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 /**
13 * snd_pcm_create_iec958_consumer_default - create default consumer format IEC958 channel status
14 * @cs: channel status buffer, at least four bytes
15 * @len: length of channel status buffer
16 *
17 * Create the consumer format channel status data in @cs of maximum size
18 * @len. When relevant, the configuration-dependant bits will be set as
19 * unspecified.
20 *
21 * Drivers should then call einter snd_pcm_fill_iec958_consumer() or
22 * snd_pcm_fill_iec958_consumer_hw_params() to replace these unspecified
23 * bits by their actual values.
24 *
25 * Drivers may wish to tweak the contents of the buffer after creation.
26 *
27 * Returns: length of buffer, or negative error code if something failed.
28 */
snd_pcm_create_iec958_consumer_default(u8 * cs,size_t len)29 int snd_pcm_create_iec958_consumer_default(u8 *cs, size_t len)
30 {
31 if (len < 4)
32 return -EINVAL;
33
34 memset(cs, 0, len);
35
36 cs[0] = IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE;
37 cs[1] = IEC958_AES1_CON_GENERAL;
38 cs[2] = IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC;
39 cs[3] = IEC958_AES3_CON_CLOCK_1000PPM | IEC958_AES3_CON_FS_NOTID;
40
41 if (len > 4)
42 cs[4] = IEC958_AES4_CON_WORDLEN_NOTID;
43
44 return len;
45 }
46 EXPORT_SYMBOL_GPL(snd_pcm_create_iec958_consumer_default);
47
fill_iec958_consumer(uint rate,uint sample_width,u8 * cs,size_t len)48 static int fill_iec958_consumer(uint rate, uint sample_width,
49 u8 *cs, size_t len)
50 {
51 if (len < 4)
52 return -EINVAL;
53
54 if ((cs[3] & IEC958_AES3_CON_FS) == IEC958_AES3_CON_FS_NOTID) {
55 unsigned int fs;
56
57 switch (rate) {
58 case 32000:
59 fs = IEC958_AES3_CON_FS_32000;
60 break;
61 case 44100:
62 fs = IEC958_AES3_CON_FS_44100;
63 break;
64 case 48000:
65 fs = IEC958_AES3_CON_FS_48000;
66 break;
67 case 88200:
68 fs = IEC958_AES3_CON_FS_88200;
69 break;
70 case 96000:
71 fs = IEC958_AES3_CON_FS_96000;
72 break;
73 case 176400:
74 fs = IEC958_AES3_CON_FS_176400;
75 break;
76 case 192000:
77 fs = IEC958_AES3_CON_FS_192000;
78 break;
79 default:
80 return -EINVAL;
81 }
82
83 cs[3] &= ~IEC958_AES3_CON_FS;
84 cs[3] |= fs;
85 }
86
87 if (len > 4 &&
88 (cs[4] & IEC958_AES4_CON_WORDLEN) == IEC958_AES4_CON_WORDLEN_NOTID) {
89 unsigned int ws;
90
91 switch (sample_width) {
92 case 16:
93 ws = IEC958_AES4_CON_WORDLEN_20_16;
94 break;
95 case 18:
96 ws = IEC958_AES4_CON_WORDLEN_22_18;
97 break;
98 case 20:
99 ws = IEC958_AES4_CON_WORDLEN_20_16 |
100 IEC958_AES4_CON_MAX_WORDLEN_24;
101 break;
102 case 24:
103 case 32: /* Assume 24-bit width for 32-bit samples. */
104 ws = IEC958_AES4_CON_WORDLEN_24_20 |
105 IEC958_AES4_CON_MAX_WORDLEN_24;
106 break;
107
108 default:
109 return -EINVAL;
110 }
111
112 cs[4] &= ~IEC958_AES4_CON_WORDLEN;
113 cs[4] |= ws;
114 }
115
116 return len;
117 }
118
119 /**
120 * snd_pcm_fill_iec958_consumer - Fill consumer format IEC958 channel status
121 * @runtime: pcm runtime structure with ->rate filled in
122 * @cs: channel status buffer, at least four bytes
123 * @len: length of channel status buffer
124 *
125 * Fill the unspecified bits in an IEC958 status bits array using the
126 * parameters of the PCM runtime @runtime.
