dingusppc/devices/dbdma.cpp
2020-03-19 15:09:24 +01:00

221 lines
6.3 KiB
C++

/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-20 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
/** @file Descriptor-based direct memory access emulation. */
#include <cinttypes>
#include <thirdparty/loguru.hpp>
#include "dbdma.h"
#include "endianswap.h"
#include "cpu/ppc/ppcmmu.h"
void DMAChannel::get_next_cmd(uint32_t cmd_addr, DMACmd *p_cmd)
{
/* load DMACmd from physical memory */
memcpy((uint8_t *)p_cmd, mmu_get_dma_mem(cmd_addr, 16), 16);
}
uint8_t DMAChannel::interpret_cmd()
{
DMACmd cmd_struct;
get_next_cmd(this->cmd_ptr, &cmd_struct);
this->ch_stat &= ~CH_STAT_WAKE; /* clear wake bit (DMA spec, 5.5.3.4) */
switch(cmd_struct.cmd_key >> 4) {
case 0:
LOG_F(INFO, "Executing DMA Command OUTPUT_MORE");
if (cmd_struct.cmd_key & 7) {
LOG_F(ERROR, "Key > 0 not implemented");
break;
}
if (cmd_struct.cmd_bits & 0x3F) {
LOG_F(ERROR, "non-zero i/b/w not implemented");
break;
}
this->dma_cb->dma_push(
mmu_get_dma_mem(cmd_struct.address, cmd_struct.req_count),
cmd_struct.req_count);
this->cmd_ptr += 16;
break;
case 1:
LOG_F(INFO, "Executing DMA Command OUTPUT_LAST");
if (cmd_struct.cmd_key & 7) {
LOG_F(ERROR, "Key > 0 not implemented");
break;
}
if (cmd_struct.cmd_bits & 0x3F) {
LOG_F(ERROR, "non-zero i/b/w not implemented");
break;
}
this->dma_cb->dma_push(
mmu_get_dma_mem(cmd_struct.address, cmd_struct.req_count),
cmd_struct.req_count);
this->cmd_ptr += 16;
break;
case 2:
LOG_F(ERROR, "Unsupported DMA Command INPUT_MORE");
break;
case 3:
LOG_F(ERROR, "Unsupported DMA Command INPUT_LAST");
break;
case 4:
LOG_F(ERROR, "Unsupported DMA Command STORE_QUAD");
break;
case 5:
LOG_F(ERROR, "Unsupported DMA Command LOAD_QUAD");
break;
case 6:
LOG_F(INFO, "Unsupported DMA Command NOP");
break;
case 7:
LOG_F(INFO, "DMA Command: 7 (STOP)");
this->ch_stat &= ~CH_STAT_ACTIVE;
break;
default:
LOG_F(ERROR, "Unsupported DMA command 0x%X", cmd_struct.cmd_key >> 4);
this->ch_stat |= CH_STAT_DEAD;
this->ch_stat &= ~CH_STAT_ACTIVE;
}
return (cmd_struct.cmd_key >> 4);
}
uint32_t DMAChannel::reg_read(uint32_t offset, int size)
{
uint32_t res = 0;
if (size != 4) {
LOG_F(WARNING, "Unsupported non-DWORD read from DMA channel");
return 0;
}
switch(offset) {
case DMAReg::CH_CTRL:
res = 0; /* ChannelControl reads as 0 (DBDMA spec 5.5.1, table 74) */
break;
case DMAReg::CH_STAT:
res = BYTESWAP_32(this->ch_stat);
break;
default:
LOG_F(WARNING, "Unsupported DMA channel register 0x%X", offset);
}
return res;
}
void DMAChannel::reg_write(uint32_t offset, uint32_t value, int size)
{
uint16_t mask, old_stat, new_stat;
if (size != 4) {
LOG_F(WARNING, "Unsupported non-DWORD write to DMA channel");
return;
}
value = BYTESWAP_32(value);
old_stat = this->ch_stat;
switch(offset) {
case DMAReg::CH_CTRL:
mask = value >> 16;
new_stat = (value & mask & 0xF0FFU) | (old_stat & ~mask);
LOG_F(INFO, "New ChannelStatus value = 0x%X", new_stat);
if ((new_stat & CH_STAT_RUN) != (old_stat & CH_STAT_RUN)) {
if (new_stat & CH_STAT_RUN) {
new_stat |= CH_STAT_ACTIVE;
this->ch_stat = new_stat;
this->start();
} else {
new_stat &= ~CH_STAT_ACTIVE;
new_stat &= ~CH_STAT_DEAD;
this->ch_stat = new_stat;
this->abort();
}
} else if ((new_stat & CH_STAT_WAKE) != (old_stat & CH_STAT_WAKE)) {
new_stat |= CH_STAT_ACTIVE;
this->ch_stat = new_stat;
this->resume();
} else if ((new_stat & CH_STAT_PAUSE) != (old_stat & CH_STAT_PAUSE)) {
if (new_stat & CH_STAT_PAUSE) {
new_stat &= ~CH_STAT_ACTIVE;
this->ch_stat = new_stat;
this->pause();
}
}
if (new_stat & CH_STAT_FLUSH) {
LOG_F(WARNING, "DMA flush not implemented!");
new_stat &= ~CH_STAT_FLUSH;
this->ch_stat = new_stat;
}
break;
case DMAReg::CH_STAT:
break; /* ingore writes to ChannelStatus */
case DMAReg::CMD_PTR_LO:
if (!(this->ch_stat & CH_STAT_RUN) && !(this->ch_stat & CH_STAT_ACTIVE)) {
this->cmd_ptr = value;
LOG_F(INFO, "CommandPtrLo set to 0x%X", this->cmd_ptr);
}
break;
default:
LOG_F(WARNING, "Unsupported DMA channel register 0x%X", offset);
}
}
void DMAChannel::start()
{
if (this->ch_stat & CH_STAT_PAUSE) {
LOG_F(WARNING, "Cannot start DMA channel, PAUSE bit is set");
return;
}
LOG_F(INFO, "Starting DMA channel, stat = 0x%X", this->ch_stat);
this->dma_cb->dma_start();
while (this->interpret_cmd() != 7) {
}
}
void DMAChannel::resume()
{
if (this->ch_stat & CH_STAT_PAUSE) {
LOG_F(WARNING, "Cannot resume DMA channel, PAUSE bit is set");
return;
}
LOG_F(INFO, "Resuming DMA channel");
}
void DMAChannel::abort()
{
LOG_F(INFO, "Aborting DMA channel");
}
void DMAChannel::pause()
{
LOG_F(INFO, "Pausing DMA channel");
this->dma_cb->dma_end();
}