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// license:LGPL-2.1+
// copyright-holders:Angelo Salese, R. Belmont
/*
dc.c - Sega Dreamcast hardware
MESS (DC home console) hardware overrides (GD-ROM drive etc)
c230048 - 5 is written, want 6
c0d9d9e - where bad happens, from routine @ c0da260
c0d9d8e - R0 on return is the value to put in
cfffee0 - stack location when bad happens
TODO:
- gdrom_alt_status is identical to normal status except that "but it does not clear DMA status information when it is accessed"
*/
#include "emu.h"
#include "cdrom.h"
#include "debugger.h"
#include "includes/dc.h"
#include "cpu/sh4/sh4.h"
#include "sound/aica.h"
#include "includes/dccons.h"
#define ATAPI_CYCLES_PER_SECTOR (5000) // TBD for Dreamcast
WRITE_LINE_MEMBER(dc_cons_state::ata_interrupt)
{
if (state)
dc_sysctrl_regs[SB_ISTEXT] |= IST_EXT_GDROM;
else
dc_sysctrl_regs[SB_ISTEXT] &= ~IST_EXT_GDROM;
dc_update_interrupt_status();
}
TIMER_CALLBACK_MEMBER(dc_cons_state::atapi_xfer_end )
{
UINT8 sector_buffer[ 4096 ];
atapi_timer->adjust(attotime::never);
printf("atapi_xfer_end atapi_xferlen = %d\n", atapi_xferlen );
//osd_printf_debug("ATAPI: xfer_end. xferlen = %d\n", atapi_xferlen);
m_ata->write_dmack(1);
while (atapi_xferlen > 0 )
{
struct sh4_ddt_dma ddtdata;
// get a sector from the SCSI device
for (int i = 0; i < 2048/2; i++)
{
int d = m_ata->read_dma();
sector_buffer[ i*2 ] = d & 0xff;
sector_buffer[ (i*2)+1 ] = d >> 8;
}
atapi_xferlen -= 2048;
// perform the DMA
ddtdata.destination = atapi_xferbase; // destination address
ddtdata.length = 2048/4;
ddtdata.size = 4;
ddtdata.buffer = sector_buffer;
ddtdata.direction=1; // 0 source to buffer, 1 buffer to destination
ddtdata.channel= 0;
ddtdata.mode= -1; // copy from/to buffer
printf("ATAPI: DMA one sector to %x, %x remaining\n", atapi_xferbase, atapi_xferlen);
m_maincpu->sh4_dma_ddt(&ddtdata);
atapi_xferbase += 2048;
}
m_ata->write_dmack(0);
g1bus_regs[SB_GDST]=0;
dc_sysctrl_regs[SB_ISTNRM] |= IST_DMA_GDROM;
dc_update_interrupt_status();
}
void dc_cons_state::dreamcast_atapi_init()
{
atapi_timer = machine().scheduler().timer_alloc(timer_expired_delegate(FUNC(dc_cons_state::atapi_xfer_end),this));
atapi_timer->adjust(attotime::never);
save_item(NAME(atapi_xferlen));
save_item(NAME(atapi_xferbase));
}
/*
GDROM regsters:
5f7018: alternate status/device control
5f7080: data
5f7084: error/features
5f7088: interrupt reason/sector count
5f708c: sector number
5f7090: byte control low
5f7094: byte control high
5f7098: drive select
5f709c: status/command
c002910 - ATAPI packet writes
c002796 - aux status read after that
c000776 - DMA triggered to c008000
*/
READ32_MEMBER(dc_cons_state::dc_mess_g1_ctrl_r )
{
switch(offset)
{
case SB_GDSTARD:
printf("G1CTRL: GDSTARD %08x\n", atapi_xferbase); // Hello Kitty reads here
debugger_break(machine());
return atapi_xferbase;
case SB_GDST:
break;
case SB_GDLEND:
//debugger_break(machine());
return atapi_xferlen; // TODO: check me
default:
printf("G1CTRL: Unmapped read %08x\n", 0x5f7400+offset*4);
debugger_break(machine());
}
return g1bus_regs[offset];
}
WRITE32_MEMBER(dc_cons_state::dc_mess_g1_ctrl_w )
{
g1bus_regs[offset] = data; // 5f7400+reg*4=dat
// osd_printf_verbose("G1CTRL: [%08x=%x] write %" I64FMT "x to %x, mask %" I64FMT "x\n", 0x5f7400+reg*4, dat, data, offset, mem_mask);
switch (offset)
{
case SB_GDST:
if (data & 1 && g1bus_regs[SB_GDEN] == 1) // 0 -> 1
{
if (g1bus_regs[SB_GDDIR] == 0)
{
printf("G1CTRL: unsupported transfer\n");
return;
}
atapi_xferbase = g1bus_regs[SB_GDSTAR];
//atapi_timer->adjust(m_maincpu->cycles_to_attotime((ATAPI_CYCLES_PER_SECTOR * (atapi_xferlen/2048))));
/* 12x * 75 Hz = 0,00(1) secs per sector */
/* TODO: make DMA to be single step */
atapi_timer->adjust(attotime::from_usec(1111*atapi_xferlen/2048));
// atapi_regs[ATAPI_REG_SAMTAG] = GDROM_PAUSE_STATE | 0x80;
}
break;
case SB_GDLEN:
atapi_xferlen = data;
break;
// The following is required to unlock the GD-ROM. The original Japanese BIOS doesn't need it
case GD_UNLOCK:
if (data==0 || data==0x001fffff || data==0x42fe)
{
// atapi_regs[ATAPI_REG_SAMTAG] = GDROM_PAUSE_STATE | 0x80;
printf("Unlocking GD-ROM! %x\n", data);
}
break;
}
}
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