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/module.h>
12 #include <linux/random.h>
13 #include <linux/interrupt.h>
14 #include <linux/slab.h>
16 #include "internals.h"
20 cpumask_t irq_default_affinity = CPU_MASK_ALL;
23 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
24 * @irq: interrupt number to wait for
26 * This function waits for any pending IRQ handlers for this interrupt
27 * to complete before returning. If you use this function while
28 * holding a resource the IRQ handler may need you will deadlock.
30 * This function may be called - with care - from IRQ context.
32 void synchronize_irq(unsigned int irq)
34 struct irq_desc *desc = irq_to_desc(irq);
44 * Wait until we're out of the critical section. This might
45 * give the wrong answer due to the lack of memory barriers.
47 while (desc->status & IRQ_INPROGRESS)
50 /* Ok, that indicated we're done: double-check carefully. */
51 spin_lock_irqsave(&desc->lock, flags);
52 status = desc->status;
53 spin_unlock_irqrestore(&desc->lock, flags);
55 /* Oops, that failed? */
56 } while (status & IRQ_INPROGRESS);
58 EXPORT_SYMBOL(synchronize_irq);
61 * irq_can_set_affinity - Check if the affinity of a given irq can be set
62 * @irq: Interrupt to check
65 int irq_can_set_affinity(unsigned int irq)
67 struct irq_desc *desc = irq_to_desc(irq);
69 if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
70 !desc->chip->set_affinity)
77 * irq_set_affinity - Set the irq affinity of a given irq
78 * @irq: Interrupt to set affinity
82 int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
84 struct irq_desc *desc = irq_to_desc(irq);
87 if (!desc->chip->set_affinity)
90 spin_lock_irqsave(&desc->lock, flags);
92 #ifdef CONFIG_GENERIC_PENDING_IRQ
93 if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) {
94 cpumask_copy(&desc->affinity, cpumask);
95 desc->chip->set_affinity(irq, cpumask);
97 desc->status |= IRQ_MOVE_PENDING;
98 cpumask_copy(&desc->pending_mask, cpumask);
101 cpumask_copy(&desc->affinity, cpumask);
102 desc->chip->set_affinity(irq, cpumask);
104 desc->status |= IRQ_AFFINITY_SET;
105 spin_unlock_irqrestore(&desc->lock, flags);
109 #ifndef CONFIG_AUTO_IRQ_AFFINITY
111 * Generic version of the affinity autoselector.
113 int do_irq_select_affinity(unsigned int irq, struct irq_desc *desc)
115 if (!irq_can_set_affinity(irq))
119 * Preserve an userspace affinity setup, but make sure that
120 * one of the targets is online.
122 if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
123 if (cpumask_any_and(&desc->affinity, cpu_online_mask)
127 desc->status &= ~IRQ_AFFINITY_SET;
130 cpumask_and(&desc->affinity, cpu_online_mask, &irq_default_affinity);
132 desc->chip->set_affinity(irq, &desc->affinity);
137 static inline int do_irq_select_affinity(unsigned int irq, struct irq_desc *d)
139 return irq_select_affinity(irq);
144 * Called when affinity is set via /proc/irq
146 int irq_select_affinity_usr(unsigned int irq)
148 struct irq_desc *desc = irq_to_desc(irq);
152 spin_lock_irqsave(&desc->lock, flags);
153 ret = do_irq_select_affinity(irq, desc);
154 spin_unlock_irqrestore(&desc->lock, flags);
160 static inline int do_irq_select_affinity(int irq, struct irq_desc *desc)
167 * disable_irq_nosync - disable an irq without waiting
168 * @irq: Interrupt to disable
170 * Disable the selected interrupt line. Disables and Enables are
172 * Unlike disable_irq(), this function does not ensure existing
173 * instances of the IRQ handler have completed before returning.
175 * This function may be called from IRQ context.
177 void disable_irq_nosync(unsigned int irq)
179 struct irq_desc *desc = irq_to_desc(irq);
185 spin_lock_irqsave(&desc->lock, flags);
186 if (!desc->depth++) {
187 desc->status |= IRQ_DISABLED;
188 desc->chip->disable(irq);
190 spin_unlock_irqrestore(&desc->lock, flags);
192 EXPORT_SYMBOL(disable_irq_nosync);
195 * disable_irq - disable an irq and wait for completion
196 * @irq: Interrupt to disable
198 * Disable the selected interrupt line. Enables and Disables are
200 * This function waits for any pending IRQ handlers for this interrupt
201 * to complete before returning. If you use this function while
202 * holding a resource the IRQ handler may need you will deadlock.