127 *
128 * Drivers may wish to tweak the contents of the buffer after its been
129 * filled.
130 *
131 * Returns: length of buffer, or negative error code if something failed.
132 */
snd_pcm_fill_iec958_consumer(struct snd_pcm_runtime * runtime,u8 * cs,size_t len)133 int snd_pcm_fill_iec958_consumer(struct snd_pcm_runtime *runtime,
134 u8 *cs, size_t len)
135 {
136 return fill_iec958_consumer(runtime->rate,
137 snd_pcm_format_width(runtime->format),
138 cs, len);
139 }
140 EXPORT_SYMBOL_GPL(snd_pcm_fill_iec958_consumer);
141
142 /**
143 * snd_pcm_fill_iec958_consumer_hw_params - Fill consumer format IEC958 channel status
144 * @params: the hw_params instance for extracting rate and sample format
145 * @cs: channel status buffer, at least four bytes
146 * @len: length of channel status buffer
147 *
148 * Fill the unspecified bits in an IEC958 status bits array using the
149 * parameters of the PCM hardware parameters @params.
150 *
151 * Drivers may wish to tweak the contents of the buffer after its been
152 * filled..
153 *
154 * Returns: length of buffer, or negative error code if something failed.
155 */
snd_pcm_fill_iec958_consumer_hw_params(struct snd_pcm_hw_params * params,u8 * cs,size_t len)156 int snd_pcm_fill_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
157 u8 *cs, size_t len)
158 {
159 return fill_iec958_consumer(params_rate(params), params_width(params), cs, len);
160 }
161 EXPORT_SYMBOL_GPL(snd_pcm_fill_iec958_consumer_hw_params);
162
163 /**
164 * snd_pcm_create_iec958_consumer - create consumer format IEC958 channel status
165 * @runtime: pcm runtime structure with ->rate filled in
166 * @cs: channel status buffer, at least four bytes
167 * @len: length of channel status buffer
168 *
169 * Create the consumer format channel status data in @cs of maximum size
170 * @len corresponding to the parameters of the PCM runtime @runtime.
171 *
172 * Drivers may wish to tweak the contents of the buffer after creation.
173 *
174 * Returns: length of buffer, or negative error code if something failed.
175 */
snd_pcm_create_iec958_consumer(struct snd_pcm_runtime * runtime,u8 * cs,size_t len)176 int snd_pcm_create_iec958_consumer(struct snd_pcm_runtime *runtime, u8 *cs,
177 size_t len)
178 {
179 int ret;
180
181 ret = snd_pcm_create_iec958_consumer_default(cs, len);
182 if (ret < 0)
183 return ret;
184
185 return snd_pcm_fill_iec958_consumer(runtime, cs, len);
186 }
187 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer);
188
189 /**
190 * snd_pcm_create_iec958_consumer_hw_params - create IEC958 channel status
191 * @params: the hw_params instance for extracting rate and sample format
192 * @cs: channel status buffer, at least four bytes
193 * @len: length of channel status buffer
194 *
195 * Create the consumer format channel status data in @cs of maximum size
196 * @len corresponding to the parameters of the PCM runtime @runtime.
197 *
198 * Drivers may wish to tweak the contents of the buffer after creation.
199 *
200 * Returns: length of buffer, or negative error code if something failed.
201 */
snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params * params,u8 * cs,size_t len)202 int snd_pcm_create_iec958_consumer_hw_params(struct snd_pcm_hw_params *params,
203 u8 *cs, size_t len)
204 {
205 int ret;
206
207 ret = snd_pcm_create_iec958_consumer_default(cs, len);
208 if (ret < 0)
209 return ret;
210
211 return fill_iec958_consumer(params_rate(params), params_width(params), cs, len);
212 }
213 EXPORT_SYMBOL(snd_pcm_create_iec958_consumer_hw_params);
214