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>
20 #include "internals.h"
22 #ifdef CONFIG_IRQ_FORCED_THREADING
23 __read_mostly bool force_irqthreads;
25 static int __init setup_forced_irqthreads(char *arg)
27 force_irqthreads = true;
30 early_param("threadirqs", setup_forced_irqthreads);
34 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
35 * @irq: interrupt number to wait for
37 * This function waits for any pending IRQ handlers for this interrupt
38 * to complete before returning. If you use this function while
39 * holding a resource the IRQ handler may need you will deadlock.
41 * This function may be called - with care - from IRQ context.
43 void synchronize_irq(unsigned int irq)
45 struct irq_desc *desc = irq_to_desc(irq);
55 * Wait until we're out of the critical section. This might
56 * give the wrong answer due to the lack of memory barriers.
58 while (irqd_irq_inprogress(&desc->irq_data))
61 /* Ok, that indicated we're done: double-check carefully. */
62 raw_spin_lock_irqsave(&desc->lock, flags);
63 inprogress = irqd_irq_inprogress(&desc->irq_data);
64 raw_spin_unlock_irqrestore(&desc->lock, flags);
66 /* Oops, that failed? */
70 * We made sure that no hardirq handler is running. Now verify
71 * that no threaded handlers are active.
73 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
75 EXPORT_SYMBOL(synchronize_irq);
78 cpumask_var_t irq_default_affinity;
81 * irq_can_set_affinity - Check if the affinity of a given irq can be set
82 * @irq: Interrupt to check
85 int irq_can_set_affinity(unsigned int irq)
87 struct irq_desc *desc = irq_to_desc(irq);
89 if (!desc || !irqd_can_balance(&desc->irq_data) ||
90 !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
97 * irq_set_thread_affinity - Notify irq threads to adjust affinity
98 * @desc: irq descriptor which has affitnity changed
100 * We just set IRQTF_AFFINITY and delegate the affinity setting
101 * to the interrupt thread itself. We can not call
102 * set_cpus_allowed_ptr() here as we hold desc->lock and this
103 * code can be called from hard interrupt context.
105 void irq_set_thread_affinity(struct irq_desc *desc)
107 struct irqaction *action = desc->action;
111 set_bit(IRQTF_AFFINITY, &action->thread_flags);
112 action = action->next;
116 #ifdef CONFIG_GENERIC_PENDING_IRQ
117 static inline bool irq_can_move_pcntxt(struct irq_data *data)
119 return irqd_can_move_in_process_context(data);
121 static inline bool irq_move_pending(struct irq_data *data)
123 return irqd_is_setaffinity_pending(data);
126 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
128 cpumask_copy(desc->pending_mask, mask);
131 irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
133 cpumask_copy(mask, desc->pending_mask);
136 static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
137 static inline bool irq_move_pending(struct irq_data *data) { return false; }
139 irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
141 irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
144 int __irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask)
146 struct irq_chip *chip = irq_data_get_irq_chip(data);
147 struct irq_desc *desc = irq_data_to_desc(data);
150 if (!chip || !chip->irq_set_affinity)
153 if (irq_can_move_pcntxt(data)) {
154 ret = chip->irq_set_affinity(data, mask, false);
156 case IRQ_SET_MASK_OK:
157 cpumask_copy(data->affinity, mask);
158 case IRQ_SET_MASK_OK_NOCOPY:
159 irq_set_thread_affinity(desc);
163 irqd_set_move_pending(data);
164 irq_copy_pending(desc, mask);
167 if (desc->affinity_notify) {
168 kref_get(&desc->affinity_notify->kref);
169 schedule_work(&desc->affinity_notify->work);
171 irqd_set(data, IRQD_AFFINITY_SET);
177 * irq_set_affinity - Set the irq affinity of a given irq
178 * @irq: Interrupt to set affinity
182 int irq_set_affinity(unsigned int irq, const struct cpumask *mask)
184 struct irq_desc *desc = irq_to_desc(irq);
191 raw_spin_lock_irqsave(&desc->lock, flags);
192 ret = __irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask);
193 raw_spin_unlock_irqrestore(&desc->lock, flags);
197 int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
200 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
204 desc->affinity_hint = m;
205 irq_put_desc_unlock(desc, flags);
208 EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
210 static void irq_affinity_notify(struct work_struct *work)
212 struct irq_affinity_notify *notify =
213 container_of(work, struct irq_affinity_notify, work);
214 struct irq_desc *desc = irq_to_desc(notify->irq);
215 cpumask_var_t cpumask;
218 if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
221 raw_spin_lock_irqsave(&desc->lock, flags);
222 if (irq_move_pending(&desc->irq_data))
223 irq_get_pending(cpumask, desc);
225 cpumask_copy(cpumask, desc->irq_data.affinity);
226 raw_spin_unlock_irqrestore(&desc->lock, flags);
228 notify->notify(notify, cpumask);
230 free_cpumask_var(cpumask);
232 kref_put(¬ify->kref, notify->release);
236 * irq_set_affinity_notifier - control notification of IRQ affinity changes
237 * @irq: Interrupt for which to enable/disable notification
238 * @notify: Context for notification, or %NULL to disable
239 * notification. Function pointers must be initialised;
240 * the other fields will be initialised by this function.
