68c4406a91
signals delivered to a process writing to the audio device the
system: if you try
cat /dev/zero > /dev/dsp (or cat /dev/zero > /dev/pcaudio)
and press Ctrl-C : for a second or two the system appears to freeze
(e.g. the cursor will disappear if you move the mouse, xclock
blocks, etc.). I think that interrupts etc. still run so the problem
is not too terrible, but still annoying
[ The problems appears to also be in isa/pcaudio.c, though that is ignored ]
Submitted by: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
779 lines
23 KiB
C
779 lines
23 KiB
C
/*
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* snd/dmabuf.c
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*
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* This file implements the new DMA routines for the sound driver.
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* AUTO DMA MODE (ISA DMA SIDE).
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*
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* Copyright by Luigi Rizzo - 1997
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <i386/isa/snd/sound.h>
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#include <i386/isa/sound/ulaw.h>
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#define MIN_CHUNK_SIZE 256 /* for uiomove etc. */
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#define DMA_ALIGN_THRESHOLD 4
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#define DMA_ALIGN_MASK (~ (DMA_ALIGN_THRESHOLD - 1))
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static void dsp_wr_dmadone(snddev_info *d);
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static void dsp_rd_dmadone(snddev_info *d);
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/*
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* SOUND OUTPUT
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We use a circular buffer to store samples directed to the DAC.
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The buffer is split into two variable-size regions, each identified
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by an offset in the buffer (rp,fp) and a length (rl,fl):
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0 rp,rl fp,fl bufsize
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|__________>____________>________|
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FREE d READY w FREE
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READY: data written from the process and ready to be sent to the DAC;
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FREE: free part of the buffer.
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Both regions can wrap around the end of the buffer. At initialization,
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READY is empty, FREE takes all the available space, and dma is
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idle. dl contains the length of the current DMA transfer, dl=0
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means that the dma is idle.
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The two boundaries (rp,fp) in the buffers are advanced by DMA [d]
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and write() [w] operations. The first portion of the READY region
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is used for DMA transfers. The transfer is started at rp and with
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chunks of length dl. During DMA operations, dsp_wr_dmaupdate()
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updates rp, rl and fl tracking the ISA DMA engine as the transfer
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makes progress.
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When a new block is written, fp advances and rl,fl are updated
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accordingly.
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The code works as follows: the user write routine dsp_write_body()
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fills up the READY region with new data (reclaiming space from the
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FREE region) and starts the write DMA engine if inactive. When a
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DMA transfer is complete, an interrupt causes dsp_wrintr() to be
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called which extends the FREE region and possibly starts the next
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transfer.
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In some cases, the code tries to track the current status of DMA
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operations by calling dsp_wr_dmaupdate() which changes rp, rl and fl.
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The sistem tries to make all DMA transfers use the same size,
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play_blocksize or rec_blocksize. The size is either selected by
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the user, or computed by the system to correspond to about .25s of
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audio. The blocksize must be within a range which is currently:
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min(5ms, 40 bytes) ... 1/2 buffer size.
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When there aren't enough data (write) or space (read), a transfer
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is started with a reduced size.
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To reduce problems in case of overruns, the routine which fills up
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the buffer should initialize (e.g. by repeating the last value) a
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reasonably long area after the last block so that no noise is
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produced on overruns.
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*
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*/
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/*
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* dsp_wr_dmadone() updates pointers and wakes up any process sleeping
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* or waiting on a select().
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* Must be called at spltty().
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*/
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static void
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dsp_wr_dmadone(snddev_info *d)
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{
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snd_dbuf *b = & (d->dbuf_out) ;
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dsp_wr_dmaupdate(b);
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/*
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* XXX here it would be more efficient to record if there
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* actually is a sleeping process, but this should still work.
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*/
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wakeup(b); /* wakeup possible sleepers */
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if (b->sel.si_pid &&
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( !(d->flags & SND_F_HAS_SIZE) || b->fl >= d->play_blocksize ) )
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selwakeup( & b->sel );
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}
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/*
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* dsp_wr_dmaupdate() tracks the status of a (write) dma transfer,
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* updating pointers. It must be called at spltty() and the ISA DMA must
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* have been started.
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*
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* NOTE: when we are using auto dma in the device, rl might become
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* negative.
