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+/****************************************************************************
+ * fs/nxffs/nxffs_initialize.c
+ *
+ * Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ * Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * 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 <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/mtd.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/ioctl.h>
+
+#include "nxffs.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Variables
+ ****************************************************************************/
+
+/* See fs_mount.c -- this structure is explicitly externed there.
+ * We use the old-fashioned kind of initializers so that this will compile
+ * with any compiler.
+ */
+
+const struct mountpt_operations nxffs_operations =
+{
+ nxffs_open, /* open */
+ nxffs_close, /* close */
+ nxffs_read, /* read */
+ nxffs_write, /* write */
+ NULL, /* seek -- Use f_pos in struct file */
+ nxffs_ioctl, /* ioctl */
+ NULL, /* sync -- No buffered data */
+
+ nxffs_opendir, /* opendir */
+ NULL, /* closedir */
+ nxffs_readdir, /* readdir */
+ nxffs_rewinddir, /* rewinddir */
+
+ nxffs_bind, /* bind */
+ nxffs_unbind, /* unbind */
+ nxffs_statfs, /* statfs */
+
+ nxffs_unlink, /* unlink */
+ NULL, /* mkdir -- no directories */
+ NULL, /* rmdir -- no directories */
+ NULL, /* rename -- cannot rename in place if name is longer */
+ nxffs_stat /* stat */
+};
+
+/****************************************************************************
+ * Public Variables
+ ****************************************************************************/
+
+/* The magic number that appears that the beginning of each NXFFS (logical)
+ * block
+ */
+
+const uint8_t g_blockmagic[NXFFS_MAGICSIZE] = { 'B', 'l', 'c', 'k' };
+
+/* The magic number that appears that the beginning of each NXFFS inode */
+
+const uint8_t g_inodemagic[NXFFS_MAGICSIZE] = { 'I', 'n', 'o', 'd' };
+
+/* The magic number that appears that the beginning of each NXFFS inode
+ * data block.
+ */
+
+const uint8_t g_datamagic[NXFFS_MAGICSIZE] = { 'D', 'a', 't', 'a' };
+
+/* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
+ * allocated NXFFS volume instance.
+ */
+
+#ifdef CONFIG_NXFSS_PREALLOCATED
+struct nxffs_volume_s g_volume;
+#endif
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: nxffs_initialize
+ *
+ * Description:
+ * Initialize to provide NXFFS on an MTD interface
+ *
+ * Input Parameters:
+ * mtd - The MTD device that supports the FLASH interface.
+ *
+ * Returned Value:
+ * Zero is returned on success. Otherwise, a negated errno value is
+ * returned to indicate the nature of the failure.
+ *
+ ****************************************************************************/
+
+int nxffs_initialize(FAR struct mtd_dev_s *mtd)
+{
+ FAR struct nxffs_volume_s *volume;
+ struct nxffs_blkstats_s stats;
+ off_t threshold;
+ int ret;
+
+ /* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
+ * allocated NXFFS volume instance.
+ */
+
+#ifdef CONFIG_NXFSS_PREALLOCATED
+
+ volume = &g_volume;
+ memset(volume, 0, sizeof(struct nxffs_volume_s));
+
+#else
+
+ /* Allocate a NXFFS volume structure */
+
+ volume = (FAR struct nxffs_volume_s *)kzalloc(sizeof(struct nxffs_volume_s));
+ if (!volume)
+ {
+ ret = -ENOMEM;
+ goto errout;
+ }
+#endif
+
+ /* Initialize the NXFFS volume structure */
+
+ volume->mtd = mtd;
+ volume->cblock = (off_t)-1;
+ sem_init(&volume->exclsem, 0, 1);
+ sem_init(&volume->wrsem, 0, 1);
+
+ /* Get the volume geometry. (casting to uintptr_t first eliminates
+ * complaints on some architectures where the sizeof long is different
+ * from the size of a pointer).
+ */
+
+ ret = MTD_IOCTL(mtd, MTDIOC_GEOMETRY, (unsigned long)((uintptr_t)&volume->geo));
+ if (ret < 0)
+ {
+ fdbg("MTD ioctl(MTDIOC_GEOMETRY) failed: %d\n", -ret);
+ goto errout_with_volume;
+ }
+
+ /* Allocate one I/O block buffer to general files system access */
+
+ volume->cache = (FAR uint8_t *)kmalloc(volume->geo.blocksize);
+ if (!volume->cache)
+ {
+ fdbg("Failed to allocate an erase block buffer\n");
+ ret = -ENOMEM;
+ goto errout_with_volume;
+ }
+
+ /* Pre-allocate one, full, in-memory erase block. This is needed for filesystem
+ * packing (but is useful in other places as well). This buffer is not needed
+ * often, but is best to have pre-allocated and in-place.
