include/linux/interrupt.h

   1 /* interrupt.h */
   2 #ifndef _LINUX_INTERRUPT_H
   3 #define _LINUX_INTERRUPT_H
   4
   5 #include <linux/kernel.h>
   6 #include <linux/linkage.h>
   7 #include <linux/bitops.h>
   8 #include <linux/preempt.h>
   9 #include <linux/cpumask.h>
  10 #include <linux/irqreturn.h>
  11 #include <linux/irqnr.h>
  12 #include <linux/hardirq.h>
  13 #include <linux/irqflags.h>
  14 #include <linux/hrtimer.h>
  15 #include <linux/kref.h>
  16 #include <linux/workqueue.h>
  17
  18 #include <linux/atomic.h>
  19 #include <asm/ptrace.h>
  20 #include <asm/irq.h>
  21
  22 /*
  23  * These correspond to the IORESOURCE_IRQ_* defines in
  24  * linux/ioport.h to select the interrupt line behaviour.  When
  25  * requesting an interrupt without specifying a IRQF_TRIGGER, the
  26  * setting should be assumed to be "as already configured", which
  27  * may be as per machine or firmware initialisation.
  28  */
  29 #define IRQF_TRIGGER_NONE       0x00000000
  30 #define IRQF_TRIGGER_RISING     0x00000001
  31 #define IRQF_TRIGGER_FALLING    0x00000002
  32 #define IRQF_TRIGGER_HIGH       0x00000004
  33 #define IRQF_TRIGGER_LOW        0x00000008
  34 #define IRQF_TRIGGER_MASK       (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
  35                                  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
  36 #define IRQF_TRIGGER_PROBE      0x00000010
  37
  38 /*
  39  * These flags used only by the kernel as part of the
  40  * irq handling routines.
  41  *
  42  * IRQF_DISABLED - keep irqs disabled when calling the action handler.
  43  *                 DEPRECATED. This flag is a NOOP and scheduled to be removed
  44  * IRQF_SHARED - allow sharing the irq among several devices
  45  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
  46  * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
  47  * IRQF_PERCPU - Interrupt is per cpu
  48  * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
  49  * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
  50  *                registered first in an shared interrupt is considered for
  51  *                performance reasons)
  52  * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
  53  *                Used by threaded interrupts which need to keep the
  54  *                irq line disabled until the threaded handler has been run.
  55  * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend.  Does not guarantee
  56  *                   that this interrupt will wake the system from a suspended
  57  *                   state.  See Documentation/power/suspend-and-interrupts.txt
  58  * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
  59  * IRQF_NO_THREAD - Interrupt cannot be threaded
  60  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
  61  *                resume time.
  62  * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this
  63  *                interrupt handler after suspending interrupts. For system
  64  *                wakeup devices users need to implement wakeup detection in
  65  *                their interrupt handlers.
  66  */
  67 #define IRQF_DISABLED           0x00000020
  68 #define IRQF_SHARED             0x00000080
  69 #define IRQF_PROBE_SHARED       0x00000100
  70 #define __IRQF_TIMER            0x00000200
  71 #define IRQF_PERCPU             0x00000400
  72 #define IRQF_NOBALANCING        0x00000800
  73 #define IRQF_IRQPOLL            0x00001000
  74 #define IRQF_ONESHOT            0x00002000
  75 #define IRQF_NO_SUSPEND         0x00004000
  76 #define IRQF_FORCE_RESUME       0x00008000
  77 #define IRQF_NO_THREAD          0x00010000
  78 #define IRQF_EARLY_RESUME       0x00020000
  79 #define IRQF_COND_SUSPEND       0x00040000
  80
  81 #define IRQF_TIMER              (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
  82
  83 /*
  84  * These values can be returned by request_any_context_irq() and
  85  * describe the context the interrupt will be run in.
