diff --git a/ChangeLog b/ChangeLog
index f63acc0665cd5c30aa5925db28c4cfd9da30f559..0788d88dac6e62837d058f1d0a33e012323af9f6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -985,4 +985,9 @@
* arch/hc: Adding framework to support m68hc11/12
* configs/demo9s12ne64: Configuration to support Freescale DEMO9S12NE64
development board (MC9S12NE64 m68hcs12 processor).
+ * drivers/mtd/ftl.c - A FLASH translation layer (FTL) has been implemented.
+ This layer will convert a FLASH MTD interface into a block driver that
+ can be used with any file system. Good performance of this layer will
+ depend upon functioning write buffer support!
+ NOTE: FTL support is untested as of the initial check-in.
diff --git a/Documentation/NuttX.html b/Documentation/NuttX.html
index cd2121d84a2bea693708b2f985f24d191bdc1626..00b100abb0088a696e8fac3eddd66e7ac887b56b 100644
--- a/Documentation/NuttX.html
+++ b/Documentation/NuttX.html
@@ -8,7 +8,7 @@
<tr align="center" bgcolor="#e4e4e4">
<td>
<h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
- <p>Last Updated: December 3, 2009</p>
+ <p>Last Updated: December 5 2009</p>
</td>
</tr>
</table>
@@ -1611,6 +1611,11 @@ nuttx-2010.1 2010-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
* arch/hc: Adding framework to support m68hc11/12
* configs/demo9s12ne64: Configuration to support Freescale DEMO9S12NE64
development board (MC9S12NE64 m68hcs12 processor).
+ * drivers/mtd/ftl.c - A FLASH translation layer (FTL) has been implemented.
+ This layer will convert a FLASH MTD interface into a block driver that
+ can be used with any file system. Good performance of this layer will
+ depend upon functioning write buffer support!
+ NOTE: FTL support is untested as of the initial check-in.
pascal-2010.1 2010-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
diff --git a/TODO b/TODO
index cf890b0f24335915d2fbd2f40dc3998dfe9f6490..9fab0128894f39a5d0c6c80d0f6f0bfbda954e3e 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,4 @@
-NuttX TODO List (Last updated November 29, 2009)
+NuttX TODO List (Last updated December 5, 2009)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(5) Task/Scheduler (sched/)
@@ -11,7 +11,7 @@ NuttX TODO List (Last updated November 29, 2009)
(4) Network Utilities (netutils/)
(1) USB (drivers/usbdev)
(5) Libraries (lib/)
- (8) File system/Generic drivers (fs/, drivers/)
+ (11) File system/Generic drivers (fs/, drivers/)
(2) Graphics subystem (graphics/)
(1) Pascal add-on (pcode/)
(1) Documentation (Documentation/)
@@ -359,6 +359,25 @@ o File system / Generic drivers (fs/, drivers/)
Status: Open
Priority: Low
+ Description: Block driver read-ahead buffer and write buffer support is
+ implemented but not yet tested.
+ Status: Open
+ Priority: Low
+
+ Description: The drivers/mmcsd/mmcsd_sdio.c driver has hooks in place to
+ support read-ahead buffering and write buffering, but the logic
+ is incomplete and untested.
+ Status: Open
+ Priority: Low
+
+ Description: A FLASH translation layer (FTL) has been implemented at
+ drivers/mtd/ftl.c but has not yet been tested. This layer
+ will convert a FLASH MTD interface into a block driver that
+ can be used with any file system. Good performance of this
+ layer will depend upon functioning write buffer support!
