/*! @file       eltorito.c
    Copyright 2007 VMware Inc.
    Author: David Elliott
 */

#include "boot.h"

//==========================================================================
// El Torito calls
static biosBuf_t bb;

// True if the address can be represented in real mode
// i.e. it is only 20 bits
// NOTE: Yes.. I do know about the UMA hack.. but that's silly for our purposes
#define IS_ADDR_REAL(addr32) (((addr32) & ~0xFFFFF) == 0)

// Returns the El Torito return code (AH)
int elToritoGetStatus(int biosdev, struct el_torito_spec_packet *p_cd_spec)
{
    struct el_torito_spec_packet cd_spec;
    struct el_torito_spec_packet *_p_cd_spec = ((p_cd_spec != NULL) && IS_ADDR_REAL((uint32_t)p_cd_spec))?p_cd_spec:&cd_spec;
    bzero(_p_cd_spec, sizeof(struct el_torito_spec_packet));
    _p_cd_spec->packet_size = sizeof(struct el_torito_spec_packet);

    bb.intno = 0x13;
    bb.eax.r.h = 0x4b;
    bb.eax.r.l = 1; // Status only.  Do not terminate
    bb.edx.rx = biosdev;
    bb.esi.rr = OFFSET((uint32_t)_p_cd_spec);
    bb.ds = SEGMENT((uint32_t)_p_cd_spec);
    bios(&bb);
    if(p_cd_spec != NULL && _p_cd_spec != p_cd_spec)
        bcopy(_p_cd_spec, p_cd_spec, sizeof(struct el_torito_spec_packet));
    return bb.eax.r.h;
}

// Terminating then initiating the emulation does not seem to work
// and is not needed anyway as the disc can be replaced without it.
#if 0
// Returns the El Torito return code (AH)
int elToritoInitiateDiskEmulation(int biosdev, struct el_torito_spec_packet *p_cd_spec)
{
    struct el_torito_spec_packet cd_spec;
    struct el_torito_spec_packet *_p_cd_spec = ((p_cd_spec != NULL) && IS_ADDR_REAL((uint32_t)p_cd_spec))?p_cd_spec:&cd_spec;
    if(p_cd_spec == NULL)
        stop("Cannot initiate El Torito emulation without knowing the specification packet");
    if(_p_cd_spec != p_cd_spec)
        bcopy(p_cd_spec, _p_cd_spec, sizeof(struct el_torito_spec_packet));

    bb.intno = 0x13;
    bb.eax.r.h = 0x4a;
    bb.eax.r.l = 0; // Initiate
    bb.edx.rx = biosdev;
    bb.esi.rr = OFFSET((uint32_t)_p_cd_spec);
    bb.ds = SEGMENT((uint32_t)_p_cd_spec);
    bios(&bb);
    if(p_cd_spec != NULL && _p_cd_spec != p_cd_spec)
        bcopy(_p_cd_spec, p_cd_spec, sizeof(struct el_torito_spec_packet));
    return bb.eax.r.h;
}
#endif

// Returns the El Torito return code (AH)
int elToritoTerminateDiskEmulation(int biosdev, struct el_torito_spec_packet *p_cd_spec)
{
    struct el_torito_spec_packet cd_spec;
    struct el_torito_spec_packet *_p_cd_spec = ((p_cd_spec != NULL) && IS_ADDR_REAL((uint32_t)p_cd_spec))?p_cd_spec:&cd_spec;
    bzero(_p_cd_spec, sizeof(struct el_torito_spec_packet));
    _p_cd_spec->packet_size = sizeof(struct el_torito_spec_packet);

    bb.intno = 0x13;
    bb.eax.r.h = 0x4b;
    bb.eax.r.l = 0; // Terminate
    bb.edx.rx = biosdev;
    bb.esi.rr = OFFSET((uint32_t)_p_cd_spec);
    bb.ds = SEGMENT((uint32_t)_p_cd_spec);
    bios(&bb);
    if(p_cd_spec != NULL && _p_cd_spec != p_cd_spec)
        bcopy(_p_cd_spec, p_cd_spec, sizeof(struct el_torito_spec_packet));
    return bb.eax.r.h;
}