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                     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         bool valid = true;
 705
 706         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 707                 return;
 708
 709         /*
 710          * In case we are out of memory we set IRQTF_AFFINITY again and
 711          * try again next time
 712          */
 713         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 714                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 715                 return;
 716         }
 717
 718         raw_spin_lock_irq(&desc->lock);
 719         /*
 720          * This code is triggered unconditionally. Check the affinity
 721          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 722          */
 723         if (desc->irq_data.affinity)
 724                 cpumask_copy(mask, desc->irq_data.affinity);
 725         else
 726                 valid = false;
 727         raw_spin_unlock_irq(&desc->lock);
 728
 729         if (valid)
 730                 set_cpus_allowed_ptr(current, mask);
 731         free_cpumask_var(mask);
 732 }
 733 #else
 734 static inline void
 735 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 736 #endif
 737
 738 /*
 739  * Interrupts which are not explicitely requested as threaded
 740  * interrupts rely on the implicit bh/preempt disable of the hard irq
 741  * context. So we need to disable bh here to avoid deadlocks and other
 742  * side effects.
 743  */
 744 static irqreturn_t
 745 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 746 {
 747         irqreturn_t ret;
 748
 749         local_bh_disable();
 750         ret = action->thread_fn(action->irq, action->dev_id);
 751         irq_finalize_oneshot(desc, action, false);
 752         local_bh_enable();
 753         return ret;
 754 }
 755
 756 /*
 757  * Interrupts explicitely requested as threaded interupts want to be
 758  * preemtible - many of them need to sleep and wait for slow busses to
 759  * complete.
 760  */
 761 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 762                 struct irqaction *action)
 763 {
 764         irqreturn_t ret;
 765
 766         ret = action->thread_fn(action->irq, action->dev_id);
 767         irq_finalize_oneshot(desc, action, false);
 768         return ret;
 769 }
 770
 771 /*
 772  * Interrupt handler thread
 773  */
 774 static int irq_thread(void *data)
 775 {
 776         static const struct sched_param param = {
 777                 .sched_priority = MAX_USER_RT_PRIO/2,
 778         };
 779         struct irqaction *action = data;
 780         struct irq_desc *desc = irq_to_desc(action->irq);
 781         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 782                         struct irqaction *action);
 783         int wake;
 784
 785         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 786                                         &action->thread_flags))
 787                 handler_fn = irq_forced_thread_fn;
 788         else
 789                 handler_fn = irq_thread_fn;
 790
 791         sched_setscheduler(current, SCHED_FIFO, &param);
 792         current->irqaction = action;
 793
 794         while (!irq_wait_for_interrupt(action)) {
 795
 796                 irq_thread_check_affinity(desc, action);
 797
 798                 atomic_inc(&desc->threads_active);
 799
 800                 raw_spin_lock_irq(&desc->lock);
 801                 if (unlikely(irqd_irq_disabled(&desc->irq_data))) {
 802                         /*
 803                          * CHECKME: We might need a dedicated
 804                          * IRQ_THREAD_PENDING flag here, which
 805                          * retriggers the thread in check_irq_resend()
 806                          * but AFAICT IRQS_PENDING should be fine as it
 807                          * retriggers the interrupt itself --- tglx
 808                          */
 809                         desc->istate |= IRQS_PENDING;
 810                         raw_spin_unlock_irq(&desc->lock);
 811                 } else {
 812                         irqreturn_t action_ret;
 813
 814                         raw_spin_unlock_irq(&desc->lock);
 815                         action_ret = handler_fn(desc, action);
 816                         if (action_ret == IRQ_HANDLED)
 817                                 atomic_inc(&desc->threads_handled);
 818                 }
 819
 820                 wake = atomic_dec_and_test(&desc->threads_active);
 821
 822                 if (wake)
 823                         wake_up(&desc->wait_for_threads);
 824         }
 825
 826         /* Prevent a stale desc->threads_oneshot */
 827         irq_finalize_oneshot(desc, action, true);
 828
 829         /*
 830          * Clear irqaction. Otherwise exit_irq_thread() would make
 831          * fuzz about an active irq thread going into nirvana.