  86  *
  87  * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
  88  * IRQC_IS_NESTED - interrupt runs in a nested threaded context
  89  */
  90 enum {
  91         IRQC_IS_HARDIRQ = 0,
  92         IRQC_IS_NESTED,
  93 };
  94
  95 typedef irqreturn_t (*irq_handler_t)(int, void *);
  96
  97 /**
  98  * struct irqaction - per interrupt action descriptor
  99  * @handler:    interrupt handler function
 100  * @name:       name of the device
 101  * @dev_id:     cookie to identify the device
 102  * @percpu_dev_id:      cookie to identify the device
 103  * @next:       pointer to the next irqaction for shared interrupts
 104  * @irq:        interrupt number
 105  * @flags:      flags (see IRQF_* above)
 106  * @thread_fn:  interrupt handler function for threaded interrupts
 107  * @thread:     thread pointer for threaded interrupts
 108  * @thread_flags:       flags related to @thread
 109  * @thread_mask:        bitmask for keeping track of @thread activity
 110  * @dir:        pointer to the proc/irq/NN/name entry
 111  */
 112 struct irqaction {
 113         irq_handler_t           handler;
 114         void                    *dev_id;
 115         void __percpu           *percpu_dev_id;
 116         struct irqaction        *next;
 117         irq_handler_t           thread_fn;
 118         struct task_struct      *thread;
 119         unsigned int            irq;
 120         unsigned int            flags;
 121         unsigned long           thread_flags;
 122         unsigned long           thread_mask;
 123         const char              *name;
 124         struct proc_dir_entry   *dir;
 125 } ____cacheline_internodealigned_in_smp;
 126
 127 extern irqreturn_t no_action(int cpl, void *dev_id);
 128
 129 extern int __must_check
 130 request_threaded_irq(unsigned int irq, irq_handler_t handler,
 131                      irq_handler_t thread_fn,
 132                      unsigned long flags, const char *name, void *dev);
 133
 134 static inline int __must_check
 135 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
 136             const char *name, void *dev)
 137 {
 138         return request_threaded_irq(irq, handler, NULL, flags, name, dev);
 139 }
 140
 141 extern int __must_check
 142 request_any_context_irq(unsigned int irq, irq_handler_t handler,
 143                         unsigned long flags, const char *name, void *dev_id);
 144
 145 extern int __must_check
 146 request_percpu_irq(unsigned int irq, irq_handler_t handler,
 147                    const char *devname, void __percpu *percpu_dev_id);
 148
 149 extern void free_irq(unsigned int, void *);
 150 extern void free_percpu_irq(unsigned int, void __percpu *);
 151
 152 struct device;
 153
 154 extern int __must_check
 155 devm_request_threaded_irq(struct device *dev, unsigned int irq,
 156                           irq_handler_t handler, irq_handler_t thread_fn,
 157                           unsigned long irqflags, const char *devname,
 158                           void *dev_id);
 159
 160 static inline int __must_check
 161 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
 162                  unsigned long irqflags, const char *devname, void *dev_id)
 163 {
 164         return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
 165                                          devname, dev_id);
 166 }
 167
 168 extern int __must_check
 169 devm_request_any_context_irq(struct device *dev, unsigned int irq,
 170                  irq_handler_t handler, unsigned long irqflags,
 171                  const char *devname, void *dev_id);
 172
 173 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
 174
 175 /*
 176  * On lockdep we dont want to enable hardirqs in hardirq
 177  * context. Use local_irq_enable_in_hardirq() to annotate
 178  * kernel code that has to do this nevertheless (pretty much
 179  * the only valid case is for old/broken hardware that is
 180  * insanely slow).
 181  *
 182  * NOTE: in theory this might break fragile code that relies
 183  * on hardirq delivery - in practice we dont seem to have such
 184  * places left. So the only effect should be slightly increased
 185  * irqs-off latencies.
 186  */
 187 #ifdef CONFIG_LOCKDEP
 188 # define local_irq_enable_in_hardirq()  do { } while (0)
 189 #else
 190 # define local_irq_enable_in_hardirq()  local_irq_enable()
 191 #endif
 192
 193 extern void disable_irq_nosync(unsigned int irq);
 194 extern void disable_irq(unsigned int irq);
 195 extern void disable_percpu_irq(unsigned int irq);
 196 extern void enable_irq(unsigned int irq);
 197 extern void enable_percpu_irq(unsigned int irq, unsigned int type);
 198 extern void irq_wake_thread(unsigned int irq, void *dev_id);
 199
 200 /* The following three functions are for the core kernel use only. */
 201 extern void suspend_device_irqs(void);
 202 extern void resume_device_irqs(void);
 203
 204 /**
 205  * struct irq_affinity_notify - context for notification of IRQ affinity changes
 206  * @irq:                Interrupt to which notification applies
 207  * @kref:               Reference count, for internal use
 208  * @work:               Work item, for internal use
 209  * @notify:             Function to be called on change.  This will be
 210  *                      called in process context.
 211  * @release:            Function to be called on release.  This will be
 212  *                      called in process context.  Once registered, the
 213  *                      structure must only be freed when this function is
 214  *                      called or later.
