support for Ericsson RBS E1 CCU
Ericsson RBS series BTSs do not have a built in PCU. Rather than having
the PCU on board the PCU is co-located to the BSC in those cases. Just
like the MGW the PCU would connect to the CCU (Channel Coding Unit) via
E1 line. The PCU is connected via an unix domain socket (pcu_sock) to
the BSC to receive RACH requests and to control Paging and TBF assignment.
This patch adds all the required functionality to run an Ercisson RBS in
GPRS/EGPRS mode. It supports 16k I.460 E1 subslots and full 64k E1
timeslots (recommended)
Change-Id: I5c0a76667339ca984a12cbd2052f5d9e5b0f9c4d
Related: OS#5198
diff --git a/src/ericsson-rbs/er_ccu_if.c b/src/ericsson-rbs/er_ccu_if.c
new file mode 100644
index 0000000..aa659a3
--- /dev/null
+++ b/src/ericsson-rbs/er_ccu_if.c
@@ -0,0 +1,416 @@
+/*
+ * (C) 2022 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
+ * All Rights Reserved
+ *
+ * Author: Philipp Maier
+ *
+ * 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 Affero 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 <er_ccu_if.h>
+#include <er_ccu_descr.h>
+#include <string.h>
+#include <errno.h>
+
+#include <osmocom/abis/e1_input.h>
+#include <osmocom/abis/abis.h>
+#include <osmocom/trau/trau_sync.h>
+#include <osmocom/trau/trau_pcu_ericsson.h>
+#include <bts.h>
+#include <gprs_debug.h>
+#include <pcu_l1_if.h>
+
+#define E1_TS_BYTES 160
+#define DEBUG_BITS_MAX 1280
+#define DEBUG_BYTES_MAX 40
+
+#define LOGPCCU(ccu_descr, level, tag, fmt, args...) \
+ LOGP(DE1, level, "E1TS(%u:%u:%u) %s:" fmt, \
+ ccu_descr->e1_conn_pars->e1_nr, ccu_descr->e1_conn_pars->e1_ts, \
+ ccu_descr->e1_conn_pars->e1_ts_ss == E1_SUBSLOT_FULL ? 0 : ccu_descr->e1_conn_pars->e1_ts_ss, tag, \
+ ## args)
+
+struct e1_ts_descr {
+ uint8_t usecount;
+ bool i460_ts_initialized;
+ struct osmo_i460_timeslot i460_ts;
+};
+
+struct e1_line_descr {
+ struct e1_ts_descr e1_ts[NUM_E1_TS - 1];
+};
+
+static struct e1_line_descr e1_lines[32];
+static void *tall_ccu_ctx = NULL;
+
+static const struct e1inp_line_ops dummy_e1_line_ops = {
+ .sign_link_up = NULL,
+ .sign_link_down = NULL,
+ .sign_link = NULL,
+};
+
+/* called by trau frame synchronizer: feed received MAC blocks into PCU */
+static void sync_frame_out_cb(void *user_data, const ubit_t *bits, unsigned int num_bits)
+{
+ struct er_ccu_descr *ccu_descr = user_data;
+
+ if (!bits || num_bits == 0)
+ return;
+
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "I.460-RX", "receiving %u TRAU frame bits from subslot (synchronized): %s...\n",
+ num_bits, osmo_ubit_dump(bits, num_bits > DEBUG_BITS_MAX ? DEBUG_BITS_MAX : num_bits));
+
+ ccu_descr->er_ccu_rx_cb(ccu_descr, bits, num_bits);
+}
+
+/* called by I.460 de-multiplexer: feed output of I.460 demux into TRAU frame sync */
+static void e1_i460_demux_bits_cb(struct osmo_i460_subchan *schan, void *user_data, const ubit_t *bits,
+ unsigned int num_bits)
+{
+ struct er_ccu_descr *ccu_descr = user_data;
+
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "I.460-RX", "receiving %u TRAU frame bits from subslot: %s...\n", num_bits,
+ osmo_ubit_dump(bits, num_bits > DEBUG_BITS_MAX ? DEBUG_BITS_MAX : num_bits));
+
+ OSMO_ASSERT(ccu_descr->link.trau_sync_fi);
+ osmo_trau_sync_rx_ubits(ccu_descr->link.trau_sync_fi, bits, num_bits);
+
+}
+
+/* called by I.460 de-multiplexer: ensure that sync indications are sent when mux buffer runs empty */
+static void e1_i460_mux_empty_cb(struct osmo_i460_subchan *schan2, void *user_data)
+{
+ struct er_ccu_descr *ccu_descr = user_data;
+
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "I.460-TX", "demux buffer empty\n");
