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 raw_spin_lock_irqsave(&desc->lock, flags);
50 status = desc->status;
51 raw_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->irq_data.chip ||
77 !desc->irq_data.chip->irq_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);
112 struct irq_chip *chip = desc->irq_data.chip;
115 if (!chip->irq_set_affinity)
118 raw_spin_lock_irqsave(&desc->lock, flags);
120 #ifdef CONFIG_GENERIC_PENDING_IRQ
121 if (desc->status & IRQ_MOVE_PCNTXT) {
122 if (!chip->irq_set_affinity(&desc->irq_data, cpumask, false)) {
123 cpumask_copy(desc->irq_data.affinity, cpumask);
124 irq_set_thread_affinity(desc);
128 desc->status |= IRQ_MOVE_PENDING;
129 cpumask_copy(desc->pending_mask, cpumask);
132 if (!chip->irq_set_affinity(&desc->irq_data, cpumask, false)) {
133 cpumask_copy(desc->irq_data.affinity, cpumask);
134 irq_set_thread_affinity(desc);
137 desc->status |= IRQ_AFFINITY_SET;
138 raw_spin_unlock_irqrestore(&desc->lock, flags);
142 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
144 struct irq_desc *desc = irq_to_desc(irq);
150 raw_spin_lock_irqsave(&desc->lock, flags);
151 desc->affinity_hint = m;
152 raw_spin_unlock_irqrestore(&desc->lock, flags);
156 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
158 #ifndef CONFIG_AUTO_IRQ_AFFINITY
160 * Generic version of the affinity autoselector.
162 static int setup_affinity(unsigned int irq, struct irq_desc *desc)
164 if (!irq_can_set_affinity(irq))
168 * Preserve an userspace affinity setup, but make sure that
169 * one of the targets is online.
171 if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
172 if (cpumask_any_and(desc->irq_data.affinity, cpu_online_mask)
176 desc->status &= ~IRQ_AFFINITY_SET;
179 cpumask_and(desc->irq_data.affinity, cpu_online_mask, irq_default_affinity);
181 desc->irq_data.chip->irq_set_affinity(&desc->irq_data, desc->irq_data.affinity, false);
186 static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
188 return irq_select_affinity(irq);
193 * Called when affinity is set via /proc/irq
195 int irq_select_affinity_usr(unsigned int irq)
197 struct irq_desc *desc = irq_to_desc(irq);
201 raw_spin_lock_irqsave(&desc->lock, flags);
202 ret = setup_affinity(irq, desc);
204 irq_set_thread_affinity(desc);
205 raw_spin_unlock_irqrestore(&desc->lock, flags);
211 static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
217 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
220 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
222 desc->status |= IRQ_SUSPENDED;
225 if (!desc->depth++) {
226 desc->status |= IRQ_DISABLED;
227 desc->irq_data.chip->irq_disable(&desc->irq_data);
232 * disable_irq_nosync - disable an irq without waiting
233 * @irq: Interrupt to disable
235 * Disable the selected interrupt line. Disables and Enables are
237 * Unlike disable_irq(), this function does not ensure existing
238 * instances of the IRQ handler have completed before returning.
240 * This function may be called from IRQ context.
242 void disable_irq_nosync(unsigned int irq)
244 struct irq_desc *desc = irq_to_desc(irq);
251 raw_spin_lock_irqsave(&desc->lock, flags);
252 __disable_irq(desc, irq, false);
253 raw_spin_unlock_irqrestore(&desc->lock, flags);
254 chip_bus_sync_unlock(desc);
256 EXPORT_SYMBOL(disable_irq_nosync);
259 * disable_irq - disable an irq and wait for completion
260 * @irq: Interrupt to disable
262 * Disable the selected interrupt line. Enables and Disables are
264 * This function waits for any pending IRQ handlers for this interrupt
265 * to complete before returning. If you use this function while
266 * holding a resource the IRQ handler may need you will deadlock.
268 * This function may be called - with care - from IRQ context.
