585 lines
16 KiB
C
585 lines
16 KiB
C
/*
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* OsmocomBB <-> SDR connection bridge
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* TDMA scheduler: handlers for DL / UL bursts on logical channels
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*
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* (C) 2018-2022 by Vadim Yanitskiy <axilirator@gmail.com>
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* (C) 2018 by Harald Welte <laforge@gnumonks.org>
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* Contributions by sysmocom - s.f.m.c. GmbH
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <errno.h>
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#include <string.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <osmocom/core/logging.h>
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#include <osmocom/core/utils.h>
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#include <osmocom/core/bits.h>
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#include <osmocom/gsm/protocol/gsm_04_08.h>
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#include <osmocom/gsm/gsm_utils.h>
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#include <osmocom/coding/gsm0503_coding.h>
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#include <osmocom/coding/gsm0503_amr_dtx.h>
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#include <osmocom/codec/codec.h>
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#include <osmocom/bb/l1sched/l1sched.h>
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#include <osmocom/bb/l1sched/logging.h>
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/* 3GPP TS 45.009, table 3.2.1.3-{2,4}: AMR on Downlink TCH/H.
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*
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* +---+---+---+---+---+---+
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* | a | b | c | d | e | f | Burst 'a' received first
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* +---+---+---+---+---+---+
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* ^^^^^^^^^^^^^^^^^^^^^^^ FACCH frame (bursts 'a' .. 'f')
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* ^^^^^^^^^^^^^^^ Speech frame (bursts 'a' .. 'd')
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*
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* TDMA frame number of burst 'f' is always used as the table index. */
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static const uint8_t sched_tchh_dl_amr_cmi_map[26] = {
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[15] = 1, /* TCH/H(0): a=4 / d=10 / f=15 */
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[23] = 1, /* TCH/H(0): a=13 / d=19 / f=23 */
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[6] = 1, /* TCH/H(0): a=21 / d=2 / f=6 */
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[16] = 1, /* TCH/H(1): a=5 / d=11 / f=16 */
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[24] = 1, /* TCH/H(1): a=14 / d=20 / f=24 */
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[7] = 1, /* TCH/H(1): a=22 / d=3 / f=7 */
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};
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/* TDMA frame number of burst 'a' is always used as the table index. */
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static const uint8_t sched_tchh_ul_amr_cmi_map[26] = {
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[0] = 1, /* TCH/H(0): a=0 */
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[8] = 1, /* TCH/H(0): a=8 */
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[17] = 1, /* TCH/H(0): a=17 */
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[1] = 1, /* TCH/H(1): a=1 */
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[9] = 1, /* TCH/H(1): a=9 */
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[18] = 1, /* TCH/H(1): a=18 */
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};
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static const uint8_t tch_h0_traffic_block_map[3][4] = {
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/* B0(0,2,4,6), B1(4,6,8,10), B2(8,10,0,2) */
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{ 0, 2, 4, 6 },
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{ 4, 6, 8, 10 },
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{ 8, 10, 0, 2 },
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};
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static const uint8_t tch_h1_traffic_block_map[3][4] = {
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/* B0(1,3,5,7), B1(5,7,9,11), B2(9,11,1,3) */
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{ 1, 3, 5, 7 },
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{ 5, 7, 9, 11 },
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{ 9, 11, 1, 3 },
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};
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static const uint8_t tch_h0_dl_facch_block_map[3][6] = {
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/* B0(4,6,8,10,13,15), B1(13,15,17,19,21,23), B2(21,23,0,2,4,6) */
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{ 4, 6, 8, 10, 13, 15 },
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{ 13, 15, 17, 19, 21, 23 },
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{ 21, 23, 0, 2, 4, 6 },
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};
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static const uint8_t tch_h0_ul_facch_block_map[3][6] = {
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/* B0(0,2,4,6,8,10), B1(8,10,13,15,17,19), B2(17,19,21,23,0,2) */
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{ 0, 2, 4, 6, 8, 10 },
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{ 8, 10, 13, 15, 17, 19 },
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{ 17, 19, 21, 23, 0, 2 },
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};
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static const uint8_t tch_h1_dl_facch_block_map[3][6] = {
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/* B0(5,7,9,11,14,16), B1(14,16,18,20,22,24), B2(22,24,1,3,5,7) */
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{ 5, 7, 9, 11, 14, 16 },
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{ 14, 16, 18, 20, 22, 24 },
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{ 22, 24, 1, 3, 5, 7 },
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};
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const uint8_t tch_h1_ul_facch_block_map[3][6] = {
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/* B0(1,3,5,7,9,11), B1(9,11,14,16,18,20), B2(18,20,22,24,1,3) */
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{ 1, 3, 5, 7, 9, 11 },
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{ 9, 11, 14, 16, 18, 20 },
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{ 18, 20, 22, 24, 1, 3 },
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};
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/* FACCH/H channel mapping for Downlink (see 3GPP TS 45.002, table 1).
