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"
22 * lockdep: we want to handle all irq_desc locks as a single lock-class:
24 static struct lock_class_key irq_desc_lock_class;
27 * handle_bad_irq - handle spurious and unhandled irqs
28 * @irq: the interrupt number
29 * @desc: description of the interrupt
31 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
34 handle_bad_irq(unsigned int irq, struct irq_desc *desc)
36 print_irq_desc(irq, desc);
37 #ifdef CONFIG_HAVE_DYN_ARRAY
38 kstat_irqs_this_cpu(desc)++;
40 kstat_irqs_this_cpu(irq)++;
46 * Linux has a controller-independent interrupt architecture.
47 * Every controller has a 'controller-template', that is used
48 * by the main code to do the right thing. Each driver-visible
49 * interrupt source is transparently wired to the appropriate
50 * controller. Thus drivers need not be aware of the
51 * interrupt-controller.
53 * The code is designed to be easily extended with new/different
54 * interrupt controllers, without having to do assembly magic or
55 * having to touch the generic code.
57 * Controller mappings for all interrupt sources:
59 int nr_irqs = NR_IRQS;
60 EXPORT_SYMBOL_GPL(nr_irqs);
62 #ifdef CONFIG_HAVE_DYN_ARRAY
63 static struct irq_desc irq_desc_init = {
65 .status = IRQ_DISABLED,
67 .handle_irq = handle_bad_irq,
69 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
71 .affinity = CPU_MASK_ALL
76 static void init_one_irq_desc(struct irq_desc *desc)
78 memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
79 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
82 extern int after_bootmem;
83 extern void *__alloc_bootmem_nopanic(unsigned long size,
87 static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
89 unsigned long bytes, total_bytes;
94 /* Compute how many bytes we need per irq and allocate them */
95 bytes = nr * sizeof(unsigned int);
96 total_bytes = bytes * nr_desc;
98 ptr = kzalloc(total_bytes, GFP_ATOMIC);
100 ptr = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
103 panic(" can not allocate kstat_irqs\n");
106 printk(KERN_DEBUG "kstat_irqs ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
108 for (i = 0; i < nr_desc; i++) {
109 desc[i].kstat_irqs = (unsigned int *)ptr;
115 * Protect the sparse_irqs_free freelist:
117 static DEFINE_SPINLOCK(sparse_irq_lock);
119 #ifdef CONFIG_HAVE_SPARSE_IRQ
120 static struct irq_desc *sparse_irqs_free;
121 struct irq_desc *sparse_irqs;
124 static void __init init_work(void *data)
126 struct dyn_array *da = data;
128 struct irq_desc *desc;
132 for (i = 0; i < *da->nr; i++) {
133 init_one_irq_desc(&desc[i]);
134 #ifndef CONFIG_HAVE_SPARSE_IRQ
139 /* init kstat_irqs, nr_cpu_ids is ready already */
140 init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
142 #ifdef CONFIG_HAVE_SPARSE_IRQ
143 for (i = 1; i < *da->nr; i++)
144 desc[i-1].next = &desc[i];
146 sparse_irqs_free = sparse_irqs;
151 #ifdef CONFIG_HAVE_SPARSE_IRQ
152 static int nr_irq_desc = 32;
154 static int __init parse_nr_irq_desc(char *arg)
157 nr_irq_desc = simple_strtoul(arg, NULL, 0);
161 early_param("nr_irq_desc", parse_nr_irq_desc);
163 DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc, PAGE_SIZE, init_work);
165 struct irq_desc *irq_to_desc(unsigned int irq)
167 struct irq_desc *desc;
171 if (desc->irq == irq)
179 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
181 struct irq_desc *desc, *desc_pri;
186 desc_pri = desc = sparse_irqs;
188 if (desc->irq == irq)
196 spin_lock_irqsave(&sparse_irq_lock, flags);
198 * we run out of pre-allocate ones, allocate more
200 if (!sparse_irqs_free) {
202 unsigned long total_bytes;
204 printk(KERN_DEBUG "try to get more irq_desc %d\n", nr_irq_desc);
206 total_bytes = sizeof(struct irq_desc) * nr_irq_desc;
208 desc = kzalloc(total_bytes, GFP_ATOMIC);
210 desc = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
213 panic("please boot with nr_irq_desc= %d\n", count * 2);
216 printk(KERN_DEBUG "irq_desc ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
218 for (i = 0; i < nr_irq_desc; i++)
219 init_one_irq_desc(&desc[i]);
221 for (i = 1; i < nr_irq_desc; i++)
222 desc[i-1].next = &desc[i];
224 /* init kstat_irqs, nr_cpu_ids is ready already */
225 init_kstat_irqs(desc, nr_irq_desc, nr_cpu_ids);
227 sparse_irqs_free = desc;
230 desc = sparse_irqs_free;
231 sparse_irqs_free = sparse_irqs_free->next;
234 desc_pri->next = desc;
239 spin_unlock_irqrestore(&sparse_irq_lock, flags);
244 struct irq_desc *irq_desc;
245 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
251 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
252 [0 ... NR_IRQS-1] = {
253 .status = IRQ_DISABLED,
254 .chip = &no_irq_chip,
255 .handle_irq = handle_bad_irq,
257 .lock = __SPIN_LOCK_UNLOCKED(sparse_irqs->lock),
259 .affinity = CPU_MASK_ALL
266 #ifndef CONFIG_HAVE_SPARSE_IRQ
267 struct irq_desc *irq_to_desc(unsigned int irq)
270 return &irq_desc[irq];
274 struct irq_desc *irq_to_desc_alloc(unsigned int irq)
276 return irq_to_desc(irq);
281 * What should we do if we get a hw irq event on an illegal vector?
