This new ioctl function allows to perform I/O stream specific requests through a generic interface. This provides an easy way to extend the I/O interface with some driver specific features, without having to modify the public api.
74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
/*
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* libdivecomputer
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*
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* Copyright (C) 2019 Jef Driesen
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301 USA
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*/
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#ifndef DC_IOCTL_H
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#define DC_IOCTL_H
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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/*
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* Ioctl direction bits.
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*
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* Note: WRITE means the application is writing and the driver is
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* reading. READ means the application is reading and the driver is
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* writing.
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*/
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#define DC_IOCTL_DIR_NONE 0u
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#define DC_IOCTL_DIR_READ 1u
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#define DC_IOCTL_DIR_WRITE 2u
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/*
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* Ioctl variable size bits.
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*/
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#define DC_IOCTL_SIZE_VARIABLE 0
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/*
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* Helper macro to encode ioctl numbers.
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*/
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#define DC_IOCTL_BASE(dir,type,nr,size) \
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(((dir) << 30) | \
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((size) << 16) | \
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((type) << 8) | \
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((nr) << 0))
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/*
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* Macros to encode ioctl numbers.
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*/
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#define DC_IOCTL_IO(type,nr) DC_IOCTL_BASE(DC_IOCTL_DIR_NONE, (type), (nr), 0)
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#define DC_IOCTL_IOR(type,nr,size) DC_IOCTL_BASE(DC_IOCTL_DIR_READ, (type), (nr), (size))
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#define DC_IOCTL_IOW(type,nr,size) DC_IOCTL_BASE(DC_IOCTL_DIR_WRITE, (type), (nr), (size))
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#define DC_IOCTL_IORW(type,nr,size) DC_IOCTL_BASE(DC_IOCTL_DIR_READ | DC_IOCTL_DIR_WRITE, (type), (nr), (size))
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/*
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* Macros to decode ioctl numbers.
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*/
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#define DC_IOCTL_DIR(request) (((request) >> 30) & 0x0003)
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#define DC_IOCTL_SIZE(request) (((request) >> 16) & 0x3FFF)
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#define DC_IOCTL_TYPE(request) (((request) >> 8) & 0x00FF)
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#define DC_IOCTL_NR(request) (((request) >> 0) & 0x00FF)
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* DC_IOCTL_H */
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