1 /****************************************************************************** 2 * 3 * Copyright (C) 2014 Google, Inc. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 #define LOG_TAG "bt_hci_h4" 20 21 #include <assert.h> 22 #include <errno.h> 23 #include <string.h> 24 #include <unistd.h> 25 26 #include "hci_hal.h" 27 #include "osi/include/eager_reader.h" 28 #include "osi/include/log.h" 29 #include "osi/include/osi.h" 30 #include "osi/include/reactor.h" 31 #include "osi/include/thread.h" 32 #include "vendor.h" 33 34 #define HCI_HAL_SERIAL_BUFFER_SIZE 1026 35 #define HCI_BLE_EVENT 0x3e 36 37 // Increased HCI thread priority to keep up with the audio sub-system 38 // when streaming time sensitive data (A2DP). 39 #define HCI_THREAD_PRIORITY -19 40 41 #define BT_HCI_UNKNOWN_MESSAGE_TYPE_NUM 1010002 42 43 // Our interface and modules we import 44 static const hci_hal_t interface; 45 static const hci_hal_callbacks_t *callbacks; 46 static const vendor_t *vendor; 47 48 static thread_t *thread; // Not owned by us 49 50 static int uart_fd; 51 static eager_reader_t *uart_stream; 52 static serial_data_type_t current_data_type; 53 static bool stream_has_interpretation; 54 static bool stream_corruption_detected; 55 static uint8_t stream_corruption_bytes_to_ignore; 56 57 static void event_uart_has_bytes(eager_reader_t *reader, void *context); 58 59 // Interface functions 60 61 static bool hal_init(const hci_hal_callbacks_t *upper_callbacks, thread_t *upper_thread) { 62 assert(upper_callbacks != NULL); 63 assert(upper_thread != NULL); 64 65 callbacks = upper_callbacks; 66 thread = upper_thread; 67 return true; 68 } 69 70 static bool hal_open() { 71 LOG_INFO(LOG_TAG, "%s", __func__); 72 // TODO(zachoverflow): close if already open / or don't reopen (maybe at the hci layer level) 73 74 int fd_array[CH_MAX]; 75 int number_of_ports = vendor->send_command(VENDOR_OPEN_USERIAL, &fd_array); 76 77 if (number_of_ports != 1) { 78 LOG_ERROR(LOG_TAG, "%s opened the wrong number of ports: got %d, expected 1.", __func__, number_of_ports); 79 goto error; 80 } 81 82 uart_fd = fd_array[0]; 83 if (uart_fd == INVALID_FD) { 84 LOG_ERROR(LOG_TAG, "%s unable to open the uart serial port.", __func__); 85 goto error; 86 } 87 88 uart_stream = eager_reader_new(uart_fd, &allocator_malloc, HCI_HAL_SERIAL_BUFFER_SIZE, SIZE_MAX, "hci_single_channel"); 89 if (!uart_stream) { 90 LOG_ERROR(LOG_TAG, "%s unable to create eager reader for the uart serial port.", __func__); 91 goto error; 92 } 93 94 stream_has_interpretation = false; 95 stream_corruption_detected = false; 96 stream_corruption_bytes_to_ignore = 0; 97 eager_reader_register(uart_stream, thread_get_reactor(thread), event_uart_has_bytes, NULL); 98 99 // Raise thread priorities to keep up with audio 100 thread_set_priority(thread, HCI_THREAD_PRIORITY); 101 thread_set_priority(eager_reader_get_read_thread(uart_stream), HCI_THREAD_PRIORITY); 102 103 return true; 104 105 error: 106 interface.close(); 107 return false; 108 } 109 110 static void hal_close() { 111 LOG_INFO(LOG_TAG, "%s", __func__); 112 113 eager_reader_free(uart_stream); 114 vendor->send_command(VENDOR_CLOSE_USERIAL, NULL); 115 uart_fd = INVALID_FD; 116 } 117 118 static size_t read_data(serial_data_type_t type, uint8_t *buffer, size_t max_size) { 119 if (type < DATA_TYPE_ACL || type > DATA_TYPE_EVENT) { 120 LOG_ERROR(LOG_TAG, "%s invalid data type: %d", __func__, type); 121 return 0; 122 } else if (!stream_has_interpretation) { 123 LOG_ERROR(LOG_TAG, "%s with no valid stream intepretation.", __func__); 124 return 0; 125 } else if (current_data_type != type) { 126 LOG_ERROR(LOG_TAG, "%s with different type than existing interpretation.", __func__); 127 return 0; 128 } 129 130 return eager_reader_read(uart_stream, buffer, max_size); 131 } 132 133 static void packet_finished(serial_data_type_t type) { 134 if (!stream_has_interpretation) 135 LOG_ERROR(LOG_TAG, "%s with no existing stream interpretation.", __func__); 136 else if (current_data_type != type) 137 LOG_ERROR(LOG_TAG, "%s with different type than