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osmo-bts/src/osmo-bts-trx/sched_lchan_tchf.c

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/*
* (C) 2013 by Andreas Eversberg <jolly@eversberg.eu>
* (C) 2015-2017 by Harald Welte <laforge@gnumonks.org>
* Contributions by sysmocom - s.f.m.c. GmbH
*
* 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/msgb.h>
#include <osmocom/core/utils.h>
#include <osmocom/gsm/gsm0502.h>
#include <osmocom/codec/codec.h>
#include <osmocom/codec/ecu.h>
#include <osmocom/coding/gsm0503_coding.h>
#include <osmocom/coding/gsm0503_amr_dtx.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 <osmo-bts/msg_utils.h>
#include <sched_utils.h>
#include <amr_loop.h>
/* 3GPP TS 45.009, table 3.2.1.3-{1,3}: AMR on Uplink TCH/F.
*
* +---+---+---+---+---+---+---+---+
* | a | b | c | d | e | f | g | h | Burst 'a' received first
* +---+---+---+---+---+---+---+---+
* ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Speech/FACCH frame (bursts 'a' .. 'h')
*
* TDMA frame number of burst 'h' is always used as the table index. */
static const uint8_t sched_tchf_ul_amr_cmi_map[26] = {
[7] = 1, /* TCH/F: a=0 / h=7 */
[16] = 1, /* TCH/F: a=8 / h=16 */
[24] = 1, /* TCH/F: a=17 / h=24 */
};
/*! \brief a single TCH/F burst was received by the PHY, process it */
int rx_tchf_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
{
struct l1sched_chan_state *chan_state = &l1ts->chan_state[bi->chan];
struct gsm_lchan *lchan = chan_state->lchan;
sbit_t *burst, **bursts_p = &chan_state->ul_bursts;
uint8_t *mask = &chan_state->ul_mask;
uint8_t rsl_cmode = chan_state->rsl_cmode;
uint8_t tch_mode = chan_state->tch_mode;
uint8_t tch_data[128]; /* just to be safe */
enum sched_meas_avg_mode meas_avg_mode = SCHED_MEAS_AVG_M_S8N8;
struct l1sched_meas_set meas_avg;
int rc, amr = 0;
int n_errors = 0;
int n_bits_total = 0;
bool bfi_flag = false;
unsigned int fn_begin;
uint16_t ber10k;
uint8_t is_sub = 0;
uint8_t ft;
bool amr_is_cmr;
/* If handover RACH detection is turned on, treat this burst as an Access Burst.
* Handle NOPE.ind as usually to ensure proper Uplink measurement reporting. */
if (chan_state->ho_rach_detect == 1 && ~bi->flags & TRX_BI_F_NOPE_IND)
return rx_rach_fn(l1ts, bi);
LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi, "Received TCH/F, bid=%u\n", bi->bid);
/* allocate burst memory, if not already */
if (!*bursts_p) {
*bursts_p = talloc_zero_size(l1ts, 928);
if (!*bursts_p)
return -ENOMEM;
}
/* shift the buffer by 4 bursts leftwards */
if (bi->bid == 0) {
memcpy(*bursts_p, *bursts_p + 464, 464);
memset(*bursts_p + 464, 0, 464);
*mask = *mask << 4;
}
/* update mask */
*mask |= (1 << bi->bid);
/* store measurements */
trx_sched_meas_push(chan_state, bi);
/* copy burst to end of buffer of 8 bursts */
burst = *bursts_p + bi->bid * 116 + 464;
if (bi->burst_len > 0) {
memcpy(burst, bi->burst + 3, 58);
memcpy(burst + 58, bi->burst + 87, 58);
} else
memset(burst, 0, 116);
/* wait until complete set of bursts */
if (bi->bid != 3)
return 0;
/* fill up the burst buffer so that we have 8 bursts in there */
if (OSMO_UNLIKELY((*mask & 0xff) != 0xff)) {
LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi,
"UL burst buffer is not filled up: mask=0x%02x != 0xff\n",
*mask);
return 0; /* TODO: send BFI */
}
/* decode
* also shift buffer by 4 bursts for interleaving */
switch (tch_mode) {
case GSM48_CMODE_SIGN:
case GSM48_CMODE_SPEECH_V1: /* FR */
rc = gsm0503_tch_fr_decode(tch_data, *bursts_p, 1, 0, &n_errors, &n_bits_total);
if (rc == GSM_FR_BYTES) /* only for valid *speech* frames */
lchan_set_marker(osmo_fr_check_sid(tch_data, rc), lchan); /* DTXu */
break;
case GSM48_CMODE_SPEECH_EFR: /* EFR */
rc = gsm0503_tch_fr_decode(tch_data, *bursts_p, 1, 1, &n_errors, &n_bits_total);
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
/* the first FN 0,8,17 defines that CMI is included in frame,
* the first FN 4,13,21 defines that CMR is included in frame.
