Trackball/firmware/src/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 "pico/unique_id.h"
#include "tusb.h"
#include "usb_descriptors.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]         HID | MSC | CDC          [LSB]
 */
#define _PID_MAP(itf, n) ((CFG_TUD_##itf) << (n))
#define USB_PID (0x4200 | _PID_MAP(CDC, 0) | _PID_MAP(MSC, 1) \
    | _PID_MAP(HID, 2) | _PID_MAP(MIDI, 3) | _PID_MAP(VENDOR, 4) )

#define USB_VID   0xCafe
#define USB_BCD   0x0200

//--------------------------------------------------------------------+
// 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;
}

//--------------------------------------------------------------------+
// HID Report Descriptor
//--------------------------------------------------------------------+

uint8_t const desc_hid_report[] = {
    TUD_HID_REPORT_DESC_KEYBOARD( HID_REPORT_ID(REPORT_ID_KEYBOARD         )),
    TUD_HID_REPORT_DESC_MOUSE   ( HID_REPORT_ID(REPORT_ID_MOUSE            )),
    TUD_HID_REPORT_DESC_CONSUMER( HID_REPORT_ID(REPORT_ID_CONSUMER_CONTROL )),
    TUD_HID_REPORT_DESC_GAMEPAD ( HID_REPORT_ID(REPORT_ID_GAMEPAD          ))
};

// Invoked when received GET HID REPORT DESCRIPTOR
// Application return pointer to descriptor
// Descriptor contents must exist long enough for transfer to complete
uint8_t const * tud_hid_descriptor_report_cb(uint8_t instance) {
    (void) instance;
    return desc_hid_report;
}

//--------------------------------------------------------------------+
// Configuration Descriptor
//--------------------------------------------------------------------+

enum {
    ITF_NUM_CDC = 0,
    ITF_NUM_CDC_DATA,
    ITF_NUM_HID,
    ITF_NUM_TOTAL
};

#define  CONFIG_TOTAL_LEN  (TUD_CONFIG_DESC_LEN + TUD_CDC_DESC_LEN + TUD_HID_DESC_LEN)

#define EPNUM_HID       0x81
#define EPNUM_CDC_NOTIF 0x82
#define EPNUM_CDC_OUT   0x02
#define EPNUM_CDC_IN    0x83

uint8_t const desc_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),

    // Interface number, string index, EP notification address and size, EP data address (out, in) and size.
    TUD_CDC_DESCRIPTOR(ITF_NUM_CDC, 4, EPNUM_CDC_NOTIF, 8, EPNUM_CDC_OUT, EPNUM_CDC_IN, 64),

    // Interface number, string index, protocol, report descriptor len, EP In address, size & polling interval
    TUD_HID_DESCRIPTOR(ITF_NUM_HID, 0, HID_ITF_PROTOCOL_NONE, sizeof(desc_hid_report), EPNUM_HID, CFG_TUD_HID_EP_BUFSIZE, 5)
};

#if TUD_OPT_HIGH_SPEED
// Per USB specs: high speed capable device must report device_qualifier and other_speed_configuration

// other speed configuration
uint8_t desc_other_speed_config[CONFIG_TOTAL_LEN];

// device qualifier is mostly similar to device descriptor since we don't change configuration based on speed
tusb_desc_device_qualifier_t const desc_device_qualifier = {
    .bLength            = sizeof(tusb_desc_device_qualifier_t),
    .bDescriptorType    = TUSB_DESC_DEVICE_QUALIFIER,
    .bcdUSB             = USB_BCD,

    .bDeviceClass       = TUSB_CLASS_MISC,
    .bDeviceSubClass    = MISC_SUBCLASS_COMMON,
    .bDeviceProtocol    = MISC_PROTOCOL_IAD,

    .bMaxPacketSize0    = CFG_TUD_ENDPOINT0_SIZE,
    .bNumConfigurations = 0x01,
    .bReserved          = 0x00
};

// Invoked when received GET DEVICE QUALIFIER DESCRIPTOR request
// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete.
// device_qualifier descriptor describes information about a high-speed capable device that would
// change if the device were operating at the other speed. If not highspeed capable stall this request.
uint8_t const* tud_descriptor_device_qualifier_cb(void) {
    return (uint8_t const*) &desc_device_qualifier;
}

// Invoked when received GET OTHER SEED CONFIGURATION DESCRIPTOR request
// Application return pointer to descriptor, whose contents must exist long enough for transfer to complete
// Configuration descriptor in the other speed e.g if high speed then this is for full speed and vice versa
uint8_t const* tud_descriptor_other_speed_configuration_cb(uint8_t index) {
    (void) index; // for multiple configurations

    // other speed config is basically configuration with type = OHER_SPEED_CONFIG
    memcpy(desc_other_speed_config, desc_configuration, CONFIG_TOTAL_LEN);
    desc_other_speed_config[1] = TUSB_DESC_OTHER_SPEED_CONFIG;

    // this example use the same configuration for both high and full speed mode
    return desc_other_speed_config;
}

#endif // highspeed

// 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

    // This example use the same configuration for both high and full speed mode
    return desc_configuration;
}

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

char string_pico_serial[2 * PICO_UNIQUE_BOARD_ID_SIZE_BYTES + 1];

void usb_descriptor_init_id(void) {
    pico_get_unique_board_id_string(string_pico_serial, sizeof(string_pico_serial));
}

// array of pointer to string descriptors
char const* string_desc_arr [] = {
    (const char[]) { 0x09, 0x04 }, // 0: is supported language is English (0x0409)
    "xythobuz",                    // 1: Manufacturer
    "Trackball",                   // 2: Product
    string_pico_serial,            // 3: Serials, should use chip ID
    "Debug Serial",                // 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;
}