Merge branch 't/old_gcc_fixes'
[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 /* buffer at most 500 milliseconds */
117 buffer_time = PARA_MIN(buffer_time, 500U * 1000U);
118 msg = "could not set buffer time";
119 ret = snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
120 &buffer_time, NULL);
121 if (ret < 0)
122 goto fail;
123 msg = "unable to install hw params";
124 ret = snd_pcm_hw_params(pad->handle, hwparams);
125 if (ret < 0)
126 goto fail;
127 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
128 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
129 msg = "period size equals buffer size";
130 if (period_size == buffer_size)
131 goto fail;
132
133 /* software parameter setup */
134 snd_pcm_sw_params_alloca(&swparams);
135 snd_pcm_sw_params_current(pad->handle, swparams);
136 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
137 if (buffer_size < 1)
138 start_threshold = 1;
139 else
140 start_threshold = PARA_MIN(buffer_size,
141 (snd_pcm_uframes_t)pad->sample_rate);
142 msg = "could not set start threshold";
143 ret = snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
144 start_threshold);
145 if (ret < 0)
146 goto fail;
147 stop_threshold = buffer_size;
148 msg = "could not set stop threshold";
149 ret = snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
150 stop_threshold);
151 if (ret < 0)
152 goto fail;
153 msg = "unable to install sw params";
154 ret = snd_pcm_sw_params(pad->handle, swparams);
155 if (ret < 0)
156 goto fail;
157 msg = "unable to determine bytes per frame";
158 ret = snd_pcm_format_physical_width(pad->sample_format);
159 if (ret <= 0)
160 goto fail;
161 pad->bytes_per_frame = ret * pad->channels / 8;
162 msg = "failed to set alsa handle to nonblock mode";
163 ret = snd_pcm_nonblock(pad->handle, 1);
164 if (ret < 0)
165 goto fail;
166 ret = snd_output_buffer_open(&output_log);
167 if (ret == 0) {
168 char *buf;
169 PARA_INFO_LOG("dumping alsa configuration\n");
170 snd_pcm_dump(pad->handle, output_log);
171 snd_output_buffer_string(output_log, &buf);
172 for (;;) {
173 char *p = strchr(buf, '\n');
174 if (!p) /* omit last output line, it's empty */
175 break;
176 *p = '\0';
177 PARA_INFO_LOG("%s\n", buf);
178 buf = p + 1;
179 }
180 snd_output_close(output_log);
181 }
182 return 1;
183 fail:
184 if (ret < 0)
185 PARA_ERROR_LOG("%s: %s\n", msg, snd_strerror(-ret));
186 else
187 PARA_ERROR_LOG("%s\n", msg);
188 return -E_ALSA;
189 }
190
191 static void alsa_write_pre_select(struct sched *s, struct task *t)
192 {
193 struct pollfd pfd;
194 struct writer_node *wn = container_of(t, struct writer_node, task);
195 struct private_alsa_write_data *pad = wn->private_data;
196 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
197
198 if (pad)
199 pad->poll_fd = -1;
200 if (ret == 0)
201 return;
202 if (!pad) {
203 sched_min_delay(s);
204 return;
205 }
206 if (ret < 0) {
207 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
208 return;
209 }
210 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
211 if (ret < 0) {
212 PARA_ERROR_LOG("could not get alsa poll fd: %s\n",
213 snd_strerror(-ret));
214 t->error = -E_ALSA;
215 return;
216 }
217 pad->poll_fd = pfd.fd;
218 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
219 }
220
221 static void alsa_close(struct writer_node *wn)
222 {
223 struct private_alsa_write_data *pad = wn->private_data;
224 PARA_INFO_LOG("closing writer node %p\n", wn);
225
226 if (!pad)
227 return;
228 /*
229 * It's OK to have a blocking operation here because we already made
230 * sure that the PCM output buffer is (nearly) empty.
