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 #define pr_fmt(fmt) "genirq: " fmt
12 #include <linux/irq.h>
13 #include <linux/kthread.h>
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/interrupt.h>
17 #include <linux/slab.h>
18 #include <linux/sched.h>
19 #include <linux/sched/rt.h>
20 #include <linux/task_work.h>
22 #include "internals.h"
24 #ifdef CONFIG_IRQ_FORCED_THREADING
25 __read_mostly bool force_irqthreads;
27 static int __init setup_forced_irqthreads(char *arg)
29 force_irqthreads = true;
32 early_param("threadirqs", setup_forced_irqthreads);
35 static void __synchronize_hardirq(struct irq_desc *desc)
43 * Wait until we're out of the critical section. This might
44 * give the wrong answer due to the lack of memory barriers.
46 while (irqd_irq_inprogress(&desc->irq_data))
49 /* Ok, that indicated we're done: double-check carefully. */
50 raw_spin_lock_irqsave(&desc->lock, flags);
51 inprogress = irqd_irq_inprogress(&desc->irq_data);
52 raw_spin_unlock_irqrestore(&desc->lock, flags);
54 /* Oops, that failed? */
59 * synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
60 * @irq: interrupt number to wait for
62 * This function waits for any pending hard IRQ handlers for this
63 * interrupt to complete before returning. If you use this
64 * function while holding a resource the IRQ handler may need you
65 * will deadlock. It does not take associated threaded handlers
68 * Do not use this for shutdown scenarios where you must be sure
69 * that all parts (hardirq and threaded handler) have completed.
71 * This function may be called - with care - from IRQ context.
73 void synchronize_hardirq(unsigned int irq)
75 struct irq_desc *desc = irq_to_desc(irq);
78 __synchronize_hardirq(desc);
80 EXPORT_SYMBOL(synchronize_hardirq);
83 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
84 * @irq: interrupt number to wait for
86 * This function waits for any pending IRQ handlers for this interrupt
87 * to complete before returning. If you use this function while
88 * holding a resource the IRQ handler may need you will deadlock.
90 * This function may be called - with care - from IRQ context.
92 void synchronize_irq(unsigned int irq)
94 struct irq_desc *desc = irq_to_desc(irq);
97 __synchronize_hardirq(desc);
99 * We made sure that no hardirq handler is
100 * running. Now verify that no threaded handlers are
103 wait_event(desc->wait_for_threads,
104 !atomic_read(&desc->threads_active));
107 EXPORT_SYMBOL(synchronize_irq);
110 cpumask_var_t irq_default_affinity;
113 * irq_can_set_affinity - Check if the affinity of a given irq can be set
114 * @irq: Interrupt to check
117 int irq_can_set_affinity(unsigned int irq)
119 struct irq_desc *desc = irq_to_desc(irq);
121 if (!desc || !irqd_can_balance(&desc->irq_data) ||
122 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
129 * irq_set_thread_affinity - Notify irq threads to adjust affinity
130 * @desc: irq descriptor which has affitnity changed
132 * We just set IRQTF_AFFINITY and delegate the affinity setting
133 * to the interrupt thread itself. We can not call
134 * set_cpus_allowed_ptr() here as we hold desc->lock and this
135 * code can be called from hard interrupt context.
137 void irq_set_thread_affinity(struct irq_desc *desc)
139 struct irqaction *action = desc->action;
143 set_bit(IRQTF_AFFINITY, &action->thread_flags);
144 action = action->next;
148 #ifdef CONFIG_GENERIC_PENDING_IRQ
149 static inline bool irq_can_move_pcntxt(struct irq_data *data)
151 return irqd_can_move_in_process_context(data);
153 static inline bool irq_move_pending(struct irq_data *data)
155 return irqd_is_setaffinity_pending(data);
158 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
160 cpumask_copy(desc->pending_mask, mask);
163 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
165 cpumask_copy(mask, desc->pending_mask);
168 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
169 static inline bool irq_move_pending(struct irq_data *data) { return false; }
171 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
173 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
176 int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
179 struct irq_desc *desc = irq_data_to_desc(data);
180 struct irq_chip *chip = irq_data_get_irq_chip(data);
183 ret = chip->irq_set_affinity(data, mask, force);
185 case IRQ_SET_MASK_OK:
186 cpumask_copy(data->affinity, mask);
187 case IRQ_SET_MASK_OK_NOCOPY:
188 irq_set_thread_affinity(desc);
195 int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
198 struct irq_chip *chip = irq_data_get_irq_chip(data);
199 struct irq_desc *desc = irq_data_to_desc(data);
202 if (!chip || !chip->irq_set_affinity)
205 if (irq_can_move_pcntxt(data)) {
206 ret = irq_do_set_affinity(data, mask, force);
208 irqd_set_move_pending(data);
209 irq_copy_pending(desc, mask);
212 if (desc->affinity_notify) {
213 kref_get(&desc->affinity_notify->kref);
214 schedule_work(&desc->affinity_notify->work);
216 irqd_set(data, IRQD_AFFINITY_SET);
221 int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
223 struct irq_desc *desc = irq_to_desc(irq);
230 raw_spin_lock_irqsave(&desc->lock, flags);
231 ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
232 raw_spin_unlock_irqrestore(&desc->lock, flags);
236 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
239 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
243 desc->affinity_hint = m;
244 irq_put_desc_unlock(desc, flags);
247 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
249 static void irq_affinity_notify(struct work_struct *work)
251 struct irq_affinity_notify *notify =
252 container_of(work, struct irq_affinity_notify, work);
253 struct irq_desc *desc = irq_to_desc(notify->irq);
254 cpumask_var_t cpumask;
257 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
260 raw_spin_lock_irqsave(&desc->lock, flags);
261 if (irq_move_pending(&desc->irq_data))
262 irq_get_pending(cpumask, desc);
264 cpumask_copy(cpumask, desc->irq_data.affinity);
265 raw_spin_unlock_irqrestore(&desc->lock, flags);
267 notify->notify(notify, cpumask);
269 free_cpumask_var(cpumask);
271 kref_put(¬ify->kref, notify->release);
275 * irq_set_affinity_notifier - control notification of IRQ affinity changes
276 * @irq: Interrupt for which to enable/disable notification
277 * @notify: Context for notification, or %NULL to disable
278 * notification. Function pointers must be initialised;
279 * the other fields will be initialised by this function.
