From f7f8c1756e9a5f1258a7cc6b663f8451b724900f Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Wed, 5 Jul 2017 08:51:09 +0200 Subject: [PATCH] nand: fix wrong default oob layout for small pages using soft ecc When using soft ecc, if no ooblayout is given, the core automatically uses one of the nand_ooblayout_{sp,lp}*() functions to determine the layout inside the out of band data. Until kernel version 4.6, struct nand_ecclayout was used for that purpose. During the migration from 4.6 to 4.7, an error shown up in the small page layout, in the case oob section is only 8 bytes long. The layout was using three bytes (0, 1, 2) for ecc, two bytes (3, 4) as free bytes, one byte (5) for bad block marker and finally two bytes (6, 7) as free bytes, as shown there: [linux-4.6] drivers/mtd/nand/nand_base.c:52 static struct nand_ecclayout nand_oob_8 = { .eccbytes = 3, .eccpos = {0, 1, 2}, .oobfree = { {.offset = 3, .length = 2}, {.offset = 6, .length = 2} } }; This fixes the current implementation which is incoherent. It references bit 3 at the same time as an ecc byte and a free byte. Furthermore, it is clear with the previous implementation that there is only one ecc section with 8 bytes oob sections. We shall return -ERANGE in the nand_ooblayout_ecc_sp() function when asked for the second section. Signed-off-by: Miquel Raynal Fixes: 41b207a70d3a ("mtd: nand: implement the default mtd_ooblayout_ops") Cc: Signed-off-by: Boris Brezillon --- drivers/mtd/nand/nand_base.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 5fa5ddc94834..7b3826b42447 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -65,8 +65,14 @@ static int nand_ooblayout_ecc_sp(struct mtd_info *mtd, int section, if (!section) { oobregion->offset = 0; - oobregion->length = 4; + if (mtd->oobsize == 16) + oobregion->length = 4; + else + oobregion->length = 3; } else { + if (mtd->oobsize == 8) + return -ERANGE; + oobregion->offset = 6; oobregion->length = ecc->total - 4; } -- 2.20.1