Adding upstream version 5.10.209.upstream/5.10.209

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1075 insertions, 0 deletions

diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c
new file mode 100644
index 000000000..2578f2791
--- /dev/null
+++ b/drivers/mtd/ftl.c
@@ -0,0 +1,1075 @@
+/* This version ported to the Linux-MTD system by dwmw2@infradead.org
+ *
+ * Fixes: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ * - fixes some leaks on failure in build_maps and ftl_notify_add, cleanups
+ *
+ * Based on:
+ */
+/*======================================================================
+
+    A Flash Translation Layer memory card driver
+
+    This driver implements a disk-like block device driver with an
+    apparent block size of 512 bytes for flash memory cards.
+
+    ftl_cs.c 1.62 2000/02/01 00:59:04
+
+    The contents of this file are subject to the Mozilla Public
+    License Version 1.1 (the "License"); you may not use this file
+    except in compliance with the License. You may obtain a copy of
+    the License at http://www.mozilla.org/MPL/
+
+    Software distributed under the License is distributed on an "AS
+    IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+    implied. See the License for the specific language governing
+    rights and limitations under the License.
+
+    The initial developer of the original code is David A. Hinds
+    <dahinds@users.sourceforge.net>.  Portions created by David A. Hinds
+    are Copyright © 1999 David A. Hinds.  All Rights Reserved.
+
+    Alternatively, the contents of this file may be used under the
+    terms of the GNU General Public License version 2 (the "GPL"), in
+    which case the provisions of the GPL are applicable instead of the
+    above.  If you wish to allow the use of your version of this file
+    only under the terms of the GPL and not to allow others to use
+    your version of this file under the MPL, indicate your decision
+    by deleting the provisions above and replace them with the notice
+    and other provisions required by the GPL.  If you do not delete
+    the provisions above, a recipient may use your version of this
+    file under either the MPL or the GPL.
+
+    LEGAL NOTE: The FTL format is patented by M-Systems.  They have
+    granted a license for its use with PCMCIA devices:
+
+     "M-Systems grants a royalty-free, non-exclusive license under
+      any presently existing M-Systems intellectual property rights
+      necessary for the design and development of FTL-compatible
+      drivers, file systems and utilities using the data formats with
+      PCMCIA PC Cards as described in the PCMCIA Flash Translation
+      Layer (FTL) Specification."
+
+    Use of the FTL format for non-PCMCIA applications may be an
+    infringement of these patents.  For additional information,
+    contact M-Systems directly. M-Systems since acquired by Sandisk. 
+
+======================================================================*/
+#include <linux/mtd/blktrans.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+/*#define PSYCHO_DEBUG */
+
+#include <linux/kernel.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/major.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/hdreg.h>
+#include <linux/vmalloc.h>
+#include <linux/blkpg.h>
+#include <linux/uaccess.h>
+
+#include <linux/mtd/ftl.h>
+
+/*====================================================================*/
+
+/* Parameters that can be set with 'insmod' */
+static int shuffle_freq = 50;
+module_param(shuffle_freq, int, 0);
+
+/*====================================================================*/
+
+/* Major device # for FTL device */
+#ifndef FTL_MAJOR
+#define FTL_MAJOR	44
+#endif
+
+
+/*====================================================================*/
+
+/* Maximum number of separate memory devices we'll allow */
+#define MAX_DEV		4
+
+/* Maximum number of regions per device */
+#define MAX_REGION	4
+
+/* Maximum number of partitions in an FTL region */
+#define PART_BITS	4
+
+/* Maximum number of outstanding erase requests per socket */
+#define MAX_ERASE	8
+
+/* Sector size -- shouldn't need to change */
+#define SECTOR_SIZE	512
+
+
+/* Each memory region corresponds to a minor device */
+typedef struct partition_t {
+    struct mtd_blktrans_dev mbd;
+    uint32_t		state;
+    uint32_t		*VirtualBlockMap;
+    uint32_t		FreeTotal;
+    struct eun_info_t {
+	uint32_t		Offset;
+	uint32_t		EraseCount;
+	uint32_t		Free;
+	uint32_t		Deleted;
+    } *EUNInfo;
+    struct xfer_info_t {
+	uint32_t		Offset;
+	uint32_t		EraseCount;
+	uint16_t		state;
+    } *XferInfo;
+    uint16_t		bam_index;
+    uint32_t		*bam_cache;
+    uint16_t		DataUnits;
+    uint32_t		BlocksPerUnit;
+    erase_unit_header_t	header;
+} partition_t;
+
+/* Partition state flags */
+#define FTL_FORMATTED	0x01
+
+/* Transfer unit states */
+#define XFER_UNKNOWN	0x00
+#define XFER_ERASING	0x01
+#define XFER_ERASED	0x02
+#define XFER_PREPARED	0x03
+#define XFER_FAILED	0x04
+
+/*======================================================================
+
+    Scan_header() checks to see if a memory region contains an FTL
+    partition.  build_maps() reads all the erase unit headers, builds
+    the erase unit map, and then builds the virtual page map.