242 * Must be called in process context. Notification may only be enabled
243 * after the IRQ is allocated and must be disabled before the IRQ is
244 * freed using free_irq().
247 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
249 struct irq_desc *desc = irq_to_desc(irq);
250 struct irq_affinity_notify *old_notify;
253 /* The release function is promised process context */
259 /* Complete initialisation of *notify */
262 kref_init(¬ify->kref);
263 INIT_WORK(¬ify->work, irq_affinity_notify);
266 raw_spin_lock_irqsave(&desc->lock, flags);
267 old_notify = desc->affinity_notify;
268 desc->affinity_notify = notify;
269 raw_spin_unlock_irqrestore(&desc->lock, flags);
272 kref_put(&old_notify->kref, old_notify->release);
276 EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
278 #ifndef CONFIG_AUTO_IRQ_AFFINITY
280 * Generic version of the affinity autoselector.
283 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
285 struct irq_chip *chip = irq_desc_get_chip(desc);
286 struct cpumask *set = irq_default_affinity;
287 int ret, node = desc->irq_data.node;
289 /* Excludes PER_CPU and NO_BALANCE interrupts */
290 if (!irq_can_set_affinity(irq))
294 * Preserve an userspace affinity setup, but make sure that
295 * one of the targets is online.
297 if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
298 if (cpumask_intersects(desc->irq_data.affinity,
300 set = desc->irq_data.affinity;
302 irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
305 cpumask_and(mask, cpu_online_mask, set);
306 if (node != NUMA_NO_NODE) {
307 const struct cpumask *nodemask = cpumask_of_node(node);
309 /* make sure at least one of the cpus in nodemask is online */
310 if (cpumask_intersects(mask, nodemask))
311 cpumask_and(mask, mask, nodemask);
313 ret = chip->irq_set_affinity(&desc->irq_data, mask, false);
315 case IRQ_SET_MASK_OK:
316 cpumask_copy(desc->irq_data.affinity, mask);
317 case IRQ_SET_MASK_OK_NOCOPY:
318 irq_set_thread_affinity(desc);
324 setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
326 return irq_select_affinity(irq);
331 * Called when affinity is set via /proc/irq
333 int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
335 struct irq_desc *desc = irq_to_desc(irq);
339 raw_spin_lock_irqsave(&desc->lock, flags);
340 ret = setup_affinity(irq, desc, mask);
341 raw_spin_unlock_irqrestore(&desc->lock, flags);
347 setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
353 void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
356 if (!desc->action || (desc->action->flags & IRQF_NO_SUSPEND))
358 desc->istate |= IRQS_SUSPENDED;
365 static int __disable_irq_nosync(unsigned int irq)
368 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
372 __disable_irq(desc, irq, false);
373 irq_put_desc_busunlock(desc, flags);
378 * disable_irq_nosync - disable an irq without waiting
379 * @irq: Interrupt to disable
381 * Disable the selected interrupt line. Disables and Enables are
383 * Unlike disable_irq(), this function does not ensure existing
384 * instances of the IRQ handler have completed before returning.
386 * This function may be called from IRQ context.
388 void disable_irq_nosync(unsigned int irq)
390 __disable_irq_nosync(irq);
392 EXPORT_SYMBOL(disable_irq_nosync);
395 * disable_irq - disable an irq and wait for completion
396 * @irq: Interrupt to disable
398 * Disable the selected interrupt line. Enables and Disables are
400 * This function waits for any pending IRQ handlers for this interrupt
401 * to complete before returning. If you use this function while
402 * holding a resource the IRQ handler may need you will deadlock.
404 * This function may be called - with care - from IRQ context.
406 void disable_irq(unsigned int irq)
408 if (!__disable_irq_nosync(irq))
409 synchronize_irq(irq);
411 EXPORT_SYMBOL(disable_irq);
413 void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
416 if (!(desc->istate & IRQS_SUSPENDED)) {
419 if (!(desc->action->flags & IRQF_FORCE_RESUME))
421 /* Pretend that it got disabled ! */
424 desc->istate &= ~IRQS_SUSPENDED;
427 switch (desc->depth) {
430 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
433 if (desc->istate & IRQS_SUSPENDED)
435 /* Prevent probing on this irq: */
436 irq_settings_set_noprobe(desc);
438 check_irq_resend(desc, irq);
447 * enable_irq - enable handling of an irq
448 * @irq: Interrupt to enable
450 * Undoes the effect of one call to disable_irq(). If this
451 * matches the last disable, processing of interrupts on this
452 * IRQ line is re-enabled.
