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 #include <linux/task_work.h>
  20
  21 #include "internals.h"
  22
  23 #ifdef CONFIG_IRQ_FORCED_THREADING
  24 __read_mostly bool force_irqthreads;
  25
  26 static int __init setup_forced_irqthreads(char *arg)
  27 {
  28         force_irqthreads = true;
  29         return 0;
  30 }
  31 early_param("threadirqs", setup_forced_irqthreads);
  32 #endif
  33
  34 /**
  35  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  36  *      @irq: interrupt number to wait for
  37  *
  38  *      This function waits for any pending IRQ handlers for this interrupt
  39  *      to complete before returning. If you use this function while
  40  *      holding a resource the IRQ handler may need you will deadlock.
  41  *
  42  *      This function may be called - with care - from IRQ context.
  43  */
  44 void synchronize_irq(unsigned int irq)
  45 {
  46         struct irq_desc *desc = irq_to_desc(irq);
  47         bool inprogress;
  48
  49         if (!desc)
  50                 return;
  51
  52         do {
  53                 unsigned long flags;
  54
  55                 /*
  56                  * Wait until we're out of the critical section.  This might
  57                  * give the wrong answer due to the lack of memory barriers.
  58                  */
  59                 while (irqd_irq_inprogress(&desc->irq_data))
  60                         cpu_relax();
  61
  62                 /* Ok, that indicated we're done: double-check carefully. */
  63                 raw_spin_lock_irqsave(&desc->lock, flags);
  64                 inprogress = irqd_irq_inprogress(&desc->irq_data);
  65                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  66
  67                 /* Oops, that failed? */
  68         } while (inprogress);
  69
  70         /*
  71          * We made sure that no hardirq handler is running. Now verify
  72          * that no threaded handlers are active.
  73          */
  74         wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
  75 }
  76 EXPORT_SYMBOL(synchronize_irq);
  77
  78 #ifdef CONFIG_SMP
  79 cpumask_var_t irq_default_affinity;
  80
  81 /**
  82  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
  83  *      @irq:           Interrupt to check
  84  *
  85  */
  86 int irq_can_set_affinity(unsigned int irq)
  87 {
  88         struct irq_desc *desc = irq_to_desc(irq);
  89
  90         if (!desc || !irqd_can_balance(&desc->irq_data) ||
  91             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
  92                 return 0;
  93
  94         return 1;
  95 }
  96
  97 /**
  98  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
  99  *      @desc:          irq descriptor which has affitnity changed
 100  *
 101  *      We just set IRQTF_AFFINITY and delegate the affinity setting
 102  *      to the interrupt thread itself. We can not call
 103  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 104  *      code can be called from hard interrupt context.
 105  */
 106 void irq_set_thread_affinity(struct irq_desc *desc)
 107 {
 108         struct irqaction *action = desc->action;
 109
 110         while (action) {
 111                 if (action->thread)
 112                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
 113                 action = action->next;
 114         }
 115 }
 116
 117 #ifdef CONFIG_GENERIC_PENDING_IRQ
 118 static inline bool irq_can_move_pcntxt(struct irq_data *data)
 119 {
 120         return irqd_can_move_in_process_context(data);
 121 }
 122 static inline bool irq_move_pending(struct irq_data *data)
 123 {
 124         return irqd_is_setaffinity_pending(data);
 125 }
 126 static inline void
 127 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 128 {
 129         cpumask_copy(desc->pending_mask, mask);
 130 }
 131 static inline void
 132 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 133 {
 134         cpumask_copy(mask, desc->pending_mask);
 135 }
 136 #else
 137 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 138 static inline bool irq_move_pending(struct irq_data *data) { return false; }
 139 static inline void
 140 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 141 static inline void
 142 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 143 #endif
 144
 145 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 146                         bool force)
 147 {
 148         struct irq_desc *desc = irq_data_to_desc(data);
 149         struct irq_chip *chip = irq_data_get_irq_chip(data);
 150         int ret;
 151
 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
 161         return ret;
 162 }
 163
 164 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
 165 {
 166         struct irq_chip *chip = irq_data_get_irq_chip(data);
 167         struct irq_desc *desc = irq_data_to_desc(data);
 168         int ret = 0;
 169
 170         if (!chip || !chip->irq_set_affinity)
 171                 return -EINVAL;
 172
 173         if (irq_can_move_pcntxt(data)) {
 174                 ret = irq_do_set_affinity(data, mask, false);
 175         } else {
 176                 irqd_set_move_pending(data);
 177                 irq_copy_pending(desc, mask);
 178         }
 179
 180         if (desc->affinity_notify) {
 181                 kref_get(&desc->affinity_notify->kref);
 182                 schedule_work(&desc->affinity_notify->work);
 183         }
 184         irqd_set(data, IRQD_AFFINITY_SET);
 185
 186         return ret;
 187 }
 188
 189 /**
 190  *      irq_set_affinity - Set the irq affinity of a given irq
 191  *      @irq:           Interrupt to set affinity
 192  *      @mask:          cpumask
 193  *
 194  */
 195 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
 196 {
 197         struct irq_desc *desc = irq_to_desc(irq);
 198         unsigned long flags;
 199         int ret;
 200
 201         if (!desc)
 202                 return -EINVAL;
 203
 204         raw_spin_lock_irqsave(&desc->lock, flags);
 205         ret =  __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
 206         raw_spin_unlock_irqrestore(&desc->lock, flags);
 207         return ret;
 208 }
 209
 210 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 211 {
 212         unsigned long flags;
 213         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 214
 215         if (!desc)
 216                 return -EINVAL;
 217         desc->affinity_hint = m;
 218         irq_put_desc_unlock(desc, flags);
 219         return 0;
 220 }
 221 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 222
 223 static void irq_affinity_notify(struct work_struct *work)
 224 {
 225         struct irq_affinity_notify *notify =
 226                 container_of(work, struct irq_affinity_notify, work);
 227         struct irq_desc *desc = irq_to_desc(notify->irq);
 228         cpumask_var_t cpumask;
 229         unsigned long flags;
 230
 231         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 232                 goto out;
 233
 234         raw_spin_lock_irqsave(&desc->lock, flags);
 235         if (irq_move_pending(&desc->irq_data))
 236                 irq_get_pending(cpumask, desc);
 237         else
 238                 cpumask_copy(cpumask, desc->irq_data.affinity);
 239         raw_spin_unlock_irqrestore(&desc->lock, flags);
 240
 241         notify->notify(notify, cpumask);
 242
 243         free_cpumask_var(cpumask);
 244 out:
 245         kref_put(&notify->kref, notify->release);
 246 }
 247
 248 /**
 249  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 250  *      @irq:           Interrupt for which to enable/disable notification
 251  *      @notify:        Context for notification, or %NULL to disable
 252  *                      notification.  Function pointers must be initialised;
 253  *                      the other fields will be initialised by this function.
