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/sched/rt.h>
  20 #include <linux/task_work.h>
  21
  22 #include "internals.h"
  23
  24 #ifdef CONFIG_IRQ_FORCED_THREADING
  25 __read_mostly bool force_irqthreads;
  26
  27 static int __init setup_forced_irqthreads(char *arg)
  28 {
  29         force_irqthreads = true;
  30         return 0;
  31 }
  32 early_param("threadirqs", setup_forced_irqthreads);
  33 #endif
  34
  35 static void __synchronize_hardirq(struct irq_desc *desc)
  36 {
  37         bool inprogress;
  38
  39         do {
  40                 unsigned long flags;
  41
  42                 /*
  43                  * Wait until we're out of the critical section.  This might
  44                  * give the wrong answer due to the lack of memory barriers.
  45                  */
  46                 while (irqd_irq_inprogress(&desc->irq_data))
  47                         cpu_relax();
  48
  49                 /* Ok, that indicated we're done: double-check carefully. */
  50                 raw_spin_lock_irqsave(&desc->lock, flags);
  51                 inprogress = irqd_irq_inprogress(&desc->irq_data);
  52                 raw_spin_unlock_irqrestore(&desc->lock, flags);
  53
  54                 /* Oops, that failed? */
  55         } while (inprogress);
  56 }
  57
  58 /**
  59  *      synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
  60  *      @irq: interrupt number to wait for
  61  *
  62  *      This function waits for any pending hard IRQ handlers for this
  63  *      interrupt to complete before returning. If you use this
  64  *      function while holding a resource the IRQ handler may need you
  65  *      will deadlock. It does not take associated threaded handlers
  66  *      into account.
  67  *
  68  *      Do not use this for shutdown scenarios where you must be sure
  69  *      that all parts (hardirq and threaded handler) have completed.
  70  *
  71  *      This function may be called - with care - from IRQ context.
  72  */
  73 void synchronize_hardirq(unsigned int irq)
  74 {
  75         struct irq_desc *desc = irq_to_desc(irq);
  76
  77         if (desc)
  78                 __synchronize_hardirq(desc);
  79 }
  80 EXPORT_SYMBOL(synchronize_hardirq);
  81
  82 /**
  83  *      synchronize_irq - wait for pending IRQ handlers (on other CPUs)
  84  *      @irq: interrupt number to wait for
  85  *
  86  *      This function waits for any pending IRQ handlers for this interrupt
  87  *      to complete before returning. If you use this function while
  88  *      holding a resource the IRQ handler may need you will deadlock.
  89  *
  90  *      This function may be called - with care - from IRQ context.
  91  */
  92 void synchronize_irq(unsigned int irq)
  93 {
  94         struct irq_desc *desc = irq_to_desc(irq);
  95
  96         if (desc) {
  97                 __synchronize_hardirq(desc);
  98                 /*
  99                  * We made sure that no hardirq handler is
 100                  * running. Now verify that no threaded handlers are
 101                  * active.
 102                  */
 103                 wait_event(desc->wait_for_threads,
 104                            !atomic_read(&desc->threads_active));
 105         }
 106 }
 107 EXPORT_SYMBOL(synchronize_irq);
 108
 109 #ifdef CONFIG_SMP
 110 cpumask_var_t irq_default_affinity;
 111
 112 /**
 113  *      irq_can_set_affinity - Check if the affinity of a given irq can be set
 114  *      @irq:           Interrupt to check
 115  *
 116  */
 117 int irq_can_set_affinity(unsigned int irq)
 118 {
 119         struct irq_desc *desc = irq_to_desc(irq);
 120
 121         if (!desc || !irqd_can_balance(&desc->irq_data) ||
 122             !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
 123                 return 0;
 124
 125         return 1;
 126 }
 127
 128 /**
 129  *      irq_set_thread_affinity - Notify irq threads to adjust affinity
 130  *      @desc:          irq descriptor which has affitnity changed
 131  *
 132  *      We just set IRQTF_AFFINITY and delegate the affinity setting
 133  *      to the interrupt thread itself. We can not call
 134  *      set_cpus_allowed_ptr() here as we hold desc->lock and this
 135  *      code can be called from hard interrupt context.
 136  */
 137 void irq_set_thread_affinity(struct irq_desc *desc)
 138 {
 139         struct irqaction *action = desc->action;
 140
 141         while (action) {
 142                 if (action->thread)
 143                         set_bit(IRQTF_AFFINITY, &action->thread_flags);
 144                 action = action->next;
 145         }
 146 }
 147
 148 #ifdef CONFIG_GENERIC_PENDING_IRQ
 149 static inline bool irq_can_move_pcntxt(struct irq_data *data)
 150 {
 151         return irqd_can_move_in_process_context(data);
 152 }
 153 static inline bool irq_move_pending(struct irq_data *data)
 154 {
 155         return irqd_is_setaffinity_pending(data);
 156 }
 157 static inline void
 158 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
 159 {
 160         cpumask_copy(desc->pending_mask, mask);
 161 }
 162 static inline void
 163 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
 164 {
 165         cpumask_copy(mask, desc->pending_mask);
 166 }
 167 #else
 168 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
 169 static inline bool irq_move_pending(struct irq_data *data) { return false; }
 170 static inline void
 171 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
 172 static inline void
 173 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
 174 #endif
 175
 176 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 177                         bool force)
 178 {
 179         struct irq_desc *desc = irq_data_to_desc(data);
 180         struct irq_chip *chip = irq_data_get_irq_chip(data);
 181         int ret;
 182
 183         ret = chip->irq_set_affinity(data, mask, force);
 184         switch (ret) {
 185         case IRQ_SET_MASK_OK:
 186                 cpumask_copy(data->affinity, mask);
 187         case IRQ_SET_MASK_OK_NOCOPY:
 188                 irq_set_thread_affinity(desc);
 189                 ret = 0;
 190         }
 191
 192         return ret;
 193 }
 194
 195 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
 196                             bool force)
 197 {
 198         struct irq_chip *chip = irq_data_get_irq_chip(data);
 199         struct irq_desc *desc = irq_data_to_desc(data);
 200         int ret = 0;
 201
 202         if (!chip || !chip->irq_set_affinity)
 203                 return -EINVAL;
 204
 205         if (irq_can_move_pcntxt(data)) {
 206                 ret = irq_do_set_affinity(data, mask, force);
 207         } else {
 208                 irqd_set_move_pending(data);
 209                 irq_copy_pending(desc, mask);
 210         }
 211
 212         if (desc->affinity_notify) {
 213                 kref_get(&desc->affinity_notify->kref);
 214                 schedule_work(&desc->affinity_notify->work);
 215         }
 216         irqd_set(data, IRQD_AFFINITY_SET);
 217
 218         return ret;
 219 }
 220
 221 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
 222 {
 223         struct irq_desc *desc = irq_to_desc(irq);
 224         unsigned long flags;
 225         int ret;
 226
 227         if (!desc)
 228                 return -EINVAL;
 229
 230         raw_spin_lock_irqsave(&desc->lock, flags);
 231         ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
 232         raw_spin_unlock_irqrestore(&desc->lock, flags);
 233         return ret;
 234 }
 235
 236 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
 237 {
 238         unsigned long flags;
 239         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 240
 241         if (!desc)
 242                 return -EINVAL;
 243         desc->affinity_hint = m;
 244         irq_put_desc_unlock(desc, flags);
 245         return 0;
 246 }
 247 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
 248
 249 static void irq_affinity_notify(struct work_struct *work)
 250 {
 251         struct irq_affinity_notify *notify =
 252                 container_of(work, struct irq_affinity_notify, work);
 253         struct irq_desc *desc = irq_to_desc(notify->irq);
 254         cpumask_var_t cpumask;
 255         unsigned long flags;
 256
 257         if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
 258                 goto out;
 259
 260         raw_spin_lock_irqsave(&desc->lock, flags);
 261         if (irq_move_pending(&desc->irq_data))
 262                 irq_get_pending(cpumask, desc);
 263         else
 264                 cpumask_copy(cpumask, desc->irq_data.affinity);
 265         raw_spin_unlock_irqrestore(&desc->lock, flags);
 266
 267         notify->notify(notify, cpumask);
 268
 269         free_cpumask_var(cpumask);
 270 out:
 271         kref_put(&notify->kref, notify->release);
 272 }
 273
 274 /**
 275  *      irq_set_affinity_notifier - control notification of IRQ affinity changes
 276  *      @irq:           Interrupt for which to enable/disable notification
 277  *      @notify:        Context for notification, or %NULL to disable
 278  *                      notification.  Function pointers must be initialised;
 279  *                      the other fields will be initialised by this function.
