2 * linux/kernel/irq/manage.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
7 * This file contains driver APIs to the irq subsystem.
10 #include <linux/irq.h>
11 #include <linux/kthread.h>
12 #include <linux/module.h>
13 #include <linux/random.h>
14 #include <linux/interrupt.h>
15 #include <linux/slab.h>
16 #include <linux/sched.h>
18 #include "internals.h"
21 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22 * @irq: interrupt number to wait for
24 * This function waits for any pending IRQ handlers for this interrupt
25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
28 * This function may be called - with care - from IRQ context.
30 void synchronize_irq(unsigned int irq
)
32 struct irq_desc
*desc
= irq_to_desc(irq
);
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
45 while (desc
->status
& IRQ_INPROGRESS
)
48 /* Ok, that indicated we're done: double-check carefully. */
49 spin_lock_irqsave(&desc
->lock
, flags
);
50 status
= desc
->status
;
51 spin_unlock_irqrestore(&desc
->lock
, flags
);
53 /* Oops, that failed? */
54 } while (status
& IRQ_INPROGRESS
);
57 * We made sure that no hardirq handler is running. Now verify
58 * that no threaded handlers are active.
60 wait_event(desc
->wait_for_threads
, !atomic_read(&desc
->threads_active
));
62 EXPORT_SYMBOL(synchronize_irq
);
65 cpumask_var_t irq_default_affinity
;
68 * irq_can_set_affinity - Check if the affinity of a given irq can be set
69 * @irq: Interrupt to check
72 int irq_can_set_affinity(unsigned int irq
)
74 struct irq_desc
*desc
= irq_to_desc(irq
);
76 if (CHECK_IRQ_PER_CPU(desc
->status
) || !desc
->chip
||
77 !desc
->chip
->set_affinity
)
84 * irq_set_thread_affinity - Notify irq threads to adjust affinity
85 * @desc: irq descriptor which has affitnity changed
87 * We just set IRQTF_AFFINITY and delegate the affinity setting
88 * to the interrupt thread itself. We can not call
89 * set_cpus_allowed_ptr() here as we hold desc->lock and this
90 * code can be called from hard interrupt context.
92 void irq_set_thread_affinity(struct irq_desc
*desc
)
94 struct irqaction
*action
= desc
->action
;
98 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
99 action
= action
->next
;
104 * irq_set_affinity - Set the irq affinity of a given irq
105 * @irq: Interrupt to set affinity
109 int irq_set_affinity(unsigned int irq
, const struct cpumask
*cpumask
)
111 struct irq_desc
*desc
= irq_to_desc(irq
);
114 if (!desc
->chip
->set_affinity
)
117 spin_lock_irqsave(&desc
->lock
, flags
);
119 #ifdef CONFIG_GENERIC_PENDING_IRQ
120 if (desc
->status
& IRQ_MOVE_PCNTXT
) {
121 if (!desc
->chip
->set_affinity(irq
, cpumask
)) {
122 cpumask_copy(desc
->affinity
, cpumask
);
123 irq_set_thread_affinity(desc
);
127 desc
->status
|= IRQ_MOVE_PENDING
;
128 cpumask_copy(desc
->pending_mask
, cpumask
);
131 if (!desc
->chip
->set_affinity(irq
, cpumask
)) {
132 cpumask_copy(desc
->affinity
, cpumask
);
133 irq_set_thread_affinity(desc
);
136 desc
->status
|= IRQ_AFFINITY_SET
;
137 spin_unlock_irqrestore(&desc
->lock
, flags
);
141 #ifndef CONFIG_AUTO_IRQ_AFFINITY
143 * Generic version of the affinity autoselector.
145 static int setup_affinity(unsigned int irq
, struct irq_desc
*desc
)
147 if (!irq_can_set_affinity(irq
))
151 * Preserve an userspace affinity setup, but make sure that
152 * one of the targets is online.
