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
  56  * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
  57  * IRQF_NO_THREAD - Interrupt cannot be threaded
  58  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
  59  *                resume time.
  60  */
  61 #define IRQF_DISABLED           0x00000020
  62 #define IRQF_SHARED             0x00000080
  63 #define IRQF_PROBE_SHARED       0x00000100
  64 #define __IRQF_TIMER            0x00000200
  65 #define IRQF_PERCPU             0x00000400
  66 #define IRQF_NOBALANCING        0x00000800
  67 #define IRQF_IRQPOLL            0x00001000
  68 #define IRQF_ONESHOT            0x00002000
  69 #define IRQF_NO_SUSPEND         0x00004000
  70 #define IRQF_FORCE_RESUME       0x00008000
  71 #define IRQF_NO_THREAD          0x00010000
  72 #define IRQF_EARLY_RESUME       0x00020000
  73
  74 #define IRQF_TIMER              (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
  75
  76 /*
  77  * These values can be returned by request_any_context_irq() and
  78  * describe the context the interrupt will be run in.
  79  *
  80  * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
  81  * IRQC_IS_NESTED - interrupt runs in a nested threaded context
  82  */
  83 enum {
  84         IRQC_IS_HARDIRQ = 0,
  85         IRQC_IS_NESTED,
  86 };
  87
  88 typedef irqreturn_t (*irq_handler_t)(int, void *);
  89
  90 /**
  91  * struct irqaction - per interrupt action descriptor
  92  * @handler:    interrupt handler function
  93  * @name:       name of the device
  94  * @dev_id:     cookie to identify the device
  95  * @percpu_dev_id:      cookie to identify the device
  96  * @next:       pointer to the next irqaction for shared interrupts
  97  * @irq:        interrupt number
  98  * @flags:      flags (see IRQF_* above)
  99  * @thread_fn:  interrupt handler function for threaded interrupts
 100  * @thread:     thread pointer for threaded interrupts
 101  * @thread_flags:       flags related to @thread
 102  * @thread_mask:        bitmask for keeping track of @thread activity
 103  * @dir:        pointer to the proc/irq/NN/name entry
 104  */
 105 struct irqaction {
 106         irq_handler_t           handler;
 107         void                    *dev_id;
 108         void __percpu           *percpu_dev_id;
 109         struct irqaction        *next;
 110         irq_handler_t           thread_fn;
 111         struct task_struct      *thread;
 112         unsigned int            irq;
 113         unsigned int            flags;
 114         unsigned long           thread_flags;
 115         unsigned long           thread_mask;
 116         const char              *name;
 117         struct proc_dir_entry   *dir;
 118 } ____cacheline_internodealigned_in_smp;
 119
 120 extern irqreturn_t no_action(int cpl, void *dev_id);
 121
 122 extern int __must_check
 123 request_threaded_irq(unsigned int irq, irq_handler_t handler,
 124                      irq_handler_t thread_fn,
 125                      unsigned long flags, const char *name, void *dev);
 126
 127 static inline int __must_check
 128 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
 129             const char *name, void *dev)
 130 {
 131         return request_threaded_irq(irq, handler, NULL, flags, name, dev);
 132 }
 133
 134 extern int __must_check
 135 request_any_context_irq(unsigned int irq, irq_handler_t handler,
 136                         unsigned long flags, const char *name, void *dev_id);
 137
 138 extern int __must_check
 139 request_percpu_irq(unsigned int irq, irq_handler_t handler,
 140                    const char *devname, void __percpu *percpu_dev_id);
 141
 142 extern void free_irq(unsigned int, void *);
 143 extern void free_percpu_irq(unsigned int, void __percpu *);
 144
 145 struct device;
 146
 147 extern int __must_check
 148 devm_request_threaded_irq(struct device *dev, unsigned int irq,
 149                           irq_handler_t handler, irq_handler_t thread_fn,
 150                           unsigned long irqflags, const char *devname,
 151                           void *dev_id);
 152
 153 static inline int __must_check
 154 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
 155                  unsigned long irqflags, const char *devname, void *dev_id)
 156 {
 157         return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
 158                                          devname, dev_id);
 159 }
 160
 161 extern int __must_check
 162 devm_request_any_context_irq(struct device *dev, unsigned int irq,
 163                  irq_handler_t handler, unsigned long irqflags,
 164                  const char *devname, void *dev_id);
 165
 166 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
 167
 168 /*
 169  * On lockdep we dont want to enable hardirqs in hardirq
 170  * context. Use local_irq_enable_in_hardirq() to annotate
 171  * kernel code that has to do this nevertheless (pretty much
 172  * the only valid case is for old/broken hardware that is
 173  * insanely slow).
