mirror of
https://github.com/dingusdev/dingusppc.git
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289 lines
7.4 KiB
C++
289 lines
7.4 KiB
C++
/*
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DingusPPC - The Experimental PowerPC Macintosh emulator
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Copyright (C) 2018-23 divingkatae and maximum
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(theweirdo) spatium
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(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/** @file SCSI bus emulation. */
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#include <devices/common/hwcomponent.h>
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#include <devices/common/scsi/scsi.h>
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#include <devices/deviceregistry.h>
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#include <loguru.hpp>
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#include <cinttypes>
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ScsiBus::ScsiBus(const std::string name)
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{
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this->set_name(name);
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supports_types(HWCompType::SCSI_BUS);
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for(int i = 0; i < SCSI_MAX_DEVS; i++) {
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this->devices[i] = nullptr;
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this->dev_ctrl_lines[i] = 0;
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}
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this->ctrl_lines = 0; // all control lines released
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this->data_lines = 0; // data lines released
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this->arb_winner_id = -1;
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this->initiator_id = -1;
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this->target_id = -1;
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}
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void ScsiBus::register_device(int id, ScsiDevice* dev_obj)
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{
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if (this->devices[id] != nullptr) {
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ABORT_F("ScsiBus: device with ID %d already registered", id);
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}
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this->devices[id] = dev_obj;
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}
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void ScsiBus::change_bus_phase(int initiator_id)
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{
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for (int i = 0; i < SCSI_MAX_DEVS; i++) {
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if (i == initiator_id)
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continue; // don't notify the initiator
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if (this->devices[i] != nullptr) {
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this->devices[i]->notify(this, ScsiMsg::BUS_PHASE_CHANGE, this->cur_phase);
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}
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}
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}
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void ScsiBus::assert_ctrl_line(int initiator_id, uint16_t mask)
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{
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uint16_t new_state = 0xFFFFU & mask;
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this->dev_ctrl_lines[initiator_id] |= new_state;
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if (new_state == this->ctrl_lines) {
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return;
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}
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if (new_state & SCSI_CTRL_RST) {
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this->ctrl_lines |= SCSI_CTRL_RST;
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this->cur_phase = ScsiPhase::RESET;
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change_bus_phase(initiator_id);
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}
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}
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void ScsiBus::release_ctrl_line(int id, uint16_t mask)
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{
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uint16_t new_state = 0;
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this->dev_ctrl_lines[id] &= ~mask;
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// OR control lines of all devices together
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for (int i = 0; i < SCSI_MAX_DEVS; i++) {
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new_state |= this->dev_ctrl_lines[i];
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}
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if (this->ctrl_lines & SCSI_CTRL_RST) {
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if (!(new_state & SCSI_CTRL_RST)) {
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this->ctrl_lines = new_state;
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this->cur_phase = ScsiPhase::BUS_FREE;
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change_bus_phase(id);
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}
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} else {
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this->ctrl_lines = new_state;
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}
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}
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void ScsiBus::release_ctrl_lines(int id)
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{
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this->release_ctrl_line(id, 0xFFFFUL);
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}
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uint16_t ScsiBus::test_ctrl_lines(uint16_t mask)
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{
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uint16_t new_state = 0;
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// OR control lines of all devices together
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for (int i = 0; i < SCSI_MAX_DEVS; i++) {
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new_state |= this->dev_ctrl_lines[i];
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}
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return new_state & mask;
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}
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int ScsiBus::switch_phase(int id, int new_phase)
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{
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int old_phase = this->cur_phase;
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// leave the current phase (low-level)
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switch (old_phase) {
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case ScsiPhase::COMMAND:
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this->release_ctrl_line(id, SCSI_CTRL_CD);
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break;
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case ScsiPhase::DATA_IN:
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this->release_ctrl_line(id, SCSI_CTRL_IO);
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break;
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case ScsiPhase::STATUS:
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this->release_ctrl_line(id, SCSI_CTRL_CD | SCSI_CTRL_IO);
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break;
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case ScsiPhase::MESSAGE_OUT:
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this->release_ctrl_line(id, SCSI_CTRL_CD | SCSI_CTRL_MSG);
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break;
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}
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// enter new phase (low-level)
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switch (new_phase) {
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case ScsiPhase::COMMAND:
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this->assert_ctrl_line(id, SCSI_CTRL_CD);
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break;
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case ScsiPhase::DATA_IN:
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this->assert_ctrl_line(id, SCSI_CTRL_IO);
