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
142 int set_irq_wake(unsigned int irq
, unsigned int on
)
144 struct irq_desc
*desc
= irq_desc
+ irq
;
148 spin_lock_irqsave(&desc
->lock
, flags
);
149 if (desc
->chip
->set_wake
)
150 ret
= desc
->chip
->set_wake(irq
, on
);
151 spin_unlock_irqrestore(&desc
->lock
, flags
);
154 EXPORT_SYMBOL(set_irq_wake
);
157 * Internal function that tells the architecture code whether a
158 * particular irq has been exclusively allocated or is available
161 int can_request_irq(unsigned int irq
, unsigned long irqflags
)
163 struct irqaction
*action
;
165 if (irq
>= NR_IRQS
|| irq_desc
[irq
].status
& IRQ_NOREQUEST
)
168 action
= irq_desc
[irq
].action
;
170 if (irqflags
& action
->flags
& IRQF_SHARED
)
176 void compat_irq_chip_set_default_handler(struct irq_desc
*desc
)
179 * If the architecture still has not overriden
180 * the flow handler then zap the default. This
181 * should catch incorrect flow-type setting.
183 if (desc
->handle_irq
== &handle_bad_irq
)
184 desc
->handle_irq
= NULL
;
188 * Internal function to register an irqaction - typically used to
189 * allocate special interrupts that are part of the architecture.
191 int setup_irq(unsigned int irq
, struct irqaction
*new)
193 struct irq_desc
*desc
= irq_desc
+ irq
;
194 struct irqaction
*old
, **p
;
201 if (desc
->chip
== &no_irq_chip
)
204 * Some drivers like serial.c use request_irq() heavily,
205 * so we have to be careful not to interfere with a
208 if (new->flags
& IRQF_SAMPLE_RANDOM
) {
210 * This function might sleep, we want to call it first,
211 * outside of the atomic block.
212 * Yes, this might clear the entropy pool if the wrong
213 * driver is attempted to be loaded, without actually
214 * installing a new handler, but is this really a problem,
215 * only the sysadmin is able to do this.
217 rand_initialize_irq(irq
);
221 * The following block of code has to be executed atomically
223 spin_lock_irqsave(&desc
->lock
, flags
);
228 * Can't share interrupts unless both agree to and are
229 * the same type (level, edge, polarity). So both flag
230 * fields must have IRQF_SHARED set and the bits which
231 * set the trigger type must match.
233 if (!((old
->flags
& new->flags
) & IRQF_SHARED
) ||
234 ((old
->flags
^ new->flags
) & IRQF_TRIGGER_MASK
))
237 #if defined(CONFIG_IRQ_PER_CPU)
238 /* All handlers must agree on per-cpuness */
239 if ((old
->flags
& IRQF_PERCPU
) !=
240 (new->flags
& IRQF_PERCPU
))
244 /* add new interrupt at end of irq queue */
253 #if defined(CONFIG_IRQ_PER_CPU)
254 if (new->flags
& IRQF_PERCPU
)
255 desc
->status
|= IRQ_PER_CPU
;
258 irq_chip_set_defaults(desc
->chip
);
260 /* Setup the type (level, edge polarity) if configured: */
261 if (new->flags
& IRQF_TRIGGER_MASK
) {
262 if (desc
->chip
&& desc
->chip
->set_type
)
263 desc
->chip
->set_type(irq
,
264 new->flags
& IRQF_TRIGGER_MASK
);
267 * IRQF_TRIGGER_* but the PIC does not support
268 * multiple flow-types?
270 printk(KERN_WARNING
"No IRQF_TRIGGER set_type "
271 "function for IRQ %d (%s)\n", irq
,
272 desc
->chip
? desc
->chip
->name
:
275 compat_irq_chip_set_default_handler(desc
);
277 desc
->status
&= ~(IRQ_AUTODETECT
| IRQ_WAITING
|
280 if (!(desc
->status
& IRQ_NOAUTOEN
)) {
282 desc
->status
&= ~IRQ_DISABLED
;
283 if (desc
->chip
->startup
)
284 desc
->chip
->startup(irq
);
286 desc
->chip
->enable(irq
);
288 /* Undo nested disables: */
291 spin_unlock_irqrestore(&desc
->lock
, flags
);
294 register_irq_proc(irq
);
296 register_handler_proc(irq
, new);
301 spin_unlock_irqrestore(&desc
->lock
, flags
);
302 if (!(new->flags
& IRQF_PROBE_SHARED
)) {
303 printk(KERN_ERR
"IRQ handler type mismatch for IRQ %d\n", irq
);
310 * free_irq - free an interrupt
311 * @irq: Interrupt line to free
312 * @dev_id: Device identity to free
314 * Remove an interrupt handler. The handler is removed and if the
315 * interrupt line is no longer in use by any driver it is disabled.
