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, IRQ_GET_DESC_CHECK_GLOBAL);
 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, IRQ_GET_DESC_CHECK_GLOBAL);
 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, IRQ_GET_DESC_CHECK_GLOBAL);
 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 (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 471                 return 0;
 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, IRQ_GET_DESC_CHECK_GLOBAL);
 495         int ret = 0;
 496
 497         if (!desc)
 498                 return -EINVAL;
 499
 500         /* wakeup-capable irqs can be shared between drivers that
 501          * don't need to have the same sleep mode behaviors.
 502          */
 503         if (on) {
 504                 if (desc->wake_depth++ == 0) {
 505                         ret = set_irq_wake_real(irq, on);
 506                         if (ret)
 507                                 desc->wake_depth = 0;
 508                         else
 509                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 510                 }
 511         } else {
 512                 if (desc->wake_depth == 0) {
 513                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 514                 } else if (--desc->wake_depth == 0) {
 515                         ret = set_irq_wake_real(irq, on);
 516                         if (ret)
 517                                 desc->wake_depth = 1;
 518                         else
 519                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 520                 }
 521         }
 522         irq_put_desc_busunlock(desc, flags);
 523         return ret;
 524 }
 525 EXPORT_SYMBOL(irq_set_irq_wake);
 526
 527 /*
 528  * Internal function that tells the architecture code whether a
 529  * particular irq has been exclusively allocated or is available
 530  * for driver use.
 531  */
 532 int can_request_irq(unsigned int irq, unsigned long irqflags)
 533 {
 534         unsigned long flags;
 535         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 536         int canrequest = 0;
 537
 538         if (!desc)
 539                 return 0;
 540
 541         if (irq_settings_can_request(desc)) {
 542                 if (desc->action)
 543                         if (irqflags & desc->action->flags & IRQF_SHARED)
 544                                 canrequest =1;
 545         }
 546         irq_put_desc_unlock(desc, flags);
 547         return canrequest;
 548 }
 549
 550 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 551                       unsigned long flags)
 552 {
 553         struct irq_chip *chip = desc->irq_data.chip;
 554         int ret, unmask = 0;
 555
 556         if (!chip || !chip->irq_set_type) {
 557                 /*
 558                  * IRQF_TRIGGER_* but the PIC does not support multiple
 559                  * flow-types?
 560                  */
 561                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 562                                 chip ? (chip->name ? : "unknown") : "unknown");
 563                 return 0;
 564         }
 565
 566         flags &= IRQ_TYPE_SENSE_MASK;
 567
 568         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 569                 if (!irqd_irq_masked(&desc->irq_data))
 570                         mask_irq(desc);
 571                 if (!irqd_irq_disabled(&desc->irq_data))
 572                         unmask = 1;
 573         }
 574
 575         /* caller masked out all except trigger mode flags */
 576         ret = chip->irq_set_type(&desc->irq_data, flags);
 577
 578         switch (ret) {
 579         case IRQ_SET_MASK_OK:
 580                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 581                 irqd_set(&desc->irq_data, flags);
 582
 583         case IRQ_SET_MASK_OK_NOCOPY:
 584                 flags = irqd_get_trigger_type(&desc->irq_data);
 585                 irq_settings_set_trigger_mask(desc, flags);
 586                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 587                 irq_settings_clr_level(desc);
 588                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 589                         irq_settings_set_level(desc);
 590                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 591                 }
 592
 593                 ret = 0;
 594                 break;
 595         default:
 596                 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
 597                        flags, irq, chip->irq_set_type);
 598         }
 599         if (unmask)
 600                 unmask_irq(desc);
 601         return ret;
 602 }
 603
 604 /*
 605  * Default primary interrupt handler for threaded interrupts. Is
 606  * assigned as primary handler when request_threaded_irq is called
 607  * with handler == NULL. Useful for oneshot interrupts.
 608  */
 609 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 610 {
 611         return IRQ_WAKE_THREAD;
 612 }
 613
 614 /*
 615  * Primary handler for nested threaded interrupts. Should never be
 616  * called.
 617  */
 618 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 619 {
 620         WARN(1, "Primary handler called for nested irq %d\n", irq);
 621         return IRQ_NONE;
 622 }
 623
 624 static int irq_wait_for_interrupt(struct irqaction *action)
 625 {
 626         set_current_state(TASK_INTERRUPTIBLE);
 627
 628         while (!kthread_should_stop()) {
 629
 630                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 631                                        &action->thread_flags)) {
 632                         __set_current_state(TASK_RUNNING);
 633                         return 0;
 634                 }
 635                 schedule();
 636                 set_current_state(TASK_INTERRUPTIBLE);
 637         }
 638         __set_current_state(TASK_RUNNING);
 639         return -1;
 640 }
 641
 642 /*
 643  * Oneshot interrupts keep the irq line masked until the threaded
 644  * handler finished. unmask if the interrupt has not been disabled and
 645  * is marked MASKED.