 832          */
 833         current->irqaction = NULL;
 834         return 0;
 835 }
 836
 837 /*
 838  * Called from do_exit()
 839  */
 840 void exit_irq_thread(void)
 841 {
 842         struct task_struct *tsk = current;
 843         struct irq_desc *desc;
 844
 845         if (!tsk->irqaction)
 846                 return;
 847
 848         printk(KERN_ERR
 849                "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 850                tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
 851
 852         desc = irq_to_desc(tsk->irqaction->irq);
 853
 854         /*
 855          * Prevent a stale desc->threads_oneshot. Must be called
 856          * before setting the IRQTF_DIED flag.
 857          */
 858         irq_finalize_oneshot(desc, tsk->irqaction, true);
 859
 860         /*
 861          * Set the THREAD DIED flag to prevent further wakeups of the
 862          * soon to be gone threaded handler.
 863          */
 864         set_bit(IRQTF_DIED, &tsk->irqaction->flags);
 865 }
 866
 867 static void irq_setup_forced_threading(struct irqaction *new)
 868 {
 869         if (!force_irqthreads)
 870                 return;
 871         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 872                 return;
 873
 874         new->flags |= IRQF_ONESHOT;
 875
 876         if (!new->thread_fn) {
 877                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 878                 new->thread_fn = new->handler;
 879                 new->handler = irq_default_primary_handler;
 880         }
 881 }
 882
 883 /*
 884  * Internal function to register an irqaction - typically used to
 885  * allocate special interrupts that are part of the architecture.
 886  */
 887 static int
 888 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 889 {
 890         struct irqaction *old, **old_ptr;
 891         const char *old_name = NULL;
 892         unsigned long flags, thread_mask = 0;
 893         int ret, nested, shared = 0;
 894         cpumask_var_t mask;
 895
 896         if (!desc)
 897                 return -EINVAL;
 898
 899         if (desc->irq_data.chip == &no_irq_chip)
 900                 return -ENOSYS;
 901         if (!try_module_get(desc->owner))
 902                 return -ENODEV;
 903         /*
 904          * Some drivers like serial.c use request_irq() heavily,
 905          * so we have to be careful not to interfere with a
 906          * running system.
 907          */
 908         if (new->flags & IRQF_SAMPLE_RANDOM) {
 909                 /*
 910                  * This function might sleep, we want to call it first,
 911                  * outside of the atomic block.
 912                  * Yes, this might clear the entropy pool if the wrong
 913                  * driver is attempted to be loaded, without actually
 914                  * installing a new handler, but is this really a problem,
 915                  * only the sysadmin is able to do this.
 916                  */
 917                 rand_initialize_irq(irq);
 918         }
 919
 920         /*
 921          * Check whether the interrupt nests into another interrupt
 922          * thread.
 923          */
 924         nested = irq_settings_is_nested_thread(desc);
 925         if (nested) {
 926                 if (!new->thread_fn) {
 927                         ret = -EINVAL;
 928                         goto out_mput;
 929                 }
 930                 /*
 931                  * Replace the primary handler which was provided from
 932                  * the driver for non nested interrupt handling by the
 933                  * dummy function which warns when called.
 934                  */
 935                 new->handler = irq_nested_primary_handler;
 936         } else {
 937                 if (irq_settings_can_thread(desc))
 938                         irq_setup_forced_threading(new);
 939         }
 940
 941         /*
 942          * Create a handler thread when a thread function is supplied
 943          * and the interrupt does not nest into another interrupt
 944          * thread.
 945          */
 946         if (new->thread_fn && !nested) {
 947                 struct task_struct *t;
 948
 949                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 950                                    new->name);
 951                 if (IS_ERR(t)) {
 952                         ret = PTR_ERR(t);
 953                         goto out_mput;
 954                 }
 955                 /*
 956                  * We keep the reference to the task struct even if
 957                  * the thread dies to avoid that the interrupt code
 958                  * references an already freed task_struct.