 174  *
 175  * NOTE: in theory this might break fragile code that relies
 176  * on hardirq delivery - in practice we dont seem to have such
 177  * places left. So the only effect should be slightly increased
 178  * irqs-off latencies.
 179  */
 180 #ifdef CONFIG_LOCKDEP
 181 # define local_irq_enable_in_hardirq()  do { } while (0)
 182 #else
 183 # define local_irq_enable_in_hardirq()  local_irq_enable()
 184 #endif
 185
 186 extern void disable_irq_nosync(unsigned int irq);
 187 extern void disable_irq(unsigned int irq);
 188 extern void disable_percpu_irq(unsigned int irq);
 189 extern void enable_irq(unsigned int irq);
 190 extern void enable_percpu_irq(unsigned int irq, unsigned int type);
 191 extern void irq_wake_thread(unsigned int irq, void *dev_id);
 192
 193 /* The following three functions are for the core kernel use only. */
 194 extern void suspend_device_irqs(void);
 195 extern void resume_device_irqs(void);
 196 #ifdef CONFIG_PM_SLEEP
 197 extern int check_wakeup_irqs(void);
 198 #else
 199 static inline int check_wakeup_irqs(void) { return 0; }
 200 #endif
 201
 202 /**
 203  * struct irq_affinity_notify - context for notification of IRQ affinity changes
 204  * @irq:                Interrupt to which notification applies
 205  * @kref:               Reference count, for internal use
 206  * @work:               Work item, for internal use
 207  * @notify:             Function to be called on change.  This will be
 208  *                      called in process context.
 209  * @release:            Function to be called on release.  This will be
 210  *                      called in process context.  Once registered, the
 211  *                      structure must only be freed when this function is
 212  *                      called or later.
 213  */
 214 struct irq_affinity_notify {
 215         unsigned int irq;
 216         struct kref kref;
 217         struct work_struct work;
 218         void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
 219         void (*release)(struct kref *ref);
 220 };
 221
 222 #if defined(CONFIG_SMP)
 223
 224 extern cpumask_var_t irq_default_affinity;
 225
 226 /* Internal implementation. Use the helpers below */
 227 extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask,
 228                               bool force);
 229
 230 /**
 231  * irq_set_affinity - Set the irq affinity of a given irq
 232  * @irq:        Interrupt to set affinity
 233  * @cpumask:    cpumask
 234  *
 235  * Fails if cpumask does not contain an online CPU
 236  */
 237 static inline int
 238 irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
 239 {
 240         return __irq_set_affinity(irq, cpumask, false);
 241 }
 242
 243 /**
 244  * irq_force_affinity - Force the irq affinity of a given irq
 245  * @irq:        Interrupt to set affinity
 246  * @cpumask:    cpumask
 247  *
 248  * Same as irq_set_affinity, but without checking the mask against
 249  * online cpus.
 250  *
 251  * Solely for low level cpu hotplug code, where we need to make per
 252  * cpu interrupts affine before the cpu becomes online.
