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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 #include <asm/sections.h>
22
23 /*
24 * These correspond to the IORESOURCE_IRQ_* defines in
25 * linux/ioport.h to select the interrupt line behaviour. When
26 * requesting an interrupt without specifying a IRQF_TRIGGER, the
27 * setting should be assumed to be "as already configured", which
28 * may be as per machine or firmware initialisation.
29 */
30 #define IRQF_TRIGGER_NONE 0x00000000
31 #define IRQF_TRIGGER_RISING 0x00000001
32 #define IRQF_TRIGGER_FALLING 0x00000002
33 #define IRQF_TRIGGER_HIGH 0x00000004
34 #define IRQF_TRIGGER_LOW 0x00000008
35 #define IRQF_TRIGGER_MASK (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
36 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
37 #define IRQF_TRIGGER_PROBE 0x00000010
38
39 /*
40 * These flags used only by the kernel as part of the
41 * irq handling routines.
42 *
43 * IRQF_SHARED - allow sharing the irq among several devices
44 * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
45 * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
46 * IRQF_PERCPU - Interrupt is per cpu
47 * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
48 * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
49 * registered first in an shared interrupt is considered for
50 * performance reasons)
51 * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
52 * Used by threaded interrupts which need to keep the
53 * irq line disabled until the threaded handler has been run.
54 * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend. Does not guarantee
55 * that this interrupt will wake the system from a suspended
56 * state. See Documentation/power/suspend-and-interrupts.txt
57 * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
58 * IRQF_NO_THREAD - Interrupt cannot be threaded
59 * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
60 * resume time.
61 * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this
62 * interrupt handler after suspending interrupts. For system
63 * wakeup devices users need to implement wakeup detection in
64 * their interrupt handlers.
65 */
66 #define IRQF_SHARED 0x00000080
67 #define IRQF_PROBE_SHARED 0x00000100
68 #define __IRQF_TIMER 0x00000200
69 #define IRQF_PERCPU 0x00000400
70 #define IRQF_NOBALANCING 0x00000800
71 #define IRQF_IRQPOLL 0x00001000
72 #define IRQF_ONESHOT 0x00002000
73 #define IRQF_NO_SUSPEND 0x00004000
74 #define IRQF_FORCE_RESUME 0x00008000
75 #define IRQF_NO_THREAD 0x00010000
76 #define IRQF_EARLY_RESUME 0x00020000
77 #define IRQF_COND_SUSPEND 0x00040000
78
79 #define IRQF_TIMER (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
80
81 /*
82 * These values can be returned by request_any_context_irq() and
83 * describe the context the interrupt will be run in.
84 *
85 * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
86 * IRQC_IS_NESTED - interrupt runs in a nested threaded context
87 */
88 enum {
89 IRQC_IS_HARDIRQ = 0,
90 IRQC_IS_NESTED,
91 };
92
93 typedef irqreturn_t (*irq_handler_t)(int, void *);
94
95 /**
96 * struct irqaction - per interrupt action descriptor
97 * @handler: interrupt handler function
98 * @name: name of the device
99 * @dev_id: cookie to identify the device
100 * @percpu_dev_id: cookie to identify the device
101 * @next: pointer to the next irqaction for shared interrupts
102 * @irq: interrupt number
103 * @flags: flags (see IRQF_* above)
104 * @thread_fn: interrupt handler function for threaded interrupts
105 * @thread: thread pointer for threaded interrupts
106 * @secondary: pointer to secondary irqaction (force threading)
107 * @thread_flags: flags related to @thread
108 * @thread_mask: bitmask for keeping track of @thread activity
109 * @dir: pointer to the proc/irq/NN/name entry
110 */
111 struct irqaction {
112 irq_handler_t handler;
113 void *dev_id;
114 void __percpu *percpu_dev_id;
115 struct irqaction *next;
116 irq_handler_t thread_fn;
117 struct task_struct *thread;
118 struct irqaction *secondary;
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 /*
130 * If a (PCI) device interrupt is not connected we set dev->irq to
131 * IRQ_NOTCONNECTED. This causes request_irq() to fail with -ENOTCONN, so we
132 * can distingiush that case from other error returns.
133 *
134 * 0x80000000 is guaranteed to be outside the available range of interrupts
135 * and easy to distinguish from other possible incorrect values.
