src/main/rx/fport.c

   1 /*
   2  * This file is part of Cleanflight and Betaflight.
   3  *
   4  * Cleanflight and Betaflight are free software. You can redistribute
   5  * this software and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * Cleanflight and Betaflight are distributed in the hope that they
  11  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "platform.h"
  27
  28 #if defined(USE_SERIAL_RX)
  29
  30 #include "build/debug.h"
  31
  32 #include "common/maths.h"
  33 #include "common/utils.h"
  34
  35 #include "drivers/time.h"
  36
  37 #include "io/serial.h"
  38
  39 #ifdef USE_TELEMETRY
  40 #include "telemetry/telemetry.h"
  41 #include "telemetry/smartport.h"
  42 #endif
  43
  44 #include "rx/rx.h"
  45 #include "rx/sbus_channels.h"
  46 #include "rx/fport.h"
  47
  48
  49 #define FPORT_TIME_NEEDED_PER_FRAME_US 3000
  50 #define FPORT_MAX_TELEMETRY_RESPONSE_DELAY_US 2000
  51 #define FPORT_MIN_TELEMETRY_RESPONSE_DELAY_US 500
  52 #define FPORT_MAX_TELEMETRY_AGE_MS 500
  53
  54
  55 #define FPORT_FRAME_MARKER 0x7E
  56
  57 #define FPORT_ESCAPE_CHAR 0x7D
  58 #define FPORT_ESCAPE_MASK 0x20
  59
  60 #define FPORT_CRC_VALUE 0xFF
  61
  62 #define FPORT_BAUDRATE 115200
  63
  64 #define FPORT_PORT_OPTIONS (SERIAL_STOPBITS_1 | SERIAL_PARITY_NO)
  65
  66 enum {
  67     DEBUG_FPORT_FRAME_INTERVAL = 0,
  68     DEBUG_FPORT_FRAME_ERRORS,
  69     DEBUG_FPORT_FRAME_LAST_ERROR,
  70     DEBUG_FPORT_TELEMETRY_DELAY,
  71 };
  72
  73 enum {
  74     DEBUG_FPORT_NO_ERROR = 0,
  75     DEBUG_FPORT_ERROR_TIMEOUT,
  76     DEBUG_FPORT_ERROR_OVERSIZE,
  77     DEBUG_FPORT_ERROR_SIZE,
  78     DEBUG_FPORT_ERROR_CHECKSUM,
  79     DEBUG_FPORT_ERROR_TYPE,
  80     DEBUG_FPORT_ERROR_TYPE_SIZE,
  81 };
  82
  83 enum {
  84     FPORT_FRAME_TYPE_CONTROL = 0x00,
  85     FPORT_FRAME_TYPE_TELEMETRY_REQUEST = 0x01,
  86     FPORT_FRAME_TYPE_TELEMETRY_RESPONSE = 0x81,
  87
  88 };
  89
  90 enum {
  91     FPORT_FRAME_ID_NULL = 0x00,     // (master/slave)
  92     FPORT_FRAME_ID_DATA = 0x10,     // (master/slave)
  93     FPORT_FRAME_ID_READ = 0x30,     // (master)
  94     FPORT_FRAME_ID_WRITE = 0x31,    // (master)
  95     FPORT_FRAME_ID_RESPONSE = 0x32, // (slave)
  96 };
  97
  98 typedef struct fportControlData_s {
  99     sbusChannels_t channels;
 100     uint8_t rssi;
 101 } fportControlData_t;
 102
 103 typedef union fportData_s {
 104     fportControlData_t controlData;
 105     smartPortPayload_t telemetryData;
 106 } fportData_t;
 107
 108 typedef struct fportFrame_s {
 109     uint8_t type;
 110     fportData_t data;
 111 } fportFrame_t;
 112
 113 static const smartPortPayload_t emptySmartPortFrame = { .frameId = 0, .valueId = 0, .data = 0 };
 114
 115 #define FPORT_REQUEST_FRAME_LENGTH sizeof(fportFrame_t)
 116 #define FPORT_RESPONSE_FRAME_LENGTH (sizeof(uint8_t) + sizeof(smartPortPayload_t))
 117
 118 #define FPORT_FRAME_PAYLOAD_LENGTH_CONTROL (sizeof(uint8_t) + sizeof(fportControlData_t))
 119 #define FPORT_FRAME_PAYLOAD_LENGTH_TELEMETRY_REQUEST (sizeof(uint8_t) + sizeof(smartPortPayload_t))
 120
 121 #define NUM_RX_BUFFERS 3
 122 #define BUFFER_SIZE (FPORT_REQUEST_FRAME_LENGTH + 2 * sizeof(uint8_t))
 123
 124 typedef struct fportBuffer_s {
 125     uint8_t data[BUFFER_SIZE];
 126     uint8_t length;
 127 } fportBuffer_t;
