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dingusppc/devices/serial/escc.cpp

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/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-22 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 Enhanced Serial Communications Controller (ESCC) emulation. */
#include <core/timermanager.h>
#include <devices/deviceregistry.h>
#include <devices/serial/chario.h>
#include <devices/serial/escc.h>
#include <loguru.hpp>
#include <machines/machineproperties.h>
#include <cinttypes>
#include <memory>
#include <string>
#include <vector>
/** Remap the compatible addressing scheme to MacRISC one. */
const uint8_t compat_to_macrisc[6] = {
EsccReg::Port_B_Cmd, EsccReg::Port_A_Cmd,
EsccReg::Port_B_Data, EsccReg::Port_A_Data,
EsccReg::Enh_Reg_B, EsccReg::Enh_Reg_A
};
EsccController::EsccController()
{
// allocate channels
this->ch_a = std::unique_ptr<EsccChannel> (new EsccChannel("ESCC_A"));
this->ch_b = std::unique_ptr<EsccChannel> (new EsccChannel("ESCC_B"));
// attach backends
std::string backend_name = GET_STR_PROP("serial_backend");
this->ch_a->attach_backend(
(backend_name == "stdio") ? CHARIO_BE_STDIO :
#ifdef _WIN32
#else
(backend_name == "socket") ? CHARIO_BE_SOCKET :
#endif
CHARIO_BE_NULL
);
this->ch_b->attach_backend(CHARIO_BE_NULL);
this->reg_ptr = 0;
}
void EsccController::reset()
{
this->master_int_cntrl &= 0xFC;
this->master_int_cntrl |= 0xC0;
this->ch_a->reset(true);
this->ch_b->reset(true);
}
uint8_t EsccController::read(uint8_t reg_offset)
{
uint8_t value;
switch(reg_offset) {
case EsccReg::Port_B_Cmd:
LOG_F(9, "ESCC: reading Port B register RR%d", this->reg_ptr);
if (this->reg_ptr == 2) {
// TODO: implement interrupt vector modifications
value = this->int_vec;
} else {
value = this->ch_b->read_reg(this->reg_ptr);
}
this->reg_ptr = 0;
break;
case EsccReg::Port_A_Cmd:
LOG_F(9, "ESCC: reading Port A register RR%d", this->reg_ptr);
if (this->reg_ptr == 2) {
value = this->int_vec;
} else {
value = this->ch_a->read_reg(this->reg_ptr);
}
break;
case EsccReg::Port_B_Data:
value = this->ch_b->receive_byte();
break;
case EsccReg::Port_A_Data:
value = this->ch_a->receive_byte();
break;
case EsccReg::Enh_Reg_B:
LOG_F(WARNING, "ESCC_B: reading from unimplemented register 0x%x", reg_offset);
value = 0;
break;
case EsccReg::Enh_Reg_A:
LOG_F(WARNING, "ESCC_A: reading from unimplemented register 0x%x", reg_offset);
value = 0;
break;
default:
LOG_F(WARNING, "ESCC: reading from unimplemented register 0x%x", reg_offset);
value = 0;
}
return value;
}
void EsccController::write(uint8_t reg_offset, uint8_t value)
{
switch(reg_offset) {
case EsccReg::Port_B_Cmd:
this->write_internal(this->ch_b.get(), value);
break;
case EsccReg::Port_A_Cmd:
this->write_internal(this->ch_a.get(), value);
break;
case EsccReg::Port_B_Data:
this->ch_b->send_byte(value);
break;
case EsccReg::Port_A_Data:
this->ch_a->send_byte(value);
break;
default:
LOG_F(9, "ESCC: writing 0x%X to unimplemented register 0x%x", value, reg_offset);
}
}
void EsccController::write_internal(EsccChannel *ch, uint8_t value)
{
if (this->reg_ptr) {
// chip-specific registers
