alsa: Make two variables local to alsa_init().
[paraslash.git] / alsa_write.c
1 /*
2 * Copyright (C) 2005-2011 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 #include <stdbool.h>
20
21 #include "para.h"
22 #include "fd.h"
23 #include "string.h"
24 #include "list.h"
25 #include "sched.h"
26 #include "ggo.h"
27 #include "buffer_tree.h"
28 #include "write.h"
29 #include "write_common.h"
30 #include "alsa_write.cmdline.h"
31 #include "error.h"
32
33 /** Data specific to the alsa writer. */
34 struct private_alsa_write_data {
35 /** The alsa handle */
36 snd_pcm_t *handle;
37 /** Determined and set by alsa_init(). */
38 int bytes_per_frame;
39 /**
40 * The sample rate given by command line option or the decoder
41 * of the writer node group.
42 */
43 unsigned sample_rate;
44 snd_pcm_format_t sample_format;
45 /**
46 * The number of channels, given by command line option or the
47 * decoder of the writer node group.
48 */
49 unsigned channels;
50 struct timeval drain_barrier;
51 /* File descriptor for select(). */
52 int poll_fd;
53 };
54
55 static snd_pcm_format_t get_alsa_pcm_format(enum sample_format sf)
56 {
57 switch (sf) {
58 case SF_S8: return SND_PCM_FORMAT_S8;
59 case SF_U8: return SND_PCM_FORMAT_U8;
60 case SF_S16_LE: return SND_PCM_FORMAT_S16_LE;
61 case SF_S16_BE: return SND_PCM_FORMAT_S16_BE;
62 case SF_U16_LE: return SND_PCM_FORMAT_U16_LE;
63 case SF_U16_BE: return SND_PCM_FORMAT_U16_BE;
64 default: return SND_PCM_FORMAT_S16_LE;
65 }
66 }
67
68 /* Install PCM software and hardware configuration. */
69 static int alsa_init(struct private_alsa_write_data *pad,
70 struct alsa_write_args_info *conf)
71 {
72 snd_pcm_hw_params_t *hwparams;
73 snd_pcm_sw_params_t *swparams;
74 snd_pcm_uframes_t start_threshold, stop_threshold;
75 snd_pcm_uframes_t buffer_size, period_size;
76 snd_output_t *log;
77 unsigned buffer_time;
78 int err;
79
80 PARA_INFO_LOG("opening %s\n", conf->device_arg);
81 err = snd_pcm_open(&pad->handle, conf->device_arg,
82 SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
83 if (err < 0)
84 return -E_PCM_OPEN;
85
86 snd_pcm_hw_params_alloca(&hwparams);
87 snd_pcm_sw_params_alloca(&swparams);
88 if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
89 return -E_BROKEN_CONF;
90 if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
91 SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
92 return -E_ACCESS_TYPE;
93 if (snd_pcm_hw_params_set_format(pad->handle, hwparams,
94 pad->sample_format) < 0)
95 return -E_SAMPLE_FORMAT;
96 if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
97 pad->channels) < 0)
98 return -E_CHANNEL_COUNT;
99 if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
100 &pad->sample_rate, NULL) < 0)
101 return -E_SET_RATE;
102 err = snd_pcm_hw_params_get_buffer_time_max(hwparams,
103 &buffer_time, NULL);
104 if (err < 0 || buffer_time == 0)
105 return -E_GET_BUFFER_TIME;