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* This mapping is valid for both FACCH/H(0) and FACCH/H(1).
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* TDMA frame number of burst 'f' is used as the table index. */
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static const uint8_t sched_tchh_dl_facch_map[26] = {
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[15] = 1, /* FACCH/H(0): B0(4,6,8,10,13,15) */
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[16] = 1, /* FACCH/H(1): B0(5,7,9,11,14,16) */
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[23] = 1, /* FACCH/H(0): B1(13,15,17,19,21,23) */
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[24] = 1, /* FACCH/H(1): B1(14,16,18,20,22,24) */
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[6] = 1, /* FACCH/H(0): B2(21,23,0,2,4,6) */
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[7] = 1, /* FACCH/H(1): B2(22,24,1,3,5,7) */
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};
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/**
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* Can a TCH/H block transmission be initiated / finished
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* on a given frame number and a given channel type?
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*
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* See GSM 05.02, clause 7, table 1
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*
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* @param chan channel type (L1SCHED_TCHH_0 or L1SCHED_TCHH_1)
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* @param fn the current frame number
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* @param ul Uplink or Downlink?
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* @param facch FACCH/H or traffic?
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* @param start init or end of transmission?
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* @return true (yes) or false (no)
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*/
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bool l1sched_tchh_block_map_fn(enum l1sched_lchan_type chan,
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uint32_t fn, bool ul, bool facch, bool start)
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{
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uint8_t fn_mf;
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int i = 0;
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/* Just to be sure */
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OSMO_ASSERT(chan == L1SCHED_TCHH_0 || chan == L1SCHED_TCHH_1);
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/* Calculate a modulo */
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fn_mf = facch ? (fn % 26) : (fn % 13);
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#define MAP_GET_POS(map) \
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(start ? 0 : ARRAY_SIZE(map[i]) - 1)
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#define BLOCK_MAP_FN(map) \
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do { \
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if (map[i][MAP_GET_POS(map)] == fn_mf) \
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return true; \
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} while (++i < ARRAY_SIZE(map))
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/* Choose a proper block map */
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if (facch) {
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if (ul) {
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if (chan == L1SCHED_TCHH_0)
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BLOCK_MAP_FN(tch_h0_ul_facch_block_map);
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else
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BLOCK_MAP_FN(tch_h1_ul_facch_block_map);
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} else {
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if (chan == L1SCHED_TCHH_0)
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BLOCK_MAP_FN(tch_h0_dl_facch_block_map);
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else
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BLOCK_MAP_FN(tch_h1_dl_facch_block_map);
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}
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} else {
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if (chan == L1SCHED_TCHH_0)
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BLOCK_MAP_FN(tch_h0_traffic_block_map);
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else
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BLOCK_MAP_FN(tch_h1_traffic_block_map);
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}
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return false;
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}
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/**
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* Calculates a frame number of the first burst
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* using given frame number of the last burst.
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*
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* See GSM 05.02, clause 7, table 1
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*
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* @param chan channel type (L1SCHED_TCHH_0 or L1SCHED_TCHH_1)
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* @param last_fn frame number of the last burst
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* @param facch FACCH/H or traffic?
