+/*
+ * Check if the chip configuration meet the datasheet requirements.
+
+ * If our configuration corrects A bits per B bytes and the minimum
+ * required correction level is X bits per Y bytes, then we must ensure
+ * both of the following are true:
+ *
+ * (1) A / B >= X / Y
+ * (2) A >= X
+ *
+ * Requirement (1) ensures we can correct for the required bitflip density.
+ * Requirement (2) ensures we can correct even when all bitflips are clumped
+ * in the same sector.
+ */
+static bool nand_ecc_strength_good(struct mtd_info *mtd)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct nand_ecc_ctrl *ecc = &chip->ecc;
+ int corr, ds_corr;
+
+ if (ecc->size == 0 || chip->ecc_step_ds == 0)
+ /* Not enough information */
+ return true;
+
+ /*
+ * We get the number of corrected bits per page to compare
+ * the correction density.
+ */
+ corr = (mtd->writesize * ecc->strength) / ecc->size;
+ ds_corr = (mtd->writesize * chip->ecc_strength_ds) / chip->ecc_step_ds;
+
+ return corr >= ds_corr && ecc->strength >= chip->ecc_strength_ds;
+}