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