[PATCH 2/7] mtd: spi-nor: core: Report correct name in case of ID collisions

[Tudor.Ambarus at microchip.com]

On 7/5/21 4:13 PM, Pratyush Yadav wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 02/07/21 05:41PM, Tudor Ambarus wrote:
>> Provide a way to report the correct flash name in case of ID collisions.
>> There will be a single flash_info entry when flash IDs collide, and the
>> differentiation between the flash types will be made at runtime
>> if possible.
> 
> I am not sure if having one entry for all flashes with a collision is a
> good idea. For example, say we have one flash which supports SFDP and
> that's all we need for it. Another flash with the same ID does not
> support SFDP so it needs the SPI_NOR_DUAL_READ, etc. flags. How would
> you handle this case with the same entry? You would have to set all the
> flags in the disambiguation function. And nor->info is declared as const
> so you can't change the flags in there. Any code checking for
> info->flags would not work properly for these type of flashes. Wouldn't
> it be better to have multiple entries with the same ID and just pick the
> one we need in the disambiguation function?

Your scenario is hit in patches 3/7 and 4/7. In case of ID collisions between
a SFDP and a non-SFDP compliant flash, I propose to set SPI_NOR_PARSE_SFDP, as
well as all the other required flash info flags that statically init the flash.
The SFDP flash will init all its NOR flags at runtime, while the non-SFDP flash
will issue a RDSFDP command that will fail, and then it will init all the NOR
flags based on the flash info flags.

> 
> Anyway, if you do decide to go with this approach, comments below.

Right, thanks.