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
61 static struct irq_desc irq_desc_init = {
63 .status = IRQ_DISABLED,
65 .handle_irq = handle_bad_irq,
67 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
70 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
76 /* Compute how many bytes we need per irq and allocate them */
77 bytes = nr * sizeof(unsigned int);
79 node = cpu_to_node(cpu);
80 ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
81 printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n", cpu, node);
84 desc->kstat_irqs = (unsigned int *)ptr;
87 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
89 memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
91 spin_lock_init(&desc->lock);
96 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
97 init_kstat_irqs(desc, cpu, nr_cpu_ids);
98 if (!desc->kstat_irqs) {
99 printk(KERN_ERR "can not alloc kstat_irqs\n");
102 if (!init_alloc_desc_masks(desc, cpu, false)) {
103 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
106 arch_init_chip_data(desc, cpu);
110 * Protect the sparse_irqs:
112 DEFINE_SPINLOCK(sparse_irq_lock);
114 struct irq_desc **irq_desc_ptrs __read_mostly;
116 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
117 [0 ... NR_IRQS_LEGACY-1] = {
119 .status = IRQ_DISABLED,
120 .chip = &no_irq_chip,
121 .handle_irq = handle_bad_irq,
123 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
127 /* FIXME: use bootmem alloc ...*/
128 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
130 int __init early_irq_init(void)
132 struct irq_desc *desc;
136 /* initialize nr_irqs based on nr_cpu_ids */
137 nr_irqs = max_nr_irqs(nr_cpu_ids);
139 printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
141 desc = irq_desc_legacy;
142 legacy_count = ARRAY_SIZE(irq_desc_legacy);
144 /* allocate irq_desc_ptrs array based on nr_irqs */
145 irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
147 for (i = 0; i < legacy_count; i++) {
149 desc[i].kstat_irqs = kstat_irqs_legacy[i];
150 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
151 init_alloc_desc_masks(&desc[i], 0, true);
152 irq_desc_ptrs[i] = desc + i;
155 for (i = legacy_count; i < nr_irqs; i++)
156 irq_desc_ptrs[i] = NULL;
158 return arch_early_irq_init();
161 struct irq_desc *irq_to_desc(unsigned int irq)
163 if (irq_desc_ptrs && irq < nr_irqs)
164 return irq_desc_ptrs[irq];
169 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
171 struct irq_desc *desc;
175 if (irq >= nr_irqs) {
176 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
181 desc = irq_desc_ptrs[irq];
185 spin_lock_irqsave(&sparse_irq_lock, flags);
187 /* We have to check it to avoid races with another CPU */
188 desc = irq_desc_ptrs[irq];
192 node = cpu_to_node(cpu);
193 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
194 printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
197 printk(KERN_ERR "can not alloc irq_desc\n");
200 init_one_irq_desc(irq, desc, cpu);
202 irq_desc_ptrs[irq] = desc;
205 spin_unlock_irqrestore(&sparse_irq_lock, flags);
210 #else /* !CONFIG_SPARSE_IRQ */
212 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
213 [0 ... NR_IRQS-1] = {
214 .status = IRQ_DISABLED,
215 .chip = &no_irq_chip,
216 .handle_irq = handle_bad_irq,
218 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
222 int __init early_irq_init(void)
224 struct irq_desc *desc;
228 printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
231 count = ARRAY_SIZE(irq_desc);
233 for (i = 0; i < count; i++) {
235 init_alloc_desc_masks(&desc[i], 0, true);
237 return arch_early_irq_init();
240 struct irq_desc *irq_to_desc(unsigned int irq)
242 return (irq < NR_IRQS) ? irq_desc + irq : NULL;
245 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
247 return irq_to_desc(irq);
249 #endif /* !CONFIG_SPARSE_IRQ */
252 * What should we do if we get a hw irq event on an illegal vector?
253 * Each architecture has to answer this themself.