+
+======================================================================*/
+
+static int scan_header(partition_t *part)
+{
+    erase_unit_header_t header;
+    loff_t offset, max_offset;
+    size_t ret;
+    int err;
+    part->header.FormattedSize = 0;
+    max_offset = (0x100000<part->mbd.mtd->size)?0x100000:part->mbd.mtd->size;
+    /* Search first megabyte for a valid FTL header */
+    for (offset = 0;
+	 (offset + sizeof(header)) < max_offset;
+	 offset += part->mbd.mtd->erasesize ? : 0x2000) {
+
+	err = mtd_read(part->mbd.mtd, offset, sizeof(header), &ret,
+                       (unsigned char *)&header);
+
+	if (err)
+	    return err;
+
+	if (strcmp(header.DataOrgTuple+3, "FTL100") == 0) break;
+    }
+
+    if (offset == max_offset) {
+	printk(KERN_NOTICE "ftl_cs: FTL header not found.\n");
+	return -ENOENT;
+    }
+    if (header.BlockSize != 9 ||
+	(header.EraseUnitSize < 10) || (header.EraseUnitSize > 31) ||
+	(header.NumTransferUnits >= le16_to_cpu(header.NumEraseUnits))) {
+	printk(KERN_NOTICE "ftl_cs: FTL header corrupt!\n");
+	return -1;
+    }
+    if ((1 << header.EraseUnitSize) != part->mbd.mtd->erasesize) {
+	printk(KERN_NOTICE "ftl: FTL EraseUnitSize %x != MTD erasesize %x\n",
+	       1 << header.EraseUnitSize,part->mbd.mtd->erasesize);
+	return -1;
+    }
+    part->header = header;
+    return 0;
+}
+
+static int build_maps(partition_t *part)
+{
+    erase_unit_header_t header;
+    uint16_t xvalid, xtrans, i;
+    unsigned blocks, j;
+    int hdr_ok, ret = -1;
+    ssize_t retval;
+    loff_t offset;
+
+    /* Set up erase unit maps */
+    part->DataUnits = le16_to_cpu(part->header.NumEraseUnits) -
+	part->header.NumTransferUnits;
+    part->EUNInfo = kmalloc_array(part->DataUnits, sizeof(struct eun_info_t),
+                                  GFP_KERNEL);
+    if (!part->EUNInfo)
+	    goto out;
+    for (i = 0; i < part->DataUnits; i++)
+	part->EUNInfo[i].Offset = 0xffffffff;
+    part->XferInfo =
+	kmalloc_array(part->header.NumTransferUnits,
+                      sizeof(struct xfer_info_t),
+                      GFP_KERNEL);
+    if (!part->XferInfo)
+	    goto out_EUNInfo;
+
+    xvalid = xtrans = 0;
+    for (i = 0; i < le16_to_cpu(part->header.NumEraseUnits); i++) {
+	offset = ((i + le16_to_cpu(part->header.FirstPhysicalEUN))
+		      << part->header.EraseUnitSize);
+	ret = mtd_read(part->mbd.mtd, offset, sizeof(header), &retval,
+                       (unsigned char *)&header);
+
+	if (ret)
+	    goto out_XferInfo;
+
+	ret = -1;
+	/* Is this a transfer partition? */
+	hdr_ok = (strcmp(header.DataOrgTuple+3, "FTL100") == 0);
+	if (hdr_ok && (le16_to_cpu(header.LogicalEUN) < part->DataUnits) &&
+	    (part->EUNInfo[le16_to_cpu(header.LogicalEUN)].Offset == 0xffffffff)) {
+	    part->EUNInfo[le16_to_cpu(header.LogicalEUN)].Offset = offset;
+	    part->EUNInfo[le16_to_cpu(header.LogicalEUN)].EraseCount =
+		le32_to_cpu(header.EraseCount);
+	    xvalid++;
+	} else {
+	    if (xtrans == part->header.NumTransferUnits) {
+		printk(KERN_NOTICE "ftl_cs: format error: too many "
+		       "transfer units!\n");
+		goto out_XferInfo;
+	    }
+	    if (hdr_ok && (le16_to_cpu(header.LogicalEUN) == 0xffff)) {
+		part->XferInfo[xtrans].state = XFER_PREPARED;
+		part->XferInfo[xtrans].EraseCount = le32_to_cpu(header.EraseCount);
+	    } else {
+		part->XferInfo[xtrans].state = XFER_UNKNOWN;
+		/* Pick anything reasonable for the erase count */
+		part->XferInfo[xtrans].EraseCount =
+		    le32_to_cpu(part->header.EraseCount);
+	    }
+	    part->XferInfo[xtrans].Offset = offset;
+	    xtrans++;
+	}
+    }
+    /* Check for format trouble */
+    header = part->header;
+    if ((xtrans != header.NumTransferUnits) ||
+	(xvalid+xtrans != le16_to_cpu(header.NumEraseUnits))) {
+	printk(KERN_NOTICE "ftl_cs: format error: erase units "
+	       "don't add up!\n");
+	goto out_XferInfo;
+    }
+
+    /* Set up virtual page map */
+    blocks = le32_to_cpu(header.FormattedSize) >> header.BlockSize;
+    part->VirtualBlockMap = vmalloc(array_size(blocks, sizeof(uint32_t)));
+    if (!part->VirtualBlockMap)
+	    goto out_XferInfo;
+
+    memset(part->VirtualBlockMap, 0xff, blocks * sizeof(uint32_t));
+    part->BlocksPerUnit = (1 << header.EraseUnitSize) >> header.BlockSize;