 646  */
 647 static void irq_finalize_oneshot(struct irq_desc *desc,
 648                                  struct irqaction *action, bool force)
 649 {
 650         if (!(desc->istate & IRQS_ONESHOT))
 651                 return;
 652 again:
 653         chip_bus_lock(desc);
 654         raw_spin_lock_irq(&desc->lock);
 655
 656         /*
 657          * Implausible though it may be we need to protect us against
 658          * the following scenario:
 659          *
 660          * The thread is faster done than the hard interrupt handler
 661          * on the other CPU. If we unmask the irq line then the
 662          * interrupt can come in again and masks the line, leaves due
 663          * to IRQS_INPROGRESS and the irq line is masked forever.
 664          *
 665          * This also serializes the state of shared oneshot handlers
 666          * versus "desc->threads_onehsot |= action->thread_mask;" in
 667          * irq_wake_thread(). See the comment there which explains the
 668          * serialization.
 669          */
 670         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 671                 raw_spin_unlock_irq(&desc->lock);
 672                 chip_bus_sync_unlock(desc);
 673                 cpu_relax();
 674                 goto again;
 675         }
 676
 677         /*
 678          * Now check again, whether the thread should run. Otherwise
 679          * we would clear the threads_oneshot bit of this thread which
 680          * was just set.
 681          */
 682         if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 683                 goto out_unlock;
 684
 685         desc->threads_oneshot &= ~action->thread_mask;
 686
 687         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 688             irqd_irq_masked(&desc->irq_data))
 689                 unmask_irq(desc);
 690
 691 out_unlock:
 692         raw_spin_unlock_irq(&desc->lock);
 693         chip_bus_sync_unlock(desc);
 694 }
 695
 696 #ifdef CONFIG_SMP
 697 /*
 698  * Check whether we need to chasnge the affinity of the interrupt thread.
 699  */
 700 static void
 701 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 702 {
 703         cpumask_var_t mask;
 704
 705         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 706                 return;
 707
 708         /*
 709          * In case we are out of memory we set IRQTF_AFFINITY again and
 710          * try again next time
 711          */
 712         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 713                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 714                 return;
 715         }
 716
 717         raw_spin_lock_irq(&desc->lock);
 718         cpumask_copy(mask, desc->irq_data.affinity);
 719         raw_spin_unlock_irq(&desc->lock);
 720
 721         set_cpus_allowed_ptr(current, mask);
 722         free_cpumask_var(mask);
 723 }
 724 #else
 725 static inline void
 726 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 727 #endif
 728
 729 /*
 730  * Interrupts which are not explicitely requested as threaded
 731  * interrupts rely on the implicit bh/preempt disable of the hard irq
 732  * context. So we need to disable bh here to avoid deadlocks and other
 733  * side effects.
 734  */
 735 static irqreturn_t
 736 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 737 {
 738         irqreturn_t ret;
 739
 740         local_bh_disable();
 741         ret = action->thread_fn(action->irq, action->dev_id);
 742         irq_finalize_oneshot(desc, action, false);
 743         local_bh_enable();
 744         return ret;
 745 }
 746
 747 /*
 748  * Interrupts explicitely requested as threaded interupts want to be
 749  * preemtible - many of them need to sleep and wait for slow busses to
 750  * complete.
