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 int proxy_prepare(alsa_device_proxy * proxy, alsa_device_profile* profile,
43 struct pcm_config * config)
44 {
45 int ret = 0;
46
47 ALOGV("proxy_prepare(c:%d, d:%d)", profile->card, profile->device);
48
49 proxy->profile = profile;
50
51 #ifdef LOG_PCM_PARAMS
52 log_pcm_config(config, "proxy_setup()");
53 #endif
54
55 if (config->format != PCM_FORMAT_INVALID && profile_is_format_valid(profile, config->format)) {
56 proxy->alsa_config.format = config->format;
57 } else {
58 proxy->alsa_config.format = profile->default_config.format;
59 ALOGW("Invalid format %d - using default %d.",
60 config->format, profile->default_config.format);
61 // Indicate override when default format was not requested
62 if (config->format != PCM_FORMAT_INVALID) {
63 ret = -EINVAL;
64 }
65 }
66
67 if (config->rate != 0 && profile_is_sample_rate_valid(profile, config->rate)) {
68 proxy->alsa_config.rate = config->rate;
69 } else {
70 proxy->alsa_config.rate = profile->default_config.rate;
71 ALOGW("Invalid sample rate %u - using default %u.",
72 config->rate, profile->default_config.rate);
73 // Indicate override when default rate was not requested
74 if (config->rate != 0) {
75 ret = -EINVAL;
76 }
77 }
78
79 if (config->channels != 0 && profile_is_channel_count_valid(profile, config->channels)) {
80 proxy->alsa_config.channels = config->channels;
81 } else {
82 proxy->alsa_config.channels = profile_get_closest_channel_count(profile, config->channels);
83 ALOGW("Invalid channel count %u - using closest %u.",
84 config->channels, proxy->alsa_config.channels);
85 // Indicate override when default channel count was not requested
86 if (config->channels != 0) {
87 ret = -EINVAL;
88 }
89 }
90
91 proxy->alsa_config.period_count = profile->default_config.period_count;
92 proxy->alsa_config.period_size =
93 profile_get_period_size(proxy->profile, proxy->alsa_config.rate);
94
95 // Hack for USB accessory audio.
96 // Here we set the correct value for period_count if tinyalsa fails to get it from the
97 // f_audio_source driver.
98 if (proxy->alsa_config.period_count == 0) {
99 proxy->alsa_config.period_count = 4;
100 }
101
102 proxy->pcm = NULL;
103 // config format should be checked earlier against profile.
104 if (config->format >= 0 && (size_t)config->format < ARRAY_SIZE(format_byte_size_map)) {
105 proxy->frame_size = format_byte_size_map[config->format] * proxy->alsa_config.channels;
106 } else {
107 proxy->frame_size = 1;
108 }
109
110 // let's check to make sure we can ACTUALLY use the maximum rate (with the channel count)
111 // Note that profile->sample_rates is sorted highest to lowest, so the scan will get
112 // us the highest working rate
113 int max_rate_index = proxy_scan_rates(proxy, profile->sample_rates);
114 if (max_rate_index >= 0) {
115 if (proxy->alsa_config.rate > profile->sample_rates[max_rate_index]) {
116 ALOGW("Limiting samplnig rate from %u to %u.",
117 proxy->alsa_config.rate, profile->sample_rates[max_rate_index]);
118 proxy->alsa_config.rate = profile->sample_rates[max_rate_index];
119 ret = -EINVAL;
120 }
121 }
122 return ret;
123 }
124
proxy_open(alsa_device_proxy * proxy)125 int proxy_open(alsa_device_proxy * proxy)
126 {
127 alsa_device_profile* profile = proxy->profile;
128 ALOGV("proxy_open(card:%d device:%d %s)", profile->card, profile->device,
129 profile->direction == PCM_OUT ? "PCM_OUT" : "PCM_IN");
130
131 if (profile->card < 0 || profile->device < 0) {
132 return -EINVAL;
133 }
134
135 proxy->pcm = pcm_open(profile->card, profile->device,
136 profile->direction | PCM_MONOTONIC, &proxy->alsa_config);
137 if (proxy->pcm == NULL) {
138 return -ENOMEM;
139 }
140
141 if (!pcm_is_ready(proxy->pcm)) {
142 ALOGE(" proxy_open() pcm_is_ready() failed: %s", pcm_get_error(proxy->pcm));
143 #if defined(LOG_PCM_PARAMS)
144 log_pcm_config(&proxy->alsa_config, "config");
145 #endif
146 pcm_close(proxy->pcm);
147 proxy->pcm = NULL;
148 return -ENOMEM;
149 }
150
151 return 0;
152 }
153
proxy_close(alsa_device_proxy * proxy)154 void proxy_close(alsa_device_proxy * proxy)
155 {
156 ALOGV("proxy_close() [pcm:%p]", proxy->pcm);
157
158 if (proxy->pcm != NULL) {
159 pcm_close(proxy->pcm);
160 proxy->pcm = NULL;