existing interpretation.", __func__); 138 139 stream_has_interpretation = false; 140 } 141 142 static uint16_t transmit_data(serial_data_type_t type, uint8_t *data, uint16_t length) { 143 assert(data != NULL); 144 assert(length > 0); 145 146 if (type < DATA_TYPE_COMMAND || type > DATA_TYPE_SCO) { 147 LOG_ERROR(LOG_TAG, "%s invalid data type: %d", __func__, type); 148 return 0; 149 } 150 151 // Write the signal byte right before the data 152 --data; 153 uint8_t previous_byte = *data; 154 *(data) = type; 155 ++length; 156 157 uint16_t transmitted_length = 0; 158 while (length > 0) { 159 ssize_t ret; 160 OSI_NO_INTR(ret = write(uart_fd, data + transmitted_length, length)); 161 switch (ret) { 162 case -1: 163 LOG_ERROR(LOG_TAG, "In %s, error writing to the uart serial port: %s", __func__, strerror(errno)); 164 goto done; 165 case 0: 166 // If we wrote nothing, don't loop more because we 167 // can't go to infinity or beyond 168 goto done; 169 default: 170 transmitted_length += ret; 171 length -= ret; 172 break; 173 } 174 } 175 176 done:; 177 // Be nice and restore the old value of that byte 178 *(data) = previous_byte; 179 180 // Remove the signal byte from our transmitted length, if it was actually written 181 if (transmitted_length > 0) 182 --transmitted_length; 183 184 return transmitted_length; 185 } 186 187 // Internal functions 188 189 // WORKAROUND: 190 // As exhibited by b/23934838, during result-heavy LE scans, the UART byte 191 // stream can get corrupted, leading to assertions caused by mis-interpreting 192 // the bytes following the corruption. 193 // This workaround looks for tell-tale signs of a BLE event and attempts to 194 // skip the correct amount of bytes in the stream to re-synchronize onto 195 // a packet boundary. 196 // Function returns true if |byte_read| has been processed by the workaround. 197 static bool stream_corrupted_during_le_scan_workaround(const uint8_t byte_read) 198 { 199 if (!stream_corruption_detected && byte_read == HCI_BLE_EVENT) { 200 LOG_ERROR(LOG_TAG, "%s HCI stream corrupted (message type 0x3E)!", __func__); 201 stream_corruption_detected = true; 202 return true; 203 } 204 205 if (stream_corruption_detected) { 206 if (stream_corruption_bytes_to_ignore == 0) { 207 stream_corruption_bytes_to_ignore = byte_read; 208 LOG_ERROR(LOG_TAG, "%s About to skip %d bytes...", __func__, stream_corruption_bytes_to_ignore); 209 } else { 210 --stream_corruption_bytes_to_ignore; 211 } 212 213 if (stream_corruption_bytes_to_ignore == 0) { 214 LOG_ERROR(LOG_TAG, "%s Back to our regularly scheduled program...", __func__); 215 stream_corruption_detected = false; 216 } 217 return true; 218 } 219 220 return false; 221 } 222 223 // See what data is waiting, and notify the upper layer 224 static void event_uart_has_bytes(eager_reader_t *reader, UNUSED_ATTR void *context) { 225 if (stream_has_interpretation) { 226 callbacks->data_ready(current_data_type); 227 } else { 228 uint8_t type_byte; 229 if (eager_reader_read(reader, &type_byte, 1) == 0) { 230 LOG_ERROR(LOG_TAG, "%s could not read HCI message type", __func__); 231 return; 232 } 233 234 if (stream_corrupted_during_le_scan_workaround(type_byte)) 235 return; 236 237 if (type_byte < DATA_TYPE_ACL || type_byte > DATA_TYPE_EVENT) { 238 LOG_ERROR(LOG_TAG, "%s Unknown HCI message type 0x%x (min=0x%x max=0x%x). Aborting...", 239 __func__, type_byte, DATA_TYPE_ACL, DATA_TYPE_EVENT); 240 LOG_EVENT_INT(BT_HCI_UNKNOWN_MESSAGE_TYPE_NUM, type_byte); 241 assert(false && "Unknown HCI message type"); 242 return; 243 } 244 245 stream_has_interpretation = true; 246 current_data_type = type_byte; 247 } 248 } 249 250 static const hci_hal_t interface = { 251 hal_init, 252 253 hal_open, 254 hal_close, 255 256 read_data, 257 packet_finished, 258 transmit_data, 259 }; 260 261 const hci_hal_t *hci_hal_h4_get_interface() { 262 vendor = vendor_get_interface(); 263 return &interface; 264 } 265 266 const hci_hal_t *hci_hal_h4_get_test_interface(vendor_t *vendor_interface) { 267 vendor = vendor_interface; 268 return &interface; 269 } 270
