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_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_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_desc
+ irq
;
86 if (!desc
->chip
->set_affinity
)
89 set_balance_irq_affinity(irq
, cpumask
);
91 #ifdef CONFIG_GENERIC_PENDING_IRQ
92 set_pending_irq(irq
, cpumask
);
94 desc
->affinity
= cpumask
;
95 desc
->chip
->set_affinity(irq
, cpumask
);
100 #ifndef CONFIG_AUTO_IRQ_AFFINITY
102 * Generic version of the affinity autoselector.
104 int irq_select_affinity(unsigned int irq
)
108 if (!irq_can_set_affinity(irq
))
111 cpus_and(mask
, cpu_online_map
, irq_default_affinity
);
113 irq_desc
[irq
].affinity
= mask
;
114 irq_desc
[irq
].chip
->set_affinity(irq
, mask
);
116 set_balance_irq_affinity(irq
, mask
);
124 * disable_irq_nosync - disable an irq without waiting
125 * @irq: Interrupt to disable
127 * Disable the selected interrupt line. Disables and Enables are
129 * Unlike disable_irq(), this function does not ensure existing
130 * instances of the IRQ handler have completed before returning.
132 * This function may be called from IRQ context.
134 void disable_irq_nosync(unsigned int irq
)
136 struct irq_desc
*desc
= irq_desc
+ irq
;
142 spin_lock_irqsave(&desc
->lock
, flags
);
143 if (!desc
->depth
++) {
144 desc
->status
|= IRQ_DISABLED
;
145 desc
->chip
->disable(irq
);
147 spin_unlock_irqrestore(&desc
->lock
, flags
);
149 EXPORT_SYMBOL(disable_irq_nosync
);
152 * disable_irq - disable an irq and wait for completion
153 * @irq: Interrupt to disable
155 * Disable the selected interrupt line. Enables and Disables are
157 * This function waits for any pending IRQ handlers for this interrupt
158 * to complete before returning. If you use this function while
159 * holding a resource the IRQ handler may need you will deadlock.
161 * This function may be called - with care - from IRQ context.
163 void disable_irq(unsigned int irq
)
165 struct irq_desc
*desc
= irq_desc
+ irq
;
170 disable_irq_nosync(irq
);
172 synchronize_irq(irq
);
174 EXPORT_SYMBOL(disable_irq
);
176 static void __enable_irq(struct irq_desc
*desc
, unsigned int irq
)
178 switch (desc
->depth
) {
180 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
183 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
185 /* Prevent probing on this irq: */
186 desc
->status
= status
| IRQ_NOPROBE
;
187 check_irq_resend(desc
, irq
);
196 * enable_irq - enable handling of an irq
197 * @irq: Interrupt to enable
199 * Undoes the effect of one call to disable_irq(). If this
200 * matches the last disable, processing of interrupts on this
201 * IRQ line is re-enabled.
203 * This function may be called from IRQ context.
205 void enable_irq(unsigned int irq
)
207 struct irq_desc
*desc
= irq_desc
+ irq
;
213 spin_lock_irqsave(&desc
->lock
, flags
);
214 __enable_irq(desc
, irq
);
215 spin_unlock_irqrestore(&desc
->lock
, flags
);
217 EXPORT_SYMBOL(enable_irq
);
219 int set_irq_wake_real(unsigned int irq
, unsigned int on
)
221 struct irq_desc
*desc
= irq_desc
+ irq
;
224 if (desc
->chip
->set_wake
)
225 ret
= desc
->chip
->set_wake(irq
, on
);
231 * set_irq_wake - control irq power management wakeup
232 * @irq: interrupt to control
233 * @on: enable/disable power management wakeup
235 * Enable/disable power management wakeup mode, which is
236 * disabled by default. Enables and disables must match,
237 * just as they match for non-wakeup mode support.
239 * Wakeup mode lets this IRQ wake the system from sleep
240 * states like "suspend to RAM".
242 int set_irq_wake(unsigned int irq
, unsigned int on
)
244 struct irq_desc
*desc
= irq_desc
+ irq
;
248 /* wakeup-capable irqs can be shared between drivers that
249 * don't need to have the same sleep mode behaviors.
