LXR linux/arch/arm/mach-footbridge/isa-irq.c

   1/*
   2 *  linux/arch/arm/mach-footbridge/irq.c
   3 *
   4 *  Copyright (C) 1996-2000 Russell King
   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 version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 *  Changelog:
  11 *   22-Aug-1998 RMK    Restructured IRQ routines
  12 *   03-Sep-1998 PJB    Merged CATS support
  13 *   20-Jan-1998 RMK    Started merge of EBSA286, CATS and NetWinder
  14 *   26-Jan-1999 PJB    Don't use IACK on CATS
  15 *   16-Mar-1999 RMK    Added autodetect of ISA PICs
  16 */
  17#include <linux/ioport.h>
  18#include <linux/interrupt.h>
  19#include <linux/list.h>
  20#include <linux/init.h>
  21#include <linux/io.h>
  22#include <linux/spinlock.h>
  23
  24#include <asm/mach/irq.h>
  25
  26#include <mach/hardware.h>
  27#include <asm/hardware/dec21285.h>
  28#include <asm/irq.h>
  29#include <asm/mach-types.h>
  30
  31#include "common.h"
  32
  33static void isa_mask_pic_lo_irq(unsigned int irq)
  34{
  35        unsigned int mask = 1 << (irq & 7);
  36
  37        outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
  38}
  39
  40static void isa_ack_pic_lo_irq(unsigned int irq)
  41{
  42        unsigned int mask = 1 << (irq & 7);
  43
  44        outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
  45        outb(0x20, PIC_LO);
  46}
  47
  48static void isa_unmask_pic_lo_irq(unsigned int irq)
  49{
  50        unsigned int mask = 1 << (irq & 7);
  51
  52        outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
  53}
  54
  55static struct irq_chip isa_lo_chip = {
  56        .ack    = isa_ack_pic_lo_irq,
  57        .mask   = isa_mask_pic_lo_irq,
  58        .unmask = isa_unmask_pic_lo_irq,
  59};
  60
  61static void isa_mask_pic_hi_irq(unsigned int irq)
  62{
  63        unsigned int mask = 1 << (irq & 7);
  64
  65        outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
  66}
  67
  68static void isa_ack_pic_hi_irq(unsigned int irq)
  69{
  70        unsigned int mask = 1 << (irq & 7);
  71
  72        outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
  73        outb(0x62, PIC_LO);
  74        outb(0x20, PIC_HI);
  75}
  76
  77static void isa_unmask_pic_hi_irq(unsigned int irq)
  78{
  79        unsigned int mask = 1 << (irq & 7);
  80
  81        outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
  82}
  83
  84static struct irq_chip isa_hi_chip = {
  85        .ack    = isa_ack_pic_hi_irq,
  86        .mask   = isa_mask_pic_hi_irq,
  87        .unmask = isa_unmask_pic_hi_irq,
  88};
  89
  90static void
  91isa_irq_handler(unsigned int irq, struct irq_desc *desc)
  92{
  93        unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
  94
  95        if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
  96                do_bad_IRQ(isa_irq, desc);
  97                return;
  98        }
  99
 100        generic_handle_irq(isa_irq);
 101}
 102
 103static struct irqaction irq_cascade = {
 104        .handler = no_action,
 105        .name = "cascade",
 106};
 107
 108static struct resource pic1_resource = {
 109        .name   = "pic1",
 110        .start  = 0x20,
 111        .end    = 0x3f,
 112};
 113
 114static struct resource pic2_resource = {
 115        .name   = "pic2",
 116        .start  = 0xa0,
 117        .end    = 0xbf,
 118};
 119
 120void __init isa_init_irq(unsigned int host_irq)
 121{
 122        unsigned int irq;
 123
 124        /*
 125         * Setup, and then probe for an ISA PIC
 126         * If the PIC is not there, then we
 127         * ignore the PIC.
 128         */
 129        outb(0x11, PIC_LO);
 130        outb(_ISA_IRQ(0), PIC_MASK_LO); /* IRQ number           */
 131        outb(0x04, PIC_MASK_LO);        /* Slave on Ch2         */
 132        outb(0x01, PIC_MASK_LO);        /* x86                  */
 133        outb(0xf5, PIC_MASK_LO);        /* pattern: 11110101    */
 134
 135        outb(0x11, PIC_HI);
 136        outb(_ISA_IRQ(8), PIC_MASK_HI); /* IRQ number           */
 137        outb(0x02, PIC_MASK_HI);        /* Slave on Ch1         */
 138        outb(0x01, PIC_MASK_HI);        /* x86                  */
 139        outb(0xfa, PIC_MASK_HI);        /* pattern: 11111010    */
 140
 141        outb(0x0b, PIC_LO);
 142        outb(0x0b, PIC_HI);
 143
 144        if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
 145                outb(0xff, PIC_MASK_LO);/* mask all IRQs        */
 146                outb(0xff, PIC_MASK_HI);/* mask all IRQs        */
 147        } else {
 148                printk(KERN_INFO "IRQ: ISA PIC not found\n");
 149                host_irq = (unsigned int)-1;
 150        }
 151
 152        if (host_irq != (unsigned int)-1) {
 153                for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
 154                        set_irq_chip(irq, &isa_lo_chip);
 155                        set_irq_handler(irq, handle_level_irq);
 156                        set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
 157                }
 158
 159                for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
 160                        set_irq_chip(irq, &isa_hi_chip);
 161                        set_irq_handler(irq, handle_level_irq);
 162                        set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
 163                }
 164
 165                request_resource(&ioport_resource, &pic1_resource);
 166                request_resource(&ioport_resource, &pic2_resource);
 167                setup_irq(IRQ_ISA_CASCADE, &irq_cascade);
 168
 169                set_irq_chained_handler(host_irq, isa_irq_handler);
 170
 171                /*
 172                 * On the NetWinder, don't automatically
 173                 * enable ISA IRQ11 when it is requested.
 174                 * There appears to be a missing pull-up
 175                 * resistor on this line.
 176                 */
 177                if (machine_is_netwinder())
 178                        set_irq_flags(_ISA_IRQ(11), IRQF_VALID |
 179                                      IRQF_PROBE | IRQF_NOAUTOEN);
 180        }
 181}
 182
 183
 184