BUS_READ_IVAR, BUS_WRITE_IVAR — manipulate bus-specific device instance variables

       This manual page was written by Doug Rabson.

Debian                                            June 16, 1998                                 BUS_READ_IVAR(9)

       These  two  methods  manage a bus specific set of instance variables of a child device.  The intention is
       that each different type of bus defines a set of appropriate instance variables (such as ports  and  irqs
       for ISA bus etc.)

       This  information  could be given to the child device as a struct but that makes it hard for a bus to add
       or remove variables without forcing an edit and recompile for all drivers which may not be  possible  for
       vendor supplied binary drivers.

       BUS_READ_IVAR, BUS_WRITE_IVAR — manipulate bus-specific device instance variables

       Zero is returned on success, otherwise an appropriate error is returned.

device(9), driver(9)

#include<sys/param.h>#include<sys/bus.h>intBUS_READ_IVAR(device_tdev, device_tchild, intindex, uintptr_t*result);

       intBUS_WRITE_IVAR(device_tdev, device_tchild, intindex, uintptr_tvalue);