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 #define pr_fmt(fmt) "genirq: " fmt
  11
  12 #include <linux/irq.h>
  13 #include <linux/kthread.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/slab.h>
  18 #include <linux/sched.h>
  19
  20 #include "internals.h"
  21
  22 #ifdef CONFIG_IRQ_FORCED_THREADING
  23 __read_mostly bool force_irqthreads;
  24
  25 static int __init setup_forced_irqthreads(char *arg)
  26 {
  27         force_irqthreads = true;
  28         return 0;
  29 }
  30 early_param("threadirqs", setup_forced_irqthreads);
  31 #endif
  32
  33 /**
  34  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  35  *      @irq: interrupt number to wait for
  36  *
  37  *      This function waits for any pending IRQ handlers for this interrupt
  38  *      to complete before returning. If you use this function while
  39  *      holding a resource the IRQ handler may need you will deadlock.
  40  *
  41  *      This function may be called - with care - from IRQ context.
  42  */
  43 void synchronize_irq(unsigned int irq)
  44 {
  45         struct irq_desc *desc = irq_to_desc(irq);
  46         bool inprogress;
  47
  48         if (!desc)
  49                 return;
  50
  51         do {
  52                 unsigned long flags;
  53
  54                 /*
  55                  * Wait until we're out of the critical section.  This might
  56                  * give the wrong answer due to the lack of memory barriers.
  57                  */
  58                 while (irqd_irq_inprogress(&desc->irq_data))
  59                         cpu_relax();
  60
  61                 /* Ok, that indicated we're done: double-check carefully. */
  62                 raw_spin_lock_irqsave(&desc->lock, flags);
  63                 inprogress = irqd_irq_inprogress(&desc->irq_data);
  64                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  65
  66                 /* Oops, that failed? */
  67         } while (inprogress);
  68
  69         /*
  70          * We made sure that no hardirq handler is running. Now verify
  71          * that no threaded handlers are active.
  72          */
  73         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
  74 }
  75 EXPORT_SYMBOL(synchronize_irq);
  76
  77 #ifdef CONFIG_SMP
  78 cpumask_var_t irq_default_affinity;
  79
  80 /**
  81  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
  82  *      @irq:           Interrupt to check
  83  *
  84  */
  85 int irq_can_set_affinity(unsigned int irq)
  86 {
  87         struct irq_desc *desc = irq_to_desc(irq);
  88
  89         if (!desc || !irqd_can_balance(&desc->irq_data) ||
  90             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
  91                 return 0;
  92
  93         return 1;
  94 }
  95
  96 /**
  97  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
  98  *      @desc:          irq descriptor which has affitnity changed
  99  *
 100  *      We just set IRQTF_AFFINITY and delegate the affinity setting
 101  *      to the interrupt thread itself. We can not call
 102  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 103  *      code can be called from hard interrupt context.
 104  */
 105 void irq_set_thread_affinity(struct irq_desc *desc)
 106 {
 107         struct irqaction *action = desc->action;
 108
 109         while (action) {
 110                 if (action->thread)
 111                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
 112                 action = action->next;
 113         }
 114 }
 115
 116 #ifdef CONFIG_GENERIC_PENDING_IRQ
 117 static inline bool irq_can_move_pcntxt(struct irq_data *data)
 118 {
 119         return irqd_can_move_in_process_context(data);
 120 }
 121 static inline bool irq_move_pending(struct irq_data *data)
 122 {
 123         return irqd_is_setaffinity_pending(data);
 124 }
 125 static inline void
 126 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 127 {
 128         cpumask_copy(desc->pending_mask, mask);
 129 }
 130 static inline void
 131 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 132 {
 133         cpumask_copy(mask, desc->pending_mask);
 134 }
 135 #else
 136 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 137 static inline bool irq_move_pending(struct irq_data *data) { return false; }
 138 static inline void
 139 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 140 static inline void
 141 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 142 #endif
 143
 144 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
 145 {
 146         struct irq_chip *chip = irq_data_get_irq_chip(data);
 147         struct irq_desc *desc = irq_data_to_desc(data);
 148         int ret = 0;
 149
 150         if (!chip || !chip->irq_set_affinity)
 151                 return -EINVAL;
 152
 153         if (irq_can_move_pcntxt(data)) {
 154                 ret = chip->irq_set_affinity(data, mask, false);
 155                 switch (ret) {
 156                 case IRQ_SET_MASK_OK:
 157                         cpumask_copy(data->affinity, mask);
 158                 case IRQ_SET_MASK_OK_NOCOPY:
 159                         irq_set_thread_affinity(desc);
 160                         ret = 0;
 161                 }
 162         } else {
 163                 irqd_set_move_pending(data);
 164                 irq_copy_pending(desc, mask);
 165         }
 166
 167         if (desc->affinity_notify) {
 168                 kref_get(&desc->affinity_notify->kref);
 169                 schedule_work(&desc->affinity_notify->work);
 170         }
 171         irqd_set(data, IRQD_AFFINITY_SET);
 172
 173         return ret;
 174 }
 175
 176 /**
 177  *      irq_set_affinity - Set the irq affinity of a given irq
 178  *      @irq:           Interrupt to set affinity
 179  *      @mask:          cpumask
 180  *
 181  */
 182 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
 183 {
 184         struct irq_desc *desc = irq_to_desc(irq);
 185         unsigned long flags;
 186         int ret;
 187
 188         if (!desc)
 189                 return -EINVAL;
 190
 191         raw_spin_lock_irqsave(&desc->lock, flags);
 192         ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
 193         raw_spin_unlock_irqrestore(&desc->lock, flags);
 194         return ret;
 195 }
 196
 197 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 198 {
 199         unsigned long flags;
 200         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 201
 202         if (!desc)
 203                 return -EINVAL;
 204         desc->affinity_hint = m;
 205         irq_put_desc_unlock(desc, flags);
 206         return 0;
 207 }
 208 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 209
 210 static void irq_affinity_notify(struct work_struct *work)
 211 {
 212         struct irq_affinity_notify *notify =
 213                 container_of(work, struct irq_affinity_notify, work);
 214         struct irq_desc *desc = irq_to_desc(notify->irq);
 215         cpumask_var_t cpumask;
 216         unsigned long flags;
 217
 218         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 219                 goto out;
 220
 221         raw_spin_lock_irqsave(&desc->lock, flags);
 222         if (irq_move_pending(&desc->irq_data))
 223                 irq_get_pending(cpumask, desc);
 224         else
 225                 cpumask_copy(cpumask, desc->irq_data.affinity);
 226         raw_spin_unlock_irqrestore(&desc->lock, flags);
 227
 228         notify->notify(notify, cpumask);
 229
 230         free_cpumask_var(cpumask);
 231 out:
 232         kref_put(&notify->kref, notify->release);
 233 }
 234
 235 /**
 236  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 237  *      @irq:           Interrupt for which to enable/disable notification
 238  *      @notify:        Context for notification, or %NULL to disable
 239  *                      notification.  Function pointers must be initialised;
 240  *                      the other fields will be initialised by this function.
