Hi Roger,

On Tue, 19 Apr 2016 13:28:50 +0300
Roger Quadros [off-list ref] wrote:

quoted

@@ -1921,6 +1927,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 		nand_chip->ecc.correct          = omap_correct_data;
 		mtd_set_ooblayout(mtd, &omap_ooblayout_ops);
 		oobbytes_per_step		= nand_chip->ecc.bytes;
+
+		if (nand_chip->options & NAND_BUSWIDTH_16)
+			min_oobbytes		= 1;

Shouldn't this have been
		if (!(nand_chip->options & NAND_BUSWIDTH_16)
			min_oobbytes		= 1;
?

Yep.

quoted

 		break;
 
 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:

@@ -2038,10 +2047,8 @@ static int omap_nand_probe(struct platform_device *pdev)
 	}
 
 	/* check if NAND device's OOB is enough to store ECC signatures */
-	min_oobbytes = (oobbytes_per_step *
-			(mtd->writesize / nand_chip->ecc.size)) +
-		       (nand_chip->options & NAND_BUSWIDTH_16 ?
-			BADBLOCK_MARKER_LENGTH : 1);
+	min_oobbytes += (oobbytes_per_step *
+			 (mtd->writesize / nand_chip->ecc.size));
 	if (mtd->oobsize < min_oobbytes) {
 		dev_err(&info->pdev->dev,
 			"not enough OOB bytes required = %d, available=%d\n",

After the above changes BCH with HW ECC worked fine but BCH with SW ECC still failed.
I had to fix it up with the below patch. This is mainly because chip->ecc.steps wasn't
yet initialized before calling nand_bch_init().

After the below patch it worked fine with bch4 (hw & sw), bch8 (hw & sw) and ham1.
I couldn't yet verify bch16 though.

Thanks for the fix, but I'd prefer fixing the bug for all soft BCH
users.

Could you try this patch?

--->8---

diff --git a/drivers/mtd/nand/nand_bch.c b/drivers/mtd/nand/nand_bch.c
index ca9b2a4..3ca3d39 100644
--- a/drivers/mtd/nand/nand_bch.c
+++ b/drivers/mtd/nand/nand_bch.c

@@ -177,6 +177,16 @@ struct nand_bch_control *nand_bch_init(struct mtd_info *mtd)
 		goto fail;
 	}
 
+	/*
+	 * ecc->steps and ecc->total might be used by mtd->ooblayout->ecc(),
+	 * which is called by mtd_ooblayout_count_eccbytes().
+	 * Make sure they are properly initialized before calling
+	 * mtd_ooblayout_count_eccbytes().
+	 * FIXME: we should probaly rework the sequencing in nand_scan_tail()
+	 * to avoid setting those fields twice.
+	 */
+	nand->ecc.steps = eccsteps;
+	nand->ecc.total = eccsteps * eccbytes;
 	if (mtd_ooblayout_count_eccbytes(mtd) != (eccsteps*eccbytes)) {
 		printk(KERN_WARNING "invalid ecc layout\n");
 		goto fail;