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ARM: Meson6: enable SMP

Maxime Ripard linux-arm-kernel 1 version New

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  1. v1 Latest0 of 3 patches 0 repliesNew

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Cover letter [PATCH 0/3] ARM: Meson6: enable SMP
Quoted 37 lines · Arnd Bergmann
Quoted 27 lines · On Thursday 02 October 2014 16:54:26 Maxime Ripard wrote:
Quoted 26 lines · Arnd Bergmann
Quoted 12 lines · On Tuesday 30 September 2014 22:45:38 Carlo Caione wrote:
Quoted 11 lines · Arnd Bergmann
Quoted 6 lines · On Tuesday 30 September 2014 10:46:46 Carlo Caione wrote:
Quoted 2 lines · Carlo Caione

Amlogic Meson6 is a dual-core Cortex-A9. This patchset adds all the necessary pieces to boot the secondary CPU.

Sorry for the double sending.
Forgot to CC LAKML.

Looks good to me in principle, but I wonder about the CPU enable method. Are you able to implement PSCI in u-boot like it was done for allwinner?

Quoted 8 lines
Quoted 2 lines

This is mostly a question of whether the system comes up in secure mode or non-secure mode.

I would be able if I had the u-boot source code or the possibility to flash the board I'm using. Unfortunately at this moment I don't have either. Probably in the near future I'll be able to implement PSCI in u-boot since Amlogic is kindly starting to provide documentation but now this is the best I can do.

Ok, I see. Let's give Amlogic some more time then. I think it's better to merge other parts of the platform first when we can reasonably assume that we don't have to change the binding any more.

Quoted 8 lines
Quoted 3 lines

It would be a shame to merge this now and then make it obsolete by implementing PSCI but still having to carry around the original code for compatibility reasons.

More likely, PSCI is not going to be supported by the bootloaders of the devices already in the wild, so we still have to provide them an option. And even when it will, you'll still have to support both the devices with the old bootloaders, and the one with the new.

Quoted 4 lines

It depends on how common the old boot loaders are, and whether it's possible to upgrade them. If we can get to the point where you can boot a kernel with a single CPU and have an easy way to update the boot loader, we don't need to support it.

I thought I heard Olof at some point ranting about this kind of requirements, but ok :)

Still, holding off until something that hypothetical happens looks a bit odd, doesn't it?

Maxime

Signature · 10 lines
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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