 280  *
 281  *      Must be called in process context.  Notification may only be enabled
 282  *      after the IRQ is allocated and must be disabled before the IRQ is
 283  *      freed using free_irq().
 284  */
 285 int
 286 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 287 {
 288         struct irq_desc *desc = irq_to_desc(irq);
 289         struct irq_affinity_notify *old_notify;
 290         unsigned long flags;
 291
 292         /* The release function is promised process context */
 293         might_sleep();
 294
 295         if (!desc)
 296                 return -EINVAL;
 297
 298         /* Complete initialisation of *notify */
 299         if (notify) {
 300                 notify->irq = irq;
 301                 kref_init(&notify->kref);
 302                 INIT_WORK(&notify->work, irq_affinity_notify);
 303         }
 304
 305         raw_spin_lock_irqsave(&desc->lock, flags);
 306         old_notify = desc->affinity_notify;
 307         desc->affinity_notify = notify;
 308         raw_spin_unlock_irqrestore(&desc->lock, flags);
 309
 310         if (old_notify)
 311                 kref_put(&old_notify->kref, old_notify->release);
 312
 313         return 0;
 314 }
 315 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
 316
 317 #ifndef CONFIG_AUTO_IRQ_AFFINITY
 318 /*
 319  * Generic version of the affinity autoselector.
 320  */
 321 static int
 322 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 323 {
 324         struct cpumask *set = irq_default_affinity;
 325         int node = desc->irq_data.node;
 326
 327         /* Excludes PER_CPU and NO_BALANCE interrupts */
 328         if (!irq_can_set_affinity(irq))
 329                 return 0;
 330
 331         /*
 332          * Preserve an userspace affinity setup, but make sure that
 333          * one of the targets is online.
 334          */
 335         if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
 336                 if (cpumask_intersects(desc->irq_data.affinity,
 337                                        cpu_online_mask))
 338                         set = desc->irq_data.affinity;
 339                 else
 340                         irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
 341         }
 342
 343         cpumask_and(mask, cpu_online_mask, set);
 344         if (node != NUMA_NO_NODE) {
 345                 const struct cpumask *nodemask = cpumask_of_node(node);
 346
 347                 /* make sure at least one of the cpus in nodemask is online */
 348                 if (cpumask_intersects(mask, nodemask))
 349                         cpumask_and(mask, mask, nodemask);
 350         }
 351         irq_do_set_affinity(&desc->irq_data, mask, false);
 352         return 0;
 353 }
 354 #else
 355 static inline int
 356 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
 357 {
 358         return irq_select_affinity(irq);
 359 }
 360 #endif
 361
 362 /*
 363  * Called when affinity is set via /proc/irq
 364  */
 365 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
 366 {
 367         struct irq_desc *desc = irq_to_desc(irq);
 368         unsigned long flags;
 369         int ret;
 370
 371         raw_spin_lock_irqsave(&desc->lock, flags);
 372         ret = setup_affinity(irq, desc, mask);
 373         raw_spin_unlock_irqrestore(&desc->lock, flags);
 374         return ret;
 375 }
 376
 377 #else
 378 static inline int
 379 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
 380 {
 381         return 0;
 382 }
 383 #endif
 384
 385 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
 386 {
 387         if (suspend) {
 388                 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
 389                         return;
 390                 desc->istate |= IRQS_SUSPENDED;
 391         }
 392
 393         if (!desc->depth++)
 394                 irq_disable(desc);
 395 }
 396
 397 static int __disable_irq_nosync(unsigned int irq)
 398 {
 399         unsigned long flags;
 400         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 401
 402         if (!desc)
 403                 return -EINVAL;
 404         __disable_irq(desc, irq, false);
 405         irq_put_desc_busunlock(desc, flags);
 406         return 0;
 407 }
 408
 409 /**
 410  *      disable_irq_nosync - disable an irq without waiting
 411  *      @irq: Interrupt to disable
 412  *
 413  *      Disable the selected interrupt line.  Disables and Enables are
 414  *      nested.
 415  *      Unlike disable_irq(), this function does not ensure existing
 416  *      instances of the IRQ handler have completed before returning.
 417  *
 418  *      This function may be called from IRQ context.
 419  */
 420 void disable_irq_nosync(unsigned int irq)
 421 {
 422         __disable_irq_nosync(irq);
 423 }
 424 EXPORT_SYMBOL(disable_irq_nosync);
 425
 426 /**
 427  *      disable_irq - disable an irq and wait for completion
 428  *      @irq: Interrupt to disable
 429  *
 430  *      Disable the selected interrupt line.  Enables and Disables are
 431  *      nested.
 432  *      This function waits for any pending IRQ handlers for this interrupt
 433  *      to complete before returning. If you use this function while
 434  *      holding a resource the IRQ handler may need you will deadlock.
 435  *
 436  *      This function may be called - with care - from IRQ context.
 437  */
 438 void disable_irq(unsigned int irq)
 439 {
 440         if (!__disable_irq_nosync(irq))
 441                 synchronize_irq(irq);
 442 }
 443 EXPORT_SYMBOL(disable_irq);
 444
 445 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
 446 {
 447         if (resume) {
 448                 if (!(desc->istate & IRQS_SUSPENDED)) {
 449                         if (!desc->action)
 450                                 return;
 451                         if (!(desc->action->flags & IRQF_FORCE_RESUME))
 452                                 return;
 453                         /* Pretend that it got disabled ! */
 454                         desc->depth++;
 455                 }
 456                 desc->istate &= ~IRQS_SUSPENDED;
 457         }
 458
 459         switch (desc->depth) {
 460         case 0:
 461  err_out:
 462                 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
 463                 break;
 464         case 1: {
 465                 if (desc->istate & IRQS_SUSPENDED)
 466                         goto err_out;
 467                 /* Prevent probing on this irq: */
 468                 irq_settings_set_noprobe(desc);
 469                 irq_enable(desc);
 470                 check_irq_resend(desc, irq);
 471                 /* fall-through */
 472         }
 473         default:
 474                 desc->depth--;
 475         }
 476 }
 477
 478 /**
 479  *      enable_irq - enable handling of an irq
 480  *      @irq: Interrupt to enable
 481  *
 482  *      Undoes the effect of one call to disable_irq().  If this
 483  *      matches the last disable, processing of interrupts on this
 484  *      IRQ line is re-enabled.