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*/
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void
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dsp_wr_dmaupdate(snd_dbuf *b)
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{
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int tmp, delta;
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tmp = b->bufsize - isa_dmastatus1(b->chan) ;
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tmp &= DMA_ALIGN_MASK; /* align... */
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delta = tmp - b->rp;
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if (delta < 0) /* wrapped */
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delta += b->bufsize ;
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b->rp = tmp;
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b->rl -= delta ;
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b->fl += delta ;
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b->total += delta ;
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}
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/*
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* Write interrupt routine. Can be called from other places (e.g.
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* to start a paused transfer), but with interrupts disabled.
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*/
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void
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dsp_wrintr(snddev_info *d)
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{
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snd_dbuf *b = & (d->dbuf_out) ;
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if (b->dl) { /* dma was active */
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b->int_count++;
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dsp_wr_dmadone(d);
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}
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DEB(if (b->rl < 0)
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printf("dsp_wrintr: dl %d, rp:rl %d:%d, fp:fl %d:%d\n",
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b->dl, b->rp, b->rl, b->fp, b->fl));
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/*
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* start another dma operation only if have ready data in the buffer,
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* there is no pending abort, have a full-duplex device, or have a
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* half duplex device and there is no pending op on the other side.
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*
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* Force transfers to be aligned to a boundary of 4, which is
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* needed when doing stereo and 16-bit. We could make this
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* adaptive, but why bother for now...
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*/
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if ( b->rl >= DMA_ALIGN_THRESHOLD &&
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! (d->flags & SND_F_ABORTING) &&
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( FULL_DUPLEX(d) || ! (d->flags & SND_F_READING) ) ) {
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int l = min(b->rl, d->play_blocksize ); /* avoid too large transfer */
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l &= DMA_ALIGN_MASK ; /* realign things */
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/*
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* check if we need to reprogram the DMA on the sound card.
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* This happens if the size has changed _and_ the new size
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* is smaller, or it matches the blocksize.
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*/
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if (l != b->dl && (l < b->dl || l == d->play_blocksize) ) {
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/* for any reason, size has changed. Stop and restart */
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DEB(printf("wrintr: bsz change from %d to %d, rp %d rl %d\n",
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b->dl, l, b->rp, b->rl));
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d->callback(d, SND_CB_WR | SND_CB_STOP );
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/*
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* at high speed, it might well be that the count
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* changes in the meantime. So we try to update b->rl
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*/
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dsp_wr_dmaupdate(b) ;
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l = min(b->rl, d->play_blocksize );
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l &= DMA_ALIGN_MASK ; /* realign things */
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b->dl = l; /* record previous transfer size */
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d->callback(d, SND_CB_WR | SND_CB_START );
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}
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} else {
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/* cannot start a new dma transfer */
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DEB(printf("cannot start wr-dma flags 0x%08x rp %d rl %d\n",
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d->flags, b->rp, b->rl));
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if (b->dl > 0) { /* was active */
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b->dl = 0;
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d->callback(d, SND_CB_WR | SND_CB_STOP ); /* stop dma */
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if (d->flags & SND_F_WRITING)
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DEB(printf("Race! got wrint while reloading...\n"));
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else if (b->rl <= 0) /* XXX added 980110 lr */
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reset_dbuf(b, SND_CHAN_WR);
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}
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/*
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* if switching to read, should start the read dma...
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*/
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if ( !FULL_DUPLEX(d) && (d->flags & SND_F_READING) )
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dsp_rdintr(d);
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}
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}
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/*
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* user write routine
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*
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* advance the boundary between READY and FREE, fill the space with
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* uiomove(), and possibly start DMA. Do the above until the transfer
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* is complete.
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*
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* To minimize latency in case a pending DMA transfer is about to end,
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* we do the transfer in pieces of increasing sizes, extending the
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* READY area at every checkpoint. In the (necessary) assumption that
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* memory bandwidth is larger than the rate at which the dma consumes
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* data, we reduce the latency to something proportional to the length
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* of the first piece, while keeping the overhead low and being able
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* to feed the DMA with large blocks.
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*
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* assume d->flags |= SND_F_WRITING ; has been done before
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*/
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int
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dsp_write_body(snddev_info *d, struct uio *buf)
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{
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int n, l, bsz, ret = 0 ;
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long s;
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snd_dbuf *b = & (d->dbuf_out) ;
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/*
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* bsz is the max size for the next transfer. If the dma was idle
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* (dl == 0), we want it as large as possible. Otherwise, start with
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* a small block to avoid underruns if we are close to the end of
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* the previous operation.
