scoutos / prex-0.9.0 / bsp / drv / dev / misc / null.c @ 03e9c04a
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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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} |