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>
20 #include <linux/bootmem.h>
22 #include "internals.h"
25 * lockdep: we want to handle all irq_desc locks as a single lock-class:
27 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.
36 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
38 print_irq_desc(irq, desc);
39 kstat_incr_irqs_this_cpu(irq, desc);
44 * Linux has a controller-independent interrupt architecture.
45 * Every controller has a 'controller-template', that is used
46 * by the main code to do the right thing. Each driver-visible
47 * interrupt source is transparently wired to the appropriate
48 * controller. Thus drivers need not be aware of the
49 * interrupt-controller.
51 * The code is designed to be easily extended with new/different
52 * interrupt controllers, without having to do assembly magic or
53 * having to touch the generic code.
55 * Controller mappings for all interrupt sources:
57 int nr_irqs = NR_IRQS;
58 EXPORT_SYMBOL_GPL(nr_irqs);
60 #ifdef CONFIG_SPARSE_IRQ
63 #define max_nr_irqs(nr_cpus) NR_IRQS
66 static struct irq_desc irq_desc_init = {
68 .status = IRQ_DISABLED,
70 .handle_irq = handle_bad_irq,
72 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
75 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
81 /* Compute how many bytes we need per irq and allocate them */
82 bytes = nr * sizeof(unsigned int);
84 node = cpu_to_node(cpu);
85 ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
86 printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n", cpu, node);
89 desc->kstat_irqs = (unsigned int *)ptr;
92 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
94 memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
96 spin_lock_init(&desc->lock);
101 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
102 init_kstat_irqs(desc, cpu, nr_cpu_ids);
103 if (!desc->kstat_irqs) {
104 printk(KERN_ERR "can not alloc kstat_irqs\n");
107 if (!init_alloc_desc_masks(desc, cpu, false)) {
108 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
111 arch_init_chip_data(desc, cpu);
115 * Protect the sparse_irqs:
117 DEFINE_SPINLOCK(sparse_irq_lock);
119 struct irq_desc **irq_desc_ptrs __read_mostly;
121 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
122 [0 ... NR_IRQS_LEGACY-1] = {
124 .status = IRQ_DISABLED,
125 .chip = &no_irq_chip,
126 .handle_irq = handle_bad_irq,
128 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
132 static unsigned int *kstat_irqs_legacy;
134 int __init early_irq_init(void)
136 struct irq_desc *desc;
140 /* initialize nr_irqs based on nr_cpu_ids */
141 nr_irqs = max_nr_irqs(nr_cpu_ids);
143 printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
145 desc = irq_desc_legacy;
146 legacy_count = ARRAY_SIZE(irq_desc_legacy);
148 /* allocate irq_desc_ptrs array based on nr_irqs */
149 irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
151 /* allocate based on nr_cpu_ids */
152 /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
153 kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
156 for (i = 0; i < legacy_count; i++) {
158 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
159 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
160 init_alloc_desc_masks(&desc[i], 0, true);
161 irq_desc_ptrs[i] = desc + i;
164 for (i = legacy_count; i < nr_irqs; i++)
165 irq_desc_ptrs[i] = NULL;
167 return arch_early_irq_init();
170 struct irq_desc *irq_to_desc(unsigned int irq)
172 if (irq_desc_ptrs && irq < nr_irqs)
173 return irq_desc_ptrs[irq];
178 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
180 struct irq_desc *desc;
184 if (irq >= nr_irqs) {
185 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
190 desc = irq_desc_ptrs[irq];
194 spin_lock_irqsave(&sparse_irq_lock, flags);
196 /* We have to check it to avoid races with another CPU */
197 desc = irq_desc_ptrs[irq];
201 node = cpu_to_node(cpu);
202 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
203 printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
206 printk(KERN_ERR "can not alloc irq_desc\n");
209 init_one_irq_desc(irq, desc, cpu);
211 irq_desc_ptrs[irq] = desc;
214 spin_unlock_irqrestore(&sparse_irq_lock, flags);
219 #else /* !CONFIG_SPARSE_IRQ */
221 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
222 [0 ... NR_IRQS-1] = {
223 .status = IRQ_DISABLED,
224 .chip = &no_irq_chip,
225 .handle_irq = handle_bad_irq,
227 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
231 int __init early_irq_init(void)
233 struct irq_desc *desc;
237 printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
240 count = ARRAY_SIZE(irq_desc);
242 for (i = 0; i < count; i++) {
244 init_alloc_desc_masks(&desc[i], 0, true);
246 return arch_early_irq_init();
249 struct irq_desc *irq_to_desc(unsigned int irq)
251 return (irq < NR_IRQS) ? irq_desc + irq : NULL;
254 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
256 return irq_to_desc(irq);
258 #endif /* !CONFIG_SPARSE_IRQ */
261 * What should we do if we get a hw irq event on an illegal vector?