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*/
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bsz = b->dl ? MIN_CHUNK_SIZE : b->bufsize ;
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while ( (n = buf->uio_resid) ) {
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l = min (n, bsz); /* at most n bytes ... */
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s = spltty(); /* no interrupts here ... */
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dsp_wr_dmaupdate(b);
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l = min( l, b->fl ); /* no more than avail. space */
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DEB(printf("dsp_write_body: prepare %d bytes out of %d\n", l,n));
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/*
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* at this point, we assume that if l==0 the dma engine
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* must be running.
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*/
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if (l == 0) { /* no space, must sleep */
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int timeout;
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if (d->flags & SND_F_NBIO) {
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/* unless of course we are doing non-blocking i/o */
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splx(s);
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break;
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}
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DEB(printf("dsp_write_body: l=0, (fl %d) sleeping\n", b->fl));
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if ( b->fl < n )
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timeout = hz;
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else
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timeout = 1 ;
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ret = tsleep( (caddr_t)b, PRIBIO|PCATCH, "dspwr", timeout);
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if (ret == EINTR || ret == ERESTART)
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d->flags |= SND_F_ABORTING ;
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splx(s);
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if (ret == EINTR)
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break ;
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continue;
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}
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splx(s);
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/*
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* copy data to the buffer, and possibly do format
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* conversions (here, from ULAW to U8).
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* NOTE: I can use fp here since it is not modified by the
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* interrupt routines.
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*/
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if (b->fp + l > b->bufsize) {
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int l1 = b->bufsize - b->fp ;
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uiomove(b->buf + b->fp, l1, buf) ;
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uiomove(b->buf, l - l1, buf) ;
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if (d->flags & SND_F_XLAT8) {
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translate_bytes(ulaw_dsp, b->buf + b->fp, l1);
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translate_bytes(ulaw_dsp, b->buf , l - l1);
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}
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} else {
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uiomove(b->buf + b->fp, l, buf) ;
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if (d->flags & SND_F_XLAT8)
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translate_bytes(ulaw_dsp, b->buf + b->fp, l);
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}
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s = spltty(); /* no interrupts here ... */
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b->rl += l ; /* this more ready bytes */
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b->fl -= l ; /* this less free bytes */
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b->fp += l ;
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if (b->fp >= b->bufsize) /* handle wraps */
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b->fp -= b->bufsize ;
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if ( b->dl == 0 ) /* dma was idle, restart it */
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dsp_wrintr(d) ;
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splx(s) ;
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if (buf->uio_resid == 0 && (b->fp & (b->sample_size - 1)) == 0) {
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/*
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* If data is correctly aligned, pad the region with
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* replicas of the last sample. l0 goes from current to
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* the buffer end, l1 is the portion which wraps around.
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*/
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int l0, l1, i;
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l1 = min(/* b->dl */ d->play_blocksize, b->fl);
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l0 = min (l1, b->bufsize - b->fp);
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l1 = l1 - l0 ;
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i = b->fp - b->sample_size;
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if (i < 0 ) i += b->bufsize ;
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if (b->sample_size == 1) {
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u_char *p= (u_char *)(b->buf + i), sample = *p;
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for ( ; l0 ; l0--)
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*p++ = sample ;
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for (p= (u_char *)(b->buf) ; l1 ; l1--)
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*p++ = sample ;
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} else if (b->sample_size == 2) {
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u_short *p= (u_short *)(b->buf + i), sample = *p;
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l1 /= 2 ;
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l0 /= 2 ;
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for ( ; l0 ; l0--)
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*p++ = sample ;
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for (p= (u_short *)(b->buf) ; l1 ; l1--)
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*p++ = sample ;
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} else { /* must be 4 ... */
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u_long *p= (u_long *)(b->buf + i), sample = *p;
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l1 /= 4 ;
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l0 /= 4 ;
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for ( ; l0 ; l0--)
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*p++ = sample ;
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for (p= (u_long *)(b->buf) ; l1 ; l1--)
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*p++ = sample ;
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}
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}
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bsz = min(b->bufsize, bsz*2);
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}
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s = spltty(); /* no interrupts here ... */
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d->flags &= ~SND_F_WRITING ;
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if (d->flags & SND_F_ABORTING) {
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d->flags &= ~SND_F_ABORTING;
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splx(s);
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dsp_wrabort(d, 1 /* restart */);
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/* XXX return EINTR ? */
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}
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splx(s) ;
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return ret ;
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}
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/*
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* SOUND INPUT
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*
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The input part is similar to the output one, with a circular buffer
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split in two regions, and boundaries advancing because of read() calls
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[r] or dma operation [d]. At initialization, as for the write
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routine, READY is empty, and FREE takes all the space.