 254  *
 255  *      Must be called in process context.  Notification may only be enabled
 256  *      after the IRQ is allocated and must be disabled before the IRQ is
 257  *      freed using free_irq().
 258  */
 259 int
 260 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 261 {
 262         struct irq_desc *desc = irq_to_desc(irq);
 263         struct irq_affinity_notify *old_notify;
 264         unsigned long flags;
 265
 266         /* The release function is promised process context */
 267         might_sleep();
 268
 269         if (!desc)
 270                 return -EINVAL;
 271
 272         /* Complete initialisation of *notify */
 273         if (notify) {
 274                 notify->irq = irq;
 275                 kref_init(&notify->kref);
 276                 INIT_WORK(&notify->work, irq_affinity_notify);
 277         }
 278
 279         raw_spin_lock_irqsave(&desc->lock, flags);
 280         old_notify = desc->affinity_notify;
 281         desc->affinity_notify = notify;
 282         raw_spin_unlock_irqrestore(&desc->lock, flags);
 283
 284         if (old_notify)
 285                 kref_put(&old_notify->kref, old_notify->release);
 286
 287         return 0;
 288 }
 289 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 290
 291 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 292 /*
 293  * Generic version of the affinity autoselector.
 294  */
 295 static int
 296 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 297 {
 298         struct cpumask *set = irq_default_affinity;
 299         int node = desc->irq_data.node;
 300
 301         /* Excludes PER_CPU and NO_BALANCE interrupts */
 302         if (!irq_can_set_affinity(irq))
 303                 return 0;
 304
 305         /*
 306          * Preserve an userspace affinity setup, but make sure that
 307          * one of the targets is online.
 308          */
 309         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 310                 if (cpumask_intersects(desc->irq_data.affinity,
 311                                        cpu_online_mask))
 312                         set = desc->irq_data.affinity;
 313                 else
 314                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 315         }
 316
 317         cpumask_and(mask, cpu_online_mask, set);
 318         if (node != NUMA_NO_NODE) {
 319                 const struct cpumask *nodemask = cpumask_of_node(node);
 320
 321                 /* make sure at least one of the cpus in nodemask is online */
 322                 if (cpumask_intersects(mask, nodemask))
 323                         cpumask_and(mask, mask, nodemask);
 324         }
 325         irq_do_set_affinity(&desc->irq_data, mask, false);
 326         return 0;
 327 }
 328 #else
 329 static inline int
 330 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 331 {
 332         return irq_select_affinity(irq);
 333 }
 334 #endif
 335
 336 /*
 337  * Called when affinity is set via /proc/irq
 338  */
 339 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 340 {
 341         struct irq_desc *desc = irq_to_desc(irq);
 342         unsigned long flags;
 343         int ret;
 344
 345         raw_spin_lock_irqsave(&desc->lock, flags);
 346         ret = setup_affinity(irq, desc, mask);
 347         raw_spin_unlock_irqrestore(&desc->lock, flags);
 348         return ret;
 349 }
 350
 351 #else
 352 static inline int
 353 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 354 {
 355         return 0;
 356 }
 357 #endif
 358
 359 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 360 {
 361         if (suspend) {
 362                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 363                         return;
 364                 desc->istate |= IRQS_SUSPENDED;
 365         }
 366
 367         if (!desc->depth++)
 368                 irq_disable(desc);
 369 }
 370
 371 static int __disable_irq_nosync(unsigned int irq)
 372 {
 373         unsigned long flags;
 374         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 375
 376         if (!desc)
 377                 return -EINVAL;
 378         __disable_irq(desc, irq, false);
 379         irq_put_desc_busunlock(desc, flags);
 380         return 0;
 381 }
 382
 383 /**
 384  *      disable_irq_nosync - disable an irq without waiting
 385  *      @irq: Interrupt to disable
 386  *
 387  *      Disable the selected interrupt line.  Disables and Enables are
 388  *      nested.
 389  *      Unlike disable_irq(), this function does not ensure existing
 390  *      instances of the IRQ handler have completed before returning.
 391  *
 392  *      This function may be called from IRQ context.
 393  */
 394 void disable_irq_nosync(unsigned int irq)
 395 {
 396         __disable_irq_nosync(irq);
 397 }
 398 EXPORT_SYMBOL(disable_irq_nosync);
 399
 400 /**
 401  *      disable_irq - disable an irq and wait for completion
 402  *      @irq: Interrupt to disable
 403  *
 404  *      Disable the selected interrupt line.  Enables and Disables are
 405  *      nested.
 406  *      This function waits for any pending IRQ handlers for this interrupt
 407  *      to complete before returning. If you use this function while
 408  *      holding a resource the IRQ handler may need you will deadlock.
 409  *
 410  *      This function may be called - with care - from IRQ context.
 411  */
 412 void disable_irq(unsigned int irq)
 413 {
 414         if (!__disable_irq_nosync(irq))
 415                 synchronize_irq(irq);
 416 }
 417 EXPORT_SYMBOL(disable_irq);
 418
 419 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
 420 {
 421         if (resume) {
 422                 if (!(desc->istate & IRQS_SUSPENDED)) {
 423                         if (!desc->action)
 424                                 return;
 425                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
 426                                 return;
 427                         /* Pretend that it got disabled ! */
 428                         desc->depth++;
 429                 }
 430                 desc->istate &= ~IRQS_SUSPENDED;
 431         }
 432
 433         switch (desc->depth) {
 434         case 0:
 435  err_out:
 436                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 437                 break;
 438         case 1: {
 439                 if (desc->istate & IRQS_SUSPENDED)
 440                         goto err_out;
 441                 /* Prevent probing on this irq: */
 442                 irq_settings_set_noprobe(desc);
 443                 irq_enable(desc);
 444                 check_irq_resend(desc, irq);
 445                 /* fall-through */
 446         }
 447         default:
 448                 desc->depth--;
 449         }
 450 }
 451
 452 /**
 453  *      enable_irq - enable handling of an irq
 454  *      @irq: Interrupt to enable
 455  *
 456  *      Undoes the effect of one call to disable_irq().  If this
 457  *      matches the last disable, processing of interrupts on this
 458  *      IRQ line is re-enabled.
