[U-Boot] [PATCH] ARM: tegra: only enable SCU on Tegra20

[Stephen Warren]

On 05/23/2013 04:26 PM, Stephen Warren wrote:
> From: Tom Warren <twarren at nvidia.com>
> 
> The non-SPL build of U-Boot on Tegra only runs on a single CPU, and
> hence there is no need to enable the SCU when running U-Boot. If an
> SMP OS is booted, and it needs the SCU enabled, it will enable the SCU
> itself. U-Boot doing so is redundant.
> 
> The one exception is Tegra20, where an enabled SCU is required for some
> aspects of PCIe to work correctly.
> 
> Some Tegra SoCs contain CPUs without a software-controlled SCU. In this
> case, attempting to turn it on actively causes problems. This is the case
> for Tegra114. For example, when running Linux, the first (or at least
> some very early) user-space process will trigger the following kernel
> message:
> 
> Unhandled fault: imprecise external abort (0x406) at 0x00000000
> 
> This is typically accompanied by that process receving a fatal signal,
> and exiting. Since this process is usually pid 1, this causes total
> system boot failure.

Tom, is this patch OK? It's a rather critical bug-fix for Tegra114, so
I'd like to make sure it gets into the upcoming release. Thanks.