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>
15 #include "internals.h"
20 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
21 * @irq: interrupt number to wait for
23 * This function waits for any pending IRQ handlers for this interrupt
24 * to complete before returning. If you use this function while
25 * holding a resource the IRQ handler may need you will deadlock.
27 * This function may be called - with care - from IRQ context.
29 void synchronize_irq(unsigned int irq
)
31 struct irq_desc
*desc
= irq_desc
+ irq
;
36 while (desc
->status
& IRQ_INPROGRESS
)
39 EXPORT_SYMBOL(synchronize_irq
);
42 * irq_can_set_affinity - Check if the affinity of a given irq can be set
43 * @irq: Interrupt to check
46 int irq_can_set_affinity(unsigned int irq
)
48 struct irq_desc
*desc
= irq_desc
+ irq
;
50 if (CHECK_IRQ_PER_CPU(desc
->status
) || !desc
->chip
||
51 !desc
->chip
->set_affinity
)
58 * irq_set_affinity - Set the irq affinity of a given irq
59 * @irq: Interrupt to set affinity
63 int irq_set_affinity(unsigned int irq
, cpumask_t cpumask
)
65 struct irq_desc
*desc
= irq_desc
+ irq
;
67 if (!desc
->chip
->set_affinity
)
70 set_balance_irq_affinity(irq
, cpumask
);
72 #ifdef CONFIG_GENERIC_PENDING_IRQ
73 set_pending_irq(irq
, cpumask
);
75 desc
->affinity
= cpumask
;
76 desc
->chip
->set_affinity(irq
, cpumask
);
84 * disable_irq_nosync - disable an irq without waiting
85 * @irq: Interrupt to disable
87 * Disable the selected interrupt line. Disables and Enables are
89 * Unlike disable_irq(), this function does not ensure existing
90 * instances of the IRQ handler have completed before returning.
92 * This function may be called from IRQ context.
94 void disable_irq_nosync(unsigned int irq
)
96 struct irq_desc
*desc
= irq_desc
+ irq
;
102 spin_lock_irqsave(&desc
->lock
, flags
);
103 if (!desc
->depth
++) {
104 desc
->status
|= IRQ_DISABLED
;
105 desc
->chip
->disable(irq
);
107 spin_unlock_irqrestore(&desc
->lock
, flags
);
109 EXPORT_SYMBOL(disable_irq_nosync
);
112 * disable_irq - disable an irq and wait for completion
113 * @irq: Interrupt to disable
115 * Disable the selected interrupt line. Enables and Disables are
117 * This function waits for any pending IRQ handlers for this interrupt
118 * to complete before returning. If you use this function while
119 * holding a resource the IRQ handler may need you will deadlock.
121 * This function may be called - with care - from IRQ context.
123 void disable_irq(unsigned int irq
)
125 struct irq_desc
*desc
= irq_desc
+ irq
;
130 disable_irq_nosync(irq
);
132 synchronize_irq(irq
);
134 EXPORT_SYMBOL(disable_irq
);
137 * enable_irq - enable handling of an irq
138 * @irq: Interrupt to enable
140 * Undoes the effect of one call to disable_irq(). If this
141 * matches the last disable, processing of interrupts on this
142 * IRQ line is re-enabled.
144 * This function may be called from IRQ context.
146 void enable_irq(unsigned int irq
)
148 struct irq_desc
*desc
= irq_desc
+ irq
;
154 spin_lock_irqsave(&desc
->lock
, flags
);
155 switch (desc
->depth
) {
157 printk(KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
161 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
163 /* Prevent probing on this irq: */
164 desc
->status
= status
| IRQ_NOPROBE
;
165 check_irq_resend(desc
, irq
);
171 spin_unlock_irqrestore(&desc
->lock
, flags
);
173 EXPORT_SYMBOL(enable_irq
);
176 * set_irq_wake - control irq power management wakeup
177 * @irq: interrupt to control
178 * @on: enable/disable power management wakeup
180 * Enable/disable power management wakeup mode, which is
181 * disabled by default. Enables and disables must match,
182 * just as they match for non-wakeup mode support.
184 * Wakeup mode lets this IRQ wake the system from sleep
185 * states like "suspend to RAM".
187 int set_irq_wake(unsigned int irq
, unsigned int on
)
189 struct irq_desc
*desc
= irq_desc
+ irq
;
192 int (*set_wake
)(unsigned, unsigned) = desc
->chip
->set_wake
;
194 /* wakeup-capable irqs can be shared between drivers that
195 * don't need to have the same sleep mode behaviors.
