118 lines
4.5 KiB
C
118 lines
4.5 KiB
C
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/****************************************************************************
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* drivers/pipe-common.h
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*
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* Copyright (C) 2008 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#ifndef __DRIVERS_PIPE_COMMON_H
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#define __DRIVERS_PIPE_COMMON_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#ifndef CONFIG_DEV_FIFO_SIZE
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# define CONFIG_DEV_FIFO_SIZE 1024
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#endif
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#if CONFIG_DEV_FIFO_SIZE > 0
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/* Maximum number of open's supported on FIFO */
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#define CONFIG_DEV_FIFO_MAXUSER 255
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* Make the FIFO index as small as possible for the configured FIFO size */
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#if CONFIG_DEV_FIFO_SIZE > 65535
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typedef uint32 pipe_ndx_t; /* 32-bit index */
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#elif CONFIG_DEV_FIFO_SIZE > 255
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typedef uint16 pipe_ndx_t; /* 16-bit index */
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#else
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typedef ubyte pipe_ndx_t; /* 8-bit index */
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#endif
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struct pipe_state_s
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{
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sem_t d_bfsem; /* Used to serialize access to d_buffer and indices */
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sem_t d_rdsem; /* Empty buffer - Reader waits for data write */
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sem_t d_wrsem; /* Full buffer - Writer waits for data read */
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pipe_ndx_t d_wrndx; /* Index in d_buffer to save next byte written */
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pipe_ndx_t d_rdndx; /* Index in d_buffer to return the next byte read */
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ubyte d_refs; /* References counts on FIFO (limited to 255) */
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ubyte d_nwriters; /* Number of open counts for write access */
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ubyte d_rdwaiters; /* Number of readers waiting for write data to empty buffer */
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ubyte d_nwrwaiters; /* Number of writers wiating for data read out of full buffer */
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ubyte d_pipeno; /* Pipe minor number */
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};
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struct pipe_dev_s
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{
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struct pipe_state_s s;
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ubyte d_buffer[CONFIG_DEV_FIFO_SIZE];
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};
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#ifdef __cplusplus
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# define EXTERN extern "C"
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extern "C" {
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#else
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# define EXTERN extern
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#endif
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EXTERN FAR struct pipe_dev_s *pipecommon_allocdev(void);
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EXTERN void pipecommon_freedev(FAR struct pipe_dev_s *dev);
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EXTERN int pipecommon_open(FAR struct file *filep);
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EXTERN int pipecommon_close(FAR struct file *filep);
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EXTERN ssize_t pipecommon_read(FAR struct file *, FAR char *, size_t);
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EXTERN ssize_t pipecommon_write(FAR struct file *, FAR const char *, size_t);
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#undef EXTERN
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#ifdef __cplusplus
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}
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#endif
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#endif /* CONFIG_DEV_FIFO_SIZE > 0 */
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#endif /* __DRIVERS_PIPE_COMMON_H */
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