 485  *
 486  *      This function may be called from IRQ context only when
 487  *      desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
 488  */
 489 void enable_irq(unsigned int irq)
 490 {
 491         unsigned long flags;
 492         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 493
 494         if (!desc)
 495                 return;
 496         if (WARN(!desc->irq_data.chip,
 497                  KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
 498                 goto out;
 499
 500         __enable_irq(desc, irq, false);
 501 out:
 502         irq_put_desc_busunlock(desc, flags);
 503 }
 504 EXPORT_SYMBOL(enable_irq);
 505
 506 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 507 {
 508         struct irq_desc *desc = irq_to_desc(irq);
 509         int ret = -ENXIO;
 510
 511         if (irq_desc_get_chip(desc)->flags &  IRQCHIP_SKIP_SET_WAKE)
 512                 return 0;
 513
 514         if (desc->irq_data.chip->irq_set_wake)
 515                 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
 516
 517         return ret;
 518 }
 519
 520 /**
 521  *      irq_set_irq_wake - control irq power management wakeup
 522  *      @irq:   interrupt to control
 523  *      @on:    enable/disable power management wakeup
 524  *
 525  *      Enable/disable power management wakeup mode, which is
 526  *      disabled by default.  Enables and disables must match,
 527  *      just as they match for non-wakeup mode support.
 528  *
 529  *      Wakeup mode lets this IRQ wake the system from sleep
 530  *      states like "suspend to RAM".
 531  */
 532 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 533 {
 534         unsigned long flags;
 535         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
 536         int ret = 0;
 537
 538         if (!desc)
 539                 return -EINVAL;
 540
 541         /* wakeup-capable irqs can be shared between drivers that
 542          * don't need to have the same sleep mode behaviors.
 543          */
 544         if (on) {
 545                 if (desc->wake_depth++ == 0) {
 546                         ret = set_irq_wake_real(irq, on);
 547                         if (ret)
 548                                 desc->wake_depth = 0;
 549                         else
 550                                 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
 551                 }
 552         } else {
 553                 if (desc->wake_depth == 0) {
 554                         WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
 555                 } else if (--desc->wake_depth == 0) {
 556                         ret = set_irq_wake_real(irq, on);
 557                         if (ret)
 558                                 desc->wake_depth = 1;
 559                         else
 560                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
 561                 }
 562         }
 563         irq_put_desc_busunlock(desc, flags);
 564         return ret;
 565 }
 566 EXPORT_SYMBOL(irq_set_irq_wake);
 567
 568 /*
 569  * Internal function that tells the architecture code whether a
 570  * particular irq has been exclusively allocated or is available
 571  * for driver use.
 572  */
 573 int can_request_irq(unsigned int irq, unsigned long irqflags)
 574 {
 575         unsigned long flags;
 576         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 577         int canrequest = 0;
 578
 579         if (!desc)
 580                 return 0;
 581
 582         if (irq_settings_can_request(desc)) {
 583                 if (!desc->action ||
 584                     irqflags & desc->action->flags & IRQF_SHARED)
 585                         canrequest = 1;
 586         }
 587         irq_put_desc_unlock(desc, flags);
 588         return canrequest;
 589 }
 590
 591 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 592                       unsigned long flags)
 593 {
 594         struct irq_chip *chip = desc->irq_data.chip;
 595         int ret, unmask = 0;
 596
 597         if (!chip || !chip->irq_set_type) {
 598                 /*
 599                  * IRQF_TRIGGER_* but the PIC does not support multiple
 600                  * flow-types?
 601                  */
 602                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
 603                          chip ? (chip->name ? : "unknown") : "unknown");
 604                 return 0;
 605         }
 606
 607         flags &= IRQ_TYPE_SENSE_MASK;
 608
 609         if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
 610                 if (!irqd_irq_masked(&desc->irq_data))
 611                         mask_irq(desc);
 612                 if (!irqd_irq_disabled(&desc->irq_data))
 613                         unmask = 1;
 614         }
 615
 616         /* caller masked out all except trigger mode flags */
 617         ret = chip->irq_set_type(&desc->irq_data, flags);
 618
 619         switch (ret) {
 620         case IRQ_SET_MASK_OK:
 621                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
 622                 irqd_set(&desc->irq_data, flags);
 623
 624         case IRQ_SET_MASK_OK_NOCOPY:
 625                 flags = irqd_get_trigger_type(&desc->irq_data);
 626                 irq_settings_set_trigger_mask(desc, flags);
 627                 irqd_clear(&desc->irq_data, IRQD_LEVEL);
 628                 irq_settings_clr_level(desc);
 629                 if (flags & IRQ_TYPE_LEVEL_MASK) {
 630                         irq_settings_set_level(desc);
 631                         irqd_set(&desc->irq_data, IRQD_LEVEL);
 632                 }
 633
 634                 ret = 0;
 635                 break;
 636         default:
 637                 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
 638                        flags, irq, chip->irq_set_type);
 639         }
 640         if (unmask)
 641                 unmask_irq(desc);
 642         return ret;
 643 }
 644
 645 #ifdef CONFIG_HARDIRQS_SW_RESEND
 646 int irq_set_parent(int irq, int parent_irq)
 647 {
 648         unsigned long flags;
 649         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
 650
 651         if (!desc)
 652                 return -EINVAL;
 653
 654         desc->parent_irq = parent_irq;
 655
 656         irq_put_desc_unlock(desc, flags);
 657         return 0;
 658 }
 659 #endif
 660
 661 /*
 662  * Default primary interrupt handler for threaded interrupts. Is
 663  * assigned as primary handler when request_threaded_irq is called
 664  * with handler == NULL. Useful for oneshot interrupts.
 665  */
 666 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
 667 {
 668         return IRQ_WAKE_THREAD;
 669 }
 670
 671 /*
 672  * Primary handler for nested threaded interrupts. Should never be
 673  * called.
 674  */
 675 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
 676 {
 677         WARN(1, "Primary handler called for nested irq %d\n", irq);
 678         return IRQ_NONE;
 679 }
 680
 681 static int irq_wait_for_interrupt(struct irqaction *action)
 682 {
 683         set_current_state(TASK_INTERRUPTIBLE);
 684
 685         while (!kthread_should_stop()) {
 686
 687                 if (test_and_clear_bit(IRQTF_RUNTHREAD,
 688                                        &action->thread_flags)) {
 689                         __set_current_state(TASK_RUNNING);
 690                         return 0;
 691                 }
 692                 schedule();
 693                 set_current_state(TASK_INTERRUPTIBLE);
 694         }
 695         __set_current_state(TASK_RUNNING);
 696         return -1;
 697 }
 698
 699 /*
 700  * Oneshot interrupts keep the irq line masked until the threaded
 701  * handler finished. unmask if the interrupt has not been disabled and
 702  * is marked MASKED.
