Bluetooth: BAP: Shell: Add USB out support for the BAP shell

Add USB out support for the BAP shell, so that decoded LC3
data can be sent to the host (e.g. a PC).

Signed-off-by: Emil Gydesen <[email protected]>

subsys/bluetooth/audio/shell/CMakeLists.txt

@@ -81,6 +81,9 @@ zephyr_library_sources_ifdef(
  CONFIG_BT_BAP_STREAM
  bap.c
  )
+if (CONFIG_BT_AUDIO_RX AND CONFIG_LIBLC3 AND CONFIG_USB_DEVICE_AUDIO)
+ zephyr_library_sources(bap_usb.c)
+endif()
 zephyr_library_sources_ifdef(
  CONFIG_BT_BAP_SCAN_DELEGATOR
  bap_scan_delegator.c

subsys/bluetooth/audio/shell/audio.h

@@ -22,6 +22,8 @@
 
 #include "shell/bt.h"
 
+#define MAX_CODEC_FRAMES_PER_SDU 2
+
 extern struct bt_csip_set_member_svc_inst *svc_inst;
 
 ssize_t audio_ad_data_add(struct bt_data *data, const size_t data_size, const bool discoverable,
@@ -43,6 +45,12 @@ size_t pbp_ad_data_add(struct bt_data data[], size_t data_size);
 
 #if defined(CONFIG_LIBLC3)
 #include "lc3.h"
+
+#define USB_SAMPLE_RATE 48000U
+#define LC3_MAX_SAMPLE_RATE 48000
+#define LC3_MAX_FRAME_DURATION_US 10000
+#define LC3_MAX_NUM_SAMPLES_MONO ((LC3_MAX_FRAME_DURATION_US * LC3_MAX_SAMPLE_RATE) / USEC_PER_SEC)
+#define LC3_MAX_NUM_SAMPLES_STEREO (LC3_MAX_NUM_SAMPLES_MONO * 2)
 #endif /* CONFIG_LIBLC3 */
 
 #define LOCATION BT_AUDIO_LOCATION_FRONT_LEFT | BT_AUDIO_LOCATION_FRONT_RIGHT
@@ -62,6 +70,12 @@ struct named_lc3_preset {
 const struct named_lc3_preset *bap_get_named_preset(bool is_unicast, enum bt_audio_dir dir,
  const char *preset_arg);
 
+int bap_usb_init(void);
+void bap_usb_add_frame(enum bt_audio_location lc3_chan_allocation, const int16_t *frame,
+ size_t frame_size);
+void bap_usb_clear_frames(void);
+void bap_usb_send_frames(void);
+
 #if defined(CONFIG_BT_BAP_UNICAST)
 
 #define UNICAST_SERVER_STREAM_COUNT \
@@ -168,6 +182,22 @@ int cap_ac_unicast(const struct shell *sh, size_t argc, char **argv,
 #endif /* CONFIG_BT_BAP_UNICAST_CLIENT */
 #endif /* CONFIG_BT_BAP_UNICAST */
 
+static inline uint8_t get_chan_cnt(enum bt_audio_location chan_allocation)
+{
+ uint8_t cnt = 0U;
+
+ if (chan_allocation == BT_AUDIO_LOCATION_MONO_AUDIO) {
+ return 1;
+ }
+
+ while (chan_allocation != 0) {
+ cnt += chan_allocation & 1U;
+ chan_allocation >>= 1;
+ }
+
+ return cnt;
+}
+
 static inline void print_qos(const struct shell *sh, const struct bt_audio_codec_qos *qos)
 {
 #if defined(CONFIG_BT_BAP_BROADCAST_SOURCE) || defined(CONFIG_BT_BAP_UNICAST)

subsys/bluetooth/audio/shell/bap.c

@@ -32,10 +32,6 @@
 
 #if defined(CONFIG_LIBLC3)
 
-#define LC3_MAX_SAMPLE_RATE 48000
-#define LC3_MAX_FRAME_DURATION_US 10000
-#define LC3_MAX_NUM_SAMPLES ((LC3_MAX_FRAME_DURATION_US * LC3_MAX_SAMPLE_RATE) / USEC_PER_SEC)
-
 static void clear_lc3_sine_data(struct bt_bap_stream *bap_stream);
 static void lc3_decoder_stream_clear(struct shell_stream *sh_stream);
 
@@ -213,7 +209,7 @@ NET_BUF_POOL_FIXED_DEFINE(sine_tx_pool, CONFIG_BT_ISO_TX_BUF_COUNT, SINE_TX_POOL
 #define AUDIO_VOLUME (INT16_MAX - 3000) /* codec does clipping above INT16_MAX - 3000 */
 #define AUDIO_TONE_FREQUENCY_HZ 400
 
-static int16_t lc3_tx_buf[LC3_MAX_NUM_SAMPLES];
+static int16_t lc3_tx_buf[LC3_MAX_NUM_SAMPLES_MONO];
 static lc3_encoder_t lc3_encoder;
 static lc3_encoder_mem_48k_t lc3_encoder_mem;
 static int lc3_encoder_freq_hz;
@@ -602,7 +598,7 @@ static int lc3_release(struct bt_bap_stream *stream, struct bt_bap_ascs_rsp *rsp
 
 static const struct bt_audio_codec_cap lc3_codec_cap = BT_AUDIO_CODEC_CAP_LC3(
  BT_AUDIO_CODEC_CAP_FREQ_ANY, BT_AUDIO_CODEC_CAP_DURATION_ANY,
- BT_AUDIO_CODEC_CAP_CHAN_COUNT_SUPPORT(1, 2), 30, 240, 2, CONTEXT);
+ BT_AUDIO_CODEC_CAP_CHAN_COUNT_SUPPORT(1, 2), 30, 240, MAX_CODEC_FRAMES_PER_SDU, CONTEXT);
 
 static const struct bt_bap_unicast_server_cb unicast_server_cb = {
  .config = lc3_config,
@@ -2333,7 +2329,7 @@ static struct bt_le_scan_cb bap_scan_cb = {
 static unsigned long recv_stats_interval = 100U;
 
