From patchwork Tue Jan 29 01:23:38 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v2] mtd: gpmi: add sanity check for the ECC Date: Mon, 28 Jan 2013 15:23:38 -0000 From: Huang Shijie X-Patchwork-Id: 216411 Message-Id: <1359422618-7185-1-git-send-email-b32955@freescale.com> To: Cc: Huang Shijie , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, dedekind1@gmail.com We do the check based on the following two facts: [1] The mx23/mx28 can only support 20-bits ECC, while the mx6 can supports 40-bits ECC. [2] The mx23/mx28 can only support the GF13, while the mx6 can supports GF13 and GF14. Signed-off-by: Huang Shijie --- v1 --> v2: [1] add the Golois Field check. [2] change the comments. --- drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 28 ++++++++++++++++++++++++++-- drivers/mtd/nand/gpmi-nand/gpmi-nand.h | 4 ++++ 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c index 2521678..717881a 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c @@ -94,6 +94,25 @@ static inline int get_ecc_strength(struct gpmi_nand_data *this) return round_down(ecc_strength, 2); } +static inline bool gpmi_check_ecc(struct gpmi_nand_data *this) +{ + struct bch_geometry *geo = &this->bch_geometry; + + /* Do the sanity check. */ + if (GPMI_IS_MX23(this) || GPMI_IS_MX28(this)) { + /* The mx23/mx28 only support the GF13. */ + if (geo->gf_len == 14) + return false; + + if (geo->ecc_strength > MXS_ECC_STRENGTH_MAX) + return false; + } else if (GPMI_IS_MX6Q(this)) { + if (geo->ecc_strength > MX6_ECC_STRENGTH_MAX) + return false; + } + return true; +} + int common_nfc_set_geometry(struct gpmi_nand_data *this) { struct bch_geometry *geo = &this->bch_geometry; @@ -123,8 +142,13 @@ int common_nfc_set_geometry(struct gpmi_nand_data *this) /* We use the same ECC strength for all chunks. */ geo->ecc_strength = get_ecc_strength(this); - if (!geo->ecc_strength) { - pr_err("wrong ECC strength.\n"); + if (!gpmi_check_ecc(this)) { + dev_err(this->dev, + "We can not support this nand chip." + " Its required ecc strength(%d) is beyond our" + " capability(%d).\n", geo->ecc_strength, + (GPMI_IS_MX6Q(this) ? MX6_ECC_STRENGTH_MAX + : MXS_ECC_STRENGTH_MAX)); return -EINVAL; } diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h index 3d93a5e..0729477 100644 --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h @@ -284,6 +284,10 @@ extern int gpmi_read_page(struct gpmi_nand_data *, #define STATUS_ERASED 0xff #define STATUS_UNCORRECTABLE 0xfe +/* BCH's bit correction capability. */ +#define MXS_ECC_STRENGTH_MAX 20 /* mx23 and mx28 */ +#define MX6_ECC_STRENGTH_MAX 40 + /* Use the platform_id to distinguish different Archs. */ #define IS_MX23 0x0 #define IS_MX28 0x1