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 */ 141