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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - kernel/irq/manage.c
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"
21 * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
22 * @irq: interrupt number to wait for
24 * This function waits for any pending IRQ handlers for this interrupt
25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
28 * This function may be called - with care - from IRQ context.
30 void synchronize_irq(unsigned int irq
)
32 struct irq_desc
*desc
= irq_desc
+ irq
;
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
45 while (desc
->status
& IRQ_INPROGRESS
)
48 /* Ok, that indicated we're done: double-check carefully. */
49 spin_lock_irqsave(&desc
->lock
, flags
);
50 status
= desc
->status
;
51 spin_unlock_irqrestore(&desc
->lock
, flags
);
53 /* Oops, that failed? */
54 } while (status
& IRQ_INPROGRESS
);
56 EXPORT_SYMBOL(synchronize_irq
);
59 * irq_can_set_affinity - Check if the affinity of a given irq can be set
60 * @irq: Interrupt to check
63 int irq_can_set_affinity(unsigned int irq
)
65 struct irq_desc
*desc
= irq_desc
+ irq
;
67 if (CHECK_IRQ_PER_CPU(desc
->status
) || !desc
->chip
||
68 !desc
->chip
->set_affinity
)
75 * irq_set_affinity - Set the irq affinity of a given irq
76 * @irq: Interrupt to set affinity
80 int irq_set_affinity(unsigned int irq
, cpumask_t cpumask
)
82 struct irq_desc
*desc
= irq_desc
+ irq
;
84 if (!desc
->chip
->set_affinity
)
87 set_balance_irq_affinity(irq
, cpumask
);
89 #ifdef CONFIG_GENERIC_PENDING_IRQ
90 set_pending_irq(irq
, cpumask
);
92 desc
->affinity
= cpumask
;
93 desc
->chip
->set_affinity(irq
, cpumask
);
101 * disable_irq_nosync - disable an irq without waiting
102 * @irq: Interrupt to disable
104 * Disable the selected interrupt line. Disables and Enables are
106 * Unlike disable_irq(), this function does not ensure existing
107 * instances of the IRQ handler have completed before returning.
109 * This function may be called from IRQ context.
111 void disable_irq_nosync(unsigned int irq
)
113 struct irq_desc
*desc
= irq_desc
+ irq
;
119 spin_lock_irqsave(&desc
->lock
, flags
);
120 if (!desc
->depth
++) {
121 desc
->status
|= IRQ_DISABLED
;
122 desc
->chip
->disable(irq
);
124 spin_unlock_irqrestore(&desc
->lock
, flags
);
126 EXPORT_SYMBOL(disable_irq_nosync
);
129 * disable_irq - disable an irq and wait for completion
130 * @irq: Interrupt to disable
132 * Disable the selected interrupt line. Enables and Disables are
134 * This function waits for any pending IRQ handlers for this interrupt
135 * to complete before returning. If you use this function while
136 * holding a resource the IRQ handler may need you will deadlock.
138 * This function may be called - with care - from IRQ context.
140 void disable_irq(unsigned int irq
)
142 struct irq_desc
*desc
= irq_desc
+ irq
;
147 disable_irq_nosync(irq
);
149 synchronize_irq(irq
);
151 EXPORT_SYMBOL(disable_irq
);
154 * enable_irq - enable handling of an irq
155 * @irq: Interrupt to enable
157 * Undoes the effect of one call to disable_irq(). If this
158 * matches the last disable, processing of interrupts on this
159 * IRQ line is re-enabled.
161 * This function may be called from IRQ context.
163 void enable_irq(unsigned int irq
)
165 struct irq_desc
*desc
= irq_desc
+ irq
;
171 spin_lock_irqsave(&desc
->lock
, flags
);
172 switch (desc
->depth
) {
174 printk(KERN_WARNING
"Unbalanced enable for IRQ %d\n", irq
);
178 unsigned int status
= desc
->status
& ~IRQ_DISABLED
;
180 /* Prevent probing on this irq: */
181 desc
->status
= status
| IRQ_NOPROBE
;
182 check_irq_resend(desc
, irq
);
188 spin_unlock_irqrestore(&desc
->lock
, flags
);
190 EXPORT_SYMBOL(enable_irq
);
193 * set_irq_wake - control irq power management wakeup
194 * @irq: interrupt to control
195 * @on: enable/disable power management wakeup
197 * Enable/disable power management wakeup mode, which is
198 * disabled by default. Enables and disables must match,
199 * just as they match for non-wakeup mode support.
201 * Wakeup mode lets this IRQ wake the system from sleep
202 * states like "suspend to RAM".
