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_this_cpu
.irqs
[irq
]++;
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 #ifdef CONFIG_HAVE_SPARSE_IRQ
84 static int nr_irq_desc
= 32;
86 static int __init
parse_nr_irq_desc(char *arg
)
89 nr_irq_desc
= simple_strtoul(arg
, NULL
, 0);
93 early_param("nr_irq_desc", parse_nr_irq_desc
);
95 static void __init
init_work(void *data
)
97 struct dyn_array
*da
= data
;
99 struct irq_desc
*desc
;
103 for (i
= 0; i
< *da
->nr
; i
++)
104 init_one_irq_desc(&desc
[i
]);
106 for (i
= 1; i
< *da
->nr
; i
++)
107 desc
[i
-1].next
= &desc
[i
];
110 static struct irq_desc
*sparse_irqs
;
111 DEFINE_DYN_ARRAY(sparse_irqs
, sizeof(struct irq_desc
), nr_irq_desc
, PAGE_SIZE
, init_work
);
113 extern int after_bootmem
;
114 extern void *__alloc_bootmem_nopanic(unsigned long size
,
117 struct irq_desc
*irq_to_desc(unsigned int irq
)
119 struct irq_desc
*desc
, *desc_pri
;
125 desc_pri
= desc
= &sparse_irqs
[0];
127 if (desc
->irq
== irq
)
130 if (desc
->irq
== -1U) {
140 * we run out of pre-allocate ones, allocate more
142 printk(KERN_DEBUG
"try to get more irq_desc %d\n", nr_irq_desc
);
145 desc
= kzalloc(sizeof(struct irq_desc
)*nr_irq_desc
, GFP_ATOMIC
);
147 desc
= __alloc_bootmem_nopanic(sizeof(struct irq_desc
)*nr_irq_desc
, PAGE_SIZE
, 0);
150 panic("please boot with nr_irq_desc= %d\n", count
* 2);
152 for (i
= 0; i
< nr_irq_desc
; i
++)
153 init_one_irq_desc(&desc
[i
]);
155 for (i
= 1; i
< nr_irq_desc
; i
++)
156 desc
[i
-1].next
= &desc
[i
];
159 desc_pri
->next
= desc
;
164 static void __init
init_work(void *data
)
166 struct dyn_array
*da
= data
;
168 struct irq_desc
*desc
;
172 for (i
= 0; i
< *da
->nr
; i
++)
173 init_one_irq_desc(&desc
[i
]);
176 static struct irq_desc
*irq_desc
;
177 DEFINE_DYN_ARRAY(irq_desc
, sizeof(struct irq_desc
), nr_irqs
, PAGE_SIZE
, init_work
);
183 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
184 [0 ... NR_IRQS
-1] = {
185 .status
= IRQ_DISABLED
,
186 .chip
= &no_irq_chip
,
187 .handle_irq
= handle_bad_irq
,
189 .lock
= __SPIN_LOCK_UNLOCKED(sparse_irqs
->lock
),
191 .affinity
= CPU_MASK_ALL
198 #ifndef CONFIG_HAVE_SPARSE_IRQ
199 struct irq_desc
*irq_to_desc(unsigned int irq
)
202 return &irq_desc
[irq
];
209 * What should we do if we get a hw irq event on an illegal vector?
210 * Each architecture has to answer this themself.
212 static void ack_bad(unsigned int irq
)
214 struct irq_desc
*desc
;
216 desc
= irq_to_desc(irq
);
217 print_irq_desc(irq
, desc
);
224 static void noop(unsigned int irq
)
228 static unsigned int noop_ret(unsigned int irq
)
234 * Generic no controller implementation
236 struct irq_chip no_irq_chip
= {
247 * Generic dummy implementation which can be used for
248 * real dumb interrupt sources
250 struct irq_chip dummy_irq_chip
= {
263 * Special, empty irq handler:
265 irqreturn_t
no_action(int cpl
, void *dev_id
)
271 * handle_IRQ_event - irq action chain handler
272 * @irq: the interrupt number
273 * @action: the interrupt action chain for this irq
275 * Handles the action chain of an irq event
277 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
279 irqreturn_t ret
, retval
= IRQ_NONE
;
280 unsigned int status
= 0;
282 if (!(action
->flags
& IRQF_DISABLED
))
283 local_irq_enable_in_hardirq();
286 ret
= action
->handler(irq
, action
->dev_id
);
287 if (ret
== IRQ_HANDLED
)
288 status
|= action
->flags
;
290 action
= action
->next
;
293 if (status
& IRQF_SAMPLE_RANDOM
)
294 add_interrupt_randomness(irq
);
300 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
302 * __do_IRQ - original all in one highlevel IRQ handler
303 * @irq: the interrupt number
305 * __do_IRQ handles all normal device IRQ's (the special
306 * SMP cross-CPU interrupts have their own specific
309 * This is the original x86 implementation which is used for every
312 unsigned int __do_IRQ(unsigned int irq
)
314 struct irq_desc
*desc
= irq_to_desc(irq
);
315 struct irqaction
*action
;
318 kstat_this_cpu
.irqs
[irq
]++;
319 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
320 irqreturn_t action_ret
;
323 * No locking required for CPU-local interrupts:
326 desc
->chip
->ack(irq
);
327 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
328 action_ret
= handle_IRQ_event(irq
, desc
->action
);
330 note_interrupt(irq
, desc
, action_ret
);
332 desc
->chip
->end(irq
);
336 spin_lock(&desc
->lock
);
338 desc
->chip
->ack(irq
);
340 * REPLAY is when Linux resends an IRQ that was dropped earlier
341 * WAITING is used by probe to mark irqs that are being tested
343 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
344 status
|= IRQ_PENDING
; /* we _want_ to handle it */
347 * If the IRQ is disabled for whatever reason, we cannot
348 * use the action we have.
351 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
352 action
= desc
->action
;
353 status
&= ~IRQ_PENDING
; /* we commit to handling */
354 status
|= IRQ_INPROGRESS
; /* we are handling it */
356 desc
->status
= status
;
359 * If there is no IRQ handler or it was disabled, exit early.
360 * Since we set PENDING, if another processor is handling
361 * a different instance of this same irq, the other processor
362 * will take care of it.
364 if (unlikely(!action
))
368 * Edge triggered interrupts need to remember
370 * This applies to any hw interrupts that allow a second
371 * instance of the same irq to arrive while we are in do_IRQ
372 * or in the handler. But the code here only handles the _second_
373 * instance of the irq, not the third or fourth. So it is mostly
374 * useful for irq hardware that does not mask cleanly in an
378 irqreturn_t action_ret
;
380 spin_unlock(&desc
->lock
);
382 action_ret
= handle_IRQ_event(irq
, action
);
384 note_interrupt(irq
, desc
, action_ret
);
386 spin_lock(&desc
->lock
);
387 if (likely(!(desc
->status
& IRQ_PENDING
)))
389 desc
->status
&= ~IRQ_PENDING
;
391 desc
->status
&= ~IRQ_INPROGRESS
;
395 * The ->end() handler has to deal with interrupts which got
396 * disabled while the handler was running.
398 desc
->chip
->end(irq
);
399 spin_unlock(&desc
->lock
);
406 #ifdef CONFIG_TRACE_IRQFLAGS
407 void early_init_irq_lock_class(void)
409 #ifndef CONFIG_HAVE_DYN_ARRAY
412 for (i
= 0; i
< nr_irqs
; i
++)
413 lockdep_set_class(&irq_desc
[i
].lock
, &irq_desc_lock_class
);