 253  */
 254 static inline int
 255 irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
 256 {
 257         return __irq_set_affinity(irq, cpumask, true);
 258 }
 259
 260 extern int irq_can_set_affinity(unsigned int irq);
 261 extern int irq_select_affinity(unsigned int irq);
 262
 263 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
 264
 265 extern int
 266 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
 267
 268 #else /* CONFIG_SMP */
 269
 270 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
 271 {
 272         return -EINVAL;
 273 }
 274
 275 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
 276 {
 277         return 0;
 278 }
 279
 280 static inline int irq_can_set_affinity(unsigned int irq)
 281 {
 282         return 0;
 283 }
 284
 285 static inline int irq_select_affinity(unsigned int irq)  { return 0; }
 286
 287 static inline int irq_set_affinity_hint(unsigned int irq,
 288                                         const struct cpumask *m)
 289 {
 290         return -EINVAL;
 291 }
 292
 293 static inline int
 294 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
 295 {
 296         return 0;
 297 }
 298 #endif /* CONFIG_SMP */
 299
 300 /*
 301  * Special lockdep variants of irq disabling/enabling.
 302  * These should be used for locking constructs that
 303  * know that a particular irq context which is disabled,
 304  * and which is the only irq-context user of a lock,
 305  * that it's safe to take the lock in the irq-disabled
 306  * section without disabling hardirqs.
 307  *
 308  * On !CONFIG_LOCKDEP they are equivalent to the normal
 309  * irq disable/enable methods.
 310  */
 311 static inline void disable_irq_nosync_lockdep(unsigned int irq)
 312 {
 313         disable_irq_nosync(irq);
 314 #ifdef CONFIG_LOCKDEP
 315         local_irq_disable();
 316 #endif
 317 }
 318
 319 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
 320 {
 321         disable_irq_nosync(irq);
 322 #ifdef CONFIG_LOCKDEP
 323         local_irq_save(*flags);
 324 #endif
 325 }
 326
 327 static inline void disable_irq_lockdep(unsigned int irq)
 328 {
 329         disable_irq(irq);
 330 #ifdef CONFIG_LOCKDEP
 331         local_irq_disable();
 332 #endif
 333 }
 334
 335 static inline void enable_irq_lockdep(unsigned int irq)
 336 {
 337 #ifdef CONFIG_LOCKDEP
 338         local_irq_enable();
 339 #endif
 340         enable_irq(irq);
 341 }
 342
 343 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
 344 {
 345 #ifdef CONFIG_LOCKDEP
 346         local_irq_restore(*flags);
 347 #endif
 348         enable_irq(irq);
 349 }
 350
 351 /* IRQ wakeup (PM) control: */
 352 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
 353
 354 static inline int enable_irq_wake(unsigned int irq)
 355 {
 356         return irq_set_irq_wake(irq, 1);
 357 }
 358
 359 static inline int disable_irq_wake(unsigned int irq)
 360 {
 361         return irq_set_irq_wake(irq, 0);
 362 }
 363
 364
 365 #ifdef CONFIG_IRQ_FORCED_THREADING
 366 extern bool force_irqthreads;
 367 #else
 368 #define force_irqthreads        (0)
 369 #endif
 370
 371 #ifndef __ARCH_SET_SOFTIRQ_PENDING
 372 #define set_softirq_pending(x) (local_softirq_pending() = (x))
 373 #define or_softirq_pending(x)  (local_softirq_pending() |= (x))
 374 #endif
 375
 376 /* Some architectures might implement lazy enabling/disabling of
 377  * interrupts. In some cases, such as stop_machine, we might want
 378  * to ensure that after a local_irq_disable(), interrupts have
 379  * really been disabled in hardware. Such architectures need to
 380  * implement the following hook.
 381  */
 382 #ifndef hard_irq_disable
 383 #define hard_irq_disable()      do { } while(0)
 384 #endif
 385
 386 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
 387    frequency threaded job scheduling. For almost all the purposes
 388    tasklets are more than enough. F.e. all serial device BHs et
 389    al. should be converted to tasklets, not to softirqs.
 390  */
 391
 392 enum
 393 {
 394         HI_SOFTIRQ=0,
 395         TIMER_SOFTIRQ,
 396         NET_TX_SOFTIRQ,
 397         NET_RX_SOFTIRQ,
 398         BLOCK_SOFTIRQ,
 399         BLOCK_IOPOLL_SOFTIRQ,
 400         TASKLET_SOFTIRQ,
 401         SCHED_SOFTIRQ,
 402         HRTIMER_SOFTIRQ,
 403         RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
 404
 405         NR_SOFTIRQS
 406 };
 407
 408 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
 409
 410 /* map softirq index to softirq name. update 'softirq_to_name' in
 411  * kernel/softirq.c when adding a new softirq.