281 * Must be called in process context. Notification may only be enabled
282 * after the IRQ is allocated and must be disabled before the IRQ is
283 * freed using free_irq().
286 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
288 struct irq_desc *desc = irq_to_desc(irq);
289 struct irq_affinity_notify *old_notify;
292 /* The release function is promised process context */
298 /* Complete initialisation of *notify */
301 kref_init(¬ify->kref);
302 INIT_WORK(¬ify->work, irq_affinity_notify);
305 raw_spin_lock_irqsave(&desc->lock, flags);
306 old_notify = desc->affinity_notify;
307 desc->affinity_notify = notify;
308 raw_spin_unlock_irqrestore(&desc->lock, flags);
311 kref_put(&old_notify->kref, old_notify->release);
315 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
317 #ifndef CONFIG_AUTO_IRQ_AFFINITY
319 * Generic version of the affinity autoselector.
322 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
324 struct cpumask *set = irq_default_affinity;
325 int node = desc->irq_data.node;
327 /* Excludes PER_CPU and NO_BALANCE interrupts */
328 if (!irq_can_set_affinity(irq))
332 * Preserve an userspace affinity setup, but make sure that
333 * one of the targets is online.
335 if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
336 if (cpumask_intersects(desc->irq_data.affinity,
338 set = desc->irq_data.affinity;
340 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
343 cpumask_and(mask, cpu_online_mask, set);
344 if (node != NUMA_NO_NODE) {
345 const struct cpumask *nodemask = cpumask_of_node(node);
347 /* make sure at least one of the cpus in nodemask is online */
348 if (cpumask_intersects(mask, nodemask))
349 cpumask_and(mask, mask, nodemask);
351 irq_do_set_affinity(&desc->irq_data, mask, false);
356 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
358 return irq_select_affinity(irq);
363 * Called when affinity is set via /proc/irq
365 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
367 struct irq_desc *desc = irq_to_desc(irq);
371 raw_spin_lock_irqsave(&desc->lock, flags);
372 ret = setup_affinity(irq, desc, mask);
373 raw_spin_unlock_irqrestore(&desc->lock, flags);
379 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
385 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
388 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
390 desc->istate |= IRQS_SUSPENDED;
397 static int __disable_irq_nosync(unsigned int irq)
400 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
404 __disable_irq(desc, irq, false);
405 irq_put_desc_busunlock(desc, flags);
410 * disable_irq_nosync - disable an irq without waiting
411 * @irq: Interrupt to disable
413 * Disable the selected interrupt line. Disables and Enables are
415 * Unlike disable_irq(), this function does not ensure existing
416 * instances of the IRQ handler have completed before returning.
418 * This function may be called from IRQ context.
420 void disable_irq_nosync(unsigned int irq)
422 __disable_irq_nosync(irq);
424 EXPORT_SYMBOL(disable_irq_nosync);
427 * disable_irq - disable an irq and wait for completion
428 * @irq: Interrupt to disable
430 * Disable the selected interrupt line. Enables and Disables are
432 * This function waits for any pending IRQ handlers for this interrupt
433 * to complete before returning. If you use this function while
434 * holding a resource the IRQ handler may need you will deadlock.
436 * This function may be called - with care - from IRQ context.
438 void disable_irq(unsigned int irq)
440 if (!__disable_irq_nosync(irq))
441 synchronize_irq(irq);
443 EXPORT_SYMBOL(disable_irq);
445 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
448 if (!(desc->istate & IRQS_SUSPENDED)) {
451 if (!(desc->action->flags & IRQF_FORCE_RESUME))
453 /* Pretend that it got disabled ! */
456 desc->istate &= ~IRQS_SUSPENDED;
459 switch (desc->depth) {
462 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
465 if (desc->istate & IRQS_SUSPENDED)
467 /* Prevent probing on this irq: */
468 irq_settings_set_noprobe(desc);
470 check_irq_resend(desc, irq);
479 * enable_irq - enable handling of an irq
480 * @irq: Interrupt to enable
482 * Undoes the effect of one call to disable_irq(). If this
483 * matches the last disable, processing of interrupts on this
484 * IRQ line is re-enabled.
