include/sound/pcm-indirect.h

   1 /*
   2  * Helper functions for indirect PCM data transfer
   3  *
   4  *  Copyright (c) by Takashi Iwai <tiwai@suse.de>
   5  *                   Jaroslav Kysela <perex@perex.cz>
   6  *
   7  *   This program is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU General Public License as published by
   9  *   the Free Software Foundation; either version 2 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This program is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *   GNU General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU General Public License
  18  *   along with this program; if not, write to the Free Software
  19  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #ifndef __SOUND_PCM_INDIRECT_H
  23 #define __SOUND_PCM_INDIRECT_H
  24
  25 #include <sound/pcm.h>
  26
  27 struct snd_pcm_indirect {
  28         unsigned int hw_buffer_size;    /* Byte size of hardware buffer */
  29         unsigned int hw_queue_size;     /* Max queue size of hw buffer (0 = buffer size) */
  30         unsigned int hw_data;   /* Offset to next dst (or src) in hw ring buffer */
  31         unsigned int hw_io;     /* Ring buffer hw pointer */
  32         int hw_ready;           /* Bytes ready for play (or captured) in hw ring buffer */
  33         unsigned int sw_buffer_size;    /* Byte size of software buffer */
  34         unsigned int sw_data;   /* Offset to next dst (or src) in sw ring buffer */
  35         unsigned int sw_io;     /* Current software pointer in bytes */
  36         int sw_ready;           /* Bytes ready to be transferred to/from hw */
  37         snd_pcm_uframes_t appl_ptr;     /* Last seen appl_ptr */
  38 };
  39
  40 typedef void (*snd_pcm_indirect_copy_t)(struct snd_pcm_substream *substream,
  41                                         struct snd_pcm_indirect *rec, size_t bytes);
  42
  43 /*
  44  * helper function for playback ack callback
  45  */
  46 static inline int
  47 snd_pcm_indirect_playback_transfer(struct snd_pcm_substream *substream,
  48                                    struct snd_pcm_indirect *rec,
  49                                    snd_pcm_indirect_copy_t copy)
  50 {
  51         struct snd_pcm_runtime *runtime = substream->runtime;
  52         snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
  53         snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
  54         int qsize;
  55
  56         if (diff) {
  57                 if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
  58                         diff += runtime->boundary;
  59                 if (diff < 0)
  60                         return -EINVAL;
  61                 rec->sw_ready += (int)frames_to_bytes(runtime, diff);
  62                 rec->appl_ptr = appl_ptr;
  63         }
  64         qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size;
  65         while (rec->hw_ready < qsize && rec->sw_ready > 0) {
  66                 unsigned int hw_to_end = rec->hw_buffer_size - rec->hw_data;
  67                 unsigned int sw_to_end = rec->sw_buffer_size - rec->sw_data;
  68                 unsigned int bytes = qsize - rec->hw_ready;
  69                 if (rec->sw_ready < (int)bytes)
  70                         bytes = rec->sw_ready;
  71                 if (hw_to_end < bytes)
  72                         bytes = hw_to_end;
  73                 if (sw_to_end < bytes)
  74                         bytes = sw_to_end;
  75                 if (! bytes)
  76                         break;
  77                 copy(substream, rec, bytes);
  78                 rec->hw_data += bytes;
  79                 if (rec->hw_data == rec->hw_buffer_size)
  80                         rec->hw_data = 0;
  81                 rec->sw_data += bytes;
  82                 if (rec->sw_data == rec->sw_buffer_size)
  83                         rec->sw_data = 0;
  84                 rec->hw_ready += bytes;
  85                 rec->sw_ready -= bytes;