 412  */
 413 extern const char * const softirq_to_name[NR_SOFTIRQS];
 414
 415 /* softirq mask and active fields moved to irq_cpustat_t in
 416  * asm/hardirq.h to get better cache usage.  KAO
 417  */
 418
 419 struct softirq_action
 420 {
 421         void    (*action)(struct softirq_action *);
 422 };
 423
 424 asmlinkage void do_softirq(void);
 425 asmlinkage void __do_softirq(void);
 426
 427 #ifdef __ARCH_HAS_DO_SOFTIRQ
 428 void do_softirq_own_stack(void);
 429 #else
 430 static inline void do_softirq_own_stack(void)
 431 {
 432         __do_softirq();
 433 }
 434 #endif
 435
 436 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
 437 extern void softirq_init(void);
 438 extern void __raise_softirq_irqoff(unsigned int nr);
 439
 440 extern void raise_softirq_irqoff(unsigned int nr);
 441 extern void raise_softirq(unsigned int nr);
 442
 443 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
 444
 445 static inline struct task_struct *this_cpu_ksoftirqd(void)
 446 {
 447         return this_cpu_read(ksoftirqd);
 448 }
 449
 450 /* Tasklets --- multithreaded analogue of BHs.
 451
 452    Main feature differing them of generic softirqs: tasklet
 453    is running only on one CPU simultaneously.
 454
 455    Main feature differing them of BHs: different tasklets
 456    may be run simultaneously on different CPUs.
 457
 458    Properties:
 459    * If tasklet_schedule() is called, then tasklet is guaranteed
 460      to be executed on some cpu at least once after this.
 461    * If the tasklet is already scheduled, but its execution is still not
 462      started, it will be executed only once.
 463    * If this tasklet is already running on another CPU (or schedule is called
 464      from tasklet itself), it is rescheduled for later.
 465    * Tasklet is strictly serialized wrt itself, but not
 466      wrt another tasklets. If client needs some intertask synchronization,
 467      he makes it with spinlocks.
 468  */
 469
 470 struct tasklet_struct
 471 {
 472         struct tasklet_struct *next;
 473         unsigned long state;
 474         atomic_t count;
 475         void (*func)(unsigned long);
 476         unsigned long data;
 477 };
 478
 479 #define DECLARE_TASKLET(name, func, data) \
 480 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
 481
 482 #define DECLARE_TASKLET_DISABLED(name, func, data) \
 483 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 484
 485
 486 enum
 487 {
 488         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
 489         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
 490 };
 491
 492 #ifdef CONFIG_SMP
 493 static inline int tasklet_trylock(struct tasklet_struct *t)
 494 {
 495         return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 496 }
 497
 498 static inline void tasklet_unlock(struct tasklet_struct *t)
 499 {
 500         smp_mb__before_atomic();
 501         clear_bit(TASKLET_STATE_RUN, &(t)->state);
 502 }
 503
 504 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 505 {
 506         while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
 507 }
 508 #else
 509 #define tasklet_trylock(t) 1
 510 #define tasklet_unlock_wait(t) do { } while (0)
 511 #define tasklet_unlock(t) do { } while (0)
 512 #endif
 513
 514 extern void __tasklet_schedule(struct tasklet_struct *t);
 515
 516 static inline void tasklet_schedule(struct tasklet_struct *t)
 517 {
 518         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 519                 __tasklet_schedule(t);
 520 }
 521
 522 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
 523
 524 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 525 {
 526         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 527                 __tasklet_hi_schedule(t);
 528 }
 529
 530 extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
 531
 532 /*
 533  * This version avoids touching any other tasklets. Needed for kmemcheck
 534  * in order not to take any page faults while enqueueing this tasklet;
 535  * consider VERY carefully whether you really need this or
 536  * tasklet_hi_schedule()...
