freebsd-nq/sys/kern/device_if.m
Doug Rabson 8b2970bbe6 * Augment the interface language to allow arbitrary C code to be 'passed
through' to the C compiler.
* Allow the interface to specify a default implementation for methods.
* Allow 'static' methods which are not device specific.
* Add a simple scheme for probe routines to return a priority value. To
  make life simple, priority values are negative numbers (positive numbers
  are standard errno codes) with zero being the highest priority. The
  driver which returns the highest priority will be chosen for the device.
1999-05-10 17:06:14 +00:00

117 lines
3.9 KiB
Objective-C

#
# Copyright (c) 1998 Doug Rabson
# All rights reserved.
#
# 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 the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $Id: device_if.m,v 1.3 1998/11/14 21:58:51 wollman Exp $
#
INTERFACE device;
#
# Default implementations of some methods.
#
CODE {
static int null_shutdown(device_t dev)
{
return 0;
}
static int null_suspend(device_t dev)
{
return 0;
}
static int null_resume(device_t dev)
{
return 0;
}
};
#
# Probe to see if the device is present. Return 0 if the device exists,
# ENXIO if it cannot be found. For cases where more than one driver
# matches a device, a priority value can be returned. In this case,
# success codes are values less than or equal to zero with the highest
# value representing the best match. Failure codes are represented by
# positive values and the regular unix error codes should be used for
# the purpose.
#
# If a driver returns a success code which is less than zero, it must
# not assume that it will be the same driver which is attached to the
# device. In particular, it must not assume that any values stored in
# the softc structure will be available for its attach method and any
# resources allocated during probe must be released and re-allocated
# if the attach method is called. If a success code of zero is
# returned, the driver can assume that it will be the one attached.
#
# Devices which implement busses should use this method to probe for
# the existence of devices attached to the bus and add them as
# children. If this is combined with the use of bus_generic_attach,
# the child devices will be automatically probed and attached.
#
METHOD int probe {
device_t dev;
};
#
# Attach a device to the system. The probe method will have been
# called and will have indicated that the device exists. This routine
# should initialise the hardware and allocate other system resources
# (such as devfs entries). Returns 0 on success.
#
METHOD int attach {
device_t dev;
};
#
# Detach a device. This can be called if the user is replacing the
# driver software or if a device is about to be physically removed
# from the system (e.g. for pccard devices). Returns 0 on success.
#
METHOD int detach {
device_t dev;
};
#
# This is called during system shutdown to allow the driver to put the
# hardware into a consistent state for rebooting the computer.
#
METHOD int shutdown {
device_t dev;
} DEFAULT null_shutdown;
#
# This is called by the power-management subsystem when a suspend has been
# requested by the user or by some automatic mechanism. This gives
# drivers a chance to veto the suspend or save their configuration before
# power is removed.
#
METHOD int suspend {
device_t dev;
} DEFAULT null_suspend;
METHOD int resume {
device_t dev;
} DEFAULT null_resume;