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break;
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case ScsiPhase::STATUS:
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this->assert_ctrl_line(id, SCSI_CTRL_CD | SCSI_CTRL_IO);
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break;
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case ScsiPhase::MESSAGE_OUT:
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this->assert_ctrl_line(id, SCSI_CTRL_CD | SCSI_CTRL_MSG);
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break;
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}
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// switch the bus to the new phase (high-level)
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this->cur_phase = new_phase;
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change_bus_phase(id);
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return old_phase;
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}
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bool ScsiBus::begin_arbitration(int initiator_id)
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{
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if (this->cur_phase == ScsiPhase::BUS_FREE) {
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this->data_lines |= 1 << initiator_id;
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this->cur_phase = ScsiPhase::ARBITRATION;
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change_bus_phase(initiator_id);
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return true;
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} else {
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return false;
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}
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}
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bool ScsiBus::end_arbitration(int initiator_id)
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{
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int highest_id = -1;
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// find the highest ID bit on the data lines
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for (int id = 7; id >= 0; id--) {
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if (this->data_lines & (1 << id)) {
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highest_id = id;
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break;
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}
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}
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if (highest_id >= 0) {
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this->arb_winner_id = highest_id;
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}
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return highest_id == initiator_id;
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}
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bool ScsiBus::begin_selection(int initiator_id, int target_id, bool atn)
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{
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// perform bus integrity checks
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if (this->cur_phase != ScsiPhase::ARBITRATION || this->arb_winner_id != initiator_id)
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return false;
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this->assert_ctrl_line(initiator_id, SCSI_CTRL_SEL);
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this->data_lines = (1 << initiator_id) | (1 << target_id);
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if (atn) {
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assert_ctrl_line(initiator_id, SCSI_CTRL_ATN);
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}
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this->initiator_id = initiator_id;
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this->cur_phase = ScsiPhase::SELECTION;
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change_bus_phase(initiator_id);
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return true;
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}
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void ScsiBus::confirm_selection(int target_id)
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{
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this->target_id = target_id;
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// notify initiator about selection confirmation from target
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if (this->initiator_id >= 0) {
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this->devices[this->initiator_id]->notify(this, ScsiMsg::CONFIRM_SEL, target_id);
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}
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}
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bool ScsiBus::end_selection(int initiator_id, int target_id)
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{
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// check for selection confirmation from target
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return this->target_id == target_id;
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}
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bool ScsiBus::pull_data(const int id, uint8_t* dst_ptr, const int size)
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{
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if (dst_ptr == nullptr || !size) {
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return false;
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}
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if (!this->devices[id]->send_data(dst_ptr, size)) {
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LOG_F(ERROR, "ScsiBus: error while transferring T->I data!");
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return false;
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}
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return true;
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}
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bool ScsiBus::push_data(const int id, const uint8_t* src_ptr, const int size)
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{
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if (!this->devices[id]->rcv_data(src_ptr, size)) {
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LOG_F(ERROR, "ScsiBus: error while transferring I->T data!");
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return false;
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}
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return true;
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}
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void ScsiBus::target_next_step()
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{
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this->devices[this->target_id]->next_step(this);
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}
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bool ScsiBus::negotiate_xfer(int& bytes_in, int& bytes_out)
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{
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this->devices[this->target_id]->prepare_xfer(this, bytes_in, bytes_out);
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return true;
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}
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void ScsiBus::disconnect(int dev_id)
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{
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this->release_ctrl_lines(dev_id);
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if (!(this->ctrl_lines & SCSI_CTRL_BSY) && !(this->ctrl_lines & SCSI_CTRL_SEL)) {
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this->cur_phase = ScsiPhase::BUS_FREE;
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change_bus_phase(dev_id);
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}
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}
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static const DeviceDescription Scsi0_Descriptor = {
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ScsiBus::create_first, {}, {}
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};
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static const DeviceDescription Scsi1_Descriptor = {
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ScsiBus::create_second, {}, {}
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};
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REGISTER_DEVICE(Scsi0, Scsi0_Descriptor);
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REGISTER_DEVICE(Scsi1, Scsi1_Descriptor);
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