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authorDmitry Lavnikevich <d.lavnikevich@sam-solutions.com>2014-03-10 14:39:53 +0300
committerSascha Hauer <s.hauer@pengutronix.de>2014-03-12 21:26:37 +0100
commit3676454f5cb571fe1370d3d8f9b67704c08cb9b3 (patch)
tree15ffc664f67aa34e3726aba661cedb9868d211df
parentc15680099e23142d1a04cab99cf88212c7ad3404 (diff)
downloadbarebox-3676454f5cb571fe1370d3d8f9b67704c08cb9b3.tar.gz
nand: mxs: Fix for calculating ecc strength on some types of NAND flash
Was tested on NAND with {writesize=4096, oobsize=224} and {writesize=2048, oobsize=64}. This patch will not break any NAND that was working before. Implemented calculation way may be used for other NAND chips with writesize == 2048 but oobsize != 64. Signed-off-by: Dmitry Lavnikevich <d.lavnikevich@sam-solutions.com> Signed-off-by: Grigory Milev <g.milev@sam-solutions.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
-rw-r--r--drivers/mtd/nand/nand_mxs.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/drivers/mtd/nand/nand_mxs.c b/drivers/mtd/nand/nand_mxs.c
index 237a423..b06b558 100644
--- a/drivers/mtd/nand/nand_mxs.c
+++ b/drivers/mtd/nand/nand_mxs.c
@@ -234,18 +234,31 @@ 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)
{
+ int ecc_chunk_count = mxs_nand_ecc_chunk_cnt(page_data_size);
+ int ecc_strength = 0;
+ int gf_len = 13; /* length of Galois Field for non-DDR nand */
+
+ /*
+ * Possibly this if-else calculation may be removed since
+ * ecc_strength calculated after it is taken from kernel driver
+ * and therefore should work for all cases. But it was tested only
+ * on devices with {data_size = 2046, oob_size = 64} and
+ * {data_size = 4096, oob_size = 224} configuration.
+ */
if (page_data_size == 2048)
return 8;
-
- if (page_data_size == 4096) {
+ else if (page_data_size == 4096) {
if (page_oob_size == 128)
return 8;
-
if (page_oob_size == 218)
return 16;
}
- return 0;
+ ecc_strength = ((page_oob_size - MXS_NAND_METADATA_SIZE) * 8)
+ / (gf_len * ecc_chunk_count);
+
+ /* We need the minor even number. */
+ return rounddown(ecc_strength, 2);
}
static inline uint32_t mxs_nand_get_mark_offset(uint32_t page_data_size,