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"
20 #ifdef CONFIG_IRQ_FORCED_THREADING
21 __read_mostly bool force_irqthreads;
23 static int __init setup_forced_irqthreads(char *arg)
25 force_irqthreads = true;
28 early_param("threadirqs", setup_forced_irqthreads);
32 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
33 * @irq: interrupt number to wait for
35 * This function waits for any pending IRQ handlers for this interrupt
36 * to complete before returning. If you use this function while
37 * holding a resource the IRQ handler may need you will deadlock.
39 * This function may be called - with care - from IRQ context.
41 void synchronize_irq(unsigned int irq)
43 struct irq_desc *desc = irq_to_desc(irq);
53 * Wait until we're out of the critical section. This might
54 * give the wrong answer due to the lack of memory barriers.
56 while (irqd_irq_inprogress(&desc->irq_data))
59 /* Ok, that indicated we're done: double-check carefully. */
60 raw_spin_lock_irqsave(&desc->lock, flags);
61 inprogress = irqd_irq_inprogress(&desc->irq_data);
62 raw_spin_unlock_irqrestore(&desc->lock, flags);
64 /* Oops, that failed? */
68 * We made sure that no hardirq handler is running. Now verify
69 * that no threaded handlers are active.
71 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
73 EXPORT_SYMBOL(synchronize_irq);
76 cpumask_var_t irq_default_affinity;
79 * irq_can_set_affinity - Check if the affinity of a given irq can be set
80 * @irq: Interrupt to check
83 int irq_can_set_affinity(unsigned int irq)
85 struct irq_desc *desc = irq_to_desc(irq);
87 if (!desc || !irqd_can_balance(&desc->irq_data) ||
88 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
95 * irq_set_thread_affinity - Notify irq threads to adjust affinity
96 * @desc: irq descriptor which has affitnity changed
98 * We just set IRQTF_AFFINITY and delegate the affinity setting
99 * to the interrupt thread itself. We can not call
100 * set_cpus_allowed_ptr() here as we hold desc->lock and this
101 * code can be called from hard interrupt context.
103 void irq_set_thread_affinity(struct irq_desc *desc)
105 struct irqaction *action = desc->action;
109 set_bit(IRQTF_AFFINITY, &action->thread_flags);
110 action = action->next;
114 #ifdef CONFIG_GENERIC_PENDING_IRQ
115 static inline bool irq_can_move_pcntxt(struct irq_data *data)
117 return irqd_can_move_in_process_context(data);
119 static inline bool irq_move_pending(struct irq_data *data)
121 return irqd_is_setaffinity_pending(data);
124 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
126 cpumask_copy(desc->pending_mask, mask);
129 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
131 cpumask_copy(mask, desc->pending_mask);
134 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
135 static inline bool irq_move_pending(struct irq_data *data) { return false; }
137 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
139 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
142 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
144 struct irq_chip *chip = irq_data_get_irq_chip(data);
145 struct irq_desc *desc = irq_data_to_desc(data);
148 if (!chip || !chip->irq_set_affinity)
151 if (irq_can_move_pcntxt(data)) {
152 ret = chip->irq_set_affinity(data, mask, false);
154 case IRQ_SET_MASK_OK:
155 cpumask_copy(data->affinity, mask);
156 case IRQ_SET_MASK_OK_NOCOPY:
157 irq_set_thread_affinity(desc);
161 irqd_set_move_pending(data);
162 irq_copy_pending(desc, mask);
165 if (desc->affinity_notify) {
166 kref_get(&desc->affinity_notify->kref);
167 schedule_work(&desc->affinity_notify->work);
169 irqd_set(data, IRQD_AFFINITY_SET);
175 * irq_set_affinity - Set the irq affinity of a given irq
176 * @irq: Interrupt to set affinity
180 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
182 struct irq_desc *desc = irq_to_desc(irq);
189 raw_spin_lock_irqsave(&desc->lock, flags);
190 ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
191 raw_spin_unlock_irqrestore(&desc->lock, flags);
195 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
198 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
202 desc->affinity_hint = m;
203 irq_put_desc_unlock(desc, flags);
206 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
208 static void irq_affinity_notify(struct work_struct *work)
210 struct irq_affinity_notify *notify =
211 container_of(work, struct irq_affinity_notify, work);
212 struct irq_desc *desc = irq_to_desc(notify->irq);
213 cpumask_var_t cpumask;
216 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
219 raw_spin_lock_irqsave(&desc->lock, flags);
220 if (irq_move_pending(&desc->irq_data))
221 irq_get_pending(cpumask, desc);
223 cpumask_copy(cpumask, desc->irq_data.affinity);
224 raw_spin_unlock_irqrestore(&desc->lock, flags);
226 notify->notify(notify, cpumask);
228 free_cpumask_var(cpumask);
230 kref_put(¬ify->kref, notify->release);
234 * irq_set_affinity_notifier - control notification of IRQ affinity changes
235 * @irq: Interrupt for which to enable/disable notification
236 * @notify: Context for notification, or %NULL to disable
237 * notification. Function pointers must be initialised;
238 * the other fields will be initialised by this function.
