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// license:BSD-3-Clause
// copyright-holders:smf
/*
* am53cf96.c
*
* AMD/NCR/Symbios 53CF96 SCSI-2 controller.
* Qlogic FAS-236 and Emulex ESP-236 are equivalents
*
* References:
* AMD Am53CF96 manual
*
*/
#include "emu.h"
#include "am53cf96.h"
#include "bus/scsi/scsihle.h"
READ8_MEMBER( am53cf96_device::read )
{
int rv;
static constexpr int states[] = { 0, 0, 1, 1, 2, 3, 4, 5, 6, 7, 0 };
if (offset == REG_STATUS)
{
scsi_regs[REG_STATUS] &= ~0x7;
scsi_regs[REG_STATUS] |= states[xfer_state];
if (xfer_state < 10)
{
xfer_state++;
}
}
rv = scsi_regs[offset];
if (offset == REG_FIFO)
{
// logerror("53cf96: read FIFO %s\n", machine().describe_context());
return 0;
}
// logerror("53cf96: read reg %d = %x %s\n", reg, rv>>shift, machine().describe_context());
if (offset == REG_IRQSTATE)
{
scsi_regs[REG_STATUS] &= ~0x80; // clear IRQ flag
}
return rv;
}
void am53cf96_device::device_timer(emu_timer &timer, device_timer_id tid, int param, void *ptr)
{
scsi_regs[REG_IRQSTATE] = 8; // indicate success
scsi_regs[REG_STATUS] |= 0x80; // indicate IRQ
m_irq_handler(1);
}
WRITE8_MEMBER( am53cf96_device::write )
{
// logerror("53cf96: w %x to reg %d %s\n", data, offset, machine().describe_context());
// if writing to the target ID, cache it off for later
if (offset == REG_STATUS)
{
last_id = data;
}
if (offset == REG_XFERCNTLOW || offset == REG_XFERCNTMID || offset == REG_XFERCNTHI)
{
scsi_regs[REG_STATUS] &= ~0x10; // clear CTZ bit
}
// FIFO
if (offset == REG_FIFO)
{
// osd_printf_debug("%02x to FIFO @ %02d\n", data, fptr);
fifo[fptr++] = data;
if (fptr > 15)
{
fptr = 15;
}
}
// command
if (offset == REG_COMMAND)
{
//dma = (data & 0x80) ? 1 : 0;
fptr = 0;
switch (data & 0x7f)
{
case 0: // NOP
scsi_regs[REG_IRQSTATE] = 8; // indicate success
xfer_state = 0;
break;
case 2: // reset am53cf96
scsi_regs[REG_IRQSTATE] = 8; // indicate success
logerror("53cf96: reset target ID = %d %s\n", last_id, machine().describe_context());
xfer_state = 0;
break;
case 3: // reset SCSI bus
scsi_regs[REG_INTSTATE] = 4; // command sent OK
reset_bus();
xfer_state = 0;
m_transfer_timer->adjust( attotime::from_hz( 16384 ) );
break;
case 0x42: // select with ATN steps
m_transfer_timer->adjust( attotime::from_hz( 16384 ) );
if ((fifo[1] == 0) || (fifo[1] == 0x48) || (fifo[1] == 0x4b))
{
scsi_regs[REG_INTSTATE] = 6;
}
else
{
scsi_regs[REG_INTSTATE] = 4;
}
logerror("53cf96: command %x exec. target ID = %d %s\n", fifo[1], last_id, machine().describe_context());
select(last_id);
send_command(&fifo[1], 12);
xfer_state = 0;
break;
case 0x44: // enable selection/reselection
xfer_state = 0;
break;
case 0x10: // information transfer (must not change xfer_state)
case 0x11: // second phase of information transfer
case 0x12: // message accepted
m_transfer_timer->adjust( attotime::from_hz( 16384 ) );
scsi_regs[REG_INTSTATE] = 6; // command sent OK
break;
default:
printf( "unsupported command %02x\n", data );
break;
}
}
// only update the register mirror if it's not a write-only reg
if (offset != REG_STATUS && offset != REG_INTSTATE && offset != REG_IRQSTATE && offset != REG_FIFOSTATE)
{
scsi_regs[offset] = data;
}
}
am53cf96_device::am53cf96_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
legacy_scsi_host_adapter(mconfig, AM53CF96, tag, owner, clock),
m_irq_handler(*this)
{
}
void am53cf96_device::device_start()
{
legacy_scsi_host_adapter::device_start();
m_irq_handler.resolve_safe();
memset(scsi_regs, 0, sizeof(scsi_regs));
fptr = 0;
xfer_state = 0;
last_id = -1;
save_item( NAME( scsi_regs ) );
save_item( NAME( fifo ) );
save_item( NAME( fptr ) );
save_item( NAME( xfer_state ) );
save_item( NAME( last_id ) );
m_transfer_timer = timer_alloc( TIMER_TRANSFER );
}
// retrieve data from the SCSI controller
void am53cf96_device::dma_read_data(int bytes, uint8_t *pData)
{
scsi_regs[REG_STATUS] |= 0x10; // indicate DMA finished
read_data(pData, bytes);
}
// write data to the SCSI controller
void am53cf96_device::dma_write_data(int bytes, uint8_t *pData)
{
// int i;
scsi_regs[REG_STATUS] |= 0x10; // indicate DMA finished
write_data(pData, bytes);
}
DEFINE_DEVICE_TYPE(AM53CF96, am53cf96_device, "am53cf96", "AMD 53CF96 SCSI")
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