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 #ifdef CONFIG_GENERIC_PENDING_IRQ
90 if (desc->status & IRQ_MOVE_PCNTXT) {
93 spin_lock_irqsave(&desc->lock, flags);
94 desc->chip->set_affinity(irq, cpumask);
95 spin_unlock_irqrestore(&desc->lock, flags);
97 set_pending_irq(irq, cpumask);
99 desc->affinity = cpumask;
100 desc->chip->set_affinity(irq, cpumask);
105 #ifndef CONFIG_AUTO_IRQ_AFFINITY
107 * Generic version of the affinity autoselector.
109 int irq_select_affinity(unsigned int irq)
112 struct irq_desc *desc;
114 if (!irq_can_set_affinity(irq))
117 cpus_and(mask, cpu_online_map, irq_default_affinity);
119 desc = irq_to_desc(irq);
120 desc->affinity = mask;
121 desc->chip->set_affinity(irq, mask);
130 * disable_irq_nosync - disable an irq without waiting
131 * @irq: Interrupt to disable
133 * Disable the selected interrupt line. Disables and Enables are
135 * Unlike disable_irq(), this function does not ensure existing
136 * instances of the IRQ handler have completed before returning.
138 * This function may be called from IRQ context.
140 void disable_irq_nosync(unsigned int irq)
142 struct irq_desc *desc;
145 desc = irq_to_desc(irq);
149 spin_lock_irqsave(&desc->lock, flags);
150 if (!desc->depth++) {
151 desc->status |= IRQ_DISABLED;
152 desc->chip->disable(irq);
154 spin_unlock_irqrestore(&desc->lock, flags);
156 EXPORT_SYMBOL(disable_irq_nosync);
159 * disable_irq - disable an irq and wait for completion
160 * @irq: Interrupt to disable
162 * Disable the selected interrupt line. Enables and Disables are
164 * This function waits for any pending IRQ handlers for this interrupt
165 * to complete before returning. If you use this function while
166 * holding a resource the IRQ handler may need you will deadlock.
168 * This function may be called - with care - from IRQ context.
170 void disable_irq(unsigned int irq)
172 struct irq_desc *desc;
174 desc = irq_to_desc(irq);
178 disable_irq_nosync(irq);
180 synchronize_irq(irq);
182 EXPORT_SYMBOL(disable_irq);
184 static void __enable_irq(struct irq_desc *desc, unsigned int irq)
186 switch (desc->depth) {
188 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
191 unsigned int status = desc->status & ~IRQ_DISABLED;
193 /* Prevent probing on this irq: */
194 desc->status = status | IRQ_NOPROBE;
195 check_irq_resend(desc, irq);
204 * enable_irq - enable handling of an irq
205 * @irq: Interrupt to enable
207 * Undoes the effect of one call to disable_irq(). If this
208 * matches the last disable, processing of interrupts on this
209 * IRQ line is re-enabled.
211 * This function may be called from IRQ context.
213 void enable_irq(unsigned int irq)
215 struct irq_desc *desc;
218 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;
294 struct irqaction *action;
296 desc = irq_to_desc(irq);
300 if (desc->status & IRQ_NOREQUEST)
303 action = desc->action;
305 if (irqflags & action->flags & IRQF_SHARED)
311 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
314 * If the architecture still has not overriden
315 * the flow handler then zap the default. This
316 * should catch incorrect flow-type setting.
318 if (desc->handle_irq == &handle_bad_irq)
319 desc->handle_irq = NULL;
322 int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
326 struct irq_chip *chip = desc->chip;
328 if (!chip || !chip->set_type) {
330 * IRQF_TRIGGER_* but the PIC does not support multiple
333 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
334 chip ? (chip->name ? : "unknown") : "unknown");
338 ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
341 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
342 (int)(flags & IRQF_TRIGGER_MASK),
343 irq, chip->set_type);
345 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
346 desc->status &= ~IRQ_TYPE_SENSE_MASK;
347 desc->status |= flags & IRQ_TYPE_SENSE_MASK;
354 * Internal function to register an irqaction - typically used to
355 * allocate special interrupts that are part of the architecture.
