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 void __init
__attribute__((weak
)) arch_early_irq_init(void)
63 #ifdef CONFIG_SPARSE_IRQ
64 static struct irq_desc irq_desc_init
= {
66 .status
= IRQ_DISABLED
,
68 .handle_irq
= handle_bad_irq
,
70 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
72 .affinity
= CPU_MASK_ALL
76 void init_kstat_irqs(struct irq_desc
*desc
, int cpu
, int nr
)
82 /* Compute how many bytes we need per irq and allocate them */
83 bytes
= nr
* sizeof(unsigned int);
85 node
= cpu_to_node(cpu
);
86 ptr
= kzalloc_node(bytes
, GFP_ATOMIC
, node
);
87 printk(KERN_DEBUG
" alloc kstat_irqs on cpu %d node %d\n", cpu
, node
);
90 desc
->kstat_irqs
= (unsigned int *)ptr
;
93 void __attribute__((weak
)) arch_init_chip_data(struct irq_desc
*desc
, int cpu
)
97 static void init_one_irq_desc(int irq
, struct irq_desc
*desc
, int cpu
)
99 memcpy(desc
, &irq_desc_init
, sizeof(struct irq_desc
));
104 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
105 init_kstat_irqs(desc
, cpu
, nr_cpu_ids
);
106 if (!desc
->kstat_irqs
) {
107 printk(KERN_ERR
"can not alloc kstat_irqs\n");
110 arch_init_chip_data(desc
, cpu
);
114 * Protect the sparse_irqs:
116 DEFINE_SPINLOCK(sparse_irq_lock
);
118 struct irq_desc
*irq_desc_ptrs
[NR_IRQS
] __read_mostly
;
120 static struct irq_desc irq_desc_legacy
[NR_IRQS_LEGACY
] __cacheline_aligned_in_smp
= {
121 [0 ... NR_IRQS_LEGACY
-1] = {
123 .status
= IRQ_DISABLED
,
124 .chip
= &no_irq_chip
,
125 .handle_irq
= handle_bad_irq
,
127 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
129 .affinity
= CPU_MASK_ALL
134 /* FIXME: use bootmem alloc ...*/
135 static unsigned int kstat_irqs_legacy
[NR_IRQS_LEGACY
][NR_CPUS
];
137 void __init
early_irq_init(void)
139 struct irq_desc
*desc
;
143 desc
= irq_desc_legacy
;
144 legacy_count
= ARRAY_SIZE(irq_desc_legacy
);
146 for (i
= 0; i
< legacy_count
; i
++) {
148 desc
[i
].kstat_irqs
= kstat_irqs_legacy
[i
];
150 irq_desc_ptrs
[i
] = desc
+ i
;
153 for (i
= legacy_count
; i
< NR_IRQS
; i
++)
154 irq_desc_ptrs
[i
] = NULL
;
156 arch_early_irq_init();
159 struct irq_desc
*irq_to_desc(unsigned int irq
)
161 return (irq
< NR_IRQS
) ? irq_desc_ptrs
[irq
] : NULL
;
164 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
166 struct irq_desc
*desc
;
170 if (irq
>= NR_IRQS
) {
171 printk(KERN_WARNING
"irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
177 desc
= irq_desc_ptrs
[irq
];
181 spin_lock_irqsave(&sparse_irq_lock
, flags
);
183 /* We have to check it to avoid races with another CPU */
184 desc
= irq_desc_ptrs
[irq
];
188 node
= cpu_to_node(cpu
);
189 desc
= kzalloc_node(sizeof(*desc
), GFP_ATOMIC
, node
);
190 printk(KERN_DEBUG
" alloc irq_desc for %d on cpu %d node %d\n",
193 printk(KERN_ERR
"can not alloc irq_desc\n");
196 init_one_irq_desc(irq
, desc
, cpu
);
198 irq_desc_ptrs
[irq
] = desc
;
201 spin_unlock_irqrestore(&sparse_irq_lock
, flags
);
206 #else /* !CONFIG_SPARSE_IRQ */
208 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
209 [0 ... NR_IRQS
-1] = {
210 .status
= IRQ_DISABLED
,
211 .chip
= &no_irq_chip
,
212 .handle_irq
= handle_bad_irq
,
214 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc
->lock
),
216 .affinity
= CPU_MASK_ALL
221 struct irq_desc
*irq_to_desc(unsigned int irq
)
223 return (irq
< NR_IRQS
) ? irq_desc
+ irq
: NULL
;
226 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
228 return irq_to_desc(irq
);
230 #endif /* !CONFIG_SPARSE_IRQ */
233 * What should we do if we get a hw irq event on an illegal vector?
