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LibrePilot/flight/OpenPilot/UAVTalk/uavtalk.c
vassilis bc472102b4 OP-4 Flight/Telemetry More bug fixes after testing telemetry 
git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@506 ebee16cc-31ac-478f-84a7-5cbb03baadba
2010-04-16 01:56:08 +00:00

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/**
******************************************************************************
*
* @file uavtalk.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief UAVTalk library, implements to telemetry protocol. See the wiki for more details.
* This library should not be called directly by the application, it is only used by the
* Telemetry module.
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "openpilot.h"
// Private constants
#define TYPE_MASK 0xFC
#define TYPE_VER 0x10
#define TYPE_OBJ (TYPE_VER | 0x00)
#define TYPE_OBJ_REQ (TYPE_VER | 0x01)
#define TYPE_OBJ_ACK (TYPE_VER | 0x02)
#define TYPE_ACK (TYPE_VER | 0x03)
#define HEADER_LENGTH 7 // type (1), object ID (4), instance ID (2, not used in single objects)
#define CHECKSUM_LENGTH 2
#define MAX_PAYLOAD_LENGTH 256
#define MAX_PACKET_LENGTH (HEADER_LENGTH+MAX_PAYLOAD_LENGTH+CHECKSUM_LENGTH)
// Private types
typedef enum {STATE_SYNC, STATE_OBJID, STATE_INSTID, STATE_DATA, STATE_CS} RxState;
// Private variables
static UAVTalkOutputStream outStream;
static xSemaphoreHandle lock;
static xSemaphoreHandle respSema;
static UAVObjHandle respObj;
static uint16_t respInstId;
static uint8_t rxBuffer[MAX_PACKET_LENGTH];
static uint8_t txBuffer[MAX_PACKET_LENGTH];
// Private functions
static uint16_t updateChecksum(uint16_t cs, uint8_t* data, int32_t length);
static int32_t objectTransaction(uint32_t objectId, uint16_t instId, uint8_t type, int32_t timeout);
static int32_t sendObject(UAVObjHandle obj, uint16_t instId, uint8_t type);
static int32_t sendSingleObject(UAVObjHandle obj, uint16_t instId, uint8_t type);
static int32_t receiveObject(uint8_t type, UAVObjHandle obj, uint16_t instId, uint8_t* data, int32_t length);
static void updateAck(UAVObjHandle obj, uint16_t instId);
/**
* Initialize the UAVTalk library
* \param[in] outputStream Function pointer that is called to send a data buffer
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkInitialize(UAVTalkOutputStream outputStream)
{
outStream = outputStream;
lock = xSemaphoreCreateRecursiveMutex();
vSemaphoreCreateBinary(respSema);
xSemaphoreTake(respSema, 0); // reset to zero
return 0;
}
/**
* Request an update for the specified object, on success the object data would have been
* updated by the GCS.
* \param[in] obj Object to update
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] timeout Time to wait for the response, when zero it will return immediately
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkSendObjectRequest(UAVObjHandle obj, uint16_t instId, int32_t timeout)
{
return objectTransaction(obj, instId, TYPE_OBJ_REQ, timeout);
}
/**
* Send the specified object through the telemetry link.
* \param[in] obj Object to send
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] acked Selects if an ack is required (1:ack required, 0: ack not required)
* \param[in] timeoutMs Time to wait for the ack, when zero it will return immediately
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkSendObject(UAVObjHandle obj, uint16_t instId, uint8_t acked, int32_t timeoutMs)
{
// Send object
if (acked == 1)
{
return objectTransaction(obj, instId, TYPE_OBJ_ACK, timeoutMs);
}
else
{
return objectTransaction(obj, instId, TYPE_OBJ, timeoutMs);
}
}
/**
* Execute the requested transaction on an object.
* \param[in] obj Object
* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] type Transaction type
* TYPE_OBJ: send object,
* TYPE_OBJ_REQ: request object update
* TYPE_OBJ_ACK: send object with an ack
* \return 0 Success
* \return -1 Failure
*/
static int32_t objectTransaction(UAVObjHandle obj, uint16_t instId, uint8_t type, int32_t timeoutMs)
{
int32_t respReceived;
// Lock
xSemaphoreTakeRecursive(lock, portMAX_DELAY);
// Send object depending on if a response is needed
if (type == TYPE_OBJ_ACK || type == TYPE_OBJ_REQ)
{
xSemaphoreTake(respSema, 0); // non blocking call to make sure the value is zero (binary sema)
sendObject(obj, instId, type);
respObj = obj;
respInstId = instId;
xSemaphoreGiveRecursive(lock); // need to release lock since the next call will block until a response is received
respReceived = xSemaphoreTake(respSema, timeoutMs/portTICK_RATE_MS); // lock on object until a response is received (or timeout)
// Check if a response was received
if (respReceived == pdFALSE)
{
return -1;
}
else
{
return 0;
}
}
else if (type == TYPE_OBJ)
{
sendObject(obj, instId, TYPE_OBJ);
xSemaphoreGiveRecursive(lock);
return 0;
}
else
{
xSemaphoreGiveRecursive(lock);
return -1;
}
}
/**
* Process an byte from the telemetry stream.
