/* Baremetal Risc-V USB <=> Amiga Joystick/Mouse HID converter. 
 * March 2026 - Anders Holck
 * This software has no license. If you choose to use, please include my name :)
*/

#include <stdint.h>
#include "usb_dwc2.h"
#include "pinmux.h"
#include "amiga_hw.h"

void delay(int count) {
    for (volatile int i = 0; i < count; i++);
}

void usb_init_baremetal() {
    // 1. Enable USB Clocks
    uint32_t clk_en = read32(CLK_EN_1);
    clk_en |= (1 << 13) | (1 << 14); 
    write32(CLK_EN_1, clk_en);

    // 2. Power on PHY and release reset
    write32(USB_PHY_CTRL, 0x07);
    delay(10000);

    // 3. Global Reset of DWC2 Core
    write32(GRSTCTL, (1 << 0)); // Soft Reset
    while (!(read32(GRSTCTL) & (1 << 29)));
    delay(10000);
    
    // 4. Force Device Mode and Basic Config
    write32(GUSBCFG, (1 << 30) | (1 << 29)); // Force Device, PHY Interface
    write32(DCFG, 0x0); // Full Speed
    write32(GINTMSK, (1 << 12) | (1 << 13) | (1 << 4) | (1 << 18)); // Reset, Enum, RXFLVL, IEPInt
    
    // 5. Connect
    write32(DCTL, 0); // Clear Soft Disconnect
}

int main() {
    pinmux_init_amiga();
    usb_init_baremetal();

    amiga_input_t input;
    uint8_t hid_report[4] = {0}; // 2 bytes buttons, 2 bytes mouse
    uint32_t report_timer = 0;

    while (1) {
        // 1. Poll Amiga Hardware
        amiga_hw_poll(&input);

        // 2. Poll USB State Machine
        dwc2_poll();

        // 3. Send HID Report every ~10ms (approximate)
        if (++report_timer > 100) {
            report_timer = 0;
            
            // Format HID Report (Match hid_report_desc in usb_descriptors.h)
            // Byte 0: Joy1 (5 bits) + Joy2 (3 bits)
            // Byte 1: Joy2 (remaining 2 bits) + Padding
            // Byte 2: Mouse X
            // Byte 3: Mouse Y
            
            hid_report[0] = input.joy1 | ((input.joy2 & 0x07) << 5);
            hid_report[1] = (input.joy2 >> 3) & 0x03;
            if (input.buttons & 0x01) hid_report[1] |= (1 << 2); // Mouse B1
            if (input.buttons & 0x02) hid_report[1] |= (1 << 3); // Mouse B2
            
            hid_report[2] = (uint8_t)input.mouse_x;
            hid_report[3] = (uint8_t)input.mouse_y;

            // Send via Endpoint 1 (Interrupt IN)
            dwc2_send_packet(1, hid_report, 4);
        }

        delay(100);
    }

    return 0;
}