 #if defined(CONFIG_LIBLC3)
-static int16_t lc3_rx_buf[LC3_MAX_NUM_SAMPLES];
+static int16_t lc3_rx_buf[LC3_MAX_NUM_SAMPLES_MONO];
 static lc3_decoder_mem_48k_t lc3_decoder_mem;
 static K_SEM_DEFINE(lc3_decoder_sem, 0, 1); /* used as a signal */
 static int lc3_decoder_frame_duration_us;
@@ -2366,7 +2362,7 @@ static int init_lc3_decoder(const struct shell_stream *sh_stream)
  sh_stream->lc3_frame_duration_us, sh_stream->lc3_freq_hz);
  /* Create the encoder instance. This shall complete before stream_started() is called. */
  lc3_decoder = lc3_setup_decoder(sh_stream->lc3_frame_duration_us, sh_stream->lc3_freq_hz,
- 0, /* No resampling */
+ IS_ENABLED(CONFIG_USB_DEVICE_AUDIO) ? USB_SAMPLE_RATE : 0,
  &lc3_decoder_mem);
  if (lc3_decoder == NULL) {
  shell_error(ctx_shell, "Failed to setup LC3 encoder - wrong parameters?\n");
@@ -2463,12 +2459,44 @@ static void do_lc3_decode(struct shell_stream *sh_stream)
  octets_per_frame * frame_cnt, buf->len);
 
  net_buf_unref(buf);
+ if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+ bap_usb_clear_frames();
+ }
 
  return;
  }
+
+ if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+ const bool has_left = (sh_stream->lc3_chan_allocation &
+ BT_AUDIO_LOCATION_FRONT_LEFT) != 0;
+ const bool has_right = (sh_stream->lc3_chan_allocation &
+ BT_AUDIO_LOCATION_FRONT_RIGHT) != 0;
+ const bool is_mono = sh_stream->lc3_chan_allocation ==
+ BT_AUDIO_LOCATION_MONO_AUDIO;
+ const bool is_left = j == 0 && has_left;
+ const bool is_right = has_right && (j == 0 || (j == 1 && has_left));
+ enum bt_audio_location chan_alloc;
+
+ if (is_left) {
+ chan_alloc = BT_AUDIO_LOCATION_FRONT_LEFT;
+ } else if (is_right) {
+ chan_alloc = BT_AUDIO_LOCATION_FRONT_RIGHT;
+ } else if (is_mono) {
+ chan_alloc = BT_AUDIO_LOCATION_MONO_AUDIO;
+ } else {
+ /* Not suitable for USB */
+ continue;
+ }
+
+ bap_usb_add_frame(chan_alloc, lc3_rx_buf, sizeof(lc3_rx_buf));
+ }
  }
  }
 
+ if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+ bap_usb_send_frames();
+ }
+
  sh_stream->decoded_cnt++;
 
  net_buf_unref(buf);
@@ -2610,24 +2638,6 @@ static void stream_enabled_cb(struct bt_bap_stream *stream)
  }
 }
 
-#if defined(CONFIG_LIBLC3)
-static uint8_t get_chan_cnt(enum bt_audio_location chan_allocation)
-{
- uint8_t cnt = 0U;
-
- if (chan_allocation == BT_AUDIO_LOCATION_MONO_AUDIO) {
- return 1;
- }
-
- while (chan_allocation != 0) {
- cnt += chan_allocation & 1U;
- chan_allocation >>= 1;
- }
-
- return cnt;
-}
-#endif /* CONFIG_LIBLC3 */
-
 static void stream_started_cb(struct bt_bap_stream *bap_stream)
 {
  struct shell_stream *sh_stream = shell_stream_from_bap_stream(bap_stream);
@@ -3368,13 +3378,18 @@ static int cmd_init(const struct shell *sh, size_t argc, char *argv[])
 #if defined(CONFIG_LIBLC3) && defined(CONFIG_BT_AUDIO_RX)
  static K_KERNEL_STACK_DEFINE(lc3_decoder_thread_stack, 4096);
  /* make it slightly lower priority than the RX thread */
- int lc3_decoder_thread_prio = K_PRIO_COOP(CONFIG_BT_RX_PRIO + 1);
+ int lc3_decoder_thread_prio = K_PRIO_PREEMPT(CONFIG_BT_RX_PRIO + 1);
  static struct k_thread lc3_decoder_thread;
 
  k_thread_create(&lc3_decoder_thread, lc3_decoder_thread_stack,
  K_KERNEL_STACK_SIZEOF(lc3_decoder_thread_stack), lc3_decoder_thread_func,
  NULL, NULL, NULL, lc3_decoder_thread_prio, 0, K_NO_WAIT);
  k_thread_name_set(&lc3_decoder_thread, "LC3 Decode");
+
+ if (IS_ENABLED(CONFIG_USB_DEVICE_AUDIO)) {
+ err = bap_usb_init();
+ __ASSERT(err == 0, "Failed to enable USB: %d", err);
+ }
 #endif /* CONFIG_LIBLC3 && CONFIG_BT_AUDIO_RX */
 
  initialized = true;