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* @return either frame number of the first burst,
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* or fn=last_fn if calculation failed
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*/
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static uint32_t tchh_block_dl_first_fn(const struct l1sched_lchan_state *lchan,
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uint32_t last_fn, bool facch)
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{
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enum l1sched_lchan_type chan = lchan->type;
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uint8_t fn_mf, fn_diff;
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int i = 0;
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/* Just to be sure */
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OSMO_ASSERT(chan == L1SCHED_TCHH_0 || chan == L1SCHED_TCHH_1);
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/* Calculate a modulo */
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fn_mf = facch ? (last_fn % 26) : (last_fn % 13);
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#define BLOCK_FIRST_FN(map) \
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do { \
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if (map[i][ARRAY_SIZE(map[i]) - 1] == fn_mf) { \
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fn_diff = GSM_TDMA_FN_DIFF(fn_mf, map[i][0]); \
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return GSM_TDMA_FN_SUB(last_fn, fn_diff); \
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} \
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} while (++i < ARRAY_SIZE(map))
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/* Choose a proper block map */
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if (facch) {
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if (chan == L1SCHED_TCHH_0)
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BLOCK_FIRST_FN(tch_h0_dl_facch_block_map);
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else
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BLOCK_FIRST_FN(tch_h1_dl_facch_block_map);
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} else {
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if (chan == L1SCHED_TCHH_0)
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BLOCK_FIRST_FN(tch_h0_traffic_block_map);
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else
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BLOCK_FIRST_FN(tch_h1_traffic_block_map);
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}
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LOGP_LCHAND(lchan, LOGL_ERROR,
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"Failed to calculate TDMA frame number of the first burst of %s block, "
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"using the current fn=%u\n", facch ? "FACCH/H" : "TCH/H", last_fn);
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/* Couldn't calculate the first fn, return the last */
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return last_fn;
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}
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int rx_tchh_fn(struct l1sched_lchan_state *lchan,
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const struct l1sched_burst_ind *bi)
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{
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int n_errors = -1, n_bits_total = 0, rc;
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sbit_t *buffer, *offset;
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uint8_t l2[128], *mask;
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size_t l2_len;
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int amr = 0;
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uint8_t ft;
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bool fn_is_cmi;
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/* Set up pointers */
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mask = &lchan->rx_burst_mask;
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buffer = lchan->rx_bursts;
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LOGP_LCHAND(lchan, LOGL_DEBUG,
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"Traffic received: fn=%u bid=%u\n", bi->fn, bi->bid);
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if (*mask == 0x00) {
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/* Align to the first burst */
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if (bi->bid > 0)
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return 0;
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/* Align reception of the first FACCH/H frame */
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if (lchan->tch_mode == GSM48_CMODE_SIGN) {
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if (!l1sched_tchh_facch_start(lchan->type, bi->fn, 0))
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return 0;
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} else { /* or TCH/H traffic frame */
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if (!l1sched_tchh_traffic_start(lchan->type, bi->fn, 0))
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return 0;
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}
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}
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/* Update mask */
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*mask |= (1 << bi->bid);
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/* Store the measurements */
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l1sched_lchan_meas_push(lchan, bi);
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/* Copy burst to the end of buffer of 6 bursts */
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offset = buffer + bi->bid * 116 + 464;
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memcpy(offset, bi->burst + 3, 58);