 751  */
 752 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 753                 struct irqaction *action)
 754 {
 755         irqreturn_t ret;
 756
 757         ret = action->thread_fn(action->irq, action->dev_id);
 758         irq_finalize_oneshot(desc, action, false);
 759         return ret;
 760 }
 761
 762 /*
 763  * Interrupt handler thread
 764  */
 765 static int irq_thread(void *data)
 766 {
 767         static const struct sched_param param = {
 768                 .sched_priority = MAX_USER_RT_PRIO/2,
 769         };
 770         struct irqaction *action = data;
 771         struct irq_desc *desc = irq_to_desc(action->irq);
 772         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 773                         struct irqaction *action);
 774         int wake;
 775
 776         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 777                                         &action->thread_flags))
 778                 handler_fn = irq_forced_thread_fn;
 779         else
 780                 handler_fn = irq_thread_fn;
 781
 782         sched_setscheduler(current, SCHED_FIFO, &param);
 783         current->irq_thread = 1;
 784
 785         while (!irq_wait_for_interrupt(action)) {
 786
 787                 irq_thread_check_affinity(desc, action);
 788
 789                 atomic_inc(&desc->threads_active);
 790
 791                 raw_spin_lock_irq(&desc->lock);
 792                 if (unlikely(irqd_irq_disabled(&desc->irq_data))) {
 793                         /*
 794                          * CHECKME: We might need a dedicated
 795                          * IRQ_THREAD_PENDING flag here, which
 796                          * retriggers the thread in check_irq_resend()
 797                          * but AFAICT IRQS_PENDING should be fine as it
 798                          * retriggers the interrupt itself --- tglx
 799                          */
 800                         desc->istate |= IRQS_PENDING;
 801                         raw_spin_unlock_irq(&desc->lock);
 802                 } else {
 803                         irqreturn_t action_ret;
 804
 805                         raw_spin_unlock_irq(&desc->lock);
 806                         action_ret = handler_fn(desc, action);
 807                         if (!noirqdebug)
 808                                 note_interrupt(action->irq, desc, action_ret);
 809                 }
 810
 811                 wake = atomic_dec_and_test(&desc->threads_active);
 812
 813                 if (wake && waitqueue_active(&desc->wait_for_threads))
 814                         wake_up(&desc->wait_for_threads);
 815         }
 816
 817         /* Prevent a stale desc->threads_oneshot */
 818         irq_finalize_oneshot(desc, action, true);
 819
 820         /*
 821          * Clear irq_thread. Otherwise exit_irq_thread() would make
 822          * fuzz about an active irq thread going into nirvana.
 823          */
 824         current->irq_thread = 0;
 825         return 0;
 826 }
 827
 828 /*
 829  * Called from do_exit()
 830  */
 831 void exit_irq_thread(void)
 832 {
 833         struct task_struct *tsk = current;
 834         struct irq_desc *desc;
 835         struct irqaction *action;
 836
 837         if (!tsk->irq_thread)
 838                 return;
 839
 840         action = kthread_data(tsk);
 841
 842         printk(KERN_ERR
 843                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 844                tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
 845
 846         desc = irq_to_desc(action->irq);
 847
 848         /*
 849          * Prevent a stale desc->threads_oneshot. Must be called
 850          * before setting the IRQTF_DIED flag.
 851          */
 852         irq_finalize_oneshot(desc, action, true);
 853
 854         /*
 855          * Set the THREAD DIED flag to prevent further wakeups of the
 856          * soon to be gone threaded handler.
 857          */
 858         set_bit(IRQTF_DIED, &action->flags);
 859 }
 860
 861 static void irq_setup_forced_threading(struct irqaction *new)
 862 {
 863         if (!force_irqthreads)
 864                 return;
 865         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 866                 return;
 867
 868         new->flags |= IRQF_ONESHOT;
 869
 870         if (!new->thread_fn) {
 871                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 872                 new->thread_fn = new->handler;
 873                 new->handler = irq_default_primary_handler;
 874         }
 875 }
 876
 877 /*
 878  * Internal function to register an irqaction - typically used to
 879  * allocate special interrupts that are part of the architecture.
 880  */
 881 static int
 882 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 883 {
 884         struct irqaction *old, **old_ptr;
 885         const char *old_name = NULL;
 886         unsigned long flags, thread_mask = 0;
 887         int ret, nested, shared = 0;
 888         cpumask_var_t mask;
 889
 890         if (!desc)
 891                 return -EINVAL;
 892
 893         if (desc->irq_data.chip == &no_irq_chip)
 894                 return -ENOSYS;
 895         if (!try_module_get(desc->owner))
 896                 return -ENODEV;
 897         /*
 898          * Some drivers like serial.c use request_irq() heavily,
 899          * so we have to be careful not to interfere with a
 900          * running system.
 901          */
 902         if (new->flags & IRQF_SAMPLE_RANDOM) {
 903                 /*
 904                  * This function might sleep, we want to call it first,
 905                  * outside of the atomic block.
 906                  * Yes, this might clear the entropy pool if the wrong
 907                  * driver is attempted to be loaded, without actually
 908                  * installing a new handler, but is this really a problem,
 909                  * only the sysadmin is able to do this.
 910                  */
 911                 rand_initialize_irq(irq);
 912         }
 913
 914         /*
 915          * Check whether the interrupt nests into another interrupt
 916          * thread.
