[PATCH 1/2] ARM: tegra: add CPU errata WARs to Tegra reset handler

Stephen Warren swarren at wwwdotorg.org
Wed Mar 6 15:29:51 EST 2013


On 03/04/2013 05:05 PM, Stephen Warren wrote:
> The CPU cores in Tegra contain some errata. Workarounds must be applied
> for these every time a CPU boots. Implement those workarounds directly
> in the Tegra-specific CPU reset vector.
> 
> Many of these workarounds duplicate code in the core ARM kernel.
> 
> However, the core ARM kernel cannot enable those workarounds when
> building a multi-platform kernel, since they require writing to secure-
> only registers, and a multi-platform kernel often does not run in secure
> mode, and also cannot generically/architecturally detect whether it is
> running in secure mode, and hence cannot either unconditionally or
> conditionally apply these workarounds.
> 
> Instead, the workarounds must be applied in architecture-specific reset
> code, which is able to have more direct knowledge of the secure/normal
> state. On Tegra, we will be able to detect this using a non-architected
> register in the future, although we currently assume the kernel runs only
> in secure mode. Other SoCs may never run the kernel in secure mode, and
> hence always rely on a secure monitor to enable the workarounds, and
> hence never implement them in the kernel.

I have applied this series to Tegra's for-3.10/fixes branch.




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