 959                  */
 960                 get_task_struct(t);
 961                 new->thread = t;
 962                 /*
 963                  * Tell the thread to set its affinity. This is
 964                  * important for shared interrupt handlers as we do
 965                  * not invoke setup_affinity() for the secondary
 966                  * handlers as everything is already set up. Even for
 967                  * interrupts marked with IRQF_NO_BALANCE this is
 968                  * correct as we want the thread to move to the cpu(s)
 969                  * on which the requesting code placed the interrupt.
 970                  */
 971                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
 972         }
 973
 974         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 975                 ret = -ENOMEM;
 976                 goto out_thread;
 977         }
 978
 979         /*
 980          * The following block of code has to be executed atomically
 981          */
 982         raw_spin_lock_irqsave(&desc->lock, flags);
 983         old_ptr = &desc->action;
 984         old = *old_ptr;
 985         if (old) {
 986                 /*
 987                  * Can't share interrupts unless both agree to and are
 988                  * the same type (level, edge, polarity). So both flag
 989                  * fields must have IRQF_SHARED set and the bits which
 990                  * set the trigger type must match. Also all must
 991                  * agree on ONESHOT.
 992                  */
 993                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
 994                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
 995                     ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
 996                         old_name = old->name;
 997                         goto mismatch;
 998                 }
 999
1000                 /* All handlers must agree on per-cpuness */
1001                 if ((old->flags & IRQF_PERCPU) !=
1002                     (new->flags & IRQF_PERCPU))
1003                         goto mismatch;
1004
1005                 /* add new interrupt at end of irq queue */
1006                 do {
1007                         /*
1008                          * Or all existing action->thread_mask bits,
1009                          * so we can find the next zero bit for this
1010                          * new action.
1011                          */
1012                         thread_mask |= old->thread_mask;
1013                         old_ptr = &old->next;
1014                         old = *old_ptr;
1015                 } while (old);
1016                 shared = 1;
1017         }
1018
1019         /*
1020          * Setup the thread mask for this irqaction for ONESHOT. For
1021          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1022          * conditional in irq_wake_thread().
1023          */
1024         if (new->flags & IRQF_ONESHOT) {
1025                 /*
1026                  * Unlikely to have 32 resp 64 irqs sharing one line,
1027                  * but who knows.
1028                  */
1029                 if (thread_mask == ~0UL) {
1030                         ret = -EBUSY;
1031                         goto out_mask;
1032                 }
1033                 /*
1034                  * The thread_mask for the action is or'ed to
1035                  * desc->thread_active to indicate that the
1036                  * IRQF_ONESHOT thread handler has been woken, but not
1037                  * yet finished. The bit is cleared when a thread
1038                  * completes. When all threads of a shared interrupt
1039                  * line have completed desc->threads_active becomes
1040                  * zero and the interrupt line is unmasked. See
1041                  * handle.c:irq_wake_thread() for further information.
1042                  *
1043                  * If no thread is woken by primary (hard irq context)
1044                  * interrupt handlers, then desc->threads_active is
1045                  * also checked for zero to unmask the irq line in the
1046                  * affected hard irq flow handlers
1047                  * (handle_[fasteoi|level]_irq).
1048                  *
1049                  * The new action gets the first zero bit of
1050                  * thread_mask assigned. See the loop above which or's
1051                  * all existing action->thread_mask bits.
