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/****************************************************************************
* drivers/pipe/pipe_common.h
*
* Copyright (C) 2008-2009, 2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#ifndef __DRIVERS_PIPES_PIPE_COMMON_H
#define __DRIVERS_PIPES_PIPE_COMMON_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <poll.h>
#ifndef CONFIG_DEV_PIPE_SIZE
# define CONFIG_DEV_PIPE_SIZE 1024
#endif
#if CONFIG_DEV_PIPE_SIZE > 0
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Maximum number of threads than can be waiting for POLL events */
#ifndef CONFIG_DEV_PIPE_NPOLLWAITERS
# define CONFIG_DEV_PIPE_NPOLLWAITERS 2
#endif
/* Maximum number of open's supported on pipe */
#define CONFIG_DEV_PIPE_MAXUSER 255
/* d_flags values */
#define PIPE_FLAG_POLICY (1 << 0) /* Bit 0: Policy=Free buffer when empty */
#define PIPE_FLAG_UNLINKED (1 << 1) /* Bit 1: The driver has been unlinked */
#define PIPE_POLICY_0(f) do { (f) &= ~PIPE_FLAG_POLICY; } while (0)
#define PIPE_POLICY_1(f) do { (f) |= PIPE_FLAG_POLICY; } while (0)
#define PIPE_IS_POLICY_0(f) (((f) & PIPE_FLAG_POLICY) == 0)
#define PIPE_IS_POLICY_1(f) (((f) & PIPE_FLAG_POLICY) != 0)
#define PIPE_UNLINK(f) do { (f) |= PIPE_FLAG_UNLINKED; } while (0)
#define PIPE_IS_UNLINKED(f) (((f) & PIPE_FLAG_UNLINKED) != 0)
/****************************************************************************
* Public Types
****************************************************************************/
/* Make the buffer index as small as possible for the configured pipe size */
#if CONFIG_DEV_PIPE_SIZE > 65535
typedef uint32_t pipe_ndx_t; /* 32-bit index */
#elif CONFIG_DEV_PIPE_SIZE > 255
typedef uint16_t pipe_ndx_t; /* 16-bit index */
#else
typedef uint8_t pipe_ndx_t; /* 8-bit index */
#endif
/* This structure represents the state of one pipe. A reference to this
* structure is retained in the i_private field of the inode whenthe pipe/fifo
* device is registered.
*/
struct pipe_dev_s
{
sem_t d_bfsem; /* Used to serialize access to d_buffer and indices */
sem_t d_rdsem; /* Empty buffer - Reader waits for data write */
sem_t d_wrsem; /* Full buffer - Writer waits for data read */
pipe_ndx_t d_wrndx; /* Index in d_buffer to save next byte written */
pipe_ndx_t d_rdndx; /* Index in d_buffer to return the next byte read */
uint8_t d_refs; /* References counts on pipe (limited to 255) */
uint8_t d_nwriters; /* Number of reference counts for write access */
uint8_t d_pipeno; /* Pipe minor number */
uint8_t d_flags; /* See PIPE_FLAG_* definitions */
uint8_t *d_buffer; /* Buffer allocated when device opened */
/* The following is a list if poll structures of threads waiting for
* driver events. The 'struct pollfd' reference for each open is also
* retained in the f_priv field of the 'struct file'.
*/
#ifndef CONFIG_DISABLE_POLL
struct pollfd *d_fds[CONFIG_DEV_PIPE_NPOLLWAITERS];
#endif
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
# define EXTERN extern "C"
extern "C" {
#else
# define EXTERN extern
#endif
struct file; /* Forward reference */
struct inode; /* Forware reference */
FAR struct pipe_dev_s *pipecommon_allocdev(void);
void pipecommon_freedev(FAR struct pipe_dev_s *dev);
int pipecommon_open(FAR struct file *filep);
int pipecommon_close(FAR struct file *filep);
ssize_t pipecommon_read(FAR struct file *, FAR char *, size_t);
ssize_t pipecommon_write(FAR struct file *, FAR const char *, size_t);
int pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
#ifndef CONFIG_DISABLE_POLL
int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
#endif
int pipecommon_unlink(FAR struct inode *priv);
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* CONFIG_DEV_PIPE_SIZE > 0 */
#endif /* __DRIVERS_PIPES_PIPE_COMMON_H */
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