Start with async and HCI
Bug: 205758693
Test: unit tests
Change-Id: I16a8be44bce5f2d233582ab6db17c30d068fa9c0
diff --git a/bluetooth/hci/h4_protocol.cc b/bluetooth/hci/h4_protocol.cc
new file mode 100644
index 0000000..97ba7aa
--- /dev/null
+++ b/bluetooth/hci/h4_protocol.cc
@@ -0,0 +1,144 @@
+/*
+ * Copyright 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "h4_protocol.h"
+
+#define LOG_TAG "android.hardware.bluetooth.hci-h4"
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/uio.h>
+
+#include "log/log.h"
+
+namespace android::hardware::bluetooth::hci {
+
+H4Protocol::H4Protocol(int fd, PacketReadCallback cmd_cb,
+ PacketReadCallback acl_cb, PacketReadCallback sco_cb,
+ PacketReadCallback event_cb, PacketReadCallback iso_cb,
+ DisconnectCallback disconnect_cb)
+ : uart_fd_(fd),
+ cmd_cb_(std::move(cmd_cb)),
+ acl_cb_(std::move(acl_cb)),
+ sco_cb_(std::move(sco_cb)),
+ event_cb_(std::move(event_cb)),
+ iso_cb_(std::move(iso_cb)),
+ disconnect_cb_(std::move(disconnect_cb)) {}
+
+size_t H4Protocol::Send(PacketType type, const std::vector<uint8_t>& vector) {
+ return Send(type, vector.data(), vector.size());
+}
+
+size_t H4Protocol::Send(PacketType type, const uint8_t* data, size_t length) {
+ /* For HCI communication over USB dongle, multiple write results in
+ * response timeout as driver expect type + data at once to process
+ * the command, so using "writev"(for atomicity) here.
+ */
+ struct iovec iov[2];
+ ssize_t ret = 0;
+ iov[0].iov_base = &type;
+ iov[0].iov_len = sizeof(type);
+ iov[1].iov_base = (void*)data;
+ iov[1].iov_len = length;
+ while (1) {
+ ret = TEMP_FAILURE_RETRY(writev(uart_fd_, iov, 2));
+ if (ret == -1) {
+ if (errno == EAGAIN) {
+ ALOGE("%s error writing to UART (%s)", __func__, strerror(errno));
+ continue;
+ }
+ } else if (ret == 0) {
+ // Nothing written :(
+ ALOGE("%s zero bytes written - something went wrong...", __func__);
+ break;
+ }
+ break;
+ }
+ return ret;
+}
+
+size_t H4Protocol::OnPacketReady(const std::vector<uint8_t>& packet) {
+ switch (hci_packet_type_) {
+ case PacketType::COMMAND:
+ cmd_cb_(packet);
+ break;
+ case PacketType::ACL_DATA:
+ acl_cb_(packet);
+ break;
+ case PacketType::SCO_DATA:
+ sco_cb_(packet);
+ break;
+ case PacketType::EVENT:
+ event_cb_(packet);
+ break;
+ case PacketType::ISO_DATA:
+ iso_cb_(packet);
+ break;
+ default: {
+ LOG_ALWAYS_FATAL("Bad packet type 0x%x",
+ static_cast<int>(hci_packet_type_));
+ }
+ }
+ return packet.size();
+}
+
+void H4Protocol::SendDataToPacketizer(uint8_t* buffer, size_t length) {
+ std::vector<uint8_t> input_buffer{buffer, buffer + length};
+ size_t buffer_offset = 0;
+ while (buffer_offset < input_buffer.size()) {
+ if (hci_packet_type_ == PacketType::UNKNOWN) {
+ hci_packet_type_ =
+ static_cast<PacketType>(input_buffer.data()[buffer_offset]);
+ buffer_offset += 1;
+ } else {
+ bool packet_ready = hci_packetizer_.OnDataReady(
+ hci_packet_type_, input_buffer, buffer_offset);
+ if (packet_ready) {
+ // Call packet callback and move offset.
+ buffer_offset += OnPacketReady(hci_packetizer_.GetPacket());
+ // Get ready for the next type byte.
+ hci_packet_type_ = PacketType::UNKNOWN;
+ } else {
+ // The data was consumed, but there wasn't a packet.
+ buffer_offset = input_buffer.size();
+ }
+ }
+ }
+}
+
+void H4Protocol::OnDataReady() {
+ if (disconnected_) {
+ return;
+ }
+ uint8_t buffer[kMaxPacketLength];
+ ssize_t bytes_read =
+ TEMP_FAILURE_RETRY(read(uart_fd_, buffer, kMaxPacketLength));
+ if (bytes_read == 0) {
+ ALOGI("No bytes read, calling the disconnect callback");
+ disconnected_ = true;
+ disconnect_cb_();
+ return;
+ }
+ if (bytes_read < 0) {
+ ALOGW("error reading from UART (%s)", strerror(errno));
+ return;
+ }
+ SendDataToPacketizer(buffer, bytes_read);
+}
+
+} // namespace android::hardware::bluetooth::hci