128 строки
4.4 KiB
C
128 строки
4.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* Helper functions for indirect PCM data transfer to a simple FIFO in
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* hardware (small, no possibility to read "hardware io position",
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* updating position done by interrupt, ...)
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*
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* Copyright (c) by 2007 Joachim Foerster <JOFT@gmx.de>
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*
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* Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
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*
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* Copyright (c) by Takashi Iwai <tiwai@suse.de>
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* Jaroslav Kysela <perex@suse.cz>
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*/
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#ifndef __SOUND_PCM_INDIRECT2_H
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#define __SOUND_PCM_INDIRECT2_H
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/* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */
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#include <sound/pcm.h>
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/* Debug options for code which may be removed completely in a final version */
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#ifdef CONFIG_SND_DEBUG
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#define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the
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* process of copying bytes from the
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* intermediate buffer to the hardware
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* fifo and the other way round
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*/
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#endif
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struct snd_pcm_indirect2 {
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unsigned int hw_buffer_size; /* Byte size of hardware buffer */
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int hw_ready; /* playback: 1 = hw fifo has room left,
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* 0 = hw fifo is full
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*/
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unsigned int min_multiple;
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int min_periods; /* counts number of min. periods until
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* min_multiple is reached
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*/
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int min_period_count; /* counts bytes to count number of
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* min. periods
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*/
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unsigned int sw_buffer_size; /* Byte size of software buffer */
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/* sw_data: position in intermediate buffer, where we will read (or
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* write) from/to next time (to transfer data to/from HW)
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*/
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unsigned int sw_data; /* Offset to next dst (or src) in sw
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* ring buffer
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*/
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/* easiest case (playback):
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* sw_data is nearly the same as ~ runtime->control->appl_ptr, with the
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* exception that sw_data is "behind" by the number if bytes ALSA wrote
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* to the intermediate buffer last time.
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* A call to ack() callback synchronizes both indirectly.
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*/
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/* We have no real sw_io pointer here. Usually sw_io is pointing to the
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* current playback/capture position _inside_ the hardware. Devices
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* with plain FIFOs often have no possibility to publish this position.
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* So we say: if sw_data is updated, that means bytes were copied to
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* the hardware, we increase sw_io by that amount, because there have
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* to be as much bytes which were played. So sw_io will stay behind
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* sw_data all the time and has to converge to sw_data at the end of
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* playback.
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*/
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unsigned int sw_io; /* Current software pointer in bytes */
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/* sw_ready: number of bytes ALSA copied to the intermediate buffer, so
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* it represents the number of bytes which wait for transfer to the HW
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*/
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int sw_ready; /* Bytes ready to be transferred to/from hw */
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/* appl_ptr: last known position of ALSA (where ALSA is going to write
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* next time into the intermediate buffer
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*/
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snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */
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unsigned int bytes2hw;
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int check_alignment;
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#ifdef SND_PCM_INDIRECT2_STAT
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unsigned int zeros2hw;
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unsigned int mul_elapsed;
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unsigned int mul_elapsed_real;
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unsigned long firstbytetime;
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unsigned long lastbytetime;
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unsigned long firstzerotime;
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unsigned int byte_sizes[64];
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unsigned int zero_sizes[64];
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unsigned int min_adds[8];
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unsigned int mul_adds[8];
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unsigned int zero_times[3750]; /* = 15s */
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unsigned int zero_times_saved;
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unsigned int zero_times_notsaved;
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unsigned int irq_occured;
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unsigned int pointer_calls;
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unsigned int lastdifftime;
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#endif
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};
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typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec,
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size_t bytes);
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typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec);
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#ifdef SND_PCM_INDIRECT2_STAT
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void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec);
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#endif
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snd_pcm_uframes_t
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snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec);
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void
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snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec,
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snd_pcm_indirect2_copy_t copy,
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snd_pcm_indirect2_zero_t zero);
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void
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snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
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struct snd_pcm_indirect2 *rec,
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snd_pcm_indirect2_copy_t copy,
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snd_pcm_indirect2_zero_t null);
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#endif /* __SOUND_PCM_INDIRECT2_H */
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