diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/pcm.c | 316 |
1 files changed, 168 insertions, 148 deletions
@@ -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(¶ms); + param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT, + pcm_format_to_alsa(config->format)); + param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT, + SNDRV_PCM_SUBFORMAT_STD); + param_set_min(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, + pcm_format_to_bits(config->format)); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_FRAME_BITS, + pcm_format_to_bits(config->format) * config->channels); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_CHANNELS, + config->channels); + param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count); + param_set_int(¶ms, 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(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, + SNDRV_PCM_ACCESS_MMAP_INTERLEAVED); + else + param_set_mask(¶ms, 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, ¶ms)) { + 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(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); + pcm->config.period_count = param_get_int(¶ms, 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(¶ms); - param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_FORMAT, - pcm_format_to_alsa(config->format)); - param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_SUBFORMAT, - SNDRV_PCM_SUBFORMAT_STD); - param_set_min(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, config->period_size); - param_set_int(¶ms, SNDRV_PCM_HW_PARAM_SAMPLE_BITS, - pcm_format_to_bits(config->format)); - param_set_int(¶ms, SNDRV_PCM_HW_PARAM_FRAME_BITS, - pcm_format_to_bits(config->format) * config->channels); - param_set_int(¶ms, SNDRV_PCM_HW_PARAM_CHANNELS, - config->channels); - param_set_int(¶ms, SNDRV_PCM_HW_PARAM_PERIODS, config->period_count); - param_set_int(¶ms, 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(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, - SNDRV_PCM_ACCESS_MMAP_INTERLEAVED); - else - param_set_mask(¶ms, SNDRV_PCM_HW_PARAM_ACCESS, - SNDRV_PCM_ACCESS_RW_INTERLEAVED); - - if (ioctl(pcm->fd, SNDRV_PCM_IOCTL_HW_PARAMS, ¶ms)) { - 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(¶ms, SNDRV_PCM_HW_PARAM_PERIOD_SIZE); - pcm->config.period_count = param_get_int(¶ms, 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) { |