282 * Each architecture has to answer this themself.
284 static void ack_bad(unsigned int irq)
286 struct irq_desc *desc;
288 desc = irq_to_desc(irq);
289 print_irq_desc(irq, desc);
296 static void noop(unsigned int irq)
300 static unsigned int noop_ret(unsigned int irq)
306 * Generic no controller implementation
308 struct irq_chip no_irq_chip = {
319 * Generic dummy implementation which can be used for
320 * real dumb interrupt sources
322 struct irq_chip dummy_irq_chip = {
335 * Special, empty irq handler:
337 irqreturn_t no_action(int cpl, void *dev_id)
343 * handle_IRQ_event - irq action chain handler
344 * @irq: the interrupt number
345 * @action: the interrupt action chain for this irq
347 * Handles the action chain of an irq event
349 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
351 irqreturn_t ret, retval = IRQ_NONE;
352 unsigned int status = 0;
354 if (!(action->flags & IRQF_DISABLED))
355 local_irq_enable_in_hardirq();
358 ret = action->handler(irq, action->dev_id);
359 if (ret == IRQ_HANDLED)
360 status |= action->flags;
362 action = action->next;
365 if (status & IRQF_SAMPLE_RANDOM)
366 add_interrupt_randomness(irq);
372 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
374 * __do_IRQ - original all in one highlevel IRQ handler
375 * @irq: the interrupt number
377 * __do_IRQ handles all normal device IRQ's (the special
378 * SMP cross-CPU interrupts have their own specific
381 * This is the original x86 implementation which is used for every
384 unsigned int __do_IRQ(unsigned int irq)
386 struct irq_desc *desc = irq_to_desc(irq);
387 struct irqaction *action;
390 #ifdef CONFIG_HAVE_DYN_ARRAY
391 kstat_irqs_this_cpu(desc)++;
393 kstat_irqs_this_cpu(irq)++;
395 if (CHECK_IRQ_PER_CPU(desc->status)) {
396 irqreturn_t action_ret;
399 * No locking required for CPU-local interrupts:
402 desc->chip->ack(irq);
403 if (likely(!(desc->status & IRQ_DISABLED))) {
404 action_ret = handle_IRQ_event(irq, desc->action);
406 note_interrupt(irq, desc, action_ret);
408 desc->chip->end(irq);
412 spin_lock(&desc->lock);
414 desc->chip->ack(irq);
416 * REPLAY is when Linux resends an IRQ that was dropped earlier
417 * WAITING is used by probe to mark irqs that are being tested
419 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
420 status |= IRQ_PENDING; /* we _want_ to handle it */
423 * If the IRQ is disabled for whatever reason, we cannot
424 * use the action we have.
427 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
428 action = desc->action;
429 status &= ~IRQ_PENDING; /* we commit to handling */
430 status |= IRQ_INPROGRESS; /* we are handling it */
432 desc->status = status;
435 * If there is no IRQ handler or it was disabled, exit early.
436 * Since we set PENDING, if another processor is handling
437 * a different instance of this same irq, the other processor
438 * will take care of it.
440 if (unlikely(!action))
444 * Edge triggered interrupts need to remember
446 * This applies to any hw interrupts that allow a second
447 * instance of the same irq to arrive while we are in do_IRQ
448 * or in the handler. But the code here only handles the _second_
449 * instance of the irq, not the third or fourth. So it is mostly
450 * useful for irq hardware that does not mask cleanly in an
454 irqreturn_t action_ret;
456 spin_unlock(&desc->lock);
458 action_ret = handle_IRQ_event(irq, action);
460 note_interrupt(irq, desc, action_ret);
462 spin_lock(&desc->lock);
463 if (likely(!(desc->status & IRQ_PENDING)))
465 desc->status &= ~IRQ_PENDING;
467 desc->status &= ~IRQ_INPROGRESS;
471 * The ->end() handler has to deal with interrupts which got
472 * disabled while the handler was running.
474 desc->chip->end(irq);
475 spin_unlock(&desc->lock);
482 #ifdef CONFIG_TRACE_IRQFLAGS
483 void early_init_irq_lock_class(void)
485 #ifndef CONFIG_HAVE_DYN_ARRAY
488 for (i = 0; i < nr_irqs; i++)
489 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
494 #ifdef CONFIG_HAVE_DYN_ARRAY
495 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
497 struct irq_desc *desc = irq_to_desc(irq);
498 return desc->kstat_irqs[cpu];
501 EXPORT_SYMBOL(kstat_irqs_cpu);