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/*-
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 * Copyright (c) 2005-2006, Kohsuke Ohtani
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the author nor the names of any co-contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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/*
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 * null.c - null device
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 */
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#include <driver.h>
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static int null_read(device_t, char *, size_t *, int);
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static int null_write(device_t, char *, size_t *, int);
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static int null_init(struct driver *);
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static struct devops null_devops = {
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        /* open */        no_open,
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        /* close */        no_close,
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        /* read */        null_read,
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        /* write */        null_write,
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        /* ioctl */        no_ioctl,
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        /* devctl */        no_devctl,
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};
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struct driver null_driver = {
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        /* name */        "null",
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        /* devops */        &null_devops,
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        /* devsz */        0,
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        /* flags */        0,
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        /* probe */        NULL,
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        /* init */        null_init,
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        /* shutdown */        NULL,
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};
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/*
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 * Always returns 0 bytes as the read size.
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 */
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static int
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null_read(device_t dev, char *buf, size_t *nbyte, int blkno)
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{
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        *nbyte = 0;
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        return 0;
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}
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/*
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 * Data written to this device is discarded.
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 */
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static int
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null_write(device_t dev, char *buf, size_t *nbyte, int blkno)
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{
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        return 0;
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}
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static int
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null_init(struct driver *self)
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{
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        device_create(self, "null", D_CHR);
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        return 0;
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}