firmware/src/MeshRadio.cpp

#include <SPI.h>
#include "RH_RF95.h"
#include <RHMesh.h>
#include <assert.h>

#include <pb_encode.h>
#include <pb_decode.h>
#include "MeshRadio.h"
#include "configuration.h"
#include "NodeDB.h"

// Change to 434.0 or other frequency, must match RX's freq!  FIXME, choose a better default value
#define RF95_FREQ_US 902.0f

MeshRadio::MeshRadio(MemoryPool<MeshPacket> &_pool, PointerQueue<MeshPacket> &_rxDest)
    : rf95(NSS_GPIO, DIO0_GPIO),
      manager(rf95),
      pool(_pool),
      rxDest(_rxDest),
      txQueue(MAX_TX_QUEUE)
{
  //radioConfig.modem_config = RadioConfig_ModemConfig_Bw125Cr45Sf128;  // medium range and fast
  radioConfig.modem_config = RadioConfig_ModemConfig_Bw500Cr45Sf128;  // short range and fast, but wide bandwidth so incompatible radios can talk together
  //radioConfig.modem_config = RadioConfig_ModemConfig_Bw125Cr48Sf4096; // slow and long range

  radioConfig.tx_power = 23;
  radioConfig.center_freq = RF95_FREQ_US; // FIXME, pull this config from flash
}

bool MeshRadio::init()
{
#ifdef RESET_GPIO
  pinMode(RESET_GPIO, OUTPUT); // Deassert reset
  digitalWrite(RESET_GPIO, HIGH);

  // pulse reset
  digitalWrite(RESET_GPIO, LOW);
  delay(10);
  digitalWrite(RESET_GPIO, HIGH);
  delay(10);
#endif

  manager.setThisAddress(nodeDB.getNodeNum()); // Note: we must do this here, because the nodenum isn't inited at constructor time.

  if (!manager.init())
  {
    DEBUG_MSG("LoRa radio init failed\n");
    DEBUG_MSG("Uncomment '#define SERIAL_DEBUG' in RH_RF95.cpp for detailed debug info\n");
    return false;
  }

  // not needed - defaults on
  // rf95.setPayloadCRC(true);

  reloadConfig();

  return true;
}

void MeshRadio::reloadConfig()
{
  rf95.setModeIdle();

  // Set up default configuration
  // No Sync Words in LORA mode.
  rf95.setModemConfig((RH_RF95::ModemConfigChoice)radioConfig.modem_config); // Radio default
                                                                             //    setModemConfig(Bw125Cr48Sf4096); // slow and reliable?
  // rf95.setPreambleLength(8);           // Default is 8

  // Defaults after init are 434.0MHz, modulation GFSK_Rb250Fd250, +13dbM
  if (!rf95.setFrequency(radioConfig.center_freq))
  {
    DEBUG_MSG("setFrequency failed\n");
    assert(0); // fixme panic
  }

  // Defaults after init are 434.0MHz, 13dBm, Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on

  // The default transmitter power is 13dBm, using PA_BOOST.
  // If you are using RFM95/96/97/98 modules which uses the PA_BOOST transmitter pin, then
  // you can set transmitter powers from 5 to 23 dBm:
  // FIXME - can we do this?  It seems to be in the Heltec board.
  rf95.setTxPower(radioConfig.tx_power, false);

  DEBUG_MSG("Set radio: config=%u, freq=%f, txpower=%d\n", radioConfig.modem_config, radioConfig.center_freq, radioConfig.tx_power);
}

ErrorCode MeshRadio::send(MeshPacket *p)
{
  DEBUG_MSG("enquing packet for send from=0x%x, to=0x%x\n", p->from, p->to);
  return txQueue.enqueue(p, 0); // nowait
}

ErrorCode MeshRadio::sendTo(NodeNum dest, const uint8_t *buf, size_t len)
{
  // We must do this before each send, because we might have just changed our nodenum
  manager.setThisAddress(nodeDB.getNodeNum()); // Note: we must do this here, because the nodenum isn't inited at constructor time.