if (this->reg_ptr == 9) {
// see if some reset is requested
switch(value & 0xC0) {
case RESET_CH_B:
this->master_int_cntrl &= 0xDF;
this->ch_b->reset(false);
break;
case RESET_CH_A:
this->master_int_cntrl &= 0xDF;
this->ch_a->reset(false);
break;
case RESET_ESCC:
this->reset();
break;
}
this->master_int_cntrl = value & 0x3F;
} else if (this->reg_ptr == 2) {
this->int_vec = value;
} else { // channel-specific registers
ch->write_reg(this->reg_ptr, value);
}
this->reg_ptr = 0;
} else {
this->reg_ptr = value & 7;
switch(value >> 3) {
case WR0Cmd::Point_High:
this->reg_ptr |= 8;
break;
}
}
}
// ======================== ESCC Channel methods ==============================
void EsccChannel::attach_backend(int id)
{
switch(id) {
case CHARIO_BE_NULL:
this->chario = std::unique_ptr<CharIoBackEnd> (new CharIoNull);
break;
case CHARIO_BE_STDIO:
this->chario = std::unique_ptr<CharIoBackEnd> (new CharIoStdin);
break;
#ifdef _WIN32
#else
case CHARIO_BE_SOCKET:
this->chario = std::unique_ptr<CharIoBackEnd> (new CharIoSocket);
break;
#endif
default:
LOG_F(ERROR, "%s: unknown backend ID %d, using NULL instead", this->name.c_str(), id);
this->chario = std::unique_ptr<CharIoBackEnd> (new CharIoNull);
}
}
void EsccChannel::reset(bool hw_reset)
{
this->chario->rcv_disable();
this->write_regs[1] &= 0x24;
this->write_regs[3] &= 0xFE;
this->write_regs[4] |= 0x04;
this->write_regs[5] &= 0x61;
this->write_regs[15] = 0xF8;
this->read_regs[0] &= 0x3C;
this->read_regs[0] |= 0x44;
this->read_regs[1] = 0x06;
this->read_regs[3] = 0x00;
this->read_regs[10] = 0x00;
// initialize DPLL
this->dpll_active = 0;
this->dpll_mode = DpllMode::NRZI;
this->dpll_clock_src = 0;
// initialize Baud Rate Generator (BRG)
this->brg_active = 0;
this->brg_clock_src = 0;
if (hw_reset) {
this->write_regs[10] = 0;
this->write_regs[11] = 8;
this->write_regs[14] &= 0xC0;
this->write_regs[14] |= 0x20;
} else {
this->write_regs[10] &= 0x60;
this->write_regs[14] &= 0xC3;
this->write_regs[14] |= 0x20;
}
}
void EsccChannel::write_reg(int reg_num, uint8_t value)
{
switch (reg_num) {
case 3:
if ((this->write_regs[3] ^ value) & 0x10) {
this->write_regs[3] |= 0x10;
this->read_regs[0] |= 0x10; // set SYNC_HUNT flag
LOG_F(9, "%s: Hunt mode entered.", this->name.c_str());
}
if ((this->write_regs[3] ^ value) & 1) {
if (value & 1) {
this->write_regs[3] |= 0x1;
this->chario->rcv_enable();
LOG_F(9, "%s: receiver enabled.", this->name.c_str());
} else {
this->write_regs[3] ^= 0x1;
this->chario->rcv_disable();
LOG_F(9, "%s: receiver disabled.", this->name.c_str());
this->write_regs[3] |= 0x10; // enter HUNT mode
this->read_regs[0] |= 0x10; // set SYNC_HUNT flag
}
}
this->write_regs[3] = (this->write_regs[3] & 0x11) | (value & 0xEE);
return;
case 7:
if (this->write_regs[15] & 1) {
this->wr7_enh = value;
return;
}
break;
case 14:
switch (value >> 5) {
case DPLL_NULL_CMD:
break;
case DPLL_ENTER_SRC_MODE:
this->dpll_active = 1;
this->read_regs[10] &= 0x3F;
break;
case DPLL_DISABLE:
this->dpll_active = 0;
// fallthrough
case DPLL_RST_MISSING_CLK:
this->read_regs[10] &= 0x3F;
break;
case DPLL_SET_SRC_BGR:
this->dpll_clock_src = 0;
break;
