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authorTaylor Holberton <taylorcholberton@gmail.com>2017-04-10 12:05:51 -0700
committerTaylor Holberton <taylorcholberton@gmail.com>2017-04-10 12:05:51 -0700
commit861da7ab0565d150bcd5ceb1e6fb812516e4cfee (patch)
tree53502313bc3e361ebc86f87f7a8be2b7874047d9 /src
parentcad23d2482a3f551633c6f10d16ea8f4cb83cdb5 (diff)
moved code in pcm_open() to pcm_set_config()
Diffstat (limited to 'src')
-rw-r--r--src/pcm.c316
1 files changed, 168 insertions, 148 deletions
diff --git a/src/pcm.c b/src/pcm.c
index 8a08e14..24f4f2b 100644
--- a/src/pcm.c
+++ b/src/pcm.c
@@ -160,6 +160,36 @@ static void param_init(struct snd_pcm_hw_params *p)
p->info = ~0U;
}
+static unsigned int pcm_format_to_alsa(enum pcm_format format)
+{
+ switch (format) {
+
+ case PCM_FORMAT_S8:
+ return SNDRV_PCM_FORMAT_S8;
+
+ default:
+ case PCM_FORMAT_S16_LE:
+ return SNDRV_PCM_FORMAT_S16_LE;
+ case PCM_FORMAT_S16_BE:
+ return SNDRV_PCM_FORMAT_S16_BE;
+
+ case PCM_FORMAT_S24_LE:
+ return SNDRV_PCM_FORMAT_S24_LE;
+ case PCM_FORMAT_S24_BE:
+ return SNDRV_PCM_FORMAT_S24_BE;
+
+ case PCM_FORMAT_S24_3LE:
+ return SNDRV_PCM_FORMAT_S24_3LE;
+ case PCM_FORMAT_S24_3BE:
+ return SNDRV_PCM_FORMAT_S24_3BE;
+
+ case PCM_FORMAT_S32_LE:
+ return SNDRV_PCM_FORMAT_S32_LE;
+ case PCM_FORMAT_S32_BE:
+ return SNDRV_PCM_FORMAT_S32_BE;
+ };
+}
+
#define PCM_ERROR_MAX 128
/** A PCM handle.
@@ -195,6 +225,22 @@ struct pcm {
unsigned int subdevice;
};
+static int oops(struct pcm *pcm, int e, const char *fmt, ...)
+{
+ va_list ap;
+ int sz;
+
+ va_start(ap, fmt);
+ vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap);
+ va_end(ap);
+ sz = strlen(pcm->error);
+
+ if (errno)
+ snprintf(pcm->error + sz, PCM_ERROR_MAX - sz,
+ ": %s", strerror(e));
+ return -1;
+}
+
/** Gets the buffer size of the PCM.
* @param pcm A PCM handle.
* @return The buffer size of the PCM.
@@ -272,58 +318,138 @@ const char* pcm_get_error(const struct pcm *pcm)
return pcm->error;
}
-/** Gets the subdevice on which the pcm has been opened.
+/** Sets the PCM configuration.
* @param pcm A PCM handle.
- * @return The subdevice on which the pcm has been opened */
-unsigned int pcm_get_subdevice(const struct pcm *pcm)
+ * @param config The configuration to use for the
+ * PCM. This parameter may be NULL, in which case
+ * the default configuration is used.
+ * @returns Zero on success, a negative errno value
+ * on failure.
+ * @ingroup libtinyalsa-pcm
+ * */
+int pcm_set_config(struct pcm *pcm, const struct pcm_config *config)
{
- return pcm->subdevice;
-}
+ if (pcm == NULL)
+ return -EFAULT;
+ else if (config == NULL) {
+ config = &pcm->config;
+ pcm->config.channels = 2;
+ pcm->config.rate = 48000;
+ pcm->config.period_size = 1024;
+ pcm->config.period_count = 4;
+ pcm->config.format = PCM_FORMAT_S16_LE;
+ pcm->config.start_threshold = config->period_count * config->period_size;
+ pcm->config.stop_threshold = config->period_count * config->period_size;
+ pcm->config.silence_threshold = 0;
+ } else
+ pcm->config = *config;
-static int oops(struct pcm *pcm, int e, const char *fmt, ...)
