From 85f152f182436302dcc2f538e733bb67620643ee Mon Sep 17 00:00:00 2001 From: Cheng Ming Lin Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] mtd: spi-nor: core: replace dummy buswidth from addr to data BugLink: https://bugs.launchpad.net/bugs/2101915 commit 98d1fb94ce75f39febd456d6d3cbbe58b6678795 upstream. The default dummy cycle for Macronix SPI NOR flash in Octal Output Read Mode(1-1-8) is 20. Currently, the dummy buswidth is set according to the address bus width. In the 1-1-8 mode, this means the dummy buswidth is 1. When converting dummy cycles to bytes, this results in 20 x 1 / 8 = 2 bytes, causing the host to read data 4 cycles too early. Since the protocol data buswidth is always greater than or equal to the address buswidth. Setting the dummy buswidth to match the data buswidth increases the likelihood that the dummy cycle-to-byte conversion will be divisible, preventing the host from reading data prematurely. Fixes: 0e30f47232ab ("mtd: spi-nor: add support for DTR protocol") Cc: stable@vger.kernel.org Reviewed-by: Pratyush Yadav Signed-off-by: Cheng Ming Lin Link: https://lore.kernel.org/r/20241112075242.174010-2-linchengming884@gmail.com Signed-off-by: Tudor Ambarus Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/mtd/spi-nor/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index 4129764fad8c..cbfe639a5d84 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -89,7 +89,7 @@ void spi_nor_spimem_setup_op(const struct spi_nor *nor, op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto); if (op->dummy.nbytes) - op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto); + op->dummy.buswidth = spi_nor_get_protocol_data_nbits(proto); if (op->data.nbytes) op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);