contiki/core/net/mac/phase.c
adamdunkels 7bab9316da Two major changes:
* Low-power streaming. Experimental support for a low-power mode which
  allows rapid exchange of packets with a 16% duty cycle. Does not
  seem to function correctly yet though.

* Phase locking. When the phase of a neighbor has been detected, the
  sender assumes that the neighbor will keeps it phase and does not
  send more strobes than necessary to hit the receiver's channel
  check - even if the receiver does not acknowledge the reception of
  the strobes when it should have been awake. Instead, the sender
  stops strobing and tries again at a later time.
2010-03-14 22:59:23 +00:00

206 lines
6.8 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 1.4 2010/03/14 22:59:23 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"
#include "sys/clock.h"
#include "lib/memb.h"
#include "net/rime/ctimer.h"
#include "net/rime/queuebuf.h"
#include "dev/watchdog.h"
#include "dev/leds.h"
struct phase_queueitem {
struct ctimer timer;
mac_callback_t mac_callback;
void *mac_callback_ptr;
struct queuebuf *q;
};
#define PHASE_DEFER_THRESHOLD 2
#define PHASE_QUEUESIZE 8
#define MAX_NOACKS 3
MEMB(phase_memb, struct phase_queueitem, PHASE_QUEUESIZE);
#define DEBUG 1
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#define PRINTDEBUG(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#define PRINTDEBUG(...)
#endif
/*---------------------------------------------------------------------------*/
void
phase_update(const struct phase_list *list,
const rimeaddr_t * neighbor, rtimer_clock_t time,
int mac_status)
{
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;
/* If the neighbor didn't reply to us, it may have switched
phase (rebooted). We try a number of transmissions to it
before we drop it from the phase list. */
if(mac_status == MAC_TX_NOACK) {
printf("phase noacks %d\n", e->noacks);
e->noacks++;
if(e->noacks >= MAX_NOACKS) {
list_remove(*list->list, e);
memb_free(&phase_memb, e);
return;
}
} else if(mac_status == MAC_TX_OK) {
e->noacks = 0;
}
/* Make sure this entry is first on the list so subsequent
searches are faster. */
list_remove(*list->list, e);
list_push(*list->list, e);
break;
}
}
/* No matching phase was found, so we allocate a new one. */
if(mac_status == MAC_TX_OK && 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;
e->noacks = 0;
list_push(*list->list, e);
}
}
/*---------------------------------------------------------------------------*/
static void
send_packet(void *ptr)
{
struct phase_queueitem *p = ptr;
queuebuf_to_packetbuf(p->q);
queuebuf_free(p->q);
memb_free(&phase_memb, p);
NETSTACK_RDC.send(p->mac_callback, p->mac_callback_ptr);
}
/*---------------------------------------------------------------------------*/
phase_status_t
phase_wait(struct phase_list *list,
const rimeaddr_t *neighbor, rtimer_clock_t cycle_time,
rtimer_clock_t wait_before,
mac_callback_t mac_callback, void *mac_callback_ptr)
{
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;
clock_time_t ctimewait;
/* 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;
}
ctimewait = (CLOCK_SECOND * (wait - wait_before)) / RTIMER_ARCH_SECOND;
if(ctimewait > PHASE_DEFER_THRESHOLD) {
struct phase_queueitem *p;
p = memb_alloc(&phase_memb);
if(p != NULL) {
p->q = queuebuf_new_from_packetbuf();
if(p->q != NULL) {
p->mac_callback = mac_callback;
p->mac_callback_ptr = mac_callback_ptr;
ctimer_set(&p->timer, ctimewait, send_packet, p);
return PHASE_DEFERRED;
} else {
memb_free(&phase_memb, p);
}
}
}
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)) {
watchdog_periodic();
}
}
return PHASE_SEND_NOW;
}
}
return PHASE_UNKNOWN;
}
/*---------------------------------------------------------------------------*/
void
phase_init(struct phase_list *list)
{
list_init(*list->list);
memb_init(list->memb);
memb_init(&phase_memb);
}
/*---------------------------------------------------------------------------*/