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 printk(KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
184 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
186 /* Prevent probing on this irq: */
187 desc
->status
= status
| IRQ_NOPROBE
;
188 check_irq_resend(desc
, irq
);
197 * enable_irq - enable handling of an irq
198 * @irq: Interrupt to enable
200 * Undoes the effect of one call to disable_irq(). If this
201 * matches the last disable, processing of interrupts on this
202 * IRQ line is re-enabled.
204 * This function may be called from IRQ context.
206 void enable_irq(unsigned int irq
)
208 struct irq_desc
*desc
= irq_desc
+ irq
;
214 spin_lock_irqsave(&desc
->lock
, flags
);
215 __enable_irq(desc
, irq
);
216 spin_unlock_irqrestore(&desc
->lock
, flags
);
218 EXPORT_SYMBOL(enable_irq
);
221 * set_irq_wake - control irq power management wakeup
222 * @irq: interrupt to control
223 * @on: enable/disable power management wakeup
225 * Enable/disable power management wakeup mode, which is
226 * disabled by default. Enables and disables must match,
227 * just as they match for non-wakeup mode support.
229 * Wakeup mode lets this IRQ wake the system from sleep
230 * states like "suspend to RAM".
232 int set_irq_wake(unsigned int irq
, unsigned int on
)
234 struct irq_desc
*desc
= irq_desc
+ irq
;
237 int (*set_wake
)(unsigned, unsigned) = desc
->chip
->set_wake
;
239 /* wakeup-capable irqs can be shared between drivers that
240 * don't need to have the same sleep mode behaviors.
242 spin_lock_irqsave(&desc
->lock
, flags
);
244 if (desc
->wake_depth
++ == 0)
245 desc
->status
|= IRQ_WAKEUP
;
249 if (desc
->wake_depth
== 0) {
250 printk(KERN_WARNING
"Unbalanced IRQ %d "
251 "wake disable\n", irq
);
253 } else if (--desc
->wake_depth
== 0)
254 desc
->status
&= ~IRQ_WAKEUP
;
259 ret
= desc
->chip
->set_wake(irq
, on
);
260 spin_unlock_irqrestore(&desc
->lock
, flags
);
263 EXPORT_SYMBOL(set_irq_wake
);
266 * Internal function that tells the architecture code whether a
267 * particular irq has been exclusively allocated or is available
270 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
272 struct irqaction
*action
;
274 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
277 action
= irq_desc
[irq
].action
;
279 if (irqflags
& action
->flags
& IRQF_SHARED
)
285 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
288 * If the architecture still has not overriden
289 * the flow handler then zap the default. This
290 * should catch incorrect flow-type setting.
292 if (desc
->handle_irq
== &handle_bad_irq
)
293 desc
->handle_irq
= NULL
;
297 * Internal function to register an irqaction - typically used to
298 * allocate special interrupts that are part of the architecture.
300 int setup_irq(unsigned int irq
, struct irqaction
*new)
302 struct irq_desc
*desc
= irq_desc
+ irq
;
303 struct irqaction
*old
, **p
;
304 const char *old_name
= NULL
;
311 if (desc
->chip
== &no_irq_chip
)
314 * Some drivers like serial.c use request_irq() heavily,
315 * so we have to be careful not to interfere with a
318 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
320 * This function might sleep, we want to call it first,
321 * outside of the atomic block.
322 * Yes, this might clear the entropy pool if the wrong
323 * driver is attempted to be loaded, without actually
324 * installing a new handler, but is this really a problem,
325 * only the sysadmin is able to do this.
327 rand_initialize_irq(irq
);
331 * The following block of code has to be executed atomically
333 spin_lock_irqsave(&desc
->lock
, flags
);
338 * Can't share interrupts unless both agree to and are
339 * the same type (level, edge, polarity). So both flag
340 * fields must have IRQF_SHARED set and the bits which
341 * set the trigger type must match.
343 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
344 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
345 old_name
= old
->name
;
349 #if defined(CONFIG_IRQ_PER_CPU)
350 /* All handlers must agree on per-cpuness */
351 if ((old
->flags
& IRQF_PERCPU
) !=
352 (new->flags
& IRQF_PERCPU
))
356 /* add new interrupt at end of irq queue */
366 /* Exclude IRQ from balancing */
367 if (new->flags
& IRQF_NOBALANCING
)
368 desc
->status
|= IRQ_NO_BALANCING
;
371 irq_chip_set_defaults(desc
->chip
);
373 #if defined(CONFIG_IRQ_PER_CPU)
374 if (new->flags
& IRQF_PERCPU
)
375 desc
->status
|= IRQ_PER_CPU
;
378 /* Setup the type (level, edge polarity) if configured: */
379 if (new->flags
& IRQF_TRIGGER_MASK
) {
380 if (desc
->chip
->set_type
)
381 desc
->chip
->set_type(irq
,
382 new->flags
& IRQF_TRIGGER_MASK
);
385 * IRQF_TRIGGER_* but the PIC does not support
386 * multiple flow-types?
388 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
389 "function for IRQ %d (%s)\n", irq
,
392 compat_irq_chip_set_default_handler(desc
);
394 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
395 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
397 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
399 desc
->status
&= ~IRQ_DISABLED
;
400 if (desc
->chip
->startup
)
401 desc
->chip
->startup(irq
);
403 desc
->chip
->enable(irq
);
405 /* Undo nested disables: */
408 /* Set default affinity mask once everything is setup */
409 irq_select_affinity(irq
);
411 /* Reset broken irq detection when installing new handler */
413 desc
->irqs_unhandled
= 0;
416 * Check whether we disabled the irq via the spurious handler
417 * before. Reenable it and give it another chance.