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memcpy(offset + 58, bi->burst + 87, 58);
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/* Wait until the second burst */
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if (bi->bid != 1)
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return 0;
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/* Wait for complete set of bursts */
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if (lchan->tch_mode == GSM48_CMODE_SIGN) {
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/* FACCH/H is interleaved over 6 bursts */
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if ((*mask & 0x3f) != 0x3f)
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goto bfi_shift;
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} else {
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/* Traffic is interleaved over 4 bursts */
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if ((*mask & 0x0f) != 0x0f)
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goto bfi_shift;
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}
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/* Skip decoding attempt in case of FACCH/H */
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if (lchan->dl_ongoing_facch) {
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lchan->dl_ongoing_facch = false;
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goto bfi_shift; /* 2/2 BFI */
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}
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switch (lchan->tch_mode) {
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case GSM48_CMODE_SIGN:
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case GSM48_CMODE_SPEECH_V1: /* HR */
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rc = gsm0503_tch_hr_decode(l2, buffer,
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!l1sched_tchh_facch_end(lchan->type, bi->fn, 0),
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&n_errors, &n_bits_total);
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break;
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case GSM48_CMODE_SPEECH_AMR: /* AMR */
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/* the first FN FN 4,13,21 or 5,14,22 defines that CMI is
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* included in frame, the first FN FN 0,8,17 or 1,9,18 defines
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* that CMR/CMC is included in frame. */
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fn_is_cmi = sched_tchh_dl_amr_cmi_map[bi->fn % 26];
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/* See comment in function rx_tchf_fn() */
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amr = 2;
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rc = gsm0503_tch_ahs_decode_dtx(l2 + amr, buffer,
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!sched_tchh_dl_facch_map[bi->fn % 26],
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!fn_is_cmi, lchan->amr.codec, lchan->amr.codecs, &lchan->amr.dl_ft,
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&lchan->amr.dl_cmr, &n_errors, &n_bits_total, &lchan->amr.last_dtx);
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/* only good speech frames get rtp header */
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if (rc != GSM_MACBLOCK_LEN && rc >= 4) {
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if (lchan->amr.last_dtx == AMR_OTHER) {
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ft = lchan->amr.codec[lchan->amr.dl_ft];
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} else {
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/* SID frames will always get Frame Type Index 8 (AMR_SID) */
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ft = AMR_SID;
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}
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rc = osmo_amr_rtp_enc(l2,
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lchan->amr.codec[lchan->amr.dl_cmr],
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ft, AMR_GOOD);
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if (rc < 0)
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LOGP_LCHAND(lchan, LOGL_ERROR,
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"osmo_amr_rtp_enc() returned rc=%d\n", rc);
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}
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break;
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default:
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LOGP_LCHAND(lchan, LOGL_ERROR, "Invalid TCH mode: %u\n", lchan->tch_mode);
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return -EINVAL;
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}
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/* Shift buffer by 4 bursts for interleaving */
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memcpy(buffer, buffer + 232, 232);
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memcpy(buffer + 232, buffer + 464, 232);
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/* Shift burst mask */
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*mask = *mask << 2;
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/* Check decoding result */
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if (rc < 4) {
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/* Calculate AVG of the measurements (assuming 4 bursts) */
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l1sched_lchan_meas_avg(lchan, 4);
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LOGP_LCHAND(lchan, LOGL_ERROR,
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"Received bad frame (rc=%d, ber=%d/%d) at fn=%u\n",
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rc, n_errors, n_bits_total, lchan->meas_avg.fn);
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/* Send BFI */
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goto bfi;
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} else if (rc == GSM_MACBLOCK_LEN) {