154 if (desc
->status
& (IRQ_AFFINITY_SET
| IRQ_NO_BALANCING
)) {
155 if (cpumask_any_and(desc
->affinity
, cpu_online_mask
)
159 desc
->status
&= ~IRQ_AFFINITY_SET
;
162 cpumask_and(desc
->affinity
, cpu_online_mask
, irq_default_affinity
);
164 desc
->chip
->set_affinity(irq
, desc
->affinity
);
169 static inline int setup_affinity(unsigned int irq
, struct irq_desc
*d
)
171 return irq_select_affinity(irq
);
176 * Called when affinity is set via /proc/irq
178 int irq_select_affinity_usr(unsigned int irq
)
180 struct irq_desc
*desc
= irq_to_desc(irq
);
184 spin_lock_irqsave(&desc
->lock
, flags
);
185 ret
= setup_affinity(irq
, desc
);
187 irq_set_thread_affinity(desc
);
188 spin_unlock_irqrestore(&desc
->lock
, flags
);
194 static inline int setup_affinity(unsigned int irq
, struct irq_desc
*desc
)
200 void __disable_irq(struct irq_desc
*desc
, unsigned int irq
, bool suspend
)
203 if (!desc
->action
|| (desc
->action
->flags
& IRQF_TIMER
))
205 desc
->status
|= IRQ_SUSPENDED
;
208 if (!desc
->depth
++) {
209 desc
->status
|= IRQ_DISABLED
;
210 desc
->chip
->disable(irq
);
215 * disable_irq_nosync - disable an irq without waiting
216 * @irq: Interrupt to disable
218 * Disable the selected interrupt line. Disables and Enables are
220 * Unlike disable_irq(), this function does not ensure existing
221 * instances of the IRQ handler have completed before returning.
223 * This function may be called from IRQ context.
225 void disable_irq_nosync(unsigned int irq
)
227 struct irq_desc
*desc
= irq_to_desc(irq
);
233 chip_bus_lock(irq
, desc
);
234 spin_lock_irqsave(&desc
->lock
, flags
);
235 __disable_irq(desc
, irq
, false);
236 spin_unlock_irqrestore(&desc
->lock
, flags
);
237 chip_bus_sync_unlock(irq
, desc
);
239 EXPORT_SYMBOL(disable_irq_nosync
);
242 * disable_irq - disable an irq and wait for completion
243 * @irq: Interrupt to disable
245 * Disable the selected interrupt line. Enables and Disables are
247 * This function waits for any pending IRQ handlers for this interrupt
248 * to complete before returning. If you use this function while
249 * holding a resource the IRQ handler may need you will deadlock.
251 * This function may be called - with care - from IRQ context.
253 void disable_irq(unsigned int irq
)
255 struct irq_desc
*desc
= irq_to_desc(irq
);
260 disable_irq_nosync(irq
);
262 synchronize_irq(irq
);
264 EXPORT_SYMBOL(disable_irq
);
266 void __enable_irq(struct irq_desc
*desc
, unsigned int irq
, bool resume
)
269 desc
->status
&= ~IRQ_SUSPENDED
;
271 switch (desc
->depth
) {
274 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
277 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
279 if (desc
->status
& IRQ_SUSPENDED
)
281 /* Prevent probing on this irq: */
282 desc
->status
= status
| IRQ_NOPROBE
;
283 check_irq_resend(desc
, irq
);
292 * enable_irq - enable handling of an irq
293 * @irq: Interrupt to enable
295 * Undoes the effect of one call to disable_irq(). If this
296 * matches the last disable, processing of interrupts on this
297 * IRQ line is re-enabled.