1052                  */
1053                 new->thread_mask = 1 << ffz(thread_mask);
1054         }
1055
1056         if (!shared) {
1057                 init_waitqueue_head(&desc->wait_for_threads);
1058
1059                 /* Setup the type (level, edge polarity) if configured: */
1060                 if (new->flags & IRQF_TRIGGER_MASK) {
1061                         ret = __irq_set_trigger(desc, irq,
1062                                         new->flags & IRQF_TRIGGER_MASK);
1063
1064                         if (ret)
1065                                 goto out_mask;
1066                 }
1067
1068                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1069                                   IRQS_ONESHOT | IRQS_WAITING);
1070                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1071
1072                 if (new->flags & IRQF_PERCPU) {
1073                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1074                         irq_settings_set_per_cpu(desc);
1075                 }
1076
1077                 if (new->flags & IRQF_ONESHOT)
1078                         desc->istate |= IRQS_ONESHOT;
1079
1080                 if (irq_settings_can_autoenable(desc))
1081                         irq_startup(desc, true);
1082                 else
1083                         /* Undo nested disables: */
1084                         desc->depth = 1;
1085
1086                 /* Exclude IRQ from balancing if requested */
1087                 if (new->flags & IRQF_NOBALANCING) {
1088                         irq_settings_set_no_balancing(desc);
1089                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1090                 }
1091
1092                 /* Set default affinity mask once everything is setup */
1093                 setup_affinity(irq, desc, mask);
1094
1095         } else if (new->flags & IRQF_TRIGGER_MASK) {
1096                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1097                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1098
1099                 if (nmsk != omsk)
1100                         /* hope the handler works with current  trigger mode */
1101                         pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1102                                    irq, nmsk, omsk);
1103         }
1104
1105         new->irq = irq;
1106         *old_ptr = new;
1107
1108         /* Reset broken irq detection when installing new handler */
1109         desc->irq_count = 0;
1110         desc->irqs_unhandled = 0;
1111
1112         /*
1113          * Check whether we disabled the irq via the spurious handler
1114          * before. Reenable it and give it another chance.
1115          */
1116         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1117                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1118                 __enable_irq(desc, irq, false);
1119         }
1120
1121         raw_spin_unlock_irqrestore(&desc->lock, flags);
1122
1123         /*
1124          * Strictly no need to wake it up, but hung_task complains
1125          * when no hard interrupt wakes the thread up.
1126          */
1127         if (new->thread)
1128                 wake_up_process(new->thread);
1129
1130         register_irq_proc(irq, desc);
1131         new->dir = NULL;
1132         register_handler_proc(irq, new);
1133         free_cpumask_var(mask);
1134
1135         return 0;
1136
1137 mismatch:
1138 #ifdef CONFIG_DEBUG_SHIRQ
1139         if (!(new->flags & IRQF_PROBE_SHARED)) {
1140                 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
1141                 if (old_name)
1142                         printk(KERN_ERR "current handler: %s\n", old_name);
1143                 dump_stack();
1144         }
1145 #endif
1146         ret = -EBUSY;
1147
1148 out_mask:
1149         raw_spin_unlock_irqrestore(&desc->lock, flags);
1150         free_cpumask_var(mask);
1151
1152 out_thread:
1153         if (new->thread) {
1154                 struct task_struct *t = new->thread;
1155
1156                 new->thread = NULL;
1157                 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
1158                         kthread_stop(t);
1159                 put_task_struct(t);
1160         }
1161 out_mput:
1162         module_put(desc->owner);
1163         return ret;
1164 }
1165
1166 /**
1167  *      setup_irq - setup an interrupt
1168  *      @irq: Interrupt line to setup
1169  *      @act: irqaction for the interrupt
1170  *
1171  * Used to statically setup interrupts in the early boot process.
1172  */
1173 int setup_irq(unsigned int irq, struct irqaction *act)
1174 {
1175         int retval;
1176         struct irq_desc *desc = irq_to_desc(irq);
1177
1178         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1179                 return -EINVAL;
1180         chip_bus_lock(desc);
1181         retval = __setup_irq(irq, desc, act);
1182         chip_bus_sync_unlock(desc);
1183
1184         return retval;
1185 }
1186 EXPORT_SYMBOL_GPL(setup_irq);
1187
1188 /*
1189  * Internal function to unregister an irqaction - used to free
1190  * regular and special interrupts that are part of the architecture.