+
+    part->bam_cache = kmalloc_array(part->BlocksPerUnit, sizeof(uint32_t),
+                                    GFP_KERNEL);
+    if (!part->bam_cache)
+	    goto out_VirtualBlockMap;
+
+    part->bam_index = 0xffff;
+    part->FreeTotal = 0;
+
+    for (i = 0; i < part->DataUnits; i++) {
+	part->EUNInfo[i].Free = 0;
+	part->EUNInfo[i].Deleted = 0;
+	offset = part->EUNInfo[i].Offset + le32_to_cpu(header.BAMOffset);
+
+	ret = mtd_read(part->mbd.mtd, offset,
+                       part->BlocksPerUnit * sizeof(uint32_t), &retval,
+                       (unsigned char *)part->bam_cache);
+
+	if (ret)
+		goto out_bam_cache;
+
+	for (j = 0; j < part->BlocksPerUnit; j++) {
+	    if (BLOCK_FREE(le32_to_cpu(part->bam_cache[j]))) {
+		part->EUNInfo[i].Free++;
+		part->FreeTotal++;
+	    } else if ((BLOCK_TYPE(le32_to_cpu(part->bam_cache[j])) == BLOCK_DATA) &&
+		     (BLOCK_NUMBER(le32_to_cpu(part->bam_cache[j])) < blocks))
+		part->VirtualBlockMap[BLOCK_NUMBER(le32_to_cpu(part->bam_cache[j]))] =
+		    (i << header.EraseUnitSize) + (j << header.BlockSize);
+	    else if (BLOCK_DELETED(le32_to_cpu(part->bam_cache[j])))
+		part->EUNInfo[i].Deleted++;
+	}
+    }
+
+    ret = 0;
+    goto out;
+
+out_bam_cache:
+    kfree(part->bam_cache);
+out_VirtualBlockMap:
+    vfree(part->VirtualBlockMap);
+out_XferInfo:
+    kfree(part->XferInfo);
+out_EUNInfo:
+    kfree(part->EUNInfo);
+out:
+    return ret;
+} /* build_maps */
+
+/*======================================================================
+
+    Erase_xfer() schedules an asynchronous erase operation for a
+    transfer unit.
+
+======================================================================*/
+
+static int erase_xfer(partition_t *part,
+		      uint16_t xfernum)
+{
+    int ret;
+    struct xfer_info_t *xfer;
+    struct erase_info *erase;
+
+    xfer = &part->XferInfo[xfernum];
+    pr_debug("ftl_cs: erasing xfer unit at 0x%x\n", xfer->Offset);
+    xfer->state = XFER_ERASING;
+
+    /* Is there a free erase slot? Always in MTD. */
+
+
+    erase=kmalloc(sizeof(struct erase_info), GFP_KERNEL);
+    if (!erase)
+            return -ENOMEM;
+
+    erase->addr = xfer->Offset;
+    erase->len = 1 << part->header.EraseUnitSize;
+
+    ret = mtd_erase(part->mbd.mtd, erase);
+    if (!ret) {
+	xfer->state = XFER_ERASED;
+	xfer->EraseCount++;
+    } else {
+	xfer->state = XFER_FAILED;
+	pr_notice("ftl_cs: erase failed: err = %d\n", ret);
+    }
+
+    kfree(erase);
+
+    return ret;
+} /* erase_xfer */
+
+/*======================================================================
+
+    Prepare_xfer() takes a freshly erased transfer unit and gives
+    it an appropriate header.
+
+======================================================================*/
+
+static int prepare_xfer(partition_t *part, int i)
+{
+    erase_unit_header_t header;
+    struct xfer_info_t *xfer;
+    int nbam, ret;
+    uint32_t ctl;
+    ssize_t retlen;
+    loff_t offset;
+
+    xfer = &part->XferInfo[i];
+    xfer->state = XFER_FAILED;
+
+    pr_debug("ftl_cs: preparing xfer unit at 0x%x\n", xfer->Offset);
+
+    /* Write the transfer unit header */
+    header = part->header;
+    header.LogicalEUN = cpu_to_le16(0xffff);
+    header.EraseCount = cpu_to_le32(xfer->EraseCount);
+
+    ret = mtd_write(part->mbd.mtd, xfer->Offset, sizeof(header), &retlen,
+                    (u_char *)&header);
+
+    if (ret) {
+	return ret;
+    }
+
+    /* Write the BAM stub */
+    nbam = DIV_ROUND_UP(part->BlocksPerUnit * sizeof(uint32_t) +
+			le32_to_cpu(part->header.BAMOffset), SECTOR_SIZE);
+
+    offset = xfer->Offset + le32_to_cpu(part->header.BAMOffset);
+    ctl = cpu_to_le32(BLOCK_CONTROL);
+
+    for (i = 0; i < nbam; i++, offset += sizeof(uint32_t)) {
+
+	ret = mtd_write(part->mbd.mtd, offset, sizeof(uint32_t), &retlen,
+                        (u_char *)&ctl);
+
+	if (ret)
+	    return ret;
+    }
+    xfer->state = XFER_PREPARED;
+    return 0;
+
+} /* prepare_xfer */
+
+/*======================================================================
+
+    Copy_erase_unit() takes a full erase block and a transfer unit,
+    copies everything to the transfer unit, then swaps the block
+    pointers.