204 * This function may be called - with care - from IRQ context.
206 void disable_irq(unsigned int irq)
208 struct irq_desc *desc = irq_to_desc(irq);
213 disable_irq_nosync(irq);
215 synchronize_irq(irq);
217 EXPORT_SYMBOL(disable_irq);
219 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
221 switch (desc->depth) {
223 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
226 unsigned int status = desc->status & ~IRQ_DISABLED;
228 /* Prevent probing on this irq: */
229 desc->status = status | IRQ_NOPROBE;
230 check_irq_resend(desc, irq);
239 * enable_irq - enable handling of an irq
240 * @irq: Interrupt to enable
242 * Undoes the effect of one call to disable_irq(). If this
243 * matches the last disable, processing of interrupts on this
244 * IRQ line is re-enabled.
246 * This function may be called from IRQ context.
248 void enable_irq(unsigned int irq)
250 struct irq_desc *desc = irq_to_desc(irq);
256 spin_lock_irqsave(&desc->lock, flags);
257 __enable_irq(desc, irq);
258 spin_unlock_irqrestore(&desc->lock, flags);
260 EXPORT_SYMBOL(enable_irq);
262 static int set_irq_wake_real(unsigned int irq, unsigned int on)
264 struct irq_desc *desc = irq_to_desc(irq);
267 if (desc->chip->set_wake)
268 ret = desc->chip->set_wake(irq, on);
274 * set_irq_wake - control irq power management wakeup
275 * @irq: interrupt to control
276 * @on: enable/disable power management wakeup
278 * Enable/disable power management wakeup mode, which is
279 * disabled by default. Enables and disables must match,
280 * just as they match for non-wakeup mode support.
282 * Wakeup mode lets this IRQ wake the system from sleep
283 * states like "suspend to RAM".
285 int set_irq_wake(unsigned int irq, unsigned int on)
287 struct irq_desc *desc = irq_to_desc(irq);
291 /* wakeup-capable irqs can be shared between drivers that
292 * don't need to have the same sleep mode behaviors.
294 spin_lock_irqsave(&desc->lock, flags);
296 if (desc->wake_depth++ == 0) {
297 ret = set_irq_wake_real(irq, on);
299 desc->wake_depth = 0;
301 desc->status |= IRQ_WAKEUP;
304 if (desc->wake_depth == 0) {
305 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
306 } else if (--desc->wake_depth == 0) {
307 ret = set_irq_wake_real(irq, on);
309 desc->wake_depth = 1;
311 desc->status &= ~IRQ_WAKEUP;
315 spin_unlock_irqrestore(&desc->lock, flags);
318 EXPORT_SYMBOL(set_irq_wake);
321 * Internal function that tells the architecture code whether a
322 * particular irq has been exclusively allocated or is available
325 int can_request_irq(unsigned int irq, unsigned long irqflags)
327 struct irq_desc *desc = irq_to_desc(irq);
328 struct irqaction *action;
333 if (desc->status & IRQ_NOREQUEST)
336 action = desc->action;
338 if (irqflags & action->flags & IRQF_SHARED)
344 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
347 * If the architecture still has not overriden
348 * the flow handler then zap the default. This
349 * should catch incorrect flow-type setting.
351 if (desc->handle_irq == &handle_bad_irq)
352 desc->handle_irq = NULL;
355 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
359 struct irq_chip *chip = desc->chip;
361 if (!chip || !chip->set_type) {
363 * IRQF_TRIGGER_* but the PIC does not support multiple
366 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
367 chip ? (chip->name ? : "unknown") : "unknown");
371 /* caller masked out all except trigger mode flags */
372 ret = chip->set_type(irq, flags);
375 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
376 (int)flags, irq, chip->set_type);
378 if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
380 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
381 desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
382 desc->status |= flags;
389 * Internal function to register an irqaction - typically used to
390 * allocate special interrupts that are part of the architecture.
393 __setup_irq(unsigned int irq, struct irq_desc * desc, struct irqaction *new)
395 struct irqaction *old, **p;
396 const char *old_name = NULL;
404 if (desc->chip == &no_irq_chip)
407 * Some drivers like serial.c use request_irq() heavily,
408 * so we have to be careful not to interfere with a
411 if (new->flags & IRQF_SAMPLE_RANDOM) {
413 * This function might sleep, we want to call it first,
414 * outside of the atomic block.