419 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
420 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
421 __enable_irq(desc
, irq
);
424 spin_unlock_irqrestore(&desc
->lock
, flags
);
427 register_irq_proc(irq
);
429 register_handler_proc(irq
, new);
434 #ifdef CONFIG_DEBUG_SHIRQ
435 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
436 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
438 printk(KERN_ERR
"current handler: %s\n", old_name
);
442 spin_unlock_irqrestore(&desc
->lock
, flags
);
447 * free_irq - free an interrupt
448 * @irq: Interrupt line to free
449 * @dev_id: Device identity to free
451 * Remove an interrupt handler. The handler is removed and if the
452 * interrupt line is no longer in use by any driver it is disabled.
453 * On a shared IRQ the caller must ensure the interrupt is disabled
454 * on the card it drives before calling this function. The function
455 * does not return until any executing interrupts for this IRQ
458 * This function must not be called from interrupt context.
460 void free_irq(unsigned int irq
, void *dev_id
)
462 struct irq_desc
*desc
;
463 struct irqaction
**p
;
466 WARN_ON(in_interrupt());
470 desc
= irq_desc
+ irq
;
471 spin_lock_irqsave(&desc
->lock
, flags
);
474 struct irqaction
*action
= *p
;
477 struct irqaction
**pp
= p
;
480 if (action
->dev_id
!= dev_id
)
483 /* Found it - now remove it from the list of entries */
486 /* Currently used only by UML, might disappear one day.*/
487 #ifdef CONFIG_IRQ_RELEASE_METHOD
488 if (desc
->chip
->release
)
489 desc
->chip
->release(irq
, dev_id
);
493 desc
->status
|= IRQ_DISABLED
;
494 if (desc
->chip
->shutdown
)
495 desc
->chip
->shutdown(irq
);
497 desc
->chip
->disable(irq
);
499 spin_unlock_irqrestore(&desc
->lock
, flags
);
500 unregister_handler_proc(irq
, action
);
502 /* Make sure it's not being used on another CPU */
503 synchronize_irq(irq
);
504 #ifdef CONFIG_DEBUG_SHIRQ
506 * It's a shared IRQ -- the driver ought to be
507 * prepared for it to happen even now it's
508 * being freed, so let's make sure.... We do
509 * this after actually deregistering it, to
510 * make sure that a 'real' IRQ doesn't run in
511 * parallel with our fake
513 if (action
->flags
& IRQF_SHARED
) {
514 local_irq_save(flags
);
515 action
->handler(irq
, dev_id
);
516 local_irq_restore(flags
);
522 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
523 #ifdef CONFIG_DEBUG_SHIRQ
526 spin_unlock_irqrestore(&desc
->lock
, flags
);
530 EXPORT_SYMBOL(free_irq
);
533 * request_irq - allocate an interrupt line
534 * @irq: Interrupt line to allocate
535 * @handler: Function to be called when the IRQ occurs
536 * @irqflags: Interrupt type flags
537 * @devname: An ascii name for the claiming device
538 * @dev_id: A cookie passed back to the handler function
540 * This call allocates interrupt resources and enables the
541 * interrupt line and IRQ handling. From the point this
542 * call is made your handler function may be invoked. Since
543 * your handler function must clear any interrupt the board
544 * raises, you must take care both to initialise your hardware
545 * and to set up the interrupt handler in the right order.
547 * Dev_id must be globally unique. Normally the address of the
548 * device data structure is used as the cookie. Since the handler
549 * receives this value it makes sense to use it.
551 * If your interrupt is shared you must pass a non NULL dev_id
552 * as this is required when freeing the interrupt.
556 * IRQF_SHARED Interrupt is shared
557 * IRQF_DISABLED Disable local interrupts while processing
558 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
561 int request_irq(unsigned int irq
, irq_handler_t handler
,
562 unsigned long irqflags
, const char *devname
, void *dev_id
)
564 struct irqaction
*action
;
567 #ifdef CONFIG_LOCKDEP
569 * Lockdep wants atomic interrupt handlers:
571 irqflags
|= IRQF_DISABLED
;
574 * Sanity-check: shared interrupts must pass in a real dev-ID,
575 * otherwise we'll have trouble later trying to figure out
576 * which interrupt is which (messes up the interrupt freeing
579 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
583 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
588 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
592 action
->handler
= handler
;
593 action
->flags
= irqflags
;
594 cpus_clear(action
->mask
);
595 action
->name
= devname
;
597 action
->dev_id
= dev_id
;
599 #ifdef CONFIG_DEBUG_SHIRQ
600 if (irqflags
& IRQF_SHARED
) {
602 * It's a shared IRQ -- the driver ought to be prepared for it
603 * to happen immediately, so let's make sure....
604 * We do this before actually registering it, to make sure that
605 * a 'real' IRQ doesn't run in parallel with our fake
609 local_irq_save(flags
);
610 handler(irq
, dev_id
);
611 local_irq_restore(flags
);
615 retval
= setup_irq(irq
, action
);
621 EXPORT_SYMBOL(request_irq
);