/**************************************************************************** * drivers/pipe/pipe_common.h * * Copyright (C) 2008-2009, 2015 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #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_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'. */ #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; /* Forward 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 #ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS int pipecommon_unlink(FAR struct inode *priv); #endif #undef EXTERN #ifdef __cplusplus } #endif #endif /* CONFIG_DEV_PIPE_SIZE > 0 */ #endif /* __DRIVERS_PIPES_PIPE_COMMON_H */