+ Status: Open
+ Priority: Low
+
o Graphics subystem (graphics/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/drivers/mtd/Make.defs b/drivers/mtd/Make.defs
index ff5b0a225878ee94fde8dcd5c8d0419aab261b5f..9fb5846586e6441e8659fc10069ad30d5f8c515c 100644
--- a/drivers/mtd/Make.defs
+++ b/drivers/mtd/Make.defs
@@ -34,5 +34,5 @@
############################################################################
MTD_ASRCS =
-MTD_CSRCS = m25px.c
+MTD_CSRCS = ftl.c m25px.c
diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c
new file mode 100755
index 0000000000000000000000000000000000000000..08fa942037d54a9aa4646c1d6e603d3e6b9797f0
--- /dev/null
+++ b/drivers/mtd/ftl.c
@@ -0,0 +1,542 @@
+/****************************************************************************
+ * drivers/mtd/ftl.c
+ *
+ * Copyright (C) 2009 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <debug.h>
+#include <errno.h>
+
+#include <nuttx/fs.h>
+#include <nuttx/ioctl.h>
+#include <nuttx/mtd.h>
+#include <nuttx/rwbuffer.h>
+
+/****************************************************************************
+ * Private Definitions
+ ****************************************************************************/
+
+#if defined(CONFIG_FS_READAHEAD) || (defined(CONFIG_FS_WRITABLE) && defined(CONFIG_FS_WRITEBUFFER))
+# defined CONFIG_FTL_RWBUFFER 1
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct ftl_struct_s
+{
+ FAR struct mtd_dev_s *mtd; /* Contained MTD interface */
+ struct mtd_geometry_s geo; /* Device geometry */
+#ifdef CONFIG_FTL_RWBUFFER
+ struct rwbuffer_s rwb; /* Read-ahead/write buffer support */
+#endif
+ uint16 blkper; /* R/W blocks per erase block */
+#ifdef CONFIG_FS_WRITABLE
+ FAR ubyte *eblock; /* One, in-memory erase block */
+#endif
+};
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int ftl_open(FAR struct inode *inode);
+static int ftl_close(FAR struct inode *inode);
+static ssize_t ftl_reload(FAR void *priv, FAR ubyte *buffer,
+ off_t startblock, size_t nblocks);
+static ssize_t ftl_read(FAR struct inode *inode, unsigned char *buffer,
+ size_t start_sector, unsigned int nsectors);
+#ifdef CONFIG_FS_WRITABLE
+static ssize_t ftl_flush(FAR void *priv, FAR const ubyte *buffer,
+ off_t startblock, size_t nblocks);
+static ssize_t ftl_write(FAR struct inode *inode, const unsigned char *buffer,
+ size_t start_sector, unsigned int nsectors);
+#endif
+static int ftl_geometry(FAR struct inode *inode, struct geometry *geometry);
+static int ftl_ioctl(FAR struct inode *inode, int cmd, unsigned long arg);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct block_operations g_bops =
+{
+ ftl_open, /* open */
+ ftl_close, /* close */
+ ftl_read, /* read */
+#ifdef CONFIG_FS_WRITABLE
+ ftl_write, /* write */
+#else
+ NULL, /* write */
+#endif
+ ftl_geometry, /* geometry */
+ ftl_ioctl /* ioctl */
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ftl_open
+ *
+ * Description: Open the block device
+ *
+ ****************************************************************************/
+
+static int ftl_open(FAR struct inode *inode)
+{
+ fvdbg("Entry\n");
+ return OK;
+}
+
+/****************************************************************************
+ * Name: ftl_closel
+ *
+ * Description: close the block device
+ *
+ ****************************************************************************/
+
+static int ftl_close(FAR struct inode *inode)
+{
+ fvdbg("Entry\n");
+ return OK;
+}
+
+/****************************************************************************
+ * Name: ftl_reload
+ *
+ * Description: Read the specified numer of sectors
+ *
+ ****************************************************************************/
+
+static ssize_t ftl_reload(FAR void *priv, FAR ubyte *buffer,
+ off_t startblock, size_t nblocks)
+{
+ struct ftl_struct_s *dev = (struct ftl_struct_s *)priv;
+ ssize_t nread;
+
+ /* Read the full erase block into the buffer */
+
+ nread = MTD_BREAD(dev->mtd, startblock, nblocks, buffer);
+ if (nread != nblocks)
+ {
+ fdbg("Read %d blocks starting at block %d failed: %d\n",
+ nblocks, startblock, nread);
+ }
+ return nread;
+}
+
+/****************************************************************************
+ * Name: ftl_read
+ *
+ * Description: Read the specified numer of sectors
+ *
+ ****************************************************************************/
+
+static ssize_t ftl_read(FAR struct inode *inode, unsigned char *buffer,
+ size_t start_sector, unsigned int nsectors)
+{
+ struct ftl_struct_s *dev;
+
+ fvdbg("sector: %d nsectors: %d sectorsize: %d\n");
+
+ DEBUGASSERT(inode && inode->i_private);
+ dev = (struct ftl_struct_s *)inode->i_private;
+#ifdef CONFIG_FS_READAHEAD
+ return rwb_read(&dev->rwb, start_sector, nsectors, buffer);
+#else
+ return ftl_reload(dev, buffer, start_sector, nsectors);
+#endif
+}
+
+/****************************************************************************
+ * Name: ftl_write
+ *
+ * Description: Write the specified number of sectors
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_FS_WRITABLE
+static ssize_t ftl_flush(FAR void *priv, FAR const ubyte *buffer,
+ off_t startblock, size_t nblocks)
+{
+ struct ftl_struct_s *dev = (struct ftl_struct_s *)priv;
+ off_t alignedblock;
+ off_t mask;
+ off_t rwblock;
+ off_t eraseblock;
+ off_t offset;
+ size_t remaining;
+ size_t nxfrd;
+ int nbytes;
+ int ret;
+
+ /* Get the aligned block. Here is is assumed: (1) The number of R/W blocks
+ * per erase block is a power of 2, and (2) the erase begins with that same
+ * alignment.