240 * Must be called in process context. Notification may only be enabled
241 * after the IRQ is allocated and must be disabled before the IRQ is
242 * freed using free_irq().
245 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
247 struct irq_desc *desc = irq_to_desc(irq);
248 struct irq_affinity_notify *old_notify;
251 /* The release function is promised process context */
257 /* Complete initialisation of *notify */
260 kref_init(¬ify->kref);
261 INIT_WORK(¬ify->work, irq_affinity_notify);
264 raw_spin_lock_irqsave(&desc->lock, flags);
265 old_notify = desc->affinity_notify;
266 desc->affinity_notify = notify;
267 raw_spin_unlock_irqrestore(&desc->lock, flags);
270 kref_put(&old_notify->kref, old_notify->release);
274 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
276 #ifndef CONFIG_AUTO_IRQ_AFFINITY
278 * Generic version of the affinity autoselector.
281 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
283 struct irq_chip *chip = irq_desc_get_chip(desc);
284 struct cpumask *set = irq_default_affinity;
287 /* Excludes PER_CPU and NO_BALANCE interrupts */
288 if (!irq_can_set_affinity(irq))
292 * Preserve an userspace affinity setup, but make sure that
293 * one of the targets is online.
295 if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
296 if (cpumask_intersects(desc->irq_data.affinity,
298 set = desc->irq_data.affinity;
300 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
303 cpumask_and(mask, cpu_online_mask, set);
304 ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
306 case IRQ_SET_MASK_OK:
307 cpumask_copy(desc->irq_data.affinity, mask);
308 case IRQ_SET_MASK_OK_NOCOPY:
309 irq_set_thread_affinity(desc);
315 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
317 return irq_select_affinity(irq);
322 * Called when affinity is set via /proc/irq
324 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
326 struct irq_desc *desc = irq_to_desc(irq);
330 raw_spin_lock_irqsave(&desc->lock, flags);
331 ret = setup_affinity(irq, desc, mask);
332 raw_spin_unlock_irqrestore(&desc->lock, flags);
338 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
344 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
347 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
349 desc->istate |= IRQS_SUSPENDED;
356 static int __disable_irq_nosync(unsigned int irq)
359 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
363 __disable_irq(desc, irq, false);
364 irq_put_desc_busunlock(desc, flags);
369 * disable_irq_nosync - disable an irq without waiting
370 * @irq: Interrupt to disable
372 * Disable the selected interrupt line. Disables and Enables are
374 * Unlike disable_irq(), this function does not ensure existing
375 * instances of the IRQ handler have completed before returning.
377 * This function may be called from IRQ context.
379 void disable_irq_nosync(unsigned int irq)
381 __disable_irq_nosync(irq);
383 EXPORT_SYMBOL(disable_irq_nosync);
386 * disable_irq - disable an irq and wait for completion
387 * @irq: Interrupt to disable
389 * Disable the selected interrupt line. Enables and Disables are
391 * This function waits for any pending IRQ handlers for this interrupt
392 * to complete before returning. If you use this function while
393 * holding a resource the IRQ handler may need you will deadlock.
395 * This function may be called - with care - from IRQ context.
397 void disable_irq(unsigned int irq)
399 if (!__disable_irq_nosync(irq))
400 synchronize_irq(irq);
402 EXPORT_SYMBOL(disable_irq);
404 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
407 if (!(desc->istate & IRQS_SUSPENDED)) {
410 if (!(desc->action->flags & IRQF_FORCE_RESUME))
412 /* Pretend that it got disabled ! */
415 desc->istate &= ~IRQS_SUSPENDED;
418 switch (desc->depth) {
421 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
424 if (desc->istate & IRQS_SUSPENDED)
426 /* Prevent probing on this irq: */
427 irq_settings_set_noprobe(desc);
429 check_irq_resend(desc, irq);
438 * enable_irq - enable handling of an irq
439 * @irq: Interrupt to enable
441 * Undoes the effect of one call to disable_irq(). If this
442 * matches the last disable, processing of interrupts on this
443 * IRQ line is re-enabled.
