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