REVERT TO PREVIOUS STATE OF AFFAIR.

If those pages are different from the NetBSD version, maybe there's a
reason ?

Like, possibly, I just read our source code, which just happens to do
things in DIFFERENT ways than NetBSD does ?

As far as the added pages go, they obviously haven't been checked against
actual code as well, hence they're worse than useless, since a large part
of the information is definitely misleading.

1 files changed, 0 insertions, 673 deletions

diff --git a/share/man/man9/bus_dma.9 b/share/man/man9/bus_dma.9
deleted file mode 100644
index 77f53340090..00000000000
--- a/share/man/man9/bus_dma.9
+++ /dev/null
@@ -1,673 +0,0 @@
-.\"	$OpenBSD: bus_dma.9,v 1.1 1999/09/22 03:16:47 csapuntz Exp $
-.\"	$NetBSD: bus_dma.9,v 1.11 1999/03/16 00:40:47 garbled Exp $
-.\"
-.\" Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
-.\" All rights reserved.
-.\" 
-.\" This code is derived from software contributed to The NetBSD Foundation
-.\" by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
-.\" NASA Ames Research Center.
-.\" 
-.\" Redistribution and use in source and binary forms, with or without
-.\" modification, are permitted provided that the following conditions
-.\" are met:
-.\" 1. Redistributions of source code must retain the above copyright
-.\"    notice, this list of conditions and the following disclaimer.
-.\" 2. Redistributions in binary form must reproduce the above copyright
-.\"    notice, this list of conditions and the following disclaimer in the
-.\"    documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\"    must display the following acknowledgment:
-.\" 	This product includes software developed by the NetBSD
-.\" 	Foundation, Inc. and its contributors.
-.\" 4. Neither the name of The NetBSD Foundation nor the names of its
-.\"    contributors may be used to endorse or promote products derived
-.\"    from this software without specific prior written permission.
-.\" 
-.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
-.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
-.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
-.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
-.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
-.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
-.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
-.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
-.\" POSSIBILITY OF SUCH DAMAGE.
-.\"
-.Dd February 3, 1998
-.Dt BUS_DMA 9
-.Os
-.Sh NAME
-.Nm bus_dma ,
-.Nm bus_dmamap_create ,
-.Nm bus_dmamap_destroy ,
-.Nm bus_dmamap_load ,
-.Nm bus_dmamap_load_mbuf ,
-.Nm bus_dmamap_load_uio ,
-.Nm bus_dmamap_load_raw ,
-.Nm bus_dmamap_unload ,
-.Nm bus_dmamap_sync ,
-.Nm bus_dmamem_alloc ,
-.Nm bus_dmamem_free ,
-.Nm bus_dmamem_map ,
-.Nm bus_dmamem_unmap ,
-.Nm bus_dmamem_mmap
-.Nd Bus and Machine Independent DMA Mapping Interface
-.Sh SYNOPSIS
-.Fd #include <machine/bus.h>
-.Ft int
-.Fn bus_dmamap_create "bus_dma_tag_t tag" "bus_size_t size" "int nsegments" \
-"bus_size_t maxsegsz" "bus_size_t boundary" "int flags" "bus_dmamap_t *dmamp"
-.Ft void
-.Fn bus_dmamap_destroy "bus_dma_tag_t tag" "bus_dmamap_t dmam"
-.Ft int
-.Fn bus_dmamap_load "bus_dma_tag_t tag" "bus_dmamap_t dmam" "void *buf" \
-"bus_size_t buflen" "struct proc *p" "int flags"
-.Ft int
-.Fn bus_dmamap_load_mbuf "bus_dma_tag_t tag" "bus_dmamap_t dmam" \
-"struct mbuf *chain" "int flags"
-.Ft int
-.Fn bus_dmamap_load_uio "bus_dma_tag_t tag" "bus_dmamap_t dmam" \
-"struct uio *uio" "int flags"
-.Ft int
-.Fn bus_dmamap_load_raw "bus_dma_tag_t tag" "bus_dmamap_t dmam" \
-"bus_dma_segment_t *segs" "int nsegs" "bus_size_t size" "int flags"
-.Ft void
-.Fn bus_dmamap_unload "bus_dma_tag_t tag" "bus_dmamap_t dmam"
-.Ft void
-.Fn bus_dmamap_sync "bus_dma_tag_t tag" "bus_dmamap_t dmam" \
-"bus_addr_t offset" "bus_size_t len" "int ops"
-.Ft int
-.Fn bus_dmamem_alloc "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"
-.Ft void
-.Fn bus_dmamem_free "bus_dma_tag_t tag" "bus_dma_segment_t *segs" "int nsegs"
-.Ft int
-.Fn bus_dmamem_map "bus_dma_tag_t tag" "bus_dma_segment_t *segs" "int nsegs" \
-"size_t size" "caddr_t *kvap" "int flags"
-.Ft void
-.Fn bus_dmamem_unmap "bus_dma_tag_t tag" "caddr_t kva" "size_t size"
-.Ft int
-.Fn bus_dmamem_mmap "bus_dma_tag_t tag" "bus_dma_segment_t *segs" \
-"int nsegs" "int off" "int prot" "int flags"
-.Sh DESCRIPTION
-Provide a bus- and machine-independent "DMA mapping interface."