 459  *
 460  *      This function may be called from IRQ context only when
 461  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 462  */
 463 void enable_irq(unsigned int irq)
 464 {
 465         unsigned long flags;
 466         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 467
 468         if (!desc)
 469                 return;
 470         if (WARN(!desc->irq_data.chip,
 471                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 472                 goto out;
 473
 474         __enable_irq(desc, irq, false);
 475 out:
 476         irq_put_desc_busunlock(desc, flags);
 477 }
 478 EXPORT_SYMBOL(enable_irq);
 479
 480 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 481 {
 482         struct irq_desc *desc = irq_to_desc(irq);
 483         int ret = -ENXIO;
 484
 485         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 486                 return 0;
 487
 488         if (desc->irq_data.chip->irq_set_wake)
 489                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 490
 491         return ret;
 492 }
 493
 494 /**
 495  *      irq_set_irq_wake - control irq power management wakeup
 496  *      @irq:   interrupt to control
 497  *      @on:    enable/disable power management wakeup
 498  *
 499  *      Enable/disable power management wakeup mode, which is
 500  *      disabled by default.  Enables and disables must match,
 501  *      just as they match for non-wakeup mode support.
 502  *
 503  *      Wakeup mode lets this IRQ wake the system from sleep
 504  *      states like "suspend to RAM".
 505  */
 506 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 507 {
 508         unsigned long flags;
 509         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 510         int ret = 0;
 511
 512         if (!desc)
 513                 return -EINVAL;
 514
 515         /* wakeup-capable irqs can be shared between drivers that
 516          * don't need to have the same sleep mode behaviors.
 517          */
 518         if (on) {
 519                 if (desc->wake_depth++ == 0) {
 520                         ret = set_irq_wake_real(irq, on);
 521                         if (ret)
 522                                 desc->wake_depth = 0;
 523                         else
 524                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 525                 }
 526         } else {
 527                 if (desc->wake_depth == 0) {
 528                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 529                 } else if (--desc->wake_depth == 0) {
 530                         ret = set_irq_wake_real(irq, on);
 531                         if (ret)
 532                                 desc->wake_depth = 1;
 533                         else
 534                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 535                 }
 536         }
 537         irq_put_desc_busunlock(desc, flags);
 538         return ret;
 539 }
 540 EXPORT_SYMBOL(irq_set_irq_wake);
 541
 542 /*
 543  * Internal function that tells the architecture code whether a
 544  * particular irq has been exclusively allocated or is available
 545  * for driver use.
 546  */
 547 int can_request_irq(unsigned int irq, unsigned long irqflags)
 548 {
 549         unsigned long flags;
 550         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 551         int canrequest = 0;
 552
 553         if (!desc)
 554                 return 0;
 555
 556         if (irq_settings_can_request(desc)) {
 557                 if (desc->action)
 558                         if (irqflags & desc->action->flags & IRQF_SHARED)
 559                                 canrequest =1;
 560         }
 561         irq_put_desc_unlock(desc, flags);
 562         return canrequest;
 563 }
 564
 565 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 566                       unsigned long flags)
 567 {
 568         struct irq_chip *chip = desc->irq_data.chip;
 569         int ret, unmask = 0;
 570
 571         if (!chip || !chip->irq_set_type) {
 572                 /*
 573                  * IRQF_TRIGGER_* but the PIC does not support multiple
 574                  * flow-types?
 575                  */
 576                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 577                          chip ? (chip->name ? : "unknown") : "unknown");
 578                 return 0;
 579         }
 580
 581         flags &= IRQ_TYPE_SENSE_MASK;
 582
 583         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 584                 if (!irqd_irq_masked(&desc->irq_data))
 585                         mask_irq(desc);
 586                 if (!irqd_irq_disabled(&desc->irq_data))
 587                         unmask = 1;
 588         }
 589
 590         /* caller masked out all except trigger mode flags */
 591         ret = chip->irq_set_type(&desc->irq_data, flags);
 592
 593         switch (ret) {
 594         case IRQ_SET_MASK_OK:
 595                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 596                 irqd_set(&desc->irq_data, flags);
 597
 598         case IRQ_SET_MASK_OK_NOCOPY:
 599                 flags = irqd_get_trigger_type(&desc->irq_data);
 600                 irq_settings_set_trigger_mask(desc, flags);
 601                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 602                 irq_settings_clr_level(desc);
 603                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 604                         irq_settings_set_level(desc);
 605                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 606                 }
 607
 608                 ret = 0;
 609                 break;
 610         default:
 611                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 612                        flags, irq, chip->irq_set_type);
 613         }
 614         if (unmask)
 615                 unmask_irq(desc);
 616         return ret;
 617 }
 618
 619 /*
 620  * Default primary interrupt handler for threaded interrupts. Is
 621  * assigned as primary handler when request_threaded_irq is called
 622  * with handler == NULL. Useful for oneshot interrupts.
 623  */
 624 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 625 {
 626         return IRQ_WAKE_THREAD;
 627 }
 628
 629 /*
 630  * Primary handler for nested threaded interrupts. Should never be
 631  * called.
 632  */
 633 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 634 {
 635         WARN(1, "Primary handler called for nested irq %d\n", irq);
 636         return IRQ_NONE;
 637 }
 638
 639 static int irq_wait_for_interrupt(struct irqaction *action)
 640 {
 641         set_current_state(TASK_INTERRUPTIBLE);
 642
 643         while (!kthread_should_stop()) {
 644
 645                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 646                                        &action->thread_flags)) {
 647                         __set_current_state(TASK_RUNNING);
 648                         return 0;
 649                 }
 650                 schedule();
 651                 set_current_state(TASK_INTERRUPTIBLE);
 652         }
 653         __set_current_state(TASK_RUNNING);
 654         return -1;
 655 }
 656
 657 /*
 658  * Oneshot interrupts keep the irq line masked until the threaded
 659  * handler finished. unmask if the interrupt has not been disabled and
 660  * is marked MASKED.