136 */
137 #define IRQ_NOTCONNECTED (1U << 31)
138
139 extern int __must_check
140 request_threaded_irq(unsigned int irq, irq_handler_t handler,
141 irq_handler_t thread_fn,
142 unsigned long flags, const char *name, void *dev);
143
144 static inline int __must_check
145 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
146 const char *name, void *dev)
147 {
148 return request_threaded_irq(irq, handler, NULL, flags, name, dev);
149 }
150
151 extern int __must_check
152 request_any_context_irq(unsigned int irq, irq_handler_t handler,
153 unsigned long flags, const char *name, void *dev_id);
154
155 extern int __must_check
156 __request_percpu_irq(unsigned int irq, irq_handler_t handler,
157 unsigned long flags, const char *devname,
158 void __percpu *percpu_dev_id);
159
160 static inline int __must_check
161 request_percpu_irq(unsigned int irq, irq_handler_t handler,
162 const char *devname, void __percpu *percpu_dev_id)
163 {
164 return __request_percpu_irq(irq, handler, 0,
165 devname, percpu_dev_id);
166 }
167
168 extern const void *free_irq(unsigned int, void *);
169 extern void free_percpu_irq(unsigned int, void __percpu *);
170
171 struct device;
172
173 extern int __must_check
174 devm_request_threaded_irq(struct device *dev, unsigned int irq,
175 irq_handler_t handler, irq_handler_t thread_fn,
176 unsigned long irqflags, const char *devname,
177 void *dev_id);
178
179 static inline int __must_check
180 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
181 unsigned long irqflags, const char *devname, void *dev_id)
182 {
183 return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
184 devname, dev_id);
185 }
186
187 extern int __must_check
188 devm_request_any_context_irq(struct device *dev, unsigned int irq,
189 irq_handler_t handler, unsigned long irqflags,
190 const char *devname, void *dev_id);
191
192 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
193
194 /*
195 * On lockdep we dont want to enable hardirqs in hardirq
196 * context. Use local_irq_enable_in_hardirq() to annotate
197 * kernel code that has to do this nevertheless (pretty much
198 * the only valid case is for old/broken hardware that is
199 * insanely slow).
200 *
201 * NOTE: in theory this might break fragile code that relies
202 * on hardirq delivery - in practice we dont seem to have such
203 * places left. So the only effect should be slightly increased
204 * irqs-off latencies.
205 */
206 #ifdef CONFIG_LOCKDEP
207 # define local_irq_enable_in_hardirq() do { } while (0)
208 #else
209 # define local_irq_enable_in_hardirq() local_irq_enable()
210 #endif
211
212 extern void disable_irq_nosync(unsigned int irq);
213 extern bool disable_hardirq(unsigned int irq);
214 extern void disable_irq(unsigned int irq);
215 extern void disable_percpu_irq(unsigned int irq);
216 extern void enable_irq(unsigned int irq);
217 extern void enable_percpu_irq(unsigned int irq, unsigned int type);
218 extern bool irq_percpu_is_enabled(unsigned int irq);
219 extern void irq_wake_thread(unsigned int irq, void *dev_id);
220
221 /* The following three functions are for the core kernel use only. */
222 extern void suspend_device_irqs(void);
223 extern void resume_device_irqs(void);
224
225 /**
226 * struct irq_affinity_notify - context for notification of IRQ affinity changes
227 * @irq: Interrupt to which notification applies
228 * @kref: Reference count, for internal use
229 * @work: Work item, for internal use
230 * @notify: Function to be called on change. This will be
231 * called in process context.
232 * @release: Function to be called on release. This will be
233 * called in process context. Once registered, the
234 * structure must only be freed when this function is
235 * called or later.
236 */
237 struct irq_affinity_notify {
238 unsigned int irq;
239 struct kref kref;
240 struct work_struct work;
241 void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
242 void (*release)(struct kref *ref);
243 };
244
245 /**
246 * struct irq_affinity - Description for automatic irq affinity assignements
247 * @pre_vectors: Don't apply affinity to @pre_vectors at beginning of
248 * the MSI(-X) vector space
249 * @post_vectors: Don't apply affinity to @post_vectors at end of
250 * the MSI(-X) vector space
251 */
252 struct irq_affinity {
253 int pre_vectors;
254 int post_vectors;
255 };
256
257 #if defined(CONFIG_SMP)
258
259 extern cpumask_var_t irq_default_affinity;
260
261 /* Internal implementation. Use the helpers below */
262 extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask,
263 bool force);
264
265 /**
266 * irq_set_affinity - Set the irq affinity of a given irq
267 * @irq: Interrupt to set affinity
268 * @cpumask: cpumask
269 *
270 * Fails if cpumask does not contain an online CPU
271 */
272 static inline int
273 irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
274 {
275 return __irq_set_affinity(irq, cpumask, false);
276 }
277
278 /**
279 * irq_force_affinity - Force the irq affinity of a given irq
280 * @irq: Interrupt to set affinity
281 * @cpumask: cpumask
282 *
283 * Same as irq_set_affinity, but without checking the mask against
284 * online cpus.
