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
;
148 desc
= irq_to_desc(irq
);
152 spin_lock_irqsave(&desc
->lock
, flags
);
153 if (!desc
->depth
++) {
154 desc
->status
|= IRQ_DISABLED
;
155 desc
->chip
->disable(irq
);
157 spin_unlock_irqrestore(&desc
->lock
, flags
);
159 EXPORT_SYMBOL(disable_irq_nosync
);
162 * disable_irq - disable an irq and wait for completion
163 * @irq: Interrupt to disable
165 * Disable the selected interrupt line. Enables and Disables are
167 * This function waits for any pending IRQ handlers for this interrupt
168 * to complete before returning. If you use this function while
169 * holding a resource the IRQ handler may need you will deadlock.
171 * This function may be called - with care - from IRQ context.
173 void disable_irq(unsigned int irq
)
175 struct irq_desc
*desc
;
177 desc
= irq_to_desc(irq
);
181 disable_irq_nosync(irq
);
183 synchronize_irq(irq
);
185 EXPORT_SYMBOL(disable_irq
);
187 static void __enable_irq(struct irq_desc
*desc
, unsigned int irq
)
189 switch (desc
->depth
) {
191 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
194 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
196 /* Prevent probing on this irq: */
197 desc
->status
= status
| IRQ_NOPROBE
;
198 check_irq_resend(desc
, irq
);
207 * enable_irq - enable handling of an irq
208 * @irq: Interrupt to enable
210 * Undoes the effect of one call to disable_irq(). If this
211 * matches the last disable, processing of interrupts on this
212 * IRQ line is re-enabled.
214 * This function may be called from IRQ context.
216 void enable_irq(unsigned int irq
)
218 struct irq_desc
*desc
;
221 desc
= irq_to_desc(irq
);
225 spin_lock_irqsave(&desc
->lock
, flags
);
226 __enable_irq(desc
, irq
);
227 spin_unlock_irqrestore(&desc
->lock
, flags
);
229 EXPORT_SYMBOL(enable_irq
);
231 static int set_irq_wake_real(unsigned int irq
, unsigned int on
)
233 struct irq_desc
*desc
= irq_to_desc(irq
);
236 if (desc
->chip
->set_wake
)
237 ret
= desc
->chip
->set_wake(irq
, on
);
243 * set_irq_wake - control irq power management wakeup
244 * @irq: interrupt to control
245 * @on: enable/disable power management wakeup
247 * Enable/disable power management wakeup mode, which is
248 * disabled by default. Enables and disables must match,
249 * just as they match for non-wakeup mode support.
251 * Wakeup mode lets this IRQ wake the system from sleep
252 * states like "suspend to RAM".
254 int set_irq_wake(unsigned int irq
, unsigned int on
)
256 struct irq_desc
*desc
= irq_to_desc(irq
);
260 /* wakeup-capable irqs can be shared between drivers that
261 * don't need to have the same sleep mode behaviors.
263 spin_lock_irqsave(&desc
->lock
, flags
);
265 if (desc
->wake_depth
++ == 0) {
266 ret
= set_irq_wake_real(irq
, on
);
268 desc
->wake_depth
= 0;
270 desc
->status
|= IRQ_WAKEUP
;
273 if (desc
->wake_depth
== 0) {
274 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
275 } else if (--desc
->wake_depth
== 0) {
276 ret
= set_irq_wake_real(irq
, on
);
278 desc
->wake_depth
= 1;
280 desc
->status
&= ~IRQ_WAKEUP
;
284 spin_unlock_irqrestore(&desc
->lock
, flags
);
287 EXPORT_SYMBOL(set_irq_wake
);
290 * Internal function that tells the architecture code whether a
291 * particular irq has been exclusively allocated or is available
294 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
296 struct irq_desc
*desc
;
297 struct irqaction
*action
;
299 desc
= irq_to_desc(irq
);
303 if (desc
->status
& IRQ_NOREQUEST
)
306 action
= desc
->action
;
308 if (irqflags
& action
->flags
& IRQF_SHARED
)
314 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
317 * If the architecture still has not overriden
318 * the flow handler then zap the default. This
319 * should catch incorrect flow-type setting.