299 * This function may be called from IRQ context only when
300 * desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
302 void enable_irq(unsigned int irq
)
304 struct irq_desc
*desc
= irq_to_desc(irq
);
310 chip_bus_lock(irq
, desc
);
311 spin_lock_irqsave(&desc
->lock
, flags
);
312 __enable_irq(desc
, irq
, false);
313 spin_unlock_irqrestore(&desc
->lock
, flags
);
314 chip_bus_sync_unlock(irq
, desc
);
316 EXPORT_SYMBOL(enable_irq
);
318 static int set_irq_wake_real(unsigned int irq
, unsigned int on
)
320 struct irq_desc
*desc
= irq_to_desc(irq
);
323 if (desc
->chip
->set_wake
)
324 ret
= desc
->chip
->set_wake(irq
, on
);
330 * set_irq_wake - control irq power management wakeup
331 * @irq: interrupt to control
332 * @on: enable/disable power management wakeup
334 * Enable/disable power management wakeup mode, which is
335 * disabled by default. Enables and disables must match,
336 * just as they match for non-wakeup mode support.
338 * Wakeup mode lets this IRQ wake the system from sleep
339 * states like "suspend to RAM".
341 int set_irq_wake(unsigned int irq
, unsigned int on
)
343 struct irq_desc
*desc
= irq_to_desc(irq
);
347 /* wakeup-capable irqs can be shared between drivers that
348 * don't need to have the same sleep mode behaviors.
350 spin_lock_irqsave(&desc
->lock
, flags
);
352 if (desc
->wake_depth
++ == 0) {
353 ret
= set_irq_wake_real(irq
, on
);
355 desc
->wake_depth
= 0;
357 desc
->status
|= IRQ_WAKEUP
;
360 if (desc
->wake_depth
== 0) {
361 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
362 } else if (--desc
->wake_depth
== 0) {
363 ret
= set_irq_wake_real(irq
, on
);
365 desc
->wake_depth
= 1;
367 desc
->status
&= ~IRQ_WAKEUP
;
371 spin_unlock_irqrestore(&desc
->lock
, flags
);
374 EXPORT_SYMBOL(set_irq_wake
);
377 * Internal function that tells the architecture code whether a
378 * particular irq has been exclusively allocated or is available
381 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
383 struct irq_desc
*desc
= irq_to_desc(irq
);
384 struct irqaction
*action
;
389 if (desc
->status
& IRQ_NOREQUEST
)
392 action
= desc
->action
;
394 if (irqflags
& action
->flags
& IRQF_SHARED
)
400 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
403 * If the architecture still has not overriden
404 * the flow handler then zap the default. This
405 * should catch incorrect flow-type setting.
407 if (desc
->handle_irq
== &handle_bad_irq
)
408 desc
->handle_irq
= NULL
;
411 int __irq_set_trigger(struct irq_desc
*desc
, unsigned int irq
,
415 struct irq_chip
*chip
= desc
->chip
;
417 if (!chip
|| !chip
->set_type
) {
419 * IRQF_TRIGGER_* but the PIC does not support multiple
422 pr_debug("No set_type function for IRQ %d (%s)\n", irq
,
423 chip
? (chip
->name
? : "unknown") : "unknown");
427 /* caller masked out all except trigger mode flags */
428 ret
= chip
->set_type(irq
, flags
);
431 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
432 (int)flags
, irq
, chip
->set_type
);
434 if (flags
& (IRQ_TYPE_LEVEL_LOW
| IRQ_TYPE_LEVEL_HIGH
))
436 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
437 desc
->status
&= ~(IRQ_LEVEL
| IRQ_TYPE_SENSE_MASK
);
438 desc
->status
|= flags
;
445 * Default primary interrupt handler for threaded interrupts. Is
446 * assigned as primary handler when request_threaded_irq is called
447 * with handler == NULL. Useful for oneshot interrupts.
449 static irqreturn_t
irq_default_primary_handler(int irq
, void *dev_id
)
451 return IRQ_WAKE_THREAD
;
454 static int irq_wait_for_interrupt(struct irqaction
*action
)
456 while (!kthread_should_stop()) {
457 set_current_state(TASK_INTERRUPTIBLE
);
459 if (test_and_clear_bit(IRQTF_RUNTHREAD
,
460 &action
->thread_flags
)) {
461 __set_current_state(TASK_RUNNING
);
470 * Oneshot interrupts keep the irq line masked until the threaded
471 * handler finished. unmask if the interrupt has not been disabled and
474 static void irq_finalize_oneshot(unsigned int irq
, struct irq_desc
*desc
)
476 chip_bus_lock(irq
, desc
);
477 spin_lock_irq(&desc
->lock
);
478 if (!(desc
->status
& IRQ_DISABLED
) && (desc
->status
& IRQ_MASKED
)) {
479 desc
->status
&= ~IRQ_MASKED
;
480 desc
->chip
->unmask(irq
);
482 spin_unlock_irq(&desc
->lock
);
483 chip_bus_sync_unlock(irq
, desc
);
488 * Check whether we need to change the affinity of the interrupt thread.