486 * This function may be called from IRQ context only when
487 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
489 void enable_irq(unsigned int irq)
492 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
496 if (WARN(!desc->irq_data.chip,
497 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
500 __enable_irq(desc, irq, false);
502 irq_put_desc_busunlock(desc, flags);
504 EXPORT_SYMBOL(enable_irq);
506 static int set_irq_wake_real(unsigned int irq, unsigned int on)
508 struct irq_desc *desc = irq_to_desc(irq);
511 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
514 if (desc->irq_data.chip->irq_set_wake)
515 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
521 * irq_set_irq_wake - control irq power management wakeup
522 * @irq: interrupt to control
523 * @on: enable/disable power management wakeup
525 * Enable/disable power management wakeup mode, which is
526 * disabled by default. Enables and disables must match,
527 * just as they match for non-wakeup mode support.
529 * Wakeup mode lets this IRQ wake the system from sleep
530 * states like "suspend to RAM".
532 int irq_set_irq_wake(unsigned int irq, unsigned int on)
535 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
541 /* wakeup-capable irqs can be shared between drivers that
542 * don't need to have the same sleep mode behaviors.
545 if (desc->wake_depth++ == 0) {
546 ret = set_irq_wake_real(irq, on);
548 desc->wake_depth = 0;
550 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
553 if (desc->wake_depth == 0) {
554 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
555 } else if (--desc->wake_depth == 0) {
556 ret = set_irq_wake_real(irq, on);
558 desc->wake_depth = 1;
560 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
563 irq_put_desc_busunlock(desc, flags);
566 EXPORT_SYMBOL(irq_set_irq_wake);
569 * Internal function that tells the architecture code whether a
570 * particular irq has been exclusively allocated or is available
573 int can_request_irq(unsigned int irq, unsigned long irqflags)
576 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
582 if (irq_settings_can_request(desc)) {
584 irqflags & desc->action->flags & IRQF_SHARED)
587 irq_put_desc_unlock(desc, flags);
591 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
594 struct irq_chip *chip = desc->irq_data.chip;
597 if (!chip || !chip->irq_set_type) {
599 * IRQF_TRIGGER_* but the PIC does not support multiple
602 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
603 chip ? (chip->name ? : "unknown") : "unknown");
607 flags &= IRQ_TYPE_SENSE_MASK;
609 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
610 if (!irqd_irq_masked(&desc->irq_data))
612 if (!irqd_irq_disabled(&desc->irq_data))
616 /* caller masked out all except trigger mode flags */
617 ret = chip->irq_set_type(&desc->irq_data, flags);
620 case IRQ_SET_MASK_OK:
621 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
622 irqd_set(&desc->irq_data, flags);
624 case IRQ_SET_MASK_OK_NOCOPY:
625 flags = irqd_get_trigger_type(&desc->irq_data);
626 irq_settings_set_trigger_mask(desc, flags);
627 irqd_clear(&desc->irq_data, IRQD_LEVEL);
628 irq_settings_clr_level(desc);
629 if (flags & IRQ_TYPE_LEVEL_MASK) {
630 irq_settings_set_level(desc);
631 irqd_set(&desc->irq_data, IRQD_LEVEL);
637 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
638 flags, irq, chip->irq_set_type);
645 #ifdef CONFIG_HARDIRQS_SW_RESEND
646 int irq_set_parent(int irq, int parent_irq)
649 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
654 desc->parent_irq = parent_irq;
656 irq_put_desc_unlock(desc, flags);
662 * Default primary interrupt handler for threaded interrupts. Is
663 * assigned as primary handler when request_threaded_irq is called
664 * with handler == NULL. Useful for oneshot interrupts.
666 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
668 return IRQ_WAKE_THREAD;
672 * Primary handler for nested threaded interrupts. Should never be
675 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
677 WARN(1, "Primary handler called for nested irq %d\n", irq);
681 static int irq_wait_for_interrupt(struct irqaction *action)
683 set_current_state(TASK_INTERRUPTIBLE);
685 while (!kthread_should_stop()) {
687 if (test_and_clear_bit(IRQTF_RUNTHREAD,
688 &action->thread_flags)) {
689 __set_current_state(TASK_RUNNING);
693 set_current_state(TASK_INTERRUPTIBLE);
695 __set_current_state(TASK_RUNNING);
700 * Oneshot interrupts keep the irq line masked until the threaded
701 * handler finished. unmask if the interrupt has not been disabled and
704 static void irq_finalize_oneshot(struct irq_desc *desc,
705 struct irqaction *action)
707 if (!(desc->istate & IRQS_ONESHOT))
711 raw_spin_lock_irq(&desc->lock);
714 * Implausible though it may be we need to protect us against
715 * the following scenario:
717 * The thread is faster done than the hard interrupt handler
718 * on the other CPU. If we unmask the irq line then the
719 * interrupt can come in again and masks the line, leaves due
720 * to IRQS_INPROGRESS and the irq line is masked forever.