321 if (desc
->handle_irq
== &handle_bad_irq
)
322 desc
->handle_irq
= NULL
;
325 int __irq_set_trigger(struct irq_desc
*desc
, unsigned int irq
,
329 struct irq_chip
*chip
= desc
->chip
;
331 if (!chip
|| !chip
->set_type
) {
333 * IRQF_TRIGGER_* but the PIC does not support multiple
336 pr_warning("No set_type function for IRQ %d (%s)\n", irq
,
337 chip
? (chip
->name
? : "unknown") : "unknown");
341 ret
= chip
->set_type(irq
, flags
& IRQF_TRIGGER_MASK
);
344 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
345 (int)(flags
& IRQF_TRIGGER_MASK
),
346 irq
, chip
->set_type
);
348 /* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
349 desc
->status
&= ~IRQ_TYPE_SENSE_MASK
;
350 desc
->status
|= flags
& IRQ_TYPE_SENSE_MASK
;
357 * Internal function to register an irqaction - typically used to
358 * allocate special interrupts that are part of the architecture.
360 int setup_irq(unsigned int irq
, struct irqaction
*new)
362 struct irq_desc
*desc
;
363 struct irqaction
*old
, **p
;
364 const char *old_name
= NULL
;
369 desc
= irq_to_desc(irq
);
373 if (desc
->chip
== &no_irq_chip
)
376 * Some drivers like serial.c use request_irq() heavily,
377 * so we have to be careful not to interfere with a
380 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
382 * This function might sleep, we want to call it first,
383 * outside of the atomic block.
384 * Yes, this might clear the entropy pool if the wrong
385 * driver is attempted to be loaded, without actually
386 * installing a new handler, but is this really a problem,
387 * only the sysadmin is able to do this.
389 rand_initialize_irq(irq
);
393 * The following block of code has to be executed atomically
395 spin_lock_irqsave(&desc
->lock
, flags
);
400 * Can't share interrupts unless both agree to and are
401 * the same type (level, edge, polarity). So both flag
402 * fields must have IRQF_SHARED set and the bits which
403 * set the trigger type must match.
405 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
406 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
407 old_name
= old
->name
;
411 #if defined(CONFIG_IRQ_PER_CPU)
412 /* All handlers must agree on per-cpuness */
413 if ((old
->flags
& IRQF_PERCPU
) !=
414 (new->flags
& IRQF_PERCPU
))
418 /* add new interrupt at end of irq queue */
427 irq_chip_set_defaults(desc
->chip
);
429 /* Setup the type (level, edge polarity) if configured: */
430 if (new->flags
& IRQF_TRIGGER_MASK
) {
431 ret
= __irq_set_trigger(desc
, irq
, new->flags
);
434 spin_unlock_irqrestore(&desc
->lock
, flags
);
438 compat_irq_chip_set_default_handler(desc
);
439 #if defined(CONFIG_IRQ_PER_CPU)
440 if (new->flags
& IRQF_PERCPU
)
441 desc
->status
|= IRQ_PER_CPU
;
444 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
445 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
447 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
449 desc
->status
&= ~IRQ_DISABLED
;
450 desc
->chip
->startup(irq
);
452 /* Undo nested disables: */
455 /* Set default affinity mask once everything is setup */
456 irq_select_affinity(irq
);
458 } else if ((new->flags
& IRQF_TRIGGER_MASK
)
459 && (new->flags
& IRQF_TRIGGER_MASK
)
460 != (desc
->status
& IRQ_TYPE_SENSE_MASK
)) {
461 /* hope the handler works with the actual trigger mode... */
462 pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
463 irq
, (int)(desc
->status
& IRQ_TYPE_SENSE_MASK
),
464 (int)(new->flags
& IRQF_TRIGGER_MASK
));
469 /* Exclude IRQ from balancing */
470 if (new->flags
& IRQF_NOBALANCING
)
471 desc
->status
|= IRQ_NO_BALANCING
;
473 /* Reset broken irq detection when installing new handler */
475 desc
->irqs_unhandled
= 0;
478 * Check whether we disabled the irq via the spurious handler
479 * before. Reenable it and give it another chance.
481 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
482 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
483 __enable_irq(desc
, irq
);
486 spin_unlock_irqrestore(&desc
->lock
, flags
);
489 register_irq_proc(irq
, desc
);
491 register_handler_proc(irq
, new);
496 #ifdef CONFIG_DEBUG_SHIRQ
497 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
498 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
500 printk(KERN_ERR
"current handler: %s\n", old_name
);
504 spin_unlock_irqrestore(&desc
->lock
, flags
);
509 * free_irq - free an interrupt
510 * @irq: Interrupt line to free
511 * @dev_id: Device identity to free
513 * Remove an interrupt handler. The handler is removed and if the
514 * interrupt line is no longer in use by any driver it is disabled.
