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Diffstat (limited to 'sound/drivers/pcm-indirect2.h')
| -rw-r--r-- | sound/drivers/pcm-indirect2.h | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/sound/drivers/pcm-indirect2.h b/sound/drivers/pcm-indirect2.h new file mode 100644 index 000000000..2ea6e460f --- /dev/null +++ b/sound/drivers/pcm-indirect2.h @@ -0,0 +1,140 @@ +/* + * 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 <JOFT@gmx.de> + * + * Based on "pcm-indirect.h" (alsa-driver-1.0.13) by + * + * Copyright (c) by Takashi Iwai <tiwai@suse.de> + * Jaroslav Kysela <perex@suse.cz> + * + * 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 <sound/pcm.h> + +/* 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 */ |