source: mainline/kernel/arch/ia32/src/drivers/i8259.c@ d99c1d2

/*
 * 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.
 */

/** @addtogroup ia32    
 * @{
 */
/**
 * @file
 * @brief PIC driver.
 *
 * Programmable Interrupt Controller for UP systems based on i8259 chip.
 */

#include <arch/drivers/i8259.h>
#include <cpu.h>
#include <typedefs.h>
#include <arch/asm.h>
#include <arch.h>
#include <print.h>
#include <interrupt.h>

static void pic_spurious(int n, istate_t *istate);

void i8259_init(void)
{
        /* ICW1: this is ICW1, ICW4 to follow */
        pio_write_8(PIC_PIC0PORT1, PIC_ICW1 | PIC_NEEDICW4);

        /* ICW2: IRQ 0 maps to INT IRQBASE */
        pio_write_8(PIC_PIC0PORT2, IVT_IRQBASE);

        /* ICW3: pic1 using IRQ IRQ_PIC1 */
        pio_write_8(PIC_PIC0PORT2, 1 << IRQ_PIC1);

        /* ICW4: i8086 mode */
        pio_write_8(PIC_PIC0PORT2, 1);

        /* ICW1: ICW1, ICW4 to follow */
        pio_write_8(PIC_PIC1PORT1, PIC_ICW1 | PIC_NEEDICW4);

        /* ICW2: IRQ 8 maps to INT (IVT_IRQBASE + 8) */
        pio_write_8(PIC_PIC1PORT2, IVT_IRQBASE + 8);

        /* ICW3: pic1 is known as IRQ_PIC1 */
        pio_write_8(PIC_PIC1PORT2, IRQ_PIC1);

        /* ICW4: i8086 mode */
        pio_write_8(PIC_PIC1PORT2, 1);

        /*
         * Register interrupt handler for the PIC spurious interrupt.
         */
        exc_register(VECTOR_PIC_SPUR, "pic_spurious", (iroutine) 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(uint16_t irqmask)
{
        uint8_t x;

        if (irqmask & 0xff) {
                x = pio_read_8(PIC_PIC0PORT2);
                pio_write_8(PIC_PIC0PORT2, (uint8_t) (x & (~(irqmask & 0xff))));
        }
        if (irqmask >> 8) {
                x = pio_read_8(PIC_PIC1PORT2);
                pio_write_8(PIC_PIC1PORT2, (uint8_t) (x & (~(irqmask >> 8))));
        }
}

void pic_disable_irqs(uint16_t irqmask)
{
        uint8_t x;

        if (irqmask & 0xff) {
                x = pio_read_8(PIC_PIC0PORT2);
                pio_write_8(PIC_PIC0PORT2, (uint8_t) (x | (irqmask & 0xff)));
        }
        if (irqmask >> 8) {
                x = pio_read_8(PIC_PIC1PORT2);
                pio_write_8(PIC_PIC1PORT2, (uint8_t) (x | (irqmask >> 8)));
        }
}

void pic_eoi(void)
{
        pio_write_8((ioport8_t *)0x20, 0x20);
        pio_write_8((ioport8_t *)0xa0, 0x20);
}

void pic_spurious(int n __attribute__((unused)), istate_t *istate __attribute__((unused)))
{
#ifdef CONFIG_DEBUG
        printf("cpu%u: PIC spurious interrupt\n", CPU->id);
#endif
}

/** @}
 */