2022-10-31 13:27:30

by Allen-KH Cheng

Subject: [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles

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 <[email protected]>
Signed-off-by: Bayi Cheng <[email protected]>
Signed-off-by: Allen-KH Cheng <[email protected]>
---
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

2022-10-31 15:12:45

by Dhruva Gole

Subject: Re: [EXTERNAL] [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles

On 31/10/22 18:16, Allen-KH Cheng wrote:
> 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 <[email protected]>
> Signed-off-by: Bayi Cheng <[email protected]>
> Signed-off-by: Allen-KH Cheng <[email protected]>
> ---

Tested-by: Dhruva Gole <[email protected]>

> 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;
>
Tested on my AM625 SK EVM having spi nor flash and no obvious
regressions observed :)

--
Best regards,
Dhruva Gole
Texas Instruments Incorporated

2022-11-02 12:34:59

by AngeloGioacchino Del Regno

Subject: Re: [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles

Il 31/10/22 13:46, Allen-KH Cheng ha scritto:
> 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 <[email protected]>
> Signed-off-by: Bayi Cheng <[email protected]>
> Signed-off-by: Allen-KH Cheng <[email protected]>
> Tested-by: Dhruva Gole <[email protected]>

On MT8195 Tomato Chromebook:
Tested-by: AngeloGioacchino Del Regno <[email protected]>

2022-11-06 23:09:31

by Pratyush Yadav

Subject: Re: [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles

On 31/10/22 08:46PM, Allen-KH Cheng wrote:
> 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 <[email protected]>
> Signed-off-by: Bayi Cheng <[email protected]>
> Signed-off-by: Allen-KH Cheng <[email protected]>
> ---
> 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;

Good catch!

Reviewed-by: Pratyush Yadav <[email protected]>

> if (spi_nor_protocol_is_dtr(nor->read_proto))
> op.dummy.nbytes *= 2;
>
> --
> 2.18.0
>

--
Regards,
Pratyush Yadav

2022-11-21 15:32:59

by Tudor Ambarus

Subject: Re: [PATCH] mtd: spi-nor: Fix the number of bytes for the dummy cycles

On Mon, 31 Oct 2022 20:46:33 +0800, Allen-KH Cheng wrote:
> 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.
>
>
> [...]

Applied to spi-nor/next, thanks!

[1/1] mtd: spi-nor: Fix the number of bytes for the dummy cycles
https://git.kernel.org/mtd/c/fdc20370d93e

Best regards,
--
Tudor Ambarus <[email protected]>