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From:   Doug Anderson <dianders@chromium.org>
Date:   Wed, 21 Jun 2023 09:56:15 -0700
Message-ID: <CAD=FV=WqirzpMwq8wto2B9cDGVf5JfirAQRargKWcZLpFhXCVA@mail.gmail.com>
Subject: Re: [PATCH v2 1/4] dt-bindings: firmware: qcom,scm: Document that SCM
 can be dma-coherent
To:     andersson@kernel.org, SoC Team <soc@kernel.org>
Cc:     amit.pundir@linaro.org, Will Deacon <will@kernel.org>,
        sumit.semwal@linaro.org, linux-arm-msm@vger.kernel.org,
        konrad.dybcio@somainline.org, linux-arm-kernel@lists.infradead.org,
        Stephan Gerhold <stephan@gerhold.net>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        Nikita Travkin <nikita@trvn.ru>,
        Stephen Boyd <swboyd@chromium.org>,
        Sibi Sankar <quic_sibis@quicinc.com>,
        Andy Gross <agross@kernel.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Das Srinagesh <quic_gurus@quicinc.com>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Robert Marko <robimarko@gmail.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Bjorn,

On Fri, Jun 16, 2023 at 8:18=E2=80=AFAM Douglas Anderson <dianders@chromium=
.org> wrote:
>
> Trogdor devices use firmware backed by TF-A instead of Qualcomm's
> normal TZ. On TF-A we end up mapping memory as cacheable. Specifically,
> you can see in Trogdor's TF-A code [1] in qti_sip_mem_assign() that we
> call qti_mmap_add_dynamic_region() with MT_RO_DATA. This translates
> down to MT_MEMORY instead of MT_NON_CACHEABLE or MT_DEVICE.
>
> Let's allow devices like trogdor to be described properly by allowing
> "dma-coherent" in the SCM node.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
> Changes in v2:
> - Bindings change new for v2.
>
>  Documentation/devicetree/bindings/firmware/qcom,scm.yaml | 2 ++
>  1 file changed, 2 insertions(+)

Without this series v6.4 will have a regression where WiFi / LTE won't
work at all on trogdor devices. Any chance you can send up a "Fixes"
pull request with the 4 patches in it? ...or I could try to convince
someone on the SoC tree to land them directly?

Thanks!

-Doug