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0 rp,rl fp,fl bufsize
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|__________>____________>________|
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FREE r READY d FREE
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Operation is as follows: upon user read (dsp_read_body()) a DMA read
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is started if not already active (marked by b->dl > 0),
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then as soon as data are available in the READY region they are
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transferred to the user buffer, thus advancing the boundary between FREE
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and READY. Upon interrupts, caused by a completion of a DMA transfer,
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the READY region is extended and possibly a new transfer is started.
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When necessary, dsp_rd_dmaupdate() is called to advance fp (and update
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rl,fl accordingly). Upon user reads, rp is advanced and rl,fl are
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updated accordingly.
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The rules to choose the size of the new DMA area are similar to
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the other case, with a preferred constant transfer size equal to
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rec_blocksize, and fallback to smaller sizes if no space is available.
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*
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*/
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/*
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* dsp_rd_dmadone moves bytes in the input buffer from DMA region to
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* READY region. We assume it is called at spltty() and with dl>0
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*/
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static void
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dsp_rd_dmadone(snddev_info *d)
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{
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snd_dbuf *b = & (d->dbuf_in) ;
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dsp_rd_dmaupdate(b);
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wakeup(b) ; /* wakeup possibly sleeping processes */
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if (b->sel.si_pid &&
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( !(d->flags & SND_F_HAS_SIZE) || b->rl >= d->rec_blocksize ) )
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selwakeup( & b->sel );
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}
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/*
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* The following function tracks the status of a (read) dma transfer,
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* and moves the boundary between the READY and the DMA regions.
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* It works under the following assumptions:
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* - the DMA engine is running;
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* - the function is called with interrupts blocked.
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*/
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void
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dsp_rd_dmaupdate(snd_dbuf *b)
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{
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int delta, tmp ;
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tmp = b->bufsize - isa_dmastatus1(b->chan) ;
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tmp &= DMA_ALIGN_MASK; /* align... */
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delta = tmp - b->fp;
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if (delta < 0) /* wrapped */
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delta += b->bufsize ;
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b->fp = tmp;
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b->fl -= delta ;
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b->rl += delta ;
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b->total += delta ;
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}
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/*
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* read interrupt routine. Must be called with interrupts blocked.
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*/
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void
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dsp_rdintr(snddev_info *d)
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{
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snd_dbuf *b = & (d->dbuf_in) ;
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if (b->dl) { /* dma was active */
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b->int_count++;
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dsp_rd_dmadone(d);
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}
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DEB(printf("dsp_rdintr: start dl %d, rp:rl %d:%d, fp:fl %d:%d\n",
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b->dl, b->rp, b->rl, b->fp, b->fl));
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/*
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* Restart if have enough free space to absorb overruns;
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*/
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if ( b->fl > 0x200 &&
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(d->flags & (SND_F_ABORTING|SND_F_CLOSING)) == 0 &&
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( FULL_DUPLEX(d) || (d->flags & SND_F_WRITING) == 0 ) ) {
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int l = min(b->fl - 0x100, d->rec_blocksize);
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l &= DMA_ALIGN_MASK ; /* realign sizes */
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if (l != b->dl) {
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/* for any reason, size has changed. Stop and restart */
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b->dl = l ;
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d->callback(d, SND_CB_RD | SND_CB_STOP );
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d->callback(d, SND_CB_RD | SND_CB_START );
|
|
}
|
|
} else {
|
|
if (b->dl > 0) { /* was active */
|
|
b->dl = 0;
|
|
d->callback(d, SND_CB_RD | SND_CB_STOP);
|
|
}
|
|
/*
|
|
* if switching to write, start write dma engine
|
|
*/
|
|
if ( ! FULL_DUPLEX(d) && (d->flags & SND_F_WRITING) )
|
|
dsp_wrintr(d) ;
|
|
DEB(printf("cannot start rd-dma rl %d fl %d\n",
|
|
b->rl, b->fl));
|
|
}
|
|
}
|
|
|
|
/*
|
|
* body of user-read routine
|
|
*
|
|
* Start DMA if not active; wait for READY not empty.