454 * This function may be called from IRQ context only when
455 * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
457 void enable_irq(unsigned int irq)
460 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
464 if (WARN(!desc->irq_data.chip,
465 KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
468 __enable_irq(desc, irq, false);
470 irq_put_desc_busunlock(desc, flags);
472 EXPORT_SYMBOL(enable_irq);
474 static int set_irq_wake_real(unsigned int irq, unsigned int on)
476 struct irq_desc *desc = irq_to_desc(irq);
479 if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
482 if (desc->irq_data.chip->irq_set_wake)
483 ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
489 * irq_set_irq_wake - control irq power management wakeup
490 * @irq: interrupt to control
491 * @on: enable/disable power management wakeup
493 * Enable/disable power management wakeup mode, which is
494 * disabled by default. Enables and disables must match,
495 * just as they match for non-wakeup mode support.
497 * Wakeup mode lets this IRQ wake the system from sleep
498 * states like "suspend to RAM".
500 int irq_set_irq_wake(unsigned int irq, unsigned int on)
503 struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
509 /* wakeup-capable irqs can be shared between drivers that
510 * don't need to have the same sleep mode behaviors.
513 if (desc->wake_depth++ == 0) {
514 ret = set_irq_wake_real(irq, on);
516 desc->wake_depth = 0;
518 irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
521 if (desc->wake_depth == 0) {
522 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
523 } else if (--desc->wake_depth == 0) {
524 ret = set_irq_wake_real(irq, on);
526 desc->wake_depth = 1;
528 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
531 irq_put_desc_busunlock(desc, flags);
534 EXPORT_SYMBOL(irq_set_irq_wake);
537 * Internal function that tells the architecture code whether a
538 * particular irq has been exclusively allocated or is available
541 int can_request_irq(unsigned int irq, unsigned long irqflags)
544 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
550 if (irq_settings_can_request(desc)) {
552 if (irqflags & desc->action->flags & IRQF_SHARED)
555 irq_put_desc_unlock(desc, flags);
559 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
562 struct irq_chip *chip = desc->irq_data.chip;
565 if (!chip || !chip->irq_set_type) {
567 * IRQF_TRIGGER_* but the PIC does not support multiple
570 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
571 chip ? (chip->name ? : "unknown") : "unknown");
575 flags &= IRQ_TYPE_SENSE_MASK;
577 if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
578 if (!irqd_irq_masked(&desc->irq_data))
580 if (!irqd_irq_disabled(&desc->irq_data))
584 /* caller masked out all except trigger mode flags */
585 ret = chip->irq_set_type(&desc->irq_data, flags);
588 case IRQ_SET_MASK_OK:
589 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
590 irqd_set(&desc->irq_data, flags);
592 case IRQ_SET_MASK_OK_NOCOPY:
593 flags = irqd_get_trigger_type(&desc->irq_data);
594 irq_settings_set_trigger_mask(desc, flags);
595 irqd_clear(&desc->irq_data, IRQD_LEVEL);
596 irq_settings_clr_level(desc);
597 if (flags & IRQ_TYPE_LEVEL_MASK) {
598 irq_settings_set_level(desc);
599 irqd_set(&desc->irq_data, IRQD_LEVEL);
605 pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
606 flags, irq, chip->irq_set_type);
614 * Default primary interrupt handler for threaded interrupts. Is
615 * assigned as primary handler when request_threaded_irq is called
616 * with handler == NULL. Useful for oneshot interrupts.
618 static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
620 return IRQ_WAKE_THREAD;
624 * Primary handler for nested threaded interrupts. Should never be
627 static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
629 WARN(1, "Primary handler called for nested irq %d\n", irq);
633 static int irq_wait_for_interrupt(struct irqaction *action)
635 set_current_state(TASK_INTERRUPTIBLE);
637 while (!kthread_should_stop()) {
639 if (test_and_clear_bit(IRQTF_RUNTHREAD,
640 &action->thread_flags)) {
641 __set_current_state(TASK_RUNNING);
645 set_current_state(TASK_INTERRUPTIBLE);
647 __set_current_state(TASK_RUNNING);
652 * Oneshot interrupts keep the irq line masked until the threaded
653 * handler finished. unmask if the interrupt has not been disabled and
656 static void irq_finalize_oneshot(struct irq_desc *desc,
657 struct irqaction *action)
659 if (!(desc->istate & IRQS_ONESHOT))
663 raw_spin_lock_irq(&desc->lock);
666 * Implausible though it may be we need to protect us against
667 * the following scenario:
669 * The thread is faster done than the hard interrupt handler
670 * on the other CPU. If we unmask the irq line then the
671 * interrupt can come in again and masks the line, leaves due
672 * to IRQS_INPROGRESS and the irq line is masked forever.
