mirror of
https://github.com/dingusdev/dingusppc.git
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124 lines
3.2 KiB
C++
124 lines
3.2 KiB
C++
/*
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DingusPPC - The Experimental PowerPC Macintosh emulator
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Copyright (C) 2018-22 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 definitions. */
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#ifndef SCSI_H
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#define SCSI_H
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#include <devices/common/hwcomponent.h>
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#include <array>
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#include <cinttypes>
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#include <string>
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/** SCSI control signals.
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Bit positions follow the MESH controller convention for easier mapping.
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*/
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enum {
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SCSI_CTRL_IO = 1 << 0,
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SCSI_CTRL_CD = 1 << 1,
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SCSI_CTRL_MSG = 1 << 2,
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SCSI_CTRL_ATN = 1 << 3,
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SCSI_CTRL_ACK = 1 << 4,
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SCSI_CTRL_REQ = 1 << 5,
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SCSI_CTRL_SEL = 1 << 6,
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SCSI_CTRL_BSY = 1 << 7,
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SCSI_CTRL_RST = 1 << 8,
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};
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enum ScsiPhase : int {
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BUS_FREE = 0,
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ARBITRATION,
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SELECTION,
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RESELECTION,
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RESET,
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};
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enum ScsiMsg : int {
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CONFIRM_SEL = 1,
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BUS_PHASE_CHANGE,
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};
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/** Standard SCSI bus timing values measured in ns. */
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#define BUS_SETTLE_DELAY 400
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#define BUS_FREE_DELAY 800
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#define BUS_CLEAR_DELAY 800
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#define ARB_DELAY 2400
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#define SEL_ABORT_TIME 200000
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#define SEL_TIME_OUT 250000000
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#define SCSI_MAX_DEVS 8
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class ScsiDevice : public HWComponent {
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public:
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ScsiDevice() = default;
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~ScsiDevice() = default;
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virtual void notify(ScsiMsg msg_type, int param) = 0;
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private:
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int scsi_id;
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};
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/** This class provides a higher level abstraction for the SCSI bus. */
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class ScsiBus : public HWComponent {
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public:
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ScsiBus();
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~ScsiBus() = default;
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// low-level control/status
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void register_device(int id, ScsiDevice* dev_obj);
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void assert_ctrl_line(int id, uint16_t mask);
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void release_ctrl_line(int id, uint16_t mask);
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void release_ctrl_lines(int id);
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int current_phase() { return this->cur_phase; };
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// high-level control/status
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bool begin_arbitration(int id);
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bool end_arbitration(int id);
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bool begin_selection(int initiator_id, int target_id, bool atn);
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void confirm_selection(int target_id);
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bool end_selection(int initiator_id, int target_id);
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void disconnect(int dev_id);
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protected:
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void change_bus_phase(int initiator_id);
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private:
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std::string name;
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// SCSI devices registered with this bus
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std::array<ScsiDevice*, SCSI_MAX_DEVS> devices;
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// per-device state of the control lines
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uint16_t dev_ctrl_lines[SCSI_MAX_DEVS];
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uint16_t ctrl_lines;
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int cur_phase;
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int arb_winner_id;
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int initiator_id;
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int target_id;
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uint8_t data_lines;
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};
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#endif // SCSI_H
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