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
);
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 desc
->affinity
= cpumask
;
95 desc
->chip
->set_affinity(irq
, cpumask
);
97 desc
->status
|= IRQ_MOVE_PENDING
;
98 desc
->pending_mask
= cpumask
;
101 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
)
117 if (!irq_can_set_affinity(irq
))
120 cpus_and(mask
, cpu_online_map
, irq_default_affinity
);
123 * Preserve an userspace affinity setup, but make sure that
124 * one of the targets is online.
126 if (desc
->status
& IRQ_AFFINITY_SET
) {
127 if (cpus_intersects(desc
->affinity
, cpu_online_map
))
128 mask
= desc
->affinity
;
130 desc
->status
&= ~IRQ_AFFINITY_SET
;
133 desc
->affinity
= mask
;
134 desc
->chip
->set_affinity(irq
, mask
);
139 static inline int do_irq_select_affinity(unsigned int irq
, struct irq_desc
*d
)
141 return irq_select_affinity(irq
);
146 * Called when affinity is set via /proc/irq
148 int irq_select_affinity_usr(unsigned int irq
)
150 struct irq_desc
*desc
= irq_to_desc(irq
);
154 spin_lock_irqsave(&desc
->lock
, flags
);
155 ret
= do_irq_select_affinity(irq
, desc
);
156 spin_unlock_irqrestore(&desc
->lock
, flags
);
162 static inline int do_select_irq_affinity(int irq
, struct irq_desc
*desc
)
169 * disable_irq_nosync - disable an irq without waiting
170 * @irq: Interrupt to disable
172 * Disable the selected interrupt line. Disables and Enables are
174 * Unlike disable_irq(), this function does not ensure existing
175 * instances of the IRQ handler have completed before returning.
177 * This function may be called from IRQ context.
179 void disable_irq_nosync(unsigned int irq
)
181 struct irq_desc
*desc
= irq_to_desc(irq
);
187 spin_lock_irqsave(&desc
->lock
, flags
);
188 if (!desc
->depth
++) {
189 desc
->status
|= IRQ_DISABLED
;
190 desc
->chip
->disable(irq
);
192 spin_unlock_irqrestore(&desc
->lock
, flags
);
194 EXPORT_SYMBOL(disable_irq_nosync
);
197 * disable_irq - disable an irq and wait for completion
198 * @irq: Interrupt to disable
200 * Disable the selected interrupt line. Enables and Disables are
202 * This function waits for any pending IRQ handlers for this interrupt
203 * to complete before returning. If you use this function while
204 * holding a resource the IRQ handler may need you will deadlock.
206 * This function may be called - with care - from IRQ context.
208 void disable_irq(unsigned int irq
)
210 struct irq_desc
*desc
= irq_to_desc(irq
);
215 disable_irq_nosync(irq
);
217 synchronize_irq(irq
);
219 EXPORT_SYMBOL(disable_irq
);
221 static void __enable_irq(struct irq_desc
*desc
, unsigned int irq
)
223 switch (desc
->depth
) {
225 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
228 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
230 /* Prevent probing on this irq: */
231 desc
->status
= status
| IRQ_NOPROBE
;
232 check_irq_resend(desc
, irq
);
241 * enable_irq - enable handling of an irq
242 * @irq: Interrupt to enable
244 * Undoes the effect of one call to disable_irq(). If this
245 * matches the last disable, processing of interrupts on this
246 * IRQ line is re-enabled.
248 * This function may be called from IRQ context.
250 void enable_irq(unsigned int irq
)
252 struct irq_desc
*desc
= irq_to_desc(irq
);
258 spin_lock_irqsave(&desc
->lock
, flags
);
259 __enable_irq(desc
, irq
);
260 spin_unlock_irqrestore(&desc
->lock
, flags
);
262 EXPORT_SYMBOL(enable_irq
);
264 static int set_irq_wake_real(unsigned int irq
, unsigned int on
)
266 struct irq_desc
*desc
= irq_to_desc(irq
);
269 if (desc
->chip
->set_wake
)
270 ret
= desc
->chip
->set_wake(irq
, on
);
276 * set_irq_wake - control irq power management wakeup
277 * @irq: interrupt to control
278 * @on: enable/disable power management wakeup
280 * Enable/disable power management wakeup mode, which is
281 * disabled by default. Enables and disables must match,
282 * just as they match for non-wakeup mode support.
284 * Wakeup mode lets this IRQ wake the system from sleep
285 * states like "suspend to RAM".
287 int set_irq_wake(unsigned int irq
, unsigned int on
)
289 struct irq_desc
*desc
= irq_to_desc(irq
);
293 /* wakeup-capable irqs can be shared between drivers that
294 * don't need to have the same sleep mode behaviors.