 917          */
 918         nested = irq_settings_is_nested_thread(desc);
 919         if (nested) {
 920                 if (!new->thread_fn) {
 921                         ret = -EINVAL;
 922                         goto out_mput;
 923                 }
 924                 /*
 925                  * Replace the primary handler which was provided from
 926                  * the driver for non nested interrupt handling by the
 927                  * dummy function which warns when called.
 928                  */
 929                 new->handler = irq_nested_primary_handler;
 930         } else {
 931                 if (irq_settings_can_thread(desc))
 932                         irq_setup_forced_threading(new);
 933         }
 934
 935         /*
 936          * Create a handler thread when a thread function is supplied
 937          * and the interrupt does not nest into another interrupt
 938          * thread.
 939          */
 940         if (new->thread_fn && !nested) {
 941                 struct task_struct *t;
 942
 943                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 944                                    new->name);
 945                 if (IS_ERR(t)) {
 946                         ret = PTR_ERR(t);
 947                         goto out_mput;
 948                 }
 949                 /*
 950                  * We keep the reference to the task struct even if
 951                  * the thread dies to avoid that the interrupt code
 952                  * references an already freed task_struct.
 953                  */
 954                 get_task_struct(t);
 955                 new->thread = t;
 956         }
 957
 958         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 959                 ret = -ENOMEM;
 960                 goto out_thread;
 961         }
 962
 963         /*
 964          * The following block of code has to be executed atomically
 965          */
 966         raw_spin_lock_irqsave(&desc->lock, flags);
 967         old_ptr = &desc->action;
 968         old = *old_ptr;
 969         if (old) {
 970                 /*
 971                  * Can't share interrupts unless both agree to and are
 972                  * the same type (level, edge, polarity). So both flag
 973                  * fields must have IRQF_SHARED set and the bits which
 974                  * set the trigger type must match. Also all must
 975                  * agree on ONESHOT.
 976                  */
 977                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
 978                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
 979                     ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
 980                         old_name = old->name;
 981                         goto mismatch;
 982                 }
 983
 984                 /* All handlers must agree on per-cpuness */
 985                 if ((old->flags & IRQF_PERCPU) !=
 986                     (new->flags & IRQF_PERCPU))
 987                         goto mismatch;
 988
 989                 /* add new interrupt at end of irq queue */
 990                 do {
 991                         thread_mask |= old->thread_mask;
 992                         old_ptr = &old->next;
 993                         old = *old_ptr;
 994                 } while (old);
 995                 shared = 1;
 996         }
 997
 998         /*
 999          * Setup the thread mask for this irqaction. Unlikely to have
1000          * 32 resp 64 irqs sharing one line, but who knows.
1001          */
1002         if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
1003                 ret = -EBUSY;
1004                 goto out_mask;
1005         }
1006         new->thread_mask = 1 << ffz(thread_mask);
1007
1008         if (!shared) {
1009                 init_waitqueue_head(&desc->wait_for_threads);
1010
1011                 /* Setup the type (level, edge polarity) if configured: */
1012                 if (new->flags & IRQF_TRIGGER_MASK) {
1013                         ret = __irq_set_trigger(desc, irq,
1014                                         new->flags & IRQF_TRIGGER_MASK);
1015
1016                         if (ret)
1017                                 goto out_mask;
1018                 }
1019
1020                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1021                                   IRQS_ONESHOT | IRQS_WAITING);
1022                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1023
1024                 if (new->flags & IRQF_PERCPU) {
1025                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1026                         irq_settings_set_per_cpu(desc);
1027                 }
1028
1029                 if (new->flags & IRQF_ONESHOT)
1030                         desc->istate |= IRQS_ONESHOT;
1031
1032                 if (irq_settings_can_autoenable(desc))
1033                         irq_startup(desc);
1034                 else
1035                         /* Undo nested disables: */
1036                         desc->depth = 1;
1037
1038                 /* Exclude IRQ from balancing if requested */
1039                 if (new->flags & IRQF_NOBALANCING) {
1040                         irq_settings_set_no_balancing(desc);
1041                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1042                 }
1043
1044                 /* Set default affinity mask once everything is setup */
1045                 setup_affinity(irq, desc, mask);
1046
1047         } else if (new->flags & IRQF_TRIGGER_MASK) {
1048                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1049                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1050
1051                 if (nmsk != omsk)
1052                         /* hope the handler works with current  trigger mode */
1053                         pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1054                                    irq, nmsk, omsk);
1055         }
1056
1057         new->irq = irq;
1058         *old_ptr = new;
1059
1060         /* Reset broken irq detection when installing new handler */
1061         desc->irq_count = 0;
1062         desc->irqs_unhandled = 0;
1063
1064         /*
1065          * Check whether we disabled the irq via the spurious handler
1066          * before. Reenable it and give it another chance.