-.Sh NOTES
-.Pp
-All data structures, function prototypes, and macros will be defined
-by the port-specific header
-.Pa Aq machine/bus.h .
-Note that this document
-assumes the existence of types already defined by the current "bus.h"
-interface.
-.Pp
-Unless otherwise noted, all function calls in this interface may be
-defined as
-.Xr cpp 1
-macros.
-.Sh DATA TYPES
-.Pp
-Individual implementations may name these structures whatever they
-wish, providing that the external representations are:
-.Bl -tag -width compact
-.It Fa bus_dma_tag_t
-A machine-dependent opaque type describing the implementation of
-DMA for a given bus.
-.It Fa bus_dma_segment_t
-A structure with at least the following members:
-.Bd -literal
-	bus_addr_t	ds_addr;
-	bus_size_t	ds_len;
-.Ed
-.sp
-The structure may have machine-dependent members and arbitrary layout.
-The values in
-.Fa ds_addr
-and
-.Fa ds_len
-are suitable for programming into
-DMA controller address and length registers.
-.It Fa bus_dmamap_t
-A pointer to a structure with at least the following members:
-.Bd -literal
-	bus_size_t	dm_mapsize;
-	int		dm_nsegs;
-	bus_dma_segment_t *dm_segs;
-.Ed
-.sp
-The structure may have machine-dependent members and arbitrary layout.
-The
-.Fa dm_mapsize
-member indicates the size of the mapping.  A value of 0 indicates the
-mapping is invalid.
-The
-.Fa dm_segs
-member may be an array of segments or a pointer to an
-array of segments.  The
-.Fa dm_nsegs
-member indicates the number of segments in
-.Fa dm_segs .
-.El
-.Sh FUNCTIONS
-.Bl -tag -width compact
-.It Fn bus_dmamap_create "tag" "size" "nsegments" "maxsegsz" "boundary" "flags" "dmamp"
-Allocates a DMA handle and initializes it according to the parameters
-provided.
-Arguments are as follows:
-.Bl -tag -width nsegments -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa size
-This is the maximum DMA transfer that can be mapped by the handle.
-.It Fa nsegments
-Number of segments the device can support in a single DMA transaction.
-This may be the number of scatter-gather descriptors supported by the
-device.
-.It Fa maxsegsz
-The maximum number of bytes that may be transferred by any given DMA
-segment.
-.It Fa boundary
-Some DMA controllers are not able to transfer data that crosses a
-particular boundary.  This argument allows this boundary to be
-specified.  The boundary lines begin at 0, and occur every
-.Fa boundary
-bytes.  Mappings may begin on a boundary line but may not end on or
-cross a boundary line.  If no boundary condition needs to be observed, a
-.Fa boundary
-argument of 0 should be used.
