linux-kernel - [PATCH v2] mtd: spi-nor: Return error when nor->addr

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Date:   Wed, 13 Mar 2019 21:45:53 +0800
From:   Liu Xiang <liu.xiang6@....com.cn>
To:     bbrezillon@...nel.org
Cc:     marek.vasut@...il.com, dwmw2@...radead.org,
        computersforpeace@...il.com, richard@....at,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        liuxiang_1999@....com, Liu Xiang <liu.xiang6@....com.cn>
Subject: [PATCH v2] mtd: spi-nor: Return error when nor->addr_width does not match the device size

In some is25lp256, the DWORD1 of JEDEC Basic Flash Parameter Header
is 0xfff920e5. So the DWORD1[18:17] Address Bytes bits are 0b00,
means that 3-Byte only addressing. But the device size is larger
than 16MB, nor->addr_width must be 4 to access the whole address.
An error should be returned when nor->addr_width does not match
the device size in spi_nor_parse_bfpt(). Then it can go back to
use spi_nor_ids[] for setting the right addr_width.

Suggested-by: Boris Brezillon <boris.brezillon@...tlin.com>
Signed-off-by: Liu Xiang <liu.xiang6@....com.cn>
---
 drivers/mtd/spi-nor/spi-nor.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 6e13bbd..63933c7 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2811,6 +2811,14 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 	}
 	params->size >>= 3; /* Convert to bytes. */
 
+	/*
+	 * If the device exceeds 16MiB, addr_width must be 4.
+	 * addr_width == 3 means the Address Bytes we are
+	 * reading from BFPT is wrong.
+	 */
+	if (params->size > 0x1000000 && nor->addr_width == 3)
+		return -EINVAL;
+
 	/* Fast Read settings. */
 	for (i = 0; i < ARRAY_SIZE(sfdp_bfpt_reads); i++) {
 		const struct sfdp_bfpt_read *rd = &sfdp_bfpt_reads[i];
-- 
1.9.1