+
+    All data blocks are copied to the corresponding blocks in the
+    target unit, so the virtual block map does not need to be
+    updated.
+
+======================================================================*/
+
+static int copy_erase_unit(partition_t *part, uint16_t srcunit,
+			   uint16_t xferunit)
+{
+    u_char buf[SECTOR_SIZE];
+    struct eun_info_t *eun;
+    struct xfer_info_t *xfer;
+    uint32_t src, dest, free, i;
+    uint16_t unit;
+    int ret;
+    ssize_t retlen;
+    loff_t offset;
+    uint16_t srcunitswap = cpu_to_le16(srcunit);
+
+    eun = &part->EUNInfo[srcunit];
+    xfer = &part->XferInfo[xferunit];
+    pr_debug("ftl_cs: copying block 0x%x to 0x%x\n",
+	  eun->Offset, xfer->Offset);
+
+
+    /* Read current BAM */
+    if (part->bam_index != srcunit) {
+
+	offset = eun->Offset + le32_to_cpu(part->header.BAMOffset);
+
+	ret = mtd_read(part->mbd.mtd, offset,
+                       part->BlocksPerUnit * sizeof(uint32_t), &retlen,
+                       (u_char *)(part->bam_cache));
+
+	/* mark the cache bad, in case we get an error later */
+	part->bam_index = 0xffff;
+
+	if (ret) {
+	    printk( KERN_WARNING "ftl: Failed to read BAM cache in copy_erase_unit()!\n");
+	    return ret;
+	}
+    }
+
+    /* Write the LogicalEUN for the transfer unit */
+    xfer->state = XFER_UNKNOWN;
+    offset = xfer->Offset + 20; /* Bad! */
+    unit = cpu_to_le16(0x7fff);
+
+    ret = mtd_write(part->mbd.mtd, offset, sizeof(uint16_t), &retlen,
+                    (u_char *)&unit);
+
+    if (ret) {
+	printk( KERN_WARNING "ftl: Failed to write back to BAM cache in copy_erase_unit()!\n");
+	return ret;
+    }
+
+    /* Copy all data blocks from source unit to transfer unit */
+    src = eun->Offset; dest = xfer->Offset;
+
+    free = 0;
+    ret = 0;
+    for (i = 0; i < part->BlocksPerUnit; i++) {
+	switch (BLOCK_TYPE(le32_to_cpu(part->bam_cache[i]))) {
+	case BLOCK_CONTROL:
+	    /* This gets updated later */
+	    break;
+	case BLOCK_DATA:
+	case BLOCK_REPLACEMENT:
+	    ret = mtd_read(part->mbd.mtd, src, SECTOR_SIZE, &retlen,
+                           (u_char *)buf);
+	    if (ret) {
+		printk(KERN_WARNING "ftl: Error reading old xfer unit in copy_erase_unit\n");
+		return ret;
+            }
+
+
+	    ret = mtd_write(part->mbd.mtd, dest, SECTOR_SIZE, &retlen,
+                            (u_char *)buf);
+	    if (ret)  {
+		printk(KERN_WARNING "ftl: Error writing new xfer unit in copy_erase_unit\n");
+		return ret;
+            }
+
+	    break;
+	default:
+	    /* All other blocks must be free */
+	    part->bam_cache[i] = cpu_to_le32(0xffffffff);
+	    free++;
+	    break;
+	}
+	src += SECTOR_SIZE;
+	dest += SECTOR_SIZE;
+    }
+
+    /* Write the BAM to the transfer unit */
+    ret = mtd_write(part->mbd.mtd,
+                    xfer->Offset + le32_to_cpu(part->header.BAMOffset),
+                    part->BlocksPerUnit * sizeof(int32_t),
+                    &retlen,
+                    (u_char *)part->bam_cache);
+    if (ret) {
+	printk( KERN_WARNING "ftl: Error writing BAM in copy_erase_unit\n");
+	return ret;
+    }
+
+
+    /* All clear? Then update the LogicalEUN again */
+    ret = mtd_write(part->mbd.mtd, xfer->Offset + 20, sizeof(uint16_t),
+                    &retlen, (u_char *)&srcunitswap);
+
+    if (ret) {
+	printk(KERN_WARNING "ftl: Error writing new LogicalEUN in copy_erase_unit\n");
+	return ret;
+    }
+
+
+    /* Update the maps and usage stats*/
+    swap(xfer->EraseCount, eun->EraseCount);
+    swap(xfer->Offset, eun->Offset);
+    part->FreeTotal -= eun->Free;
+    part->FreeTotal += free;
+    eun->Free = free;
+    eun->Deleted = 0;
+
+    /* Now, the cache should be valid for the new block */
+    part->bam_index = srcunit;
+
+    return 0;
+} /* copy_erase_unit */
+
+/*======================================================================
+
+    reclaim_block() picks a full erase unit and a transfer unit and
+    then calls copy_erase_unit() to copy one to the other.  Then, it
+    schedules an erase on the expired block.