+ */
+
+ volume->pack = (FAR uint8_t *)kmalloc(volume->geo.erasesize);
+ if (!volume->pack)
+ {
+ fdbg("Failed to allocate an I/O block buffer\n");
+ ret = -ENOMEM;
+ goto errout_with_cache;
+ }
+
+ /* Get the number of R/W blocks per erase block and the total number o
+ * R/W blocks
+ */
+
+ volume->blkper = volume->geo.erasesize / volume->geo.blocksize;
+ volume->nblocks = volume->geo.neraseblocks * volume->blkper;
+ DEBUGASSERT((off_t)volume->blkper * volume->geo.blocksize == volume->geo.erasesize);
+
+ /* Check if there is a valid NXFFS file system on the flash */
+
+ ret = nxffs_blockstats(volume, &stats);
+ if (ret < 0)
+ {
+ fdbg("Failed to collect block statistics: %d\n", -ret);
+ goto errout_with_buffer;
+ }
+
+ /* If the proportion of good blocks is low or the proportion of unformatted
+ * blocks is high, then reformat the FLASH.
+ */
+
+ threshold = stats.nblocks / 5;
+ if (stats.ngood < threshold || stats.nunformat > threshold)
+ {
+ /* Reformat the volume */
+
+ ret = nxffs_reformat(volume);
+ if (ret < 0)
+ {
+ fdbg("Failed to reformat the volume: %d\n", -ret);
+ goto errout_with_buffer;
+ }
+
+ /* Get statistics on the re-formatted volume */
+
+#if defined(CONFIG_DEBUG) && defined(CONFIG_DEBUG_FS)
+ ret = nxffs_blockstats(volume, &stats);
+ if (ret < 0)
+ {
+ fdbg("Failed to collect block statistics: %d\n", -ret);
+ goto errout_with_buffer;
+ }
+#endif
+ }
+
+ /* Get the file system limits */
+
+ ret = nxffs_limits(volume);
+ if (ret == OK)
+ {
+ return OK;
+ }
+ fdbg("Failed to calculate file system limits: %d\n", -ret);
+
+errout_with_buffer:
+ kfree(volume->pack);
+errout_with_cache:
+ kfree(volume->cache);
+errout_with_volume:
+#ifndef CONFIG_NXFSS_PREALLOCATED
+ kfree(volume);
+#endif
+ return ret;
+}
+
+/****************************************************************************
+ * Name: nxffs_limits
+ *
+ * Description:
+ * Recalculate file system limits: (1) the FLASH offset to the first,
+ * valid inode, and (2) the FLASH offset to the first, unused byte after
+ * the last inode (invalid or not).
+ *
+ * The first, lower limit must be recalculated: (1) initially, (2)
+ * whenever the first inode is deleted, or (3) whenever inode is moved
+ * as part of the file system packing operation.
+ *
+ * The second, upper limit must be (1) incremented whenever new file
+ * data is written, or (2) recalculated as part of the file system packing
+ * operation.
+ *
+ * Input Parameters:
+ * volume - Identifies the NXFFS volume
+ *
+ * Returned Value:
+ * Zero on success. Otherwise, a negated error is returned indicating the
+ * nature of the failure.
+ *
+ ****************************************************************************/
+
+int nxffs_limits(FAR struct nxffs_volume_s *volume)
+{
+ FAR struct nxffs_entry_s entry;
+ off_t block;
+ off_t offset;
+ bool noinodes = false;
+ int nerased;
+ int ret;
+
+ /* Get the offset to the first valid block on the FLASH */
+
+ block = 0;
+ ret = nxffs_validblock(volume, &block);
+ if (ret < 0)
+ {
+ fdbg("Failed to find a valid block: %d\n", -ret);
+ return ret;
+ }
+
+ /* Then find the first valid inode in or beyond the first valid block */
+
+ offset = block * volume->geo.blocksize;
+ ret = nxffs_nextentry(volume, offset, &entry);
+ if (ret < 0)
+ {
+ /* The value -ENOENT is special. This simply means that the FLASH
+ * was searched to the end and no valid inode was found... the file
+ * system is empty (or, in more perverse cases, all inodes are
+ * deleted or corrupted).
+ */
+
+ if (ret != -ENOENT)
+ {
+ fdbg("nxffs_nextentry failed: %d\n", -ret);
+ return ret;
+ }
+
+ /* Set a flag the just indicates that no inodes were found. Later,
+ * we will set the location of the first inode to be the same as
+ * the location of the free FLASH region.