270 void disable_irq(unsigned int irq)
272 struct irq_desc *desc = irq_to_desc(irq);
277 disable_irq_nosync(irq);
279 synchronize_irq(irq);
281 EXPORT_SYMBOL(disable_irq);
283 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
286 desc->status &= ~IRQ_SUSPENDED;
288 switch (desc->depth) {
291 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
294 unsigned int status = desc->status & ~IRQ_DISABLED;
296 if (desc->status & IRQ_SUSPENDED)
298 /* Prevent probing on this irq: */
299 desc->status = status | IRQ_NOPROBE;
300 check_irq_resend(desc, irq);
309 * enable_irq - enable handling of an irq
310 * @irq: Interrupt to enable
312 * Undoes the effect of one call to disable_irq(). If this
313 * matches the last disable, processing of interrupts on this
314 * IRQ line is re-enabled.
316 * This function may be called from IRQ context only when
317 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
319 void enable_irq(unsigned int irq)
321 struct irq_desc *desc = irq_to_desc(irq);
328 raw_spin_lock_irqsave(&desc->lock, flags);
329 __enable_irq(desc, irq, false);
330 raw_spin_unlock_irqrestore(&desc->lock, flags);
331 chip_bus_sync_unlock(desc);
333 EXPORT_SYMBOL(enable_irq);
335 static int set_irq_wake_real(unsigned int irq, unsigned int on)
337 struct irq_desc *desc = irq_to_desc(irq);
340 if (desc->irq_data.chip->irq_set_wake)
341 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
347 * set_irq_wake - control irq power management wakeup
348 * @irq: interrupt to control
349 * @on: enable/disable power management wakeup
351 * Enable/disable power management wakeup mode, which is
352 * disabled by default. Enables and disables must match,
353 * just as they match for non-wakeup mode support.
355 * Wakeup mode lets this IRQ wake the system from sleep
356 * states like "suspend to RAM".
358 int set_irq_wake(unsigned int irq, unsigned int on)
360 struct irq_desc *desc = irq_to_desc(irq);
364 /* wakeup-capable irqs can be shared between drivers that
365 * don't need to have the same sleep mode behaviors.
367 raw_spin_lock_irqsave(&desc->lock, flags);
369 if (desc->wake_depth++ == 0) {
370 ret = set_irq_wake_real(irq, on);
372 desc->wake_depth = 0;
374 desc->status |= IRQ_WAKEUP;
377 if (desc->wake_depth == 0) {
378 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
379 } else if (--desc->wake_depth == 0) {
380 ret = set_irq_wake_real(irq, on);
382 desc->wake_depth = 1;
384 desc->status &= ~IRQ_WAKEUP;
388 raw_spin_unlock_irqrestore(&desc->lock, flags);
391 EXPORT_SYMBOL(set_irq_wake);
394 * Internal function that tells the architecture code whether a
395 * particular irq has been exclusively allocated or is available
398 int can_request_irq(unsigned int irq, unsigned long irqflags)
400 struct irq_desc *desc = irq_to_desc(irq);
401 struct irqaction *action;
407 if (desc->status & IRQ_NOREQUEST)
410 raw_spin_lock_irqsave(&desc->lock, flags);
411 action = desc->action;
413 if (irqflags & action->flags & IRQF_SHARED)
416 raw_spin_unlock_irqrestore(&desc->lock, flags);
421 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
424 * If the architecture still has not overriden
425 * the flow handler then zap the default. This
426 * should catch incorrect flow-type setting.
428 if (desc->handle_irq == &handle_bad_irq)
429 desc->handle_irq = NULL;
432 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
436 struct irq_chip *chip = desc->irq_data.chip;
438 if (!chip || !chip->irq_set_type) {
440 * IRQF_TRIGGER_* but the PIC does not support multiple
443 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
444 chip ? (chip->name ? : "unknown") : "unknown");
448 /* caller masked out all except trigger mode flags */
449 ret = chip->irq_set_type(&desc->irq_data, flags);
452 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
453 flags, irq, chip->irq_set_type);
455 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
457 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
458 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
459 desc->status |= flags;
461 if (chip != desc->irq_data.chip)
462 irq_chip_set_defaults(desc->irq_data.chip);
469 * Default primary interrupt handler for threaded interrupts. Is
470 * assigned as primary handler when request_threaded_irq is called
471 * with handler == NULL. Useful for oneshot interrupts.
