usb_descriptors.c

/* 
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include "tusb.h"
#include "pico/unique_id.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]       NET | VENDOR | MIDI | HID | MSC | CDC          [LSB]
 */
#define _PID_MAP(itf, n)  ( (CFG_TUD_##itf) << (n) )
#define USB_PID           (0x4000 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) | _PID_MAP(HID, 2) | \
                           _PID_MAP(MIDI, 3) | _PID_MAP(VENDOR, 4) | _PID_MAP(NET, 5) )

// String Descriptor Index
enum
{
  STRID_LANGID = 0,
  STRID_MANUFACTURER,
  STRID_PRODUCT,
  STRID_SERIAL,
  STRID_INTERFACE,
  STRID_MAC
};

enum
{
  ITF_NUM_CDC = 0,
  ITF_NUM_CDC_DATA,
  ITF_NUM_TOTAL
};

enum
{
  CONFIG_ID_RNDIS = 0,
  CONFIG_ID_ECM   = 1,
  CONFIG_ID_COUNT
};

//--------------------------------------------------------------------+
// Device Descriptors
//--------------------------------------------------------------------+
tusb_desc_device_t const desc_device =
{
    .bLength            = sizeof(tusb_desc_device_t),
    .bDescriptorType    = TUSB_DESC_DEVICE,
    .bcdUSB             = 0x0200,

    // Use Interface Association Descriptor (IAD) device class
    .bDeviceClass       = TUSB_CLASS_MISC,
    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
    .bDeviceProtocol    = MISC_PROTOCOL_IAD,
    
    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,

    .idVendor           = 0xCafe,
    .idProduct          = USB_PID,
    .bcdDevice          = 0x0101,

    .iManufacturer      = STRID_MANUFACTURER,
    .iProduct           = STRID_PRODUCT,
    .iSerialNumber      = STRID_SERIAL,

    .bNumConfigurations = CONFIG_ID_COUNT // multiple configurations
};

// 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
//--------------------------------------------------------------------+
#define MAIN_CONFIG_TOTAL_LEN    (TUD_CONFIG_DESC_LEN + TUD_RNDIS_DESC_LEN)
#define ALT_CONFIG_TOTAL_LEN     (TUD_CONFIG_DESC_LEN + TUD_CDC_ECM_DESC_LEN)

#if CFG_TUSB_MCU == OPT_MCU_LPC175X_6X || CFG_TUSB_MCU == OPT_MCU_LPC177X_8X || CFG_TUSB_MCU == OPT_MCU_LPC40XX
  // LPC 17xx and 40xx endpoint type (bulk/interrupt/iso) are fixed by its number
  // 0 control, 1 In, 2 Bulk, 3 Iso, 4 In etc ...
  #define EPNUM_NET_NOTIF   0x81
  #define EPNUM_NET_OUT     0x02
  #define EPNUM_NET_IN      0x82

#elif CFG_TUSB_MCU == OPT_MCU_SAMG
  // SAMG doesn't support a same endpoint number with different direction IN and OUT
  //    e.g EP1 OUT & EP1 IN cannot exist together
  #define EPNUM_NET_NOTIF   0x81
  #define EPNUM_NET_OUT     0x02
  #define EPNUM_NET_IN      0x83

#else
  #define EPNUM_NET_NOTIF   0x81
  #define EPNUM_NET_OUT     0x02
  #define EPNUM_NET_IN      0x82
#endif

static uint8_t const rndis_configuration[] =
{
  // Config number (index+1), interface count, string index, total length, attribute, power in mA
  TUD_CONFIG_DESCRIPTOR(CONFIG_ID_RNDIS+1, ITF_NUM_TOTAL, 0, MAIN_CONFIG_TOTAL_LEN, 0, 100),

  // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
  TUD_RNDIS_DESCRIPTOR(ITF_NUM_CDC, STRID_INTERFACE, EPNUM_NET_NOTIF, 8, EPNUM_NET_OUT, EPNUM_NET_IN, CFG_TUD_NET_ENDPOINT_SIZE),
};

static uint8_t const ecm_configuration[] =
{
  // Config number (index+1), interface count, string index, total length, attribute, power in mA
  TUD_CONFIG_DESCRIPTOR(CONFIG_ID_ECM+1, ITF_NUM_TOTAL, 0, ALT_CONFIG_TOTAL_LEN, 0, 100),

  // Interface number, description string index, MAC address string index, EP notification address and size, EP data address (out, in), and size, max segment size.
  TUD_CDC_ECM_DESCRIPTOR(ITF_NUM_CDC, STRID_INTERFACE, STRID_MAC, EPNUM_NET_NOTIF, 64, EPNUM_NET_OUT, EPNUM_NET_IN, CFG_TUD_NET_ENDPOINT_SIZE, CFG_TUD_NET_MTU),
};

// Configuration array: RNDIS and CDC-ECM
// - Windows only works with RNDIS
// - MacOS only works with CDC-ECM
// - Linux will work on both
// Note index is Num-1x
static uint8_t const * const configuration_arr[2] =
{
  [CONFIG_ID_RNDIS] = rndis_configuration,
  [CONFIG_ID_ECM  ] = ecm_configuration
};

// 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)
{
  return (index < CONFIG_ID_COUNT) ? configuration_arr[index] : NULL;
}

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

// array of pointer to string descriptors
static char const* string_desc_arr [] =
{
  [STRID_LANGID]       = (const char[]) { 0x09, 0x04 }, // supported language is English (0x0409)
  [STRID_MANUFACTURER] = "TinyUSB",                     // Manufacturer
  [STRID_PRODUCT]      = "Go to http://192.168.7.1/",   // Product
  //[STRID_SERIAL]       = "123456",                      // Serial
  [STRID_INTERFACE]    = "TinyUSB Network Interface"    // Interface Description

  // STRID_MAC index is handled separately
  // STRID_SERIAL index is handled seperately
};

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;

  unsigned int chr_count = 0;

  if (STRID_LANGID == index)
  {
    memcpy(&_desc_str[1], string_desc_arr[STRID_LANGID], 2);
    chr_count = 1;
  }
  else if (STRID_SERIAL == index)
  {
    pico_unique_board_id_t id;
    pico_get_unique_board_id(&id);
    
    for (unsigned i=0; i<sizeof(id.id); i++)
    {
      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(id.id[i] >> 4) & 0xf];
      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(id.id[i] >> 0) & 0xf];
    }
  }
  else if (STRID_MAC == index)
  {
    // Convert MAC address into UTF-16

    for (unsigned i=0; i<sizeof(tud_network_mac_address); i++)
    {
      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 4) & 0xf];
      _desc_str[1+chr_count++] = "0123456789ABCDEF"[(tud_network_mac_address[i] >> 0) & 0xf];
    }
  }
  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 > (TU_ARRAY_SIZE(_desc_str) - 1)) chr_count = TU_ARRAY_SIZE(_desc_str) - 1;

    // Convert ASCII string into UTF-16
    for (unsigned int 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;
}