415 * Yes, this might clear the entropy pool if the wrong
416 * driver is attempted to be loaded, without actually
417 * installing a new handler, but is this really a problem,
418 * only the sysadmin is able to do this.
420 rand_initialize_irq(irq);
424 * The following block of code has to be executed atomically
426 spin_lock_irqsave(&desc->lock, flags);
431 * Can't share interrupts unless both agree to and are
432 * the same type (level, edge, polarity). So both flag
433 * fields must have IRQF_SHARED set and the bits which
434 * set the trigger type must match.
436 if (!((old->flags & new->flags) & IRQF_SHARED) ||
437 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
438 old_name = old->name;
442 #if defined(CONFIG_IRQ_PER_CPU)
443 /* All handlers must agree on per-cpuness */
444 if ((old->flags & IRQF_PERCPU) !=
445 (new->flags & IRQF_PERCPU))
449 /* add new interrupt at end of irq queue */
458 irq_chip_set_defaults(desc->chip);
460 /* Setup the type (level, edge polarity) if configured: */
461 if (new->flags & IRQF_TRIGGER_MASK) {
462 ret = __irq_set_trigger(desc, irq,
463 new->flags & IRQF_TRIGGER_MASK);
466 spin_unlock_irqrestore(&desc->lock, flags);
470 compat_irq_chip_set_default_handler(desc);
471 #if defined(CONFIG_IRQ_PER_CPU)
472 if (new->flags & IRQF_PERCPU)
473 desc->status |= IRQ_PER_CPU;
476 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
477 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
479 if (!(desc->status & IRQ_NOAUTOEN)) {
481 desc->status &= ~IRQ_DISABLED;
482 desc->chip->startup(irq);
484 /* Undo nested disables: */
487 /* Exclude IRQ from balancing if requested */
488 if (new->flags & IRQF_NOBALANCING)
489 desc->status |= IRQ_NO_BALANCING;
491 /* Set default affinity mask once everything is setup */
492 do_irq_select_affinity(irq, desc);
494 } else if ((new->flags & IRQF_TRIGGER_MASK)
495 && (new->flags & IRQF_TRIGGER_MASK)
496 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
497 /* hope the handler works with the actual trigger mode... */
498 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
499 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
500 (int)(new->flags & IRQF_TRIGGER_MASK));
505 /* Reset broken irq detection when installing new handler */
507 desc->irqs_unhandled = 0;
510 * Check whether we disabled the irq via the spurious handler
511 * before. Reenable it and give it another chance.
513 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
514 desc->status &= ~IRQ_SPURIOUS_DISABLED;
515 __enable_irq(desc, irq);
518 spin_unlock_irqrestore(&desc->lock, flags);
521 register_irq_proc(irq, desc);
523 register_handler_proc(irq, new);
528 #ifdef CONFIG_DEBUG_SHIRQ
529 if (!(new->flags & IRQF_PROBE_SHARED)) {
530 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
532 printk(KERN_ERR "current handler: %s\n", old_name);
536 spin_unlock_irqrestore(&desc->lock, flags);
541 * setup_irq - setup an interrupt
542 * @irq: Interrupt line to setup
543 * @act: irqaction for the interrupt
545 * Used to statically setup interrupts in the early boot process.
547 int setup_irq(unsigned int irq, struct irqaction *act)
549 struct irq_desc *desc = irq_to_desc(irq);
551 return __setup_irq(irq, desc, act);
555 * free_irq - free an interrupt
556 * @irq: Interrupt line to free
557 * @dev_id: Device identity to free
559 * Remove an interrupt handler. The handler is removed and if the
560 * interrupt line is no longer in use by any driver it is disabled.
561 * On a shared IRQ the caller must ensure the interrupt is disabled
562 * on the card it drives before calling this function. The function
563 * does not return until any executing interrupts for this IRQ
566 * This function must not be called from interrupt context.
