1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 *  OSLEC - A line echo canceller.  This code is being developed
4 *          against and partially complies with G168. Using code from SpanDSP
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *         and David Rowe <david_at_rowetel_dot_com>
8 *
9 * Copyright (C) 2001 Steve Underwood and 2007-2008 David Rowe
10 *
11 * All rights reserved.
12 */
13
14#ifndef __OSLEC_H
15#define __OSLEC_H
16
17/* Mask bits for the adaption mode */
18#define ECHO_CAN_USE_ADAPTION	0x01
19#define ECHO_CAN_USE_NLP	0x02
20#define ECHO_CAN_USE_CNG	0x04
21#define ECHO_CAN_USE_CLIP	0x08
22#define ECHO_CAN_USE_TX_HPF	0x10
23#define ECHO_CAN_USE_RX_HPF	0x20
24#define ECHO_CAN_DISABLE	0x40
25
26/**
27 * oslec_state: G.168 echo canceller descriptor.
28 *
29 * This defines the working state for a line echo canceller.
30 */
31struct oslec_state;
32
33/**
34 * oslec_create - Create a voice echo canceller context.
35 * @len: The length of the canceller, in samples.
36 * @return: The new canceller context, or NULL if the canceller could not be
37 * created.
38 */
39struct oslec_state *oslec_create(int len, int adaption_mode);
40
41/**
42 * oslec_free - Free a voice echo canceller context.
43 * @ec: The echo canceller context.
44 */
45void oslec_free(struct oslec_state *ec);
46
47/**
48 * oslec_flush - Flush (reinitialise) a voice echo canceller context.
49 * @ec: The echo canceller context.
50 */
51void oslec_flush(struct oslec_state *ec);
52
53/**
54 * oslec_adaption_mode - set the adaption mode of a voice echo canceller context.
55 * @ec The echo canceller context.
56 * @adaption_mode: The mode.
57 */
58void oslec_adaption_mode(struct oslec_state *ec, int adaption_mode);
59
60void oslec_snapshot(struct oslec_state *ec);
61
62/**
63 * oslec_update: Process a sample through a voice echo canceller.
64 * @ec: The echo canceller context.
65 * @tx: The transmitted audio sample.
66 * @rx: The received audio sample.
67 *
68 * The return value is the clean (echo cancelled) received sample.
69 */
70int16_t oslec_update(struct oslec_state *ec, int16_t tx, int16_t rx);
71
72/**
73 * oslec_hpf_tx: Process to high pass filter the tx signal.
74 * @ec: The echo canceller context.
75 * @tx: The transmitted auio sample.
76 *
77 * The return value is the HP filtered transmit sample, send this to your D/A.
78 */
79int16_t oslec_hpf_tx(struct oslec_state *ec, int16_t tx);
80
81#endif /* __OSLEC_H */
82