445 * This function may be called from IRQ context only when
446 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
448 void enable_irq(unsigned int irq)
451 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
455 if (WARN(!desc->irq_data.chip,
456 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
459 __enable_irq(desc, irq, false);
461 irq_put_desc_busunlock(desc, flags);
463 EXPORT_SYMBOL(enable_irq);
465 static int set_irq_wake_real(unsigned int irq, unsigned int on)
467 struct irq_desc *desc = irq_to_desc(irq);
470 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
473 if (desc->irq_data.chip->irq_set_wake)
474 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
480 * irq_set_irq_wake - control irq power management wakeup
481 * @irq: interrupt to control
482 * @on: enable/disable power management wakeup
484 * Enable/disable power management wakeup mode, which is
485 * disabled by default. Enables and disables must match,
486 * just as they match for non-wakeup mode support.
488 * Wakeup mode lets this IRQ wake the system from sleep
489 * states like "suspend to RAM".
491 int irq_set_irq_wake(unsigned int irq, unsigned int on)
494 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
500 /* wakeup-capable irqs can be shared between drivers that
501 * don't need to have the same sleep mode behaviors.
504 if (desc->wake_depth++ == 0) {
505 ret = set_irq_wake_real(irq, on);
507 desc->wake_depth = 0;
509 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
512 if (desc->wake_depth == 0) {
513 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
514 } else if (--desc->wake_depth == 0) {
515 ret = set_irq_wake_real(irq, on);
517 desc->wake_depth = 1;
519 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
522 irq_put_desc_busunlock(desc, flags);
525 EXPORT_SYMBOL(irq_set_irq_wake);
528 * Internal function that tells the architecture code whether a
529 * particular irq has been exclusively allocated or is available
532 int can_request_irq(unsigned int irq, unsigned long irqflags)
535 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
541 if (irq_settings_can_request(desc)) {
543 if (irqflags & desc->action->flags & IRQF_SHARED)
546 irq_put_desc_unlock(desc, flags);
550 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
553 struct irq_chip *chip = desc->irq_data.chip;
556 if (!chip || !chip->irq_set_type) {
558 * IRQF_TRIGGER_* but the PIC does not support multiple
561 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
562 chip ? (chip->name ? : "unknown") : "unknown");
566 flags &= IRQ_TYPE_SENSE_MASK;
568 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
569 if (!irqd_irq_masked(&desc->irq_data))
571 if (!irqd_irq_disabled(&desc->irq_data))
575 /* caller masked out all except trigger mode flags */
576 ret = chip->irq_set_type(&desc->irq_data, flags);
579 case IRQ_SET_MASK_OK:
580 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
581 irqd_set(&desc->irq_data, flags);
583 case IRQ_SET_MASK_OK_NOCOPY:
584 flags = irqd_get_trigger_type(&desc->irq_data);
585 irq_settings_set_trigger_mask(desc, flags);
586 irqd_clear(&desc->irq_data, IRQD_LEVEL);
587 irq_settings_clr_level(desc);
588 if (flags & IRQ_TYPE_LEVEL_MASK) {
589 irq_settings_set_level(desc);
590 irqd_set(&desc->irq_data, IRQD_LEVEL);
596 pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
597 flags, irq, chip->irq_set_type);
605 * Default primary interrupt handler for threaded interrupts. Is
606 * assigned as primary handler when request_threaded_irq is called
607 * with handler == NULL. Useful for oneshot interrupts.
609 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
611 return IRQ_WAKE_THREAD;
615 * Primary handler for nested threaded interrupts. Should never be
618 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
620 WARN(1, "Primary handler called for nested irq %d\n", irq);
624 static int irq_wait_for_interrupt(struct irqaction *action)
626 set_current_state(TASK_INTERRUPTIBLE);
628 while (!kthread_should_stop()) {
630 if (test_and_clear_bit(IRQTF_RUNTHREAD,
631 &action->thread_flags)) {
632 __set_current_state(TASK_RUNNING);
636 set_current_state(TASK_INTERRUPTIBLE);
638 __set_current_state(TASK_RUNNING);
643 * Oneshot interrupts keep the irq line masked until the threaded
644 * handler finished. unmask if the interrupt has not been disabled and
647 static void irq_finalize_oneshot(struct irq_desc *desc,
648 struct irqaction *action, bool force)
650 if (!(desc->istate & IRQS_ONESHOT))
654 raw_spin_lock_irq(&desc->lock);
657 * Implausible though it may be we need to protect us against
658 * the following scenario:
660 * The thread is faster done than the hard interrupt handler
661 * on the other CPU. If we unmask the irq line then the
662 * interrupt can come in again and masks the line, leaves due
663 * to IRQS_INPROGRESS and the irq line is masked forever.
