137 lines
5.1 KiB
C
137 lines
5.1 KiB
C
/****************************************************************************
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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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#include <poll.h>
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#ifndef CONFIG_DEV_PIPE_SIZE
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# define CONFIG_DEV_PIPE_SIZE 1024
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#endif
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#if CONFIG_DEV_PIPE_SIZE > 0
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/* Maximum number of threads than can be waiting for POLL events */
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#ifndef CONFIG_DEV_PIPE_NPOLLWAITERS
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# define CONFIG_DEV_PIPE_NPOLLWAITERS 2
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#endif
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/* Maximum number of open's supported on pipe */
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#define CONFIG_DEV_PIPE_MAXUSER 255
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* Make the buffer index as small as possible for the configured pipe size */
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#if CONFIG_DEV_PIPE_SIZE > 65535
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typedef uint32 pipe_ndx_t; /* 32-bit index */
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#elif CONFIG_DEV_PIPE_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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/* This structure represents the state of one pipe. A reference to this
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* structure is retained in the i_private field of the inode whenthe pipe/fifo
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* device is registered.
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*/
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struct pipe_dev_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 pipe (limited to 255) */
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ubyte d_nwriters; /* Number of reference counts for write access */
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ubyte d_pipeno; /* Pipe minor number */
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ubyte *d_buffer; /* Buffer allocated when device opened */
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/* The following is a list if poll structures of threads waiting for
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* driver events. The 'struct pollfd' reference for each open is also
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* retained in the f_priv field of the 'struct file'.
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*/
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#ifndef CONFIG_DISABLE_POLL
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struct pollfd *d_fds[CONFIG_DEV_PIPE_NPOLLWAITERS];
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#endif
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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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#ifndef CONFIG_DISABLE_POLL
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EXTERN int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
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boolean setup);
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#endif
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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_PIPE_SIZE > 0 */
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#endif /* __DRIVERS_PIPE_COMMON_H */
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