 703  */
 704 static void irq_finalize_oneshot(struct irq_desc *desc,
 705                                  struct irqaction *action)
 706 {
 707         if (!(desc->istate & IRQS_ONESHOT))
 708                 return;
 709 again:
 710         chip_bus_lock(desc);
 711         raw_spin_lock_irq(&desc->lock);
 712
 713         /*
 714          * Implausible though it may be we need to protect us against
 715          * the following scenario:
 716          *
 717          * The thread is faster done than the hard interrupt handler
 718          * on the other CPU. If we unmask the irq line then the
 719          * interrupt can come in again and masks the line, leaves due
 720          * to IRQS_INPROGRESS and the irq line is masked forever.
 721          *
 722          * This also serializes the state of shared oneshot handlers
 723          * versus "desc->threads_onehsot |= action->thread_mask;" in
 724          * irq_wake_thread(). See the comment there which explains the
 725          * serialization.
 726          */
 727         if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
 728                 raw_spin_unlock_irq(&desc->lock);
 729                 chip_bus_sync_unlock(desc);
 730                 cpu_relax();
 731                 goto again;
 732         }
 733
 734         /*
 735          * Now check again, whether the thread should run. Otherwise
 736          * we would clear the threads_oneshot bit of this thread which
 737          * was just set.
 738          */
 739         if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 740                 goto out_unlock;
 741
 742         desc->threads_oneshot &= ~action->thread_mask;
 743
 744         if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
 745             irqd_irq_masked(&desc->irq_data))
 746                 unmask_threaded_irq(desc);
 747
 748 out_unlock:
 749         raw_spin_unlock_irq(&desc->lock);
 750         chip_bus_sync_unlock(desc);
 751 }
 752
 753 #ifdef CONFIG_SMP
 754 /*
 755  * Check whether we need to change the affinity of the interrupt thread.
 756  */
 757 static void
 758 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
 759 {
 760         cpumask_var_t mask;
 761         bool valid = true;
 762
 763         if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
 764                 return;
 765
 766         /*
 767          * In case we are out of memory we set IRQTF_AFFINITY again and
 768          * try again next time
 769          */
 770         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
 771                 set_bit(IRQTF_AFFINITY, &action->thread_flags);
 772                 return;
 773         }
 774
 775         raw_spin_lock_irq(&desc->lock);
 776         /*
 777          * This code is triggered unconditionally. Check the affinity
 778          * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
 779          */
 780         if (desc->irq_data.affinity)
 781                 cpumask_copy(mask, desc->irq_data.affinity);
 782         else
 783                 valid = false;
 784         raw_spin_unlock_irq(&desc->lock);
 785
 786         if (valid)
 787                 set_cpus_allowed_ptr(current, mask);
 788         free_cpumask_var(mask);
 789 }
 790 #else
 791 static inline void
 792 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
 793 #endif
 794
 795 /*
 796  * Interrupts which are not explicitely requested as threaded
 797  * interrupts rely on the implicit bh/preempt disable of the hard irq
 798  * context. So we need to disable bh here to avoid deadlocks and other
 799  * side effects.
 800  */
 801 static irqreturn_t
 802 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
 803 {
 804         irqreturn_t ret;
 805
 806         local_bh_disable();
 807         ret = action->thread_fn(action->irq, action->dev_id);
 808         irq_finalize_oneshot(desc, action);
 809         local_bh_enable();
 810         return ret;
 811 }
 812
 813 /*
 814  * Interrupts explicitly requested as threaded interrupts want to be
 815  * preemtible - many of them need to sleep and wait for slow busses to
 816  * complete.
 817  */
 818 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
 819                 struct irqaction *action)
 820 {
 821         irqreturn_t ret;
 822
 823         ret = action->thread_fn(action->irq, action->dev_id);
 824         irq_finalize_oneshot(desc, action);
 825         return ret;
 826 }
 827
 828 static void wake_threads_waitq(struct irq_desc *desc)
 829 {
 830         if (atomic_dec_and_test(&desc->threads_active))
 831                 wake_up(&desc->wait_for_threads);
 832 }
 833
 834 static void irq_thread_dtor(struct callback_head *unused)
 835 {
 836         struct task_struct *tsk = current;
 837         struct irq_desc *desc;
 838         struct irqaction *action;
 839
 840         if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
 841                 return;
 842
 843         action = kthread_data(tsk);
 844
 845         pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
 846                tsk->comm, tsk->pid, action->irq);
 847
 848
 849         desc = irq_to_desc(action->irq);
 850         /*
 851          * If IRQTF_RUNTHREAD is set, we need to decrement
 852          * desc->threads_active and wake possible waiters.
 853          */
 854         if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
 855                 wake_threads_waitq(desc);
 856
 857         /* Prevent a stale desc->threads_oneshot */
 858         irq_finalize_oneshot(desc, action);
 859 }
 860
 861 /*
 862  * Interrupt handler thread
 863  */
 864 static int irq_thread(void *data)
 865 {
 866         struct callback_head on_exit_work;
 867         struct irqaction *action = data;
 868         struct irq_desc *desc = irq_to_desc(action->irq);
 869         irqreturn_t (*handler_fn)(struct irq_desc *desc,
 870                         struct irqaction *action);
 871
 872         if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
 873                                         &action->thread_flags))
 874                 handler_fn = irq_forced_thread_fn;
 875         else
 876                 handler_fn = irq_thread_fn;
 877
 878         init_task_work(&on_exit_work, irq_thread_dtor);
 879         task_work_add(current, &on_exit_work, false);
 880
 881         irq_thread_check_affinity(desc, action);
 882
 883         while (!irq_wait_for_interrupt(action)) {
 884                 irqreturn_t action_ret;
 885
 886                 irq_thread_check_affinity(desc, action);
 887
 888                 action_ret = handler_fn(desc, action);
 889                 if (!noirqdebug)
 890                         note_interrupt(action->irq, desc, action_ret);
 891
 892                 wake_threads_waitq(desc);
 893         }
 894
 895         /*
 896          * This is the regular exit path. __free_irq() is stopping the
 897          * thread via kthread_stop() after calling
 898          * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
 899          * oneshot mask bit can be set. We cannot verify that as we
 900          * cannot touch the oneshot mask at this point anymore as
 901          * __setup_irq() might have given out currents thread_mask
 902          * again.