665 * This also serializes the state of shared oneshot handlers
666 * versus "desc->threads_onehsot |= action->thread_mask;" in
667 * irq_wake_thread(). See the comment there which explains the
670 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
671 raw_spin_unlock_irq(&desc->lock);
672 chip_bus_sync_unlock(desc);
678 * Now check again, whether the thread should run. Otherwise
679 * we would clear the threads_oneshot bit of this thread which
682 if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
685 desc->threads_oneshot &= ~action->thread_mask;
687 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
688 irqd_irq_masked(&desc->irq_data))
692 raw_spin_unlock_irq(&desc->lock);
693 chip_bus_sync_unlock(desc);
698 * Check whether we need to chasnge the affinity of the interrupt thread.
701 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
705 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
709 * In case we are out of memory we set IRQTF_AFFINITY again and
710 * try again next time
712 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
713 set_bit(IRQTF_AFFINITY, &action->thread_flags);
717 raw_spin_lock_irq(&desc->lock);
718 cpumask_copy(mask, desc->irq_data.affinity);
719 raw_spin_unlock_irq(&desc->lock);
721 set_cpus_allowed_ptr(current, mask);
722 free_cpumask_var(mask);
726 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
730 * Interrupts which are not explicitely requested as threaded
731 * interrupts rely on the implicit bh/preempt disable of the hard irq
732 * context. So we need to disable bh here to avoid deadlocks and other
736 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
741 ret = action->thread_fn(action->irq, action->dev_id);
742 irq_finalize_oneshot(desc, action, false);
748 * Interrupts explicitely requested as threaded interupts want to be
749 * preemtible - many of them need to sleep and wait for slow busses to
752 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
753 struct irqaction *action)
757 ret = action->thread_fn(action->irq, action->dev_id);
758 irq_finalize_oneshot(desc, action, false);
762 static void wake_threads_waitq(struct irq_desc *desc)
764 if (atomic_dec_and_test(&desc->threads_active) &&
765 waitqueue_active(&desc->wait_for_threads))
766 wake_up(&desc->wait_for_threads);
770 * Interrupt handler thread
772 static int irq_thread(void *data)
774 static const struct sched_param param = {
775 .sched_priority = MAX_USER_RT_PRIO/2,
777 struct irqaction *action = data;
778 struct irq_desc *desc = irq_to_desc(action->irq);
779 irqreturn_t (*handler_fn)(struct irq_desc *desc,
780 struct irqaction *action);
782 if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
783 &action->thread_flags))
784 handler_fn = irq_forced_thread_fn;
786 handler_fn = irq_thread_fn;
788 sched_setscheduler(current, SCHED_FIFO, ¶m);
789 current->irq_thread = 1;
791 while (!irq_wait_for_interrupt(action)) {
792 irqreturn_t action_ret;
794 irq_thread_check_affinity(desc, action);
796 action_ret = handler_fn(desc, action);
798 note_interrupt(action->irq, desc, action_ret);
800 wake_threads_waitq(desc);
804 * This is the regular exit path. __free_irq() is stopping the
805 * thread via kthread_stop() after calling
806 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
807 * oneshot mask bit can be set. We cannot verify that as we
808 * cannot touch the oneshot mask at this point anymore as
809 * __setup_irq() might have given out currents thread_mask
812 * Clear irq_thread. Otherwise exit_irq_thread() would make
813 * fuzz about an active irq thread going into nirvana.
815 current->irq_thread = 0;
820 * Called from do_exit()
822 void exit_irq_thread(void)
824 struct task_struct *tsk = current;
825 struct irq_desc *desc;
826 struct irqaction *action;
828 if (!tsk->irq_thread)
831 action = kthread_data(tsk);
834 "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
835 tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
837 desc = irq_to_desc(action->irq);
840 * If IRQTF_RUNTHREAD is set, we need to decrement
841 * desc->threads_active and wake possible waiters.
843 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
844 wake_threads_waitq(desc);
846 /* Prevent a stale desc->threads_oneshot */
847 irq_finalize_oneshot(desc, action, true);
850 static void irq_setup_forced_threading(struct irqaction *new)
852 if (!force_irqthreads)
854 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
857 new->flags |= IRQF_ONESHOT;
859 if (!new->thread_fn) {
860 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
861 new->thread_fn = new->handler;
862 new->handler = irq_default_primary_handler;
867 * Internal function to register an irqaction - typically used to
868 * allocate special interrupts that are part of the architecture.