* NOTE: A frame ends 7 FN after start.
*/
amr_is_cmr = !sched_tchf_ul_amr_cmi_map[bi->fn % 26];
/* The AFS_ONSET frame itself does not result into an RTP frame
* since it only contains a recognition pattern that marks the
* end of the DTX interval. To mark the end of the DTX interval
* in the RTP stream as well, the voice frame after the
* AFS_ONSET frame is used. */
if (chan_state->amr_last_dtx == AFS_ONSET)
lchan_set_marker(false, lchan);
/* we store tch_data + 2 header bytes, the amr variable set to
* 2 will allow us to skip the first 2 bytes in case we did
* receive an FACCH frame instead of a voice frame (we do not
* know this before we actually decode the frame) */
amr = 2;
rc = gsm0503_tch_afs_decode_dtx(tch_data + amr, *bursts_p,
amr_is_cmr, chan_state->codec, chan_state->codecs, &chan_state->ul_ft,
&chan_state->ul_cmr, &n_errors, &n_bits_total, &chan_state->amr_last_dtx);
/* Tag all frames that are not regular AMR voice frames as
* SUB-Frames */
if (chan_state->amr_last_dtx != AMR_OTHER) {
LOGL1SB(DL1P, LOGL_DEBUG, l1ts, bi,
"Received AMR DTX frame (rc=%d, BER %d/%d): %s\n",
rc, n_errors, n_bits_total,
gsm0503_amr_dtx_frame_name(chan_state->amr_last_dtx));
is_sub = 1;
}
/* The occurrence of the following frames indicates that we
* are either at the beginning or in the middle of a talk
* spurt. We update the SID status accordingly, but we do
* not want the marker to be set, since this must only
* happen when the talk spurt is over (see above) */
switch (chan_state->amr_last_dtx) {
case AFS_SID_FIRST:
case AFS_SID_UPDATE:
case AFS_SID_UPDATE_CN:
lchan_set_marker(true, lchan);
lchan->rtp_tx_marker = false;
break;
}
switch (chan_state->amr_last_dtx) {
case AFS_SID_FIRST:
case AFS_SID_UPDATE_CN:
meas_avg_mode = SCHED_MEAS_AVG_M_S8N4;
break;
case AFS_SID_UPDATE:
case AFS_ONSET:
meas_avg_mode = SCHED_MEAS_AVG_M_S4N4;
break;
}
/* only good speech frames get rtp header */
if (rc != GSM_MACBLOCK_LEN && rc >= 4) {
if (chan_state->amr_last_dtx == AMR_OTHER) {
ft = chan_state->codec[chan_state->ul_ft];
} else {
/* SID frames will always get Frame Type Index 8 (AMR_SID) */
ft = AMR_SID;
}
rc = osmo_amr_rtp_enc(tch_data,
chan_state->codec[chan_state->ul_cmr],
ft, AMR_GOOD);
}
break;
default:
LOGL1SB(DL1P, LOGL_ERROR, l1ts, bi,
"TCH mode %u invalid, please fix!\n",
tch_mode);
return -EINVAL;
}
/* average measurements of the last N (depends on mode) bursts */
trx_sched_meas_avg(chan_state, &meas_avg, meas_avg_mode);
/* meas_avg.fn now contains TDMA frame number of the first burst */
fn_begin = meas_avg.fn;
if (tch_mode == GSM48_CMODE_SPEECH_AMR)
trx_loop_amr_input(chan_state, &meas_avg);
