/**************************************************************************** * inlcude/nuttx/rwbuffer.h * * Copyright (C) 2009 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. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #ifndef __INCLUDE_NUTTX_RWBUFFER_H #define __INCLUDE_NUTTX_RWBUFFER_H /********************************************************************** * Included Files **********************************************************************/ #include #include #include #include #include #if defined(CONFIG_FS_WRITEBUFFER) || defined(CONFIG_FS_READAHEAD) /********************************************************************** * Pre-processor Definitions **********************************************************************/ /********************************************************************** * Public Types **********************************************************************/ /* Data transfer callouts. These must be provided by the block driver * logic in order to flush the write buffer when appropriate or to * reload the read-ahead buffer, when appropriate. */ typedef ssize_t (*rwbreload_t)(FAR void *dev, FAR uint8_t *buffer, off_t startblock, size_t nblocks); typedef ssize_t (*rwbflush_t)(FAR void *dev, FAR const uint8_t *buffer, off_t startblock, size_t nblocks); /* This structure holds the state of the buffers. In typical usage, * an instance of this structure is declared within each block driver * status structure like: * * struct foo_dev_s * { * ... * struct rwbuffer_s rwbuffer; * ... * }; * * Note that this supports buffering for multiple block devices or for * multiple instances of same block device, because each rwbuffer instance * supports independent buffering. * * A reference to the struct rwbuffer_s instance is then passed to each * interface like: * * struct foo_dev_s *priv; * ... * ... [Setup blocksize, nblocks, dev, wrmaxblocks, wrflush, * rhmaxblocks, rhreload] ... * ret = rwb_initialize(&priv->rwbuffer); */ struct rwbuffer_s { /********************************************************************/ /* These values must be provided by the user prior to calling * rwb_initialize() */ /* Supported geometry */ uint16_t blocksize; /* The size of one block */ size_t nblocks; /* The total number blocks supported */ FAR void *dev; /* Device state passed to callout functions */ /* Write buffer setup. If CONFIG_FS_WRITEBUFFER is defined, but you * want read-ahead-only operation, (1) set wrmaxblocks to zero and do * not use rwb_write(). */ #ifdef CONFIG_FS_WRITEBUFFER uint16_t wrmaxblocks; /* The number of blocks to buffer in memory */ rwbflush_t wrflush; /* Callout to flush the write buffer */ #endif /* Read-ahead buffer setup. If CONFIG_FS_READAHEAD is defined but you * want write-buffer-only operation, then (1) set rhmaxblocks to zero and * do not use rwb_read(). */ #ifdef CONFIG_FS_READAHEAD uint16_t rhmaxblocks; /* The number of blocks to buffer in memory */ rwbreload_t rhreload; /* Callout to reload the read-ahead buffer */ #endif /********************************************************************/ /* The user should never modify any of the remaing fields */ /* This is the state of the write buffer */ #ifdef CONFIG_FS_WRITEBUFFER sem_t wrsem; /* Enforces exclusive access to the write buffer */ struct work_s work; /* Delayed work to flush buffer after adelay with no activity */ uint8_t *wrbuffer; /* Allocated write buffer */ uint16_t wrnblocks; /* Number of blocks in write buffer */ off_t wrblockstart; /* First block in write buffer */ off_t wrexpectedblock; /* Next block expected */ #endif /* This is the state of the read-ahead buffer */ #ifdef CONFIG_FS_READAHEAD sem_t rhsem; /* Enforces exclusive access to the write buffer */ uint8_t *rhbuffer; /* Allocated read-ahead buffer */ uint16_t rhnblocks; /* Number of blocks in read-ahead buffer */ off_t rhblockstart; /* First block in read-ahead buffer */ #endif }; /********************************************************************** * Global Variables **********************************************************************/ #undef EXTERN #if defined(__cplusplus) #define EXTERN EXTERN "C" EXTERN "C" { #else #define EXTERN extern #endif /********************************************************************** * Global Function Prototypes **********************************************************************/ /* Buffer initialization */ EXTERN int rwb_initialize(FAR struct rwbuffer_s *rwb); EXTERN void rwb_uninitialize(FAR struct rwbuffer_s *rwb); /* Buffer transfers */ EXTERN ssize_t rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, size_t blockcount, FAR uint8_t *rdbuffer); EXTERN ssize_t rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock, size_t blockcount, FAR const uint8_t *wrbuffer); EXTERN int rwb_mediaremoved(FAR struct rwbuffer_s *rwb); #undef EXTERN #if defined(__cplusplus) } #endif #endif /* CONFIG_FS_WRITEBUFFER || CONFIG_READAHEAD_BUFFER */ #endif /* __INCLUDE_NUTTX_RWBUFFER_H */