-.It Fa flags
-Flags are defined as follows:
-.Bl -tag -width BUS_DMA_ALLOCNOW -compact
-.It Dv BUS_DMA_WAITOK
-It is safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_NOWAIT
-It is not safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_ALLOCNOW
-Perform any resource allocation this handle may need now.  If this is
-not specified, the allocation may be deferred to
-.Fn bus_dmamap_load .
-If this flag is specified,
-.Fn bus_dmamap_load
-will not block on resource
-allocation.
-.It Dv BUS_DMA_BUS[1-4]
-These flags are placeholders, and may be used by busses to provide
-bus-dependent functionality.
-.El
-.It Fa dmamp
-This is a pointer to a bus_dmamap_t.  A DMA map will be allocated and
-pointed to by 
-.Fa dmamp
-upon successful completion of this routine.
-.El
-.Pp
-Behavior is not defined if invalid arguments are passed to
-.Fn bus_dmamap_create .
-.Pp
-Returns 0 on success, or an error code to indicate mode of failure.
-.It Fn bus_dmamap_destroy "tag" "dmam"
-Frees all resources associated with a given DMA handle.  Arguments are
-as follows:
-.Bl -tag -width dmam -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa dmam
-The DMA handle to destroy.
-.El
-.Pp
-In the event that the DMA handle contains a valid mapping,
-the mapping will be unloaded via the same mechanism used by 
-.Fn bus_dmamap_unload .
-.Pp
-Behavior is not defined if invalid arguments are passed to
-.Fn bus_dmamap_destroy .
-.Pp
-If given valid arguments,
-.Fn bus_dmamap_destroy
-always succeeds.
-.It Fn bus_dmamap_load "tag" "dmam" "buf" "buflen" "p" "flags"
-Loads a DMA handle with mappings for a DMA transfer.  It assumes that
-all pages involved in a DMA transfer are wired.
-Arguments are as follows:
-.Bl -tag -width buflen -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa dmam
-The DMA handle with which to map the transfer.
-.It Fa buf
-The buffer to be used for the DMA transfer.
-.It Fa buflen
-The size of the buffer.
-.It Fa p
-Used to indicate the address space in which the buffer is located.  If
-.Dv NULL ,
-the buffer is assumed to be in kernel space.  Otherwise, the
-buffer is assumed to be in process
-.Fa p Ns 's
-address space.
-.It Fa flags
-are defined as follows:
-.Bl -tag -width "BUS_DMA_BUS[1-4]" -compact
-.It Dv BUS_DMA_WAITOK
-It is safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_NOWAIT
-It is not safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_BUS[1-4]
-These flags are placeholders, and may be used by busses to
-provide bus-dependent functionality.
-.El
-.El
-.Pp
-As noted above, if a DMA handle is created with
-.Dv BUS_DMA_ALLOCNOW ,
-.Fn bus_dmamap_load
-will never block.
-.Pp
-If a call to 
-.Fn bus_dmamap_load
-fails, the mapping in
-the DMA handle will be invalid.  It is the responsibility
-of the caller to clean up any inconsistent device state
-resulting from incomplete iteration through the uio.
-.Pp
-Behavior is not defined if invalid arguments are passed to
-.Fn bus_dmamap_load .
-.Pp
-Returns 0 on success, or an error code to indicate mode of failure.
-.It Fn bus_dmamap_load_mbuf "tag" "dmam" "chain" "flags"
-This is a variation of 
-.Fn bus_dmamap_load
-which maps mbuf chains
-for DMA transfers.  Mbuf chains are assumed to be in kernel
-virtual address space.
-.It Fn bus_dmamap_load_uio "tag" "dmam" "uio" "flags"
-This is a variation of
-.Fn bus_dmamap_load
-which maps buffers pointed to by
-.Fa uio
-for DMA transfers.  The value of
-.Fa "uio->uio_segflg"
-will
-determine if the buffers are in user or kernel virtual address space.
-If the buffers are in user address space, the buffers are assumed to be
-in
-.Fa "uio->uio_procp" Ns 's
-address space.
-.It Fn bus_dmamap_load_raw "tag" "dmam" "segs" "nsegs" "size" "flags"
-This is a variation of
-.Fn bus_dmamap_load
-which maps buffers
-allocated by
-.Fn bus_dmamem_alloc
-(see below).  The
-.Fa segs
-argument is an array of bus_dma_segment_t's filled in
-by
-.Fn bus_dmamem_alloc .
