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From:   Allen-KH Cheng <allen-kh.cheng@mediatek.com>
To:     Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <pratyush@kernel.org>,
        Michael Walle <michael@walle.cc>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        <linux-mtd@lists.infradead.org>
CC:     <linux-spi@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        <Project_Global_Chrome_Upstream_Group@mediatek.com>,
        Allen-KH Cheng <allen-kh.cheng@mediatek.com>,
        Bayi Cheng <bayi.cheng@mediatek.com>
Subject: [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles
Date:   Mon, 31 Oct 2022 20:46:33 +0800
Message-ID: <20221031124633.13189-1-allen-kh.cheng@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

The number of bytes used by spi_nor_spimem_check_readop() may be
incorrect for the dummy cycles. Since nor->read_dummy is not initialized
before spi_nor_spimem_adjust_hwcaps().

We use both mode and wait state clock cycles instead of nor->read_dummy.

Fixes: 0e30f47232ab ("mtd: spi-nor: add support for DTR protocol")
Co-developed-by: Bayi Cheng <bayi.cheng@mediatek.com>
Signed-off-by: Bayi Cheng <bayi.cheng@mediatek.com>
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
---
 drivers/mtd/spi-nor/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 6c921eb3fadb..8b9c318a0ad4 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1914,7 +1914,8 @@ static int spi_nor_spimem_check_readop(struct spi_nor *nor,
 	spi_nor_spimem_setup_op(nor, &op, read->proto);
 
 	/* convert the dummy cycles to the number of bytes */
-	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
+	op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
+			  op.dummy.buswidth / 8;
 	if (spi_nor_protocol_is_dtr(nor->read_proto))
 		op.dummy.nbytes *= 2;
 
-- 
2.18.0