871 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
873 struct irqaction *old, **old_ptr;
874 const char *old_name = NULL;
875 unsigned long flags, thread_mask = 0;
876 int ret, nested, shared = 0;
882 if (desc->irq_data.chip == &no_irq_chip)
884 if (!try_module_get(desc->owner))
887 * Some drivers like serial.c use request_irq() heavily,
888 * so we have to be careful not to interfere with a
891 if (new->flags & IRQF_SAMPLE_RANDOM) {
893 * This function might sleep, we want to call it first,
894 * outside of the atomic block.
895 * Yes, this might clear the entropy pool if the wrong
896 * driver is attempted to be loaded, without actually
897 * installing a new handler, but is this really a problem,
898 * only the sysadmin is able to do this.
900 rand_initialize_irq(irq);
904 * Check whether the interrupt nests into another interrupt
907 nested = irq_settings_is_nested_thread(desc);
909 if (!new->thread_fn) {
914 * Replace the primary handler which was provided from
915 * the driver for non nested interrupt handling by the
916 * dummy function which warns when called.
918 new->handler = irq_nested_primary_handler;
920 if (irq_settings_can_thread(desc))
921 irq_setup_forced_threading(new);
925 * Create a handler thread when a thread function is supplied
926 * and the interrupt does not nest into another interrupt
929 if (new->thread_fn && !nested) {
930 struct task_struct *t;
932 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
939 * We keep the reference to the task struct even if
940 * the thread dies to avoid that the interrupt code
941 * references an already freed task_struct.
947 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
953 * The following block of code has to be executed atomically
955 raw_spin_lock_irqsave(&desc->lock, flags);
956 old_ptr = &desc->action;
960 * Can't share interrupts unless both agree to and are
961 * the same type (level, edge, polarity). So both flag
962 * fields must have IRQF_SHARED set and the bits which
963 * set the trigger type must match. Also all must
966 if (!((old->flags & new->flags) & IRQF_SHARED) ||
967 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
968 ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
969 old_name = old->name;
973 /* All handlers must agree on per-cpuness */
974 if ((old->flags & IRQF_PERCPU) !=
975 (new->flags & IRQF_PERCPU))
978 /* add new interrupt at end of irq queue */
981 * Or all existing action->thread_mask bits,
982 * so we can find the next zero bit for this
985 thread_mask |= old->thread_mask;
986 old_ptr = &old->next;
993 * Setup the thread mask for this irqaction for ONESHOT. For
994 * !ONESHOT irqs the thread mask is 0 so we can avoid a
995 * conditional in irq_wake_thread().
997 if (new->flags & IRQF_ONESHOT) {
999 * Unlikely to have 32 resp 64 irqs sharing one line,
1002 if (thread_mask == ~0UL) {
1007 * The thread_mask for the action is or'ed to
1008 * desc->thread_active to indicate that the
1009 * IRQF_ONESHOT thread handler has been woken, but not
1010 * yet finished. The bit is cleared when a thread
1011 * completes. When all threads of a shared interrupt
1012 * line have completed desc->threads_active becomes
1013 * zero and the interrupt line is unmasked. See
1014 * handle.c:irq_wake_thread() for further information.
1016 * If no thread is woken by primary (hard irq context)
1017 * interrupt handlers, then desc->threads_active is
1018 * also checked for zero to unmask the irq line in the
1019 * affected hard irq flow handlers
1020 * (handle_[fasteoi|level]_irq).
1022 * The new action gets the first zero bit of
1023 * thread_mask assigned. See the loop above which or's
1024 * all existing action->thread_mask bits.
1026 new->thread_mask = 1 << ffz(thread_mask);
1030 init_waitqueue_head(&desc->wait_for_threads);
1032 /* Setup the type (level, edge polarity) if configured: */
1033 if (new->flags & IRQF_TRIGGER_MASK) {
1034 ret = __irq_set_trigger(desc, irq,
1035 new->flags & IRQF_TRIGGER_MASK);
1041 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1042 IRQS_ONESHOT | IRQS_WAITING);
1043 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1045 if (new->flags & IRQF_PERCPU) {
1046 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1047 irq_settings_set_per_cpu(desc);
1050 if (new->flags & IRQF_ONESHOT)
1051 desc->istate |= IRQS_ONESHOT;
1053 if (irq_settings_can_autoenable(desc))
1054 irq_startup(desc, true);
1056 /* Undo nested disables: */
1059 /* Exclude IRQ from balancing if requested */
1060 if (new->flags & IRQF_NOBALANCING) {
1061 irq_settings_set_no_balancing(desc);
1062 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1065 /* Set default affinity mask once everything is setup */
1066 setup_affinity(irq, desc, mask);
1068 } else if (new->flags & IRQF_TRIGGER_MASK) {
1069 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1070 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1073 /* hope the handler works with current trigger mode */
1074 pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
1081 /* Reset broken irq detection when installing new handler */
1082 desc->irq_count = 0;
1083 desc->irqs_unhandled = 0;
1086 * Check whether we disabled the irq via the spurious handler
1087 * before. Reenable it and give it another chance.