  assert(len <= 251); // Make sure we don't overflow the tiny max packet size

  uint32_t start = millis();
  // Note: we don't use sendToWait here because we don't want to wait and for the time being don't require
  // reliable delivery
  // return manager.sendtoWait((uint8_t *) buf, len, dest);
  ErrorCode res = manager.sendto((uint8_t *)buf, len, dest) ? ERRNO_OK : ERRNO_UNKNOWN;

  // FIXME, we have to wait for sending to complete before freeing the buffer, otherwise it might get wiped
  // instead just have the radiohead layer understand queues.
  if (res == ERRNO_OK)
    manager.waitPacketSent();

  DEBUG_MSG("mesh sendTo %d bytes to 0x%x (%lu msecs)\n", len, dest, millis() - start);

  return res;
}

/// enqueue a received packet in rxDest
void MeshRadio::handleReceive(MeshPacket *mp)
{
  int res = rxDest.enqueue(mp, 0); // NOWAIT - fixme, if queue is full, delete older messages
  assert(res == pdTRUE);
}

void MeshRadio::loop()
{
  // FIXME read from radio with recvfromAckTimeout

#if 0
static int16_t packetnum = 0;  // packet counter, we increment per xmission

  char radiopacket[20] = "Hello World #      ";
  sprintf(radiopacket, "hello %d", packetnum++);
  
  assert(sendTo(NODENUM_BROADCAST, (uint8_t *)radiopacket, sizeof(radiopacket)) == ERRNO_OK);
#endif

  /// A temporary buffer used for sending/receving packets, sized to hold the biggest buffer we might need
  static uint8_t radiobuf[SubPacket_size];
  uint8_t rxlen;
  uint8_t srcaddr, destaddr, id, flags;

  assert(SubPacket_size < 251); // a hard limit from the radio stack (including 4 bytes of headers)

  // Poll to see if we've received a packet
  //   if (manager.recvfromAckTimeout(radiobuf, &rxlen, 0, &srcaddr, &destaddr, &id, &flags))
  // prefill rxlen with the max length we can accept - very important
  rxlen = sizeof(radiobuf);
  if (manager.recvfrom(radiobuf, &rxlen, &srcaddr, &destaddr, &id, &flags))
  {
    // We received a packet
    int32_t freqerr = rf95.frequencyError(), snr = rf95.lastSNR();
    DEBUG_MSG("Received packet from mesh src=0x%x,dest=0x%x,id=%d,len=%d rxGood=%d,rxBad=%d,freqErr=%d,snr=%d\n",
              srcaddr, destaddr, id, rxlen, rf95.rxGood(), rf95.rxBad(), freqerr, snr);

    MeshPacket *mp = pool.allocZeroed();

    SubPacket *p = &mp->payload;

    mp->from = srcaddr;
    mp->to = destaddr;

    // If we already have an entry in the DB for this nodenum, goahead and hide the snr/freqerr info there.
    // Note: we can't create it at this point, because it might be a bogus User node allocation.  But odds are we will
    // already have a record we can hide this debugging info in.
    NodeInfo *info = nodeDB.getNode(mp->from);
    if (info)
    {
      info->snr = snr;
      info->frequency_error = freqerr;
    }

    if (!pb_decode_from_bytes(radiobuf, rxlen, SubPacket_fields, p))
    {
      pool.release(mp);
    }
    else
    {
      // parsing was successful, queue for our recipient
      mp->has_payload = true;
      handleReceive(mp);
    }
  }

  // Poll to see if we need to send any packets
  MeshPacket *txp = txQueue.dequeuePtr(0); // nowait
  if (txp)
  {
    DEBUG_MSG("sending queued packet on mesh (txGood=%d,rxGood=%d,rxBad=%d)\n", rf95.txGood(), rf95.rxGood(), rf95.rxBad());
    assert(txp->has_payload);

    size_t numbytes = pb_encode_to_bytes(radiobuf, sizeof(radiobuf), SubPacket_fields, &txp->payload);

    int res = sendTo(txp->to, radiobuf, numbytes);
    assert(res == ERRNO_OK);

    bool loopbackTest = false; // if true we will pretend to receive any packets we just sent
    if (loopbackTest)
      handleReceive(txp);
    else
      pool.release(txp);

    DEBUG_MSG("Done with send\n");
  }
}