 128
 129 static fportBuffer_t rxBuffer[NUM_RX_BUFFERS];
 130
 131 static volatile uint8_t rxBufferWriteIndex = 0;
 132 static volatile uint8_t rxBufferReadIndex = 0;
 133
 134 static volatile timeUs_t lastTelemetryFrameReceivedUs;
 135 static volatile bool clearToSend = false;
 136
 137 static volatile uint8_t framePosition = 0;
 138
 139 static smartPortPayload_t *mspPayload = NULL;
 140 static timeUs_t lastRcFrameReceivedMs = 0;
 141
 142 static serialPort_t *fportPort;
 143 static bool telemetryEnabled = false;
 144
 145 static void reportFrameError(uint8_t errorReason) {
 146     static volatile uint16_t frameErrors = 0;
 147
 148     DEBUG_SET(DEBUG_FPORT, DEBUG_FPORT_FRAME_ERRORS, ++frameErrors);
 149     DEBUG_SET(DEBUG_FPORT, DEBUG_FPORT_FRAME_LAST_ERROR, errorReason);
 150 }
 151
 152 // Receive ISR callback
 153 static void fportDataReceive(uint16_t c, void *data)
 154 {
 155     UNUSED(data);
 156
 157     static timeUs_t frameStartAt = 0;
 158     static bool escapedCharacter = false;
 159     static timeUs_t lastFrameReceivedUs = 0;
 160     static bool telemetryFrame = false;
 161
 162     const timeUs_t currentTimeUs = micros();
 163
 164     clearToSend = false;
 165
 166     if (framePosition > 1 && cmpTimeUs(currentTimeUs, frameStartAt) > FPORT_TIME_NEEDED_PER_FRAME_US + 500) {
 167         reportFrameError(DEBUG_FPORT_ERROR_TIMEOUT);
 168
 169         framePosition = 0;
 170      }
 171
 172     uint8_t val = (uint8_t)c;
 173
 174     if (val == FPORT_FRAME_MARKER) {
 175         if (framePosition > 1) {
 176             const uint8_t nextWriteIndex = (rxBufferWriteIndex + 1) % NUM_RX_BUFFERS;
 177             if (nextWriteIndex != rxBufferReadIndex) {
 178                 rxBuffer[rxBufferWriteIndex].length = framePosition - 1;
 179                 rxBufferWriteIndex = nextWriteIndex;
 180             }
 181
 182             if (telemetryFrame) {
 183                 clearToSend = true;
 184                 lastTelemetryFrameReceivedUs = currentTimeUs;
 185                 telemetryFrame = false;
 186             }
 187
 188             DEBUG_SET(DEBUG_FPORT, DEBUG_FPORT_FRAME_INTERVAL, currentTimeUs - lastFrameReceivedUs);
 189             lastFrameReceivedUs = currentTimeUs;
 190
 191             escapedCharacter = false;
 192         }
 193
 194         frameStartAt = currentTimeUs;
 195         framePosition = 1;
 196     } else if (framePosition > 0) {
 197         if (framePosition >= BUFFER_SIZE + 1) {
 198                 framePosition = 0;
 199
 200                 reportFrameError(DEBUG_FPORT_ERROR_OVERSIZE);
 201         } else {
 202             if (escapedCharacter) {
 203                 val = val ^ FPORT_ESCAPE_MASK;
 204                 escapedCharacter = false;
 205             } else if (val == FPORT_ESCAPE_CHAR) {
 206                 escapedCharacter = true;
 207
 208                 return;
 209             }
 210
 211             if (framePosition == 2 && val == FPORT_FRAME_TYPE_TELEMETRY_REQUEST) {
 212                 telemetryFrame = true;
 213             }
 214
 215             rxBuffer[rxBufferWriteIndex].data[framePosition - 1] = val;
 216             framePosition = framePosition + 1;
 217         }
 218     }
 219 }
 220
 221 #if defined(USE_TELEMETRY_SMARTPORT)
