208 lines
7.2 KiB
C
208 lines
7.2 KiB
C
/****************************************************************************
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* include/nuttx/drivers/rwbuffer.h
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*
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* SPDX-License-Identifier: Apache-2.0
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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 __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H
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#define __INCLUDE_NUTTX_DRIVERS_RWBUFFER_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 <sys/types.h>
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#include <stdint.h>
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#include <nuttx/mutex.h>
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#include <nuttx/wqueue.h>
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#if defined(CONFIG_DRVR_WRITEBUFFER) || defined(CONFIG_DRVR_READAHEAD)
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Types
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****************************************************************************/
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/* Data transfer callouts. These must be provided by the block driver
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* logic in order to flush the write buffer when appropriate or to
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* reload the read-ahead buffer, when appropriate.
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*/
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typedef CODE ssize_t (*rwbreload_t)(FAR void *dev, FAR uint8_t *buffer,
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off_t startblock, size_t nblocks);
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typedef CODE ssize_t (*rwbflush_t)(FAR void *dev, FAR const uint8_t *buffer,
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off_t startblock, size_t nblocks);
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/* This structure holds the state of the buffers. In typical usage,
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* an instance of this structure is declared within each block driver
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* status structure like:
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*
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* struct foo_dev_s
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* {
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* ...
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* struct rwbuffer_s rwbuffer;
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* ...
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* };
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*
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* Note that this supports buffering for multiple block devices or for
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* multiple instances of same block device, because each rwbuffer instance
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* supports independent buffering.
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*
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* A reference to the struct rwbuffer_s instance is then passed to each
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* interface like:
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*
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* FAR struct foo_dev_s *priv;
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* ...
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* ... [Setup blocksize, nblocks, dev, wrmaxblocks, wrflush,
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* rhmaxblocks, rhreload] ...
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* ret = rwb_initialize(&priv->rwbuffer);
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*/
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struct rwbuffer_s
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{
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/**************************************************************************/
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/* These values must be provided by the user prior to calling
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* rwb_initialize()
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*/
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/* Supported geometry */
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uint16_t blocksize; /* The size of one block */
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size_t nblocks; /* The total number blocks supported */
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/* Read-ahead/Write buffer sizes. Buffering can be disabled (even if it
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* is enabled in the configuration) by setting the buffer size to zero
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* blocks.
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*/
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#ifdef CONFIG_DRVR_WRITEBUFFER
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uint16_t wrmaxblocks; /* The number of blocks to buffer in memory */
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uint16_t wralignblocks; /* The buffer to be flash is always multiplied by this
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* number. It must be 0 or divisible by wrmaxblocks.
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*/
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#endif
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#ifdef CONFIG_DRVR_READAHEAD
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uint16_t rhmaxblocks; /* The number of blocks to buffer in memory */
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#endif
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/* Callback functions.
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*
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* wrflush. This callback is normally used to flush the contents of
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* the write buffer. If write buffering is disabled, then this
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* function will instead be used to perform unbuffered writes.
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* rhrelad. This callback is normally used to read new data into the
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* read-ahead buffer. If read-ahead buffering is disabled, then this
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* function will instead be used to perform unbuffered reads.
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*/
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FAR void *dev; /* Device state passed to callout functions */
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rwbflush_t wrflush; /* Callout to flush the write buffer */
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rwbreload_t rhreload; /* Callout to reload the read-ahead buffer */
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/**************************************************************************/
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/* The user should never modify any of the remaining fields */
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/* This is the state of the write buffering */
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#ifdef CONFIG_DRVR_WRITEBUFFER
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mutex_t wrlock; /* Enforces exclusive access to the write buffer */
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struct work_s work; /* Delayed work to flush buffer after a delay with no activity */
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FAR uint8_t *wrbuffer; /* Allocated write buffer */
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uint16_t wrnblocks; /* Number of blocks in write buffer */
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off_t wrblockstart; /* First block in write buffer */
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#endif
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/* This is the state of the read-ahead buffering */
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#ifdef CONFIG_DRVR_READAHEAD
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mutex_t rhlock; /* Enforces exclusive access to the read-ahead buffer */
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FAR uint8_t *rhbuffer; /* Allocated read-ahead buffer */
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uint16_t rhnblocks; /* Number of blocks in read-ahead buffer */
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off_t rhblockstart; /* First block in read-ahead buffer */
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#endif
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};
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/****************************************************************************
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* Public Data
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****************************************************************************/
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#undef EXTERN
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#if defined(__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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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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/* Buffer initialization */
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int rwb_initialize(FAR struct rwbuffer_s *rwb);
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void rwb_uninitialize(FAR struct rwbuffer_s *rwb);
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/* Block oriented transfers */
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ssize_t rwb_read(FAR struct rwbuffer_s *rwb, off_t startblock,
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size_t blockcount, FAR uint8_t *rdbuffer);
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ssize_t rwb_write(FAR struct rwbuffer_s *rwb,
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off_t startblock, size_t blockcount,
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FAR const uint8_t *wrbuffer);
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/* Character oriented transfers */
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#ifdef CONFIG_DRVR_READBYTES
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ssize_t rwb_readbytes(FAR struct rwbuffer_s *dev, off_t offset,
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size_t nbytes, FAR uint8_t *buffer);
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#endif
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/* Media events */
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#ifdef CONFIG_DRVR_REMOVABLE
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int rwb_mediaremoved(FAR struct rwbuffer_s *rwb);
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#endif
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#ifdef CONFIG_DRVR_INVALIDATE
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int rwb_invalidate(FAR struct rwbuffer_s *rwb,
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off_t startblock, size_t blockcount);
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#endif
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#ifdef CONFIG_DRVR_WRITEBUFFER
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int rwb_flush(FAR struct rwbuffer_s *rwb);
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#endif
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#undef EXTERN
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#if defined(__cplusplus)
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}
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#endif
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#endif /* CONFIG_DRVR_WRITEBUFFER || CONFIG_DRVR_READAHEAD */
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#endif /* __INCLUDE_NUTTX_DRIVERS_RWBUFFER_H */
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