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If mapping only one segment of DMA memory into KVA space, use K0SEG.

This commit is contained in:
thorpej 1998-01-19 03:12:20 +00:00
parent 5f78a36791
commit 12809e3434
1 changed files with 19 additions and 3 deletions
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22
sys/arch/alpha/common/bus_dma.c
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@ -1,7 +1,7 @@
/* $NetBSD: bus_dma.c,v 1.7 1998/01/09 06:37:04 thorpej Exp $ */
/* $NetBSD: bus_dma.c,v 1.8 1998/01/19 03:12:20 thorpej Exp $ */
/*-
* Copyright (c) 1997 The NetBSD Foundation, Inc.
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@ -39,7 +39,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.7 1998/01/09 06:37:04 thorpej Exp $");
__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.8 1998/01/19 03:12:20 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -402,6 +402,15 @@ _bus_dmamem_map(t, segs, nsegs, size, kvap, flags)
bus_addr_t addr;
int curseg, s;
/*
* If we're only mapping 1 segment, use K0SEG, to avoid
* TLB thrashing.
*/
if (nsegs == 1) {
*kvap = (caddr_t)ALPHA_PHYS_TO_K0SEG(segs[0].ds_addr);
return (0);
}
size = round_page(size);
s = splimp();
@ -448,6 +457,13 @@ _bus_dmamem_unmap(t, kva, size)
panic("_bus_dmamem_unmap");
#endif
/*
* Nothing to do if we mapped it with K0SEG.
*/
if (kva >= (caddr_t)ALPHA_K0SEG_BASE &&
kva <= (caddr_t)ALPHA_K0SEG_END)
return;
size = round_page(size);
s = splimp();
kmem_free(kmem_map, (vm_offset_t)kva, size);