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 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
191 unsigned int status = desc->status & ~IRQ_DISABLED;
193 /* Prevent probing on this irq: */
194 desc->status = status | IRQ_NOPROBE;
195 check_irq_resend(desc, irq);
204 * enable_irq - enable handling of an irq
205 * @irq: Interrupt to enable
207 * Undoes the effect of one call to disable_irq(). If this
208 * matches the last disable, processing of interrupts on this
209 * IRQ line is re-enabled.
211 * This function may be called from IRQ context.
213 void enable_irq(unsigned int irq)
215 struct irq_desc *desc = irq_desc + irq;
221 spin_lock_irqsave(&desc->lock, flags);
222 __enable_irq(desc, irq);
223 spin_unlock_irqrestore(&desc->lock, flags);
225 EXPORT_SYMBOL(enable_irq);
228 * set_irq_wake - control irq power management wakeup
229 * @irq: interrupt to control
230 * @on: enable/disable power management wakeup
232 * Enable/disable power management wakeup mode, which is
233 * disabled by default. Enables and disables must match,
234 * just as they match for non-wakeup mode support.
236 * Wakeup mode lets this IRQ wake the system from sleep
237 * states like "suspend to RAM".
239 int set_irq_wake(unsigned int irq, unsigned int on)
241 struct irq_desc *desc = irq_desc + irq;
244 int (*set_wake)(unsigned, unsigned) = desc->chip->set_wake;
246 /* wakeup-capable irqs can be shared between drivers that
247 * don't need to have the same sleep mode behaviors.
249 spin_lock_irqsave(&desc->lock, flags);
251 if (desc->wake_depth++ == 0)
252 desc->status |= IRQ_WAKEUP;
256 if (desc->wake_depth == 0) {
257 printk(KERN_WARNING "Unbalanced IRQ %d "
258 "wake disable\n", irq);
260 } else if (--desc->wake_depth == 0)
261 desc->status &= ~IRQ_WAKEUP;
266 ret = desc->chip->set_wake(irq, on);
267 spin_unlock_irqrestore(&desc->lock, flags);
270 EXPORT_SYMBOL(set_irq_wake);
273 * Internal function that tells the architecture code whether a
274 * particular irq has been exclusively allocated or is available
277 int can_request_irq(unsigned int irq, unsigned long irqflags)
279 struct irqaction *action;
281 if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
284 action = irq_desc[irq].action;
286 if (irqflags & action->flags & IRQF_SHARED)
292 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
295 * If the architecture still has not overriden
296 * the flow handler then zap the default. This
297 * should catch incorrect flow-type setting.
299 if (desc->handle_irq == &handle_bad_irq)
300 desc->handle_irq = NULL;
304 * Internal function to register an irqaction - typically used to
305 * allocate special interrupts that are part of the architecture.
307 int setup_irq(unsigned int irq, struct irqaction *new)
309 struct irq_desc *desc = irq_desc + irq;
310 struct irqaction *old, **p;
311 const char *old_name = NULL;
318 if (desc->chip == &no_irq_chip)
321 * Some drivers like serial.c use request_irq() heavily,
322 * so we have to be careful not to interfere with a
325 if (new->flags & IRQF_SAMPLE_RANDOM) {
327 * This function might sleep, we want to call it first,
328 * outside of the atomic block.
329 * Yes, this might clear the entropy pool if the wrong
330 * driver is attempted to be loaded, without actually
331 * installing a new handler, but is this really a problem,
332 * only the sysadmin is able to do this.
334 rand_initialize_irq(irq);
338 * The following block of code has to be executed atomically
340 spin_lock_irqsave(&desc->lock, flags);
345 * Can't share interrupts unless both agree to and are
346 * the same type (level, edge, polarity). So both flag
347 * fields must have IRQF_SHARED set and the bits which
348 * set the trigger type must match.
350 if (!((old->flags & new->flags) & IRQF_SHARED) ||
351 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
352 old_name = old->name;
356 #if defined(CONFIG_IRQ_PER_CPU)
357 /* All handlers must agree on per-cpuness */
358 if ((old->flags & IRQF_PERCPU) !=
359 (new->flags & IRQF_PERCPU))
363 /* add new interrupt at end of irq queue */
373 /* Exclude IRQ from balancing */
374 if (new->flags & IRQF_NOBALANCING)
375 desc->status |= IRQ_NO_BALANCING;
378 irq_chip_set_defaults(desc->chip);
380 #if defined(CONFIG_IRQ_PER_CPU)
381 if (new->flags & IRQF_PERCPU)
382 desc->status |= IRQ_PER_CPU;
385 /* Setup the type (level, edge polarity) if configured: */
386 if (new->flags & IRQF_TRIGGER_MASK) {
387 if (desc->chip->set_type)
388 desc->chip->set_type(irq,
389 new->flags & IRQF_TRIGGER_MASK);
392 * IRQF_TRIGGER_* but the PIC does not support
393 * multiple flow-types?
395 printk(KERN_WARNING "No IRQF_TRIGGER set_type "
396 "function for IRQ %d (%s)\n", irq,
399 compat_irq_chip_set_default_handler(desc);
401 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
402 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
404 if (!(desc->status & IRQ_NOAUTOEN)) {
406 desc->status &= ~IRQ_DISABLED;
407 if (desc->chip->startup)
408 desc->chip->startup(irq);
410 desc->chip->enable(irq);
412 /* Undo nested disables: */
415 /* Set default affinity mask once everything is setup */
416 irq_select_affinity(irq);
418 /* Reset broken irq detection when installing new handler */
420 desc->irqs_unhandled = 0;
423 * Check whether we disabled the irq via the spurious handler
424 * before. Reenable it and give it another chance.
