dingusppc/devices/viacuda.h
2021-10-14 00:01:30 +02:00

172 lines
5.8 KiB
C++

/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-20 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/>.
*/
/** VIA-CUDA combo device emulation.
Author: Max Poliakovski 2019
Versatile interface adapter (VIA) is an old I/O controller that can be found
in nearly every Macintosh computer. In the 68k era, VIA was used to control
various peripherial devices. In a Power Macintosh, its function is limited
to the I/O interface for the Cuda MCU. I therefore decided to put VIA
emulation code here.
Cuda MCU is a multipurpose IC built around a custom version of the Motorola
MC68HC05 microcontroller. It provides several functions including:
- Apple Desktop Bus (ADB) master
- I2C bus master
- Realtime clock (RTC)
- parameter RAM (first generation of the Power Macintosh)
- power management
MC68HC05 doesn't provide any dedicated hardware for serial communication
protocols. All signals required for ADB and I2C will be generated by Cuda
firmware using bit banging (https://en.wikipedia.org/wiki/Bit_banging).
*/
#ifndef VIACUDA_H
#define VIACUDA_H
#include "adb.h"
#include "hwcomponent.h"
#include "i2c.h"
#include "nvram.h"
#include <memory>
/** VIA register offsets. */
enum {
VIA_B = 0x00, /* input/output register B */
VIA_A = 0x01, /* input/output register A */
VIA_DIRB = 0x02, /* direction B */
VIA_DIRA = 0x03, /* direction A */
VIA_T1CL = 0x04, /* low-order timer 1 counter */
VIA_T1CH = 0x05, /* high-order timer 1 counter */
VIA_T1LL = 0x06, /* low-order timer 1 latches */
VIA_T1LH = 0x07, /* high-order timer 1 latches */
VIA_T2CL = 0x08, /* low-order timer 2 latches */
VIA_T2CH = 0x09, /* high-order timer 2 counter */
VIA_SR = 0x0A, /* shift register */
VIA_ACR = 0x0B, /* auxiliary control register */
VIA_PCR = 0x0C, /* periheral control register */
VIA_IFR = 0x0D, /* interrupt flag register */
VIA_IER = 0x0E, /* interrupt enable register */
VIA_ANH = 0x0F, /* input/output register A, no handshake */
};
/** Cuda communication signals. */
enum {
CUDA_TIP = 0x20, /* transaction in progress: 0 - true, 1 - false */
CUDA_BYTEACK = 0x10, /* byte acknowledge: 0 - true, 1 - false */
CUDA_TREQ = 0x08 /* Cuda requests transaction from host */
};
/** Cuda packet types. */
enum {
CUDA_PKT_ADB = 0,
CUDA_PKT_PSEUDO = 1,
CUDA_PKT_ERROR = 2,
CUDA_PKT_TICK = 3,
CUDA_PKT_POWER = 4
};
/** Cuda pseudo commands. */
enum {
CUDA_START_STOP_AUTOPOLL = 0x01, /* start/stop device auto-polling */
CUDA_READ_PRAM = 0x07, /* read parameter RAM */
CUDA_WRITE_PRAM = 0x0C, /* write parameter RAM */
CUDA_SET_AUTOPOLL_RATE = 0x14, /* set auto-polling rate */
CUDA_GET_AUTOPOLL_RATE = 0x16, /* get auto-polling rate */
CUDA_READ_WRITE_I2C = 0x22, /* read/write I2C device */
CUDA_COMB_FMT_I2C = 0x25, /* combined format I2C transaction */
CUDA_OUT_PB0 = 0x26, /* output one bit to Cuda's PB0 line */
};
/** Cuda error codes. */
enum {
CUDA_ERR_BAD_PKT = 1, /* invalid packet type */
CUDA_ERR_BAD_CMD = 2, /* invalid pseudo command */
CUDA_ERR_BAD_SIZE = 3, /* invalid packet size */
CUDA_ERR_BAD_PAR = 4, /* invalid parameter */
CUDA_ERR_I2C = 5 /* invalid I2C data or no acknowledge */
};
class ViaCuda : public HWComponent, public I2CBus {
public:
ViaCuda();
~ViaCuda() = default;
bool supports_type(HWCompType type) {
return (type == HWCompType::ADB_HOST || type == HWCompType::I2C_HOST);
};
uint8_t read(int reg);
void write(int reg, uint8_t value);
private:
uint8_t via_regs[16]; /* VIA virtual registers */
/* Cuda state. */
uint8_t old_tip;
uint8_t old_byteack;
uint8_t treq;
uint8_t in_buf[16];
int32_t in_count;
uint8_t out_buf[16];
int32_t out_count;
int32_t out_pos;
uint8_t poll_rate;
bool is_open_ended;
uint8_t curr_i2c_addr;
uint8_t cur_pram_addr;
void (ViaCuda::*out_handler)(void);
void (ViaCuda::*next_out_handler)(void);
std::unique_ptr<NVram> pram_obj;
ADB_Bus* adb_obj;
void print_enabled_ints(); /* print enabled VIA interrupts and their sources */
void init();
bool ready();
void assert_sr_int();
void write(uint8_t new_state);
void response_header(uint32_t pkt_type, uint32_t pkt_flag);
void error_response(uint32_t error);
void process_packet();
void process_adb_command(uint8_t cmd_byte, int data_count);
void pseudo_command(int cmd, int data_count);
void null_out_handler(void);
void pram_out_handler(void);
void out_buf_handler(void);
void i2c_handler(void);
/* I2C related methods */
void i2c_simple_transaction(uint8_t dev_addr, const uint8_t* in_buf, int in_bytes);
void i2c_comb_transaction(
uint8_t dev_addr, uint8_t sub_addr, uint8_t dev_addr1, const uint8_t* in_buf, int in_bytes);
};
#endif /* VIACUDA_H */