isa-irq.c

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/*
 *  linux/arch/arm/mach-footbridge/irq.c
 *
 *  Copyright (C) 1996-2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Changelog:
 *   22-Aug-1998 RMK    Restructured IRQ routines
 *   03-Sep-1998 PJB    Merged CATS support
 *   20-Jan-1998 RMK    Started merge of EBSA286, CATS and NetWinder
 *   26-Jan-1999 PJB    Don't use IACK on CATS
 *   16-Mar-1999 RMK    Added autodetect of ISA PICs
 */
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/spinlock.h>

#include <asm/mach/irq.h>

#include <mach/hardware.h>
#include <asm/hardware/dec21285.h>
#include <asm/irq.h>
#include <asm/mach-types.h>

#include "common.h"

static void isa_mask_pic_lo_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
}

static void isa_ack_pic_lo_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
    outb(0x20, PIC_LO);
}

static void isa_unmask_pic_lo_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
}

static struct irq_chip isa_lo_chip = {
    .irq_ack    = isa_ack_pic_lo_irq,
    .irq_mask   = isa_mask_pic_lo_irq,
    .irq_unmask = isa_unmask_pic_lo_irq,
};

static void isa_mask_pic_hi_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
}

static void isa_ack_pic_hi_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
    outb(0x62, PIC_LO);
    outb(0x20, PIC_HI);
}

static void isa_unmask_pic_hi_irq(struct irq_data *d)
{
    unsigned int mask = 1 << (d->irq & 7);

    outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
}

static struct irq_chip isa_hi_chip = {
    .irq_ack    = isa_ack_pic_hi_irq,
    .irq_mask   = isa_mask_pic_hi_irq,
    .irq_unmask = isa_unmask_pic_hi_irq,
};

static void
isa_irq_handler(unsigned int irq, struct irq_desc *desc)
{
    unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;

    if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
        do_bad_IRQ(isa_irq, desc);
        return;
    }

    generic_handle_irq(isa_irq);
}

static struct irqaction irq_cascade = {
    .handler = no_action,
    .name = "cascade",
};

static struct resource pic1_resource = {
    .name   = "pic1",
    .start  = 0x20,
    .end    = 0x3f,
};

static struct resource pic2_resource = {
    .name   = "pic2",
    .start  = 0xa0,
    .end    = 0xbf,
};

void __init isa_init_irq(unsigned int host_irq)
{
    unsigned int irq;

    /*
     * Setup, and then probe for an ISA PIC
     * If the PIC is not there, then we
     * ignore the PIC.
     */
    outb(0x11, PIC_LO);
    outb(_ISA_IRQ(0), PIC_MASK_LO); /* IRQ number       */
    outb(0x04, PIC_MASK_LO);    /* Slave on Ch2     */
    outb(0x01, PIC_MASK_LO);    /* x86          */
    outb(0xf5, PIC_MASK_LO);    /* pattern: 11110101    */

    outb(0x11, PIC_HI);
    outb(_ISA_IRQ(8), PIC_MASK_HI); /* IRQ number       */
    outb(0x02, PIC_MASK_HI);    /* Slave on Ch1     */
    outb(0x01, PIC_MASK_HI);    /* x86          */
    outb(0xfa, PIC_MASK_HI);    /* pattern: 11111010    */

    outb(0x0b, PIC_LO);
    outb(0x0b, PIC_HI);

    if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
        outb(0xff, PIC_MASK_LO);/* mask all IRQs    */
        outb(0xff, PIC_MASK_HI);/* mask all IRQs    */
    } else {
        printk(KERN_INFO "IRQ: ISA PIC not found\n");
        host_irq = (unsigned int)-1;
    }

    if (host_irq != (unsigned int)-1) {
        for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
            irq_set_chip_and_handler(irq, &isa_lo_chip,
                         handle_level_irq);
            set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
        }

        for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
            irq_set_chip_and_handler(irq, &isa_hi_chip,
                         handle_level_irq);
            set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
        }

        request_resource(&ioport_resource, &pic1_resource);
        request_resource(&ioport_resource, &pic2_resource);
        setup_irq(IRQ_ISA_CASCADE, &irq_cascade);

        irq_set_chained_handler(host_irq, isa_irq_handler);

        /*
         * On the NetWinder, don't automatically
         * enable ISA IRQ11 when it is requested.
         * There appears to be a missing pull-up
         * resistor on this line.
         */
        if (machine_is_netwinder())
            set_irq_flags(_ISA_IRQ(11), IRQF_VALID |
                      IRQF_PROBE | IRQF_NOAUTOEN);
    }
}