170 lines
5.7 KiB
C
170 lines
5.7 KiB
C
/****************************************************************************
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* drivers/pipes/pipe_common.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __DRIVERS_PIPES_PIPE_COMMON_H
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#define __DRIVERS_PIPES_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 <nuttx/mutex.h>
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#include <sys/types.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include <poll.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* Pipe/FIFO support */
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#ifndef CONFIG_PIPES
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# undef CONFIG_DEV_PIPE_MAXSIZE
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# undef CONFIG_DEV_PIPE_SIZE
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# undef CONFIG_DEV_FIFO_SIZE
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# define CONFIG_DEV_PIPE_MAXSIZE 0
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# define CONFIG_DEV_PIPE_SIZE 0
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# define CONFIG_DEV_FIFO_SIZE 0
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#endif
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/* Pipe/FIFO size */
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#ifndef CONFIG_DEV_PIPE_MAXSIZE
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# define CONFIG_DEV_PIPE_MAXSIZE 1024
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#endif
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#if CONFIG_DEV_PIPE_MAXSIZE <= 0
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# undef CONFIG_PIPES
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# undef CONFIG_DEV_PIPE_SIZE
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# undef CONFIG_DEV_FIFO_SIZE
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# define CONFIG_DEV_PIPE_SIZE 0
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# define CONFIG_DEV_FIFO_SIZE 0
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#endif
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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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#ifndef CONFIG_DEV_FIFO_SIZE
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# define CONFIG_DEV_FIFO_SIZE 1024
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#endif
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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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/* d_flags values */
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#define PIPE_FLAG_POLICY (1 << 0) /* Bit 0: Policy=Free buffer when empty */
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#define PIPE_FLAG_UNLINKED (1 << 1) /* Bit 1: The driver has been unlinked */
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#define PIPE_POLICY_0(f) do { (f) &= ~PIPE_FLAG_POLICY; } while (0)
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#define PIPE_POLICY_1(f) do { (f) |= PIPE_FLAG_POLICY; } while (0)
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#define PIPE_IS_POLICY_0(f) (((f) & PIPE_FLAG_POLICY) == 0)
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#define PIPE_IS_POLICY_1(f) (((f) & PIPE_FLAG_POLICY) != 0)
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#define PIPE_UNLINK(f) do { (f) |= PIPE_FLAG_UNLINKED; } while (0)
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#define PIPE_IS_UNLINKED(f) (((f) & PIPE_FLAG_UNLINKED) != 0)
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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_MAXSIZE > 65535
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typedef uint32_t pipe_ndx_t; /* 32-bit index */
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#elif CONFIG_DEV_PIPE_MAXSIZE > 255
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typedef uint16_t pipe_ndx_t; /* 16-bit index */
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#else
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typedef uint8_t 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
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* pipe/fifo device is registered.
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*/
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struct pipe_dev_s
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{
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mutex_t d_bflock; /* 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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pipe_ndx_t d_bufsize; /* allocated size of d_buffer in bytes */
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uint8_t d_nwriters; /* Number of reference counts for write access */
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uint8_t d_nreaders; /* Number of reference counts for read access */
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uint8_t d_flags; /* See PIPE_FLAG_* definitions */
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uint8_t *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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struct pollfd *d_fds[CONFIG_DEV_PIPE_NPOLLWAITERS];
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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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{
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#else
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# define EXTERN extern
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#endif
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struct file; /* Forward reference */
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struct inode; /* Forward reference */
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FAR struct pipe_dev_s *pipecommon_allocdev(size_t bufsize);
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void pipecommon_freedev(FAR struct pipe_dev_s *dev);
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int pipecommon_open(FAR struct file *filep);
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int pipecommon_close(FAR struct file *filep);
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ssize_t pipecommon_read(FAR struct file *, FAR char *, size_t);
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ssize_t pipecommon_write(FAR struct file *, FAR const char *, size_t);
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int pipecommon_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
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int pipecommon_poll(FAR struct file *filep, FAR struct pollfd *fds,
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bool setup);
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#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
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int pipecommon_unlink(FAR struct inode *priv);
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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 /* __DRIVERS_PIPES_PIPE_COMMON_H */
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