674 * This also serializes the state of shared oneshot handlers
675 * versus "desc->threads_onehsot |= action->thread_mask;" in
676 * irq_wake_thread(). See the comment there which explains the
679 if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
680 raw_spin_unlock_irq(&desc->lock);
681 chip_bus_sync_unlock(desc);
687 * Now check again, whether the thread should run. Otherwise
688 * we would clear the threads_oneshot bit of this thread which
691 if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
694 desc->threads_oneshot &= ~action->thread_mask;
696 if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
697 irqd_irq_masked(&desc->irq_data))
701 raw_spin_unlock_irq(&desc->lock);
702 chip_bus_sync_unlock(desc);
707 * Check whether we need to chasnge the affinity of the interrupt thread.
710 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
714 if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
718 * In case we are out of memory we set IRQTF_AFFINITY again and
719 * try again next time
721 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
722 set_bit(IRQTF_AFFINITY, &action->thread_flags);
726 raw_spin_lock_irq(&desc->lock);
727 cpumask_copy(mask, desc->irq_data.affinity);
728 raw_spin_unlock_irq(&desc->lock);
730 set_cpus_allowed_ptr(current, mask);
731 free_cpumask_var(mask);
735 irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
739 * Interrupts which are not explicitely requested as threaded
740 * interrupts rely on the implicit bh/preempt disable of the hard irq
741 * context. So we need to disable bh here to avoid deadlocks and other
745 irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
750 ret = action->thread_fn(action->irq, action->dev_id);
751 irq_finalize_oneshot(desc, action);
757 * Interrupts explicitely requested as threaded interupts want to be
758 * preemtible - many of them need to sleep and wait for slow busses to
761 static irqreturn_t irq_thread_fn(struct irq_desc *desc,
762 struct irqaction *action)
766 ret = action->thread_fn(action->irq, action->dev_id);
767 irq_finalize_oneshot(desc, action);
771 static void wake_threads_waitq(struct irq_desc *desc)
773 if (atomic_dec_and_test(&desc->threads_active) &&
774 waitqueue_active(&desc->wait_for_threads))
775 wake_up(&desc->wait_for_threads);
779 * Interrupt handler thread
781 static int irq_thread(void *data)
783 static const struct sched_param param = {
784 .sched_priority = MAX_USER_RT_PRIO/2,
786 struct irqaction *action = data;
787 struct irq_desc *desc = irq_to_desc(action->irq);
788 irqreturn_t (*handler_fn)(struct irq_desc *desc,
789 struct irqaction *action);
791 if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
792 &action->thread_flags))
793 handler_fn = irq_forced_thread_fn;
795 handler_fn = irq_thread_fn;
797 sched_setscheduler(current, SCHED_FIFO, ¶m);
798 current->irq_thread = 1;
800 while (!irq_wait_for_interrupt(action)) {
801 irqreturn_t action_ret;
803 irq_thread_check_affinity(desc, action);
805 action_ret = handler_fn(desc, action);
807 note_interrupt(action->irq, desc, action_ret);
809 wake_threads_waitq(desc);
813 * This is the regular exit path. __free_irq() is stopping the
814 * thread via kthread_stop() after calling
815 * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
816 * oneshot mask bit can be set. We cannot verify that as we
817 * cannot touch the oneshot mask at this point anymore as
818 * __setup_irq() might have given out currents thread_mask
821 * Clear irq_thread. Otherwise exit_irq_thread() would make
822 * fuzz about an active irq thread going into nirvana.
824 current->irq_thread = 0;
829 * Called from do_exit()
831 void exit_irq_thread(void)
833 struct task_struct *tsk = current;
834 struct irq_desc *desc;
835 struct irqaction *action;
837 if (!tsk->irq_thread)
840 action = kthread_data(tsk);
842 pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
843 tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
845 desc = irq_to_desc(action->irq);
848 * If IRQTF_RUNTHREAD is set, we need to decrement
849 * desc->threads_active and wake possible waiters.
851 if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
852 wake_threads_waitq(desc);
854 /* Prevent a stale desc->threads_oneshot */
855 irq_finalize_oneshot(desc, action);
858 static void irq_setup_forced_threading(struct irqaction *new)
860 if (!force_irqthreads)
862 if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
865 new->flags |= IRQF_ONESHOT;
867 if (!new->thread_fn) {
868 set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
869 new->thread_fn = new->handler;
870 new->handler = irq_default_primary_handler;
875 * Internal function to register an irqaction - typically used to
876 * allocate special interrupts that are part of the architecture.
879 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
881 struct irqaction *old, **old_ptr;
882 unsigned long flags, thread_mask = 0;
883 int ret, nested, shared = 0;
889 if (desc->irq_data.chip == &no_irq_chip)
891 if (!try_module_get(desc->owner))
894 * Some drivers like serial.c use request_irq() heavily,
895 * so we have to be careful not to interfere with a
898 if (new->flags & IRQF_SAMPLE_RANDOM) {
900 * This function might sleep, we want to call it first,
901 * outside of the atomic block.
