From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from nf-out-0910.google.com ([64.233.182.188]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1J2iYO-0006Ig-In for linux-mtd@lists.infradead.org; Thu, 13 Dec 2007 07:32:27 +0000 Received: by nf-out-0910.google.com with SMTP id h3so426243nfh.22 for ; Wed, 12 Dec 2007 23:32:18 -0800 (PST) Message-ID: <4760E013.3050408@gmail.com> Date: Thu, 13 Dec 2007 08:32:35 +0100 MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: [PATCH] [MTD] ROMBLOCK: Readonly Block Device Layer Over MTD Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit From: Gregory CLEMENT Cc: =?ISO-8859-1?Q?Engel?= , Vitaly Wool , Konstantin Baydarov , =?ISO-8859-1?Q?J=F6rn_?= List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, I generated this patch for linux 2.6.24.rc5 and tested it with cramfs and squashfs file systems. As Konstantin Baydarov submit this patch first maybe it would be better than he sign this patch, but if he can't or don't want it, I don't mind sign it... From: Gregory CLEMENT Date: Wed, 12 Dec 2007 17:41:23 +0100 Subject: [PATCH] [MTD] ROMBLOCK: Readonly Block Device Layer Over MTD Description: The following patch adds readonly block device layer over mtd that allows to use any filesystem on this device in RO mode and thus gain faster mount times and better throughput rates. It allows to put one RO filesystem into NAND using a bad-block aware program initially, and mount it. But be aware, it doesn't handle run- time bit flips or errors (even if this event seems pretty rare). How it works: Blocks translation routine was added to read sector function. Assuming that bad block won't appear during MTD reading and BBT is correct, bad block is skipped and requested block is lazily mapped to good one. Block driver based on the mtd readonly device driver mtdblock_ro.c and translation routine was taken from the patch of Pantelis Antoniou (which can be found at http://lists.infradead.org/pipermail/linux-mtd/2004-May/009672.html). This patch was originally submit by Konstantin Baydarov, but never included nor rejected ( see http://lists.infradead.org/pipermail/linux-mtd/2006-November/016835.html). Signed-off-by: Gregory CLEMENT --- drivers/mtd/Kconfig | 7 ++ drivers/mtd/Makefile | 1 + drivers/mtd/romblock.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 181 insertions(+), 0 deletions(-) create mode 100644 drivers/mtd/romblock.c diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig index 8848e8a..dd6ae3a 100644 --- a/drivers/mtd/Kconfig +++ b/drivers/mtd/Kconfig @@ -200,6 +200,13 @@ config MTD_BLOCK_RO You do not need this option for use with the DiskOnChip devices. For those, enable NFTL support (CONFIG_NFTL) instead. +config MTD_BLOCK_ROMBLOCK + tristate "Readonly Block Device Layer Over MTD" + depends on MTD + help + Same as readonly block driver, but this allow you to mount read-only file + systems from an MTD device, containing bad blocks. + config FTL tristate "FTL (Flash Translation Layer) support" depends on BLOCK diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile index 7f0b04b..9cb4683 100644 --- a/drivers/mtd/Makefile +++ b/drivers/mtd/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_MTD_CHAR) += mtdchar.o obj-$(CONFIG_MTD_BLKDEVS) += mtd_blkdevs.o obj-$(CONFIG_MTD_BLOCK) += mtdblock.o obj-$(CONFIG_MTD_BLOCK_RO) += mtdblock_ro.o +obj-$(CONFIG_MTD_BLOCK_ROMBLOCK) += romblock.o mtd_blkdevs.o obj-$(CONFIG_FTL) += ftl.o obj-$(CONFIG_NFTL) += nftl.o obj-$(CONFIG_INFTL) += inftl.o diff --git a/drivers/mtd/romblock.c b/drivers/mtd/romblock.c new file mode 100644 index 0000000..b02efae --- /dev/null +++ b/drivers/mtd/romblock.c @@ -0,0 +1,173 @@ +/* + * Readonly Block Device Layer Over MTD + * + * (C) 2006 Baydarov Konstantin + * Pantelis Antoniou + * David Woodhouse + * + * It allows to use any filesystem on this device in + * RO mode and thus gain faster mount times and better + * throughput rates. + * It allows to put one RO filesystem into NAND using a + * bad-block aware program initially, and mount it. But be aware, + * it