 215  */
 216 struct irq_affinity_notify {
 217         unsigned int irq;
 218         struct kref kref;
 219         struct work_struct work;
 220         void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
 221         void (*release)(struct kref *ref);
 222 };
 223
 224 #if defined(CONFIG_SMP)
 225
 226 extern cpumask_var_t irq_default_affinity;
 227
 228 /* Internal implementation. Use the helpers below */
 229 extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask,
 230                               bool force);
 231
 232 /**
 233  * irq_set_affinity - Set the irq affinity of a given irq
 234  * @irq:        Interrupt to set affinity
 235  * @cpumask:    cpumask
 236  *
 237  * Fails if cpumask does not contain an online CPU
 238  */
 239 static inline int
 240 irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
 241 {
 242         return __irq_set_affinity(irq, cpumask, false);
 243 }
 244
 245 /**
 246  * irq_force_affinity - Force the irq affinity of a given irq
 247  * @irq:        Interrupt to set affinity
 248  * @cpumask:    cpumask
 249  *
 250  * Same as irq_set_affinity, but without checking the mask against
 251  * online cpus.
 252  *
 253  * Solely for low level cpu hotplug code, where we need to make per
 254  * cpu interrupts affine before the cpu becomes online.
 255  */
 256 static inline int
 257 irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
 258 {
 259         return __irq_set_affinity(irq, cpumask, true);
 260 }
 261
 262 extern int irq_can_set_affinity(unsigned int irq);
 263 extern int irq_select_affinity(unsigned int irq);
 264
 265 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
 266
 267 extern int
 268 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 269
 270 #else /* CONFIG_SMP */
 271
 272 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
 273 {
 274         return -EINVAL;
 275 }
 276
 277 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
 278 {
 279         return 0;
 280 }
 281
 282 static inline int irq_can_set_affinity(unsigned int irq)
 283 {
 284         return 0;
 285 }
 286
 287 static inline int irq_select_affinity(unsigned int irq)  { return 0; }
 288
 289 static inline int irq_set_affinity_hint(unsigned int irq,
 290                                         const struct cpumask *m)
 291 {
 292         return -EINVAL;
 293 }
 294
 295 static inline int
 296 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 297 {
 298         return 0;
 299 }
 300 #endif /* CONFIG_SMP */
 301
 302 /*
 303  * Special lockdep variants of irq disabling/enabling.
 304  * These should be used for locking constructs that
 305  * know that a particular irq context which is disabled,
 306  * and which is the only irq-context user of a lock,
 307  * that it's safe to take the lock in the irq-disabled
 308  * section without disabling hardirqs.
 309  *
 310  * On !CONFIG_LOCKDEP they are equivalent to the normal
 311  * irq disable/enable methods.
 312  */
 313 static inline void disable_irq_nosync_lockdep(unsigned int irq)
 314 {
 315         disable_irq_nosync(irq);
 316 #ifdef CONFIG_LOCKDEP
 317         local_irq_disable();
 318 #endif
 319 }
 320
 321 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
 322 {
 323         disable_irq_nosync(irq);
 324 #ifdef CONFIG_LOCKDEP
 325         local_irq_save(*flags);
 326 #endif
 327 }
 328
 329 static inline void disable_irq_lockdep(unsigned int irq)
 330 {
 331         disable_irq(irq);
 332 #ifdef CONFIG_LOCKDEP
 333         local_irq_disable();
 334 #endif
 335 }
 336
 337 static inline void enable_irq_lockdep(unsigned int irq)
 338 {
 339 #ifdef CONFIG_LOCKDEP
 340         local_irq_enable();
 341 #endif
 342         enable_irq(irq);
 343 }
 344
 345 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
 346 {
 347 #ifdef CONFIG_LOCKDEP
 348         local_irq_restore(*flags);
 349 #endif
 350         enable_irq(irq);
 351 }
 352
 353 /* IRQ wakeup (PM) control: */
 354 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
 355
 356 static inline int enable_irq_wake(unsigned int irq)
 357 {
 358         return irq_set_irq_wake(irq, 1);
 359 }
 360
 361 static inline int disable_irq_wake(unsigned int irq)
 362 {
 363         return irq_set_irq_wake(irq, 0);
 364 }
 365
 366
 367 #ifdef CONFIG_IRQ_FORCED_THREADING
 368 extern bool force_irqthreads;
 369 #else
 370 #define force_irqthreads        (0)
 371 #endif
 372
 373 #ifndef __ARCH_SET_SOFTIRQ_PENDING
 374 #define set_softirq_pending(x) (local_softirq_pending() = (x))
 375 #define or_softirq_pending(x)  (local_softirq_pending() |= (x))
 376 #endif
 377
 378 /* Some architectures might implement lazy enabling/disabling of
 379  * interrupts. In some cases, such as stop_machine, we might want
 380  * to ensure that after a local_irq_disable(), interrupts have
 381  * really been disabled in hardware. Such architectures need to
 382  * implement the following hook.