  86         }
  87         return 0;
  88 }
  89
  90 /*
  91  * helper function for playback pointer callback
  92  * ptr = current byte pointer
  93  */
  94 static inline snd_pcm_uframes_t
  95 snd_pcm_indirect_playback_pointer(struct snd_pcm_substream *substream,
  96                                   struct snd_pcm_indirect *rec, unsigned int ptr)
  97 {
  98         int bytes = ptr - rec->hw_io;
  99         if (bytes < 0)
 100                 bytes += rec->hw_buffer_size;
 101         rec->hw_io = ptr;
 102         rec->hw_ready -= bytes;
 103         rec->sw_io += bytes;
 104         if (rec->sw_io >= rec->sw_buffer_size)
 105                 rec->sw_io -= rec->sw_buffer_size;
 106         if (substream->ops->ack)
 107                 substream->ops->ack(substream);
 108         return bytes_to_frames(substream->runtime, rec->sw_io);
 109 }
 110
 111
 112 /*
 113  * helper function for capture ack callback
 114  */
 115 static inline int
 116 snd_pcm_indirect_capture_transfer(struct snd_pcm_substream *substream,
 117                                   struct snd_pcm_indirect *rec,
 118                                   snd_pcm_indirect_copy_t copy)
 119 {
 120         struct snd_pcm_runtime *runtime = substream->runtime;
 121         snd_pcm_uframes_t appl_ptr = runtime->control->appl_ptr;
 122         snd_pcm_sframes_t diff = appl_ptr - rec->appl_ptr;
 123
 124         if (diff) {
 125                 if (diff < -(snd_pcm_sframes_t) (runtime->boundary / 2))
 126                         diff += runtime->boundary;
 127                 if (diff < 0)
 128                         return -EINVAL;
 129                 rec->sw_ready -= frames_to_bytes(runtime, diff);
 130                 rec->appl_ptr = appl_ptr;
 131         }
 132         while (rec->hw_ready > 0 &&
 133                rec->sw_ready < (int)rec->sw_buffer_size) {
 134                 size_t hw_to_end = rec->hw_buffer_size - rec->hw_data;
 135                 size_t sw_to_end = rec->sw_buffer_size - rec->sw_data;
 136                 size_t bytes = rec->sw_buffer_size - rec->sw_ready;
 137                 if (rec->hw_ready < (int)bytes)
 138                         bytes = rec->hw_ready;
 139                 if (hw_to_end < bytes)
 140                         bytes = hw_to_end;
 141                 if (sw_to_end < bytes)
 142                         bytes = sw_to_end;
 143                 if (! bytes)
 144                         break;
 145                 copy(substream, rec, bytes);
 146                 rec->hw_data += bytes;
 147                 if ((int)rec->hw_data == rec->hw_buffer_size)
 148                         rec->hw_data = 0;
 149                 rec->sw_data += bytes;
 150                 if (rec->sw_data == rec->sw_buffer_size)
 151                         rec->sw_data = 0;
 152                 rec->hw_ready -= bytes;
 153                 rec->sw_ready += bytes;
 154         }
 155         return 0;
 156 }
 157
 158 /*
 159  * helper function for capture pointer callback,
 160  * ptr = current byte pointer
 161  */
 162 static inline snd_pcm_uframes_t
 163 snd_pcm_indirect_capture_pointer(struct snd_pcm_substream *substream,
 164                                  struct snd_pcm_indirect *rec, unsigned int ptr)
 165 {
 166         int qsize;
 167         int bytes = ptr - rec->hw_io;
 168         if (bytes < 0)
 169                 bytes += rec->hw_buffer_size;
 170         rec->hw_io = ptr;
 171         rec->hw_ready += bytes;
 172         qsize = rec->hw_queue_size ? rec->hw_queue_size : rec->hw_buffer_size;
 173         if (rec->hw_ready > qsize)
 174                 return SNDRV_PCM_POS_XRUN;
 175         rec->sw_io += bytes;
 176         if (rec->sw_io >= rec->sw_buffer_size)
 177                 rec->sw_io -= rec->sw_buffer_size;
 178         if (substream->ops->ack)
 179                 substream->ops->ack(substream);
 180         return bytes_to_frames(substream->runtime, rec->sw_io);
 181 }
 182
 183 #endif /* __SOUND_PCM_INDIRECT_H */