1089 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1090 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1091 __enable_irq(desc, irq, false);
1094 raw_spin_unlock_irqrestore(&desc->lock, flags);
1097 * Strictly no need to wake it up, but hung_task complains
1098 * when no hard interrupt wakes the thread up.
1101 wake_up_process(new->thread);
1103 register_irq_proc(irq, desc);
1105 register_handler_proc(irq, new);
1106 free_cpumask_var(mask);
1111 #ifdef CONFIG_DEBUG_SHIRQ
1112 if (!(new->flags & IRQF_PROBE_SHARED)) {
1113 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
1115 printk(KERN_ERR "current handler: %s\n", old_name);
1122 raw_spin_unlock_irqrestore(&desc->lock, flags);
1123 free_cpumask_var(mask);
1127 struct task_struct *t = new->thread;
1134 module_put(desc->owner);
1139 * setup_irq - setup an interrupt
1140 * @irq: Interrupt line to setup
1141 * @act: irqaction for the interrupt
1143 * Used to statically setup interrupts in the early boot process.
1145 int setup_irq(unsigned int irq, struct irqaction *act)
1148 struct irq_desc *desc = irq_to_desc(irq);
1150 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1152 chip_bus_lock(desc);
1153 retval = __setup_irq(irq, desc, act);
1154 chip_bus_sync_unlock(desc);
1158 EXPORT_SYMBOL_GPL(setup_irq);
1161 * Internal function to unregister an irqaction - used to free
1162 * regular and special interrupts that are part of the architecture.
1164 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1166 struct irq_desc *desc = irq_to_desc(irq);
1167 struct irqaction *action, **action_ptr;
1168 unsigned long flags;
1170 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1175 raw_spin_lock_irqsave(&desc->lock, flags);
1178 * There can be multiple actions per IRQ descriptor, find the right
1179 * one based on the dev_id:
1181 action_ptr = &desc->action;
1183 action = *action_ptr;
1186 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1187 raw_spin_unlock_irqrestore(&desc->lock, flags);
1192 if (action->dev_id == dev_id)
1194 action_ptr = &action->next;
1197 /* Found it - now remove it from the list of entries: */
1198 *action_ptr = action->next;
1200 /* Currently used only by UML, might disappear one day: */
1201 #ifdef CONFIG_IRQ_RELEASE_METHOD
1202 if (desc->irq_data.chip->release)
1203 desc->irq_data.chip->release(irq, dev_id);
1206 /* If this was the last handler, shut down the IRQ line: */
1211 /* make sure affinity_hint is cleaned up */
1212 if (WARN_ON_ONCE(desc->affinity_hint))
1213 desc->affinity_hint = NULL;
1216 raw_spin_unlock_irqrestore(&desc->lock, flags);
1218 unregister_handler_proc(irq, action);
1220 /* Make sure it's not being used on another CPU: */
1221 synchronize_irq(irq);
1223 #ifdef CONFIG_DEBUG_SHIRQ
1225 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1226 * event to happen even now it's being freed, so let's make sure that
1227 * is so by doing an extra call to the handler ....
1229 * ( We do this after actually deregistering it, to make sure that a
1230 * 'real' IRQ doesn't run in * parallel with our fake. )
1232 if (action->flags & IRQF_SHARED) {
1233 local_irq_save(flags);
1234 action->handler(irq, dev_id);
1235 local_irq_restore(flags);
1239 if (action->thread) {
1240 kthread_stop(action->thread);
1241 put_task_struct(action->thread);
1244 module_put(desc->owner);
1249 * remove_irq - free an interrupt
1250 * @irq: Interrupt line to free
1251 * @act: irqaction for the interrupt
1253 * Used to remove interrupts statically setup by the early boot process.
1255 void remove_irq(unsigned int irq, struct irqaction *act)
1257 struct irq_desc *desc = irq_to_desc(irq);
1259 if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1260 __free_irq(irq, act->dev_id);
1262 EXPORT_SYMBOL_GPL(remove_irq);
1265 * free_irq - free an interrupt allocated with request_irq
1266 * @irq: Interrupt line to free
1267 * @dev_id: Device identity to free
1269 * Remove an interrupt handler. The handler is removed and if the
1270 * interrupt line is no longer in use by any driver it is disabled.