+ */
+
+ mask = dev->blkper - 1;
+ alignedblock = (startblock + mask) & ~mask;
+
+ /* Handle partial erase blocks before the first unaligned block */
+
+ remaining = nblocks;
+ if (alignedblock > startblock)
+ {
+ /* Read the full erase block into the buffer */
+
+ rwblock = startblock & ~mask;
+ nxfrd = MTD_BREAD(dev->mtd, rwblock, dev->blkper, dev->eblock);
+ if (nxfrd != dev->blkper)
+ {
+ fdbg("Read erase block %d failed: %d\n", rwblock, nxfrd);
+ return -EIO;
+ }
+
+ /* Then erase the erase block */
+
+ eraseblock = rwblock / dev->blkper;
+ ret = MTD_ERASE(dev->mtd, eraseblock, 1);
+ if (ret < 0)
+ {
+ fdbg("Erase block=%d failed: %d\n", eraseblock, ret);
+ return ret;
+ }
+
+ /* Copy the user data at the end of the buffered erase block */
+
+ offset = (startblock & mask) * dev->geo.blocksize;
+ nbytes = dev->geo.erasesize - offset;
+ fvdbg("Copy %d bytes into erase block=%d at offset=%d\n",
+ nbytes, eraseblock, offset);
+ memcpy(dev->eblock + offset, buffer, nbytes);
+
+ /* And write the erase back to flash */
+
+ nxfrd = MTD_BWRITE(dev->mtd, rwblock, dev->blkper, dev->eblock);
+ if (nxfrd != dev->blkper)
+ {
+ fdbg("Write erase block %d failed: %d\n", rwblock, nxfrd);
+ return -EIO;
+ }
+
+ /* Then update for amount written */
+
+ remaining -= dev->blkper - (startblock & mask);
+ buffer += nbytes;
+ }
+
+ /* How handle full erase pages in the middle */
+
+ while (remaining >= dev->blkper)
+ {
+ /* Erase the erase block */
+
+ eraseblock = alignedblock / dev->blkper;
+ ret = MTD_ERASE(dev->mtd, eraseblock, 1);
+ if (ret < 0)
+ {
+ fdbg("Erase block=%d failed: %d\n", eraseblock, ret);
+ return ret;
+ }
+
+ /* Write a full erase back to flash */
+
+ fvdbg("Write %d bytes into erase block=%d at offset=0\n",
+ dev->geo.erasesize, alignedblock);
+ nxfrd = MTD_BWRITE(dev->mtd, alignedblock, dev->blkper, buffer);
+ if (nxfrd != dev->blkper)
+ {
+ fdbg("Write erase block %d failed: %d\n", , alignedblock, nxfrd);
+ return -EIO;
+ }
+
+ /* Then update for amount written */
+
+ alignedblock += dev->blkper;
+ remaining -= dev->blkper;
+ buffer += dev->geo.erasesize;
+ }
+
+ /* Finally, handler any partial blocks after the last full erase block */
+
+ if (remaining > 0)
+ {
+ /* Read the full erase block into the buffer */
+
+ nxfrd = MTD_BREAD(dev->mtd, alignedblock, dev->blkper, dev->eblock);
+ if (nxfrd != dev->blkper)
+ {
+ fdbg("Read erase block %d failed: %d\n", alignedblock, nxfrd);
+ return -EIO;
+ }
+
+ /* Then erase the erase block */
+
+ eraseblock = alignedblock / dev->blkper;
+ ret = MTD_ERASE(dev->mtd, eraseblock, 1);
+ if (ret < 0)
+ {
+ fdbg("Erase block=%d failed: %d\n", eraseblock, ret);
+ return ret;
+ }
+
+ /* Copy the user data at the beginning the buffered erase block */
+
+ nbytes = remaining * dev->geo.blocksize;
+ fvdbg("Copy %d bytes into erase block=%d at offset=0\n",
+ nbytes, alignedblock);
+ memcpy(dev->eblock, buffer, nbytes);
+
+ /* And write the erase back to flash */
+
+ nxfrd = MTD_BWRITE(dev->mtd, alignedblock, dev->blkper, dev->eblock);
+ if (nxfrd != dev->blkper)
+ {
+ fdbg("Write erase block %d failed: %d\n", alignedblock, nxfrd);
+ return -EIO;