902 * Yes, this might clear the entropy pool if the wrong
903 * driver is attempted to be loaded, without actually
904 * installing a new handler, but is this really a problem,
905 * only the sysadmin is able to do this.
907 rand_initialize_irq(irq);
911 * Check whether the interrupt nests into another interrupt
914 nested = irq_settings_is_nested_thread(desc);
916 if (!new->thread_fn) {
921 * Replace the primary handler which was provided from
922 * the driver for non nested interrupt handling by the
923 * dummy function which warns when called.
925 new->handler = irq_nested_primary_handler;
927 if (irq_settings_can_thread(desc))
928 irq_setup_forced_threading(new);
932 * Create a handler thread when a thread function is supplied
933 * and the interrupt does not nest into another interrupt
936 if (new->thread_fn && !nested) {
937 struct task_struct *t;
939 t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
946 * We keep the reference to the task struct even if
947 * the thread dies to avoid that the interrupt code
948 * references an already freed task_struct.
954 if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
960 * The following block of code has to be executed atomically
962 raw_spin_lock_irqsave(&desc->lock, flags);
963 old_ptr = &desc->action;
967 * Can't share interrupts unless both agree to and are
968 * the same type (level, edge, polarity). So both flag
969 * fields must have IRQF_SHARED set and the bits which
970 * set the trigger type must match. Also all must
973 if (!((old->flags & new->flags) & IRQF_SHARED) ||
974 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
975 ((old->flags ^ new->flags) & IRQF_ONESHOT))
978 /* All handlers must agree on per-cpuness */
979 if ((old->flags & IRQF_PERCPU) !=
980 (new->flags & IRQF_PERCPU))
983 /* add new interrupt at end of irq queue */
986 * Or all existing action->thread_mask bits,
987 * so we can find the next zero bit for this
990 thread_mask |= old->thread_mask;
991 old_ptr = &old->next;
998 * Setup the thread mask for this irqaction for ONESHOT. For
999 * !ONESHOT irqs the thread mask is 0 so we can avoid a
1000 * conditional in irq_wake_thread().
1002 if (new->flags & IRQF_ONESHOT) {
1004 * Unlikely to have 32 resp 64 irqs sharing one line,
1007 if (thread_mask == ~0UL) {
1012 * The thread_mask for the action is or'ed to
1013 * desc->thread_active to indicate that the
1014 * IRQF_ONESHOT thread handler has been woken, but not
1015 * yet finished. The bit is cleared when a thread
1016 * completes. When all threads of a shared interrupt
1017 * line have completed desc->threads_active becomes
1018 * zero and the interrupt line is unmasked. See
1019 * handle.c:irq_wake_thread() for further information.
1021 * If no thread is woken by primary (hard irq context)
1022 * interrupt handlers, then desc->threads_active is
1023 * also checked for zero to unmask the irq line in the
1024 * affected hard irq flow handlers
1025 * (handle_[fasteoi|level]_irq).
1027 * The new action gets the first zero bit of
1028 * thread_mask assigned. See the loop above which or's
1029 * all existing action->thread_mask bits.
1031 new->thread_mask = 1 << ffz(thread_mask);
1033 } else if (new->handler == irq_default_primary_handler) {
1035 * The interrupt was requested with handler = NULL, so
1036 * we use the default primary handler for it. But it
1037 * does not have the oneshot flag set. In combination
1038 * with level interrupts this is deadly, because the
1039 * default primary handler just wakes the thread, then
1040 * the irq lines is reenabled, but the device still
1041 * has the level irq asserted. Rinse and repeat....
1043 * While this works for edge type interrupts, we play
1044 * it safe and reject unconditionally because we can't
1045 * say for sure which type this interrupt really
1046 * has. The type flags are unreliable as the
1047 * underlying chip implementation can override them.
1049 pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
1056 init_waitqueue_head(&desc->wait_for_threads);
1058 /* Setup the type (level, edge polarity) if configured: */
1059 if (new->flags & IRQF_TRIGGER_MASK) {
1060 ret = __irq_set_trigger(desc, irq,
1061 new->flags & IRQF_TRIGGER_MASK);
1067 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
1068 IRQS_ONESHOT | IRQS_WAITING);
1069 irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
1071 if (new->flags & IRQF_PERCPU) {
1072 irqd_set(&desc->irq_data, IRQD_PER_CPU);
1073 irq_settings_set_per_cpu(desc);
1076 if (new->flags & IRQF_ONESHOT)
1077 desc->istate |= IRQS_ONESHOT;
1079 if (irq_settings_can_autoenable(desc))
1080 irq_startup(desc, true);
1082 /* Undo nested disables: */
1085 /* Exclude IRQ from balancing if requested */
1086 if (new->flags & IRQF_NOBALANCING) {
1087 irq_settings_set_no_balancing(desc);
1088 irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
1091 /* Set default affinity mask once everything is setup */
1092 setup_affinity(irq, desc, mask);
1094 } else if (new->flags & IRQF_TRIGGER_MASK) {
1095 unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
1096 unsigned int omsk = irq_settings_get_trigger_mask(desc);
1099 /* hope the handler works with current trigger mode */
1100 pr_warning("irq %d uses trigger mode %u; requested %u\n",
1107 /* Reset broken irq detection when installing new handler */
1108 desc->irq_count = 0;
1109 desc->irqs_unhandled = 0;
1112 * Check whether we disabled the irq via the spurious handler
1113 * before. Reenable it and give it another chance.
