mtd: spi-nor: Fix the number of bytes for the dummy cycles

[ Upstream commit fdc20370d93e8c6d2f448a539d08c2c064af7694 ]

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>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Tested-by: Dhruva Gole <d-gole@ti.com>
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Link: https://lore.kernel.org/r/20221031124633.13189-1-allen-kh.cheng@mediatek.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index bee8fc4..0cf1a17 100644 (file)
--- 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;