From 400ff5ab4ce03fc48625d025c8b64b1db243e209 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Sun, 3 Feb 2019 12:08:16 +0100
Subject: [PATCH] hci: calculate SCO payload length based on used hci transport
 and voice settings, drop hacks in sco_demo_util

---
 example/sco_demo_util.c | 14 +-------------
 src/hci.c               | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/example/sco_demo_util.c b/example/sco_demo_util.c
index 4303c1768..cbc358729 100644
--- a/example/sco_demo_util.c
+++ b/example/sco_demo_util.c
@@ -66,7 +66,7 @@
 #define SCO_DEMO_MODE_MICROPHONE 5
 
 // SCO demo configuration
-#define SCO_DEMO_MODE               SCO_DEMO_MODE_ASCII
+#define SCO_DEMO_MODE               SCO_DEMO_MODE_SINE
 
 // number of sco packets until 'report' on console
 #define SCO_REPORT_PERIOD           100
@@ -474,10 +474,6 @@ void sco_demo_send(hci_con_handle_t sco_handle){
 #ifdef ENABLE_HFP_WIDE_BAND_SPEECH
     if (negotiated_codec == HFP_CODEC_MSBC){
 
-        // overwrite
-        sco_payload_length = 24;
-        sco_packet_length = sco_payload_length + 3;
-
         if (hfp_msbc_num_bytes_in_stream() < sco_payload_length){
             log_error("mSBC stream is empty.");
         }
@@ -502,10 +498,6 @@ void sco_demo_send(hci_con_handle_t sco_handle){
     if (negotiated_codec == HFP_CODEC_MSBC){
         // MSBC
 
-        // overwrite
-        sco_payload_length = 24;
-        sco_packet_length = sco_payload_length + 3;
-
         if (audio_input_paused){
             if (btstack_ring_buffer_bytes_available(&audio_input_ring_buffer) >= MSBC_PA_PREBUFFER_BYTES){
                 // resume sending
@@ -580,10 +572,6 @@ void sco_demo_send(hci_con_handle_t sco_handle){
     }
 #else
     // just send '0's
-    if (negotiated_codec == HFP_CODEC_MSBC){
-        sco_payload_length = 24;
-        sco_packet_length = sco_payload_length + 3;
-    }
     memset(sco_packet + 3, 0, sco_payload_length);
 #endif
 #endif
diff --git a/src/hci.c b/src/hci.c
index 1ae2318a7..220b76980 100644
--- a/src/hci.c
+++ b/src/hci.c
@@ -2542,7 +2542,6 @@ static void sco_handler(uint8_t * packet, uint16_t size){
 
     int notify_sco = 0;
 
-#if 0
     // CSR 8811 prefixes 60 byte SCO packet in transparent mode with 20 zero bytes -> skip first 20 payload bytes
     if (hci_stack->manufacturer == BLUETOOTH_COMPANY_ID_CAMBRIDGE_SILICON_RADIO){
         if (size == 83 && ((hci_stack->sco_voice_setting & 0x03) == 0x03)){
@@ -2551,7 +2550,6 @@ static void sco_handler(uint8_t * packet, uint16_t size){
             size = 63;
         }
     }
-#endif
 
     // treat received SCO packets as indicator of successfully sent packet, if flow control is not explicite
     log_info("sco flow %u, handle 0x%04x, packets sent %u, bytes send %u", hci_stack->synchronous_flow_control_enabled, (int) con_handle, conn->num_packets_sent, conn->num_sco_bytes_sent);
@@ -4865,6 +4863,13 @@ uint16_t hci_get_sco_voice_setting(void){
     return hci_stack->sco_voice_setting;
 }
 
+static int hci_have_usb_transport(void){
+    if (!hci_stack->hci_transport) return 0;
+    const char * transport_name = hci_stack->hci_transport->name;
+    if (!transport_name) return 0;
+    return (transport_name[0] == 'H') && (transport_name[1] == '2');
+}
+
 /** @brief Get SCO packet length for current SCO Voice setting
  *  @note  Using SCO packets of the exact length is required for USB transfer
  *  @return Length of SCO packets in bytes (not audio frames)
@@ -4874,13 +4879,18 @@ int hci_get_sco_packet_length(void){
 
 #ifdef ENABLE_CLASSIC
 #ifdef ENABLE_SCO_OVER_HCI
-    // see Core Spec for H2 USB Transfer. 
 
     // CVSD requires twice as much bytes
     int multiplier = hci_stack->sco_voice_setting & 0x0020 ? 2 : 1;
 
-    // 3 byte SCO header + 24 bytes per connection
-    sco_packet_length = 3 + 24 * hci_number_sco_connections() * multiplier;
+    if (hci_have_usb_transport()){
+        // see Core Spec for H2 USB Transfer. 
+        // 3 byte SCO header + 24 bytes per connection
+        sco_packet_length = 3 + 24 * hci_number_sco_connections() * multiplier;
+    } else {
+        // 3 byte SCO header + SCO packet size over the air (60 bytes)
+        sco_packet_length = 3 + 60 * multiplier;
+    }
 #endif
 #endif
     return sco_packet_length;