 661  */
 662 static void irq_finalize_oneshot(struct irq_desc *desc,
 663                                  struct irqaction *action)
 664 {
 665         if (!(desc->istate & IRQS_ONESHOT))
 666                 return;
 667 again:
 668         chip_bus_lock(desc);
 669         raw_spin_lock_irq(&desc->lock);
 670
 671         /*
 672          * Implausible though it may be we need to protect us against
 673          * the following scenario:
 674          *
 675          * The thread is faster done than the hard interrupt handler
 676          * on the other CPU. If we unmask the irq line then the
 677          * interrupt can come in again and masks the line, leaves due
 678          * to IRQS_INPROGRESS and the irq line is masked forever.
 679          *
 680          * This also serializes the state of shared oneshot handlers
 681          * versus "desc->threads_onehsot |= action->thread_mask;" in
 682          * irq_wake_thread(). See the comment there which explains the
 683          * serialization.
 684          */
 685         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 686                 raw_spin_unlock_irq(&desc->lock);
 687                 chip_bus_sync_unlock(desc);
 688                 cpu_relax();
 689                 goto again;
 690         }
 691
 692         /*
 693          * Now check again, whether the thread should run. Otherwise
 694          * we would clear the threads_oneshot bit of this thread which
 695          * was just set.
 696          */
 697         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 698                 goto out_unlock;
 699
 700         desc->threads_oneshot &= ~action->thread_mask;
 701
 702         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 703             irqd_irq_masked(&desc->irq_data))
 704                 unmask_irq(desc);
 705
 706 out_unlock:
 707         raw_spin_unlock_irq(&desc->lock);
 708         chip_bus_sync_unlock(desc);
 709 }
 710
 711 #ifdef CONFIG_SMP
 712 /*
 713  * Check whether we need to chasnge the affinity of the interrupt thread.
 714  */
 715 static void
 716 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 717 {
 718         cpumask_var_t mask;
 719
 720         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 721                 return;
 722
 723         /*
 724          * In case we are out of memory we set IRQTF_AFFINITY again and
 725          * try again next time
 726          */
 727         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 728                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 729                 return;
 730         }
 731
 732         raw_spin_lock_irq(&desc->lock);
 733         cpumask_copy(mask, desc->irq_data.affinity);
 734         raw_spin_unlock_irq(&desc->lock);
 735
 736         set_cpus_allowed_ptr(current, mask);
 737         free_cpumask_var(mask);
 738 }
 739 #else
 740 static inline void
 741 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 742 #endif
 743
 744 /*
 745  * Interrupts which are not explicitely requested as threaded
 746  * interrupts rely on the implicit bh/preempt disable of the hard irq
 747  * context. So we need to disable bh here to avoid deadlocks and other
 748  * side effects.
 749  */
 750 static irqreturn_t
 751 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 752 {
 753         irqreturn_t ret;
 754
 755         local_bh_disable();
 756         ret = action->thread_fn(action->irq, action->dev_id);
 757         irq_finalize_oneshot(desc, action);
 758         local_bh_enable();
 759         return ret;
 760 }
 761
 762 /*
 763  * Interrupts explicitely requested as threaded interupts want to be
 764  * preemtible - many of them need to sleep and wait for slow busses to
 765  * complete.
 766  */
 767 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 768                 struct irqaction *action)
 769 {
 770         irqreturn_t ret;
 771
 772         ret = action->thread_fn(action->irq, action->dev_id);
 773         irq_finalize_oneshot(desc, action);
 774         return ret;
 775 }
 776
 777 static void wake_threads_waitq(struct irq_desc *desc)
 778 {
 779         if (atomic_dec_and_test(&desc->threads_active) &&
 780             waitqueue_active(&desc->wait_for_threads))
 781                 wake_up(&desc->wait_for_threads);
 782 }
 783
 784 static void irq_thread_dtor(struct task_work *unused)
 785 {
 786         struct task_struct *tsk = current;
 787         struct irq_desc *desc;
 788         struct irqaction *action;
 789
 790         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 791                 return;
 792
 793         action = kthread_data(tsk);
 794
 795         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 796                tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
 797
 798
 799         desc = irq_to_desc(action->irq);
 800         /*
 801          * If IRQTF_RUNTHREAD is set, we need to decrement
 802          * desc->threads_active and wake possible waiters.
 803          */
 804         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 805                 wake_threads_waitq(desc);
 806
 807         /* Prevent a stale desc->threads_oneshot */
 808         irq_finalize_oneshot(desc, action);
 809 }
 810
 811 /*
 812  * Interrupt handler thread
 813  */
 814 static int irq_thread(void *data)
 815 {
 816         struct task_work on_exit_work;
 817         static const struct sched_param param = {
 818                 .sched_priority = MAX_USER_RT_PRIO/2,
 819         };
 820         struct irqaction *action = data;
 821         struct irq_desc *desc = irq_to_desc(action->irq);
 822         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 823                         struct irqaction *action);
 824
 825         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 826                                         &action->thread_flags))
 827                 handler_fn = irq_forced_thread_fn;
 828         else
 829                 handler_fn = irq_thread_fn;
 830
 831         sched_setscheduler(current, SCHED_FIFO, &param);
 832
 833         init_task_work(&on_exit_work, irq_thread_dtor, NULL);
 834         task_work_add(current, &on_exit_work, false);
 835
 836         while (!irq_wait_for_interrupt(action)) {
 837                 irqreturn_t action_ret;
 838
 839                 irq_thread_check_affinity(desc, action);
 840
 841                 action_ret = handler_fn(desc, action);
 842                 if (!noirqdebug)
 843                         note_interrupt(action->irq, desc, action_ret);
 844
 845                 wake_threads_waitq(desc);
 846         }
 847
 848         /*
 849          * This is the regular exit path. __free_irq() is stopping the
 850          * thread via kthread_stop() after calling
 851          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 852          * oneshot mask bit can be set. We cannot verify that as we
 853          * cannot touch the oneshot mask at this point anymore as
 854          * __setup_irq() might have given out currents thread_mask
 855          * again.
