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Re: Flash V2 with 2 flash chips on board !
On Tue, Nov 22, 2005 at 09:18:28AM +0100, Manfred Gruber wrote:
> Hi !
>
> thanks a lot for your answer.
>
> Am Sonntag, 20. November 2005 23:14 schrieben Sie:
> > Setting up the MMU tables is the responsibility of the platform HAL.
> > No other package will know exactly what chips are present on the
> > target hardware. The first flash chip can always be mapped to an
> > appropriate virtual address. For the second one, you could map it into
> > the virtual address space irrespective of whether or not it is
> > present. Alternatively you can do run-time detection and only map it
> > if present. If the first flash chip is variable size and the second
> > must appear contiguous then run-time mapping is unavoidable.
>
> So, as I understand correct,for example I have two flash chips on my device
> 2x32MB. The first one is physical on 0xf0000000 and the second one is on
> 0x10000000. I have to map them to a virtual address like that:
>
> first chip virtual 0xf0000000
> 0xf2000000 -- first 32mb
> second chip 0xf2000000
> 0xf4000000 -- second 32mb
>
> would this be correct ?
>
> the second chip only would be maped if it is present, and my second
> CYG_FLASH_DRIVER() function would so a custom init function to detect if a
> chip is on 0xf2000000?
>
> will this chips then appear as one flash device in redboot? so that
> later linux will detect the redboot partitions, because of concate
> them in linux ?
To Redboot they will still be two flash devices. But redboot will be
happy to store images in both and it should also be happy to have an
image which spans from one device to the second device. However i
don't think i tested this.
Are you using a jffs2 filesystem? I don't know how jffs2 will handle
spanning two devices, especially if the block sizes are different
between the two devices. This is something you will have to test.
Andrew
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