1/*
2 *  PCM DRM helpers
3 *
4 *   This program is free software; you can redistribute it and/or modify
5 *   it under the terms of the GNU General Public License version 2 as
6 *   published by the Free Software Foundation.
7 */
8#include <linux/export.h>
9#include <linux/types.h>
10#include <sound/asoundef.h>
11#include <sound/pcm.h>
12#include <sound/pcm_iec958.h>
13
14/**
15 * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
16 * @runtime: pcm runtime structure with ->rate filled in
17 * @cs: channel status buffer, at least four bytes
18 * @len: length of channel status buffer
19 *
20 * Create the consumer format channel status data in @cs of maximum size
21 * @len corresponding to the parameters of the PCM runtime @runtime.
22 *
23 * Drivers may wish to tweak the contents of the buffer after creation.
24 *
25 * Returns: length of buffer, or negative error code if something failed.
26 */
27int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
28	size_t len)
29{
30	unsigned int fs, ws;
31
32	if (len < 4)
33		return -EINVAL;
34
35	switch (runtime->rate) {
36	case 32000:
37		fs = IEC958_AES3_CON_FS_32000;
38		break;
39	case 44100:
40		fs = IEC958_AES3_CON_FS_44100;
41		break;
42	case 48000:
43		fs = IEC958_AES3_CON_FS_48000;
44		break;
45	case 88200:
46		fs = IEC958_AES3_CON_FS_88200;
47		break;
48	case 96000:
49		fs = IEC958_AES3_CON_FS_96000;
50		break;
51	case 176400:
52		fs = IEC958_AES3_CON_FS_176400;
53		break;
54	case 192000:
55		fs = IEC958_AES3_CON_FS_192000;
56		break;
57	default:
58		return -EINVAL;
59	}
60
61	if (len > 4) {
62		switch (snd_pcm_format_width(runtime->format)) {
63		case 16:
64			ws = IEC958_AES4_CON_WORDLEN_20_16;
65			break;
66		case 18:
67			ws = IEC958_AES4_CON_WORDLEN_22_18;
68			break;
69		case 20:
70			ws = IEC958_AES4_CON_WORDLEN_20_16 |
71			     IEC958_AES4_CON_MAX_WORDLEN_24;
72			break;
73		case 24:
74			ws = IEC958_AES4_CON_WORDLEN_24_20 |
75			     IEC958_AES4_CON_MAX_WORDLEN_24;
76			break;
77
78		default:
79			return -EINVAL;
80		}
81	}
82
83	memset(cs, 0, len);
84
85	cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
86	cs[1] = IEC958_AES1_CON_GENERAL;
87	cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
88	cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
89
90	if (len > 4)
91		cs[4] = ws;
92
93	return len;
94}
95EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
96