diff options
| author | cinap_lenrek <cinap_lenrek@localhost> | 2011-05-18 20:02:17 +0000 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@localhost> | 2011-05-18 20:02:17 +0000 |
| commit | f5b15ebcd3edfa52a4c8eaa1ef2dd88a60196285 (patch) | |
| tree | 2ea744f217e03d6761e3035e2223032bccfe8ca9 /sys/src/9/pc/dma.c | |
| parent | df687d3840503e4811a5572bf5ce97b74cb21727 (diff) | |
dma: comment
Diffstat (limited to 'sys/src/9/pc/dma.c')
| -rw-r--r-- | sys/src/9/pc/dma.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/sys/src/9/pc/dma.c b/sys/src/9/pc/dma.c index 4a81f516a..2370442e1 100644 --- a/sys/src/9/pc/dma.c +++ b/sys/src/9/pc/dma.c @@ -212,12 +212,15 @@ dmasetup(int chan, void *va, long len, int flags) else xp->len = 0; + mode = ((flags & DMAREAD) ? 0x44 : 0x48) | /* read or write */ + ((flags & DMALOOP) ? 0x10 : 0) | /* auto init mode */ + chan; + /* * this setup must be atomic */ ilock(dp); - mode = ((flags & DMAREAD) ? 0x44 : 0x48) | ((flags & DMALOOP) ? 0x10 : 0) | chan; - outb(dp->mode, mode); /* single mode dma (give CPU a chance at mem) */ + outb(dp->mode, mode); outb(dp->page[chan], pa>>16); outb(dp->cbp, 0); /* set count & address to their first byte */ outb(dp->addr[chan], pa>>dp->shift); /* set address */ |