i460_mux.h

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/*
 * (C) 2020 by Harald Welte <laforge@gnumonks.org>
 *
 * SPDX-License-Identifier: GPL-2.0+
 *
 *  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.
 */
 
#pragma once
#include <stdint.h>
#include <osmocom/core/bits.h>
#include <osmocom/core/linuxlist.h>
#include <osmocom/core/msgb.h>
 
#define OSMO_I460_NUM_SUBCHAN 8
 
/* I.460 sub-slot rate */
enum osmo_i460_rate {
        OSMO_I460_RATE_NONE,            /* disabled */
        OSMO_I460_RATE_64k,
        OSMO_I460_RATE_32k,
        OSMO_I460_RATE_16k,
        OSMO_I460_RATE_8k,
};
 
struct osmo_i460_subchan;
 
typedef void (*out_cb_bits_t)(struct osmo_i460_subchan *schan, void *user_data,
                              const ubit_t *bits, unsigned int num_bits);
typedef void (*out_cb_bytes_t)(struct osmo_i460_subchan *schan, void *user_data,
                               const uint8_t *bytes, unsigned int num_bytes);
 
struct osmo_i460_subchan_demux {
        uint8_t *out_bitbuf;
        unsigned int out_bitbuf_size;
        unsigned int out_idx;
        out_cb_bits_t out_cb_bits;
        out_cb_bytes_t out_cb_bytes;
        void *user_data;
};
 
typedef void (*in_cb_queue_empty_t)(struct osmo_i460_subchan *schan, void *user_data);
 
struct osmo_i460_subchan_mux {
        struct llist_head tx_queue;
        in_cb_queue_empty_t in_cb_queue_empty;
        void *user_data;
};
 
struct osmo_i460_subchan {
        struct osmo_i460_timeslot *ts;  /* back-pointer */
        enum osmo_i460_rate rate;               /* 8/16/32/64k */
        uint8_t bit_offset;             /* bit offset inside each byte of the B-channel */
        struct osmo_i460_subchan_demux demux;
        struct osmo_i460_subchan_mux mux;
};
 
struct osmo_i460_timeslot {
        struct osmo_i460_subchan schan[OSMO_I460_NUM_SUBCHAN];
};
 
struct osmo_i460_schan_desc {
        enum osmo_i460_rate rate;
        uint8_t bit_offset;
        struct {
                /* size (in bits) of the internal buffer; determines granularity */
                size_t num_bits;
                out_cb_bits_t out_cb_bits;
                out_cb_bytes_t out_cb_bytes;
                /* opaque user data pointer to pass to out_cb */
                void *user_data;
        } demux;
 
        struct {
                /* call-back function whenever the muxer requires more input data from the sub-channels,
                 * but has nothing enqueued yet. A typical function would then call osmo_i460_mux_enqueue() */
                in_cb_queue_empty_t in_cb_queue_empty;
                /* opaque user data pointer to pass to in_cb */
                void *user_data;
        } mux;
};
 
void osmo_i460_demux_in(struct osmo_i460_timeslot *ts, const uint8_t *data, size_t data_len);
 
void osmo_i460_mux_enqueue(struct osmo_i460_subchan *schan, struct msgb *msg);
int osmo_i460_mux_out(struct osmo_i460_timeslot *ts, uint8_t *out, size_t out_len);
 
void osmo_i460_ts_init(struct osmo_i460_timeslot *ts);
 
struct osmo_i460_subchan *
osmo_i460_subchan_add(void *ctx, struct osmo_i460_timeslot *ts, const struct osmo_i460_schan_desc *chd);
 
void osmo_i460_subchan_del(struct osmo_i460_subchan *schan);
 
int osmo_i460_subchan_count(struct osmo_i460_timeslot *ts);