1271 * On a shared IRQ the caller must ensure the interrupt is disabled
1272 * on the card it drives before calling this function. The function
1273 * does not return until any executing interrupts for this IRQ
1276 * This function must not be called from interrupt context.
1278 void free_irq(unsigned int irq, void *dev_id)
1280 struct irq_desc *desc = irq_to_desc(irq);
1282 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1286 if (WARN_ON(desc->affinity_notify))
1287 desc->affinity_notify = NULL;
1290 chip_bus_lock(desc);
1291 kfree(__free_irq(irq, dev_id));
1292 chip_bus_sync_unlock(desc);
1294 EXPORT_SYMBOL(free_irq);
1297 * request_threaded_irq - allocate an interrupt line
1298 * @irq: Interrupt line to allocate
1299 * @handler: Function to be called when the IRQ occurs.
1300 * Primary handler for threaded interrupts
1301 * If NULL and thread_fn != NULL the default
1302 * primary handler is installed
1303 * @thread_fn: Function called from the irq handler thread
1304 * If NULL, no irq thread is created
1305 * @irqflags: Interrupt type flags
1306 * @devname: An ascii name for the claiming device
1307 * @dev_id: A cookie passed back to the handler function
1309 * This call allocates interrupt resources and enables the
1310 * interrupt line and IRQ handling. From the point this
1311 * call is made your handler function may be invoked. Since
1312 * your handler function must clear any interrupt the board
1313 * raises, you must take care both to initialise your hardware
1314 * and to set up the interrupt handler in the right order.
1316 * If you want to set up a threaded irq handler for your device
1317 * then you need to supply @handler and @thread_fn. @handler is
1318 * still called in hard interrupt context and has to check
1319 * whether the interrupt originates from the device. If yes it
1320 * needs to disable the interrupt on the device and return
1321 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1322 * @thread_fn. This split handler design is necessary to support
1323 * shared interrupts.
1325 * Dev_id must be globally unique. Normally the address of the
1326 * device data structure is used as the cookie. Since the handler
1327 * receives this value it makes sense to use it.
1329 * If your interrupt is shared you must pass a non NULL dev_id
1330 * as this is required when freeing the interrupt.
1334 * IRQF_SHARED Interrupt is shared
1335 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1336 * IRQF_TRIGGER_* Specify active edge(s) or level
1339 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1340 irq_handler_t thread_fn, unsigned long irqflags,
1341 const char *devname, void *dev_id)
1343 struct irqaction *action;
1344 struct irq_desc *desc;
1348 * Sanity-check: shared interrupts must pass in a real dev-ID,
1349 * otherwise we'll have trouble later trying to figure out
1350 * which interrupt is which (messes up the interrupt freeing
1353 if ((irqflags & IRQF_SHARED) && !dev_id)
1356 desc = irq_to_desc(irq);
1360 if (!irq_settings_can_request(desc) ||
1361 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1367 handler = irq_default_primary_handler;
1370 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1374 action->handler = handler;
1375 action->thread_fn = thread_fn;
1376 action->flags = irqflags;
1377 action->name = devname;
1378 action->dev_id = dev_id;
1380 chip_bus_lock(desc);
1381 retval = __setup_irq(irq, desc, action);
1382 chip_bus_sync_unlock(desc);
1387 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1388 if (!retval && (irqflags & IRQF_SHARED)) {
1390 * It's a shared IRQ -- the driver ought to be prepared for it
1391 * to happen immediately, so let's make sure....
1392 * We disable the irq to make sure that a 'real' IRQ doesn't
1393 * run in parallel with our fake.
1395 unsigned long flags;
1398 local_irq_save(flags);
1400 handler(irq, dev_id);
1402 local_irq_restore(flags);
1408 EXPORT_SYMBOL(request_threaded_irq);
1411 * request_any_context_irq - allocate an interrupt line
1412 * @irq: Interrupt line to allocate
1413 * @handler: Function to be called when the IRQ occurs.
1414 * Threaded handler for threaded interrupts.