255 static void ack_bad(unsigned int irq)
257 struct irq_desc *desc = irq_to_desc(irq);
259 print_irq_desc(irq, desc);
266 static void noop(unsigned int irq)
270 static unsigned int noop_ret(unsigned int irq)
276 * Generic no controller implementation
278 struct irq_chip no_irq_chip = {
289 * Generic dummy implementation which can be used for
290 * real dumb interrupt sources
292 struct irq_chip dummy_irq_chip = {
305 * Special, empty irq handler:
307 irqreturn_t no_action(int cpl, void *dev_id)
313 * handle_IRQ_event - irq action chain handler
314 * @irq: the interrupt number
315 * @action: the interrupt action chain for this irq
317 * Handles the action chain of an irq event
319 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
321 irqreturn_t ret, retval = IRQ_NONE;
322 unsigned int status = 0;
324 if (!(action->flags & IRQF_DISABLED))
325 local_irq_enable_in_hardirq();
328 ret = action->handler(irq, action->dev_id);
329 if (ret == IRQ_HANDLED)
330 status |= action->flags;
332 action = action->next;
335 if (status & IRQF_SAMPLE_RANDOM)
336 add_interrupt_randomness(irq);
342 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
344 * __do_IRQ - original all in one highlevel IRQ handler
345 * @irq: the interrupt number
347 * __do_IRQ handles all normal device IRQ's (the special
348 * SMP cross-CPU interrupts have their own specific
351 * This is the original x86 implementation which is used for every
354 unsigned int __do_IRQ(unsigned int irq)
356 struct irq_desc *desc = irq_to_desc(irq);
357 struct irqaction *action;
360 kstat_incr_irqs_this_cpu(irq, desc);
362 if (CHECK_IRQ_PER_CPU(desc->status)) {
363 irqreturn_t action_ret;
366 * No locking required for CPU-local interrupts:
368 if (desc->chip->ack) {
369 desc->chip->ack(irq);
371 desc = irq_remap_to_desc(irq, desc);
373 if (likely(!(desc->status & IRQ_DISABLED))) {
374 action_ret = handle_IRQ_event(irq, desc->action);
376 note_interrupt(irq, desc, action_ret);
378 desc->chip->end(irq);
382 spin_lock(&desc->lock);
383 if (desc->chip->ack) {
384 desc->chip->ack(irq);
385 desc = irq_remap_to_desc(irq, desc);
388 * REPLAY is when Linux resends an IRQ that was dropped earlier
389 * WAITING is used by probe to mark irqs that are being tested
391 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
392 status |= IRQ_PENDING; /* we _want_ to handle it */
395 * If the IRQ is disabled for whatever reason, we cannot
396 * use the action we have.
399 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
400 action = desc->action;
401 status &= ~IRQ_PENDING; /* we commit to handling */
402 status |= IRQ_INPROGRESS; /* we are handling it */
404 desc->status = status;
407 * If there is no IRQ handler or it was disabled, exit early.
408 * Since we set PENDING, if another processor is handling
409 * a different instance of this same irq, the other processor
410 * will take care of it.
412 if (unlikely(!action))
416 * Edge triggered interrupts need to remember
418 * This applies to any hw interrupts that allow a second
419 * instance of the same irq to arrive while we are in do_IRQ
420 * or in the handler. But the code here only handles the _second_
421 * instance of the irq, not the third or fourth. So it is mostly
422 * useful for irq hardware that does not mask cleanly in an
426 irqreturn_t action_ret;
428 spin_unlock(&desc->lock);
430 action_ret = handle_IRQ_event(irq, action);
432 note_interrupt(irq, desc, action_ret);
434 spin_lock(&desc->lock);
435 if (likely(!(desc->status & IRQ_PENDING)))
437 desc->status &= ~IRQ_PENDING;
439 desc->status &= ~IRQ_INPROGRESS;
443 * The ->end() handler has to deal with interrupts which got
444 * disabled while the handler was running.
446 desc->chip->end(irq);
447 spin_unlock(&desc->lock);
453 void early_init_irq_lock_class(void)
455 struct irq_desc *desc;
458 for_each_irq_desc(i, desc) {
459 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
463 #ifdef CONFIG_SPARSE_IRQ
464 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
466 struct irq_desc *desc = irq_to_desc(irq);
467 return desc ? desc->kstat_irqs[cpu] : 0;
470 EXPORT_SYMBOL(kstat_irqs_cpu);