pw_bluetooth_sapphire: Migrate ReadBufferSize event to emboss

Bug: b/42167863
Test: fx test bt-host-gap-tests
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1096061
GitOrigin-RevId: 11df89844d3506cfd288cf42d3642540a1993cfa
Change-Id: I2394192edf5607f3c2122d1567515f98634fb584
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/230557
Reviewed-by: Lulu Wang <[email protected]>
Lint: Lint 🤖 <[email protected]>
Commit-Queue: Jason Graffius <[email protected]>

pw_bluetooth_sapphire/host/gap/adapter.cc

@@ -1065,27 +1065,26 @@ void AdapterImpl::InitializeStep2() {
         hci::EmbossCommandPacket::New<
             pw::bluetooth::emboss::ReadBufferSizeCommandView>(
             hci_spec::kReadBufferSize),
-        [this](const hci::EventPacket& cmd_complete) {
+        [this](const hci::EmbossEventPacket& cmd_complete) {
           if (hci_is_error(
                   cmd_complete, WARN, "gap", "read buffer size failed")) {
             return;
           }
-          auto params =
-              cmd_complete
-                  .return_params<hci_spec::ReadBufferSizeReturnParams>();
-          uint16_t acl_mtu = pw::bytes::ConvertOrderFrom(
-              cpp20::endian::little, params->hc_acl_data_packet_length);
-          uint16_t acl_max_count = pw::bytes::ConvertOrderFrom(
-              cpp20::endian::little, params->hc_total_num_acl_data_packets);
+          auto packet = cmd_complete.view<
+              pw::bluetooth::emboss::ReadBufferSizeCommandCompleteEventView>();
+          uint16_t acl_mtu = packet.acl_data_packet_length().Read();
+          uint16_t acl_max_count = packet.total_num_acl_data_packets().Read();
           if (acl_mtu && acl_max_count) {
             state_.bredr_data_buffer_info =
                 hci::DataBufferInfo(acl_mtu, acl_max_count);
           }
-          uint16_t sco_mtu = pw::bytes::ConvertOrderFrom(
-              cpp20::endian::little, params->hc_synchronous_data_packet_length);
-          uint16_t sco_max_count = pw::bytes::ConvertOrderFrom(
-              cpp20::endian::little,
-              params->hc_total_num_synchronous_data_packets);
+          // Use UncheckedRead because this field is supposed to
+          // be 0x01-0xFF, but it is possible and harmless for controllers to
+          // set to 0x00 if not supported.
+          uint16_t sco_mtu =
+              packet.synchronous_data_packet_length().UncheckedRead();
+          uint16_t sco_max_count =
+              packet.total_num_synchronous_data_packets().Read();
           if (sco_mtu && sco_max_count) {
             state_.sco_buffer_info =
                 hci::DataBufferInfo(sco_mtu, sco_max_count);

pw_bluetooth_sapphire/host/gap/adapter_test.cc

@@ -1548,7 +1548,7 @@ TEST_F(AdapterTest, ScoDataChannelNotInitializedBecauseBufferInfoNotAvailable) {
   settings.le_acl_data_packet_length = 5;
   settings.le_total_num_acl_data_packets = 1;
   // Ensure SCO buffers are not available.
-  settings.synchronous_data_packet_length = 0;
+  settings.synchronous_data_packet_length = 1;
   settings.total_num_synchronous_data_packets = 0;
   // Enable SCO flow control command.
   constexpr size_t flow_control_enable_octet = 10;

pw_bluetooth_sapphire/host/testing/fake_controller.cc

@@ -77,7 +77,8 @@ void FakeController::Settings::ApplyDualModeDefaults() {
   total_num_acl_data_packets = 1;
   le_acl_data_packet_length = 512;
   le_total_num_acl_data_packets = 1;
-  synchronous_data_packet_length = 0;
+  // Must be 0x01-0xFF, even if not supported
+  synchronous_data_packet_length = 1;
   total_num_synchronous_data_packets = 0;
   iso_data_packet_length = 512;
   total_num_iso_data_packets = 1;
@@ -1934,17 +1935,17 @@ void FakeController::OnCreateConnectionCancel() {
 }
 
 void FakeController::OnReadBufferSize() {
-  hci_spec::ReadBufferSizeReturnParams params;
-  std::memset(&params, 0, sizeof(params));
-  params.hc_acl_data_packet_length = pw::bytes::ConvertOrderTo(
-      cpp20::endian::little, settings_.acl_data_packet_length);
-  params.hc_total_num_acl_data_packets = settings_.total_num_acl_data_packets;
-  params.hc_synchronous_data_packet_length =
-      settings_.synchronous_data_packet_length;
-  params.hc_total_num_synchronous_data_packets =
-      settings_.total_num_synchronous_data_packets;
-  RespondWithCommandComplete(hci_spec::kReadBufferSize,
-                             BufferView(&params, sizeof(params)));
+  auto packet = hci::EmbossEventPacket::New<
+      pwemb::ReadBufferSizeCommandCompleteEventWriter>(
+      hci_spec::kCommandCompleteEventCode);
+  auto view = packet.view_t();
+  view.acl_data_packet_length().Write(settings_.acl_data_packet_length);
+  view.total_num_acl_data_packets().Write(settings_.total_num_acl_data_packets);
+  view.synchronous_data_packet_length().Write(
+      settings_.synchronous_data_packet_length);
+  view.total_num_synchronous_data_packets().Write(
+      settings_.total_num_synchronous_data_packets);
+  RespondWithCommandComplete(hci_spec::kReadBufferSize, &packet);
 }
 
 void FakeController::OnReadBRADDR() {

pw_bluetooth_sapphire/public/pw_bluetooth_sapphire/internal/host/hci-spec/protocol.h

@@ -694,16 +694,6 @@ struct ReadLocalExtendedFeaturesReturnParams {
 // Read Buffer Size Command (v1.1)
 constexpr OpCode kReadBufferSize = InformationalParamsOpCode(0x0005);
 
-struct ReadBufferSizeReturnParams {
-  // See enum StatusCode in hci_constants.h.
-  StatusCode status;
-
-  uint16_t hc_acl_data_packet_length;
-  uint8_t hc_synchronous_data_packet_length;
-  uint16_t hc_total_num_acl_data_packets;
-  uint16_t hc_total_num_synchronous_data_packets;
-} __attribute__((packed));
-
 // ========================================
 // Read BD_ADDR Command (v1.1) (BR/EDR, LE)
 constexpr OpCode kReadBDADDR = InformationalParamsOpCode(0x0009);

pw_bluetooth_sapphire/public/pw_bluetooth_sapphire/internal/host/testing/fake_controller.h

@@ -87,11 +87,11 @@ class FakeController final : public ControllerTestDoubleBase,
     uint8_t supported_commands[64] = {0};
 
     // Buffer Size.
-    uint16_t acl_data_packet_length = 0;
-    uint8_t total_num_acl_data_packets = 0;
+    uint16_t acl_data_packet_length = 1;
+    uint8_t total_num_acl_data_packets = 1;
     uint16_t le_acl_data_packet_length = 0;
     uint8_t le_total_num_acl_data_packets = 0;
-    uint8_t synchronous_data_packet_length = 0;
+    uint8_t synchronous_data_packet_length = 1;
     uint8_t total_num_synchronous_data_packets = 0;
     uint16_t iso_data_packet_length = 0;
     uint8_t total_num_iso_data_packets = 0;