| /* |
| * 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 <talloc.h> |
| #include <stdint.h> |
| |
| #include <arpa/inet.h> |
| |
| #include <osmocom/core/logging.h> |
| #include <osmocom/core/bits.h> |
| |
| #include <osmocom/gsm/gsm_utils.h> |
| #include <osmocom/coding/gsm0503_coding.h> |
| |
| #include "l1ctl_proto.h" |
| #include "scheduler.h" |
| #include "sched_trx.h" |
| #include "logging.h" |
| #include "trx_if.h" |
| #include "l1ctl.h" |
| |
| __attribute__((xray_always_instrument)) __attribute__((noinline)) |
| static int gsm0503_sch_decode_xray(uint8_t *sb_info, const sbit_t *burst) |
| { |
| return gsm0503_sch_decode(sb_info, burst); |
| } |
| |
| static void decode_sb(struct gsm_time *time, uint8_t *bsic, uint8_t *sb_info) |
| { |
| uint8_t t3p; |
| uint32_t sb; |
| |
| sb = ((uint32_t)sb_info[3] << 24) |
| | (sb_info[2] << 16) |
| | (sb_info[1] << 8) |
| | sb_info[0]; |
| |
| *bsic = (sb >> 2) & 0x3f; |
| |
| /* TS 05.02 Chapter 3.3.2.2.1 SCH Frame Numbers */ |
| time->t1 = ((sb >> 23) & 0x01) |
| | ((sb >> 7) & 0x1fe) |
| | ((sb << 9) & 0x600); |
| |
| time->t2 = (sb >> 18) & 0x1f; |
| |
| t3p = ((sb >> 24) & 0x01) | ((sb >> 15) & 0x06); |
| time->t3 = t3p * 10 + 1; |
| |
| /* TS 05.02 Chapter 4.3.3 TDMA frame number */ |
| time->fn = gsm_gsmtime2fn(time); |
| } |
| |
| int rx_sch_fn(struct trx_instance *trx, struct trx_ts *ts, |
| struct trx_lchan_state *lchan, uint32_t fn, uint8_t bid, |
| const sbit_t *bits, const struct trx_meas_set *meas) |
| { |
| sbit_t payload[2 * 39]; |
| struct gsm_time time; |
| uint8_t sb_info[4]; |
| uint8_t bsic; |
| int rc; |
| |
| /* Obtain payload from burst */ |
| memcpy(payload, bits + 3, 39); |
| memcpy(payload + 39, bits + 3 + 39 + 64, 39); |
| |
| /* Attempt to decode */ |
| rc = gsm0503_sch_decode_xray(sb_info, payload); |
| if (rc) { |
| LOGP(DSCHD, LOGL_ERROR, "Received bad SCH burst at fn=%u\n", fn); |
| return rc; |
| } |
| |
| /* Decode BSIC and TDMA frame number */ |
| decode_sb(&time, &bsic, sb_info); |
| |
| LOGP(DSCHD, LOGL_DEBUG, "Received SCH: bsic=%u, fn=%u, sched_fn=%u\n", |
| bsic, time.fn, trx->sched.fn_counter_proc); |
| |
| /* Check if decoded frame number matches */ |
| if (time.fn != fn) { |
| LOGP(DSCHD, LOGL_ERROR, "Decoded fn=%u does not match " |
| "fn=%u provided by scheduler\n", time.fn, fn); |
| return -EINVAL; |
| } |
| |
| /* We don't need to send L1CTL_FBSB_CONF */ |
| if (trx->l1l->fbsb_conf_sent) |
| return 0; |
| |
| /* Send L1CTL_FBSB_CONF to higher layers */ |
| struct l1ctl_info_dl *data; |
| data = talloc_zero_size(ts, sizeof(struct l1ctl_info_dl)); |
| if (data == NULL) |
| return -ENOMEM; |
| |
| /* Fill in some downlink info */ |
| data->chan_nr = trx_lchan_desc[lchan->type].chan_nr | ts->index; |
| data->link_id = trx_lchan_desc[lchan->type].link_id; |
| data->band_arfcn = htons(trx->band_arfcn); |
| data->frame_nr = htonl(fn); |
| data->rx_level = -(meas->rssi); |
| |
| /* FIXME: set proper values */ |
| data->num_biterr = 0; |
| data->fire_crc = 0; |
| data->snr = 0; |
| |
| l1ctl_tx_fbsb_conf(trx->l1l, 0, data, bsic); |
| |
| /* Update BSIC value of trx_instance */ |
| trx->bsic = bsic; |
| |
| return 0; |
| } |