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dingusppc/devices/common/scsi/sc53c94.cpp

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/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-24 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 NCR53C94/Am53CF94 SCSI controller emulation. */
#include <core/timermanager.h>
#include <devices/common/dmacore.h>
#include <devices/common/hwcomponent.h>
#include <devices/common/hwinterrupt.h>
#include <devices/common/scsi/sc53c94.h>
#include <devices/deviceregistry.h>
#include <loguru.hpp>
#include <machines/machinebase.h>
#include <cinttypes>
#include <cstring>
Sc53C94::Sc53C94(uint8_t chip_id, uint8_t my_id) : ScsiDevice("SC53C94", my_id)
{
this->chip_id = chip_id;
this->my_bus_id = my_id;
supports_types(HWCompType::SCSI_HOST | HWCompType::SCSI_DEV);
reset_device();
}
int Sc53C94::device_postinit()
{
this->bus_obj = dynamic_cast<ScsiBus*>(gMachineObj->get_comp_by_name("ScsiCurio"));
if (this->bus_obj) {
this->bus_obj->register_device(7, static_cast<ScsiDevice*>(this));
this->bus_obj->attach_scsi_devices("");
}
this->int_ctrl = dynamic_cast<InterruptCtrl*>(
gMachineObj->get_comp_by_type(HWCompType::INT_CTRL));
this->irq_id = this->int_ctrl->register_dev_int(IntSrc::SCSI_CURIO);
return 0;
}
void Sc53C94::reset_device()
{
// part-unique ID to be read using a magic sequence
this->set_xfer_count = this->chip_id << 16;
this->clk_factor = 2;
this->sel_timeout = 0;
this->is_initiator = true;
// clear command FIFO
this->cmd_fifo_pos = 0;
// clear data FIFO
this->data_fifo_pos = 0;
this->data_fifo[0] = 0;
this->seq_step = 0;
this->status = 0;
}
uint8_t Sc53C94::read(uint8_t reg_offset)
{
uint8_t status, int_status;
switch (reg_offset) {
case Read::Reg53C94::Xfer_Cnt_LSB:
return this->xfer_count & 0xFFU;
case Read::Reg53C94::Xfer_Cnt_MSB:
return (this->xfer_count >> 8) & 0xFFU;
case Read::Reg53C94::FIFO:
return this->fifo_pop();
case Read::Reg53C94::Command:
return this->cmd_fifo[0];
case Read::Reg53C94::Status:
status = bus_obj->test_ctrl_lines(SCSI_CTRL_MSG | SCSI_CTRL_CD | SCSI_CTRL_IO);
return (this->status & 0xF8) | status;
case Read::Reg53C94::Int_Status:
int_status = this->int_status;
this->seq_step = 0;
this->int_status = 0;
this->update_irq();
return int_status;
case Read::Reg53C94::Seq_Step:
return this->seq_step;
case Read::Reg53C94::FIFO_Flags:
return (this->seq_step << 5) | (this->data_fifo_pos & 0x1F);
case Read::Reg53C94::Config_1:
return this->config1;
case Read::Reg53C94::Config_3:
return this->config3;
case Read::Reg53C94::Xfer_Cnt_Hi:
if (this->config2 & CFG2_ENF) {
return (this->xfer_count >> 16) & 0xFFU;
}
break;
default:
LOG_F(INFO, "%s: reading from register %d", this->name.c_str(), reg_offset);
}
return 0;
}
void Sc53C94::write(uint8_t reg_offset, uint8_t value)
{
switch (reg_offset) {
case Write::Reg53C94::Xfer_Cnt_LSB:
this->set_xfer_count = (this->set_xfer_count & ~0xFFU) | value;
break;
case Write::Reg53C94::Xfer_Cnt_MSB:
this->set_xfer_count = (this->set_xfer_count & ~0xFF00U) | (value << 8);
break;
case Write::Reg53C94::Command:
update_command_reg(value);
break;
case Write::Reg53C94::FIFO:
fifo_push(value);
break;
