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// $Id: AMQueueImplP.nc,v 1.11 2010-06-29 22:07:56 scipio Exp $
/*
* Copyright (c) 2005 Stanford University. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
* - Neither the name of the copyright holders nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* An AM send queue that provides a Service Instance pattern for
* formatted packets and calls an underlying AMSend in a round-robin
* fashion. Used to share L2 bandwidth between different communication
* clients.
*
* @author Philip Levis
* @date Jan 16 2006
*/
#include "AM.h"
generic module AMQueueImplP(int numClients) @safe() {
provides interface Send[uint8_t client];
uses{
interface AMSend[am_id_t id];
interface AMPacket;
interface Packet;
}
}
implementation {
typedef struct {
message_t* ONE_NOK msg;
} queue_entry_t;
uint8_t current = numClients; // mark as empty
queue_entry_t queue[numClients];
uint8_t cancelMask[numClients/8 + 1];
void tryToSend();
void nextPacket() {
uint8_t i;
current = (current + 1) % numClients;
for(i = 0; i < numClients; i++) {
if((queue[current].msg == NULL) ||
(cancelMask[current/8] & (1 << current%8)))
{
current = (current + 1) % numClients;
}
else {
break;
}
}
if(i >= numClients) current = numClients;
}
/**
* Accepts a properly formatted AM packet for later sending.
* Assumes that someone has filled in the AM packet fields
* (destination, AM type).
*
* @param msg - the message to send
* @param len - the length of the payload
*
*/
command error_t Send.send[uint8_t clientId](message_t* msg,
uint8_t len) {
if (clientId >= numClients) {
return FAIL;
}
if (queue[clientId].msg != NULL) {
return EBUSY;
}
dbg("AMQueue", "AMQueue: request to send from %hhu (%p): passed checks\n", clientId, msg);
queue[clientId].msg = msg;
call Packet.setPayloadLength(msg, len);
if (current >= numClients) { // queue empty
error_t err;
am_id_t amId = call AMPacket.type(msg);
am_addr_t dest = call AMPacket.destination(msg);
dbg("AMQueue", "%s: request to send from %hhu (%p): queue empty\n", __FUNCTION__, clientId, msg);
current = clientId;
err = call AMSend.send[amId](dest, msg, len);
if (err != SUCCESS) {
dbg("AMQueue", "%s: underlying send failed.\n", __FUNCTION__);
current = numClients;
queue[clientId].msg = NULL;
}
return err;
}
else {
dbg("AMQueue", "AMQueue: request to send from %hhu (%p): queue not empty\n", clientId, msg);
}
return SUCCESS;
}
task void CancelTask() {
uint8_t i,j,mask,last;
message_t *msg;
for(i = 0; i < numClients/8 + 1; i++) {
if(cancelMask[i]) {
for(mask = 1, j = 0; j < 8; j++) {
if(cancelMask[i] & mask) {
last = i*8 + j;
msg = queue[last].msg;
queue[last].msg = NULL;
cancelMask[i] &= ~mask;
signal Send.sendDone[last](msg, ECANCEL);
}
mask <<= 1;
}
}
}
}
command error_t Send.cancel[uint8_t clientId](message_t* msg) {
if (clientId >= numClients || // Not a valid client
queue[clientId].msg == NULL || // No packet pending
queue[clientId].msg != msg) { // Not the right packet
return FAIL;
}
if(current == clientId) {
am_id_t amId = call AMPacket.type(msg);
error_t err = call AMSend.cancel[amId](msg);
return err;
}
else {
cancelMask[clientId/8] |= 1 << clientId % 8;
post CancelTask();
return SUCCESS;
}
}
void sendDone(uint8_t last, message_t * ONE msg, error_t err) {
queue[last].msg = NULL;
tryToSend();
signal Send.sendDone[last](msg, err);
}
task void errorTask() {
sendDone(current, queue[current].msg, FAIL);
}
// NOTE: Increments current!
void tryToSend() {
nextPacket();
if (current < numClients) { // queue not empty
error_t nextErr;
message_t* nextMsg = queue[current].msg;
am_id_t nextId = call AMPacket.type(nextMsg);
am_addr_t nextDest = call AMPacket.destination(nextMsg);
uint8_t len = call Packet.payloadLength(nextMsg);
nextErr = call AMSend.send[nextId](nextDest, nextMsg, len);
if(nextErr != SUCCESS) {
post errorTask();
}
}
}
event void AMSend.sendDone[am_id_t id](message_t* msg, error_t err) {
// Bug fix from John Regehr: if the underlying radio mixes things
// up, we don't want to read memory incorrectly. This can occur
// on the mica2.
// Note that since all AM packets go through this queue, this
// means that the radio has a problem. -pal
if (current >= numClients) {
return;
}
if(queue[current].msg == msg) {
sendDone(current, msg, err);
}
else {
dbg("PointerBug", "%s received send done for %p, signaling for %p.\n",
__FUNCTION__, msg, queue[current].msg);
}
}
command uint8_t Send.maxPayloadLength[uint8_t id]() {
return call AMSend.maxPayloadLength[0]();
}
command void* Send.getPayload[uint8_t id](message_t* m, uint8_t len) {
return call AMSend.getPayload[0](m, len);
}
default event void Send.sendDone[uint8_t id](message_t* msg, error_t err) {
// Do nothing
}
default command error_t AMSend.send[uint8_t id](am_addr_t am_id, message_t* msg, uint8_t len) {
return FAIL;
}
}
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