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, cpumask_t cpumask)
84 struct irq_desc *desc = irq_to_desc(irq);
86 if (!desc->chip->set_affinity)
89 set_balance_irq_affinity(irq, cpumask);
91 #ifdef CONFIG_GENERIC_PENDING_IRQ
92 if (desc->status & IRQ_MOVE_PCNTXT) {
95 spin_lock_irqsave(&desc->lock, flags);
96 desc->chip->set_affinity(irq, cpumask);
97 spin_unlock_irqrestore(&desc->lock, flags);
99 set_pending_irq(irq, cpumask);
101 desc->affinity = cpumask;
102 desc->chip->set_affinity(irq, cpumask);
107 #ifndef CONFIG_AUTO_IRQ_AFFINITY
109 * Generic version of the affinity autoselector.
111 int irq_select_affinity(unsigned int irq)
114 struct irq_desc *desc;
116 if (!irq_can_set_affinity(irq))
119 cpus_and(mask, cpu_online_map, irq_default_affinity);
121 desc = irq_to_desc(irq);
122 desc->affinity = mask;
123 desc->chip->set_affinity(irq, mask);
125 set_balance_irq_affinity(irq, mask);
133 * disable_irq_nosync - disable an irq without waiting
134 * @irq: Interrupt to disable
136 * Disable the selected interrupt line. Disables and Enables are
138 * Unlike disable_irq(), this function does not ensure existing
139 * instances of the IRQ handler have completed before returning.
141 * This function may be called from IRQ context.
143 void disable_irq_nosync(unsigned int irq)
145 struct irq_desc *desc = irq_to_desc(irq);
151 spin_lock_irqsave(&desc->lock, flags);
152 if (!desc->depth++) {
153 desc->status |= IRQ_DISABLED;
154 desc->chip->disable(irq);
156 spin_unlock_irqrestore(&desc->lock, flags);
158 EXPORT_SYMBOL(disable_irq_nosync);
161 * disable_irq - disable an irq and wait for completion
162 * @irq: Interrupt to disable
164 * Disable the selected interrupt line. Enables and Disables are
166 * This function waits for any pending IRQ handlers for this interrupt
167 * to complete before returning. If you use this function while
168 * holding a resource the IRQ handler may need you will deadlock.
170 * This function may be called - with care - from IRQ context.
172 void disable_irq(unsigned int irq)
174 struct irq_desc *desc = irq_to_desc(irq);
179 disable_irq_nosync(irq);
181 synchronize_irq(irq);
183 EXPORT_SYMBOL(disable_irq);
185 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
187 switch (desc->depth) {
189 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
192 unsigned int status = desc->status & ~IRQ_DISABLED;
194 /* Prevent probing on this irq: */
195 desc->status = status | IRQ_NOPROBE;
196 check_irq_resend(desc, irq);
205 * enable_irq - enable handling of an irq
206 * @irq: Interrupt to enable
208 * Undoes the effect of one call to disable_irq(). If this
209 * matches the last disable, processing of interrupts on this
210 * IRQ line is re-enabled.
212 * This function may be called from IRQ context.
214 void enable_irq(unsigned int irq)
216 struct irq_desc *desc = irq_to_desc(irq);
222 spin_lock_irqsave(&desc->lock, flags);
223 __enable_irq(desc, irq);
224 spin_unlock_irqrestore(&desc->lock, flags);
226 EXPORT_SYMBOL(enable_irq);
228 static int set_irq_wake_real(unsigned int irq, unsigned int on)
230 struct irq_desc *desc = irq_to_desc(irq);
233 if (desc->chip->set_wake)
234 ret = desc->chip->set_wake(irq, on);
240 * set_irq_wake - control irq power management wakeup
241 * @irq: interrupt to control
242 * @on: enable/disable power management wakeup
244 * Enable/disable power management wakeup mode, which is
245 * disabled by default. Enables and disables must match,
246 * just as they match for non-wakeup mode support.
248 * Wakeup mode lets this IRQ wake the system from sleep
249 * states like "suspend to RAM".
251 int set_irq_wake(unsigned int irq, unsigned int on)
253 struct irq_desc *desc = irq_to_desc(irq);
257 /* wakeup-capable irqs can be shared between drivers that
258 * don't need to have the same sleep mode behaviors.
