2 * linux/kernel/irq/handle.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
7 * This file contains the core interrupt handling code.
9 * Detailed information is available in Documentation/DocBook/genericirq
13 #include <linux/irq.h>
14 #include <linux/module.h>
15 #include <linux/random.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/rculist.h>
19 #include <linux/hash.h>
21 #include "internals.h"
24 * lockdep: we want to handle all irq_desc locks as a single lock-class:
26 struct lock_class_key irq_desc_lock_class
;
29 * handle_bad_irq - handle spurious and unhandled irqs
30 * @irq: the interrupt number
31 * @desc: description of the interrupt
33 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
35 void handle_bad_irq(unsigned int irq
, struct irq_desc
*desc
)
37 print_irq_desc(irq
, desc
);
38 kstat_incr_irqs_this_cpu(irq
, desc
);
43 * Linux has a controller-independent interrupt architecture.
44 * Every controller has a 'controller-template', that is used
45 * by the main code to do the right thing. Each driver-visible
46 * interrupt source is transparently wired to the appropriate
47 * controller. Thus drivers need not be aware of the
48 * interrupt-controller.
50 * The code is designed to be easily extended with new/different
51 * interrupt controllers, without having to do assembly magic or
52 * having to touch the generic code.
54 * Controller mappings for all interrupt sources:
56 int nr_irqs
= NR_IRQS
;
57 EXPORT_SYMBOL_GPL(nr_irqs
);
59 #ifdef CONFIG_SPARSE_IRQ
60 static struct irq_desc irq_desc_init
= {
62 .status
= IRQ_DISABLED
,
64 .handle_irq
= handle_bad_irq
,
66 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
68 .affinity
= CPU_MASK_ALL
72 void init_kstat_irqs(struct irq_desc
*desc
, int cpu
, int nr
)
78 /* Compute how many bytes we need per irq and allocate them */
79 bytes
= nr
* sizeof(unsigned int);
81 node
= cpu_to_node(cpu
);
82 ptr
= kzalloc_node(bytes
, GFP_ATOMIC
, node
);
83 printk(KERN_DEBUG
" alloc kstat_irqs on cpu %d node %d\n", cpu
, node
);
86 desc
->kstat_irqs
= (unsigned int *)ptr
;
89 static void init_one_irq_desc(int irq
, struct irq_desc
*desc
, int cpu
)
91 memcpy(desc
, &irq_desc_init
, sizeof(struct irq_desc
));
93 spin_lock_init(&desc
->lock
);
98 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
99 init_kstat_irqs(desc
, cpu
, nr_cpu_ids
);
100 if (!desc
->kstat_irqs
) {
101 printk(KERN_ERR
"can not alloc kstat_irqs\n");
104 arch_init_chip_data(desc
, cpu
);
108 * Protect the sparse_irqs:
110 DEFINE_SPINLOCK(sparse_irq_lock
);
112 struct irq_desc
*irq_desc_ptrs
[NR_IRQS
] __read_mostly
;
114 static struct irq_desc irq_desc_legacy
[NR_IRQS_LEGACY
] __cacheline_aligned_in_smp
= {
115 [0 ... NR_IRQS_LEGACY
-1] = {
117 .status
= IRQ_DISABLED
,
118 .chip
= &no_irq_chip
,
119 .handle_irq
= handle_bad_irq
,
121 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
123 .affinity
= CPU_MASK_ALL
128 /* FIXME: use bootmem alloc ...*/
129 static unsigned int kstat_irqs_legacy
[NR_IRQS_LEGACY
][NR_CPUS
];
131 int __init
early_irq_init(void)
133 struct irq_desc
*desc
;
137 desc
= irq_desc_legacy
;
138 legacy_count
= ARRAY_SIZE(irq_desc_legacy
);
140 for (i
= 0; i
< legacy_count
; i
++) {
142 desc
[i
].kstat_irqs
= kstat_irqs_legacy
[i
];
143 lockdep_set_class(&desc
[i
].lock
, &irq_desc_lock_class
);
145 irq_desc_ptrs
[i
] = desc
+ i
;
148 for (i
= legacy_count
; i
< NR_IRQS
; i
++)
149 irq_desc_ptrs
[i
] = NULL
;
151 return arch_early_irq_init();
154 struct irq_desc
*irq_to_desc(unsigned int irq
)
156 return (irq
< NR_IRQS
) ? irq_desc_ptrs
[irq
] : NULL
;
159 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
161 struct irq_desc
*desc
;
165 if (irq
>= NR_IRQS
) {
166 printk(KERN_WARNING
"irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
172 desc
= irq_desc_ptrs
[irq
];
176 spin_lock_irqsave(&sparse_irq_lock
, flags
);
178 /* We have to check it to avoid races with another CPU */
179 desc
= irq_desc_ptrs
[irq
];
183 node
= cpu_to_node(cpu
);
184 desc
= kzalloc_node(sizeof(*desc
), GFP_ATOMIC
, node
);
185 printk(KERN_DEBUG
" alloc irq_desc for %d on cpu %d node %d\n",
188 printk(KERN_ERR
"can not alloc irq_desc\n");
191 init_one_irq_desc(irq
, desc
, cpu
);
193 irq_desc_ptrs
[irq
] = desc
;
196 spin_unlock_irqrestore(&sparse_irq_lock
, flags
);
201 #else /* !CONFIG_SPARSE_IRQ */
203 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
204 [0 ... NR_IRQS
-1] = {
205 .status
= IRQ_DISABLED
,
206 .chip
= &no_irq_chip
,
207 .handle_irq
= handle_bad_irq
,
209 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc
->lock
),
211 .affinity
= CPU_MASK_ALL
216 int __init
early_irq_init(void)
218 struct irq_desc
*desc
;
223 count
= ARRAY_SIZE(irq_desc
);
225 for (i
= 0; i
< count
; i
++)
228 return arch_early_irq_init();
231 struct irq_desc
*irq_to_desc(unsigned int irq
)
233 return (irq
< NR_IRQS
) ? irq_desc
+ irq
: NULL
;
236 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
238 return irq_to_desc(irq
);
240 #endif /* !CONFIG_SPARSE_IRQ */
243 * What should we do if we get a hw irq event on an illegal vector?
