Re: [PATCH v2 01/35] mtd: spi-nor: core: Introduce SPI_NOR_PARSE_SFDP

Michael Walle
2021-08-23T22:19:03Z

Am 2021-07-27 06:51, schrieb Tudor Ambarus:
> SPI NOR flashes that statically declare one of the
> SPI_NOR_{DUAL, QUAD, OCTAL, OCTAL_DTR}_READ flags and do not support
> the RDSFDP command are gratuiously receiving the RDSFDP command
> in the attempt of parsing the SFDP tables. It is not desirable to issue
> commands that are not supported, so introduce a flag to help on this
> situation.
>
> New flash additions that support the SFDP standard should be declared
> using SPI_NOR_PARSE_SFDP. Support that can be discovered when parsing
> SFDP should not be duplicated by explicit flags at flash declaration.
> All the flash parameters will be discovered when parsing SFDP.
> Sometimes manufacturers wrongly define some fields in the SFDP tables.
> If that's the case, SFDP data can be amended with the fixups() hooks.
> It is not common, but if the SFDP tables are entirely wrong, and it
> does not worth the hassle to tweak the SFDP parameters by using the
> fixups hooks, or if the flash does not define the SFDP tables at all,
> then statically init the flash with the SPI_NOR_SKIP_SFDP flag and
> specify the rest of flash capabilities with the flash info flags.
>
> With time, we want to convert all flashes to SPI_NOR_PARSE_SFDP and
> stop triggering the SFDP parsing with the
> SPI_NOR_{DUAL, QUAD, OCTAL*}_READ flags. Getting rid of the
> SPI_NOR_{OCTAL, OCTAL_DTR}_READ trigger is easily achievable, the rest
> are a long term goal.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> Reviewed-by: Heiko Thiery <heiko.thiery@gmail.com>

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