 222 static void smartPortWriteFrameFport(const smartPortPayload_t *payload)
 223 {
 224     framePosition = 0;
 225
 226     uint16_t checksum = 0;
 227     smartPortSendByte(FPORT_RESPONSE_FRAME_LENGTH, &checksum, fportPort);
 228     smartPortSendByte(FPORT_FRAME_TYPE_TELEMETRY_RESPONSE, &checksum, fportPort);
 229     smartPortWriteFrameSerial(payload, fportPort, checksum);
 230 }
 231 #endif
 232
 233 static bool checkChecksum(uint8_t *data, uint8_t length)
 234 {
 235     uint16_t checksum = 0;
 236     for (unsigned i = 0; i < length; i++) {
 237         checksum = checksum + *(uint8_t *)(data + i);
 238     }
 239
 240     checksum = (checksum & 0xff) + (checksum >> 8);
 241
 242     return checksum == FPORT_CRC_VALUE;
 243 }
 244
 245 static uint8_t fportFrameStatus(rxRuntimeConfig_t *rxRuntimeConfig)
 246 {
 247     static smartPortPayload_t payloadBuffer;
 248     static bool hasTelemetryRequest = false;
 249
 250     uint8_t result = RX_FRAME_PENDING;
 251
 252     if (rxBufferReadIndex != rxBufferWriteIndex) {
 253         uint8_t bufferLength = rxBuffer[rxBufferReadIndex].length;
 254         uint8_t frameLength = rxBuffer[rxBufferReadIndex].data[0];
 255         if (frameLength != bufferLength - 2) {
 256             reportFrameError(DEBUG_FPORT_ERROR_SIZE);
 257         } else {
 258             if (!checkChecksum(&rxBuffer[rxBufferReadIndex].data[0], bufferLength)) {
 259                 reportFrameError(DEBUG_FPORT_ERROR_CHECKSUM);
 260             } else {
 261                 fportFrame_t *frame = (fportFrame_t *)&rxBuffer[rxBufferReadIndex].data[1];
 262
 263                 switch (frame->type) {
 264                 case FPORT_FRAME_TYPE_CONTROL:
 265                     if (frameLength != FPORT_FRAME_PAYLOAD_LENGTH_CONTROL) {
 266                         reportFrameError(DEBUG_FPORT_ERROR_TYPE_SIZE);
 267                     } else {
 268                         result = sbusChannelsDecode(rxRuntimeConfig, &frame->data.controlData.channels);
 269
 270                         setRssiUnfiltered(scaleRange(constrain(frame->data.controlData.rssi, 0, 100), 0, 100, 0, 1024), RSSI_SOURCE_RX_PROTOCOL);
 271
 272                         lastRcFrameReceivedMs = millis();
 273                     }
 274
 275                     break;
 276                 case FPORT_FRAME_TYPE_TELEMETRY_REQUEST:
 277                     if (frameLength != FPORT_FRAME_PAYLOAD_LENGTH_TELEMETRY_REQUEST) {
 278                         reportFrameError(DEBUG_FPORT_ERROR_TYPE_SIZE);
 279                     } else {
 280 #if defined(USE_TELEMETRY_SMARTPORT)
 281                         if (!telemetryEnabled) {
 282                             break;
 283                         }
 284
 285                         switch(frame->data.telemetryData.frameId) {
 286                         case FPORT_FRAME_ID_NULL:
 287                         case FPORT_FRAME_ID_DATA: // never used
 288                             hasTelemetryRequest = true;
 289
 290                             break;
 291                         case FPORT_FRAME_ID_READ:
 292                         case FPORT_FRAME_ID_WRITE: // never used
 293                             memcpy(&payloadBuffer, &frame->data.telemetryData, sizeof(smartPortPayload_t));
 294                             mspPayload = &payloadBuffer;
