linux/arch/mips/lasat/interrupt.c
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   1/*
   2 * Carsten Langgaard, carstenl@mips.com
   3 * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
   4 *
   5 *  This program is free software; you can distribute it and/or modify it
   6 *  under the terms of the GNU General Public License (Version 2) as
   7 *  published by the Free Software Foundation.
   8 *
   9 *  This program is distributed in the hope it will be useful, but WITHOUT
  10 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 *  for more details.
  13 *
  14 *  You should have received a copy of the GNU General Public License along
  15 *  with this program; if not, write to the Free Software Foundation, Inc.,
  16 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  17 *
  18 * Routines for generic manipulation of the interrupts found on the
  19 * Lasat boards.
  20 */
  21#include <linux/init.h>
  22#include <linux/interrupt.h>
  23#include <linux/irq.h>
  24
  25#include <asm/irq_cpu.h>
  26#include <asm/lasat/lasat.h>
  27#include <asm/lasat/lasatint.h>
  28
  29#include <irq.h>
  30
  31static volatile int *lasat_int_status;
  32static volatile int *lasat_int_mask;
  33static volatile int lasat_int_mask_shift;
  34
  35void disable_lasat_irq(unsigned int irq_nr)
  36{
  37        irq_nr -= LASAT_IRQ_BASE;
  38        *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  39}
  40
  41void enable_lasat_irq(unsigned int irq_nr)
  42{
  43        irq_nr -= LASAT_IRQ_BASE;
  44        *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  45}
  46
  47static struct irq_chip lasat_irq_type = {
  48        .name = "Lasat",
  49        .ack = disable_lasat_irq,
  50        .mask = disable_lasat_irq,
  51        .mask_ack = disable_lasat_irq,
  52        .unmask = enable_lasat_irq,
  53};
  54
  55static inline int ls1bit32(unsigned int x)
  56{
  57        int b = 31, s;
  58
  59        s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  60        s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  61        s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  62        s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  63        s =  1; if (x <<  1 == 0) s = 0; b -= s;
  64
  65        return b;
  66}
  67
  68static unsigned long (*get_int_status)(void);
  69
  70static unsigned long get_int_status_100(void)
  71{
  72        return *lasat_int_status & *lasat_int_mask;
  73}
  74
  75static unsigned long get_int_status_200(void)
  76{
  77        unsigned long int_status;
  78
  79        int_status = *lasat_int_status;
  80        int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
  81        return int_status;
  82}
  83
  84asmlinkage void plat_irq_dispatch(void)
  85{
  86        unsigned long int_status;
  87        unsigned int cause = read_c0_cause();
  88        int irq;
  89
  90        if (cause & CAUSEF_IP7) {       /* R4000 count / compare IRQ */
  91                do_IRQ(7);
  92                return;
  93        }
  94
  95        int_status = get_int_status();
  96
  97        /* if int_status == 0, then the interrupt has already been cleared */
  98        if (int_status) {
  99                irq = LASAT_IRQ_BASE + ls1bit32(int_status);
 100
 101                do_IRQ(irq);
 102        }
 103}
 104
 105static struct irqaction cascade = {
 106        .handler        = no_action,
 107        .mask           = CPU_MASK_NONE,
 108        .name           = "cascade",
 109};
 110
 111void __init arch_init_irq(void)
 112{
 113        int i;
 114
 115        if (IS_LASAT_200()) {
 116                lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 117                lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 118                lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 119                get_int_status = get_int_status_200;
 120                *lasat_int_mask &= 0xffff;
 121        } else {
 122                lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 123                lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 124                lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 125                get_int_status = get_int_status_100;
 126                *lasat_int_mask = 0;
 127        }
 128
 129        mips_cpu_irq_init();
 130
 131        for (i = LASAT_IRQ_BASE; i <= LASAT_IRQ_END; i++)
 132                set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
 133
 134        setup_irq(LASAT_CASCADE_IRQ, &cascade);
 135}
 136