 856          */
 857         task_work_cancel(current, irq_thread_dtor);
 858         return 0;
 859 }
 860
 861 static void irq_setup_forced_threading(struct irqaction *new)
 862 {
 863         if (!force_irqthreads)
 864                 return;
 865         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 866                 return;
 867
 868         new->flags |= IRQF_ONESHOT;
 869
 870         if (!new->thread_fn) {
 871                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 872                 new->thread_fn = new->handler;
 873                 new->handler = irq_default_primary_handler;
 874         }
 875 }
 876
 877 /*
 878  * Internal function to register an irqaction - typically used to
 879  * allocate special interrupts that are part of the architecture.
 880  */
 881 static int
 882 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 883 {
 884         struct irqaction *old, **old_ptr;
 885         unsigned long flags, thread_mask = 0;
 886         int ret, nested, shared = 0;
 887         cpumask_var_t mask;
 888
 889         if (!desc)
 890                 return -EINVAL;
 891
 892         if (desc->irq_data.chip == &no_irq_chip)
 893                 return -ENOSYS;
 894         if (!try_module_get(desc->owner))
 895                 return -ENODEV;
 896         /*
 897          * Some drivers like serial.c use request_irq() heavily,
 898          * so we have to be careful not to interfere with a
 899          * running system.
 900          */
 901         if (new->flags & IRQF_SAMPLE_RANDOM) {
 902                 /*
 903                  * This function might sleep, we want to call it first,
 904                  * outside of the atomic block.
 905                  * Yes, this might clear the entropy pool if the wrong
 906                  * driver is attempted to be loaded, without actually
 907                  * installing a new handler, but is this really a problem,
 908                  * only the sysadmin is able to do this.
 909                  */
 910                 rand_initialize_irq(irq);
 911         }
 912
 913         /*
 914          * Check whether the interrupt nests into another interrupt
 915          * thread.
 916          */
 917         nested = irq_settings_is_nested_thread(desc);
 918         if (nested) {
 919                 if (!new->thread_fn) {
 920                         ret = -EINVAL;
 921                         goto out_mput;
 922                 }
 923                 /*
 924                  * Replace the primary handler which was provided from
 925                  * the driver for non nested interrupt handling by the
 926                  * dummy function which warns when called.
 927                  */
 928                 new->handler = irq_nested_primary_handler;
 929         } else {
 930                 if (irq_settings_can_thread(desc))
 931                         irq_setup_forced_threading(new);
 932         }
 933
 934         /*
 935          * Create a handler thread when a thread function is supplied
 936          * and the interrupt does not nest into another interrupt
 937          * thread.
 938          */
 939         if (new->thread_fn && !nested) {
 940                 struct task_struct *t;
 941
 942                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
 943                                    new->name);
 944                 if (IS_ERR(t)) {
 945                         ret = PTR_ERR(t);
 946                         goto out_mput;
 947                 }
 948                 /*
 949                  * We keep the reference to the task struct even if
 950                  * the thread dies to avoid that the interrupt code
 951                  * references an already freed task_struct.
 952                  */
 953                 get_task_struct(t);
 954                 new->thread = t;
 955         }
 956
 957         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 958                 ret = -ENOMEM;
 959                 goto out_thread;
 960         }
 961
 962         /*
 963          * The following block of code has to be executed atomically
 964          */
 965         raw_spin_lock_irqsave(&desc->lock, flags);
 966         old_ptr = &desc->action;
 967         old = *old_ptr;
 968         if (old) {
 969                 /*
 970                  * Can't share interrupts unless both agree to and are
 971                  * the same type (level, edge, polarity). So both flag
 972                  * fields must have IRQF_SHARED set and the bits which
 973                  * set the trigger type must match. Also all must
 974                  * agree on ONESHOT.
 975                  */
 976                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
 977                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
 978                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
 979                         goto mismatch;
 980
 981                 /* All handlers must agree on per-cpuness */
 982                 if ((old->flags & IRQF_PERCPU) !=
 983                     (new->flags & IRQF_PERCPU))
 984                         goto mismatch;
 985
 986                 /* add new interrupt at end of irq queue */
 987                 do {
 988                         /*
 989                          * Or all existing action->thread_mask bits,
 990                          * so we can find the next zero bit for this
 991                          * new action.
 992                          */
 993                         thread_mask |= old->thread_mask;
 994                         old_ptr = &old->next;
 995                         old = *old_ptr;
 996                 } while (old);
 997                 shared = 1;
 998         }
 999
1000         /*
1001          * Setup the thread mask for this irqaction for ONESHOT. For
1002          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1003          * conditional in irq_wake_thread().
1004          */
1005         if (new->flags & IRQF_ONESHOT) {
1006                 /*
1007                  * Unlikely to have 32 resp 64 irqs sharing one line,
1008                  * but who knows.
1009                  */
1010                 if (thread_mask == ~0UL) {
1011                         ret = -EBUSY;
1012                         goto out_mask;
1013                 }
1014                 /*
1015                  * The thread_mask for the action is or'ed to
1016                  * desc->thread_active to indicate that the
1017                  * IRQF_ONESHOT thread handler has been woken, but not
1018                  * yet finished. The bit is cleared when a thread
1019                  * completes. When all threads of a shared interrupt
1020                  * line have completed desc->threads_active becomes
1021                  * zero and the interrupt line is unmasked. See
1022                  * handle.c:irq_wake_thread() for further information.
1023                  *
1024                  * If no thread is woken by primary (hard irq context)
1025                  * interrupt handlers, then desc->threads_active is
1026                  * also checked for zero to unmask the irq line in the
1027                  * affected hard irq flow handlers
1028                  * (handle_[fasteoi|level]_irq).
1029                  *
1030                  * The new action gets the first zero bit of
1031                  * thread_mask assigned. See the loop above which or's
1032                  * all existing action->thread_mask bits.
1033                  */
1034                 new->thread_mask = 1 << ffz(thread_mask);
1035
1036         } else if (new->handler == irq_default_primary_handler) {
1037                 /*
1038                  * The interrupt was requested with handler = NULL, so
1039                  * we use the default primary handler for it. But it
1040                  * does not have the oneshot flag set. In combination
1041                  * with level interrupts this is deadly, because the
1042                  * default primary handler just wakes the thread, then
1043                  * the irq lines is reenabled, but the device still
1044                  * has the level irq asserted. Rinse and repeat....
