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>
19 #include "internals.h"
21 #ifdef CONFIG_TRACE_IRQFLAGS
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
;
30 * handle_bad_irq - handle spurious and unhandled irqs
31 * @irq: the interrupt number
32 * @desc: description of the interrupt
34 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
37 handle_bad_irq(unsigned int irq
, struct irq_desc
*desc
)
39 print_irq_desc(irq
, desc
);
40 kstat_irqs_this_cpu(desc
)++;
45 * Linux has a controller-independent interrupt architecture.
46 * Every controller has a 'controller-template', that is used
47 * by the main code to do the right thing. Each driver-visible
48 * interrupt source is transparently wired to the appropriate
49 * controller. Thus drivers need not be aware of the
50 * interrupt-controller.
52 * The code is designed to be easily extended with new/different
53 * interrupt controllers, without having to do assembly magic or
54 * having to touch the generic code.
56 * Controller mappings for all interrupt sources:
58 int nr_irqs
= NR_IRQS
;
59 EXPORT_SYMBOL_GPL(nr_irqs
);
61 #ifdef CONFIG_HAVE_DYN_ARRAY
62 static struct irq_desc irq_desc_init
= {
64 .status
= IRQ_DISABLED
,
66 .handle_irq
= handle_bad_irq
,
68 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
70 .affinity
= CPU_MASK_ALL
75 static void init_one_irq_desc(struct irq_desc
*desc
)
77 memcpy(desc
, &irq_desc_init
, sizeof(struct irq_desc
));
78 #ifdef CONFIG_TRACE_IRQFLAGS
79 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
83 extern int after_bootmem
;
84 extern void *__alloc_bootmem_nopanic(unsigned long size
,
88 static void init_kstat_irqs(struct irq_desc
*desc
, int nr_desc
, int nr
)
90 unsigned long bytes
, total_bytes
;
95 /* Compute how many bytes we need per irq and allocate them */
96 bytes
= nr
* sizeof(unsigned int);
97 total_bytes
= bytes
* nr_desc
;
99 ptr
= kzalloc(total_bytes
, GFP_ATOMIC
);
101 ptr
= __alloc_bootmem_nopanic(total_bytes
, PAGE_SIZE
, 0);
104 panic(" can not allocate kstat_irqs\n");
107 printk(KERN_DEBUG
"kstat_irqs ==> [%#lx - %#lx]\n", phys
, phys
+ total_bytes
);
109 for (i
= 0; i
< nr_desc
; i
++) {
110 desc
[i
].kstat_irqs
= (unsigned int *)ptr
;
116 static void __init
init_work(void *data
)
118 struct dyn_array
*da
= data
;
120 struct irq_desc
*desc
;
124 for (i
= 0; i
< *da
->nr
; i
++) {
125 init_one_irq_desc(&desc
[i
]);
126 #ifndef CONFIG_HAVE_SPARSE_IRQ
131 #ifdef CONFIG_HAVE_SPARSE_IRQ
132 for (i
= 1; i
< *da
->nr
; i
++)
133 desc
[i
-1].next
= &desc
[i
];
136 /* init kstat_irqs, nr_cpu_ids is ready already */
137 init_kstat_irqs(desc
, *da
->nr
, nr_cpu_ids
);
140 #ifdef CONFIG_HAVE_SPARSE_IRQ
141 static int nr_irq_desc
= 32;
143 static int __init
parse_nr_irq_desc(char *arg
)
146 nr_irq_desc
= simple_strtoul(arg
, NULL
, 0);
150 early_param("nr_irq_desc", parse_nr_irq_desc
);
152 static struct irq_desc
*sparse_irqs
;
153 DEFINE_DYN_ARRAY(sparse_irqs
, sizeof(struct irq_desc
), nr_irq_desc
, PAGE_SIZE
, init_work
);
155 struct irq_desc
*irq_to_desc(unsigned int irq
)
157 struct irq_desc
*desc
, *desc_pri
;
161 unsigned long total_bytes
;
165 desc_pri
= desc
= &sparse_irqs
[0];
167 if (desc
->irq
== irq
)
170 if (desc
->irq
== -1U) {
180 * we run out of pre-allocate ones, allocate more
182 printk(KERN_DEBUG
"try to get more irq_desc %d\n", nr_irq_desc
);
184 total_bytes
= sizeof(struct irq_desc
) * nr_irq_desc
;
186 desc
= kzalloc(total_bytes
, GFP_ATOMIC
);
188 desc
= __alloc_bootmem_nopanic(total_bytes
, PAGE_SIZE
, 0);
191 panic("please boot with nr_irq_desc= %d\n", count
* 2);
194 printk(KERN_DEBUG
"irq_desc ==> [%#lx - %#lx]\n", phys
, phys
+ total_bytes
);
196 for (i
= 0; i
< nr_irq_desc
; i
++)
197 init_one_irq_desc(&desc
[i
]);
199 for (i
= 1; i
< nr_irq_desc
; i
++)
200 desc
[i
-1].next
= &desc
[i
];
202 /* init kstat_irqs, nr_cpu_ids is ready already */
203 init_kstat_irqs(desc
, nr_irq_desc
, nr_cpu_ids
);
206 desc_pri
->next
= desc
;
212 static struct irq_desc
*irq_desc
;
213 DEFINE_DYN_ARRAY(irq_desc
, sizeof(struct irq_desc
), nr_irqs
, PAGE_SIZE
, init_work
);
219 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
220 [0 ... NR_IRQS
-1] = {
221 .status
= IRQ_DISABLED
,
222 .chip
= &no_irq_chip
,
223 .handle_irq
= handle_bad_irq
,
225 .lock
= __SPIN_LOCK_UNLOCKED(sparse_irqs
->lock
),
227 .affinity
= CPU_MASK_ALL
234 #ifndef CONFIG_HAVE_SPARSE_IRQ
235 struct irq_desc
*irq_to_desc(unsigned int irq
)
238 return &irq_desc
[irq
];
245 * What should we do if we get a hw irq event on an illegal vector?
