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"
21 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22 * @irq: interrupt number to wait for
24 * This function waits for any pending IRQ handlers for this interrupt
25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
28 * This function may be called - with care - from IRQ context.
30 void synchronize_irq(unsigned int irq
)
32 struct irq_desc
*desc
= irq_desc
+ irq
;
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
45 while (desc
->status
& IRQ_INPROGRESS
)
48 /* Ok, that indicated we're done: double-check carefully. */
49 spin_lock_irqsave(&desc
->lock
, flags
);
50 status
= desc
->status
;
51 spin_unlock_irqrestore(&desc
->lock
, flags
);
53 /* Oops, that failed? */
54 } while (status
& IRQ_INPROGRESS
);
56 EXPORT_SYMBOL(synchronize_irq
);
59 * irq_can_set_affinity - Check if the affinity of a given irq can be set
60 * @irq: Interrupt to check
63 int irq_can_set_affinity(unsigned int irq
)
65 struct irq_desc
*desc
= irq_desc
+ irq
;
67 if (CHECK_IRQ_PER_CPU(desc
->status
) || !desc
->chip
||
68 !desc
->chip
->set_affinity
)
75 * irq_set_affinity - Set the irq affinity of a given irq
76 * @irq: Interrupt to set affinity
80 int irq_set_affinity(unsigned int irq
, cpumask_t cpumask
)
82 struct irq_desc
*desc
= irq_desc
+ irq
;
84 if (!desc
->chip
->set_affinity
)
87 set_balance_irq_affinity(irq
, cpumask
);
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
);
108 * disable_irq_nosync - disable an irq without waiting
109 * @irq: Interrupt to disable
111 * Disable the selected interrupt line. Disables and Enables are
113 * Unlike disable_irq(), this function does not ensure existing
114 * instances of the IRQ handler have completed before returning.
116 * This function may be called from IRQ context.
118 void disable_irq_nosync(unsigned int irq
)
120 struct irq_desc
*desc
= irq_desc
+ irq
;
126 spin_lock_irqsave(&desc
->lock
, flags
);
127 if (!desc
->depth
++) {
128 desc
->status
|= IRQ_DISABLED
;
129 desc
->chip
->disable(irq
);
131 spin_unlock_irqrestore(&desc
->lock
, flags
);
133 EXPORT_SYMBOL(disable_irq_nosync
);
136 * disable_irq - disable an irq and wait for completion
137 * @irq: Interrupt to disable
139 * Disable the selected interrupt line. Enables and Disables are
141 * This function waits for any pending IRQ handlers for this interrupt
142 * to complete before returning. If you use this function while
143 * holding a resource the IRQ handler may need you will deadlock.
145 * This function may be called - with care - from IRQ context.
147 void disable_irq(unsigned int irq
)
149 struct irq_desc
*desc
= irq_desc
+ irq
;
154 disable_irq_nosync(irq
);
156 synchronize_irq(irq
);
158 EXPORT_SYMBOL(disable_irq
);
160 static void __enable_irq(struct irq_desc
*desc
, unsigned int irq
)
162 switch (desc
->depth
) {
164 printk(KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
168 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
170 /* Prevent probing on this irq: */
171 desc
->status
= status
| IRQ_NOPROBE
;
172 check_irq_resend(desc
, irq
);
181 * enable_irq - enable handling of an irq
182 * @irq: Interrupt to enable
184 * Undoes the effect of one call to disable_irq(). If this
185 * matches the last disable, processing of interrupts on this
186 * IRQ line is re-enabled.
188 * This function may be called from IRQ context.
190 void enable_irq(unsigned int irq
)
192 struct irq_desc
*desc
= irq_desc
+ irq
;
198 spin_lock_irqsave(&desc
->lock
, flags
);
199 __enable_irq(desc
, irq
);
200 spin_unlock_irqrestore(&desc
->lock
, flags
);
202 EXPORT_SYMBOL(enable_irq
);
205 * set_irq_wake - control irq power management wakeup
206 * @irq: interrupt to control
207 * @on: enable/disable power management wakeup
209 * Enable/disable power management wakeup mode, which is
210 * disabled by default. Enables and disables must match,
211 * just as they match for non-wakeup mode support.
213 * Wakeup mode lets this IRQ wake the system from sleep
214 * states like "suspend to RAM".
216 int set_irq_wake(unsigned int irq
, unsigned int on
)
218 struct irq_desc
*desc
= irq_desc
+ irq
;
221 int (*set_wake
)(unsigned, unsigned) = desc
->chip
->set_wake
;
223 /* wakeup-capable irqs can be shared between drivers that
224 * don't need to have the same sleep mode behaviors.