1191  */
1192 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1193 {
1194         struct irq_desc *desc = irq_to_desc(irq);
1195         struct irqaction *action, **action_ptr;
1196         unsigned long flags;
1197
1198         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1199
1200         if (!desc)
1201                 return NULL;
1202
1203         chip_bus_lock(desc);
1204         raw_spin_lock_irqsave(&desc->lock, flags);
1205
1206         /*
1207          * There can be multiple actions per IRQ descriptor, find the right
1208          * one based on the dev_id:
1209          */
1210         action_ptr = &desc->action;
1211         for (;;) {
1212                 action = *action_ptr;
1213
1214                 if (!action) {
1215                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1216                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1217                         chip_bus_sync_unlock(desc);
1218                         return NULL;
1219                 }
1220
1221                 if (action->dev_id == dev_id)
1222                         break;
1223                 action_ptr = &action->next;
1224         }
1225
1226         /* Found it - now remove it from the list of entries: */
1227         *action_ptr = action->next;
1228
1229         /* Currently used only by UML, might disappear one day: */
1230 #ifdef CONFIG_IRQ_RELEASE_METHOD
1231         if (desc->irq_data.chip->release)
1232                 desc->irq_data.chip->release(irq, dev_id);
1233 #endif
1234
1235         /* If this was the last handler, shut down the IRQ line: */
1236         if (!desc->action)
1237                 irq_shutdown(desc);
1238
1239 #ifdef CONFIG_SMP
1240         /* make sure affinity_hint is cleaned up */
1241         if (WARN_ON_ONCE(desc->affinity_hint))
1242                 desc->affinity_hint = NULL;
1243 #endif
1244
1245         raw_spin_unlock_irqrestore(&desc->lock, flags);
1246         chip_bus_sync_unlock(desc);
1247
1248         unregister_handler_proc(irq, action);
1249
1250         /* Make sure it's not being used on another CPU: */
1251         synchronize_irq(irq);
1252
1253 #ifdef CONFIG_DEBUG_SHIRQ
1254         /*
1255          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1256          * event to happen even now it's being freed, so let's make sure that
1257          * is so by doing an extra call to the handler ....
1258          *
1259          * ( We do this after actually deregistering it, to make sure that a
1260          *   'real' IRQ doesn't run in * parallel with our fake. )
1261          */
1262         if (action->flags & IRQF_SHARED) {
1263                 local_irq_save(flags);
1264                 action->handler(irq, dev_id);
1265                 local_irq_restore(flags);
1266         }
1267 #endif
1268
1269         if (action->thread) {
1270                 if (!test_bit(IRQTF_DIED, &action->thread_flags))
1271                         kthread_stop(action->thread);
1272                 put_task_struct(action->thread);
1273         }
1274
1275         module_put(desc->owner);
1276         return action;
1277 }
1278
1279 /**
1280  *      remove_irq - free an interrupt
1281  *      @irq: Interrupt line to free
1282  *      @act: irqaction for the interrupt
1283  *
1284  * Used to remove interrupts statically setup by the early boot process.
1285  */
1286 void remove_irq(unsigned int irq, struct irqaction *act)
1287 {
1288         struct irq_desc *desc = irq_to_desc(irq);
1289
1290         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1291             __free_irq(irq, act->dev_id);
1292 }
1293 EXPORT_SYMBOL_GPL(remove_irq);
1294
1295 /**
1296  *      free_irq - free an interrupt allocated with request_irq
1297  *      @irq: Interrupt line to free
1298  *      @dev_id: Device identity to free
1299  *
1300  *      Remove an interrupt handler. The handler is removed and if the
1301  *      interrupt line is no longer in use by any driver it is disabled.
1302  *      On a shared IRQ the caller must ensure the interrupt is disabled
1303  *      on the card it drives before calling this function. The function
1304  *      does not return until any executing interrupts for this IRQ
1305  *      have completed.
