mtd:mxs:nand calculate ecc strength dynamically

Calculate ecc strength according oobsize, but not hardcoded
which is not aligned with kernel driver

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Signed-off-by: Ye.Li <b37916@freescale.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>

diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
index 2d2b938633c20260fbde12c50aa88cc3491b8c0d..fc5cf586c524ed888d13178aa9db60f696971105 100644 (file)
--- 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,