117 lines
4.4 KiB
C
117 lines
4.4 KiB
C
/*
|
|
* Copyright (c) 2010, Swedish Institute of Computer Science.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. 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.
|
|
* 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
|
|
*
|
|
* This file is part of the Contiki operating system.
|
|
*
|
|
* $Id: phase.c,v 1.1 2010/02/18 20:58:59 adamdunkels Exp $
|
|
*/
|
|
|
|
/**
|
|
* \file
|
|
* Common functionality for phase optimization in duty cycling radio protocols
|
|
* \author
|
|
* Adam Dunkels <adam@sics.se>
|
|
*/
|
|
|
|
#include "net/mac/phase.h"
|
|
#include "net/rime/packetbuf.h"
|
|
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
phase_register(const struct phase_list *list,
|
|
const rimeaddr_t * neighbor, rtimer_clock_t time)
|
|
{
|
|
struct phase *e;
|
|
|
|
/* If we have an entry for this neighbor already, we renew it. */
|
|
for(e = list_head(*list->list); e != NULL; e = e->next) {
|
|
if(rimeaddr_cmp(neighbor, &e->neighbor)) {
|
|
e->time = time;
|
|
break;
|
|
}
|
|
}
|
|
/* No matching phase was found, so we allocate a new one. */
|
|
if(e == NULL) {
|
|
e = memb_alloc(list->memb);
|
|
if(e == NULL) {
|
|
/* We could not allocate memory for this phase, so we drop
|
|
the last item on the list and reuse it for our phase. */
|
|
e = list_chop(*list->list);
|
|
}
|
|
rimeaddr_copy(&e->neighbor, neighbor);
|
|
e->time = time;
|
|
list_push(*list->list, e);
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
phase_wait(struct phase_list *list,
|
|
const rimeaddr_t *neighbor, rtimer_clock_t cycle_time,
|
|
rtimer_clock_t wait_before)
|
|
{
|
|
struct phase *e;
|
|
|
|
/* We go through the list of phases to find if we have recorded
|
|
an phase with this particular neighbor. If so, we can compute
|
|
the time for the next expected phase and setup a ctimer to
|
|
switch on the radio just before the phase. */
|
|
for(e = list_head(*list->list); e != NULL; e = e->next) {
|
|
const rimeaddr_t *neighbor = packetbuf_addr(PACKETBUF_ADDR_RECEIVER);
|
|
|
|
if(rimeaddr_cmp(neighbor, &e->neighbor)) {
|
|
rtimer_clock_t wait, now, expected;
|
|
|
|
/* We expect phases to happen every CYCLE_TIME time
|
|
units. The next expected phase is at time e->time +
|
|
CYCLE_TIME. To compute a relative offset, we subtract
|
|
with clock_time(). Because we are only interested in turning
|
|
on the radio within the CYCLE_TIME period, we compute the
|
|
waiting time with modulo CYCLE_TIME. */
|
|
|
|
now = RTIMER_NOW();
|
|
wait = (rtimer_clock_t)((e->time - now) & (cycle_time - 1));
|
|
if(wait < wait_before) {
|
|
wait += cycle_time;
|
|
}
|
|
expected = now + wait - wait_before;
|
|
if(!RTIMER_CLOCK_LT(expected, now)) {
|
|
/* Wait until the receiver is expected to be awake */
|
|
while(RTIMER_CLOCK_LT(RTIMER_NOW(), expected));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|
|
void
|
|
phase_init(struct phase_list *list)
|
|
{
|
|
list_init(*list->list);
|
|
memb_init(list->memb);
|
|
}
|
|
/*---------------------------------------------------------------------------*/
|