FreeBSD/Linux Kernel Cross Reference
sys/kern/device_if.m

     #
     # 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.
    #
    # $FreeBSD: releng/5.1/sys/kern/device_if.m 59093 2000-04-08 14:17:18Z dfr $
    #
    
    #include <sys/bus.h>
    
    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. If some other error happens during the
    # probe (such as a memory allocation failure), an appropriate error code
    # should be returned. 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;
    };
    
    #
    # Called by a parent bus to add new devices to the bus.
    #
    STATICMETHOD void identify {
            driver_t *driver;
            device_t parent;
    };
    
    #
    # 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;

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