nes-proj/core/net/mac/xmac.c

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/*
* Copyright (c) 2007, 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: xmac.c,v 1.1 2007/04/07 05:43:31 adamdunkels Exp $
*/
/**
* \file
* A simple power saving MAC protocol based on X-MAC [SenSys 2006]
* \author
* Adam Dunkels <adam@sics.se>
*/
#include "sys/pt.h"
#include "net/mac/xmac.h"
#include "sys/rtimer.h"
#include "dev/leds.h"
#include "net/rime.h"
#include "dev/radio.h"
struct powercycle {
struct pt pt;
struct rtimer rt;
rtimer_clock_t ontime, offtime;
int num_strobes;
};
struct xmac_hdr {
rimeaddr_t receiver;
};
static struct rtimer rt;
static struct pt pt;
#define BASE_TIME (RTIMER_ARCH_SECOND / 100)
#define OFF_TIME BASE_TIME * 10
#define ON_TIME BASE_TIME
#define STROBE_WAIT_TIME ON_TIME / 10
static volatile unsigned char should_be_awake = 0;
static volatile unsigned char radio_is_on = 0;
static int (*send_func)(const u8_t *buf, u8_t len);
#undef LEDS_ON
#undef LEDS_OFF
#undef LEDS_TOGGLE
#define DEBUG 0
#if DEBUG
#define LEDS_ON(x) leds_on(x)
#define LEDS_OFF(x) leds_off(x)
#define LEDS_TOGGLE(x) leds_toggle(x)
#else
#define LEDS_ON(x)
#define LEDS_OFF(x)
#define LEDS_TOGGLE(x)
#endif
/*---------------------------------------------------------------------------*/
static void
powercycle(struct rtimer *t, void *ptr)
{
static int awake_periods = 0;
PT_BEGIN(&pt);
while(1) {
if(should_be_awake == 0) {
awake_periods = 0;
radio_off();
radio_is_on = 0;
LEDS_OFF(LEDS_RED);
} else {
awake_periods++;
/* if(awake_periods > 4) {
awake_periods = 0;
should_be_awake = 0;
}*/
}
rtimer_set(t, RTIMER_TIME(t) + OFF_TIME, 1, powercycle, ptr);
PT_YIELD(&pt);
if(radio_is_on == 0) {
radio_on();
radio_is_on = 1;
LEDS_ON(LEDS_RED);
}
rtimer_set(t, RTIMER_TIME(t) + ON_TIME, 1, powercycle, ptr);
PT_YIELD(&pt);
}
PT_END(&pt);
}
/*---------------------------------------------------------------------------*/
void
xmac_init(void)
{
radio_is_on = 0;
should_be_awake = 0;
PT_INIT(&pt);
rtimer_set(&rt, RTIMER_NOW() + OFF_TIME, 1, powercycle, NULL);
rime_set_output(xmac_send);
}
/*---------------------------------------------------------------------------*/
void
xmac_send(void)
{
rtimer_clock_t t0, t1;
int strobes;
/* printf("xmac_send\n");*/
rimebuf_hdralloc(sizeof(struct xmac_hdr));
rimebuf_compact();
should_be_awake = 1;
while(!radio_is_on);
t0 = RTIMER_NOW();
strobes = 0;
do {
struct xmac_hdr msg;
rtimer_clock_t t;
t = RTIMER_NOW();
LEDS_TOGGLE(LEDS_GREEN);
msg.receiver.u16[0] = 0;
if(send_func) {
send_func((const u8_t *)&msg, sizeof(struct xmac_hdr));
}
while(RTIMER_CLOCK_LT(RTIMER_NOW(), t + STROBE_WAIT_TIME));
/* printf("Strobe %d\n", strobes);*/
++strobes;
} while(RTIMER_CLOCK_LT(RTIMER_NOW(), t0 + OFF_TIME + ON_TIME));
if(send_func) {
send_func(rimebuf_hdrptr(), rimebuf_totlen());
}
LEDS_OFF(LEDS_GREEN);
should_be_awake = 0;
/* printf("xmac_send after\n");*/
}
/*---------------------------------------------------------------------------*/
void
xmac_set_sendfunc(int (*f)(const u8_t *, u8_t))
{
send_func = f;
}
/*---------------------------------------------------------------------------*/
void
xmac_input(void)
{
struct xmac_hdr *hdr = rimebuf_dataptr();
rimebuf_hdrreduce(sizeof(struct xmac_hdr));
if(rimeaddr_cmp(&hdr->receiver, &rimeaddr_node_addr)) {
/* XXX Send an ACK and wait for packet . */
should_be_awake = 1;
} else if(rimeaddr_cmp(&hdr->receiver, &rimeaddr_null)) {
/* Wait for the actual packet to arrive. */
should_be_awake = 1;
} else {
/* Go back to sleep. */
should_be_awake = 0;
}
if(rimebuf_totlen() > 0) {
/* We have received the final packet, so we can go back to being
asleep. */
should_be_awake = 0;
rime_input();
}
}
/*---------------------------------------------------------------------------*/