262 * Each architecture has to answer this themself.
264 static void ack_bad(unsigned int irq)
266 struct irq_desc *desc = irq_to_desc(irq);
268 print_irq_desc(irq, desc);
275 static void noop(unsigned int irq)
279 static unsigned int noop_ret(unsigned int irq)
285 * Generic no controller implementation
287 struct irq_chip no_irq_chip = {
298 * Generic dummy implementation which can be used for
299 * real dumb interrupt sources
301 struct irq_chip dummy_irq_chip = {
314 * Special, empty irq handler:
316 irqreturn_t no_action(int cpl, void *dev_id)
322 * handle_IRQ_event - irq action chain handler
323 * @irq: the interrupt number
324 * @action: the interrupt action chain for this irq
326 * Handles the action chain of an irq event
328 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
330 irqreturn_t ret, retval = IRQ_NONE;
331 unsigned int status = 0;
333 if (!(action->flags & IRQF_DISABLED))
334 local_irq_enable_in_hardirq();
337 ret = action->handler(irq, action->dev_id);
338 if (ret == IRQ_HANDLED)
339 status |= action->flags;
341 action = action->next;
344 if (status & IRQF_SAMPLE_RANDOM)
345 add_interrupt_randomness(irq);
351 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
353 * __do_IRQ - original all in one highlevel IRQ handler
354 * @irq: the interrupt number
356 * __do_IRQ handles all normal device IRQ's (the special
357 * SMP cross-CPU interrupts have their own specific
360 * This is the original x86 implementation which is used for every
363 unsigned int __do_IRQ(unsigned int irq)
365 struct irq_desc *desc = irq_to_desc(irq);
366 struct irqaction *action;
369 kstat_incr_irqs_this_cpu(irq, desc);
371 if (CHECK_IRQ_PER_CPU(desc->status)) {
372 irqreturn_t action_ret;
375 * No locking required for CPU-local interrupts:
377 if (desc->chip->ack) {
378 desc->chip->ack(irq);
380 desc = irq_remap_to_desc(irq, desc);
382 if (likely(!(desc->status & IRQ_DISABLED))) {
383 action_ret = handle_IRQ_event(irq, desc->action);
385 note_interrupt(irq, desc, action_ret);
387 desc->chip->end(irq);
391 spin_lock(&desc->lock);
392 if (desc->chip->ack) {
393 desc->chip->ack(irq);
394 desc = irq_remap_to_desc(irq, desc);
397 * REPLAY is when Linux resends an IRQ that was dropped earlier
398 * WAITING is used by probe to mark irqs that are being tested
400 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
401 status |= IRQ_PENDING; /* we _want_ to handle it */
404 * If the IRQ is disabled for whatever reason, we cannot
405 * use the action we have.
408 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
409 action = desc->action;
410 status &= ~IRQ_PENDING; /* we commit to handling */
411 status |= IRQ_INPROGRESS; /* we are handling it */
413 desc->status = status;
416 * If there is no IRQ handler or it was disabled, exit early.
417 * Since we set PENDING, if another processor is handling
418 * a different instance of this same irq, the other processor
419 * will take care of it.
421 if (unlikely(!action))
425 * Edge triggered interrupts need to remember
427 * This applies to any hw interrupts that allow a second
428 * instance of the same irq to arrive while we are in do_IRQ
429 * or in the handler. But the code here only handles the _second_
430 * instance of the irq, not the third or fourth. So it is mostly
431 * useful for irq hardware that does not mask cleanly in an
435 irqreturn_t action_ret;
437 spin_unlock(&desc->lock);
439 action_ret = handle_IRQ_event(irq, action);
441 note_interrupt(irq, desc, action_ret);
443 spin_lock(&desc->lock);
444 if (likely(!(desc->status & IRQ_PENDING)))
446 desc->status &= ~IRQ_PENDING;
448 desc->status &= ~IRQ_INPROGRESS;
452 * The ->end() handler has to deal with interrupts which got
453 * disabled while the handler was running.
455 desc->chip->end(irq);
456 spin_unlock(&desc->lock);
462 void early_init_irq_lock_class(void)
464 struct irq_desc *desc;
467 for_each_irq_desc(i, desc) {
468 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
472 #ifdef CONFIG_SPARSE_IRQ
473 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
475 struct irq_desc *desc = irq_to_desc(irq);
476 return desc ? desc->kstat_irqs[cpu] : 0;
479 EXPORT_SYMBOL(kstat_irqs_cpu);