234 * Each architecture has to answer this themself.
236 static void ack_bad(unsigned int irq
)
238 struct irq_desc
*desc
= irq_to_desc(irq
);
240 print_irq_desc(irq
, desc
);
247 static void noop(unsigned int irq
)
251 static unsigned int noop_ret(unsigned int irq
)
257 * Generic no controller implementation
259 struct irq_chip no_irq_chip
= {
270 * Generic dummy implementation which can be used for
271 * real dumb interrupt sources
273 struct irq_chip dummy_irq_chip
= {
286 * Special, empty irq handler:
288 irqreturn_t
no_action(int cpl
, void *dev_id
)
294 * handle_IRQ_event - irq action chain handler
295 * @irq: the interrupt number
296 * @action: the interrupt action chain for this irq
298 * Handles the action chain of an irq event
300 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
302 irqreturn_t ret
, retval
= IRQ_NONE
;
303 unsigned int status
= 0;
305 if (!(action
->flags
& IRQF_DISABLED
))
306 local_irq_enable_in_hardirq();
309 ret
= action
->handler(irq
, action
->dev_id
);
310 if (ret
== IRQ_HANDLED
)
311 status
|= action
->flags
;
313 action
= action
->next
;
316 if (status
& IRQF_SAMPLE_RANDOM
)
317 add_interrupt_randomness(irq
);
323 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
325 * __do_IRQ - original all in one highlevel IRQ handler
326 * @irq: the interrupt number
328 * __do_IRQ handles all normal device IRQ's (the special
329 * SMP cross-CPU interrupts have their own specific
332 * This is the original x86 implementation which is used for every
335 unsigned int __do_IRQ(unsigned int irq
)
337 struct irq_desc
*desc
= irq_to_desc(irq
);
338 struct irqaction
*action
;
341 kstat_incr_irqs_this_cpu(irq
, desc
);
343 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
344 irqreturn_t action_ret
;
347 * No locking required for CPU-local interrupts:
349 if (desc
->chip
->ack
) {
350 desc
->chip
->ack(irq
);
352 desc
= irq_remap_to_desc(irq
, desc
);
354 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
355 action_ret
= handle_IRQ_event(irq
, desc
->action
);
357 note_interrupt(irq
, desc
, action_ret
);
359 desc
->chip
->end(irq
);
363 spin_lock(&desc
->lock
);
364 if (desc
->chip
->ack
) {
365 desc
->chip
->ack(irq
);
366 desc
= irq_remap_to_desc(irq
, desc
);
369 * REPLAY is when Linux resends an IRQ that was dropped earlier
370 * WAITING is used by probe to mark irqs that are being tested
372 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
373 status
|= IRQ_PENDING
; /* we _want_ to handle it */
376 * If the IRQ is disabled for whatever reason, we cannot
377 * use the action we have.
380 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
381 action
= desc
->action
;
382 status
&= ~IRQ_PENDING
; /* we commit to handling */
383 status
|= IRQ_INPROGRESS
; /* we are handling it */
385 desc
->status
= status
;
388 * If there is no IRQ handler or it was disabled, exit early.
389 * Since we set PENDING, if another processor is handling
390 * a different instance of this same irq, the other processor
391 * will take care of it.
393 if (unlikely(!action
))
397 * Edge triggered interrupts need to remember
399 * This applies to any hw interrupts that allow a second
400 * instance of the same irq to arrive while we are in do_IRQ
401 * or in the handler. But the code here only handles the _second_
402 * instance of the irq, not the third or fourth. So it is mostly
403 * useful for irq hardware that does not mask cleanly in an
407 irqreturn_t action_ret
;
409 spin_unlock(&desc
->lock
);
411 action_ret
= handle_IRQ_event(irq
, action
);
413 note_interrupt(irq
, desc
, action_ret
);
415 spin_lock(&desc
->lock
);
416 if (likely(!(desc
->status
& IRQ_PENDING
)))
418 desc
->status
&= ~IRQ_PENDING
;
420 desc
->status
&= ~IRQ_INPROGRESS
;
424 * The ->end() handler has to deal with interrupts which got
425 * disabled while the handler was running.
427 desc
->chip
->end(irq
);
428 spin_unlock(&desc
->lock
);
434 void early_init_irq_lock_class(void)
436 struct irq_desc
*desc
;
439 for_each_irq_desc(i
, desc
) {
440 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
444 #ifdef CONFIG_SPARSE_IRQ
445 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
447 struct irq_desc
*desc
= irq_to_desc(irq
);
448 return desc
? desc
->kstat_irqs
[cpu
] : 0;
451 EXPORT_SYMBOL(kstat_irqs_cpu
);