1045                  *
1046                  * While this works for edge type interrupts, we play
1047                  * it safe and reject unconditionally because we can't
1048                  * say for sure which type this interrupt really
1049                  * has. The type flags are unreliable as the
1050                  * underlying chip implementation can override them.
1051                  */
1052                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1053                        irq);
1054                 ret = -EINVAL;
1055                 goto out_mask;
1056         }
1057
1058         if (!shared) {
1059                 init_waitqueue_head(&desc->wait_for_threads);
1060
1061                 /* Setup the type (level, edge polarity) if configured: */
1062                 if (new->flags & IRQF_TRIGGER_MASK) {
1063                         ret = __irq_set_trigger(desc, irq,
1064                                         new->flags & IRQF_TRIGGER_MASK);
1065
1066                         if (ret)
1067                                 goto out_mask;
1068                 }
1069
1070                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1071                                   IRQS_ONESHOT | IRQS_WAITING);
1072                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1073
1074                 if (new->flags & IRQF_PERCPU) {
1075                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1076                         irq_settings_set_per_cpu(desc);
1077                 }
1078
1079                 if (new->flags & IRQF_ONESHOT)
1080                         desc->istate |= IRQS_ONESHOT;
1081
1082                 if (irq_settings_can_autoenable(desc))
1083                         irq_startup(desc, true);
1084                 else
1085                         /* Undo nested disables: */
1086                         desc->depth = 1;
1087
1088                 /* Exclude IRQ from balancing if requested */
1089                 if (new->flags & IRQF_NOBALANCING) {
1090                         irq_settings_set_no_balancing(desc);
1091                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1092                 }
1093
1094                 /* Set default affinity mask once everything is setup */
1095                 setup_affinity(irq, desc, mask);
1096
1097         } else if (new->flags & IRQF_TRIGGER_MASK) {
1098                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1099                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1100
1101                 if (nmsk != omsk)
1102                         /* hope the handler works with current  trigger mode */
1103                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1104                                    irq, nmsk, omsk);
1105         }
1106
1107         new->irq = irq;
1108         *old_ptr = new;
1109
1110         /* Reset broken irq detection when installing new handler */
1111         desc->irq_count = 0;
1112         desc->irqs_unhandled = 0;
1113
1114         /*
1115          * Check whether we disabled the irq via the spurious handler
1116          * before. Reenable it and give it another chance.
1117          */
1118         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1119                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1120                 __enable_irq(desc, irq, false);
1121         }
1122
1123         raw_spin_unlock_irqrestore(&desc->lock, flags);
1124
1125         /*
1126          * Strictly no need to wake it up, but hung_task complains
1127          * when no hard interrupt wakes the thread up.
1128          */
1129         if (new->thread)
1130                 wake_up_process(new->thread);
1131
1132         register_irq_proc(irq, desc);
1133         new->dir = NULL;
1134         register_handler_proc(irq, new);
1135         free_cpumask_var(mask);
1136
1137         return 0;
1138
1139 mismatch:
1140         if (!(new->flags & IRQF_PROBE_SHARED)) {
1141                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1142                        irq, new->flags, new->name, old->flags, old->name);
1143 #ifdef CONFIG_DEBUG_SHIRQ
1144                 dump_stack();
1145 #endif
1146         }
1147         ret = -EBUSY;
1148
1149 out_mask:
1150         raw_spin_unlock_irqrestore(&desc->lock, flags);
1151         free_cpumask_var(mask);
1152
1153 out_thread:
1154         if (new->thread) {
1155                 struct task_struct *t = new->thread;
1156
1157                 new->thread = NULL;
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         raw_spin_lock_irqsave(&desc->lock, flags);
1204
1205         /*
1206          * There can be multiple actions per IRQ descriptor, find the right
1207          * one based on the dev_id:
1208          */
1209         action_ptr = &desc->action;
1210         for (;;) {
1211                 action = *action_ptr;
1212
1213                 if (!action) {
1214                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1215                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1216
1217                         return NULL;
1218                 }
1219
1220                 if (action->dev_id == dev_id)
1221                         break;
1222                 action_ptr = &action->next;
1223         }
1224
1225         /* Found it - now remove it from the list of entries: */
1226         *action_ptr = action->next;
1227
1228         /* If this was the last handler, shut down the IRQ line: */
1229         if (!desc->action)
1230                 irq_shutdown(desc);
1231
1232 #ifdef CONFIG_SMP
1233         /* make sure affinity_hint is cleaned up */
1234         if (WARN_ON_ONCE(desc->affinity_hint))
1235                 desc->affinity_hint = NULL;
1236 #endif
1237
1238         raw_spin_unlock_irqrestore(&desc->lock, flags);
1239
1240         unregister_handler_proc(irq, action);
1241
1242         /* Make sure it's not being used on another CPU: */
1243         synchronize_irq(irq);
1244
1245 #ifdef CONFIG_DEBUG_SHIRQ
1246         /*
1247          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1248          * event to happen even now it's being freed, so let's make sure that
1249          * is so by doing an extra call to the handler ....
1250          *
1251          * ( We do this after actually deregistering it, to make sure that a
1252          *   'real' IRQ doesn't run in * parallel with our fake. )
1253          */
1254         if (action->flags & IRQF_SHARED) {
1255                 local_irq_save(flags);
1256                 action->handler(irq, dev_id);
1257                 local_irq_restore(flags);
1258         }
1259 #endif
1260
1261         if (action->thread) {
1262                 kthread_stop(action->thread);
1263                 put_task_struct(action->thread);
1264         }
1265
1266         module_put(desc->owner);
1267         return action;
1268 }
1269
1270 /**
1271  *      remove_irq - free an interrupt
1272  *      @irq: Interrupt line to free
1273  *      @act: irqaction for the interrupt
1274  *
1275  * Used to remove interrupts statically setup by the early boot process.
