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 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
)
115 if (!irq_can_set_affinity(irq
))
118 cpus_and(mask
, cpu_online_map
, irq_default_affinity
);
120 irq_desc
[irq
].affinity
= mask
;
121 irq_desc
[irq
].chip
->set_affinity(irq
, mask
);
123 set_balance_irq_affinity(irq
, mask
);
131 * disable_irq_nosync - disable an irq without waiting
132 * @irq: Interrupt to disable
134 * Disable the selected interrupt line. Disables and Enables are
136 * Unlike disable_irq(), this function does not ensure existing
137 * instances of the IRQ handler have completed before returning.
139 * This function may be called from IRQ context.
141 void disable_irq_nosync(unsigned int irq
)
143 struct irq_desc
*desc
= irq_desc
+ irq
;
149 spin_lock_irqsave(&desc
->lock
, flags
);
150 if (!desc
->depth
++) {
151 desc
->status
|= IRQ_DISABLED
;
152 desc
->chip
->disable(irq
);
154 spin_unlock_irqrestore(&desc
->lock
, flags
);
156 EXPORT_SYMBOL(disable_irq_nosync
);
159 * disable_irq - disable an irq and wait for completion
160 * @irq: Interrupt to disable
162 * Disable the selected interrupt line. Enables and Disables are
164 * This function waits for any pending IRQ handlers for this interrupt
165 * to complete before returning. If you use this function while
166 * holding a resource the IRQ handler may need you will deadlock.
168 * This function may be called - with care - from IRQ context.
170 void disable_irq(unsigned int irq
)
172 struct irq_desc
*desc
= irq_desc
+ irq
;
177 disable_irq_nosync(irq
);
179 synchronize_irq(irq
);
181 EXPORT_SYMBOL(disable_irq
);
183 static void __enable_irq(struct irq_desc
*desc
, unsigned int irq
)
185 switch (desc
->depth
) {
187 WARN(1, KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
190 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
192 /* Prevent probing on this irq: */
193 desc
->status
= status
| IRQ_NOPROBE
;
194 check_irq_resend(desc
, irq
);
203 * enable_irq - enable handling of an irq
204 * @irq: Interrupt to enable
206 * Undoes the effect of one call to disable_irq(). If this
207 * matches the last disable, processing of interrupts on this
208 * IRQ line is re-enabled.
210 * This function may be called from IRQ context.
212 void enable_irq(unsigned int irq
)
214 struct irq_desc
*desc
= irq_desc
+ irq
;
220 spin_lock_irqsave(&desc
->lock
, flags
);
221 __enable_irq(desc
, irq
);
222 spin_unlock_irqrestore(&desc
->lock
, flags
);
224 EXPORT_SYMBOL(enable_irq
);
226 int set_irq_wake_real(unsigned int irq
, unsigned int on
)
228 struct irq_desc
*desc
= irq_desc
+ irq
;
231 if (desc
->chip
->set_wake
)
232 ret
= desc
->chip
->set_wake(irq
, on
);
238 * set_irq_wake - control irq power management wakeup
239 * @irq: interrupt to control
240 * @on: enable/disable power management wakeup
242 * Enable/disable power management wakeup mode, which is
243 * disabled by default. Enables and disables must match,
244 * just as they match for non-wakeup mode support.
246 * Wakeup mode lets this IRQ wake the system from sleep
247 * states like "suspend to RAM".
249 int set_irq_wake(unsigned int irq
, unsigned int on
)
251 struct irq_desc
*desc
= irq_desc
+ irq
;
255 /* wakeup-capable irqs can be shared between drivers that
256 * don't need to have the same sleep mode behaviors.
258 spin_lock_irqsave(&desc
->lock
, flags
);
260 if (desc
->wake_depth
++ == 0) {
261 ret
= set_irq_wake_real(irq
, on
);
263 desc
->wake_depth
= 0;
265 desc
->status
|= IRQ_WAKEUP
;
268 if (desc
->wake_depth
== 0) {
269 WARN(1, "Unbalanced IRQ %d wake disable\n", irq
);
270 } else if (--desc
->wake_depth
== 0) {
271 ret
= set_irq_wake_real(irq
, on
);
273 desc
->wake_depth
= 1;
275 desc
->status
&= ~IRQ_WAKEUP
;
279 spin_unlock_irqrestore(&desc
->lock
, flags
);
282 EXPORT_SYMBOL(set_irq_wake
);
285 * Internal function that tells the architecture code whether a
286 * particular irq has been exclusively allocated or is available
289 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
291 struct irqaction
*action
;
293 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
296 action
= irq_desc
[irq
].action
;
298 if (irqflags
& action
->flags
& IRQF_SHARED
)
304 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
307 * If the architecture still has not overriden
308 * the flow handler then zap the default. This
309 * should catch incorrect flow-type setting.
