Subject: Re: Proposed: Patch to fix boot on PA6T

From: Benjamin Herrenschmidt <[email-masked]>
Date: Mon, 27 Jun 2016 08:50:01 +1000

On Sun, 2016-06-26 at 18:42 +0100, Darren Stevens wrote:
> 
>     commit d6a9996e84ac4beb7713e9485f4563e100a9b03e
>     powerpc/mm: vmalloc abstraction in preparation for radix
> 
>     This commit introduced variables for some linux kernel addresses that had
> before been constants, unfortunately this stopped PaSemi PA6T systems(*) from
> booting as they call ioremap to map SoC registers before the mmu is initialised. The
> attached patch adds a hard-coded init of pci_io_base to the pas_init_early()
> function which which allows the kernel to boot normally.

Tell me more, when is that mapping done ? I'm changing things so that
platform probe is called much later so that might have an impact.

What consumes pci_io_base before it's been initialized ?

>     The value will be harmlessly set again once pci starts up.
> 
>     (*) At the moment this has only been tested on an AmigaOneX1000, but I
> expect PaSemi
>     reference systems to have been affected in the same way.