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272 lines
6.2 KiB
272 lines
6.2 KiB
/*
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* linux/kernel/irq/handle.c
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*
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* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
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* Copyright (C) 2005-2006, Thomas Gleixner, Russell King
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*
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* This file contains the core interrupt handling code.
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*
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* Detailed information is available in Documentation/DocBook/genericirq
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*
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*/
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/interrupt.h>
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#include <linux/kernel_stat.h>
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#include "internals.h"
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/**
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* handle_bad_irq - handle spurious and unhandled irqs
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* @irq: the interrupt number
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* @desc: description of the interrupt
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*
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* Handles spurious and unhandled IRQ's. It also prints a debugmessage.
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*/
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void fastcall
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handle_bad_irq(unsigned int irq, struct irq_desc *desc)
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{
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print_irq_desc(irq, desc);
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kstat_this_cpu.irqs[irq]++;
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ack_bad_irq(irq);
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}
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/*
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* Linux has a controller-independent interrupt architecture.
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* Every controller has a 'controller-template', that is used
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* by the main code to do the right thing. Each driver-visible
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* interrupt source is transparently wired to the appropriate
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* controller. Thus drivers need not be aware of the
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* interrupt-controller.
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*
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* The code is designed to be easily extended with new/different
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* interrupt controllers, without having to do assembly magic or
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* having to touch the generic code.
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*
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* Controller mappings for all interrupt sources:
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*/
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struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
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[0 ... NR_IRQS-1] = {
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.status = IRQ_DISABLED,
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.chip = &no_irq_chip,
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.handle_irq = handle_bad_irq,
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.depth = 1,
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.lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
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#ifdef CONFIG_SMP
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.affinity = CPU_MASK_ALL
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#endif
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}
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};
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/*
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* What should we do if we get a hw irq event on an illegal vector?
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* Each architecture has to answer this themself.
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*/
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static void ack_bad(unsigned int irq)
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{
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print_irq_desc(irq, irq_desc + irq);
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ack_bad_irq(irq);
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}
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/*
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* NOP functions
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*/
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static void noop(unsigned int irq)
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{
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}
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static unsigned int noop_ret(unsigned int irq)
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{
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return 0;
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}
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/*
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* Generic no controller implementation
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*/
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struct irq_chip no_irq_chip = {
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.name = "none",
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.startup = noop_ret,
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.shutdown = noop,
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.enable = noop,
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.disable = noop,
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.ack = ack_bad,
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.end = noop,
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};
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/*
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* Generic dummy implementation which can be used for
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* real dumb interrupt sources
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*/
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struct irq_chip dummy_irq_chip = {
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.name = "dummy",
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.startup = noop_ret,
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.shutdown = noop,
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.enable = noop,
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.disable = noop,
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.ack = noop,
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.mask = noop,
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.unmask = noop,
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.end = noop,
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};
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/*
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* Special, empty irq handler:
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*/
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irqreturn_t no_action(int cpl, void *dev_id)
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{
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return IRQ_NONE;
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}
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/**
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* handle_IRQ_event - irq action chain handler
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* @irq: the interrupt number
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* @action: the interrupt action chain for this irq
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*
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* Handles the action chain of an irq event
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*/
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irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
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{
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irqreturn_t ret, retval = IRQ_NONE;
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unsigned int status = 0;
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handle_dynamic_tick(action);
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if (!(action->flags & IRQF_DISABLED))
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local_irq_enable_in_hardirq();
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do {
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ret = action->handler(irq, action->dev_id);
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if (ret == IRQ_HANDLED)
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status |= action->flags;
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retval |= ret;
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action = action->next;
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} while (action);
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if (status & IRQF_SAMPLE_RANDOM)
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add_interrupt_randomness(irq);
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local_irq_disable();
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return retval;
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}
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#ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
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/**
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* __do_IRQ - original all in one highlevel IRQ handler
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* @irq: the interrupt number
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*
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* __do_IRQ handles all normal device IRQ's (the special
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* SMP cross-CPU interrupts have their own specific
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* handlers).
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*
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* This is the original x86 implementation which is used for every
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* interrupt type.
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*/
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fastcall unsigned int __do_IRQ(unsigned int irq)
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{
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struct irq_desc *desc = irq_desc + irq;
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struct irqaction *action;
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unsigned int status;
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kstat_this_cpu.irqs[irq]++;
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if (CHECK_IRQ_PER_CPU(desc->status)) {
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irqreturn_t action_ret;
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/*
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* No locking required for CPU-local interrupts:
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*/
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if (desc->chip->ack)
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desc->chip->ack(irq);
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action_ret = handle_IRQ_event(irq, desc->action);
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if (!noirqdebug)
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note_interrupt(irq, desc, action_ret);
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desc->chip->end(irq);
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return 1;
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}
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spin_lock(&desc->lock);
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if (desc->chip->ack)
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desc->chip->ack(irq);
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/*
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* REPLAY is when Linux resends an IRQ that was dropped earlier
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* WAITING is used by probe to mark irqs that are being tested
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*/
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status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
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status |= IRQ_PENDING; /* we _want_ to handle it */
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/*
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* If the IRQ is disabled for whatever reason, we cannot
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* use the action we have.
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*/
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action = NULL;
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if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
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action = desc->action;
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status &= ~IRQ_PENDING; /* we commit to handling */
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status |= IRQ_INPROGRESS; /* we are handling it */
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}
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desc->status = status;
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/*
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* If there is no IRQ handler or it was disabled, exit early.
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* Since we set PENDING, if another processor is handling
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* a different instance of this same irq, the other processor
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* will take care of it.
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*/
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if (unlikely(!action))
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goto out;
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/*
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* Edge triggered interrupts need to remember
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* pending events.
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* This applies to any hw interrupts that allow a second
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* instance of the same irq to arrive while we are in do_IRQ
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* or in the handler. But the code here only handles the _second_
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* instance of the irq, not the third or fourth. So it is mostly
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* useful for irq hardware that does not mask cleanly in an
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* SMP environment.
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*/
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for (;;) {
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irqreturn_t action_ret;
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spin_unlock(&desc->lock);
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action_ret = handle_IRQ_event(irq, action);
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if (!noirqdebug)
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note_interrupt(irq, desc, action_ret);
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spin_lock(&desc->lock);
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if (likely(!(desc->status & IRQ_PENDING)))
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break;
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desc->status &= ~IRQ_PENDING;
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}
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desc->status &= ~IRQ_INPROGRESS;
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out:
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/*
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* The ->end() handler has to deal with interrupts which got
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* disabled while the handler was running.
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*/
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desc->chip->end(irq);
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spin_unlock(&desc->lock);
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return 1;
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}
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#endif
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#ifdef CONFIG_TRACE_IRQFLAGS
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/*
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* lockdep: we want to handle all irq_desc locks as a single lock-class:
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*/
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static struct lock_class_key irq_desc_lock_class;
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void early_init_irq_lock_class(void)
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{
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int i;
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for (i = 0; i < NR_IRQS; i++)
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lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
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}
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#endif
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