+ }
+ }
+
+ return nblocks;
+}
+#endif
+
+/****************************************************************************
+ * Name: ftl_write
+ *
+ * Description: Write (or buffer) the specified number of sectors
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_FS_WRITABLE
+static ssize_t ftl_write(FAR struct inode *inode, const unsigned char *buffer,
+ size_t start_sector, unsigned int nsectors)
+{
+ struct ftl_struct_s *dev;
+
+ fvdbg("sector: %d nsectors: %d sectorsize: %d\n");
+
+ DEBUGASSERT(inode && inode->i_private);
+ dev = (struct ftl_struct_s *)inode->i_private;
+#ifdef CONFIG_FS_WRITEBUFFER
+ return rwb_write(&dev->rwb, start_sector, nsectors, buffer);
+#else
+ return ftl_flush(dev, buffer, start_sector, nsectors);
+#endif
+}
+#endif
+
+/****************************************************************************
+ * Name: ftl_geometry
+ *
+ * Description: Return device geometry
+ *
+ ****************************************************************************/
+
+static int ftl_geometry(FAR struct inode *inode, struct geometry *geometry)
+{
+ struct ftl_struct_s *dev;
+
+ fvdbg("Entry\n");
+
+ DEBUGASSERT(inode);
+ if (geometry)
+ {
+ dev = (struct ftl_struct_s *)inode->i_private;
+ geometry->geo_available = TRUE;
+ geometry->geo_mediachanged = FALSE;
+#ifdef CONFIG_FS_WRITABLE
+ geometry->geo_writeenabled = TRUE;
+#else
+ geometry->geo_writeenabled = FALSE;
+#endif
+ geometry->geo_nsectors = dev->geo.neraseblocks * dev->blkper;
+ geometry->geo_sectorsize = dev->geo.blocksize;
+
+ fvdbg("available: TRUE mediachanged: FALSE writeenabled: %s\n",
+ geometry->geo_writeenabled ? "TRUE" : "FALSE");
+ fvdbg("nsectors: %d sectorsize: %d\n",
+ geometry->geo_nsectors, geometry->geo_sectorsize);
+
+ return OK;
+ }
+ return -EINVAL;
+}
+
+/****************************************************************************
+ * Name: ftl_ioctl
+ *
+ * Description: Return device geometry
+ *
+ ****************************************************************************/
+
+static int ftl_ioctl(FAR struct inode *inode, int cmd, unsigned long arg)
+{
+ struct ftl_struct_s *dev ;
+ int ret = -ENOTTY;
+
+ fvdbg("Entry\n");
+
+ /* Only one ioctl command is supported (and that is just passed on to MTD */
+
+ DEBUGASSERT(inode && inode->i_private);
+ if (cmd == BIOC_XIPBASE && arg != 0)
+ {
+ dev = (struct ftl_struct_s *)inode->i_private;
+ ret = MTD_IOCTL(dev->mtd, MTDIOC_XIPBASE, arg);
+ if (ret < 0)
+ {
+ fdbg("MTD ioctl(MTDIOC_XIPBASE) failed: %d\n", ret);
+ }
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ftl_initialize
+ *
+ * Description:
+ * Initialize to provide a block driver wrapper around an MTD interface
+ *
+ ****************************************************************************/
+
+int ftl_initialize(int minor, ubyte *buffer, FAR struct mtd_dev_s *mtd)
+{
+ struct ftl_struct_s *dev;
+ char devname[16];
+ int ret = -ENOMEM;
+
+ /* Sanity check */
+
+#ifdef CONFIG_DEBUG
+ if (minor < 0 || minor > 255 || !mtd)
+ {
+ return -EINVAL;
+ }
+#endif
+
+ /* Allocate a ramdisk device structure */
+
+ dev = (struct ftl_struct_s *)malloc(sizeof(struct ftl_struct_s));
