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 WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
183 unsigned int status = desc->status & ~IRQ_DISABLED;
185 /* Prevent probing on this irq: */
186 desc->status = status | IRQ_NOPROBE;
187 check_irq_resend(desc, irq);
196 * enable_irq - enable handling of an irq
197 * @irq: Interrupt to enable
199 * Undoes the effect of one call to disable_irq(). If this
200 * matches the last disable, processing of interrupts on this
201 * IRQ line is re-enabled.
203 * This function may be called from IRQ context.
205 void enable_irq(unsigned int irq)
207 struct irq_desc *desc = irq_desc + irq;
213 spin_lock_irqsave(&desc->lock, flags);
214 __enable_irq(desc, irq);
215 spin_unlock_irqrestore(&desc->lock, flags);
217 EXPORT_SYMBOL(enable_irq);
219 int set_irq_wake_real(unsigned int irq, unsigned int on)
221 struct irq_desc *desc = irq_desc + irq;
224 if (desc->chip->set_wake)
225 ret = desc->chip->set_wake(irq, on);
231 * set_irq_wake - control irq power management wakeup
232 * @irq: interrupt to control
233 * @on: enable/disable power management wakeup
235 * Enable/disable power management wakeup mode, which is
236 * disabled by default. Enables and disables must match,
237 * just as they match for non-wakeup mode support.
239 * Wakeup mode lets this IRQ wake the system from sleep
240 * states like "suspend to RAM".
242 int set_irq_wake(unsigned int irq, unsigned int on)
244 struct irq_desc *desc = irq_desc + irq;
248 /* wakeup-capable irqs can be shared between drivers that
249 * don't need to have the same sleep mode behaviors.
251 spin_lock_irqsave(&desc->lock, flags);
253 if (desc->wake_depth++ == 0) {
254 ret = set_irq_wake_real(irq, on);
256 desc->wake_depth = 0;
258 desc->status |= IRQ_WAKEUP;
261 if (desc->wake_depth == 0) {
262 WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
263 } else if (--desc->wake_depth == 0) {
264 ret = set_irq_wake_real(irq, on);
266 desc->wake_depth = 1;
268 desc->status &= ~IRQ_WAKEUP;
272 spin_unlock_irqrestore(&desc->lock, flags);
275 EXPORT_SYMBOL(set_irq_wake);
278 * Internal function that tells the architecture code whether a
279 * particular irq has been exclusively allocated or is available
282 int can_request_irq(unsigned int irq, unsigned long irqflags)
284 struct irqaction *action;
286 if (irq >= NR_IRQS || irq_desc[irq].status & IRQ_NOREQUEST)
289 action = irq_desc[irq].action;
291 if (irqflags & action->flags & IRQF_SHARED)
297 void compat_irq_chip_set_default_handler(struct irq_desc *desc)
300 * If the architecture still has not overriden
301 * the flow handler then zap the default. This
302 * should catch incorrect flow-type setting.
304 if (desc->handle_irq == &handle_bad_irq)
305 desc->handle_irq = NULL;
308 static int __irq_set_trigger(struct irq_chip *chip, unsigned int irq,
313 if (!chip || !chip->set_type) {
315 * IRQF_TRIGGER_* but the PIC does not support multiple
318 pr_warning("No set_type function for IRQ %d (%s)\n", irq,
319 chip ? (chip->name ? : "unknown") : "unknown");
323 ret = chip->set_type(irq, flags & IRQF_TRIGGER_MASK);
326 pr_err("setting flow type for irq %u failed (%pF)\n",
327 irq, chip->set_type);
333 * Internal function to register an irqaction - typically used to
334 * allocate special interrupts that are part of the architecture.
336 int setup_irq(unsigned int irq, struct irqaction *new)
338 struct irq_desc *desc = irq_desc + irq;
339 struct irqaction *old, **p;
340 const char *old_name = NULL;
348 if (desc->chip == &no_irq_chip)
351 * Some drivers like serial.c use request_irq() heavily,
352 * so we have to be careful not to interfere with a
355 if (new->flags & IRQF_SAMPLE_RANDOM) {
357 * This function might sleep, we want to call it first,
358 * outside of the atomic block.
359 * Yes, this might clear the entropy pool if the wrong
360 * driver is attempted to be loaded, without actually
361 * installing a new handler, but is this really a problem,
362 * only the sysadmin is able to do this.
364 rand_initialize_irq(irq);
368 * The following block of code has to be executed atomically
370 spin_lock_irqsave(&desc->lock, flags);
375 * Can't share interrupts unless both agree to and are
376 * the same type (level, edge, polarity). So both flag
377 * fields must have IRQF_SHARED set and the bits which
378 * set the trigger type must match.
380 if (!((old->flags & new->flags) & IRQF_SHARED) ||
381 ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
382 old_name = old->name;
386 #if defined(CONFIG_IRQ_PER_CPU)
387 /* All handlers must agree on per-cpuness */
388 if ((old->flags & IRQF_PERCPU) !=
389 (new->flags & IRQF_PERCPU))
393 /* add new interrupt at end of irq queue */
402 irq_chip_set_defaults(desc->chip);
404 /* Setup the type (level, edge polarity) if configured: */
405 if (new->flags & IRQF_TRIGGER_MASK) {
406 ret = __irq_set_trigger(desc->chip, irq, new->flags);
409 spin_unlock_irqrestore(&desc->lock, flags);
413 compat_irq_chip_set_default_handler(desc);
414 #if defined(CONFIG_IRQ_PER_CPU)
415 if (new->flags & IRQF_PERCPU)
416 desc->status |= IRQ_PER_CPU;
419 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
420 IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
422 if (!(desc->status & IRQ_NOAUTOEN)) {
424 desc->status &= ~IRQ_DISABLED;
425 if (desc->chip->startup)
426 desc->chip->startup(irq);
428 desc->chip->enable(irq);
430 /* Undo nested disables: */
433 /* Set default affinity mask once everything is setup */
434 irq_select_affinity(irq);
439 /* Exclude IRQ from balancing */
440 if (new->flags & IRQF_NOBALANCING)
441 desc->status |= IRQ_NO_BALANCING;
443 /* Reset broken irq detection when installing new handler */
445 desc->irqs_unhandled = 0;
448 * Check whether we disabled the irq via the spurious handler
449 * before. Reenable it and give it another chance.
