release/src-rt-6.x.4708/linux/linux-2.6.36/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
  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         .name           = "cascade",
  36 };
  37
  38 int cascade_irq(unsigned int irq, int (*get_irq)(unsigned int))
  39 {
  40         int retval = 0;
  41
  42         if (irq >= NR_IRQS)
  43                 return -EINVAL;
  44
  45         if (irq_cascade[irq].get_irq != NULL)
  46                 free_irq(irq, NULL);
  47
  48         irq_cascade[irq].get_irq = get_irq;
  49
  50         if (get_irq != NULL) {
  51                 retval = setup_irq(irq, &cascade_irqaction);
  52                 if (retval < 0)
  53                         irq_cascade[irq].get_irq = NULL;
  54         }
  55
  56         return retval;
  57 }
  58
  59 EXPORT_SYMBOL_GPL(cascade_irq);
  60
  61 static void irq_dispatch(unsigned int irq)
  62 {
  63         irq_cascade_t *cascade;
  64         struct irq_desc *desc;
  65
  66         if (irq >= NR_IRQS) {
  67                 atomic_inc(&irq_err_count);
  68                 return;
  69         }
  70
  71         cascade = irq_cascade + irq;
  72         if (cascade->get_irq != NULL) {
  73                 unsigned int source_irq = irq;
  74                 int ret;
  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                 ret = cascade->get_irq(irq);
  83                 irq = ret;
  84                 if (ret < 0)
  85                         atomic_inc(&irq_err_count);
  86                 else
  87                         irq_dispatch(irq);
  88                 if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
  89                         desc->chip->unmask(source_irq);
  90         } else
  91                 do_IRQ(irq);
  92 }
  93
  94 asmlinkage void plat_irq_dispatch(void)
  95 {
  96         unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
  97
  98         if (pending & CAUSEF_IP7)
  99                 do_IRQ(TIMER_IRQ);
 100         else if (pending & 0x7800) {
 101                 if (pending & CAUSEF_IP3)
 102                         irq_dispatch(INT1_IRQ);
 103                 else if (pending & CAUSEF_IP4)
 104                         irq_dispatch(INT2_IRQ);
 105                 else if (pending & CAUSEF_IP5)
 106                         irq_dispatch(INT3_IRQ);
 107                 else if (pending & CAUSEF_IP6)
 108                         irq_dispatch(INT4_IRQ);
 109         } else if (pending & CAUSEF_IP2)
 110                 irq_dispatch(INT0_IRQ);
 111         else if (pending & CAUSEF_IP0)
 112                 do_IRQ(MIPS_SOFTINT0_IRQ);
 113         else if (pending & CAUSEF_IP1)
 114                 do_IRQ(MIPS_SOFTINT1_IRQ);
 115         else
 116                 spurious_interrupt();
 117 }
 118
 119 void __init arch_init_irq(void)
 120 {
 121         mips_cpu_irq_init();
 122 }