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103 lines
3.0 KiB
C
103 lines
3.0 KiB
C
/**
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* cc2420_rx.c - Implementation of receiving cc2420 functions.
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* Copyright (C) 2013 Milan Babel <babel@inf.fu-berlin.de>
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* Copyright (C) 2014 Kévin Roussel <Kevin.Roussel@inria.fr>
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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#include <stdio.h>
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#include "cc2420.h"
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#include "cc2420_settings.h"
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#include "cc2420_arch.h"
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#include "cc2420_spi.h"
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#include "ieee802154_frame.h"
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#include "kernel_types.h"
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#include "transceiver.h"
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#include "msg.h"
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#define ENABLE_DEBUG (0)
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#include "debug.h"
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/* circular buffer for incoming 802.15.4 packets */
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cc2420_packet_t cc2420_rx_buffer[CC2420_RX_BUF_SIZE];
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volatile uint8_t rx_buffer_next; /* index of next free cell in RX buffer */
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/* pointer to the callback low-level function for packet reception */
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static receive_802154_packet_callback_t recv_func = NULL;
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void cc2420_set_recv_callback(receive_802154_packet_callback_t recv_cb)
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{
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recv_func = recv_cb;
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}
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void cc2420_rx_handler(void)
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{
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uint8_t pkt_len, pkt_lqi;
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int8_t pkt_rssi;
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bool crc_ok;
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/* read length */
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cc2420_read_fifo(&pkt_len, 1);
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/* read packet's raw payload */
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uint8_t buf[pkt_len - 2];
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cc2420_read_fifo(buf, pkt_len - 2);
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/* read rssi, lqi and crc */
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cc2420_read_fifo((uint8_t *) &pkt_rssi, 1);
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cc2420_read_fifo(&pkt_lqi, 1);
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crc_ok = ((pkt_lqi & 0x80) != 0);
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pkt_lqi &= 0x7F;
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if (!crc_ok) {
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DEBUG("Got packet with invalid crc.\n");
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return;
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}
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/* low-level reception mechanism (for MAC layer, among others) */
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if (recv_func != NULL) {
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recv_func(buf, pkt_len - 2, pkt_rssi, pkt_lqi, crc_ok);
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}
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/* decode received packet */
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cc2420_rx_buffer[rx_buffer_next].length = pkt_len;
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cc2420_rx_buffer[rx_buffer_next].rssi = pkt_rssi;
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cc2420_rx_buffer[rx_buffer_next].lqi = pkt_lqi;
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cc2420_rx_buffer[rx_buffer_next].crc = (crc_ok ? 1 : 0);
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ieee802154_frame_read(buf,
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&cc2420_rx_buffer[rx_buffer_next].frame,
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cc2420_rx_buffer[rx_buffer_next].length);
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/* follow-up to transceiver module if adequate */
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if (cc2420_rx_buffer[rx_buffer_next].frame.fcf.frame_type != IEEE_802154_ACK_FRAME) {
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#if ENABLE_DEBUG
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ieee802154_frame_print_fcf_frame(&cc2420_rx_buffer[rx_buffer_next].frame);
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#endif
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/* notify transceiver thread if any */
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if (transceiver_pid != KERNEL_PID_UNDEF) {
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msg_t m;
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m.type = (uint16_t) RCV_PKT_CC2420;
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m.content.value = rx_buffer_next;
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msg_send_int(&m, transceiver_pid);
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}
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}
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#if ENABLE_DEBUG
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else {
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DEBUG("GOT ACK for SEQ %u\n", cc2420_rx_buffer[rx_buffer_next].frame.seq_nr);
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ieee802154_frame_print_fcf_frame(&cc2420_rx_buffer[rx_buffer_next].frame);
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}
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#endif
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/* shift to next buffer element */
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if (++rx_buffer_next == CC2420_RX_BUF_SIZE) {
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rx_buffer_next = 0;
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}
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}
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