/*
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/>.
*/

#ifndef PCI_HOST_H
#define PCI_HOST_H

#include <core/bitops.h>
#include <devices/deviceregistry.h>
#include <endianswap.h>

#include <cinttypes>
#include <string>
#include <unordered_map>
#include <vector>

enum {
    PCI_CONFIG_DIRECTION    = 1,
    PCI_CONFIG_READ         = 0,
    PCI_CONFIG_WRITE        = 1,

    PCI_CONFIG_TYPE         = 4,
    PCI_CONFIG_TYPE_0       = 0,
    PCI_CONFIG_TYPE_1       = 4,
};

/** PCI config space access details */
typedef struct AccessDetails {
    uint8_t size;
    uint8_t offset;
    uint8_t flags;
} AccessDetails;

class PCIDevice;    // forward declaration to prevent errors

class PCIHost {
public:
    PCIHost() {
        this->dev_map.clear();
        io_space_devs.clear();
    };
    ~PCIHost() = default;

    virtual bool pci_register_device(int dev_num, PCIDevice* dev_instance);

    virtual bool pci_register_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice* obj);
    virtual bool pci_unregister_mmio_region(uint32_t start_addr, uint32_t size, PCIDevice* obj);

    virtual void attach_pci_device(std::string& dev_name, int slot_id);

    virtual PCIDevice *pci_find_device(uint8_t bus_num, uint8_t dev_num, uint8_t fun_num);

protected:
    std::unordered_map<int, PCIDevice*> dev_map;
    std::vector<PCIDevice*>             io_space_devs;
};

// Helpers for data conversion in the PCI Configuration space.

/**
    Perform size dependent endian swapping for value that is dword from PCI config.

    Unaligned data is handled properly by wrapping around if needed.
 */
inline uint32_t pci_conv_rd_data(uint32_t value, AccessDetails &details) {
    switch (details.size << 2 | details.offset) {
    // Bytes
    case 0x04:
        return value & 0xFF;            // 0
    case 0x05:
        return (value >>  8) & 0xFF;    // 1
    case 0x06:
        return (value >> 16) & 0xFF;    // 2
    case 0x07:
        return (value >> 24) & 0xFF;    // 3

    // Words
    case 0x08:
        return BYTESWAP_16(value);                          // 0 1
    case 0x09:
        return BYTESWAP_16((value >>  8) & 0xFFFFU);        // 1 2
    case 0x0A:
        return BYTESWAP_16((value >> 16) & 0xFFFFU);        // 2 3
    case 0x0B:
        return ((value >> 16) & 0xFF00) | (value & 0xFF);   // 3 0

    // Dwords
    case 0x10:
        return BYTESWAP_32(value);              // 0 1 2 3
    case 0x11:
        return ROTL_32(BYTESWAP_32(value), 8);  // 1 2 3 0
    case 0x12:
        return ROTL_32(BYTESWAP_32(value), 16); // 2 3 0 1
    case 0x13:
        return ROTR_32(BYTESWAP_32(value), 8);  // 3 0 1 2
    default:
        return 0xFFFFFFFFUL;
    }
}

/**
    Perform size dependent endian swapping for v2, then merge v2 with v1 under
    control of a mask generated according with the size parameter.

    Unaligned data is handled properly by wrapping around if needed.
 */
inline uint32_t pci_conv_wr_data(uint32_t v1, uint32_t v2, AccessDetails &details)
{
    switch (details.size << 2 | details.offset) {
    // Bytes
    case 0x04:
        return (v1 & ~0xFF)      |  (v2 & 0xFF);        //  3  2  1 d0
    case 0x05:
        return (v1 & ~0xFF00)    | ((v2 & 0xFF) << 8);  //  3  2 d0  0
    case 0x06:
        return (v1 & ~0xFF0000)  | ((v2 & 0xFF) << 16); //  3 d0  1  0
    case 0x07:
        return (v1 & 0x00FFFFFF) | ((v2 & 0xFF) << 24); // d0  2  1  0

    // Words
    case 0x08:
        return (v1 & ~0xFFFF)    |  BYTESWAP_16(v2);        //  3  2 d1 d0
    case 0x09:
        return (v1 & ~0xFFFF00)  | (BYTESWAP_16(v2) << 8);  //  3 d1 d0  0
    case 0x0a:
        return (v1 & 0x0000FFFF) | (BYTESWAP_16(v2) << 16); // d1 d0  1  0
    case 0x0b:
        return (v1 & 0x00FFFF00) | ((v2 & 0xFF00) << 16) |
               (v2 & 0xFF);                                 // d0  2  1 d1

    // Dwords
    case 0x10:
        return BYTESWAP_32(v2);              // d3 d2 d1 d0
    case 0x11:
        return ROTL_32(BYTESWAP_32(v2), 8);  // d2 d1 d0 d3
    case 0x12:
        return ROTL_32(BYTESWAP_32(v2), 16); // d1 d0 d3 d2
    case 0x13:
        return ROTR_32(BYTESWAP_32(v2), 8);  // d0 d3 d2 d1

    default:
        return 0xFFFFFFFFUL;
    }
}

#endif /* PCI_HOST_H */