161 }
162 }
163
164 /*
165 * Sample Rate
166 */
proxy_get_sample_rate(const alsa_device_proxy * proxy)167 unsigned proxy_get_sample_rate(const alsa_device_proxy * proxy)
168 {
169 return proxy->alsa_config.rate;
170 }
171
172 /*
173 * Format
174 */
proxy_get_format(const alsa_device_proxy * proxy)175 enum pcm_format proxy_get_format(const alsa_device_proxy * proxy)
176 {
177 return proxy->alsa_config.format;
178 }
179
180 /*
181 * Channel Count
182 */
proxy_get_channel_count(const alsa_device_proxy * proxy)183 unsigned proxy_get_channel_count(const alsa_device_proxy * proxy)
184 {
185 return proxy->alsa_config.channels;
186 }
187
188 /*
189 * Other
190 */
proxy_get_period_size(const alsa_device_proxy * proxy)191 unsigned int proxy_get_period_size(const alsa_device_proxy * proxy)
192 {
193 return proxy->alsa_config.period_size;
194 }
195
proxy_get_period_count(const alsa_device_proxy * proxy)196 unsigned int proxy_get_period_count(const alsa_device_proxy * proxy)
197 {
198 return proxy->alsa_config.period_count;
199 }
200
proxy_get_latency(const alsa_device_proxy * proxy)201 unsigned proxy_get_latency(const alsa_device_proxy * proxy)
202 {
203 return (proxy_get_period_size(proxy) * proxy_get_period_count(proxy) * 1000)
204 / proxy_get_sample_rate(proxy);
205 }
206
proxy_get_presentation_position(const alsa_device_proxy * proxy,uint64_t * frames,struct timespec * timestamp)207 int proxy_get_presentation_position(const alsa_device_proxy * proxy,
208 uint64_t *frames, struct timespec *timestamp)
209 {
210 int ret = -EPERM; // -1
211 unsigned int avail;
212 if (proxy->pcm != NULL
213 && pcm_get_htimestamp(proxy->pcm, &avail, timestamp) == 0) {
214 const size_t kernel_buffer_size =
215 proxy->alsa_config.period_size * proxy->alsa_config.period_count;
216 if (avail > kernel_buffer_size) {
217 ALOGE("available frames(%u) > buffer size(%zu)", avail, kernel_buffer_size);
218 } else {
219 int64_t signed_frames = proxy->transferred - kernel_buffer_size + avail;
220 // It is possible to compensate for additional driver and device delay
221 // by changing signed_frames. Example:
222 // signed_frames -= 20 /* ms */ * proxy->alsa_config.rate / 1000;
223 if (signed_frames >= 0) {
224 *frames = signed_frames;
225 ret = 0;
226 }
227 }
228 }
229 return ret;
230 }
231
232 /*
233 * I/O
234 */
proxy_write(alsa_device_proxy * proxy,const void * data,unsigned int count)235 int proxy_write(alsa_device_proxy * proxy, const void *data, unsigned int count)
236 {
237 int ret = pcm_write(proxy->pcm, data, count);
238 if (ret == 0) {
239 proxy->transferred += count / proxy->frame_size;
240 }
241 return ret;
242 }
243
proxy_read(const alsa_device_proxy * proxy,void * data,unsigned int count)244 int proxy_read(const alsa_device_proxy * proxy, void *data, unsigned int count)
245 {
246 return pcm_read(proxy->pcm, data, count);
247 }
248
249 /*
250 * Debugging
251 */
proxy_dump(const alsa_device_proxy * proxy,int fd)252 void proxy_dump(const alsa_device_proxy* proxy, int fd)
253 {
254 if (proxy != NULL) {
255 dprintf(fd, " channels: %d\n", proxy->alsa_config.channels);
256 dprintf(fd, " rate: %d\n", proxy->alsa_config.rate);
257 dprintf(fd, " period_size: %d\n", proxy->alsa_config.period_size);
258 dprintf(fd, " period_count: %d\n", proxy->alsa_config.period_count);
259 dprintf(fd, " format: %d\n", proxy->alsa_config.format);
260 }
261 }
262
proxy_scan_rates(alsa_device_proxy * proxy,unsigned sample_rates[])263 int proxy_scan_rates(alsa_device_proxy * proxy, unsigned sample_rates[]) {
264 alsa_device_profile* profile = proxy->profile;
265 if (profile->card < 0 || profile->device < 0) {
266 return -EINVAL;
267 }
268
269 struct pcm_config alsa_config;
270 memcpy(&alsa_config, &proxy->alsa_config, sizeof(alsa_config));
271
272 struct pcm * alsa_pcm;
273 int rate_index = 0;
274 while (sample_rates[rate_index] != 0) {
275 alsa_config.rate = sample_rates[rate_index];
276 alsa_pcm = pcm_open(profile->card, profile->device,
277 profile->direction | PCM_MONOTONIC, &alsa_config);
278 if (alsa_pcm != NULL) {
279 if (pcm_is_ready(alsa_pcm)) {
280 pcm_close(alsa_pcm);
281 return rate_index;
282 }
283
284 pcm_close(alsa_pcm);
285 }
286
287 rate_index++;
288 }
289
290 return -EINVAL;
291 }
292