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 static 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 static 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 static DEFINE_SPINLOCK(sparse_irq_lock
);
118 struct irq_desc
*irq_desc_ptrs
[NR_IRQS
] __read_mostly
;
120 static struct irq_desc irq_desc_legacy
[16] __cacheline_aligned_in_smp
= {
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
[16][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
);
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
224 * What should we do if we get a hw irq event on an illegal vector?
225 * Each architecture has to answer this themself.
227 static void ack_bad(unsigned int irq
)
229 struct irq_desc
*desc
= irq_to_desc(irq
);
231 print_irq_desc(irq
, desc
);
238 static void noop(unsigned int irq
)
242 static unsigned int noop_ret(unsigned int irq
)
248 * Generic no controller implementation
250 struct irq_chip no_irq_chip
= {
261 * Generic dummy implementation which can be used for
262 * real dumb interrupt sources
264 struct irq_chip dummy_irq_chip
= {
277 * Special, empty irq handler:
279 irqreturn_t
no_action(int cpl
, void *dev_id
)
285 * handle_IRQ_event - irq action chain handler
286 * @irq: the interrupt number
287 * @action: the interrupt action chain for this irq
289 * Handles the action chain of an irq event
291 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
293 irqreturn_t ret
, retval
= IRQ_NONE
;
294 unsigned int status
= 0;
296 if (!(action
->flags
& IRQF_DISABLED
))
297 local_irq_enable_in_hardirq();
300 ret
= action
->handler(irq
, action
->dev_id
);
301 if (ret
== IRQ_HANDLED
)
302 status
|= action
->flags
;
304 action
= action
->next
;
307 if (status
& IRQF_SAMPLE_RANDOM
)
308 add_interrupt_randomness(irq
);
314 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
316 * __do_IRQ - original all in one highlevel IRQ handler
317 * @irq: the interrupt number
319 * __do_IRQ handles all normal device IRQ's (the special
320 * SMP cross-CPU interrupts have their own specific
323 * This is the original x86 implementation which is used for every
326 unsigned int __do_IRQ(unsigned int irq
)
328 struct irq_desc
*desc
= irq_to_desc(irq
);
329 struct irqaction
*action
;
332 kstat_incr_irqs_this_cpu(irq
, desc
);
334 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
335 irqreturn_t action_ret
;
338 * No locking required for CPU-local interrupts:
341 desc
->chip
->ack(irq
);
342 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
343 action_ret
= handle_IRQ_event(irq
, desc
->action
);
345 note_interrupt(irq
, desc
, action_ret
);
347 desc
->chip
->end(irq
);
351 spin_lock(&desc
->lock
);
353 desc
->chip
->ack(irq
);
355 * REPLAY is when Linux resends an IRQ that was dropped earlier
356 * WAITING is used by probe to mark irqs that are being tested
358 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
359 status
|= IRQ_PENDING
; /* we _want_ to handle it */
362 * If the IRQ is disabled for whatever reason, we cannot
363 * use the action we have.
366 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
367 action
= desc
->action
;
368 status
&= ~IRQ_PENDING
; /* we commit to handling */
369 status
|= IRQ_INPROGRESS
; /* we are handling it */
371 desc
->status
= status
;
374 * If there is no IRQ handler or it was disabled, exit early.
375 * Since we set PENDING, if another processor is handling
376 * a different instance of this same irq, the other processor
377 * will take care of it.
379 if (unlikely(!action
))
383 * Edge triggered interrupts need to remember
385 * This applies to any hw interrupts that allow a second
386 * instance of the same irq to arrive while we are in do_IRQ
387 * or in the handler. But the code here only handles the _second_
388 * instance of the irq, not the third or fourth. So it is mostly
389 * useful for irq hardware that does not mask cleanly in an
393 irqreturn_t action_ret
;
395 spin_unlock(&desc
->lock
);
397 action_ret
= handle_IRQ_event(irq
, action
);
399 note_interrupt(irq
, desc
, action_ret
);
401 spin_lock(&desc
->lock
);
402 if (likely(!(desc
->status
& IRQ_PENDING
)))
404 desc
->status
&= ~IRQ_PENDING
;
406 desc
->status
&= ~IRQ_INPROGRESS
;
410 * The ->end() handler has to deal with interrupts which got
411 * disabled while the handler was running.
413 desc
->chip
->end(irq
);
414 spin_unlock(&desc
->lock
);
421 #ifdef CONFIG_TRACE_IRQFLAGS
422 void early_init_irq_lock_class(void)
424 #ifndef CONFIG_SPARSE_IRQ
425 struct irq_desc
*desc
;
428 for_each_irq_desc(i
, desc
) {
432 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
438 #ifdef CONFIG_SPARSE_IRQ
439 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
441 struct irq_desc
*desc
= irq_to_desc(irq
);
442 return desc
->kstat_irqs
[cpu
];
445 EXPORT_SYMBOL(kstat_irqs_cpu
);