[PATCH] mtd: spi-nor: Skip erase logic when SPI_NOR_NO_ERASE is set

[PATCH] mtd: spi-nor: Skip erase logic when SPI_NOR_NO_ERASE is set

[Tudor Ambarus]

Even if SPI_NOR_NO_ERASE was set, one could still send erase opcodes
to the flash. It is not recommended to send unsupported opcodes to
flashes. Fix the logic and do not set mtd->_erase when SPI_NOR_NO_ERASE
is specified. With this users will not be able to issue erase opcodes to
flashes and instead they will recive an -ENOTSUPP error.

Cc: stable@vger.kernel.org
Fixes: b199489d37b2 ("mtd: spi-nor: add the framework for SPI NOR")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.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 86a536c97c18..cd2d094ef837 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -2969,10 +2969,11 @@ static void spi_nor_set_mtd_info(struct spi_nor *nor)
 	mtd->flags = MTD_CAP_NORFLASH;
 	if (nor->info->flags & SPI_NOR_NO_ERASE)
 		mtd->flags |= MTD_NO_ERASE;
+	else
+		mtd->_erase = spi_nor_erase;
 	mtd->writesize = nor->params->writesize;
 	mtd->writebufsize = nor->params->page_size;
 	mtd->size = nor->params->size;
-	mtd->_erase = spi_nor_erase;
 	mtd->_read = spi_nor_read;
 	/* Might be already set by some SST flashes. */
 	if (!mtd->_write)
-- 
2.25.1

Re: [PATCH] mtd: spi-nor: Skip erase logic when SPI_NOR_NO_ERASE is set

[Michael Walle]

Am 2022-02-28 17:33, schrieb Tudor Ambarus:
> Even if SPI_NOR_NO_ERASE was set, one could still send erase opcodes
> to the flash. It is not recommended to send unsupported opcodes to
> flashes. Fix the logic and do not set mtd->_erase when SPI_NOR_NO_ERASE
> is specified. With this users will not be able to issue erase opcodes 
> to
> flashes and instead they will recive an -ENOTSUPP error.

But why is there an erase opcode and erase size set in the
first place? spi_nor_select_erase() should probably return
early if SPI_NOR_NO_ERASE is set. Not setting the erasesize
would also return -ENOTSUPP. I prefer this one for a fixes
patch, though. But spi_nor_select_erase() should also be
fixed.

Reviewed-by: Michael Walle <michael@walle.cc>

> 
> Cc: stable@vger.kernel.org
> Fixes: b199489d37b2 ("mtd: spi-nor: add the framework for SPI NOR")
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.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 86a536c97c18..cd2d094ef837 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -2969,10 +2969,11 @@ static void spi_nor_set_mtd_info(struct spi_nor 
> *nor)
>  	mtd->flags = MTD_CAP_NORFLASH;
>  	if (nor->info->flags & SPI_NOR_NO_ERASE)
>  		mtd->flags |= MTD_NO_ERASE;
> +	else
> +		mtd->_erase = spi_nor_erase;
>  	mtd->writesize = nor->params->writesize;
>  	mtd->writebufsize = nor->params->page_size;
>  	mtd->size = nor->params->size;
> -	mtd->_erase = spi_nor_erase;
>  	mtd->_read = spi_nor_read;
>  	/* Might be already set by some SST flashes. */
>  	if (!mtd->_write)

Re: [PATCH] mtd: spi-nor: Skip erase logic when SPI_NOR_NO_ERASE is set

[Tudor Ambarus]

On Mon, 28 Feb 2022 18:33:34 +0200, Tudor Ambarus wrote:
> Even if SPI_NOR_NO_ERASE was set, one could still send erase opcodes
> to the flash. It is not recommended to send unsupported opcodes to
> flashes. Fix the logic and do not set mtd->_erase when SPI_NOR_NO_ERASE
> is specified. With this users will not be able to issue erase opcodes to
> flashes and instead they will recive an -ENOTSUPP error.

Applied to spi-nor/next, thanks!

[1/1] mtd: spi-nor: Skip erase logic when SPI_NOR_NO_ERASE is set
      https://git.kernel.org/mtd/c/151c6b49d679

Best regards,
-- 
Tudor Ambarus <tudor.ambarus@microchip.com>