mirror of https://gerrit.osmocom.org/libosmocore
117 lines
4.0 KiB
C
117 lines
4.0 KiB
C
/*! \file i460_mux.h
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* ITU-T I.460 sub-channel multiplexer + demultiplexer */
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/*
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* (C) 2020 by Harald Welte <laforge@gnumonks.org>
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*
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* SPDX-License-Identifier: GPL-2.0+
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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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#pragma once
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#include <stdint.h>
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#include <osmocom/core/bits.h>
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#include <osmocom/core/linuxlist.h>
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#include <osmocom/core/msgb.h>
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/* I.460 sub-slot rate */
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enum osmo_i460_rate {
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OSMO_I460_RATE_NONE, /* disabled */
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OSMO_I460_RATE_64k,
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OSMO_I460_RATE_32k,
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OSMO_I460_RATE_16k,
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OSMO_I460_RATE_8k,
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};
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struct osmo_i460_subchan;
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typedef void (*out_cb_bits_t)(struct osmo_i460_subchan *schan, void *user_data,
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const ubit_t *bits, unsigned int num_bits);
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typedef void (*out_cb_bytes_t)(struct osmo_i460_subchan *schan, void *user_data,
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const uint8_t *bytes, unsigned int num_bytes);
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struct osmo_i460_subchan_demux {
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/*! bit-buffer for output bits */
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uint8_t *out_bitbuf;
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/*! size of out_bitbuf in bytes */
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unsigned int out_bitbuf_size;
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/*! offset of next bit to be written in out_bitbuf */
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unsigned int out_idx;
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/*! callback to be called once we have received out_bitbuf_size bits */
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out_cb_bits_t out_cb_bits;
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out_cb_bytes_t out_cb_bytes;
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void *user_data;
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};
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typedef void (*in_cb_queue_empty_t)(struct osmo_i460_subchan *schan, void *user_data);
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struct osmo_i460_subchan_mux {
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/*! list of to-be-transmitted message buffers */
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struct llist_head tx_queue;
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in_cb_queue_empty_t in_cb_queue_empty;
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void *user_data;
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};
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struct osmo_i460_subchan {
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struct osmo_i460_timeslot *ts; /* back-pointer */
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enum osmo_i460_rate rate; /* 8/16/32/64k */
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uint8_t bit_offset; /* bit offset inside each byte of the B-channel */
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struct osmo_i460_subchan_demux demux;
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struct osmo_i460_subchan_mux mux;
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};
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struct osmo_i460_timeslot {
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struct osmo_i460_subchan schan[8];
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};
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/*! description of a sub-channel; passed by caller */
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struct osmo_i460_schan_desc {
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enum osmo_i460_rate rate;
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uint8_t bit_offset;
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struct {
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/* size (in bits) of the internal buffer; determines granularity */
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size_t num_bits;
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/*! call-back function called whenever we received num_bits */
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out_cb_bits_t out_cb_bits;
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/*! out_cb_bytes call-back function called whenever we received num_bits.
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* The user is usually expected to provide either out_cb_bits or out_cb_bytes. If only
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* out_cb_bits is provided, output data will always be provided as unpacked bits; if only
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* out_cb_bytes is provided, output data will always be provided as packet bits (bytes). If
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* both are provided, it is up to the I.460 multiplex to decide if it calls either of the two,
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* depending on what can be provided without extra conversion. */
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out_cb_bytes_t out_cb_bytes;
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/* opaque user data pointer to pass to out_cb */
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void *user_data;
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} demux;
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struct {
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/* call-back function whenever the muxer requires more input data from the sub-channels,
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* but has nothing enqueued yet. A typical function would then call osmo_i460_mux_enqueue() */
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in_cb_queue_empty_t in_cb_queue_empty;
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/* opaque user data pointer to pass to in_cb */
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void *user_data;
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} mux;
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};
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void osmo_i460_demux_in(struct osmo_i460_timeslot *ts, const uint8_t *data, size_t data_len);
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void osmo_i460_mux_enqueue(struct osmo_i460_subchan *schan, struct msgb *msg);
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int osmo_i460_mux_out(struct osmo_i460_timeslot *ts, uint8_t *out, size_t out_len);
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void osmo_i460_ts_init(struct osmo_i460_timeslot *ts);
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struct osmo_i460_subchan *
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osmo_i460_subchan_add(void *ctx, struct osmo_i460_timeslot *ts, const struct osmo_i460_schan_desc *chd);
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void osmo_i460_subchan_del(struct osmo_i460_subchan *schan);
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/*! @} */
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