1067          */
1068         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1069                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1070                 __enable_irq(desc, irq, false);
1071         }
1072
1073         raw_spin_unlock_irqrestore(&desc->lock, flags);
1074
1075         /*
1076          * Strictly no need to wake it up, but hung_task complains
1077          * when no hard interrupt wakes the thread up.
1078          */
1079         if (new->thread)
1080                 wake_up_process(new->thread);
1081
1082         register_irq_proc(irq, desc);
1083         new->dir = NULL;
1084         register_handler_proc(irq, new);
1085         free_cpumask_var(mask);
1086
1087         return 0;
1088
1089 mismatch:
1090 #ifdef CONFIG_DEBUG_SHIRQ
1091         if (!(new->flags & IRQF_PROBE_SHARED)) {
1092                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
1093                 if (old_name)
1094                         printk(KERN_ERR "current handler: %s\n", old_name);
1095                 dump_stack();
1096         }
1097 #endif
1098         ret = -EBUSY;
1099
1100 out_mask:
1101         raw_spin_unlock_irqrestore(&desc->lock, flags);
1102         free_cpumask_var(mask);
1103
1104 out_thread:
1105         if (new->thread) {
1106                 struct task_struct *t = new->thread;
1107
1108                 new->thread = NULL;
1109                 kthread_stop(t);
1110                 put_task_struct(t);
1111         }
1112 out_mput:
1113         module_put(desc->owner);
1114         return ret;
1115 }
1116
1117 /**
1118  *      setup_irq - setup an interrupt
1119  *      @irq: Interrupt line to setup
1120  *      @act: irqaction for the interrupt
1121  *
1122  * Used to statically setup interrupts in the early boot process.
1123  */
1124 int setup_irq(unsigned int irq, struct irqaction *act)
1125 {
1126         int retval;
1127         struct irq_desc *desc = irq_to_desc(irq);
1128
1129         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1130                 return -EINVAL;
1131         chip_bus_lock(desc);
1132         retval = __setup_irq(irq, desc, act);
1133         chip_bus_sync_unlock(desc);
1134
1135         return retval;
1136 }
1137 EXPORT_SYMBOL_GPL(setup_irq);
1138
1139 /*
1140  * Internal function to unregister an irqaction - used to free
1141  * regular and special interrupts that are part of the architecture.
1142  */
1143 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1144 {
1145         struct irq_desc *desc = irq_to_desc(irq);
1146         struct irqaction *action, **action_ptr;
1147         unsigned long flags;
1148
1149         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1150
1151         if (!desc)
1152                 return NULL;
1153
1154         raw_spin_lock_irqsave(&desc->lock, flags);
1155
1156         /*
1157          * There can be multiple actions per IRQ descriptor, find the right
1158          * one based on the dev_id:
1159          */
1160         action_ptr = &desc->action;
1161         for (;;) {
1162                 action = *action_ptr;
1163
1164                 if (!action) {
1165                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1166                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1167
1168                         return NULL;
1169                 }
1170
1171                 if (action->dev_id == dev_id)
1172                         break;
1173                 action_ptr = &action->next;
1174         }
1175
1176         /* Found it - now remove it from the list of entries: */
1177         *action_ptr = action->next;
1178
1179         /* Currently used only by UML, might disappear one day: */
1180 #ifdef CONFIG_IRQ_RELEASE_METHOD
1181         if (desc->irq_data.chip->release)
1182                 desc->irq_data.chip->release(irq, dev_id);
1183 #endif
1184
1185         /* If this was the last handler, shut down the IRQ line: */
1186         if (!desc->action)
1187                 irq_shutdown(desc);
1188
1189 #ifdef CONFIG_SMP
1190         /* make sure affinity_hint is cleaned up */
1191         if (WARN_ON_ONCE(desc->affinity_hint))
1192                 desc->affinity_hint = NULL;
1193 #endif
1194
1195         raw_spin_unlock_irqrestore(&desc->lock, flags);
1196
1197         unregister_handler_proc(irq, action);
1198
1199         /* Make sure it's not being used on another CPU: */
1200         synchronize_irq(irq);
1201
1202 #ifdef CONFIG_DEBUG_SHIRQ
1203         /*
1204          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1205          * event to happen even now it's being freed, so let's make sure that
1206          * is so by doing an extra call to the handler ....