case Write::Reg53C94::Dest_Bus_ID:
this->target_id = value & 7;
break;
case Write::Reg53C94::Sel_Timeout:
this->sel_timeout = value;
break;
case Write::Reg53C94::Sync_Offset:
this->sync_offset = value;
break;
case Write::Reg53C94::Clock_Factor:
this->clk_factor = value;
break;
case Write::Reg53C94::Config_1:
if ((value & 7) != this->my_bus_id) {
ABORT_F("%s: HBA bus ID mismatch!", this->name.c_str());
}
this->config1 = value;
break;
case Write::Reg53C94::Config_2:
this->config2 = value;
break;
case Write::Reg53C94::Config_3:
this->config3 = value;
break;
default:
LOG_F(INFO, "%s: writing 0x%X to %d register", this->name.c_str(), value,
reg_offset);
}
}
uint16_t Sc53C94::pseudo_dma_read()
{
uint16_t data_word;
bool is_done = false;
if (this->data_fifo_pos >= 2) {
// remove one word from FIFO
data_word = (this->data_fifo[0] << 8) | this->data_fifo[1];
this->data_fifo_pos -= 2;
std:memmove(this->data_fifo, &this->data_fifo[2], this->data_fifo_pos);
// update DMA status
if (this->is_dma_cmd) {
this->xfer_count -= 2;
if (!this->xfer_count) {
is_done = true;
this->status |= STAT_TC; // signal zero transfer count
this->cur_state = SeqState::XFER_END;
this->sequencer();
}
}
}
else {
LOG_F(ERROR, "SC53C94: FIFO underrun %d", data_fifo_pos);
data_word = 0;
}
// see if we need to refill FIFO
if (!this->data_fifo_pos && !is_done) {
this->sequencer();
}
return data_word;
}
void Sc53C94::pseudo_dma_write(uint16_t data) {
this->fifo_push((data >> 8) & 0xFFU);
this->fifo_push(data & 0xFFU);
// update DMA status
if (this->is_dma_cmd) {
this->xfer_count -= 2;
if (!this->xfer_count) {
this->status |= STAT_TC; // signal zero transfer count
//this->cur_state = SeqState::XFER_END;
this->sequencer();
}
}
}
void Sc53C94::update_command_reg(uint8_t cmd)
{
if (this->on_reset && (cmd & 0x7F) != CMD_NOP) {
LOG_F(WARNING, "%s: command register blocked after RESET!", this->name.c_str());
return;
}
// NOTE: Reset Device (chip), Reset Bus and DMA Stop commands execute
// immediately while all others are placed into the command FIFO
switch (cmd & 0x7F) {
case CMD_RESET_DEVICE:
case CMD_RESET_BUS:
case CMD_DMA_STOP:
this->cmd_fifo_pos = 0; // put them at the bottom of the command FIFO
}
if (this->cmd_fifo_pos < 2) {
// put new command into the command FIFO
this->cmd_fifo[this->cmd_fifo_pos++] = cmd;
if (this->cmd_fifo_pos == 1) {
exec_command();
}
} else {
LOG_F(ERROR, "%s: the top of the command FIFO overwritten!", this->name.c_str());
this->status |= STAT_GE; // signal IOE/Gross Error
}
}
void Sc53C94::exec_command()
{
uint8_t cmd = this->cur_cmd = this->cmd_fifo[0] & 0x7F;
this->is_dma_cmd = !!(this->cmd_fifo[0] & 0x80);
if (this->is_dma_cmd) {
if (this->config2 & CFG2_ENF) { // extended mode: 24-bit
this->xfer_count = this->set_xfer_count & 0xFFFFFFUL;
} else { // standard mode: 16-bit
this->xfer_count = this->set_xfer_count & 0xFFFFUL;
if (!this->xfer_count) {
this->xfer_count = 65536;
}
}
}
// simple commands will be executed immediately
// complex commands will be broken into multiple steps
// and handled by the sequencer
switch (cmd) {
case CMD_NOP:
this->on_reset = false; // unblock the command register
exec_next_command();
break;