 241  *
 242  *      Must be called in process context.  Notification may only be enabled
 243  *      after the IRQ is allocated and must be disabled before the IRQ is
 244  *      freed using free_irq().
 245  */
 246 int
 247 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 248 {
 249         struct irq_desc *desc = irq_to_desc(irq);
 250         struct irq_affinity_notify *old_notify;
 251         unsigned long flags;
 252
 253         /* The release function is promised process context */
 254         might_sleep();
 255
 256         if (!desc)
 257                 return -EINVAL;
 258
 259         /* Complete initialisation of *notify */
 260         if (notify) {
 261                 notify->irq = irq;
 262                 kref_init(&notify->kref);
 263                 INIT_WORK(&notify->work, irq_affinity_notify);
 264         }
 265
 266         raw_spin_lock_irqsave(&desc->lock, flags);
 267         old_notify = desc->affinity_notify;
 268         desc->affinity_notify = notify;
 269         raw_spin_unlock_irqrestore(&desc->lock, flags);
 270
 271         if (old_notify)
 272                 kref_put(&old_notify->kref, old_notify->release);
 273
 274         return 0;
 275 }
 276 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 277
 278 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 279 /*
 280  * Generic version of the affinity autoselector.
 281  */
 282 static int
 283 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 284 {
 285         struct irq_chip *chip = irq_desc_get_chip(desc);
 286         struct cpumask *set = irq_default_affinity;
 287         int ret, node = desc->irq_data.node;
 288
 289         /* Excludes PER_CPU and NO_BALANCE interrupts */
 290         if (!irq_can_set_affinity(irq))
 291                 return 0;
 292
 293         /*
 294          * Preserve an userspace affinity setup, but make sure that
 295          * one of the targets is online.
 296          */
 297         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 298                 if (cpumask_intersects(desc->irq_data.affinity,
 299                                        cpu_online_mask))
 300                         set = desc->irq_data.affinity;
 301                 else
 302                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 303         }
 304
 305         cpumask_and(mask, cpu_online_mask, set);
 306         if (node != NUMA_NO_NODE) {
 307                 const struct cpumask *nodemask = cpumask_of_node(node);
 308
 309                 /* make sure at least one of the cpus in nodemask is online */
 310                 if (cpumask_intersects(mask, nodemask))
 311                         cpumask_and(mask, mask, nodemask);
 312         }
 313         ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
 314         switch (ret) {
 315         case IRQ_SET_MASK_OK:
 316                 cpumask_copy(desc->irq_data.affinity, mask);
 317         case IRQ_SET_MASK_OK_NOCOPY:
 318                 irq_set_thread_affinity(desc);
 319         }
 320         return 0;
 321 }
 322 #else
 323 static inline int
 324 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 325 {
 326         return irq_select_affinity(irq);
 327 }
 328 #endif
 329
 330 /*
 331  * Called when affinity is set via /proc/irq
 332  */
 333 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 334 {
 335         struct irq_desc *desc = irq_to_desc(irq);
 336         unsigned long flags;
 337         int ret;
 338
 339         raw_spin_lock_irqsave(&desc->lock, flags);
 340         ret = setup_affinity(irq, desc, mask);
 341         raw_spin_unlock_irqrestore(&desc->lock, flags);
 342         return ret;
 343 }
 344
 345 #else
 346 static inline int
 347 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 348 {
 349         return 0;
 350 }
 351 #endif
 352
 353 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 354 {
 355         if (suspend) {
 356                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 357                         return;
 358                 desc->istate |= IRQS_SUSPENDED;
 359         }
 360
 361         if (!desc->depth++)
 362                 irq_disable(desc);
 363 }
 364
 365 static int __disable_irq_nosync(unsigned int irq)
 366 {
 367         unsigned long flags;
 368         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 369
 370         if (!desc)
 371                 return -EINVAL;
 372         __disable_irq(desc, irq, false);
 373         irq_put_desc_busunlock(desc, flags);
 374         return 0;
 375 }
 376
 377 /**
 378  *      disable_irq_nosync - disable an irq without waiting
 379  *      @irq: Interrupt to disable
 380  *
 381  *      Disable the selected interrupt line.  Disables and Enables are
 382  *      nested.
 383  *      Unlike disable_irq(), this function does not ensure existing
 384  *      instances of the IRQ handler have completed before returning.
 385  *
 386  *      This function may be called from IRQ context.
 387  */
 388 void disable_irq_nosync(unsigned int irq)
 389 {
 390         __disable_irq_nosync(irq);
 391 }
 392 EXPORT_SYMBOL(disable_irq_nosync);
 393
 394 /**
 395  *      disable_irq - disable an irq and wait for completion
 396  *      @irq: Interrupt to disable
 397  *
 398  *      Disable the selected interrupt line.  Enables and Disables are
 399  *      nested.
 400  *      This function waits for any pending IRQ handlers for this interrupt
 401  *      to complete before returning. If you use this function while
 402  *      holding a resource the IRQ handler may need you will deadlock.
 403  *
 404  *      This function may be called - with care - from IRQ context.