1207          *
1208          * ( We do this after actually deregistering it, to make sure that a
1209          *   'real' IRQ doesn't run in * parallel with our fake. )
1210          */
1211         if (action->flags & IRQF_SHARED) {
1212                 local_irq_save(flags);
1213                 action->handler(irq, dev_id);
1214                 local_irq_restore(flags);
1215         }
1216 #endif
1217
1218         if (action->thread) {
1219                 kthread_stop(action->thread);
1220                 put_task_struct(action->thread);
1221         }
1222
1223         module_put(desc->owner);
1224         return action;
1225 }
1226
1227 /**
1228  *      remove_irq - free an interrupt
1229  *      @irq: Interrupt line to free
1230  *      @act: irqaction for the interrupt
1231  *
1232  * Used to remove interrupts statically setup by the early boot process.
1233  */
1234 void remove_irq(unsigned int irq, struct irqaction *act)
1235 {
1236         struct irq_desc *desc = irq_to_desc(irq);
1237
1238         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1239             __free_irq(irq, act->dev_id);
1240 }
1241 EXPORT_SYMBOL_GPL(remove_irq);
1242
1243 /**
1244  *      free_irq - free an interrupt allocated with request_irq
1245  *      @irq: Interrupt line to free
1246  *      @dev_id: Device identity to free
1247  *
1248  *      Remove an interrupt handler. The handler is removed and if the
1249  *      interrupt line is no longer in use by any driver it is disabled.
1250  *      On a shared IRQ the caller must ensure the interrupt is disabled
1251  *      on the card it drives before calling this function. The function
1252  *      does not return until any executing interrupts for this IRQ
1253  *      have completed.
1254  *
1255  *      This function must not be called from interrupt context.
1256  */
1257 void free_irq(unsigned int irq, void *dev_id)
1258 {
1259         struct irq_desc *desc = irq_to_desc(irq);
1260
1261         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1262                 return;
1263
1264 #ifdef CONFIG_SMP
1265         if (WARN_ON(desc->affinity_notify))
1266                 desc->affinity_notify = NULL;
1267 #endif
1268
1269         chip_bus_lock(desc);
1270         kfree(__free_irq(irq, dev_id));
1271         chip_bus_sync_unlock(desc);
1272 }
1273 EXPORT_SYMBOL(free_irq);
1274
1275 /**
1276  *      request_threaded_irq - allocate an interrupt line
1277  *      @irq: Interrupt line to allocate
1278  *      @handler: Function to be called when the IRQ occurs.
1279  *                Primary handler for threaded interrupts
1280  *                If NULL and thread_fn != NULL the default
1281  *                primary handler is installed
1282  *      @thread_fn: Function called from the irq handler thread
1283  *                  If NULL, no irq thread is created
1284  *      @irqflags: Interrupt type flags
1285  *      @devname: An ascii name for the claiming device
1286  *      @dev_id: A cookie passed back to the handler function
1287  *
1288  *      This call allocates interrupt resources and enables the
1289  *      interrupt line and IRQ handling. From the point this
1290  *      call is made your handler function may be invoked. Since
1291  *      your handler function must clear any interrupt the board
1292  *      raises, you must take care both to initialise your hardware
1293  *      and to set up the interrupt handler in the right order.
1294  *
1295  *      If you want to set up a threaded irq handler for your device
1296  *      then you need to supply @handler and @thread_fn. @handler is
1297  *      still called in hard interrupt context and has to check
1298  *      whether the interrupt originates from the device. If yes it
1299  *      needs to disable the interrupt on the device and return
1300  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1301  *      @thread_fn. This split handler design is necessary to support
1302  *      shared interrupts.
1303  *
1304  *      Dev_id must be globally unique. Normally the address of the
1305  *      device data structure is used as the cookie. Since the handler
1306  *      receives this value it makes sense to use it.
1307  *
1308  *      If your interrupt is shared you must pass a non NULL dev_id
1309  *      as this is required when freeing the interrupt.
1310  *
1311  *      Flags:
1312  *
1313  *      IRQF_SHARED             Interrupt is shared
1314  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1315  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1316  *
1317  */
1318 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1319                          irq_handler_t thread_fn, unsigned long irqflags,
1320                          const char *devname, void *dev_id)
1321 {
1322         struct irqaction *action;
1323         struct irq_desc *desc;
1324         int retval;
1325
1326         /*
1327          * Sanity-check: shared interrupts must pass in a real dev-ID,
1328          * otherwise we'll have trouble later trying to figure out
1329          * which interrupt is which (messes up the interrupt freeing
1330          * logic etc).
