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;
115 #ifdef CONFIG_HAVE_SPARSE_IRQ
116 static struct irq_desc *sparse_irqs_free;
117 struct irq_desc *sparse_irqs;
120 static void __init init_work(void *data)
122 struct dyn_array *da = data;
124 struct irq_desc *desc;
128 for (i = 0; i < *da->nr; i++) {
129 init_one_irq_desc(&desc[i]);
130 #ifndef CONFIG_HAVE_SPARSE_IRQ
135 /* init kstat_irqs, nr_cpu_ids is ready already */
136 init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
138 #ifdef CONFIG_HAVE_SPARSE_IRQ
139 for (i = 1; i < *da->nr; i++)
140 desc[i-1].next = &desc[i];
142 sparse_irqs_free = sparse_irqs;
147 #ifdef CONFIG_HAVE_SPARSE_IRQ
148 static int nr_irq_desc = 32;
150 static int __init parse_nr_irq_desc(char *arg)
153 nr_irq_desc = simple_strtoul(arg, NULL, 0);
157 early_param("nr_irq_desc", parse_nr_irq_desc);
159 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
161 struct irq_desc *irq_to_desc(unsigned int irq)
163 struct irq_desc *desc;
167 if (desc->irq == irq)
174 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
176 struct irq_desc *desc, *desc_pri;
180 desc_pri = desc = sparse_irqs;
182 if (desc->irq == irq)
191 * we run out of pre-allocate ones, allocate more
193 if (!sparse_irqs_free) {
195 unsigned long total_bytes;
197 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
199 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
201 desc = kzalloc(total_bytes, GFP_ATOMIC);
203 desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
206 panic("please boot with nr_irq_desc= %d\n", count * 2);
209 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
211 for (i = 0; i < nr_irq_desc; i++)
212 init_one_irq_desc(&desc[i]);
214 for (i = 1; i < nr_irq_desc; i++)
215 desc[i-1].next = &desc[i];
217 /* init kstat_irqs, nr_cpu_ids is ready already */
218 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
220 sparse_irqs_free = desc;
223 desc = sparse_irqs_free;
224 sparse_irqs_free = sparse_irqs_free->next;
227 desc_pri->next = desc;
231 printk(KERN_DEBUG "found new irq_desc for irq %d\n", desc->irq);
232 #ifdef CONFIG_HAVE_SPARSE_IRQ_DEBUG
234 /* dump the results */
235 struct irq_desc *desc;
237 unsigned long bytes = sizeof(struct irq_desc);
240 printk(KERN_DEBUG "=========================== %d\n", irq);
241 printk(KERN_DEBUG "irq_desc dump after get that for %d\n", irq);
242 for_each_irq_desc(irqx, desc) {
244 printk(KERN_DEBUG "irq_desc %d ==> [%#lx - %#lx]\n", irqx, phys, phys + bytes);
246 printk(KERN_DEBUG "===========================\n");
252 struct irq_desc *irq_desc;
253 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
259 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
260 [0 ... NR_IRQS-1] = {
261 .status = IRQ_DISABLED,
262 .chip = &no_irq_chip,
263 .handle_irq = handle_bad_irq,
265 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
267 .affinity = CPU_MASK_ALL
274 #ifndef CONFIG_HAVE_SPARSE_IRQ
275 struct irq_desc *irq_to_desc(unsigned int irq)
278 return &irq_desc[irq];
282 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
284 return irq_to_desc(irq);
289 * What should we do if we get a hw irq event on an illegal vector?
290 * Each architecture has to answer this themself.