 405  */
 406 void disable_irq(unsigned int irq)
 407 {
 408         if (!__disable_irq_nosync(irq))
 409                 synchronize_irq(irq);
 410 }
 411 EXPORT_SYMBOL(disable_irq);
 412
 413 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
 414 {
 415         if (resume) {
 416                 if (!(desc->istate & IRQS_SUSPENDED)) {
 417                         if (!desc->action)
 418                                 return;
 419                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
 420                                 return;
 421                         /* Pretend that it got disabled ! */
 422                         desc->depth++;
 423                 }
 424                 desc->istate &= ~IRQS_SUSPENDED;
 425         }
 426
 427         switch (desc->depth) {
 428         case 0:
 429  err_out:
 430                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 431                 break;
 432         case 1: {
 433                 if (desc->istate & IRQS_SUSPENDED)
 434                         goto err_out;
 435                 /* Prevent probing on this irq: */
 436                 irq_settings_set_noprobe(desc);
 437                 irq_enable(desc);
 438                 check_irq_resend(desc, irq);
 439                 /* fall-through */
 440         }
 441         default:
 442                 desc->depth--;
 443         }
 444 }
 445
 446 /**
 447  *      enable_irq - enable handling of an irq
 448  *      @irq: Interrupt to enable
 449  *
 450  *      Undoes the effect of one call to disable_irq().  If this
 451  *      matches the last disable, processing of interrupts on this
 452  *      IRQ line is re-enabled.
 453  *
 454  *      This function may be called from IRQ context only when
 455  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 456  */
 457 void enable_irq(unsigned int irq)
 458 {
 459         unsigned long flags;
 460         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 461
 462         if (!desc)
 463                 return;
 464         if (WARN(!desc->irq_data.chip,
 465                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 466                 goto out;
 467
 468         __enable_irq(desc, irq, false);
 469 out:
 470         irq_put_desc_busunlock(desc, flags);
 471 }
 472 EXPORT_SYMBOL(enable_irq);
 473
 474 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 475 {
 476         struct irq_desc *desc = irq_to_desc(irq);
 477         int ret = -ENXIO;
 478
 479         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 480                 return 0;
 481
 482         if (desc->irq_data.chip->irq_set_wake)
 483                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 484
 485         return ret;
 486 }
 487
 488 /**
 489  *      irq_set_irq_wake - control irq power management wakeup
 490  *      @irq:   interrupt to control
 491  *      @on:    enable/disable power management wakeup
 492  *
 493  *      Enable/disable power management wakeup mode, which is
 494  *      disabled by default.  Enables and disables must match,
 495  *      just as they match for non-wakeup mode support.
 496  *
 497  *      Wakeup mode lets this IRQ wake the system from sleep
 498  *      states like "suspend to RAM".
 499  */
 500 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 501 {
 502         unsigned long flags;
 503         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 504         int ret = 0;
 505
 506         if (!desc)
 507                 return -EINVAL;
 508
 509         /* wakeup-capable irqs can be shared between drivers that
 510          * don't need to have the same sleep mode behaviors.
 511          */
 512         if (on) {
 513                 if (desc->wake_depth++ == 0) {
 514                         ret = set_irq_wake_real(irq, on);
 515                         if (ret)
 516                                 desc->wake_depth = 0;
 517                         else
 518                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 519                 }
 520         } else {
 521                 if (desc->wake_depth == 0) {
 522                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 523                 } else if (--desc->wake_depth == 0) {
 524                         ret = set_irq_wake_real(irq, on);
 525                         if (ret)
 526                                 desc->wake_depth = 1;
 527                         else
 528                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 529                 }
 530         }
 531         irq_put_desc_busunlock(desc, flags);
 532         return ret;
 533 }
 534 EXPORT_SYMBOL(irq_set_irq_wake);
 535
 536 /*
 537  * Internal function that tells the architecture code whether a
 538  * particular irq has been exclusively allocated or is available
 539  * for driver use.
 540  */
 541 int can_request_irq(unsigned int irq, unsigned long irqflags)
 542 {
 543         unsigned long flags;
 544         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 545         int canrequest = 0;
 546
 547         if (!desc)
 548                 return 0;
 549
 550         if (irq_settings_can_request(desc)) {
 551                 if (desc->action)
 552                         if (irqflags & desc->action->flags & IRQF_SHARED)
 553                                 canrequest =1;
 554         }
 555         irq_put_desc_unlock(desc, flags);
 556         return canrequest;
 557 }
 558
 559 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 560                       unsigned long flags)
 561 {
 562         struct irq_chip *chip = desc->irq_data.chip;
 563         int ret, unmask = 0;
 564
 565         if (!chip || !chip->irq_set_type) {
 566                 /*
 567                  * IRQF_TRIGGER_* but the PIC does not support multiple
 568                  * flow-types?
 569                  */
 570                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 571                          chip ? (chip->name ? : "unknown") : "unknown");
 572                 return 0;
 573         }
 574
 575         flags &= IRQ_TYPE_SENSE_MASK;
 576
 577         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 578                 if (!irqd_irq_masked(&desc->irq_data))
 579                         mask_irq(desc);
 580                 if (!irqd_irq_disabled(&desc->irq_data))
 581                         unmask = 1;
 582         }
 583
 584         /* caller masked out all except trigger mode flags */
 585         ret = chip->irq_set_type(&desc->irq_data, flags);
 586
 587         switch (ret) {
 588         case IRQ_SET_MASK_OK:
 589                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 590                 irqd_set(&desc->irq_data, flags);
 591
 592         case IRQ_SET_MASK_OK_NOCOPY:
 593                 flags = irqd_get_trigger_type(&desc->irq_data);
 594                 irq_settings_set_trigger_mask(desc, flags);
 595                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 596                 irq_settings_clr_level(desc);
 597                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 598                         irq_settings_set_level(desc);
 599                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 600                 }
 601
 602                 ret = 0;
 603                 break;
 604         default:
 605                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 606                        flags, irq, chip->irq_set_type);
 607         }
 608         if (unmask)
 609                 unmask_irq(desc);
 610         return ret;
 611 }
 612
 613 /*
 614  * Default primary interrupt handler for threaded interrupts. Is
 615  * assigned as primary handler when request_threaded_irq is called
 616  * with handler == NULL. Useful for oneshot interrupts.
 617  */
 618 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 619 {
 620         return IRQ_WAKE_THREAD;
 621 }
 622
 623 /*
 624  * Primary handler for nested threaded interrupts. Should never be
 625  * called.