1331          */
1332         if ((irqflags & IRQF_SHARED) && !dev_id)
1333                 return -EINVAL;
1334
1335         desc = irq_to_desc(irq);
1336         if (!desc)
1337                 return -EINVAL;
1338
1339         if (!irq_settings_can_request(desc) ||
1340             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1341                 return -EINVAL;
1342
1343         if (!handler) {
1344                 if (!thread_fn)
1345                         return -EINVAL;
1346                 handler = irq_default_primary_handler;
1347         }
1348
1349         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1350         if (!action)
1351                 return -ENOMEM;
1352
1353         action->handler = handler;
1354         action->thread_fn = thread_fn;
1355         action->flags = irqflags;
1356         action->name = devname;
1357         action->dev_id = dev_id;
1358
1359         chip_bus_lock(desc);
1360         retval = __setup_irq(irq, desc, action);
1361         chip_bus_sync_unlock(desc);
1362
1363         if (retval)
1364                 kfree(action);
1365
1366 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1367         if (!retval && (irqflags & IRQF_SHARED)) {
1368                 /*
1369                  * It's a shared IRQ -- the driver ought to be prepared for it
1370                  * to happen immediately, so let's make sure....
1371                  * We disable the irq to make sure that a 'real' IRQ doesn't
1372                  * run in parallel with our fake.
1373                  */
1374                 unsigned long flags;
1375
1376                 disable_irq(irq);
1377                 local_irq_save(flags);
1378
1379                 handler(irq, dev_id);
1380
1381                 local_irq_restore(flags);
1382                 enable_irq(irq);
1383         }
1384 #endif
1385         return retval;
1386 }
1387 EXPORT_SYMBOL(request_threaded_irq);
1388
1389 /**
1390  *      request_any_context_irq - allocate an interrupt line
1391  *      @irq: Interrupt line to allocate
1392  *      @handler: Function to be called when the IRQ occurs.
1393  *                Threaded handler for threaded interrupts.
1394  *      @flags: Interrupt type flags
1395  *      @name: An ascii name for the claiming device
1396  *      @dev_id: A cookie passed back to the handler function
1397  *
1398  *      This call allocates interrupt resources and enables the
1399  *      interrupt line and IRQ handling. It selects either a
1400  *      hardirq or threaded handling method depending on the
1401  *      context.
1402  *
1403  *      On failure, it returns a negative value. On success,
1404  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1405  */
1406 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1407                             unsigned long flags, const char *name, void *dev_id)
1408 {
1409         struct irq_desc *desc = irq_to_desc(irq);
1410         int ret;
1411
1412         if (!desc)
1413                 return -EINVAL;
1414
1415         if (irq_settings_is_nested_thread(desc)) {
1416                 ret = request_threaded_irq(irq, NULL, handler,
1417                                            flags, name, dev_id);
1418                 return !ret ? IRQC_IS_NESTED : ret;
1419         }
1420
1421         ret = request_irq(irq, handler, flags, name, dev_id);
1422         return !ret ? IRQC_IS_HARDIRQ : ret;
1423 }
1424 EXPORT_SYMBOL_GPL(request_any_context_irq);
1425
1426 void enable_percpu_irq(unsigned int irq, unsigned int type)
1427 {
1428         unsigned int cpu = smp_processor_id();
1429         unsigned long flags;
1430         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1431
1432         if (!desc)
1433                 return;
1434
1435         type &= IRQ_TYPE_SENSE_MASK;
1436         if (type != IRQ_TYPE_NONE) {
1437                 int ret;
1438
1439                 ret = __irq_set_trigger(desc, irq, type);
1440
1441                 if (ret) {
1442                         WARN(1, "failed to set type for IRQ%d\n", irq);
1443                         goto out;
1444                 }
1445         }
1446
1447         irq_percpu_enable(desc, cpu);
1448 out:
1449         irq_put_desc_unlock(desc, flags);
1450 }
1451
1452 void disable_percpu_irq(unsigned int irq)
1453 {
1454         unsigned int cpu = smp_processor_id();
1455         unsigned long flags;
1456         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1457
1458         if (!desc)
1459                 return;
1460
1461         irq_percpu_disable(desc, cpu);
1462         irq_put_desc_unlock(desc, flags);
1463 }
1464
1465 /*
1466  * Internal function to unregister a percpu irqaction.