296 spin_lock_irqsave(&desc
->lock
, flags
);
298 if (desc
->wake_depth
++ == 0) {
299 ret
= set_irq_wake_real(irq
, on
);
301 desc
->wake_depth
= 0;
303 desc
->status
|= IRQ_WAKEUP
;
306 if (desc
->wake_depth
== 0) {
307 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
308 } else if (--desc
->wake_depth
== 0) {
309 ret
= set_irq_wake_real(irq
, on
);
311 desc
->wake_depth
= 1;
313 desc
->status
&= ~IRQ_WAKEUP
;
317 spin_unlock_irqrestore(&desc
->lock
, flags
);
320 EXPORT_SYMBOL(set_irq_wake
);
323 * Internal function that tells the architecture code whether a
324 * particular irq has been exclusively allocated or is available
327 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
329 struct irq_desc
*desc
= irq_to_desc(irq
);
330 struct irqaction
*action
;
335 if (desc
->status
& IRQ_NOREQUEST
)
338 action
= desc
->action
;
340 if (irqflags
& action
->flags
& IRQF_SHARED
)
346 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
349 * If the architecture still has not overriden
350 * the flow handler then zap the default. This
351 * should catch incorrect flow-type setting.
353 if (desc
->handle_irq
== &handle_bad_irq
)
354 desc
->handle_irq
= NULL
;
357 int __irq_set_trigger(struct irq_desc
*desc
, unsigned int irq
,
361 struct irq_chip
*chip
= desc
->chip
;
363 if (!chip
|| !chip
->set_type
) {
365 * IRQF_TRIGGER_* but the PIC does not support multiple
368 pr_warning("No set_type function for IRQ %d (%s)\n", irq
,
369 chip
? (chip
->name
? : "unknown") : "unknown");
373 ret
= chip
->set_type(irq
, flags
& IRQF_TRIGGER_MASK
);
376 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
377 (int)(flags
& IRQF_TRIGGER_MASK
),
378 irq
, chip
->set_type
);
380 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
381 desc
->status
&= ~IRQ_TYPE_SENSE_MASK
;
382 desc
->status
|= flags
& IRQ_TYPE_SENSE_MASK
;
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
, new->flags
);
465 spin_unlock_irqrestore(&desc
->lock
, flags
);
469 compat_irq_chip_set_default_handler(desc
);
470 #if defined(CONFIG_IRQ_PER_CPU)
471 if (new->flags
& IRQF_PERCPU
)
472 desc
->status
|= IRQ_PER_CPU
;
475 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
476 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
478 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
480 desc
->status
&= ~IRQ_DISABLED
;
481 desc
->chip
->startup(irq
);
483 /* Undo nested disables: */
486 /* Set default affinity mask once everything is setup */
487 do_irq_select_affinity(irq
, desc
);
489 } else if ((new->flags
& IRQF_TRIGGER_MASK
)
490 && (new->flags
& IRQF_TRIGGER_MASK
)
491 != (desc
->status
& IRQ_TYPE_SENSE_MASK
)) {
492 /* hope the handler works with the actual trigger mode... */
493 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
494 irq
, (int)(desc
->status
& IRQ_TYPE_SENSE_MASK
),
495 (int)(new->flags
& IRQF_TRIGGER_MASK
));
500 /* Exclude IRQ from balancing */
501 if (new->flags
& IRQF_NOBALANCING
)
502 desc
->status
|= IRQ_NO_BALANCING
;
504 /* Reset broken irq detection when installing new handler */
506 desc
->irqs_unhandled
= 0;
509 * Check whether we disabled the irq via the spurious handler
510 * before. Reenable it and give it another chance.
512 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
513 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
514 __enable_irq(desc
, irq
);
517 spin_unlock_irqrestore(&desc
->lock
, flags
);
520 register_irq_proc(irq
, desc
);
522 register_handler_proc(irq
, new);
527 #ifdef CONFIG_DEBUG_SHIRQ
528 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
529 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
531 printk(KERN_ERR
"current handler: %s\n", old_name
);
535 spin_unlock_irqrestore(&desc
->lock
, flags
);
540 * setup_irq - setup an interrupt
541 * @irq: Interrupt line to setup
542 * @act: irqaction for the interrupt
544 * Used to statically setup interrupts in the early boot process.
546 int setup_irq(unsigned int irq
, struct irqaction
*act
)
548 struct irq_desc
*desc
= irq_to_desc(irq
);
550 return __setup_irq(irq
, desc
, act
);
554 * free_irq - free an interrupt
555 * @irq: Interrupt line to free
556 * @dev_id: Device identity to free
558 * Remove an interrupt handler. The handler is removed and if the
559 * interrupt line is no longer in use by any driver it is disabled.
