dingusppc/devices/common/scsi/sc53c94.h
2022-02-06 01:50:54 +01:00

192 lines
4.9 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 NCR53C94/Am53CF94 SCSI controller definitions. */
/* NOTE: Power Macintosh computers don't have a real NCR 53C94 chip.
The corresponding functionality is provided by the 53CF94 compatible
cell in the custom Curio IC (Am79C950).
*/
#ifndef SC_53C94_H
#define SC_53C94_H
#include "scsi.h"
#include "devices/common/hwinterrupt.h"
#include <cinttypes>
/** 53C94 read registers */
namespace Read {
enum Reg53C94 : uint8_t {
Xfer_Cnt_LSB = 0,
Xfer_Cnt_MSB = 1,
FIFO = 2,
Command = 3,
Status = 4,
Int_Status = 5,
Seq_Step = 6,
FIFO_Flags = 7,
Config_1 = 8,
Config_2 = 0xB,
Config_3 = 0xC,
Config_4 = 0xD, // Am53CF94 extension
Xfer_Cnt_Hi = 0xE, // Am53CF94 extension
};
};
/** 53C94 write registers */
namespace Write {
enum Reg53C94 : uint8_t {
Xfer_Cnt_LSB = 0,
Xfer_Cnt_MSB = 1,
FIFO = 2,
Command = 3,
Dest_Bus_ID = 4,
Sel_Timeout = 5,
Sync_Period = 6,
Sync_Offset = 7,
Config_1 = 8,
Clock_Factor = 9,
Test_Mode = 0xA,
Config_2 = 0xB,
Config_3 = 0xC,
Config_4 = 0xD, // Am53CF94 extension
Xfer_Cnt_Hi = 0xE, // Am53CF94 extension
Data_Align = 0xF
};
};
/** NCR53C94/Am53CF94 commands. */
enum {
CMD_NOP = 0,
CMD_CLEAR_FIFO = 1,
CMD_RESET_DEVICE = 2,
CMD_RESET_BUS = 3,
CMD_DMA_STOP = 4,
CMD_SELECT_NO_ATN = 0x41,
CMD_ENA_SEL_RESEL = 0x44,
};
/** Interrupt status register bits. */
enum {
INTSTAT_SRST = 0x80, // bus reset
INTSTAT_ICMD = 0x40, // invalid command
INTSTAT_DIS = 0x20, // disconnected
INTSTAT_SR = 0x10, // service request
INTSTAT_SO = 0x08, // successful operation
INTSTAT_RESEL = 0x04, // reselected
INTSTAT_SELA = 0x02, // selected as a target with attention
INTSTAT_SEL = 0x01, // selected as a target without attention
};
enum {
CFG2_ENF = 0x40, // Am53CF94: enable features (ENF) bit
};
/** Sequencer states. */
namespace SeqState {
enum {
IDLE = 0,
BUS_FREE,
ARB_BEGIN,
ARB_END,
SEL_BEGIN,
SEL_END,
CMD_BEGIN,
CMD_COMPLETE,
};
};
/** Sequence descriptor for sequencer commands. */
typedef struct {
int next_step;
int step_num;
int status;
} SeqDesc;
class Sc53C94 : public ScsiDevice {
public:
Sc53C94(uint8_t chip_id=12, uint8_t my_id=7);
~Sc53C94() = default;
// HWComponent methods
int device_postinit();
// 53C94 registers access
uint8_t read(uint8_t reg_offset);
void write(uint8_t reg_offset, uint8_t value);
// ScsiDevice methods
void notify(ScsiMsg msg_type, int param);
protected:
void reset_device();
void update_command_reg(uint8_t cmd);
void exec_command();
void exec_next_command();
void fifo_push(const uint8_t data);
void sequencer();
void seq_defer_state(uint64_t delay_ns);
void update_irq();
private:
uint8_t chip_id;
uint8_t my_bus_id;
ScsiBus* bus_obj;
uint32_t my_timer_id;
uint8_t cmd_fifo[2];
uint8_t data_fifo[16];
int cmd_fifo_pos;
int data_fifo_pos;
bool on_reset = false;
uint32_t xfer_count;
uint32_t set_xfer_count;
uint8_t status;
uint8_t target_id;
uint8_t int_status;
uint8_t seq_step;
uint8_t sel_timeout;
uint8_t sync_offset;
uint8_t clk_factor;
uint8_t config1;
uint8_t config2;
uint8_t config3;
// sequencer state
uint32_t seq_timer_id;
uint32_t cur_state;
uint32_t next_state;
SeqDesc* cmd_steps;
bool is_initiator;
uint8_t cur_cmd;
// interrupt related stuff
InterruptCtrl* int_ctrl = nullptr;
uint32_t irq_id = 0;
uint8_t irq = 0;
};
#endif // SC_53C94_H