diff options
| author | Ivan Djelic <ivan.djelic@parrot.com> | 2011-03-11 11:05:33 +0100 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2011-03-11 17:49:08 +0000 |
| commit | 193bd40026443835e1b96c79d5efe559d01509ae (patch) | |
| tree | 979bace7cd9806753c95867c6df89fe2de98fc73 /drivers/mtd/nand/nand_base.c | |
| parent | 89d8d32060de17c23f761df74799c7c07b79dd01 (diff) | |
mtd: nand: add software BCH ECC support
This patch adds software BCH ECC support to mtd, in order to handle recent
NAND device ecc requirements (4 bits or more).
It does so by adding a new ecc mode (NAND_ECC_SOFT_BCH) for use by board
drivers, and a new Kconfig option to enable BCH support. It relies on the
generic BCH library introduced in a previous patch.
When a board driver uses mode NAND_ECC_SOFT_BCH, it should also set fields
chip->ecc.size and chip->ecc.bytes to select BCH ecc data size and required
error correction capability. See nand_bch_init() documentation for details.
It has been tested on the following platforms using mtd-utils, UBI and
UBIFS: x86 (with nandsim), arm926ejs.
Signed-off-by: Ivan Djelic <ivan.djelic@parrot.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'drivers/mtd/nand/nand_base.c')
| -rw-r--r-- | drivers/mtd/nand/nand_base.c | 40 |
1 files changed, 39 insertions, 1 deletions
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index da760405034..85cfc061d41 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -42,6 +42,7 @@ #include <linux/mtd/mtd.h> #include <linux/mtd/nand.h> #include <linux/mtd/nand_ecc.h> +#include <linux/mtd/nand_bch.h> #include <linux/interrupt.h> #include <linux/bitops.h> #include <linux/leds.h> @@ -3248,7 +3249,7 @@ int nand_scan_tail(struct mtd_info *mtd) /* * If no default placement scheme is given, select an appropriate one */ - if (!chip->ecc.layout) { + if (!chip->ecc.layout && (chip->ecc.mode != NAND_ECC_SOFT_BCH)) { switch (mtd->oobsize) { case 8: chip->ecc.layout = &nand_oob_8; @@ -3351,6 +3352,40 @@ int nand_scan_tail(struct mtd_info *mtd) chip->ecc.bytes = 3; break; + case NAND_ECC_SOFT_BCH: + if (!mtd_nand_has_bch()) { + printk(KERN_WARNING "CONFIG_MTD_ECC_BCH not enabled\n"); + BUG(); + } + chip->ecc.calculate = nand_bch_calculate_ecc; + chip->ecc.correct = nand_bch_correct_data; + chip->ecc.read_page = nand_read_page_swecc; + chip->ecc.read_subpage = nand_read_subpage; + chip->ecc.write_page = nand_write_page_swecc; + chip->ecc.read_page_raw = nand_read_page_raw; + chip->ecc.write_page_raw = nand_write_page_raw; + chip->ecc.read_oob = nand_read_oob_std; + chip->ecc.write_oob = nand_write_oob_std; + /* + * Board driver should supply ecc.size and ecc.bytes values to + * select how many bits are correctable; see nand_bch_init() + * for details. + * Otherwise, default to 4 bits for large page devices + */ + if (!chip->ecc.size && (mtd->oobsize >= 64)) { + chip->ecc.size = 512; + chip->ecc.bytes = 7; + } + chip->ecc.priv = nand_bch_init(mtd, + chip->ecc.size, + chip->ecc.bytes, + &chip->ecc.layout); + if (!chip->ecc.priv) { + printk(KERN_WARNING "BCH ECC initialization failed!\n"); + BUG(); + } + break; + case NAND_ECC_NONE: printk(KERN_WARNING "NAND_ECC_NONE selected by board driver. " "This is not recommended !!\n"); @@ -3501,6 +3536,9 @@ void nand_release(struct mtd_info *mtd) { struct nand_chip *chip = mtd->priv; + if (chip->ecc.mode == NAND_ECC_SOFT_BCH) + nand_bch_free((struct nand_bch_control *)chip->ecc.priv); + #ifdef CONFIG_MTD_PARTITIONS /* Deregister partitions */ del_mtd_partitions(mtd); |