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/*
* (C) 2013 by Andreas Eversberg <jolly@eversberg.eu>
* (C) 2015-2017 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 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 Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#include <stdint.h>
#include <errno.h>
#include <osmocom/core/bits.h>
#include <osmocom/core/utils.h>
#include <osmocom/coding/gsm0503_coding.h>
#include <osmo-bts/bts.h>
#include <osmo-bts/l1sap.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/scheduler.h>
#include <osmo-bts/scheduler_backend.h>
#include <sched_utils.h>
/* Maximum size of a EGPRS message in bytes */
#define EGPRS_0503_MAX_BYTES 155
/*! \brief a single PDTCH burst was received by the PHY, process it */
int rx_pdtch_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
uint8_t bid, const struct trx_ul_burst_ind *bi)
{
struct l1sched_ts *l1ts = l1sched_trx_get_ts(l1t, bi->tn);
struct l1sched_chan_state *chan_state = &l1ts->chan_state[chan];
sbit_t *burst, **bursts_p = &chan_state->ul_bursts;
uint32_t *first_fn = &chan_state->ul_first_fn;
uint8_t *mask = &chan_state->ul_mask;
float *rssi_sum = &chan_state->rssi_sum;
uint8_t *rssi_num = &chan_state->rssi_num;
int32_t *toa256_sum = &chan_state->toa256_sum;
uint8_t *toa_num = &chan_state->toa_num;
int32_t *ci_cb_sum = &chan_state->ci_cb_sum;
uint8_t *ci_cb_num = &chan_state->ci_cb_num;
uint8_t l2[EGPRS_0503_MAX_BYTES];
int n_errors = 0;
int n_bursts_bits = 0;
int n_bits_total = 0;
int16_t lqual_cb;
uint16_t ber10k;
int rc;
LOGL1S(DL1P, LOGL_DEBUG, l1t, bi->tn, chan, bi->fn,
"Received PDTCH bid=%u\n", bid);
/* allocate burst memory, if not already */
if (!*bursts_p) {
*bursts_p = talloc_zero_size(tall_bts_ctx,
GSM0503_EGPRS_BURSTS_NBITS);
if (!*bursts_p)
return -ENOMEM;
}
/* clear burst */
if (bid == 0) {
memset(*bursts_p, 0, GSM0503_EGPRS_BURSTS_NBITS);
*mask = 0x0;
*first_fn = bi->fn;
*rssi_sum = 0;
*rssi_num = 0;
*toa256_sum = 0;
*toa_num = 0;
*ci_cb_sum = 0;
*ci_cb_num = 0;
}
/* update mask + rssi */
*mask |= (1 << bid);
*rssi_sum += bi->rssi;
(*rssi_num)++;
*toa256_sum += bi->toa256;
(*toa_num)++;
/* C/I: Carrier-to-Interference ratio (in centiBels) */
if (bi->flags & TRX_BI_F_CI_CB) {
*ci_cb_sum += bi->ci_cb;
(*ci_cb_num)++;
}
/* copy burst to buffer of 4 bursts */
if (bi->burst_len == EGPRS_BURST_LEN) {
burst = *bursts_p + bid * 348;
memcpy(burst, bi->burst + 9, 174);
memcpy(burst + 174, bi->burst + 261, 174);
n_bursts_bits = GSM0503_EGPRS_BURSTS_NBITS;
} else {
burst = *bursts_p + bid * 116;
memcpy(burst, bi->burst + 3, 58);
memcpy(burst + 58, bi->burst + 87, 58);
n_bursts_bits = GSM0503_GPRS_BURSTS_NBITS;
}
/* wait until complete set of bursts */
if (bid != 3)
return 0;
/* check for complete set of bursts */
if ((*mask & 0xf) != 0xf) {
LOGL1S(DL1P, LOGL_DEBUG, l1t, bi->tn, chan, bi->fn,
"Received incomplete frame (%u/%u)\n",
bi->fn % l1ts->mf_period, l1ts->mf_period);
}
*mask = 0x0;
/*
* Attempt to decode EGPRS bursts first. For 8-PSK EGPRS this is all we
* do. Attempt GPRS decoding on EGPRS failure. If the burst is GPRS,
* then we incur decoding overhead of 31 bits on the Type 3 EGPRS
* header, which is tolerable.
