528463de574eaf1fcbc7780461d0de5dbed01a12
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file alsa_write.c paraslash's alsa output plugin */
8
9 /*
10 * Based in parts on aplay.c from the alsa-utils-1.0.8 package,
11 * Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
12 * based on the vplay program by Michael Beck.
13 */
14
15 #include <regex.h>
16 #include <sys/types.h>
17 #include <alsa/asoundlib.h>
18 #include <sys/time.h>
19
20 #include "para.h"
21 #include "fd.h"
22 #include "string.h"
23 #include "list.h"
24 #include "sched.h"
25 #include "ggo.h"
26 #include "buffer_tree.h"
27 #include "write.h"
28 #include "write_common.h"
29 #include "alsa_write.cmdline.h"
30 #include "error.h"
31
32 /** Data specific to the alsa writer. */
33 struct private_alsa_write_data {
34 /** The alsa handle */
35 snd_pcm_t *handle;
36 /** Determined and set by alsa_init(). */
37 int bytes_per_frame;
38 /**
39 * The sample rate given by command line option or the decoder
40 * of the writer node group.
41 */
42 unsigned sample_rate;
43 snd_pcm_format_t sample_format;
44 /**
45 * The number of channels, given by command line option or the
46 * decoder of the writer node group.
47 */
48 unsigned channels;
49 struct timeval drain_barrier;
50 /* File descriptor for select(). */
51 int poll_fd;
52 };
53
54 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
55 {
56 switch (sf) {
57 case SF_S8: return SND_PCM_FORMAT_S8;
58 case SF_U8: return SND_PCM_FORMAT_U8;
59 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
60 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
61 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
62 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
63 default: return SND_PCM_FORMAT_S16_LE;
64 }
65 }
66
67 /* Install PCM software and hardware configuration. */
68 static int alsa_init(struct private_alsa_write_data *pad,
69 struct alsa_write_args_info *conf)
70 {
71 snd_pcm_hw_params_t *hwparams;
72 snd_pcm_sw_params_t *swparams;
73 snd_pcm_uframes_t start_threshold, stop_threshold;
74 snd_pcm_uframes_t buffer_size, period_size;
75 snd_output_t *output_log;
76 unsigned buffer_time;
77 int ret;
78 const char *msg;
79
80 PARA_INFO_LOG("opening %s\n", conf->device_arg);
81 msg = "unable to open pcm";
82 ret = snd_pcm_open(&pad->handle, conf->device_arg,
83 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
84 if (ret < 0)
85 goto fail;
86 snd_pcm_hw_params_alloca(&hwparams);
87 msg = "Broken alsa configuration";
88 ret = snd_pcm_hw_params_any(pad->handle, hwparams);
89 if (ret < 0)
90 goto fail;
91 msg = "access type not available";
92 ret = snd_pcm_hw_params_set_access(pad->handle, hwparams,
93 SND_PCM_ACCESS_RW_INTERLEAVED);
94 if (ret < 0)
95 goto fail;
96 msg = "sample format not available";
97 ret = snd_pcm_hw_params_set_format(pad->handle, hwparams,
98 pad->sample_format);
99 if (ret < 0)
100 goto fail;
101 msg = "channels count not available";
102 ret = snd_pcm_hw_params_set_channels(pad->handle, hwparams,
103 pad->channels);
104 if (ret < 0)
105 goto fail;
106 msg = "could not set sample rate";
107 ret = snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
108 &pad->sample_rate, NULL);
109 if (ret < 0)
110 goto fail;
111 msg = "unable to get buffer time";
112 ret = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time,
113 NULL);
114 if (ret < 0 || buffer_time == 0)
115 goto fail;
116 msg = "could not set buffer time";
117 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
118 &buffer_time, NULL);
119 if (ret < 0)
120 goto fail;
121 msg = "unable to install hw params";
122 ret = snd_pcm_hw_params(pad->handle, hwparams);
123 if (ret < 0)
124 goto fail;
125 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
126 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
127 msg = "period size equals buffer size";
128 if (period_size == buffer_size)
129 goto fail;
130
131 /* software parameter setup */
132 snd_pcm_sw_params_alloca(&swparams);
133 snd_pcm_sw_params_current(pad->handle, swparams);
134 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
135 if (buffer_size < 1)
136 start_threshold = 1;
137 else
138 start_threshold = PARA_MIN(buffer_size,
139 (snd_pcm_uframes_t)pad->sample_rate);
140 msg = "could not set start threshold";
141 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
142 start_threshold);
143 if (ret < 0)
144 goto fail;
145 stop_threshold = buffer_size;
146 msg = "could not set stop threshold";
147 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
148 stop_threshold);
149 if (ret < 0)
150 goto fail;
151 msg = "unable to install sw params";
152 ret = snd_pcm_sw_params(pad->handle, swparams);
153 if (ret < 0)
154 goto fail;
155 msg = "unable to determine bytes per frame";
156 ret = snd_pcm_format_physical_width(pad->sample_format);
157 if (ret <= 0)
158 goto fail;
159 pad->bytes_per_frame = ret * pad->channels / 8;
160 msg = "failed to set alsa handle to nonblock mode";
161 ret = snd_pcm_nonblock(pad->handle, 1);
162 if (ret < 0)
163 goto fail;
164 ret = snd_output_buffer_open(&output_log);
165 if (ret == 0) {
166 char *buf;
167 PARA_INFO_LOG("dumping alsa configuration\n");
168 snd_pcm_dump(pad->handle, output_log);
169 snd_output_buffer_string(output_log, &buf);
170 for (;;) {
171 char *p = strchr(buf, '\n');
172 if (!p) /* omit last output line, it's empty */
173 break;
174 *p = '\0';
175 PARA_INFO_LOG("%s\n", buf);
176 buf = p + 1;
177 }
178 snd_output_close(output_log);
179 }
180 return 1;
181 fail:
182 if (ret < 0)
183 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
184 else
185 PARA_ERROR_LOG("%s\n", msg);
186 return -E_ALSA;
187 }
188
189 static void alsa_write_pre_select(struct sched *s, struct task *t)
190 {
191 struct pollfd pfd;
192 struct writer_node *wn = container_of(t, struct writer_node, task);
193 struct private_alsa_write_data *pad = wn->private_data;
194 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
195
196 if (pad)
197 pad->poll_fd = -1;
198 if (ret == 0)
199 return;
200 if (!pad) {
201 sched_min_delay(s);
202 return;
203 }
204 if (ret < 0) {
205 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
206 return;
207 }
208 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
209 if (ret < 0) {
210 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
211 snd_strerror(-ret));
212 t->error = -E_ALSA;
213 return;
214 }
215 pad->poll_fd = pfd.fd;
216 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
217 }
218
219 static void alsa_close(struct writer_node *wn)
220 {
221 struct private_alsa_write_data *pad = wn->private_data;
222 PARA_INFO_LOG("closing writer node %p\n", wn);
223
224 if (!pad)
225 return;
226 /*
227 * It's OK to have a blocking operation here because we already made
228 * sure that the PCM output buffer is (nearly) empty.
