Kernel Functions for Drivers devmapsetup(9F)
NAME
devmapsetup, ddidevmapsegmap - set up a user mapping to
device memory using the devmap framework
SYNOPSIS
#include
#include
int devmapsetup(devt dev, offsett off, ddiashandlet as,
caddrt *addrp, sizetlen, uintt prot, uintt maxprot,
uintt flags, credt *cred);
int ddidevmapsegmap(devt dev, offt off, ddiashandlet as,
caddrt *addrp, offtlen, uintt prot, uintt maxprot,
uintt flags, credt *cred);
INTERFACE LEVEL
Solaris DI specific (Solaris DI).
PARAMETERS
dev Device whose memory is to be mapped.
off User offset within the logical device memory at
which the mapping begins.
as An opaque data structure that describes the
address space into which the device memory
should be mapped.
addrp Pointer to the starting address in the address
space into which the device memory should be
mapped.
len Length (in bytes) of the memory to be mapped.
prot A bit field that specifies the protections. Some
possible settings combinations are:
PROTREAD Read access is desired.
PROTWRITE Write access is desired.
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Kernel Functions for Drivers devmapsetup(9F)
PROTEXEC Execute access is desired.
PROTUSER User-level access is desired (the
mapping is being done as a result
of a mmap(2) system call).
PROTAL All access is desired.
maxprot Maximum protection flag possible for attempted
mapping; the PROTWRITE bit may be masked out if
the user opened the special file read-only.
flags Flags indicating type of mapping. The following
flags can be specified:
MAPRIVATE Changes are private.
MAPSHARED Changes should be shared.
MAPFIXED The user specified an address in
*addrp rather than letting the
system choose an address.
cred Pointer to the user credential structure.
DESCRIPTION
devmapsetup() and ddidevmapsegmap() allow device drivers
to use the devmap framework to set up user mappings to dev-
ice memory. The devmap framework provides several advan-
tages over the default device mapping framework that is used
by ddisegmap(9F) or ddisegmapsetup(9F). Device drivers
should use the devmap framework, if the driver wants to:
o use an optimal MU pagesize to minimize address
translations,
o conserve kernel resources,
o receive callbacks to manage events on the mapping,
o export kernel memory to applications,
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Kernel Functions for Drivers devmapsetup(9F)
o set up device contexts for the user mapping if the
device requires context switching,
o assign device access attributes to the user map-
ping, or
o change the maximum protection for the mapping.
devmapsetup() must be called in the segmap(9E) entry point
to establish the mapping for the application.
ddidevmapsegmap() can be called in, or be used as, the
segmap(9E) entry point. The differences between
devmapsetup() and ddidevmapsegmap() are in the data type
used for off and len.
When setting up the mapping, devmapsetup() and
ddidevmapsegmap() call the devmap(9E) entry point to vali-
date the range to be mapped. The devmap(9E) entry point also
translates the logical offset (as seen by the application)
to the corresponding physical offset within the device
address space. If the driver does not provide its own
devmap(9E) entry point, EINVAL will be returned to the
mmap(2) system call.
RETURN VALUES
0 Successful completion.
Non-zero An error occurred. The return value of
devmapsetup() and ddidevmapsegmap() should be
used directly in the segmap(9E) entry point.
CONTEXT
devmapsetup() and ddidevmapsegmap() can be called from
user or kernel context only.
SEE ALSO
mmap(2), devmap(9E), segmap(9E), ddisegmap(9F),
ddisegmapsetup(9F), cbops(9S)
Writing Device Drivers
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