nes-proj/core/dev/cc2420.c
bg- 478953dcf4 * Randomised backoff when broadcasting.
* Only warn about rxfifo overflows when sending.

* More intricate tests to verify if transmission really started.
2007-04-04 11:46:10 +00:00

662 lines
16 KiB
C

/*
* Copyright (c) 2005, 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: cc2420.c,v 1.11 2007/04/04 11:46:10 bg- Exp $
*/
/*
* This code is almost device independent and should be easy to port.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "contiki.h"
#if defined(__AVR__)
#include <avr/io.h>
#elif defined(__MSP430__)
#include <io.h>
#endif
#include "net/uip.h"
#define BUF ((struct uip_tcpip_hdr *)&uip_buf[UIP_LLH_LEN])
#include "dev/leds.h"
#include "dev/spi.h"
#include "dev/cc2420.h"
#include "dev/cc2420_const.h"
#if 0
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...) do {} while (0)
#endif
PROCESS(cc2420_process, "CC2420 driver");
PROCESS(cc2420_retransmit_process, "CC2420 retransmit process");
int cc2420_resend(void); /* Not yet exported. */
static void neigbour_update(u16_t mac, int retransmissions);
signed char cc2420_last_rssi;
u8_t cc2420_last_correlation;
static u8_t receive_on;
volatile u8_t cc2420_ack_received; /* Naive ACK management. */
static u8_t last_used_seq;
static u16_t last_correspondent;
/* Radio stuff in network byte order. */
static u16_t pan_id;
unsigned
cc2420_getreg(enum cc2420_register regname)
{
unsigned reg;
int s = splhigh();
FASTSPI_GETREG(regname, reg);
splx(s);
return reg;
}
void
cc2420_setreg(enum cc2420_register regname, unsigned value)
{
int s = splhigh();
FASTSPI_SETREG(regname, value);
splx(s);
}
void
cc2420_strobe(enum cc2420_register regname)
{
int s = splhigh();
FASTSPI_STROBE(regname);
splx(s);
}
unsigned
cc2420_status(void)
{
u8_t status;
int s = splhigh();
FASTSPI_UPD_STATUS(status);
splx(s);
return status;
}
#define AUTOACK (1 << 4)
#define RXFIFO_PROTECTION (1 << 9)
#define CORR_THR(n) (((n) & 0x1f) << 6)
#define FIFOP_THR(n) ((n) & 0x7f)
#define RXBPF_LOCUR (1 << 13);
void
cc2420_init(void)
{
u16_t reg;
{
int s = splhigh();
__cc2420_arch_init(); /* Initalize ports and SPI. */
DISABLE_FIFOP_INT();
FIFOP_INT_INIT();
splx(s);
}
/* Turn on voltage regulator and reset. */
SET_VREG_ACTIVE();
//clock_delay(250); OK
SET_RESET_ACTIVE();
clock_delay(127);
SET_RESET_INACTIVE();
//clock_delay(125); OK
/* Turn on the crystal oscillator. */
cc2420_strobe(CC2420_SXOSCON);
/* Turn on automatic packet acknowledgment. */
reg = cc2420_getreg(CC2420_MDMCTRL0);
reg |= AUTOACK;
cc2420_setreg(CC2420_MDMCTRL0, reg);
/* Change default values as recomended in the data sheet, */
/* correlation threshold = 20, RX bandpass filter = 1.3uA. */
cc2420_setreg(CC2420_MDMCTRL1, CORR_THR(20));
reg = cc2420_getreg(CC2420_RXCTRL1);
reg |= RXBPF_LOCUR;
cc2420_setreg(CC2420_RXCTRL1, reg);
/* Set the FIFOP threshold to maximum. */
cc2420_setreg(CC2420_IOCFG0, FIFOP_THR(127));
/* Turn off "Security enable" (page 32). */
reg = cc2420_getreg(CC2420_SECCTRL0);
reg &= ~RXFIFO_PROTECTION;
cc2420_setreg(CC2420_SECCTRL0, reg);
cc2420_set_chan_pan_addr(11, 0xffff, 0x0000, NULL);
}
int
cc2420_send_data_ack(u16_t mac)
{
struct hdr_802_15 h;
PRINTF("send_data_ack to %u.%u\n", mac & 0xff, mac >> 8);
h.len = MAC_HDR_LEN + 2; /* Including footer[2]. */
h.fc0 = FC0_TYPE_DATA | FC0_INTRA_PAN;
h.fc1 = FC1_DST_16 | FC1_SRC_16;
h.src = uip_hostaddr.u16[1];
h.dst = mac;
return cc2420_send(&h, 10, NULL, 0);
}
int
cc2420_send(struct hdr_802_15 *hdr, u8_t hdr_len,
const u8_t *payload, u8_t payload_len)
{
u8_t spiStatusByte;
int s;
/* struct hdr_802_15::len shall *not* be counted, thus the -1.