491 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
)
495 if (!test_and_clear_bit(IRQTF_AFFINITY
, &action
->thread_flags
))
499 * In case we are out of memory we set IRQTF_AFFINITY again and
500 * try again next time
502 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
)) {
503 set_bit(IRQTF_AFFINITY
, &action
->thread_flags
);
507 spin_lock_irq(&desc
->lock
);
508 cpumask_copy(mask
, desc
->affinity
);
509 spin_unlock_irq(&desc
->lock
);
511 set_cpus_allowed_ptr(current
, mask
);
512 free_cpumask_var(mask
);
516 irq_thread_check_affinity(struct irq_desc
*desc
, struct irqaction
*action
) { }
520 * Interrupt handler thread
522 static int irq_thread(void *data
)
524 struct sched_param param
= { .sched_priority
= MAX_USER_RT_PRIO
/2, };
525 struct irqaction
*action
= data
;
526 struct irq_desc
*desc
= irq_to_desc(action
->irq
);
527 int wake
, oneshot
= desc
->status
& IRQ_ONESHOT
;
529 sched_setscheduler(current
, SCHED_FIFO
, ¶m
);
530 current
->irqaction
= action
;
532 while (!irq_wait_for_interrupt(action
)) {
534 irq_thread_check_affinity(desc
, action
);
536 atomic_inc(&desc
->threads_active
);
538 spin_lock_irq(&desc
->lock
);
539 if (unlikely(desc
->status
& IRQ_DISABLED
)) {
541 * CHECKME: We might need a dedicated
542 * IRQ_THREAD_PENDING flag here, which
543 * retriggers the thread in check_irq_resend()
544 * but AFAICT IRQ_PENDING should be fine as it
545 * retriggers the interrupt itself --- tglx
547 desc
->status
|= IRQ_PENDING
;
548 spin_unlock_irq(&desc
->lock
);
550 spin_unlock_irq(&desc
->lock
);
552 action
->thread_fn(action
->irq
, action
->dev_id
);
555 irq_finalize_oneshot(action
->irq
, desc
);
558 wake
= atomic_dec_and_test(&desc
->threads_active
);
560 if (wake
&& waitqueue_active(&desc
->wait_for_threads
))
561 wake_up(&desc
->wait_for_threads
);
565 * Clear irqaction. Otherwise exit_irq_thread() would make
566 * fuzz about an active irq thread going into nirvana.
568 current
->irqaction
= NULL
;
573 * Called from do_exit()
575 void exit_irq_thread(void)
577 struct task_struct
*tsk
= current
;
583 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
584 tsk
->comm
? tsk
->comm
: "", tsk
->pid
, tsk
->irqaction
->irq
);
587 * Set the THREAD DIED flag to prevent further wakeups of the
588 * soon to be gone threaded handler.
590 set_bit(IRQTF_DIED
, &tsk
->irqaction
->flags
);
594 * Internal function to register an irqaction - typically used to
595 * allocate special interrupts that are part of the architecture.
598 __setup_irq(unsigned int irq
, struct irq_desc
*desc
, struct irqaction
*new)
600 struct irqaction
*old
, **old_ptr
;
601 const char *old_name
= NULL
;
609 if (desc
->chip
== &no_irq_chip
)
612 * Some drivers like serial.c use request_irq() heavily,
613 * so we have to be careful not to interfere with a
616 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
618 * This function might sleep, we want to call it first,
619 * outside of the atomic block.