106 if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
107 &buffer_time, NULL) < 0)
108 return -E_SET_BUFFER_TIME;
109 if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
110 return -E_HW_PARAMS;
111 snd_pcm_hw_params_get_period_size(hwparams, &period_size, NULL);
112 snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
113 if (period_size == buffer_size)
114 return -E_BAD_PERIOD;
115 /* software parameter setup */
116 snd_pcm_sw_params_current(pad->handle, swparams);
117 snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
118 if (buffer_size < 1)
119 start_threshold = 1;
120 else
121 start_threshold = PARA_MIN(buffer_size,
122 (snd_pcm_uframes_t)pad->sample_rate);
123 if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
124 start_threshold) < 0)
125 return -E_START_THRESHOLD;
126 stop_threshold = buffer_size;
127 if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
128 stop_threshold) < 0)
129 return -E_STOP_THRESHOLD;
130 if (snd_pcm_sw_params(pad->handle, swparams) < 0)
131 PARA_WARNING_LOG("unable to install sw params\n");
132 pad->bytes_per_frame = snd_pcm_format_physical_width(pad->sample_format)
133 * pad->channels / 8;
134 if (pad->bytes_per_frame <= 0)
135 return -E_PHYSICAL_WIDTH;
136 if (snd_pcm_nonblock(pad->handle, 1))
137 PARA_ERROR_LOG("failed to set nonblock mode\n");
138 err = snd_output_buffer_open(&log);
139 if (err == 0) {
140 char *buf;
141 PARA_INFO_LOG("dumping alsa configuration\n");
142 snd_pcm_dump(pad->handle, log);
143 snd_output_buffer_string(log, &buf);
144 for (;;) {
145 char *p = strchr(buf, '\n');
146 if (!p) /* omit last output line, it's empty */
147 break;
148 *p = '\0';
149 PARA_INFO_LOG("%s\n", buf);
150 buf = p + 1;
151 }
152 snd_output_close(log);
153 }
154 return 1;
155 }
156
157 static void alsa_write_pre_select(struct sched *s, struct task *t)
158 {
159 struct pollfd pfd;
160 struct writer_node *wn = container_of(t, struct writer_node, task);
161 struct private_alsa_write_data *pad = wn->private_data;
162 int ret = btr_node_status(wn->btrn, wn->min_iqs, BTR_NT_LEAF);
163
164 if (pad)
165 pad->poll_fd = -1;
166 if (ret == 0)
167 return;
168 if (!pad) {
169 sched_min_delay(s);
170 return;
171 }
172 if (ret < 0) {
173 sched_request_barrier_or_min_delay(&pad->drain_barrier, s);
174 return;
175 }
176 ret = snd_pcm_poll_descriptors(pad->handle, &pfd, 1);
177 if (ret < 0) {
178 PARA_ERROR_LOG("%s\n", snd_strerror(-ret));
179 t->error = -E_ALSA_POLL_FDS;
180 return;
181 }
182 pad->poll_fd = pfd.fd;
183 para_fd_set(pfd.fd, &s->rfds, &s->max_fileno);
184 }
185
186 static void alsa_close(struct writer_node *wn)
187 {
188 struct private_alsa_write_data *pad = wn->private_data;
189 PARA_INFO_LOG("closing writer node %p\n", wn);
190
191 if (!pad)
192 return;
193 /*
194 * It's OK to have a blocking operation here because we already made
195 * sure that the PCM output buffer is (nearly) empty.
