diff options
Diffstat (limited to 'nuttx/fs/nxffs/nxffs_cache.c')
-rw-r--r-- | nuttx/fs/nxffs/nxffs_cache.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/nuttx/fs/nxffs/nxffs_cache.c b/nuttx/fs/nxffs/nxffs_cache.c new file mode 100644 index 000000000..5c5cbaa18 --- /dev/null +++ b/nuttx/fs/nxffs/nxffs_cache.c @@ -0,0 +1,261 @@ +/**************************************************************************** + * fs/nxffs/nxffs_cache.c + * + * Copyright (C) 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * References: Linux/Documentation/filesystems/romfs.txt + * + * 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 + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <assert.h> +#include <errno.h> +#include <debug.h> + +#include <nuttx/mtd.h> + +#include "nxffs.h" + +/**************************************************************************** + * Pre-processor Definitions + ****************************************************************************/ + +/**************************************************************************** + * Public Types + ****************************************************************************/ + +/**************************************************************************** + * Public Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: nxffs_rdcache + * + * Description: + * Read one I/O block into the volume block cache memory. + * + * Input Parameters: + * volume - Describes the current volume + * block - The first logical block to read + * + * Returned Value: + * Negated errnos are returned only in the case of MTD reported failures. + * Nothing in the volume data itself will generate errors. + * + ****************************************************************************/ + +int nxffs_rdcache(FAR struct nxffs_volume_s *volume, off_t block) +{ + size_t nxfrd; + + /* Check if the requested data is already in the cache */ + + if (block != volume->cblock) + { + /* Read the specified blocks into cache */ + + nxfrd = MTD_BREAD(volume->mtd, block, 1, volume->cache); + if (nxfrd != 1) + { + fvdbg("Read block %d failed: %d\n", block, nxfrd); + return -EIO; + } + + /* Remember what is in the cache */ + + volume->cblock = block; + } + return OK; +} + +/**************************************************************************** + * Name: nxffs_wrcache + * + * Description: + * Write one or more logical blocks from the volume cache memory. + * + * Input Parameters: + * volume - Describes the current volume + * + * Returned Value: + * Negated errnos are returned only in the case of MTD reported failures. + * + ****************************************************************************/ + +int nxffs_wrcache(FAR struct nxffs_volume_s *volume) +{ + size_t nxfrd; + + /* Write the current block from the cache */ + + nxfrd = MTD_BWRITE(volume->mtd, volume->cblock, 1, volume->cache); + if (nxfrd != 1) + { + fdbg("Write block %d failed: %d\n", volume->cblock, nxfrd); + return -EIO; + } + + /* Write was successful */ + + return OK; +} + +/**************************************************************************** + * Name: nxffs_ioseek + * + * Description: + * Seek to a position in FLASH memory. This simply sets up the offsets + * and pointer values. This is a necessary step prior to using + * nxffs_getc(). + * + * Input Parameters: + * volume - Describes the NXFFS volume + * offset - The physical offset in bytes from the beginning of the FLASH + * in bytes. + * + ****************************************************************************/ + +void nxffs_ioseek(FAR struct nxffs_volume_s *volume, off_t offset) +{ + /* Convert the offset into a block number and a byte offset into the + * block. + */ + + volume->ioblock = offset / volume->geo.blocksize; + volume->iooffset = offset - volume->geo.blocksize * volume->ioblock; +} + +/**************************************************************************** + * Name: nxffs_iotell + * + * Description: + * Report the current position. + * + * Input Parameters: + * volume - Describes the NXFFS volume + * + * Returned Value: + * The offset from the beginning of FLASH to the current seek position. + * + ****************************************************************************/ + +off_t nxffs_iotell(FAR struct nxffs_volume_s *volume) +{ + return volume->ioblock * volume->geo.blocksize + volume->iooffset; +} + +/**************************************************************************** + * Name: nxffs_getc + * + * Description: + * Get the next byte from FLASH. This function allows the data in the + * formatted FLASH blocks to be read as a continuous byte stream, skipping + * over bad blocks and block headers as necessary. + * + * Input Parameters: + * volume - Describes the NXFFS volume. The paramters ioblock and iooffset + * in the volume structure determine the behavior of nxffs_getc(). + * reserve - If less than this much space is available at the end of the + * block, then skip to the next block. + * + * Returned Value: + * Zero is returned on success. Otherwise, a negated errno indicating the + * nature of the failure. + * + ****************************************************************************/ + +int nxffs_getc(FAR struct nxffs_volume_s *volume, uint16_t reserve) +{ + int ret; + + DEBUGASSERT(reserve > 0); + + /* Loop to skip over bad blocks */ + + do + { + /* Check if we have the reserve amount at the end of the current block */ + + if (volume->iooffset + reserve > volume->geo.blocksize) + { + /* Check for attempt to read past the end of FLASH */ + + off_t nextblock = volume->ioblock + 1; + if (nextblock >= volume->nblocks) + { + fvdbg("End of FLASH encountered\n"); + return -ENOSPC; + } + + /* Set up the seek to the data just after the header in the + * next block. + */ + + volume->ioblock = nextblock; + volume->iooffset = SIZEOF_NXFFS_BLOCK_HDR; + } + + /* Make sure that the block is in the cache. The special error + * -ENOENT indicates the block was read successfully but was not + * marked as a good block. In this case we need to skip to the + * next block. All other errors are fatal. + */ + + ret = nxffs_verifyblock(volume, volume->ioblock); + if (ret < 0 && ret != -ENOENT) + { + fvdbg("Failed to read valid data into cache: %d\n", ret); + return ret; + } + } + while (ret != OK); + + /* Return the the character at this offset. Note that on return, + * iooffset could point to the byte outside of the current block. + */ + + ret = (int)volume->cache[volume->iooffset]; + volume->iooffset++; + return ret; +} |