1115 if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
1116 desc->istate &= ~IRQS_SPURIOUS_DISABLED;
1117 __enable_irq(desc, irq, false);
1120 raw_spin_unlock_irqrestore(&desc->lock, flags);
1123 * Strictly no need to wake it up, but hung_task complains
1124 * when no hard interrupt wakes the thread up.
1127 wake_up_process(new->thread);
1129 register_irq_proc(irq, desc);
1131 register_handler_proc(irq, new);
1132 free_cpumask_var(mask);
1137 if (!(new->flags & IRQF_PROBE_SHARED)) {
1138 pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
1139 irq, new->flags, new->name, old->flags, old->name);
1140 #ifdef CONFIG_DEBUG_SHIRQ
1147 raw_spin_unlock_irqrestore(&desc->lock, flags);
1148 free_cpumask_var(mask);
1152 struct task_struct *t = new->thread;
1159 module_put(desc->owner);
1164 * setup_irq - setup an interrupt
1165 * @irq: Interrupt line to setup
1166 * @act: irqaction for the interrupt
1168 * Used to statically setup interrupts in the early boot process.
1170 int setup_irq(unsigned int irq, struct irqaction *act)
1173 struct irq_desc *desc = irq_to_desc(irq);
1175 if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1177 chip_bus_lock(desc);
1178 retval = __setup_irq(irq, desc, act);
1179 chip_bus_sync_unlock(desc);
1183 EXPORT_SYMBOL_GPL(setup_irq);
1186 * Internal function to unregister an irqaction - used to free
1187 * regular and special interrupts that are part of the architecture.
1189 static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
1191 struct irq_desc *desc = irq_to_desc(irq);
1192 struct irqaction *action, **action_ptr;
1193 unsigned long flags;
1195 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1200 raw_spin_lock_irqsave(&desc->lock, flags);
1203 * There can be multiple actions per IRQ descriptor, find the right
1204 * one based on the dev_id:
1206 action_ptr = &desc->action;
1208 action = *action_ptr;
1211 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1212 raw_spin_unlock_irqrestore(&desc->lock, flags);
1217 if (action->dev_id == dev_id)
1219 action_ptr = &action->next;
1222 /* Found it - now remove it from the list of entries: */
1223 *action_ptr = action->next;
1225 /* If this was the last handler, shut down the IRQ line: */
1230 /* make sure affinity_hint is cleaned up */
1231 if (WARN_ON_ONCE(desc->affinity_hint))
1232 desc->affinity_hint = NULL;
1235 raw_spin_unlock_irqrestore(&desc->lock, flags);
1237 unregister_handler_proc(irq, action);
1239 /* Make sure it's not being used on another CPU: */
1240 synchronize_irq(irq);
1242 #ifdef CONFIG_DEBUG_SHIRQ
1244 * It's a shared IRQ -- the driver ought to be prepared for an IRQ
1245 * event to happen even now it's being freed, so let's make sure that
1246 * is so by doing an extra call to the handler ....
1248 * ( We do this after actually deregistering it, to make sure that a
1249 * 'real' IRQ doesn't run in * parallel with our fake. )
1251 if (action->flags & IRQF_SHARED) {
1252 local_irq_save(flags);
1253 action->handler(irq, dev_id);
1254 local_irq_restore(flags);
1258 if (action->thread) {
1259 kthread_stop(action->thread);
1260 put_task_struct(action->thread);
1263 module_put(desc->owner);
1268 * remove_irq - free an interrupt
1269 * @irq: Interrupt line to free
1270 * @act: irqaction for the interrupt
1272 * Used to remove interrupts statically setup by the early boot process.
1274 void remove_irq(unsigned int irq, struct irqaction *act)
1276 struct irq_desc *desc = irq_to_desc(irq);
1278 if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1279 __free_irq(irq, act->dev_id);
1281 EXPORT_SYMBOL_GPL(remove_irq);
1284 * free_irq - free an interrupt allocated with request_irq
1285 * @irq: Interrupt line to free
1286 * @dev_id: Device identity to free
1288 * Remove an interrupt handler. The handler is removed and if the
1289 * interrupt line is no longer in use by any driver it is disabled.
1290 * On a shared IRQ the caller must ensure the interrupt is disabled
1291 * on the card it drives before calling this function. The function
1292 * does not return until any executing interrupts for this IRQ
1295 * This function must not be called from interrupt context.
