[src/trunk]: src/sys/arch/mips/mips mmap() DMA buffers uncached if we know how.

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

details:   https://anonhg.NetBSD.org/src/rev/77d23ee3b2c1
branches:  trunk
changeset: 336194:77d23ee3b2c1
user:      macallan <macallan%NetBSD.org@localhost>
date:      Mon Feb 16 14:10:00 2015 +0000

description:
mmap() DMA buffers uncached if we know how.
>From sgimips, needed for X on O2.

diffstat:

 sys/arch/mips/mips/bus_dma.c |  13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diffs (35 lines):

diff -r 5721b720b871 -r 77d23ee3b2c1 sys/arch/mips/mips/bus_dma.c
--- a/sys/arch/mips/mips/bus_dma.c      Mon Feb 16 13:33:24 2015 +0000
+++ b/sys/arch/mips/mips/bus_dma.c      Mon Feb 16 14:10:00 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: bus_dma.c,v 1.32 2015/02/13 17:19:23 skrll Exp $       */
+/*     $NetBSD: bus_dma.c,v 1.33 2015/02/16 14:10:00 macallan Exp $    */
 
 /*-
  * Copyright (c) 1997, 1998, 2001 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.32 2015/02/13 17:19:23 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bus_dma.c,v 1.33 2015/02/16 14:10:00 macallan Exp $");
 
 #define _MIPS_BUS_DMA_PRIVATE
 
@@ -1162,7 +1162,16 @@
 
                pa = (paddr_t)segs[i].ds_addr + off;
 
+/*
+ * This is for machines which use normal RAM as video memory, so userland can
+ * mmap() it and treat it like device memory, which is normally uncached.
+ * Needed for X11 on SGI O2, will likely be needed on things like CI20.
+ */
+#if defined(_MIPS_PADDR_T_64BIT) || defined(_LP64)
+               return (mips_btop(pa | PGC_NOCACHE));
+#else
                return mips_btop(pa);
+#endif
        }
 
        /* Page not found. */