 626  */
 627 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 628 {
 629         WARN(1, "Primary handler called for nested irq %d\n", irq);
 630         return IRQ_NONE;
 631 }
 632
 633 static int irq_wait_for_interrupt(struct irqaction *action)
 634 {
 635         set_current_state(TASK_INTERRUPTIBLE);
 636
 637         while (!kthread_should_stop()) {
 638
 639                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 640                                        &action->thread_flags)) {
 641                         __set_current_state(TASK_RUNNING);
 642                         return 0;
 643                 }
 644                 schedule();
 645                 set_current_state(TASK_INTERRUPTIBLE);
 646         }
 647         __set_current_state(TASK_RUNNING);
 648         return -1;
 649 }
 650
 651 /*
 652  * Oneshot interrupts keep the irq line masked until the threaded
 653  * handler finished. unmask if the interrupt has not been disabled and
 654  * is marked MASKED.
 655  */
 656 static void irq_finalize_oneshot(struct irq_desc *desc,
 657                                  struct irqaction *action)
 658 {
 659         if (!(desc->istate & IRQS_ONESHOT))
 660                 return;
 661 again:
 662         chip_bus_lock(desc);
 663         raw_spin_lock_irq(&desc->lock);
 664
 665         /*
 666          * Implausible though it may be we need to protect us against
 667          * the following scenario:
 668          *
 669          * The thread is faster done than the hard interrupt handler
 670          * on the other CPU. If we unmask the irq line then the
 671          * interrupt can come in again and masks the line, leaves due
 672          * to IRQS_INPROGRESS and the irq line is masked forever.
 673          *
 674          * This also serializes the state of shared oneshot handlers
 675          * versus "desc->threads_onehsot |= action->thread_mask;" in
 676          * irq_wake_thread(). See the comment there which explains the
 677          * serialization.
 678          */
 679         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 680                 raw_spin_unlock_irq(&desc->lock);
 681                 chip_bus_sync_unlock(desc);
 682                 cpu_relax();
 683                 goto again;
 684         }
 685
 686         /*
 687          * Now check again, whether the thread should run. Otherwise
 688          * we would clear the threads_oneshot bit of this thread which
 689          * was just set.
 690          */
 691         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 692                 goto out_unlock;
 693
 694         desc->threads_oneshot &= ~action->thread_mask;
 695
 696         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 697             irqd_irq_masked(&desc->irq_data))
 698                 unmask_irq(desc);
 699
 700 out_unlock:
 701         raw_spin_unlock_irq(&desc->lock);
 702         chip_bus_sync_unlock(desc);
 703 }
 704
 705 #ifdef CONFIG_SMP
 706 /*
 707  * Check whether we need to chasnge the affinity of the interrupt thread.
 708  */
 709 static void
 710 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 711 {
 712         cpumask_var_t mask;
 713
 714         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 715                 return;
 716
 717         /*
 718          * In case we are out of memory we set IRQTF_AFFINITY again and
 719          * try again next time
 720          */
 721         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 722                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 723                 return;
 724         }
 725
 726         raw_spin_lock_irq(&desc->lock);
 727         cpumask_copy(mask, desc->irq_data.affinity);
 728         raw_spin_unlock_irq(&desc->lock);
 729
 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);
 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);
 768         return ret;
 769 }
 770
 771 static void wake_threads_waitq(struct irq_desc *desc)
 772 {
 773         if (atomic_dec_and_test(&desc->threads_active) &&
 774             waitqueue_active(&desc->wait_for_threads))
 775                 wake_up(&desc->wait_for_threads);
 776 }
 777
 778 /*
 779  * Interrupt handler thread
 780  */
 781 static int irq_thread(void *data)
 782 {
 783         static const struct sched_param param = {
 784                 .sched_priority = MAX_USER_RT_PRIO/2,
 785         };
 786         struct irqaction *action = data;
 787         struct irq_desc *desc = irq_to_desc(action->irq);
 788         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 789                         struct irqaction *action);
 790
 791         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 792                                         &action->thread_flags))
 793                 handler_fn = irq_forced_thread_fn;
 794         else
 795                 handler_fn = irq_thread_fn;
 796
 797         sched_setscheduler(current, SCHED_FIFO, &param);
 798         current->irq_thread = 1;
 799
 800         while (!irq_wait_for_interrupt(action)) {
 801                 irqreturn_t action_ret;
 802
 803                 irq_thread_check_affinity(desc, action);
 804
 805                 action_ret = handler_fn(desc, action);
 806                 if (!noirqdebug)
 807                         note_interrupt(action->irq, desc, action_ret);
 808
 809                 wake_threads_waitq(desc);
 810         }
 811
 812         /*
 813          * This is the regular exit path. __free_irq() is stopping the
 814          * thread via kthread_stop() after calling
 815          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 816          * oneshot mask bit can be set. We cannot verify that as we
 817          * cannot touch the oneshot mask at this point anymore as
 818          * __setup_irq() might have given out currents thread_mask
 819          * again.
 820          *
 821          * Clear irq_thread. Otherwise exit_irq_thread() would make
 822          * fuzz about an active irq thread going into nirvana.
 823          */
 824         current->irq_thread = 0;
 825         return 0;
 826 }
 827
 828 /*
 829  * Called from do_exit()
 830  */
 831 void exit_irq_thread(void)
 832 {
 833         struct task_struct *tsk = current;
 834         struct irq_desc *desc;
 835         struct irqaction *action;
 836
 837         if (!tsk->irq_thread)
 838                 return;
 839
 840         action = kthread_data(tsk);
 841
 842         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 843                tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
 844
 845         desc = irq_to_desc(action->irq);
 846
 847         /*
 848          * If IRQTF_RUNTHREAD is set, we need to decrement
 849          * desc->threads_active and wake possible waiters.
 850          */
 851         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 852                 wake_threads_waitq(desc);
 853
 854         /* Prevent a stale desc->threads_oneshot */
 855         irq_finalize_oneshot(desc, action);
 856 }
 857
 858 static void irq_setup_forced_threading(struct irqaction *new)
 859 {
 860         if (!force_irqthreads)
 861                 return;
 862         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 863                 return;
 864
 865         new->flags |= IRQF_ONESHOT;
 866
 867         if (!new->thread_fn) {
 868                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 869                 new->thread_fn = new->handler;
 870                 new->handler = irq_default_primary_handler;
 871         }
 872 }
 873
 874 /*
 875  * Internal function to register an irqaction - typically used to
 876  * allocate special interrupts that are part of the architecture.
