[RFC PATCH v2 00/13] ARM: DT cpu bindings updates

Arnd Bergmann arnd at arndb.de
Mon Apr 22 15:18:41 EDT 2013


On Monday 22 April 2013, Lorenzo Pieralisi wrote:
> > Thoughts? I notice Catalin has some patches queued for arm64 which
> > unconditionally use of_property_read_u64, but I have a patch to honour the
> > #address-cells property instead.
> 
> Basically you want me to rule out passing a dtb with cpus node having
> #address-cells == 2 to a 32-bit kernel, correct ? Or put it another way:
> 
> - a 32-bit kernel must always get passed a dtb with cpus node
>   #address-cells == 1. 

Why that? For other registers, we allow leading zeroes. This is
already required for MMIO registers on LPAE capable machines.

>   If the system is ARMv8 with CPUs having
>   MPIDR_EL1[63:32] != 0x0, well, running 32-bit kernel on it is not
>   the safest thing to do anyway.

I would assume the hypervisor to provide a virtual MPIDR_EL1 for
a 32 bit kernel in that case.

	Arnd



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