-{
- va_list ap;
- int sz;
+ struct snd_pcm_hw_params params;
+ param_init(&params);
+ param_set_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT,
+ pcm_format_to_alsa(config->format));
+ param_set_mask(&params, SNDRV_PCM_HW_PARAM_SUBFORMAT,
+ SNDRV_PCM_SUBFORMAT_STD);
+ param_set_min(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size);
+ param_set_int(&params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
+ pcm_format_to_bits(config->format));
+ param_set_int(&params, SNDRV_PCM_HW_PARAM_FRAME_BITS,
+ pcm_format_to_bits(config->format) * config->channels);
+ param_set_int(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
+ config->channels);
+ param_set_int(&params, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
+ param_set_int(&params, SNDRV_PCM_HW_PARAM_RATE, config->rate);
- va_start(ap, fmt);
- vsnprintf(pcm->error, PCM_ERROR_MAX, fmt, ap);
- va_end(ap);
- sz = strlen(pcm->error);
+ if (pcm->flags & PCM_NOIRQ) {
- if (errno)
- snprintf(pcm->error + sz, PCM_ERROR_MAX - sz,
- ": %s", strerror(e));
- return -1;
-}
+ if (!(pcm->flags & PCM_MMAP)) {
+ oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
+ return -EINVAL;
+ }
-static unsigned int pcm_format_to_alsa(enum pcm_format format)
-{
- switch (format) {
+ params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
+ pcm->noirq_frames_per_msec = config->rate / 1000;
+ }
- case PCM_FORMAT_S8:
- return SNDRV_PCM_FORMAT_S8;
+ if (pcm->flags & PCM_MMAP)
+ param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
+ SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
+ else
+ param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
+ SNDRV_PCM_ACCESS_RW_INTERLEAVED);
- default:
- case PCM_FORMAT_S16_LE:
- return SNDRV_PCM_FORMAT_S16_LE;
- case PCM_FORMAT_S16_BE:
- return SNDRV_PCM_FORMAT_S16_BE;
+ if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, &params)) {
+ int errno_copy = errno;
+ oops(pcm, -errno, "cannot set hw params");
+ return -errno_copy;
+ }
- case PCM_FORMAT_S24_LE:
- return SNDRV_PCM_FORMAT_S24_LE;
- case PCM_FORMAT_S24_BE:
- return SNDRV_PCM_FORMAT_S24_BE;
+ /* get our refined hw_params */
+ pcm->config.period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
+ pcm->config.period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
+ pcm->buffer_size = config->period_count * config->period_size;
- case PCM_FORMAT_S24_3LE:
- return SNDRV_PCM_FORMAT_S24_3LE;
- case PCM_FORMAT_S24_3BE:
- return SNDRV_PCM_FORMAT_S24_3BE;
+ if (pcm->flags & PCM_MMAP) {
+ pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size),
+ PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0);
+ if (pcm->mmap_buffer == MAP_FAILED) {
+ int errno_copy = errno;
+ oops(pcm, -errno, "failed to mmap buffer %d bytes\n",
+ pcm_frames_to_bytes(pcm, pcm->buffer_size));
+ return -errno_copy;
+ }
+ }
- case PCM_FORMAT_S32_LE:
- return SNDRV_PCM_FORMAT_S32_LE;
- case PCM_FORMAT_S32_BE:
- return SNDRV_PCM_FORMAT_S32_BE;
- };
+ struct snd_pcm_sw_params sparams;
+ memset(&sparams, 0, sizeof(sparams));
+ sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE;
+ sparams.period_step = 1;
+ sparams.avail_min = 1;
+
+ if (!config->start_threshold) {
+ if (pcm->flags & PCM_IN)
+ pcm->config.start_threshold = sparams.start_threshold = 1;
+ else
+ pcm->config.start_threshold = sparams.start_threshold =
+ config->period_count * config->period_size / 2;
+ } else
+ sparams.start_threshold = config->start_threshold;
+
+ /* pick a high stop threshold - todo: does this need further tuning */
+ if (!config->stop_threshold) {
+ if (pcm->flags & PCM_IN)
+ pcm->config.stop_threshold = sparams.stop_threshold =
+ config->period_count * config->period_size * 10;
+ else
+ pcm->config.stop_threshold = sparams.stop_threshold =
+ config->period_count * config->period_size;
+ }
+ else
+ sparams.stop_threshold = config->stop_threshold;
+
+ sparams.xfer_align = config->period_size / 2; /* needed for old kernels */
+ sparams.silence_size = 0;
+ sparams.silence_threshold = config->silence_threshold;
+ pcm->boundary = sparams.boundary = pcm->buffer_size;
+
+ while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size)
+ pcm->boundary *= 2;
+
+ if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) {
+ int errno_copy = errno;
+ oops(pcm, -errno, "cannot set sw params");
+ return -errno_copy;
+ }
+
+ return 0;
+}
+
+/** Gets the subdevice on which the pcm has been opened.
+ * @param pcm A PCM handle.
+ * @return The subdevice on which the pcm has been opened */
+unsigned int pcm_get_subdevice(const struct pcm *pcm)
+{
+ return pcm->subdevice;
}
/** Determines the number of bits occupied by a @ref pcm_format.
