1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * PCM DRM helpers
4 */
5 #include <linux/export.h>
6 #include <linux/types.h>
7 #include <sound/asoundef.h>
8 #include <sound/pcm.h>
9 #include <sound/pcm_params.h>
10 #include <sound/pcm_iec958.h>
11
12 static int create_iec958_consumer(uint rate, uint sample_width,
13 u8 *cs, size_t len)
14 {
15 unsigned int fs, ws;
16
17 if (len < 4)
18 return -EINVAL;
19
20 switch (rate) {
21 case 32000:
22 fs = IEC958_AES3_CON_FS_32000;
23 break;
24 case 44100:
25 fs = IEC958_AES3_CON_FS_44100;
26 break;
27 case 48000:
28 fs = IEC958_AES3_CON_FS_48000;
29 break;
30 case 88200:
31 fs = IEC958_AES3_CON_FS_88200;
32 break;
33 case 96000:
34 fs = IEC958_AES3_CON_FS_96000;
35 break;
36 case 176400:
37 fs = IEC958_AES3_CON_FS_176400;
38 break;
39 case 192000:
40 fs = IEC958_AES3_CON_FS_192000;
41 break;
42 default:
43 return -EINVAL;
44 }
45
46 if (len > 4) {
47 switch (sample_width) {
48 case 16:
49 ws = IEC958_AES4_CON_WORDLEN_20_16;
50 break;
51 case 18:
52 ws = IEC958_AES4_CON_WORDLEN_22_18;
53 break;
54 case 20:
55 ws = IEC958_AES4_CON_WORDLEN_20_16 |
56 IEC958_AES4_CON_MAX_WORDLEN_24;
57 break;
58 case 24:
59 case 32: /* Assume 24-bit width for 32-bit samples. */
60 ws = IEC958_AES4_CON_WORDLEN_24_20 |
61 IEC958_AES4_CON_MAX_WORDLEN_24;
62 break;
63
64 default:
65 return -EINVAL;
66 }
67 }
68
69 memset(cs, 0, len);
70
71 cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
72 cs[1] = IEC958_AES1_CON_GENERAL;
73 cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
74 cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | fs;
75
76 if (len > 4)
77 cs[4] = ws;
78
79 return len;
80 }
81
82 /**
83 * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
84 * @runtime: pcm runtime structure with ->rate filled in
85 * @cs: channel status buffer, at least four bytes
86 * @len: length of channel status buffer
87 *
88 * Create the consumer format channel status data in @cs of maximum size
89 * @len corresponding to the parameters of the PCM runtime @runtime.
90 *
91 * Drivers may wish to tweak the contents of the buffer after creation.
92 *
93 * Returns: length of buffer, or negative error code if something failed.
94 */
95 int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
96 size_t len)
97 {
98 return create_iec958_consumer(runtime->rate,
99 snd_pcm_format_width(runtime->format),
100 cs, len);
101 }
102 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
103
104 /**
105 * snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
106 * @hw_params: the hw_params instance for extracting rate and sample format
107 * @cs: channel status buffer, at least four bytes
108 * @len: length of channel status buffer
109 *
110 * Create the consumer format channel status data in @cs of maximum size
111 * @len corresponding to the parameters of the PCM runtime @runtime.
112 *
113 * Drivers may wish to tweak the contents of the buffer after creation.
114 *
115 * Returns: length of buffer, or negative error code if something failed.
116 */
117 int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
118 u8 *cs, size_t len)
119 {
120 return create_iec958_consumer(params_rate(params), params_width(params),
121 cs, len);
122 }
123 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);