473 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
475 return IRQ_WAKE_THREAD;
479 * Primary handler for nested threaded interrupts. Should never be
482 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
484 WARN(1, "Primary handler called for nested irq %d\n", irq);
488 static int irq_wait_for_interrupt(struct irqaction *action)
490 while (!kthread_should_stop()) {
491 set_current_state(TASK_INTERRUPTIBLE);
493 if (test_and_clear_bit(IRQTF_RUNTHREAD,
494 &action->thread_flags)) {
495 __set_current_state(TASK_RUNNING);
504 * Oneshot interrupts keep the irq line masked until the threaded
505 * handler finished. unmask if the interrupt has not been disabled and
508 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
512 raw_spin_lock_irq(&desc->lock);
515 * Implausible though it may be we need to protect us against
516 * the following scenario:
518 * The thread is faster done than the hard interrupt handler
519 * on the other CPU. If we unmask the irq line then the
520 * interrupt can come in again and masks the line, leaves due
521 * to IRQ_INPROGRESS and the irq line is masked forever.
523 if (unlikely(desc->status & IRQ_INPROGRESS)) {
524 raw_spin_unlock_irq(&desc->lock);
525 chip_bus_sync_unlock(desc);
530 if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
531 desc->status &= ~IRQ_MASKED;
532 desc->irq_data.chip->irq_unmask(&desc->irq_data);
534 raw_spin_unlock_irq(&desc->lock);
535 chip_bus_sync_unlock(desc);
540 * Check whether we need to change the affinity of the interrupt thread.
543 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
547 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
551 * In case we are out of memory we set IRQTF_AFFINITY again and
552 * try again next time
554 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
555 set_bit(IRQTF_AFFINITY, &action->thread_flags);
559 raw_spin_lock_irq(&desc->lock);
560 cpumask_copy(mask, desc->irq_data.affinity);
561 raw_spin_unlock_irq(&desc->lock);
563 set_cpus_allowed_ptr(current, mask);
564 free_cpumask_var(mask);
568 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
572 * Interrupt handler thread
574 static int irq_thread(void *data)
576 static struct sched_param param = {
577 .sched_priority = MAX_USER_RT_PRIO/2,
579 struct irqaction *action = data;
580 struct irq_desc *desc = irq_to_desc(action->irq);
581 int wake, oneshot = desc->status & IRQ_ONESHOT;
583 sched_setscheduler(current, SCHED_FIFO, ¶m);
584 current->irqaction = action;
586 while (!irq_wait_for_interrupt(action)) {
588 irq_thread_check_affinity(desc, action);
590 atomic_inc(&desc->threads_active);
592 raw_spin_lock_irq(&desc->lock);
593 if (unlikely(desc->status & IRQ_DISABLED)) {
595 * CHECKME: We might need a dedicated
596 * IRQ_THREAD_PENDING flag here, which
597 * retriggers the thread in check_irq_resend()
598 * but AFAICT IRQ_PENDING should be fine as it
599 * retriggers the interrupt itself --- tglx
601 desc->status |= IRQ_PENDING;
602 raw_spin_unlock_irq(&desc->lock);
604 raw_spin_unlock_irq(&desc->lock);
606 action->thread_fn(action->irq, action->dev_id);
609 irq_finalize_oneshot(action->irq, desc);
612 wake = atomic_dec_and_test(&desc->threads_active);
614 if (wake && waitqueue_active(&desc->wait_for_threads))
615 wake_up(&desc->wait_for_threads);
619 * Clear irqaction. Otherwise exit_irq_thread() would make
620 * fuzz about an active irq thread going into nirvana.
622 current->irqaction = NULL;
627 * Called from do_exit()
629 void exit_irq_thread(void)
631 struct task_struct *tsk = current;
637 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
638 tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
641 * Set the THREAD DIED flag to prevent further wakeups of the
642 * soon to be gone threaded handler.
644 set_bit(IRQTF_DIED, &tsk->irqaction->flags);
648 * Internal function to register an irqaction - typically used to
649 * allocate special interrupts that are part of the architecture.
652 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
654 struct irqaction *old, **old_ptr;
655 const char *old_name = NULL;
657 int nested, shared = 0;
663 if (desc->irq_data.chip == &no_irq_chip)
666 * Some drivers like serial.c use request_irq() heavily,
667 * so we have to be careful not to interfere with a
670 if (new->flags & IRQF_SAMPLE_RANDOM) {
672 * This function might sleep, we want to call it first,
673 * outside of the atomic block.
