- uint32_t ecc_strength;
- ecc_strength = mxs_nand_get_ecc_strength(mtd->writesize, mtd->oobsize);
- return mxs_nand_get_mark_offset(mtd->writesize, ecc_strength) & 0x7;
+ /* The default for the length of Galois Field. */
+ geo->gf_len = 13;
+
+ /* The default for chunk size. */
+ geo->ecc_chunk_size = 512;
+
+ if (geo->ecc_chunk_size < mtd->oobsize) {
+ geo->gf_len = 14;
+ geo->ecc_chunk_size *= 2;
+ }
+
+ if (mtd->oobsize > geo->ecc_chunk_size) {
+ printf("Not support the NAND chips whose oob size is larger then %d bytes!\n",
+ geo->ecc_chunk_size);
+ return -EINVAL;
+ }
+
+ geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size;
+
+ /*
+ * 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)
+ */
+ geo->ecc_strength = ((mtd->oobsize - MXS_NAND_METADATA_SIZE) * 8)
+ / (geo->gf_len * geo->ecc_chunk_count);
+
+ geo->ecc_strength = min(round_down(geo->ecc_strength, 2),
+ mxs_nand_max_ecc_strength_supported());
+
+ return 0;