1276  */
1277 void remove_irq(unsigned int irq, struct irqaction *act)
1278 {
1279         struct irq_desc *desc = irq_to_desc(irq);
1280
1281         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1282             __free_irq(irq, act->dev_id);
1283 }
1284 EXPORT_SYMBOL_GPL(remove_irq);
1285
1286 /**
1287  *      free_irq - free an interrupt allocated with request_irq
1288  *      @irq: Interrupt line to free
1289  *      @dev_id: Device identity to free
1290  *
1291  *      Remove an interrupt handler. The handler is removed and if the
1292  *      interrupt line is no longer in use by any driver it is disabled.
1293  *      On a shared IRQ the caller must ensure the interrupt is disabled
1294  *      on the card it drives before calling this function. The function
1295  *      does not return until any executing interrupts for this IRQ
1296  *      have completed.
1297  *
1298  *      This function must not be called from interrupt context.
1299  */
1300 void free_irq(unsigned int irq, void *dev_id)
1301 {
1302         struct irq_desc *desc = irq_to_desc(irq);
1303
1304         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1305                 return;
1306
1307 #ifdef CONFIG_SMP
1308         if (WARN_ON(desc->affinity_notify))
1309                 desc->affinity_notify = NULL;
1310 #endif
1311
1312         chip_bus_lock(desc);
1313         kfree(__free_irq(irq, dev_id));
1314         chip_bus_sync_unlock(desc);
1315 }
1316 EXPORT_SYMBOL(free_irq);
1317
1318 /**
1319  *      request_threaded_irq - allocate an interrupt line
1320  *      @irq: Interrupt line to allocate
1321  *      @handler: Function to be called when the IRQ occurs.
1322  *                Primary handler for threaded interrupts
1323  *                If NULL and thread_fn != NULL the default
1324  *                primary handler is installed
1325  *      @thread_fn: Function called from the irq handler thread
1326  *                  If NULL, no irq thread is created
1327  *      @irqflags: Interrupt type flags
1328  *      @devname: An ascii name for the claiming device
1329  *      @dev_id: A cookie passed back to the handler function
1330  *
1331  *      This call allocates interrupt resources and enables the
1332  *      interrupt line and IRQ handling. From the point this
1333  *      call is made your handler function may be invoked. Since
1334  *      your handler function must clear any interrupt the board
1335  *      raises, you must take care both to initialise your hardware
1336  *      and to set up the interrupt handler in the right order.
1337  *
1338  *      If you want to set up a threaded irq handler for your device
1339  *      then you need to supply @handler and @thread_fn. @handler is
1340  *      still called in hard interrupt context and has to check
1341  *      whether the interrupt originates from the device. If yes it
1342  *      needs to disable the interrupt on the device and return
1343  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1344  *      @thread_fn. This split handler design is necessary to support
1345  *      shared interrupts.
1346  *
1347  *      Dev_id must be globally unique. Normally the address of the
1348  *      device data structure is used as the cookie. Since the handler
1349  *      receives this value it makes sense to use it.
1350  *
1351  *      If your interrupt is shared you must pass a non NULL dev_id
1352  *      as this is required when freeing the interrupt.
1353  *
1354  *      Flags:
1355  *
1356  *      IRQF_SHARED             Interrupt is shared
1357  *      IRQF_SAMPLE_RANDOM      The interrupt can be used for entropy
1358  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1359  *
1360  */
1361 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1362                          irq_handler_t thread_fn, unsigned long irqflags,
1363                          const char *devname, void *dev_id)
1364 {
1365         struct irqaction *action;
1366         struct irq_desc *desc;
1367         int retval;
1368
1369         /*
1370          * Sanity-check: shared interrupts must pass in a real dev-ID,
1371          * otherwise we'll have trouble later trying to figure out
1372          * which interrupt is which (messes up the interrupt freeing
1373          * logic etc).
1374          */
1375         if ((irqflags & IRQF_SHARED) && !dev_id)
1376                 return -EINVAL;
1377
1378         desc = irq_to_desc(irq);
1379         if (!desc)
1380                 return -EINVAL;
1381
1382         if (!irq_settings_can_request(desc) ||
1383             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1384                 return -EINVAL;
1385
1386         if (!handler) {
1387                 if (!thread_fn)
1388                         return -EINVAL;
1389                 handler = irq_default_primary_handler;
1390         }
1391
1392         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1393         if (!action)
1394                 return -ENOMEM;
1395
1396         action->handler = handler;
1397         action->thread_fn = thread_fn;
1398         action->flags = irqflags;
1399         action->name = devname;
1400         action->dev_id = dev_id;
1401
1402         chip_bus_lock(desc);
1403         retval = __setup_irq(irq, desc, action);
1404         chip_bus_sync_unlock(desc);
1405
1406         if (retval)
1407                 kfree(action);
1408
1409 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1410         if (!retval && (irqflags & IRQF_SHARED)) {
1411                 /*
1412                  * It's a shared IRQ -- the driver ought to be prepared for it
1413                  * to happen immediately, so let's make sure....
1414                  * We disable the irq to make sure that a 'real' IRQ doesn't
1415                  * run in parallel with our fake.
1416                  */
1417                 unsigned long flags;
1418
1419                 disable_irq(irq);
1420                 local_irq_save(flags);
1421
1422                 handler(irq, dev_id);
1423
1424                 local_irq_restore(flags);
1425                 enable_irq(irq);
1426         }
1427 #endif
1428         return retval;
1429 }
1430 EXPORT_SYMBOL(request_threaded_irq);
1431
1432 /**
1433  *      request_any_context_irq - allocate an interrupt line
1434  *      @irq: Interrupt line to allocate
1435  *      @handler: Function to be called when the IRQ occurs.
1436  *                Threaded handler for threaded interrupts.
1437  *      @flags: Interrupt type flags
1438  *      @name: An ascii name for the claiming device
1439  *      @dev_id: A cookie passed back to the handler function
1440  *
1441  *      This call allocates interrupt resources and enables the
1442  *      interrupt line and IRQ handling. It selects either a
1443  *      hardirq or threaded handling method depending on the
1444  *      context.
