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    Subject[PATCH 14/17] MTD: common module for smartmedia/xD support
    Date
    This small module implements few helpers that are usefull
    for nand drivers for SmartMedia/xD card readers.

    Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
    ---
    drivers/mtd/nand/Kconfig | 9 +++
    drivers/mtd/nand/Makefile | 1 +
    drivers/mtd/nand/sm_common.c | 114 ++++++++++++++++++++++++++++++++++++++++++
    drivers/mtd/nand/sm_common.h | 61 ++++++++++++++++++++++
    4 files changed, 185 insertions(+), 0 deletions(-)
    create mode 100644 drivers/mtd/nand/sm_common.c
    create mode 100644 drivers/mtd/nand/sm_common.h
    diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
    index 677cd53..13c1fb2 100644
    --- a/drivers/mtd/nand/Kconfig
    +++ b/drivers/mtd/nand/Kconfig
    @@ -18,6 +18,10 @@ config MTD_NAND_VERIFY_WRITE
    device thinks the write was successful, a bit could have been
    flipped accidentally due to device wear or something else.

    +config MTD_NAND_SMARTMEDIA
    + boolean
    + default n
    +
    config MTD_NAND_ECC_SMC
    bool "NAND ECC Smart Media byte order"
    default n
    @@ -25,6 +29,11 @@ config MTD_NAND_ECC_SMC
    Software ECC according to the Smart Media Specification.
    The original Linux implementation had byte 0 and 1 swapped.

    +config MTD_SM_COMMON
    + select MTD_NAND_SMARTMEDIA
    + tristate
    + default n
    +
    config MTD_NAND_MUSEUM_IDS
    bool "Enable chip ids for obsolete ancient NAND devices"
    depends on MTD_NAND
    diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
    index 1407bd1..09891f6 100644
    --- a/drivers/mtd/nand/Makefile
    +++ b/drivers/mtd/nand/Makefile
    @@ -4,6 +4,7 @@

    obj-$(CONFIG_MTD_NAND) += nand.o nand_ecc.o
    obj-$(CONFIG_MTD_NAND_IDS) += nand_ids.o
    +obj-$(CONFIG_MTD_SM_COMMON) += sm_common.o