 877  */
 878 static int
 879 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 880 {
 881         struct irqaction *old, **old_ptr;
 882         unsigned long flags, thread_mask = 0;
 883         int ret, nested, shared = 0;
 884         cpumask_var_t mask;
 885
 886         if (!desc)
 887                 return -EINVAL;
 888
 889         if (desc->irq_data.chip == &no_irq_chip)
 890                 return -ENOSYS;
 891         if (!try_module_get(desc->owner))
 892                 return -ENODEV;
 893         /*
 894          * Some drivers like serial.c use request_irq() heavily,
 895          * so we have to be careful not to interfere with a
 896          * running system.
 897          */
 898         if (new->flags & IRQF_SAMPLE_RANDOM) {
 899                 /*
 900                  * This function might sleep, we want to call it first,
 901                  * outside of the atomic block.
 902                  * Yes, this might clear the entropy pool if the wrong
 903                  * driver is attempted to be loaded, without actually
 904                  * installing a new handler, but is this really a problem,
 905                  * only the sysadmin is able to do this.
 906                  */
 907                 rand_initialize_irq(irq);
 908         }
 909
 910         /*
 911          * Check whether the interrupt nests into another interrupt
 912          * thread.
 913          */
 914         nested = irq_settings_is_nested_thread(desc);
 915         if (nested) {
 916                 if (!new->thread_fn) {
 917                         ret = -EINVAL;
 918                         goto out_mput;
 919                 }
 920                 /*
 921                  * Replace the primary handler which was provided from
 922                  * the driver for non nested interrupt handling by the
 923                  * dummy function which warns when called.
 924                  */
 925                 new->handler = irq_nested_primary_handler;
 926         } else {
 927                 if (irq_settings_can_thread(desc))
 928                         irq_setup_forced_threading(new);
 929         }
 930
 931         /*
 932          * Create a handler thread when a thread function is supplied
 933          * and the interrupt does not nest into another interrupt
 934          * thread.
 935          */
 936         if (new->thread_fn && !nested) {
 937                 struct task_struct *t;
 938
 939                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 940                                    new->name);
 941                 if (IS_ERR(t)) {
 942                         ret = PTR_ERR(t);
 943                         goto out_mput;
 944                 }
 945                 /*
 946                  * We keep the reference to the task struct even if
 947                  * the thread dies to avoid that the interrupt code
 948                  * references an already freed task_struct.
 949                  */
 950                 get_task_struct(t);
 951                 new->thread = t;
 952         }
 953
 954         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 955                 ret = -ENOMEM;
 956                 goto out_thread;
 957         }
 958
 959         /*
 960          * The following block of code has to be executed atomically
 961          */
 962         raw_spin_lock_irqsave(&desc->lock, flags);
 963         old_ptr = &desc->action;
 964         old = *old_ptr;
 965         if (old) {
 966                 /*
 967                  * Can't share interrupts unless both agree to and are
 968                  * the same type (level, edge, polarity). So both flag
 969                  * fields must have IRQF_SHARED set and the bits which
 970                  * set the trigger type must match. Also all must
 971                  * agree on ONESHOT.
 972                  */
 973                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
 974                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
 975                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
 976                         goto mismatch;
 977
 978                 /* All handlers must agree on per-cpuness */
 979                 if ((old->flags & IRQF_PERCPU) !=
 980                     (new->flags & IRQF_PERCPU))
 981                         goto mismatch;
 982
 983                 /* add new interrupt at end of irq queue */
 984                 do {
 985                         /*
 986                          * Or all existing action->thread_mask bits,
 987                          * so we can find the next zero bit for this
 988                          * new action.
 989                          */
 990                         thread_mask |= old->thread_mask;
 991                         old_ptr = &old->next;
 992                         old = *old_ptr;
 993                 } while (old);
 994                 shared = 1;
 995         }
 996
 997         /*
 998          * Setup the thread mask for this irqaction for ONESHOT. For
 999          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1000          * conditional in irq_wake_thread().
1001          */
1002         if (new->flags & IRQF_ONESHOT) {
1003                 /*
1004                  * Unlikely to have 32 resp 64 irqs sharing one line,
1005                  * but who knows.
1006                  */
1007                 if (thread_mask == ~0UL) {
1008                         ret = -EBUSY;
1009                         goto out_mask;
1010                 }
1011                 /*
1012                  * The thread_mask for the action is or'ed to
1013                  * desc->thread_active to indicate that the
1014                  * IRQF_ONESHOT thread handler has been woken, but not
1015                  * yet finished. The bit is cleared when a thread
1016                  * completes. When all threads of a shared interrupt
1017                  * line have completed desc->threads_active becomes
1018                  * zero and the interrupt line is unmasked. See
1019                  * handle.c:irq_wake_thread() for further information.
1020                  *
1021                  * If no thread is woken by primary (hard irq context)
1022                  * interrupt handlers, then desc->threads_active is
1023                  * also checked for zero to unmask the irq line in the
1024                  * affected hard irq flow handlers
1025                  * (handle_[fasteoi|level]_irq).
1026                  *
1027                  * The new action gets the first zero bit of
1028                  * thread_mask assigned. See the loop above which or's
1029                  * all existing action->thread_mask bits.
1030                  */
1031                 new->thread_mask = 1 << ffz(thread_mask);
1032
1033         } else if (new->handler == irq_default_primary_handler) {
1034                 /*
1035                  * The interrupt was requested with handler = NULL, so
1036                  * we use the default primary handler for it. But it
1037                  * does not have the oneshot flag set. In combination
1038                  * with level interrupts this is deadly, because the
1039                  * default primary handler just wakes the thread, then
1040                  * the irq lines is reenabled, but the device still
1041                  * has the level irq asserted. Rinse and repeat....
1042                  *
1043                  * While this works for edge type interrupts, we play
1044                  * it safe and reject unconditionally because we can't
1045                  * say for sure which type this interrupt really
1046                  * has. The type flags are unreliable as the
1047                  * underlying chip implementation can override them.
