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From: Bartosz Golaszewski <brgl@bgdev.pl>
Date: Mon, 25 Mar 2024 11:08:00 +0100
Message-ID: <CAMRc=Mce+PbCYdBOrWT=aFBUj+c=SU54z0=CJqr4HsrCgzKoEA@mail.gmail.com>
Subject: Re: [PATCH v9 00/13] firmware: qcom: qseecom: convert to using the TZ allocator
To: Andy Gross <agross@kernel.org>, Bjorn Andersson <andersson@kernel.org>, 
	Konrad Dybcio <konrad.dybcio@linaro.org>, Elliot Berman <quic_eberman@quicinc.com>, 
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, 
	Guru Das Srinagesh <quic_gurus@quicinc.com>, Andrew Halaney <ahalaney@redhat.com>, 
	Maximilian Luz <luzmaximilian@gmail.com>, Alex Elder <elder@linaro.org>, 
	Srini Kandagatla <srinivas.kandagatla@linaro.org>, Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-arm-kernel@lists.infradead.org, kernel@quicinc.com, 
	Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
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On Mon, Mar 25, 2024 at 11:04=E2=80=AFAM Bartosz Golaszewski <brgl@bgdev.pl=
> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> SCM calls that take memory buffers as arguments require that they be
> page-aligned, physically continuous and non-cachable. The same
> requirements apply to the buffer used to pass additional arguments to SCM
> calls that take more than 4.
>
> To that end drivers typically use dma_alloc_coherent() to allocate memory
> of suitable format which is slow and inefficient space-wise.
>
> SHM Bridge is a safety mechanism that - once enabled - will only allow
> passing buffers to the TrustZone that have been explicitly marked as
> shared. It improves the overall system safety with SCM calls and is
> required by the upcoming scminvoke functionality.
>
> The end goal of this series is to enable SHM bridge support for those
> architectures that support it but to that end we first need to unify the
> way memory for SCM calls is allocated. This in itself is beneficial as
> the current approach of using dma_alloc_coherent() in most places is quit=
e
> slow.
>
> First let's add a new TZ Memory allocator that allows users to create
> dynamic memory pools of format suitable for sharing with the TrustZone.
> Make it ready for implementing multiple build-time modes.
>
> Convert all relevant drivers to using it. Add separate pools for SCM core
> and for qseecom.
>
> Finally add support for SHM bridge and make it the default mode of
> operation with the generic allocator as fallback for the platforms that
> don't support SHM bridge.
>
> Tested on db410c, RB5, sm8550-qrd. Previous iteration tested also on
> sa8775p-ride and lenovo X13s (please do retest on those platforms if you
> can).
>

The Subject should have been "firmware: qcom: implement support for
and enable SHM bridge", sorry for the mixup.

Bartosz