Document bus_dmamem_alloc_range(9).

1 files changed, 28 insertions, 3 deletions

diff --git a/share/man/man9/bus_dma.9 b/share/man/man9/bus_dma.9
index a77349989e8..759de6d8d86 100644
--- a/share/man/man9/bus_dma.9
+++ b/share/man/man9/bus_dma.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: bus_dma.9,v 1.32 2014/09/08 01:27:55 schwarze Exp $
+.\"	$OpenBSD: bus_dma.9,v 1.33 2015/01/24 16:06:46 kettenis Exp $
 .\" $NetBSD: bus_dma.9,v 1.14 2000/06/14 06:49:19 cgd Exp $
 .\"
 .\" Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: September 8 2014 $
+.Dd $Mdocdate: January 24 2015 $
 .Dt BUS_DMA 9
 .Os
 .Sh NAME
@@ -552,6 +552,11 @@ appropriate synchronization operations, behavior is undefined.
                      "bus_size_t alignment" "bus_size_t boundary" \
                      "bus_dma_segment_t *segs" "int nsegs" "int *rsegs" \
                      "int flags"
+.Ft int
+.Fn bus_dmamem_alloc_range "bus_dma_tag_t tag" "bus_size_t size" \
+                     "bus_size_t alignment" "bus_size_t boundary" \
+                     "bus_dma_segment_t *segs" "int nsegs" "int *rsegs" \
+                     "int flags" "bus_addr_t low" "bus_addr_t high"
 .Ft void
 .Fn bus_dmamem_free "bus_dma_tag_t tag" "bus_dma_segment_t *segs" "int nsegs"
 .nr nS 0
@@ -645,15 +650,33 @@ bus-dependent functionality.
 .El
 .El
 .Pp
+The
+.Fn bus_dmamem_alloc_range
+function is a variaton of
+.Fn bus_dmamem_alloc
+that allows specification of the "DMA safe" bus address range
+supported by the device.  The additional
+.Fa low
+and
+.Fa high
+arguments specify the lowest and highest bus address that the device
+can use for DMA transfers.
+This function should only be used if that address range differs from
+the the default address range for the bus.
+.Pp
 All pages allocated by
 .Fn bus_dmamem_alloc
+and
+.Fn bus_dmameme_alloc_range
 will be wired down until they are freed by
 .Fn bus_dmamem_free .
 .Pp
 The
 .Fn bus_dmamem_free
 function frees memory previously allocated by
-.Fn bus_dmamem_alloc ,
+.Fn bus_dmamem_alloc
+or
+.Fn bus_dmamem_alloc_range ,
 invalidating any mapping.
 This function always succeeds if given valid arguments.
 .Pp
@@ -691,6 +714,8 @@ The
 .Fn bus_dmamem_map
 function maps memory allocated with
 .Fn bus_dmamem_alloc
+or
+.Fn bus_dmamem_alloc_range
 into kernel virtual address space.
 This function returns 0 on success, an error code otherwise, and must not be
 called from an interrupt context.