On 13/07/17 08:33, Bin Chen wrote:
Hi Tom,
Thanks for the review.
On 13 July 2017 at 04:25, Tom Rini <tr...@konsulko.com
<mailto:tr...@konsulko.com>> wrote:
On Tue, Jul 11, 2017 at 03:56:04PM +1000, Bin Chen wrote:
> It's my understanding that we are supposed to use booti, instead of bootm,
> for arm64 image. But booti lacks of android image support. Bootm has
> the andriod image support but lack of the arm64 image handling.
>
> So, what is suppose the right way of booting an android arm64 image?
> or, should we create a separate command?
>
> This patch is an invitation for that discussion.
>
> It *hacked* the booti command and it aslo assume the dtb is in the second
area
> of android boot image. It also has other belives like u-boot should be
> in control of where to put the kernnel/ramdisk/dtb images so it ignores
> the value specified in the android images.
>
> Signed-off-by: Bin Chen <bin.c...@linaro.org <mailto:bin.c...@linaro.org>>
So, booti is very much for the "Image" format described in the Linux
kernel in Documentation/arm64/booting.txt. One can (and people have)
used bootm on aarch64 for "uImage" style kernels and FIT kernels, and I
would see being able to boot an aarch64 Android image with bootm as the
way to go forward.
Are you suggesting that we should use bootm path, instead of booti?
I have two questions regarding this:
1. currently arm64 kernel don't have a uImage kernel target. And I'm not
sure
if adding that will be something that is wanted and/or sensible.
All arm64 kernels are multi-platform (even if for some minimized builds
only drivers for one platform are actually enabled). That means a uImage
kernel target is problematic because the kernel build system does not
know its eventual physical load address. On arm64 that is entirely
delegated to the bootloader.
That doesn't mean uImage can never be used; just that the kernel build
system has no business authoring one.
2. bootm path doesn't have the logic that is currently in the booti,
such as the
kernel relocation.
Also, one other question raised during internal discussion was why the
booti
was created in the first place, if we could have had that implemented in
the
bootm path.
The analogy would be that we use bootm for Android
on arm not bootz. Thanks!
--
Tom
--
Regards,
Bin
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