On 18.11.2010 21:14, Richard A. Smith wrote:I see. On x86, you would only want to program the upper 64k.
> On 11/18/2010 12:48 PM, Carl-Daniel Hailfinger wrote:
>
>> On 18.11.2010 16:51, Richard Smith wrote:
>>> Current flashrom forces that the loaded filesize must equal the
>>> romsize. If you are using an external programmer then this may not be
>>> true.
>>
>> Can you give an example use case?
>
> Certainly since I'm exactly this case. The EnE EC chips that I use
> KB3700,KB3930 have an address space of 64k. However, these parts can
> share space with the system firmware and the EC itself can use an SPI
> part that is much bigger (I forget exactly how big) The OLPC system
> used an 8Mbit part on both XO-1 and 1.5.
>
> When doing EC work I'm only interested int the lower 64k and thats the
> size of file my build system generates. The 64k blob gets sucked into
> the larger firmware image when we build the system firmware.
>
> On the XO 1.75 the EC has its own SPI flash but you can't get a 64k
> SPI flash so its 128k.
>
> When I want to program the EC directly with a programmer I only want
> to program the lower 64k.
This would introduce breakage for the main use case of flashrom: x86
> Since my generated files are 64k in size flashrom won't load them
> unless I change my build system to generate files that match the size.
>
>>> How deeply wired is this assumption? I'd like to bypass those checks
>>> it if the -p option is used.
>>>
>>
>> The underlying problem is that flashrom can't know if you want
>> top-aligned or bottom-aligned write. If you only want to write a part of
>> the chip, you can do that with the layout feature, but that still
>> requires an image file with full size. Suggestions are welcome on how
>> flashrom should detect the alignment wanted by the user. (The famous
>> "DoWhatIMean" function has not been implemented yet.)
>
> The answer is don't try to guess. Always use bottom aligned.
BIOS. If you flash a smaller image to an x86 BIOS chip, it must always
be top aligned.
It may be expected by people working with programmers, but how can we
> Thats what the --offset command is for. Every programmer I've used
> for the last 20 years (probably about 10) works this way. Its
> expected and intuitive. You feed it a file and a chip type (if it
> can't autodetect) and it just programs that data starting at address
> zero.
tell x86 users with no standalone programmer experience that flashing
smaller images (with the suggested bottom alignment) bricks their
systems by default?