204 int set_irq_wake(unsigned int irq
, unsigned int on
)
206 struct irq_desc
*desc
= irq_desc
+ irq
;
209 int (*set_wake
)(unsigned, unsigned) = desc
->chip
->set_wake
;
211 /* wakeup-capable irqs can be shared between drivers that
212 * don't need to have the same sleep mode behaviors.
214 spin_lock_irqsave(&desc
->lock
, flags
);
216 if (desc
->wake_depth
++ == 0)
217 desc
->status
|= IRQ_WAKEUP
;
221 if (desc
->wake_depth
== 0) {
222 printk(KERN_WARNING
"Unbalanced IRQ %d "
223 "wake disable\n", irq
);
225 } else if (--desc
->wake_depth
== 0)
226 desc
->status
&= ~IRQ_WAKEUP
;
231 ret
= desc
->chip
->set_wake(irq
, on
);
232 spin_unlock_irqrestore(&desc
->lock
, flags
);
235 EXPORT_SYMBOL(set_irq_wake
);
238 * Internal function that tells the architecture code whether a
239 * particular irq has been exclusively allocated or is available
242 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
244 struct irqaction
*action
;
246 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
249 action
= irq_desc
[irq
].action
;
251 if (irqflags
& action
->flags
& IRQF_SHARED
)
257 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
260 * If the architecture still has not overriden
261 * the flow handler then zap the default. This
262 * should catch incorrect flow-type setting.
264 if (desc
->handle_irq
== &handle_bad_irq
)
265 desc
->handle_irq
= NULL
;
269 * Internal function to register an irqaction - typically used to
270 * allocate special interrupts that are part of the architecture.
272 int setup_irq(unsigned int irq
, struct irqaction
*new)
274 struct irq_desc
*desc
= irq_desc
+ irq
;
275 struct irqaction
*old
, **p
;
276 const char *old_name
= NULL
;
283 if (desc
->chip
== &no_irq_chip
)
286 * Some drivers like serial.c use request_irq() heavily,
287 * so we have to be careful not to interfere with a
290 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
292 * This function might sleep, we want to call it first,
293 * outside of the atomic block.
294 * Yes, this might clear the entropy pool if the wrong
295 * driver is attempted to be loaded, without actually
296 * installing a new handler, but is this really a problem,
297 * only the sysadmin is able to do this.
299 rand_initialize_irq(irq
);
303 * The following block of code has to be executed atomically
305 spin_lock_irqsave(&desc
->lock
, flags
);
310 * Can't share interrupts unless both agree to and are
311 * the same type (level, edge, polarity). So both flag
312 * fields must have IRQF_SHARED set and the bits which
313 * set the trigger type must match.
315 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
316 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
)) {
317 old_name
= old
->name
;
321 #if defined(CONFIG_IRQ_PER_CPU)
322 /* All handlers must agree on per-cpuness */
323 if ((old
->flags
& IRQF_PERCPU
) !=
324 (new->flags
& IRQF_PERCPU
))
328 /* add new interrupt at end of irq queue */
338 /* Exclude IRQ from balancing */
339 if (new->flags
& IRQF_NOBALANCING
)
340 desc
->status
|= IRQ_NO_BALANCING
;
343 irq_chip_set_defaults(desc
->chip
);
345 #if defined(CONFIG_IRQ_PER_CPU)
346 if (new->flags
& IRQF_PERCPU
)
347 desc
->status
|= IRQ_PER_CPU
;
350 /* Setup the type (level, edge polarity) if configured: */
351 if (new->flags
& IRQF_TRIGGER_MASK
) {
352 if (desc
->chip
&& desc
->chip
->set_type
)
353 desc
->chip
->set_type(irq
,
354 new->flags
& IRQF_TRIGGER_MASK
);
357 * IRQF_TRIGGER_* but the PIC does not support
358 * multiple flow-types?
360 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
361 "function for IRQ %d (%s)\n", irq
,
362 desc
->chip
? desc
->chip
->name
:
365 compat_irq_chip_set_default_handler(desc
);
367 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
370 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
372 desc
->status
&= ~IRQ_DISABLED
;
373 if (desc
->chip
->startup
)
374 desc
->chip
->startup(irq
);
376 desc
->chip
->enable(irq
);
378 /* Undo nested disables: */
381 /* Reset broken irq detection when installing new handler */
383 desc
->irqs_unhandled
= 0;
384 spin_unlock_irqrestore(&desc
->lock
, flags
);
387 register_irq_proc(irq
);
389 register_handler_proc(irq
, new);
394 #ifdef CONFIG_DEBUG_SHIRQ
395 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
396 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
398 printk(KERN_ERR
"current handler: %s\n", old_name
);
402 spin_unlock_irqrestore(&desc
->lock
, flags
);
407 * free_irq - free an interrupt
408 * @irq: Interrupt line to free
409 * @dev_id: Device identity to free
411 * Remove an interrupt handler. The handler is removed and if the
412 * interrupt line is no longer in use by any driver it is disabled.
