arch/mips/vr41xx/common/irq.c

   1 /*
   2  *  Interrupt handing routines for NEC VR4100 series.
   3  *
   4  *  Copyright (C) 2005-2007  Yoichi Yuasa <yuasa@linux-mips.org>
   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 #include <linux/irq.h>
  23
  24 #include <asm/irq_cpu.h>
  25 #include <asm/system.h>
  26 #include <asm/vr41xx/irq.h>
  27
  28 typedef struct irq_cascade {
  29         int (*get_irq)(unsigned int);
  30 } irq_cascade_t;
  31
  32 static irq_cascade_t irq_cascade[NR_IRQS] __cacheline_aligned;
  33
  34 static struct irqaction cascade_irqaction = {
  35         .handler        = no_action,
  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                 int ret;
  76                 desc = irq_desc + source_irq;
  77                 if (desc->chip->mask_ack)
  78                         desc->chip->mask_ack(source_irq);
  79                 else {
  80                         desc->chip->mask(source_irq);
  81                         desc->chip->ack(source_irq);
  82                 }
  83                 ret = cascade->get_irq(irq);
  84                 irq = ret;
  85                 if (ret < 0)
  86                         atomic_inc(&irq_err_count);
  87                 else
  88                         irq_dispatch(irq);
  89                 if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
  90                         desc->chip->unmask(source_irq);
  91         } else
  92                 do_IRQ(irq);
  93 }
  94
  95 asmlinkage void plat_irq_dispatch(void)
  96 {
  97         unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
  98
  99         if (pending & CAUSEF_IP7)
 100                 do_IRQ(TIMER_IRQ);
 101         else if (pending & 0x7800) {
 102                 if (pending & CAUSEF_IP3)
 103                         irq_dispatch(INT1_IRQ);
 104                 else if (pending & CAUSEF_IP4)
 105                         irq_dispatch(INT2_IRQ);
 106                 else if (pending & CAUSEF_IP5)
 107                         irq_dispatch(INT3_IRQ);
 108                 else if (pending & CAUSEF_IP6)
 109                         irq_dispatch(INT4_IRQ);
 110         } else if (pending & CAUSEF_IP2)
 111                 irq_dispatch(INT0_IRQ);
 112         else if (pending & CAUSEF_IP0)
 113                 do_IRQ(MIPS_SOFTINT0_IRQ);
 114         else if (pending & CAUSEF_IP1)
 115                 do_IRQ(MIPS_SOFTINT1_IRQ);
 116         else
 117                 spurious_interrupt();
 118 }
 119
 120 void __init arch_init_irq(void)
 121 {
 122         mips_cpu_irq_init();
 123 }