1048                  */
1049                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1050                        irq);
1051                 ret = -EINVAL;
1052                 goto out_mask;
1053         }
1054
1055         if (!shared) {
1056                 init_waitqueue_head(&desc->wait_for_threads);
1057
1058                 /* Setup the type (level, edge polarity) if configured: */
1059                 if (new->flags & IRQF_TRIGGER_MASK) {
1060                         ret = __irq_set_trigger(desc, irq,
1061                                         new->flags & IRQF_TRIGGER_MASK);
1062
1063                         if (ret)
1064                                 goto out_mask;
1065                 }
1066
1067                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1068                                   IRQS_ONESHOT | IRQS_WAITING);
1069                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1070
1071                 if (new->flags & IRQF_PERCPU) {
1072                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1073                         irq_settings_set_per_cpu(desc);
1074                 }
1075
1076                 if (new->flags & IRQF_ONESHOT)
1077                         desc->istate |= IRQS_ONESHOT;
1078
1079                 if (irq_settings_can_autoenable(desc))
1080                         irq_startup(desc, true);
1081                 else
1082                         /* Undo nested disables: */
1083                         desc->depth = 1;
1084
1085                 /* Exclude IRQ from balancing if requested */
1086                 if (new->flags & IRQF_NOBALANCING) {
1087                         irq_settings_set_no_balancing(desc);
1088                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1089                 }
1090
1091                 /* Set default affinity mask once everything is setup */
1092                 setup_affinity(irq, desc, mask);
1093
1094         } else if (new->flags & IRQF_TRIGGER_MASK) {
1095                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1096                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1097
1098                 if (nmsk != omsk)
1099                         /* hope the handler works with current  trigger mode */
1100                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1101                                    irq, nmsk, omsk);
1102         }
1103
1104         new->irq = irq;
1105         *old_ptr = new;
1106
1107         /* Reset broken irq detection when installing new handler */
1108         desc->irq_count = 0;
1109         desc->irqs_unhandled = 0;
1110
1111         /*
1112          * Check whether we disabled the irq via the spurious handler
1113          * before. Reenable it and give it another chance.
1114          */
1115         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1116                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1117                 __enable_irq(desc, irq, false);
1118         }
1119
1120         raw_spin_unlock_irqrestore(&desc->lock, flags);
1121
1122         /*
1123          * Strictly no need to wake it up, but hung_task complains
1124          * when no hard interrupt wakes the thread up.
1125          */
1126         if (new->thread)
1127                 wake_up_process(new->thread);
1128
1129         register_irq_proc(irq, desc);
1130         new->dir = NULL;
1131         register_handler_proc(irq, new);
1132         free_cpumask_var(mask);
1133
1134         return 0;
1135
1136 mismatch:
1137         if (!(new->flags & IRQF_PROBE_SHARED)) {
1138                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1139                        irq, new->flags, new->name, old->flags, old->name);
1140 #ifdef CONFIG_DEBUG_SHIRQ
1141                 dump_stack();
1142 #endif
1143         }
1144         ret = -EBUSY;
1145
1146 out_mask:
1147         raw_spin_unlock_irqrestore(&desc->lock, flags);
1148         free_cpumask_var(mask);
1149
1150 out_thread:
1151         if (new->thread) {
1152                 struct task_struct *t = new->thread;
1153
1154                 new->thread = NULL;
1155                 kthread_stop(t);
1156                 put_task_struct(t);
1157         }
1158 out_mput:
1159         module_put(desc->owner);
1160         return ret;
1161 }
1162
1163 /**
1164  *      setup_irq - setup an interrupt
1165  *      @irq: Interrupt line to setup
1166  *      @act: irqaction for the interrupt
1167  *
1168  * Used to statically setup interrupts in the early boot process.
1169  */
1170 int setup_irq(unsigned int irq, struct irqaction *act)
1171 {
1172         int retval;
1173         struct irq_desc *desc = irq_to_desc(irq);
1174
1175         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1176                 return -EINVAL;
1177         chip_bus_lock(desc);
1178         retval = __setup_irq(irq, desc, act);
1179         chip_bus_sync_unlock(desc);
1180
1181         return retval;
1182 }
1183 EXPORT_SYMBOL_GPL(setup_irq);
1184
1185 /*
1186  * Internal function to unregister an irqaction - used to free
1187  * regular and special interrupts that are part of the architecture.
1188  */
1189 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1190 {
1191         struct irq_desc *desc = irq_to_desc(irq);
1192         struct irqaction *action, **action_ptr;
1193         unsigned long flags;
1194
1195         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1196
1197         if (!desc)
1198                 return NULL;
1199
1200         raw_spin_lock_irqsave(&desc->lock, flags);
1201
1202         /*
1203          * There can be multiple actions per IRQ descriptor, find the right
1204          * one based on the dev_id:
1205          */
1206         action_ptr = &desc->action;
1207         for (;;) {
1208                 action = *action_ptr;
1209
1210                 if (!action) {
1211                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1212                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1213
1214                         return NULL;
1215                 }
1216
1217                 if (action->dev_id == dev_id)
1218                         break;
1219                 action_ptr = &action->next;
1220         }
1221
1222         /* Found it - now remove it from the list of entries: */
1223         *action_ptr = action->next;
1224
1225         /* If this was the last handler, shut down the IRQ line: */
1226         if (!desc->action)
1227                 irq_shutdown(desc);
1228
1229 #ifdef CONFIG_SMP
1230         /* make sure affinity_hint is cleaned up */
1231         if (WARN_ON_ONCE(desc->affinity_hint))
1232                 desc->affinity_hint = NULL;
1233 #endif
1234
1235         raw_spin_unlock_irqrestore(&desc->lock, flags);
1236
1237         unregister_handler_proc(irq, action);
1238
1239         /* Make sure it's not being used on another CPU: */
1240         synchronize_irq(irq);
1241
1242 #ifdef CONFIG_DEBUG_SHIRQ
1243         /*
1244          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1245          * event to happen even now it's being freed, so let's make sure that
1246          * is so by doing an extra call to the handler ....
1247          *
1248          * ( We do this after actually deregistering it, to make sure that a
1249          *   'real' IRQ doesn't run in * parallel with our fake. )
1250          */
1251         if (action->flags & IRQF_SHARED) {
1252                 local_irq_save(flags);
1253                 action->handler(irq, dev_id);
1254                 local_irq_restore(flags);
1255         }
1256 #endif
1257
1258         if (action->thread) {
1259                 kthread_stop(action->thread);
1260                 put_task_struct(action->thread);
1261         }
1262
1263         module_put(desc->owner);
1264         return action;
1265 }
1266
1267 /**
1268  *      remove_irq - free an interrupt
1269  *      @irq: Interrupt line to free
1270  *      @act: irqaction for the interrupt
1271  *
1272  * Used to remove interrupts statically setup by the early boot process.