* 2 == sizeof(footer).
*/
if (((hdr_len - 1) + payload_len + 2) > MAX_PACKET_LEN)
return -1;
/* This code uses the CC2420 CCA (Clear Channel Assessment) to
* implement Carrier Sense Multiple Access with Collision Avoidance
* (CSMA-CA) and requires the receiver to be enabled and ready.
*/
if (!receive_on)
return -2;
/* Wait for previous transmission to finish and RSSI. */
do {
spiStatusByte = cc2420_status();
if (!(spiStatusByte & BV(CC2420_RSSI_VALID))) /* RSSI needed by CCA */
continue;
} while (spiStatusByte & BV(CC2420_TX_ACTIVE));
hdr->dst_pan = pan_id; /* Not at fixed position! xxx/bg */
last_correspondent = hdr->dst; /* Not dst either. */
last_used_seq++;
hdr->seq = last_used_seq;
cc2420_ack_received = 0;
/* Write packet to TX FIFO, appending FCS if AUTOCRC is enabled. */
cc2420_strobe(CC2420_SFLUSHTX); /* Cancel send that never started. */
s = splhigh();
FASTSPI_WRITE_FIFO(hdr, hdr_len);
FASTSPI_WRITE_FIFO(payload, payload_len);
splx(s);
if (hdr->dst == 0xffff) {
int i;
for (i = 0; i < 3; i++) {
static unsigned delaymask[] = { 1024-1, 2048-1, 4096-1 };
if (cc2420_resend() >= 0)
return 0;
PRINTF("resend i=%d\n", i);
clock_delay(rand() & delaymask[i]);
}
} else {
process_post(&cc2420_retransmit_process,
PROCESS_EVENT_MSG,
(void *)(unsigned)last_used_seq);
}
return cc2420_resend(); /* Send stuff from FIFO. */
}
/*
* Request packet to be sent using CSMA-CA. Requires that RSSI is
* valid.
*
* Return -3 on failure.
*/
int
cc2420_resend(void)
{
unsigned i;
if (FIFOP_IS_1 && !FIFO_IS_1) {
/* RXFIFO overflow, send on retransmit. */
PRINTF("rxfifo overflow!\n");
// return -4;
}
/* The TX FIFO can only hold one packet! Make sure to not overrun
* FIFO by waiting for transmission to start here and synchronizing
* with the CC2420_TX_ACTIVE check in cc2420_send.
*
* Note that we may have to wait up to 320 us (20 symbols) before
* transmission starts.