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/* Skip decoding of the next 2 stolen bursts */
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lchan->dl_ongoing_facch = true;
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/* Calculate AVG of the measurements (FACCH/H takes 6 bursts) */
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l1sched_lchan_meas_avg(lchan, 6);
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/* FACCH/H received, forward to the higher layers */
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l1sched_lchan_emit_data_ind(lchan, l2 + amr, GSM_MACBLOCK_LEN,
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n_errors, n_bits_total, false);
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/* Send BFI substituting 1/2 stolen TCH frames */
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n_errors = -1; /* ensure fake measurements */
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goto bfi;
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} else {
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/* A good TCH frame received */
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l2_len = rc;
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/* Calculate AVG of the measurements (traffic takes 4 bursts) */
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l1sched_lchan_meas_avg(lchan, 4);
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}
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/* Send a traffic frame to the higher layers */
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return l1sched_lchan_emit_data_ind(lchan, l2, l2_len,
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n_errors, n_bits_total, true);
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bfi_shift:
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/* Shift buffer */
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memcpy(buffer, buffer + 232, 232);
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memcpy(buffer + 232, buffer + 464, 232);
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/* Shift burst mask */
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*mask = *mask << 2;
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bfi:
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/* Didn't try to decode, fake measurements */
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if (n_errors < 0) {
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lchan->meas_avg = (struct l1sched_meas_set) {
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.fn = tchh_block_dl_first_fn(lchan, bi->fn, false),
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.toa256 = 0,
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.rssi = -110,
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};
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/* No bursts => no errors */
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n_errors = 0;
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}
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/* BFI is not applicable in signalling mode */
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if (lchan->tch_mode == GSM48_CMODE_SIGN) {
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return l1sched_lchan_emit_data_ind(lchan, NULL, 0,
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n_errors, n_bits_total, false);
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}
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/* Bad frame indication */
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l2_len = l1sched_bad_frame_ind(l2, lchan);
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/* Send a BFI frame to the higher layers */
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return l1sched_lchan_emit_data_ind(lchan, l2, l2_len,
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n_errors, n_bits_total, true);
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}
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int tx_tchh_fn(struct l1sched_lchan_state *lchan,
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struct l1sched_burst_req *br)
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{
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ubit_t *buffer, *offset;
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const uint8_t *tsc;
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uint8_t *mask;
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size_t l2_len;
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int rc;
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/* Set up pointers */
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mask = &lchan->tx_burst_mask;
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buffer = lchan->tx_bursts;
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if (br->bid > 0) {
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/* Align to the first burst */
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if (*mask == 0x00)
|
|
return 0;
|
|
goto send_burst;
|
|
}
|
|
|
|
if (*mask == 0x00) {
|
|
/* Align transmission of the first FACCH/H frame */
|
|
if (lchan->tch_mode == GSM48_CMODE_SIGN)
|
|
if (!l1sched_tchh_facch_start(lchan->type, br->fn, 1))
|
|
return 0;
|
|
}
|
|
|
|
/* Shift buffer by 2 bursts back for interleaving */
|
|
memcpy(buffer, buffer + 232, 232);
|
|
|
|
/* Also shift TX burst mask */
|
|
*mask = *mask << 2;
|
|
|
|
/* If FACCH/H blocks are still pending */
|
|
if (lchan->ul_facch_blocks > 2) {
|
|
memcpy(buffer + 232, buffer + 464, 232);
|
|
goto send_burst;
|
|
}
|
|
|
|
/* populate the buffer with bursts */
|
|
if (msgb_l2len(lchan->prim) == GSM_MACBLOCK_LEN) {
|
|
rc = gsm0503_tch_hr_encode(buffer, msgb_l2(lchan->prim), GSM_MACBLOCK_LEN);
|
|
lchan->ul_facch_blocks = 6;
|
|
} else if (lchan->tch_mode == GSM48_CMODE_SPEECH_AMR) {
|
|
int len;
|
|
uint8_t cmr_codec;
|
|
int ft, cmr, i;
|
|
enum osmo_amr_type ft_codec;
|
|
enum osmo_amr_quality bfi;
|
|
int8_t sti, cmi;
|
|
bool amr_fn_is_cmr;
|
|
/* 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.