* \param[in] rxbyte Received byte
* \return 0 Success
* \return -1 Failure
*/
int32_t UAVTalkProcessInputStream(uint8_t rxbyte)
{
static uint8_t tmpBuffer[4];
static UAVObjHandle obj;
static uint8_t type;
static uint32_t objId;
static uint16_t instId;
static uint32_t length;
static uint16_t cs, csRx;
static int32_t rxCount;
static RxState state = STATE_SYNC;
// Receive state machine
switch (state) {
case STATE_SYNC:
if ((rxbyte & TYPE_MASK) == TYPE_VER )
{
cs = rxbyte;
type = rxbyte;
state = STATE_OBJID;
rxCount = 0;
}
break;
case STATE_OBJID:
tmpBuffer[rxCount++] = rxbyte;
if (rxCount == 4)
{
// Search for object, if not found reset state machine
objId = (tmpBuffer[3] << 24) | (tmpBuffer[2] << 16) | (tmpBuffer[1] << 8) | (tmpBuffer[0]);
obj = UAVObjGetByID(objId);
if (obj == 0)
{
state = STATE_SYNC;
}
else
{
// Update checksum
cs = updateChecksum(cs, tmpBuffer, 4);
// Determine data length
if (type == TYPE_OBJ_REQ || type == TYPE_ACK)
{
length = 0;
}
else
{
length = UAVObjGetNumBytes(obj);
}
// Check length and determine next state
if (length >= MAX_PAYLOAD_LENGTH)
{
state = STATE_SYNC;
}
else
{
// Check if this is a single instance object (i.e. if the instance ID field is coming next)
if ( UAVObjIsSingleInstance(obj) )
{
// If there is a payload get it, otherwise receive checksum
if (length > 0)
{
state = STATE_DATA;
}
else
{
state = STATE_CS;
}
instId = 0;
rxCount = 0;
}
else
{
state = STATE_INSTID;
rxCount = 0;
}
}
}
}
break;
case STATE_INSTID:
tmpBuffer[rxCount++] = rxbyte;
if (rxCount == 2)
{
instId = (tmpBuffer[1] << 8) | (tmpBuffer[0]);
cs = updateChecksum(cs, tmpBuffer, 2);
rxCount = 0;
// If there is a payload get it, otherwise receive checksum
if (length > 0)
{
state = STATE_DATA;
}
else
{
state = STATE_CS;
}
}
break;
case STATE_DATA:
rxBuffer[rxCount++] = rxbyte;
if (rxCount == length)
{
cs = updateChecksum(cs, rxBuffer, length);
state = STATE_CS;
rxCount = 0;
}
break;
case STATE_CS:
tmpBuffer[rxCount++] = rxbyte;
if (rxCount == 2)
{
csRx = (tmpBuffer[1] << 8) | (tmpBuffer[0]);
if (csRx == cs)
{
xSemaphoreTakeRecursive(lock, portMAX_DELAY);
receiveObject(type, obj, instId, rxBuffer, length);
xSemaphoreGiveRecursive(lock);
}
state = STATE_SYNC;
}
break;
default:
state = STATE_SYNC;
}
// Done
return 0;
}
/**
* Receive an object. This function process objects received through the telemetry stream.
* \param[in] type Type of received message (TYPE_OBJ, TYPE_OBJ_REQ, TYPE_OBJ_ACK, TYPE_ACK)
* \param[in] obj Handle of the received object
* \param[in] instId The instance ID of UAVOBJ_ALL_INSTANCES for all instances.
* \param[in] data Data buffer
* \param[in] length Buffer length
* \return 0 Success
* \return -1 Failure
*/
static int32_t receiveObject(uint8_t type, UAVObjHandle obj, uint16_t instId, uint8_t* data, int32_t length)
{
int32_t ret = 0;
// Process message type
switch (type) {
case TYPE_OBJ:
// All instances, not allowed for OBJ messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Unpack object, if the instance does not exist it will be created!