244 * Each architecture has to answer this themself.
246 static void ack_bad(unsigned int irq
)
248 struct irq_desc
*desc
= irq_to_desc(irq
);
250 print_irq_desc(irq
, desc
);
257 static void noop(unsigned int irq
)
261 static unsigned int noop_ret(unsigned int irq
)
267 * Generic no controller implementation
269 struct irq_chip no_irq_chip
= {
280 * Generic dummy implementation which can be used for
281 * real dumb interrupt sources
283 struct irq_chip dummy_irq_chip
= {
296 * Special, empty irq handler:
298 irqreturn_t
no_action(int cpl
, void *dev_id
)
304 * handle_IRQ_event - irq action chain handler
305 * @irq: the interrupt number
306 * @action: the interrupt action chain for this irq
308 * Handles the action chain of an irq event
310 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
312 irqreturn_t ret
, retval
= IRQ_NONE
;
313 unsigned int status
= 0;
315 if (!(action
->flags
& IRQF_DISABLED
))
316 local_irq_enable_in_hardirq();
319 ret
= action
->handler(irq
, action
->dev_id
);
320 if (ret
== IRQ_HANDLED
)
321 status
|= action
->flags
;
323 action
= action
->next
;
326 if (status
& IRQF_SAMPLE_RANDOM
)
327 add_interrupt_randomness(irq
);
333 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
335 * __do_IRQ - original all in one highlevel IRQ handler
336 * @irq: the interrupt number
338 * __do_IRQ handles all normal device IRQ's (the special
339 * SMP cross-CPU interrupts have their own specific
342 * This is the original x86 implementation which is used for every
345 unsigned int __do_IRQ(unsigned int irq
)
347 struct irq_desc
*desc
= irq_to_desc(irq
);
348 struct irqaction
*action
;
351 kstat_incr_irqs_this_cpu(irq
, desc
);
353 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
354 irqreturn_t action_ret
;
357 * No locking required for CPU-local interrupts:
359 if (desc
->chip
->ack
) {
360 desc
->chip
->ack(irq
);
362 desc
= irq_remap_to_desc(irq
, desc
);
364 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
365 action_ret
= handle_IRQ_event(irq
, desc
->action
);
367 note_interrupt(irq
, desc
, action_ret
);
369 desc
->chip
->end(irq
);
373 spin_lock(&desc
->lock
);
374 if (desc
->chip
->ack
) {
375 desc
->chip
->ack(irq
);
376 desc
= irq_remap_to_desc(irq
, desc
);
379 * REPLAY is when Linux resends an IRQ that was dropped earlier
380 * WAITING is used by probe to mark irqs that are being tested
382 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
383 status
|= IRQ_PENDING
; /* we _want_ to handle it */
386 * If the IRQ is disabled for whatever reason, we cannot
387 * use the action we have.
390 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
391 action
= desc
->action
;
392 status
&= ~IRQ_PENDING
; /* we commit to handling */
393 status
|= IRQ_INPROGRESS
; /* we are handling it */
395 desc
->status
= status
;
398 * If there is no IRQ handler or it was disabled, exit early.
399 * Since we set PENDING, if another processor is handling
400 * a different instance of this same irq, the other processor
401 * will take care of it.
403 if (unlikely(!action
))
407 * Edge triggered interrupts need to remember
409 * This applies to any hw interrupts that allow a second
410 * instance of the same irq to arrive while we are in do_IRQ
411 * or in the handler. But the code here only handles the _second_
412 * instance of the irq, not the third or fourth. So it is mostly
413 * useful for irq hardware that does not mask cleanly in an
417 irqreturn_t action_ret
;
419 spin_unlock(&desc
->lock
);
421 action_ret
= handle_IRQ_event(irq
, action
);
423 note_interrupt(irq
, desc
, action_ret
);
425 spin_lock(&desc
->lock
);
426 if (likely(!(desc
->status
& IRQ_PENDING
)))
428 desc
->status
&= ~IRQ_PENDING
;
430 desc
->status
&= ~IRQ_INPROGRESS
;
434 * The ->end() handler has to deal with interrupts which got
435 * disabled while the handler was running.
437 desc
->chip
->end(irq
);
438 spin_unlock(&desc
->lock
);
444 void early_init_irq_lock_class(void)
446 struct irq_desc
*desc
;
449 for_each_irq_desc(i
, desc
) {
450 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
454 #ifdef CONFIG_SPARSE_IRQ
455 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
457 struct irq_desc
*desc
= irq_to_desc(irq
);
458 return desc
? desc
->kstat_irqs
[cpu
] : 0;
461 EXPORT_SYMBOL(kstat_irqs_cpu
);