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         /* Prevent a stale desc->threads_oneshot */
 849         irq_finalize_oneshot(desc, action, true);
 850 }
 851
 852 static void irq_setup_forced_threading(struct irqaction *new)
 853 {
 854         if (!force_irqthreads)
 855                 return;
 856         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 857                 return;
 858
 859         new->flags |= IRQF_ONESHOT;
 860
 861         if (!new->thread_fn) {
 862                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 863                 new->thread_fn = new->handler;
 864                 new->handler = irq_default_primary_handler;
 865         }
 866 }
 867
 868 /*
 869  * Internal function to register an irqaction - typically used to
 870  * allocate special interrupts that are part of the architecture.
 871  */
 872 static int
 873 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 874 {
 875         struct irqaction *old, **old_ptr;
 876         const char *old_name = NULL;
 877         unsigned long flags, thread_mask = 0;
 878         int ret, nested, shared = 0;
 879         cpumask_var_t mask;
 880
 881         if (!desc)
 882                 return -EINVAL;
 883
 884         if (desc->irq_data.chip == &no_irq_chip)
 885                 return -ENOSYS;
 886         if (!try_module_get(desc->owner))
 887                 return -ENODEV;
 888         /*
 889          * Some drivers like serial.c use request_irq() heavily,
 890          * so we have to be careful not to interfere with a
 891          * running system.
 892          */
 893         if (new->flags & IRQF_SAMPLE_RANDOM) {
 894                 /*
 895                  * This function might sleep, we want to call it first,
 896                  * outside of the atomic block.
 897                  * Yes, this might clear the entropy pool if the wrong
 898                  * driver is attempted to be loaded, without actually
 899                  * installing a new handler, but is this really a problem,
 900                  * only the sysadmin is able to do this.
 901                  */
 902                 rand_initialize_irq(irq);
 903         }
 904
 905         /*
 906          * Check whether the interrupt nests into another interrupt
 907          * thread.
 908          */
 909         nested = irq_settings_is_nested_thread(desc);
 910         if (nested) {
 911                 if (!new->thread_fn) {
 912                         ret = -EINVAL;
 913                         goto out_mput;
 914                 }
 915                 /*
 916                  * Replace the primary handler which was provided from
 917                  * the driver for non nested interrupt handling by the
 918                  * dummy function which warns when called.
 919                  */
 920                 new->handler = irq_nested_primary_handler;
 921         } else {
 922                 if (irq_settings_can_thread(desc))
 923                         irq_setup_forced_threading(new);
 924         }
 925
 926         /*
 927          * Create a handler thread when a thread function is supplied
 928          * and the interrupt does not nest into another interrupt
 929          * thread.
 930          */
 931         if (new->thread_fn && !nested) {
 932                 struct task_struct *t;
 933
 934                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 935                                    new->name);
 936                 if (IS_ERR(t)) {
 937                         ret = PTR_ERR(t);
 938                         goto out_mput;
 939                 }
 940                 /*
 941                  * We keep the reference to the task struct even if
 942                  * the thread dies to avoid that the interrupt code
 943                  * references an already freed task_struct.
 944                  */
 945                 get_task_struct(t);
 946                 new->thread = t;
 947         }
 948
 949         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 950                 ret = -ENOMEM;
 951                 goto out_thread;
 952         }
 953
 954         /*
 955          * The following block of code has to be executed atomically
 956          */
 957         raw_spin_lock_irqsave(&desc->lock, flags);
 958         old_ptr = &desc->action;
 959         old = *old_ptr;
 960         if (old) {
 961                 /*
 962                  * Can't share interrupts unless both agree to and are
 963                  * the same type (level, edge, polarity). So both flag
 964                  * fields must have IRQF_SHARED set and the bits which
 965                  * set the trigger type must match. Also all must
 966                  * agree on ONESHOT.
