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//
// Copyright 2017 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 <android-base/logging.h>
#include <assert.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <utils/Log.h>
namespace android {
namespace hardware {
namespace bluetooth {
namespace hci {
size_t H4Protocol::Send(uint8_t 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;
}
void H4Protocol::OnPacketReady() {
switch (hci_packet_type_) {
case HCI_PACKET_TYPE_EVENT:
event_cb_(hci_packetizer_.GetPacket());
break;
case HCI_PACKET_TYPE_ACL_DATA:
acl_cb_(hci_packetizer_.GetPacket());
break;
case HCI_PACKET_TYPE_SCO_DATA:
sco_cb_(hci_packetizer_.GetPacket());
break;
case HCI_PACKET_TYPE_ISO_DATA:
iso_cb_(hci_packetizer_.GetPacket());
break;
default: {
bool bad_packet_type = true;
CHECK(!bad_packet_type);
}
}
// Get ready for the next type byte.
hci_packet_type_ = HCI_PACKET_TYPE_UNKNOWN;
}
void H4Protocol::OnDataReady(int fd) {
if (hci_packet_type_ == HCI_PACKET_TYPE_UNKNOWN) {
/**
* read full buffer. ACL max length is 2 bytes, and SCO max length is 2
* byte. so taking 64K as buffer length.
* Question : Why to read in single chunk rather than multiple reads,
* which can give parameter length arriving in response ?
* Answer: The multiple reads does not work with BT USB dongle. At least
* with Bluetooth 2.0 supported USB dongle. After first read, either
* firmware/kernel (do not know who is responsible - inputs ??) driver
* discard the whole message and successive read results in forever
* blocking loop. - Is there any other way to make it work with multiple
* reads, do not know yet (it can eliminate need of this function) ?
* Reading in single shot gives expected response.
*/
const size_t max_plen = 64*1024;
hidl_vec<uint8_t> tpkt;
tpkt.resize(max_plen);
ssize_t bytes_read = TEMP_FAILURE_RETRY(read(fd, tpkt.data(), max_plen));
if (bytes_read == 0) {
ALOGI("No bytes read");
return;
}
if (bytes_read < 0) {
ALOGW("error reading from UART (%s)", strerror(errno));
return;
}
hci_packet_type_ = static_cast<HciPacketType>(tpkt.data()[0]);
hci_packetizer_.CbHciPacket(tpkt.data()+1, bytes_read-1);
}
}
} // namespace hci
} // namespace bluetooth
} // namespace hardware
} // namespace android
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