674 * Yes, this might clear the entropy pool if the wrong
675 * driver is attempted to be loaded, without actually
676 * installing a new handler, but is this really a problem,
677 * only the sysadmin is able to do this.
679 rand_initialize_irq(irq);
682 /* Oneshot interrupts are not allowed with shared */
683 if ((new->flags & IRQF_ONESHOT) && (new->flags & IRQF_SHARED))
687 * Check whether the interrupt nests into another interrupt
690 nested = desc->status & IRQ_NESTED_THREAD;
695 * Replace the primary handler which was provided from
696 * the driver for non nested interrupt handling by the
697 * dummy function which warns when called.
699 new->handler = irq_nested_primary_handler;
703 * Create a handler thread when a thread function is supplied
704 * and the interrupt does not nest into another interrupt
707 if (new->thread_fn && !nested) {
708 struct task_struct *t;
710 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
715 * We keep the reference to the task struct even if
716 * the thread dies to avoid that the interrupt code
717 * references an already freed task_struct.
724 * The following block of code has to be executed atomically
726 raw_spin_lock_irqsave(&desc->lock, flags);
727 old_ptr = &desc->action;
731 * Can't share interrupts unless both agree to and are
732 * the same type (level, edge, polarity). So both flag
733 * fields must have IRQF_SHARED set and the bits which
734 * set the trigger type must match.
736 if (!((old->flags & new->flags) & IRQF_SHARED) ||
737 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
738 old_name = old->name;
742 #if defined(CONFIG_IRQ_PER_CPU)
743 /* All handlers must agree on per-cpuness */
744 if ((old->flags & IRQF_PERCPU) !=
745 (new->flags & IRQF_PERCPU))
749 /* add new interrupt at end of irq queue */
751 old_ptr = &old->next;
758 irq_chip_set_defaults(desc->irq_data.chip);
760 init_waitqueue_head(&desc->wait_for_threads);
762 /* Setup the type (level, edge polarity) if configured: */
763 if (new->flags & IRQF_TRIGGER_MASK) {
764 ret = __irq_set_trigger(desc, irq,
765 new->flags & IRQF_TRIGGER_MASK);
770 compat_irq_chip_set_default_handler(desc);
771 #if defined(CONFIG_IRQ_PER_CPU)
772 if (new->flags & IRQF_PERCPU)
773 desc->status |= IRQ_PER_CPU;
776 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING | IRQ_ONESHOT |
777 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
779 if (new->flags & IRQF_ONESHOT)
780 desc->status |= IRQ_ONESHOT;
782 if (!(desc->status & IRQ_NOAUTOEN)) {
784 desc->status &= ~IRQ_DISABLED;
785 desc->irq_data.chip->irq_startup(&desc->irq_data);
787 /* Undo nested disables: */
790 /* Exclude IRQ from balancing if requested */
791 if (new->flags & IRQF_NOBALANCING)
792 desc->status |= IRQ_NO_BALANCING;
794 /* Set default affinity mask once everything is setup */
795 setup_affinity(irq, desc);
797 } else if ((new->flags & IRQF_TRIGGER_MASK)
798 && (new->flags & IRQF_TRIGGER_MASK)
799 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
800 /* hope the handler works with the actual trigger mode... */
801 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
802 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
803 (int)(new->flags & IRQF_TRIGGER_MASK));
809 /* Reset broken irq detection when installing new handler */
811 desc->irqs_unhandled = 0;
814 * Check whether we disabled the irq via the spurious handler
815 * before. Reenable it and give it another chance.
817 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
818 desc->status &= ~IRQ_SPURIOUS_DISABLED;
819 __enable_irq(desc, irq, false);
822 raw_spin_unlock_irqrestore(&desc->lock, flags);
825 * Strictly no need to wake it up, but hung_task complains
826 * when no hard interrupt wakes the thread up.
