ftl.c

基于linux-2.6.28的mtd驱动

/* This version ported to the Linux-MTD system by [e-mail]
 *
 * Fixes: Arnaldo Carvalho de Melo <[e-mail]>
 * - 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
    <[e-mail]>.  Portions created by David A. Hinds
    are Copyright (C) 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 (http://www.m-sys.com) directly.

======================================================================*/
#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 <asm/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;
    u_int32_t		state;
    u_int32_t		*VirtualBlockMap;
    u_int32_t		*VirtualPageMap;
    u_int32_t		FreeTotal;
    struct eun_info_t {
	u_int32_t		Offset;
	u_int32_t		EraseCount;
	u_int32_t		Free;
	u_int32_t		Deleted;
    } *EUNInfo;
    struct xfer_info_t {
	u_int32_t		Offset;
	u_int32_t		EraseCount;
	u_int16_t		state;
    } *XferInfo;
    u_int16_t		bam_index;
    u_int32_t		*bam_cache;
    u_int16_t		DataUnits;
    u_int32_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

/*====================================================================*/


static void ftl_erase_callback(struct erase_info *done);


/*======================================================================

    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 = part->mbd.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;
    u_int16_t xvalid, xtrans, i;
    u_int 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(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(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 = part->mbd.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(blocks * sizeof(u_int32_t));
    if (!part->VirtualBlockMap)
	    goto out_XferInfo;

    memset(part->VirtualBlockMap, 0xff, blocks * sizeof(u_int32_t));
    part->BlocksPerUnit = (1 << header.EraseUnitSize) >> header.BlockSize;

    part->bam_cache = kmalloc(part->BlocksPerUnit * sizeof(u_int32_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 = part->mbd.mtd->read(part->mbd.mtd, offset,
			      part->BlocksPerUnit * sizeof(u_int32_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,
		      u_int16_t xfernum)
{
    int ret;
    struct xfer_info_t *xfer;
    struct erase_info *erase;

    xfer = &part->XferInfo[xfernum];
    DEBUG(1, "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->mtd = part->mbd.mtd;
    erase->callback = ftl_erase_callback;
    erase->addr = xfer->Offset;
    erase->len = 1 << part->header.EraseUnitSize;
    erase->priv = (u_long)part;

    ret = part->mbd.mtd->erase(part->mbd.mtd, erase);

    if (!ret)
	    xfer->EraseCount++;
    else
	    kfree(erase);

    return ret;
} /* erase_xfer */

/*======================================================================

    Prepare_xfer() takes a freshly erased transfer unit and gives
    it an appropriate header.

======================================================================*/