[PATCH] ARM64: juno: add NOR flash to device tree
linus.walleij at linaro.org
Tue Oct 27 04:59:19 PDT 2015
On Wed, Oct 21, 2015 at 1:18 PM, Ryan Harkin <ryan.harkin at linaro.org> wrote:
> There is no global TOC placed in NOR or elsewhere.
> Each image stored in NOR flash contains a "footer" at the end of the
> last sector of the image. This footer describes the image, including
> it's image "name".
> To find all of the images in NOR flash, the AFS code has to scan for
> the footer's signature at the end of every sector in flash. The v1
> footer is the last 4 bytes of the sector, the v2 footer is the last 8
> bytes. Juno uses v2 footers.
Yeah it's made like this to facilitate execute-in-place. You can't
mess with the data in the beginning of the image if you're going
to be able to execute it right off.
Not that I know if execute-in-place for ARM64 was ever an option,
it can be done I guess... anyways this is a legacy format for
all ARM reference designs.
As mentioned it the other mail, if we agree on a name for the
read-only bootloader/EFI data partition, it can easily be made into
as a readonly thing.
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