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Harald Welte gerrit-no-reply at lists.osmocom.org
Review at https://gerrit.osmocom.org/6803
host/trxcon/scheduler: add initial TCH/F channel support
This change implements basic TCH/F lchan handlers for both data
reception and transmission. Only FACCH (signaling), FR and EFR
payloads are supported at the moment.
Change-Id: If6b0eaede2b484484d2a824e7219ff04483266a1
---
M src/host/trxcon/Makefile.am
M src/host/trxcon/sched_lchan_common.c
M src/host/trxcon/sched_lchan_desc.c
A src/host/trxcon/sched_lchan_tchf.c
M src/host/trxcon/sched_trx.h
5 files changed, 386 insertions(+), 2 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/osmocom-bb refs/changes/03/6803/1
diff --git a/src/host/trxcon/Makefile.am b/src/host/trxcon/Makefile.am
index 90c7a3c..88ff2be 100644
--- a/src/host/trxcon/Makefile.am
+++ b/src/host/trxcon/Makefile.am
@@ -34,6 +34,7 @@
sched_lchan_common.c \
sched_lchan_desc.c \
sched_lchan_xcch.c \
+ sched_lchan_tchf.c \
sched_lchan_rach.c \
sched_lchan_sch.c \
sched_mframe.c \
diff --git a/src/host/trxcon/sched_lchan_common.c b/src/host/trxcon/sched_lchan_common.c
index 925a441..6d75533 100644
--- a/src/host/trxcon/sched_lchan_common.c
+++ b/src/host/trxcon/sched_lchan_common.c
@@ -33,6 +33,7 @@
#include <osmocom/core/bits.h>
#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/protocol/gsm_08_58.h>
#include "l1ctl_proto.h"
#include "scheduler.h"
@@ -145,3 +146,82 @@
return 0;
}
+
+/**
+ * Composes a bad frame indication message
+ * according to the current tch_mode.
+ *
+ * @param l2 Pointer to allocated byte array
+ * @param tch_mode Current TCH mode
+ * @return How much bytes were written
+ */
+size_t sched_bad_frame_ind(uint8_t *l2, uint8_t rsl_cmode, uint8_t tch_mode)
+{
+ /* BFI is only required for speech */
+ if (rsl_cmode != RSL_CMOD_SPD_SPEECH)
+ return 0;
+
+ switch (tch_mode) {
+ case GSM48_CMODE_SIGN:
+ case GSM48_CMODE_SPEECH_V1: /* Full Rate */
+ memset(l2, 0x00, GSM_FR_BYTES);
+ l2[0] = 0xd0;
+ return GSM_FR_BYTES;
+ case GSM48_CMODE_SPEECH_EFR: /* Enhanced Full Rate */
+ memset(l2, 0x00, GSM_EFR_BYTES);
+ l2[0] = 0xc0;
+ return GSM_EFR_BYTES;
+ case GSM48_CMODE_SPEECH_AMR: /* Adaptive Multi Rate */
+ /* FIXME: AMR is not implemented yet */
+ return 0;
+ default:
+ LOGP(DSCH, LOGL_ERROR, "Invalid TCH mode: %u\n", tch_mode);
+ return 0;
+ }
+}
+
+#define PRIM_IS_FACCH(prim) \
+ prim->payload_len == GSM_MACBLOCK_LEN
+
+#define PRIM_IS_TCH(prim) \
+ prim->payload_len != GSM_MACBLOCK_LEN
+
+struct trx_ts_prim *sched_dequeue_tch_prim(struct llist_head *queue)
+{
+ struct trx_ts_prim *a, *b;
+
+ /* Obtain the first prim from TX queue */
+ a = llist_entry(queue->next, struct trx_ts_prim, list);
+
+ /* If this is the only one => do nothing... */
+ if (queue->next->next == queue)
+ return a;
+
+ /* Obtain the second prim from TX queue */
+ b = llist_entry(queue->next->next, struct trx_ts_prim, list);
+
+ /* Find and prioritize FACCH */
+ if (PRIM_IS_FACCH(a) && PRIM_IS_TCH(b)) {
+ /**
+ * Case 1: first is FACCH, second is TCH:
+ * Prioritize FACCH, dropping TCH
+ */
+ llist_del(&b->list);
+ talloc_free(b);
+ return a;
+ } else if (PRIM_IS_TCH(a) && PRIM_IS_FACCH(b)) {
+ /**
+ * Case 2: first is TCH, second is FACCH:
+ * Prioritize FACCH, dropping TCH