1297 void free_irq(unsigned int irq, void *dev_id)
1299 struct irq_desc *desc = irq_to_desc(irq);
1301 if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1305 if (WARN_ON(desc->affinity_notify))
1306 desc->affinity_notify = NULL;
1309 chip_bus_lock(desc);
1310 kfree(__free_irq(irq, dev_id));
1311 chip_bus_sync_unlock(desc);
1313 EXPORT_SYMBOL(free_irq);
1316 * request_threaded_irq - allocate an interrupt line
1317 * @irq: Interrupt line to allocate
1318 * @handler: Function to be called when the IRQ occurs.
1319 * Primary handler for threaded interrupts
1320 * If NULL and thread_fn != NULL the default
1321 * primary handler is installed
1322 * @thread_fn: Function called from the irq handler thread
1323 * If NULL, no irq thread is created
1324 * @irqflags: Interrupt type flags
1325 * @devname: An ascii name for the claiming device
1326 * @dev_id: A cookie passed back to the handler function
1328 * This call allocates interrupt resources and enables the
1329 * interrupt line and IRQ handling. From the point this
1330 * call is made your handler function may be invoked. Since
1331 * your handler function must clear any interrupt the board
1332 * raises, you must take care both to initialise your hardware
1333 * and to set up the interrupt handler in the right order.
1335 * If you want to set up a threaded irq handler for your device
1336 * then you need to supply @handler and @thread_fn. @handler is
1337 * still called in hard interrupt context and has to check
1338 * whether the interrupt originates from the device. If yes it
1339 * needs to disable the interrupt on the device and return
1340 * IRQ_WAKE_THREAD which will wake up the handler thread and run
1341 * @thread_fn. This split handler design is necessary to support
1342 * shared interrupts.
1344 * Dev_id must be globally unique. Normally the address of the
1345 * device data structure is used as the cookie. Since the handler
1346 * receives this value it makes sense to use it.
1348 * If your interrupt is shared you must pass a non NULL dev_id
1349 * as this is required when freeing the interrupt.
1353 * IRQF_SHARED Interrupt is shared
1354 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
1355 * IRQF_TRIGGER_* Specify active edge(s) or level
1358 int request_threaded_irq(unsigned int irq, irq_handler_t handler,
1359 irq_handler_t thread_fn, unsigned long irqflags,
1360 const char *devname, void *dev_id)
1362 struct irqaction *action;
1363 struct irq_desc *desc;
1367 * Sanity-check: shared interrupts must pass in a real dev-ID,
1368 * otherwise we'll have trouble later trying to figure out
1369 * which interrupt is which (messes up the interrupt freeing
1372 if ((irqflags & IRQF_SHARED) && !dev_id)
1375 desc = irq_to_desc(irq);
1379 if (!irq_settings_can_request(desc) ||
1380 WARN_ON(irq_settings_is_per_cpu_devid(desc)))
1386 handler = irq_default_primary_handler;
1389 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1393 action->handler = handler;
1394 action->thread_fn = thread_fn;
1395 action->flags = irqflags;
1396 action->name = devname;
1397 action->dev_id = dev_id;
1399 chip_bus_lock(desc);
1400 retval = __setup_irq(irq, desc, action);
1401 chip_bus_sync_unlock(desc);
1406 #ifdef CONFIG_DEBUG_SHIRQ_FIXME
1407 if (!retval && (irqflags & IRQF_SHARED)) {
1409 * It's a shared IRQ -- the driver ought to be prepared for it
1410 * to happen immediately, so let's make sure....
1411 * We disable the irq to make sure that a 'real' IRQ doesn't
1412 * run in parallel with our fake.
1414 unsigned long flags;
1417 local_irq_save(flags);
1419 handler(irq, dev_id);
1421 local_irq_restore(flags);
1427 EXPORT_SYMBOL(request_threaded_irq);
1430 * request_any_context_irq - allocate an interrupt line
1431 * @irq: Interrupt line to allocate
1432 * @handler: Function to be called when the IRQ occurs.
1433 * Threaded handler for threaded interrupts.