 967                  */
 968                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
 969                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
 970                     ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
 971                         old_name = old->name;
 972                         goto mismatch;
 973                 }
 974
 975                 /* All handlers must agree on per-cpuness */
 976                 if ((old->flags & IRQF_PERCPU) !=
 977                     (new->flags & IRQF_PERCPU))
 978                         goto mismatch;
 979
 980                 /* add new interrupt at end of irq queue */
 981                 do {
 982                         thread_mask |= old->thread_mask;
 983                         old_ptr = &old->next;
 984                         old = *old_ptr;
 985                 } while (old);
 986                 shared = 1;
 987         }
 988
 989         /*
 990          * Setup the thread mask for this irqaction. Unlikely to have
 991          * 32 resp 64 irqs sharing one line, but who knows.
 992          */
 993         if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) {
 994                 ret = -EBUSY;
 995                 goto out_mask;
 996         }
 997         new->thread_mask = 1 << ffz(thread_mask);
 998
 999         if (!shared) {
1000                 init_waitqueue_head(&desc->wait_for_threads);
1001
1002                 /* Setup the type (level, edge polarity) if configured: */
1003                 if (new->flags & IRQF_TRIGGER_MASK) {
1004                         ret = __irq_set_trigger(desc, irq,
1005                                         new->flags & IRQF_TRIGGER_MASK);
1006
1007                         if (ret)
1008                                 goto out_mask;
1009                 }
1010
1011                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1012                                   IRQS_ONESHOT | IRQS_WAITING);
1013                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1014
1015                 if (new->flags & IRQF_PERCPU) {
1016                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1017                         irq_settings_set_per_cpu(desc);
1018                 }
1019
1020                 if (new->flags & IRQF_ONESHOT)
1021                         desc->istate |= IRQS_ONESHOT;
1022
1023                 if (irq_settings_can_autoenable(desc))
1024                         irq_startup(desc);
1025                 else
1026                         /* Undo nested disables: */
1027                         desc->depth = 1;
1028
1029                 /* Exclude IRQ from balancing if requested */
1030                 if (new->flags & IRQF_NOBALANCING) {
1031                         irq_settings_set_no_balancing(desc);
1032                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1033                 }
1034
1035                 /* Set default affinity mask once everything is setup */
1036                 setup_affinity(irq, desc, mask);
1037
1038         } else if (new->flags & IRQF_TRIGGER_MASK) {
1039                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1040                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1041
1042                 if (nmsk != omsk)
1043                         /* hope the handler works with current  trigger mode */
1044                         pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1045                                    irq, nmsk, omsk);
1046         }
1047
1048         new->irq = irq;
1049         *old_ptr = new;
1050
1051         /* Reset broken irq detection when installing new handler */
1052         desc->irq_count = 0;
1053         desc->irqs_unhandled = 0;
1054
1055         /*
1056          * Check whether we disabled the irq via the spurious handler
1057          * before. Reenable it and give it another chance.
1058          */
1059         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1060                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1061                 __enable_irq(desc, irq, false);
1062         }
1063
1064         raw_spin_unlock_irqrestore(&desc->lock, flags);
1065
1066         /*
1067          * Strictly no need to wake it up, but hung_task complains
1068          * when no hard interrupt wakes the thread up.
1069          */
1070         if (new->thread)
1071                 wake_up_process(new->thread);
1072
1073         register_irq_proc(irq, desc);
1074         new->dir = NULL;
1075         register_handler_proc(irq, new);
1076         free_cpumask_var(mask);
1077
1078         return 0;
1079
1080 mismatch:
1081 #ifdef CONFIG_DEBUG_SHIRQ
1082         if (!(new->flags & IRQF_PROBE_SHARED)) {
1083                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
1084                 if (old_name)
1085                         printk(KERN_ERR "current handler: %s\n", old_name);
1086                 dump_stack();
1087         }
1088 #endif
1089         ret = -EBUSY;
1090
1091 out_mask:
1092         raw_spin_unlock_irqrestore(&desc->lock, flags);
1093         free_cpumask_var(mask);
1094
1095 out_thread:
1096         if (new->thread) {
1097                 struct task_struct *t = new->thread;
1098
1099                 new->thread = NULL;
1100                 kthread_stop(t);
1101                 put_task_struct(t);
1102         }
1103 out_mput:
1104         module_put(desc->owner);
1105         return ret;
1106 }
1107
1108 /**
1109  *      setup_irq - setup an interrupt
1110  *      @irq: Interrupt line to setup
1111  *      @act: irqaction for the interrupt
1112  *
1113  * Used to statically setup interrupts in the early boot process.
