| 1 | /* |
| 2 | * linux/kernel/irq/resend.c |
| 3 | * |
| 4 | * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
| 5 | * Copyright (C) 2005-2006, Thomas Gleixner |
| 6 | * |
| 7 | * This file contains the IRQ-resend code |
| 8 | * |
| 9 | * If the interrupt is waiting to be processed, we try to re-run it. |
| 10 | * We can't directly run it from here since the caller might be in an |
| 11 | * interrupt-protected region. Not all irq controller chips can |
| 12 | * retrigger interrupts at the hardware level, so in those cases |
| 13 | * we allow the resending of IRQs via a tasklet. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/irq.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/random.h> |
| 19 | #include <linux/interrupt.h> |
| 20 | |
| 21 | #include "internals.h" |
| 22 | |
| 23 | #ifdef CONFIG_HARDIRQS_SW_RESEND |
| 24 | |
| 25 | /* Bitmap to handle software resend of interrupts: */ |
| 26 | static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS); |
| 27 | |
| 28 | /* |
| 29 | * Run software resends of IRQ's |
| 30 | */ |
| 31 | static void resend_irqs(unsigned long arg) |
| 32 | { |
| 33 | struct irq_desc *desc; |
| 34 | int irq; |
| 35 | |
| 36 | while (!bitmap_empty(irqs_resend, nr_irqs)) { |
| 37 | irq = find_first_bit(irqs_resend, nr_irqs); |
| 38 | clear_bit(irq, irqs_resend); |
| 39 | desc = irq_to_desc(irq); |
| 40 | local_irq_disable(); |
| 41 | desc->handle_irq(desc); |
| 42 | local_irq_enable(); |
| 43 | } |
| 44 | } |
| 45 | |
| 46 | /* Tasklet to handle resend: */ |
| 47 | static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0); |
| 48 | |
| 49 | #endif |
| 50 | |
| 51 | /* |
| 52 | * IRQ resend |
| 53 | * |
| 54 | * Is called with interrupts disabled and desc->lock held. |
| 55 | */ |
| 56 | void check_irq_resend(struct irq_desc *desc) |
| 57 | { |
| 58 | /* |
| 59 | * We do not resend level type interrupts. Level type |
| 60 | * interrupts are resent by hardware when they are still |
| 61 | * active. Clear the pending bit so suspend/resume does not |
| 62 | * get confused. |
| 63 | */ |
| 64 | if (irq_settings_is_level(desc)) { |
| 65 | desc->istate &= ~IRQS_PENDING; |
| 66 | return; |
| 67 | } |
| 68 | if (desc->istate & IRQS_REPLAY) |
| 69 | return; |
| 70 | if (desc->istate & IRQS_PENDING) { |
| 71 | desc->istate &= ~IRQS_PENDING; |
| 72 | desc->istate |= IRQS_REPLAY; |
| 73 | |
| 74 | if (!desc->irq_data.chip->irq_retrigger || |
| 75 | !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) { |
| 76 | #ifdef CONFIG_HARDIRQS_SW_RESEND |
| 77 | unsigned int irq = irq_desc_get_irq(desc); |
| 78 | |
| 79 | /* |
| 80 | * If the interrupt is running in the thread |
| 81 | * context of the parent irq we need to be |
| 82 | * careful, because we cannot trigger it |
| 83 | * directly. |
| 84 | */ |
| 85 | if (irq_settings_is_nested_thread(desc)) { |
| 86 | /* |
| 87 | * If the parent_irq is valid, we |
| 88 | * retrigger the parent, otherwise we |
| 89 | * do nothing. |
| 90 | */ |
| 91 | if (!desc->parent_irq) |
| 92 | return; |
| 93 | irq = desc->parent_irq; |
| 94 | } |
| 95 | /* Set it pending and activate the softirq: */ |
| 96 | set_bit(irq, irqs_resend); |
| 97 | tasklet_schedule(&resend_tasklet); |
| 98 | #endif |
| 99 | } |
| 100 | } |
| 101 | } |