc->lock, flags);
1187        free_cpumask_var(mask);
1188
1189out_thread:
1190        if (new->thread) {
1191                struct task_struct *t = new->thread;
1192
1193                new->thread = NULL;
1194                kthread_stop(t);
1195                put_task_struct(t);
1196        }
1197out_mput:
1198        module_put(desc->owner);
1199        return ret;
1200}
1201
1202/**
1203 *      setup_irq - setup an interrupt
1204 *      @irq: Interrupt line to setup
1205 *      @act: irqaction for the interrupt
1206 *
1207 * Used to statically setup interrupts in the early boot process.
1208 */
1209int setup_irq(unsigned int irq, struct irqaction *act)
1210{
1211        int retval;
1212        struct irq_desc *desc = irq_to_desc(irq);
1213
1214        if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1215                return -EINVAL;
1216        chip_bus_lock(desc);
1217        retval = __setup_irq(irq, desc, act);
1218        chip_bus_sync_unlock(desc);
1219
1220        return retval;
1221}
1222EXPORT_SYMBOL_GPL(setup_irq);
1223
1224/*
1225 * Internal function to unregister an irqaction - used to free
1226 * regular and special interrupts that are part of the architecture.
1227 */
1228static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1229{
1230        struct irq_desc *desc = irq_to_desc(irq);
1231        struct irqaction *action, **action_ptr;
1232        unsigned long flags;
1233
1234        WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1235
1236        if (!desc)
1237                return NULL;
1238
1239        raw_spin_lock_irqsave(&desc->lock, flags);
1240
1241        /*
1242         * There can be multiple actions per IRQ descriptor, find the right
1243         * one based on the dev_id:
1244         */
1245        action_ptr = &desc->action;
1246        for (;;) {
1247                action = *action_ptr;
1248
1249                if (!action) {
1250                        WARN(1, "Trying to free already-free IRQ %d\n", irq);
1251                        raw_spin_unlock_irqrestore(&desc->lock, flags);
1252
1253                        return NULL;
1254                }
1255
1256                if (action->dev_id == dev_id)
1257                        break;
1258                action_ptr = &action->next;
1259        }
1260
1261        /* Found it - now remove it from the list of entries: */
1262        *action_ptr = action->next;
1263
1264        /* If this was the last handler, shut down the IRQ line: */
1265        if (!desc->action)
1266                irq_shutdown(desc);
1267
1268#ifdef CONFIG_SMP
1269        /* make sure affinity_hint is cleaned up */
1270        if (WARN_ON_ONCE(desc->affinity_hint))
1271                desc->affinity_hint = NULL;
1272#endif
1273
1274        raw_spin_unlock_irqrestore(&desc->lock, flags);
1275
1276        unregister_handler_proc(irq, action);
1277
1278        /* Make sure it's not being used on another CPU: */
1279        synchronize_irq(irq);
1280
1281#ifdef CONFIG_DEBUG_SHIRQ
1282        /*
1283         * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1284         * event to happen even now it's being freed, so let's make sure that
1285         * is so by doing an extra call to the handler ....
1286         *
1287         * ( We do this after actually deregistering it, to make sure that a
1288         *   'real' IRQ doesn't run in * parallel with our fake. )
1289         */
1290        if (action->flags & IRQF_SHARED) {
1291                local_irq_save(flags);
1292                action->handler(irq, dev_id);
1293                local_irq_restore(flags);
1294        }
1295#endif
1296
1297        if (action->thread) {
1298                kthread_stop(action->thread);
1299                put_task_struct(action->thread);
1300        }
1301
1302        module_put(desc->owner);
1303        return action;
1304}
1305
1306/**
1307 *      remove_irq - free an interrupt
1308 *      @irq: Interrupt line to free
1309 *      @act: irqaction for the interrupt
1310 *
1311 * Used to remove interrupts statically setup by the early boot process.
1312 */
1313void remove_irq(unsigned int irq, struct irqaction *act)
1314{
1315        struct irq_desc *desc = irq_to_desc(irq);
1316
1317        if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1318            __free_irq(irq, act->dev_id);
1319}
1320EXPORT_SYMBOL_GPL(remove_irq);
1321
1322/**
1323 *      free_irq - free an interrupt allocated with request_irq
1324 *      @irq: Interrupt line to free
1325 *      @dev_id: Device identity to free
1326 *
1327 *      Remove an interrupt handler. The handler is removed and if the
1328 *      interrupt line is no longer in use by any driver it is disabled.
