| Joachim Foerster | a9f00d8 | 2007-11-05 16:06:01 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Helper functions for indirect PCM data transfer to a simple FIFO in |
| 3 | * hardware (small, no possibility to read "hardware io position", |
| 4 | * updating position done by interrupt, ...) |
| 5 | * |
| 6 | * Copyright (c) by 2007 Joachim Foerster <JOFT@gmx.de> |
| 7 | * |
| 8 | * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by |
| 9 | * |
| 10 | * Copyright (c) by Takashi Iwai <tiwai@suse.de> |
| 11 | * Jaroslav Kysela <perex@suse.cz> |
| 12 | * |
| 13 | * This program is free software; you can redistribute it and/or modify |
| 14 | * it under the terms of the GNU General Public License as published by |
| 15 | * the Free Software Foundation; either version 2 of the License, or |
| 16 | * (at your option) any later version. |
| 17 | * |
| 18 | * This program is distributed in the hope that it will be useful, |
| 19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 21 | * GNU General Public License for more details. |
| 22 | * |
| 23 | * You should have received a copy of the GNU General Public License |
| 24 | * along with this program; if not, write to the Free Software |
| 25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 26 | */ |
| 27 | |
| 28 | #ifndef __SOUND_PCM_INDIRECT2_H |
| 29 | #define __SOUND_PCM_INDIRECT2_H |
| 30 | |
| 31 | /* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */ |
| 32 | #include <sound/pcm.h> |
| 33 | |
| 34 | /* Debug options for code which may be removed completely in a final version */ |
| 35 | #ifdef CONFIG_SND_DEBUG |
| 36 | #define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the |
| 37 | * process of copying bytes from the |
| 38 | * intermediate buffer to the hardware |
| 39 | * fifo and the other way round |
| 40 | */ |
| 41 | #endif |
| 42 | |
| 43 | struct snd_pcm_indirect2 { |
| 44 | unsigned int hw_buffer_size; /* Byte size of hardware buffer */ |
| 45 | int hw_ready; /* playback: 1 = hw fifo has room left, |
| 46 | * 0 = hw fifo is full |
| 47 | */ |
| 48 | unsigned int min_multiple; |
| 49 | int min_periods; /* counts number of min. periods until |
| 50 | * min_multiple is reached |
| 51 | */ |
| 52 | int min_period_count; /* counts bytes to count number of |
| 53 | * min. periods |
| 54 | */ |
| 55 | |
| 56 | unsigned int sw_buffer_size; /* Byte size of software buffer */ |
| 57 | |
| 58 | /* sw_data: position in intermediate buffer, where we will read (or |
| 59 | * write) from/to next time (to transfer data to/from HW) |
| 60 | */ |
| 61 | unsigned int sw_data; /* Offset to next dst (or src) in sw |
| 62 | * ring buffer |
| 63 | */ |
| 64 | /* easiest case (playback): |
| 65 | * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the |
| 66 | * exception that sw_data is "behind" by the number if bytes ALSA wrote |
| 67 | * to the intermediate buffer last time. |
| 68 | * A call to ack() callback synchronizes both indirectly. |
| 69 | */ |
| 70 | |
| 71 | /* We have no real sw_io pointer here. Usually sw_io is pointing to the |
| 72 | * current playback/capture position _inside_ the hardware. Devices |
| 73 | * with plain FIFOs often have no possibility to publish this position. |
| 74 | * So we say: if sw_data is updated, that means bytes were copied to |
| 75 | * the hardware, we increase sw_io by that amount, because there have |
| 76 | * to be as much bytes which were played. So sw_io will stay behind |
| 77 | * sw_data all the time and has to converge to sw_data at the end of |
| 78 | * playback. |
| 79 | */ |
| 80 | unsigned int sw_io; /* Current software pointer in bytes */ |
| 81 | |
| 82 | /* sw_ready: number of bytes ALSA copied to the intermediate buffer, so |
| 83 | * it represents the number of bytes which wait for transfer to the HW |
| 84 | */ |
| 85 | int sw_ready; /* Bytes ready to be transferred to/from hw */ |
| 86 | |
| 87 | /* appl_ptr: last known position of ALSA (where ALSA is going to write |
| 88 | * next time into the intermediate buffer |
| 89 | */ |
| 90 | snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ |
| 91 | |
| 92 | unsigned int bytes2hw; |
| 93 | int check_alignment; |
| 94 | |
| 95 | #ifdef SND_PCM_INDIRECT2_STAT |
| 96 | unsigned int zeros2hw; |
| 97 | unsigned int mul_elapsed; |
| 98 | unsigned int mul_elapsed_real; |
| 99 | unsigned long firstbytetime; |
| 100 | unsigned long lastbytetime; |
| 101 | unsigned long firstzerotime; |
| 102 | unsigned int byte_sizes[64]; |
| 103 | unsigned int zero_sizes[64]; |
| 104 | unsigned int min_adds[8]; |
| 105 | unsigned int mul_adds[8]; |
| 106 | unsigned int zero_times[3750]; /* = 15s */ |
| 107 | unsigned int zero_times_saved; |
| 108 | unsigned int zero_times_notsaved; |
| 109 | unsigned int irq_occured; |
| 110 | unsigned int pointer_calls; |
| 111 | unsigned int lastdifftime; |
| 112 | #endif |
| 113 | }; |
| 114 | |
| 115 | typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream, |
| 116 | struct snd_pcm_indirect2 *rec, |
| 117 | size_t bytes); |
| 118 | typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream, |
| 119 | struct snd_pcm_indirect2 *rec); |
| 120 | |
| 121 | #ifdef SND_PCM_INDIRECT2_STAT |
| 122 | void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream, |
| 123 | struct snd_pcm_indirect2 *rec); |
| 124 | #endif |
| 125 | |
| 126 | snd_pcm_uframes_t |
| 127 | snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream, |
| 128 | struct snd_pcm_indirect2 *rec); |
| 129 | void |
| 130 | snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream, |
| 131 | struct snd_pcm_indirect2 *rec, |
| 132 | snd_pcm_indirect2_copy_t copy, |
| 133 | snd_pcm_indirect2_zero_t zero); |
| 134 | void |
| 135 | snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream, |
| 136 | struct snd_pcm_indirect2 *rec, |
| 137 | snd_pcm_indirect2_copy_t copy, |
| 138 | snd_pcm_indirect2_zero_t null); |
| 139 | |
| 140 | #endif /* __SOUND_PCM_INDIRECT2_H */ |