linux-kernel - [PATCH v1] mtd: nand: Fix BBT update issue

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Date:   Tue, 16 Feb 2021 09:37:55 +0900
From:   Yoshio Furuyama <ytc-mb-yfuruyama7@...xia.com>
To:     miquel.raynal@...tlin.com, richard@....at, vigneshr@...com
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1] mtd: nand: Fix BBT update issue

Fixed issue of manages BBT (Bad Block Table).
It didn't mark correctly when a specific block was bad block.

This issue occurs when the bad block mark (3-bit chunk) is 
crosses over 32 bit (e.g. Block10, Block21...) unit.

Signed-off-by: Yoshio Furuyama <ytc-mb-yfuruyama7@...xia.com>
---
 drivers/mtd/nand/bbt.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/bbt.c b/drivers/mtd/nand/bbt.c
index 044adf913854..979c47e61381 100644
--- a/drivers/mtd/nand/bbt.c
+++ b/drivers/mtd/nand/bbt.c
@@ -112,18 +112,20 @@ int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
 			     ((entry * bits_per_block) / BITS_PER_LONG);
 	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
 	unsigned long val = status & GENMASK(bits_per_block - 1, 0);
+	unsigned long shift = ((bits_per_block + offs <= BITS_PER_LONG) ?
+					(offs + bits_per_block - 1) : (BITS_PER_LONG - 1));
 
 	if (entry >= nanddev_neraseblocks(nand))
 		return -ERANGE;
 
-	pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs);
+	pos[0] &= ~GENMASK(shift, offs);
 	pos[0] |= val << offs;
 
 	if (bits_per_block + offs > BITS_PER_LONG) {
 		unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
 
 		pos[1] &= ~GENMASK(rbits - 1, 0);
-		pos[1] |= val >> rbits;
+		pos[1] |= (val >> (BITS_PER_LONG - offs));
 	}
 
 	return 0;
-- 
2.25.1