From bd38da1a558ea31f2dee4a14a972333b68bfa0ee Mon Sep 17 00:00:00 2001 From: Peng Fan Date: Wed, 15 Apr 2015 09:27:21 +0200 Subject: [PATCH] mtd:mxs:nand calculate ecc strength dynamically MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Calculate ecc strength according oobsize, but not hardcoded which is not aligned with kernel driver Signed-off-by: Peng Fan Signed-off-by: Ye.Li Reviewed-by: Marek Vasut Signed-off-by: Jörg Krause --- drivers/mtd/nand/mxs_nand.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c index 2d2b938633..fc5cf586c5 100644 --- a/drivers/mtd/nand/mxs_nand.c +++ b/drivers/mtd/nand/mxs_nand.c @@ -146,26 +146,20 @@ static uint32_t mxs_nand_aux_status_offset(void) static inline uint32_t mxs_nand_get_ecc_strength(uint32_t page_data_size, uint32_t page_oob_size) { - if (page_data_size == 2048) { - if (page_oob_size == 64) - return 8; + int ecc_strength; - if (page_oob_size == 112) - return 14; - } - - if (page_data_size == 4096) { - if (page_oob_size == 128) - return 8; - - if (page_oob_size == 218) - return 16; - - if (page_oob_size == 224) - return 16; - } + /* + * Determine the ECC layout with the formula: + * ECC bits per chunk = (total page spare data bits) / + * (bits per ECC level) / (chunks per page) + * where: + * total page spare data bits = + * (page oob size - meta data size) * (bits per byte) + */ + ecc_strength = ((page_oob_size - MXS_NAND_METADATA_SIZE) * 8) + / (13 * mxs_nand_ecc_chunk_cnt(page_data_size)); - return 0; + return round_down(ecc_strength, 2); } static inline uint32_t mxs_nand_get_mark_offset(uint32_t page_data_size, -- 2.30.2