226 spin_lock_irqsave(&desc
->lock
, flags
);
228 if (desc
->wake_depth
++ == 0)
229 desc
->status
|= IRQ_WAKEUP
;
233 if (desc
->wake_depth
== 0) {
234 printk(KERN_WARNING
"Unbalanced IRQ %d "
235 "wake disable\n", irq
);
237 } else if (--desc
->wake_depth
== 0)
238 desc
->status
&= ~IRQ_WAKEUP
;
243 ret
= desc
->chip
->set_wake(irq
, on
);
244 spin_unlock_irqrestore(&desc
->lock
, flags
);
247 EXPORT_SYMBOL(set_irq_wake
);
250 * Internal function that tells the architecture code whether a
251 * particular irq has been exclusively allocated or is available
254 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
256 struct irqaction
*action
;
258 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
261 action
= irq_desc
[irq
].action
;
263 if (irqflags
& action
->flags
& IRQF_SHARED
)
269 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
272 * If the architecture still has not overriden
273 * the flow handler then zap the default. This
274 * should catch incorrect flow-type setting.
276 if (desc
->handle_irq
== &handle_bad_irq
)
277 desc
->handle_irq
= NULL
;
281 * Internal function to register an irqaction - typically used to
282 * allocate special interrupts that are part of the architecture.
284 int setup_irq(unsigned int irq
, struct irqaction
*new)
286 struct irq_desc
*desc
= irq_desc
+ irq
;
287 struct irqaction
*old
, **p
;
288 const char *old_name
= NULL
;
295 if (desc
->chip
== &no_irq_chip
)
298 * Some drivers like serial.c use request_irq() heavily,
299 * so we have to be careful not to interfere with a
302 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
304 * This function might sleep, we want to call it first,
305 * outside of the atomic block.
306 * Yes, this might clear the entropy pool if the wrong
307 * driver is attempted to be loaded, without actually
308 * installing a new handler, but is this really a problem,
309 * only the sysadmin is able to do this.
311 rand_initialize_irq(irq
);
315 * The following block of code has to be executed atomically
317 spin_lock_irqsave(&desc
->lock
, flags
);
322 * Can't share interrupts unless both agree to and are
323 * the same type (level, edge, polarity). So both flag
324 * fields must have IRQF_SHARED set and the bits which
325 * set the trigger type must match.
327 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
328 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
329 old_name
= old
->name
;
333 #if defined(CONFIG_IRQ_PER_CPU)
334 /* All handlers must agree on per-cpuness */
335 if ((old
->flags
& IRQF_PERCPU
) !=
336 (new->flags
& IRQF_PERCPU
))
340 /* add new interrupt at end of irq queue */
350 /* Exclude IRQ from balancing */
351 if (new->flags
& IRQF_NOBALANCING
)
352 desc
->status
|= IRQ_NO_BALANCING
;
355 irq_chip_set_defaults(desc
->chip
);
357 #if defined(CONFIG_IRQ_PER_CPU)
358 if (new->flags
& IRQF_PERCPU
)
359 desc
->status
|= IRQ_PER_CPU
;
362 /* Setup the type (level, edge polarity) if configured: */
363 if (new->flags
& IRQF_TRIGGER_MASK
) {
364 if (desc
->chip
&& desc
->chip
->set_type
)
365 desc
->chip
->set_type(irq
,
366 new->flags
& IRQF_TRIGGER_MASK
);
369 * IRQF_TRIGGER_* but the PIC does not support
370 * multiple flow-types?
372 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
373 "function for IRQ %d (%s)\n", irq
,
374 desc
->chip
? desc
->chip
->name
:
377 compat_irq_chip_set_default_handler(desc
);
379 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
380 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
382 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
384 desc
->status
&= ~IRQ_DISABLED
;
385 if (desc
->chip
->startup
)
386 desc
->chip
->startup(irq
);
388 desc
->chip
->enable(irq
);
390 /* Undo nested disables: */
393 /* Reset broken irq detection when installing new handler */
395 desc
->irqs_unhandled
= 0;
398 * Check whether we disabled the irq via the spurious handler
399 * before. Reenable it and give it another chance.
401 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
402 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
403 __enable_irq(desc
, irq
);
406 spin_unlock_irqrestore(&desc
->lock
, flags
);
409 register_irq_proc(irq
);
411 register_handler_proc(irq
, new);
416 #ifdef CONFIG_DEBUG_SHIRQ
417 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
418 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
420 printk(KERN_ERR
"current handler: %s\n", old_name
);
424 spin_unlock_irqrestore(&desc
->lock
, flags
);
429 * free_irq - free an interrupt
430 * @irq: Interrupt line to free
431 * @dev_id: Device identity to free
433 * Remove an interrupt handler. The handler is removed and if the
434 * interrupt line is no longer in use by any driver it is disabled.
