dingusppc/devices/common/scsi/scsi.h
2022-02-06 01:50:54 +01:00

124 lines
3.2 KiB
C++

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