+ if (dev)
+ {
+ /* Initialize the ramdisk device structure */
+
+ dev->mtd = mtd;
+
+ /* Get the device geometry */
+
+ ret = MTD_IOCTL(mtd, MTDIOC_GEOMETRY, (unsigned long)&dev->geo);
+ if (ret < 0)
+ {
+ fdbg("MTD ioctl(MTDIOC_GEOMETRY) failed: %d\n", ret);
+ free(dev);
+ return ret;
+ }
+
+ /* Allocate one, in-memory erase block buffer */
+
+#ifdef CONFIG_FS_WRITABLE
+ dev->eblock = (FAR ubyte *)malloc(dev->geo.erasesize);
+ if (!dev->eblock)
+ {
+ fdbg("Failed to allocate an erase block buffer\n");
+ free(dev);
+ return -ENOMEM;
+ }
+#endif
+
+ /* Get the number of R/W blocks per erase block */
+
+ dev->blkper = dev->geo.erasesize / dev->geo.blocksize;
+ DEBUGASSERT(dev->blkper * dev->geo.blocksize = dev->geo.erasesize);
+
+ /* Configure read-ahead/write buffering */
+
+#ifdef CONFIG_FTL_RWBUFFER
+ dev->rwb.blocksize = dev->geo.blocksize;
+ dev->rwb.nblocks = dev->geo.neraseblocks * dev->blkper;
+ dev->rwb.dev = (FAR void *)dev;
+
+#ifdef defined(CONFIG_FS_WRITABLE) && defined(CONFIG_FS_WRITEBUFFER)
+ dev->rwb.wrmaxblocks = dev->blkper;
+ dev->rwb.wrflush = ftl_flush;
+#endif
+
+#ifdef CONFIG_FS_READAHEAD
+ dev->rwb.rhmaxblocks = dev->blkper;
+ dev->rwb.rhreload = ftl_reload;
+#endif
+ ret = rwb_initialize(&dev->rwb);
+ if (ret < 0)
+ {
+ fdbg("rwb_initialize failed: %d\n", ret);
+ free(dev);
+ return ret;
+ }
+#endif
+
+ /* Create a MTD block device name */
+
+ snprintf(devname, 16, "/dev/mtdblock%d", minor);
+
+ /* Inode private data is a reference to the ramdisk device stgructure */
+
+ ret = register_blockdriver(devname, &g_bops, 0, dev);
+ if (ret < 0)
+ {
+ fdbg("register_blockdriver failed: %d\n", -ret);
+ free(dev);
+ }
+ }
+ return ret;
+}
diff --git a/include/nuttx/mtd.h b/include/nuttx/mtd.h
index 494baec67f4217af4847002abde1cd43e09e3595..2e1b137acbf612adc03bedc215e3f88255c4315d 100644
--- a/include/nuttx/mtd.h
+++ b/include/nuttx/mtd.h
@@ -71,7 +71,7 @@ struct mtd_geometry_s
uint16 blocksize; /* Size of one read/write block */
uint16 erasesize; /* Size of one erase blocks -- must be a multiple
* of blocksize. */
- size_t neraseblocks; /* Number of erase blocks */
+ size_t neraseblocks; /* Number of erase blocks */
};
/* This structure defines the interface to a simple memory technology device.
@@ -83,7 +83,7 @@ struct mtd_dev_s
{
/* The following methods operate on the MTD: */
- /* Erase the specified erase blocks */
+ /* Erase the specified erase blocks (units are erase blocks) */
int (*erase)(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks);
diff --git a/include/nuttx/rwbuffer.h b/include/nuttx/rwbuffer.h
index da97ac505337ae638bf7949d737d0529e9b14049..2ea525ce7f9781e43e41c3b682b281c3f5bdf9cd 100644
--- a/include/nuttx/rwbuffer.h
+++ b/include/nuttx/rwbuffer.h
@@ -106,7 +106,7 @@ struct rwbuffer_s
uint16 blocksize; /* The size of one block */
size_t nblocks; /* The total number blocks supported */
- void *dev; /* Device state passed to callout functions */
+ FAR void *dev; /* Device state passed to callout functions */
/* Write buffer setup. If CONFIG_FS_WRITEBUFFER is defined, but you
* want read-ahead-only operation, (1) set wrmaxblocks to zero and do