246 * Each architecture has to answer this themself.
248 static void ack_bad(unsigned int irq
)
250 struct irq_desc
*desc
;
252 desc
= irq_to_desc(irq
);
253 print_irq_desc(irq
, desc
);
260 static void noop(unsigned int irq
)
264 static unsigned int noop_ret(unsigned int irq
)
270 * Generic no controller implementation
272 struct irq_chip no_irq_chip
= {
283 * Generic dummy implementation which can be used for
284 * real dumb interrupt sources
286 struct irq_chip dummy_irq_chip
= {
299 * Special, empty irq handler:
301 irqreturn_t
no_action(int cpl
, void *dev_id
)
307 * handle_IRQ_event - irq action chain handler
308 * @irq: the interrupt number
309 * @action: the interrupt action chain for this irq
311 * Handles the action chain of an irq event
313 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
315 irqreturn_t ret
, retval
= IRQ_NONE
;
316 unsigned int status
= 0;
318 if (!(action
->flags
& IRQF_DISABLED
))
319 local_irq_enable_in_hardirq();
322 ret
= action
->handler(irq
, action
->dev_id
);
323 if (ret
== IRQ_HANDLED
)
324 status
|= action
->flags
;
326 action
= action
->next
;
329 if (status
& IRQF_SAMPLE_RANDOM
)
330 add_interrupt_randomness(irq
);
336 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
338 * __do_IRQ - original all in one highlevel IRQ handler
339 * @irq: the interrupt number
341 * __do_IRQ handles all normal device IRQ's (the special
342 * SMP cross-CPU interrupts have their own specific
345 * This is the original x86 implementation which is used for every
348 unsigned int __do_IRQ(unsigned int irq
)
350 struct irq_desc
*desc
= irq_to_desc(irq
);
351 struct irqaction
*action
;
354 kstat_irqs_this_cpu(desc
)++;
355 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
356 irqreturn_t action_ret
;
359 * No locking required for CPU-local interrupts:
362 desc
->chip
->ack(irq
);
363 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
364 action_ret
= handle_IRQ_event(irq
, desc
->action
);
366 note_interrupt(irq
, desc
, action_ret
);
368 desc
->chip
->end(irq
);
372 spin_lock(&desc
->lock
);
374 desc
->chip
->ack(irq
);
376 * REPLAY is when Linux resends an IRQ that was dropped earlier
377 * WAITING is used by probe to mark irqs that are being tested
379 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
380 status
|= IRQ_PENDING
; /* we _want_ to handle it */
383 * If the IRQ is disabled for whatever reason, we cannot
384 * use the action we have.
387 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
388 action
= desc
->action
;
389 status
&= ~IRQ_PENDING
; /* we commit to handling */
390 status
|= IRQ_INPROGRESS
; /* we are handling it */
392 desc
->status
= status
;
395 * If there is no IRQ handler or it was disabled, exit early.
396 * Since we set PENDING, if another processor is handling
397 * a different instance of this same irq, the other processor
398 * will take care of it.
400 if (unlikely(!action
))
404 * Edge triggered interrupts need to remember
406 * This applies to any hw interrupts that allow a second
407 * instance of the same irq to arrive while we are in do_IRQ
408 * or in the handler. But the code here only handles the _second_
409 * instance of the irq, not the third or fourth. So it is mostly
410 * useful for irq hardware that does not mask cleanly in an
414 irqreturn_t action_ret
;
416 spin_unlock(&desc
->lock
);
418 action_ret
= handle_IRQ_event(irq
, action
);
420 note_interrupt(irq
, desc
, action_ret
);
422 spin_lock(&desc
->lock
);
423 if (likely(!(desc
->status
& IRQ_PENDING
)))
425 desc
->status
&= ~IRQ_PENDING
;
427 desc
->status
&= ~IRQ_INPROGRESS
;
431 * The ->end() handler has to deal with interrupts which got
432 * disabled while the handler was running.
434 desc
->chip
->end(irq
);
435 spin_unlock(&desc
->lock
);
442 #ifdef CONFIG_TRACE_IRQFLAGS
443 void early_init_irq_lock_class(void)
445 #ifndef CONFIG_HAVE_DYN_ARRAY
448 for (i
= 0; i
< nr_irqs
; i
++)
449 lockdep_set_class(&irq_desc
[i
].lock
, &irq_desc_lock_class
);
454 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
456 struct irq_desc
*desc
= irq_to_desc(irq
);
457 return desc
->kstat_irqs
[cpu
];
459 EXPORT_SYMBOL(kstat_irqs_cpu
);