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