linux-kernel - [PATCH] mtd: spinand: Fix ECC status and OOB layout for Toshiba TC58CVG2S0H

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Date:   Wed, 28 Nov 2018 12:13:31 +0000
From:   Schrempf Frieder <frieder.schrempf@...tron.de>
To:     "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "peron.clem@...il.com" <peron.clem@...il.com>,
        Schrempf Frieder <frieder.schrempf@...tron.de>,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>
Subject: [PATCH] mtd: spinand: Fix ECC status and OOB layout for Toshiba
 TC58CVG2S0H

When reading the status of the on-chip ECC, the Toshiba chip returns
two different states for reporting corrected bitflips. We should check
for both of them.

Also the datasheet claims that the ECC bytes in OOB should not be
accessed at all, so let's also avoid any read operations on them.

One more minor optimization is to return the free OOB bytes as one
continuous area, instead of multiple sections.

Suggested-by: Clément Péron <peron.clem@...il.com>
Signed-off-by: Frieder Schrempf <frieder.schrempf@...tron.de>
---
 drivers/mtd/nand/spi/toshiba.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/nand/spi/toshiba.c b/drivers/mtd/nand/spi/toshiba.c
index 294bcf6..9040aa5 100644
--- a/drivers/mtd/nand/spi/toshiba.c
+++ b/drivers/mtd/nand/spi/toshiba.c
@@ -11,6 +11,7 @@
 #include <linux/mtd/spinand.h>
 
 #define SPINAND_MFR_TOSHIBA		0x98
+#define TOSH_STATUS_ECC_HAS_BITFLIPS_T	(3 << 4)
 
 static SPINAND_OP_VARIANTS(read_cache_variants,
 		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
@@ -27,25 +28,17 @@ static SPINAND_OP_VARIANTS(update_cache_variants,
 static int tc58cvg2s0h_ooblayout_ecc(struct mtd_info *mtd, int section,
 				     struct mtd_oob_region *region)
 {
-	if (section > 7)
-		return -ERANGE;
-
-	region->offset = 128 + 16 * section;
-	region->length = 16;
-
-
-	return 0;
+	return -ERANGE;
 }
 
 static int tc58cvg2s0h_ooblayout_free(struct mtd_info *mtd, int section,
 				      struct mtd_oob_region *region)
 {
-	if (section > 7)
+	if (section > 0)
 		return -ERANGE;
 
-	region->offset = 2 + 16 * section;
-	region->length = 14;
-
+	region->offset = 2;
+	region->length = 126;
 
 	return 0;
 }
@@ -70,6 +63,7 @@ static int tc58cvg2s0h_ecc_get_status(struct spinand_device *spinand,
 		return -EBADMSG;
 
 	case STATUS_ECC_HAS_BITFLIPS:
+	case TOSH_STATUS_ECC_HAS_BITFLIPS_T:
 		/*
 		 * Let's try to retrieve the real maximum number of bitflips
 		 * in order to avoid forcing the wear-leveling layer to move
-- 
2.7.4