*/
rc = gsm0503_pdtch_egprs_decode(l2, *bursts_p, n_bursts_bits,
NULL, &n_errors, &n_bits_total);
if ((bi->burst_len == GSM_BURST_LEN) && (rc < 0)) {
rc = gsm0503_pdtch_decode(l2, *bursts_p, NULL,
&n_errors, &n_bits_total);
}
if (rc <= 0) {
LOGL1S(DL1P, LOGL_DEBUG, l1t, bi->tn, chan, bi->fn,
"Received bad PDTCH (%u/%u)\n",
bi->fn % l1ts->mf_period, l1ts->mf_period);
return 0;
}
lqual_cb = *ci_cb_num ? (*ci_cb_sum / *ci_cb_num) : 0;
ber10k = compute_ber10k(n_bits_total, n_errors);
return _sched_compose_ph_data_ind(l1t, bi->tn,
*first_fn, chan, l2, rc,
*rssi_sum / *rssi_num,
*toa256_sum / *toa_num,
lqual_cb, ber10k,
PRES_INFO_BOTH);
}
/* obtain a to-be-transmitted PDTCH (packet data) burst */
int tx_pdtch_fn(struct l1sched_trx *l1t, enum trx_chan_type chan,
uint8_t bid, struct trx_dl_burst_req *br)
{
struct l1sched_ts *l1ts = l1sched_trx_get_ts(l1t, br->tn);
struct gsm_bts_trx_ts *ts = &l1t->trx->ts[br->tn];
struct msgb *msg = NULL; /* make GCC happy */
ubit_t *burst, **bursts_p = &l1ts->chan_state[chan].dl_bursts;
enum trx_burst_type *burst_type = &l1ts->chan_state[chan].dl_burst_type;
int rc = 0;
/* send burst, if we already got a frame */
if (bid > 0) {
if (!*bursts_p)
return 0;
goto send_burst;
}
/* get mac block from queue */
msg = _sched_dequeue_prim(l1t, br->tn, br->fn, chan);
if (msg)
goto got_msg;
LOGL1S(DL1P, LOGL_INFO, l1t, br->tn, chan, br->fn, "No prim for transmit.\n");
no_msg:
/* free burst memory */
if (*bursts_p) {
talloc_free(*bursts_p);
*bursts_p = NULL;
}
return -ENODEV;
got_msg:
/* BURST BYPASS */
/* allocate burst memory, if not already */
if (!*bursts_p) {
*bursts_p = talloc_zero_size(tall_bts_ctx,
GSM0503_EGPRS_BURSTS_NBITS);
if (!*bursts_p)
return -ENOMEM;
}
/* encode bursts */
rc = gsm0503_pdtch_egprs_encode(*bursts_p, msg->l2h, msg->tail - msg->l2h);
if (rc < 0)
rc = gsm0503_pdtch_encode(*bursts_p, msg->l2h, msg->tail - msg->l2h);
/* check validity of message */
if (rc < 0) {
LOGL1S(DL1P, LOGL_FATAL, l1t, br->tn, chan, br->fn, "Prim invalid length, please FIX! "
"(len=%ld)\n", (long)(msg->tail - msg->l2h));
/* free message */
msgb_free(msg);
goto no_msg;
} else if (rc == GSM0503_EGPRS_BURSTS_NBITS) {
*burst_type = TRX_BURST_8PSK;
} else {
*burst_type = TRX_BURST_GMSK;
}
/* free message */
msgb_free(msg);
send_burst:
/* compose burst */
if (*burst_type == TRX_BURST_8PSK) {
burst = *bursts_p + bid * 348;
memset(br->burst, 1, 9);
memcpy(br->burst + 9, burst, 174);
memcpy(br->burst + 183, _sched_egprs_tsc[gsm_ts_tsc(ts)], 78);
memcpy(br->burst + 261, burst + 174, 174);
memset(br->burst + 435, 1, 9);
br->burst_len = EGPRS_BURST_LEN;
} else {
burst = *bursts_p + bid * 116;
memcpy(br->burst + 3, burst, 58);
memcpy(br->burst + 61, _sched_tsc[gsm_ts_tsc(ts)], 26);
memcpy(br->burst + 87, burst + 58, 58);
br->burst_len = GSM_BURST_LEN;
}
LOGL1S(DL1P, LOGL_DEBUG, l1t, br->tn, chan, br->fn, "Transmitting burst=%u.\n", bid);
return 0;
}
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