620 * Yes, this might clear the entropy pool if the wrong
621 * driver is attempted to be loaded, without actually
622 * installing a new handler, but is this really a problem,
623 * only the sysadmin is able to do this.
625 rand_initialize_irq(irq
);
628 /* Oneshot interrupts are not allowed with shared */
629 if ((new->flags
& IRQF_ONESHOT
) && (new->flags
& IRQF_SHARED
))
635 if (new->thread_fn
) {
636 struct task_struct
*t
;
638 t
= kthread_create(irq_thread
, new, "irq/%d-%s", irq
,
643 * We keep the reference to the task struct even if
644 * the thread dies to avoid that the interrupt code
645 * references an already freed task_struct.
653 * The following block of code has to be executed atomically
655 spin_lock_irqsave(&desc
->lock
, flags
);
656 old_ptr
= &desc
->action
;
660 * Can't share interrupts unless both agree to and are
661 * the same type (level, edge, polarity). So both flag
662 * fields must have IRQF_SHARED set and the bits which
663 * set the trigger type must match.
665 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
666 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
667 old_name
= old
->name
;
671 #if defined(CONFIG_IRQ_PER_CPU)
672 /* All handlers must agree on per-cpuness */
673 if ((old
->flags
& IRQF_PERCPU
) !=
674 (new->flags
& IRQF_PERCPU
))
678 /* add new interrupt at end of irq queue */
680 old_ptr
= &old
->next
;
687 irq_chip_set_defaults(desc
->chip
);
689 init_waitqueue_head(&desc
->wait_for_threads
);
691 /* Setup the type (level, edge polarity) if configured: */
692 if (new->flags
& IRQF_TRIGGER_MASK
) {
693 ret
= __irq_set_trigger(desc
, irq
,
694 new->flags
& IRQF_TRIGGER_MASK
);
699 compat_irq_chip_set_default_handler(desc
);
700 #if defined(CONFIG_IRQ_PER_CPU)
701 if (new->flags
& IRQF_PERCPU
)
702 desc
->status
|= IRQ_PER_CPU
;
705 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
| IRQ_ONESHOT
|
706 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
708 if (new->flags
& IRQF_ONESHOT
)
709 desc
->status
|= IRQ_ONESHOT
;
711 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
713 desc
->status
&= ~IRQ_DISABLED
;
714 desc
->chip
->startup(irq
);
716 /* Undo nested disables: */
719 /* Exclude IRQ from balancing if requested */
720 if (new->flags
& IRQF_NOBALANCING
)
721 desc
->status
|= IRQ_NO_BALANCING
;
723 /* Set default affinity mask once everything is setup */
724 setup_affinity(irq
, desc
);
726 } else if ((new->flags
& IRQF_TRIGGER_MASK
)
727 && (new->flags
& IRQF_TRIGGER_MASK
)
728 != (desc
->status
& IRQ_TYPE_SENSE_MASK
)) {
729 /* hope the handler works with the actual trigger mode... */
730 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
731 irq
, (int)(desc
->status
& IRQ_TYPE_SENSE_MASK
),
732 (int)(new->flags
& IRQF_TRIGGER_MASK
));
737 /* Reset broken irq detection when installing new handler */
739 desc
->irqs_unhandled
= 0;
742 * Check whether we disabled the irq via the spurious handler
743 * before. Reenable it and give it another chance.
745 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
746 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
747 __enable_irq(desc
, irq
, false);
750 spin_unlock_irqrestore(&desc
->lock
, flags
);
753 register_irq_proc(irq
, desc
);
755 register_handler_proc(irq
, new);
760 #ifdef CONFIG_DEBUG_SHIRQ
761 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
762 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
764 printk(KERN_ERR
"current handler: %s\n", old_name
);
771 spin_unlock_irqrestore(&desc
->lock
, flags
);
773 struct task_struct
*t
= new->thread
;
776 if (likely(!test_bit(IRQTF_DIED
, &new->thread_flags
)))
784 * setup_irq - setup an interrupt
785 * @irq: Interrupt line to setup
786 * @act: irqaction for the interrupt
788 * Used to statically setup interrupts in the early boot process.
