usb_descriptors.c

/*
 * Licensed under GNU Public License v3
 * Copyright (c) 2022 Thomas Roth <code@stacksmashing.net>
 * Based on:
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 */

#include "tusb.h"

/* A combination of interfaces must have a unique product id, since PC will save device driver after the first plug.
 * Same VID/PID with different interface e.g MSC (first), then CDC (later) will possibly cause system error on PC.
 *
 * Auto ProductID layout's Bitmap:
 *   [MSB]       MIDI | HID | MSC | CDC          [LSB]
 */
#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
#define USB_PID 0x0004
// #define USB_PID           (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
//                            _PID_MAP(MIDI, 3) | _PID_MAP(VENDOR, 4) )

#define USB_VID   0x2B3E
#define USB_BCD   0x2342

//--------------------------------------------------------------------+
// Device Descriptors
//--------------------------------------------------------------------+
tusb_desc_device_t const desc_device =
{
    .bLength            = sizeof(tusb_desc_device_t),
    .bDescriptorType    = TUSB_DESC_DEVICE,
    .bcdUSB             = USB_BCD,

    // Use Interface Association Descriptor (IAD) for CDC
    // As required by USB Specs IAD's subclass must be common class (2) and protocol must be IAD (1)
    .bDeviceClass       = TUSB_CLASS_MISC,
    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,

    .idVendor           = USB_VID,
    .idProduct          = USB_PID,
    .bcdDevice          = 0x0100,

    .iManufacturer      = 0x01,
    .iProduct           = 0x02,
    .iSerialNumber      = 0x03,

    .bNumConfigurations = 0x01
};

// Invoked when received GET DEVICE DESCRIPTOR
// Application return pointer to descriptor
uint8_t const * tud_descriptor_device_cb(void)
{
  return (uint8_t const *) &desc_device;
}

//--------------------------------------------------------------------+
// Configuration Descriptor
//--------------------------------------------------------------------+
enum
{
  ITF_NUM_CDC_0 = 0,
  ITF_NUM_CDC_0_DATA,

  ITF_NUM_PROBE,
    ITF_NUM_CDC_1,
  ITF_NUM_CDC_1_DATA,
//   ITF_NUM_CDC_2_DATA,
  ITF_NUM_TOTAL
};

#define CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + (CFG_TUD_CDC * TUD_CDC_DESC_LEN) + TUD_VENDOR_DESC_LEN)

#define EPNUM_CDC_0_NOTIF   0x81
#define EPNUM_CDC_0_OUT     0x02
#define EPNUM_CDC_0_IN      0x83

  #define EPNUM_CDC_1_NOTIF   0x86
  #define EPNUM_CDC_1_OUT     0x07
  #define EPNUM_CDC_1_IN      0x88

#define EPNUM_PROBE_OUT     0x04
#define EPNUM_PROBE_IN      0x85
//   #define EPNUM_CDC_2_NOTIF   0x85
//   #define EPNUM_CDC_2_OUT     0x06
//   #define EPNUM_CDC_2_IN      0x86

uint8_t const desc_fs_configuration[] =
{
  // Config number, interface count, string index, total length, attribute, power in mA
  TUD_CONFIG_DESCRIPTOR(1, ITF_NUM_TOTAL, 0, CONFIG_TOTAL_LEN, TUSB_DESC_CONFIG_ATT_REMOTE_WAKEUP, 100),

  // 1st CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
  TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_0, 4, EPNUM_CDC_0_NOTIF, 8, EPNUM_CDC_0_OUT, EPNUM_CDC_0_IN, 64),

  // 2nd CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
//   TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_1, 4, EPNUM_CDC_1_NOTIF, 8, EPNUM_CDC_1_OUT, EPNUM_CDC_1_IN, 64),
  // 3rd CDC: Interface number, string index, EP notification address and size, EP data address (out, in) and size.
//   TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_2, 4, EPNUM_CDC_2_NOTIF, 8, EPNUM_CDC_2_OUT, EPNUM_CDC_2_IN, 64),
  // 4th Vendor: Picoprobe interface
  TUD_VENDOR_DESCRIPTOR(ITF_NUM_PROBE, 0, EPNUM_PROBE_OUT, EPNUM_PROBE_IN, 64),
    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC_1, 4, EPNUM_CDC_1_NOTIF, 8, EPNUM_CDC_1_OUT, EPNUM_CDC_1_IN, 64),
};


// Invoked when received GET CONFIGURATION DESCRIPTOR
// Application return pointer to descriptor
// Descriptor contents must exist long enough for transfer to complete
uint8_t const * tud_descriptor_configuration_cb(uint8_t index)
{
  (void) index; // for multiple configurations

  return desc_fs_configuration;
}

//--------------------------------------------------------------------+
// String Descriptors
//--------------------------------------------------------------------+

// array of pointer to string descriptors
char const* string_desc_arr [] =
{
  (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
  "stacksmashing",                     // 1: Manufacturer
  "Tamarin Cable",              // 2: Product
  "31337",                      // 3: Serials, should use chip ID
  // "Tamarin CDC",                 // 4: CDC Interface
};

static uint16_t _desc_str[32];

// Invoked when received GET STRING DESCRIPTOR request
// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
uint16_t const* tud_descriptor_string_cb(uint8_t index, uint16_t langid)
{
  (void) langid;

  uint8_t chr_count;

  if ( index == 0)
  {
    memcpy(&_desc_str[1], string_desc_arr[0], 2);
    chr_count = 1;
  }else
  {
    // Note: the 0xEE index string is a Microsoft OS 1.0 Descriptors.
    // https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/microsoft-defined-usb-descriptors

    if ( !(index < sizeof(string_desc_arr)/sizeof(string_desc_arr[0])) ) return NULL;

    const char* str = string_desc_arr[index];

    // Cap at max char
    chr_count = strlen(str);
    if ( chr_count > 31 ) chr_count = 31;

    // Convert ASCII string into UTF-16
    for(uint8_t i=0; i<chr_count; i++)
    {
      _desc_str[1+i] = str[i];
    }
  }

  // first byte is length (including header), second byte is string type
  _desc_str[0] = (TUSB_DESC_STRING << 8 ) | (2*chr_count + 2);

  return _desc_str;
}