Bridge library to the 1.5 format

libraries/Bridge/src/Bridge.cpp

@@ -0,0 +1,229 @@
+/*
+  Copyright (c) 2013 Arduino LLC. All right reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#include "Bridge.h"
+#include <util/crc16.h>
+
+BridgeClass::BridgeClass(Stream &_stream) :
+  index(0), stream(_stream), started(false), max_retries(0) {
+  // Empty
+}
+
+void BridgeClass::begin() {
+  if (started)
+    return;
+  started = true;
+  
+  // Wait for U-boot to finish startup
+  do {
+    dropAll();
+    delay(1000);
+  } while (stream.available()>0);
+
+  while (true) {
+    // Bridge interrupt:
+    // - Ask the bridge to close itself
+    uint8_t quit_cmd[] = {'X','X','X','X','X'};
+    max_retries = 1;
+    transfer(quit_cmd, 5);
+
+    // Bridge startup:
+    // - If the bridge is not running starts it safely
+    stream.print(CTRL_C);
+    delay(250);
+    stream.print(F("\n"));
+    delay(250);
+    stream.print(F("\n"));
+    delay(500);
+    // Wait for OpenWRT message
+    // "Press enter to activate console"
+    stream.print(F("run-bridge\n"));
+    delay(500);
+    dropAll();
+  
+    // Reset the brigde to check if it is running
+    uint8_t cmd[] = {'X','X', '1','0','0'};
+    uint8_t res[1];
+    max_retries = 50;
+    uint16_t l = transfer(cmd, 5, res, 1);
+    if (l == TRANSFER_TIMEOUT) {
+      // Bridge didn't start...
+      // Maybe the board is starting-up?
+
+      // Wait and retry
+      delay(1000);
+      continue;
+    }
+    if (res[0] != 0)
+	  while (true);
+
+    max_retries = 50;
+    return;
+  }
+}
+
+void BridgeClass::put(const char *key, const char *value) {
+  // TODO: do it in a more efficient way
+  String cmd = "D";
+  cmd += key;
+  cmd += "\xFE";
+  cmd += value;
+  transfer((uint8_t*)cmd.c_str(), cmd.length());
+}
+
+unsigned int BridgeClass::get(const char *key, uint8_t *value, unsigned int maxlen) {
+  uint8_t cmd[] = {'d'};
+  unsigned int l = transfer(cmd, 1, (uint8_t *)key, strlen(key), value, maxlen);
+  if (l < maxlen)
+    value[l] = 0; // Zero-terminate string
+  return l;
+}
+
+void BridgeClass::crcUpdate(uint8_t c) {
+  
+  CRC = _crc_ccitt_update(CRC, c);
+  //CRC = CRC ^ c;
+  //CRC = (CRC >> 8) + (CRC << 8);
+}
+
+void BridgeClass::crcReset() {
+  CRC = 0xFFFF;
+}
+
+void BridgeClass::crcWrite() {
+  stream.write((char)(CRC >> 8));
+  stream.write((char)(CRC & 0xFF));
+}
+
+bool BridgeClass::crcCheck(uint16_t _CRC) {
+  return CRC == _CRC;
+}
+
+uint16_t BridgeClass::transfer(const uint8_t *buff1, uint16_t len1,
+                 const uint8_t *buff2, uint16_t len2,
+                 const uint8_t *buff3, uint16_t len3,
+                 uint8_t *rxbuff, uint16_t rxlen)
+{
+  uint16_t len = len1 + len2 + len3;
+  uint8_t retries = 0;
+  for ( ; retries<max_retries; retries++, delay(100), dropAll() /* Delay for retransmission */) {
+    // Send packet
+    crcReset();
+    stream.write((char)0xFF);                // Start of packet (0xFF)
+    crcUpdate(0xFF);
+    stream.write((char)index);               // Message index
+    crcUpdate(index);
+    stream.write((char)((len >> 8) & 0xFF)); // Message length (hi)
+    crcUpdate((len >> 8) & 0xFF);
+    stream.write((char)(len & 0xFF));        // Message length (lo)
+    crcUpdate(len & 0xFF);
+    for (uint16_t i=0; i<len1; i++) {  // Payload
+      stream.write((char)buff1[i]);
+      crcUpdate(buff1[i]);
+    }
+    for (uint16_t i=0; i<len2; i++) {  // Payload
+      stream.write((char)buff2[i]);
+      crcUpdate(buff2[i]);
+    }
+    for (uint16_t i=0; i<len3; i++) {  // Payload
+      stream.write((char)buff3[i]);
+      crcUpdate(buff3[i]);
+    }
+    crcWrite();                     // CRC
+  
+    // Wait for ACK in 100ms
+    if (timedRead(100) != 0xFF)
+      continue;
+    crcReset();
+    crcUpdate(0xFF);
+    
+    // Check packet index
+    if (timedRead(5) != index)
+      continue;
+    crcUpdate(index);
+    
+    // Recv len
+    int lh = timedRead(5);
+    if (lh < 0)
+      continue;
+    crcUpdate(lh);
+    int ll = timedRead(5);
+    if (ll < 0)
+      continue;
+    crcUpdate(ll);
+    uint16_t l = lh;
+    l <<= 8;
+    l += ll;
+
+    // Recv data
+    for (uint16_t i=0; i<l; i++) {
+      int c = timedRead(5);
+      if (c < 0)
+        continue;
+      // Cut received data if rxbuffer is too small
+      if (i < rxlen)
+        rxbuff[i] = c;
+      crcUpdate(c);
+    }
+    
+    // Check CRC
+    int crc_hi = timedRead(5);
+    if (crc_hi < 0)
+      continue;
+    int crc_lo = timedRead(5);
+    if (crc_lo < 0)
+      continue;
+    if (!crcCheck((crc_hi<<8)+crc_lo))
+      continue;
+    
+    // Increase index
+    index++;
+    
+    // Return bytes received
+    if (l > rxlen)
+      return rxlen;
+    return l;
+  }
+
+  // Max retries exceeded
+  return TRANSFER_TIMEOUT;
+}
+
+int BridgeClass::timedRead(unsigned int timeout) {
+  int c;
+  unsigned long _startMillis = millis();
+  do {
+    c = stream.read();
+    if (c >= 0) return c;
+  } while(millis() - _startMillis < timeout);
+  return -1;     // -1 indicates timeout
+}
+
+void BridgeClass::dropAll() {
+  while (stream.available() > 0) {
+    stream.read();
+  }
+}
+
+// Bridge instance
+#ifdef __AVR_ATmega32U4__
+  // Leonardo variants (where HardwareSerial is Serial1)
+  SerialBridgeClass Bridge(Serial1);
+#else
+  SerialBridgeClass Bridge(Serial);
+#endif