/* Check if the frame is bad */
if (rc < 0) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, bi, "Received bad data (%u/%u)\n",
bi->fn % l1ts->mf_period, l1ts->mf_period);
bfi_flag = true;
} else if (rc < 4) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, bi,
"Received bad data (%u/%u) with invalid codec mode %d\n",
bi->fn % l1ts->mf_period, l1ts->mf_period, rc);
bfi_flag = true;
}
if (rc != GSM_MACBLOCK_LEN && lchan->ecu_state)
osmo_ecu_frame_in(lchan->ecu_state, bfi_flag, tch_data, rc);
ber10k = compute_ber10k(n_bits_total, n_errors);
if (bfi_flag)
goto bfi;
/* FACCH */
if (rc == GSM_MACBLOCK_LEN) {
_sched_compose_ph_data_ind(l1ts, fn_begin, bi->chan,
tch_data + amr, GSM_MACBLOCK_LEN,
meas_avg.rssi, meas_avg.toa256,
meas_avg.ci_cb, ber10k,
PRES_INFO_UNKNOWN);
/* If we are in SPEECH mode we will generate a fake (BFI) TCH
* indication as well. This indication is needed by the higher
* layers, however we already have reported the measurement
* result for the current block together with the FACCH.
* To avoid reporting the same measurement result again with
* the fake (BFI) TCH indication we set meas_avg.rssi to zero.
* Doing so tells l1sap.c to ignore the measurement result. */
meas_avg.rssi = 0;
bfi:
if (rsl_cmode == RSL_CMOD_SPD_SPEECH) {
/* indicate bad frame */
if (lchan->tch.dtx.ul_sid) {
/* DTXu: pause in progress. Push empty payload to upper layers */
rc = 0;
goto compose_l1sap;
}
/* If there is an ECU active on this channel, use its output */
if (lchan->ecu_state) {
rc = osmo_ecu_frame_out(lchan->ecu_state, tch_data);
if (rc >= 0) /* Otherwise we send a BFI */
goto compose_l1sap;
}
switch (tch_mode) {
case GSM48_CMODE_SPEECH_V1: /* FR */
memset(tch_data, 0, GSM_FR_BYTES);
tch_data[0] = 0xd0;
rc = GSM_FR_BYTES;
break;
case GSM48_CMODE_SPEECH_EFR: /* EFR */
memset(tch_data, 0, GSM_EFR_BYTES);
tch_data[0] = 0xc0;
rc = GSM_EFR_BYTES;
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
rc = osmo_amr_rtp_enc(tch_data,
chan_state->codec[chan_state->ul_cmr],
chan_state->codec[chan_state->ul_ft],
AMR_BAD);
if (rc < 2) {
LOGL1SB(DL1P, LOGL_ERROR, l1ts, bi,
"Failed to encode AMR_BAD frame (rc=%d), "
"not sending BFI\n", rc);
return -EINVAL;
}
memset(tch_data + 2, 0, rc - 2);
break;
default:
LOGL1SB(DL1P, LOGL_ERROR, l1ts, bi,
"TCH mode %u invalid, please fix!\n", tch_mode);
return -EINVAL;
}
}
}
if (rsl_cmode != RSL_CMOD_SPD_SPEECH)
return 0;
/* TCH or BFI */
compose_l1sap:
return _sched_compose_tch_ind(l1ts, fn_begin, bi->chan, tch_data, rc,
meas_avg.toa256, ber10k, meas_avg.rssi,
meas_avg.ci_cb, is_sub);
}
/* common section for generation of TCH bursts (TCH/H and TCH/F).