790 int setup_irq(unsigned int irq
, struct irqaction
*act
)
792 struct irq_desc
*desc
= irq_to_desc(irq
);
794 return __setup_irq(irq
, desc
, act
);
796 EXPORT_SYMBOL_GPL(setup_irq
);
799 * Internal function to unregister an irqaction - used to free
800 * regular and special interrupts that are part of the architecture.
802 static struct irqaction
*__free_irq(unsigned int irq
, void *dev_id
)
804 struct irq_desc
*desc
= irq_to_desc(irq
);
805 struct irqaction
*action
, **action_ptr
;
808 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq
);
813 spin_lock_irqsave(&desc
->lock
, flags
);
816 * There can be multiple actions per IRQ descriptor, find the right
817 * one based on the dev_id:
819 action_ptr
= &desc
->action
;
821 action
= *action_ptr
;
824 WARN(1, "Trying to free already-free IRQ %d\n", irq
);
825 spin_unlock_irqrestore(&desc
->lock
, flags
);
830 if (action
->dev_id
== dev_id
)
832 action_ptr
= &action
->next
;
835 /* Found it - now remove it from the list of entries: */
836 *action_ptr
= action
->next
;
838 /* Currently used only by UML, might disappear one day: */
839 #ifdef CONFIG_IRQ_RELEASE_METHOD
840 if (desc
->chip
->release
)
841 desc
->chip
->release(irq
, dev_id
);
844 /* If this was the last handler, shut down the IRQ line: */
846 desc
->status
|= IRQ_DISABLED
;
847 if (desc
->chip
->shutdown
)
848 desc
->chip
->shutdown(irq
);
850 desc
->chip
->disable(irq
);
853 spin_unlock_irqrestore(&desc
->lock
, flags
);
855 unregister_handler_proc(irq
, action
);
857 /* Make sure it's not being used on another CPU: */
858 synchronize_irq(irq
);
860 #ifdef CONFIG_DEBUG_SHIRQ
862 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
863 * event to happen even now it's being freed, so let's make sure that
864 * is so by doing an extra call to the handler ....
866 * ( We do this after actually deregistering it, to make sure that a
867 * 'real' IRQ doesn't run in * parallel with our fake. )
869 if (action
->flags
& IRQF_SHARED
) {
870 local_irq_save(flags
);
871 action
->handler(irq
, dev_id
);
872 local_irq_restore(flags
);
876 if (action
->thread
) {
877 if (!test_bit(IRQTF_DIED
, &action
->thread_flags
))
878 kthread_stop(action
->thread
);
879 put_task_struct(action
->thread
);
886 * remove_irq - free an interrupt
887 * @irq: Interrupt line to free
888 * @act: irqaction for the interrupt
890 * Used to remove interrupts statically setup by the early boot process.
892 void remove_irq(unsigned int irq
, struct irqaction
*act
)
894 __free_irq(irq
, act
->dev_id
);
896 EXPORT_SYMBOL_GPL(remove_irq
);
899 * free_irq - free an interrupt allocated with request_irq
900 * @irq: Interrupt line to free
901 * @dev_id: Device identity to free
903 * Remove an interrupt handler. The handler is removed and if the
904 * interrupt line is no longer in use by any driver it is disabled.
905 * On a shared IRQ the caller must ensure the interrupt is disabled
906 * on the card it drives before calling this function. The function
907 * does not return until any executing interrupts for this IRQ
910 * This function must not be called from interrupt context.
912 void free_irq(unsigned int irq
, void *dev_id
)
914 struct irq_desc
*desc
= irq_to_desc(irq
);
919 chip_bus_lock(irq
, desc
);
920 kfree(__free_irq(irq
, dev_id
));
921 chip_bus_sync_unlock(irq
, desc
);
923 EXPORT_SYMBOL(free_irq
);
926 * request_threaded_irq - allocate an interrupt line
927 * @irq: Interrupt line to allocate
928 * @handler: Function to be called when the IRQ occurs.
