Re: [RFC] Kbuild support for ARM FIT images

Pavel Machek
2013-03-18T18:05:09Z

On Mon 2013-03-18 17:57:46, Russell King - ARM Linux wrote:
> On Mon, Mar 18, 2013 at 06:49:32PM +0100, Pavel Machek wrote:
> > What I wanted to say is that kernel build traditionaly produced
> > something useful, something bootloader can actually boot. Currently,
> > make uImage produces u-boot image. Please keep that capability.
>
> Unfortunately, there is a fundamental problem with uImage. It encodes
> the load address, and that is utterly incompatible with the goal of
> having a kernel image which boots on multiple platforms.
>
> uImage isn't going anywhere for the time being, but you will find
> that:
>
> a) recent kernels will just wrap the zImage without a DTB, so
> appended DTBs can't be used with it
> b) it won't work with MULTIPLATFORM-enabled kernels, unless you
> provide make with a LOADADDR= argument to tell it where the
> uImage is to be loaded - which is platform specific.
>
> (b) fundamentally can't be solved in kbuild. If you want to use
> uImage with multiple platforms from the same zImage, then you need
> to generate multiple uImage files with different load addresses.
> That's purely - and solely - down to the dysfunctional uImage format.

I know. uImage is not perfect. But solution should be "adopt a better
format" (ARM FIT?), not "drop support for making useful images
altogether" as Olof proposed before.
Pavel
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