 383  */
 384 #ifndef hard_irq_disable
 385 #define hard_irq_disable()      do { } while(0)
 386 #endif
 387
 388 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
 389    frequency threaded job scheduling. For almost all the purposes
 390    tasklets are more than enough. F.e. all serial device BHs et
 391    al. should be converted to tasklets, not to softirqs.
 392  */
 393
 394 enum
 395 {
 396         HI_SOFTIRQ=0,
 397         TIMER_SOFTIRQ,
 398         NET_TX_SOFTIRQ,
 399         NET_RX_SOFTIRQ,
 400         BLOCK_SOFTIRQ,
 401         BLOCK_IOPOLL_SOFTIRQ,
 402         TASKLET_SOFTIRQ,
 403         SCHED_SOFTIRQ,
 404         HRTIMER_SOFTIRQ,
 405         RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
 406
 407         NR_SOFTIRQS
 408 };
 409
 410 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
 411
 412 /* map softirq index to softirq name. update 'softirq_to_name' in
 413  * kernel/softirq.c when adding a new softirq.
 414  */
 415 extern const char * const softirq_to_name[NR_SOFTIRQS];
 416
 417 /* softirq mask and active fields moved to irq_cpustat_t in
 418  * asm/hardirq.h to get better cache usage.  KAO
 419  */
 420
 421 struct softirq_action
 422 {
 423         void    (*action)(struct softirq_action *);
 424 };
 425
 426 asmlinkage void do_softirq(void);
 427 asmlinkage void __do_softirq(void);
 428
 429 #ifdef __ARCH_HAS_DO_SOFTIRQ
 430 void do_softirq_own_stack(void);
 431 #else
 432 static inline void do_softirq_own_stack(void)
 433 {
 434         __do_softirq();
 435 }
 436 #endif
 437
 438 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 439 extern void softirq_init(void);
 440 extern void __raise_softirq_irqoff(unsigned int nr);
 441
 442 extern void raise_softirq_irqoff(unsigned int nr);
 443 extern void raise_softirq(unsigned int nr);
 444
 445 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
 446
 447 static inline struct task_struct *this_cpu_ksoftirqd(void)
 448 {
 449         return this_cpu_read(ksoftirqd);
 450 }
 451
 452 /* Tasklets --- multithreaded analogue of BHs.
 453
 454    Main feature differing them of generic softirqs: tasklet
 455    is running only on one CPU simultaneously.
 456
 457    Main feature differing them of BHs: different tasklets
 458    may be run simultaneously on different CPUs.
 459
 460    Properties:
 461    * If tasklet_schedule() is called, then tasklet is guaranteed
 462      to be executed on some cpu at least once after this.
 463    * If the tasklet is already scheduled, but its execution is still not
 464      started, it will be executed only once.
 465    * If this tasklet is already running on another CPU (or schedule is called
 466      from tasklet itself), it is rescheduled for later.
 467    * Tasklet is strictly serialized wrt itself, but not
 468      wrt another tasklets. If client needs some intertask synchronization,
 469      he makes it with spinlocks.
 470  */
 471
 472 struct tasklet_struct
 473 {
 474         struct tasklet_struct *next;
 475         unsigned long state;
 476         atomic_t count;
 477         void (*func)(unsigned long);
 478         unsigned long data;
 479 };
 480
 481 #define DECLARE_TASKLET(name, func, data) \
 482 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
 483
 484 #define DECLARE_TASKLET_DISABLED(name, func, data) \
 485 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 486
 487
 488 enum
 489 {
 490         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
 491         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
 492 };
 493
 494 #ifdef CONFIG_SMP
 495 static inline int tasklet_trylock(struct tasklet_struct *t)
 496 {
 497         return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 498 }
 499
 500 static inline void tasklet_unlock(struct tasklet_struct *t)
 501 {
 502         smp_mb__before_atomic();
 503         clear_bit(TASKLET_STATE_RUN, &(t)->state);
 504 }
 505
 506 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 507 {
 508         while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
 509 }
 510 #else
 511 #define tasklet_trylock(t) 1
 512 #define tasklet_unlock_wait(t) do { } while (0)
 513 #define tasklet_unlock(t) do { } while (0)
 514 #endif
 515
 516 extern void __tasklet_schedule(struct tasklet_struct *t);
 517
 518 static inline void tasklet_schedule(struct tasklet_struct *t)
 519 {
 520         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 521                 __tasklet_schedule(t);
 522 }
 523
 524 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
 525
 526 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 527 {
 528         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 529                 __tasklet_hi_schedule(t);
 530 }
 531
 532 extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
 533
 534 /*
 535  * This version avoids touching any other tasklets. Needed for kmemcheck
 536  * in order not to take any page faults while enqueueing this tasklet;
 537  * consider VERY carefully whether you really need this or
 538  * tasklet_hi_schedule()...
