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From:   Alexander A Sverdlin <alexander.sverdlin@nokia.com>
To:     linux-mtd@lists.infradead.org
Cc:     Alexander Sverdlin <alexander.sverdlin@nokia.com>,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
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        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: [PATCH 1/2] mtd: spi-nor: Check for zero erase size in spi_nor_find_best_erase_type()
Date:   Fri, 19 Nov 2021 09:11:47 +0100
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From: Alexander Sverdlin <alexander.sverdlin@nokia.com>

Erase can be zeroed in spi_nor_parse_4bait() or
spi_nor_init_non_uniform_erase_map(). In practice it happened with
mt25qu256a, which supports 4K, 32K, 64K erases with 3b address commands,
but only 4K and 64K erase with 4b address commands.

Fixes: dc92843159a7 ("mtd: spi-nor: fix erase_type array to indicate current map conf")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
---
 drivers/mtd/spi-nor/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 88dd090..183ea9d 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1400,6 +1400,8 @@ spi_nor_find_best_erase_type(const struct spi_nor_erase_map *map,
 			continue;
 
 		erase = &map->erase_type[i];
+		if (!erase->opcode)
+			continue;
 
 		/* Alignment is not mandatory for overlaid regions */
 		if (region->offset & SNOR_OVERLAID_REGION &&
-- 
2.10.2