722 * This also serializes the state of shared oneshot handlers
723 * versus "desc->threads_onehsot |= action->thread_mask;" in
724 * irq_wake_thread(). See the comment there which explains the
727 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
728 raw_spin_unlock_irq(&desc->lock);
729 chip_bus_sync_unlock(desc);
735 * Now check again, whether the thread should run. Otherwise
736 * we would clear the threads_oneshot bit of this thread which
739 if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
742 desc->threads_oneshot &= ~action->thread_mask;
744 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
745 irqd_irq_masked(&desc->irq_data))
746 unmask_threaded_irq(desc);
749 raw_spin_unlock_irq(&desc->lock);
750 chip_bus_sync_unlock(desc);
755 * Check whether we need to change the affinity of the interrupt thread.
758 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
763 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
767 * In case we are out of memory we set IRQTF_AFFINITY again and
768 * try again next time
770 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
771 set_bit(IRQTF_AFFINITY, &action->thread_flags);
775 raw_spin_lock_irq(&desc->lock);
777 * This code is triggered unconditionally. Check the affinity
778 * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
780 if (desc->irq_data.affinity)
781 cpumask_copy(mask, desc->irq_data.affinity);
784 raw_spin_unlock_irq(&desc->lock);
787 set_cpus_allowed_ptr(current, mask);
788 free_cpumask_var(mask);
792 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
796 * Interrupts which are not explicitely requested as threaded
797 * interrupts rely on the implicit bh/preempt disable of the hard irq
798 * context. So we need to disable bh here to avoid deadlocks and other
802 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
807 ret = action->thread_fn(action->irq, action->dev_id);
808 irq_finalize_oneshot(desc, action);
814 * Interrupts explicitly requested as threaded interrupts want to be
815 * preemtible - many of them need to sleep and wait for slow busses to
818 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
819 struct irqaction *action)
823 ret = action->thread_fn(action->irq, action->dev_id);
824 irq_finalize_oneshot(desc, action);
828 static void wake_threads_waitq(struct irq_desc *desc)
830 if (atomic_dec_and_test(&desc->threads_active))
831 wake_up(&desc->wait_for_threads);
834 static void irq_thread_dtor(struct callback_head *unused)
836 struct task_struct *tsk = current;
837 struct irq_desc *desc;
838 struct irqaction *action;
840 if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
843 action = kthread_data(tsk);
845 pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
846 tsk->comm, tsk->pid, action->irq);
849 desc = irq_to_desc(action->irq);
851 * If IRQTF_RUNTHREAD is set, we need to decrement
852 * desc->threads_active and wake possible waiters.
854 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
855 wake_threads_waitq(desc);
857 /* Prevent a stale desc->threads_oneshot */
858 irq_finalize_oneshot(desc, action);
862 * Interrupt handler thread
864 static int irq_thread(void *data)
866 struct callback_head on_exit_work;
867 struct irqaction *action = data;
868 struct irq_desc *desc = irq_to_desc(action->irq);
869 irqreturn_t (*handler_fn)(struct irq_desc *desc,
870 struct irqaction *action);
872 if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
873 &action->thread_flags))
874 handler_fn = irq_forced_thread_fn;
876 handler_fn = irq_thread_fn;
878 init_task_work(&on_exit_work, irq_thread_dtor);
879 task_work_add(current, &on_exit_work, false);
881 irq_thread_check_affinity(desc, action);
883 while (!irq_wait_for_interrupt(action)) {
884 irqreturn_t action_ret;
886 irq_thread_check_affinity(desc, action);
888 action_ret = handler_fn(desc, action);
890 note_interrupt(action->irq, desc, action_ret);
892 wake_threads_waitq(desc);
896 * This is the regular exit path. __free_irq() is stopping the
897 * thread via kthread_stop() after calling
898 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
899 * oneshot mask bit can be set. We cannot verify that as we
900 * cannot touch the oneshot mask at this point anymore as
901 * __setup_irq() might have given out currents thread_mask
904 task_work_cancel(current, irq_thread_dtor);
909 * irq_wake_thread - wake the irq thread for the action identified by dev_id
910 * @irq: Interrupt line
911 * @dev_id: Device identity for which the thread should be woken
914 void irq_wake_thread(unsigned int irq, void *dev_id)
916 struct irq_desc *desc = irq_to_desc(irq);
917 struct irqaction *action;
920 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
923 raw_spin_lock_irqsave(&desc->lock, flags);
924 for (action = desc->action; action; action = action->next) {
925 if (action->dev_id == dev_id) {
927 __irq_wake_thread(desc, action);
931 raw_spin_unlock_irqrestore(&desc->lock, flags);
933 EXPORT_SYMBOL_GPL(irq_wake_thread);
935 static void irq_setup_forced_threading(struct irqaction *new)
937 if (!force_irqthreads)
939 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
942 new->flags |= IRQF_ONESHOT;
944 if (!new->thread_fn) {
945 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
946 new->thread_fn = new->handler;
947 new->handler = irq_default_primary_handler;
951 static int irq_request_resources(struct irq_desc *desc)
953 struct irq_data *d = &desc->irq_data;
954 struct irq_chip *c = d->chip;
956 return c->irq_request_resources ? c->irq_request_resources(d) : 0;
959 static void irq_release_resources(struct irq_desc *desc)
961 struct irq_data *d = &desc->irq_data;
962 struct irq_chip *c = d->chip;
964 if (c->irq_release_resources)
965 c->irq_release_resources(d);
969 * Internal function to register an irqaction - typically used to
970 * allocate special interrupts that are part of the architecture.