251 spin_lock_irqsave(&desc
->lock
, flags
);
253 if (desc
->wake_depth
++ == 0) {
254 ret
= set_irq_wake_real(irq
, on
);
256 desc
->wake_depth
= 0;
258 desc
->status
|= IRQ_WAKEUP
;
261 if (desc
->wake_depth
== 0) {
262 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
263 } else if (--desc
->wake_depth
== 0) {
264 ret
= set_irq_wake_real(irq
, on
);
266 desc
->wake_depth
= 1;
268 desc
->status
&= ~IRQ_WAKEUP
;
272 spin_unlock_irqrestore(&desc
->lock
, flags
);
275 EXPORT_SYMBOL(set_irq_wake
);
278 * Internal function that tells the architecture code whether a
279 * particular irq has been exclusively allocated or is available
282 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
284 struct irqaction
*action
;
286 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
289 action
= irq_desc
[irq
].action
;
291 if (irqflags
& action
->flags
& IRQF_SHARED
)
297 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
300 * If the architecture still has not overriden
301 * the flow handler then zap the default. This
302 * should catch incorrect flow-type setting.
304 if (desc
->handle_irq
== &handle_bad_irq
)
305 desc
->handle_irq
= NULL
;
308 static int __irq_set_trigger(struct irq_chip
*chip
, unsigned int irq
,
313 if (!chip
|| !chip
->set_type
) {
315 * IRQF_TRIGGER_* but the PIC does not support multiple
318 pr_warning("No set_type function for IRQ %d (%s)\n", irq
,
319 chip
? (chip
->name
? : "unknown") : "unknown");
323 ret
= chip
->set_type(irq
, flags
& IRQF_TRIGGER_MASK
);
326 pr_err("setting flow type for irq %u failed (%pF)\n",
327 irq
, chip
->set_type
);
333 * Internal function to register an irqaction - typically used to
334 * allocate special interrupts that are part of the architecture.
336 int setup_irq(unsigned int irq
, struct irqaction
*new)
338 struct irq_desc
*desc
= irq_desc
+ irq
;
339 struct irqaction
*old
, **p
;
340 const char *old_name
= NULL
;
348 if (desc
->chip
== &no_irq_chip
)
351 * Some drivers like serial.c use request_irq() heavily,
352 * so we have to be careful not to interfere with a
355 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
357 * This function might sleep, we want to call it first,
358 * outside of the atomic block.
359 * Yes, this might clear the entropy pool if the wrong
360 * driver is attempted to be loaded, without actually
361 * installing a new handler, but is this really a problem,
362 * only the sysadmin is able to do this.
364 rand_initialize_irq(irq
);
368 * The following block of code has to be executed atomically
370 spin_lock_irqsave(&desc
->lock
, flags
);
375 * Can't share interrupts unless both agree to and are
376 * the same type (level, edge, polarity). So both flag
377 * fields must have IRQF_SHARED set and the bits which
378 * set the trigger type must match.
380 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
381 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
382 old_name
= old
->name
;
386 #if defined(CONFIG_IRQ_PER_CPU)
387 /* All handlers must agree on per-cpuness */
388 if ((old
->flags
& IRQF_PERCPU
) !=
389 (new->flags
& IRQF_PERCPU
))
393 /* add new interrupt at end of irq queue */
402 irq_chip_set_defaults(desc
->chip
);
404 /* Setup the type (level, edge polarity) if configured: */
405 if (new->flags
& IRQF_TRIGGER_MASK
) {
406 ret
= __irq_set_trigger(desc
->chip
, irq
, new->flags
);
409 spin_unlock_irqrestore(&desc
->lock
, flags
);
413 compat_irq_chip_set_default_handler(desc
);
414 #if defined(CONFIG_IRQ_PER_CPU)
415 if (new->flags
& IRQF_PERCPU
)
416 desc
->status
|= IRQ_PER_CPU
;
419 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
420 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
422 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
424 desc
->status
&= ~IRQ_DISABLED
;
425 if (desc
->chip
->startup
)
426 desc
->chip
->startup(irq
);
428 desc
->chip
->enable(irq
);
430 /* Undo nested disables: */
433 /* Set default affinity mask once everything is setup */
434 irq_select_affinity(irq
);
439 /* Exclude IRQ from balancing */
440 if (new->flags
& IRQF_NOBALANCING
)
441 desc
->status
|= IRQ_NO_BALANCING
;
443 /* Reset broken irq detection when installing new handler */
445 desc
->irqs_unhandled
= 0;
448 * Check whether we disabled the irq via the spurious handler
449 * before. Reenable it and give it another chance.
451 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
452 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
453 __enable_irq(desc
, irq
);
456 spin_unlock_irqrestore(&desc
->lock
, flags
);
459 register_irq_proc(irq
);
461 register_handler_proc(irq
, new);
466 #ifdef CONFIG_DEBUG_SHIRQ
467 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
468 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
470 printk(KERN_ERR
"current handler: %s\n", old_name
);
474 spin_unlock_irqrestore(&desc
->lock
, flags
);
479 * free_irq - free an interrupt
480 * @irq: Interrupt line to free
481 * @dev_id: Device identity to free
483 * Remove an interrupt handler. The handler is removed and if the
484 * interrupt line is no longer in use by any driver it is disabled.
