Date: Mon, 18 Aug 1997 11:05:37 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: hackers@freebsd.org Subject: isa_dmastop... (fwd) Message-ID: <199708180135.LAA08486@genesis.atrad.adelaide.edu.au>
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Ok, to avoid any further agony about ISA DMA, here's a request I've had
just recently from Luigi. This looks OK to me, but again it contains the
sanity checking that Amancio was unhappy about; folks, how do you feel?
----- Forwarded message from Luigi Rizzo -----
>From luigi@labinfo.iet.unipi.it Sat Aug 9 23:27:10 1997
From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Message-Id: <199708091246.OAA01564@labinfo.iet.unipi.it>
Subject: isa_dmastop...
To: msmith@gsoft.com.au
Date: Sat, 9 Aug 1997 14:46:19 +0200 (MET DST)
X-Mailer: ELM [version 2.4 PL23]
Content-Type: text
For the sound driver to implement pause/abort, the following function
is useful (one can do things without it if tolerates some "channel
busy" messages from the kernel...) If you like it, can you commit to
isa.c ?
Thanks
Luigi
/*
* this stops the dma channel and returns the residual count
* derived calling isa_dmastatus
*/
int isa_dmastop(int chan)
{
if (dma_inuse & (1 << chan) == 0)
printf("isa_dmastop: channel %d not acquired\n", chan);
if (dma_busy & (1 << chan) == 0)
printf("isa_dmastop: channel %d not acquired\n", chan);
if ((chan & 4) == 0)
outb(DMA1_SMSK, (chan & 3) | 4 /* disable mask */);
else
outb(DMA2_SMSK, (chan & 3) | 4 /* disable mask */);
return isa_dmastatus(chan);
}
----- End of forwarded message from Luigi Rizzo -----
--
]] Mike Smith, Software Engineer msmith@gsoft.com.au [[
]] Genesis Software genesis@gsoft.com.au [[
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