954 lines
23 KiB
C
954 lines
23 KiB
C
/*
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* linux/kernel/irq/manage.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
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*
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* This file contains driver APIs to the irq subsystem.
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*/
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#include <linux/irq.h>
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#include <linux/kthread.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/slab.h>
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#include <linux/sched.h>
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#include "internals.h"
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/**
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* synchronize_irq - wait for pending IRQ handlers (on other CPUs)
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* @irq: interrupt number to wait for
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*
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* This function waits for any pending IRQ handlers for this interrupt
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* to complete before returning. If you use this function while
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* holding a resource the IRQ handler may need you will deadlock.
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*
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* This function may be called - with care - from IRQ context.
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*/
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void synchronize_irq(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned int status;
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if (!desc)
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return;
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do {
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unsigned long flags;
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/*
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* Wait until we're out of the critical section. This might
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* give the wrong answer due to the lack of memory barriers.
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*/
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while (desc->status & IRQ_INPROGRESS)
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cpu_relax();
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/* Ok, that indicated we're done: double-check carefully. */
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spin_lock_irqsave(&desc->lock, flags);
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status = desc->status;
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spin_unlock_irqrestore(&desc->lock, flags);
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/* Oops, that failed? */
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} while (status & IRQ_INPROGRESS);
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/*
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* We made sure that no hardirq handler is running. Now verify
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* that no threaded handlers are active.
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*/
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wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
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}
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EXPORT_SYMBOL(synchronize_irq);
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#ifdef CONFIG_SMP
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cpumask_var_t irq_default_affinity;
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/**
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* irq_can_set_affinity - Check if the affinity of a given irq can be set
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* @irq: Interrupt to check
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*
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*/
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int irq_can_set_affinity(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (CHECK_IRQ_PER_CPU(desc->status) || !desc->chip ||
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!desc->chip->set_affinity)
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return 0;
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return 1;
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}
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static void
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irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask)
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{
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struct irqaction *action = desc->action;
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while (action) {
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if (action->thread)
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set_cpus_allowed_ptr(action->thread, cpumask);
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action = action->next;
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}
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}
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/**
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* irq_set_affinity - Set the irq affinity of a given irq
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* @irq: Interrupt to set affinity
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* @cpumask: cpumask
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*
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*/
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int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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if (!desc->chip->set_affinity)
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return -EINVAL;
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spin_lock_irqsave(&desc->lock, flags);
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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if (desc->status & IRQ_MOVE_PCNTXT)
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desc->chip->set_affinity(irq, cpumask);
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else {
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desc->status |= IRQ_MOVE_PENDING;
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cpumask_copy(desc->pending_mask, cpumask);
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}
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#else
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cpumask_copy(desc->affinity, cpumask);
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desc->chip->set_affinity(irq, cpumask);
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#endif
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irq_set_thread_affinity(desc, cpumask);
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desc->status |= IRQ_AFFINITY_SET;
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spin_unlock_irqrestore(&desc->lock, flags);
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return 0;
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}
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#ifndef CONFIG_AUTO_IRQ_AFFINITY
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/*
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* Generic version of the affinity autoselector.
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*/
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static int setup_affinity(unsigned int irq, struct irq_desc *desc)
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{
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if (!irq_can_set_affinity(irq))
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return 0;
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/*
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* Preserve an userspace affinity setup, but make sure that
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* one of the targets is online.