426 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
427 desc->status &= ~IRQ_SPURIOUS_DISABLED;
428 __enable_irq(desc, irq);
431 spin_unlock_irqrestore(&desc->lock, flags);
434 register_irq_proc(irq);
436 register_handler_proc(irq, new);
441 #ifdef CONFIG_DEBUG_SHIRQ
442 if (!(new->flags & IRQF_PROBE_SHARED)) {
443 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
445 printk(KERN_ERR "current handler: %s\n", old_name);
449 spin_unlock_irqrestore(&desc->lock, flags);
454 * free_irq - free an interrupt
455 * @irq: Interrupt line to free
456 * @dev_id: Device identity to free
458 * Remove an interrupt handler. The handler is removed and if the
459 * interrupt line is no longer in use by any driver it is disabled.
460 * On a shared IRQ the caller must ensure the interrupt is disabled
461 * on the card it drives before calling this function. The function
462 * does not return until any executing interrupts for this IRQ
465 * This function must not be called from interrupt context.
467 void free_irq(unsigned int irq, void *dev_id)
469 struct irq_desc *desc;
470 struct irqaction **p;
473 WARN_ON(in_interrupt());
477 desc = irq_desc + irq;
478 spin_lock_irqsave(&desc->lock, flags);
481 struct irqaction *action = *p;
484 struct irqaction **pp = p;
487 if (action->dev_id != dev_id)
490 /* Found it - now remove it from the list of entries */
493 /* Currently used only by UML, might disappear one day.*/
494 #ifdef CONFIG_IRQ_RELEASE_METHOD
495 if (desc->chip->release)
496 desc->chip->release(irq, dev_id);
500 desc->status |= IRQ_DISABLED;
501 if (desc->chip->shutdown)
502 desc->chip->shutdown(irq);
504 desc->chip->disable(irq);
506 spin_unlock_irqrestore(&desc->lock, flags);
507 unregister_handler_proc(irq, action);
509 /* Make sure it's not being used on another CPU */
510 synchronize_irq(irq);
511 #ifdef CONFIG_DEBUG_SHIRQ
513 * It's a shared IRQ -- the driver ought to be
514 * prepared for it to happen even now it's
515 * being freed, so let's make sure.... We do
516 * this after actually deregistering it, to
517 * make sure that a 'real' IRQ doesn't run in
518 * parallel with our fake
520 if (action->flags & IRQF_SHARED) {
521 local_irq_save(flags);
522 action->handler(irq, dev_id);
523 local_irq_restore(flags);
529 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
530 #ifdef CONFIG_DEBUG_SHIRQ
533 spin_unlock_irqrestore(&desc->lock, flags);
537 EXPORT_SYMBOL(free_irq);
540 * request_irq - allocate an interrupt line
541 * @irq: Interrupt line to allocate
542 * @handler: Function to be called when the IRQ occurs
543 * @irqflags: Interrupt type flags
544 * @devname: An ascii name for the claiming device
545 * @dev_id: A cookie passed back to the handler function
547 * This call allocates interrupt resources and enables the
548 * interrupt line and IRQ handling. From the point this
549 * call is made your handler function may be invoked. Since
550 * your handler function must clear any interrupt the board
551 * raises, you must take care both to initialise your hardware
552 * and to set up the interrupt handler in the right order.
554 * Dev_id must be globally unique. Normally the address of the
555 * device data structure is used as the cookie. Since the handler
556 * receives this value it makes sense to use it.
558 * If your interrupt is shared you must pass a non NULL dev_id
559 * as this is required when freeing the interrupt.
563 * IRQF_SHARED Interrupt is shared
564 * IRQF_DISABLED Disable local interrupts while processing
565 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
568 int request_irq(unsigned int irq, irq_handler_t handler,
569 unsigned long irqflags, const char *devname, void *dev_id)
571 struct irqaction *action;
574 #ifdef CONFIG_LOCKDEP
576 * Lockdep wants atomic interrupt handlers:
578 irqflags |= IRQF_DISABLED;
581 * Sanity-check: shared interrupts must pass in a real dev-ID,
582 * otherwise we'll have trouble later trying to figure out
583 * which interrupt is which (messes up the interrupt freeing
586 if ((irqflags & IRQF_SHARED) && !dev_id)
590 if (irq_desc[irq].status & IRQ_NOREQUEST)
595 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
599 action->handler = handler;
600 action->flags = irqflags;
601 cpus_clear(action->mask);
602 action->name = devname;
604 action->dev_id = dev_id;
606 #ifdef CONFIG_DEBUG_SHIRQ
607 if (irqflags & IRQF_SHARED) {
609 * It's a shared IRQ -- the driver ought to be prepared for it
610 * to happen immediately, so let's make sure....
611 * We do this before actually registering it, to make sure that
612 * a 'real' IRQ doesn't run in parallel with our fake
616 local_irq_save(flags);
617 handler(irq, dev_id);
618 local_irq_restore(flags);
622 retval = setup_irq(irq, action);
628 EXPORT_SYMBOL(request_irq);