+ ccu_descr->er_ccu_empty_cb(ccu_descr);
+}
+
+/* handle outgoing E1 traffic */
+static void e1_send_ts_frame(struct e1inp_ts *ts)
+{
+ void *ctx = tall_ccu_ctx;
+ struct e1_ts_descr *ts_descr;
+ struct msgb *msg;
+ uint8_t *ptr;
+
+ /* The line number and ts number that arrives here should be clean. */
+ OSMO_ASSERT(ts->line->num < ARRAY_SIZE(e1_lines));
+
+ ts_descr = &e1_lines[ts->line->num].e1_ts[ts->num];
+
+ /* Do not send anything in case the E1 timeslot is not ready. */
+ if (ts_descr->usecount == 0)
+ return;
+
+ /* Get E1 frame from I.460 multiplexer */
+ msg = msgb_alloc_c(ctx, E1_TS_BYTES, "E1-TX-timeslot-bytes");
+ ptr = msgb_put(msg, E1_TS_BYTES);
+ osmo_i460_mux_out(&ts_descr->i460_ts, ptr, E1_TS_BYTES);
+
+ LOGPITS(ts, DE1, LOGL_DEBUG, "E1-TX: sending %u bytes: %s...\n",
+ msgb_length(msg), osmo_hexdump_nospc(msgb_data(msg),
+ msgb_length(msg) >
+ DEBUG_BYTES_MAX ? DEBUG_BYTES_MAX : msgb_length(msg)));
+
+ /* Hand data over to the E1 stack */
+ msgb_enqueue(&ts->raw.tx_queue, msg);
+}
+
+/* Callback function to handle incoming E1 traffic */
+static void e1_recv_cb(struct e1inp_ts *ts, struct msgb *msg)
+{
+ struct e1_ts_descr *ts_descr;
+
+ if (msg->len != E1_TS_BYTES) {
+ LOGPITS(ts, DE1, LOGL_ERROR,
+ "E1-RX: receiving bad, expected length is %u, actual length is %u!\n",
+ E1_TS_BYTES, msg->len);
+ msgb_free(msg);
+ return;
+ }
+
+ LOGPITS(ts, DE1, LOGL_DEBUG, "E1-RX: receiving %u bytes: %s ...\n",
+ msg->len, osmo_hexdump_nospc(msg->data, msg->len));
+
+ /* Note: The line number and ts number that arrives here should be clean. */
+ OSMO_ASSERT(ts->line->num < ARRAY_SIZE(e1_lines));
+ ts_descr = &e1_lines[ts->line->num].e1_ts[ts->num];
+
+ /* Hand data over to the I640 demultiplexer. */
+ osmo_i460_demux_in(&ts_descr->i460_ts, msg->data, msg->len);
+
+ /* Trigger sending of pending E1 traffic */
+ e1_send_ts_frame(ts);
+
+ /* e1inp_rx_ts(), the caller of this callback does not free() msgb. */
+ msgb_free(msg);
+}
+
+static struct e1_ts_descr *ts_descr_from_ccu_descr(struct er_ccu_descr *ccu_descr)
+{
+ /* Make sure E1 line number is valid */
+ if (ccu_descr->e1_conn_pars->e1_nr >= ARRAY_SIZE(e1_lines)) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "Invalid E1 line number!\n");
+ return NULL;
+ }
+
+ /* Make sure E1 timeslot number is valid */
+ if (ccu_descr->e1_conn_pars->e1_ts < 1 || ccu_descr->e1_conn_pars->e1_ts > NUM_E1_TS - 1) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "Invalid E1 timeslot number!\n");
+ return NULL;
+ }
+
+ /* Timeslots are only initialized once and will stay open after that. */
+ return &e1_lines[ccu_descr->e1_conn_pars->e1_nr].e1_ts[ccu_descr->e1_conn_pars->e1_ts];
+}
+
+/* Configure an I.460 subslot and add it to the CCU descriptor */
+static int add_i460_subslot(void *ctx, struct er_ccu_descr *ccu_descr)
+{
+ struct e1_ts_descr *ts_descr;
+ enum osmo_tray_sync_pat_id sync_pattern;
+
+ if (ccu_descr->link.schan) {
+ /* NOTE: This is a serious error: subslots should be removed when l1if_close_pdch() is called by the
+ * PCU. This log line points towards a problem with the PDCH management inside the PCU! */
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "I.460 subslot is already configured -- will not touch it!\n");
+ return -EINVAL;
+ }
+
+ ts_descr = ts_descr_from_ccu_descr(ccu_descr);
+ if (!ts_descr)
+ return -EINVAL;
+ if (ts_descr->usecount == 0) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "E1 timeslot not ready!\n");
+ return -EINVAL;
+ }
+
+ /* Set up I.460 subchannel and connect it to the MUX on the E1 timeslot */
+ if (ccu_descr->e1_conn_pars->e1_ts_ss == E1_SUBSLOT_FULL) {
