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Sync w/ i386 port: 

Optimize the ISA DMA map load somewhat; don't traverse the buffer twice.
Instead, just attempt to do a normal load first.  If we exceed the bounce
threshold or the number of segments, then we bounce the transfer.
This commit is contained in:
thorpej 1998-06-03 06:43:04 +00:00
parent 6ffa35b390
commit 7b37a276e2
1 changed files with 41 additions and 114 deletions
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155
sys/arch/bebox/isa/isadma_machdep.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: isadma_machdep.c,v 1.7 1998/02/12 01:19:16 sakamoto Exp $ */
/* $NetBSD: isadma_machdep.c,v 1.8 1998/06/03 06:43:04 thorpej Exp $ */
#define ISA_DMA_STATS
@ -102,7 +102,7 @@ extern vm_offset_t avail_end; /* XXX temporary */
/*
* ISA can DMA to 0-2G.
*/
#define ISA_DMA_BOUNCE_THRESHOLD 0x7fffffff
#define ISA_DMA_BOUNCE_THRESHOLD (2UL * 1024UL * 1024UL * 1024UL)
int _isa_bus_dmamap_create __P((bus_dma_tag_t, bus_size_t, int,
bus_size_t, bus_size_t, int, bus_dmamap_t *));
@ -129,8 +129,6 @@ void _isa_bus_dmamem_unmap __P((bus_dma_tag_t, caddr_t, size_t));
int _isa_bus_dmamem_mmap __P((bus_dma_tag_t, bus_dma_segment_t *,
int, int, int, int));
int _isa_dma_check_buffer __P((void *, bus_size_t, int, bus_size_t,
struct proc *));
int _isa_dma_alloc_bouncebuf __P((bus_dma_tag_t, bus_dmamap_t,
bus_size_t, int));
void _isa_dma_free_bouncebuf __P((bus_dma_tag_t, bus_dmamap_t));
@ -141,6 +139,7 @@ void _isa_dma_free_bouncebuf __P((bus_dma_tag_t, bus_dmamap_t));
* buffers, if necessary.
*/
struct bebox_bus_dma_tag isa_bus_dma_tag = {
ISA_DMA_BOUNCE_THRESHOLD,
NULL, /* _cookie */
_isa_bus_dmamap_create,
_isa_bus_dmamap_destroy,
@ -314,58 +313,50 @@ _isa_bus_dmamap_load(t, map, buf, buflen, p, flags)
map->dm_nsegs = 0;
/*
* Check to see if we might need to bounce the transfer.
* Try to load the map the normal way. If this errors out,
* and we can bounce, we will.
*/
if (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) {
/*
* Check if all pages are below the bounce
* threshold. If they are, don't bother bouncing.
*/
if (_isa_dma_check_buffer(buf, buflen,
map->_dm_segcnt, map->_dm_boundary, p) == 0)
return (_bus_dmamap_load(t, map, buf, buflen,
p, flags));
error = _bus_dmamap_load(t, map, buf, buflen, p, flags);
if (error == 0 ||
(error != 0 && (cookie->id_flags & ID_MIGHT_NEED_BOUNCE) == 0))
return (error);
STAT_INCR(isa_dma_stats_bounces);
/*
* First attempt failed; bounce it.
*/
/*
* Allocate bounce pages, if necessary.
*/
if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
error = _isa_dma_alloc_bouncebuf(t, map, buflen,
flags);
if (error)
return (error);
}
STAT_INCR(isa_dma_stats_bounces);
/*
* Cache a pointer to the caller's buffer and
* load the DMA map with the bounce buffer.
*/
cookie->id_origbuf = buf;
cookie->id_origbuflen = buflen;
error = _bus_dmamap_load(t, map, cookie->id_bouncebuf,
buflen, p, flags);
if (error) {
/*
* Free the bounce pages, unless our resources
* are reserved for our exclusive use.
*/
if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
_isa_dma_free_bouncebuf(t, map);
}
/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
cookie->id_flags |= ID_IS_BOUNCING;
} else {
/*
* Just use the generic load function.
*/
error = _bus_dmamap_load(t, map, buf, buflen, p, flags);
/*
* Allocate bounce pages, if necessary.
*/
if ((cookie->id_flags & ID_HAS_BOUNCE) == 0) {
error = _isa_dma_alloc_bouncebuf(t, map, buflen, flags);
if (error)
return (error);
}
return (error);
/*
* Cache a pointer to the caller's buffer and load the DMA map
* with the bounce buffer.
*/
cookie->id_origbuf = buf;
cookie->id_origbuflen = buflen;
error = _bus_dmamap_load(t, map, cookie->id_bouncebuf, buflen,
p, flags);
if (error) {
/*
* Free the bounce pages, unless our resources
* are reserved for our exclusive use.
*/
if ((map->_dm_flags & BUS_DMA_ALLOCNOW) == 0)
_isa_dma_free_bouncebuf(t, map);
return (error);
}
/* ...so _isa_bus_dmamap_sync() knows we're bouncing */
cookie->id_flags |= ID_IS_BOUNCING;
return (0);
}
/*
@ -583,70 +574,6 @@ _isa_bus_dmamem_mmap(t, segs, nsegs, off, prot, flags)
* ISA DMA utility functions
**********************************************************************/
/*
* Return 0 if all pages in the passed buffer lie within the DMA'able
* range RAM.
*/
int
_isa_dma_check_buffer(buf, buflen, segcnt, boundary, p)
void *buf;
bus_size_t buflen;
int segcnt;
bus_size_t boundary;
struct proc *p;
{
vm_offset_t vaddr = (vm_offset_t)buf;
vm_offset_t pa, lastpa, endva;
u_long pagemask = ~(boundary - 1);
pmap_t pmap;
int nsegs;
endva = round_page(vaddr + buflen);
nsegs = 1;
lastpa = 0;
if (p != NULL)
pmap = p->p_vmspace->vm_map.pmap;
else
pmap = pmap_kernel();
for (; vaddr < endva; vaddr += NBPG) {
/*
* Get physical address for this segment.
*/
pa = pmap_extract(pmap, (vm_offset_t)vaddr);
pa = trunc_page(pa);
/*
* Is it below the DMA'able threshold?
*/
if (pa > ISA_DMA_BOUNCE_THRESHOLD)
return (EINVAL);
if (lastpa) {
/*
* Check excessive segment count.
*/
if (lastpa + NBPG != pa) {
if (++nsegs > segcnt)
return (EFBIG);
}
/*
* Check boundary restriction.
*/
if (boundary) {
if ((lastpa ^ pa) & pagemask)
return (EINVAL);
}
}
lastpa = pa;
}
return (0);
}
int
_isa_dma_alloc_bouncebuf(t, map, size, flags)
bus_dma_tag_t t;