kbd.c

#include "kbd.h"
#include "vga.h"

struct IDT_entry IDT[IDT_SIZE];

void idt_init(void)
{
	unsigned long kbd_addr;
	unsigned long idt_addr;
	unsigned long idt_ptr[2];

	/* populate IDT entry of keyboard's interrupt */
	kbd_addr = (unsigned long)kbd_handler;
	IDT[0x21].offset_lowerbits = kbd_addr & 0xffff;
	IDT[0x21].selector = KERNEL_CODE_SEGMENT_OFFSET;
	IDT[0x21].zero = 0;
	IDT[0x21].type_attr = INTERRUPT_GATE;
	IDT[0x21].offset_higherbits = (kbd_addr & 0xffff0000) >> 16;

	/*     Ports
	*	 PIC1	PIC2
	*Command 0x20	0xA0
	*Data	 0x21	0xA1
	*/

	/* ICW1 - begin initialization */
	write_port(0x20 , 0x11);
	write_port(0xA0 , 0x11);

	/* ICW2 - remap offset address of IDT */
	/*
	* In x86 protected mode, we have to remap the PICs beyond 0x20 because
	* Intel have designated the first 32 interrupts as "reserved" for cpu exceptions
	*/
	write_port(0x21 , 0x20);
	write_port(0xA1 , 0x28);

	/* ICW3 - setup cascading */
	write_port(0x21 , 0x00);
	write_port(0xA1 , 0x00);

	/* ICW4 - environment info */
	write_port(0x21 , 0x01);
	write_port(0xA1 , 0x01);
	/* Initialization finished */

	/* mask interrupts */
	write_port(0x21 , 0xff);
	write_port(0xA1 , 0xff);

	/* fill the IDT descriptor */
	idt_addr = (unsigned long)IDT ;
	idt_ptr[0] = (sizeof (struct IDT_entry) * IDT_SIZE) + ((idt_addr & 0xffff) << 16);
	idt_ptr[1] = idt_addr >> 16 ;

	load_idt(idt_ptr);
}

void kbd_init(void)
{
	/* 0xFD is 11111101 - enables only IRQ1 (keyboard)*/
	write_port(0x21 , 0xFD);
}

void kbd_main(void)
{
        unsigned char status;
        char keycode;

        /* write EOI */
        write_port(0x20, 0x20);

        status = read_port(KBD_STATUS_PORT);
        /* Lowest bit of status will be set if buffer is not empty */
        if (status & 0x01)
        {
                keycode = read_port(KBD_DATA_PORT);
                if (keycode < 0)
                        return;
                if (keycode == ENTER_KEY_CODE)
                {
                        write("\n");
                        return;
                }

                term_putchar(kbd_map[(unsigned char) keycode]);
        }
}