* FIXME: this function is over-complicated, refactor / get rid of it. */
struct msgb *tch_dl_dequeue(struct l1sched_ts *l1ts, struct trx_dl_burst_req *br)
{
struct msgb *msg1, *msg2, *msg_tch = NULL, *msg_facch = NULL;
struct l1sched_chan_state *chan_state = &l1ts->chan_state[br->chan];
uint8_t rsl_cmode = chan_state->rsl_cmode;
uint8_t tch_mode = chan_state->tch_mode;
struct osmo_phsap_prim *l1sap;
/* get frame and unlink from queue */
msg1 = _sched_dequeue_prim(l1ts, br);
msg2 = _sched_dequeue_prim(l1ts, br);
if (msg1) {
l1sap = msgb_l1sap_prim(msg1);
if (l1sap->oph.primitive == PRIM_TCH) {
msg_tch = msg1;
if (msg2) {
l1sap = msgb_l1sap_prim(msg2);
if (l1sap->oph.primitive == PRIM_TCH) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br, "TCH twice, please FIX!\n");
msgb_free(msg2);
} else
msg_facch = msg2;
}
} else {
msg_facch = msg1;
if (msg2) {
l1sap = msgb_l1sap_prim(msg2);
if (l1sap->oph.primitive != PRIM_TCH) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br, "FACCH twice, please FIX!\n");
msgb_free(msg2);
} else
msg_tch = msg2;
}
}
}
/* check validity of message */
if (msg_facch && msgb_l2len(msg_facch) != GSM_MACBLOCK_LEN) {
LOGL1SB(DL1P, LOGL_FATAL, l1ts, br, "Prim has odd len=%u != %u\n",
msgb_l2len(msg_facch), GSM_MACBLOCK_LEN);
/* free message */
msgb_free(msg_facch);
msg_facch = NULL;
}
/* prioritize FACCH over speech */
if (msg_facch) {
/* Unlike SACCH, FACCH has no dedicated slots on the multiframe layout.
* It's multiplexed together with TCH (speech or data) frames basically
* by replacing (stealing) them. This is common for both TCH/F and
* TCH/H, with the only difference that FACCH/H steals two TCH frames
* (not just one) due to a longer interleaving period. */
msgb_free(msg_tch);
return msg_facch;
}
/* check validity of message, get AMR ft and cmr */
if (msg_tch) {
int len;
uint8_t cmr_codec;
int ft, i;
enum osmo_amr_type ft_codec;
enum osmo_amr_quality bfi;
int8_t sti, cmi;
bool amr_is_cmr = !dl_amr_fn_is_cmi(br->fn);
if (rsl_cmode != RSL_CMOD_SPD_SPEECH) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, br, "Dropping speech frame, "
"because we are not in speech mode\n");
goto free_bad_msg;
}
switch (tch_mode) {
case GSM48_CMODE_SPEECH_V1: /* FR / HR */
if (br->chan != TRXC_TCHF) /* HR */
len = 15;
else
len = GSM_FR_BYTES;
break;
case GSM48_CMODE_SPEECH_EFR: /* EFR */
if (br->chan != TRXC_TCHF)
goto inval_mode2;
len = GSM_EFR_BYTES;
break;
case GSM48_CMODE_SPEECH_AMR: /* AMR */
len = osmo_amr_rtp_dec(msg_tch->l2h, msgb_l2len(msg_tch),
&cmr_codec, &cmi, &ft_codec,
&bfi, &sti);
if (len < 0) {
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br, "Cannot send invalid AMR payload\n");
goto free_bad_msg;
}
ft = -1;
for (i = 0; i < chan_state->codecs; i++) {
if (chan_state->codec[i] == ft_codec)
ft = i;
}
if (ft < 0) {
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br,
"Codec (FT = %d) of RTP frame not in list\n", ft_codec);
goto free_bad_msg;
}
if (amr_is_cmr && chan_state->dl_ft != ft) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, br, "Codec (FT = %d) "