311 if (desc
->handle_irq
== &handle_bad_irq
)
312 desc
->handle_irq
= NULL
;
315 static int __irq_set_trigger(struct irq_chip
*chip
, unsigned int irq
,
320 if (!chip
|| !chip
->set_type
) {
322 * IRQF_TRIGGER_* but the PIC does not support multiple
325 pr_warning("No set_type function for IRQ %d (%s)\n", irq
,
326 chip
? (chip
->name
? : "unknown") : "unknown");
330 ret
= chip
->set_type(irq
, flags
& IRQF_TRIGGER_MASK
);
333 pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
334 (int)(flags
& IRQF_TRIGGER_MASK
),
335 irq
, chip
->set_type
);
341 * Internal function to register an irqaction - typically used to
342 * allocate special interrupts that are part of the architecture.
344 int setup_irq(unsigned int irq
, struct irqaction
*new)
346 struct irq_desc
*desc
= irq_desc
+ irq
;
347 struct irqaction
*old
, **p
;
348 const char *old_name
= NULL
;
356 if (desc
->chip
== &no_irq_chip
)
359 * Some drivers like serial.c use request_irq() heavily,
360 * so we have to be careful not to interfere with a
363 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
365 * This function might sleep, we want to call it first,
366 * outside of the atomic block.
367 * Yes, this might clear the entropy pool if the wrong
368 * driver is attempted to be loaded, without actually
369 * installing a new handler, but is this really a problem,
370 * only the sysadmin is able to do this.
372 rand_initialize_irq(irq
);
376 * The following block of code has to be executed atomically
378 spin_lock_irqsave(&desc
->lock
, flags
);
383 * Can't share interrupts unless both agree to and are
384 * the same type (level, edge, polarity). So both flag
385 * fields must have IRQF_SHARED set and the bits which
386 * set the trigger type must match.
388 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
389 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
390 old_name
= old
->name
;
394 #if defined(CONFIG_IRQ_PER_CPU)
395 /* All handlers must agree on per-cpuness */
396 if ((old
->flags
& IRQF_PERCPU
) !=
397 (new->flags
& IRQF_PERCPU
))
401 /* add new interrupt at end of irq queue */
410 irq_chip_set_defaults(desc
->chip
);
412 /* Setup the type (level, edge polarity) if configured: */
413 if (new->flags
& IRQF_TRIGGER_MASK
) {
414 ret
= __irq_set_trigger(desc
->chip
, irq
, new->flags
);
417 spin_unlock_irqrestore(&desc
->lock
, flags
);
421 compat_irq_chip_set_default_handler(desc
);
422 #if defined(CONFIG_IRQ_PER_CPU)
423 if (new->flags
& IRQF_PERCPU
)
424 desc
->status
|= IRQ_PER_CPU
;
427 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
428 IRQ_INPROGRESS
| IRQ_SPURIOUS_DISABLED
);
430 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
432 desc
->status
&= ~IRQ_DISABLED
;
433 if (desc
->chip
->startup
)
434 desc
->chip
->startup(irq
);
436 desc
->chip
->enable(irq
);
438 /* Undo nested disables: */
441 /* Set default affinity mask once everything is setup */
442 irq_select_affinity(irq
);
447 /* Exclude IRQ from balancing */
448 if (new->flags
& IRQF_NOBALANCING
)
449 desc
->status
|= IRQ_NO_BALANCING
;
451 /* Reset broken irq detection when installing new handler */
453 desc
->irqs_unhandled
= 0;
456 * Check whether we disabled the irq via the spurious handler
457 * before. Reenable it and give it another chance.
459 if (shared
&& (desc
->status
& IRQ_SPURIOUS_DISABLED
)) {
460 desc
->status
&= ~IRQ_SPURIOUS_DISABLED
;
461 __enable_irq(desc
, irq
);
464 spin_unlock_irqrestore(&desc
->lock
, flags
);
467 register_irq_proc(irq
);
469 register_handler_proc(irq
, new);
474 #ifdef CONFIG_DEBUG_SHIRQ
475 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
476 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
478 printk(KERN_ERR
"current handler: %s\n", old_name
);
482 spin_unlock_irqrestore(&desc
->lock
, flags
);
487 * free_irq - free an interrupt
488 * @irq: Interrupt line to free
489 * @dev_id: Device identity to free
491 * Remove an interrupt handler. The handler is removed and if the
492 * interrupt line is no longer in use by any driver it is disabled.