292 static void ack_bad(unsigned int irq)
294 struct irq_desc *desc;
296 desc = irq_to_desc(irq);
297 print_irq_desc(irq, desc);
304 static void noop(unsigned int irq)
308 static unsigned int noop_ret(unsigned int irq)
314 * Generic no controller implementation
316 struct irq_chip no_irq_chip = {
327 * Generic dummy implementation which can be used for
328 * real dumb interrupt sources
330 struct irq_chip dummy_irq_chip = {
343 * Special, empty irq handler:
345 irqreturn_t no_action(int cpl, void *dev_id)
351 * handle_IRQ_event - irq action chain handler
352 * @irq: the interrupt number
353 * @action: the interrupt action chain for this irq
355 * Handles the action chain of an irq event
357 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
359 irqreturn_t ret, retval = IRQ_NONE;
360 unsigned int status = 0;
362 if (!(action->flags & IRQF_DISABLED))
363 local_irq_enable_in_hardirq();
366 ret = action->handler(irq, action->dev_id);
367 if (ret == IRQ_HANDLED)
368 status |= action->flags;
370 action = action->next;
373 if (status & IRQF_SAMPLE_RANDOM)
374 add_interrupt_randomness(irq);
380 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
382 * __do_IRQ - original all in one highlevel IRQ handler
383 * @irq: the interrupt number
385 * __do_IRQ handles all normal device IRQ's (the special
386 * SMP cross-CPU interrupts have their own specific
389 * This is the original x86 implementation which is used for every
392 unsigned int __do_IRQ(unsigned int irq)
394 struct irq_desc *desc = irq_to_desc(irq);
395 struct irqaction *action;
398 kstat_irqs_this_cpu(desc)++;
399 if (CHECK_IRQ_PER_CPU(desc->status)) {
400 irqreturn_t action_ret;
403 * No locking required for CPU-local interrupts:
406 desc->chip->ack(irq);
407 if (likely(!(desc->status & IRQ_DISABLED))) {
408 action_ret = handle_IRQ_event(irq, desc->action);
410 note_interrupt(irq, desc, action_ret);
412 desc->chip->end(irq);
416 spin_lock(&desc->lock);
418 desc->chip->ack(irq);
420 * REPLAY is when Linux resends an IRQ that was dropped earlier
421 * WAITING is used by probe to mark irqs that are being tested
423 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
424 status |= IRQ_PENDING; /* we _want_ to handle it */
427 * If the IRQ is disabled for whatever reason, we cannot
428 * use the action we have.
431 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
432 action = desc->action;
433 status &= ~IRQ_PENDING; /* we commit to handling */
434 status |= IRQ_INPROGRESS; /* we are handling it */
436 desc->status = status;
439 * If there is no IRQ handler or it was disabled, exit early.
440 * Since we set PENDING, if another processor is handling
441 * a different instance of this same irq, the other processor
442 * will take care of it.
444 if (unlikely(!action))
448 * Edge triggered interrupts need to remember
450 * This applies to any hw interrupts that allow a second
451 * instance of the same irq to arrive while we are in do_IRQ
452 * or in the handler. But the code here only handles the _second_
453 * instance of the irq, not the third or fourth. So it is mostly
454 * useful for irq hardware that does not mask cleanly in an
458 irqreturn_t action_ret;
460 spin_unlock(&desc->lock);
462 action_ret = handle_IRQ_event(irq, action);
464 note_interrupt(irq, desc, action_ret);
466 spin_lock(&desc->lock);
467 if (likely(!(desc->status & IRQ_PENDING)))
469 desc->status &= ~IRQ_PENDING;
471 desc->status &= ~IRQ_INPROGRESS;
475 * The ->end() handler has to deal with interrupts which got
476 * disabled while the handler was running.
478 desc->chip->end(irq);
479 spin_unlock(&desc->lock);
486 #ifdef CONFIG_TRACE_IRQFLAGS
487 void early_init_irq_lock_class(void)
489 #ifndef CONFIG_HAVE_DYN_ARRAY
492 for (i = 0; i < nr_irqs; i++)
493 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
498 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
500 struct irq_desc *desc = irq_to_desc(irq);
501 return desc->kstat_irqs[cpu];
503 EXPORT_SYMBOL(kstat_irqs_cpu);