 903          */
 904         task_work_cancel(current, irq_thread_dtor);
 905         return 0;
 906 }
 907
 908 /**
 909  *      irq_wake_thread - wake the irq thread for the action identified by dev_id
 910  *      @irq:           Interrupt line
 911  *      @dev_id:        Device identity for which the thread should be woken
 912  *
 913  */
 914 void irq_wake_thread(unsigned int irq, void *dev_id)
 915 {
 916         struct irq_desc *desc = irq_to_desc(irq);
 917         struct irqaction *action;
 918         unsigned long flags;
 919
 920         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
 921                 return;
 922
 923         raw_spin_lock_irqsave(&desc->lock, flags);
 924         for (action = desc->action; action; action = action->next) {
 925                 if (action->dev_id == dev_id) {
 926                         if (action->thread)
 927                                 __irq_wake_thread(desc, action);
 928                         break;
 929                 }
 930         }
 931         raw_spin_unlock_irqrestore(&desc->lock, flags);
 932 }
 933 EXPORT_SYMBOL_GPL(irq_wake_thread);
 934
 935 static void irq_setup_forced_threading(struct irqaction *new)
 936 {
 937         if (!force_irqthreads)
 938                 return;
 939         if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
 940                 return;
 941
 942         new->flags |= IRQF_ONESHOT;
 943
 944         if (!new->thread_fn) {
 945                 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
 946                 new->thread_fn = new->handler;
 947                 new->handler = irq_default_primary_handler;
 948         }
 949 }
 950
 951 static int irq_request_resources(struct irq_desc *desc)
 952 {
 953         struct irq_data *d = &desc->irq_data;
 954         struct irq_chip *c = d->chip;
 955
 956         return c->irq_request_resources ? c->irq_request_resources(d) : 0;
 957 }
 958
 959 static void irq_release_resources(struct irq_desc *desc)
 960 {
 961         struct irq_data *d = &desc->irq_data;
 962         struct irq_chip *c = d->chip;
 963
 964         if (c->irq_release_resources)
 965                 c->irq_release_resources(d);
 966 }
 967
 968 /*
 969  * Internal function to register an irqaction - typically used to
 970  * allocate special interrupts that are part of the architecture.
 971  */
 972 static int
 973 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 974 {
 975         struct irqaction *old, **old_ptr;
 976         unsigned long flags, thread_mask = 0;
 977         int ret, nested, shared = 0;
 978         cpumask_var_t mask;
 979
 980         if (!desc)
 981                 return -EINVAL;
 982
 983         if (desc->irq_data.chip == &no_irq_chip)
 984                 return -ENOSYS;
 985         if (!try_module_get(desc->owner))
 986                 return -ENODEV;
 987
 988         /*
 989          * Check whether the interrupt nests into another interrupt
 990          * thread.
 991          */
 992         nested = irq_settings_is_nested_thread(desc);
 993         if (nested) {
 994                 if (!new->thread_fn) {
 995                         ret = -EINVAL;
 996                         goto out_mput;
 997                 }
 998                 /*
 999                  * Replace the primary handler which was provided from
1000                  * the driver for non nested interrupt handling by the
1001                  * dummy function which warns when called.
1002                  */
1003                 new->handler = irq_nested_primary_handler;
1004         } else {
1005                 if (irq_settings_can_thread(desc))
1006                         irq_setup_forced_threading(new);
1007         }
1008
1009         /*
1010          * Create a handler thread when a thread function is supplied
1011          * and the interrupt does not nest into another interrupt
1012          * thread.
1013          */
1014         if (new->thread_fn && !nested) {
1015                 struct task_struct *t;
1016                 static const struct sched_param param = {
1017                         .sched_priority = MAX_USER_RT_PRIO/2,
1018                 };
1019
1020                 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1021                                    new->name);
1022                 if (IS_ERR(t)) {
1023                         ret = PTR_ERR(t);
1024                         goto out_mput;
1025                 }
1026
1027                 sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
1028
1029                 /*
1030                  * We keep the reference to the task struct even if
1031                  * the thread dies to avoid that the interrupt code
1032                  * references an already freed task_struct.
1033                  */
1034                 get_task_struct(t);
1035                 new->thread = t;
1036                 /*
1037                  * Tell the thread to set its affinity. This is
1038                  * important for shared interrupt handlers as we do
1039                  * not invoke setup_affinity() for the secondary
1040                  * handlers as everything is already set up. Even for
1041                  * interrupts marked with IRQF_NO_BALANCE this is
1042                  * correct as we want the thread to move to the cpu(s)
1043                  * on which the requesting code placed the interrupt.
1044                  */
1045                 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1046         }
1047
1048         if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1049                 ret = -ENOMEM;
1050                 goto out_thread;
1051         }
1052
1053         /*
1054          * Drivers are often written to work w/o knowledge about the
1055          * underlying irq chip implementation, so a request for a
1056          * threaded irq without a primary hard irq context handler
1057          * requires the ONESHOT flag to be set. Some irq chips like
1058          * MSI based interrupts are per se one shot safe. Check the
1059          * chip flags, so we can avoid the unmask dance at the end of
1060          * the threaded handler for those.
1061          */
1062         if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1063                 new->flags &= ~IRQF_ONESHOT;
1064
1065         /*
1066          * The following block of code has to be executed atomically
1067          */
1068         raw_spin_lock_irqsave(&desc->lock, flags);
1069         old_ptr = &desc->action;
1070         old = *old_ptr;
1071         if (old) {
1072                 /*
1073                  * Can't share interrupts unless both agree to and are
1074                  * the same type (level, edge, polarity). So both flag
1075                  * fields must have IRQF_SHARED set and the bits which
1076                  * set the trigger type must match. Also all must
1077                  * agree on ONESHOT.
1078                  */
1079                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1080                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1081                     ((old->flags ^ new->flags) & IRQF_ONESHOT))
1082                         goto mismatch;
1083
1084                 /* All handlers must agree on per-cpuness */
1085                 if ((old->flags & IRQF_PERCPU) !=
1086                     (new->flags & IRQF_PERCPU))
1087                         goto mismatch;
1088
1089                 /* add new interrupt at end of irq queue */
1090                 do {
1091                         /*
1092                          * Or all existing action->thread_mask bits,
1093                          * so we can find the next zero bit for this
1094                          * new action.
1095                          */
1096                         thread_mask |= old->thread_mask;
1097                         old_ptr = &old->next;
1098                         old = *old_ptr;
1099                 } while (old);
1100                 shared = 1;
1101         }
1102
1103         /*
1104          * Setup the thread mask for this irqaction for ONESHOT. For
1105          * !ONESHOT irqs the thread mask is 0 so we can avoid a
1106          * conditional in irq_wake_thread().
1107          */
1108         if (new->flags & IRQF_ONESHOT) {
1109                 /*
1110                  * Unlikely to have 32 resp 64 irqs sharing one line,
1111                  * but who knows.
1112                  */
1113                 if (thread_mask == ~0UL) {
1114                         ret = -EBUSY;
1115                         goto out_mask;
1116                 }
1117                 /*
1118                  * The thread_mask for the action is or'ed to
1119                  * desc->thread_active to indicate that the
1120                  * IRQF_ONESHOT thread handler has been woken, but not
1121                  * yet finished. The bit is cleared when a thread
1122                  * completes. When all threads of a shared interrupt
1123                  * line have completed desc->threads_active becomes
1124                  * zero and the interrupt line is unmasked. See
1125                  * handle.c:irq_wake_thread() for further information.
