manage.c (7acdd53e5b2c55b6f7e3427e85e2f91fa814a4f9) manage.c (009b4c3b8ad584b3462734127a5bec680d5d6af4)
1/*
2 * linux/kernel/irq/manage.c
3 *
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
6 *
7 * This file contains driver APIs to the irq subsystem.
8 */

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25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
27 *
28 * This function may be called - with care - from IRQ context.
29 */
30void synchronize_irq(unsigned int irq)
31{
32 struct irq_desc *desc = irq_to_desc(irq);
1/*
2 * linux/kernel/irq/manage.c
3 *
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006 Thomas Gleixner
6 *
7 * This file contains driver APIs to the irq subsystem.
8 */

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25 * to complete before returning. If you use this function while
26 * holding a resource the IRQ handler may need you will deadlock.
27 *
28 * This function may be called - with care - from IRQ context.
29 */
30void synchronize_irq(unsigned int irq)
31{
32 struct irq_desc *desc = irq_to_desc(irq);
33 unsigned int status;
33 unsigned int state;
34
35 if (!desc)
36 return;
37
38 do {
39 unsigned long flags;
40
41 /*
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
44 */
34
35 if (!desc)
36 return;
37
38 do {
39 unsigned long flags;
40
41 /*
42 * Wait until we're out of the critical section. This might
43 * give the wrong answer due to the lack of memory barriers.
44 */
45 while (desc->status & IRQ_INPROGRESS)
45 while (desc->istate & IRQS_INPROGRESS)
46 cpu_relax();
47
48 /* Ok, that indicated we're done: double-check carefully. */
49 raw_spin_lock_irqsave(&desc->lock, flags);
46 cpu_relax();
47
48 /* Ok, that indicated we're done: double-check carefully. */
49 raw_spin_lock_irqsave(&desc->lock, flags);
50 status = desc->status;
50 state = desc->istate;
51 raw_spin_unlock_irqrestore(&desc->lock, flags);
52
53 /* Oops, that failed? */
51 raw_spin_unlock_irqrestore(&desc->lock, flags);
52
53 /* Oops, that failed? */
54 } while (status & IRQ_INPROGRESS);
54 } while (state & IRQS_INPROGRESS);
55
56 /*
57 * We made sure that no hardirq handler is running. Now verify
58 * that no threaded handlers are active.
59 */
60 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
61}
62EXPORT_SYMBOL(synchronize_irq);

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632
633 /*
634 * Implausible though it may be we need to protect us against
635 * the following scenario:
636 *
637 * The thread is faster done than the hard interrupt handler
638 * on the other CPU. If we unmask the irq line then the
639 * interrupt can come in again and masks the line, leaves due
55
56 /*
57 * We made sure that no hardirq handler is running. Now verify
58 * that no threaded handlers are active.
59 */
60 wait_event(desc->wait_for_threads, !atomic_read(&desc->threads_active));
61}
62EXPORT_SYMBOL(synchronize_irq);

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632
633 /*
634 * Implausible though it may be we need to protect us against
635 * the following scenario:
636 *
637 * The thread is faster done than the hard interrupt handler
638 * on the other CPU. If we unmask the irq line then the
639 * interrupt can come in again and masks the line, leaves due
640 * to IRQ_INPROGRESS and the irq line is masked forever.
640 * to IRQS_INPROGRESS and the irq line is masked forever.
641 */
641 */
642 if (unlikely(desc->status & IRQ_INPROGRESS)) {
642 if (unlikely(desc->istate & IRQS_INPROGRESS)) {
643 raw_spin_unlock_irq(&desc->lock);
644 chip_bus_sync_unlock(desc);
645 cpu_relax();
646 goto again;
647 }
648
649 if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
650 desc->status &= ~IRQ_MASKED;

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892 goto out_mask;
893 } else
894 compat_irq_chip_set_default_handler(desc);
895#if defined(CONFIG_IRQ_PER_CPU)
896 if (new->flags & IRQF_PERCPU)
897 desc->status |= IRQ_PER_CPU;
898#endif
899
643 raw_spin_unlock_irq(&desc->lock);
644 chip_bus_sync_unlock(desc);
645 cpu_relax();
646 goto again;
647 }
648
649 if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
650 desc->status &= ~IRQ_MASKED;

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892 goto out_mask;
893 } else
894 compat_irq_chip_set_default_handler(desc);
895#if defined(CONFIG_IRQ_PER_CPU)
896 if (new->flags & IRQF_PERCPU)
897 desc->status |= IRQ_PER_CPU;
898#endif
899
900 desc->status &= ~(IRQ_WAITING | IRQ_ONESHOT | IRQ_INPROGRESS);
901 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED);
900 desc->status &= ~(IRQ_WAITING | IRQ_ONESHOT);
901 desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
902 IRQS_INPROGRESS);
902
903 if (new->flags & IRQF_ONESHOT)
904 desc->status |= IRQ_ONESHOT;
905
906 if (!(desc->status & IRQ_NOAUTOEN))
907 irq_startup(desc);
908 else
909 /* Undo nested disables: */

--- 378 unchanged lines hidden --- 		903
904 if (new->flags & IRQF_ONESHOT)
905 desc->status |= IRQ_ONESHOT;
906
907 if (!(desc->status & IRQ_NOAUTOEN))
908 irq_startup(desc);
909 else
910 /* Undo nested disables: */

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