1445  *
1446  *      On failure, it returns a negative value. On success,
1447  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1448  */
1449 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1450                             unsigned long flags, const char *name, void *dev_id)
1451 {
1452         struct irq_desc *desc = irq_to_desc(irq);
1453         int ret;
1454
1455         if (!desc)
1456                 return -EINVAL;
1457
1458         if (irq_settings_is_nested_thread(desc)) {
1459                 ret = request_threaded_irq(irq, NULL, handler,
1460                                            flags, name, dev_id);
1461                 return !ret ? IRQC_IS_NESTED : ret;
1462         }
1463
1464         ret = request_irq(irq, handler, flags, name, dev_id);
1465         return !ret ? IRQC_IS_HARDIRQ : ret;
1466 }
1467 EXPORT_SYMBOL_GPL(request_any_context_irq);
1468
1469 void enable_percpu_irq(unsigned int irq, unsigned int type)
1470 {
1471         unsigned int cpu = smp_processor_id();
1472         unsigned long flags;
1473         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1474
1475         if (!desc)
1476                 return;
1477
1478         type &= IRQ_TYPE_SENSE_MASK;
1479         if (type != IRQ_TYPE_NONE) {
1480                 int ret;
1481
1482                 ret = __irq_set_trigger(desc, irq, type);
1483
1484                 if (ret) {
1485                         WARN(1, "failed to set type for IRQ%d\n", irq);
1486                         goto out;
1487                 }
1488         }
1489
1490         irq_percpu_enable(desc, cpu);
1491 out:
1492         irq_put_desc_unlock(desc, flags);
1493 }
1494
1495 void disable_percpu_irq(unsigned int irq)
1496 {
1497         unsigned int cpu = smp_processor_id();
1498         unsigned long flags;
1499         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1500
1501         if (!desc)
1502                 return;
1503
1504         irq_percpu_disable(desc, cpu);
1505         irq_put_desc_unlock(desc, flags);
1506 }
1507
1508 /*
1509  * Internal function to unregister a percpu irqaction.
1510  */
1511 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1512 {
1513         struct irq_desc *desc = irq_to_desc(irq);
1514         struct irqaction *action;
1515         unsigned long flags;
1516
1517         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1518
1519         if (!desc)
1520                 return NULL;
1521
1522         raw_spin_lock_irqsave(&desc->lock, flags);
1523
1524         action = desc->action;
1525         if (!action || action->percpu_dev_id != dev_id) {
1526                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1527                 goto bad;
1528         }
1529
1530         if (!cpumask_empty(desc->percpu_enabled)) {
1531                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1532                      irq, cpumask_first(desc->percpu_enabled));
1533                 goto bad;
1534         }
1535
1536         /* Found it - now remove it from the list of entries: */
1537         desc->action = NULL;
1538
1539         raw_spin_unlock_irqrestore(&desc->lock, flags);
1540
1541         unregister_handler_proc(irq, action);
1542
1543         module_put(desc->owner);
1544         return action;
1545
1546 bad:
1547         raw_spin_unlock_irqrestore(&desc->lock, flags);
1548         return NULL;
1549 }
1550
1551 /**
1552  *      remove_percpu_irq - free a per-cpu interrupt
1553  *      @irq: Interrupt line to free
1554  *      @act: irqaction for the interrupt
1555  *
1556  * Used to remove interrupts statically setup by the early boot process.
1557  */
1558 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1559 {
1560         struct irq_desc *desc = irq_to_desc(irq);
1561
1562         if (desc && irq_settings_is_per_cpu_devid(desc))
1563             __free_percpu_irq(irq, act->percpu_dev_id);
1564 }
1565
1566 /**
1567  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1568  *      @irq: Interrupt line to free
1569  *      @dev_id: Device identity to free
1570  *
1571  *      Remove a percpu interrupt handler. The handler is removed, but
1572  *      the interrupt line is not disabled. This must be done on each
1573  *      CPU before calling this function. The function does not return
1574  *      until any executing interrupts for this IRQ have completed.
1575  *
1576  *      This function must not be called from interrupt context.
1577  */
1578 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1579 {
1580         struct irq_desc *desc = irq_to_desc(irq);
1581
1582         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1583                 return;
1584
1585         chip_bus_lock(desc);
1586         kfree(__free_percpu_irq(irq, dev_id));
1587         chip_bus_sync_unlock(desc);
1588 }
1589
1590 /**
1591  *      setup_percpu_irq - setup a per-cpu interrupt
1592  *      @irq: Interrupt line to setup
1593  *      @act: irqaction for the interrupt
1594  *
1595  * Used to statically setup per-cpu interrupts in the early boot process.
1596  */
1597 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1598 {
1599         struct irq_desc *desc = irq_to_desc(irq);
1600         int retval;
1601
1602         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1603                 return -EINVAL;
1604         chip_bus_lock(desc);
1605         retval = __setup_irq(irq, desc, act);
1606         chip_bus_sync_unlock(desc);
1607
1608         return retval;
1609 }
1610
1611 /**
1612  *      request_percpu_irq - allocate a percpu interrupt line
1613  *      @irq: Interrupt line to allocate
1614  *      @handler: Function to be called when the IRQ occurs.
1615  *      @devname: An ascii name for the claiming device
1616  *      @dev_id: A percpu cookie passed back to the handler function
1617  *
1618  *      This call allocates interrupt resources, but doesn't
1619  *      automatically enable the interrupt. It has to be done on each
1620  *      CPU using enable_percpu_irq().
1621  *
1622  *      Dev_id must be globally unique. It is a per-cpu variable, and
1623  *      the handler gets called with the interrupted CPU's instance of
1624  *      that variable.
1625  */
1626 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1627                        const char *devname, void __percpu *dev_id)
1628 {
1629         struct irqaction *action;
1630         struct irq_desc *desc;
1631         int retval;
1632
1633         if (!dev_id)
1634                 return -EINVAL;
1635
1636         desc = irq_to_desc(irq);
1637         if (!desc || !irq_settings_can_request(desc) ||
1638             !irq_settings_is_per_cpu_devid(desc))
1639                 return -EINVAL;
1640
1641         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1642         if (!action)
1643                 return -ENOMEM;
1644
1645         action->handler = handler;
1646         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1647         action->name = devname;
1648         action->percpu_dev_id = dev_id;
1649
1650         chip_bus_lock(desc);
1651         retval = __setup_irq(irq, desc, action);
1652         chip_bus_sync_unlock(desc);
1653
1654         if (retval)
1655                 kfree(action);
1656
1657         return retval;
1658 }