From 7d5929c1f34304ca5a970cfde8044053e56aa8c9 Mon Sep 17 00:00:00 2001 From: Roger Quadros Date: Mon, 25 Aug 2014 16:15:32 -0700 Subject: [PATCH] mtd: nand: omap: Revert to using software ECC by default For v3.12 and prior, 1-bit Hamming code ECC via software was the default choice. Commit c66d039197e4 in v3.13 changed the behaviour to use 1-bit Hamming code via Hardware using a different ECC layout i.e. (ROM code layout) than what is used by software ECC. This ECC layout change causes NAND filesystems created in v3.12 and prior to be unusable in v3.13 and later. So revert back to using software ECC by default if an ECC scheme is not explicitely specified. This defect can be observed on the following boards during legacy boot -omap3beagle -omap3touchbook -overo -am3517crane -devkit8000 -ldp -3430sdp Signed-off-by: Roger Quadros Tested-by: Grazvydas Ignotas Signed-off-by: Tony Lindgren --- arch/arm/mach-omap2/board-flash.c | 2 +- arch/arm/mach-omap2/gpmc-nand.c | 3 ++- drivers/mtd/nand/omap2.c | 14 +++++++++++--- include/linux/platform_data/mtd-nand-omap2.h | 13 +++++++++++-- 4 files changed, 25 insertions(+), 7 deletions(-) diff --git a/arch/arm/mach-omap2/board-flash.c b/arch/arm/mach-omap2/board-flash.c index e87f2a83d6bf..2d245c2e641c 100644 --- a/arch/arm/mach-omap2/board-flash.c +++ b/arch/arm/mach-omap2/board-flash.c @@ -142,7 +142,7 @@ __init board_nand_init(struct mtd_partition *nand_parts, u8 nr_parts, u8 cs, board_nand_data.nr_parts = nr_parts; board_nand_data.devsize = nand_type; - board_nand_data.ecc_opt = OMAP_ECC_HAM1_CODE_HW; + board_nand_data.ecc_opt = OMAP_ECC_HAM1_CODE_SW; gpmc_nand_init(&board_nand_data, gpmc_t); } #endif /* CONFIG_MTD_NAND_OMAP2 || CONFIG_MTD_NAND_OMAP2_MODULE */ diff --git a/arch/arm/mach-omap2/gpmc-nand.c b/arch/arm/mach-omap2/gpmc-nand.c index 8897ad7035fd..cb7764314f17 100644 --- a/arch/arm/mach-omap2/gpmc-nand.c +++ b/arch/arm/mach-omap2/gpmc-nand.c @@ -49,7 +49,8 @@ static bool gpmc_hwecc_bch_capable(enum omap_ecc ecc_opt) return 0; /* legacy platforms support only HAM1 (1-bit Hamming) ECC scheme */ - if (ecc_opt == OMAP_ECC_HAM1_CODE_HW) + if (ecc_opt == OMAP_ECC_HAM1_CODE_HW || + ecc_opt == OMAP_ECC_HAM1_CODE_SW) return 1; else return 0; diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index f0ed92e210a1..4dd617897eee 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -1794,9 +1794,12 @@ static int omap_nand_probe(struct platform_device *pdev) } /* populate MTD interface based on ECC scheme */ - nand_chip->ecc.layout = &omap_oobinfo; ecclayout = &omap_oobinfo; switch (info->ecc_opt) { + case OMAP_ECC_HAM1_CODE_SW: + nand_chip->ecc.mode = NAND_ECC_SOFT; + break; + case OMAP_ECC_HAM1_CODE_HW: pr_info("nand: using OMAP_ECC_HAM1_CODE_HW\n"); nand_chip->ecc.mode = NAND_ECC_HW; @@ -1848,7 +1851,7 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->ecc.priv = nand_bch_init(mtd, nand_chip->ecc.size, nand_chip->ecc.bytes, - &nand_chip->ecc.layout); + &ecclayout); if (!nand_chip->ecc.priv) { pr_err("nand: error: unable to use s/w BCH library\n"); err = -EINVAL; @@ -1923,7 +1926,7 @@ static int omap_nand_probe(struct platform_device *pdev) nand_chip->ecc.priv = nand_bch_init(mtd, nand_chip->ecc.size, nand_chip->ecc.bytes, - &nand_chip->ecc.layout); + &ecclayout); if (!nand_chip->ecc.priv) { pr_err("nand: error: unable to use s/w BCH library\n"); err = -EINVAL; @@ -2012,6 +2015,9 @@ static int omap_nand_probe(struct platform_device *pdev) goto return_error; } + if (info->ecc_opt == OMAP_ECC_HAM1_CODE_SW) + goto scan_tail; + /* all OOB bytes from oobfree->offset till end off OOB are free */ ecclayout->oobfree->length = mtd->oobsize - ecclayout->oobfree->offset; /* check if NAND device's OOB is enough to store ECC signatures */ @@ -2021,7 +2027,9 @@ static int omap_nand_probe(struct platform_device *pdev) err = -EINVAL; goto return_error; } + nand_chip->ecc.layout = ecclayout; +scan_tail: /* second phase scan */ if (nand_scan_tail(mtd)) { err = -ENXIO; diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h index 660c029d694f..16ec262dfcc8 100644 --- a/include/linux/platform_data/mtd-nand-omap2.h +++ b/include/linux/platform_data/mtd-nand-omap2.h @@ -21,8 +21,17 @@ enum nand_io { }; enum omap_ecc { - /* 1-bit ECC calculation by GPMC, Error detection by Software */ - OMAP_ECC_HAM1_CODE_HW = 0, + /* + * 1-bit ECC: calculation and correction by SW + * ECC stored at end of spare area + */ + OMAP_ECC_HAM1_CODE_SW = 0, + + /* + * 1-bit ECC: calculation by GPMC, Error detection by Software + * ECC layout compatible with ROM code layout + */ + OMAP_ECC_HAM1_CODE_HW, /* 4-bit ECC calculation by GPMC, Error detection by Software */ OMAP_ECC_BCH4_CODE_HW_DETECTION_SW, /* 4-bit ECC calculation by GPMC, Error detection by ELM */ -- 2.34.1