Re: Only 1 CPU on Jetson TX1

[Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On Mon, Mar 27, 2017 at 09:39:43AM -0600, Stephen Warren wrote:
> On 03/26/2017 04:49 PM, Martin Michlmayr wrote:
> > * Mikko Perttunen <cyndis-/1wQRMveznE@public.gmane.org> [2017-03-25 10:32]:
> > > It appears you need to have
> > > 
> > >   fdt_copy_node_names=/cpus:/psci
> > >   fdt_copy_src_addr=0x83080000
> > > 
> > > in your U-Boot configuration. This is documented somewhere in the middle of
> > > http://elinux.org/Jetson/TX1_Upstream_Kernel.
> > 
> > I can confirm that this works with u-boot from L4T R24.2.1.
> > 
> > However, it doesn't work with mainling u-boot (grepping for fdt_copy_
> > doesn't show anything in the source code).
> > 
> > Does anyone know how to get all 4 CPUs working with mainline u-boot?
> 
> Thierry, Jon, do you know?
> 
> The "fdt_copy" feature of U-Boot isn't upstreamed since I thought it was
> only required to boot the L4T kernel, not mainline. We're also reworking L4T
> so this feature won't be needed there either, so I don't expect to upstream
> "fdt_copy".

I vaguely remember that we had discussed this a while ago and I think we
decided that we should hardcode the /psci and /cpus nodes within the DTS
file on the basis that firmware would be considered part of the hardware
as far as the device tree description of it is concerned.

Technically, hard-coding isn't quite correct because someone might end
up not using the firmware that ships with L4T and therefore not have a
working PSCI implementation, but I think it's fairly unlikely that
someone will do that.

Thierry

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