dev_audio_headset.c

/* 
 * The MIT License (MIT)
 *
 * Copyright (c) 2020 Jerzy Kasenberg
 *
 * 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 <stdio.h>
#include <string.h>

#include "bsp/board.h"
#include "tusb.h"
#include "usb_descriptors.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF PROTOTYPES
//--------------------------------------------------------------------+

/* Blink pattern
 * - 25 ms   : streaming data
 * - 250 ms  : device not mounted
 * - 1000 ms : device mounted
 * - 2500 ms : device is suspended
 */
enum {
    BLINK_STREAMING = 25,
    BLINK_NOT_MOUNTED = 250,
    BLINK_MOUNTED = 1000,
    BLINK_SUSPENDED = 2500,
};

enum {
    VOLUME_CTRL_0_DB = 0,
    VOLUME_CTRL_10_DB = 2560,
    VOLUME_CTRL_20_DB = 5120,
    VOLUME_CTRL_30_DB = 7680,
    VOLUME_CTRL_40_DB = 10240,
    VOLUME_CTRL_50_DB = 12800,
    VOLUME_CTRL_60_DB = 15360,
    VOLUME_CTRL_70_DB = 17920,
    VOLUME_CTRL_80_DB = 20480,
    VOLUME_CTRL_90_DB = 23040,
    VOLUME_CTRL_100_DB = 25600,
    VOLUME_CTRL_SILENCE = 0x8000,
};

static uint32_t blink_interval_ms = BLINK_NOT_MOUNTED;

// Audio controls
// Current states
int8_t mute[CFG_TUD_AUDIO_N_CHANNELS_TX + 1];       // +1 for master channel 0
int16_t volume[CFG_TUD_AUDIO_N_CHANNELS_TX + 1];    // +1 for master channel 0

// Buffer for microphone data
int16_t mic_buf[1000];
// Buffer for speaker data
int16_t spk_buf[1000];
// Speaker data size received in the last frame
int spk_data_size;

void led_blinking_task(void);
void audio_task(void);

/*------------- MAIN -------------*/
int main(void) {
    board_init();

    tusb_init();

    TU_LOG1("Headset running\r\n");

    while (1) {
        tud_task(); // TinyUSB device task
        audio_task();
        led_blinking_task();
    }

    return 0;
}

//--------------------------------------------------------------------+
// Device callbacks
//--------------------------------------------------------------------+

// Invoked when device is mounted
void tud_mount_cb(void) {
    blink_interval_ms = BLINK_MOUNTED;
}

// Invoked when device is unmounted
void tud_umount_cb(void) {
    blink_interval_ms = BLINK_NOT_MOUNTED;
}

// Invoked when usb bus is suspended
// remote_wakeup_en : if host allow us  to perform remote wakeup
// Within 7ms, device must draw an average of current less than 2.5 mA from bus
void tud_suspend_cb(bool remote_wakeup_en) {
    (void) remote_wakeup_en;
    blink_interval_ms = BLINK_SUSPENDED;
}

// Invoked when usb bus is resumed
void tud_resume_cb(void) {
    blink_interval_ms = BLINK_MOUNTED;
}

typedef struct TU_ATTR_PACKED {
    union {
        struct TU_ATTR_PACKED {
            uint8_t recipient: 5; ///< Recipient type tusb_request_recipient_t.
            uint8_t type: 2; ///< Request type tusb_request_type_t.
            uint8_t direction: 1; ///< Direction type. tusb_dir_t
        } bmRequestType_bit;

        uint8_t bmRequestType;
    };

    audio_cs_req_t bRequest;
    uint8_t bChannelNumber;
    uint8_t bControlSelector;
    union {
        uint8_t bInterface;
        uint8_t bEndpoint;
    };
    uint8_t bEntityID;
    uint16_t wLength;
} audio_control_request_t;

// Helper for clock get requests
static bool tud_audio_clock_get_request(uint8_t rhport, audio_control_request_t const *request) {
    TU_ASSERT(request->bEntityID == UAC2_ENTITY_CLOCK);