1273  */
1274 void remove_irq(unsigned int irq, struct irqaction *act)
1275 {
1276         struct irq_desc *desc = irq_to_desc(irq);
1277
1278         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1279             __free_irq(irq, act->dev_id);
1280 }
1281 EXPORT_SYMBOL_GPL(remove_irq);
1282
1283 /**
1284  *      free_irq - free an interrupt allocated with request_irq
1285  *      @irq: Interrupt line to free
1286  *      @dev_id: Device identity to free
1287  *
1288  *      Remove an interrupt handler. The handler is removed and if the
1289  *      interrupt line is no longer in use by any driver it is disabled.
1290  *      On a shared IRQ the caller must ensure the interrupt is disabled
1291  *      on the card it drives before calling this function. The function
1292  *      does not return until any executing interrupts for this IRQ
1293  *      have completed.
1294  *
1295  *      This function must not be called from interrupt context.
1296  */
1297 void free_irq(unsigned int irq, void *dev_id)
1298 {
1299         struct irq_desc *desc = irq_to_desc(irq);
1300
1301         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1302                 return;
1303
1304 #ifdef CONFIG_SMP
1305         if (WARN_ON(desc->affinity_notify))
1306                 desc->affinity_notify = NULL;
1307 #endif
1308
1309         chip_bus_lock(desc);
1310         kfree(__free_irq(irq, dev_id));
1311         chip_bus_sync_unlock(desc);
1312 }
1313 EXPORT_SYMBOL(free_irq);
1314
1315 /**
1316  *      request_threaded_irq - allocate an interrupt line
1317  *      @irq: Interrupt line to allocate
1318  *      @handler: Function to be called when the IRQ occurs.
1319  *                Primary handler for threaded interrupts
1320  *                If NULL and thread_fn != NULL the default
1321  *                primary handler is installed
1322  *      @thread_fn: Function called from the irq handler thread
1323  *                  If NULL, no irq thread is created
1324  *      @irqflags: Interrupt type flags
1325  *      @devname: An ascii name for the claiming device
1326  *      @dev_id: A cookie passed back to the handler function
1327  *
1328  *      This call allocates interrupt resources and enables the
1329  *      interrupt line and IRQ handling. From the point this
1330  *      call is made your handler function may be invoked. Since
1331  *      your handler function must clear any interrupt the board
1332  *      raises, you must take care both to initialise your hardware
1333  *      and to set up the interrupt handler in the right order.
1334  *
1335  *      If you want to set up a threaded irq handler for your device
1336  *      then you need to supply @handler and @thread_fn. @handler is
1337  *      still called in hard interrupt context and has to check
1338  *      whether the interrupt originates from the device. If yes it
1339  *      needs to disable the interrupt on the device and return
1340  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1341  *      @thread_fn. This split handler design is necessary to support
1342  *      shared interrupts.
1343  *
1344  *      Dev_id must be globally unique. Normally the address of the
1345  *      device data structure is used as the cookie. Since the handler
1346  *      receives this value it makes sense to use it.
1347  *
1348  *      If your interrupt is shared you must pass a non NULL dev_id
1349  *      as this is required when freeing the interrupt.
1350  *
1351  *      Flags:
1352  *
1353  *      IRQF_SHARED             Interrupt is shared
1354  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1355  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1356  *
1357  */
1358 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1359                          irq_handler_t thread_fn, unsigned long irqflags,
1360                          const char *devname, void *dev_id)
1361 {
1362         struct irqaction *action;
1363         struct irq_desc *desc;
1364         int retval;
1365
1366         /*
1367          * Sanity-check: shared interrupts must pass in a real dev-ID,
1368          * otherwise we'll have trouble later trying to figure out
1369          * which interrupt is which (messes up the interrupt freeing
1370          * logic etc).
1371          */
1372         if ((irqflags & IRQF_SHARED) && !dev_id)
1373                 return -EINVAL;
1374
1375         desc = irq_to_desc(irq);
1376         if (!desc)
1377                 return -EINVAL;
1378
1379         if (!irq_settings_can_request(desc) ||
1380             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1381                 return -EINVAL;
1382
1383         if (!handler) {
1384                 if (!thread_fn)
1385                         return -EINVAL;
1386                 handler = irq_default_primary_handler;
1387         }
1388
1389         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1390         if (!action)
1391                 return -ENOMEM;
1392
1393         action->handler = handler;
1394         action->thread_fn = thread_fn;
1395         action->flags = irqflags;
1396         action->name = devname;
1397         action->dev_id = dev_id;
1398
1399         chip_bus_lock(desc);
1400         retval = __setup_irq(irq, desc, action);
1401         chip_bus_sync_unlock(desc);
1402
1403         if (retval)
1404                 kfree(action);
1405
1406 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1407         if (!retval && (irqflags & IRQF_SHARED)) {
1408                 /*
1409                  * It's a shared IRQ -- the driver ought to be prepared for it
1410                  * to happen immediately, so let's make sure....
1411                  * We disable the irq to make sure that a 'real' IRQ doesn't
1412                  * run in parallel with our fake.
1413                  */
1414                 unsigned long flags;
1415
1416                 disable_irq(irq);
1417                 local_irq_save(flags);
1418
1419                 handler(irq, dev_id);
1420
1421                 local_irq_restore(flags);
1422                 enable_irq(irq);
1423         }
1424 #endif
1425         return retval;
1426 }
1427 EXPORT_SYMBOL(request_threaded_irq);
1428
1429 /**
1430  *      request_any_context_irq - allocate an interrupt line
1431  *      @irq: Interrupt line to allocate
1432  *      @handler: Function to be called when the IRQ occurs.
1433  *                Threaded handler for threaded interrupts.
1434  *      @flags: Interrupt type flags
1435  *      @name: An ascii name for the claiming device
1436  *      @dev_id: A cookie passed back to the handler function
1437  *
1438  *      This call allocates interrupt resources and enables the
1439  *      interrupt line and IRQ handling. It selects either a
1440  *      hardirq or threaded handling method depending on the
1441  *      context.