+ LOGPCCU(ccu_descr, LOGL_INFO, "SETUP", "using 64k subslots\n");
+ ccu_descr->link.scd.rate = OSMO_I460_RATE_64k;
+ ccu_descr->link.scd.demux.num_bits = E1_TS_BYTES * 8;
+ ccu_descr->link.scd.bit_offset = 0;
+ sync_pattern = OSMO_TRAU_SYNCP_64_ER_CCU;
+ } else {
+ LOGPCCU(ccu_descr, LOGL_INFO, "SETUP", "using 16k subslots\n");
+ if (ccu_descr->e1_conn_pars->e1_ts_ss > 3) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "Invalid I.460 subslot number!\n");
+ return -EINVAL;
+ }
+ ccu_descr->link.scd.rate = OSMO_I460_RATE_16k;
+ ccu_descr->link.scd.demux.num_bits = E1_TS_BYTES / 4 * 8;
+ ccu_descr->link.scd.bit_offset = ccu_descr->e1_conn_pars->e1_ts_ss * 2;
+ sync_pattern = OSMO_TRAU_SYNCP_16_ER_CCU;
+ }
+
+ ccu_descr->link.scd.demux.out_cb_bits = e1_i460_demux_bits_cb;
+ ccu_descr->link.scd.demux.out_cb_bytes = NULL;
+ ccu_descr->link.scd.demux.user_data = ccu_descr;
+ ccu_descr->link.scd.mux.in_cb_queue_empty = e1_i460_mux_empty_cb;
+ ccu_descr->link.scd.mux.user_data = ccu_descr;
+
+ LOGPCCU(ccu_descr, LOGL_INFO, "SETUP", "adding I.460 subchannel: bit_offset=%u, num_bits=%zu\n",
+ ccu_descr->link.scd.bit_offset, ccu_descr->link.scd.demux.num_bits);
+ ccu_descr->link.schan = osmo_i460_subchan_add(ctx, &ts_descr->i460_ts, &ccu_descr->link.scd);
+ if (!ccu_descr->link.schan) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "adding I.460 subchannel: failed!\n");
+ return -EINVAL;
+ }
+
+ /* Configure TRAU synchronizer */
+ ccu_descr->link.trau_sync_fi = osmo_trau_sync_alloc(tall_ccu_ctx, "trau-sync", sync_frame_out_cb, sync_pattern, ccu_descr);
+ if (!ccu_descr->link.trau_sync_fi) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "adding I.460 TRAU frame sync: failed!\n");
+ return -EINVAL;
+ }
+
+ /* Ericsson uses a different synchronization pattern for MCS9 TRAU frames */
+ if (sync_pattern == OSMO_TRAU_SYNCP_64_ER_CCU)
+ osmo_trau_sync_set_secondary_pat(ccu_descr->link.trau_sync_fi, OSMO_TRAU_SYNCP_64_ER_CCU_MCS9, 1);
+
+ return 0;
+}
+
+/* Remove an I.460 subslot from the CCU descriptor */
+static void del_i460_subslot(struct er_ccu_descr *ccu_descr)
+{
+ if (ccu_descr->link.schan)
+ osmo_i460_subchan_del(ccu_descr->link.schan);
+ ccu_descr->link.schan = NULL;
+ if (ccu_descr->link.trau_sync_fi)
+ osmo_fsm_inst_term(ccu_descr->link.trau_sync_fi, OSMO_FSM_TERM_REGULAR, NULL);
+ ccu_descr->link.trau_sync_fi = NULL;
+
+ memset(&ccu_descr->link.scd, 0, sizeof(ccu_descr->link.scd));
+}
+
+/* Configure an E1 timeslot according to the description in the ccu_descr */
+static int open_e1_timeslot(struct er_ccu_descr *ccu_descr)
+{
+ struct e1inp_line *e1_line;
+ struct e1_ts_descr *ts_descr;
+ int rc;
+
+ /* Find timeslot descriptor and check if the timeslot is already open. */
+ ts_descr = ts_descr_from_ccu_descr(ccu_descr);
+ if (!ts_descr)
+ return -EINVAL;
+ if (ts_descr->usecount > 0) {
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "SETUP", "E1 timeslot already open -- using it as it is!\n");
+ ts_descr->usecount++;
+ return 0;
+ }
+
+ /* Find and set up E1 line */
+ e1_line = e1inp_line_find(ccu_descr->e1_conn_pars->e1_nr);
+ if (!e1_line) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "no such E1 line!\n");
+ return -EINVAL;
+ }
+ e1inp_line_bind_ops(e1_line, &dummy_e1_line_ops);
+
+ /* Set up E1 timeslot */
+ rc = e1inp_ts_config_raw(&e1_line->ts[ccu_descr->e1_conn_pars->e1_ts - 1], e1_line, e1_recv_cb);
+ if (rc < 0) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "configuration of timeslot failed!\n");
+ return -EINVAL;
+ }
+ rc = e1inp_line_update(e1_line);
+ if (rc < 0) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "line update failed!\n");