435 * On a shared IRQ the caller must ensure the interrupt is disabled
436 * on the card it drives before calling this function. The function
437 * does not return until any executing interrupts for this IRQ
440 * This function must not be called from interrupt context.
442 void free_irq(unsigned int irq
, void *dev_id
)
444 struct irq_desc
*desc
;
445 struct irqaction
**p
;
448 WARN_ON(in_interrupt());
452 desc
= irq_desc
+ irq
;
453 spin_lock_irqsave(&desc
->lock
, flags
);
456 struct irqaction
*action
= *p
;
459 struct irqaction
**pp
= p
;
462 if (action
->dev_id
!= dev_id
)
465 /* Found it - now remove it from the list of entries */
468 /* Currently used only by UML, might disappear one day.*/
469 #ifdef CONFIG_IRQ_RELEASE_METHOD
470 if (desc
->chip
->release
)
471 desc
->chip
->release(irq
, dev_id
);
475 desc
->status
|= IRQ_DISABLED
;
476 if (desc
->chip
->shutdown
)
477 desc
->chip
->shutdown(irq
);
479 desc
->chip
->disable(irq
);
481 spin_unlock_irqrestore(&desc
->lock
, flags
);
482 unregister_handler_proc(irq
, action
);
484 /* Make sure it's not being used on another CPU */
485 synchronize_irq(irq
);
486 #ifdef CONFIG_DEBUG_SHIRQ
488 * It's a shared IRQ -- the driver ought to be
489 * prepared for it to happen even now it's
490 * being freed, so let's make sure.... We do
491 * this after actually deregistering it, to
492 * make sure that a 'real' IRQ doesn't run in
493 * parallel with our fake
495 if (action
->flags
& IRQF_SHARED
) {
496 local_irq_save(flags
);
497 action
->handler(irq
, dev_id
);
498 local_irq_restore(flags
);
504 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
505 #ifdef CONFIG_DEBUG_SHIRQ
508 spin_unlock_irqrestore(&desc
->lock
, flags
);
512 EXPORT_SYMBOL(free_irq
);
515 * request_irq - allocate an interrupt line
516 * @irq: Interrupt line to allocate
517 * @handler: Function to be called when the IRQ occurs
518 * @irqflags: Interrupt type flags
519 * @devname: An ascii name for the claiming device
520 * @dev_id: A cookie passed back to the handler function
522 * This call allocates interrupt resources and enables the
523 * interrupt line and IRQ handling. From the point this
524 * call is made your handler function may be invoked. Since
525 * your handler function must clear any interrupt the board
526 * raises, you must take care both to initialise your hardware
527 * and to set up the interrupt handler in the right order.
529 * Dev_id must be globally unique. Normally the address of the
530 * device data structure is used as the cookie. Since the handler
531 * receives this value it makes sense to use it.
533 * If your interrupt is shared you must pass a non NULL dev_id
534 * as this is required when freeing the interrupt.
538 * IRQF_SHARED Interrupt is shared
539 * IRQF_DISABLED Disable local interrupts while processing
540 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
543 int request_irq(unsigned int irq
, irq_handler_t handler
,
544 unsigned long irqflags
, const char *devname
, void *dev_id
)
546 struct irqaction
*action
;
549 #ifdef CONFIG_LOCKDEP
551 * Lockdep wants atomic interrupt handlers:
553 irqflags
|= IRQF_DISABLED
;
556 * Sanity-check: shared interrupts must pass in a real dev-ID,
557 * otherwise we'll have trouble later trying to figure out
558 * which interrupt is which (messes up the interrupt freeing
561 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
565 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
570 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
574 action
->handler
= handler
;
575 action
->flags
= irqflags
;
576 cpus_clear(action
->mask
);
577 action
->name
= devname
;
579 action
->dev_id
= dev_id
;
581 select_smp_affinity(irq
);
583 #ifdef CONFIG_DEBUG_SHIRQ
584 if (irqflags
& IRQF_SHARED
) {
586 * It's a shared IRQ -- the driver ought to be prepared for it
587 * to happen immediately, so let's make sure....
588 * We do this before actually registering it, to make sure that
589 * a 'real' IRQ doesn't run in parallel with our fake
593 local_irq_save(flags
);
594 handler(irq
, dev_id
);
595 local_irq_restore(flags
);
599 retval
= setup_irq(irq
, action
);
605 EXPORT_SYMBOL(request_irq
);