 537  */
 538 static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
 539 {
 540         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 541                 __tasklet_hi_schedule_first(t);
 542 }
 543
 544
 545 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 546 {
 547         atomic_inc(&t->count);
 548         smp_mb__after_atomic();
 549 }
 550
 551 static inline void tasklet_disable(struct tasklet_struct *t)
 552 {
 553         tasklet_disable_nosync(t);
 554         tasklet_unlock_wait(t);
 555         smp_mb();
 556 }
 557
 558 static inline void tasklet_enable(struct tasklet_struct *t)
 559 {
 560         smp_mb__before_atomic();
 561         atomic_dec(&t->count);
 562 }
 563
 564 static inline void tasklet_hi_enable(struct tasklet_struct *t)
 565 {
 566         smp_mb__before_atomic();
 567         atomic_dec(&t->count);
 568 }
 569
 570 extern void tasklet_kill(struct tasklet_struct *t);
 571 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
 572 extern void tasklet_init(struct tasklet_struct *t,
 573                          void (*func)(unsigned long), unsigned long data);
 574
 575 struct tasklet_hrtimer {
 576         struct hrtimer          timer;
 577         struct tasklet_struct   tasklet;
 578         enum hrtimer_restart    (*function)(struct hrtimer *);
 579 };
 580
 581 extern void
 582 tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
 583                      enum hrtimer_restart (*function)(struct hrtimer *),
 584                      clockid_t which_clock, enum hrtimer_mode mode);
 585
 586 static inline
 587 int tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
 588                           const enum hrtimer_mode mode)
 589 {
 590         return hrtimer_start(&ttimer->timer, time, mode);
 591 }
 592
 593 static inline
 594 void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
 595 {
 596         hrtimer_cancel(&ttimer->timer);
 597         tasklet_kill(&ttimer->tasklet);
 598 }
 599
 600 /*
 601  * Autoprobing for irqs:
 602  *
 603  * probe_irq_on() and probe_irq_off() provide robust primitives
 604  * for accurate IRQ probing during kernel initialization.  They are
 605  * reasonably simple to use, are not "fooled" by spurious interrupts,
 606  * and, unlike other attempts at IRQ probing, they do not get hung on
 607  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
 608  *
 609  * For reasonably foolproof probing, use them as follows:
 610  *
 611  * 1. clear and/or mask the device's internal interrupt.
 612  * 2. sti();
 613  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
 614  * 4. enable the device and cause it to trigger an interrupt.
 615  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
 616  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
 617  * 7. service the device to clear its pending interrupt.
 618  * 8. loop again if paranoia is required.
 619  *
 620  * probe_irq_on() returns a mask of allocated irq's.
 621  *
 622  * probe_irq_off() takes the mask as a parameter,
 623  * and returns the irq number which occurred,
 624  * or zero if none occurred, or a negative irq number
 625  * if more than one irq occurred.
 626  */
 627
 628 #if !defined(CONFIG_GENERIC_IRQ_PROBE)
 629 static inline unsigned long probe_irq_on(void)
 630 {
 631         return 0;
 632 }
 633 static inline int probe_irq_off(unsigned long val)
 634 {
 635         return 0;
 636 }
 637 static inline unsigned int probe_irq_mask(unsigned long val)
 638 {
 639         return 0;
 640 }
 641 #else
 642 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
 643 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
 644 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
 645 #endif
 646
 647 #ifdef CONFIG_PROC_FS
 648 /* Initialize /proc/irq/ */
 649 extern void init_irq_proc(void);
 650 #else
 651 static inline void init_irq_proc(void)
 652 {
 653 }
 654 #endif
 655
 656 struct seq_file;
 657 int show_interrupts(struct seq_file *p, void *v);
 658 int arch_show_interrupts(struct seq_file *p, int prec);
 659
 660 extern int early_irq_init(void);
 661 extern int arch_probe_nr_irqs(void);
 662 extern int arch_early_irq_init(void);
 663
 664 #endif