[Nix-dev] Raspberry-Pi NixOS

[Rok Garbas]

sry i only have questions in this email :)


- how would we speed up building? so that other can get binaries at
least for the "base" of the nixos.

- would we just hook up rpi's into hydra? can we hook this to existing
hydra.nixos.org or we would have to come with our own hydra.

- can we also collect this knowledge in some kind of manual, be it
part of nixos manual or completely separated.

- i'm still waiting for my rpi3 to arrive, but where can i help until
then? i'd love to have proper support for rpi in nixpkgs.



On Wed, Jul 20, 2016 at 12:05 AM, Lluís Batlle i Rossell
<viric at viric.name> wrote:
> On Tue, Jul 19, 2016 at 11:53:59PM +0200, Tomas Hlavaty wrote:
>> Lluís Batlle i Rossell <viric at viric.name> writes:
>> > The device tree blob should be built by the kernel, like with pi and pi2,
>> > isn't it?
>>
>> This is the kernel which works for me and is taken from
>> raspberry-firmware/boot:
>>
>> Linux version 4.4.13-v7+ (dc4 at dc4-XPS13-9333) (gcc version 4.9.3
>> (crosstool-NG crosstool-ng-1.22.0-88-g8460611) ) #894 SMP Mon Jun 13
>> 13:13:27 BST 2016
>>
>> and the corresponding device tree is bcm2710-rpi-3-b.dtb.
>>
>> This looks like the same kernel version in
>> pkgs/os-specific/linux/kernel/linux-rpi.nix (modDirVersion = "4.4.13";
>> tag = "1.20160620-1")
>>
>> Are you saying that this is not good enough?
>>
>> What works: If I copy files from raspberry-firmware/boot to /boot, rpi3
>> starts fine.  These are the files I have in /boot:
>>
>> $ ls -al /boot
>> -rwxr-xr-x  1 root root   13221 Jun 18 22:31 bcm2708-rpi-b.dtb
>> -rwxr-xr-x  1 root root   13484 Jun 18 22:31 bcm2708-rpi-b-plus.dtb
>> -rwxr-xr-x  1 root root   13257 Jun 18 22:31 bcm2708-rpi-cm.dtb
>> -rwxr-xr-x  1 root root   14567 Jun 18 22:31 bcm2709-rpi-2-b.dtb
>> -rwxr-xr-x  1 root root   15237 Jun 18 22:31 bcm2710-rpi-3-b.dtb
>> -rwxr-xr-x  1 root root   17932 Jun 18 22:31 bootcode.bin
>> -rwxr-xr-x  1 root root     165 Jul 19 22:46 cmdline.txt
>> -rwxr-xr-x  1 root root    1369 Jan 11  2016 config.txt
>> -rwxr-xr-x  1 root root    2504 Jun 23 20:42 fixup_cd.dat
>> -rwxr-xr-x  1 root root    6482 Jun 23 20:42 fixup.dat
>> -rwxr-xr-x  1 root root    9717 Jun 23 20:42 fixup_db.dat
>> -rwxr-xr-x  1 root root    9717 Jun 23 20:42 fixup_x.dat
>> -rwxr-xr-x  1 root root 4224232 Jun 18 22:31 kernel7.img
>> drwxr-xr-x  2 root root    8192 Jun 18 22:31 overlays
>> -rwxr-xr-x  1 root root  617432 Jun 23 20:42 start_cd.elf
>> -rwxr-xr-x  1 root root 4926264 Jun 23 20:42 start_db.elf
>> -rwxr-xr-x  1 root root 2746552 Jun 23 20:42 start.elf
>> -rwxr-xr-x  1 root root 3877720 Jun 23 20:42 start_x.elf
>>
>> I don't see, why raspberrypi/builder.sh creates defaultgeneration,
>> initrd and nixos-init files in /boot.  It actually seems to me, that
>> initrd should not be there at all for the boot to work.
>>
>> raspberrypi/builder.sh doesn't create fixup_x.dat, which is in the list
>> above; but I haven't tried booting without it.
>>
>> Although pkgs/os-specific/linux/kernel/linux-rpi.nix copies DTB files,
>> it renames them to something that looks wrong and also it does not copy
>> them to /boot at all:
>>
>>     # I am not sure if all of these are correct...
>>     copyDTB bcm2708-rpi-b.dtb bcm2835-rpi-a.dtb
>>     copyDTB bcm2708-rpi-b.dtb bcm2835-rpi-b.dtb
>>     copyDTB bcm2708-rpi-b.dtb bcm2835-rpi-b-rev2.dtb
>>     copyDTB bcm2708-rpi-b-plus.dtb bcm2835-rpi-a-plus.dtb
>>     copyDTB bcm2708-rpi-b-plus.dtb bcm2835-rpi-b-plus.dtb
>>     copyDTB bcm2708-rpi-b-plus.dtb bcm2835-rpi-zero.dtb
>>     copyDTB bcm2708-rpi-cm.dtb bcm2835-rpi-cm.dtb
>>     copyDTB bcm2709-rpi-2-b.dtb bcm2836-rpi-2-b.dtb
>>     copyDTB bcm2710-rpi-3-b.dtb bcm2837-rpi-3-b.dtb
>>
>> I looks like the files in raspberry-firmware/boot should work on any rpi
>> version so we should probably immitate that somehow in nixos and at
>> least get it to work out of the box even if we just take the precompiled
>> files from raspberrypi-firmware/boot and improve that later.
>
> I don't remember any of the details. I'm using it in rpi2 just fine. I
> could forget some file, and I may have written code that is fit just for a
> very specific kernel version. Maybe it has all changed in 4.4.
>
> The relevant detail that I remember is that the kernel recipe is told to
> build the DTB, so I think that you should not need any dtb from the
> firmwarefiles/boot.
>
> Regards,
> Lluís.
>
> --
> (Escriu-me xifrat si saps PGP / Write ciphered if you know PGP)
> PGP key D4831A8A - https://emailselfdefense.fsf.org/
> _______________________________________________
> nix-dev mailing list
> nix-dev at lists.science.uu.nl
> http://lists.science.uu.nl/mailman/listinfo/nix-dev



-- 
Rok Garbas
https://garbas.si