1126                  *
1127                  * If no thread is woken by primary (hard irq context)
1128                  * interrupt handlers, then desc->threads_active is
1129                  * also checked for zero to unmask the irq line in the
1130                  * affected hard irq flow handlers
1131                  * (handle_[fasteoi|level]_irq).
1132                  *
1133                  * The new action gets the first zero bit of
1134                  * thread_mask assigned. See the loop above which or's
1135                  * all existing action->thread_mask bits.
1136                  */
1137                 new->thread_mask = 1 << ffz(thread_mask);
1138
1139         } else if (new->handler == irq_default_primary_handler &&
1140                    !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1141                 /*
1142                  * The interrupt was requested with handler = NULL, so
1143                  * we use the default primary handler for it. But it
1144                  * does not have the oneshot flag set. In combination
1145                  * with level interrupts this is deadly, because the
1146                  * default primary handler just wakes the thread, then
1147                  * the irq lines is reenabled, but the device still
1148                  * has the level irq asserted. Rinse and repeat....
1149                  *
1150                  * While this works for edge type interrupts, we play
1151                  * it safe and reject unconditionally because we can't
1152                  * say for sure which type this interrupt really
1153                  * has. The type flags are unreliable as the
1154                  * underlying chip implementation can override them.
1155                  */
1156                 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1157                        irq);
1158                 ret = -EINVAL;
1159                 goto out_mask;
1160         }
1161
1162         if (!shared) {
1163                 ret = irq_request_resources(desc);
1164                 if (ret) {
1165                         pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1166                                new->name, irq, desc->irq_data.chip->name);
1167                         goto out_mask;
1168                 }
1169
1170                 init_waitqueue_head(&desc->wait_for_threads);
1171
1172                 /* Setup the type (level, edge polarity) if configured: */
1173                 if (new->flags & IRQF_TRIGGER_MASK) {
1174                         ret = __irq_set_trigger(desc, irq,
1175                                         new->flags & IRQF_TRIGGER_MASK);
1176
1177                         if (ret)
1178                                 goto out_mask;
1179                 }
1180
1181                 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1182                                   IRQS_ONESHOT | IRQS_WAITING);
1183                 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1184
1185                 if (new->flags & IRQF_PERCPU) {
1186                         irqd_set(&desc->irq_data, IRQD_PER_CPU);
1187                         irq_settings_set_per_cpu(desc);
1188                 }
1189
1190                 if (new->flags & IRQF_ONESHOT)
1191                         desc->istate |= IRQS_ONESHOT;
1192
1193                 if (irq_settings_can_autoenable(desc))
1194                         irq_startup(desc, true);
1195                 else
1196                         /* Undo nested disables: */
1197                         desc->depth = 1;
1198
1199                 /* Exclude IRQ from balancing if requested */
1200                 if (new->flags & IRQF_NOBALANCING) {
1201                         irq_settings_set_no_balancing(desc);
1202                         irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1203                 }
1204
1205                 /* Set default affinity mask once everything is setup */
1206                 setup_affinity(irq, desc, mask);
1207
1208         } else if (new->flags & IRQF_TRIGGER_MASK) {
1209                 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1210                 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1211
1212                 if (nmsk != omsk)
1213                         /* hope the handler works with current  trigger mode */
1214                         pr_warning("irq %d uses trigger mode %u; requested %u\n",
1215                                    irq, nmsk, omsk);
1216         }
1217
1218         new->irq = irq;
1219         *old_ptr = new;
1220
1221         /* Reset broken irq detection when installing new handler */
1222         desc->irq_count = 0;
1223         desc->irqs_unhandled = 0;
1224
1225         /*
1226          * Check whether we disabled the irq via the spurious handler
1227          * before. Reenable it and give it another chance.
1228          */
1229         if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1230                 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1231                 __enable_irq(desc, irq, false);
1232         }
1233
1234         raw_spin_unlock_irqrestore(&desc->lock, flags);
1235
1236         /*
1237          * Strictly no need to wake it up, but hung_task complains
1238          * when no hard interrupt wakes the thread up.
1239          */
1240         if (new->thread)
1241                 wake_up_process(new->thread);
1242
1243         register_irq_proc(irq, desc);
1244         new->dir = NULL;
1245         register_handler_proc(irq, new);
1246         free_cpumask_var(mask);
1247
1248         return 0;
1249
1250 mismatch:
1251         if (!(new->flags & IRQF_PROBE_SHARED)) {
1252                 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1253                        irq, new->flags, new->name, old->flags, old->name);
1254 #ifdef CONFIG_DEBUG_SHIRQ
1255                 dump_stack();
1256 #endif
1257         }
1258         ret = -EBUSY;
1259
1260 out_mask:
1261         raw_spin_unlock_irqrestore(&desc->lock, flags);
1262         free_cpumask_var(mask);
1263
1264 out_thread:
1265         if (new->thread) {
1266                 struct task_struct *t = new->thread;
1267
1268                 new->thread = NULL;
1269                 kthread_stop(t);
1270                 put_task_struct(t);
1271         }
1272 out_mput:
1273         module_put(desc->owner);
1274         return ret;
1275 }
1276
1277 /**
1278  *      setup_irq - setup an interrupt
1279  *      @irq: Interrupt line to setup
1280  *      @act: irqaction for the interrupt
1281  *
1282  * Used to statically setup interrupts in the early boot process.
1283  */
1284 int setup_irq(unsigned int irq, struct irqaction *act)
1285 {
1286         int retval;
1287         struct irq_desc *desc = irq_to_desc(irq);
1288
1289         if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1290                 return -EINVAL;
1291         chip_bus_lock(desc);
1292         retval = __setup_irq(irq, desc, act);
1293         chip_bus_sync_unlock(desc);
1294
1295         return retval;
1296 }
1297 EXPORT_SYMBOL_GPL(setup_irq);
1298
1299 /*
1300  * Internal function to unregister an irqaction - used to free
1301  * regular and special interrupts that are part of the architecture.
1302  */
1303 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1304 {
1305         struct irq_desc *desc = irq_to_desc(irq);
1306         struct irqaction *action, **action_ptr;
1307         unsigned long flags;
1308
1309         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1310
1311         if (!desc)
1312                 return NULL;
1313
1314         raw_spin_lock_irqsave(&desc->lock, flags);
1315
1316         /*
1317          * There can be multiple actions per IRQ descriptor, find the right
1318          * one based on the dev_id:
1319          */
1320         action_ptr = &desc->action;
1321         for (;;) {
1322                 action = *action_ptr;
1323
1324                 if (!action) {
1325                         WARN(1, "Trying to free already-free IRQ %d\n", irq);
1326                         raw_spin_unlock_irqrestore(&desc->lock, flags);
1327
1328                         return NULL;
1329                 }
1330
1331                 if (action->dev_id == dev_id)
1332                         break;
1333                 action_ptr = &action->next;
1334         }
1335
1336         /* Found it - now remove it from the list of entries: */
1337         *action_ptr = action->next;
1338
1339         /* If this was the last handler, shut down the IRQ line: */
1340         if (!desc->action) {
1341                 irq_shutdown(desc);
1342                 irq_release_resources(desc);
1343         }
1344
1345 #ifdef CONFIG_SMP
1346         /* make sure affinity_hint is cleaned up */
1347         if (WARN_ON_ONCE(desc->affinity_hint))
1348                 desc->affinity_hint = NULL;
1349 #endif
1350
1351         raw_spin_unlock_irqrestore(&desc->lock, flags);
1352
1353         unregister_handler_proc(irq, action);
1354
1355         /* Make sure it's not being used on another CPU: */
1356         synchronize_irq(irq);
1357
1358 #ifdef CONFIG_DEBUG_SHIRQ
1359         /*
1360          * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1361          * event to happen even now it's being freed, so let's make sure that
1362          * is so by doing an extra call to the handler ....
