snd_pcm_rate_bit_to_rate – converts SNDRV_PCM_RATE_xxx bit to sample rate Synopsis unsigned int snd_pcm_rate_bit_to_rate(unsigned int rate_bit); Arguments rate_bit the rate bit to convert Return The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag or 0 for an unknown rate bit. Copyright
snd_pcm_playback_ready – check whether the playback buffer is available Synopsis int snd_pcm_playback_ready(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether enough free space is available on the playback buffer. Return Non-zero if available, or zero if not. Copyright
snd_pcm_playback_hw_avail – Get the queued space for playback Synopsis snd_pcm_sframes_t snd_pcm_playback_hw_avail(struct snd_pcm_runtime * runtime); Arguments runtime PCM runtime instance Copyright
snd_pcm_playback_empty – check whether the playback buffer is empty Synopsis int snd_pcm_playback_empty(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether the playback buffer is empty. Return Non-zero if empty, or zero if not. Copyright
snd_pcm_playback_data – check whether any data exists on the playback buffer Synopsis int snd_pcm_playback_data(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description Checks whether any data exists on the playback buffer. Return Non-zero if any data exists, or zero if not. If stop_threshold is bigger or equal to boundary, then this function returns always…
snd_pcm_playback_avail – Get the available (writable) space for playback Synopsis snd_pcm_uframes_t snd_pcm_playback_avail(struct snd_pcm_runtime * runtime); Arguments runtime PCM runtime instance Description Result is between 0 … (boundary – 1) Copyright
snd_pcm_period_elapsed – update the pcm status for the next period Synopsis void snd_pcm_period_elapsed(struct snd_pcm_substream *substream); Arguments substream the pcm substream instance Description This function is called from the interrupt handler when the PCM has processed the period size. It will update the current pointer, wake up sleepers, etc. Even if more than one periods have…
snd_pcm_notify – Add/remove the notify list Synopsis int snd_pcm_notify(struct snd_pcm_notify *notify, int nfree); Arguments notify PCM notify list nfree 0 = register, 1 = unregister Description This adds the given notifier to the global list so that the callback is called for each registered PCM devices. This exists only for PCM OSS emulation, so far….
snd_pcm_new_stream – create a new PCM stream Synopsis int snd_pcm_new_stream(struct snd_pcm *pcm, int stream, int substream_count); Arguments pcm the pcm instance stream the stream direction, SNDRV_PCM_STREAM_XXX substream_count the number of substreams Description Creates a new stream for the pcm. The corresponding stream on the pcm must have been empty before calling this, i.e. zero must…
snd_pcm_new_internal – create a new internal PCM instance Synopsis int snd_pcm_new_internal(struct snd_card *card, const char *id, int device, int playback_count, int capture_count, struct snd_pcm **rpcm); Arguments card the card instance id the id string device the device index (zero based – shared with normal PCMs) playback_count the number of substreams for playback capture_count the number…
snd_pcm_new – create a new PCM instance Synopsis int snd_pcm_new(struct snd_card *card, const char *id, int device, int playback_count, int capture_count, struct snd_pcm **rpcm); Arguments card the card instance id the id string device the device index (zero based) playback_count the number of substreams for playback capture_count the number of substreams for capture rpcm the…
snd_pcm_mmap_data_open – increase the mmap counter Synopsis void snd_pcm_mmap_data_open(struct vm_area_struct *area); Arguments area VMA Description PCM mmap callback should handle this counter properly Copyright
snd_pcm_mmap_data_close – decrease the mmap counter Synopsis void snd_pcm_mmap_data_close(struct vm_area_struct *area); Arguments area VMA Description PCM mmap callback should handle this counter properly Copyright
snd_pcm_limit_isa_dma_size – Get the max size fitting with ISA DMA transfer Synopsis void snd_pcm_limit_isa_dma_size(int dma, size_t *max); Arguments dma DMA number max pointer to store the max size Copyright
snd_pcm_limit_hw_rates – determine rate_min/rate_max fields Synopsis int snd_pcm_limit_hw_rates(struct snd_pcm_runtime *runtime); Arguments runtime the runtime instance Description Determines the rate_min and rate_max fields from the rates bits of the given runtime->hw. Return Zero if successful. Copyright
snd_pcm_lib_preallocate_pages_for_all – pre-allocation for continuous memory type (all substreams) Synopsis int snd_pcm_lib_preallocate_pages_for_all(struct snd_pcm *pcm, int type, void *data, size_t size, size_t max); Arguments pcm the pcm instance type DMA type (SNDRV_DMA_TYPE_*) data DMA type dependent data size the requested pre-allocation size in bytes max the max. allowed pre-allocation size Description Do pre-allocation to all substreams…
snd_pcm_lib_preallocate_pages – pre-allocation for the given DMA type Synopsis int snd_pcm_lib_preallocate_pages(struct snd_pcm_substream *substream, int type, struct device *data, size_t size, size_t max); Arguments substream the pcm substream instance type DMA type (SNDRV_DMA_TYPE_*) data DMA type dependent data size the requested pre-allocation size in bytes max the max. allowed pre-allocation size Description Do pre-allocation for the…
snd_pcm_lib_preallocate_free_for_all – release all pre-allocated buffers on the pcm Synopsis int snd_pcm_lib_preallocate_free_for_all(struct snd_pcm *pcm); Arguments pcm the pcm instance Description Releases all the pre-allocated buffers on the given pcm. Return Zero if successful, or a negative error code on failure. Copyright
snd_pcm_lib_period_bytes – Get the period size of the current PCM in bytes Synopsis size_t snd_pcm_lib_period_bytes(struct snd_pcm_substream *substream); Arguments substream PCM substream Copyright
snd_pcm_lib_mmap_iomem – Default PCM data mmap function for I/O mem Synopsis int snd_pcm_lib_mmap_iomem(struct snd_pcm_substream *substream, struct vm_area_struct *area); Arguments substream PCM substream area VMA Description When your hardware uses the iomapped pages as the hardware buffer and wants to mmap it, pass this function as mmap pcm_ops. Note that this is supposed to work only…