UAVObjUnpack(obj, instId, data);
// Check if an ack is pending
updateAck(obj, instId);
}
else
{
ret = -1;
}
break;
case TYPE_OBJ_ACK:
// All instances, not allowed for OBJ_ACK messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Unpack object, if the instance does not exist it will be created!
if ( UAVObjUnpack(obj, instId, data) == 0 )
{
// Transmit ACK
sendObject(obj, instId, TYPE_ACK);
}
else
{
ret = -1;
}
}
else
{
ret = -1;
}
break;
case TYPE_OBJ_REQ:
// Send requested object if message is of type OBJ_REQ
sendObject(obj, instId, TYPE_OBJ);
break;
case TYPE_ACK:
// All instances, not allowed for ACK messages
if (instId != UAVOBJ_ALL_INSTANCES)
{
// Check if an ack is pending
updateAck(obj, instId);
}
else
{
ret = -1;
}
break;
default:
ret = -1;
}
// Done
return ret;
}
/**
* Check if an ack is pending on an object and give response semaphore
*/
static void updateAck(UAVObjHandle obj, uint16_t instId)
{
if (respObj == obj && (respInstId == instId || respInstId == UAVOBJ_ALL_INSTANCES))
{
xSemaphoreGive(respSema);
respObj = 0;
}
}
/**
* Send an object through the telemetry link.
* \param[in] obj Object handle to send
* \param[in] instId The instance ID or UAVOBJ_ALL_INSTANCES for all instances
* \param[in] type Transaction type
* \return 0 Success
* \return -1 Failure
*/
static int32_t sendObject(UAVObjHandle obj, uint16_t instId, uint8_t type)
{
uint32_t numInst;
uint32_t n;
// If all instances are requested on a single instance object it is an error
if ( instId == UAVOBJ_ALL_INSTANCES && UAVObjIsSingleInstance(obj) )
{
return -1;
}
// Process message type
if ( type == TYPE_OBJ || type == TYPE_OBJ_ACK )
{
if (instId == UAVOBJ_ALL_INSTANCES)
{
// Get number of instances
numInst = UAVObjGetNumInstances(obj);
// Send all instances
for (n = 0; n < numInst; ++n)
{
sendSingleObject(obj, n, type);
}
return 0;
}
else
{
return sendSingleObject(obj, instId, type);
}
}
else if (type == TYPE_OBJ_REQ)
{
return sendSingleObject(obj, instId, TYPE_OBJ_REQ);
}
else if (type == TYPE_ACK)
{
if ( instId != UAVOBJ_ALL_INSTANCES )
{
return sendSingleObject(obj, instId, TYPE_ACK);
}
else
{
return -1;
}
}
else
{
return -1;
}
}
/**
* Send an object through the telemetry link.
* \param[in] obj Object handle to send
* \param[in] instId The instance ID (can NOT be UAVOBJ_ALL_INSTANCES, use sendObject() instead)
* \param[in] type Transaction type
* \return 0 Success
* \return -1 Failure
*/
static int32_t sendSingleObject(UAVObjHandle obj, uint16_t instId, uint8_t type)
{
int32_t length;
int32_t dataOffset;
uint16_t cs = 0;
uint32_t objId;
// Setup type and object id fields
objId = UAVObjGetID(obj);
txBuffer[0] = type;
txBuffer[1] = (uint8_t)(objId & 0xFF);
txBuffer[2] = (uint8_t)((objId >> 8) & 0xFF);
txBuffer[3] = (uint8_t)((objId >> 16) & 0xFF);
txBuffer[4] = (uint8_t)((objId >> 24) & 0xFF);
// Setup instance ID if one is required
if (UAVObjIsSingleInstance(obj))
{
dataOffset = 5;
}
else
{
txBuffer[5] = (uint8_t)(instId & 0xFF);
txBuffer[6] = (uint8_t)((instId >> 8) & 0xFF);
dataOffset = 7;
}
// Determine data length
if (type == TYPE_OBJ_REQ || type == TYPE_ACK)
{
length = 0;
}
else
{
length = UAVObjGetNumBytes(obj);
}
// Check length
if (length >= MAX_PAYLOAD_LENGTH)
{
return -1;
}
// Copy data (if any)
if (length > 0)
{
if ( UAVObjPack(obj, instId, &txBuffer[dataOffset]) < 0 )
{
return -1;
}
}
// Calculate checksum
cs = 0;
cs = updateChecksum(cs, txBuffer, dataOffset+length);
txBuffer[dataOffset+length] = (uint8_t)(cs & 0xFF);
txBuffer[dataOffset+length+1] = (uint8_t)((cs >> 8) & 0xFF);
// Send buffer
if (outStream!=NULL) (*outStream)(txBuffer, dataOffset+length+CHECKSUM_LENGTH);
// Done
return 0;
}
/**
* Update checksum.
* TODO: Replace with CRC-16
* \param[in] data Data buffer to update checksum on
* \param[in] length Length of buffer
* \return Updated checksum
*/
static uint16_t updateChecksum(uint16_t cs, uint8_t* data, int32_t length)
{
int32_t n;
for (n = 0; n < length; ++n)
{
cs += (uint16_t)data[n];
}
return cs;
}
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