1114  */
1115 int setup_irq(unsigned int irq, struct irqaction *act)
1116 {
1117         int retval;
1118         struct irq_desc *desc = irq_to_desc(irq);
1119
1120         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1121                 return -EINVAL;
1122         chip_bus_lock(desc);
1123         retval = __setup_irq(irq, desc, act);
1124         chip_bus_sync_unlock(desc);
1125
1126         return retval;
1127 }
1128 EXPORT_SYMBOL_GPL(setup_irq);
1129
1130 /*
1131  * Internal function to unregister an irqaction - used to free
1132  * regular and special interrupts that are part of the architecture.
1133  */
1134 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1135 {
1136         struct irq_desc *desc = irq_to_desc(irq);
1137         struct irqaction *action, **action_ptr;
1138         unsigned long flags;
1139
1140         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1141
1142         if (!desc)
1143                 return NULL;
1144
1145         raw_spin_lock_irqsave(&desc->lock, flags);
1146
1147         /*
1148          * There can be multiple actions per IRQ descriptor, find the right
1149          * one based on the dev_id:
1150          */
1151         action_ptr = &desc->action;
1152         for (;;) {
1153                 action = *action_ptr;
1154
1155                 if (!action) {
1156                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1157                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1158
1159                         return NULL;
1160                 }
1161
1162                 if (action->dev_id == dev_id)
1163                         break;
1164                 action_ptr = &action->next;
1165         }
1166
1167         /* Found it - now remove it from the list of entries: */
1168         *action_ptr = action->next;
1169
1170         /* Currently used only by UML, might disappear one day: */
1171 #ifdef CONFIG_IRQ_RELEASE_METHOD
1172         if (desc->irq_data.chip->release)
1173                 desc->irq_data.chip->release(irq, dev_id);
1174 #endif
1175
1176         /* If this was the last handler, shut down the IRQ line: */
1177         if (!desc->action)
1178                 irq_shutdown(desc);
1179
1180 #ifdef CONFIG_SMP
1181         /* make sure affinity_hint is cleaned up */
1182         if (WARN_ON_ONCE(desc->affinity_hint))
1183                 desc->affinity_hint = NULL;
1184 #endif
1185
1186         raw_spin_unlock_irqrestore(&desc->lock, flags);
1187
1188         unregister_handler_proc(irq, action);
1189
1190         /* Make sure it's not being used on another CPU: */
1191         synchronize_irq(irq);
1192
1193 #ifdef CONFIG_DEBUG_SHIRQ
1194         /*
1195          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1196          * event to happen even now it's being freed, so let's make sure that
1197          * is so by doing an extra call to the handler ....
1198          *
1199          * ( We do this after actually deregistering it, to make sure that a
1200          *   'real' IRQ doesn't run in * parallel with our fake. )
1201          */
1202         if (action->flags & IRQF_SHARED) {
1203                 local_irq_save(flags);
1204                 action->handler(irq, dev_id);
1205                 local_irq_restore(flags);
1206         }
1207 #endif
1208
1209         if (action->thread) {
1210                 kthread_stop(action->thread);
1211                 put_task_struct(action->thread);
1212         }
1213
1214         module_put(desc->owner);
1215         return action;
1216 }
1217
1218 /**
1219  *      remove_irq - free an interrupt
1220  *      @irq: Interrupt line to free
1221  *      @act: irqaction for the interrupt
1222  *
1223  * Used to remove interrupts statically setup by the early boot process.
1224  */
1225 void remove_irq(unsigned int irq, struct irqaction *act)
1226 {
1227         struct irq_desc *desc = irq_to_desc(irq);
1228
1229         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1230             __free_irq(irq, act->dev_id);
1231 }
1232 EXPORT_SYMBOL_GPL(remove_irq);
1233
1234 /**
1235  *      free_irq - free an interrupt allocated with request_irq
1236  *      @irq: Interrupt line to free
1237  *      @dev_id: Device identity to free
1238  *
1239  *      Remove an interrupt handler. The handler is removed and if the
1240  *      interrupt line is no longer in use by any driver it is disabled.