1442  *
1443  *      On failure, it returns a negative value. On success,
1444  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1445  */
1446 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1447                             unsigned long flags, const char *name, void *dev_id)
1448 {
1449         struct irq_desc *desc = irq_to_desc(irq);
1450         int ret;
1451
1452         if (!desc)
1453                 return -EINVAL;
1454
1455         if (irq_settings_is_nested_thread(desc)) {
1456                 ret = request_threaded_irq(irq, NULL, handler,
1457                                            flags, name, dev_id);
1458                 return !ret ? IRQC_IS_NESTED : ret;
1459         }
1460
1461         ret = request_irq(irq, handler, flags, name, dev_id);
1462         return !ret ? IRQC_IS_HARDIRQ : ret;
1463 }
1464 EXPORT_SYMBOL_GPL(request_any_context_irq);
1465
1466 void enable_percpu_irq(unsigned int irq, unsigned int type)
1467 {
1468         unsigned int cpu = smp_processor_id();
1469         unsigned long flags;
1470         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1471
1472         if (!desc)
1473                 return;
1474
1475         type &= IRQ_TYPE_SENSE_MASK;
1476         if (type != IRQ_TYPE_NONE) {
1477                 int ret;
1478
1479                 ret = __irq_set_trigger(desc, irq, type);
1480
1481                 if (ret) {
1482                         WARN(1, "failed to set type for IRQ%d\n", irq);
1483                         goto out;
1484                 }
1485         }
1486
1487         irq_percpu_enable(desc, cpu);
1488 out:
1489         irq_put_desc_unlock(desc, flags);
1490 }
1491
1492 void disable_percpu_irq(unsigned int irq)
1493 {
1494         unsigned int cpu = smp_processor_id();
1495         unsigned long flags;
1496         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1497
1498         if (!desc)
1499                 return;
1500
1501         irq_percpu_disable(desc, cpu);
1502         irq_put_desc_unlock(desc, flags);
1503 }
1504
1505 /*
1506  * Internal function to unregister a percpu irqaction.
1507  */
1508 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1509 {
1510         struct irq_desc *desc = irq_to_desc(irq);
1511         struct irqaction *action;
1512         unsigned long flags;
1513
1514         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1515
1516         if (!desc)
1517                 return NULL;
1518
1519         raw_spin_lock_irqsave(&desc->lock, flags);
1520
1521         action = desc->action;
1522         if (!action || action->percpu_dev_id != dev_id) {
1523                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1524                 goto bad;
1525         }
1526
1527         if (!cpumask_empty(desc->percpu_enabled)) {
1528                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1529                      irq, cpumask_first(desc->percpu_enabled));
1530                 goto bad;
1531         }
1532
1533         /* Found it - now remove it from the list of entries: */
1534         desc->action = NULL;
1535
1536         raw_spin_unlock_irqrestore(&desc->lock, flags);
1537
1538         unregister_handler_proc(irq, action);
1539
1540         module_put(desc->owner);
1541         return action;
1542
1543 bad:
1544         raw_spin_unlock_irqrestore(&desc->lock, flags);
1545         return NULL;
1546 }
1547
1548 /**
1549  *      remove_percpu_irq - free a per-cpu interrupt
1550  *      @irq: Interrupt line to free
1551  *      @act: irqaction for the interrupt
1552  *
1553  * Used to remove interrupts statically setup by the early boot process.
1554  */
1555 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1556 {
1557         struct irq_desc *desc = irq_to_desc(irq);
1558
1559         if (desc && irq_settings_is_per_cpu_devid(desc))
1560             __free_percpu_irq(irq, act->percpu_dev_id);
1561 }
1562
1563 /**
1564  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1565  *      @irq: Interrupt line to free
1566  *      @dev_id: Device identity to free
1567  *
1568  *      Remove a percpu interrupt handler. The handler is removed, but
1569  *      the interrupt line is not disabled. This must be done on each
1570  *      CPU before calling this function. The function does not return
1571  *      until any executing interrupts for this IRQ have completed.
1572  *
1573  *      This function must not be called from interrupt context.
1574  */
1575 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1576 {
1577         struct irq_desc *desc = irq_to_desc(irq);
1578
1579         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1580                 return;
1581
1582         chip_bus_lock(desc);
1583         kfree(__free_percpu_irq(irq, dev_id));
1584         chip_bus_sync_unlock(desc);
1585 }
1586
1587 /**
1588  *      setup_percpu_irq - setup a per-cpu interrupt
1589  *      @irq: Interrupt line to setup
1590  *      @act: irqaction for the interrupt
1591  *
1592  * Used to statically setup per-cpu interrupts in the early boot process.
1593  */
1594 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1595 {
1596         struct irq_desc *desc = irq_to_desc(irq);
1597         int retval;
1598
1599         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1600                 return -EINVAL;
1601         chip_bus_lock(desc);
1602         retval = __setup_irq(irq, desc, act);
1603         chip_bus_sync_unlock(desc);
1604
1605         return retval;
1606 }
1607
1608 /**
1609  *      request_percpu_irq - allocate a percpu interrupt line
1610  *      @irq: Interrupt line to allocate
1611  *      @handler: Function to be called when the IRQ occurs.
1612  *      @devname: An ascii name for the claiming device
1613  *      @dev_id: A percpu cookie passed back to the handler function
1614  *
1615  *      This call allocates interrupt resources, but doesn't
1616  *      automatically enable the interrupt. It has to be done on each
1617  *      CPU using enable_percpu_irq().
1618  *
1619  *      Dev_id must be globally unique. It is a per-cpu variable, and
1620  *      the handler gets called with the interrupted CPU's instance of
1621  *      that variable.
1622  */
1623 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1624                        const char *devname, void __percpu *dev_id)
1625 {
1626         struct irqaction *action;
1627         struct irq_desc *desc;
1628         int retval;
1629
1630         if (!dev_id)
1631                 return -EINVAL;
1632
1633         desc = irq_to_desc(irq);
1634         if (!desc || !irq_settings_can_request(desc) ||
1635             !irq_settings_is_per_cpu_devid(desc))
1636                 return -EINVAL;
1637
1638         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1639         if (!action)
1640                 return -ENOMEM;
1641
1642         action->handler = handler;
1643         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1644         action->name = devname;
1645         action->percpu_dev_id = dev_id;
1646
1647         chip_bus_lock(desc);
1648         retval = __setup_irq(irq, desc, action);
1649         chip_bus_sync_unlock(desc);
1650
1651         if (retval)
1652                 kfree(action);
1653
1654         return retval;
1655 }