/**
 * PROJECT:         ExectOS
 * COPYRIGHT:       See COPYING.md in the top level directory
 * FILE:            xtoskrnl/hl/pic.c
 * DESCRIPTION:     Programmable Interrupt Controller (PIC) support
 * DEVELOPERS:      Rafal Kupiec <belliash@codingworkshop.eu.org>
 *                  Jozef Nagy <schkwve@gmail.com>
 */

#include <xtos.h>

/**
 * Initializes the 8259 PIC.
 * 
 * @return This routine does not return any value.
 * 
 * @since XT 1.0
 */
XTCDECL
VOID
HlInitializePic(VOID)
{
    /* Start in cascade mode */
    HlWritePic(PIC_MASTER_COMMAND, PIC_ICW1_INIT | PIC_ICW1_ICW4);
    HlWritePic(PIC_SLAVE_COMMAND, PIC_ICW1_INIT | PIC_ICW1_ICW4);

    /* Master PIC Vector offset */
    HlWritePic(PIC_MASTER_DATA, 0x20);
    /* Slave PIC Vector offset */
    HlWritePic(PIC_SLAVE_DATA, 0x28);

    /* Tell Master PIC that there is a Slave PIC */
    HlWritePic(PIC_MASTER_DATA, 4);
    /* Tell Slave PIC its cascade identity */
    HlWritePic(PIC_SLAVE_DATA, 2);
 
    /* Tell Master PIC to use 8086 mode */
    HlWritePic(PIC_MASTER_DATA, PIC_ICW4_8086);
    /* Tell Slave PIC to use 8086 mode */
    HlWritePic(PIC_SLAVE_DATA, PIC_ICW4_8086);

    /* Mask all IRQs by default */
    for (UCHAR Irq = 0; Irq < 16; Irq++)
    {
        HlSetMaskIrqPic(Irq);
    }
}

/**
 * Masks an IRQ in the 8259 PIC.
 * 
 * @param Irq
 *        Supplies the IRQ number to be masked.
 * 
 * @return This routine does not return any value.
 * 
 * @since XT 1.0
 */
XTCDECL
VOID
HlSetMaskIrqPic(UINT Irq)
{
    UINT Port;
 
    if(Irq < 8) {
        Port = PIC_MASTER_DATA;
    } else {
        Port = PIC_SLAVE_DATA;
        Irq -= 8;
    }

    HlWritePic(Port, HlIoPortInByte(Port) | (1 << Irq));
}

/**
 * Clears an IRQ mask in the 8259 PIC.
 * 
 * @param Irq
 *        Supplies the IRQ number to be unmasked.
 * 
 * @return This routine does not return any value.
 * 
 * @since XT 1.0
 */
XTCDECL
VOID
HlClearMaskIrqPic(UINT Irq)
{
    UINT Port;
 
    if(Irq < 8) {
        Port = PIC_MASTER_DATA;
    } else {
        Port = PIC_SLAVE_DATA;
        Irq -= 8;
    }

    HlWritePic(Port, HlIoPortInByte(Port) & ~(1 << Irq));
}

/**
 * Disables the 8259 PIC.
 *
 * @return This routine does not return any value.
 *
 * @since XT 1.0
 */
XTCDECL
VOID
HlDisablePic(VOID)
{
    HlIoPortOutByte(PIC_MASTER_DATA, 0xFF);
    HlIoPortOutByte(PIC_SLAVE_DATA, 0xFF);
}

XTFASTCALL
VOID
HlWritePic(IN UCHAR Register, IN UCHAR Value)
{
    /* Send data */
    HlIoPortOutByte(Register, Value);
    /* Wait for some time to make sure PIC has processed the data */
    HlIoPortWait();
}

/**
 * Reads from the local APIC register.
 *
 * @param Register
 *        Supplies the APIC register to read from.
 *
 * @return This routine returns the value read from the APIC register.
 *
 * @since XT 1.0
 */
XTFASTCALL
ULONG
HlReadApicRegister(IN APIC_REGISTER Register)
{
    return RtlReadRegisterLong((PULONG)APIC_BASE + (Register << 4));
}

/**
 * Writes to the local APIC register.
 *
 * @param Register
 *        Supplies the APIC register to write to.
 *
 * @param Value
 *        Supplies the value to write to the APIC register.
 *
 * @return This routine does not return any value.
 *
 * @since XT 1.0
 */
XTFASTCALL
VOID
HlWriteApicRegister(IN APIC_REGISTER Register,
                    IN ULONG Value)
{
    RtlWriteRegisterLong((PULONG)APIC_BASE + (Register << 4), Value);
}