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*/
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if (desc->status & (IRQ_AFFINITY_SET | IRQ_NO_BALANCING)) {
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if (cpumask_any_and(desc->affinity, cpu_online_mask)
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< nr_cpu_ids)
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goto set_affinity;
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else
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desc->status &= ~IRQ_AFFINITY_SET;
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}
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cpumask_and(desc->affinity, cpu_online_mask, irq_default_affinity);
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set_affinity:
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desc->chip->set_affinity(irq, desc->affinity);
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return 0;
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}
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#else
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static inline int setup_affinity(unsigned int irq, struct irq_desc *d)
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{
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return irq_select_affinity(irq);
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}
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#endif
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/*
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* Called when affinity is set via /proc/irq
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*/
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int irq_select_affinity_usr(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&desc->lock, flags);
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ret = setup_affinity(irq, desc);
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if (!ret)
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irq_set_thread_affinity(desc, desc->affinity);
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spin_unlock_irqrestore(&desc->lock, flags);
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return ret;
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}
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#else
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static inline int setup_affinity(unsigned int irq, struct irq_desc *desc)
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{
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return 0;
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}
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#endif
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void __disable_irq(struct irq_desc *desc, unsigned int irq, bool suspend)
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{
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if (suspend) {
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if (!desc->action || (desc->action->flags & IRQF_TIMER))
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return;
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desc->status |= IRQ_SUSPENDED;
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}
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if (!desc->depth++) {
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desc->status |= IRQ_DISABLED;
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desc->chip->disable(irq);
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}
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}
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/**
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* disable_irq_nosync - disable an irq without waiting
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* @irq: Interrupt to disable
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*
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* Disable the selected interrupt line. Disables and Enables are
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* nested.
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* Unlike disable_irq(), this function does not ensure existing
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* instances of the IRQ handler have completed before returning.
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*
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* This function may be called from IRQ context.
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*/
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void disable_irq_nosync(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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if (!desc)
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return;
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spin_lock_irqsave(&desc->lock, flags);
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__disable_irq(desc, irq, false);
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spin_unlock_irqrestore(&desc->lock, flags);
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}
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EXPORT_SYMBOL(disable_irq_nosync);
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/**
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* disable_irq - disable an irq and wait for completion
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* @irq: Interrupt to disable
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*
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* Disable the selected interrupt line. Enables and Disables are
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* nested.
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* This function waits for any pending IRQ handlers for this interrupt
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* to complete before returning. If you use this function while
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* holding a resource the IRQ handler may need you will deadlock.
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*
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* This function may be called - with care - from IRQ context.
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*/
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void disable_irq(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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if (!desc)
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return;
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disable_irq_nosync(irq);
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if (desc->action)
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synchronize_irq(irq);
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}
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EXPORT_SYMBOL(disable_irq);
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void __enable_irq(struct irq_desc *desc, unsigned int irq, bool resume)
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{
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if (resume)
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desc->status &= ~IRQ_SUSPENDED;
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switch (desc->depth) {
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case 0:
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err_out:
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WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
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break;
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case 1: {
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unsigned int status = desc->status & ~IRQ_DISABLED;
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if (desc->status & IRQ_SUSPENDED)
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goto err_out;
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/* Prevent probing on this irq: */
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desc->status = status | IRQ_NOPROBE;
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check_irq_resend(desc, irq);
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/* fall-through */
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}
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default:
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desc->depth--;
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}
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}
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/**
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* enable_irq - enable handling of an irq
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* @irq: Interrupt to enable
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*
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* Undoes the effect of one call to disable_irq(). If this
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* matches the last disable, processing of interrupts on this
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* IRQ line is re-enabled.
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*
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* This function may be called from IRQ context.
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*/
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void enable_irq(unsigned int irq)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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if (!desc)
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return;
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spin_lock_irqsave(&desc->lock, flags);
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__enable_irq(desc, irq, false);
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spin_unlock_irqrestore(&desc->lock, flags);
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}
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EXPORT_SYMBOL(enable_irq);
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static int set_irq_wake_real(unsigned int irq, unsigned int on)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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int ret = -ENXIO;
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if (desc->chip->set_wake)
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ret = desc->chip->set_wake(irq, on);
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return ret;
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}
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/**
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* set_irq_wake - control irq power management wakeup
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* @irq: interrupt to control
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* @on: enable/disable power management wakeup
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*
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* Enable/disable power management wakeup mode, which is
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* disabled by default. Enables and disables must match,
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* just as they match for non-wakeup mode support.
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*
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* Wakeup mode lets this IRQ wake the system from sleep
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* states like "suspend to RAM".
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*/
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int set_irq_wake(unsigned int irq, unsigned int on)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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unsigned long flags;
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int ret = 0;
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/* wakeup-capable irqs can be shared between drivers that
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* don't need to have the same sleep mode behaviors.
