From: Cheng Ming Lin chengminglin@mxic.com.tw
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: 0e30f47232ab5 ("mtd: spi-nor: add support for DTR protocol") Cc: stable@vger.kernel.org Reviewd-by: Pratyush Yadav pratyush@kernel.org Signed-off-by: Cheng Ming Lin chengminglin@mxic.com.tw --- 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 f9c189ed7353..c7aceaa8a43f 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);