1306  *
1307  *      This function must not be called from interrupt context.
1308  */
1309 void free_irq(unsigned int irq, void *dev_id)
1310 {
1311         struct irq_desc *desc = irq_to_desc(irq);
1312
1313         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1314                 return;
1315
1316 #ifdef CONFIG_SMP
1317         if (WARN_ON(desc->affinity_notify))
1318                 desc->affinity_notify = NULL;
1319 #endif
1320
1321         kfree(__free_irq(irq, dev_id));
1322 }
1323 EXPORT_SYMBOL(free_irq);
1324
1325 /**
1326  *      request_threaded_irq - allocate an interrupt line
1327  *      @irq: Interrupt line to allocate
1328  *      @handler: Function to be called when the IRQ occurs.
1329  *                Primary handler for threaded interrupts
1330  *                If NULL and thread_fn != NULL the default
1331  *                primary handler is installed
1332  *      @thread_fn: Function called from the irq handler thread
1333  *                  If NULL, no irq thread is created
1334  *      @irqflags: Interrupt type flags
1335  *      @devname: An ascii name for the claiming device
1336  *      @dev_id: A cookie passed back to the handler function
1337  *
1338  *      This call allocates interrupt resources and enables the
1339  *      interrupt line and IRQ handling. From the point this
1340  *      call is made your handler function may be invoked. Since
1341  *      your handler function must clear any interrupt the board
1342  *      raises, you must take care both to initialise your hardware
1343  *      and to set up the interrupt handler in the right order.
1344  *
1345  *      If you want to set up a threaded irq handler for your device
1346  *      then you need to supply @handler and @thread_fn. @handler ist
1347  *      still called in hard interrupt context and has to check
1348  *      whether the interrupt originates from the device. If yes it
1349  *      needs to disable the interrupt on the device and return
1350  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1351  *      @thread_fn. This split handler design is necessary to support
1352  *      shared interrupts.
1353  *
1354  *      Dev_id must be globally unique. Normally the address of the
1355  *      device data structure is used as the cookie. Since the handler
1356  *      receives this value it makes sense to use it.
1357  *
1358  *      If your interrupt is shared you must pass a non NULL dev_id
1359  *      as this is required when freeing the interrupt.
1360  *
1361  *      Flags:
1362  *
1363  *      IRQF_SHARED             Interrupt is shared
1364  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1365  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1366  *
1367  */
1368 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1369                          irq_handler_t thread_fn, unsigned long irqflags,
1370                          const char *devname, void *dev_id)
1371 {
1372         struct irqaction *action;
1373         struct irq_desc *desc;
1374         int retval;
1375
1376         /*
1377          * Sanity-check: shared interrupts must pass in a real dev-ID,
1378          * otherwise we'll have trouble later trying to figure out
1379          * which interrupt is which (messes up the interrupt freeing
1380          * logic etc).
1381          */
1382         if ((irqflags & IRQF_SHARED) && !dev_id)
1383                 return -EINVAL;
1384
1385         desc = irq_to_desc(irq);
1386         if (!desc)
1387                 return -EINVAL;
1388
1389         if (!irq_settings_can_request(desc) ||
1390             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1391                 return -EINVAL;
1392
1393         if (!handler) {
1394                 if (!thread_fn)
1395                         return -EINVAL;
1396                 handler = irq_default_primary_handler;
1397         }
1398
1399         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1400         if (!action)
1401                 return -ENOMEM;
1402
1403         action->handler = handler;
1404         action->thread_fn = thread_fn;
1405         action->flags = irqflags;
1406         action->name = devname;
1407         action->dev_id = dev_id;
1408
1409         chip_bus_lock(desc);
1410         retval = __setup_irq(irq, desc, action);
1411         chip_bus_sync_unlock(desc);
1412
1413         if (retval)
1414                 kfree(action);
1415
1416 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1417         if (!retval && (irqflags & IRQF_SHARED)) {
1418                 /*
1419                  * It's a shared IRQ -- the driver ought to be prepared for it
1420                  * to happen immediately, so let's make sure....