260 spin_lock_irqsave(&desc->lock, flags);
262 if (desc->wake_depth++ == 0) {
263 ret = set_irq_wake_real(irq, on);
265 desc->wake_depth = 0;
267 desc->status |= IRQ_WAKEUP;
270 if (desc->wake_depth == 0) {
271 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
272 } else if (--desc->wake_depth == 0) {
273 ret = set_irq_wake_real(irq, on);
275 desc->wake_depth = 1;
277 desc->status &= ~IRQ_WAKEUP;
281 spin_unlock_irqrestore(&desc->lock, flags);
284 EXPORT_SYMBOL(set_irq_wake);
287 * Internal function that tells the architecture code whether a
288 * particular irq has been exclusively allocated or is available
291 int can_request_irq(unsigned int irq, unsigned long irqflags)
293 struct irq_desc *desc = irq_to_desc(irq);
294 struct irqaction *action;
296 if (irq >= nr_irqs || desc->status & IRQ_NOREQUEST)
299 action = desc->action;
301 if (irqflags & action->flags & IRQF_SHARED)
307 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
310 * If the architecture still has not overriden
311 * the flow handler then zap the default. This
312 * should catch incorrect flow-type setting.
314 if (desc->handle_irq == &handle_bad_irq)
315 desc->handle_irq = NULL;
318 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
322 struct irq_chip *chip = desc->chip;
324 if (!chip || !chip->set_type) {
326 * IRQF_TRIGGER_* but the PIC does not support multiple
329 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
330 chip ? (chip->name ? : "unknown") : "unknown");
334 ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
337 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
338 (int)(flags & IRQF_TRIGGER_MASK),
339 irq, chip->set_type);
341 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
342 desc->status &= ~IRQ_TYPE_SENSE_MASK;
343 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
350 * Internal function to register an irqaction - typically used to
351 * allocate special interrupts that are part of the architecture.
353 int setup_irq(unsigned int irq, struct irqaction *new)
355 struct irq_desc *desc = irq_to_desc(irq);
356 struct irqaction *old, **p;
357 const char *old_name = NULL;
365 if (desc->chip == &no_irq_chip)
368 * Some drivers like serial.c use request_irq() heavily,
369 * so we have to be careful not to interfere with a
372 if (new->flags & IRQF_SAMPLE_RANDOM) {
374 * This function might sleep, we want to call it first,
375 * outside of the atomic block.
376 * Yes, this might clear the entropy pool if the wrong
377 * driver is attempted to be loaded, without actually
378 * installing a new handler, but is this really a problem,
379 * only the sysadmin is able to do this.
381 rand_initialize_irq(irq);
385 * The following block of code has to be executed atomically
387 spin_lock_irqsave(&desc->lock, flags);
392 * Can't share interrupts unless both agree to and are
393 * the same type (level, edge, polarity). So both flag
394 * fields must have IRQF_SHARED set and the bits which
395 * set the trigger type must match.
397 if (!((old->flags & new->flags) & IRQF_SHARED) ||
398 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
399 old_name = old->name;
403 #if defined(CONFIG_IRQ_PER_CPU)
404 /* All handlers must agree on per-cpuness */
405 if ((old->flags & IRQF_PERCPU) !=
406 (new->flags & IRQF_PERCPU))
410 /* add new interrupt at end of irq queue */
419 irq_chip_set_defaults(desc->chip);
421 /* Setup the type (level, edge polarity) if configured: */
422 if (new->flags & IRQF_TRIGGER_MASK) {
423 ret = __irq_set_trigger(desc, irq, new->flags);
426 spin_unlock_irqrestore(&desc->lock, flags);
430 compat_irq_chip_set_default_handler(desc);
431 #if defined(CONFIG_IRQ_PER_CPU)
432 if (new->flags & IRQF_PERCPU)
433 desc->status |= IRQ_PER_CPU;
436 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
437 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
439 if (!(desc->status & IRQ_NOAUTOEN)) {
441 desc->status &= ~IRQ_DISABLED;
442 desc->chip->startup(irq);
444 /* Undo nested disables: */
447 /* Set default affinity mask once everything is setup */
448 irq_select_affinity(irq);
450 } else if ((new->flags & IRQF_TRIGGER_MASK)
451 && (new->flags & IRQF_TRIGGER_MASK)
452 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
453 /* hope the handler works with the actual trigger mode... */
454 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
455 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
456 (int)(new->flags & IRQF_TRIGGER_MASK));
461 /* Exclude IRQ from balancing */
462 if (new->flags & IRQF_NOBALANCING)
463 desc->status |= IRQ_NO_BALANCING;
465 /* Reset broken irq detection when installing new handler */
467 desc->irqs_unhandled = 0;
470 * Check whether we disabled the irq via the spurious handler
471 * before. Reenable it and give it another chance.
473 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
474 desc->status &= ~IRQ_SPURIOUS_DISABLED;
475 __enable_irq(desc, irq);
478 spin_unlock_irqrestore(&desc->lock, flags);
481 register_irq_proc(irq);
483 register_handler_proc(irq, new);
488 #ifdef CONFIG_DEBUG_SHIRQ
489 if (!(new->flags & IRQF_PROBE_SHARED)) {
490 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
492 printk(KERN_ERR "current handler: %s\n", old_name);
496 spin_unlock_irqrestore(&desc->lock, flags);
501 * free_irq - free an interrupt
502 * @irq: Interrupt line to free
503 * @dev_id: Device identity to free
505 * Remove an interrupt handler. The handler is removed and if the
506 * interrupt line is no longer in use by any driver it is disabled.