1363          *
1364          * ( We do this after actually deregistering it, to make sure that a
1365          *   'real' IRQ doesn't run in * parallel with our fake. )
1366          */
1367         if (action->flags & IRQF_SHARED) {
1368                 local_irq_save(flags);
1369                 action->handler(irq, dev_id);
1370                 local_irq_restore(flags);
1371         }
1372 #endif
1373
1374         if (action->thread) {
1375                 kthread_stop(action->thread);
1376                 put_task_struct(action->thread);
1377         }
1378
1379         module_put(desc->owner);
1380         return action;
1381 }
1382
1383 /**
1384  *      remove_irq - free an interrupt
1385  *      @irq: Interrupt line to free
1386  *      @act: irqaction for the interrupt
1387  *
1388  * Used to remove interrupts statically setup by the early boot process.
1389  */
1390 void remove_irq(unsigned int irq, struct irqaction *act)
1391 {
1392         struct irq_desc *desc = irq_to_desc(irq);
1393
1394         if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1395             __free_irq(irq, act->dev_id);
1396 }
1397 EXPORT_SYMBOL_GPL(remove_irq);
1398
1399 /**
1400  *      free_irq - free an interrupt allocated with request_irq
1401  *      @irq: Interrupt line to free
1402  *      @dev_id: Device identity to free
1403  *
1404  *      Remove an interrupt handler. The handler is removed and if the
1405  *      interrupt line is no longer in use by any driver it is disabled.
1406  *      On a shared IRQ the caller must ensure the interrupt is disabled
1407  *      on the card it drives before calling this function. The function
1408  *      does not return until any executing interrupts for this IRQ
1409  *      have completed.
1410  *
1411  *      This function must not be called from interrupt context.
1412  */
1413 void free_irq(unsigned int irq, void *dev_id)
1414 {
1415         struct irq_desc *desc = irq_to_desc(irq);
1416
1417         if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1418                 return;
1419
1420 #ifdef CONFIG_SMP
1421         if (WARN_ON(desc->affinity_notify))
1422                 desc->affinity_notify = NULL;
1423 #endif
1424
1425         chip_bus_lock(desc);
1426         kfree(__free_irq(irq, dev_id));
1427         chip_bus_sync_unlock(desc);
1428 }
1429 EXPORT_SYMBOL(free_irq);
1430
1431 /**
1432  *      request_threaded_irq - allocate an interrupt line
1433  *      @irq: Interrupt line to allocate
1434  *      @handler: Function to be called when the IRQ occurs.
1435  *                Primary handler for threaded interrupts
1436  *                If NULL and thread_fn != NULL the default
1437  *                primary handler is installed
1438  *      @thread_fn: Function called from the irq handler thread
1439  *                  If NULL, no irq thread is created
1440  *      @irqflags: Interrupt type flags
1441  *      @devname: An ascii name for the claiming device
1442  *      @dev_id: A cookie passed back to the handler function
1443  *
1444  *      This call allocates interrupt resources and enables the
1445  *      interrupt line and IRQ handling. From the point this
1446  *      call is made your handler function may be invoked. Since
1447  *      your handler function must clear any interrupt the board
1448  *      raises, you must take care both to initialise your hardware
1449  *      and to set up the interrupt handler in the right order.
1450  *
1451  *      If you want to set up a threaded irq handler for your device
1452  *      then you need to supply @handler and @thread_fn. @handler is
1453  *      still called in hard interrupt context and has to check
1454  *      whether the interrupt originates from the device. If yes it
1455  *      needs to disable the interrupt on the device and return
1456  *      IRQ_WAKE_THREAD which will wake up the handler thread and run
1457  *      @thread_fn. This split handler design is necessary to support
1458  *      shared interrupts.
1459  *
1460  *      Dev_id must be globally unique. Normally the address of the
1461  *      device data structure is used as the cookie. Since the handler
1462  *      receives this value it makes sense to use it.
1463  *
1464  *      If your interrupt is shared you must pass a non NULL dev_id
1465  *      as this is required when freeing the interrupt.
1466  *
1467  *      Flags:
1468  *
1469  *      IRQF_SHARED             Interrupt is shared
1470  *      IRQF_TRIGGER_*          Specify active edge(s) or level
1471  *
1472  */
1473 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1474                          irq_handler_t thread_fn, unsigned long irqflags,
1475                          const char *devname, void *dev_id)
1476 {
1477         struct irqaction *action;
1478         struct irq_desc *desc;
1479         int retval;
1480
1481         /*
1482          * Sanity-check: shared interrupts must pass in a real dev-ID,
1483          * otherwise we'll have trouble later trying to figure out
1484          * which interrupt is which (messes up the interrupt freeing
1485          * logic etc).
1486          */
1487         if ((irqflags & IRQF_SHARED) && !dev_id)
1488                 return -EINVAL;
1489
1490         desc = irq_to_desc(irq);
1491         if (!desc)
1492                 return -EINVAL;
1493
1494         if (!irq_settings_can_request(desc) ||
1495             WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1496                 return -EINVAL;
1497
1498         if (!handler) {
1499                 if (!thread_fn)
1500                         return -EINVAL;
1501                 handler = irq_default_primary_handler;
1502         }
1503
1504         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1505         if (!action)
1506                 return -ENOMEM;
1507
1508         action->handler = handler;
1509         action->thread_fn = thread_fn;
1510         action->flags = irqflags;
1511         action->name = devname;
1512         action->dev_id = dev_id;
1513
1514         chip_bus_lock(desc);
1515         retval = __setup_irq(irq, desc, action);
1516         chip_bus_sync_unlock(desc);
1517
1518         if (retval)
1519                 kfree(action);
1520
1521 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1522         if (!retval && (irqflags & IRQF_SHARED)) {
1523                 /*
1524                  * It's a shared IRQ -- the driver ought to be prepared for it
1525                  * to happen immediately, so let's make sure....
1526                  * We disable the irq to make sure that a 'real' IRQ doesn't
1527                  * run in parallel with our fake.
1528                  */
1529                 unsigned long flags;
1530
1531                 disable_irq(irq);
1532                 local_irq_save(flags);
1533
1534                 handler(irq, dev_id);
1535
1536                 local_irq_restore(flags);
1537                 enable_irq(irq);
1538         }
1539 #endif
1540         return retval;
1541 }
1542 EXPORT_SYMBOL(request_threaded_irq);
1543
1544 /**
1545  *      request_any_context_irq - allocate an interrupt line
1546  *      @irq: Interrupt line to allocate
1547  *      @handler: Function to be called when the IRQ occurs.
