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
);
44 * disable_irq_nosync - disable an irq without waiting
45 * @irq: Interrupt to disable
47 * Disable the selected interrupt line. Disables and Enables are
49 * Unlike disable_irq(), this function does not ensure existing
50 * instances of the IRQ handler have completed before returning.
52 * This function may be called from IRQ context.
54 void disable_irq_nosync(unsigned int irq
)
56 struct irq_desc
*desc
= irq_desc
+ irq
;
62 spin_lock_irqsave(&desc
->lock
, flags
);
64 desc
->status
|= IRQ_DISABLED
;
65 desc
->chip
->disable(irq
);
67 spin_unlock_irqrestore(&desc
->lock
, flags
);
69 EXPORT_SYMBOL(disable_irq_nosync
);
72 * disable_irq - disable an irq and wait for completion
73 * @irq: Interrupt to disable
75 * Disable the selected interrupt line. Enables and Disables are
77 * This function waits for any pending IRQ handlers for this interrupt
78 * to complete before returning. If you use this function while
79 * holding a resource the IRQ handler may need you will deadlock.
81 * This function may be called - with care - from IRQ context.
83 void disable_irq(unsigned int irq
)
85 struct irq_desc
*desc
= irq_desc
+ irq
;
90 disable_irq_nosync(irq
);
94 EXPORT_SYMBOL(disable_irq
);
97 * enable_irq - enable handling of an irq
98 * @irq: Interrupt to enable
100 * Undoes the effect of one call to disable_irq(). If this
101 * matches the last disable, processing of interrupts on this
102 * IRQ line is re-enabled.
104 * This function may be called from IRQ context.
106 void enable_irq(unsigned int irq
)
108 struct irq_desc
*desc
= irq_desc
+ irq
;
114 spin_lock_irqsave(&desc
->lock
, flags
);
115 switch (desc
->depth
) {
117 printk(KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
121 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
123 /* Prevent probing on this irq: */
124 desc
->status
= status
| IRQ_NOPROBE
;
125 check_irq_resend(desc
, irq
);
131 spin_unlock_irqrestore(&desc
->lock
, flags
);
133 EXPORT_SYMBOL(enable_irq
);
136 * set_irq_wake - control irq power management wakeup
137 * @irq: interrupt to control
138 * @on: enable/disable power management wakeup
140 * Enable/disable power management wakeup mode, which is
141 * disabled by default. Enables and disables must match,
142 * just as they match for non-wakeup mode support.
144 * Wakeup mode lets this IRQ wake the system from sleep
145 * states like "suspend to RAM".
147 int set_irq_wake(unsigned int irq
, unsigned int on
)
149 struct irq_desc
*desc
= irq_desc
+ irq
;
152 int (*set_wake
)(unsigned, unsigned) = desc
->chip
->set_wake
;
154 /* wakeup-capable irqs can be shared between drivers that
155 * don't need to have the same sleep mode behaviors.
157 spin_lock_irqsave(&desc
->lock
, flags
);
159 if (desc
->wake_depth
++ == 0)
160 desc
->status
|= IRQ_WAKEUP
;
164 if (desc
->wake_depth
== 0) {
165 printk(KERN_WARNING
"Unbalanced IRQ %d "
166 "wake disable\n", irq
);
168 } else if (--desc
->wake_depth
== 0)
169 desc
->status
&= ~IRQ_WAKEUP
;
174 ret
= desc
->chip
->set_wake(irq
, on
);
175 spin_unlock_irqrestore(&desc
->lock
, flags
);
178 EXPORT_SYMBOL(set_irq_wake
);
181 * Internal function that tells the architecture code whether a
182 * particular irq has been exclusively allocated or is available
185 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
187 struct irqaction
*action
;
189 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
192 action
= irq_desc
[irq
].action
;
194 if (irqflags
& action
->flags
& IRQF_SHARED
)
200 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
203 * If the architecture still has not overriden
204 * the flow handler then zap the default. This
205 * should catch incorrect flow-type setting.
