1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "alsa_device_proxy"
18 /*#define LOG_NDEBUG 0*/
19 /*#define LOG_PCM_PARAMS 0*/
20
21 #include <log/log.h>
22
23 #include <errno.h>
24
25 #include "include/alsa_device_proxy.h"
26
27 #include "include/alsa_logging.h"
28
29 #define DEFAULT_PERIOD_SIZE 1024
30 #define DEFAULT_PERIOD_COUNT 2
31
32 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
33
34 static const unsigned format_byte_size_map[] = {
35 2, /* PCM_FORMAT_S16_LE */
36 4, /* PCM_FORMAT_S32_LE */
37 1, /* PCM_FORMAT_S8 */
38 4, /* PCM_FORMAT_S24_LE */
39 3, /* PCM_FORMAT_S24_3LE */
40 };
41
proxy_prepare(alsa_device_proxy * proxy,alsa_device_profile * profile,struct pcm_config * config)42 void proxy_prepare(alsa_device_proxy * proxy, alsa_device_profile* profile,
43 struct pcm_config * config)
44 {
45 ALOGV("proxy_prepare(c:%d, d:%d)", profile->card, profile->device);
46
47 proxy->profile = profile;
48
49 #ifdef LOG_PCM_PARAMS
50 log_pcm_config(config, "proxy_setup()");
51 #endif
52
53 if (config->format != PCM_FORMAT_INVALID && profile_is_format_valid(profile, config->format)) {
54 proxy->alsa_config.format = config->format;
55 } else {
56 ALOGW("Invalid format %d - using default %d.",
57 config->format, profile->default_config.format);
58 proxy->alsa_config.format = profile->default_config.format;
59 }
60
61 if (config->rate != 0 && profile_is_sample_rate_valid(profile, config->rate)) {
62 proxy->alsa_config.rate = config->rate;
63 } else {
64 ALOGW("Invalid sample rate %u - using default %u.",
65 config->rate, profile->default_config.rate);
66 proxy->alsa_config.rate = profile->default_config.rate;
67 }
68
69 if (config->channels != 0 && profile_is_channel_count_valid(profile, config->channels)) {
70 proxy->alsa_config.channels = config->channels;
71 } else {
72 ALOGW("Invalid channel count %u - using default %u.",
73 config->channels, profile->default_config.channels);
74 proxy->alsa_config.channels = profile->default_config.channels;
75
76 }
77
78 proxy->alsa_config.period_count = profile->default_config.period_count;
79 proxy->alsa_config.period_size =
80 profile_get_period_size(proxy->profile, proxy->alsa_config.rate);
81
82 // Hack for USB accessory audio.
83 // Here we set the correct value for period_count if tinyalsa fails to get it from the
84 // f_audio_source driver.
85 if (proxy->alsa_config.period_count == 0) {
86 proxy->alsa_config.period_count = 4;
87 }
88
89 proxy->pcm = NULL;
90 // config format should be checked earlier against profile.