357 int setup_irq(unsigned int irq, struct irqaction *new)
359 struct irq_desc *desc;
360 struct irqaction *old, **p;
361 const char *old_name = NULL;
366 desc = irq_to_desc(irq);
370 if (desc->chip == &no_irq_chip)
373 * Some drivers like serial.c use request_irq() heavily,
374 * so we have to be careful not to interfere with a
377 if (new->flags & IRQF_SAMPLE_RANDOM) {
379 * This function might sleep, we want to call it first,
380 * outside of the atomic block.
381 * Yes, this might clear the entropy pool if the wrong
382 * driver is attempted to be loaded, without actually
383 * installing a new handler, but is this really a problem,
384 * only the sysadmin is able to do this.
386 rand_initialize_irq(irq);
390 * The following block of code has to be executed atomically
392 spin_lock_irqsave(&desc->lock, flags);
397 * Can't share interrupts unless both agree to and are
398 * the same type (level, edge, polarity). So both flag
399 * fields must have IRQF_SHARED set and the bits which
400 * set the trigger type must match.
402 if (!((old->flags & new->flags) & IRQF_SHARED) ||
403 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
404 old_name = old->name;
408 #if defined(CONFIG_IRQ_PER_CPU)
409 /* All handlers must agree on per-cpuness */
410 if ((old->flags & IRQF_PERCPU) !=
411 (new->flags & IRQF_PERCPU))
415 /* add new interrupt at end of irq queue */
424 irq_chip_set_defaults(desc->chip);
426 /* Setup the type (level, edge polarity) if configured: */
427 if (new->flags & IRQF_TRIGGER_MASK) {
428 ret = __irq_set_trigger(desc, irq, new->flags);
431 spin_unlock_irqrestore(&desc->lock, flags);
435 compat_irq_chip_set_default_handler(desc);
436 #if defined(CONFIG_IRQ_PER_CPU)
437 if (new->flags & IRQF_PERCPU)
438 desc->status |= IRQ_PER_CPU;
441 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
442 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
444 if (!(desc->status & IRQ_NOAUTOEN)) {
446 desc->status &= ~IRQ_DISABLED;
447 desc->chip->startup(irq);
449 /* Undo nested disables: */
452 /* Set default affinity mask once everything is setup */
453 irq_select_affinity(irq);
455 } else if ((new->flags & IRQF_TRIGGER_MASK)
456 && (new->flags & IRQF_TRIGGER_MASK)
457 != (desc->status & IRQ_TYPE_SENSE_MASK)) {
458 /* hope the handler works with the actual trigger mode... */
459 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
460 irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
461 (int)(new->flags & IRQF_TRIGGER_MASK));
466 /* Exclude IRQ from balancing */
467 if (new->flags & IRQF_NOBALANCING)
468 desc->status |= IRQ_NO_BALANCING;
470 /* Reset broken irq detection when installing new handler */
472 desc->irqs_unhandled = 0;
475 * Check whether we disabled the irq via the spurious handler
476 * before. Reenable it and give it another chance.
478 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
479 desc->status &= ~IRQ_SPURIOUS_DISABLED;
480 __enable_irq(desc, irq);
483 spin_unlock_irqrestore(&desc->lock, flags);
486 register_irq_proc(irq, desc);
488 register_handler_proc(irq, new);
493 #ifdef CONFIG_DEBUG_SHIRQ
494 if (!(new->flags & IRQF_PROBE_SHARED)) {
495 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
497 printk(KERN_ERR "current handler: %s\n", old_name);
501 spin_unlock_irqrestore(&desc->lock, flags);
506 * free_irq - free an interrupt
507 * @irq: Interrupt line to free
508 * @dev_id: Device identity to free
510 * Remove an interrupt handler. The handler is removed and if the
511 * interrupt line is no longer in use by any driver it is disabled.
512 * On a shared IRQ the caller must ensure the interrupt is disabled
513 * on the card it drives before calling this function. The function
514 * does not return until any executing interrupts for this IRQ
517 * This function must not be called from interrupt context.
