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