at91: PMECC: enable PMECC in dt for at91sam9x5ek, at91sam9n12ek

index c516a94..b50283a 100644
@@ -908,6 +908,84 @@ static void atmel_pmecc_core_init(struct mtd_info *mtd)
 	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
 }
 
+/*
+ * Get ECC requirement in ONFI parameters, returns -1 if ONFI
+ * parameters is not supported.
+ * return 0 if success to get the ECC requirement.
+ */
+static int get_onfi_ecc_param(struct nand_chip *chip,
+		int *ecc_bits, int *sector_size)
+{
+	*ecc_bits = *sector_size = 0;
+
+	if (chip->onfi_params.ecc_bits == 0xff)
+		/* TODO: the sector_size and ecc_bits need to be find in
+		 * extended ecc parameter, currently we don't support it.
+		 */
+		return -1;
+
+	*ecc_bits = chip->onfi_params.ecc_bits;
+
+	/* The default sector size (ecc codeword size) is 512 */
+	*sector_size = 512;
+
+	return 0;
+}
+
+/*
+ * Choose ecc cap and sector size in atmel_nand_host according to ONFI
+ * parameters ecc requirement.
+ * return 0 if success. otherwise return error code.
+ */
+static int pmecc_choose_ecc_bits(struct atmel_nand_host *host,
+		struct nand_chip *chip)
+{
+	int ecc_bits, sector_size;
+
+	if (!get_onfi_ecc_param(chip, &ecc_bits, &sector_size)) {
+		dev_info(host->dev, "ONFI params, minimum required ECC: %dbits in %d bytes\n",
+				ecc_bits, sector_size);
+
+		if (ecc_bits > host->pmecc_corr_cap) {
+			dev_err(host->dev, "Error: Need to set a bigger pmecc-cap in dts. Current is: %d\n",
+				host->pmecc_corr_cap);
+			return -EINVAL;
+		}
+		if (sector_size < host->pmecc_sector_size) {
+			dev_err(host->dev, "Error: Need to set a smaller pmecc-sector-size in dts. Current is: %d\n",
+					host->pmecc_sector_size);
+			return -EINVAL;
+		}
+
+		/* use the most fitable ecc bits (the near bigger one ) */
+		if (ecc_bits <= 2)
+			host->pmecc_corr_cap = 2;
+		else if (ecc_bits <= 4)
+			host->pmecc_corr_cap = 4;
+		else if (ecc_bits < 8)
+			host->pmecc_corr_cap = 8;
+		else if (ecc_bits < 12)
+			host->pmecc_corr_cap = 12;
+		else if (ecc_bits < 24)
+			host->pmecc_corr_cap = 24;
+		else
+			return -EINVAL;
+
+		/* use the most fitable sector size (the near smaller one ) */
+		if (sector_size >= 1024)
+			host->pmecc_sector_size = 1024;
+		else if (sector_size >= 512)
+			host->pmecc_sector_size = 512;
+		else
+			return -EINVAL;
+	} else {
+		dev_info(host->dev,
+		"NAND chip ECC reqirement is in Extended ONFI parameter, we don't support yet. So use default setting in dts\n");
+	}
+
+	return 0;
+}
+
 static int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
 					 struct atmel_nand_host *host)
 {

@@ -916,8 +994,19 @@ static int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
 	struct resource *regs, *regs_pmerr, *regs_rom;
 	int cap, sector_size, err_no;
 
+	if (nand_chip->onfi_version) {
+		/* Choose ecc cap and sector size base on ONFI parameters */
+		err_no = pmecc_choose_ecc_bits(host, nand_chip);
+		if (err_no)
+			return err_no;
+	} else {
+		dev_info(host->dev, "NAND chip is not ONFI compliant, assume ecc_bits is 2");
+		host->pmecc_corr_cap = 2;
+	}
+
 	cap = host->pmecc_corr_cap;
 	sector_size = host->pmecc_sector_size;
+
 	dev_info(host->dev, "Initialize PMECC params, cap: %d, sector: %d\n",
 		 cap, sector_size);