229 */
230 snd_pcm_nonblock(pad->handle, 0);
231 snd_pcm_drain(pad->handle);
232 snd_pcm_close(pad->handle);
233 snd_config_update_free_global();
234 free(pad);
235 }
236
237 static void alsa_write_post_select(__a_unused struct sched *s,
238 struct task *t)
239 {
240 struct writer_node *wn = container_of(t, struct writer_node, task);
241 struct private_alsa_write_data *pad = wn->private_data;
242 struct btr_node *btrn = wn->btrn;
243 char *data;
244 size_t bytes;
245 snd_pcm_sframes_t frames;
246 int ret;
247
248 again:
249 t->error = 0;
250 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
251 if (ret == 0)
252 return;
253 btr_merge(btrn, wn->min_iqs);
254 bytes = btr_next_buffer(btrn, &data);
255 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
256 assert(btr_no_parent(btrn));
257 ret = -E_WRITE_COMMON_EOF;
258 if (!pad)
259 goto err;
260 /* wait until pending frames are played */
261 if (pad->drain_barrier.tv_sec == 0) {
262 PARA_DEBUG_LOG("waiting for device to drain\n");
263 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
264 &pad->drain_barrier);
265 return;
266 }
267 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
268 goto err;
269 return;
270 }
271 if (!pad) {
272 int32_t val;
273
274 if (bytes == 0) /* no data available */
275 return;
276 pad = para_calloc(sizeof(*pad));
277 get_btr_sample_rate(btrn, &val);
278 pad->sample_rate = val;
279 get_btr_channels(btrn, &val);
280 pad->channels = val;
281 get_btr_sample_format(btrn, &val);
282 pad->sample_format = get_alsa_pcm_format(val);
283
284 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
285 pad->sample_rate);
286 ret = alsa_init(pad, wn->conf);
287 if (ret < 0) {
288 free(pad);
289 goto err;
290 }
291 wn->private_data = pad;
292 wn->min_iqs = pad->bytes_per_frame;
293 goto again;
294 }
295 if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
296 return;
297 frames = bytes / pad->bytes_per_frame;
298 frames = snd_pcm_writei(pad->handle, data, frames);
299 if (frames == 0 || frames == -EAGAIN) {
300 /*
301 * The alsa poll fd was ready for IO but we failed to write to
302 * the alsa handle. This means another event is pending. We
303 * don't care about that but we have to dispatch the event in
304 * order to avoid a busy loop. So we simply read from the poll
305 * fd.
306 */
307 char buf[100];
308 if (read(pad->poll_fd, buf, 100))
309 do_nothing;
310 return;
311 }
312 if (frames > 0) {
313 btr_consume(btrn, frames * pad->bytes_per_frame);
314 goto again;
315 }
316 if (frames == -EPIPE) {
317 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
318 snd_pcm_prepare(pad->handle);
319 return;
320 }
321 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
322 ret = -E_ALSA;
323 err:
324 assert(ret < 0);
325 btr_remove_node(btrn);
326 t->error = ret;
327 }
328
329 __malloc static void *alsa_parse_config_or_die(const char *options)
330 {
331 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
332
333 /* exits on errors */
334 alsa_cmdline_parser_string(options, conf, "alsa_write");
335 return conf;
336 }
337
338 static void alsa_free_config(void *conf)
339 {
340 alsa_cmdline_parser_free(conf);
341 }
342
343 /**
344 * The init function of the alsa writer.
345 *
346 * \param w Pointer to the writer to initialize.
347 *
348 * \sa struct \ref writer.
349 */
350 void alsa_write_init(struct writer *w)
351 {
352 struct alsa_write_args_info dummy;
353
354 alsa_cmdline_parser_init(&dummy);
355 w->close = alsa_close;
356 w->pre_select = alsa_write_pre_select;
357 w->post_select = alsa_write_post_select;
358 w->parse_config_or_die = alsa_parse_config_or_die;
359 w->shutdown = NULL; /* nothing to do */
360 w->free_config = alsa_free_config;
361 w->help = (struct ggo_help) {
362 .short_help = alsa_write_args_info_help,
363 .detailed_help = alsa_write_args_info_detailed_help
364 };
365 alsa_cmdline_parser_free(&dummy);
366 }