Pablo Neira Ayuso | 0ba77d5 | 2011-06-05 18:32:44 +0200 | [diff] [blame] | 1 | #ifndef _SUBCH_DEMUX_H |
| 2 | #define _SUBCH_DEMUX_H |
| 3 | /* A E1 sub-channel (de)multiplexer with TRAU frame sync */ |
| 4 | |
| 5 | /* (C) 2009 by Harald Welte <laforge@gnumonks.org> |
| 6 | * All Rights Reserved |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU Affero General Public License as published by |
| 10 | * the Free Software Foundation; either version 3 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU Affero General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Affero General Public License |
| 19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | * |
| 21 | */ |
| 22 | |
| 23 | #include <stdint.h> |
| 24 | #include <osmocom/core/linuxlist.h> |
| 25 | |
| 26 | #define NR_SUBCH 4 |
| 27 | #define TRAU_FRAME_SIZE 40 |
| 28 | #define TRAU_FRAME_BITS (TRAU_FRAME_SIZE*8) |
| 29 | |
| 30 | /***********************************************************************/ |
| 31 | /* DEMULTIPLEXER */ |
| 32 | /***********************************************************************/ |
| 33 | |
| 34 | struct demux_subch { |
| 35 | uint8_t out_bitbuf[TRAU_FRAME_BITS]; |
| 36 | uint16_t out_idx; /* next bit to be written in out_bitbuf */ |
| 37 | /* number of consecutive zeros that we have received (for sync) */ |
| 38 | unsigned int consecutive_zeros; |
| 39 | /* are we in TRAU frame sync or not? */ |
| 40 | unsigned int in_sync; |
| 41 | }; |
| 42 | |
| 43 | struct subch_demux { |
| 44 | /* bitmask of currently active subchannels */ |
| 45 | uint8_t chan_activ; |
| 46 | /* one demux_subch struct for every subchannel */ |
| 47 | struct demux_subch subch[NR_SUBCH]; |
| 48 | /* callback to be called once we have received a complete |
| 49 | * frame on a given subchannel */ |
| 50 | int (*out_cb)(struct subch_demux *dmx, int ch, uint8_t *data, int len, |
| 51 | void *); |
| 52 | /* user-provided data, transparently passed to out_cb() */ |
| 53 | void *data; |
| 54 | }; |
| 55 | |
| 56 | /* initialize one demultiplexer instance */ |
| 57 | int subch_demux_init(struct subch_demux *dmx); |
| 58 | |
| 59 | /* feed 'len' number of muxed bytes into the demultiplexer */ |
| 60 | int subch_demux_in(struct subch_demux *dmx, uint8_t *data, int len); |
| 61 | |
| 62 | /* activate decoding/processing for one subchannel */ |
| 63 | int subch_demux_activate(struct subch_demux *dmx, int subch); |
| 64 | |
| 65 | /* deactivate decoding/processing for one subchannel */ |
| 66 | int subch_demux_deactivate(struct subch_demux *dmx, int subch); |
| 67 | |
| 68 | /***********************************************************************/ |
| 69 | /* MULTIPLEXER */ |
| 70 | /***********************************************************************/ |
| 71 | |
| 72 | /* one element in the tx_queue of a muxer sub-channel */ |
| 73 | struct subch_txq_entry { |
| 74 | struct llist_head list; |
| 75 | |
| 76 | unsigned int bit_len; /* total number of bits in 'bits' */ |
| 77 | unsigned int next_bit; /* next bit to be transmitted */ |
| 78 | |
| 79 | uint8_t bits[0]; /* one bit per byte */ |
| 80 | }; |
| 81 | |
| 82 | struct mux_subch { |
| 83 | struct llist_head tx_queue; |
| 84 | }; |
| 85 | |
| 86 | /* structure representing one instance of the subchannel muxer */ |
| 87 | struct subch_mux { |
| 88 | struct mux_subch subch[NR_SUBCH]; |
| 89 | }; |
| 90 | |
| 91 | /* initialize a subchannel muxer instance */ |
| 92 | int subchan_mux_init(struct subch_mux *mx); |
| 93 | |
| 94 | /* request the output of 'len' multiplexed bytes */ |
| 95 | int subchan_mux_out(struct subch_mux *mx, uint8_t *data, int len); |
| 96 | |
| 97 | /* enqueue some data into one sub-channel of the muxer */ |
| 98 | int subchan_mux_enqueue(struct subch_mux *mx, int s_nr, const uint8_t *data, |
| 99 | int len); |
| 100 | |
| 101 | #endif /* _SUBCH_DEMUX_H */ |