" of RTP cannot be changed now, but in next frame\n", ft_codec);
goto free_bad_msg;
}
chan_state->dl_ft = ft;
if (bfi == AMR_BAD) {
LOGL1SB(DL1P, LOGL_NOTICE, l1ts, br, "Transmitting 'bad AMR frame'\n");
goto free_bad_msg;
}
break;
default:
inval_mode2:
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br, "TCH mode invalid, please fix!\n");
goto free_bad_msg;
}
if (msgb_l2len(msg_tch) != len) {
LOGL1SB(DL1P, LOGL_ERROR, l1ts, br, "Cannot send payload with "
"invalid length! (expecting %d, received %d)\n",
len, msgb_l2len(msg_tch));
free_bad_msg:
/* free message */
msgb_free(msg_tch);
msg_tch = NULL;
}
}
return msg_tch;
}
/* obtain a to-be-transmitted TCH/F (Full Traffic Channel) burst */
int tx_tchf_fn(struct l1sched_ts *l1ts, struct trx_dl_burst_req *br)
{
struct l1sched_chan_state *chan_state = &l1ts->chan_state[br->chan];
uint8_t tch_mode = chan_state->tch_mode;
ubit_t *burst, **bursts_p = &chan_state->dl_bursts;
struct msgb *msg;
/* send burst, if we already got a frame */
if (br->bid > 0) {
if (!*bursts_p)
return -ENODEV;
goto send_burst;
}
/* BURST BYPASS */
/* allocate burst memory, if not already,
* otherwise shift buffer by 4 bursts for interleaving */
if (!*bursts_p) {
*bursts_p = talloc_zero_size(l1ts, 928);
if (!*bursts_p)
return -ENOMEM;
} else {
memcpy(*bursts_p, *bursts_p + 464, 464);
memset(*bursts_p + 464, 0, 464);
}
/* dequeue a message to be transmitted */
msg = tch_dl_dequeue(l1ts, br);
/* no message at all, send a dummy L2 frame on FACCH */
if (msg == NULL) {
static const uint8_t dummy[GSM_MACBLOCK_LEN] = {
0x03, 0x03, 0x01, /* TODO: use randomized padding */
0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b, 0x2b,
};
LOGL1SB(DL1P, LOGL_DEBUG, l1ts, br, "No TCH or FACCH prim for transmit.\n");
gsm0503_tch_fr_encode(*bursts_p, dummy, sizeof(dummy), 1);
chan_state->dl_facch_bursts = 8;
goto send_burst;
}
/* populate the buffer with bursts */
if (msgb_l2len(msg) == GSM_MACBLOCK_LEN) {
gsm0503_tch_fr_encode(*bursts_p, msg->l2h, msgb_l2len(msg), 1);
chan_state->dl_facch_bursts = 8;
} else if (tch_mode == GSM48_CMODE_SPEECH_AMR)
/* the first FN 4,13,21 defines that CMI is included in frame,
* the first FN 0,8,17 defines that CMR is included in frame.
*/
gsm0503_tch_afs_encode(*bursts_p, msg->l2h + 2,
msgb_l2len(msg) - 2, !dl_amr_fn_is_cmi(br->fn),
chan_state->codec, chan_state->codecs,
chan_state->dl_ft,
chan_state->dl_cmr);
else
gsm0503_tch_fr_encode(*bursts_p, msg->l2h, msgb_l2len(msg), 1);
/* free message */
msgb_free(msg);
send_burst:
/* compose burst */
burst = *bursts_p + br->bid * 116;
memcpy(br->burst + 3, burst, 58);
memcpy(br->burst + 61, TRX_GMSK_NB_TSC(br), 26);
memcpy(br->burst + 87, burst + 58, 58);
br->burst_len = GSM_BURST_LEN;
if (chan_state->dl_facch_bursts > 0) {
chan_state->dl_facch_bursts--;
br->flags |= TRX_BR_F_FACCH;
}
LOGL1SB(DL1P, LOGL_DEBUG, l1ts, br, "Transmitting burst=%u.\n", br->bid);
return 0;
}
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