fs: use kmem_cache_zalloc instead
[pv_ops_mirror.git] / kernel / irq / manage.c
blob7230d914eaa28b86eaba939b5644c899d9872ce3
1 /*
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.
8 */
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/random.h>
13 #include <linux/interrupt.h>
15 #include "internals.h"
17 #ifdef CONFIG_SMP
19 /**
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;
33 if (irq >= NR_IRQS)
34 return;
36 while (desc->status & IRQ_INPROGRESS)
37 cpu_relax();
39 EXPORT_SYMBOL(synchronize_irq);
41 /**
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)
52 return 0;
54 return 1;
57 /**
58 * irq_set_affinity - Set the irq affinity of a given irq
59 * @irq: Interrupt to set affinity
60 * @cpumask: cpumask
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)
68 return -EINVAL;
70 set_balance_irq_affinity(irq, cpumask);
72 #ifdef CONFIG_GENERIC_PENDING_IRQ
73 set_pending_irq(irq, cpumask);
74 #else
75 desc->affinity = cpumask;
76 desc->chip->set_affinity(irq, cpumask);
77 #endif
78 return 0;
81 #endif
83 /**
84 * disable_irq_nosync - disable an irq without waiting
85 * @irq: Interrupt to disable
87 * Disable the selected interrupt line. Disables and Enables are
88 * nested.
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;
97 unsigned long flags;
99 if (irq >= NR_IRQS)
100 return;
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
116 * nested.
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;
127 if (irq >= NR_IRQS)
128 return;
130 disable_irq_nosync(irq);
131 if (desc->action)
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;
149 unsigned long flags;
151 if (irq >= NR_IRQS)
152 return;
154 spin_lock_irqsave(&desc->lock, flags);
155 switch (desc->depth) {
156 case 0:
157 printk(KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
158 WARN_ON(1);
159 break;
160 case 1: {
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);
166 /* fall-through */
168 default:
169 desc->depth--;
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;
190 unsigned long flags;
191 int ret = -ENXIO;
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);
198 if (on) {
199 if (desc->wake_depth++ == 0)
200 desc->status |= IRQ_WAKEUP;
201 else
202 set_wake = NULL;
203 } else {
204 if (desc->wake_depth == 0) {
205 printk(KERN_WARNING "Unbalanced IRQ %d "
206 "wake disable\n", irq);
207 WARN_ON(1);
208 } else if (--desc->wake_depth == 0)
209 desc->status &= ~IRQ_WAKEUP;
210 else
211 set_wake = NULL;
213 if (set_wake)
214 ret = desc->chip->set_wake(irq, on);
215 spin_unlock_irqrestore(&desc->lock, flags);
216 return ret;
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
223 * for driver use.
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)
230 return 0;
232 action = irq_desc[irq].action;
233 if (action)
234 if (irqflags & action->flags & IRQF_SHARED)
235 action = NULL;
237 return !action;
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;
260 unsigned long flags;
261 int shared = 0;
263 if (irq >= NR_IRQS)
264 return -EINVAL;
266 if (desc->chip == &no_irq_chip)
267 return -ENOSYS;
269 * Some drivers like serial.c use request_irq() heavily,
270 * so we have to be careful not to interfere with a
271 * running system.
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);
289 p = &desc->action;
290 old = *p;
291 if (old) {
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;
301 goto mismatch;
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))
308 goto mismatch;
309 #endif
311 /* add new interrupt at end of irq queue */
312 do {
313 p = &old->next;
314 old = *p;
315 } while (old);
316 shared = 1;
319 *p = new;
321 /* Exclude IRQ from balancing */
322 if (new->flags & IRQF_NOBALANCING)
323 desc->status |= IRQ_NO_BALANCING;
325 if (!shared) {
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;
331 #endif
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);
338 else
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 :
346 "unknown");
347 } else
348 compat_irq_chip_set_default_handler(desc);
350 desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
351 IRQ_INPROGRESS);
353 if (!(desc->status & IRQ_NOAUTOEN)) {
354 desc->depth = 0;
355 desc->status &= ~IRQ_DISABLED;
356 if (desc->chip->startup)
357 desc->chip->startup(irq);
358 else
359 desc->chip->enable(irq);
360 } else
361 /* Undo nested disables: */
362 desc->depth = 1;
364 /* Reset broken irq detection when installing new handler */
365 desc->irq_count = 0;
366 desc->irqs_unhandled = 0;
367 spin_unlock_irqrestore(&desc->lock, flags);
369 new->irq = irq;
370 register_irq_proc(irq);
371 new->dir = NULL;
372 register_handler_proc(irq, new);
374 return 0;
376 mismatch:
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);
380 if (old_name)
381 printk(KERN_ERR "current handler: %s\n", old_name);
382 dump_stack();
384 #endif
385 spin_unlock_irqrestore(&desc->lock, flags);
386 return -EBUSY;
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
399 * have completed.
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;
407 unsigned long flags;
408 irqreturn_t (*handler)(int, void *) = NULL;
410 WARN_ON(in_interrupt());
411 if (irq >= NR_IRQS)
412 return;
414 desc = irq_desc + irq;
415 spin_lock_irqsave(&desc->lock, flags);
416 p = &desc->action;
417 for (;;) {
418 struct irqaction *action = *p;
420 if (action) {
421 struct irqaction **pp = p;
423 p = &action->next;
424 if (action->dev_id != dev_id)
425 continue;
427 /* Found it - now remove it from the list of entries */
428 *pp = action->next;
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);
434 #endif
436 if (!desc->action) {
437 desc->status |= IRQ_DISABLED;
438 if (desc->chip->shutdown)
439 desc->chip->shutdown(irq);
440 else
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;
450 kfree(action);
451 return;
453 printk(KERN_ERR "Trying to free already-free IRQ %d\n", irq);
454 spin_unlock_irqrestore(&desc->lock, flags);
455 return;
457 #ifdef CONFIG_DEBUG_SHIRQ
458 if (handler) {
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);
469 #endif
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.
495 * Flags:
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;
506 int retval;
508 #ifdef CONFIG_LOCKDEP
510 * Lockdep wants atomic interrupt handlers:
512 irqflags |= IRQF_DISABLED;
513 #endif
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
518 * logic etc).
520 if ((irqflags & IRQF_SHARED) && !dev_id)
521 return -EINVAL;
522 if (irq >= NR_IRQS)
523 return -EINVAL;
524 if (irq_desc[irq].status & IRQ_NOREQUEST)
525 return -EINVAL;
526 if (!handler)
527 return -EINVAL;
529 action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC);
530 if (!action)
531 return -ENOMEM;
533 action->handler = handler;
534 action->flags = irqflags;
535 cpus_clear(action->mask);
536 action->name = devname;
537 action->next = NULL;
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
550 unsigned long flags;
552 local_irq_save(flags);
553 handler(irq, dev_id);
554 local_irq_restore(flags);
556 #endif
558 retval = setup_irq(irq, action);
559 if (retval)
560 kfree(action);
562 return retval;
564 EXPORT_SYMBOL(request_irq);