507 * On a shared IRQ the caller must ensure the interrupt is disabled
508 * on the card it drives before calling this function. The function
509 * does not return until any executing interrupts for this IRQ
512 * This function must not be called from interrupt context.
514 void free_irq(unsigned int irq, void *dev_id)
516 struct irq_desc *desc;
517 struct irqaction **p;
520 WARN_ON(in_interrupt());
524 desc = irq_to_desc(irq);
525 spin_lock_irqsave(&desc->lock, flags);
528 struct irqaction *action = *p;
531 struct irqaction **pp = p;
534 if (action->dev_id != dev_id)
537 /* Found it - now remove it from the list of entries */
540 /* Currently used only by UML, might disappear one day.*/
541 #ifdef CONFIG_IRQ_RELEASE_METHOD
542 if (desc->chip->release)
543 desc->chip->release(irq, dev_id);
547 desc->status |= IRQ_DISABLED;
548 if (desc->chip->shutdown)
549 desc->chip->shutdown(irq);
551 desc->chip->disable(irq);
553 spin_unlock_irqrestore(&desc->lock, flags);
554 unregister_handler_proc(irq, action);
556 /* Make sure it's not being used on another CPU */
557 synchronize_irq(irq);
558 #ifdef CONFIG_DEBUG_SHIRQ
560 * It's a shared IRQ -- the driver ought to be
561 * prepared for it to happen even now it's
562 * being freed, so let's make sure.... We do
563 * this after actually deregistering it, to
564 * make sure that a 'real' IRQ doesn't run in
565 * parallel with our fake
567 if (action->flags & IRQF_SHARED) {
568 local_irq_save(flags);
569 action->handler(irq, dev_id);
570 local_irq_restore(flags);
576 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
577 #ifdef CONFIG_DEBUG_SHIRQ
580 spin_unlock_irqrestore(&desc->lock, flags);
584 EXPORT_SYMBOL(free_irq);
587 * request_irq - allocate an interrupt line
588 * @irq: Interrupt line to allocate
589 * @handler: Function to be called when the IRQ occurs
590 * @irqflags: Interrupt type flags
591 * @devname: An ascii name for the claiming device
592 * @dev_id: A cookie passed back to the handler function
594 * This call allocates interrupt resources and enables the
595 * interrupt line and IRQ handling. From the point this
596 * call is made your handler function may be invoked. Since
597 * your handler function must clear any interrupt the board
598 * raises, you must take care both to initialise your hardware
599 * and to set up the interrupt handler in the right order.
601 * Dev_id must be globally unique. Normally the address of the
602 * device data structure is used as the cookie. Since the handler
603 * receives this value it makes sense to use it.
605 * If your interrupt is shared you must pass a non NULL dev_id
606 * as this is required when freeing the interrupt.
610 * IRQF_SHARED Interrupt is shared
611 * IRQF_DISABLED Disable local interrupts while processing
612 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
613 * IRQF_TRIGGER_* Specify active edge(s) or level
616 int request_irq(unsigned int irq, irq_handler_t handler,
617 unsigned long irqflags, const char *devname, void *dev_id)
619 struct irqaction *action;
621 struct irq_desc *desc;
623 #ifdef CONFIG_LOCKDEP
625 * Lockdep wants atomic interrupt handlers:
627 irqflags |= IRQF_DISABLED;
630 * Sanity-check: shared interrupts must pass in a real dev-ID,
631 * otherwise we'll have trouble later trying to figure out
632 * which interrupt is which (messes up the interrupt freeing
635 if ((irqflags & IRQF_SHARED) && !dev_id)
639 desc = irq_to_desc(irq);
640 if (desc->status & IRQ_NOREQUEST)
645 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
649 action->handler = handler;
650 action->flags = irqflags;
651 cpus_clear(action->mask);
652 action->name = devname;
654 action->dev_id = dev_id;
656 retval = setup_irq(irq, action);
660 #ifdef CONFIG_DEBUG_SHIRQ
661 if (irqflags & IRQF_SHARED) {
663 * It's a shared IRQ -- the driver ought to be prepared for it
664 * to happen immediately, so let's make sure....
665 * We disable the irq to make sure that a 'real' IRQ doesn't
666 * run in parallel with our fake.
671 local_irq_save(flags);
673 handler(irq, dev_id);
675 local_irq_restore(flags);
681 EXPORT_SYMBOL(request_irq);