Re: [PATCH v4 2/6] mtd: spi-nor: core: Handle ID collisions between SFDP & non-SFDP flashes

[Michael Walle <michael@walle.cc>]

Am 2022-02-28 14:45, schrieb Tudor Ambarus:
> A typical differentiator between flashes whose ID collide is whether 
> they
> support SFDP or not. For such a collision there will be a single
> flash_info entry where the developer should specify:
> 1/ PARSE_SFDP - so that the flash that supports SFDP to initialize its
>    parameters by parsing the SFDP tables
> 2/ any of the no_sfdp_flags less SPI_NOR_SKIP_SFDP, to initialize the
>    flash parameters via the static no_sfdp_flags for the flash that
>    doesn't support SFDP.
> Use the logic the above to handle ID collisions between SFDP & non-SFDP
> flashes.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
>  drivers/mtd/spi-nor/core.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index fbf3278ba29a..aef00151c116 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -2639,8 +2639,17 @@ static int spi_nor_init_params(struct spi_nor 
> *nor)
>  	if (nor->info->parse_sfdp) {
>  		ret = spi_nor_parse_sfdp(nor);

Can we return -ENOENT here if sfdp isn't supported, so we
can differentiate between "no sfdp present" and other errors?

>  		if (ret) {
> -			dev_err(nor->dev, "BFPT parsing failed. Please consider using
> SPI_NOR_SKIP_SFDP when declaring the flash\n");
> -			return ret;
> +			/*
> +			 * Handle ID collisions between flashes that support
> +			 * SFDP and flashes that don't. Initialize parameters
> +			 * for the flash that doesn't support SFDP.
> +			 */
> +			if (nor->info->no_sfdp_flags & ~SPI_NOR_SKIP_SFDP) {

Shouldn't this be
if (!(nor->info->no_sfdp_flags & SPI_NOR_SKIP_SFDP))

> +				spi_nor_no_sfdp_init_params(nor);
> +			} else {
> +				dev_err(nor->dev, "BFPT parsing failed. Please consider using
> SPI_NOR_SKIP_SFDP when declaring the flash\n");
> +				return ret;
> +			}
>  		}
>  	} else if (nor->info->no_sfdp_flags & SPI_NOR_SKIP_SFDP) {
>  		spi_nor_no_sfdp_init_params(nor);

-michael

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