1329 *      On a shared IRQ the caller must ensure the interrupt is disabled
1330 *      on the card it drives before calling this function. The function
1331 *      does not return until any executing interrupts for this IRQ
1332 *      have completed.
1333 *
1334 *      This function must not be called from interrupt context.
1335 */
1336void free_irq(unsigned int irq, void *dev_id)
1337{
1338        struct irq_desc *desc = irq_to_desc(irq);
1339
1340        if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1341                return;
1342
1343#ifdef CONFIG_SMP
1344        if (WARN_ON(desc->affinity_notify))
1345                desc->affinity_notify = NULL;
1346#endif
1347
1348        chip_bus_lock(desc);
1349        kfree(__free_irq(irq, dev_id));
1350        chip_bus_sync_unlock(desc);
1351}
1352EXPORT_SYMBOL(free_irq);
1353
1354/**
1355 *      request_threaded_irq - allocate an interrupt line
1356 *      @irq: Interrupt line to allocate
1357 *      @handler: Function to be called when the IRQ occurs.
1358 *                Primary handler for threaded interrupts
1359 *                If NULL and thread_fn != NULL the default
1360 *                primary handler is installed
1361 *      @thread_fn: Function called from the irq handler thread
1362 *                  If NULL, no irq thread is created
1363 *      @irqflags: Interrupt type flags
1364 *      @devname: An ascii name for the claiming device
1365 *      @dev_id: A cookie passed back to the handler function
1366 *
1367 *      This call allocates interrupt resources and enables the
1368 *      interrupt line and IRQ handling. From the point this
1369 *      call is made your handler function may be invoked. Since
1370 *      your handler function must clear any interrupt the board
1371 *      raises, you must take care both to initialise your hardware
1372 *      and to set up the interrupt handler in the right order.
1373 *
1374 *      If you want to set up a threaded irq handler for your device
1375 *      then you need to supply @handler and @thread_fn. @handler is
1376 *      still called in hard interrupt context and has to check
1377 *      whether the interrupt originates from the device. If yes it
1378 *      needs to disable the interrupt on the device and return
1379 *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1380 *      @thread_fn. This split handler design is necessary to support
1381 *      shared interrupts.
1382 *
1383 *      Dev_id must be globally unique. Normally the address of the
1384 *      device data structure is used as the cookie. Since the handler
1385 *      receives this value it makes sense to use it.
1386 *
1387 *      If your interrupt is shared you must pass a non NULL dev_id
1388 *      as this is required when freeing the interrupt.
1389 *
1390 *      Flags:
1391 *
1392 *      IRQF_SHARED             Interrupt is shared
1393 *      IRQF_TRIGGER_*          Specify active edge(s) or level
1394 *
1395 */
1396int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1397                         irq_handler_t thread_fn, unsigned long irqflags,
1398                         const char *devname, void *dev_id)
1399{
1400        struct irqaction *action;
1401        struct irq_desc *desc;
1402        int retval;
1403
1404        /*
1405         * Sanity-check: shared interrupts must pass in a real dev-ID,
1406         * otherwise we'll have trouble later trying to figure out
1407         * which interrupt is which (messes up the interrupt freeing
1408         * logic etc).
1409         */
1410        if ((irqflags & IRQF_SHARED) && !dev_id)
1411                return -EINVAL;
1412
1413        desc = irq_to_desc(irq);
1414        if (!desc)
1415                return -EINVAL;
1416
1417        if (!irq_settings_can_request(desc) ||
1418            WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1419                return -EINVAL;
1420
1421        if (!handler) {
1422                if (!thread_fn)
1423                        return -EINVAL;
1424                handler = irq_default_primary_handler;
1425        }
1426
1427        action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1428        if (!action)
1429                return -ENOMEM;
1430
1431        action->handler = handler;
1432        action->thread_fn = thread_fn;
1433        action->flags = irqflags;
1434        action->name = devname;
1435        action->dev_id = dev_id;
1436
1437        chip_bus_lock(desc);
1438        retval = __setup_irq(irq, desc, action);
1439        chip_bus_sync_unlock(desc);
1440
1441        if (retval)
1442                kfree(action);
1443
1444#ifdef CONFIG_DEBUG_SHIRQ_FIXME
1445        if (!retval && (irqflags & IRQF_SHARED)) {
1446                /*
1447                 * It's a shared IRQ -- the driver ought to be prepared for it
1448                 * to happen immediately, so let's make sure....