829 wake_up_process(new->thread);
831 register_irq_proc(irq, desc);
833 register_handler_proc(irq, new);
838 #ifdef CONFIG_DEBUG_SHIRQ
839 if (!(new->flags & IRQF_PROBE_SHARED)) {
840 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
842 printk(KERN_ERR "current handler: %s\n", old_name);
849 raw_spin_unlock_irqrestore(&desc->lock, flags);
851 struct task_struct *t = new->thread;
854 if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
862 * setup_irq - setup an interrupt
863 * @irq: Interrupt line to setup
864 * @act: irqaction for the interrupt
866 * Used to statically setup interrupts in the early boot process.
868 int setup_irq(unsigned int irq, struct irqaction *act)
870 struct irq_desc *desc = irq_to_desc(irq);
872 return __setup_irq(irq, desc, act);
874 EXPORT_SYMBOL_GPL(setup_irq);
877 * Internal function to unregister an irqaction - used to free
878 * regular and special interrupts that are part of the architecture.
880 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
882 struct irq_desc *desc = irq_to_desc(irq);
883 struct irqaction *action, **action_ptr;
886 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
891 raw_spin_lock_irqsave(&desc->lock, flags);
894 * There can be multiple actions per IRQ descriptor, find the right
895 * one based on the dev_id:
897 action_ptr = &desc->action;
899 action = *action_ptr;
902 WARN(1, "Trying to free already-free IRQ %d\n", irq);
903 raw_spin_unlock_irqrestore(&desc->lock, flags);
908 if (action->dev_id == dev_id)
910 action_ptr = &action->next;
913 /* Found it - now remove it from the list of entries: */
914 *action_ptr = action->next;
916 /* Currently used only by UML, might disappear one day: */
917 #ifdef CONFIG_IRQ_RELEASE_METHOD
918 if (desc->irq_data.chip->release)
919 desc->irq_data.chip->release(irq, dev_id);
922 /* If this was the last handler, shut down the IRQ line: */
924 desc->status |= IRQ_DISABLED;
925 if (desc->irq_data.chip->irq_shutdown)
926 desc->irq_data.chip->irq_shutdown(&desc->irq_data);
928 desc->irq_data.chip->irq_disable(&desc->irq_data);
932 /* make sure affinity_hint is cleaned up */
933 if (WARN_ON_ONCE(desc->affinity_hint))
934 desc->affinity_hint = NULL;
937 raw_spin_unlock_irqrestore(&desc->lock, flags);
939 unregister_handler_proc(irq, action);
941 /* Make sure it's not being used on another CPU: */
942 synchronize_irq(irq);
944 #ifdef CONFIG_DEBUG_SHIRQ
946 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
947 * event to happen even now it's being freed, so let's make sure that
948 * is so by doing an extra call to the handler ....
950 * ( We do this after actually deregistering it, to make sure that a
951 * 'real' IRQ doesn't run in * parallel with our fake. )
953 if (action->flags & IRQF_SHARED) {
954 local_irq_save(flags);
955 action->handler(irq, dev_id);
956 local_irq_restore(flags);
960 if (action->thread) {
961 if (!test_bit(IRQTF_DIED, &action->thread_flags))
962 kthread_stop(action->thread);
963 put_task_struct(action->thread);
970 * remove_irq - free an interrupt
971 * @irq: Interrupt line to free
972 * @act: irqaction for the interrupt
974 * Used to remove interrupts statically setup by the early boot process.
976 void remove_irq(unsigned int irq, struct irqaction *act)
978 __free_irq(irq, act->dev_id);
980 EXPORT_SYMBOL_GPL(remove_irq);
983 * free_irq - free an interrupt allocated with request_irq
984 * @irq: Interrupt line to free
985 * @dev_id: Device identity to free
987 * Remove an interrupt handler. The handler is removed and if the
988 * interrupt line is no longer in use by any driver it is disabled.
989 * On a shared IRQ the caller must ensure the interrupt is disabled
990 * on the card it drives before calling this function. The function
991 * does not return until any executing interrupts for this IRQ
994 * This function must not be called from interrupt context.
996 void free_irq(unsigned int irq, void *dev_id)
998 struct irq_desc *desc = irq_to_desc(irq);
1003 chip_bus_lock(desc);
1004 kfree(__free_irq(irq, dev_id));
1005 chip_bus_sync_unlock(desc);
1007 EXPORT_SYMBOL(free_irq);
1010 * request_threaded_irq - allocate an interrupt line
1011 * @irq: Interrupt line to allocate
1012 * @handler: Function to be called when the IRQ occurs.