+
+    What's a good way to decide which transfer unit and which erase
+    unit to use?  Beats me.  My way is to always pick the transfer
+    unit with the fewest erases, and usually pick the data unit with
+    the most deleted blocks.  But with a small probability, pick the
+    oldest data unit instead.  This means that we generally postpone
+    the next reclamation as long as possible, but shuffle static
+    stuff around a bit for wear leveling.
+
+======================================================================*/
+
+static int reclaim_block(partition_t *part)
+{
+    uint16_t i, eun, xfer;
+    uint32_t best;
+    int queued, ret;
+
+    pr_debug("ftl_cs: reclaiming space...\n");
+    pr_debug("NumTransferUnits == %x\n", part->header.NumTransferUnits);
+    /* Pick the least erased transfer unit */
+    best = 0xffffffff; xfer = 0xffff;
+    do {
+	queued = 0;
+	for (i = 0; i < part->header.NumTransferUnits; i++) {
+	    int n=0;
+	    if (part->XferInfo[i].state == XFER_UNKNOWN) {
+		pr_debug("XferInfo[%d].state == XFER_UNKNOWN\n",i);
+		n=1;
+		erase_xfer(part, i);
+	    }
+	    if (part->XferInfo[i].state == XFER_ERASING) {
+		pr_debug("XferInfo[%d].state == XFER_ERASING\n",i);
+		n=1;
+		queued = 1;
+	    }
+	    else if (part->XferInfo[i].state == XFER_ERASED) {
+		pr_debug("XferInfo[%d].state == XFER_ERASED\n",i);
+		n=1;
+		prepare_xfer(part, i);
+	    }
+	    if (part->XferInfo[i].state == XFER_PREPARED) {
+		pr_debug("XferInfo[%d].state == XFER_PREPARED\n",i);
+		n=1;
+		if (part->XferInfo[i].EraseCount <= best) {
+		    best = part->XferInfo[i].EraseCount;
+		    xfer = i;
+		}
+	    }
+		if (!n)
+		    pr_debug("XferInfo[%d].state == %x\n",i, part->XferInfo[i].state);
+
+	}
+	if (xfer == 0xffff) {
+	    if (queued) {
+		pr_debug("ftl_cs: waiting for transfer "
+		      "unit to be prepared...\n");
+		mtd_sync(part->mbd.mtd);
+	    } else {
+		static int ne = 0;
+		if (++ne < 5)
+		    printk(KERN_NOTICE "ftl_cs: reclaim failed: no "
+			   "suitable transfer units!\n");
+		else
+		    pr_debug("ftl_cs: reclaim failed: no "
+			  "suitable transfer units!\n");
+
+		return -EIO;
+	    }
+	}
+    } while (xfer == 0xffff);
+
+    eun = 0;
+    if ((jiffies % shuffle_freq) == 0) {
+	pr_debug("ftl_cs: recycling freshest block...\n");
+	best = 0xffffffff;
+	for (i = 0; i < part->DataUnits; i++)
+	    if (part->EUNInfo[i].EraseCount <= best) {
+		best = part->EUNInfo[i].EraseCount;
+		eun = i;
+	    }
+    } else {
+	best = 0;
+	for (i = 0; i < part->DataUnits; i++)
+	    if (part->EUNInfo[i].Deleted >= best) {
+		best = part->EUNInfo[i].Deleted;
+		eun = i;
+	    }
+	if (best == 0) {
+	    static int ne = 0;
+	    if (++ne < 5)
+		printk(KERN_NOTICE "ftl_cs: reclaim failed: "
+		       "no free blocks!\n");
+	    else
+		pr_debug("ftl_cs: reclaim failed: "
+		       "no free blocks!\n");
+
+	    return -EIO;
+	}
+    }
+    ret = copy_erase_unit(part, eun, xfer);
+    if (!ret)
+	erase_xfer(part, xfer);
+    else
+	printk(KERN_NOTICE "ftl_cs: copy_erase_unit failed!\n");
+    return ret;
+} /* reclaim_block */
+
+/*======================================================================
+
+    Find_free() searches for a free block.  If necessary, it updates
+    the BAM cache for the erase unit containing the free block.  It
+    returns the block index -- the erase unit is just the currently
+    cached unit.  If there are no free blocks, it returns 0 -- this
+    is never a valid data block because it contains the header.