1467  */
1468 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1469 {
1470         struct irq_desc *desc = irq_to_desc(irq);
1471         struct irqaction *action;
1472         unsigned long flags;
1473
1474         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1475
1476         if (!desc)
1477                 return NULL;
1478
1479         raw_spin_lock_irqsave(&desc->lock, flags);
1480
1481         action = desc->action;
1482         if (!action || action->percpu_dev_id != dev_id) {
1483                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1484                 goto bad;
1485         }
1486
1487         if (!cpumask_empty(desc->percpu_enabled)) {
1488                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1489                      irq, cpumask_first(desc->percpu_enabled));
1490                 goto bad;
1491         }
1492
1493         /* Found it - now remove it from the list of entries: */
1494         desc->action = NULL;
1495
1496         raw_spin_unlock_irqrestore(&desc->lock, flags);
1497
1498         unregister_handler_proc(irq, action);
1499
1500         module_put(desc->owner);
1501         return action;
1502
1503 bad:
1504         raw_spin_unlock_irqrestore(&desc->lock, flags);
1505         return NULL;
1506 }
1507
1508 /**
1509  *      remove_percpu_irq - free a per-cpu interrupt
1510  *      @irq: Interrupt line to free
1511  *      @act: irqaction for the interrupt
1512  *
1513  * Used to remove interrupts statically setup by the early boot process.
1514  */
1515 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1516 {
1517         struct irq_desc *desc = irq_to_desc(irq);
1518
1519         if (desc && irq_settings_is_per_cpu_devid(desc))
1520             __free_percpu_irq(irq, act->percpu_dev_id);
1521 }
1522
1523 /**
1524  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1525  *      @irq: Interrupt line to free
1526  *      @dev_id: Device identity to free
1527  *
1528  *      Remove a percpu interrupt handler. The handler is removed, but
1529  *      the interrupt line is not disabled. This must be done on each
1530  *      CPU before calling this function. The function does not return
1531  *      until any executing interrupts for this IRQ have completed.
1532  *
1533  *      This function must not be called from interrupt context.
1534  */
1535 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1536 {
1537         struct irq_desc *desc = irq_to_desc(irq);
1538
1539         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1540                 return;
1541
1542         chip_bus_lock(desc);
1543         kfree(__free_percpu_irq(irq, dev_id));
1544         chip_bus_sync_unlock(desc);
1545 }
1546
1547 /**
1548  *      setup_percpu_irq - setup a per-cpu interrupt
1549  *      @irq: Interrupt line to setup
1550  *      @act: irqaction for the interrupt
1551  *
1552  * Used to statically setup per-cpu interrupts in the early boot process.
1553  */
1554 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1555 {
1556         struct irq_desc *desc = irq_to_desc(irq);
1557         int retval;
1558
1559         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1560                 return -EINVAL;
1561         chip_bus_lock(desc);
1562         retval = __setup_irq(irq, desc, act);
1563         chip_bus_sync_unlock(desc);
1564
1565         return retval;
1566 }
1567
1568 /**
1569  *      request_percpu_irq - allocate a percpu interrupt line
1570  *      @irq: Interrupt line to allocate
1571  *      @handler: Function to be called when the IRQ occurs.
1572  *      @devname: An ascii name for the claiming device
1573  *      @dev_id: A percpu cookie passed back to the handler function
1574  *
1575  *      This call allocates interrupt resources, but doesn't
1576  *      automatically enable the interrupt. It has to be done on each
1577  *      CPU using enable_percpu_irq().
1578  *
1579  *      Dev_id must be globally unique. It is a per-cpu variable, and
1580  *      the handler gets called with the interrupted CPU's instance of
1581  *      that variable.
1582  */
1583 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1584                        const char *devname, void __percpu *dev_id)
1585 {
1586         struct irqaction *action;
1587         struct irq_desc *desc;
1588         int retval;
1589
1590         if (!dev_id)
1591                 return -EINVAL;
1592
1593         desc = irq_to_desc(irq);
1594         if (!desc || !irq_settings_can_request(desc) ||
1595             !irq_settings_is_per_cpu_devid(desc))
1596                 return -EINVAL;
1597
1598         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1599         if (!action)
1600                 return -ENOMEM;
1601
1602         action->handler = handler;
1603         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1604         action->name = devname;
1605         action->percpu_dev_id = dev_id;
1606
1607         chip_bus_lock(desc);
1608         retval = __setup_irq(irq, desc, action);
1609         chip_bus_sync_unlock(desc);
1610
1611         if (retval)
1612                 kfree(action);
1613
1614         return retval;
1615 }