973 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
975 struct irqaction *old, **old_ptr;
976 unsigned long flags, thread_mask = 0;
977 int ret, nested, shared = 0;
983 if (desc->irq_data.chip == &no_irq_chip)
985 if (!try_module_get(desc->owner))
989 * Check whether the interrupt nests into another interrupt
992 nested = irq_settings_is_nested_thread(desc);
994 if (!new->thread_fn) {
999 * Replace the primary handler which was provided from
1000 * the driver for non nested interrupt handling by the
1001 * dummy function which warns when called.
1003 new->handler = irq_nested_primary_handler;
1005 if (irq_settings_can_thread(desc))
1006 irq_setup_forced_threading(new);
1010 * Create a handler thread when a thread function is supplied
1011 * and the interrupt does not nest into another interrupt
1014 if (new->thread_fn && !nested) {
1015 struct task_struct *t;
1016 static const struct sched_param param = {
1017 .sched_priority = MAX_USER_RT_PRIO/2,
1020 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
1027 sched_setscheduler_nocheck(t, SCHED_FIFO, ¶m);
1030 * We keep the reference to the task struct even if
1031 * the thread dies to avoid that the interrupt code
1032 * references an already freed task_struct.
1037 * Tell the thread to set its affinity. This is
1038 * important for shared interrupt handlers as we do
1039 * not invoke setup_affinity() for the secondary
1040 * handlers as everything is already set up. Even for
1041 * interrupts marked with IRQF_NO_BALANCE this is
1042 * correct as we want the thread to move to the cpu(s)
1043 * on which the requesting code placed the interrupt.
1045 set_bit(IRQTF_AFFINITY, &new->thread_flags);
1048 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
1054 * Drivers are often written to work w/o knowledge about the
1055 * underlying irq chip implementation, so a request for a
1056 * threaded irq without a primary hard irq context handler
1057 * requires the ONESHOT flag to be set. Some irq chips like
1058 * MSI based interrupts are per se one shot safe. Check the
1059 * chip flags, so we can avoid the unmask dance at the end of
1060 * the threaded handler for those.
1062 if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
1063 new->flags &= ~IRQF_ONESHOT;
1066 * The following block of code has to be executed atomically
1068 raw_spin_lock_irqsave(&desc->lock, flags);
1069 old_ptr = &desc->action;
1073 * Can't share interrupts unless both agree to and are
1074 * the same type (level, edge, polarity). So both flag
1075 * fields must have IRQF_SHARED set and the bits which
1076 * set the trigger type must match. Also all must
1079 if (!((old->flags & new->flags) & IRQF_SHARED) ||
1080 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
1081 ((old->flags ^ new->flags) & IRQF_ONESHOT))
1084 /* All handlers must agree on per-cpuness */
1085 if ((old->flags & IRQF_PERCPU) !=
1086 (new->flags & IRQF_PERCPU))
1089 /* add new interrupt at end of irq queue */
1092 * Or all existing action->thread_mask bits,
1093 * so we can find the next zero bit for this
1096 thread_mask |= old->thread_mask;
1097 old_ptr = &old->next;
1104 * Setup the thread mask for this irqaction for ONESHOT. For
1105 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1106 * conditional in irq_wake_thread().
1108 if (new->flags & IRQF_ONESHOT) {
1110 * Unlikely to have 32 resp 64 irqs sharing one line,
1113 if (thread_mask == ~0UL) {
1118 * The thread_mask for the action is or'ed to
1119 * desc->thread_active to indicate that the
1120 * IRQF_ONESHOT thread handler has been woken, but not
1121 * yet finished. The bit is cleared when a thread
1122 * completes. When all threads of a shared interrupt
1123 * line have completed desc->threads_active becomes
1124 * zero and the interrupt line is unmasked. See
1125 * handle.c:irq_wake_thread() for further information.
1127 * If no thread is woken by primary (hard irq context)
1128 * interrupt handlers, then desc->threads_active is
1129 * also checked for zero to unmask the irq line in the
1130 * affected hard irq flow handlers
1131 * (handle_[fasteoi|level]_irq).
1133 * The new action gets the first zero bit of
1134 * thread_mask assigned. See the loop above which or's
1135 * all existing action->thread_mask bits.
1137 new->thread_mask = 1 << ffz(thread_mask);
1139 } else if (new->handler == irq_default_primary_handler &&
1140 !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
1142 * The interrupt was requested with handler = NULL, so
1143 * we use the default primary handler for it. But it
1144 * does not have the oneshot flag set. In combination
1145 * with level interrupts this is deadly, because the
1146 * default primary handler just wakes the thread, then
1147 * the irq lines is reenabled, but the device still
1148 * has the level irq asserted. Rinse and repeat....
