Copyright (c) 1998 Doug Rabson All rights reserved. This program is free software. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in...
NAMEBUS_READ_IVAR BUS_WRITE_IVAR - manipulate bus-specific device instance variables
SYNOPSISIn sys/param.h In sys/bus.h Ft int Fn BUS_READ_IVAR device_t dev device_t child int index uintptr_t *result Ft int Fn BUS_WRITE_IVAR device_t dev device_t child int index uintptr_t value
DESCRIPTIONThese 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.