*/
#ifdef TMOTE_SKY
#define LOOP_20_SYMBOLS 100 /* 326us (msp430 @ 2.4576MHz) */
#elif __AVR__
#define LOOP_20_SYMBOLS 500 /* XXX */
#endif
if (CCA_IS_1) {
cc2420_strobe(CC2420_STXONCCA);
for (i = LOOP_20_SYMBOLS; i > 0; i--)
if (SFD_IS_1) {
if (cc2420_status() & BV(CC2420_TX_ACTIVE))
return 0; /* Transmission has started. */
else
break; /* We must be receiving. */
}
}
return -3; /* Transmission never started! */
}
void
cc2420_off(void)
{
u8_t spiStatusByte;
if (receive_on == 0)
return;
receive_on = 0;
/* Wait for transmission to end before turning radio off. */
do {
spiStatusByte = cc2420_status();
} while (spiStatusByte & BV(CC2420_TX_ACTIVE));
cc2420_strobe(CC2420_SRFOFF);
DISABLE_FIFOP_INT();
}
void
cc2420_on(void)
{
if (receive_on)
return;
receive_on = 1;
cc2420_strobe(CC2420_SRXON);
cc2420_strobe(CC2420_SFLUSHRX);
ENABLE_FIFOP_INT();
}
void
cc2420_set_chan_pan_addr(unsigned channel, /* 11 - 26 */
unsigned pan,
unsigned addr,
const u8_t *ieee_addr)
{
/*
* Subtract the base channel (11), multiply by 5, which is the
* channel spacing. 357 is 2405-2048 and 0x4000 is LOCK_THR = 1.
*/
u8_t spiStatusByte;
u16_t f = channel;
int s;
f = 5*(f - 11) + 357 + 0x4000;
/*
* Writing RAM requires crystal oscillator to be stable.
*/
do {
spiStatusByte = cc2420_status();
} while (!(spiStatusByte & (BV(CC2420_XOSC16M_STABLE))));
pan_id = pan;
cc2420_setreg(CC2420_FSCTRL, f);
s = splhigh();
FASTSPI_WRITE_RAM_LE(&pan, CC2420RAM_PANID, 2, f);
FASTSPI_WRITE_RAM_LE(&addr, CC2420RAM_SHORTADDR, 2, f);
if (ieee_addr != NULL)
FASTSPI_WRITE_RAM_LE(ieee_addr, CC2420RAM_IEEEADDR, 8, f);
splx(s);
}
static volatile u8_t rx_fifo_remaining_bytes;
static struct hdr_802_15 h;
/*
* Interrupt either leaves frame intact in FIFO or reads *only* the
* MAC header and sets rx_fifo_remaining_bytes.
*
* In order to quickly empty the FIFO ack processing is done at
* interrupt priority rather than poll priority.
*/
int
__cc2420_intr(void)
{
u8_t length;
const u8_t *const ack_footer = (u8_t *)&h.dst_pan;
CLEAR_FIFOP_INT();
if (spi_busy || rx_fifo_remaining_bytes > 0) {
/* SPI bus hardware is currently used elsewhere (UART0 or I2C bus)
* or we already have a packet in the works and will have to defer
* interrupt processing of this packet in a fake interrupt.
*/
process_poll(&cc2420_process);
return 1;
}
FASTSPI_READ_FIFO_BYTE(length);
if (length > MAX_PACKET_LEN) {
/* Oops, we must be out of sync. */
FASTSPI_STROBE(CC2420_SFLUSHRX);
FASTSPI_STROBE(CC2420_SFLUSHRX);
return 0;
}
h.len = length;
if (length < ACK_PACKET_LEN) {
FASTSPI_READ_FIFO_GARBAGE(length); /* Rubbish */
return 0;
}
FASTSPI_READ_FIFO_NO_WAIT(&h.fc0, 5); /* fc0, fc1, seq, dst_pan */
/* Is this an ACK packet? */
if (length == ACK_PACKET_LEN && (h.fc0 & FC0_TYPE_MASK) == FC0_TYPE_ACK) {
if (ack_footer[1] & FOOTER1_CRC_OK) {
if (h.seq == last_used_seq) { /* Matching ACK number? */
cc2420_ack_received = 1;
process_poll(&cc2420_retransmit_process);
#if 0
cc2420_last_rssi = ack_footer[0];
cc2420_last_correlation = ack_footer[1] & FOOTER1_CORRELATION;
#endif
}
}
return 1;
}
if (length < (MAC_HDR_LEN + 2)) {
FASTSPI_READ_FIFO_GARBAGE(length - 5);
return 0;
}
FASTSPI_READ_FIFO_NO_WAIT(&h.dst, 4); /* dst and src */
/* The payload and footer is now left in the RX FIFO and will be
* picked up asynchronously at poll priority in the cc2420_process
* below.