 295
 296                             break;
 297                         default:
 298
 299                            break;
 300                         }
 301 #endif
 302                     }
 303
 304                     break;
 305                 default:
 306                     reportFrameError(DEBUG_FPORT_ERROR_TYPE);
 307
 308                     break;
 309                 }
 310             }
 311
 312         }
 313
 314         rxBufferReadIndex = (rxBufferReadIndex + 1) % NUM_RX_BUFFERS;
 315     }
 316
 317     if ((mspPayload || hasTelemetryRequest) && cmpTimeUs(micros(), lastTelemetryFrameReceivedUs) >= FPORT_MIN_TELEMETRY_RESPONSE_DELAY_US) {
 318         hasTelemetryRequest = false;
 319
 320         result = (result & ~RX_FRAME_PENDING) | RX_FRAME_PROCESSING_REQUIRED;
 321     }
 322
 323     if (lastRcFrameReceivedMs && ((millis() - lastRcFrameReceivedMs) > FPORT_MAX_TELEMETRY_AGE_MS)) {
 324         setRssiFiltered(0, RSSI_SOURCE_RX_PROTOCOL);
 325         lastRcFrameReceivedMs = 0;
 326     }
 327
 328     return result;
 329 }
 330
 331 static bool fportProcessFrame(const rxRuntimeConfig_t *rxRuntimeConfig)
 332 {
 333     UNUSED(rxRuntimeConfig);
 334
 335 #if defined(USE_TELEMETRY_SMARTPORT)
 336     timeUs_t currentTimeUs = micros();
 337     if (cmpTimeUs(currentTimeUs, lastTelemetryFrameReceivedUs) > FPORT_MAX_TELEMETRY_RESPONSE_DELAY_US) {
 338        clearToSend = false;
 339     }
 340
 341     if (clearToSend) {
 342         DEBUG_SET(DEBUG_FPORT, DEBUG_FPORT_TELEMETRY_DELAY, currentTimeUs - lastTelemetryFrameReceivedUs);
 343
 344         processSmartPortTelemetry(mspPayload, &clearToSend, NULL);
 345
 346         if (clearToSend) {
 347             smartPortWriteFrameFport(&emptySmartPortFrame);
 348
 349             clearToSend = false;
 350         }
 351     }
 352
 353     mspPayload = NULL;
 354 #endif
 355
 356     return true;
 357 }
 358
 359 bool fportRxInit(const rxConfig_t *rxConfig, rxRuntimeConfig_t *rxRuntimeConfig)
 360 {
 361     static uint16_t sbusChannelData[SBUS_MAX_CHANNEL];
 362     rxRuntimeConfig->channelData = sbusChannelData;
 363     sbusChannelsInit(rxConfig, rxRuntimeConfig);
 364
 365     rxRuntimeConfig->channelCount = SBUS_MAX_CHANNEL;
 366     rxRuntimeConfig->rxRefreshRate = 11000;
 367
 368     rxRuntimeConfig->rcFrameStatusFn = fportFrameStatus;
 369     rxRuntimeConfig->rcProcessFrameFn = fportProcessFrame;
 370
 371     const serialPortConfig_t *portConfig = findSerialPortConfig(FUNCTION_RX_SERIAL);
 372     if (!portConfig) {
 373         return false;
 374     }
 375
 376     fportPort = openSerialPort(portConfig->identifier,
 377         FUNCTION_RX_SERIAL,
 378         fportDataReceive,
 379         NULL,
 380         FPORT_BAUDRATE,
 381         MODE_RXTX,
 382         FPORT_PORT_OPTIONS | (rxConfig->serialrx_inverted ? SERIAL_INVERTED : 0) | (rxConfig->halfDuplex ? SERIAL_BIDIR : 0)
 383     );
 384
 385     if (fportPort) {
 386 #if defined(USE_TELEMETRY_SMARTPORT)
 387         telemetryEnabled = initSmartPortTelemetryExternal(smartPortWriteFrameFport);
 388 #endif
 389
 390         if (rssiSource == RSSI_SOURCE_NONE) {
 391             rssiSource = RSSI_SOURCE_RX_PROTOCOL;
 392         }
 393     }
 394
 395     return fportPort != NULL;
 396 }
 397 #endif