197 spin_lock_irqsave(&desc
->lock
, flags
);
199 if (desc
->wake_depth
++ == 0)
200 desc
->status
|= IRQ_WAKEUP
;
204 if (desc
->wake_depth
== 0) {
205 printk(KERN_WARNING
"Unbalanced IRQ %d "
206 "wake disable\n", irq
);
208 } else if (--desc
->wake_depth
== 0)
209 desc
->status
&= ~IRQ_WAKEUP
;
214 ret
= desc
->chip
->set_wake(irq
, on
);
215 spin_unlock_irqrestore(&desc
->lock
, flags
);
218 EXPORT_SYMBOL(set_irq_wake
);
221 * Internal function that tells the architecture code whether a
222 * particular irq has been exclusively allocated or is available
225 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
227 struct irqaction
*action
;
229 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
232 action
= irq_desc
[irq
].action
;
234 if (irqflags
& action
->flags
& IRQF_SHARED
)
240 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
243 * If the architecture still has not overriden
244 * the flow handler then zap the default. This
245 * should catch incorrect flow-type setting.
247 if (desc
->handle_irq
== &handle_bad_irq
)
248 desc
->handle_irq
= NULL
;
252 * Internal function to register an irqaction - typically used to
253 * allocate special interrupts that are part of the architecture.
255 int setup_irq(unsigned int irq
, struct irqaction
*new)
257 struct irq_desc
*desc
= irq_desc
+ irq
;
258 struct irqaction
*old
, **p
;
259 const char *old_name
= NULL
;
266 if (desc
->chip
== &no_irq_chip
)
269 * Some drivers like serial.c use request_irq() heavily,
270 * so we have to be careful not to interfere with a
273 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
275 * This function might sleep, we want to call it first,
276 * outside of the atomic block.
277 * Yes, this might clear the entropy pool if the wrong
278 * driver is attempted to be loaded, without actually
279 * installing a new handler, but is this really a problem,
280 * only the sysadmin is able to do this.
282 rand_initialize_irq(irq
);
286 * The following block of code has to be executed atomically
288 spin_lock_irqsave(&desc
->lock
, flags
);
293 * Can't share interrupts unless both agree to and are
294 * the same type (level, edge, polarity). So both flag
295 * fields must have IRQF_SHARED set and the bits which
296 * set the trigger type must match.
298 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
299 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
300 old_name
= old
->name
;
304 #if defined(CONFIG_IRQ_PER_CPU)
305 /* All handlers must agree on per-cpuness */
306 if ((old
->flags
& IRQF_PERCPU
) !=
307 (new->flags
& IRQF_PERCPU
))
311 /* add new interrupt at end of irq queue */
321 /* Exclude IRQ from balancing */
322 if (new->flags
& IRQF_NOBALANCING
)
323 desc
->status
|= IRQ_NO_BALANCING
;
326 irq_chip_set_defaults(desc
->chip
);
328 #if defined(CONFIG_IRQ_PER_CPU)
329 if (new->flags
& IRQF_PERCPU
)
330 desc
->status
|= IRQ_PER_CPU
;
333 /* Setup the type (level, edge polarity) if configured: */
334 if (new->flags
& IRQF_TRIGGER_MASK
) {
335 if (desc
->chip
&& desc
->chip
->set_type
)
336 desc
->chip
->set_type(irq
,
337 new->flags
& IRQF_TRIGGER_MASK
);
340 * IRQF_TRIGGER_* but the PIC does not support
341 * multiple flow-types?
343 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
344 "function for IRQ %d (%s)\n", irq
,
345 desc
->chip
? desc
->chip
->name
:
348 compat_irq_chip_set_default_handler(desc
);
350 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
353 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
355 desc
->status
&= ~IRQ_DISABLED
;
356 if (desc
->chip
->startup
)
357 desc
->chip
->startup(irq
);
359 desc
->chip
->enable(irq
);
361 /* Undo nested disables: */
364 /* Reset broken irq detection when installing new handler */
366 desc
->irqs_unhandled
= 0;
367 spin_unlock_irqrestore(&desc
->lock
, flags
);
370 register_irq_proc(irq
);
372 register_handler_proc(irq
, new);
377 #ifdef CONFIG_DEBUG_SHIRQ
378 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
379 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
381 printk(KERN_ERR
"current handler: %s\n", old_name
);
385 spin_unlock_irqrestore(&desc
->lock
, flags
);
390 * free_irq - free an interrupt
391 * @irq: Interrupt line to free
392 * @dev_id: Device identity to free
394 * Remove an interrupt handler. The handler is removed and if the
395 * interrupt line is no longer in use by any driver it is disabled.