519 void free_irq(unsigned int irq, void *dev_id)
521 struct irq_desc *desc;
522 struct irqaction **p;
525 WARN_ON(in_interrupt());
527 desc = irq_to_desc(irq);
531 spin_lock_irqsave(&desc->lock, flags);
534 struct irqaction *action = *p;
537 struct irqaction **pp = p;
540 if (action->dev_id != dev_id)
543 /* Found it - now remove it from the list of entries */
546 /* Currently used only by UML, might disappear one day.*/
547 #ifdef CONFIG_IRQ_RELEASE_METHOD
548 if (desc->chip->release)
549 desc->chip->release(irq, dev_id);
553 desc->status |= IRQ_DISABLED;
554 if (desc->chip->shutdown)
555 desc->chip->shutdown(irq);
557 desc->chip->disable(irq);
559 spin_unlock_irqrestore(&desc->lock, flags);
560 unregister_handler_proc(irq, action);
562 /* Make sure it's not being used on another CPU */
563 synchronize_irq(irq);
564 #ifdef CONFIG_DEBUG_SHIRQ
566 * It's a shared IRQ -- the driver ought to be
567 * prepared for it to happen even now it's
568 * being freed, so let's make sure.... We do
569 * this after actually deregistering it, to
570 * make sure that a 'real' IRQ doesn't run in
571 * parallel with our fake
573 if (action->flags & IRQF_SHARED) {
574 local_irq_save(flags);
575 action->handler(irq, dev_id);
576 local_irq_restore(flags);
582 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
583 #ifdef CONFIG_DEBUG_SHIRQ
586 spin_unlock_irqrestore(&desc->lock, flags);
590 EXPORT_SYMBOL(free_irq);
593 * request_irq - allocate an interrupt line
594 * @irq: Interrupt line to allocate
595 * @handler: Function to be called when the IRQ occurs
596 * @irqflags: Interrupt type flags
597 * @devname: An ascii name for the claiming device
598 * @dev_id: A cookie passed back to the handler function
600 * This call allocates interrupt resources and enables the
601 * interrupt line and IRQ handling. From the point this
602 * call is made your handler function may be invoked. Since
603 * your handler function must clear any interrupt the board
604 * raises, you must take care both to initialise your hardware
605 * and to set up the interrupt handler in the right order.
607 * Dev_id must be globally unique. Normally the address of the
608 * device data structure is used as the cookie. Since the handler
609 * receives this value it makes sense to use it.
611 * If your interrupt is shared you must pass a non NULL dev_id
612 * as this is required when freeing the interrupt.
616 * IRQF_SHARED Interrupt is shared
617 * IRQF_DISABLED Disable local interrupts while processing
618 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
619 * IRQF_TRIGGER_* Specify active edge(s) or level
622 int request_irq(unsigned int irq, irq_handler_t handler,
623 unsigned long irqflags, const char *devname, void *dev_id)
625 struct irqaction *action;
627 struct irq_desc *desc;
629 #ifdef CONFIG_LOCKDEP
631 * Lockdep wants atomic interrupt handlers:
633 irqflags |= IRQF_DISABLED;
636 * Sanity-check: shared interrupts must pass in a real dev-ID,
637 * otherwise we'll have trouble later trying to figure out
638 * which interrupt is which (messes up the interrupt freeing
641 if ((irqflags & IRQF_SHARED) && !dev_id)
644 desc = irq_to_desc(irq);
648 if (desc->status & IRQ_NOREQUEST)
653 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
657 action->handler = handler;
658 action->flags = irqflags;
659 cpus_clear(action->mask);
660 action->name = devname;
662 action->dev_id = dev_id;
664 retval = setup_irq(irq, action);
668 #ifdef CONFIG_DEBUG_SHIRQ
669 if (irqflags & IRQF_SHARED) {
671 * It's a shared IRQ -- the driver ought to be prepared for it
672 * to happen immediately, so let's make sure....
673 * We disable the irq to make sure that a 'real' IRQ doesn't
674 * run in parallel with our fake.
679 local_irq_save(flags);
681 handler(irq, dev_id);
683 local_irq_restore(flags);
689 EXPORT_SYMBOL(request_irq);