91 if (config->format >= 0 && (size_t)config->format < ARRAY_SIZE(format_byte_size_map)) {
92 proxy->frame_size = format_byte_size_map[config->format] * proxy->alsa_config.channels;
93 } else {
94 proxy->frame_size = 1;
95 }
96 }
97
proxy_open(alsa_device_proxy * proxy)98 int proxy_open(alsa_device_proxy * proxy)
99 {
100 alsa_device_profile* profile = proxy->profile;
101 ALOGV("proxy_open(card:%d device:%d %s)", profile->card, profile->device,
102 profile->direction == PCM_OUT ? "PCM_OUT" : "PCM_IN");
103
104 if (profile->card < 0 || profile->device < 0) {
105 return -EINVAL;
106 }
107
108 proxy->pcm = pcm_open(profile->card, profile->device,
109 profile->direction | PCM_MONOTONIC, &proxy->alsa_config);
110 if (proxy->pcm == NULL) {
111 return -ENOMEM;
112 }
113
114 if (!pcm_is_ready(proxy->pcm)) {
115 ALOGE(" proxy_open() pcm_open() failed: %s", pcm_get_error(proxy->pcm));
116 #if defined(LOG_PCM_PARAMS)
117 log_pcm_config(&proxy->alsa_config, "config");
118 #endif
119 pcm_close(proxy->pcm);
120 proxy->pcm = NULL;
121 return -ENOMEM;
122 }
123
124 return 0;
125 }
126
proxy_close(alsa_device_proxy * proxy)127 void proxy_close(alsa_device_proxy * proxy)
128 {
129 ALOGV("proxy_close() [pcm:%p]", proxy->pcm);
130
131 if (proxy->pcm != NULL) {
132 pcm_close(proxy->pcm);
133 proxy->pcm = NULL;
134 }
135 }
136
137 /*
138 * Sample Rate
139 */
proxy_get_sample_rate(const alsa_device_proxy * proxy)140 unsigned proxy_get_sample_rate(const alsa_device_proxy * proxy)
141 {
142 return proxy->alsa_config.rate;
143 }
144
145 /*
146 * Format
147 */
proxy_get_format(const alsa_device_proxy * proxy)148 enum pcm_format proxy_get_format(const alsa_device_proxy * proxy)
149 {
150 return proxy->alsa_config.format;
151 }
152
153 /*
154 * Channel Count
155 */
proxy_get_channel_count(const alsa_device_proxy * proxy)156 unsigned proxy_get_channel_count(const alsa_device_proxy * proxy)
157 {
158 return proxy->alsa_config.channels;
159 }
160
161 /*
162 * Other
163 */
proxy_get_period_size(const alsa_device_proxy * proxy)164 unsigned int proxy_get_period_size(const alsa_device_proxy * proxy)
165 {
166 return proxy->alsa_config.period_size;
167 }
168
proxy_get_period_count(const alsa_device_proxy * proxy)169 unsigned int proxy_get_period_count(const alsa_device_proxy * proxy)
170 {
171 return proxy->alsa_config.period_count;
172 }
173
proxy_get_latency(const alsa_device_proxy * proxy)174 unsigned proxy_get_latency(const alsa_device_proxy * proxy)
175 {
176 return (proxy_get_period_size(proxy) * proxy_get_period_count(proxy) * 1000)
177 / proxy_get_sample_rate(proxy);
178 }
179
proxy_get_presentation_position(const alsa_device_proxy * proxy,uint64_t * frames,struct timespec * timestamp)180 int proxy_get_presentation_position(const alsa_device_proxy * proxy,
181 uint64_t *frames, struct timespec *timestamp)
182 {
183 int ret = -EPERM; // -1
184 unsigned int avail;
185 if (proxy->pcm != NULL
186 && pcm_get_htimestamp(proxy->pcm, &avail, timestamp) == 0) {
187 const size_t kernel_buffer_size =
188 proxy->alsa_config.period_size * proxy->alsa_config.period_count;
189 if (avail > kernel_buffer_size) {
190 ALOGE("available frames(%u) > buffer size(%zu)", avail, kernel_buffer_size);
191 } else {
192 int64_t signed_frames = proxy->transferred - kernel_buffer_size + avail;
193 // It is possible to compensate for additional driver and device delay
194 // by changing signed_frames. Example:
195 // signed_frames -= 20 /* ms */ * proxy->alsa_config.rate / 1000;
196 if (signed_frames >= 0) {
197 *frames = signed_frames;
198 ret = 0;
199 }
200 }
201 }
202 return ret;
203 }
204
205 /*
206 * I/O
207 */
proxy_write(alsa_device_proxy * proxy,const void * data,unsigned int count)208 int proxy_write(alsa_device_proxy * proxy, const void *data, unsigned int count)
209 {
210 int ret = pcm_write(proxy->pcm, data, count);
211 if (ret == 0) {
212 proxy->transferred += count / proxy->frame_size;
213 }
214 return ret;
215 }
216
proxy_read(const alsa_device_proxy * proxy,void * data,unsigned int count)217 int proxy_read(const alsa_device_proxy * proxy, void *data, unsigned int count)
218 {
219 return pcm_read(proxy->pcm, data, count);
220 }
221