1241  *      On a shared IRQ the caller must ensure the interrupt is disabled
1242  *      on the card it drives before calling this function. The function
1243  *      does not return until any executing interrupts for this IRQ
1244  *      have completed.
1245  *
1246  *      This function must not be called from interrupt context.
1247  */
1248 void free_irq(unsigned int irq, void *dev_id)
1249 {
1250         struct irq_desc *desc = irq_to_desc(irq);
1251
1252         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1253                 return;
1254
1255 #ifdef CONFIG_SMP
1256         if (WARN_ON(desc->affinity_notify))
1257                 desc->affinity_notify = NULL;
1258 #endif
1259
1260         chip_bus_lock(desc);
1261         kfree(__free_irq(irq, dev_id));
1262         chip_bus_sync_unlock(desc);
1263 }
1264 EXPORT_SYMBOL(free_irq);
1265
1266 /**
1267  *      request_threaded_irq - allocate an interrupt line
1268  *      @irq: Interrupt line to allocate
1269  *      @handler: Function to be called when the IRQ occurs.
1270  *                Primary handler for threaded interrupts
1271  *                If NULL and thread_fn != NULL the default
1272  *                primary handler is installed
1273  *      @thread_fn: Function called from the irq handler thread
1274  *                  If NULL, no irq thread is created
1275  *      @irqflags: Interrupt type flags
1276  *      @devname: An ascii name for the claiming device
1277  *      @dev_id: A cookie passed back to the handler function
1278  *
1279  *      This call allocates interrupt resources and enables the
1280  *      interrupt line and IRQ handling. From the point this
1281  *      call is made your handler function may be invoked. Since
1282  *      your handler function must clear any interrupt the board
1283  *      raises, you must take care both to initialise your hardware
1284  *      and to set up the interrupt handler in the right order.
1285  *
1286  *      If you want to set up a threaded irq handler for your device
1287  *      then you need to supply @handler and @thread_fn. @handler is
1288  *      still called in hard interrupt context and has to check
1289  *      whether the interrupt originates from the device. If yes it
1290  *      needs to disable the interrupt on the device and return
1291  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1292  *      @thread_fn. This split handler design is necessary to support
1293  *      shared interrupts.
1294  *
1295  *      Dev_id must be globally unique. Normally the address of the
1296  *      device data structure is used as the cookie. Since the handler
1297  *      receives this value it makes sense to use it.
1298  *
1299  *      If your interrupt is shared you must pass a non NULL dev_id
1300  *      as this is required when freeing the interrupt.
1301  *
1302  *      Flags:
1303  *
1304  *      IRQF_SHARED             Interrupt is shared
1305  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1306  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1307  *
1308  */
1309 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1310                          irq_handler_t thread_fn, unsigned long irqflags,
1311                          const char *devname, void *dev_id)
1312 {
1313         struct irqaction *action;
1314         struct irq_desc *desc;
1315         int retval;
1316
1317         /*
1318          * Sanity-check: shared interrupts must pass in a real dev-ID,
1319          * otherwise we'll have trouble later trying to figure out
1320          * which interrupt is which (messes up the interrupt freeing
1321          * logic etc).
1322          */
1323         if ((irqflags & IRQF_SHARED) && !dev_id)
1324                 return -EINVAL;
1325
1326         desc = irq_to_desc(irq);
1327         if (!desc)
1328                 return -EINVAL;
1329
1330         if (!irq_settings_can_request(desc) ||
1331             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1332                 return -EINVAL;
1333
1334         if (!handler) {
1335                 if (!thread_fn)
1336                         return -EINVAL;
1337                 handler = irq_default_primary_handler;
1338         }
1339
1340         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1341         if (!action)
1342                 return -ENOMEM;
1343
1344         action->handler = handler;
1345         action->thread_fn = thread_fn;
1346         action->flags = irqflags;
1347         action->name = devname;
1348         action->dev_id = dev_id;
1349
1350         chip_bus_lock(desc);
1351         retval = __setup_irq(irq, desc, action);
1352         chip_bus_sync_unlock(desc);
1353
1354         if (retval)
1355                 kfree(action);
1356
1357 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1358         if (!retval && (irqflags & IRQF_SHARED)) {
1359                 /*
1360                  * It's a shared IRQ -- the driver ought to be prepared for it
1361                  * to happen immediately, so let's make sure....
