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/*
* OsmocomBB <-> SDR connection bridge
* TDMA scheduler: handlers for DL / UL bursts on logical channels
*
* (C) 2017 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/protocol/gsm_04_08.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmocom/coding/gsm0503_coding.h>
#include <osmocom/codec/codec.h>
#include "l1ctl_proto.h"
#include "scheduler.h"
#include "sched_trx.h"
#include "logging.h"
#include "trx_if.h"
#include "trxcon.h"
#include "l1ctl.h"
int rx_tchf_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;
int n_errors = -1, n_bits_total, rc;
sbit_t *buffer, *offset;
uint8_t l2[128], *mask;
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, "Traffic 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 = 0x00;
}
/* Update mask */
*mask |= (1 << bid);
/* Update mask and RSSI */
lchan->meas.rssi_sum += rssi;
lchan->meas.toa256_sum += toa256;
lchan->meas.rssi_num++;
lchan->meas.toa256_num++;
/* Copy burst to end of buffer of 8 bursts */
offset = buffer + bid * 116 + 464;
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 traffic frame at "
"fn=%u (%u/%u) for %s\n", *first_fn,
(*first_fn) % ts->mf_layout->period,
ts->mf_layout->period,
lchan_desc->name);
/* Send BFI */
goto bfi;
}
switch (lchan->tch_mode) {
case GSM48_CMODE_SIGN:
case GSM48_CMODE_SPEECH_V1: /* FR */
rc = gsm0503_tch_fr_decode(l2, buffer,
1, 0, &n_errors, &n_bits_total);
break;
case GSM48_CMODE_SPEECH_EFR: /* EFR */
rc = gsm0503_tch_fr_decode(l2, buffer,
1, 1, &n_errors, &n_bits_total);
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
/**
* TODO: AMR requires a dedicated loop,
* which will be implemented later...
*/
LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet\n");
return -ENOTSUP;
default:
LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode);
return -EINVAL;
}
/* Shift buffer by 4 bursts for interleaving */
memcpy(buffer, buffer + 464, 464);
/* Check decoding result */
if (rc < 4) {
LOGP(DSCHD, LOGL_ERROR, "Received bad TCH frame ending at "
"fn=%u for %s\n", fn, lchan_desc->name);
/* Send BFI */
goto bfi;
} else if (rc == GSM_MACBLOCK_LEN) {
/* FACCH received, forward it to the higher layers */
sched_send_dt_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN,
n_errors, false, false);
/* Send BFI instead of stolen TCH frame */
goto bfi;
} else {
/* A good TCH frame received */
l2_len = rc;
}
/* Send a traffic frame to the higher layers */
return sched_send_dt_ind(trx, ts, lchan, l2, l2_len,
n_errors, false, true);
bfi:
/* Bad frame indication */
l2_len = sched_bad_frame_ind(l2, lchan);
/* Didn't try to decode */
if (n_errors < 0)
n_errors = 116 * 4;
/* Send a BFI frame to the higher layers */
return sched_send_dt_ind(trx, ts, lchan, l2, l2_len,
n_errors, true, true);
}
int tx_tchf_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;
size_t l2_len;
int rc;
/* Set up pointers */
lchan_desc = &trx_lchan_desc[lchan->type];
mask = &lchan->tx_burst_mask;
buffer = lchan->tx_bursts;
/* If we have encoded bursts */
if (*mask)
goto send_burst;
/* Wait until a first burst in period */
if (bid > 0)
return 0;
/* Check the current TCH mode */
switch (lchan->tch_mode) {
case GSM48_CMODE_SIGN:
case GSM48_CMODE_SPEECH_V1: /* FR */
l2_len = GSM_FR_BYTES;
break;
case GSM48_CMODE_SPEECH_EFR: /* EFR */
l2_len = GSM_EFR_BYTES;
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
/**
* TODO: AMR requires a dedicated loop,
* which will be implemented later...
*/
LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet, "
"dropping frame...\n");
/* Forget this primitive */
sched_prim_drop(lchan);
return -ENOTSUP;
default:
LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u, "
"dropping frame...\n", lchan->tch_mode);
/* Forget this primitive */
sched_prim_drop(lchan);
return -EINVAL;
}
/* Determine and check the payload length */
if (lchan->prim->payload_len == GSM_MACBLOCK_LEN) {
l2_len = GSM_MACBLOCK_LEN; /* FACCH */
} else if (lchan->prim->payload_len != l2_len) {
LOGP(DSCHD, LOGL_ERROR, "Primitive has odd length %zu "
"(expected %zu for TCH or %u for FACCH), so dropping...\n",
lchan->prim->payload_len, l2_len, GSM_MACBLOCK_LEN);
sched_prim_drop(lchan);
return -EINVAL;
}
/* Shift buffer by 4 bursts back for interleaving */
memcpy(buffer, buffer + 464, 464);
/* Encode payload */
rc = gsm0503_tch_fr_encode(buffer, lchan->prim->payload, l2_len, 1);
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) {
/* Confirm data / traffic sending */
sched_send_dt_conf(trx, ts, lchan, fn, PRIM_IS_TCH(lchan->prim));
/* Forget processed primitive */
sched_prim_drop(lchan);
/* Reset mask */
*mask = 0x00;
}
return 0;
}
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