100 строки
3.3 KiB
C
100 строки
3.3 KiB
C
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/*
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**********************************************************************
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* passthrough.h -- Emu10k1 digital passthrough header file
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* Copyright (C) 2001 Juha Yrj<EFBFBD>l<EFBFBD> <jyrjola@cc.hut.fi>
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*
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**********************************************************************
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*
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* Date Author Summary of changes
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* ---- ------ ------------------
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* May 15, 2001 Juha Yrj<EFBFBD>l<EFBFBD> base code release
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*
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**********************************************************************
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the Free
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* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139,
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* USA.
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*
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**********************************************************************
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*/
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#ifndef _PASSTHROUGH_H
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#define _PASSTHROUGH_H
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#include "audio.h"
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/* number of 16-bit stereo samples in XTRAM buffer */
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#define PT_SAMPLES 0x8000
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#define PT_BLOCKSAMPLES 0x400
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#define PT_BLOCKSIZE (PT_BLOCKSAMPLES*4)
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#define PT_BLOCKSIZE_LOG2 12
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#define PT_BLOCKCOUNT (PT_SAMPLES/PT_BLOCKSAMPLES)
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#define PT_INITPTR (PT_SAMPLES/2-1)
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#define PT_STATE_INACTIVE 0
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#define PT_STATE_ACTIVATED 1
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#define PT_STATE_PLAYING 2
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/* passthrough struct */
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struct pt_data
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{
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u8 selected, state, spcs_to_use;
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int intr_gpr, enable_gpr, pos_gpr;
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u32 blocks_played, blocks_copied, old_spcs[3];
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u32 playptr, copyptr;
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u32 prepend_size;
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u8 *buf;
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u8 ac3data;
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char *patch_name, *intr_gpr_name, *enable_gpr_name, *pos_gpr_name;
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wait_queue_head_t wait;
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spinlock_t lock;
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};
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/*
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Passthrough can be done in two methods:
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Method 1 : tram
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In original emu10k1, we couldn't bypass the sample rate converters. Even at 48kHz
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(the internal sample rate of the emu10k1) the samples would get messed up.
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To over come this, samples are copied into the tram and a special dsp patch copies
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the samples out and generates interrupts when a block has finnished playing.
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Method 2 : Interpolator bypass
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Creative fixed the sample rate convert problem in emu10k1 rev 7 and higher
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(including the emu10k2 (audigy)). This allows us to use the regular, and much simpler
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playback method.
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In both methods, dsp code is used to mux audio and passthrough. This ensures that the spdif
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doesn't receive audio and pasthrough data at the same time. The spdif flag SPCS_NOTAUDIODATA
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is set to tell
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*/
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// emu10k1 revs greater than or equal to 7 can use method2
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#define USE_PT_METHOD2 (card->is_audigy)
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#define USE_PT_METHOD1 !USE_PT_METHOD2
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ssize_t emu10k1_pt_write(struct file *file, const char __user *buf, size_t count);
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int emu10k1_pt_setup(struct emu10k1_wavedevice *wave_dev);
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void emu10k1_pt_stop(struct emu10k1_card *card);
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void emu10k1_pt_waveout_update(struct emu10k1_wavedevice *wave_dev);
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#endif /* _PASSTHROUGH_H */
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