kernel/irq/manage.c

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