[Arm-dev] Why RPi3 under Arm32 rather than AArch64?

[Gordan Bobic]

Things required to "support" Pi3 aarch64 that aren't already in place in
core CentOS (or at least I haven't managed to find them):

1) Pi3 firmware blobs
Trivially downloadable from
https://github.com/raspberrypi/firmware/tree/master/boot

2) UEFI bootloader
There are two options, u-boot and Tianocore.
My current Pi3 aarch64 image works with u-boot that I grabbed from the
Fedora 26 image.
I'm currently trying to get it working with Tianocore from here:
https://github.com/andreiw/RaspberryPiPkg
I _almost_ have it working (gets as far as booting grub, but grub then
doesn't manage to boot up the kernel, almost certainly a dtb issue
somewhere).

3) Kernel
I keep my own mainline kernel build for aarch64, loosely based on, IIRC,
4.5.x that shipped with CentOS aarch64, but with some modifications. I have
a build that works on both my X-Gene and the Pi3. You can find it here:
http://ftp.redsleeve.org/pub/misc/kernel/aarch64/RPMS/
(Note: I only included Pi 3 SoC configuration as of 4.9.73).

So it's not exactly an insurmountable problem, it's just a case off
dropping a tarball of 5-6 files onto the /boot/efi FAT partition, having
the appropriate kernel installed in the image, and it should "just work".
I can have a working image with u-boot EFI as soon as I find half an hour
to spare.
The one with Tianocore EFI will take a little longer.



On Thu, Jan 4, 2018 at 9:55 PM, Fabian Arrotin <arrfab at centos.org> wrote:

> On 04/01/18 19:26, Christopher Ursich wrote:
> > Hi, all.  First-timer here.
> >
> > I am setting up a new Raspberry Pi 3.  When I review the AltArch pages,
> > I see that most of the RPi3 coverage is categorized under Arm32,
> including
> >
> >   https://wiki.centos.org/SpecialInterestGroup/AltArch/
> Arm32/RaspberryPi3
>
> Because we targeted armhfp even for the Pi3 initially, as even the Pi
> Foundation had no plan to provide/build at the beginning aarch64
> kernel/code for the pi3
> TBH (my own opinion) it doesn't even really make sense to use aarch64
> code on the pi3 itself with such low specs .. only benefit is probably
> that epel exists for aarch64 vs armhfp and also same tree if you want to
> deploy to "real" aarch64 nodes in Datacenter ...
>
> Now, I'll let Jim (the aarch64 maintainer) explain his plans for aarch64
> tree for pi3, but at this stage of meltdown and spectre, I guess we all
> have other urgent things to do too :-)
>
> --
> Fabian Arrotin
> The CentOS Project | https://www.centos.org
> gpg key: 56BEC54E | twitter: @arrfab
>
>
> _______________________________________________
> Arm-dev mailing list
> Arm-dev at centos.org
> https://lists.centos.org/mailman/listinfo/arm-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.centos.org/pipermail/arm-dev/attachments/20180104/45821a88/attachment.html>