OMAP3 L2/outer cache enabled in kernel (after being disabled by uBoot)?

[Shilimkar, Santosh]

+ linux-arm, Russell and Catalin

On Mon, Jan 16, 2012 at 11:03 AM, Joe Woodward <jw at terrafix.co.uk> wrote:
> The latest uBoot release (2011.12) disables the L2/outer cache during boot on OMAP boards.
>
> uBoot commit: "armv7: disable L2 cache in cleanup_before_linux()" on 6th Dec 2011 by Aneesh V adds the following to
> uBootSources/arch/arm/cpu/armv7/cpu.c:cleanup_before_linux():
>  ...
>  v7_out_cache_disable();
>
> The commit message implies this change was to make booting reliable on OMAP4 by disabling L2 cache before jumping to Linux. Sadly
> this commit also affects OMAP3-based boards...
>
> Since switching to uBoot 2011.12 I'm seeing about half the performance on my GUSMTIX Overo (OMAP3530).
>
> In the kernel sources there seem to be OMAP4 specific functions for re-enabling the L2 cache (omap4-common.c:omap_l2_cache_init()),
> but none for OMAP3.
>
> So my question is... do we expect that Linux should be re-enabling the L2/outer cache during boot after uBoot has disabled it on OMAP3?
>
Yes. Kernel already does enabled L2 on A8 CPU's but OMAP3 needs a
secure call and then the patching becomes
that much difficult.

We need some kind of generic hook in proc*_setup() function where in
such secure bits can be turned ON.

Regards
Santosh