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*/
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spin_lock_irqsave(&desc->lock, flags);
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if (on) {
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if (desc->wake_depth++ == 0) {
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ret = set_irq_wake_real(irq, on);
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if (ret)
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desc->wake_depth = 0;
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else
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desc->status |= IRQ_WAKEUP;
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}
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} else {
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if (desc->wake_depth == 0) {
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WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
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} else if (--desc->wake_depth == 0) {
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ret = set_irq_wake_real(irq, on);
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if (ret)
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desc->wake_depth = 1;
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else
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desc->status &= ~IRQ_WAKEUP;
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}
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}
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spin_unlock_irqrestore(&desc->lock, flags);
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return ret;
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}
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EXPORT_SYMBOL(set_irq_wake);
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/*
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* Internal function that tells the architecture code whether a
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* particular irq has been exclusively allocated or is available
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* for driver use.
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*/
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int can_request_irq(unsigned int irq, unsigned long irqflags)
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{
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struct irq_desc *desc = irq_to_desc(irq);
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struct irqaction *action;
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if (!desc)
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return 0;
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if (desc->status & IRQ_NOREQUEST)
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return 0;
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action = desc->action;
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if (action)
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if (irqflags & action->flags & IRQF_SHARED)
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action = NULL;
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return !action;
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}
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void compat_irq_chip_set_default_handler(struct irq_desc *desc)
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{
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/*
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* If the architecture still has not overriden
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* the flow handler then zap the default. This
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* should catch incorrect flow-type setting.
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*/
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if (desc->handle_irq == &handle_bad_irq)
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desc->handle_irq = NULL;
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}
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int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
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unsigned long flags)
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{
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int ret;
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struct irq_chip *chip = desc->chip;
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if (!chip || !chip->set_type) {
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/*
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* IRQF_TRIGGER_* but the PIC does not support multiple
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* flow-types?
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*/
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pr_debug("No set_type function for IRQ %d (%s)\n", irq,
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chip ? (chip->name ? : "unknown") : "unknown");
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return 0;
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}
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/* caller masked out all except trigger mode flags */
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ret = chip->set_type(irq, flags);
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if (ret)
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pr_err("setting trigger mode %d for irq %u failed (%pF)\n",
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(int)flags, irq, chip->set_type);
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else {
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if (flags & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
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flags |= IRQ_LEVEL;
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/* note that IRQF_TRIGGER_MASK == IRQ_TYPE_SENSE_MASK */
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desc->status &= ~(IRQ_LEVEL | IRQ_TYPE_SENSE_MASK);
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desc->status |= flags;
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}
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return ret;
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}
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static int irq_wait_for_interrupt(struct irqaction *action)
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{
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while (!kthread_should_stop()) {
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set_current_state(TASK_INTERRUPTIBLE);
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if (test_and_clear_bit(IRQTF_RUNTHREAD,
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&action->thread_flags)) {
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__set_current_state(TASK_RUNNING);
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return 0;
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}
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schedule();
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}
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return -1;
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}
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/*
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* Interrupt handler thread
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*/
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static int irq_thread(void *data)
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{
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struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2, };
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struct irqaction *action = data;
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struct irq_desc *desc = irq_to_desc(action->irq);
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int wake;
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sched_setscheduler(current, SCHED_FIFO, ¶m);
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current->irqaction = action;
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while (!irq_wait_for_interrupt(action)) {
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atomic_inc(&desc->threads_active);
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spin_lock_irq(&desc->lock);
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if (unlikely(desc->status & IRQ_DISABLED)) {
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/*
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* CHECKME: We might need a dedicated
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* IRQ_THREAD_PENDING flag here, which
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* retriggers the thread in check_irq_resend()
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* but AFAICT IRQ_PENDING should be fine as it
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* retriggers the interrupt itself --- tglx
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*/
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desc->status |= IRQ_PENDING;
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spin_unlock_irq(&desc->lock);
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} else {
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spin_unlock_irq(&desc->lock);
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action->thread_fn(action->irq, action->dev_id);
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}
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wake = atomic_dec_and_test(&desc->threads_active);
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if (wake && waitqueue_active(&desc->wait_for_threads))
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wake_up(&desc->wait_for_threads);
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}
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/*
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* Clear irqaction. Otherwise exit_irq_thread() would make
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* fuzz about an active irq thread going into nirvana.
