Block-to-character driver

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1235 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 336 insertions, 0 deletions

diff --git a/nuttx/drivers/bch/bchlib_read.c b/nuttx/drivers/bch/bchlib_read.c
new file mode 100644
index 000000000..7af72ce8a
--- /dev/null
+++ b/nuttx/drivers/bch/bchlib_read.c
@@ -0,0 +1,336 @@
+/****************************************************************************
+ * drivers/bch/bchlib_read.c
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Compilation Switches
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/fs.h>
+
+#include "bch_internal.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: bchlib_read
+ *
+ * Description:
+ *   Read from the block device set-up by bchlib_setup as if it were a character
+ *   device.
+ *
+ ****************************************************************************/
+
+ssize_t bchlib_read(FAR void *handle, FAR char *buffer, size_t offset, size_t len)
+{
+  FAR struct bchlib_s *bch;
+  size_t nsectors;
+  size_t sector;
+  uint16 sectoffset;
+  size_t nbytes;
+  size_t bytesread;
+  int    ret;
+
+  /* Get rid of this special case right away */
+
+  if (len < 1)
+    {
+      return 0;
+    }
+
+  /* Convert the file position into a sector number an offset. */
+
+  sector     = offset / bch->sectsize;
+  sectoffset = offset - sector * bch->sectsize;
+
+  if (sector >= bch->nsectors)
+    {
+      /* Return end-of-file */
+
+      return 0;
+    }
+
+  /* Read the initial partial sector */
+
+  bytesread = 0;
+  if (sectoffset > 0)
+    {
+      /* Read the sector into the sector buffer */
+
+      bchlib_readsector(bch, sector);
+
+      /* Copy the tail end of the sector to the user buffer */
+
+      if (sectoffset + len > bch->sectsize)
+        {
+          nbytes = bch->sectsize - sectoffset;
+        }
+      else 
+        {
+          nbytes = len;
+        }
+
+      memcpy(buffer, &bch->buffer[sectoffset], nbytes);
+
+      /* Adjust pointers and counts */
+
+      sectoffset = 0;
+      sector++;
+
+      if (sector >= bch->nsectors)
+        {
+          return nbytes;
+        }
+
+      bytesread  = nbytes;
+      buffer    += nbytes;
+      len       -= nbytes;
+    }
+
+  /* Then read all of the full sectors following the partial sector */
+
+  if (len >= bch->sectsize )
+    {
+      nsectors = len / bch->sectsize;
+      if (sector + nsectors > bch->nsectors)
+        {
+          nsectors = bch->nsectors - sector;
+        }
+
+      ret = bch->inode->u.i_bops->read(bch->inode, bch->buffer, sector, nsectors);
+      if (ret < 0)
+        {
+          fdbg("Read failed: %d\n");
+          return ret;
+        }
+
+      /* Adjust pointers and counts */
+
+      sectoffset = 0;
+      sector    += nsectors;
+
+      nbytes     = nsectors * bch->sectsize;
+      bytesread += nbytes;
+
+      if (sector >= bch->nsectors)
+        {
+          return bytesread;
+        }
+
+      buffer    += nbytes;
+      len       -= nbytes;
+    }
+
+  /* Then read any partial final sector */
+
+  if (len > 0)
+    {
+      /* Read the sector into the sector buffer */
+
+      bchlib_readsector(bch, sector);
+
+      /* Copy the head end of the sector to the user buffer */
+
+      memcpy(buffer, bch->buffer, len);
+
+      /* Adjust counts */
+
+      bytesread += len;
+    }
+
+  return bytesread;
+}
+
+/****************************************************************************
+ * Name: bchlib_write
+ *
+ * Description:
+ *   Write to the block device set-up by bchlib_setup as if it were a character
+ *   device.
+ *
+ ****************************************************************************/
+
+ssize_t bchlib_write(FAR void *handle, FAR const char *buffer, size_t offset, size_t len)
+{
+  FAR struct bchlib_s *bch;
+  size_t nsectors;
+  size_t sector;
+  uint16 sectoffset;
+  size_t nbytes;
+  size_t byteswritten;
+  int    ret;
+
+  /* Get rid of this special case right away */
+
+  if (len < 1)
+    {
+      return 0;
+    }
+
+  /* Convert the file position into a sector number an offset. */
+
+  sector     = offset / bch->sectsize;
+  sectoffset = offset - sector * bch->sectsize;
+
+  if (sector >= bch->nsectors)
+    {
+      return -EFBIG;
+    }
+
+  /* Write the initial partial sector */
+
+  byteswritten = 0;
+  if (sectoffset > 0)
+    {
+      /* Read the full sector into the sector buffer */
+
+      bchlib_readsector(bch, sector);
+
+      /* Copy the tail end of the sector from the user buffer */
+
+      if (sectoffset + len > bch->sectsize)
+        {
+          nbytes = bch->sectsize - sectoffset;
+        }
+      else 
+        {
+          nbytes = len;
+        }
+
+      memcpy(&bch->buffer[sectoffset], buffer, nbytes);
+      bch->dirty = TRUE;
+
+      /* Adjust pointers and counts */
+
+      sectoffset    = 0;
+      sector++;
+
+      if (sector >= bch->nsectors)
+        {
+          return nbytes;
+        }
+
+      byteswritten  = nbytes;
+      buffer       += nbytes;
+      len          -= nbytes;
+    }
+
+  /* Then write all of the full sectors following the partial sector */
+
+  if (len >= bch->sectsize )
+    {
+      nsectors = len / bch->sectsize;
+      if (sector + nsectors > bch->nsectors)
+        {
+          nsectors = bch->nsectors - sector;
+        }
+
+      /* Write the contiguous sectors */
+
+      ret = bch->inode->u.i_bops->write(bch->inode, bch->buffer, sector, nsectors);
+      if (ret < 0)
+        {
+          fdbg("Write failed: %d\n");
+          return ret;
+        }
+
+      /* Adjust pointers and counts */
+
+      sectoffset    = 0;
+      sector       += nsectors;
+
+      nbytes        = nsectors * bch->sectsize;
+      byteswritten += nbytes;
+
+      if (sector >= bch->nsectors)
+        {
+          return byteswritten;
+        }
+
+      buffer    += nbytes;
+      len       -= nbytes;
+    }
+
+  /* Then write any partial final sector */
+
+  if (len > 0)
+    {
+      /* Read the sector into the sector buffer */
+
+      bchlib_readsector(bch, sector);
+
+      /* Copy the head end of the sector from the user buffer */
+
+      memcpy(bch->buffer, buffer, len);
+      bch->dirty = TRUE;
+
+      /* Adjust counts */
+
+      byteswritten += len;
+    }
+
+  return byteswritten;
+}
+