doesn't handle run-time bit flips or errors (even if this event + * seems pretty rare). + * + */ + +#include +#include +#include +#include + +struct romblock_map { + struct mtd_blktrans_dev dev; + /* block map for RO */ + int32_t *block_map; + int32_t block_top; + int32_t block_scantop; +}; + +static loff_t map_over_bad_blocks(struct mtd_blktrans_dev *dev, loff_t from) +{ + int i, block; + struct mtd_info *mtd = dev->mtd; + struct romblock_map *dev_cont = + container_of(dev, struct romblock_map, dev); + int32_t *block_map = dev_cont->block_map; + int32_t block_top = dev_cont->block_top; + int32_t block_scantop = dev_cont->block_scantop; + + /* if no bad block checking is possible bail out */ + if (mtd->block_isbad == NULL) + return from; + + /* first time in */ + if (block_map == NULL) { + block_top = mtd->size / mtd->erasesize; + + block_map = kmalloc(sizeof(*block_map) * block_top, GFP_KERNEL); + if (block_map == NULL) { + printk(KERN_ERR + "map_over_bad_blocks(): unable to allocate block map\n"); + return -ENOMEM; + } + for (i = 0; i < block_top; i++) + block_map[i] = -1; + + for (i = 0; i < block_top; i++) + if ((*mtd->block_isbad) (mtd, i * mtd->erasesize) == 0) + break; + + if (i >= block_top) { + printk(KERN_WARNING + "map_over_bad_blocks(): all blocks bad!\n"); + return -EIO; + } + block_scantop = 0; + block_map[0] = i; + + DEBUG(MTD_DEBUG_LEVEL0, "mtd: map %d -> %d\n", block_scantop, + block_map[block_scantop]); + } + + block = ((int)from / mtd->erasesize); + if (block >= block_top) + return (loff_t)-1; + + /* scan for bad block up to where we want */ + while (block >= block_scantop) { + /* find a non bad block */ + for (i = block_map[block_scantop] + 1; i < block_top; i++) + if ((*mtd->block_isbad) (mtd, i * mtd->erasesize) == 0) + break; + + /* exhausted ? */ + if (i >= block_top) { + printk(KERN_WARNING + "map_over_bad_blocks(): no more good blocks!\n"); + return (loff_t)-1; + } + + block_map[++block_scantop] = i; + DEBUG(MTD_DEBUG_LEVEL0, "mtd: map %d -> %d\n", block_scantop, + block_map[block_scantop]); + } + + block = block_map[(int)from / mtd->erasesize]; + from = (block * mtd->erasesize) | ((int)from & (mtd->erasesize - 1)); + return from; +} + +static int romblock_readsect(struct mtd_blktrans_dev *dev, + unsigned long block, char *buf) +{ + size_t retlen; + unsigned long from; + from = map_over_bad_blocks(dev, block << 9); + + if (dev->mtd->read(dev->mtd, from, 512, &retlen, buf)) + return 1; + return 0; +} + +static int romblock_writesect(struct mtd_blktrans_dev *dev, + unsigned long block, char *buf) +{ + size_t retlen; + + if (dev->mtd->write(dev->mtd, (block * 512), 512, &retlen, buf)) + return 1; + return 0; +} + +static void romblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) +{ + struct romblock_map *dev_cont = kzalloc(sizeof(*dev_cont), GFP_KERNEL); + + if (!dev_cont) + return; + + dev_cont->dev.mtd = mtd; + dev_cont->dev.devnum = mtd->index; + dev_cont->dev.size = mtd->size >> 9; + dev_cont->dev.tr = tr; + dev_cont->dev.readonly = 1; + + add_mtd_blktrans_dev(&(dev_cont->dev)); +} + +static void romblock_remove_dev(struct mtd_blktrans_dev *dev) +{ + del_mtd_blktrans_dev(dev); + kfree(dev); +} + +static struct mtd_blktrans_ops romblock_tr = { + .name = "romblock", + .major = 240, /*experimental number as 258 seems not to working */ + .part_bits = 0, + .blksize = 512, + .readsect = romblock_readsect, + .writesect = romblock_writesect, + .add_mtd = romblock_add_mtd, + .remove_dev = romblock_remove_dev, + .owner = THIS_MODULE, +}; + +static int __init romblock_init(void) +{ + return register_mtd_blktrans(&romblock_tr); +} + +static void __exit romblock_exit(void) +{ + deregister_mtd_blktrans(&romblock_tr); +} + +module_init(romblock_init); +module_exit(romblock_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Baydarov Konstantin "); +MODULE_DESCRIPTION("Readonly Block Device Layer Over MTD"); -- 1.5.3.7 -- Gregory CLEMENT Adeneo Adetel Group 2, chemin du Ruisseau 69134 ECULLY - FRANCE Tél. : +33 (0)4 72 18 08 40 - Fax : +33 (0)4 72 18 08 41 www.adetelgroup.com