+ */
+ llist_del(&a->list);
+ talloc_free(a);
+ return b;
+ } else {
+ /**
+ * Otherwise: both are TCH or FACCH frames:
+ * Nothing to prioritize, return the first one
+ */
+ return a;
+ }
+}
diff --git a/src/host/trxcon/sched_lchan_desc.c b/src/host/trxcon/sched_lchan_desc.c
index c483db8..390b1ef 100644
--- a/src/host/trxcon/sched_lchan_desc.c
+++ b/src/host/trxcon/sched_lchan_desc.c
@@ -30,11 +30,9 @@
/* TODO: implement */
#define tx_pdtch_fn NULL
-#define tx_tchf_fn NULL
#define tx_tchh_fn NULL
#define rx_pdtch_fn NULL
-#define rx_tchf_fn NULL
#define rx_tchh_fn NULL
/* Forward declaration of handlers */
@@ -52,6 +50,13 @@
int tx_rach_fn(struct trx_instance *trx, struct trx_ts *ts,
struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid);
+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, float toa);
+
+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 trx_lchan_desc[_TRX_CHAN_MAX] = {
{
TRXC_IDLE, "IDLE",
diff --git a/src/host/trxcon/sched_lchan_tchf.c b/src/host/trxcon/sched_lchan_tchf.c
new file mode 100644
index 0000000..237e538
--- /dev/null
+++ b/src/host/trxcon/sched_lchan_tchf.c
@@ -0,0 +1,292 @@
+/*
+ * OsmocomBB <-> SDR connection bridge
+ * TDMA scheduler: handlers for DL / UL bursts on logical channels
+ *
+ * (C) 2017 by Vadim Yanitskiy <axilirator at 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 <talloc.h>
+#include <stdint.h>
+
+#include <osmocom/core/linuxlist.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/bits.h>
+
+#include <osmocom/gsm/protocol/gsm_04_08.h>
+#include <osmocom/gsm/protocol/gsm_08_58.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, float toa)
+{
+ const struct trx_lchan_desc *lchan_desc;
+ uint8_t rsl_cmode, tch_mode, mode;
+ int n_errors, 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.toa_sum += toa;
+ lchan->meas.rssi_num++;
+ lchan->meas.toa_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_DEBUG, "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);
+ return -EINVAL;
+ }
+
+ /**
+ * Get current RSL / TCH modes
+ *
+ * FIXME: we do support speech only, and
+ * CSD support may be implemented latter.
+ */
+ rsl_cmode = RSL_CMOD_SPD_SPEECH;
+ tch_mode = lchan->tch_mode;
+
+ mode = rsl_cmode != RSL_CMOD_SPD_SPEECH ?
+ GSM48_CMODE_SPEECH_V1 : tch_mode;
+
+ switch (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", 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_DEBUG, "Received bad TCH frame ending at "
+ "fn=%u for %s\n", fn, lchan_desc->name);
+
+ l2_len = sched_bad_frame_ind(l2, rsl_cmode, tch_mode);
+ } else if (rc == GSM_MACBLOCK_LEN) {
+ /* FACCH received, forward it to the higher layers */
+ sched_send_data_ind(trx, ts, lchan, l2, GSM_MACBLOCK_LEN);
+ /* Send BFI instead of stolen TCH frame */
+ l2_len = sched_bad_frame_ind(l2, rsl_cmode, tch_mode);
+ } else {
+ /* A good TCH frame received */
+ l2_len = rc;
+ }
+
+ /* Send a traffic frame to the higher layers */
+ if (l2_len > 0)
+ sched_send_data_ind(trx, ts, lchan, l2, l2_len);
+
+ return 0;
+}
+
+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;
+ struct trx_ts_prim *prim;
+ ubit_t burst[GSM_BURST_LEN];
+ ubit_t *buffer, *offset;
+ uint8_t *mask, *l2;
+ const uint8_t *tsc;
+ 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...