1150 * While this works for edge type interrupts, we play
1151 * it safe and reject unconditionally because we can't
1152 * say for sure which type this interrupt really
1153 * has. The type flags are unreliable as the
1154 * underlying chip implementation can override them.
1156 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1163 ret = irq_request_resources(desc);
1165 pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
1166 new->name, irq, desc->irq_data.chip->name);
1170 init_waitqueue_head(&desc->wait_for_threads);
1172 /* Setup the type (level, edge polarity) if configured: */
1173 if (new->flags & IRQF_TRIGGER_MASK) {
1174 ret = __irq_set_trigger(desc, irq,
1175 new->flags & IRQF_TRIGGER_MASK);
1181 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1182 IRQS_ONESHOT | IRQS_WAITING);
1183 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1185 if (new->flags & IRQF_PERCPU) {
1186 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1187 irq_settings_set_per_cpu(desc);
1190 if (new->flags & IRQF_ONESHOT)
1191 desc->istate |= IRQS_ONESHOT;
1193 if (irq_settings_can_autoenable(desc))
1194 irq_startup(desc, true);
1196 /* Undo nested disables: */
1199 /* Exclude IRQ from balancing if requested */
1200 if (new->flags & IRQF_NOBALANCING) {
1201 irq_settings_set_no_balancing(desc);
1202 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1205 /* Set default affinity mask once everything is setup */
1206 setup_affinity(irq, desc, mask);
1208 } else if (new->flags & IRQF_TRIGGER_MASK) {
1209 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1210 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1213 /* hope the handler works with current trigger mode */
1214 pr_warning("irq %d uses trigger mode %u; requested %u\n",
1221 /* Reset broken irq detection when installing new handler */
1222 desc->irq_count = 0;
1223 desc->irqs_unhandled = 0;
1226 * Check whether we disabled the irq via the spurious handler
1227 * before. Reenable it and give it another chance.
1229 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1230 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1231 __enable_irq(desc, irq, false);
1234 raw_spin_unlock_irqrestore(&desc->lock, flags);
1237 * Strictly no need to wake it up, but hung_task complains
1238 * when no hard interrupt wakes the thread up.
1241 wake_up_process(new->thread);
1243 register_irq_proc(irq, desc);
1245 register_handler_proc(irq, new);
1246 free_cpumask_var(mask);
1251 if (!(new->flags & IRQF_PROBE_SHARED)) {
1252 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1253 irq, new->flags, new->name, old->flags, old->name);
1254 #ifdef CONFIG_DEBUG_SHIRQ
1261 raw_spin_unlock_irqrestore(&desc->lock, flags);
1262 free_cpumask_var(mask);
1266 struct task_struct *t = new->thread;
1273 module_put(desc->owner);
1278 * setup_irq - setup an interrupt
1279 * @irq: Interrupt line to setup
1280 * @act: irqaction for the interrupt
1282 * Used to statically setup interrupts in the early boot process.
1284 int setup_irq(unsigned int irq, struct irqaction *act)
1287 struct irq_desc *desc = irq_to_desc(irq);
1289 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1291 chip_bus_lock(desc);
1292 retval = __setup_irq(irq, desc, act);
1293 chip_bus_sync_unlock(desc);
1297 EXPORT_SYMBOL_GPL(setup_irq);
1300 * Internal function to unregister an irqaction - used to free
1301 * regular and special interrupts that are part of the architecture.
1303 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1305 struct irq_desc *desc = irq_to_desc(irq);
1306 struct irqaction *action, **action_ptr;
1307 unsigned long flags;
1309 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1314 raw_spin_lock_irqsave(&desc->lock, flags);
1317 * There can be multiple actions per IRQ descriptor, find the right
1318 * one based on the dev_id:
1320 action_ptr = &desc->action;
1322 action = *action_ptr;
1325 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1326 raw_spin_unlock_irqrestore(&desc->lock, flags);
1331 if (action->dev_id == dev_id)
1333 action_ptr = &action->next;
1336 /* Found it - now remove it from the list of entries: */
1337 *action_ptr = action->next;
1339 /* If this was the last handler, shut down the IRQ line: */
1340 if (!desc->action) {
1342 irq_release_resources(desc);
1346 /* make sure affinity_hint is cleaned up */
1347 if (WARN_ON_ONCE(desc->affinity_hint))
1348 desc->affinity_hint = NULL;
1351 raw_spin_unlock_irqrestore(&desc->lock, flags);
1353 unregister_handler_proc(irq, action);
1355 /* Make sure it's not being used on another CPU: */
1356 synchronize_irq(irq);
1358 #ifdef CONFIG_DEBUG_SHIRQ
1360 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1361 * event to happen even now it's being freed, so let's make sure that
1362 * is so by doing an extra call to the handler ....