1362                  * We disable the irq to make sure that a 'real' IRQ doesn't
1363                  * run in parallel with our fake.
1364                  */
1365                 unsigned long flags;
1366
1367                 disable_irq(irq);
1368                 local_irq_save(flags);
1369
1370                 handler(irq, dev_id);
1371
1372                 local_irq_restore(flags);
1373                 enable_irq(irq);
1374         }
1375 #endif
1376         return retval;
1377 }
1378 EXPORT_SYMBOL(request_threaded_irq);
1379
1380 /**
1381  *      request_any_context_irq - allocate an interrupt line
1382  *      @irq: Interrupt line to allocate
1383  *      @handler: Function to be called when the IRQ occurs.
1384  *                Threaded handler for threaded interrupts.
1385  *      @flags: Interrupt type flags
1386  *      @name: An ascii name for the claiming device
1387  *      @dev_id: A cookie passed back to the handler function
1388  *
1389  *      This call allocates interrupt resources and enables the
1390  *      interrupt line and IRQ handling. It selects either a
1391  *      hardirq or threaded handling method depending on the
1392  *      context.
1393  *
1394  *      On failure, it returns a negative value. On success,
1395  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1396  */
1397 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1398                             unsigned long flags, const char *name, void *dev_id)
1399 {
1400         struct irq_desc *desc = irq_to_desc(irq);
1401         int ret;
1402
1403         if (!desc)
1404                 return -EINVAL;
1405
1406         if (irq_settings_is_nested_thread(desc)) {
1407                 ret = request_threaded_irq(irq, NULL, handler,
1408                                            flags, name, dev_id);
1409                 return !ret ? IRQC_IS_NESTED : ret;
1410         }
1411
1412         ret = request_irq(irq, handler, flags, name, dev_id);
1413         return !ret ? IRQC_IS_HARDIRQ : ret;
1414 }
1415 EXPORT_SYMBOL_GPL(request_any_context_irq);
1416
1417 void enable_percpu_irq(unsigned int irq, unsigned int type)
1418 {
1419         unsigned int cpu = smp_processor_id();
1420         unsigned long flags;
1421         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1422
1423         if (!desc)
1424                 return;
1425
1426         type &= IRQ_TYPE_SENSE_MASK;
1427         if (type != IRQ_TYPE_NONE) {
1428                 int ret;
1429
1430                 ret = __irq_set_trigger(desc, irq, type);
1431
1432                 if (ret) {
1433                         WARN(1, "failed to set type for IRQ%d\n", irq);
1434                         goto out;
1435                 }
1436         }
1437
1438         irq_percpu_enable(desc, cpu);
1439 out:
1440         irq_put_desc_unlock(desc, flags);
1441 }
1442
1443 void disable_percpu_irq(unsigned int irq)
1444 {
1445         unsigned int cpu = smp_processor_id();
1446         unsigned long flags;
1447         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1448
1449         if (!desc)
1450                 return;
1451
1452         irq_percpu_disable(desc, cpu);
1453         irq_put_desc_unlock(desc, flags);
1454 }
1455
1456 /*
1457  * Internal function to unregister a percpu irqaction.