929 * Primary handler for threaded interrupts
930 * If NULL and thread_fn != NULL the default
931 * primary handler is installed
932 * @thread_fn: Function called from the irq handler thread
933 * If NULL, no irq thread is created
934 * @irqflags: Interrupt type flags
935 * @devname: An ascii name for the claiming device
936 * @dev_id: A cookie passed back to the handler function
938 * This call allocates interrupt resources and enables the
939 * interrupt line and IRQ handling. From the point this
940 * call is made your handler function may be invoked. Since
941 * your handler function must clear any interrupt the board
942 * raises, you must take care both to initialise your hardware
943 * and to set up the interrupt handler in the right order.
945 * If you want to set up a threaded irq handler for your device
946 * then you need to supply @handler and @thread_fn. @handler ist
947 * still called in hard interrupt context and has to check
948 * whether the interrupt originates from the device. If yes it
949 * needs to disable the interrupt on the device and return
950 * IRQ_WAKE_THREAD which will wake up the handler thread and run
951 * @thread_fn. This split handler design is necessary to support
954 * Dev_id must be globally unique. Normally the address of the
955 * device data structure is used as the cookie. Since the handler
956 * receives this value it makes sense to use it.
958 * If your interrupt is shared you must pass a non NULL dev_id
959 * as this is required when freeing the interrupt.
963 * IRQF_SHARED Interrupt is shared
964 * IRQF_DISABLED Disable local interrupts while processing
965 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
966 * IRQF_TRIGGER_* Specify active edge(s) or level
969 int request_threaded_irq(unsigned int irq
, irq_handler_t handler
,
970 irq_handler_t thread_fn
, unsigned long irqflags
,
971 const char *devname
, void *dev_id
)
973 struct irqaction
*action
;
974 struct irq_desc
*desc
;
978 * handle_IRQ_event() always ignores IRQF_DISABLED except for
979 * the _first_ irqaction (sigh). That can cause oopsing, but
980 * the behavior is classified as "will not fix" so we need to
981 * start nudging drivers away from using that idiom.
983 if ((irqflags
& (IRQF_SHARED
|IRQF_DISABLED
)) ==
984 (IRQF_SHARED
|IRQF_DISABLED
)) {
986 "IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
990 #ifdef CONFIG_LOCKDEP
992 * Lockdep wants atomic interrupt handlers:
994 irqflags
|= IRQF_DISABLED
;
997 * Sanity-check: shared interrupts must pass in a real dev-ID,
998 * otherwise we'll have trouble later trying to figure out
999 * which interrupt is which (messes up the interrupt freeing
1002 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
1005 desc
= irq_to_desc(irq
);
1009 if (desc
->status
& IRQ_NOREQUEST
)
1015 handler
= irq_default_primary_handler
;
1018 action
= kzalloc(sizeof(struct irqaction
), GFP_KERNEL
);
1022 action
->handler
= handler
;
1023 action
->thread_fn
= thread_fn
;
1024 action
->flags
= irqflags
;
1025 action
->name
= devname
;
1026 action
->dev_id
= dev_id
;
1028 chip_bus_lock(irq
, desc
);
1029 retval
= __setup_irq(irq
, desc
, action
);
1030 chip_bus_sync_unlock(irq
, desc
);
1035 #ifdef CONFIG_DEBUG_SHIRQ
1036 if (irqflags
& IRQF_SHARED
) {
1038 * It's a shared IRQ -- the driver ought to be prepared for it
1039 * to happen immediately, so let's make sure....
1040 * We disable the irq to make sure that a 'real' IRQ doesn't
1041 * run in parallel with our fake.
1043 unsigned long flags
;
1046 local_irq_save(flags
);
1048 handler(irq
, dev_id
);
1050 local_irq_restore(flags
);
1056 EXPORT_SYMBOL(request_threaded_irq
);