515 * On a shared IRQ the caller must ensure the interrupt is disabled
516 * on the card it drives before calling this function. The function
517 * does not return until any executing interrupts for this IRQ
520 * This function must not be called from interrupt context.
522 void free_irq(unsigned int irq
, void *dev_id
)
524 struct irq_desc
*desc
;
525 struct irqaction
**p
;
528 WARN_ON(in_interrupt());
530 desc
= irq_to_desc(irq
);
534 spin_lock_irqsave(&desc
->lock
, flags
);
537 struct irqaction
*action
= *p
;
540 struct irqaction
**pp
= p
;
543 if (action
->dev_id
!= dev_id
)
546 /* Found it - now remove it from the list of entries */
549 /* Currently used only by UML, might disappear one day.*/
550 #ifdef CONFIG_IRQ_RELEASE_METHOD
551 if (desc
->chip
->release
)
552 desc
->chip
->release(irq
, dev_id
);
556 desc
->status
|= IRQ_DISABLED
;
557 if (desc
->chip
->shutdown
)
558 desc
->chip
->shutdown(irq
);
560 desc
->chip
->disable(irq
);
562 spin_unlock_irqrestore(&desc
->lock
, flags
);
563 unregister_handler_proc(irq
, action
);
565 /* Make sure it's not being used on another CPU */
566 synchronize_irq(irq
);
567 #ifdef CONFIG_DEBUG_SHIRQ
569 * It's a shared IRQ -- the driver ought to be
570 * prepared for it to happen even now it's
571 * being freed, so let's make sure.... We do
572 * this after actually deregistering it, to
573 * make sure that a 'real' IRQ doesn't run in
574 * parallel with our fake
576 if (action
->flags
& IRQF_SHARED
) {
577 local_irq_save(flags
);
578 action
->handler(irq
, dev_id
);
579 local_irq_restore(flags
);
585 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
586 #ifdef CONFIG_DEBUG_SHIRQ
589 spin_unlock_irqrestore(&desc
->lock
, flags
);
593 EXPORT_SYMBOL(free_irq
);
596 * request_irq - allocate an interrupt line
597 * @irq: Interrupt line to allocate
598 * @handler: Function to be called when the IRQ occurs
599 * @irqflags: Interrupt type flags
600 * @devname: An ascii name for the claiming device
601 * @dev_id: A cookie passed back to the handler function
603 * This call allocates interrupt resources and enables the
604 * interrupt line and IRQ handling. From the point this
605 * call is made your handler function may be invoked. Since
606 * your handler function must clear any interrupt the board
607 * raises, you must take care both to initialise your hardware
608 * and to set up the interrupt handler in the right order.
610 * Dev_id must be globally unique. Normally the address of the
611 * device data structure is used as the cookie. Since the handler
612 * receives this value it makes sense to use it.
614 * If your interrupt is shared you must pass a non NULL dev_id
615 * as this is required when freeing the interrupt.
619 * IRQF_SHARED Interrupt is shared
620 * IRQF_DISABLED Disable local interrupts while processing
621 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
622 * IRQF_TRIGGER_* Specify active edge(s) or level
625 int request_irq(unsigned int irq
, irq_handler_t handler
,
626 unsigned long irqflags
, const char *devname
, void *dev_id
)
628 struct irqaction
*action
;
630 struct irq_desc
*desc
;
632 #ifdef CONFIG_LOCKDEP
634 * Lockdep wants atomic interrupt handlers:
636 irqflags
|= IRQF_DISABLED
;
639 * Sanity-check: shared interrupts must pass in a real dev-ID,
640 * otherwise we'll have trouble later trying to figure out
641 * which interrupt is which (messes up the interrupt freeing
644 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
647 desc
= irq_to_desc(irq
);
651 if (desc
->status
& IRQ_NOREQUEST
)
656 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
660 action
->handler
= handler
;
661 action
->flags
= irqflags
;
662 cpus_clear(action
->mask
);
663 action
->name
= devname
;
665 action
->dev_id
= dev_id
;
667 retval
= setup_irq(irq
, action
);
671 #ifdef CONFIG_DEBUG_SHIRQ
672 if (irqflags
& IRQF_SHARED
) {
674 * It's a shared IRQ -- the driver ought to be prepared for it
675 * to happen immediately, so let's make sure....
676 * We disable the irq to make sure that a 'real' IRQ doesn't
677 * run in parallel with our fake.
682 local_irq_save(flags
);
684 handler(irq
, dev_id
);
686 local_irq_restore(flags
);
692 EXPORT_SYMBOL(request_irq
);