1013 * Primary handler for threaded interrupts
1014 * If NULL and thread_fn != NULL the default
1015 * primary handler is installed
1016 * @thread_fn: Function called from the irq handler thread
1017 * If NULL, no irq thread is created
1018 * @irqflags: Interrupt type flags
1019 * @devname: An ascii name for the claiming device
1020 * @dev_id: A cookie passed back to the handler function
1022 * This call allocates interrupt resources and enables the
1023 * interrupt line and IRQ handling. From the point this
1024 * call is made your handler function may be invoked. Since
1025 * your handler function must clear any interrupt the board
1026 * raises, you must take care both to initialise your hardware
1027 * and to set up the interrupt handler in the right order.
1029 * If you want to set up a threaded irq handler for your device
1030 * then you need to supply @handler and @thread_fn. @handler ist
1031 * still called in hard interrupt context and has to check
1032 * whether the interrupt originates from the device. If yes it
1033 * needs to disable the interrupt on the device and return
1034 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1035 * @thread_fn. This split handler design is necessary to support
1036 * shared interrupts.
1038 * Dev_id must be globally unique. Normally the address of the
1039 * device data structure is used as the cookie. Since the handler
1040 * receives this value it makes sense to use it.
1042 * If your interrupt is shared you must pass a non NULL dev_id
1043 * as this is required when freeing the interrupt.
1047 * IRQF_SHARED Interrupt is shared
1048 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1049 * IRQF_TRIGGER_* Specify active edge(s) or level
1052 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1053 irq_handler_t thread_fn, unsigned long irqflags,
1054 const char *devname, void *dev_id)
1056 struct irqaction *action;
1057 struct irq_desc *desc;
1061 * Sanity-check: shared interrupts must pass in a real dev-ID,
1062 * otherwise we'll have trouble later trying to figure out
1063 * which interrupt is which (messes up the interrupt freeing
1066 if ((irqflags & IRQF_SHARED) && !dev_id)
1069 desc = irq_to_desc(irq);
1073 if (desc->status & IRQ_NOREQUEST)
1079 handler = irq_default_primary_handler;
1082 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1086 action->handler = handler;
1087 action->thread_fn = thread_fn;
1088 action->flags = irqflags;
1089 action->name = devname;
1090 action->dev_id = dev_id;
1092 chip_bus_lock(desc);
1093 retval = __setup_irq(irq, desc, action);
1094 chip_bus_sync_unlock(desc);
1099 #ifdef CONFIG_DEBUG_SHIRQ
1100 if (!retval && (irqflags & IRQF_SHARED)) {
1102 * It's a shared IRQ -- the driver ought to be prepared for it
1103 * to happen immediately, so let's make sure....
1104 * We disable the irq to make sure that a 'real' IRQ doesn't
1105 * run in parallel with our fake.
1107 unsigned long flags;
1110 local_irq_save(flags);
1112 handler(irq, dev_id);
1114 local_irq_restore(flags);
1120 EXPORT_SYMBOL(request_threaded_irq);
1123 * request_any_context_irq - allocate an interrupt line
1124 * @irq: Interrupt line to allocate
1125 * @handler: Function to be called when the IRQ occurs.
1126 * Threaded handler for threaded interrupts.
1127 * @flags: Interrupt type flags
1128 * @name: An ascii name for the claiming device
1129 * @dev_id: A cookie passed back to the handler function
1131 * This call allocates interrupt resources and enables the
1132 * interrupt line and IRQ handling. It selects either a
1133 * hardirq or threaded handling method depending on the
1136 * On failure, it returns a negative value. On success,
1137 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1139 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1140 unsigned long flags, const char *name, void *dev_id)
1142 struct irq_desc *desc = irq_to_desc(irq);
1148 if (desc->status & IRQ_NESTED_THREAD) {
1149 ret = request_threaded_irq(irq, NULL, handler,
1150 flags, name, dev_id);
1151 return !ret ? IRQC_IS_NESTED : ret;
1154 ret = request_irq(irq, handler, flags, name, dev_id);
1155 return !ret ? IRQC_IS_HARDIRQ : ret;
1157 EXPORT_SYMBOL_GPL(request_any_context_irq);