[src/trunk]: src/sys/arch/powerpc/powerpc A small speedup, when mapping memor...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c66dc45dfbab
branches:  trunk
changeset: 765870:c66dc45dfbab
user:      matt <matt%NetBSD.org@localhost>
date:      Wed Jun 08 15:19:57 2011 +0000

description:
A small speedup, when mapping memory in bus_dmamem_map, if the memory is
cacheable and is in a single segment (physically contiguous) don't bother
allocating KVA for it, just use the physical address as the VA.

diffstat:

 sys/arch/powerpc/powerpc/bus_dma.c |  29 ++++++++++++++++++++++-------
 1 files changed, 22 insertions(+), 7 deletions(-)

diffs (62 lines):

diff -r 8b9fd94bc833 -r c66dc45dfbab sys/arch/powerpc/powerpc/bus_dma.c
--- a/sys/arch/powerpc/powerpc/bus_dma.c        Wed Jun 08 13:54:16 2011 +0000
+++ b/sys/arch/powerpc/powerpc/bus_dma.c        Wed Jun 08 15:19:57 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bus_dma.c,v 1.38 2011/01/18 01:02:55 matt Exp $        */
+/*     $NetBSD: bus_dma.c,v 1.39 2011/06/08 15:19:57 matt Exp $        */
 
 /*-
  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
 
 #define _POWERPC_BUS_DMA_PRIVATE
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.38 2011/01/18 01:02:55 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.39 2011/06/08 15:19:57 matt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -601,6 +601,19 @@
 
        size = round_page(size);
 
+#ifdef PMAP_MAP_POOLPAGE
+       /*
+        * If we are mapping a cacheable physically contiguous segment, treat
+        * it as if we are mapping a poolpage and avoid consuming any KVAs.
+        */
+       if (nsegs == 1 && (flags & BUS_DMA_NOCACHE) == 0) {
+               KASSERT(size == segs->ds_len);
+               addr = BUS_MEM_TO_PHYS(t, segs->ds_addr);
+               *kvap = (void *)PMAP_MAP_POOLPAGE(addr);
+               return 0;
+       }
+#endif
+
        va = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_VAONLY | kmflags);
 
        if (va == 0)
@@ -639,16 +652,18 @@
 void
 _bus_dmamem_unmap(bus_dma_tag_t t, void *kva, size_t size)
 {
+       vaddr_t va = (vaddr_t) kva;
 
 #ifdef DIAGNOSTIC
-       if ((u_long)kva & PGOFSET)
+       if (va & PGOFSET)
                panic("_bus_dmamem_unmap");
 #endif
 
-       size = round_page(size);
-
-       pmap_kremove((vaddr_t)kva, size);
-       uvm_km_free(kernel_map, (vaddr_t)kva, size, UVM_KMF_VAONLY);
+       if (va >= VM_MIN_KERNEL_ADDRESS && va < VM_MAX_KERNEL_ADDRESS) {
+               size = round_page(size);
+               pmap_kremove(va, size);
+               uvm_km_free(kernel_map, va, size, UVM_KMF_VAONLY);
+       }
 }
 
 /*