207 if (desc
->handle_irq
== &handle_bad_irq
)
208 desc
->handle_irq
= NULL
;
212 * Internal function to register an irqaction - typically used to
213 * allocate special interrupts that are part of the architecture.
215 int setup_irq(unsigned int irq
, struct irqaction
*new)
217 struct irq_desc
*desc
= irq_desc
+ irq
;
218 struct irqaction
*old
, **p
;
219 const char *old_name
= NULL
;
226 if (desc
->chip
== &no_irq_chip
)
229 * Some drivers like serial.c use request_irq() heavily,
230 * so we have to be careful not to interfere with a
233 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
235 * This function might sleep, we want to call it first,
236 * outside of the atomic block.
237 * Yes, this might clear the entropy pool if the wrong
238 * driver is attempted to be loaded, without actually
239 * installing a new handler, but is this really a problem,
240 * only the sysadmin is able to do this.
242 rand_initialize_irq(irq
);
246 * The following block of code has to be executed atomically
248 spin_lock_irqsave(&desc
->lock
, flags
);
253 * Can't share interrupts unless both agree to and are
254 * the same type (level, edge, polarity). So both flag
255 * fields must have IRQF_SHARED set and the bits which
256 * set the trigger type must match.
258 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
259 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
260 old_name
= old
->name
;
264 #if defined(CONFIG_IRQ_PER_CPU)
265 /* All handlers must agree on per-cpuness */
266 if ((old
->flags
& IRQF_PERCPU
) !=
267 (new->flags
& IRQF_PERCPU
))
271 /* add new interrupt at end of irq queue */
280 #if defined(CONFIG_IRQ_PER_CPU)
281 if (new->flags
& IRQF_PERCPU
)
282 desc
->status
|= IRQ_PER_CPU
;
285 irq_chip_set_defaults(desc
->chip
);
287 /* Setup the type (level, edge polarity) if configured: */
288 if (new->flags
& IRQF_TRIGGER_MASK
) {
289 if (desc
->chip
&& desc
->chip
->set_type
)
290 desc
->chip
->set_type(irq
,
291 new->flags
& IRQF_TRIGGER_MASK
);
294 * IRQF_TRIGGER_* but the PIC does not support
295 * multiple flow-types?
297 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
298 "function for IRQ %d (%s)\n", irq
,
299 desc
->chip
? desc
->chip
->name
:
302 compat_irq_chip_set_default_handler(desc
);
304 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
307 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
309 desc
->status
&= ~IRQ_DISABLED
;
310 if (desc
->chip
->startup
)
311 desc
->chip
->startup(irq
);
313 desc
->chip
->enable(irq
);
315 /* Undo nested disables: */
318 /* Reset broken irq detection when installing new handler */
320 desc
->irqs_unhandled
= 0;
321 spin_unlock_irqrestore(&desc
->lock
, flags
);
324 register_irq_proc(irq
);
326 register_handler_proc(irq
, new);
331 #ifdef CONFIG_DEBUG_SHIRQ
332 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
333 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
335 printk(KERN_ERR
"current handler: %s\n", old_name
);
339 spin_unlock_irqrestore(&desc
->lock
, flags
);
344 * free_irq - free an interrupt
345 * @irq: Interrupt line to free
346 * @dev_id: Device identity to free
348 * Remove an interrupt handler. The handler is removed and if the
349 * interrupt line is no longer in use by any driver it is disabled.
350 * On a shared IRQ the caller must ensure the interrupt is disabled
351 * on the card it drives before calling this function. The function
352 * does not return until any executing interrupts for this IRQ
355 * This function must not be called from interrupt context.