+
+======================================================================*/
+
+#ifdef PSYCHO_DEBUG
+static void dump_lists(partition_t *part)
+{
+    int i;
+    printk(KERN_DEBUG "ftl_cs: Free total = %d\n", part->FreeTotal);
+    for (i = 0; i < part->DataUnits; i++)
+	printk(KERN_DEBUG "ftl_cs:   unit %d: %d phys, %d free, "
+	       "%d deleted\n", i,
+	       part->EUNInfo[i].Offset >> part->header.EraseUnitSize,
+	       part->EUNInfo[i].Free, part->EUNInfo[i].Deleted);
+}
+#endif
+
+static uint32_t find_free(partition_t *part)
+{
+    uint16_t stop, eun;
+    uint32_t blk;
+    size_t retlen;
+    int ret;
+
+    /* Find an erase unit with some free space */
+    stop = (part->bam_index == 0xffff) ? 0 : part->bam_index;
+    eun = stop;
+    do {
+	if (part->EUNInfo[eun].Free != 0) break;
+	/* Wrap around at end of table */
+	if (++eun == part->DataUnits) eun = 0;
+    } while (eun != stop);
+
+    if (part->EUNInfo[eun].Free == 0)
+	return 0;
+
+    /* Is this unit's BAM cached? */
+    if (eun != part->bam_index) {
+	/* Invalidate cache */
+	part->bam_index = 0xffff;
+
+	ret = mtd_read(part->mbd.mtd,
+                       part->EUNInfo[eun].Offset + le32_to_cpu(part->header.BAMOffset),
+                       part->BlocksPerUnit * sizeof(uint32_t),
+                       &retlen,
+                       (u_char *)(part->bam_cache));
+
+	if (ret) {
+	    printk(KERN_WARNING"ftl: Error reading BAM in find_free\n");
+	    return 0;
+	}
+	part->bam_index = eun;
+    }
+
+    /* Find a free block */
+    for (blk = 0; blk < part->BlocksPerUnit; blk++)
+	if (BLOCK_FREE(le32_to_cpu(part->bam_cache[blk]))) break;
+    if (blk == part->BlocksPerUnit) {
+#ifdef PSYCHO_DEBUG
+	static int ne = 0;
+	if (++ne == 1)
+	    dump_lists(part);
+#endif
+	printk(KERN_NOTICE "ftl_cs: bad free list!\n");
+	return 0;
+    }
+    pr_debug("ftl_cs: found free block at %d in %d\n", blk, eun);
+    return blk;
+
+} /* find_free */
+
+
+/*======================================================================
+
+    Read a series of sectors from an FTL partition.
+
+======================================================================*/
+
+static int ftl_read(partition_t *part, caddr_t buffer,
+		    u_long sector, u_long nblocks)
+{
+    uint32_t log_addr, bsize;
+    u_long i;
+    int ret;
+    size_t offset, retlen;
+
+    pr_debug("ftl_cs: ftl_read(0x%p, 0x%lx, %ld)\n",
+	  part, sector, nblocks);
+    if (!(part->state & FTL_FORMATTED)) {
+	printk(KERN_NOTICE "ftl_cs: bad partition\n");
+	return -EIO;
+    }
+    bsize = 1 << part->header.EraseUnitSize;
+
+    for (i = 0; i < nblocks; i++) {
+	if (((sector+i) * SECTOR_SIZE) >= le32_to_cpu(part->header.FormattedSize)) {
+	    printk(KERN_NOTICE "ftl_cs: bad read offset\n");
+	    return -EIO;
+	}
+	log_addr = part->VirtualBlockMap[sector+i];
+	if (log_addr == 0xffffffff)
+	    memset(buffer, 0, SECTOR_SIZE);
+	else {
+	    offset = (part->EUNInfo[log_addr / bsize].Offset
+			  + (log_addr % bsize));
+	    ret = mtd_read(part->mbd.mtd, offset, SECTOR_SIZE, &retlen,
+                           (u_char *)buffer);
+
+	    if (ret) {
+		printk(KERN_WARNING "Error reading MTD device in ftl_read()\n");
+		return ret;
+	    }
+	}
+	buffer += SECTOR_SIZE;
+    }
+    return 0;
+} /* ftl_read */
+
+/*======================================================================
+
+    Write a series of sectors to an FTL partition
+
+======================================================================*/
+
+static int set_bam_entry(partition_t *part, uint32_t log_addr,
+			 uint32_t virt_addr)
+{
+    uint32_t bsize, blk, le_virt_addr;
+#ifdef PSYCHO_DEBUG
+    uint32_t old_addr;
+#endif
+    uint16_t eun;
+    int ret;
+    size_t retlen, offset;
+
+    pr_debug("ftl_cs: set_bam_entry(0x%p, 0x%x, 0x%x)\n",
