source: mainline/arch/ia32/src/drivers/i8259.c@ f761f1eb

/*
 * Copyright (C) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <arch/i8259.h>
#include <cpu.h>
#include <arch/types.h>
#include <arch/asm.h>
#include <arch.h>

/*
 * This is the PIC driver.
 * Programmable Interrupt Controller for UP systems.
 */

void i8259_init(void)
{
        /* ICW1: this is ICW1, ICW4 to follow */
        outb(PIC_PIC0PORT1, PIC_ICW1 | PIC_NEEDICW4);

        /* ICW2: IRQ 0 maps to INT IRQBASE */
        outb(PIC_PIC0PORT2, IVT_IRQBASE);
    
        /* ICW3: pic1 using IRQ IRQ_PIC1 */
        outb(PIC_PIC0PORT2, 1 << IRQ_PIC1);
    
        /* ICW4: i8086 mode */    
        outb(PIC_PIC0PORT2, 1);

        /* ICW1: ICW1, ICW4 to follow */
        outb(PIC_PIC1PORT1, PIC_ICW1 | PIC_NEEDICW4);

        /* ICW2: IRQ 8 maps to INT (IVT_IRQBASE + 8) */    
        outb(PIC_PIC1PORT2, IVT_IRQBASE + 8);

        /* ICW3: pic1 is known as PIC_PIC1ID */
        outb(PIC_PIC1PORT2, PIC_PIC1ID);

        /* ICW4: i8086 mode */    
        outb(PIC_PIC1PORT2, 1);

        /*
         * Register interrupt handler for the PIC spurious interrupt.
         */
        trap_register(VECTOR_PIC_SPUR, pic_spurious);   

        /*
         * Set the enable/disable IRQs handlers.
         * Set the End-of-Interrupt handler.
         */
        enable_irqs_function = pic_enable_irqs;
        disable_irqs_function = pic_disable_irqs;
        eoi_function = pic_eoi;
    
        pic_disable_irqs(0xffff);               /* disable all irq's */
        pic_enable_irqs(1<<IRQ_PIC1);           /* but enable pic1 */
}

void pic_enable_irqs(__u16 irqmask)
{
        __u8 x;
    
        if (irqmask & 0xff) {
                x = inb(PIC_PIC0PORT2);
                outb(PIC_PIC0PORT2, x & (~(irqmask & 0xff)));
        }
        if (irqmask >> 8) {
                x = inb(PIC_PIC1PORT2);
                outb(PIC_PIC1PORT2, x & (~(irqmask >> 8)));
        }
}

void pic_disable_irqs(__u16 irqmask)
{
        __u8 x;
    
        if (irqmask & 0xff) {
                x = inb(PIC_PIC0PORT2);
                outb(PIC_PIC0PORT2, x | (irqmask & 0xff));
        }
        if (irqmask >> 8) {
                x = inb(PIC_PIC1PORT2);
                outb(PIC_PIC1PORT2, x | (irqmask >> 8));
        }
}

void pic_eoi(void)
{
        outb(0x20,0x20);
        outb(0xa0,0x20);
}

void pic_spurious(__u8 n, __u32 stack[])
{
        printf("cpu%d: PIC spurious interrupt\n", the->cpu->id);
}