arch/mips/vr41xx/common/irq.c

   1 /*
   2  *  Interrupt handing routines for NEC VR4100 series.
   3  *
   4  *  Copyright (C) 2005-2007  Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <linux/interrupt.h>
  21 #include <linux/module.h>
  22
  23 #include <asm/irq_cpu.h>
  24 #include <asm/system.h>
  25 #include <asm/vr41xx/irq.h>
  26
  27 typedef struct irq_cascade {
  28         int (*get_irq)(unsigned int);
  29 } irq_cascade_t;
  30
  31 static irq_cascade_t irq_cascade[NR_IRQS] __cacheline_aligned;
  32
  33 static struct irqaction cascade_irqaction = {
  34         .handler        = no_action,
  35         .mask           = CPU_MASK_NONE,
  36         .name           = "cascade",
  37 };
  38
  39 int cascade_irq(unsigned int irq, int (*get_irq)(unsigned int))
  40 {
  41         int retval = 0;
  42
  43         if (irq >= NR_IRQS)
  44                 return -EINVAL;
  45
  46         if (irq_cascade[irq].get_irq != NULL)
  47                 free_irq(irq, NULL);
  48
  49         irq_cascade[irq].get_irq = get_irq;
  50
  51         if (get_irq != NULL) {
  52                 retval = setup_irq(irq, &cascade_irqaction);
  53                 if (retval < 0)
  54                         irq_cascade[irq].get_irq = NULL;
  55         }
  56
  57         return retval;
  58 }
  59
  60 EXPORT_SYMBOL_GPL(cascade_irq);
  61
  62 static void irq_dispatch(unsigned int irq)
  63 {
  64         irq_cascade_t *cascade;
  65         struct irq_desc *desc;
  66
  67         if (irq >= NR_IRQS) {
  68                 atomic_inc(&irq_err_count);
  69                 return;
  70         }
  71
  72         cascade = irq_cascade + irq;
  73         if (cascade->get_irq != NULL) {
  74                 unsigned int source_irq = irq;
  75                 desc = irq_desc + source_irq;
  76                 if (desc->chip->mask_ack)
  77                         desc->chip->mask_ack(source_irq);
  78                 else {
  79                         desc->chip->mask(source_irq);
  80                         desc->chip->ack(source_irq);
  81                 }
  82                 irq = cascade->get_irq(irq);
  83                 if (irq < 0)
  84                         atomic_inc(&irq_err_count);
  85                 else
  86                         irq_dispatch(irq);
  87                 if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
  88                         desc->chip->unmask(source_irq);
  89         } else
  90                 do_IRQ(irq);
  91 }
  92
  93 asmlinkage void plat_irq_dispatch(void)
  94 {
  95         unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
  96
  97         if (pending & CAUSEF_IP7)
  98                 do_IRQ(7);
  99         else if (pending & 0x7800) {
 100                 if (pending & CAUSEF_IP3)
 101                         irq_dispatch(3);
 102                 else if (pending & CAUSEF_IP4)
 103                         irq_dispatch(4);
 104                 else if (pending & CAUSEF_IP5)
 105                         irq_dispatch(5);
 106                 else if (pending & CAUSEF_IP6)
 107                         irq_dispatch(6);
 108         } else if (pending & CAUSEF_IP2)
 109                 irq_dispatch(2);
 110         else if (pending & CAUSEF_IP0)
 111                 do_IRQ(0);
 112         else if (pending & CAUSEF_IP1)
 113                 do_IRQ(1);
 114         else
 115                 spurious_interrupt();
 116 }
 117
 118 void __init arch_init_irq(void)
 119 {
 120         mips_cpu_irq_init(MIPS_CPU_IRQ_BASE);
 121 }