|
|
*/
|
|
amr_fn_is_cmr = !sched_tchh_ul_amr_cmi_map[br->fn % 26];
|
|
|
|
len = osmo_amr_rtp_dec(msgb_l2(lchan->prim), msgb_l2len(lchan->prim),
|
|
&cmr_codec, &cmi, &ft_codec, &bfi, &sti);
|
|
if (len < 0) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR, "Cannot send invalid AMR payload (%u): %s\n",
|
|
msgb_l2len(lchan->prim), msgb_hexdump_l2(lchan->prim));
|
|
goto free_bad_msg;
|
|
}
|
|
ft = -1;
|
|
cmr = -1;
|
|
for (i = 0; i < lchan->amr.codecs; i++) {
|
|
if (lchan->amr.codec[i] == ft_codec)
|
|
ft = i;
|
|
if (lchan->amr.codec[i] == cmr_codec)
|
|
cmr = i;
|
|
}
|
|
if (ft < 0) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR,
|
|
"Codec (FT = %d) of RTP frame not in list\n", ft_codec);
|
|
goto free_bad_msg;
|
|
}
|
|
if (amr_fn_is_cmr && lchan->amr.ul_ft != ft) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR,
|
|
"Codec (FT = %d) of RTP cannot be changed now, but in next frame\n",
|
|
ft_codec);
|
|
goto free_bad_msg;
|
|
}
|
|
lchan->amr.ul_ft = ft;
|
|
if (cmr < 0) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR,
|
|
"Codec (CMR = %d) of RTP frame not in list\n", cmr_codec);
|
|
} else {
|
|
lchan->amr.ul_cmr = cmr;
|
|
}
|
|
rc = gsm0503_tch_ahs_encode(buffer,
|
|
msgb_l2(lchan->prim) + 2,
|
|
msgb_l2len(lchan->prim) - 2,
|
|
amr_fn_is_cmr,
|
|
lchan->amr.codec,
|
|
lchan->amr.codecs,
|
|
lchan->amr.ul_ft,
|
|
lchan->amr.ul_cmr);
|
|
} else {
|
|
/* Determine and check the payload length */
|
|
switch (lchan->tch_mode) {
|
|
case GSM48_CMODE_SIGN:
|
|
case GSM48_CMODE_SPEECH_V1: /* HR */
|
|
l2_len = GSM_HR_BYTES + 1;
|
|
break;
|
|
default:
|
|
LOGP_LCHAND(lchan, LOGL_ERROR,
|
|
"Invalid TCH mode: %u, dropping frame...\n",
|
|
lchan->tch_mode);
|
|
l1sched_lchan_prim_drop(lchan);
|
|
return -EINVAL;
|
|
}
|
|
if (msgb_l2len(lchan->prim) != l2_len) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR, "Primitive has odd length %u "
|
|
"(expected %zu for TCH or %u for FACCH), so dropping...\n",
|
|
msgb_l2len(lchan->prim), l2_len, GSM_MACBLOCK_LEN);
|
|
l1sched_lchan_prim_drop(lchan);
|
|
return -EINVAL;
|
|
}
|
|
rc = gsm0503_tch_hr_encode(buffer, msgb_l2(lchan->prim), l2_len);
|
|
}
|
|
|
|
if (rc) {
|
|
LOGP_LCHAND(lchan, LOGL_ERROR, "Failed to encode L2 payload (len=%u): %s\n",
|
|
msgb_l2len(lchan->prim), msgb_hexdump_l2(lchan->prim));
|
|
free_bad_msg:
|
|
l1sched_lchan_prim_drop(lchan);
|
|
return -EINVAL;
|
|
}
|
|
|
|
send_burst:
|
|
/* Determine which burst should be sent */
|
|
offset = buffer + br->bid * 116;
|
|
|
|
/* Update mask */
|
|
*mask |= (1 << br->bid);
|
|
|
|
/* Choose proper TSC */
|
|
tsc = l1sched_nb_training_bits[lchan->tsc];
|
|
|
|
/* Compose a new burst */
|
|
memset(br->burst, 0, 3); /* TB */
|
|
memcpy(br->burst + 3, offset, 58); /* Payload 1/2 */
|
|
memcpy(br->burst + 61, tsc, 26); /* TSC */
|
|
memcpy(br->burst + 87, offset + 58, 58); /* Payload 2/2 */
|
|
memset(br->burst + 145, 0, 3); /* TB */
|
|
br->burst_len = GSM_NBITS_NB_GMSK_BURST;
|
|
|
|
LOGP_LCHAND(lchan, LOGL_DEBUG, "Scheduled fn=%u burst=%u\n", br->fn, br->bid);
|
|
|
|
/* In case of a FACCH/H frame, one block less */
|
|
if (lchan->ul_facch_blocks)
|
|
lchan->ul_facch_blocks--;
|
|
|
|
if ((*mask & 0x0f) == 0x0f) {
|
|
/* Confirm data / traffic sending (pass ownership of the prim) */
|
|
if (!lchan->ul_facch_blocks)
|
|
l1sched_lchan_emit_data_cnf(lchan, br->fn);
|
|
else /* do not confirm dropped prims */
|
|
l1sched_lchan_prim_drop(lchan);
|
|
}
|
|
|
|
return 0;
|
|
}
|