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;
+}