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*/
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current->irqaction = NULL;
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return 0;
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}
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/*
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* Called from do_exit()
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*/
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void exit_irq_thread(void)
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{
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struct task_struct *tsk = current;
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if (!tsk->irqaction)
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return;
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printk(KERN_ERR
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"exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
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tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
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/*
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* Set the THREAD DIED flag to prevent further wakeups of the
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* soon to be gone threaded handler.
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*/
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set_bit(IRQTF_DIED, &tsk->irqaction->flags);
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}
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/*
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* Internal function to register an irqaction - typically used to
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* allocate special interrupts that are part of the architecture.
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*/
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static int
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__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
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{
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struct irqaction *old, **old_ptr;
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const char *old_name = NULL;
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unsigned long flags;
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int shared = 0;
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int ret;
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if (!desc)
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return -EINVAL;
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if (desc->chip == &no_irq_chip)
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return -ENOSYS;
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/*
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* Some drivers like serial.c use request_irq() heavily,
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* so we have to be careful not to interfere with a
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* running system.
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*/
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if (new->flags & IRQF_SAMPLE_RANDOM) {
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/*
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* This function might sleep, we want to call it first,
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* outside of the atomic block.
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* Yes, this might clear the entropy pool if the wrong
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* driver is attempted to be loaded, without actually
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* installing a new handler, but is this really a problem,
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* only the sysadmin is able to do this.
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*/
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rand_initialize_irq(irq);
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}
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/*
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* Threaded handler ?
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*/
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if (new->thread_fn) {
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struct task_struct *t;
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t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
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new->name);
