/**
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#ifndef PICO_RNG_H_
#define PICO_RNG_H_

#include "usb_common.h"

// Struct in which we keep the endpoint configuration
typedef void (*usb_ep_handler)(uint8_t *buf, uint16_t len);
struct usb_endpoint_configuration {
    const struct usb_endpoint_descriptor *descriptor;
    usb_ep_handler handler;

    // Pointers to endpoint + buffer control registers
    // in the USB controller DPSRAM
    volatile uint32_t *endpoint_control;
    volatile uint32_t *buffer_control;
    volatile uint8_t *data_buffer;

    // Toggle after each packet (unless replying to a SETUP)
    uint8_t next_pid;
};

// Struct in which we keep the device configuration
struct usb_device_configuration {
    const struct usb_device_descriptor *device_descriptor;
    const struct usb_interface_descriptor *interface_descriptor;
    const struct usb_configuration_descriptor *config_descriptor;
    const unsigned char *lang_descriptor;
    const unsigned char **descriptor_strings;
    // USB num endpoints is 16
    struct usb_endpoint_configuration endpoints[USB_NUM_ENDPOINTS];
};

#define EP0_IN_ADDR  (USB_DIR_IN  | 0)
#define EP0_OUT_ADDR (USB_DIR_OUT | 0)
#define EP1_IN_ADDR  (USB_DIR_IN  | 1)

// EP0 IN and OUT
static const struct usb_endpoint_descriptor ep0_out = {
        .bLength          = sizeof(struct usb_endpoint_descriptor),
        .bDescriptorType  = USB_DT_ENDPOINT,
        .bEndpointAddress = EP0_OUT_ADDR, // EP number 0, OUT from host (rx to device)
        .bmAttributes     = USB_TRANSFER_TYPE_CONTROL,
        .wMaxPacketSize   = 64,
        .bInterval        = 0
};

static const struct usb_endpoint_descriptor ep0_in = {
        .bLength          = sizeof(struct usb_endpoint_descriptor),
        .bDescriptorType  = USB_DT_ENDPOINT,
        .bEndpointAddress = EP0_IN_ADDR, // EP number 0, OUT from host (rx to device)
        .bmAttributes     = USB_TRANSFER_TYPE_CONTROL,
        .wMaxPacketSize   = 64,
        .bInterval        = 0
};

// Descriptors
static const struct usb_device_descriptor device_descriptor = {
        .bLength         = sizeof(struct usb_device_descriptor),
        .bDescriptorType = USB_DT_DEVICE,
        .bcdUSB          = 0x0110, // USB 1.1 device
        .bDeviceClass    = 0,      // Specified in interface descriptor
        .bDeviceSubClass = 0,      // No subclass
        .bDeviceProtocol = 0,      // No protocol
        .bMaxPacketSize0 = 64,     // Max packet size for ep0
        .idVendor        = 0x0000, // Your vendor id - Choose an unregistered vendor id
        .idProduct       = 0x0004, // Your product ID
        .bcdDevice       = 0,      // No device revision number
        .iManufacturer   = 1,      // Manufacturer string index
        .iProduct        = 2,      // Product string index
        .iSerialNumber = 0,        // No serial number
        .bNumConfigurations = 1    // One configuration
};

static const struct usb_interface_descriptor interface_descriptor = {
        .bLength            = sizeof(struct usb_interface_descriptor),
        .bDescriptorType    = USB_DT_INTERFACE,
        .bInterfaceNumber   = 0,
        .bAlternateSetting  = 0,
        .bNumEndpoints      = 1,    // Interface has 1 endpoint
        .bInterfaceClass    = 0xef, // Miscellaneous device. See https://www.usb.org/defined-class-codes.
        .bInterfaceSubClass = 0,
        .bInterfaceProtocol = 0,
        .iInterface         = 0
};

static const struct usb_endpoint_descriptor ep1_in = {
        .bLength          = sizeof(struct usb_endpoint_descriptor),
        .bDescriptorType  = USB_DT_ENDPOINT,
        .bEndpointAddress = EP1_IN_ADDR, // EP number 1, IN from host (tx from device)
        .bmAttributes     = USB_TRANSFER_TYPE_BULK,
        .wMaxPacketSize   = 64,
        .bInterval        = 0
};

static const struct usb_configuration_descriptor config_descriptor = {
        .bLength         = sizeof(struct usb_configuration_descriptor),
        .bDescriptorType = USB_DT_CONFIG,
        .wTotalLength    = (sizeof(config_descriptor) +
                            sizeof(interface_descriptor) +
                            sizeof(ep1_in)),
        .bNumInterfaces  = 1,
        .bConfigurationValue = 1, // Configuration 1
        .iConfiguration = 0,      // No string
        .bmAttributes = 0xc0,     // attributes: self powered, no remote wakeup
        .bMaxPower = 0x32         // 100ma
};

static const unsigned char lang_descriptor[] = {
        4,         // bLength
        0x03,      // bDescriptorType == String Descriptor
        0x09, 0x04 // language id = us english
};

static const unsigned char *descriptor_strings[] = {
        "Raspberry Pi",    // Vendor
        "Pico Random Number Generator" // Product
};

#endif
