nuttx/drivers/pipes/pipe_common.h
2021-03-09 23:18:28 +08:00

170 lines
5.8 KiB
C

/****************************************************************************
* drivers/pipes/pipe_common.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
#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>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Pipe/FIFO support */
#ifndef CONFIG_PIPES
# undef CONFIG_DEV_PIPE_MAXSIZE
# undef CONFIG_DEV_PIPE_SIZE
# undef CONFIG_DEV_FIFO_SIZE
# define CONFIG_DEV_PIPE_MAXSIZE 0
# define CONFIG_DEV_PIPE_SIZE 0
# define CONFIG_DEV_FIFO_SIZE 0
#endif
/* Pipe/FIFO size */
#ifndef CONFIG_DEV_PIPE_MAXSIZE
# define CONFIG_DEV_PIPE_MAXSIZE 1024
#endif
#if CONFIG_DEV_PIPE_MAXSIZE <= 0
# undef CONFIG_PIPES
# undef CONFIG_DEV_PIPE_SIZE
# undef CONFIG_DEV_FIFO_SIZE
# define CONFIG_DEV_PIPE_SIZE 0
# define CONFIG_DEV_FIFO_SIZE 0
#endif
#ifndef CONFIG_DEV_PIPE_SIZE
# define CONFIG_DEV_PIPE_SIZE 1024
#endif
#ifndef CONFIG_DEV_FIFO_SIZE
# define CONFIG_DEV_FIFO_SIZE 1024
#endif
/* 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_MAXSIZE > 65535
typedef uint32_t pipe_ndx_t; /* 32-bit index */
#elif CONFIG_DEV_PIPE_MAXSIZE > 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 */
pipe_ndx_t d_bufsize; /* allocated size of d_buffer in bytes */
uint8_t d_nwriters; /* Number of reference counts for write access */
uint8_t d_nreaders; /* Number of reference counts for read 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'.
*/
struct pollfd *d_fds[CONFIG_DEV_PIPE_NPOLLWAITERS];
};
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
# define EXTERN extern "C"
extern "C"
{
#else
# define EXTERN extern
#endif
struct file; /* Forward reference */
struct inode; /* Forward reference */
FAR struct pipe_dev_s *pipecommon_allocdev(size_t bufsize);
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);
int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup);
#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
int pipecommon_unlink(FAR struct inode *priv);
#endif
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __DRIVERS_PIPES_PIPE_COMMON_H */