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if (IS_ERR(t))
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return PTR_ERR(t);
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/*
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* We keep the reference to the task struct even if
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* the thread dies to avoid that the interrupt code
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* references an already freed task_struct.
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*/
|
|
get_task_struct(t);
|
|
new->thread = t;
|
|
wake_up_process(t);
|
|
}
|
|
|
|
/*
|
|
* The following block of code has to be executed atomically
|
|
*/
|
|
spin_lock_irqsave(&desc->lock, flags);
|
|
old_ptr = &desc->action;
|
|
old = *old_ptr;
|
|
if (old) {
|
|
/*
|
|
* Can't share interrupts unless both agree to and are
|
|
* the same type (level, edge, polarity). So both flag
|
|
* fields must have IRQF_SHARED set and the bits which
|
|
* set the trigger type must match.
|
|
*/
|
|
if (!((old->flags & new->flags) & IRQF_SHARED) ||
|
|
((old->flags ^ new->flags) & IRQF_TRIGGER_MASK)) {
|
|
old_name = old->name;
|
|
goto mismatch;
|
|
}
|
|
|
|
#if defined(CONFIG_IRQ_PER_CPU)
|
|
/* All handlers must agree on per-cpuness */
|
|
if ((old->flags & IRQF_PERCPU) !=
|
|
(new->flags & IRQF_PERCPU))
|
|
goto mismatch;
|
|
#endif
|
|
|
|
/* add new interrupt at end of irq queue */
|
|
do {
|
|
old_ptr = &old->next;
|
|
old = *old_ptr;
|
|
} while (old);
|
|
shared = 1;
|
|
}
|
|
|
|
if (!shared) {
|
|
irq_chip_set_defaults(desc->chip);
|
|
|
|
init_waitqueue_head(&desc->wait_for_threads);
|
|
|
|
/* Setup the type (level, edge polarity) if configured: */
|
|
if (new->flags & IRQF_TRIGGER_MASK) {
|
|
ret = __irq_set_trigger(desc, irq,
|
|
new->flags & IRQF_TRIGGER_MASK);
|
|
|
|
if (ret)
|
|
goto out_thread;
|
|
} else
|
|
compat_irq_chip_set_default_handler(desc);
|
|
#if defined(CONFIG_IRQ_PER_CPU)
|
|
if (new->flags & IRQF_PERCPU)
|
|
desc->status |= IRQ_PER_CPU;
|
|
#endif
|
|
|
|
desc->status &= ~(IRQ_AUTODETECT | IRQ_WAITING |
|
|
IRQ_INPROGRESS | IRQ_SPURIOUS_DISABLED);
|
|
|
|
if (!(desc->status & IRQ_NOAUTOEN)) {
|
|
desc->depth = 0;
|
|
desc->status &= ~IRQ_DISABLED;
|
|
desc->chip->startup(irq);
|
|
} else
|
|
/* Undo nested disables: */
|
|
desc->depth = 1;
|
|
|
|
/* Exclude IRQ from balancing if requested */
|
|
if (new->flags & IRQF_NOBALANCING)
|
|
desc->status |= IRQ_NO_BALANCING;
|
|
|
|
/* Set default affinity mask once everything is setup */
|
|
setup_affinity(irq, desc);
|
|
|
|
} else if ((new->flags & IRQF_TRIGGER_MASK)
|
|
&& (new->flags & IRQF_TRIGGER_MASK)
|
|
!= (desc->status & IRQ_TYPE_SENSE_MASK)) {
|
|
/* hope the handler works with the actual trigger mode... */
|
|
pr_warning("IRQ %d uses trigger mode %d; requested %d\n",
|
|
irq, (int)(desc->status & IRQ_TYPE_SENSE_MASK),
|
|
(int)(new->flags & IRQF_TRIGGER_MASK));
|
|
}
|
|
|
|
*old_ptr = new;
|
|
|
|
/* Reset broken irq detection when installing new handler */
|
|
desc->irq_count = 0;
|
|
desc->irqs_unhandled = 0;
|
|
|
|
/*
|
|
* Check whether we disabled the irq via the spurious handler
|
|
* before. Reenable it and give it another chance.
|
|
*/
|
|
if (shared && (desc->status & IRQ_SPURIOUS_DISABLED)) {
|
|
desc->status &= ~IRQ_SPURIOUS_DISABLED;
|
|
__enable_irq(desc, irq, false);
|
|
}
|
|
|
|
spin_unlock_irqrestore(&desc->lock, flags);
|
|
|
|
new->irq = irq;
|
|
register_irq_proc(irq, desc);
|
|
new->dir = NULL;
|
|
register_handler_proc(irq, new);
|
|
|
|
return 0;
|
|
|
|
mismatch:
|
|
#ifdef CONFIG_DEBUG_SHIRQ
|
|
if (!(new->flags & IRQF_PROBE_SHARED)) {
|
|
printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
|
|
if (old_name)
|
|
printk(KERN_ERR "current handler: %s\n", old_name);
|
|
dump_stack();
|
|
}
|
|
#endif
|
|
ret = -EBUSY;
|
|
|
|
out_thread:
|
|
spin_unlock_irqrestore(&desc->lock, flags);
|
|
if (new->thread) {
|
|
struct task_struct *t = new->thread;
|
|
|
|
new->thread = NULL;
|
|
if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
|
|
kthread_stop(t);
|
|
put_task_struct(t);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* setup_irq - setup an interrupt
|
|
* @irq: Interrupt line to setup
|
|
* @act: irqaction for the interrupt
|
|
*
|
|
* Used to statically setup interrupts in the early boot process.
|
|
*/
|
|
int setup_irq(unsigned int irq, struct irqaction *act)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
|
|
return __setup_irq(irq, desc, act);
|
|
}
|
|
EXPORT_SYMBOL_GPL(setup_irq);
|
|
|
|
/*
|
|
* Internal function to unregister an irqaction - used to free
|
|
* regular and special interrupts that are part of the architecture.