1548  *                Threaded handler for threaded interrupts.
1549  *      @flags: Interrupt type flags
1550  *      @name: An ascii name for the claiming device
1551  *      @dev_id: A cookie passed back to the handler function
1552  *
1553  *      This call allocates interrupt resources and enables the
1554  *      interrupt line and IRQ handling. It selects either a
1555  *      hardirq or threaded handling method depending on the
1556  *      context.
1557  *
1558  *      On failure, it returns a negative value. On success,
1559  *      it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1560  */
1561 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1562                             unsigned long flags, const char *name, void *dev_id)
1563 {
1564         struct irq_desc *desc = irq_to_desc(irq);
1565         int ret;
1566
1567         if (!desc)
1568                 return -EINVAL;
1569
1570         if (irq_settings_is_nested_thread(desc)) {
1571                 ret = request_threaded_irq(irq, NULL, handler,
1572                                            flags, name, dev_id);
1573                 return !ret ? IRQC_IS_NESTED : ret;
1574         }
1575
1576         ret = request_irq(irq, handler, flags, name, dev_id);
1577         return !ret ? IRQC_IS_HARDIRQ : ret;
1578 }
1579 EXPORT_SYMBOL_GPL(request_any_context_irq);
1580
1581 void enable_percpu_irq(unsigned int irq, unsigned int type)
1582 {
1583         unsigned int cpu = smp_processor_id();
1584         unsigned long flags;
1585         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1586
1587         if (!desc)
1588                 return;
1589
1590         type &= IRQ_TYPE_SENSE_MASK;
1591         if (type != IRQ_TYPE_NONE) {
1592                 int ret;
1593
1594                 ret = __irq_set_trigger(desc, irq, type);
1595
1596                 if (ret) {
1597                         WARN(1, "failed to set type for IRQ%d\n", irq);
1598                         goto out;
1599                 }
1600         }
1601
1602         irq_percpu_enable(desc, cpu);
1603 out:
1604         irq_put_desc_unlock(desc, flags);
1605 }
1606 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1607
1608 void disable_percpu_irq(unsigned int irq)
1609 {
1610         unsigned int cpu = smp_processor_id();
1611         unsigned long flags;
1612         struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1613
1614         if (!desc)
1615                 return;
1616
1617         irq_percpu_disable(desc, cpu);
1618         irq_put_desc_unlock(desc, flags);
1619 }
1620 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1621
1622 /*
1623  * Internal function to unregister a percpu irqaction.
1624  */
1625 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1626 {
1627         struct irq_desc *desc = irq_to_desc(irq);
1628         struct irqaction *action;
1629         unsigned long flags;
1630
1631         WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1632
1633         if (!desc)
1634                 return NULL;
1635
1636         raw_spin_lock_irqsave(&desc->lock, flags);
1637
1638         action = desc->action;
1639         if (!action || action->percpu_dev_id != dev_id) {
1640                 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1641                 goto bad;
1642         }
1643
1644         if (!cpumask_empty(desc->percpu_enabled)) {
1645                 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1646                      irq, cpumask_first(desc->percpu_enabled));
1647                 goto bad;
1648         }
1649
1650         /* Found it - now remove it from the list of entries: */
1651         desc->action = NULL;
1652
1653         raw_spin_unlock_irqrestore(&desc->lock, flags);
1654
1655         unregister_handler_proc(irq, action);
1656
1657         module_put(desc->owner);
1658         return action;
1659
1660 bad:
1661         raw_spin_unlock_irqrestore(&desc->lock, flags);
1662         return NULL;
1663 }
1664
1665 /**
1666  *      remove_percpu_irq - free a per-cpu interrupt
1667  *      @irq: Interrupt line to free
1668  *      @act: irqaction for the interrupt
1669  *
1670  * Used to remove interrupts statically setup by the early boot process.
1671  */
1672 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1673 {
1674         struct irq_desc *desc = irq_to_desc(irq);
1675
1676         if (desc && irq_settings_is_per_cpu_devid(desc))
1677             __free_percpu_irq(irq, act->percpu_dev_id);
1678 }
1679
1680 /**
1681  *      free_percpu_irq - free an interrupt allocated with request_percpu_irq
1682  *      @irq: Interrupt line to free
1683  *      @dev_id: Device identity to free
1684  *
1685  *      Remove a percpu interrupt handler. The handler is removed, but
1686  *      the interrupt line is not disabled. This must be done on each
1687  *      CPU before calling this function. The function does not return
1688  *      until any executing interrupts for this IRQ have completed.
1689  *
1690  *      This function must not be called from interrupt context.
1691  */
1692 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1693 {
1694         struct irq_desc *desc = irq_to_desc(irq);
1695
1696         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1697                 return;
1698
1699         chip_bus_lock(desc);
1700         kfree(__free_percpu_irq(irq, dev_id));
1701         chip_bus_sync_unlock(desc);
1702 }
1703
1704 /**
1705  *      setup_percpu_irq - setup a per-cpu interrupt
1706  *      @irq: Interrupt line to setup
1707  *      @act: irqaction for the interrupt
1708  *
1709  * Used to statically setup per-cpu interrupts in the early boot process.
1710  */
1711 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1712 {
1713         struct irq_desc *desc = irq_to_desc(irq);
1714         int retval;
1715
1716         if (!desc || !irq_settings_is_per_cpu_devid(desc))
1717                 return -EINVAL;
1718         chip_bus_lock(desc);
1719         retval = __setup_irq(irq, desc, act);
1720         chip_bus_sync_unlock(desc);
1721
1722         return retval;
1723 }
1724
1725 /**
1726  *      request_percpu_irq - allocate a percpu interrupt line
1727  *      @irq: Interrupt line to allocate
1728  *      @handler: Function to be called when the IRQ occurs.
1729  *      @devname: An ascii name for the claiming device
1730  *      @dev_id: A percpu cookie passed back to the handler function
1731  *
1732  *      This call allocates interrupt resources, but doesn't
1733  *      automatically enable the interrupt. It has to be done on each
1734  *      CPU using enable_percpu_irq().
1735  *
1736  *      Dev_id must be globally unique. It is a per-cpu variable, and
1737  *      the handler gets called with the interrupted CPU's instance of
1738  *      that variable.
1739  */
1740 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1741                        const char *devname, void __percpu *dev_id)
1742 {
1743         struct irqaction *action;
1744         struct irq_desc *desc;
1745         int retval;
1746
1747         if (!dev_id)
1748                 return -EINVAL;
1749
1750         desc = irq_to_desc(irq);
1751         if (!desc || !irq_settings_can_request(desc) ||
1752             !irq_settings_is_per_cpu_devid(desc))
1753                 return -EINVAL;
1754
1755         action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1756         if (!action)
1757                 return -ENOMEM;
1758
1759         action->handler = handler;
1760         action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1761         action->name = devname;
1762         action->percpu_dev_id = dev_id;
1763
1764         chip_bus_lock(desc);
1765         retval = __setup_irq(irq, desc, action);
1766         chip_bus_sync_unlock(desc);
1767
1768         if (retval)
1769                 kfree(action);
1770
1771         return retval;
1772 }