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

NAME

ddi_get_instance - get device instance number

SYNOPSIS

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


int ddi_get_instance(dev_info_t *dip);

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

PARAMETERS

dip
Pointer to dev_info structure.

DESCRIPTION

The ddi_get_instance() function returns the instance number of the device
corresponding to dip.


The system assigns an instance number to every device. Instance numbers
for devices attached to the same driver are unique. This provides a way
for the system and the driver to uniquely identify one or more devices of
the same type. The instance number is derived by the system from
different properties for different device types in an implementation
specific manner.


Once an instance number has been assigned to a device, it will remain the
same even across reconfigurations and reboots. Therefore, instance
numbers seen by a driver may not appear to be in consecutive order. For
example, if device foo0 has been assigned an instance number of 0 and
device foo1 has been assigned an instance number of 1, if foo0 is
removed, foo1 will continue to be associated with instance number 1 (even
though foo1 is now the only device of its type on the system).

RETURN VALUES

The ddi_get_instance() function returns the instance number of the device
corresponding to dip.

CONTEXT

The ddi_get_instance() function can be called from user, interrupt, or
kernel context.

SEE ALSO

path_to_inst(5)


Writing Device Drivers

January 16, 2006 DDI_GET_INSTANCE(9F)