568 void free_irq(unsigned int irq, void *dev_id)
570 struct irq_desc *desc = irq_to_desc(irq);
571 struct irqaction **p;
574 WARN_ON(in_interrupt());
579 spin_lock_irqsave(&desc->lock, flags);
582 struct irqaction *action = *p;
585 struct irqaction **pp = p;
588 if (action->dev_id != dev_id)
591 /* Found it - now remove it from the list of entries */
594 /* Currently used only by UML, might disappear one day.*/
595 #ifdef CONFIG_IRQ_RELEASE_METHOD
596 if (desc->chip->release)
597 desc->chip->release(irq, dev_id);
601 desc->status |= IRQ_DISABLED;
602 if (desc->chip->shutdown)
603 desc->chip->shutdown(irq);
605 desc->chip->disable(irq);
607 spin_unlock_irqrestore(&desc->lock, flags);
608 unregister_handler_proc(irq, action);
610 /* Make sure it's not being used on another CPU */
611 synchronize_irq(irq);
612 #ifdef CONFIG_DEBUG_SHIRQ
614 * It's a shared IRQ -- the driver ought to be
615 * prepared for it to happen even now it's
616 * being freed, so let's make sure.... We do
617 * this after actually deregistering it, to
618 * make sure that a 'real' IRQ doesn't run in
619 * parallel with our fake
621 if (action->flags & IRQF_SHARED) {
622 local_irq_save(flags);
623 action->handler(irq, dev_id);
624 local_irq_restore(flags);
630 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
631 #ifdef CONFIG_DEBUG_SHIRQ
634 spin_unlock_irqrestore(&desc->lock, flags);
638 EXPORT_SYMBOL(free_irq);
641 * request_irq - allocate an interrupt line
642 * @irq: Interrupt line to allocate
643 * @handler: Function to be called when the IRQ occurs
644 * @irqflags: Interrupt type flags
645 * @devname: An ascii name for the claiming device
646 * @dev_id: A cookie passed back to the handler function
648 * This call allocates interrupt resources and enables the
649 * interrupt line and IRQ handling. From the point this
650 * call is made your handler function may be invoked. Since
651 * your handler function must clear any interrupt the board
652 * raises, you must take care both to initialise your hardware
653 * and to set up the interrupt handler in the right order.
655 * Dev_id must be globally unique. Normally the address of the
656 * device data structure is used as the cookie. Since the handler
657 * receives this value it makes sense to use it.
659 * If your interrupt is shared you must pass a non NULL dev_id
660 * as this is required when freeing the interrupt.
664 * IRQF_SHARED Interrupt is shared
665 * IRQF_DISABLED Disable local interrupts while processing
666 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
667 * IRQF_TRIGGER_* Specify active edge(s) or level
670 int request_irq(unsigned int irq, irq_handler_t handler,
671 unsigned long irqflags, const char *devname, void *dev_id)
673 struct irqaction *action;
674 struct irq_desc *desc;
678 * handle_IRQ_event() always ignores IRQF_DISABLED except for
679 * the _first_ irqaction (sigh). That can cause oopsing, but
680 * the behavior is classified as "will not fix" so we need to
681 * start nudging drivers away from using that idiom.
683 if ((irqflags & (IRQF_SHARED|IRQF_DISABLED))
684 == (IRQF_SHARED|IRQF_DISABLED))
685 pr_warning("IRQ %d/%s: IRQF_DISABLED is not "
686 "guaranteed on shared IRQs\n",
689 #ifdef CONFIG_LOCKDEP
691 * Lockdep wants atomic interrupt handlers:
693 irqflags |= IRQF_DISABLED;
696 * Sanity-check: shared interrupts must pass in a real dev-ID,
697 * otherwise we'll have trouble later trying to figure out
698 * which interrupt is which (messes up the interrupt freeing
701 if ((irqflags & IRQF_SHARED) && !dev_id)
704 desc = irq_to_desc(irq);
708 if (desc->status & IRQ_NOREQUEST)
713 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
717 action->handler = handler;
718 action->flags = irqflags;
719 cpus_clear(action->mask);
720 action->name = devname;
722 action->dev_id = dev_id;
724 retval = __setup_irq(irq, desc, action);
728 #ifdef CONFIG_DEBUG_SHIRQ
729 if (irqflags & IRQF_SHARED) {
731 * It's a shared IRQ -- the driver ought to be prepared for it
732 * to happen immediately, so let's make sure....
733 * We disable the irq to make sure that a 'real' IRQ doesn't
734 * run in parallel with our fake.
739 local_irq_save(flags);
741 handler(irq, dev_id);
743 local_irq_restore(flags);
749 EXPORT_SYMBOL(request_irq);