1421                  * We disable the irq to make sure that a 'real' IRQ doesn't
1422                  * run in parallel with our fake.
1423                  */
1424                 unsigned long flags;
1425
1426                 disable_irq(irq);
1427                 local_irq_save(flags);
1428
1429                 handler(irq, dev_id);
1430
1431                 local_irq_restore(flags);
1432                 enable_irq(irq);
1433         }
1434 #endif
1435         return retval;
1436 }
1437 EXPORT_SYMBOL(request_threaded_irq);
1438
1439 /**
1440  *      request_any_context_irq - allocate an interrupt line
1441  *      @irq: Interrupt line to allocate
1442  *      @handler: Function to be called when the IRQ occurs.
1443  *                Threaded handler for threaded interrupts.
1444  *      @flags: Interrupt type flags
1445  *      @name: An ascii name for the claiming device
1446  *      @dev_id: A cookie passed back to the handler function
1447  *
1448  *      This call allocates interrupt resources and enables the
1449  *      interrupt line and IRQ handling. It selects either a
1450  *      hardirq or threaded handling method depending on the
1451  *      context.
1452  *
1453  *      On failure, it returns a negative value. On success,
1454  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1455  */
1456 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1457                             unsigned long flags, const char *name, void *dev_id)
1458 {
1459         struct irq_desc *desc = irq_to_desc(irq);
1460         int ret;
1461
1462         if (!desc)
1463                 return -EINVAL;
1464
1465         if (irq_settings_is_nested_thread(desc)) {
1466                 ret = request_threaded_irq(irq, NULL, handler,
1467                                            flags, name, dev_id);
1468                 return !ret ? IRQC_IS_NESTED : ret;
1469         }
1470
1471         ret = request_irq(irq, handler, flags, name, dev_id);
1472         return !ret ? IRQC_IS_HARDIRQ : ret;
1473 }
1474 EXPORT_SYMBOL_GPL(request_any_context_irq);
1475
1476 void enable_percpu_irq(unsigned int irq, unsigned int type)
1477 {
1478         unsigned int cpu = smp_processor_id();
1479         unsigned long flags;
1480         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1481
1482         if (!desc)
1483                 return;
1484
1485         type &= IRQ_TYPE_SENSE_MASK;
1486         if (type != IRQ_TYPE_NONE) {
1487                 int ret;
1488
1489                 ret = __irq_set_trigger(desc, irq, type);
1490
1491                 if (ret) {
1492                         WARN(1, "failed to set type for IRQ%d\n", irq);
1493                         goto out;
1494                 }
1495         }
1496
1497         irq_percpu_enable(desc, cpu);
1498 out:
1499         irq_put_desc_unlock(desc, flags);
1500 }
1501
1502 void disable_percpu_irq(unsigned int irq)
1503 {
1504         unsigned int cpu = smp_processor_id();
1505         unsigned long flags;
1506         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1507
1508         if (!desc)
1509                 return;
1510
1511         irq_percpu_disable(desc, cpu);
1512         irq_put_desc_unlock(desc, flags);
1513 }
1514
1515 /*
1516  * Internal function to unregister a percpu irqaction.