|
|
*/
|
|
static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
|
|
{
|
|
struct irq_desc *desc = irq_to_desc(irq);
|
|
struct irqaction *action, **action_ptr;
|
|
struct task_struct *irqthread;
|
|
unsigned long flags;
|
|
|
|
WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
|
|
|
|
if (!desc)
|
|
return NULL;
|
|
|
|
spin_lock_irqsave(&desc->lock, flags);
|
|
|
|
/*
|
|
* There can be multiple actions per IRQ descriptor, find the right
|
|
* one based on the dev_id:
|
|
*/
|
|
action_ptr = &desc->action;
|
|
for (;;) {
|
|
action = *action_ptr;
|
|
|
|
if (!action) {
|
|
WARN(1, "Trying to free already-free IRQ %d\n", irq);
|
|
spin_unlock_irqrestore(&desc->lock, flags);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
if (action->dev_id == dev_id)
|
|
break;
|
|
action_ptr = &action->next;
|
|
}
|
|
|
|
/* Found it - now remove it from the list of entries: */
|
|
*action_ptr = action->next;
|
|
|
|
/* Currently used only by UML, might disappear one day: */
|
|
#ifdef CONFIG_IRQ_RELEASE_METHOD
|
|
if (desc->chip->release)
|
|
desc->chip->release(irq, dev_id);
|
|
#endif
|
|
|
|
/* If this was the last handler, shut down the IRQ line: */
|
|
if (!desc->action) {
|
|
desc->status |= IRQ_DISABLED;
|
|
if (desc->chip->shutdown)
|
|
desc->chip->shutdown(irq);
|
|
else
|
|
desc->chip->disable(irq);
|
|
}
|
|
|
|
irqthread = action->thread;
|
|
action->thread = NULL;
|
|
|
|
spin_unlock_irqrestore(&desc->lock, flags);
|
|
|
|
unregister_handler_proc(irq, action);
|
|
|
|
/* Make sure it's not being used on another CPU: */
|
|
synchronize_irq(irq);
|
|
|
|
if (irqthread) {
|
|
if (!test_bit(IRQTF_DIED, &action->thread_flags))
|
|
kthread_stop(irqthread);
|
|
put_task_struct(irqthread);
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_SHIRQ
|
|
/*
|
|
* It's a shared IRQ -- the driver ought to be prepared for an IRQ
|
|
* event to happen even now it's being freed, so let's make sure that
|
|
* is so by doing an extra call to the handler ....
|
|
*
|
|
* ( We do this after actually deregistering it, to make sure that a
|
|
* 'real' IRQ doesn't run in * parallel with our fake. )
|
|
*/
|
|
if (action->flags & IRQF_SHARED) {
|
|
local_irq_save(flags);
|
|
action->handler(irq, dev_id);
|
|
local_irq_restore(flags);
|
|
}
|
|
#endif
|
|
return action;
|
|
}
|
|
|
|
/**
|
|
* remove_irq - free an interrupt
|
|
* @irq: Interrupt line to free
|
|
* @act: irqaction for the interrupt
|
|
*
|
|
* Used to remove interrupts statically setup by the early boot process.
|
|
*/
|
|
void remove_irq(unsigned int irq, struct irqaction *act)
|
|
{
|
|
__free_irq(irq, act->dev_id);
|
|
}
|
|
EXPORT_SYMBOL_GPL(remove_irq);
|
|
|
|
/**
|
|
* free_irq - free an interrupt allocated with request_irq
|
|
* @irq: Interrupt line to free
|
|
* @dev_id: Device identity to free
|
|
*
|
|
* Remove an interrupt handler. The handler is removed and if the
|
|
* interrupt line is no longer in use by any driver it is disabled.
|
|
* On a shared IRQ the caller must ensure the interrupt is disabled
|
|
* on the card it drives before calling this function. The function
|
|
* does not return until any executing interrupts for this IRQ
|
|
* have completed.
|
|
*
|
|
* This function must not be called from interrupt context.
|
|
*/
|
|
void free_irq(unsigned int irq, void *dev_id)
|
|
{
|
|
kfree(__free_irq(irq, dev_id));
|
|
}
|
|
EXPORT_SYMBOL(free_irq);
|
|
|
|
/**
|
|
* request_threaded_irq - allocate an interrupt line
|
|
* @irq: Interrupt line to allocate
|
|
* @handler: Function to be called when the IRQ occurs.
|
|
* Primary handler for threaded interrupts
|
|
* @thread_fn: Function called from the irq handler thread
|
|
* If NULL, no irq thread is created
|
|
* @irqflags: Interrupt type flags
|
|
* @devname: An ascii name for the claiming device
|
|
* @dev_id: A cookie passed back to the handler function
|
|
*
|
|
* This call allocates interrupt resources and enables the
|
|
* interrupt line and IRQ handling. From the point this
|
|
* call is made your handler function may be invoked. Since
|
|
* your handler function must clear any interrupt the board
|
|
* raises, you must take care both to initialise your hardware
|
|
* and to set up the interrupt handler in the right order.
