release/src-rt-6.x.4708/linux/linux-2.6.36/kernel/irq/resend.c

   1 /* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */
   2 /*
   3  * linux/kernel/irq/resend.c
   4  *
   5  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   6  * Copyright (C) 2005-2006, Thomas Gleixner
   7  *
   8  * This file contains the IRQ-resend code
   9  *
  10  * If the interrupt is waiting to be processed, we try to re-run it.
  11  * We can't directly run it from here since the caller might be in an
  12  * interrupt-protected region. Not all irq controller chips can
  13  * retrigger interrupts at the hardware level, so in those cases
  14  * we allow the resending of IRQs via a tasklet.
  15  */
  16
  17 #include <linux/irq.h>
  18 #include <linux/module.h>
  19 #include <linux/random.h>
  20 #include <linux/interrupt.h>
  21
  22 #if defined(CONFIG_BUZZZ)
  23 #include <asm/buzzz.h>
  24 #endif  /*  CONFIG_BUZZZ */
  25
  26 #include "internals.h"
  27
  28 #ifdef CONFIG_HARDIRQS_SW_RESEND
  29
  30 /* Bitmap to handle software resend of interrupts: */
  31 static DECLARE_BITMAP(irqs_resend, NR_IRQS);
  32
  33 /*
  34  * Run software resends of IRQ's
  35  */
  36 static void resend_irqs(unsigned long arg)
  37 {
  38         struct irq_desc *desc;
  39         int irq;
  40
  41         while (!bitmap_empty(irqs_resend, nr_irqs)) {
  42                 irq = find_first_bit(irqs_resend, nr_irqs);
  43
  44 #if defined(BUZZZ_KEVT_LVL) && (BUZZZ_KEVT_LVL >= 1)
  45                 buzzz_kevt_log1(BUZZZ_KEVT_ID_IRQ_RESEND, irq);
  46 #endif  /* BUZZZ_KEVT_LVL */
  47
  48                 clear_bit(irq, irqs_resend);
  49                 desc = irq_to_desc(irq);
  50                 local_irq_disable();
  51                 desc->handle_irq(irq, desc);
  52                 local_irq_enable();
  53         }
  54 }
  55
  56 /* Tasklet to handle resend: */
  57 static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
  58
  59 #endif
  60
  61 /*
  62  * IRQ resend
  63  *
  64  * Is called with interrupts disabled and desc->lock held.
  65  */
  66 void check_irq_resend(struct irq_desc *desc, unsigned int irq)
  67 {
  68         unsigned int status = desc->status;
  69
  70 #if defined(BUZZZ_KEVT_LVL) && (BUZZZ_KEVT_LVL >= 1)
  71         buzzz_kevt_log1(BUZZZ_KEVT_ID_IRQ_CHECK, irq);
  72 #endif  /* BUZZZ_KEVT_LVL */
  73
  74         /*
  75          * Make sure the interrupt is enabled, before resending it:
  76          */
  77         desc->chip->enable(irq);
  78
  79         /*
  80          * We do not resend level type interrupts. Level type
  81          * interrupts are resent by hardware when they are still
  82          * active.
  83          */
  84         if ((status & (IRQ_LEVEL | IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
  85                 desc->status = (status & ~IRQ_PENDING) | IRQ_REPLAY;
  86
  87                 if (!desc->chip->retrigger || !desc->chip->retrigger(irq)) {
  88 #ifdef CONFIG_HARDIRQS_SW_RESEND
  89                         /* Set it pending and activate the softirq: */
  90                         set_bit(irq, irqs_resend);
  91                         tasklet_schedule(&resend_tasklet);
  92 #endif
  93                 }
  94         }
  95 }