illumos: manual page: ddi_segmap

DDI_SEGMAP(9F) Kernel Functions for Drivers DDI_SEGMAP(9F)

NAME

ddi_segmap, ddi_segmap_setup - set up a user mapping using seg_dev

SYNOPSIS

#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>

int ddi_segmap(dev_t dev, off_t offset, struct as *asp,
caddr_t *addrp, off_t len, uint_t prot,
uint_t maxprot, uint_t flags, cred_t *credp);

int ddi_segmap_setup(dev_t dev, off_t offset, struct as *asp,
caddr_t *addrp, off_t len, uint_t prot,
uint_t maxprot, uint_t flags, cred_t *credp,
const ddi_device_acc_attr_t *accattrp, uint_t rnumber);

INTERFACE LEVEL

These interfaces are obsolete. See devmap(9E) for an alternative to
ddi_segmap(). Use devmap_setup(9F) instead of ddi_segmap_setup().

PARAMETERS

dev
The device whose memory is to be mapped.

offset
The offset within device memory at which the mapping begins.

asp
An opaque pointer to the user address space into which the
device memory should be mapped.

addrp
Pointer to the starting address within the user address space
to 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 combinations
of possible settings are:

PROT_READ
Read access is desired.

PROT_WRITE
Write access is desired.

PROT_EXEC
Execute access is desired.

PROT_USER
User-level access is desired (the mapping is
being done as a result of a mmap(2) system
call).

PROT_ALL
All access is desired.

maxprot
Maximum protection flag possible for attempted mapping (the
PROT_WRITE bit may be masked out if the user opened the
special file read-only). If (maxprot & prot) != prot then
there is an access violation.

flags
Flags indicating type of mapping. Possible values are (other
bits may be set):

MAP_PRIVATE
Changes are private.

MAP_SHARED
Changes should be shared.

MAP_FIXED
The user specified an address in *addrp
rather than letting the system pick and
address.

credp
Pointer to user credential structure.

ddi_segmap_setup()
dev_acc_attr
Pointer to a ddi_device_acc_attr(9S) structure which
contains the device access attributes to apply to this
mapping.

rnumber
Index number to the register address space set.

DESCRIPTION

Future releases of Solaris will provide this function for binary and
source compatibility. However, for increased functionality, use
ddi_devmap_segmap(9F) instead. See ddi_devmap_segmap(9F) for details.

ddi_segmap() and ddi_segmap_setup() set up user mappings to device space.
When setting up the mapping, the ddi_segmap() and ddi_segmap_setup()
routines call the mmap(9E) entry point to validate the range to be
mapped. When a user process accesses the mapping, the drivers mmap(9E)
entry point is again called to retrieve the page frame number that needs
to be loaded. The mapping translations for that page are then loaded on
behalf of the driver by the DDI framework.

ddi_segmap() is typically used as the segmap(9E) entry in the cb_ops(9S)
structure for those devices that do not choose to provide their own
segmap(9E) entry point. However, some drivers may have their own
segmap(9E) entry point to do some initial processing on the parameters
and then call ddi_segmap() to establish the default memory mapping.

ddi_segmap_setup() is used in the drivers segmap(9E) entry point to set
up the mapping and assign device access attributes to that mapping.
rnumber specifies the register set representing the range of device
memory being mapped. See ddi_device_acc_attr(9S) for details regarding
what device access attributes are available.

ddi_segmap_setup() cannot be used directly in the cb_ops(9S) structure
and requires a driver to have a segmap(9E) entry point.

RETURN VALUES

ddi_segmap() and ddi_segmap_setup() return the following values:

0
Successful completion.

Non-zero
An error occurred. In particular, they return ENXIO if the
range to be mapped is invalid.

CONTEXT

ddi_segmap() and ddi_segmap_setup() can be called from user or kernel
context only.

ATTRIBUTES