413 * On a shared IRQ the caller must ensure the interrupt is disabled
414 * on the card it drives before calling this function. The function
415 * does not return until any executing interrupts for this IRQ
418 * This function must not be called from interrupt context.
420 void free_irq(unsigned int irq
, void *dev_id
)
422 struct irq_desc
*desc
;
423 struct irqaction
**p
;
426 WARN_ON(in_interrupt());
430 desc
= irq_desc
+ irq
;
431 spin_lock_irqsave(&desc
->lock
, flags
);
434 struct irqaction
*action
= *p
;
437 struct irqaction
**pp
= p
;
440 if (action
->dev_id
!= dev_id
)
443 /* Found it - now remove it from the list of entries */
446 /* Currently used only by UML, might disappear one day.*/
447 #ifdef CONFIG_IRQ_RELEASE_METHOD
448 if (desc
->chip
->release
)
449 desc
->chip
->release(irq
, dev_id
);
453 desc
->status
|= IRQ_DISABLED
;
454 if (desc
->chip
->shutdown
)
455 desc
->chip
->shutdown(irq
);
457 desc
->chip
->disable(irq
);
459 spin_unlock_irqrestore(&desc
->lock
, flags
);
460 unregister_handler_proc(irq
, action
);
462 /* Make sure it's not being used on another CPU */
463 synchronize_irq(irq
);
464 #ifdef CONFIG_DEBUG_SHIRQ
466 * It's a shared IRQ -- the driver ought to be
467 * prepared for it to happen even now it's
468 * being freed, so let's make sure.... We do
469 * this after actually deregistering it, to
470 * make sure that a 'real' IRQ doesn't run in
471 * parallel with our fake
473 if (action
->flags
& IRQF_SHARED
) {
474 local_irq_save(flags
);
475 action
->handler(irq
, dev_id
);
476 local_irq_restore(flags
);
482 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
483 #ifdef CONFIG_DEBUG_SHIRQ
486 spin_unlock_irqrestore(&desc
->lock
, flags
);
490 EXPORT_SYMBOL(free_irq
);
493 * request_irq - allocate an interrupt line
494 * @irq: Interrupt line to allocate
495 * @handler: Function to be called when the IRQ occurs
496 * @irqflags: Interrupt type flags
497 * @devname: An ascii name for the claiming device
498 * @dev_id: A cookie passed back to the handler function
500 * This call allocates interrupt resources and enables the
501 * interrupt line and IRQ handling. From the point this
502 * call is made your handler function may be invoked. Since
503 * your handler function must clear any interrupt the board
504 * raises, you must take care both to initialise your hardware
505 * and to set up the interrupt handler in the right order.
507 * Dev_id must be globally unique. Normally the address of the
508 * device data structure is used as the cookie. Since the handler
509 * receives this value it makes sense to use it.
511 * If your interrupt is shared you must pass a non NULL dev_id
512 * as this is required when freeing the interrupt.
516 * IRQF_SHARED Interrupt is shared
517 * IRQF_DISABLED Disable local interrupts while processing
518 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
521 int request_irq(unsigned int irq
, irq_handler_t handler
,
522 unsigned long irqflags
, const char *devname
, void *dev_id
)
524 struct irqaction
*action
;
527 #ifdef CONFIG_LOCKDEP
529 * Lockdep wants atomic interrupt handlers:
531 irqflags
|= IRQF_DISABLED
;
534 * Sanity-check: shared interrupts must pass in a real dev-ID,
535 * otherwise we'll have trouble later trying to figure out
536 * which interrupt is which (messes up the interrupt freeing
539 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
543 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
548 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
552 action
->handler
= handler
;
553 action
->flags
= irqflags
;
554 cpus_clear(action
->mask
);
555 action
->name
= devname
;
557 action
->dev_id
= dev_id
;
559 select_smp_affinity(irq
);
561 #ifdef CONFIG_DEBUG_SHIRQ
562 if (irqflags
& IRQF_SHARED
) {
564 * It's a shared IRQ -- the driver ought to be prepared for it
565 * to happen immediately, so let's make sure....
566 * We do this before actually registering it, to make sure that
567 * a 'real' IRQ doesn't run in parallel with our fake
571 local_irq_save(flags
);
572 handler(irq
, dev_id
);
573 local_irq_restore(flags
);
577 retval
= setup_irq(irq
, action
);
583 EXPORT_SYMBOL(request_irq
);