case DPLL_SET_SRC_RTXC:
this->dpll_clock_src = 1;
break;
case DPLL_SET_FM_MODE:
this->dpll_mode = DpllMode::FM;
break;
case DPLL_SET_NRZI_MODE:
this->dpll_mode = DpllMode::NRZI;
break;
default:
LOG_F(WARNING, "%s: unimplemented DPLL command %d", this->name.c_str(), value >> 5);
}
if (value & 0x1C) { // Local Loopback, Auto Echo DTR/REQ bits set
LOG_F(WARNING, "%s: unexpected value in WR14 = 0x%X", this->name.c_str(), value);
}
if (this->brg_active ^ (value & 1)) {
this->brg_active = value & 1;
LOG_F(9, "%s: BRG %s", this->name.c_str(), this->brg_active ? "enabled" : "disabled");
}
return;
}
this->write_regs[reg_num] = value;
}
uint8_t EsccChannel::read_reg(int reg_num)
{
if (!reg_num) {
if (this->chario->rcv_char_available()) {
this->read_regs[0] |= 1;
}
}
return this->read_regs[reg_num];
}
void EsccChannel::send_byte(uint8_t value)
{
// TODO: put one byte into the Data FIFO
this->chario->xmit_char(value);
}
uint8_t EsccChannel::receive_byte()
{
// TODO: remove one byte from the Receive FIFO
uint8_t c;
if (this->chario->rcv_char_available_now()) {
this->chario->rcv_char(&c);
} else {
c = 0;
}
this->read_regs[0] &= ~1;
return c;
}
void EsccChannel::dma_start_tx()
{
}
void EsccChannel::dma_start_rx()
{
}
void EsccChannel::dma_stop_tx()
{
if (this->timer_id_tx) {
TimerManager::get_instance()->cancel_timer(this->timer_id_tx);
this->timer_id_tx = 0;
}
}
void EsccChannel::dma_stop_rx()
{
if (this->timer_id_rx) {
TimerManager::get_instance()->cancel_timer(this->timer_id_rx);
this->timer_id_rx = 0;
}
}
void EsccChannel::dma_in_tx()
{
LOG_F(ERROR, "%s: Unexpected DMA INPUT command for transmit.", this->name.c_str());
}
void EsccChannel::dma_in_rx()
{
if (dma_ch[1]->get_push_data_remaining()) {
this->timer_id_rx = TimerManager::get_instance()->add_oneshot_timer(
0,
[this]() {
this->timer_id_rx = 0;
char c = receive_byte();
int xx = dma_ch[1]->push_data(&c, 1);
this->dma_in_rx();
});
}
}
void EsccChannel::dma_out_tx()
{
this->timer_id_tx = TimerManager::get_instance()->add_oneshot_timer(
10,
[this]() {
this->timer_id_tx = 0;
uint8_t *data;
uint32_t avail_len;
if (dma_ch[1]->pull_data(256, &avail_len, &data) == MoreData) {
while(avail_len) {
this->send_byte(*data++);
avail_len--;
}
this->dma_out_tx();
}
});
}
void EsccChannel::dma_out_rx()
{
LOG_F(ERROR, "%s: Unexpected DMA OUTPUT command for receive.", this->name.c_str());
}
void EsccChannel::dma_flush_tx()
{
this->dma_stop_tx();
this->timer_id_tx = TimerManager::get_instance()->add_oneshot_timer(
10,
[this]() {
this->timer_id_tx = 0;
dma_ch[1]->end_pull_data();
});
}
void EsccChannel::dma_flush_rx()
{
this->dma_stop_rx();
this->timer_id_rx = TimerManager::get_instance()->add_oneshot_timer(
10,
[this]() {
this->timer_id_rx = 0;
dma_ch[1]->end_push_data();
});
}
static const vector<string> CharIoBackends = {"null", "stdio", "socket"};
static const PropMap Escc_Properties = {
{"serial_backend", new StrProperty("null", CharIoBackends)},
};
static const DeviceDescription Escc_Descriptor = {
EsccController::create, {}, Escc_Properties
};
REGISTER_DEVICE(Escc, Escc_Descriptor);
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