451 if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
452 desc->status &= ~IRQ_SPURIOUS_DISABLED;
453 __enable_irq(desc, irq);
456 spin_unlock_irqrestore(&desc->lock, flags);
459 register_irq_proc(irq);
461 register_handler_proc(irq, new);
466 #ifdef CONFIG_DEBUG_SHIRQ
467 if (!(new->flags & IRQF_PROBE_SHARED)) {
468 printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
470 printk(KERN_ERR "current handler: %s\n", old_name);
474 spin_unlock_irqrestore(&desc->lock, flags);
479 * free_irq - free an interrupt
480 * @irq: Interrupt line to free
481 * @dev_id: Device identity to free
483 * Remove an interrupt handler. The handler is removed and if the
484 * interrupt line is no longer in use by any driver it is disabled.
485 * On a shared IRQ the caller must ensure the interrupt is disabled
486 * on the card it drives before calling this function. The function
487 * does not return until any executing interrupts for this IRQ
490 * This function must not be called from interrupt context.
492 void free_irq(unsigned int irq, void *dev_id)
494 struct irq_desc *desc;
495 struct irqaction **p;
498 WARN_ON(in_interrupt());
502 desc = irq_desc + irq;
503 spin_lock_irqsave(&desc->lock, flags);
506 struct irqaction *action = *p;
509 struct irqaction **pp = p;
512 if (action->dev_id != dev_id)
515 /* Found it - now remove it from the list of entries */
518 /* Currently used only by UML, might disappear one day.*/
519 #ifdef CONFIG_IRQ_RELEASE_METHOD
520 if (desc->chip->release)
521 desc->chip->release(irq, dev_id);
525 desc->status |= IRQ_DISABLED;
526 if (desc->chip->shutdown)
527 desc->chip->shutdown(irq);
529 desc->chip->disable(irq);
531 spin_unlock_irqrestore(&desc->lock, flags);
532 unregister_handler_proc(irq, action);
534 /* Make sure it's not being used on another CPU */
535 synchronize_irq(irq);
536 #ifdef CONFIG_DEBUG_SHIRQ
538 * It's a shared IRQ -- the driver ought to be
539 * prepared for it to happen even now it's
540 * being freed, so let's make sure.... We do
541 * this after actually deregistering it, to
542 * make sure that a 'real' IRQ doesn't run in
543 * parallel with our fake
545 if (action->flags & IRQF_SHARED) {
546 local_irq_save(flags);
547 action->handler(irq, dev_id);
548 local_irq_restore(flags);
554 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
555 #ifdef CONFIG_DEBUG_SHIRQ
558 spin_unlock_irqrestore(&desc->lock, flags);
562 EXPORT_SYMBOL(free_irq);
565 * request_irq - allocate an interrupt line
566 * @irq: Interrupt line to allocate
567 * @handler: Function to be called when the IRQ occurs
568 * @irqflags: Interrupt type flags
569 * @devname: An ascii name for the claiming device
570 * @dev_id: A cookie passed back to the handler function
572 * This call allocates interrupt resources and enables the
573 * interrupt line and IRQ handling. From the point this
574 * call is made your handler function may be invoked. Since
575 * your handler function must clear any interrupt the board
576 * raises, you must take care both to initialise your hardware
577 * and to set up the interrupt handler in the right order.
579 * Dev_id must be globally unique. Normally the address of the
580 * device data structure is used as the cookie. Since the handler
581 * receives this value it makes sense to use it.
583 * If your interrupt is shared you must pass a non NULL dev_id
584 * as this is required when freeing the interrupt.
588 * IRQF_SHARED Interrupt is shared
589 * IRQF_DISABLED Disable local interrupts while processing
590 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
593 int request_irq(unsigned int irq, irq_handler_t handler,
594 unsigned long irqflags, const char *devname, void *dev_id)
596 struct irqaction *action;
599 #ifdef CONFIG_LOCKDEP
601 * Lockdep wants atomic interrupt handlers:
603 irqflags |= IRQF_DISABLED;
606 * Sanity-check: shared interrupts must pass in a real dev-ID,
607 * otherwise we'll have trouble later trying to figure out
608 * which interrupt is which (messes up the interrupt freeing
611 if ((irqflags & IRQF_SHARED) && !dev_id)
615 if (irq_desc[irq].status & IRQ_NOREQUEST)
620 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
624 action->handler = handler;
625 action->flags = irqflags;
626 cpus_clear(action->mask);
627 action->name = devname;
629 action->dev_id = dev_id;
631 #ifdef CONFIG_DEBUG_SHIRQ
632 if (irqflags & IRQF_SHARED) {
634 * It's a shared IRQ -- the driver ought to be prepared for it
635 * to happen immediately, so let's make sure....
636 * We do this before actually registering it, to make sure that
637 * a 'real' IRQ doesn't run in parallel with our fake
641 local_irq_save(flags);
642 handler(irq, dev_id);
643 local_irq_restore(flags);
647 retval = setup_irq(irq, action);
653 EXPORT_SYMBOL(request_irq);