-The
-.Fa nsegs
-argument is the number of segments in the array.  The
-.Fa size
-argument is the size of the DMA transfer.
-.It Fn bus_dmamap_unload "tag" "dmam"
-Deletes the mappings for a given DMA handle.  Arguments are as follows:
-.Bl -tag -width dmam -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa dmam
-The DMA handle containing the mappings which are to be deleted.
-.El
-.Pp
-If the DMA handle was created with
-.Dv BUS_DMA_ALLOCNOW ,
-.Fn bus_dmamap_unload
-will not free the corresponding
-resources which were allocated by
-.Fn bus_dmamap_create .
-This is to ensure that
-.Fn bus_dmamap_load
-will never block
-on resources if the handle was created with
-.Dv BUS_DMA_ALLOCNOW .
-.Pp
-Behavior is not defined if invalid arguments are passed to
-.Fn bus_dmamap_unload .
-.Pp
-If given valid arguments,
-.Fn bus_dmamap_unload
-always succeeds.
-.It Fn bus_dmamap_sync "tag" "dmam" "offset" "len" "ops"
-Performs pre- and post-DMA operation cache and/or buffer synchronization.
-Arguments are as follows:
-.Bl -tag -width offset -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa dmam
-The DMA mapping to be synchronized.
-.It Fa offset
-The offset into the DMA mapping to synchronize.
-.It Fa len
-The length of the mapping from
-.Fa offset
-to synchronize.
-.It Fa ops
-One or more synchronization operation to perform.  The following DMA
-synchronization operations are defined:
-.Bl -tag -width BUS_DMASYNC_POSTWRITE -compact
-.It Dv BUS_DMASYNC_PREREAD
-Perform any pre-read DMA cache and/or bounce operations.
-.It Dv BUS_DMASYNC_POSTREAD
-Perform any post-read DMA cache and/or bounce operations.
-.It Dv BUS_DMASYNC_PREWRITE
-Perform any pre-write DMA cache and/or bounce operations.
-.It Dv BUS_DMASYNC_POSTWRITE
-Perform any post-write DMA cache and/or bounce operations.
-.El
-.Pp
-More than one operation may performed in a given synchronization call.
-Mixing of
-.Em PRE
-and
-.Em POST
-operations is not allowed, and behavior is undefined if this is attempted.
-.El
-.Pp
-Synchronization operations are expressed from the perspective of
-the host RAM, e.g. a
-.Em "device -> memory"
-operation is a
-.Em READ
-and a
-.Em "memory -> device"
-operation is a
-.Em WRITE .
-.Pp
-.Fn bus_dmamp_sync
-may consult state kept within the DMA map to determine if the memory
-is mapped in a DMA coherent fashion.  If so,
-.Fn bus_dmamap_sync
-may elect to skip certain expensive operations, such as flushing
-of the data cache.  See
-.Fn bus_dmamem_map
-for more information on this subject.
-.Pp
-On platforms which implement reordered stores,
-.Fn bus_dmamap_sync
-will always cause the store buffer to be flushed.
-.Pp
-This function exists so that multiple read and write transfers can be
-performed with the same buffer, and so that drivers can explicitly
-inform the
-.Nm 
-code when their data is 'ready' in its DMA buffer.
-.Pp
-An example of multiple read-write use of a single mapping
-might look like:
-.Bd -literal
-bus_dmamap_load(...);
-
-while (not done) {
-	/* invalidate soon-to-be-stale cache blocks */
-	bus_dmamap_sync(..., BUS_DMASYNC_PREREAD);
-
-	[ do read DMA ]
-
-	/* copy from bounce */
-	bus_dmamap_sync(..., BUS_DMASYNC_POSTREAD);
-
-	/* read data now in driver-provided buffer */
-
-	[ computation ]
-
-	/* data to be written now in driver-provided buffer */
-
-	/* flush write buffers and writeback, copy to bounce */
-	bus_dmamap_sync(..., BUS_DMASYNC_PREWRITE);
-
-	[ do write DMA ]
-
-	/* probably a no-op, but provided for consistency */
-	bus_dmamap_sync(..., BUS_DMASYNC_POSTWRITE);
-}
-
-bus_dmamap_unload(...);
-.Ed
-.Pp
-If DMA read and write operations are not preceded and followed by the
-appropriate synchronization operations, behavior is undefined.