+ return -EINVAL;
+ }
+
+ /* Make sure the i460 mux is ready */
+ if (!ts_descr->i460_ts_initialized) {
+ osmo_i460_ts_init(&ts_descr->i460_ts);
+ ts_descr->i460_ts_initialized = true;
+ }
+
+ ts_descr->usecount++;
+ OSMO_ASSERT(ts_descr->usecount == 1);
+
+ return 0;
+}
+
+/* Configure an E1 timeslot according to the description in the ccu_descr */
+static int close_e1_timeslot(struct er_ccu_descr *ccu_descr)
+{
+ struct e1inp_line *e1_line;
+ struct e1_ts_descr *ts_descr;
+ int rc;
+
+ /* Find timeslot descriptor and check if the timeslot is still used by another subslot. */
+ ts_descr = ts_descr_from_ccu_descr(ccu_descr);
+ if (!ts_descr)
+ return -EINVAL;
+ if (ts_descr->usecount > 1) {
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "SETUP",
+ "E1 timeslot still in used by another subslot, leaving it open!\n");
+ ts_descr->usecount--;
+ return 0;
+ } else if (ts_descr->usecount == 0) {
+ /* This should not be as it means we close the timeslot too often. */
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "E1 timeslot already closed, leaving it as it is...\n");
+ return -EINVAL;
+ }
+
+ /* Find E1 line */
+ e1_line = e1inp_line_find(ccu_descr->e1_conn_pars->e1_nr);
+ if (!e1_line) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "no such E1 line!\n");
+ return -EINVAL;
+ }
+
+ /* Release E1 timeslot */
+ rc = e1inp_ts_config_none(&e1_line->ts[ccu_descr->e1_conn_pars->e1_ts - 1], e1_line);
+ if (rc < 0) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "failed to disable E1 timeslot!\n");
+ return -EINVAL;
+ }
+ rc = e1inp_line_update(e1_line);
+ if (rc < 0) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "failed to update E1 line!\n");
+ return -EINVAL;
+ }
+
+ ts_descr->usecount--;
+ OSMO_ASSERT(ts_descr->usecount == 0);
+
+ return 0;
+}
+
+int er_ccu_if_open(struct er_ccu_descr *ccu_descr)
+{
+ if (ccu_descr->link.ccu_connected) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP",
+ "cannot connect CCU since it is already connected -- ignored!\n");
+ return 0;
+ }
+
+ if (open_e1_timeslot(ccu_descr) < 0)
+ return -EINVAL;
+
+ if (add_i460_subslot(tall_ccu_ctx, ccu_descr) < 0)
+ return -EINVAL;
+
+ ccu_descr->link.ccu_connected = true;
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "SETUP", "CCU connected.\n");
+ return 0;
+}
+
+void er_ccu_if_close(struct er_ccu_descr *ccu_descr)
+{
+ if (!ccu_descr->link.ccu_connected) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP",
+ "cannot disconnect CCU since it is already disconnected -- ignored!\n");
+ return;
+ }
+
+ del_i460_subslot(ccu_descr);
+ close_e1_timeslot(ccu_descr);
+
+ ccu_descr->link.ccu_connected = false;
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "SETUP", "CCU disconnected.\n");
+}
+
+void er_ccu_if_tx(struct er_ccu_descr *ccu_descr, const ubit_t *bits, unsigned int num_bits)
+{
+ struct msgb *msg;
+ uint8_t *ptr;
+
+ if (!ccu_descr->link.ccu_connected) {
+ LOGPCCU(ccu_descr, LOGL_ERROR, "SETUP", "cannot TX block, CCU is disconnected -- ignored!\n");
+ return;
+ }
+
+ msg = msgb_alloc_c(tall_ccu_ctx, num_bits, "E1-I.460-PCU-IND-frame");
+ ptr = msgb_put(msg, num_bits);
+ memcpy(ptr, bits, num_bits);
+ LOGPCCU(ccu_descr, LOGL_DEBUG, "I.460-TX", "sending %u bits: %s...\n", msgb_length(msg),
+ osmo_ubit_dump(msgb_data(msg), msgb_length(msg) > DEBUG_BITS_MAX ? DEBUG_BITS_MAX : msgb_length(msg)));
+ osmo_i460_mux_enqueue(ccu_descr->link.schan, msg);
+}
+
+void er_ccu_if_init(void *ctx)
+{
+ libosmo_abis_init(ctx);
+ e1inp_vty_init();
+
+ tall_ccu_ctx = talloc_new(ctx);
+ memset(e1_lines, 0, sizeof(e1_lines));
+}