1415 * @flags: Interrupt type flags
1416 * @name: An ascii name for the claiming device
1417 * @dev_id: A cookie passed back to the handler function
1419 * This call allocates interrupt resources and enables the
1420 * interrupt line and IRQ handling. It selects either a
1421 * hardirq or threaded handling method depending on the
1424 * On failure, it returns a negative value. On success,
1425 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1427 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1428 unsigned long flags, const char *name, void *dev_id)
1430 struct irq_desc *desc = irq_to_desc(irq);
1436 if (irq_settings_is_nested_thread(desc)) {
1437 ret = request_threaded_irq(irq, NULL, handler,
1438 flags, name, dev_id);
1439 return !ret ? IRQC_IS_NESTED : ret;
1442 ret = request_irq(irq, handler, flags, name, dev_id);
1443 return !ret ? IRQC_IS_HARDIRQ : ret;
1445 EXPORT_SYMBOL_GPL(request_any_context_irq);
1447 void enable_percpu_irq(unsigned int irq, unsigned int type)
1449 unsigned int cpu = smp_processor_id();
1450 unsigned long flags;
1451 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1456 type &= IRQ_TYPE_SENSE_MASK;
1457 if (type != IRQ_TYPE_NONE) {
1460 ret = __irq_set_trigger(desc, irq, type);
1463 WARN(1, "failed to set type for IRQ%d\n", irq);
1468 irq_percpu_enable(desc, cpu);
1470 irq_put_desc_unlock(desc, flags);
1473 void disable_percpu_irq(unsigned int irq)
1475 unsigned int cpu = smp_processor_id();
1476 unsigned long flags;
1477 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1482 irq_percpu_disable(desc, cpu);
1483 irq_put_desc_unlock(desc, flags);
1487 * Internal function to unregister a percpu irqaction.
1489 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1491 struct irq_desc *desc = irq_to_desc(irq);
1492 struct irqaction *action;
1493 unsigned long flags;
1495 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1500 raw_spin_lock_irqsave(&desc->lock, flags);
1502 action = desc->action;
1503 if (!action || action->percpu_dev_id != dev_id) {
1504 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1508 if (!cpumask_empty(desc->percpu_enabled)) {
1509 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1510 irq, cpumask_first(desc->percpu_enabled));
1514 /* Found it - now remove it from the list of entries: */
1515 desc->action = NULL;
1517 raw_spin_unlock_irqrestore(&desc->lock, flags);
1519 unregister_handler_proc(irq, action);
1521 module_put(desc->owner);
1525 raw_spin_unlock_irqrestore(&desc->lock, flags);
1530 * remove_percpu_irq - free a per-cpu interrupt
1531 * @irq: Interrupt line to free
1532 * @act: irqaction for the interrupt
1534 * Used to remove interrupts statically setup by the early boot process.
1536 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1538 struct irq_desc *desc = irq_to_desc(irq);
1540 if (desc && irq_settings_is_per_cpu_devid(desc))
1541 __free_percpu_irq(irq, act->percpu_dev_id);
1545 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
1546 * @irq: Interrupt line to free
1547 * @dev_id: Device identity to free
1549 * Remove a percpu interrupt handler. The handler is removed, but
1550 * the interrupt line is not disabled. This must be done on each
1551 * CPU before calling this function. The function does not return
1552 * until any executing interrupts for this IRQ have completed.
1554 * This function must not be called from interrupt context.
1556 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1558 struct irq_desc *desc = irq_to_desc(irq);
1560 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1563 chip_bus_lock(desc);
1564 kfree(__free_percpu_irq(irq, dev_id));
1565 chip_bus_sync_unlock(desc);
1569 * setup_percpu_irq - setup a per-cpu interrupt
1570 * @irq: Interrupt line to setup
1571 * @act: irqaction for the interrupt
1573 * Used to statically setup per-cpu interrupts in the early boot process.
1575 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1577 struct irq_desc *desc = irq_to_desc(irq);
1580 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1582 chip_bus_lock(desc);
1583 retval = __setup_irq(irq, desc, act);
1584 chip_bus_sync_unlock(desc);
1590 * request_percpu_irq - allocate a percpu interrupt line
1591 * @irq: Interrupt line to allocate
1592 * @handler: Function to be called when the IRQ occurs.
1593 * @devname: An ascii name for the claiming device
1594 * @dev_id: A percpu cookie passed back to the handler function
1596 * This call allocates interrupt resources, but doesn't
1597 * automatically enable the interrupt. It has to be done on each
1598 * CPU using enable_percpu_irq().
1600 * Dev_id must be globally unique. It is a per-cpu variable, and
1601 * the handler gets called with the interrupted CPU's instance of
1604 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1605 const char *devname, void __percpu *dev_id)
1607 struct irqaction *action;
1608 struct irq_desc *desc;
1614 desc = irq_to_desc(irq);
1615 if (!desc || !irq_settings_can_request(desc) ||
1616 !irq_settings_is_per_cpu_devid(desc))
1619 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1623 action->handler = handler;
1624 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1625 action->name = devname;
1626 action->percpu_dev_id = dev_id;
1628 chip_bus_lock(desc);
1629 retval = __setup_irq(irq, desc, action);
1630 chip_bus_sync_unlock(desc);