+	  part, log_addr, virt_addr);
+    bsize = 1 << part->header.EraseUnitSize;
+    eun = log_addr / bsize;
+    blk = (log_addr % bsize) / SECTOR_SIZE;
+    offset = (part->EUNInfo[eun].Offset + blk * sizeof(uint32_t) +
+		  le32_to_cpu(part->header.BAMOffset));
+
+#ifdef PSYCHO_DEBUG
+    ret = mtd_read(part->mbd.mtd, offset, sizeof(uint32_t), &retlen,
+                   (u_char *)&old_addr);
+    if (ret) {
+	printk(KERN_WARNING"ftl: Error reading old_addr in set_bam_entry: %d\n",ret);
+	return ret;
+    }
+    old_addr = le32_to_cpu(old_addr);
+
+    if (((virt_addr == 0xfffffffe) && !BLOCK_FREE(old_addr)) ||
+	((virt_addr == 0) && (BLOCK_TYPE(old_addr) != BLOCK_DATA)) ||
+	(!BLOCK_DELETED(virt_addr) && (old_addr != 0xfffffffe))) {
+	static int ne = 0;
+	if (++ne < 5) {
+	    printk(KERN_NOTICE "ftl_cs: set_bam_entry() inconsistency!\n");
+	    printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, old = 0x%x"
+		   ", new = 0x%x\n", log_addr, old_addr, virt_addr);
+	}
+	return -EIO;
+    }
+#endif
+    le_virt_addr = cpu_to_le32(virt_addr);
+    if (part->bam_index == eun) {
+#ifdef PSYCHO_DEBUG
+	if (le32_to_cpu(part->bam_cache[blk]) != old_addr) {
+	    static int ne = 0;
+	    if (++ne < 5) {
+		printk(KERN_NOTICE "ftl_cs: set_bam_entry() "
+		       "inconsistency!\n");
+		printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, cache"
+		       " = 0x%x\n",
+		       le32_to_cpu(part->bam_cache[blk]), old_addr);
+	    }
+	    return -EIO;
+	}
+#endif
+	part->bam_cache[blk] = le_virt_addr;
+    }
+    ret = mtd_write(part->mbd.mtd, offset, sizeof(uint32_t), &retlen,
+                    (u_char *)&le_virt_addr);
+
+    if (ret) {
+	printk(KERN_NOTICE "ftl_cs: set_bam_entry() failed!\n");
+	printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, new = 0x%x\n",
+	       log_addr, virt_addr);
+    }
+    return ret;
+} /* set_bam_entry */
+
+static int ftl_write(partition_t *part, caddr_t buffer,
+		     u_long sector, u_long nblocks)
+{
+    uint32_t bsize, log_addr, virt_addr, old_addr, blk;
+    u_long i;
+    int ret;
+    size_t retlen, offset;
+
+    pr_debug("ftl_cs: ftl_write(0x%p, %ld, %ld)\n",
+	  part, sector, nblocks);
+    if (!(part->state & FTL_FORMATTED)) {
+	printk(KERN_NOTICE "ftl_cs: bad partition\n");
+	return -EIO;
+    }
+    /* See if we need to reclaim space, before we start */
+    while (part->FreeTotal < nblocks) {
+	ret = reclaim_block(part);
+	if (ret)
+	    return ret;
+    }
+
+    bsize = 1 << part->header.EraseUnitSize;
+
+    virt_addr = sector * SECTOR_SIZE | BLOCK_DATA;
+    for (i = 0; i < nblocks; i++) {
+	if (virt_addr >= le32_to_cpu(part->header.FormattedSize)) {
+	    printk(KERN_NOTICE "ftl_cs: bad write offset\n");
+	    return -EIO;
+	}
+
+	/* Grab a free block */
+	blk = find_free(part);
+	if (blk == 0) {
+	    static int ne = 0;
+	    if (++ne < 5)
+		printk(KERN_NOTICE "ftl_cs: internal error: "
+		       "no free blocks!\n");
+	    return -ENOSPC;
+	}
+
+	/* Tag the BAM entry, and write the new block */
+	log_addr = part->bam_index * bsize + blk * SECTOR_SIZE;
+	part->EUNInfo[part->bam_index].Free--;
+	part->FreeTotal--;
+	if (set_bam_entry(part, log_addr, 0xfffffffe))
+	    return -EIO;
+	part->EUNInfo[part->bam_index].Deleted++;
+	offset = (part->EUNInfo[part->bam_index].Offset +
+		      blk * SECTOR_SIZE);
+	ret = mtd_write(part->mbd.mtd, offset, SECTOR_SIZE, &retlen, buffer);
+
+	if (ret) {
+	    printk(KERN_NOTICE "ftl_cs: block write failed!\n");
+	    printk(KERN_NOTICE "ftl_cs:   log_addr = 0x%x, virt_addr"
+		   " = 0x%x, Offset = 0x%zx\n", log_addr, virt_addr,
+		   offset);
+	    return -EIO;
+	}
+
+	/* Only delete the old entry when the new entry is ready */
+	old_addr = part->VirtualBlockMap[sector+i];