case CMD_CLEAR_FIFO:
this->data_fifo_pos = 0; // set the bottom of the data FIFO to zero
this->data_fifo[0] = 0;
exec_next_command();
break;
case CMD_RESET_DEVICE:
reset_device();
this->on_reset = true; // block the command register
return;
case CMD_RESET_BUS:
LOG_F(INFO, "%s: resetting SCSI bus...", this->name.c_str());
// assert RST line
this->bus_obj->assert_ctrl_line(this->my_bus_id, SCSI_CTRL_RST);
// release RST line after 25 us
my_timer_id = TimerManager::get_instance()->add_oneshot_timer(
USECS_TO_NSECS(25),
[this]() {
this->bus_obj->release_ctrl_line(this->my_bus_id, SCSI_CTRL_RST);
});
if (!(config1 & 0x40)) {
LOG_F(INFO, "%s: reset interrupt issued", this->name.c_str());
this->int_status = INTSTAT_SRST;
}
exec_next_command();
break;
case CMD_XFER:
if (!this->is_initiator) {
// clear command FIFO
this->cmd_fifo_pos = 0;
this->int_status = INTSTAT_ICMD;
this->update_irq();
} else {
this->seq_step = 0;
this->cmd_steps = nullptr;
this->cur_state = SeqState::XFER_BEGIN;
this->sequencer();
}
break;
case CMD_COMPLETE_STEPS:
static SeqDesc * complete_steps_desc = new SeqDesc[3]{
{SeqState::RCV_STATUS, 0, 0},
{SeqState::RCV_MESSAGE, 0, 0},
{SeqState::CMD_COMPLETE, 0, INTSTAT_SR}
};
if (this->bus_obj->current_phase() != ScsiPhase::STATUS) {
ABORT_F("%s: complete steps only works in the STATUS phase", this->name.c_str());
}
this->seq_step = 0;
this->cmd_steps = complete_steps_desc;
this->cur_state = this->cmd_steps->next_step;
this->sequencer();
break;
case CMD_MSG_ACCEPTED:
if (this->is_initiator) {
this->bus_obj->target_next_step();
}
this->bus_obj->release_ctrl_line(this->my_bus_id, SCSI_CTRL_ACK);
this->int_status = INTSTAT_SR;
this->int_status |= INTSTAT_DIS; // TODO: handle target disconnection properly
this->update_irq();
exec_next_command();
break;
case CMD_SELECT_NO_ATN:
static SeqDesc * sel_no_atn_desc = new SeqDesc[3]{
{SeqState::SEL_BEGIN, 0, INTSTAT_DIS },
{SeqState::SEND_CMD, 3, INTSTAT_SR | INTSTAT_SO},
{SeqState::CMD_COMPLETE, 4, INTSTAT_SR | INTSTAT_SO},
};
this->seq_step = 0;
this->cmd_steps = sel_no_atn_desc;
this->cur_state = SeqState::BUS_FREE;
this->sequencer();
LOG_F(9, "%s: SELECT W/O ATN command started", this->name.c_str());
break;
case CMD_SELECT_WITH_ATN:
static SeqDesc * sel_with_atn_desc = new SeqDesc[4]{
{SeqState::SEL_BEGIN, 0, INTSTAT_DIS },
{SeqState::SEND_MSG, 2, INTSTAT_SR | INTSTAT_SO},
{SeqState::SEND_CMD, 3, INTSTAT_SR | INTSTAT_SO},
{SeqState::CMD_COMPLETE, 4, INTSTAT_SR | INTSTAT_SO},
};
this->seq_step = 0;
this->bytes_out = 1; // set message length
this->cmd_steps = sel_with_atn_desc;
this->cur_state = SeqState::BUS_FREE;
this->sequencer();
LOG_F(9, "%s: SELECT WITH ATN command started", this->name.c_str());
break;
case CMD_ENA_SEL_RESEL:
exec_next_command();
break;
default:
LOG_F(ERROR, "%s: invalid/unimplemented command 0x%X", this->name.c_str(), cmd);
this->cmd_fifo_pos--; // remove invalid command from FIFO
this->int_status = INTSTAT_ICMD;
this->update_irq();
}
}
void Sc53C94::exec_next_command()
{
if (this->cmd_fifo_pos) { // skip empty command FIFO
this->cmd_fifo_pos--; // remove completed command
if (this->cmd_fifo_pos) { // is there another command in the FIFO?