-.Pp
-Behavior is not defined if invalid arguments are passed to
-.Fn bus_dmamap_sync .
-.Pp
-If given valid arguments,
-.Fn bus_dmamap_sync
-always succeeds.
-.\" XXX: This does not work with all the arguments.
-.It Fn bus_dmamem_alloc "tag" "size" "alignment" "boundary" "segs" "..."
-Allocates memory that is "DMA safe" for the bus corresponding to the
-given tag.  The mapping of this memory is machine-dependent (or
-"opaque"); machine-independent code is not to assume that the
-addresses returned are valid in kernel virtual address space, or that
-the addresses returned are system physical addresses.
-.Pp
-Allocations will always be rounded to the hardware page size.  Callers
-may wish to take advantage of this, and cluster allocation of small
-data structures.
-Arguments are as follows:
-.Bl -tag -width alignment -compact
-.It Fa tag
-The is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa size
-The amount of memory to allocate.
-.It Fa alignment
-Each segment in the allocated memory will be aligned to this value.  If
-the alignment is less than a hardware page size, it will be rounded up
-to the hardware page size.  This value must be a power of two.
-.It Fa boundary
-Each segment in the allocated memory must not cross this boundary
-(relative to zero).  This value must be a power of two.  A boundary
-value less than the size of the allocation is invalid.
-.It Fa segs
-An array of bus_dma_segment_t's, filled in as memory is allocated,
-representing the opaque addresses of the memory chunks.
-.It Fa nsegs
-Specifies the number of segments in
-.Fa segs ,
-and this is the maximum number
-of segments that the allocated memory may contain.
-.It Fa rsegs
-Used to return the actual number of segments the memory contains.
-.It Fa flags
-Flags are defined as follows:
-.Bl -tag -width BUS_DMA_BUS[1-4] -compact
-.It Dv BUS_DMA_WAITOK
-It is safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_NOWAIT
-It is not safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_BUS[1-4]
-These flags are placeholders, and may be used by busses to provide
-bus-dependent functionality.
-.El
-.El
-.Pp
-All pages allocated by
-.Fn bus_dmamem_alloc
-will be wired down
-until they are freed by
-.Fn bus_dmamem_free .
-.Pp
-Behavior is undefined if invalid arguments are passed to
-.Fn bus_dmamem_alloc .
-.Pp
-Returns 0 on success, or an error code indicating mode of failure.
-.It Fn bus_dmamem_free "tag" "segs" "nsegs"
-Frees memory previously allocated by 
-.Fn bus_dmamem_alloc .
-Any mappings
-will be invalidated.  Arguments are as follows:
-.Bl -tag -width nsegs -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa segs
-The array of bus_dma_segment_t's filled in by
-.Fn bus_dmamem_alloc .
-.It Fa nsegs
-The number of segments in
-.Fa segs .
-.El
-.Pp
-Behavior is undefined if invalid arguments are passed to
-.Fn bus_dmamem_free .
-.Pp
-If given valid arguments, 
-.Fn bus_dmamem_free
-always succeeds.
-.It Fn bus_dmamem_map "tag" "segs" "nsegs" "size" "kvap" "flags"
-Maps memory allocated with
-.Fn bus_dmamem_alloc
-into kernel virtual address space.  Arguments are as follows:
-.Bl -tag -width flags -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa segs
-The array of bus_dma_segment_t's filled in by
-.Fn bus_dmamem_alloc ,
-representing the memory regions to map.
-.It Fa nsegs
-The number of segments in
-.Fa segs .
-.It Fa size
-The size of the mapping.
-.It Fa kvap
-Filled in to specify the kernel virtual address where the memory is mapped.
