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Add handling of DMA boundary barrier in _bus_dmamap_load_buffer(). This 

affects all bus_dmamap_load* functions of bus_dma(9).
While I'm there fix a bug where the dm_segs array could be overflowded by one.
This commit is contained in:
bouyer 1998-05-29 16:48:09 +00:00
parent 34b0df807a
commit 94d805aff1
1 changed files with 16 additions and 4 deletions
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20
sys/arch/i386/i386/machdep.c
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@ -1,4 +1,4 @@
/* $NetBSD: machdep.c,v 1.303 1998/05/28 16:56:26 drochner Exp $ */
/* $NetBSD: machdep.c,v 1.304 1998/05/29 16:48:09 bouyer Exp $ */
/*-
* Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
@ -2888,7 +2888,7 @@ _bus_dmamap_load_buffer(map, buf, buflen, p, flags, lastaddrp, segp, first)
int first;
{
bus_size_t sgsize;
bus_addr_t curaddr, lastaddr;
bus_addr_t curaddr, lastaddr, baddr, bmask;
caddr_t vaddr = buf;
int seg;
pmap_t pmap;
@ -2899,8 +2899,9 @@ _bus_dmamap_load_buffer(map, buf, buflen, p, flags, lastaddrp, segp, first)
pmap = pmap_kernel();
lastaddr = *lastaddrp;
bmask = ~(map->_dm_boundary - 1);
for (seg = *segp; buflen > 0 && seg < map->_dm_segcnt; ) {
for (seg = *segp; buflen > 0 ; ) {
/*
* Get the physical address for this segment.
*/
@ -2912,6 +2913,12 @@ _bus_dmamap_load_buffer(map, buf, buflen, p, flags, lastaddrp, segp, first)
sgsize = NBPG - ((u_long)vaddr & PGOFSET);
if (buflen < sgsize)
sgsize = buflen;
/* If needed, compute upper boundary line and adjust seg size */
if (map->_dm_boundary > 0) {
baddr = ((u_long)curaddr + map->_dm_boundary) & bmask;
if (sgsize > (baddr - curaddr))
sgsize = (baddr - curaddr);
}
/*
* Insert chunk into a segment, coalescing with
@ -2924,10 +2931,15 @@ _bus_dmamap_load_buffer(map, buf, buflen, p, flags, lastaddrp, segp, first)
} else {
if (curaddr == lastaddr &&
(map->dm_segs[seg].ds_len + sgsize) <=
map->_dm_maxsegsz)
map->_dm_maxsegsz &&
(map->_dm_boundary == 0 ||
(map->dm_segs[seg].ds_addr & bmask) ==
(curaddr & bmask)))
map->dm_segs[seg].ds_len += sgsize;
else {
seg++;
if (seg >= map->_dm_segcnt)
break;
map->dm_segs[seg].ds_addr = curaddr;
map->dm_segs[seg].ds_len = sgsize;
}