    // Example supports only single frequency, same value will be used for current value and range
    if (request->bControlSelector == AUDIO_CS_CTRL_SAM_FREQ) {
        if (request->bRequest == AUDIO_CS_REQ_CUR) {
            TU_LOG2("Clock get current freq %u\r\n", AUDIO_SAMPLE_RATE);

            audio_control_cur_4_t curf = {tu_htole32(AUDIO_SAMPLE_RATE)};
            return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request, &curf,
                                                              sizeof(curf));
        } else if (request->bRequest == AUDIO_CS_REQ_RANGE) {
            audio_control_range_4_n_t(1) rangef =
                    {
                            .wNumSubRanges = tu_htole16(1),
                            .subrange[0] = {tu_htole32(AUDIO_SAMPLE_RATE), tu_htole32(AUDIO_SAMPLE_RATE), 0}
                    };
            TU_LOG2("Clock get freq range (%d, %d, %d)\r\n", (int) rangef.subrange[0].bMin,
                    (int) rangef.subrange[0].bMax, (int) rangef.subrange[0].bRes);
            return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request, &rangef,
                                                              sizeof(rangef));
        }
    } else if (request->bControlSelector == AUDIO_CS_CTRL_CLK_VALID &&
               request->bRequest == AUDIO_CS_REQ_CUR) {
        audio_control_cur_1_t cur_valid = {.bCur = 1};
        TU_LOG2("Clock get is valid %u\r\n", cur_valid.bCur);
        return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request, &cur_valid,
                                                          sizeof(cur_valid));
    }
    TU_LOG1("Clock get request not supported, entity = %u, selector = %u, request = %u\r\n",
            request->bEntityID, request->bControlSelector, request->bRequest);
    return false;
}

// Helper for feature unit get requests
static bool tud_audio_feature_unit_get_request(uint8_t rhport, audio_control_request_t const *request) {
    TU_ASSERT(request->bEntityID == UAC2_ENTITY_SPK_FEATURE_UNIT);

    if (request->bControlSelector == AUDIO_FU_CTRL_MUTE && request->bRequest == AUDIO_CS_REQ_CUR) {
        audio_control_cur_1_t mute1 = {.bCur = mute[request->bChannelNumber]};
        TU_LOG2("Get channel %u mute %d\r\n", request->bChannelNumber, mute1.bCur);
        return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request, &mute1,
                                                          sizeof(mute1));
    } else if (UAC2_ENTITY_SPK_FEATURE_UNIT && request->bControlSelector == AUDIO_FU_CTRL_VOLUME) {
        if (request->bRequest == AUDIO_CS_REQ_RANGE) {
            audio_control_range_2_n_t(1) range_vol = {
                    .wNumSubRanges = tu_htole16(1),
                    .subrange[0] = {.bMin = tu_htole16(-VOLUME_CTRL_50_DB), tu_htole16(VOLUME_CTRL_0_DB),
                                                                            tu_htole16(256)}
            };
            TU_LOG2("Get channel %u volume range (%d, %d, %u) dB\r\n", request->bChannelNumber,
                    range_vol.subrange[0].bMin / 256, range_vol.subrange[0].bMax / 256,
                    range_vol.subrange[0].bRes / 256);
            return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request,
                                                              &range_vol, sizeof(range_vol));
        } else if (request->bRequest == AUDIO_CS_REQ_CUR) {
            audio_control_cur_2_t cur_vol = {.bCur = tu_htole16(volume[request->bChannelNumber])};
            TU_LOG2("Get channel %u volume %u dB\r\n", request->bChannelNumber, cur_vol.bCur);
            return tud_audio_buffer_and_schedule_control_xfer(rhport, (tusb_control_request_t const *) request,
                                                              &cur_vol, sizeof(cur_vol));
        }
    }
    TU_LOG1("Feature unit get request not supported, entity = %u, selector = %u, request = %u\r\n",
            request->bEntityID, request->bControlSelector, request->bRequest);

    return false;
}

// Helper for feature unit set requests
static bool tud_audio_feature_unit_set_request(uint8_t rhport, audio_control_request_t const *request,
                                               uint8_t const *buf) {
    (void) rhport;

    TU_ASSERT(request->bEntityID == UAC2_ENTITY_SPK_FEATURE_UNIT);
    TU_VERIFY(request->bRequest == AUDIO_CS_REQ_CUR);

    if (request->bControlSelector == AUDIO_FU_CTRL_MUTE) {
        TU_VERIFY(request->wLength == sizeof(audio_control_cur_1_t));

        mute[request->bChannelNumber] = ((audio_control_cur_1_t *) buf)->bCur;

        TU_LOG2("Set channel %d Mute: %d\r\n", request->bChannelNumber, mute[request->bChannelNumber]);

        return true;
    } else if (request->bControlSelector == AUDIO_FU_CTRL_VOLUME) {
        TU_VERIFY(request->wLength == sizeof(audio_control_cur_2_t));

        volume[request->bChannelNumber] = ((audio_control_cur_2_t const *) buf)->bCur;

