Hello Anastasia,

Many thanks for your quick reply!

This needs to be designed... for example, what are the possible sizes
> of those smaller EEPROMs? can that be any size, or only a few standard
> options (like 256 and 512 bytes)?

Microchip has 128, 192, 256 and 512 byte EEPROMs (below 1024 bytes).

They do offer a DFP (bunch of XML device descriptors) from which the flash
descriptors could be generated.
--
Miklos

Anastasia Klimchuk <[email protected]> ezt írta (időpont: 2024. aug. 15.,
Cs, 14:50):

> Hello Miklos,
>
> I remember this, I was in a (somewhat) similar situation when I was
> writing unit tests. The total_size is in kilobytes and so the smallest
> size would be 1 kilobyte. While I only needed 16 bytes for test
> scenarios. The workaround for unit tests is to put 1 as total_size,
> then have 1024 bytes as a "total memory" but only really care about
> the first 16 bytes.
>
> I think you can try something in that direction. Something like, what
> if you put 1 as total_size (not 0), and then create a layout with one
> region of 512 bytes (or how much is real-total-size), and only operate
> on this region.
> Do you have a work in progress code that you could upload as a WIP
> patch? It might be easier to talk over the code.
>
> Both layout boundaries, and erase block sizes are measured in bytes,
> so they can be defined in an actual size.
>
> > Is supporting smaller EEPROMs considered a feature what could be merged
> at some point
>
> I think yes, why not merge a useful feature. If we figure out the
> working solution :)
>
> This needs to be designed... for example, what are the possible sizes
> of those smaller EEPROMs? can that be any size, or only a few standard
> options (like 256 and 512 bytes)?
>
> Maybe it can be a feature flag (FEATURE_MICRO256B or something like
> that), and then with this feature flag layout with 256 bytes region
> can be silently created.
>
> On Thu, Aug 15, 2024 at 12:10 AM Miklós Márton
> <[email protected]> wrote:
> >
> > Hello all,
> >
> > I tried to add support for some Microchip serial EEPROMs to being able
> to program them with an STLinkV3. I ran into problems with the smaller
> EEPROMs for e.g. 25LC040 which is only a 4Kbit device.
> >
> > The total_size in the flashchip structure is an unsigned int so I could
> only enter 0 as total size.
> >
> > In this case the flashrom shows the following message to me:
> > ERROR: Flash chip 25C040 erase function 0 region walking resulted in
> 0x000200 bytes total, expected 0x000000 bytes. Please report a bug at
> [email protected]
> > ERROR: Flash chip 25C040 erase function 0 is not in order. Please report
> a bug at [email protected]
> >
> > Is there any recommendations how to overcome on this?
> > Is supporting smaller EEPROMs considered a feature what could be merged
> at some point, or the flashrom is going to focus purely on flash memories?
> >
> > --
> > Miklos
> > _______________________________________________
> > flashrom mailing list -- [email protected]
> > To unsubscribe send an email to [email protected]
>
>
>
> --
> Anastasia.
>
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