1449                 * We disable the irq to make sure that a 'real' IRQ doesn't
1450                 * run in parallel with our fake.
1451                 */
1452                unsigned long flags;
1453
1454                disable_irq(irq);
1455                local_irq_save(flags);
1456
1457                handler(irq, dev_id);
1458
1459                local_irq_restore(flags);
1460                enable_irq(irq);
1461        }
1462#endif
1463        return retval;
1464}
1465EXPORT_SYMBOL(request_threaded_irq);
1466
1467/**
1468 *      request_any_context_irq - allocate an interrupt line
1469 *      @irq: Interrupt line to allocate
1470 *      @handler: Function to be called when the IRQ occurs.
1471 *                Threaded handler for threaded interrupts.
1472 *      @flags: Interrupt type flags
1473 *      @name: An ascii name for the claiming device
1474 *      @dev_id: A cookie passed back to the handler function
1475 *
1476 *      This call allocates interrupt resources and enables the
1477 *      interrupt line and IRQ handling. It selects either a
1478 *      hardirq or threaded handling method depending on the
1479 *      context.
1480 *
1481 *      On failure, it returns a negative value. On success,
1482 *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1483 */
1484int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1485                            unsigned long flags, const char *name, void *dev_id)
1486{
1487        struct irq_desc *desc = irq_to_desc(irq);
1488        int ret;
1489
1490        if (!desc)
1491                return -EINVAL;
1492
1493        if (irq_settings_is_nested_thread(desc)) {
1494                ret = request_threaded_irq(irq, NULL, handler,
1495                                           flags, name, dev_id);
1496                return !ret ? IRQC_IS_NESTED : ret;
1497        }
1498
1499        ret = request_irq(irq, handler, flags, name, dev_id);
1500        return !ret ? IRQC_IS_HARDIRQ : ret;
1501}
1502EXPORT_SYMBOL_GPL(request_any_context_irq);
1503
1504void enable_percpu_irq(unsigned int irq, unsigned int type)
1505{
1506        unsigned int cpu = smp_processor_id();
1507        unsigned long flags;
1508        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1509
1510        if (!desc)
1511                return;
1512
1513        type &= IRQ_TYPE_SENSE_MASK;
1514        if (type != IRQ_TYPE_NONE) {
1515                int ret;
1516
1517                ret = __irq_set_trigger(desc, irq, type);
1518
1519                if (ret) {
1520                        WARN(1, "failed to set type for IRQ%d\n", irq);
1521                        goto out;
1522                }
1523        }
1524
1525        irq_percpu_enable(desc, cpu);
1526out:
1527        irq_put_desc_unlock(desc, flags);
1528}
1529EXPORT_SYMBOL_GPL(enable_percpu_irq);
1530
1531void disable_percpu_irq(unsigned int irq)
1532{
1533        unsigned int cpu = smp_processor_id();
1534        unsigned long flags;
1535        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1536
1537        if (!desc)
1538                return;
1539
1540        irq_percpu_disable(desc, cpu);
1541        irq_put_desc_unlock(desc, flags);
1542}
1543EXPORT_SYMBOL_GPL(disable_percpu_irq);
1544
1545/*
1546 * Internal function to unregister a percpu irqaction.