        TU_LOG2("Set channel %d volume: %d dB\r\n", request->bChannelNumber, volume[request->bChannelNumber] / 256);

        return true;
    } else {
        TU_LOG1("Feature unit set request not supported, entity = %u, selector = %u, request = %u\r\n",
                request->bEntityID, request->bControlSelector, request->bRequest);
        return false;
    }
}

//--------------------------------------------------------------------+
// Application Callback API Implementations
//--------------------------------------------------------------------+

// Invoked when audio class specific get request received for an entity
bool tud_audio_get_req_entity_cb(uint8_t rhport, tusb_control_request_t const *p_request) {
    audio_control_request_t *request = (audio_control_request_t *) p_request;

    if (request->bEntityID == UAC2_ENTITY_CLOCK)
        return tud_audio_clock_get_request(rhport, request);
    if (request->bEntityID == UAC2_ENTITY_SPK_FEATURE_UNIT)
        return tud_audio_feature_unit_get_request(rhport, request);
    else {
        TU_LOG1("Get request not handled, entity = %d, selector = %d, request = %d\r\n",
                request->bEntityID, request->bControlSelector, request->bRequest);
    }
    return false;
}

// Invoked when audio class specific set request received for an entity
bool tud_audio_set_req_entity_cb(uint8_t rhport, tusb_control_request_t const *p_request, uint8_t *buf) {
    audio_control_request_t const *request = (audio_control_request_t const *) p_request;

    if (request->bEntityID == UAC2_ENTITY_SPK_FEATURE_UNIT)
        return tud_audio_feature_unit_set_request(rhport, request, buf);

    TU_LOG1("Set request not handled, entity = %d, selector = %d, request = %d\r\n",
            request->bEntityID, request->bControlSelector, request->bRequest);

    return false;
}

bool tud_audio_set_itf_close_EP_cb(uint8_t rhport, tusb_control_request_t const *p_request) {
    (void) rhport;

    uint8_t const itf = tu_u16_low(tu_le16toh(p_request->wIndex));
    uint8_t const alt = tu_u16_low(tu_le16toh(p_request->wValue));

    if (ITF_NUM_AUDIO_STREAMING_SPK == itf && alt == 0)
        blink_interval_ms = BLINK_MOUNTED;

    return true;
}

bool tud_audio_set_itf_cb(uint8_t rhport, tusb_control_request_t const *p_request) {
    (void) rhport;
    uint8_t const itf = tu_u16_low(tu_le16toh(p_request->wIndex));
    uint8_t const alt = tu_u16_low(tu_le16toh(p_request->wValue));

    TU_LOG2("Set interface %d alt %d\r\n", itf, alt);
    if (ITF_NUM_AUDIO_STREAMING_SPK == itf && alt != 0)
        blink_interval_ms = BLINK_STREAMING;

    return true;
}

bool tud_audio_rx_done_cb(uint8_t rhport, uint8_t *buffer, uint16_t buf_size) {
    (void) rhport;

    spk_data_size = buf_size;
    memcpy(spk_buf, buffer, buf_size);

    return true;
}

bool tud_audio_tx_done_pre_load_cb(uint8_t rhport, uint8_t itf, uint8_t ep_in, uint8_t cur_alt_setting) {
    (void) rhport;
    (void) itf;
    (void) ep_in;
    (void) cur_alt_setting;

    // This callback could be used to fill microphone data separately
    return true;
}

//--------------------------------------------------------------------+
// AUDIO Task
//--------------------------------------------------------------------+

void audio_task(void) {
    // When new data arrived, copy data from speaker buffer, to microphone buffer
    // and send it over
    if (spk_data_size) {
        int16_t *src = spk_buf;
        int16_t *limit = spk_buf + spk_data_size / 2;
        int16_t *dst = mic_buf;
        while (src < limit) {
            // Combine two channels into one
            int32_t left = *src++;
            int32_t right = *src++;
            *dst++ = (int16_t) ((left + right) / 2);
        }
        tud_audio_write((uint8_t *) mic_buf, spk_data_size / 2);
        spk_data_size = 0;
    }
}

//--------------------------------------------------------------------+
// BLINKING TASK
//--------------------------------------------------------------------+
void led_blinking_task(void) {
    static uint32_t start_ms = 0;
    static bool led_state = false;

    // Blink every interval ms
    if (board_millis() - start_ms < blink_interval_ms) return;
    start_ms += blink_interval_ms;

    board_led_write(led_state);
    led_state = 1 - led_state;
}