316 * On a shared IRQ the caller must ensure the interrupt is disabled
317 * on the card it drives before calling this function. The function
318 * does not return until any executing interrupts for this IRQ
321 * This function must not be called from interrupt context.
323 void free_irq(unsigned int irq
, void *dev_id
)
325 struct irq_desc
*desc
;
326 struct irqaction
**p
;
329 WARN_ON(in_interrupt());
333 desc
= irq_desc
+ irq
;
334 spin_lock_irqsave(&desc
->lock
, flags
);
337 struct irqaction
*action
= *p
;
340 struct irqaction
**pp
= p
;
343 if (action
->dev_id
!= dev_id
)
346 /* Found it - now remove it from the list of entries */
349 /* Currently used only by UML, might disappear one day.*/
350 #ifdef CONFIG_IRQ_RELEASE_METHOD
351 if (desc
->chip
->release
)
352 desc
->chip
->release(irq
, dev_id
);
356 desc
->status
|= IRQ_DISABLED
;
357 if (desc
->chip
->shutdown
)
358 desc
->chip
->shutdown(irq
);
360 desc
->chip
->disable(irq
);
362 spin_unlock_irqrestore(&desc
->lock
, flags
);
363 unregister_handler_proc(irq
, action
);
365 /* Make sure it's not being used on another CPU */
366 synchronize_irq(irq
);
370 printk(KERN_ERR
"Trying to free already-free IRQ %d\n", irq
);
371 spin_unlock_irqrestore(&desc
->lock
, flags
);
375 EXPORT_SYMBOL(free_irq
);
378 * request_irq - allocate an interrupt line
379 * @irq: Interrupt line to allocate
380 * @handler: Function to be called when the IRQ occurs
381 * @irqflags: Interrupt type flags
382 * @devname: An ascii name for the claiming device
383 * @dev_id: A cookie passed back to the handler function
385 * This call allocates interrupt resources and enables the
386 * interrupt line and IRQ handling. From the point this
387 * call is made your handler function may be invoked. Since
388 * your handler function must clear any interrupt the board
389 * raises, you must take care both to initialise your hardware
390 * and to set up the interrupt handler in the right order.
392 * Dev_id must be globally unique. Normally the address of the
393 * device data structure is used as the cookie. Since the handler
394 * receives this value it makes sense to use it.
396 * If your interrupt is shared you must pass a non NULL dev_id
397 * as this is required when freeing the interrupt.
401 * IRQF_SHARED Interrupt is shared
402 * IRQF_DISABLED Disable local interrupts while processing
403 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
406 int request_irq(unsigned int irq
,
407 irqreturn_t (*handler
)(int, void *, struct pt_regs
*),
408 unsigned long irqflags
, const char *devname
, void *dev_id
)
410 struct irqaction
*action
;
413 #ifdef CONFIG_LOCKDEP
415 * Lockdep wants atomic interrupt handlers:
417 irqflags
|= SA_INTERRUPT
;
420 * Sanity-check: shared interrupts must pass in a real dev-ID,
421 * otherwise we'll have trouble later trying to figure out
422 * which interrupt is which (messes up the interrupt freeing
425 if ((irqflags
& IRQF_SHARED
) && !dev_id
)
429 if (irq_desc
[irq
].status
& IRQ_NOREQUEST
)
434 action
= kmalloc(sizeof(struct irqaction
), GFP_ATOMIC
);
438 action
->handler
= handler
;
439 action
->flags
= irqflags
;
440 cpus_clear(action
->mask
);
441 action
->name
= devname
;
443 action
->dev_id
= dev_id
;
445 select_smp_affinity(irq
);
447 retval
= setup_irq(irq
, action
);
453 EXPORT_SYMBOL(request_irq
);
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