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Subject: Re: [PATCH v2] firmware: qcom_scm: Only compile legacy calls on ARM
From:   Stephen Boyd <swboyd@chromium.org>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Elliot Berman <eberman@codeaurora.org>,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        Brian Masney <masneyb@onstation.org>,
        Jeffrey Hugo <jhugo@codeaurora.org>,
        Douglas Anderson <dianders@chromium.org>
To:     Stephan Gerhold <stephan@gerhold.net>
Date:   Thu, 08 Apr 2021 14:18:25 -0700
Message-ID: <161791670545.3790633.14772376161713976241@swboyd.mtv.corp.google.com>
User-Agent: alot/0.9.1
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Quoting Stephan Gerhold (2021-04-08 00:19:44)
> Personally, I think it would be best to introduce a new, SMC64 only
> compatible (e.g. "qcom,scm-64" like I mentioned). Then you can skip the
> detection check for the boards that opt-in by adding the compatible.
> You can then use it on all newer boards/SoCs/firmwares where you know
> exactly that there is SMC64.
>=20
> I would just like to avoid breaking any existing boards where we don't
> know exactly if they have SMC32 or SMC64.

Ok that's fair.

> >=20
> > Heh, it tried to ensure we use the right calling convention but broke
> > things in the process, because the way of detecting the convention isn't
> > always there. I wouldn't be surprised if this comes up again for other
> > boards that use TF-A.
>=20
> Ah okay, this sounds like a better reason than just trying to avoid the
> "overhead" of the detection step. :) I still think it should work if you
> just start marking all newer boards/SoCs/... as "qcom,scm-64" or
> something like that, right?

Sure. I can cook up a set of patches for this.