285 *
286 * Solely for low level cpu hotplug code, where we need to make per
287 * cpu interrupts affine before the cpu becomes online.
288 */
289 static inline int
290 irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
291 {
292 return __irq_set_affinity(irq, cpumask, true);
293 }
294
295 extern int irq_can_set_affinity(unsigned int irq);
296 extern int irq_select_affinity(unsigned int irq);
297
298 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
299
300 extern int
301 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
302
303 struct cpumask *irq_create_affinity_masks(int nvec, const struct irq_affinity *affd);
304 int irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd);
305
306 #else /* CONFIG_SMP */
307
308 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
309 {
310 return -EINVAL;
311 }
312
313 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
314 {
315 return 0;
316 }
317
318 static inline int irq_can_set_affinity(unsigned int irq)
319 {
320 return 0;
321 }
322
323 static inline int irq_select_affinity(unsigned int irq) { return 0; }
324
325 static inline int irq_set_affinity_hint(unsigned int irq,
326 const struct cpumask *m)
327 {
328 return -EINVAL;
329 }
330
331 static inline int
332 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
333 {
334 return 0;
335 }
336
337 static inline struct cpumask *
338 irq_create_affinity_masks(int nvec, const struct irq_affinity *affd)
339 {
340 return NULL;
341 }
342
343 static inline int
344 irq_calc_affinity_vectors(int minvec, int maxvec, const struct irq_affinity *affd)
345 {
346 return maxvec;
347 }
348
349 #endif /* CONFIG_SMP */
350
351 /*
352 * Special lockdep variants of irq disabling/enabling.
353 * These should be used for locking constructs that
354 * know that a particular irq context which is disabled,
355 * and which is the only irq-context user of a lock,
356 * that it's safe to take the lock in the irq-disabled
357 * section without disabling hardirqs.
358 *
359 * On !CONFIG_LOCKDEP they are equivalent to the normal
360 * irq disable/enable methods.
361 */
362 static inline void disable_irq_nosync_lockdep(unsigned int irq)
363 {
364 disable_irq_nosync(irq);
365 #ifdef CONFIG_LOCKDEP
366 local_irq_disable();
367 #endif
368 }
369
370 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
371 {
372 disable_irq_nosync(irq);
373 #ifdef CONFIG_LOCKDEP
374 local_irq_save(*flags);
375 #endif
376 }
377
378 static inline void disable_irq_lockdep(unsigned int irq)
379 {
380 disable_irq(irq);
381 #ifdef CONFIG_LOCKDEP
382 local_irq_disable();
383 #endif
384 }
385
386 static inline void enable_irq_lockdep(unsigned int irq)
387 {
388 #ifdef CONFIG_LOCKDEP
389 local_irq_enable();
390 #endif
391 enable_irq(irq);
392 }
393
394 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
395 {
396 #ifdef CONFIG_LOCKDEP
397 local_irq_restore(*flags);
398 #endif
399 enable_irq(irq);
400 }
401
402 /* IRQ wakeup (PM) control: */
403 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
404
405 static inline int enable_irq_wake(unsigned int irq)
406 {
407 return irq_set_irq_wake(irq, 1);
408 }
409
410 static inline int disable_irq_wake(unsigned int irq)
411 {
412 return irq_set_irq_wake(irq, 0);
413 }
414
415 /*
416 * irq_get_irqchip_state/irq_set_irqchip_state specific flags
417 */
418 enum irqchip_irq_state {
419 IRQCHIP_STATE_PENDING, /* Is interrupt pending? */
420 IRQCHIP_STATE_ACTIVE, /* Is interrupt in progress? */
421 IRQCHIP_STATE_MASKED, /* Is interrupt masked? */
422 IRQCHIP_STATE_LINE_LEVEL, /* Is IRQ line high? */
423 };
424
425 extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
426 bool *state);
427 extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
428 bool state);
429
430 #ifdef CONFIG_IRQ_FORCED_THREADING
431 extern bool force_irqthreads;
432 #else
433 #define force_irqthreads (0)
434 #endif
435
436 #ifndef __ARCH_SET_SOFTIRQ_PENDING
437 #define set_softirq_pending(x) (local_softirq_pending() = (x))
438 #define or_softirq_pending(x) (local_softirq_pending() |= (x))
439 #endif
440
441 /* Some architectures might implement lazy enabling/disabling of
442 * interrupts. In some cases, such as stop_machine, we might want
443 * to ensure that after a local_irq_disable(), interrupts have
444 * really been disabled in hardware. Such architectures need to
445 * implement the following hook.