231 */
232 snd_pcm_nonblock(pad->handle, 0);
233 snd_pcm_drain(pad->handle);
234 snd_pcm_close(pad->handle);
235 snd_config_update_free_global();
236 free(pad);
237 }
238
239 static void alsa_write_post_select(__a_unused struct sched *s,
240 struct task *t)
241 {
242 struct writer_node *wn = container_of(t, struct writer_node, task);
243 struct private_alsa_write_data *pad = wn->private_data;
244 struct btr_node *btrn = wn->btrn;
245 char *data;
246 size_t bytes;
247 snd_pcm_sframes_t frames;
248 int ret;
249
250 again:
251 t->error = 0;
252 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
253 if (ret == 0)
254 return;
255 btr_merge(btrn, wn->min_iqs);
256 bytes = btr_next_buffer(btrn, &data);
257 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
258 assert(btr_no_parent(btrn));
259 ret = -E_WRITE_COMMON_EOF;
260 if (!pad)
261 goto err;
262 /* wait until pending frames are played */
263 if (pad->drain_barrier.tv_sec == 0) {
264 PARA_DEBUG_LOG("waiting for device to drain\n");
265 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
266 &pad->drain_barrier);
267 return;
268 }
269 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
270 goto err;
271 return;
272 }
273 if (!pad) {
274 int32_t val;
275
276 if (bytes == 0) /* no data available */
277 return;
278 pad = para_calloc(sizeof(*pad));
279 get_btr_sample_rate(btrn, &val);
280 pad->sample_rate = val;
281 get_btr_channels(btrn, &val);
282 pad->channels = val;
283 get_btr_sample_format(btrn, &val);
284 pad->sample_format = get_alsa_pcm_format(val);
285
286 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
287 pad->sample_rate);
288 ret = alsa_init(pad, wn->conf);
289 if (ret < 0) {
290 free(pad);
291 goto err;
292 }
293 wn->private_data = pad;
294 wn->min_iqs = pad->bytes_per_frame;
295 goto again;
296 }
297 if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
298 return;
299 frames = bytes / pad->bytes_per_frame;
300 frames = snd_pcm_writei(pad->handle, data, frames);
301 if (frames == 0 || frames == -EAGAIN) {
302 /*
303 * The alsa poll fd was ready for IO but we failed to write to
304 * the alsa handle. This means another event is pending. We
305 * don't care about that but we have to dispatch the event in
306 * order to avoid a busy loop. So we simply read from the poll
307 * fd.
308 */
309 char buf[100];
310 if (read(pad->poll_fd, buf, 100))
311 do_nothing;
312 return;
313 }
314 if (frames > 0) {
315 btr_consume(btrn, frames * pad->bytes_per_frame);
316 goto again;
317 }
318 if (frames == -EPIPE) {
319 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
320 snd_pcm_prepare(pad->handle);
321 return;
322 }
323 PARA_ERROR_LOG("alsa write error: %s\n", snd_strerror(-frames));
324 ret = -E_ALSA;
325 err:
326 assert(ret < 0);
327 btr_remove_node(btrn);
328 t->error = ret;
329 }
330
331 __malloc static void *alsa_parse_config_or_die(const char *options)
332 {
333 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
334
335 /* exits on errors */
336 alsa_cmdline_parser_string(options, conf, "alsa_write");
337 return conf;
338 }
339
340 static void alsa_free_config(void *conf)
341 {
342 alsa_cmdline_parser_free(conf);
343 }
344
345 /**
346 * The init function of the alsa writer.
347 *
348 * \param w Pointer to the writer to initialize.
349 *
350 * \sa struct \ref writer.
351 */
352 void alsa_write_init(struct writer *w)
353 {
354 struct alsa_write_args_info dummy;
355
356 alsa_cmdline_parser_init(&dummy);
357 w->close = alsa_close;
358 w->pre_select = alsa_write_pre_select;
359 w->post_select = alsa_write_post_select;
360 w->parse_config_or_die = alsa_parse_config_or_die;
361 w->free_config = alsa_free_config;
362 w->help = (struct ggo_help) {
363 .short_help = alsa_write_args_info_help,
364 .detailed_help = alsa_write_args_info_detailed_help
365 };
366 alsa_cmdline_parser_free(&dummy);
367 }