NAME    [Toc]    [Back]

     BUS_READ_IVAR, BUS_WRITE_IVAR -- manipulate bus-specific device instance
     variables

SYNOPSIS    [Toc]    [Back]

     #include <sys/param.h>
     #include <sys/bus.h>

     int
     BUS_READ_IVAR(device_t dev, device_t child, int index,
	 uintptr_t *result);

     int
     BUS_WRITE_IVAR(device_t dev, device_t child, int index, uintptr_t value);

DESCRIPTION    [Toc]    [Back]

     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.

RETURN VALUES    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

     device(9), driver(9)

AUTHORS    [Toc]    [Back]

     This manual page was written by Doug Rabson.


FreeBSD 5.2.1			 June 16, 1998			 FreeBSD 5.2.1