*/
rx_fifo_remaining_bytes = length - MAC_HDR_LEN;
process_poll(&cc2420_process);
return 1;
}
PROCESS_THREAD(cc2420_process, ev, data)
{
PROCESS_BEGIN();
process_start(&cc2420_retransmit_process, NULL);
while (1) {
unsigned len;
int s;
PROCESS_YIELD();
len = rx_fifo_remaining_bytes;
if (len > 0) {
/* Read payload and two bytes of footer */
if ((len - 2) > (UIP_BUFSIZE - UIP_LLH_LEN) || len < 2) {
PRINTF("cc2420_process too big len=%d\n", len);
s = splhigh();
FASTSPI_READ_FIFO_GARBAGE(len);
rx_fifo_remaining_bytes = 0; /* RX FIFO emptied! */
splx(s);
len = 0;
} else {
u8_t footer[2];
uip_len = 0;
s = splhigh();
FASTSPI_READ_FIFO_NO_WAIT(&uip_buf[UIP_LLH_LEN], len - 2);
FASTSPI_READ_FIFO_NO_WAIT(footer, 2);
rx_fifo_remaining_bytes = 0; /* RX FIFO emptied! */
splx(s);
if (footer[1] & FOOTER1_CRC_OK) {
cc2420_last_rssi = footer[0];
cc2420_last_correlation = footer[1] & FOOTER1_CORRELATION;
if ((h.fc0 & FC0_TYPE_MASK) == FC0_TYPE_DATA)
uip_len = len - 2;
}
}
}
/* Clean up in case of FIFO overflow! This happens for every full
* length frame and is signaled by FIFOP = 1 and FIFO = 0.
*/
if (FIFOP_IS_1 && !FIFO_IS_1) {
cc2420_strobe(CC2420_SFLUSHRX);
cc2420_strobe(CC2420_SFLUSHRX);
}
if (FIFOP_IS_1) {
s = splhigh();
__cc2420_intr(); /* Fake interrupt! */
splx(s);
}
if (len == 2) { /* A DATA ACK packet. */
if (last_correspondent == h.src)
cc2420_ack_received = 1;
neigbour_update(h.src, 0);
} else if (len > 2 && uip_len > 0
&& uip_len == (((u16_t)(BUF->len[0]) << 8) + BUF->len[1])) {
/*
* If we are the unique receiver send DATA ACK.
*/
if (h.dst == 0xffff
&& uip_ipaddr_cmp(&BUF->destipaddr, &uip_hostaddr))
cc2420_send_data_ack(h.src);
leds_toggle(LEDS_GREEN);
tcpip_input();
leds_toggle(LEDS_GREEN);
}
}
PROCESS_END();
}
unsigned neigbour_find(u16_t mac);
/* Must be atleast 2 ticks and larger than 4ms. */
#define RETRANSMIT_TIMEOUT 2 /* 31.25ms @ 64Hz */
#define MAX_RETRANSMISSIONS 3
PROCESS_THREAD(cc2420_retransmit_process, ev, data)
{
static u8_t seq, n;
static struct etimer etimer;
PROCESS_BEGIN();
while (1) {
PROCESS_WAIT_UNTIL(ev == PROCESS_EVENT_MSG);
seq = (unsigned)data;
n = 0;
do {
etimer_set(&etimer, RETRANSMIT_TIMEOUT);
PROCESS_WAIT_UNTIL(etimer_expired(&etimer) || ev == PROCESS_EVENT_POLL);
if (ev == PROCESS_EVENT_POLL) {
etimer_stop(&etimer);
break;
} else if (seq != last_used_seq)
break; /* Transmitting different packet. */
else if (n < MAX_RETRANSMISSIONS) {
cc2420_resend();
n++;
PRINTF("RETRANS %d\n", n);
} else {
break;
}
} while (1);
neigbour_update(last_correspondent, n);
#if 0
#define CORRELATION_2_X(c) (((c) < 48) ? 0 : ((c) - 48))
PRINTF("%04x %2d %2d %2u %u\n",
last_correspondent, n,
RSSI_2_ED(cc2420_last_rssi),
CORRELATION_2_X(cc2420_last_correlation),
clock_time());
#endif
}
PROCESS_END();
}
/*
* Retransmissions are negexp(alfa=0.5) weighted and stored as 4-bit
* fixnums with 2 binals (binary decimals).
