Re: [PATCH v4 1/3] mtd: spi-nor: Add the SNOR_F_4B_OPCODES flag

[Boris Brezillon <boris.brezillon@xxxxxxxxxxx>]

On Wed, 5 Dec 2018 17:32:54 +0100
Boris Brezillon <boris.brezillon@xxxxxxxxxxx> wrote:

> > >>> smaller than 16MB, doesn't mean it does not support 4B opcodes. We
> > >>> probably won't use the 4B opcodes in that case, but still.
> > >>>       
> > >>
> > >> I agree that manufacturers have a sense of humor and this might be possible. But
> > >> there's no need to use 4B opcodes in this case, so a post_sfdp fixup will help
> > >> here too.    
> > > 
> > > Except there's nothing to fix in this case, we just won't use 4B
> > > opcodes if we don't need to, that's all.    
> > 
> > you'll have an extra byte of address that has a tiny impact on performance on
> > small requests. I see it as a fix, we should do what's best to do. anyway ...  
> 
> No, see the checks that are done in this patch: to use 4B_CODES the
> flag should be set and the NOR should be larger than 16MB. The flag
> does not mean "use 4B opcodes", it meas "4B opMcodes are supported".

Maybe I should rename the flag SNOR_F_SUPPORTS_4B_OPCODES to make it
clear.

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