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- /****************************************************************************
- * include/nuttx/drivers/rwbuffer.h
- *
- * Copyright (C) 2009, 2014, 2020 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <gnutt@nuttx.org>
- *
- * 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 __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H
- #define __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H
- /****************************************************************************
- * Included Files
- ****************************************************************************/
- #include <nuttx/config.h>
- #include <sys/types.h>
- #include <stdint.h>
- #include <nuttx/semaphore.h>
- #include <nuttx/wqueue.h>
- #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
- sem_t wrsem; /* Enforces exclusive access to the write buffer */
- struct work_s work; /* Delayed work to flush buffer after a delay 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 */
- #endif
- /* This is the state of the read-ahead buffering */
- #ifdef CONFIG_DRVR_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
- };
- /****************************************************************************
- * 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 */
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