/**************************************************************************** * fs/nxffs/nxffs_cache.c * * Copyright (C) 2011 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #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; }