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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, u_int prot, u_int maxprot, u_int flags, cred_t *credp);

int ddi_segmap_setup(dev_t dev, off_t offset, struct as *asp, caddr_t *addrp, off_t len, u_int prot, u_int maxprot, u_int flags, cred_t *credp, ddi_device_acc_attr_t dev_acc_attr);

Interface Level

Solaris DDI specific (Solaris DDI).

Arguments

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
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.

Description

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() 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() entry point to set up the mapping and assign device access attributes to that mapping. See ddi_device_acc_attr(9S) for details 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() entry point.

Return Values

ddi_segmap() and ddi_segmap_setup() return:
  1. on success.
    non-zero
    on failure. 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.

    See Also

    mmap(2) , mmap(9E) , segmap(9E) , ddi_mapdev(9F) , cb_ops(9S) , ddi_device_acc_attr(9S)

    Notes

    If driver notification of user accesses to the mappings is required, the driver should use ddi_mapdev(9F) instead.

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