1434 * @flags: Interrupt type flags
1435 * @name: An ascii name for the claiming device
1436 * @dev_id: A cookie passed back to the handler function
1438 * This call allocates interrupt resources and enables the
1439 * interrupt line and IRQ handling. It selects either a
1440 * hardirq or threaded handling method depending on the
1443 * On failure, it returns a negative value. On success,
1444 * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
1446 int request_any_context_irq(unsigned int irq, irq_handler_t handler,
1447 unsigned long flags, const char *name, void *dev_id)
1449 struct irq_desc *desc = irq_to_desc(irq);
1455 if (irq_settings_is_nested_thread(desc)) {
1456 ret = request_threaded_irq(irq, NULL, handler,
1457 flags, name, dev_id);
1458 return !ret ? IRQC_IS_NESTED : ret;
1461 ret = request_irq(irq, handler, flags, name, dev_id);
1462 return !ret ? IRQC_IS_HARDIRQ : ret;
1464 EXPORT_SYMBOL_GPL(request_any_context_irq);
1466 void enable_percpu_irq(unsigned int irq, unsigned int type)
1468 unsigned int cpu = smp_processor_id();
1469 unsigned long flags;
1470 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1475 type &= IRQ_TYPE_SENSE_MASK;
1476 if (type != IRQ_TYPE_NONE) {
1479 ret = __irq_set_trigger(desc, irq, type);
1482 WARN(1, "failed to set type for IRQ%d\n", irq);
1487 irq_percpu_enable(desc, cpu);
1489 irq_put_desc_unlock(desc, flags);
1492 void disable_percpu_irq(unsigned int irq)
1494 unsigned int cpu = smp_processor_id();
1495 unsigned long flags;
1496 struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
1501 irq_percpu_disable(desc, cpu);
1502 irq_put_desc_unlock(desc, flags);
1506 * Internal function to unregister a percpu irqaction.
1508 static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1510 struct irq_desc *desc = irq_to_desc(irq);
1511 struct irqaction *action;
1512 unsigned long flags;
1514 WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
1519 raw_spin_lock_irqsave(&desc->lock, flags);
1521 action = desc->action;
1522 if (!action || action->percpu_dev_id != dev_id) {
1523 WARN(1, "Trying to free already-free IRQ %d\n", irq);
1527 if (!cpumask_empty(desc->percpu_enabled)) {
1528 WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
1529 irq, cpumask_first(desc->percpu_enabled));
1533 /* Found it - now remove it from the list of entries: */
1534 desc->action = NULL;
1536 raw_spin_unlock_irqrestore(&desc->lock, flags);
1538 unregister_handler_proc(irq, action);
1540 module_put(desc->owner);
1544 raw_spin_unlock_irqrestore(&desc->lock, flags);
1549 * remove_percpu_irq - free a per-cpu interrupt
1550 * @irq: Interrupt line to free
1551 * @act: irqaction for the interrupt
1553 * Used to remove interrupts statically setup by the early boot process.
1555 void remove_percpu_irq(unsigned int irq, struct irqaction *act)
1557 struct irq_desc *desc = irq_to_desc(irq);
1559 if (desc && irq_settings_is_per_cpu_devid(desc))
1560 __free_percpu_irq(irq, act->percpu_dev_id);
1564 * free_percpu_irq - free an interrupt allocated with request_percpu_irq
1565 * @irq: Interrupt line to free
1566 * @dev_id: Device identity to free
1568 * Remove a percpu interrupt handler. The handler is removed, but
1569 * the interrupt line is not disabled. This must be done on each
1570 * CPU before calling this function. The function does not return
1571 * until any executing interrupts for this IRQ have completed.
1573 * This function must not be called from interrupt context.
1575 void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
1577 struct irq_desc *desc = irq_to_desc(irq);
1579 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1582 chip_bus_lock(desc);
1583 kfree(__free_percpu_irq(irq, dev_id));
1584 chip_bus_sync_unlock(desc);
1588 * setup_percpu_irq - setup a per-cpu interrupt
1589 * @irq: Interrupt line to setup
1590 * @act: irqaction for the interrupt
1592 * Used to statically setup per-cpu interrupts in the early boot process.
1594 int setup_percpu_irq(unsigned int irq, struct irqaction *act)
1596 struct irq_desc *desc = irq_to_desc(irq);
1599 if (!desc || !irq_settings_is_per_cpu_devid(desc))
1601 chip_bus_lock(desc);
1602 retval = __setup_irq(irq, desc, act);
1603 chip_bus_sync_unlock(desc);
1609 * request_percpu_irq - allocate a percpu interrupt line
1610 * @irq: Interrupt line to allocate
1611 * @handler: Function to be called when the IRQ occurs.
1612 * @devname: An ascii name for the claiming device
1613 * @dev_id: A percpu cookie passed back to the handler function
1615 * This call allocates interrupt resources, but doesn't
1616 * automatically enable the interrupt. It has to be done on each
1617 * CPU using enable_percpu_irq().
1619 * Dev_id must be globally unique. It is a per-cpu variable, and
1620 * the handler gets called with the interrupted CPU's instance of
1623 int request_percpu_irq(unsigned int irq, irq_handler_t handler,
1624 const char *devname, void __percpu *dev_id)
1626 struct irqaction *action;
1627 struct irq_desc *desc;
1633 desc = irq_to_desc(irq);
1634 if (!desc || !irq_settings_can_request(desc) ||
1635 !irq_settings_is_per_cpu_devid(desc))
1638 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
1642 action->handler = handler;
1643 action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
1644 action->name = devname;
1645 action->percpu_dev_id = dev_id;
1647 chip_bus_lock(desc);
1648 retval = __setup_irq(irq, desc, action);
1649 chip_bus_sync_unlock(desc);