this->cmd_fifo[0] = this->cmd_fifo[1]; // top -> bottom
exec_command(); // execute it
}
}
}
void Sc53C94::fifo_push(const uint8_t data)
{
if (this->data_fifo_pos < DATA_FIFO_MAX) {
this->data_fifo[this->data_fifo_pos++] = data;
} else {
LOG_F(ERROR, "%s: data FIFO overflow!", this->name.c_str());
this->status |= STAT_GE; // signal IOE/Gross Error
}
}
uint8_t Sc53C94::fifo_pop()
{
uint8_t data = 0;
if (this->data_fifo_pos < 1) {
LOG_F(ERROR, "%s: data FIFO underflow!", this->name.c_str());
this->status |= STAT_GE; // signal IOE/Gross Error
} else {
data = this->data_fifo[0];
this->data_fifo_pos--;
std:memmove(this->data_fifo, &this->data_fifo[1], this->data_fifo_pos);
}
return data;
}
void Sc53C94::seq_defer_state(uint64_t delay_ns)
{
seq_timer_id = TimerManager::get_instance()->add_oneshot_timer(
delay_ns,
[this]() {
// re-enter the sequencer with the state specified in next_state
this->cur_state = this->next_state;
this->sequencer();
});
}
void Sc53C94::sequencer()
{
switch (this->cur_state) {
case SeqState::IDLE:
break;
case SeqState::BUS_FREE:
if (this->bus_obj->current_phase() == ScsiPhase::BUS_FREE) {
this->next_state = SeqState::ARB_BEGIN;
this->seq_defer_state(BUS_FREE_DELAY + BUS_SETTLE_DELAY);
} else { // continue waiting
this->next_state = SeqState::BUS_FREE;
this->seq_defer_state(BUS_FREE_DELAY);
}
break;
case SeqState::ARB_BEGIN:
if (!this->bus_obj->begin_arbitration(this->my_bus_id)) {
LOG_F(ERROR, "%s: arbitration error, bus not free!", this->name.c_str());
this->bus_obj->release_ctrl_lines(this->my_bus_id);
this->next_state = SeqState::BUS_FREE;
this->seq_defer_state(BUS_CLEAR_DELAY);
break;
}
this->next_state = SeqState::ARB_END;
this->seq_defer_state(ARB_DELAY);
break;
case SeqState::ARB_END:
if (this->bus_obj->end_arbitration(this->my_bus_id)) { // arbitration won
this->next_state = this->cmd_steps->next_step;
this->seq_defer_state(BUS_CLEAR_DELAY + BUS_SETTLE_DELAY);
} else { // arbitration lost
LOG_F(INFO, "%s: arbitration lost!", this->name.c_str());
this->bus_obj->release_ctrl_lines(this->my_bus_id);
this->next_state = SeqState::BUS_FREE;
this->seq_defer_state(BUS_CLEAR_DELAY);
}
break;
case SeqState::SEL_BEGIN:
this->is_initiator = true;
this->bus_obj->begin_selection(this->my_bus_id, this->target_id,
this->cur_cmd != CMD_SELECT_NO_ATN);
this->next_state = SeqState::SEL_END;
this->seq_defer_state(SEL_TIME_OUT);
break;
case SeqState::SEL_END:
if (this->bus_obj->end_selection(this->my_bus_id, this->target_id)) {
this->bus_obj->release_ctrl_line(this->my_bus_id, SCSI_CTRL_SEL);
LOG_F(9, "%s: selection completed", this->name.c_str());
} else { // selection timeout
this->seq_step = this->cmd_steps->step_num;
this->int_status = this->cmd_steps->status;
this->bus_obj->disconnect(this->my_bus_id);
this->cur_state = SeqState::IDLE;
this->update_irq();
exec_next_command();
}
break;
case SeqState::SEND_MSG:
if (this->data_fifo_pos < 1 && this->is_dma_cmd) {
this->drq_cb(1);
this->int_status = INTSTAT_SR;
this->update_irq();
break;
}
this->bus_obj->target_xfer_data();
this->bus_obj->release_ctrl_line(this->my_bus_id, SCSI_CTRL_ATN);
break;
case SeqState::SEND_CMD:
if (this->data_fifo_pos < 1 && this->is_dma_cmd) {
this->drq_cb(1);
this->int_status |= INTSTAT_SR;
this->update_irq();
break;
}
this->bus_obj->target_xfer_data();
break;
case SeqState::CMD_COMPLETE:
this->seq_step = this->cmd_steps->step_num;
this->int_status = this->cmd_steps->status;
this->update_irq();
exec_next_command();
break;
case SeqState::XFER_BEGIN:
this->cur_bus_phase = this->bus_obj->current_phase();
switch (this->cur_bus_phase) {
case ScsiPhase::DATA_OUT:
if (this->is_dma_cmd) {
this->cur_state = SeqState::SEND_DATA;
break;
}
this->bus_obj->push_data(this->target_id, this->data_fifo, this->data_fifo_pos);
this->data_fifo_pos = 0;
this->cur_state = SeqState::XFER_END;
this->sequencer();
break;
case ScsiPhase::DATA_IN:
this->bus_obj->negotiate_xfer(this->data_fifo_pos, this->bytes_out);
this->cur_state = SeqState::RCV_DATA;
this->rcv_data();
if (!(this->is_dma_cmd)) {
this->cur_state = SeqState::XFER_END;
this->sequencer();
}
}
break;
case SeqState::XFER_END:
if (this->is_initiator) {
this->bus_obj->target_next_step();
}
this->int_status = INTSTAT_SR;
this->update_irq();
exec_next_command();
break;
case SeqState::SEND_DATA:
break;
case SeqState::RCV_DATA:
// check for unexpected bus phase changes
if (this->bus_obj->current_phase() != this->cur_bus_phase) {
this->cmd_fifo_pos = 0; // clear command FIFO
this->int_status = INTSTAT_SR;
this->update_irq();
} else {
this->rcv_data();
}
break;
case SeqState::RCV_STATUS:
case SeqState::RCV_MESSAGE:
this->bus_obj->negotiate_xfer(this->data_fifo_pos, this->bytes_out);
this->rcv_data();
if (this->is_initiator) {
if (this->cur_state == SeqState::RCV_STATUS) {
this->bus_obj->target_next_step();
} else if (this->cur_state == SeqState::RCV_MESSAGE) {
this->bus_obj->assert_ctrl_line(this->my_bus_id, SCSI_CTRL_ACK);
this->cmd_steps++;
this->cur_state = this->cmd_steps->next_step;
this->sequencer();
}
}
break;
default:
ABORT_F("%s: unimplemented sequencer state %d", this->name.c_str(), this->cur_state);
}
}
void Sc53C94::update_irq()
{
uint8_t new_irq = !!(this->int_status != 0);
if (new_irq != this->irq) {
this->irq = new_irq;
this->status = (this->status & 0x7F) | (new_irq << 7);
this->int_ctrl->ack_int(this->irq_id, new_irq);
}
}
void Sc53C94::notify(ScsiMsg msg_type, int param)
{
switch (msg_type) {
case ScsiMsg::CONFIRM_SEL:
if (this->target_id == param) {
// cancel selection timeout timer
TimerManager::get_instance()->cancel_timer(this->seq_timer_id);
this->cur_state = SeqState::SEL_END;
this->sequencer();
} else {
LOG_F(WARNING, "%s: ignore invalid selection confirmation message",
this->name.c_str());
}
break;