560 * On a shared IRQ the caller must ensure the interrupt is disabled
561 * on the card it drives before calling this function. The function
562 * does not return until any executing interrupts for this IRQ
565 * This function must not be called from interrupt context.
567 void free_irq(unsigned int irq
, void *dev_id
)
569 struct irq_desc
*desc
= irq_to_desc(irq
);
570 struct irqaction
**p
;
573 WARN_ON(in_interrupt());
578 spin_lock_irqsave(&desc
->lock
, flags
);
581 struct irqaction
*action
= *p
;
584 struct irqaction
**pp
= p
;
587 if (action
->dev_id
!= dev_id
)
590 /* Found it - now remove it from the list of entries */
593 /* Currently used only by UML, might disappear one day.*/
594 #ifdef CONFIG_IRQ_RELEASE_METHOD
595 if (desc
->chip
->release
)
596 desc
->chip
->release(irq
, dev_id
);
600 desc
->status
|= IRQ_DISABLED
;
601 if (desc
->chip
->shutdown
)
602 desc
->chip
->shutdown(irq
);
604 desc
->chip
->disable(irq
);
606 spin_unlock_irqrestore(&desc
->lock
, flags
);
607 unregister_handler_proc(irq
, action
);
609 /* Make sure it's not being used on another CPU */
610 synchronize_irq(irq
);
611 #ifdef CONFIG_DEBUG_SHIRQ
613 * It's a shared IRQ -- the driver ought to be
614 * prepared for it to happen even now it's
615 * being freed, so let's make sure.... We do
616 * this after actually deregistering it, to
617 * make sure that a 'real' IRQ doesn't run in
618 * parallel with our fake
620 if (action
->flags
& IRQF_SHARED
) {
621 local_irq_save(flags
);
622 action
->handler(irq
, dev_id
);
623 local_irq_restore(flags
);
629 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
630 #ifdef CONFIG_DEBUG_SHIRQ
633 spin_unlock_irqrestore(&desc
->lock
, flags
);
637 EXPORT_SYMBOL(free_irq
);
640 * request_irq - allocate an interrupt line
641 * @irq: Interrupt line to allocate
642 * @handler: Function to be called when the IRQ occurs
643 * @irqflags: Interrupt type flags
644 * @devname: An ascii name for the claiming device
645 * @dev_id: A cookie passed back to the handler function
647 * This call allocates interrupt resources and enables the
648 * interrupt line and IRQ handling. From the point this
649 * call is made your handler function may be invoked. Since
650 * your handler function must clear any interrupt the board
651 * raises, you must take care both to initialise your hardware
652 * and to set up the interrupt handler in the right order.
654 * Dev_id must be globally unique. Normally the address of the
655 * device data structure is used as the cookie. Since the handler
656 * receives this value it makes sense to use it.
658 * If your interrupt is shared you must pass a non NULL dev_id
659 * as this is required when freeing the interrupt.
663 * IRQF_SHARED Interrupt is shared
664 * IRQF_DISABLED Disable local interrupts while processing
665 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
666 * IRQF_TRIGGER_* Specify active edge(s) or level
669 int request_irq(unsigned int irq
, irq_handler_t handler
,
670 unsigned long irqflags
, const char *devname
, void *dev_id
)
672 struct irqaction
*action
;
673 struct irq_desc
*desc
;
676 #ifdef CONFIG_LOCKDEP
678 * Lockdep wants atomic interrupt handlers:
680 irqflags
|= IRQF_DISABLED
;
683 * Sanity-check: shared interrupts must pass in a real dev-ID,
684 * otherwise we'll have trouble later trying to figure out
685 * which interrupt is which (messes up the interrupt freeing
688 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
691 desc
= irq_to_desc(irq
);
695 if (desc
->status
& IRQ_NOREQUEST
)
700 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
704 action
->handler
= handler
;
705 action
->flags
= irqflags
;
706 cpus_clear(action
->mask
);
707 action
->name
= devname
;
709 action
->dev_id
= dev_id
;
711 retval
= __setup_irq(irq
, desc
, action
);
715 #ifdef CONFIG_DEBUG_SHIRQ
716 if (irqflags
& IRQF_SHARED
) {
718 * It's a shared IRQ -- the driver ought to be prepared for it
719 * to happen immediately, so let's make sure....
720 * We disable the irq to make sure that a 'real' IRQ doesn't
721 * run in parallel with our fake.
726 local_irq_save(flags
);
728 handler(irq
, dev_id
);
730 local_irq_restore(flags
);
736 EXPORT_SYMBOL(request_irq
);