|
|
*
|
|
* If you want to set up a threaded irq handler for your device
|
|
* then you need to supply @handler and @thread_fn. @handler ist
|
|
* still called in hard interrupt context and has to check
|
|
* whether the interrupt originates from the device. If yes it
|
|
* needs to disable the interrupt on the device and return
|
|
* IRQ_THREAD_WAKE which will wake up the handler thread and run
|
|
* @thread_fn. This split handler design is necessary to support
|
|
* shared interrupts.
|
|
*
|
|
* Dev_id must be globally unique. Normally the address of the
|
|
* device data structure is used as the cookie. Since the handler
|
|
* receives this value it makes sense to use it.
|
|
*
|
|
* If your interrupt is shared you must pass a non NULL dev_id
|
|
* as this is required when freeing the interrupt.
|
|
*
|
|
* Flags:
|
|
*
|
|
* IRQF_SHARED Interrupt is shared
|
|
* IRQF_DISABLED Disable local interrupts while processing
|
|
* IRQF_SAMPLE_RANDOM The interrupt can be used for entropy
|
|
* IRQF_TRIGGER_* Specify active edge(s) or level
|
|
*
|
|
*/
|
|
int request_threaded_irq(unsigned int irq, irq_handler_t handler,
|
|
irq_handler_t thread_fn, unsigned long irqflags,
|
|
const char *devname, void *dev_id)
|
|
{
|
|
struct irqaction *action;
|
|
struct irq_desc *desc;
|
|
int retval;
|
|
|
|
/*
|
|
* handle_IRQ_event() always ignores IRQF_DISABLED except for
|
|
* the _first_ irqaction (sigh). That can cause oopsing, but
|
|
* the behavior is classified as "will not fix" so we need to
|
|
* start nudging drivers away from using that idiom.
|
|
*/
|
|
if ((irqflags & (IRQF_SHARED|IRQF_DISABLED)) ==
|
|
(IRQF_SHARED|IRQF_DISABLED)) {
|
|
pr_warning(
|
|
"IRQ %d/%s: IRQF_DISABLED is not guaranteed on shared IRQs\n",
|
|
irq, devname);
|
|
}
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
/*
|
|
* Lockdep wants atomic interrupt handlers:
|
|
*/
|
|
irqflags |= IRQF_DISABLED;
|
|
#endif
|
|
/*
|
|
* Sanity-check: shared interrupts must pass in a real dev-ID,
|
|
* otherwise we'll have trouble later trying to figure out
|
|
* which interrupt is which (messes up the interrupt freeing
|
|
* logic etc).
|
|
*/
|
|
if ((irqflags & IRQF_SHARED) && !dev_id)
|
|
return -EINVAL;
|
|
|
|
desc = irq_to_desc(irq);
|
|
if (!desc)
|
|
return -EINVAL;
|
|
|
|
if (desc->status & IRQ_NOREQUEST)
|
|
return -EINVAL;
|
|
if (!handler)
|
|
return -EINVAL;
|
|
|
|
action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
|
|
if (!action)
|
|
return -ENOMEM;
|
|
|
|
action->handler = handler;
|
|
action->thread_fn = thread_fn;
|
|
action->flags = irqflags;
|
|
action->name = devname;
|
|
action->dev_id = dev_id;
|
|
|
|
retval = __setup_irq(irq, desc, action);
|
|
if (retval)
|
|
kfree(action);
|
|
|
|
#ifdef CONFIG_DEBUG_SHIRQ
|
|
if (irqflags & IRQF_SHARED) {
|
|
/*
|
|
* It's a shared IRQ -- the driver ought to be prepared for it
|
|
* to happen immediately, so let's make sure....
|
|
* We disable the irq to make sure that a 'real' IRQ doesn't
|
|
* run in parallel with our fake.
|
|
*/
|
|
unsigned long flags;
|
|
|
|
disable_irq(irq);
|
|
local_irq_save(flags);
|
|
|
|
handler(irq, dev_id);
|
|
|
|
local_irq_restore(flags);
|
|
enable_irq(irq);
|
|
}
|
|
#endif
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL(request_threaded_irq);
|