|
|
* Transfer data from READY region using uiomove(), advance boundary
|
|
* between FREE and READY. Repeat until transfer is complete.
|
|
*
|
|
* To avoid excessive latency in freeing up space for the DMA
|
|
* engine, transfers are done in blocks of increasing size, so that
|
|
* the latency is proportional to the size of the smallest block, but
|
|
* we have a low overhead and are able to feed the dma engine with
|
|
* large blocks.
|
|
*
|
|
* When we enter this routine, we assume that d->flags |= SND_F_READING
|
|
* was done before.
|
|
*
|
|
* NOTE: in the current version, read will not return more than
|
|
* blocksize bytes at once (unless more are already available), to
|
|
* avoid that requests using very large buffers block for too long.
|
|
*/
|
|
|
|
int
|
|
dsp_read_body(snddev_info *d, struct uio *buf)
|
|
{
|
|
int limit, l, n, bsz, ret = 0 ;
|
|
long s;
|
|
snd_dbuf *b = & (d->dbuf_in) ;
|
|
|
|
/*
|
|
* "limit" serves to return after at most one blocksize of data
|
|
* (unless more are already available). Otherwise, things like
|
|
* cat /dev/audio would use a 64K buffer and would start returning
|
|
* data after a _very_ long time...
|
|
* Note -- some applications depend on reads not returning short
|
|
* blocks. But I believe these apps are broken, since interrupted
|
|
* system calls might return short reads anyways, and the
|
|
* application should better check that.
|
|
*/
|
|
|
|
if (buf->uio_resid > d->rec_blocksize)
|
|
limit = buf->uio_resid - d->rec_blocksize;
|
|
else
|
|
limit = 0;
|
|
bsz = MIN_CHUNK_SIZE ; /* the current transfer (doubles at each step) */
|
|
while ( (n = buf->uio_resid) > limit ) {
|
|
DEB(printf("dsp_read_body: start waiting for %d bytes\n", n));
|
|
l = min (n, bsz);
|
|
s = spltty(); /* no interrupts here ! */
|
|
dsp_rd_dmaupdate(b);
|
|
l = min( l, b->rl ); /* no more than avail. data */
|
|
if (l == 0) {
|
|
int timeout;
|
|
/*
|
|
* If there is no data ready, then we must sleep (unless
|
|
* of course we have doing non-blocking i/o). But also
|
|
* consider restarting the DMA engine.
|
|
*/
|
|
if ( b->dl == 0 ) { /* dma was idle, start it */
|
|
if ( d->flags & SND_F_INIT && d->dbuf_out.dl == 0 ) {
|
|
/* want to init and there is no pending DMA activity */
|
|
splx(s);
|
|
d->callback(d, SND_CB_INIT); /* this is slow! */
|
|
s = spltty();
|
|
}
|
|
dsp_rdintr(d);
|
|
}
|
|
if (d->flags & SND_F_NBIO) {
|
|
splx(s);
|
|
break;
|
|
}
|
|
if (n-limit > b->dl)
|
|
timeout = hz; /* we need to wait for an int. */
|
|
else
|
|
timeout = 1; /* maybe data will be ready earlier */
|
|
ret = tsleep( (caddr_t)b, PRIBIO | PCATCH , "dsprd", timeout ) ;
|
|
if (ret == EINTR || ret == ERESTART)
|
|
d->flags |= SND_F_ABORTING ;
|
|
splx(s);
|
|
if (ret == EINTR)
|
|
break ;
|
|
continue;
|
|
}
|
|
splx(s);
|
|
|
|
/*
|
|
* Do any necessary format conversion, and copy to user space.
|
|
* NOTE: I _can_ use rp here because it is not modified by the
|
|
* interrupt routines.