    obj-$(CONFIG_MTD_NAND_CAFE) += cafe_nand.o
    obj-$(CONFIG_MTD_NAND_SPIA) += spia.o
    diff --git a/drivers/mtd/nand/sm_common.c b/drivers/mtd/nand/sm_common.c
    new file mode 100644
    index 0000000..64d8ee0
    --- /dev/null
    +++ b/drivers/mtd/nand/sm_common.c
    @@ -0,0 +1,114 @@
    +/*
    + * Copyright (C) 2009 - Maxim Levitsky
    + * Common routines & support for xD format
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + */
    +#include <linux/kernel.h>
    +#include <linux/mtd/nand.h>
    +#include "sm_common.h"
    +
    +static struct nand_ecclayout nand_oob_sm = {
    + .eccbytes = 6,
    + .eccpos = {8, 9, 10, 13, 14, 15},
    + .oobfree = {
    + {.offset = 0 , .length = 4}, /* reserved */
    + {.offset = 6 , .length = 2}, /* LBA1 */
    + {.offset = 11, .length = 2} /* LBA2 */
    + }
    +};
    +
    +/* Tests if block (more correctly page) is bad */
    +static int sm_block_bad(struct mtd_info *mtd, loff_t ofs)
    +{
    + struct mtd_oob_ops ops;
    + struct sm_oob oob;
    + int ret;
    +
    + ops.mode = MTD_OOB_PLACE;
    + ops.ooboffs = 0;
    + ops.ooblen = SM_OOB_SIZE;
    + ops.oobbuf = (void *)&oob;
    + ops.datbuf = NULL;
    +
    + ret = mtd->read_oob(mtd, ofs, &ops);
    +
    + /* We can just assume that read error means bad block... */
    + if (ret < 0 || ops.oobretlen != SM_OOB_SIZE)
    + return 0;
    +
    + if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
    + return 1;
    +
    + return 0;
    +}
    +
    +/* Marks block as bad */
    +static int sm_block_markbad(struct mtd_info *mtd, loff_t ofs)
    +{
    + struct mtd_oob_ops ops;
    + struct sm_oob oob;
    + int ret, error = 0;
    +
    + memset(&oob, -1, SM_OOB_SIZE);
    + oob.data_status = 0;
    +
    + ops.mode = MTD_OOB_PLACE;
    + ops.ooboffs = 0;
    + ops.ooblen = SM_OOB_SIZE;
    + ops.oobbuf = (void *)&oob;
    + ops.datbuf = NULL;
    +
    +
    + ret = mtd->write_oob(mtd, ofs, &ops);
    + if (ret < 0 || ops.oobretlen != SM_OOB_SIZE) {
    + printk(KERN_NOTICE
    + "sm_common: can't mark sector at %i as bad\n",
    + (int)ofs);
    + error = -EIO;
    + } else
    + mtd->ecc_stats.badblocks++;
    +
    + return error;
    +}
    +
    +int sm_register_device(struct mtd_info *mtd)
    +{
    + struct nand_chip *chip = (struct nand_chip *)mtd->priv;
    + int ret;
    +
    + chip->options |= NAND_SKIP_BBTSCAN | NAND_SMARTMEDIA;
    +
    + /* Scan for card properties */
    + ret = nand_scan_ident(mtd, 1);
    +
    + if (ret)
    + return ret;
    +
    + /* Set oob handling functions. */
    + if (mtd->writesize == SM_SECTOR_SIZE) {
    + chip->block_bad = sm_block_bad;
    + chip->block_markbad = sm_block_markbad;
    + chip->ecc.layout = &nand_oob_sm;
    +
    + /* SmartMedia on small page nand, has page depedent oob layout,
    + thus let FTL do that hard job */
    + } else if (mtd->writesize != SM_SMALL_PAGE)
    + return -ENODEV;
    +
    + ret = nand_scan_tail(mtd);
    + if (ret)
    + return ret;
    +
    + ret = add_mtd_device(mtd);
    + if (ret)
    + return ret;
    + return 0;
    +}
    +EXPORT_SYMBOL_GPL(sm_register_device);
    +
    +MODULE_LICENSE("GPL");
    +MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
    +MODULE_DESCRIPTION("Common SmartMedia/xD functions");
    diff --git a/drivers/mtd/nand/sm_common.h b/drivers/mtd/nand/sm_common.h
    new file mode 100644
    index 0000000..2e6b517
    --- /dev/null
    +++ b/drivers/mtd/nand/sm_common.h
    @@ -0,0 +1,61 @@
    +/*
    + * Copyright (C) 2009 - Maxim Levitsky
    + * Common routines & support for SmartMedia/xD format
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + */
    +#include <linux/bitops.h>
    +#include <linux/mtd/mtd.h>
    +
    +/* Full oob structure as written on the flash */
    +struct sm_oob {
    + u32 reserved;
    + u8 data_status;
    + u8 block_status;
    + u8 lba_copy1[2];
    + u8 ecc2[3];
    + u8 lba_copy2[2];
    + u8 ecc1[3];
    +} __attribute__((packed));
    +
    +
    +/* one sector is always 512 bytes, but it can consist of two nand pages */
    +#define SM_SECTOR_SIZE 512
    +
    +/* oob area is also 16 bytes, but might be from two pages */
    +#define SM_OOB_SIZE 16
    +
    +/* This is maximum zone size, and all devices that have more that one zone
    + have this size */
    +#define SM_MAX_ZONE_SIZE 1024
    +
    +/* support for small page nand */
    +#define SM_SMALL_PAGE 256
    +#define SM_SMALL_OOB_SIZE 8
    +
    +
    +extern int sm_register_device(struct mtd_info *mtd);
    +
    +
    +inline int sm_sector_valid(struct sm_oob *oob)
    +{
    + return hweight16(oob->data_status) >= 5;
    +}
    +
    +inline int sm_block_valid(struct sm_oob *oob)
    +{
    + return hweight16(oob->block_status) >= 7;
    +}
    +
    +inline int sm_block_erased(struct sm_oob *oob)
    +{
    + static const u32 erased_pattern[4] = {
    + 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
    +
    + /* First test for erased block */
    + if (!memcmp(oob, erased_pattern, sizeof(*oob)))
    + return 1;
    + return 0;
    +}
    --
    1.6.3.3


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