196 */
197 snd_pcm_nonblock(pad->handle, 0);
198 snd_pcm_drain(pad->handle);
199 snd_pcm_close(pad->handle);
200 snd_config_update_free_global();
201 free(pad);
202 }
203
204 static void alsa_write_post_select(__a_unused struct sched *s,
205 struct task *t)
206 {
207 struct writer_node *wn = container_of(t, struct writer_node, task);
208 struct private_alsa_write_data *pad = wn->private_data;
209 struct btr_node *btrn = wn->btrn;
210 char *data;
211 size_t bytes;
212 snd_pcm_sframes_t frames;
213 int ret;
214
215 again:
216 t->error = 0;
217 ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
218 if (ret == 0)
219 return;
220 btr_merge(btrn, wn->min_iqs);
221 bytes = btr_next_buffer(btrn, &data);
222 if (ret < 0 || bytes < wn->min_iqs) { /* eof */
223 assert(btr_no_parent(btrn));
224 ret = -E_WRITE_COMMON_EOF;
225 if (!pad)
226 goto err;
227 /* wait until pending frames are played */
228 if (pad->drain_barrier.tv_sec == 0) {
229 PARA_DEBUG_LOG("waiting for device to drain\n");
230 tv_add(now, &(struct timeval)EMBRACE(0, 200 * 1000),
231 &pad->drain_barrier);
232 return;
233 }
234 if (tv_diff(now, &pad->drain_barrier, NULL) > 0)
235 goto err;
236 return;
237 }
238 if (!pad) {
239 int32_t val;
240
241 if (bytes == 0) /* no data available */
242 return;
243 pad = para_calloc(sizeof(*pad));
244 get_btr_sample_rate(btrn, &val);
245 pad->sample_rate = val;
246 get_btr_channels(btrn, &val);
247 pad->channels = val;
248 get_btr_sample_format(btrn, &val);
249 pad->sample_format = get_alsa_pcm_format(val);
250
251 PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels,
252 pad->sample_rate);
253 ret = alsa_init(pad, wn->conf);
254 if (ret < 0) {
255 free(pad);
256 goto err;
257 }
258 wn->private_data = pad;
259 wn->min_iqs = pad->bytes_per_frame;
260 goto again;
261 }
262 if (pad->poll_fd < 0 || !FD_ISSET(pad->poll_fd, &s->rfds))
263 return;
264 frames = bytes / pad->bytes_per_frame;
265 frames = snd_pcm_writei(pad->handle, data, frames);
266 if (frames == 0 || frames == -EAGAIN) {
267 /*
268 * The alsa poll fd was ready for IO but we failed to write to
269 * the alsa handle. This means another event is pending. We
270 * don't care about that but we have to dispatch the event in
271 * order to avoid a busy loop. So we simply read from the poll
272 * fd.
273 */
274 char buf[100];
275 if (read(pad->poll_fd, buf, 100))
276 do_nothing;
277 return;
278 }
279 if (frames > 0) {
280 btr_consume(btrn, frames * pad->bytes_per_frame);
281 goto again;
282 }
283 if (frames == -EPIPE) {
284 PARA_WARNING_LOG("underrun (tried to write %zu bytes)\n", bytes);
285 snd_pcm_prepare(pad->handle);
286 return;
287 }
288 PARA_WARNING_LOG("%s\n", snd_strerror(-frames));
289 ret = -E_ALSA_WRITE;
290 err:
291 assert(ret < 0);
292 btr_remove_node(btrn);
293 t->error = ret;
294 }
295
296 __malloc static void *alsa_parse_config_or_die(const char *options)
297 {
298 struct alsa_write_args_info *conf = para_calloc(sizeof(*conf));
299
300 /* exits on errors */
301 alsa_cmdline_parser_string(options, conf, "alsa_write");
302 return conf;
303 }
304
305 static void alsa_free_config(void *conf)
306 {
307 alsa_cmdline_parser_free(conf);
308 }
309
310 /**
311 * The init function of the alsa writer.
312 *
313 * \param w Pointer to the writer to initialize.
314 *
315 * \sa struct \ref writer.
316 */
317 void alsa_write_init(struct writer *w)
318 {
319 struct alsa_write_args_info dummy;
320
321 alsa_cmdline_parser_init(&dummy);
322 w->close = alsa_close;
323 w->pre_select = alsa_write_pre_select;
324 w->post_select = alsa_write_post_select;
325 w->parse_config_or_die = alsa_parse_config_or_die;
326 w->shutdown = NULL; /* nothing to do */
327 w->free_config = alsa_free_config;
328 w->help = (struct ggo_help) {
329 .short_help = alsa_write_args_info_help,
330 .detailed_help = alsa_write_args_info_detailed_help
331 };
332 alsa_cmdline_parser_free(&dummy);
333 }