| 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */
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| 2 | /*
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| 3 | * Helper functions for indirect PCM data transfer to a simple FIFO in
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| 4 | * hardware (small, no possibility to read "hardware io position",
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| 5 | * updating position done by interrupt, ...)
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| 6 | *
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| 7 | * Copyright (c) by 2007 Joachim Foerster <JOFT@gmx.de>
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| 8 | *
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| 9 | * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by
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| 10 | *
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| 11 | * Copyright (c) by Takashi Iwai <tiwai@suse.de>
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| 12 | * Jaroslav Kysela <perex@suse.cz>
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| 13 | */
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| 14 |
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| 15 | #ifndef __SOUND_PCM_INDIRECT2_H
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| 16 | #define __SOUND_PCM_INDIRECT2_H
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| 17 |
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| 18 | /* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */
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| 19 | #include <sound/pcm.h>
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| 20 |
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| 21 | /* Debug options for code which may be removed completely in a final version */
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| 22 | #ifdef CONFIG_SND_DEBUG
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| 23 | #define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the
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| 24 | * process of copying bytes from the
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| 25 | * intermediate buffer to the hardware
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| 26 | * fifo and the other way round
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| 27 | */
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| 28 | #endif
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| 29 |
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| 30 | struct snd_pcm_indirect2 {
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| 31 | unsigned int hw_buffer_size; /* Byte size of hardware buffer */
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| 32 | int hw_ready; /* playback: 1 = hw fifo has room left,
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| 33 | * 0 = hw fifo is full
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| 34 | */
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| 35 | unsigned int min_multiple;
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| 36 | int min_periods; /* counts number of min. periods until
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| 37 | * min_multiple is reached
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| 38 | */
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| 39 | int min_period_count; /* counts bytes to count number of
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| 40 | * min. periods
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| 41 | */
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| 42 |
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| 43 | unsigned int sw_buffer_size; /* Byte size of software buffer */
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| 44 |
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| 45 | /* sw_data: position in intermediate buffer, where we will read (or
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| 46 | * write) from/to next time (to transfer data to/from HW)
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| 47 | */
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| 48 | unsigned int sw_data; /* Offset to next dst (or src) in sw
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| 49 | * ring buffer
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| 50 | */
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| 51 | /* easiest case (playback):
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| 52 | * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the
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| 53 | * exception that sw_data is "behind" by the number if bytes ALSA wrote
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| 54 | * to the intermediate buffer last time.
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| 55 | * A call to ack() callback synchronizes both indirectly.
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| 56 | */
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| 57 |
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| 58 | /* We have no real sw_io pointer here. Usually sw_io is pointing to the
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| 59 | * current playback/capture position _inside_ the hardware. Devices
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| 60 | * with plain FIFOs often have no possibility to publish this position.
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| 61 | * So we say: if sw_data is updated, that means bytes were copied to
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| 62 | * the hardware, we increase sw_io by that amount, because there have
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| 63 | * to be as much bytes which were played. So sw_io will stay behind
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| 64 | * sw_data all the time and has to converge to sw_data at the end of
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| 65 | * playback.
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| 66 | */
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| 67 | unsigned int sw_io; /* Current software pointer in bytes */
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| 68 |
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| 69 | /* sw_ready: number of bytes ALSA copied to the intermediate buffer, so
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| 70 | * it represents the number of bytes which wait for transfer to the HW
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| 71 | */
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| 72 | int sw_ready; /* Bytes ready to be transferred to/from hw */
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| 73 |
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| 74 | /* appl_ptr: last known position of ALSA (where ALSA is going to write
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| 75 | * next time into the intermediate buffer
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| 76 | */
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| 77 | snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */
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| 78 |
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| 79 | unsigned int bytes2hw;
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| 80 | int check_alignment;
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| 81 |
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| 82 | #ifdef SND_PCM_INDIRECT2_STAT
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| 83 | unsigned int zeros2hw;
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| 84 | unsigned int mul_elapsed;
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| 85 | unsigned int mul_elapsed_real;
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| 86 | unsigned long firstbytetime;
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| 87 | unsigned long lastbytetime;
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| 88 | unsigned long firstzerotime;
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| 89 | unsigned int byte_sizes[64];
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| 90 | unsigned int zero_sizes[64];
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| 91 | unsigned int min_adds[8];
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| 92 | unsigned int mul_adds[8];
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| 93 | unsigned int zero_times[3750]; /* = 15s */
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| 94 | unsigned int zero_times_saved;
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| 95 | unsigned int zero_times_notsaved;
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| 96 | unsigned int irq_occured;
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| 97 | unsigned int pointer_calls;
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| 98 | unsigned int lastdifftime;
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| 99 | #endif
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| 100 | };
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| 101 |
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| 102 | typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream,
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| 103 | struct snd_pcm_indirect2 *rec,
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| 104 | size_t bytes);
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| 105 | typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream,
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| 106 | struct snd_pcm_indirect2 *rec);
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| 107 |
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| 108 | #ifdef SND_PCM_INDIRECT2_STAT
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| 109 | void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream,
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| 110 | struct snd_pcm_indirect2 *rec);
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| 111 | #endif
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| 112 |
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| 113 | snd_pcm_uframes_t
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| 114 | snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream,
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| 115 | struct snd_pcm_indirect2 *rec);
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| 116 | void
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| 117 | snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream,
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| 118 | struct snd_pcm_indirect2 *rec,
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| 119 | snd_pcm_indirect2_copy_t copy,
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| 120 | snd_pcm_indirect2_zero_t zero);
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| 121 | void
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| 122 | snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream,
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| 123 | struct snd_pcm_indirect2 *rec,
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| 124 | snd_pcm_indirect2_copy_t copy,
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| 125 | snd_pcm_indirect2_zero_t null);
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| 126 |
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| 127 | #endif /* __SOUND_PCM_INDIRECT2_H */
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