493 * On a shared IRQ the caller must ensure the interrupt is disabled
494 * on the card it drives before calling this function. The function
495 * does not return until any executing interrupts for this IRQ
498 * This function must not be called from interrupt context.
500 void free_irq(unsigned int irq
, void *dev_id
)
502 struct irq_desc
*desc
;
503 struct irqaction
**p
;
506 WARN_ON(in_interrupt());
510 desc
= irq_desc
+ irq
;
511 spin_lock_irqsave(&desc
->lock
, flags
);
514 struct irqaction
*action
= *p
;
517 struct irqaction
**pp
= p
;
520 if (action
->dev_id
!= dev_id
)
523 /* Found it - now remove it from the list of entries */
526 /* Currently used only by UML, might disappear one day.*/
527 #ifdef CONFIG_IRQ_RELEASE_METHOD
528 if (desc
->chip
->release
)
529 desc
->chip
->release(irq
, dev_id
);
533 desc
->status
|= IRQ_DISABLED
;
534 if (desc
->chip
->shutdown
)
535 desc
->chip
->shutdown(irq
);
537 desc
->chip
->disable(irq
);
539 spin_unlock_irqrestore(&desc
->lock
, flags
);
540 unregister_handler_proc(irq
, action
);
542 /* Make sure it's not being used on another CPU */
543 synchronize_irq(irq
);
544 #ifdef CONFIG_DEBUG_SHIRQ
546 * It's a shared IRQ -- the driver ought to be
547 * prepared for it to happen even now it's
548 * being freed, so let's make sure.... We do
549 * this after actually deregistering it, to
550 * make sure that a 'real' IRQ doesn't run in
551 * parallel with our fake
553 if (action
->flags
& IRQF_SHARED
) {
554 local_irq_save(flags
);
555 action
->handler(irq
, dev_id
);
556 local_irq_restore(flags
);
562 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
563 #ifdef CONFIG_DEBUG_SHIRQ
566 spin_unlock_irqrestore(&desc
->lock
, flags
);
570 EXPORT_SYMBOL(free_irq
);
573 * request_irq - allocate an interrupt line
574 * @irq: Interrupt line to allocate
575 * @handler: Function to be called when the IRQ occurs
576 * @irqflags: Interrupt type flags
577 * @devname: An ascii name for the claiming device
578 * @dev_id: A cookie passed back to the handler function
580 * This call allocates interrupt resources and enables the
581 * interrupt line and IRQ handling. From the point this
582 * call is made your handler function may be invoked. Since
583 * your handler function must clear any interrupt the board
584 * raises, you must take care both to initialise your hardware
585 * and to set up the interrupt handler in the right order.
587 * Dev_id must be globally unique. Normally the address of the
588 * device data structure is used as the cookie. Since the handler
589 * receives this value it makes sense to use it.
591 * If your interrupt is shared you must pass a non NULL dev_id
592 * as this is required when freeing the interrupt.
596 * IRQF_SHARED Interrupt is shared
597 * IRQF_DISABLED Disable local interrupts while processing
598 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
601 int request_irq(unsigned int irq
, irq_handler_t handler
,
602 unsigned long irqflags
, const char *devname
, void *dev_id
)
604 struct irqaction
*action
;
607 #ifdef CONFIG_LOCKDEP
609 * Lockdep wants atomic interrupt handlers:
611 irqflags
|= IRQF_DISABLED
;
614 * Sanity-check: shared interrupts must pass in a real dev-ID,
615 * otherwise we'll have trouble later trying to figure out
616 * which interrupt is which (messes up the interrupt freeing
619 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
623 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
628 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
632 action
->handler
= handler
;
633 action
->flags
= irqflags
;
634 cpus_clear(action
->mask
);
635 action
->name
= devname
;
637 action
->dev_id
= dev_id
;
639 #ifdef CONFIG_DEBUG_SHIRQ
640 if (irqflags
& IRQF_SHARED
) {
642 * It's a shared IRQ -- the driver ought to be prepared for it
643 * to happen immediately, so let's make sure....
644 * We do this before actually registering it, to make sure that
645 * a 'real' IRQ doesn't run in parallel with our fake
649 local_irq_save(flags
);
650 handler(irq
, dev_id
);
651 local_irq_restore(flags
);
655 retval
= setup_irq(irq
, action
);
661 EXPORT_SYMBOL(request_irq
);