1364 * ( We do this after actually deregistering it, to make sure that a
1365 * 'real' IRQ doesn't run in * parallel with our fake. )
1367 if (action->flags & IRQF_SHARED) {
1368 local_irq_save(flags);
1369 action->handler(irq, dev_id);
1370 local_irq_restore(flags);
1374 if (action->thread) {
1375 kthread_stop(action->thread);
1376 put_task_struct(action->thread);
1379 module_put(desc->owner);
1384 * remove_irq - free an interrupt
1385 * @irq: Interrupt line to free
1386 * @act: irqaction for the interrupt
1388 * Used to remove interrupts statically setup by the early boot process.
1390 void remove_irq(unsigned int irq, struct irqaction *act)
1392 struct irq_desc *desc = irq_to_desc(irq);
1394 if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1395 __free_irq(irq, act->dev_id);
1397 EXPORT_SYMBOL_GPL(remove_irq);
1400 * free_irq - free an interrupt allocated with request_irq
1401 * @irq: Interrupt line to free
1402 * @dev_id: Device identity to free
1404 * Remove an interrupt handler. The handler is removed and if the
1405 * interrupt line is no longer in use by any driver it is disabled.
1406 * On a shared IRQ the caller must ensure the interrupt is disabled
1407 * on the card it drives before calling this function. The function
1408 * does not return until any executing interrupts for this IRQ
1411 * This function must not be called from interrupt context.
1413 void free_irq(unsigned int irq, void *dev_id)
1415 struct irq_desc *desc = irq_to_desc(irq);
1417 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1421 if (WARN_ON(desc->affinity_notify))
1422 desc->affinity_notify = NULL;
1425 chip_bus_lock(desc);
1426 kfree(__free_irq(irq, dev_id));
1427 chip_bus_sync_unlock(desc);
1429 EXPORT_SYMBOL(free_irq);
1432 * request_threaded_irq - allocate an interrupt line
1433 * @irq: Interrupt line to allocate
1434 * @handler: Function to be called when the IRQ occurs.
1435 * Primary handler for threaded interrupts
1436 * If NULL and thread_fn != NULL the default
1437 * primary handler is installed
1438 * @thread_fn: Function called from the irq handler thread
1439 * If NULL, no irq thread is created
1440 * @irqflags: Interrupt type flags
1441 * @devname: An ascii name for the claiming device
1442 * @dev_id: A cookie passed back to the handler function
1444 * This call allocates interrupt resources and enables the
1445 * interrupt line and IRQ handling. From the point this
1446 * call is made your handler function may be invoked. Since
1447 * your handler function must clear any interrupt the board
1448 * raises, you must take care both to initialise your hardware
1449 * and to set up the interrupt handler in the right order.
1451 * If you want to set up a threaded irq handler for your device
1452 * then you need to supply @handler and @thread_fn. @handler is
1453 * still called in hard interrupt context and has to check
1454 * whether the interrupt originates from the device. If yes it
1455 * needs to disable the interrupt on the device and return
1456 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1457 * @thread_fn. This split handler design is necessary to support
1458 * shared interrupts.
1460 * Dev_id must be globally unique. Normally the address of the
1461 * device data structure is used as the cookie. Since the handler
1462 * receives this value it makes sense to use it.
1464 * If your interrupt is shared you must pass a non NULL dev_id
1465 * as this is required when freeing the interrupt.
1469 * IRQF_SHARED Interrupt is shared
1470 * IRQF_TRIGGER_* Specify active edge(s) or level
1473 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1474 irq_handler_t thread_fn, unsigned long irqflags,
1475 const char *devname, void *dev_id)
1477 struct irqaction *action;
1478 struct irq_desc *desc;
1482 * Sanity-check: shared interrupts must pass in a real dev-ID,
1483 * otherwise we'll have trouble later trying to figure out
1484 * which interrupt is which (messes up the interrupt freeing
1487 if ((irqflags & IRQF_SHARED) && !dev_id)
1490 desc = irq_to_desc(irq);
1494 if (!irq_settings_can_request(desc) ||
1495 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1501 handler = irq_default_primary_handler;
1504 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1508 action->handler = handler;
1509 action->thread_fn = thread_fn;
1510 action->flags = irqflags;
1511 action->name = devname;
1512 action->dev_id = dev_id;
1514 chip_bus_lock(desc);
1515 retval = __setup_irq(irq, desc, action);
1516 chip_bus_sync_unlock(desc);
1521 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1522 if (!retval && (irqflags & IRQF_SHARED)) {
1524 * It's a shared IRQ -- the driver ought to be prepared for it
1525 * to happen immediately, so let's make sure....
1526 * We disable the irq to make sure that a 'real' IRQ doesn't
1527 * run in parallel with our fake.
1529 unsigned long flags;
1532 local_irq_save(flags);
1534 handler(irq, dev_id);
1536 local_irq_restore(flags);
1542 EXPORT_SYMBOL(request_threaded_irq);
1545 * request_any_context_irq - allocate an interrupt line
1546 * @irq: Interrupt line to allocate
1547 * @handler: Function to be called when the IRQ occurs.
1548 * Threaded handler for threaded interrupts.