*/
#define SCALE_RETRANS 4
#define SCALE_RETRANS_THRESHOLD (3*4)
#define MAX_SCALE_RETRANS 15
/*
* Expiration timestamps are 4-bits wide, in units of 4 seconds, and
* relative to cc2420_check_remote::toff.
*/
#define SCALE_DIV_EXPIRE 4
#define MAX_EXPIRE 15
#define AGE_INTERVAL 5 /* 20 seconds */
struct cc2420_neigbour neigbours[NNEIGBOURS];
/*
* Double hash into 3 different positions using a constand step. If we
* don't find a match, return a pointer to the oldest entry and use
* this position for insertion.
*/
static struct cc2420_neigbour *
lookup(unsigned mac)
{
unsigned h = (mac + (mac>>8)) % NNEIGBOURS;
#define next(h) (h += step, (h >= NNEIGBOURS) ? (h - NNEIGBOURS) : h)
if (neigbours[h].mac == mac) /* FOUND1 */
return &neigbours[h];
else {
unsigned minexp = h;
const unsigned step = ((mac>>9)&0x3) + 1;
h = next(h);
if (neigbours[h].mac == mac) /* FOUND2 */
return &neigbours[h];
else {
if (neigbours[h].expire < neigbours[minexp].expire) minexp = h;
h = next(h);
if (neigbours[h].mac == mac) /* FOUND3 */
return &neigbours[h];
else {
if (neigbours[h].expire < neigbours[minexp].expire) minexp = h;
return &neigbours[minexp];
}
}
}
}
static void
neigbour_update(u16_t mac, int nretrans)
{
struct cc2420_neigbour *t;
/* Always scale nretrans by constant factor. */
if (nretrans == MAX_RETRANSMISSIONS)
nretrans = MAX_SCALE_RETRANS;
else
nretrans *= SCALE_RETRANS; /* xxx/bg overflow! */
t = lookup(mac);
if (t->mac != mac) {
t->mac = mac;
t->nretrans = nretrans;
} else {
if ((t->nretrans + nretrans)/2 > MAX_SCALE_RETRANS)
t->nretrans = MAX_SCALE_RETRANS;
else
t->nretrans = (t->nretrans + nretrans)/2;
}
t->expire = MAX_EXPIRE;
return;
}
void
cc2420_recv_ok(uip_ipaddr_t *from)
{
neigbour_update(from->u16[1], 0);
}
/*
* +1: remote
* 0: local
* -1: unknown
*/
int
cc2420_check_remote(u16_t mac)
{
struct cc2420_neigbour *t;
/*
* Age neigbour table every 5*SCALE_DIV_EXPIRE=20 seconds.
*/
static clock_time_t toff;
unsigned now = ((clock_time() - toff)/CLOCK_SECOND)/SCALE_DIV_EXPIRE;
if (now >= AGE_INTERVAL) {
unsigned i;
for (i = 0; i < NNEIGBOURS; i++)
if (neigbours[i].expire >= now)
neigbours[i].expire -= now;
else
neigbours[i].mac = 0xffff; /* expired! */
toff = clock_time();
}
t = lookup(mac);
if (t->mac != mac)
return -1; /* unknown */
else if (t->nretrans >= SCALE_RETRANS_THRESHOLD)
return +1; /* remote */
else
return 0; /* local */
}