[LinuxBIOS] Question about Config file

ccases at navista.fr ccases at navista.fr
Wed Mar 21 10:14:16 CET 2007

>  > I use the fallback and the normal mode, if my chip has a size 256*1024,
>> what  size of FALLBACK_SIZE and ROM_IMAGE_SIZE I can choose, I have some
>> difficulty to define the role of the ROM_IMAGE_SIZE, the ROM_SIZE define
>> the  size of the chip, the FALLBACK_SIZE define the size of the fallback
>> mode, but the ROM_IMAGE_SIZE ??? I don't understand the goal of
>> ROM_IMAGE_SIZE, if you have an better explaination that on the Web site,
>> I
>> would appreciate much.
> Just to make sure first, after changing anything in the config'lb or
> options.lb files, you have to re-run ./buildtarget to recreate the make
> files with the new values.
> If I understand it right, this is pretty much how it works, and some
> reasonable values for a 256k flash part:
> ROM_IMAGE_SIZE determines the amount of space for lb's fallback image to
> take up, 64kb (64*1024, or 0x10000). The minimum size of this is
> dependent on the code, I don't know how you'd find it out other than
> trial-and-error, but there must be a way.
> FALLBACK_SIZE determines the space for the fallback lb image + the
> payload for the "fallback.rom", 128kb (128*1024, or 0x20000). This means
> 64kb for lb+64kb for the payload. This at minimum needs to be
> (obviously) the size of your built code + the size of your payload.
> Also, make sure your Options.lb contains "default HAVE_FALLBACK_BOOT=1".
> ROM_IMAGE_SIZE again determines the size for the normal image's code, 64kb
> ROM_SIZE determines the size of the whole chip, 256kb. LB then computes
> ROM_SIZE - FALLBACK_SIZE to get the size for the "normal.rom", which is
> the normal lb code + the payload again.
> At the end, lb merges the fallback.rom(128k) and normal.rom (128k) to
> give you linuxbios.rom (256k).
> There are some other options, like PAYLOAD_SIZE and ROM_SECTION_SIZE,
> these should be computed by your src/../Config.lb based on the other
> values. If you still have problems, grab the config.lb's and options.lb
> from the asus p2b and use the values in those, they build a 256k flash
> part for me just fine.
> -Corey

Thank's for all of your explaination, now have a better vision of the
things, thanks again ;)



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