@@ -930,8 +1056,6 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
{
struct pcm *pcm;
struct snd_pcm_info info;
- struct snd_pcm_hw_params params;
- struct snd_pcm_sw_params sparams;
char fn[256];
int rc;
@@ -939,20 +1063,6 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
if (!pcm)
return &bad_pcm;
- if (config == NULL) {
- config = &pcm->config;
- pcm->config.channels = 2;
- pcm->config.rate = 48000;
- pcm->config.period_size = 1024;
- pcm->config.period_count = 4;
- pcm->config.format = PCM_FORMAT_S16_LE;
- pcm->config.start_threshold = config->period_count * config->period_size;
- pcm->config.stop_threshold = config->period_count * config->period_size;
- pcm->config.silence_threshold = 0;
- } else {
- pcm->config = *config;
- }
-
snprintf(fn, sizeof(fn), "/dev/snd/pcmC%uD%u%c", card, device,
flags & PCM_IN ? 'c' : 'p');
@@ -969,98 +1079,8 @@ struct pcm *pcm_open(unsigned int card, unsigned int device,
}
pcm->subdevice = info.subdevice;
- param_init(&params);
- param_set_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT,
- pcm_format_to_alsa(config->format));
- param_set_mask(&params, SNDRV_PCM_HW_PARAM_SUBFORMAT,
- SNDRV_PCM_SUBFORMAT_STD);
- param_set_min(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size);
- param_set_int(&params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS,
- pcm_format_to_bits(config->format));
- param_set_int(&params, SNDRV_PCM_HW_PARAM_FRAME_BITS,
- pcm_format_to_bits(config->format) * config->channels);
- param_set_int(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
- config->channels);
- param_set_int(&params, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count);
- param_set_int(&params, SNDRV_PCM_HW_PARAM_RATE, config->rate);
-
- if (flags & PCM_NOIRQ) {
-
- if (!(flags & PCM_MMAP)) {
- oops(pcm, -EINVAL, "noirq only currently supported with mmap().");
- goto fail;
- }
-
- params.flags |= SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP;
- pcm->noirq_frames_per_msec = config->rate / 1000;
- }
-
- if (flags & PCM_MMAP)
- param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
- SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
- else
- param_set_mask(&params, SNDRV_PCM_HW_PARAM_ACCESS,
- SNDRV_PCM_ACCESS_RW_INTERLEAVED);
-
- if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, &params)) {
- oops(pcm, errno, "cannot set hw params");
+ if (pcm_set_config(pcm, config) != 0)
goto fail_close;
- }
-
- /* get our refined hw_params */
- pcm->config.period_size = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE);
- pcm->config.period_count = param_get_int(&params, SNDRV_PCM_HW_PARAM_PERIODS);
- pcm->buffer_size = config->period_count * config->period_size;
-
- if (flags & PCM_MMAP) {
- pcm->mmap_buffer = mmap(NULL, pcm_frames_to_bytes(pcm, pcm->buffer_size),
- PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, pcm->fd, 0);
- if (pcm->mmap_buffer == MAP_FAILED) {
- oops(pcm, -errno, "failed to mmap buffer %d bytes\n",
- pcm_frames_to_bytes(pcm, pcm->buffer_size));
- goto fail_close;
- }
- }
-
-
- memset(&sparams, 0, sizeof(sparams));
- sparams.tstamp_mode = SNDRV_PCM_TSTAMP_ENABLE;
- sparams.period_step = 1;
- sparams.avail_min = 1;
-
- if (!config->start_threshold) {
- if (pcm->flags & PCM_IN)
- pcm->config.start_threshold = sparams.start_threshold = 1;
- else
- pcm->config.start_threshold = sparams.start_threshold =
- config->period_count * config->period_size / 2;
- } else
- sparams.start_threshold = config->start_threshold;
-
- /* pick a high stop threshold - todo: does this need further tuning */
- if (!config->stop_threshold) {
- if (pcm->flags & PCM_IN)
- pcm->config.stop_threshold = sparams.stop_threshold =
- config->period_count * config->period_size * 10;
- else
- pcm->config.stop_threshold = sparams.stop_threshold =
- config->period_count * config->period_size;
- }
- else
- sparams.stop_threshold = config->stop_threshold;
-
- sparams.xfer_align = config->period_size / 2; /* needed for old kernels */
- sparams.silence_size = 0;
- sparams.silence_threshold = config->silence_threshold;
- pcm->boundary = sparams.boundary = pcm->buffer_size;
-
- while (pcm->boundary * 2 <= INT_MAX - pcm->buffer_size)
- pcm->boundary *= 2;
-
- if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_SW_PARAMS, &sparams)) {
- oops(pcm, errno, "cannot set sw params");
- goto fail;
- }
rc = pcm_hw_mmap_status(pcm);
if (rc < 0) {