arch/mips/ddb5xxx/ddb5476/vrc5476_irq.c

   1 /*
   2  * The irq controller for vrc5476.
   3  *
   4  * Copyright (C) 2001 MontaVista Software Inc.
   5  * Author: jsun@mvista.com or jsun@junsun.net
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  */
  13 #include <linux/init.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irq.h>
  16 #include <linux/types.h>
  17 #include <linux/ptrace.h>
  18
  19 #include <asm/system.h>
  20
  21 #include <asm/ddb5xxx/ddb5xxx.h>
  22
  23 static int irq_base;
  24
  25 static void vrc5476_irq_enable(uint irq)
  26 {
  27         nile4_enable_irq(irq - irq_base);
  28 }
  29
  30 static void vrc5476_irq_disable(uint irq)
  31 {
  32         nile4_disable_irq(irq - irq_base);
  33 }
  34
  35 static unsigned int vrc5476_irq_startup(uint irq)
  36 {
  37         nile4_enable_irq(irq - irq_base);
  38         return 0;
  39 }
  40
  41 #define vrc5476_irq_shutdown    vrc5476_irq_disable
  42
  43 static void vrc5476_irq_ack(uint irq)
  44 {
  45         nile4_clear_irq(irq - irq_base);
  46         nile4_disable_irq(irq - irq_base);
  47 }
  48
  49 static void vrc5476_irq_end(uint irq)
  50 {
  51         if(!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS)))
  52                 vrc5476_irq_enable(irq);
  53 }
  54
  55 static hw_irq_controller vrc5476_irq_controller = {
  56         "vrc5476",
  57         vrc5476_irq_startup,
  58         vrc5476_irq_shutdown,
  59         vrc5476_irq_enable,
  60         vrc5476_irq_disable,
  61         vrc5476_irq_ack,
  62         vrc5476_irq_end,
  63         NULL                            /* no affinity stuff for UP */
  64 };
  65
  66 void __init
  67 vrc5476_irq_init(u32 base)
  68 {
  69         extern irq_desc_t irq_desc[];
  70         u32 i;
  71
  72         irq_base = base;
  73         for (i= base; i< base + NUM_VRC5476_IRQ; i++) {
  74                 irq_desc[i].status = IRQ_DISABLED;
  75                 irq_desc[i].action = NULL;
  76                  irq_desc[i].depth = 1;
  77                  irq_desc[i].handler = &vrc5476_irq_controller;
  78         }
  79 }
  80
  81
  82 asmlinkage void
  83 vrc5476_irq_dispatch(struct pt_regs *regs)
  84 {
  85         extern void spurious_interrupt(void);
  86
  87         u32 mask;
  88         int nile4_irq;
  89
  90         mask = nile4_get_irq_stat(0);
  91
  92         /* quick check for possible time interrupt */
  93         if (mask & (1 << VRC5476_IRQ_GPT)) {
  94                 do_IRQ(VRC5476_IRQ_BASE + VRC5476_IRQ_GPT, regs);
  95                 return;
  96         }
  97
  98         /* check for i8259 interrupts */
  99         if (mask & (1 << VRC5476_I8259_CASCADE)) {
 100                 int i8259_irq = nile4_i8259_iack();
 101                 do_IRQ(I8259_IRQ_BASE + i8259_irq, regs);
 102                 return;
 103         }
 104
 105         /* regular nile4 interrupts (we should not really have any */
 106         for (nile4_irq = 0; mask; nile4_irq++, mask >>= 1) {
 107                 if (mask & 1) {
 108                         do_IRQ(VRC5476_IRQ_BASE + nile4_irq, regs);
 109                         return;
 110                 }
 111         }
 112         spurious_interrupt();
 113 }