dingusppc/devices/common/machineid.h

/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-23 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/>.
*/

#ifndef MACHINE_ID_H
#define MACHINE_ID_H

#include <devices/common/hwcomponent.h>
#include <devices/common/mmiodevice.h>
#include <devices/ioctrl/macio.h>

#include <cinttypes>
#include <loguru.hpp>
#include <string>

/**
    @file Contains definitions for Power Macintosh machine ID registers.

    The machine ID register is a memory-based register containing hardcoded
    values the system software can read to identify machine/board it's running on.

    Register location and value meaning are board-dependent.
 */

/**
    Machine ID register for Nubus Power Macs.
    It's located at physical address 0x5FFFFFFC and contains four bytes:
      +0 uint16_t signature = 0xA55A
      +1 uint8_t  machine_type (3 - Power Mac)
      +2 uint8_t  model (0x10 = PDM, 0x12 = Carl Sagan, 0x13 = Cold Fusion)
 */
class NubusMacID : public MMIODevice {
public:
    NubusMacID(const uint16_t id) {
        this->name = "Nubus-Machine-id";
        this->id[0] = 0xA5;
        this->id[1] = 0x5A;
        this->id[2] = (id >> 8) & 0xFF;
        this->id[3] = id & 0xFF;
        supports_types(HWCompType::MMIO_DEV);
    };
    ~NubusMacID() = default;

    uint32_t read(uint32_t rgn_start, uint32_t offset, int size) {
        if (size == 4 && offset == 0) {
            return *(uint32_t*)this->id;
        }
        if (size == 1 && offset < 4) {
            return this->id[offset];
        }
        ABORT_F("NubusMacID: invalid read size %d, offset %d!", size, offset);
        return 0;
    };

    /* not writable */
    void write(uint32_t rgn_start, uint32_t offset, uint32_t value, int size) {};

private:
    uint8_t id[4];
};

/**
    TNT-style machines and derivatives provide two board registers
    telling whether some particular piece of HW is installed or not.
    Both board registers are attached to the IOBus of the I/O controller.
    See machines/machinetnt.cpp for further details.
 **/
class BoardRegister : public HWComponent, public IobusDevice {
public:
    BoardRegister(std::string name, const uint16_t data) {
        this->set_name(name);
        supports_types(HWCompType::IOBUS_DEV);
        this->data = data;
    };
    ~BoardRegister() = default;

    uint16_t iodev_read(uint32_t address) {
        return this->data;
    };

    // appears read-only to guest
    void iodev_write(uint32_t address, uint16_t value) {};

    void update_bits(const uint16_t val, const uint16_t mask) {
        this->data = (this->data & ~mask) | (val & mask);
    };

private:
    uint16_t    data;
};

/**
    The machine ID for the Gossamer board is accesible at 0xFF000004 (phys).
    It contains a 16-bit value revealing machine's capabilities like bus speed,
    ROM speed, I/O configuration etc.
    See machines/machinegossamer.cpp for further details.
 */
class GossamerID : public MMIODevice {
public:
    GossamerID(const uint16_t id) {
        this->id = id;
        this->name = "Machine-id";
        supports_types(HWCompType::MMIO_DEV);
    };
    ~GossamerID() = default;

    uint32_t read(uint32_t rgn_start, uint32_t offset, int size) {
        return ((offset == 4 && size == 2) ? this->id : 0);
    };

    /* not writable */
    void write(uint32_t rgn_start, uint32_t offset, uint32_t value, int size) {};

private:
    uint16_t id;
};

#endif // MACHINE_ID_H