/* * Helper functions for indirect PCM data transfer to a simple FIFO in * hardware (small, no possibility to read "hardware io position", * updating position done by interrupt, ...) * * Copyright (c) by 2007 Joachim Foerster * * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by * * Copyright (c) by Takashi Iwai * Jaroslav Kysela * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef __SOUND_PCM_INDIRECT2_H #define __SOUND_PCM_INDIRECT2_H /* struct snd_pcm_substream, struct snd_pcm_runtime, snd_pcm_uframes_t */ #include /* Debug options for code which may be removed completely in a final version */ #ifdef CONFIG_SND_DEBUG #define SND_PCM_INDIRECT2_STAT /* turn on some "statistics" about the * process of copying bytes from the * intermediate buffer to the hardware * fifo and the other way round */ #endif struct snd_pcm_indirect2 { unsigned int hw_buffer_size; /* Byte size of hardware buffer */ int hw_ready; /* playback: 1 = hw fifo has room left, * 0 = hw fifo is full */ unsigned int min_multiple; int min_periods; /* counts number of min. periods until * min_multiple is reached */ int min_period_count; /* counts bytes to count number of * min. periods */ unsigned int sw_buffer_size; /* Byte size of software buffer */ /* sw_data: position in intermediate buffer, where we will read (or * write) from/to next time (to transfer data to/from HW) */ unsigned int sw_data; /* Offset to next dst (or src) in sw * ring buffer */ /* easiest case (playback): * sw_data is nearly the same as ~ runtime->control->appl_ptr, with the * exception that sw_data is "behind" by the number if bytes ALSA wrote * to the intermediate buffer last time. * A call to ack() callback synchronizes both indirectly. */ /* We have no real sw_io pointer here. Usually sw_io is pointing to the * current playback/capture position _inside_ the hardware. Devices * with plain FIFOs often have no possibility to publish this position. * So we say: if sw_data is updated, that means bytes were copied to * the hardware, we increase sw_io by that amount, because there have * to be as much bytes which were played. So sw_io will stay behind * sw_data all the time and has to converge to sw_data at the end of * playback. */ unsigned int sw_io; /* Current software pointer in bytes */ /* sw_ready: number of bytes ALSA copied to the intermediate buffer, so * it represents the number of bytes which wait for transfer to the HW */ int sw_ready; /* Bytes ready to be transferred to/from hw */ /* appl_ptr: last known position of ALSA (where ALSA is going to write * next time into the intermediate buffer */ snd_pcm_uframes_t appl_ptr; /* Last seen appl_ptr */ unsigned int bytes2hw; int check_alignment; #ifdef SND_PCM_INDIRECT2_STAT unsigned int zeros2hw; unsigned int mul_elapsed; unsigned int mul_elapsed_real; unsigned long firstbytetime; unsigned long lastbytetime; unsigned long firstzerotime; unsigned int byte_sizes[64]; unsigned int zero_sizes[64]; unsigned int min_adds[8]; unsigned int mul_adds[8]; unsigned int zero_times[3750]; /* = 15s */ unsigned int zero_times_saved; unsigned int zero_times_notsaved; unsigned int irq_occured; unsigned int pointer_calls; unsigned int lastdifftime; #endif }; typedef size_t (*snd_pcm_indirect2_copy_t) (struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec, size_t bytes); typedef size_t (*snd_pcm_indirect2_zero_t) (struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec); #ifdef SND_PCM_INDIRECT2_STAT void snd_pcm_indirect2_stat(struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec); #endif snd_pcm_uframes_t snd_pcm_indirect2_pointer(struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec); void snd_pcm_indirect2_playback_interrupt(struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec, snd_pcm_indirect2_copy_t copy, snd_pcm_indirect2_zero_t zero); void snd_pcm_indirect2_capture_interrupt(struct snd_pcm_substream *substream, struct snd_pcm_indirect2 *rec, snd_pcm_indirect2_copy_t copy, snd_pcm_indirect2_zero_t null); #endif /* __SOUND_PCM_INDIRECT2_H */