1517  */
1518 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1519 {
1520         struct irq_desc *desc = irq_to_desc(irq);
1521         struct irqaction *action;
1522         unsigned long flags;
1523
1524         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1525
1526         if (!desc)
1527                 return NULL;
1528
1529         raw_spin_lock_irqsave(&desc->lock, flags);
1530
1531         action = desc->action;
1532         if (!action || action->percpu_dev_id != dev_id) {
1533                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1534                 goto bad;
1535         }
1536
1537         if (!cpumask_empty(desc->percpu_enabled)) {
1538                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1539                      irq, cpumask_first(desc->percpu_enabled));
1540                 goto bad;
1541         }
1542
1543         /* Found it - now remove it from the list of entries: */
1544         desc->action = NULL;
1545
1546         raw_spin_unlock_irqrestore(&desc->lock, flags);
1547
1548         unregister_handler_proc(irq, action);
1549
1550         module_put(desc->owner);
1551         return action;
1552
1553 bad:
1554         raw_spin_unlock_irqrestore(&desc->lock, flags);
1555         return NULL;
1556 }
1557
1558 /**
1559  *      remove_percpu_irq - free a per-cpu interrupt
1560  *      @irq: Interrupt line to free
1561  *      @act: irqaction for the interrupt
1562  *
1563  * Used to remove interrupts statically setup by the early boot process.
1564  */
1565 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1566 {
1567         struct irq_desc *desc = irq_to_desc(irq);
1568
1569         if (desc && irq_settings_is_per_cpu_devid(desc))
1570             __free_percpu_irq(irq, act->percpu_dev_id);
1571 }
1572
1573 /**
1574  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1575  *      @irq: Interrupt line to free
1576  *      @dev_id: Device identity to free
1577  *
1578  *      Remove a percpu interrupt handler. The handler is removed, but
1579  *      the interrupt line is not disabled. This must be done on each
1580  *      CPU before calling this function. The function does not return
1581  *      until any executing interrupts for this IRQ have completed.
1582  *
1583  *      This function must not be called from interrupt context.
1584  */
1585 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1586 {
1587         struct irq_desc *desc = irq_to_desc(irq);
1588
1589         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1590                 return;
1591
1592         chip_bus_lock(desc);
1593         kfree(__free_percpu_irq(irq, dev_id));
1594         chip_bus_sync_unlock(desc);
1595 }
1596
1597 /**
1598  *      setup_percpu_irq - setup a per-cpu interrupt
1599  *      @irq: Interrupt line to setup
1600  *      @act: irqaction for the interrupt
1601  *
1602  * Used to statically setup per-cpu interrupts in the early boot process.
1603  */
1604 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1605 {
1606         struct irq_desc *desc = irq_to_desc(irq);
1607         int retval;
1608
1609         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1610                 return -EINVAL;
1611         chip_bus_lock(desc);
1612         retval = __setup_irq(irq, desc, act);
1613         chip_bus_sync_unlock(desc);
1614
1615         return retval;
1616 }
1617
1618 /**
1619  *      request_percpu_irq - allocate a percpu interrupt line
1620  *      @irq: Interrupt line to allocate
1621  *      @handler: Function to be called when the IRQ occurs.
1622  *      @devname: An ascii name for the claiming device
1623  *      @dev_id: A percpu cookie passed back to the handler function
1624  *
1625  *      This call allocates interrupt resources, but doesn't
1626  *      automatically enable the interrupt. It has to be done on each
1627  *      CPU using enable_percpu_irq().
1628  *
1629  *      Dev_id must be globally unique. It is a per-cpu variable, and
1630  *      the handler gets called with the interrupted CPU's instance of
1631  *      that variable.
1632  */
1633 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1634                        const char *devname, void __percpu *dev_id)
1635 {
1636         struct irqaction *action;
1637         struct irq_desc *desc;
1638         int retval;
1639
1640         if (!dev_id)
1641                 return -EINVAL;
1642
1643         desc = irq_to_desc(irq);
1644         if (!desc || !irq_settings_can_request(desc) ||
1645             !irq_settings_is_per_cpu_devid(desc))
1646                 return -EINVAL;
1647
1648         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1649         if (!action)
1650                 return -ENOMEM;
1651
1652         action->handler = handler;
1653         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1654         action->name = devname;
1655         action->percpu_dev_id = dev_id;
1656
1657         chip_bus_lock(desc);
1658         retval = __setup_irq(irq, desc, action);
1659         chip_bus_sync_unlock(desc);
1660
1661         if (retval)
1662                 kfree(action);
1663
1664         return retval;
1665 }