1549 * @flags: Interrupt type flags
1550 * @name: An ascii name for the claiming device
1551 * @dev_id: A cookie passed back to the handler function
1553 * This call allocates interrupt resources and enables the
1554 * interrupt line and IRQ handling. It selects either a
1555 * hardirq or threaded handling method depending on the
1558 * On failure, it returns a negative value. On success,
1559 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1561 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1562 unsigned long flags, const char *name, void *dev_id)
1564 struct irq_desc *desc = irq_to_desc(irq);
1570 if (irq_settings_is_nested_thread(desc)) {
1571 ret = request_threaded_irq(irq, NULL, handler,
1572 flags, name, dev_id);
1573 return !ret ? IRQC_IS_NESTED : ret;
1576 ret = request_irq(irq, handler, flags, name, dev_id);
1577 return !ret ? IRQC_IS_HARDIRQ : ret;
1579 EXPORT_SYMBOL_GPL(request_any_context_irq);
1581 void enable_percpu_irq(unsigned int irq, unsigned int type)
1583 unsigned int cpu = smp_processor_id();
1584 unsigned long flags;
1585 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1590 type &= IRQ_TYPE_SENSE_MASK;
1591 if (type != IRQ_TYPE_NONE) {
1594 ret = __irq_set_trigger(desc, irq, type);
1597 WARN(1, "failed to set type for IRQ%d\n", irq);
1602 irq_percpu_enable(desc, cpu);
1604 irq_put_desc_unlock(desc, flags);
1606 EXPORT_SYMBOL_GPL(enable_percpu_irq);
1608 void disable_percpu_irq(unsigned int irq)
1610 unsigned int cpu = smp_processor_id();
1611 unsigned long flags;
1612 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1617 irq_percpu_disable(desc, cpu);
1618 irq_put_desc_unlock(desc, flags);
1620 EXPORT_SYMBOL_GPL(disable_percpu_irq);
1623 * Internal function to unregister a percpu irqaction.
1625 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1627 struct irq_desc *desc = irq_to_desc(irq);
1628 struct irqaction *action;
1629 unsigned long flags;
1631 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1636 raw_spin_lock_irqsave(&desc->lock, flags);
1638 action = desc->action;
1639 if (!action || action->percpu_dev_id != dev_id) {
1640 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1644 if (!cpumask_empty(desc->percpu_enabled)) {
1645 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1646 irq, cpumask_first(desc->percpu_enabled));
1650 /* Found it - now remove it from the list of entries: */
1651 desc->action = NULL;
1653 raw_spin_unlock_irqrestore(&desc->lock, flags);
1655 unregister_handler_proc(irq, action);
1657 module_put(desc->owner);
1661 raw_spin_unlock_irqrestore(&desc->lock, flags);
1666 * remove_percpu_irq - free a per-cpu interrupt
1667 * @irq: Interrupt line to free
1668 * @act: irqaction for the interrupt
1670 * Used to remove interrupts statically setup by the early boot process.
1672 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1674 struct irq_desc *desc = irq_to_desc(irq);
1676 if (desc && irq_settings_is_per_cpu_devid(desc))
1677 __free_percpu_irq(irq, act->percpu_dev_id);
1681 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
1682 * @irq: Interrupt line to free
1683 * @dev_id: Device identity to free
1685 * Remove a percpu interrupt handler. The handler is removed, but
1686 * the interrupt line is not disabled. This must be done on each
1687 * CPU before calling this function. The function does not return
1688 * until any executing interrupts for this IRQ have completed.
1690 * This function must not be called from interrupt context.
1692 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1694 struct irq_desc *desc = irq_to_desc(irq);
1696 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1699 chip_bus_lock(desc);
1700 kfree(__free_percpu_irq(irq, dev_id));
1701 chip_bus_sync_unlock(desc);
1705 * setup_percpu_irq - setup a per-cpu interrupt
1706 * @irq: Interrupt line to setup
1707 * @act: irqaction for the interrupt
1709 * Used to statically setup per-cpu interrupts in the early boot process.
1711 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1713 struct irq_desc *desc = irq_to_desc(irq);
1716 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1718 chip_bus_lock(desc);
1719 retval = __setup_irq(irq, desc, act);
1720 chip_bus_sync_unlock(desc);
1726 * request_percpu_irq - allocate a percpu interrupt line
1727 * @irq: Interrupt line to allocate
1728 * @handler: Function to be called when the IRQ occurs.
1729 * @devname: An ascii name for the claiming device
1730 * @dev_id: A percpu cookie passed back to the handler function
1732 * This call allocates interrupt resources, but doesn't
1733 * automatically enable the interrupt. It has to be done on each
1734 * CPU using enable_percpu_irq().
1736 * Dev_id must be globally unique. It is a per-cpu variable, and
1737 * the handler gets called with the interrupted CPU's instance of
1740 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1741 const char *devname, void __percpu *dev_id)
1743 struct irqaction *action;
1744 struct irq_desc *desc;
1750 desc = irq_to_desc(irq);
1751 if (!desc || !irq_settings_can_request(desc) ||
1752 !irq_settings_is_per_cpu_devid(desc))
1755 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1759 action->handler = handler;
1760 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1761 action->name = devname;
1762 action->percpu_dev_id = dev_id;
1764 chip_bus_lock(desc);
1765 retval = __setup_irq(irq, desc, action);
1766 chip_bus_sync_unlock(desc);