/**************************************************************************** * include/nuttx/drivers/rwbuffer.h * * SPDX-License-Identifier: Apache-2.0 * * 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 __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H #define __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #if defined(CONFIG_DRVR_WRITEBUFFER) || defined(CONFIG_DRVR_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 CODE ssize_t (*rwbreload_t)(FAR void *dev, FAR uint8_t *buffer, off_t startblock, size_t nblocks); typedef CODE 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: * * FAR 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 */ /* Read-ahead/Write buffer sizes. Buffering can be disabled (even if it * is enabled in the configuration) by setting the buffer size to zero * blocks. */ #ifdef CONFIG_DRVR_WRITEBUFFER uint16_t wrmaxblocks; /* The number of blocks to buffer in memory */ uint16_t wralignblocks; /* The buffer to be flash is always multiplied by this * number. It must be 0 or divisible by wrmaxblocks. */ #endif #ifdef CONFIG_DRVR_READAHEAD uint16_t rhmaxblocks; /* The number of blocks to buffer in memory */ #endif /* Callback functions. * * wrflush. This callback is normally used to flush the contents of * the write buffer. If write buffering is disabled, then this * function will instead be used to perform unbuffered writes. * rhrelad. This callback is normally used to read new data into the * read-ahead buffer. If read-ahead buffering is disabled, then this * function will instead be used to perform unbuffered reads. */ FAR void *dev; /* Device state passed to callout functions */ rwbflush_t wrflush; /* Callout to flush the write buffer */ rwbreload_t rhreload; /* Callout to reload the read-ahead buffer */ /**************************************************************************/ /* The user should never modify any of the remaining fields */ /* This is the state of the write buffering */ #ifdef CONFIG_DRVR_WRITEBUFFER mutex_t wrlock; /* Enforces exclusive access to the write buffer */ struct work_s work; /* Delayed work to flush buffer after a delay with no activity */ FAR uint8_t *wrbuffer; /* Allocated write buffer */ uint16_t wrnblocks; /* Number of blocks in write buffer */ off_t wrblockstart; /* First block in write buffer */ #endif /* This is the state of the read-ahead buffering */ #ifdef CONFIG_DRVR_READAHEAD mutex_t rhlock; /* Enforces exclusive access to the read-ahead buffer */ FAR 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 }; /**************************************************************************** * Public Data ****************************************************************************/ #undef EXTERN #if defined(__cplusplus) #define EXTERN extern "C" extern "C" { #else #define EXTERN extern #endif /**************************************************************************** * Public Function Prototypes ****************************************************************************/ /* Buffer initialization */ int rwb_initialize(FAR struct rwbuffer_s *rwb); void rwb_uninitialize(FAR struct rwbuffer_s *rwb); /* Block oriented transfers */ ssize_t rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock, size_t blockcount, FAR uint8_t *rdbuffer); ssize_t rwb_write(FAR struct rwbuffer_s *rwb, off_t startblock, size_t blockcount, FAR const uint8_t *wrbuffer); /* Character oriented transfers */ #ifdef CONFIG_DRVR_READBYTES ssize_t rwb_readbytes(FAR struct rwbuffer_s *dev, off_t offset, size_t nbytes, FAR uint8_t *buffer); #endif /* Media events */ #ifdef CONFIG_DRVR_REMOVABLE int rwb_mediaremoved(FAR struct rwbuffer_s *rwb); #endif #ifdef CONFIG_DRVR_INVALIDATE int rwb_invalidate(FAR struct rwbuffer_s *rwb, off_t startblock, size_t blockcount); #endif #ifdef CONFIG_DRVR_WRITEBUFFER int rwb_flush(FAR struct rwbuffer_s *rwb); #endif #undef EXTERN #if defined(__cplusplus) } #endif #endif /* CONFIG_DRVR_WRITEBUFFER || CONFIG_DRVR_READAHEAD */ #endif /* __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H */