|
|
*/
|
|
if (b->rp + l > b->bufsize) { /* handle wraparounds */
|
|
int l1 = b->bufsize - b->rp ;
|
|
if (d->flags & SND_F_XLAT8) {
|
|
translate_bytes(dsp_ulaw, b->buf + b->rp, l1);
|
|
translate_bytes(dsp_ulaw, b->buf , l - l1);
|
|
}
|
|
uiomove(b->buf + b->rp, l1, buf) ;
|
|
uiomove(b->buf, l - l1, buf) ;
|
|
} else {
|
|
if (d->flags & SND_F_XLAT8)
|
|
translate_bytes(dsp_ulaw, b->buf + b->rp, l);
|
|
uiomove(b->buf + b->rp, l, buf) ;
|
|
}
|
|
|
|
s = spltty(); /* no interrupts here ... */
|
|
b->fl += l ; /* this more free bytes */
|
|
b->rl -= l ; /* this less ready bytes */
|
|
b->rp += l ; /* advance ready pointer */
|
|
if (b->rp >= b->bufsize) /* handle wraps */
|
|
b->rp -= b->bufsize ;
|
|
splx(s) ;
|
|
bsz = min(b->bufsize, bsz*2);
|
|
}
|
|
s = spltty(); /* no interrupts here ... */
|
|
d->flags &= ~SND_F_READING ;
|
|
if (d->flags & SND_F_ABORTING) {
|
|
d->flags |= ~SND_F_ABORTING;
|
|
splx(s);
|
|
dsp_rdabort(d, 1 /* restart */);
|
|
/* XXX return EINTR ? */
|
|
}
|
|
splx(s) ;
|
|
return ret ;
|
|
}
|
|
|
|
|
|
/*
|
|
* short routine to initialize a dma buffer descriptor (usually
|
|
* located in the XXX_desc structure). The first parameter is
|
|
* the buffer size, the second one specifies that a 16-bit dma channel
|
|
* is used (hence the buffer must be properly aligned).
|
|
*/
|
|
void
|
|
alloc_dbuf(snd_dbuf *b, int size)
|
|
{
|
|
if (size > 0x10000)
|
|
panic("max supported size is 64k");
|
|
b->buf = contigmalloc(size, M_DEVBUF, M_NOWAIT,
|
|
0ul, 0xfffffful, 1ul, 0x10000ul);
|
|
/* should check that malloc does not fail... */
|
|
b->rp = b->fp = 0 ;
|
|
b->dl = b->rl = 0 ;
|
|
b->bufsize = b->fl = size ;
|
|
}
|
|
|
|
/*
|
|
* this resets a buffer and starts the isa dma on that channel.
|
|
* Must be called when the dma on the card is disabled (e.g. after init).
|
|
*/
|
|
void
|
|
reset_dbuf(snd_dbuf *b, int chan)
|
|
{
|
|
DEB(printf("reset dbuf for chan %d\n", b->chan));
|
|
b->rp = b->fp = 0 ;
|
|
b->dl = b->rl = 0 ;
|
|
b->fl = b->bufsize ;
|
|
if (chan == SND_CHAN_NONE)
|
|
return ;
|
|
if (chan == SND_CHAN_WR)
|
|
chan = B_WRITE | B_RAW ;
|
|
else
|
|
chan = B_READ | B_RAW ;
|
|
isa_dmastart( chan , b->buf, b->bufsize, b->chan);
|
|
}
|
|
|
|
/*
|
|
* snd_sync waits until the space in the given channel goes above
|
|
* a threshold. chan = 1 : play, 2: capture. The threshold is
|
|
* checked against fl or rl respectively.
|
|
* Assume that the condition can become true, do not check here...
|
|
*/
|
|
int
|
|
snd_sync(snddev_info *d, int chan, int threshold)
|
|
{
|
|
u_long s;
|
|
int ret;
|
|
snd_dbuf *b;
|
|
|
|
b = (chan == 1) ? &(d->dbuf_out ) : &(d->dbuf_in ) ;
|
|
|
|
for (;;) {
|
|
s=spltty();
|
|
if ( chan==1 )
|
|
dsp_wr_dmaupdate(b);
|
|
else
|
|
dsp_rd_dmaupdate(b);
|
|
if ( (chan == 1 && b->fl <= threshold) ||
|
|
(chan == 2 && b->rl <= threshold) ) {
|
|
ret = tsleep((caddr_t)b, PRIBIO|PCATCH, "sndsyn", 1);
|
|
splx(s);
|
|
if (ret == ERESTART || ret == EINTR) {
|
|
printf("tsleep returns %d\n", ret);
|
|
return -1 ;
|
|
}
|
|
} else
|
|
break;
|
|
}
|
|
splx(s);
|
|
return 0 ;
|
|
}
|
|
|
|
/*
|
|
* dsp_wrabort(d) and dsp_rdabort(d) are non-blocking functions
|
|
* which abort a pending DMA transfer and flush the buffers.