+ */
+
+ fvdbg("No inodes found\n");
+ noinodes = true;
+ }
+ else
+ {
+ /* Save the offset to the first inode */
+
+ volume->inoffset = entry.hoffset;
+ fvdbg("First inode at offset %d\n", volume->inoffset);
+
+ /* Discard this entry and set the next offset. */
+
+ offset = nxffs_inodeend(volume, &entry);
+ nxffs_freeentry(&entry);
+ }
+
+ /* Now, search for the last valid entry */
+
+ if (!noinodes)
+ {
+ while ((ret = nxffs_nextentry(volume, offset, &entry)) == OK)
+ {
+ /* Discard the entry and guess the next offset. */
+
+ offset = nxffs_inodeend(volume, &entry);
+ nxffs_freeentry(&entry);
+ }
+ fvdbg("Last inode before offset %d\n", offset);
+ }
+
+ /* No inodes were found after this offset. Now search for a block of
+ * erased flash.
+ */
+
+ nxffs_ioseek(volume, offset);
+ nerased = 0;
+ for (;;)
+ {
+ int ch = nxffs_getc(volume, 1);
+ if (ch < 0)
+ {
+ /* Failed to read the next byte... this could mean that the FLASH
+ * is full?
+ */
+
+ if (volume->ioblock + 1 >= volume->nblocks &&
+ volume->iooffset + 1 >= volume->geo.blocksize)
+ {
+ /* Yes.. the FLASH is full. Force the offsets to the end of FLASH */
+
+ volume->froffset = volume->nblocks * volume->geo.blocksize;
+ fvdbg("Assume no free FLASH, froffset: %d\n", volume->froffset);
+ if (noinodes)
+ {
+ volume->inoffset = volume->froffset;
+ fvdbg("No inodes, inoffset: %d\n", volume->inoffset);
+ }
+ return OK;
+ }
+
+ // No? Then it is some other failure that we do not know how to handle
+
+ fdbg("nxffs_getc failed: %d\n", -ch);
+ return ch;
+ }
+
+ /* Check for another erased byte */
+
+ else if (ch == CONFIG_NXFFS_ERASEDSTATE)
+ {
+ /* If we have encountered NXFFS_NERASED number of consecutive
+ * erased bytes, then presume we have reached the end of valid
+ * data.
+ */
+
+ if (++nerased >= NXFFS_NERASED)
+ {
+ /* Okay.. we have a long stretch of erased FLASH in a valid
+ * FLASH block. Let's say that this is the beginning of
+ * the free FLASH region.
+ */
+
+ volume->froffset = offset;
+ fvdbg("Free FLASH region begins at offset: %d\n", volume->froffset);
+ if (noinodes)
+ {
+ volume->inoffset = offset;
+ fvdbg("First inode at offset %d\n", volume->inoffset);
+ }
+ return OK;
+ }
+ }
+ else
+ {
+ offset += nerased + 1;
+ nerased = 0;
+ }
+ }
+
+ /* Won't get here */
+
+ return OK;
+}
+
+/****************************************************************************
+ * Name: nxffs_bind
+ *
+ * Description:
+ * This function implements a portion of the mount operation. Normmally,
+ * the bind() method allocates and initializes the mountpoint private data
+ * then binds the blockdriver inode to the filesystem private data. The
+ * final binding of the private data (containing the blockdriver) to the
+ * mountpoint is performed by mount().
+ *
+ * For the NXFFS, this sequence is quite different for the following
+ * reasons:
+ *
+ * 1. A block driver is not used. Instead, an MTD instance was provided
+ * to nxfs_initialize prior to mounting. So, in this sense, the NXFFS
+ * file system is already bound.
+ *
+ * 2. Since the volume was already bound to the MTD driver, all allocations
+ * and initializations have already been performed. Essentially, all
+ * mount operations have been bypassed and now we just need to provide
+ * the pre-allocated volume instance.
+ *
+ * 3. The tricky thing is that there is no mechanism to associate multiple
+ * NXFFS volumes to the multiple volumes bound to different MTD drivers.
+ * Hence, the limitation of a single NXFFS volume.
+ *
+ ****************************************************************************/
+
+int nxffs_bind(FAR struct inode *blkdriver, FAR const void *data,
+ FAR void **handle)
+{
+#ifndef CONFIG_NXFSS_PREALLOCATED
+# error "No design to support dynamic allocation of volumes"
+#else
+
+ /* If CONFIG_NXFSS_PREALLOCATED is defined, then this is the single, pre-
+ * allocated NXFFS volume instance.
+ */
+
+ DEBUGASSERT(g_volume.cache);
+ *handle = &g_volume;
+#endif
+ return OK;
+}
+
+/****************************************************************************
+ * Name: nxffs_unbind
+ *
+ * Description: This implements the filesystem portion of the umount
+ * operation.
+ *
+ ****************************************************************************/
+
+int nxffs_unbind(FAR void *handle, FAR struct inode **blkdriver)
+{
+#ifndef CONFIG_NXFSS_PREALLOCATED
+# error "No design to support dynamic allocation of volumes"
+#else
+ return g_volume.ofiles ? -EBUSY : OK;
+#endif
+}
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