-.It Fa flags
-Flags are defined as follows:
-.Bl -tag -width BUS_DMA_COHERENT -compact
-.It Dv BUS_DMA_WAITOK
-It is safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_NOWAIT
-It is not safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_BUS[1-4]
-These flags are placeholders, and may be used by busses to provide
-bus-dependent functionality.
-.It Dv BUS_DMA_COHERENT
-This flag is a
-.Em hint
-to machine-dependent code.  If possible, map the memory in such a way
-as it will be DMA coherent.  This may include mapping the pages into
-uncached address space or setting the cache-inhibit bits in page table
-entries.  If implementation of DMA coherent mappings is impossible, this
-is ignored.
-.Pp
-Later, when this memory is loaded into a DMA map, machine-dependent code
-will take whatever steps are necessary to determine if the memory was
-mapped in a DMA coherent fashion.  This may include checking if the
-kernel virtual address lies within uncached address space or if the
-cache-inhibit bits are set in page table entries.  If it is determined
-that the mapping is DMA coherent, state may be placed into the DMA map
-for use by later calls to
-.Fn bus_dmamap_sync .
-.El
-.El
-.Pp
-Behavior is undefined if invalid arguments are passed to
-.Fn bus_dmamem_map .
-.Pp
-Returns 0 on success, or an error code indicating mode of failure.
-.It Fn bus_dmamem_unmap "tag" "kva" "size"
-Unmaps memory previously mapped with
-.Fn bus_dmamem_map ,
-freeing the
-kernel virtual address space used by the mapping.  The arguments are as
-follows:
-.Bl -tag -width size -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa kva
-The kernel virtual address of the mapped memory.
-.It Fa size
-The size of the mapping.
-.El
-.Pp
-Behavior is undefined if invalid arguments are passed to
-.Fn bus_dmamem_unmap .
-.Pp
-If given valid arguments, 
-.Fn bus_dmamem_unmap
-always succeeds.
-.It Fn bus_dmamem_mmap "tag" "segs" "nsegs" "off" "prot" "flags"
-Provides support for user
-.Xr mmap 2 Ns 'ing
-of DMA-safe memory.  This function is to be called by a device
-driver's (*d_mmap)() entry point, which is called by the
-device pager for each page to be mapped.  The arguments are
-as follows:
-.Bl -tag -width nsegs -compact
-.It Fa tag
-This is the bus_dma_tag_t passed down from the parent driver via
-.Fa <bus>_attach_args .
-.It Fa segs
-The array of bus_dma_segment_t's filled in by
-.Fn bus_dmamem_alloc ,
-representing the memory to be
-.Xr mmap 2 Ns 'ed.
-.It Fa nsegs
-The number of elements in the
-.Fa segs
-array.
-.It Fa off
-The offset of the page in DMA memory which is to be mapped.
-.It Fa prot
-The protection codes for the mapping.
-.It Fa flags
-Flags are defined as follows:
-.Bl -tag -width BUS_DMA_COHERENT -compact
-.It Dv BUS_DMA_WAITOK
-It is safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_NOWAIT
-It is not safe to wait (sleep) for resources during this call.
-.It Dv BUS_DMA_BUS[1-4]
-These flags are placeholders, and may be used by busses to provide
-bus-dependent functionality.
-.It Dv BUS_DMA_COHERENT
-See
-.Fn bus_dmamem_map
-above for a description of this flag.
-.El
-.El
-.Pp
-Behavior is undefined if invalid arguments are passed
-to
-.Fn bus_dmamem_mmap .
-.Pp
-Returns -1 to indicate failure.  Otherwise, returns an opaque
-value to be interpreted by the device pager.
-.El
-.Sh SEE ALSO
-.Xr bus_space 9
-.Sh AUTHOR
-The
-.Nm
-interface was designed and implemented by Jason R. Thorpe of the
-Numerical Aerospace Simulation Facility, NASA Ames Research Center.
-Additional input on the
-.Nm
-design was provided by Chris Demetriou, Charles Hannum, Ross Harvey,
-Matthew Jacob, Jonathan Stone, and Matt Thomas.
-.Sh HISTORY
-The
-.Nm
-interface appeared in
-.Nx 1.3 .