275 lines
8.8 KiB
C
275 lines
8.8 KiB
C
/****************************************************************************
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* fs/nxffs/nxffs_cache.c
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*
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* Copyright (C) 2011, 2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* References: Linux/Documentation/filesystems/romfs.txt
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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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 <assert.h>
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#include <errno.h>
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#include <debug.h>
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#include <nuttx/mtd/mtd.h>
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#include "nxffs.h"
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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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/****************************************************************************
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* Public Variables
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxffs_rdcache
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*
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* Description:
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* Read one I/O block into the volume block cache memory.
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*
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* Input Parameters:
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* volume - Describes the current volume
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* block - The first logical block to read
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*
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* Returned Value:
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* Negated errnos are returned only in the case of MTD reported failures.
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* Nothing in the volume data itself will generate errors.
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*
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****************************************************************************/
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int nxffs_rdcache(FAR struct nxffs_volume_s *volume, off_t block)
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{
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size_t nxfrd;
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/* Check if the requested data is already in the cache */
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if (block != volume->cblock)
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{
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/* Read the specified blocks into cache */
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nxfrd = MTD_BREAD(volume->mtd, block, 1, volume->cache);
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if (nxfrd != 1)
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{
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fdbg("ERROR: Read block %d failed: %d\n", block, nxfrd);
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return -EIO;
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}
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/* Remember what is in the cache */
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volume->cblock = block;
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}
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return OK;
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}
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/****************************************************************************
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* Name: nxffs_wrcache
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*
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* Description:
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* Write one or more logical blocks from the volume cache memory.
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*
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* Input Parameters:
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* volume - Describes the current volume
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*
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* Returned Value:
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* Negated errnos are returned only in the case of MTD reported failures.
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*
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****************************************************************************/
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int nxffs_wrcache(FAR struct nxffs_volume_s *volume)
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{
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size_t nxfrd;
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/* Write the current block from the cache */
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nxfrd = MTD_BWRITE(volume->mtd, volume->cblock, 1, volume->cache);
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if (nxfrd != 1)
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{
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fdbg("ERROR: Write block %d failed: %d\n", volume->cblock, nxfrd);
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return -EIO;
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}
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/* Write was successful */
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return OK;
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}
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/****************************************************************************
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* Name: nxffs_ioseek
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*
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* Description:
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* Seek to a position in FLASH memory. This simply sets up the offsets
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* and pointer values. This is a necessary step prior to using
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* nxffs_getc().
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*
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* Input Parameters:
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* volume - Describes the NXFFS volume
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* offset - The physical offset in bytes from the beginning of the FLASH
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* in bytes.
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*
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****************************************************************************/
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void nxffs_ioseek(FAR struct nxffs_volume_s *volume, off_t offset)
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{
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/* Convert the offset into a block number and a byte offset into the
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* block.
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*/
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volume->ioblock = offset / volume->geo.blocksize;
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volume->iooffset = offset - volume->geo.blocksize * volume->ioblock;
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}
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/****************************************************************************
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* Name: nxffs_iotell
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*
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* Description:
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* Report the current position.
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*
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* Input Parameters:
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* volume - Describes the NXFFS volume
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*
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* Returned Value:
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* The offset from the beginning of FLASH to the current seek position.
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*
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****************************************************************************/
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off_t nxffs_iotell(FAR struct nxffs_volume_s *volume)
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{
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return volume->ioblock * volume->geo.blocksize + volume->iooffset;
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}
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/****************************************************************************
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* Name: nxffs_getc
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*
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* Description:
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* Get the next byte from FLASH. This function allows the data in the
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* formatted FLASH blocks to be read as a continuous byte stream, skipping
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* over bad blocks and block headers as necessary.
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*
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* Input Parameters:
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* volume - Describes the NXFFS volume. The paramters ioblock and iooffset
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* in the volume structure determine the behavior of nxffs_getc().
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* reserve - If less than this much space is available at the end of the
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* block, then skip to the next block.
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*
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* Returned Value:
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* Zero is returned on success. Otherwise, a negated errno indicating the
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* nature of the failure.
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*
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****************************************************************************/
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int nxffs_getc(FAR struct nxffs_volume_s *volume, uint16_t reserve)
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{
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int ret;
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DEBUGASSERT(reserve > 0);
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/* Loop to skip over bad blocks */
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do
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{
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/* Check if we have the reserve amount at the end of the current block */
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if (volume->iooffset + reserve > volume->geo.blocksize)
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{
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/* Check for attempt to read past the end of FLASH */
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off_t nextblock = volume->ioblock + 1;
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if (nextblock >= volume->nblocks)
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{
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fvdbg("End of FLASH encountered\n");
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return -ENOSPC;
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}
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/* Set up the seek to the data just after the header in the
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* next block.
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*/
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volume->ioblock = nextblock;
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volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR;
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}
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/* Make sure that the block is in the cache. The special error
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* -ENOENT indicates the block was read successfully but was not
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* marked as a good block. In this case we need to skip to the
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* next block. All other errors are fatal.
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*/
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ret = nxffs_verifyblock(volume, volume->ioblock);
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if (ret < 0 && ret != -ENOENT)
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{
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#ifndef CONFIG_NXFFS_NAND
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/* Read errors are fatal */
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fdbg("ERROR: Failed to read valid data into cache: %d\n", ret);
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return ret;
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#else
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/* A read error occurred. This probably means that we are
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* using NAND memory this block has an uncorrectable bit error.
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* Ignore the error (after complaining) and try the next
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* block.
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*/
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fdbg("ERROR: Failed to read valid data into cache: %d\n", ret);
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#endif
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}
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}
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while (ret != OK);
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/* Return the character at this offset. Note that on return,
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* iooffset could point to the byte outside of the current block.
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*/
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ret = (int)volume->cache[volume->iooffset];
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volume->iooffset++;
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return ret;
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}
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