357 void free_irq(unsigned int irq
, void *dev_id
)
359 struct irq_desc
*desc
;
360 struct irqaction
**p
;
362 irqreturn_t (*handler
)(int, void *) = NULL
;
364 WARN_ON(in_interrupt());
368 desc
= irq_desc
+ irq
;
369 spin_lock_irqsave(&desc
->lock
, flags
);
372 struct irqaction
*action
= *p
;
375 struct irqaction
**pp
= p
;
378 if (action
->dev_id
!= dev_id
)
381 /* Found it - now remove it from the list of entries */
384 /* Currently used only by UML, might disappear one day.*/
385 #ifdef CONFIG_IRQ_RELEASE_METHOD
386 if (desc
->chip
->release
)
387 desc
->chip
->release(irq
, dev_id
);
391 desc
->status
|= IRQ_DISABLED
;
392 if (desc
->chip
->shutdown
)
393 desc
->chip
->shutdown(irq
);
395 desc
->chip
->disable(irq
);
397 spin_unlock_irqrestore(&desc
->lock
, flags
);
398 unregister_handler_proc(irq
, action
);
400 /* Make sure it's not being used on another CPU */
401 synchronize_irq(irq
);
402 if (action
->flags
& IRQF_SHARED
)
403 handler
= action
->handler
;
407 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
408 spin_unlock_irqrestore(&desc
->lock
, flags
);
411 #ifdef CONFIG_DEBUG_SHIRQ
414 * It's a shared IRQ -- the driver ought to be prepared for it
415 * to happen even now it's being freed, so let's make sure....
416 * We do this after actually deregistering it, to make sure that
417 * a 'real' IRQ doesn't run in parallel with our fake
419 handler(irq
, dev_id
);
423 EXPORT_SYMBOL(free_irq
);
426 * request_irq - allocate an interrupt line
427 * @irq: Interrupt line to allocate
428 * @handler: Function to be called when the IRQ occurs
429 * @irqflags: Interrupt type flags
430 * @devname: An ascii name for the claiming device
431 * @dev_id: A cookie passed back to the handler function
433 * This call allocates interrupt resources and enables the
434 * interrupt line and IRQ handling. From the point this
435 * call is made your handler function may be invoked. Since
436 * your handler function must clear any interrupt the board
437 * raises, you must take care both to initialise your hardware
438 * and to set up the interrupt handler in the right order.
440 * Dev_id must be globally unique. Normally the address of the
441 * device data structure is used as the cookie. Since the handler
442 * receives this value it makes sense to use it.
444 * If your interrupt is shared you must pass a non NULL dev_id
445 * as this is required when freeing the interrupt.
449 * IRQF_SHARED Interrupt is shared
450 * IRQF_DISABLED Disable local interrupts while processing
451 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
454 int request_irq(unsigned int irq
, irq_handler_t handler
,
455 unsigned long irqflags
, const char *devname
, void *dev_id
)
457 struct irqaction
*action
;
460 #ifdef CONFIG_LOCKDEP
462 * Lockdep wants atomic interrupt handlers:
464 irqflags
|= IRQF_DISABLED
;
467 * Sanity-check: shared interrupts must pass in a real dev-ID,
468 * otherwise we'll have trouble later trying to figure out
469 * which interrupt is which (messes up the interrupt freeing
472 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
476 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
481 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
485 action
->handler
= handler
;
486 action
->flags
= irqflags
;
487 cpus_clear(action
->mask
);
488 action
->name
= devname
;
490 action
->dev_id
= dev_id
;
492 select_smp_affinity(irq
);
494 #ifdef CONFIG_DEBUG_SHIRQ
495 if (irqflags
& IRQF_SHARED
) {
497 * It's a shared IRQ -- the driver ought to be prepared for it
498 * to happen immediately, so let's make sure....
499 * We do this before actually registering it, to make sure that
500 * a 'real' IRQ doesn't run in parallel with our fake
502 if (irqflags
& IRQF_DISABLED
) {
505 local_irq_save(flags
);
506 handler(irq
, dev_id
);
507 local_irq_restore(flags
);
509 handler(irq
, dev_id
);
513 retval
= setup_irq(irq
, action
);
519 EXPORT_SYMBOL(request_irq
);