446 */
447 #ifndef hard_irq_disable
448 #define hard_irq_disable() do { } while(0)
449 #endif
450
451 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
452 frequency threaded job scheduling. For almost all the purposes
453 tasklets are more than enough. F.e. all serial device BHs et
454 al. should be converted to tasklets, not to softirqs.
455 */
456
457 enum
458 {
459 HI_SOFTIRQ=0,
460 TIMER_SOFTIRQ,
461 NET_TX_SOFTIRQ,
462 NET_RX_SOFTIRQ,
463 BLOCK_SOFTIRQ,
464 IRQ_POLL_SOFTIRQ,
465 TASKLET_SOFTIRQ,
466 SCHED_SOFTIRQ,
467 HRTIMER_SOFTIRQ, /* Unused, but kept as tools rely on the
468 numbering. Sigh! */
469 RCU_SOFTIRQ, /* Preferable RCU should always be the last softirq */
470
471 NR_SOFTIRQS
472 };
473
474 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
475
476 /* map softirq index to softirq name. update 'softirq_to_name' in
477 * kernel/softirq.c when adding a new softirq.
478 */
479 extern const char * const softirq_to_name[NR_SOFTIRQS];
480
481 /* softirq mask and active fields moved to irq_cpustat_t in
482 * asm/hardirq.h to get better cache usage. KAO
483 */
484
485 struct softirq_action
486 {
487 void (*action)(struct softirq_action *);
488 };
489
490 asmlinkage void do_softirq(void);
491 asmlinkage void __do_softirq(void);
492
493 #ifdef __ARCH_HAS_DO_SOFTIRQ
494 void do_softirq_own_stack(void);
495 #else
496 static inline void do_softirq_own_stack(void)
497 {
498 __do_softirq();
499 }
500 #endif
501
502 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
503 extern void softirq_init(void);
504 extern void __raise_softirq_irqoff(unsigned int nr);
505
506 extern void raise_softirq_irqoff(unsigned int nr);
507 extern void raise_softirq(unsigned int nr);
508
509 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
510
511 static inline struct task_struct *this_cpu_ksoftirqd(void)
512 {
513 return this_cpu_read(ksoftirqd);
514 }
515
516 /* Tasklets --- multithreaded analogue of BHs.
517
518 Main feature differing them of generic softirqs: tasklet
519 is running only on one CPU simultaneously.
520
521 Main feature differing them of BHs: different tasklets
522 may be run simultaneously on different CPUs.
523
524 Properties:
525 * If tasklet_schedule() is called, then tasklet is guaranteed
526 to be executed on some cpu at least once after this.
527 * If the tasklet is already scheduled, but its execution is still not
528 started, it will be executed only once.
529 * If this tasklet is already running on another CPU (or schedule is called
530 from tasklet itself), it is rescheduled for later.
531 * Tasklet is strictly serialized wrt itself, but not
532 wrt another tasklets. If client needs some intertask synchronization,
533 he makes it with spinlocks.
534 */
535
536 struct tasklet_struct
537 {
538 struct tasklet_struct *next;
539 unsigned long state;
540 atomic_t count;
541 void (*func)(unsigned long);
542 unsigned long data;
543 };
544
545 #define DECLARE_TASKLET(name, func, data) \
546 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
547
548 #define DECLARE_TASKLET_DISABLED(name, func, data) \
549 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
550
551
552 enum
553 {
554 TASKLET_STATE_SCHED, /* Tasklet is scheduled for execution */
555 TASKLET_STATE_RUN /* Tasklet is running (SMP only) */
556 };
557
558 #ifdef CONFIG_SMP
559 static inline int tasklet_trylock(struct tasklet_struct *t)
560 {
561 return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
562 }
563
564 static inline void tasklet_unlock(struct tasklet_struct *t)
565 {
566 smp_mb__before_atomic();
567 clear_bit(TASKLET_STATE_RUN, &(t)->state);
568 }
569
570 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
571 {
572 while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
573 }
574 #else
575 #define tasklet_trylock(t) 1
576 #define tasklet_unlock_wait(t) do { } while (0)
577 #define tasklet_unlock(t) do { } while (0)
578 #endif
579
580 extern void __tasklet_schedule(struct tasklet_struct *t);
581
582 static inline void tasklet_schedule(struct tasklet_struct *t)
583 {
584 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
585 __tasklet_schedule(t);
586 }
587
588 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
589
590 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
591 {
592 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
593 __tasklet_hi_schedule(t);
594 }
595
596 extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
597
598 /*
599 * This version avoids touching any other tasklets. Needed for kmemcheck
600 * in order not to take any page faults while enqueueing this tasklet;
601 * consider VERY carefully whether you really need this or
602 * tasklet_hi_schedule()...