1458  */
1459 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1460 {
1461         struct irq_desc *desc = irq_to_desc(irq);
1462         struct irqaction *action;
1463         unsigned long flags;
1464
1465         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1466
1467         if (!desc)
1468                 return NULL;
1469
1470         raw_spin_lock_irqsave(&desc->lock, flags);
1471
1472         action = desc->action;
1473         if (!action || action->percpu_dev_id != dev_id) {
1474                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1475                 goto bad;
1476         }
1477
1478         if (!cpumask_empty(desc->percpu_enabled)) {
1479                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1480                      irq, cpumask_first(desc->percpu_enabled));
1481                 goto bad;
1482         }
1483
1484         /* Found it - now remove it from the list of entries: */
1485         desc->action = NULL;
1486
1487         raw_spin_unlock_irqrestore(&desc->lock, flags);
1488
1489         unregister_handler_proc(irq, action);
1490
1491         module_put(desc->owner);
1492         return action;
1493
1494 bad:
1495         raw_spin_unlock_irqrestore(&desc->lock, flags);
1496         return NULL;
1497 }
1498
1499 /**
1500  *      remove_percpu_irq - free a per-cpu interrupt
1501  *      @irq: Interrupt line to free
1502  *      @act: irqaction for the interrupt
1503  *
1504  * Used to remove interrupts statically setup by the early boot process.
1505  */
1506 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1507 {
1508         struct irq_desc *desc = irq_to_desc(irq);
1509
1510         if (desc && irq_settings_is_per_cpu_devid(desc))
1511             __free_percpu_irq(irq, act->percpu_dev_id);
1512 }
1513
1514 /**
1515  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1516  *      @irq: Interrupt line to free
1517  *      @dev_id: Device identity to free
1518  *
1519  *      Remove a percpu interrupt handler. The handler is removed, but
1520  *      the interrupt line is not disabled. This must be done on each
1521  *      CPU before calling this function. The function does not return
1522  *      until any executing interrupts for this IRQ have completed.
1523  *
1524  *      This function must not be called from interrupt context.
1525  */
1526 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1527 {
1528         struct irq_desc *desc = irq_to_desc(irq);
1529
1530         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1531                 return;
1532
1533         chip_bus_lock(desc);
1534         kfree(__free_percpu_irq(irq, dev_id));
1535         chip_bus_sync_unlock(desc);
1536 }
1537
1538 /**
1539  *      setup_percpu_irq - setup a per-cpu interrupt
1540  *      @irq: Interrupt line to setup
1541  *      @act: irqaction for the interrupt
1542  *
1543  * Used to statically setup per-cpu interrupts in the early boot process.
1544  */
1545 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1546 {
1547         struct irq_desc *desc = irq_to_desc(irq);
1548         int retval;
1549
1550         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1551                 return -EINVAL;
1552         chip_bus_lock(desc);
1553         retval = __setup_irq(irq, desc, act);
1554         chip_bus_sync_unlock(desc);
1555
1556         return retval;
1557 }
1558
1559 /**
1560  *      request_percpu_irq - allocate a percpu interrupt line
1561  *      @irq: Interrupt line to allocate
1562  *      @handler: Function to be called when the IRQ occurs.
1563  *      @devname: An ascii name for the claiming device
1564  *      @dev_id: A percpu cookie passed back to the handler function
1565  *
1566  *      This call allocates interrupt resources, but doesn't
1567  *      automatically enable the interrupt. It has to be done on each
1568  *      CPU using enable_percpu_irq().
1569  *
1570  *      Dev_id must be globally unique. It is a per-cpu variable, and
1571  *      the handler gets called with the interrupted CPU's instance of
1572  *      that variable.
1573  */
1574 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1575                        const char *devname, void __percpu *dev_id)
1576 {
1577         struct irqaction *action;
1578         struct irq_desc *desc;
1579         int retval;
1580
1581         if (!dev_id)
1582                 return -EINVAL;
1583
1584         desc = irq_to_desc(irq);
1585         if (!desc || !irq_settings_can_request(desc) ||
1586             !irq_settings_is_per_cpu_devid(desc))
1587                 return -EINVAL;
1588
1589         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1590         if (!action)
1591                 return -ENOMEM;
1592
1593         action->handler = handler;
1594         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1595         action->name = devname;
1596         action->percpu_dev_id = dev_id;
1597
1598         chip_bus_lock(desc);
1599         retval = __setup_irq(irq, desc, action);
1600         chip_bus_sync_unlock(desc);
1601
1602         if (retval)
1603                 kfree(action);
1604
1605         return retval;
1606 }