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/*
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <errno.h>
#include <string.h>
#include <stdint.h>
#include <osmocom/core/logging.h>
#include <osmocom/core/bits.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
#include <osmocom/coding/gsm0503_coding.h>
#include "l1ctl_proto.h"
#include "scheduler.h"
#include "sched_trx.h"
#include "logging.h"
#include "trx_if.h"
#include "l1ctl.h"
int rx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid,
sbit_t *bits, int8_t rssi, int16_t toa256)
{
const struct trx_lchan_desc *lchan_desc;
uint8_t l2[GPRS_L2_MAX_LEN], *mask;
int n_errors, n_bits_total, rc;
sbit_t *buffer, *offset;
uint32_t *first_fn;
size_t l2_len;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
first_fn = &lchan->rx_first_fn;
mask = &lchan->rx_burst_mask;
buffer = lchan->rx_bursts;
LOGP(DSCHD, LOGL_DEBUG, "Packet data received on %s: "
"fn=%u ts=%u bid=%u\n", lchan_desc->name, fn, ts->index, bid);
/* Reset internal state */
if (bid == 0) {
/* Clean up old measurements */
memset(&lchan->meas, 0x00, sizeof(lchan->meas));
*first_fn = fn;
*mask = 0x0;
}
/* Update mask */
*mask |= (1 << bid);
/* Update measurements */
lchan->meas.toa256_sum += toa256;
lchan->meas.rssi_sum += rssi;
lchan->meas.toa256_num++;
lchan->meas.rssi_num++;
/* Copy burst to buffer of 4 bursts */
offset = buffer + bid * 116;
memcpy(offset, bits + 3, 58);
memcpy(offset + 58, bits + 87, 58);
/* Wait until complete set of bursts */
if (bid != 3)
return 0;
/* Check for complete set of bursts */
if ((*mask & 0xf) != 0xf) {
LOGP(DSCHD, LOGL_ERROR, "Received incomplete data frame at "
"fn=%u (%u/%u) for %s\n", *first_fn,
(*first_fn) % ts->mf_layout->period,
ts->mf_layout->period,
lchan_desc->name);
return -1;
}
/* Attempt to decode */
rc = gsm0503_pdtch_decode(l2, buffer,
NULL, &n_errors, &n_bits_total);
if (rc < 0) {
LOGP(DSCHD, LOGL_ERROR, "Received bad packet data frame "
"at fn=%u (%u/%u) for %s\n", *first_fn,
(*first_fn) % ts->mf_layout->period,
ts->mf_layout->period,
lchan_desc->name);
}
/* Determine L2 length */
l2_len = rc > 0 ? rc : 0;
/* Send a L2 frame to the higher layers */
sched_send_dt_ind(trx, ts, lchan,
l2, l2_len, n_errors, rc < 0, true);
return 0;
}
int tx_pdtch_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid)
{
const struct trx_lchan_desc *lchan_desc;
ubit_t burst[GSM_BURST_LEN];
ubit_t *buffer, *offset;
const uint8_t *tsc;
uint8_t *mask;
int rc;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
mask = &lchan->tx_burst_mask;
buffer = lchan->tx_bursts;
if (bid > 0) {
/* If we have encoded bursts */
if (*mask)
goto send_burst;
else
return 0;
}
/* Encode payload */
rc = gsm0503_pdtch_encode(buffer, lchan->prim->payload,
lchan->prim->payload_len);
if (rc) {
LOGP(DSCHD, LOGL_ERROR, "Failed to encode L2 payload\n");
/* Forget this primitive */
sched_prim_drop(lchan);
return -EINVAL;
}
send_burst:
/* Determine which burst should be sent */
offset = buffer + bid * 116;
/* Update mask */
*mask |= (1 << bid);
/* Choose proper TSC */
tsc = sched_nb_training_bits[trx->tsc];
/* Compose a new burst */
memset(burst, 0, 3); /* TB */
memcpy(burst + 3, offset, 58); /* Payload 1/2 */
memcpy(burst + 61, tsc, 26); /* TSC */
memcpy(burst + 87, offset + 58, 58); /* Payload 2/2 */
memset(burst + 145, 0, 3); /* TB */
LOGP(DSCHD, LOGL_DEBUG, "Transmitting %s fn=%u ts=%u burst=%u\n",
lchan_desc->name, fn, ts->index, bid);
/* Forward burst to scheduler */
rc = sched_trx_handle_tx_burst(trx, ts, lchan, fn, burst);
if (rc) {
/* Forget this primitive */
sched_prim_drop(lchan);
/* Reset mask */
*mask = 0x00;
return rc;
}
/* If we have sent the last (4/4) burst */
if ((*mask & 0x0f) == 0x0f) {
/* Confirm data / traffic sending */
sched_send_dt_conf(trx, ts, lchan, fn, true);
/* Forget processed primitive */
sched_prim_drop(lchan);
/* Reset mask */
*mask = 0x00;
}
return 0;
}
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