arch/mips/vr41xx/common/irq.c

   1 /*
   2  *  Interrupt handing routines for NEC VR4100 series.
   3  *
   4  *  Copyright (C) 2005  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/vr41xx.h>
  26
  27 typedef struct irq_cascade {
  28         int (*get_irq)(unsigned int, struct pt_regs *);
  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, struct pt_regs *))
  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 asmlinkage void irq_dispatch(unsigned int irq, struct pt_regs *regs)
  63 {
  64         irq_cascade_t *cascade;
  65         irq_desc_t *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                 desc->handler->ack(source_irq);
  77                 irq = cascade->get_irq(irq, regs);
  78                 if (irq < 0)
  79                         atomic_inc(&irq_err_count);
  80                 else
  81                         irq_dispatch(irq, regs);
  82                 desc->handler->end(source_irq);
  83         } else
  84                 do_IRQ(irq, regs);
  85 }
  86
  87 extern asmlinkage void vr41xx_handle_interrupt(void);
  88
  89 void __init arch_init_irq(void)
  90 {
  91         mips_cpu_irq_init(MIPS_CPU_IRQ_BASE);
  92
  93         set_except_vector(0, vr41xx_handle_interrupt);
  94 }