485 * On a shared IRQ the caller must ensure the interrupt is disabled
486 * on the card it drives before calling this function. The function
487 * does not return until any executing interrupts for this IRQ
490 * This function must not be called from interrupt context.
492 void free_irq(unsigned int irq
, void *dev_id
)
494 struct irq_desc
*desc
;
495 struct irqaction
**p
;
498 WARN_ON(in_interrupt());
502 desc
= irq_desc
+ irq
;
503 spin_lock_irqsave(&desc
->lock
, flags
);
506 struct irqaction
*action
= *p
;
509 struct irqaction
**pp
= p
;
512 if (action
->dev_id
!= dev_id
)
515 /* Found it - now remove it from the list of entries */
518 /* Currently used only by UML, might disappear one day.*/
519 #ifdef CONFIG_IRQ_RELEASE_METHOD
520 if (desc
->chip
->release
)
521 desc
->chip
->release(irq
, dev_id
);
525 desc
->status
|= IRQ_DISABLED
;
526 if (desc
->chip
->shutdown
)
527 desc
->chip
->shutdown(irq
);
529 desc
->chip
->disable(irq
);
531 spin_unlock_irqrestore(&desc
->lock
, flags
);
532 unregister_handler_proc(irq
, action
);
534 /* Make sure it's not being used on another CPU */
535 synchronize_irq(irq
);
536 #ifdef CONFIG_DEBUG_SHIRQ
538 * It's a shared IRQ -- the driver ought to be
539 * prepared for it to happen even now it's
540 * being freed, so let's make sure.... We do
541 * this after actually deregistering it, to
542 * make sure that a 'real' IRQ doesn't run in
543 * parallel with our fake
545 if (action
->flags
& IRQF_SHARED
) {
546 local_irq_save(flags
);
547 action
->handler(irq
, dev_id
);
548 local_irq_restore(flags
);
554 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
555 #ifdef CONFIG_DEBUG_SHIRQ
558 spin_unlock_irqrestore(&desc
->lock
, flags
);
562 EXPORT_SYMBOL(free_irq
);
565 * request_irq - allocate an interrupt line
566 * @irq: Interrupt line to allocate
567 * @handler: Function to be called when the IRQ occurs
568 * @irqflags: Interrupt type flags
569 * @devname: An ascii name for the claiming device
570 * @dev_id: A cookie passed back to the handler function
572 * This call allocates interrupt resources and enables the
573 * interrupt line and IRQ handling. From the point this
574 * call is made your handler function may be invoked. Since
575 * your handler function must clear any interrupt the board
576 * raises, you must take care both to initialise your hardware
577 * and to set up the interrupt handler in the right order.
579 * Dev_id must be globally unique. Normally the address of the
580 * device data structure is used as the cookie. Since the handler
581 * receives this value it makes sense to use it.
583 * If your interrupt is shared you must pass a non NULL dev_id
584 * as this is required when freeing the interrupt.
588 * IRQF_SHARED Interrupt is shared
589 * IRQF_DISABLED Disable local interrupts while processing
590 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
593 int request_irq(unsigned int irq
, irq_handler_t handler
,
594 unsigned long irqflags
, const char *devname
, void *dev_id
)
596 struct irqaction
*action
;
599 #ifdef CONFIG_LOCKDEP
601 * Lockdep wants atomic interrupt handlers:
603 irqflags
|= IRQF_DISABLED
;
606 * Sanity-check: shared interrupts must pass in a real dev-ID,
607 * otherwise we'll have trouble later trying to figure out
608 * which interrupt is which (messes up the interrupt freeing
611 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
615 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
620 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
624 action
->handler
= handler
;
625 action
->flags
= irqflags
;
626 cpus_clear(action
->mask
);
627 action
->name
= devname
;
629 action
->dev_id
= dev_id
;
631 #ifdef CONFIG_DEBUG_SHIRQ
632 if (irqflags
& IRQF_SHARED
) {
634 * It's a shared IRQ -- the driver ought to be prepared for it
635 * to happen immediately, so let's make sure....
636 * We do this before actually registering it, to make sure that
637 * a 'real' IRQ doesn't run in parallel with our fake
641 local_irq_save(flags
);
642 handler(irq
, dev_id
);
643 local_irq_restore(flags
);
647 retval
= setup_irq(irq
, action
);
653 EXPORT_SYMBOL(request_irq
);