 539  */
 540 static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
 541 {
 542         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 543                 __tasklet_hi_schedule_first(t);
 544 }
 545
 546
 547 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 548 {
 549         atomic_inc(&t->count);
 550         smp_mb__after_atomic();
 551 }
 552
 553 static inline void tasklet_disable(struct tasklet_struct *t)
 554 {
 555         tasklet_disable_nosync(t);
 556         tasklet_unlock_wait(t);
 557         smp_mb();
 558 }
 559
 560 static inline void tasklet_enable(struct tasklet_struct *t)
 561 {
 562         smp_mb__before_atomic();
 563         atomic_dec(&t->count);
 564 }
 565
 566 extern void tasklet_kill(struct tasklet_struct *t);
 567 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
 568 extern void tasklet_init(struct tasklet_struct *t,
 569                          void (*func)(unsigned long), unsigned long data);
 570
 571 struct tasklet_hrtimer {
 572         struct hrtimer          timer;
 573         struct tasklet_struct   tasklet;
 574         enum hrtimer_restart    (*function)(struct hrtimer *);
 575 };
 576
 577 extern void
 578 tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
 579                      enum hrtimer_restart (*function)(struct hrtimer *),
 580                      clockid_t which_clock, enum hrtimer_mode mode);
 581
 582 static inline
 583 int tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
 584                           const enum hrtimer_mode mode)
 585 {
 586         return hrtimer_start(&ttimer->timer, time, mode);
 587 }
 588
 589 static inline
 590 void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
 591 {
 592         hrtimer_cancel(&ttimer->timer);
 593         tasklet_kill(&ttimer->tasklet);
 594 }
 595
 596 /*
 597  * Autoprobing for irqs:
 598  *
 599  * probe_irq_on() and probe_irq_off() provide robust primitives
 600  * for accurate IRQ probing during kernel initialization.  They are
 601  * reasonably simple to use, are not "fooled" by spurious interrupts,
 602  * and, unlike other attempts at IRQ probing, they do not get hung on
 603  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
 604  *
 605  * For reasonably foolproof probing, use them as follows:
 606  *
 607  * 1. clear and/or mask the device's internal interrupt.
 608  * 2. sti();
 609  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
 610  * 4. enable the device and cause it to trigger an interrupt.
 611  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
 612  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
 613  * 7. service the device to clear its pending interrupt.
 614  * 8. loop again if paranoia is required.
 615  *
 616  * probe_irq_on() returns a mask of allocated irq's.
 617  *
 618  * probe_irq_off() takes the mask as a parameter,
 619  * and returns the irq number which occurred,
 620  * or zero if none occurred, or a negative irq number
 621  * if more than one irq occurred.
 622  */
 623
 624 #if !defined(CONFIG_GENERIC_IRQ_PROBE)
 625 static inline unsigned long probe_irq_on(void)
 626 {
 627         return 0;
 628 }
 629 static inline int probe_irq_off(unsigned long val)
 630 {
 631         return 0;
 632 }
 633 static inline unsigned int probe_irq_mask(unsigned long val)
 634 {
 635         return 0;
 636 }
 637 #else
 638 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
 639 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
 640 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
 641 #endif
 642
 643 #ifdef CONFIG_PROC_FS
 644 /* Initialize /proc/irq/ */
 645 extern void init_irq_proc(void);
 646 #else
 647 static inline void init_irq_proc(void)
 648 {
 649 }
 650 #endif
 651
 652 struct seq_file;
 653 int show_interrupts(struct seq_file *p, void *v);
 654 int arch_show_interrupts(struct seq_file *p, int prec);
 655
 656 extern int early_irq_init(void);
 657 extern int arch_probe_nr_irqs(void);
 658 extern int arch_early_irq_init(void);
 659
 660 #endif