1547 */
1548static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1549{
1550        struct irq_desc *desc = irq_to_desc(irq);
1551        struct irqaction *action;
1552        unsigned long flags;
1553
1554        WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1555
1556        if (!desc)
1557                return NULL;
1558
1559        raw_spin_lock_irqsave(&desc->lock, flags);
1560
1561        action = desc->action;
1562        if (!action || action->percpu_dev_id != dev_id) {
1563                WARN(1, "Trying to free already-free IRQ %d\n", irq);
1564                goto bad;
1565        }
1566
1567        if (!cpumask_empty(desc->percpu_enabled)) {
1568                WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1569                     irq, cpumask_first(desc->percpu_enabled));
1570                goto bad;
1571        }
1572
1573        /* Found it - now remove it from the list of entries: */
1574        desc->action = NULL;
1575
1576        raw_spin_unlock_irqrestore(&desc->lock, flags);
1577
1578        unregister_handler_proc(irq, action);
1579
1580        module_put(desc->owner);
1581        return action;
1582
1583bad:
1584        raw_spin_unlock_irqrestore(&desc->lock, flags);
1585        return NULL;
1586}
1587
1588/**
1589 *      remove_percpu_irq - free a per-cpu interrupt
1590 *      @irq: Interrupt line to free
1591 *      @act: irqaction for the interrupt
1592 *
1593 * Used to remove interrupts statically setup by the early boot process.
1594 */
1595void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1596{
1597        struct irq_desc *desc = irq_to_desc(irq);
1598
1599        if (desc && irq_settings_is_per_cpu_devid(desc))
1600            __free_percpu_irq(irq, act->percpu_dev_id);
1601}
1602
1603/**
1604 *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1605 *      @irq: Interrupt line to free
1606 *      @dev_id: Device identity to free
1607 *
1608 *      Remove a percpu interrupt handler. The handler is removed, but
1609 *      the interrupt line is not disabled. This must be done on each
1610 *      CPU before calling this function. The function does not return
1611 *      until any executing interrupts for this IRQ have completed.
1612 *
1613 *      This function must not be called from interrupt context.
1614 */
1615void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1616{
1617        struct irq_desc *desc = irq_to_desc(irq);
1618
1619        if (!desc || !irq_settings_is_per_cpu_devid(desc))
1620                return;
1621
1622        chip_bus_lock(desc);
1623        kfree(__free_percpu_irq(irq, dev_id));
1624        chip_bus_sync_unlock(desc);
1625}
1626
1627/**
1628 *      setup_percpu_irq - setup a per-cpu interrupt
1629 *      @irq: Interrupt line to setup
1630 *      @act: irqaction for the interrupt
1631 *
1632 * Used to statically setup per-cpu interrupts in the early boot process.
1633 */
1634int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1635{
1636        struct irq_desc *desc = irq_to_desc(irq);
1637        int retval;
1638
1639        if (!desc || !irq_settings_is_per_cpu_devid(desc))
1640                return -EINVAL;
1641        chip_bus_lock(desc);
1642        retval = __setup_irq(irq, desc, act);
1643        chip_bus_sync_unlock(desc);
1644
1645        return retval;
1646}
1647
1648/**
1649 *      request_percpu_irq - allocate a percpu interrupt line
1650 *      @irq: Interrupt line to allocate
1651 *      @handler: Function to be called when the IRQ occurs.
1652 *      @devname: An ascii name for the claiming device
1653 *      @dev_id: A percpu cookie passed back to the handler function
1654 *
1655 *      This call allocates interrupt resources, but doesn't
1656 *      automatically enable the interrupt. It has to be done on each
1657 *      CPU using enable_percpu_irq().
1658 *
1659 *      Dev_id must be globally unique. It is a per-cpu variable, and
1660 *      the handler gets called with the interrupted CPU's instance of
1661 *      that variable.
1662 */
1663int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1664                       const char *devname, void __percpu *dev_id)
1665{
1666        struct irqaction *action;
1667        struct irq_desc *desc;
1668        int retval;
1669
1670        if (!dev_id)
1671                return -EINVAL;
1672
1673        desc = irq_to_desc(irq);
1674        if (!desc || !irq_settings_can_request(desc) ||
1675            !irq_settings_is_per_cpu_devid(desc))
1676                return -EINVAL;
1677
1678        action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1679        if (!action)
1680                return -ENOMEM;
1681
1682        action->handler = handler;
1683        action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1684        action->name = devname;
1685        action->percpu_dev_id = dev_id;
1686
1687        chip_bus_lock(desc);
1688        retval = __setup_irq(irq, desc, action);
1689        chip_bus_sync_unlock(desc);
1690
1691        if (retval)
1692                kfree(action);
1693
1694        return retval;
1695}
1696
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