+ */
+ /* TODO: drop prim here */
+ LOGP(DSCHD, LOGL_ERROR, "AMR isn't supported yet\n");
+ return -ENOTSUP;
+ default:
+ /* TODO: drop prim here */
+ LOGP(DSCHD, LOGL_ERROR, "Invalid TCH mode: %u\n",
+ lchan->tch_mode);
+ return -EINVAL;
+ }
+
+ /* Get a message from TX queue */
+ prim = sched_dequeue_tch_prim(&ts->tx_prims);
+ l2 = (uint8_t *) prim->payload;
+
+ /* Determine payload length */
+ if (prim->payload_len == GSM_MACBLOCK_LEN)
+ l2_len = GSM_MACBLOCK_LEN;
+
+ /* Shift buffer by 4 bursts back for interleaving */
+ memcpy(buffer, buffer + 464, 464);
+
+ /* Encode payload */
+ rc = gsm0503_tch_fr_encode(buffer, l2, l2_len, 1);
+ if (rc) {
+ LOGP(DSCHD, LOGL_ERROR, "Failed to encode L2 payload\n");
+
+ /* Remove primitive from queue and free memory */
+ llist_del(&prim->list);
+ talloc_free(prim);
+
+ 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);
+
+ /* Send burst to transceiver */
+ rc = trx_if_tx_burst(trx, ts->index, fn, trx->tx_power, burst);
+ if (rc) {
+ LOGP(DSCHD, LOGL_ERROR, "Could not send burst to transceiver\n");
+
+ /* Remove primitive from queue and free memory */
+ prim = llist_entry(ts->tx_prims.next, struct trx_ts_prim, list);
+ llist_del(&prim->list);
+ talloc_free(prim);
+
+ /* Reset mask */
+ *mask = 0x00;
+
+ return rc;
+ }
+
+ /* If we have sent the last (4/4) burst */
+ if (*mask == 0x0f) {
+ /* Get pointer to a prim which was sent */
+ prim = llist_entry(ts->tx_prims.next, struct trx_ts_prim, list);
+
+ /* Confirm data / traffic sending */
+ sched_send_data_conf(trx, ts, lchan, fn, prim->payload_len);
+
+ /* Remove primitive from queue and free memory */
+ llist_del(&prim->list);
+ talloc_free(prim);
+
+ /* Reset mask */
+ *mask = 0x00;
+ }
+
+ return 0;
+}
diff --git a/src/host/trxcon/sched_trx.h b/src/host/trxcon/sched_trx.h
index de7e073..268c6b7 100644
--- a/src/host/trxcon/sched_trx.h
+++ b/src/host/trxcon/sched_trx.h
@@ -22,6 +22,11 @@
#define MAX_A5_KEY_LEN (128 / 8)
+/* TS 101318 Chapter 5.1: 260 bits + 4bit sig */
+#define GSM_FR_BYTES 33
+/* TS 101318 Chapter 5.3: 244 bits + 4bit sig */
+#define GSM_EFR_BYTES 31
+
/* Forward declaration to avoid mutual include */
struct trx_lchan_state;
struct trx_instance;
@@ -262,6 +267,7 @@
size_t pl_len, uint8_t chan_nr, uint8_t link_id);
int sched_trx_push_prim(struct trx_instance *trx,
struct trx_ts_prim *prim, uint8_t chan_nr);
+struct trx_ts_prim *sched_dequeue_tch_prim(struct llist_head *queue);
int sched_trx_handle_rx_burst(struct trx_instance *trx, uint8_t tn,
uint32_t burst_fn, sbit_t *bits, uint16_t nbits, int8_t rssi, float toa);
--
To view, visit https://gerrit.osmocom.org/6803
To unsubscribe, visit https://gerrit.osmocom.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: If6b0eaede2b484484d2a824e7219ff04483266a1
Gerrit-PatchSet: 1
Gerrit-Project: osmocom-bb
Gerrit-Branch: master
Gerrit-Owner: Harald Welte <laforge at gnumonks.org>