[PATCH 2/3] arm64: Add big.LITTLE switcher stub

Sudeep Holla sudeep.holla at arm.com
Fri May 9 10:05:56 PDT 2014

Hi Mark,

On 09/05/14 17:40, Mark Brown wrote:
> From: Mark Brown <broonie at linaro.org>
> The big.LITTLE cpufreq driver is useful on arm64 big.LITTLE systems even
> without IKS support since it implements support for clusters with shared
> clocks (a common big.LITTLE configuration). In order to allow it to be
> built provide the non-IKS stubs for arm64, enabling cpufreq with all the
> cores available.

I am in process of using this driver for ARM64 and hit the same issue.
I don't like this approach at all. I too did similar changes/hacks which are
good for quick testing but not for upstream.

I would like to move all the switcher code out of the driver as extension.
Also the core driver should be made to work with any multi-clsuter platform not
just big-little(bL). bL is one of them and bL switcher support should an
extension of it.

The main reason for this is I see some non-bL multi-cluster platform support
getting added, this driver should ideally support that.

> It may make sense to make an asm-generic version of these stubs instead but
> given that there's only likely to be these two architectures using the code
> and asm-generic stubs also need per architecture updates it's probably more
> trouble than it's worth.

I would not take this approach too. As mentioned above if we can resolve it in
that way we may not require this.


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