603 */
604 static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
605 {
606 if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
607 __tasklet_hi_schedule_first(t);
608 }
609
610
611 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
612 {
613 atomic_inc(&t->count);
614 smp_mb__after_atomic();
615 }
616
617 static inline void tasklet_disable(struct tasklet_struct *t)
618 {
619 tasklet_disable_nosync(t);
620 tasklet_unlock_wait(t);
621 smp_mb();
622 }
623
624 static inline void tasklet_enable(struct tasklet_struct *t)
625 {
626 smp_mb__before_atomic();
627 atomic_dec(&t->count);
628 }
629
630 extern void tasklet_kill(struct tasklet_struct *t);
631 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
632 extern void tasklet_init(struct tasklet_struct *t,
633 void (*func)(unsigned long), unsigned long data);
634
635 struct tasklet_hrtimer {
636 struct hrtimer timer;
637 struct tasklet_struct tasklet;
638 enum hrtimer_restart (*function)(struct hrtimer *);
639 };
640
641 extern void
642 tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
643 enum hrtimer_restart (*function)(struct hrtimer *),
644 clockid_t which_clock, enum hrtimer_mode mode);
645
646 static inline
647 void tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
648 const enum hrtimer_mode mode)
649 {
650 hrtimer_start(&ttimer->timer, time, mode);
651 }
652
653 static inline
654 void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
655 {
656 hrtimer_cancel(&ttimer->timer);
657 tasklet_kill(&ttimer->tasklet);
658 }
659
660 /*
661 * Autoprobing for irqs:
662 *
663 * probe_irq_on() and probe_irq_off() provide robust primitives
664 * for accurate IRQ probing during kernel initialization. They are
665 * reasonably simple to use, are not "fooled" by spurious interrupts,
666 * and, unlike other attempts at IRQ probing, they do not get hung on
667 * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
668 *
669 * For reasonably foolproof probing, use them as follows:
670 *
671 * 1. clear and/or mask the device's internal interrupt.
672 * 2. sti();
673 * 3. irqs = probe_irq_on(); // "take over" all unassigned idle IRQs
674 * 4. enable the device and cause it to trigger an interrupt.
675 * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
676 * 6. irq = probe_irq_off(irqs); // get IRQ number, 0=none, negative=multiple
677 * 7. service the device to clear its pending interrupt.
678 * 8. loop again if paranoia is required.
679 *
680 * probe_irq_on() returns a mask of allocated irq's.
681 *
682 * probe_irq_off() takes the mask as a parameter,
683 * and returns the irq number which occurred,
684 * or zero if none occurred, or a negative irq number
685 * if more than one irq occurred.
686 */
687
688 #if !defined(CONFIG_GENERIC_IRQ_PROBE)
689 static inline unsigned long probe_irq_on(void)
690 {
691 return 0;
692 }
693 static inline int probe_irq_off(unsigned long val)
694 {
695 return 0;
696 }
697 static inline unsigned int probe_irq_mask(unsigned long val)
698 {
699 return 0;
700 }
701 #else
702 extern unsigned long probe_irq_on(void); /* returns 0 on failure */
703 extern int probe_irq_off(unsigned long); /* returns 0 or negative on failure */
704 extern unsigned int probe_irq_mask(unsigned long); /* returns mask of ISA interrupts */
705 #endif
706
707 #ifdef CONFIG_PROC_FS
708 /* Initialize /proc/irq/ */
709 extern void init_irq_proc(void);
710 #else
711 static inline void init_irq_proc(void)
712 {
713 }
714 #endif
715
716 #ifdef CONFIG_IRQ_TIMINGS
717 void irq_timings_enable(void);
718 void irq_timings_disable(void);
719 u64 irq_timings_next_event(u64 now);
720 #endif
721
722 struct seq_file;
723 int show_interrupts(struct seq_file *p, void *v);
724 int arch_show_interrupts(struct seq_file *p, int prec);
725
726 extern int early_irq_init(void);
727 extern int arch_probe_nr_irqs(void);
728 extern int arch_early_irq_init(void);
729
730 /*
731 * We want to know which function is an entrypoint of a hardirq or a softirq.
732 */
733 #define __irq_entry __attribute__((__section__(".irqentry.text")))
734 #define __softirq_entry \
735 __attribute__((__section__(".softirqentry.text")))
736
737 #endif