case ScsiMsg::BUS_PHASE_CHANGE:
this->cur_bus_phase = param;
if (param != ScsiPhase::BUS_FREE && this->cmd_steps != nullptr) {
this->cmd_steps++;
this->cur_state = this->cmd_steps->next_step;
this->sequencer();
}
break;
default:
LOG_F(9, "%s: ignore notification message, type: %d", this->name.c_str(),
msg_type);
}
}
int Sc53C94::send_data(uint8_t* dst_ptr, int count)
{
if (dst_ptr == nullptr || !count) {
return 0;
}
int actual_count = std::min(this->data_fifo_pos, count);
// move data out of the data FIFO
std::memcpy(dst_ptr, this->data_fifo, actual_count);
// remove the just readed data from the data FIFO
this->data_fifo_pos -= actual_count;
if (this->data_fifo_pos > 0) {
std::memmove(this->data_fifo, &this->data_fifo[actual_count], this->data_fifo_pos);
} else if (this->cur_bus_phase == ScsiPhase::DATA_OUT) {
this->cmd_steps++;
this->cur_state = this->cmd_steps->next_step;
this->sequencer();
}
return actual_count;
}
bool Sc53C94::rcv_data()
{
int req_count;
// return if REQ line is negated
if (!this->bus_obj->test_ctrl_lines(SCSI_CTRL_REQ)) {
return false;
}
if (this->is_dma_cmd && this->cur_bus_phase == ScsiPhase::DATA_IN) {
req_count = std::min((int)this->xfer_count, DATA_FIFO_MAX - this->data_fifo_pos);
} else {
req_count = 1;
}
this->bus_obj->pull_data(this->target_id, &this->data_fifo[this->data_fifo_pos], req_count);
this->data_fifo_pos += req_count;
return true;
}
void Sc53C94::real_dma_xfer_out()
{
// transfer data from host's memory to target
while (this->xfer_count) {
uint32_t got_bytes;
uint8_t* src_ptr;
this->dma_ch->pull_data(std::min((int)this->xfer_count, DATA_FIFO_MAX),
&got_bytes, &src_ptr);
std::memcpy(this->data_fifo, src_ptr, got_bytes);
this->data_fifo_pos = got_bytes;
this->bus_obj->push_data(this->target_id, this->data_fifo, this->data_fifo_pos);
this->xfer_count -= this->data_fifo_pos;
this->data_fifo_pos = 0;
if (!this->xfer_count) {
this->status |= STAT_TC; // signal zero transfer count
this->cur_state = SeqState::XFER_END;
this->sequencer();
}
}
}
void Sc53C94::real_dma_xfer_in()
{
bool is_done = false;
// transfer data from target to host's memory
while (this->xfer_count) {
if (this->data_fifo_pos) {
this->dma_ch->push_data((char*)this->data_fifo, this->data_fifo_pos);
this->xfer_count -= this->data_fifo_pos;
this->data_fifo_pos = 0;
if (!this->xfer_count) {
is_done = true;
this->status |= STAT_TC; // signal zero transfer count
this->cur_state = SeqState::XFER_END;
this->sequencer();
}
}
// see if we need to refill FIFO
if (!this->data_fifo_pos && !is_done) {
this->sequencer();
}
}
}
static const PropMap Sc53C94_properties = {
{"hdd_img", new StrProperty("")},
{"cdr_img", new StrProperty("")},
};
static const DeviceDescription Sc53C94_Descriptor = {
Sc53C94::create, {}, Sc53C94_properties
};
REGISTER_DEVICE(Sc53C94, Sc53C94_Descriptor);
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