|
|
* They return the number of bytes that has not been transferred.
|
|
* The second parameter is used to restart the engine if needed.
|
|
*/
|
|
int
|
|
dsp_wrabort(snddev_info *d, int restart)
|
|
{
|
|
long s;
|
|
int missing = 0;
|
|
snd_dbuf *b = & (d->dbuf_out) ;
|
|
|
|
s = spltty();
|
|
if ( b->dl ) {
|
|
b->dl = 0 ;
|
|
d->flags &= ~ SND_F_WRITING ;
|
|
if (d->callback)
|
|
d->callback(d, SND_CB_WR | SND_CB_ABORT);
|
|
isa_dmastop(b->chan) ;
|
|
dsp_wr_dmadone(d);
|
|
|
|
DEB(printf("dsp_wrabort: stopped, %d bytes left\n", b->rl));
|
|
}
|
|
missing = b->rl;
|
|
isa_dmadone(B_WRITE, b->buf, b->bufsize, b->chan); /*free chan */
|
|
reset_dbuf(b, restart ? SND_CHAN_WR : SND_CHAN_NONE);
|
|
splx(s);
|
|
return missing;
|
|
}
|
|
|
|
int
|
|
dsp_rdabort(snddev_info *d, int restart)
|
|
{
|
|
long s;
|
|
int missing = 0;
|
|
snd_dbuf *b = & (d->dbuf_in) ;
|
|
|
|
s = spltty();
|
|
if ( b->dl ) {
|
|
b->dl = 0 ;
|
|
d->flags &= ~ SND_F_READING ;
|
|
if (d->callback)
|
|
d->callback(d, SND_CB_RD | SND_CB_ABORT);
|
|
isa_dmastop(b->chan) ;
|
|
dsp_rd_dmadone(d);
|
|
}
|
|
missing = b->rl ;
|
|
isa_dmadone(B_READ, b->buf, b->bufsize, b->chan);
|
|
reset_dbuf(b, restart ? SND_CHAN_RD : SND_CHAN_NONE);
|
|
splx(s);
|
|
return missing;
|
|
}
|
|
|
|
/*
|
|
* this routine tries to flush the dma transfer. It is called
|
|
* on a close. The caller must set SND_F_CLOSING, and insure that
|
|
* interrupts are enabled. We immediately abort any read DMA
|
|
* operation, and then wait for the play buffer to drain.
|
|
*/
|
|
|
|
int
|
|
snd_flush(snddev_info *d)
|
|
{
|
|
int ret, count=10;
|
|
u_long s;
|
|
snd_dbuf *b = &(d->dbuf_out) ;
|
|
|
|
DEB(printf("snd_flush d->flags 0x%08x\n", d->flags));
|
|
dsp_rdabort(d, 0 /* no restart */);
|
|
/* close write */
|
|
while ( b->dl ) {
|
|
/*
|
|
* still pending output data.
|
|
*/
|
|
ret = tsleep( (caddr_t)b, PRIBIO|PCATCH, "dmafl1", hz);
|
|
dsp_wr_dmaupdate(b);
|
|
DEB( printf("snd_sync: now rl : fl %d : %d\n", b->rl, b->fl ) );
|
|
if (ret == EINTR) {
|
|
printf("tsleep returns %d\n", ret);
|
|
return -1 ;
|
|
}
|
|
if ( ret && --count == 0) {
|
|
printf("timeout flushing dbuf_out.chan, cnt 0x%x flags 0x%08lx\n",
|
|
b->rl, d->flags);
|
|
break;
|
|
}
|
|
}
|
|
s = spltty(); /* should not be necessary... */
|
|
d->flags &= ~SND_F_CLOSING ;
|
|
dsp_wrabort(d, 0 /* no restart */);
|
|
splx(s);
|
|
return 0 ;
|
|
}
|
|
|
|
/*
|
|
* end of new code for dma buffer handling
|
|
*/
|