396 * On a shared IRQ the caller must ensure the interrupt is disabled
397 * on the card it drives before calling this function. The function
398 * does not return until any executing interrupts for this IRQ
401 * This function must not be called from interrupt context.
403 void free_irq(unsigned int irq
, void *dev_id
)
405 struct irq_desc
*desc
;
406 struct irqaction
**p
;
408 irqreturn_t (*handler
)(int, void *) = NULL
;
410 WARN_ON(in_interrupt());
414 desc
= irq_desc
+ irq
;
415 spin_lock_irqsave(&desc
->lock
, flags
);
418 struct irqaction
*action
= *p
;
421 struct irqaction
**pp
= p
;
424 if (action
->dev_id
!= dev_id
)
427 /* Found it - now remove it from the list of entries */
430 /* Currently used only by UML, might disappear one day.*/
431 #ifdef CONFIG_IRQ_RELEASE_METHOD
432 if (desc
->chip
->release
)
433 desc
->chip
->release(irq
, dev_id
);
437 desc
->status
|= IRQ_DISABLED
;
438 if (desc
->chip
->shutdown
)
439 desc
->chip
->shutdown(irq
);
441 desc
->chip
->disable(irq
);
443 spin_unlock_irqrestore(&desc
->lock
, flags
);
444 unregister_handler_proc(irq
, action
);
446 /* Make sure it's not being used on another CPU */
447 synchronize_irq(irq
);
448 if (action
->flags
& IRQF_SHARED
)
449 handler
= action
->handler
;
453 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
454 spin_unlock_irqrestore(&desc
->lock
, flags
);
457 #ifdef CONFIG_DEBUG_SHIRQ
460 * It's a shared IRQ -- the driver ought to be prepared for it
461 * to happen even now it's being freed, so let's make sure....
462 * We do this after actually deregistering it, to make sure that
463 * a 'real' IRQ doesn't run in parallel with our fake
465 local_irq_save(flags
);
466 handler(irq
, dev_id
);
467 local_irq_restore(flags
);
471 EXPORT_SYMBOL(free_irq
);
474 * request_irq - allocate an interrupt line
475 * @irq: Interrupt line to allocate
476 * @handler: Function to be called when the IRQ occurs
477 * @irqflags: Interrupt type flags
478 * @devname: An ascii name for the claiming device
479 * @dev_id: A cookie passed back to the handler function
481 * This call allocates interrupt resources and enables the
482 * interrupt line and IRQ handling. From the point this
483 * call is made your handler function may be invoked. Since
484 * your handler function must clear any interrupt the board
485 * raises, you must take care both to initialise your hardware
486 * and to set up the interrupt handler in the right order.
488 * Dev_id must be globally unique. Normally the address of the
489 * device data structure is used as the cookie. Since the handler
490 * receives this value it makes sense to use it.
492 * If your interrupt is shared you must pass a non NULL dev_id
493 * as this is required when freeing the interrupt.
497 * IRQF_SHARED Interrupt is shared
498 * IRQF_DISABLED Disable local interrupts while processing
499 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
502 int request_irq(unsigned int irq
, irq_handler_t handler
,
503 unsigned long irqflags
, const char *devname
, void *dev_id
)
505 struct irqaction
*action
;
508 #ifdef CONFIG_LOCKDEP
510 * Lockdep wants atomic interrupt handlers:
512 irqflags
|= IRQF_DISABLED
;
515 * Sanity-check: shared interrupts must pass in a real dev-ID,
516 * otherwise we'll have trouble later trying to figure out
517 * which interrupt is which (messes up the interrupt freeing
520 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
524 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
529 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
533 action
->handler
= handler
;
534 action
->flags
= irqflags
;
535 cpus_clear(action
->mask
);
536 action
->name
= devname
;
538 action
->dev_id
= dev_id
;
540 select_smp_affinity(irq
);
542 #ifdef CONFIG_DEBUG_SHIRQ
543 if (irqflags
& IRQF_SHARED
) {
545 * It's a shared IRQ -- the driver ought to be prepared for it
546 * to happen immediately, so let's make sure....
547 * We do this before actually registering it, to make sure that
548 * a 'real' IRQ doesn't run in parallel with our fake
552 local_irq_save(flags
);
553 handler(irq
, dev_id
);
554 local_irq_restore(flags
);
558 retval
= setup_irq(irq
, action
);
564 EXPORT_SYMBOL(request_irq
);