+	if (old_addr != 0xffffffff) {
+	    part->VirtualBlockMap[sector+i] = 0xffffffff;
+	    part->EUNInfo[old_addr/bsize].Deleted++;
+	    if (set_bam_entry(part, old_addr, 0))
+		return -EIO;
+	}
+
+	/* Finally, set up the new pointers */
+	if (set_bam_entry(part, log_addr, virt_addr))
+	    return -EIO;
+	part->VirtualBlockMap[sector+i] = log_addr;
+	part->EUNInfo[part->bam_index].Deleted--;
+
+	buffer += SECTOR_SIZE;
+	virt_addr += SECTOR_SIZE;
+    }
+    return 0;
+} /* ftl_write */
+
+static int ftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
+{
+	partition_t *part = (void *)dev;
+	u_long sect;
+
+	/* Sort of arbitrary: round size down to 4KiB boundary */
+	sect = le32_to_cpu(part->header.FormattedSize)/SECTOR_SIZE;
+
+	geo->heads = 1;
+	geo->sectors = 8;
+	geo->cylinders = sect >> 3;
+
+	return 0;
+}
+
+static int ftl_readsect(struct mtd_blktrans_dev *dev,
+			      unsigned long block, char *buf)
+{
+	return ftl_read((void *)dev, buf, block, 1);
+}
+
+static int ftl_writesect(struct mtd_blktrans_dev *dev,
+			      unsigned long block, char *buf)
+{
+	return ftl_write((void *)dev, buf, block, 1);
+}
+
+static int ftl_discardsect(struct mtd_blktrans_dev *dev,
+			   unsigned long sector, unsigned nr_sects)
+{
+	partition_t *part = (void *)dev;
+	uint32_t bsize = 1 << part->header.EraseUnitSize;
+
+	pr_debug("FTL erase sector %ld for %d sectors\n",
+	      sector, nr_sects);
+
+	while (nr_sects) {
+		uint32_t old_addr = part->VirtualBlockMap[sector];
+		if (old_addr != 0xffffffff) {
+			part->VirtualBlockMap[sector] = 0xffffffff;
+			part->EUNInfo[old_addr/bsize].Deleted++;
+			if (set_bam_entry(part, old_addr, 0))
+				return -EIO;
+		}
+		nr_sects--;
+		sector++;
+	}
+
+	return 0;
+}
+/*====================================================================*/
+
+static void ftl_freepart(partition_t *part)
+{
+	vfree(part->VirtualBlockMap);
+	part->VirtualBlockMap = NULL;
+	kfree(part->EUNInfo);
+	part->EUNInfo = NULL;
+	kfree(part->XferInfo);
+	part->XferInfo = NULL;
+	kfree(part->bam_cache);
+	part->bam_cache = NULL;
+} /* ftl_freepart */
+
+static void ftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
+{
+	partition_t *partition;
+
+	partition = kzalloc(sizeof(partition_t), GFP_KERNEL);
+
+	if (!partition) {
+		printk(KERN_WARNING "No memory to scan for FTL on %s\n",
+		       mtd->name);
+		return;
+	}
+
+	partition->mbd.mtd = mtd;
+
+	if ((scan_header(partition) == 0) &&
+	    (build_maps(partition) == 0)) {
+
+		partition->state = FTL_FORMATTED;
+#ifdef PCMCIA_DEBUG
+		printk(KERN_INFO "ftl_cs: opening %d KiB FTL partition\n",
+		       le32_to_cpu(partition->header.FormattedSize) >> 10);
+#endif
+		partition->mbd.size = le32_to_cpu(partition->header.FormattedSize) >> 9;
+
+		partition->mbd.tr = tr;
+		partition->mbd.devnum = -1;
+		if (!add_mtd_blktrans_dev((void *)partition))
+			return;
+	}
+
+	kfree(partition);
+}
+
+static void ftl_remove_dev(struct mtd_blktrans_dev *dev)
+{
+	del_mtd_blktrans_dev(dev);
+	ftl_freepart((partition_t *)dev);
+}
+
+static struct mtd_blktrans_ops ftl_tr = {
+	.name		= "ftl",
+	.major		= FTL_MAJOR,
+	.part_bits	= PART_BITS,
+	.blksize 	= SECTOR_SIZE,
+	.readsect	= ftl_readsect,
+	.writesect	= ftl_writesect,
+	.discard	= ftl_discardsect,
+	.getgeo		= ftl_getgeo,
+	.add_mtd	= ftl_add_mtd,
+	.remove_dev	= ftl_remove_dev,
+	.owner		= THIS_MODULE,
+};
+
+static int __init init_ftl(void)
+{
+	return register_mtd_blktrans(&ftl_tr);
+}
+
+static void __exit cleanup_ftl(void)
+{
+	deregister_mtd_blktrans(&ftl_tr);
+}
+
+module_init(init_ftl);
+module_exit(cleanup_ftl);
+
+
+MODULE_LICENSE("Dual MPL/GPL");
+MODULE_AUTHOR("David Hinds <dahinds@users.sourceforge.net>");
+MODULE_DESCRIPTION("Support code for Flash Translation Layer, used on PCMCIA devices");