Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 6 Apr 2023 12:08:20 +0800
From:   Shawn Guo <shawn.guo@linaro.org>
To:     Konrad Dybcio <konrad.dybcio@linaro.org>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Subject: Re: [PATCH v2 2/2] irqchip: irq-qcom-mpm: Support passing a slice of
 SRAM as reg space
Message-ID: <20230406040820.GB111746@dragon>
References: <20230328-topic-msgram_mpm-v2-0-e24a48e57f0d@linaro.org>
 <20230328-topic-msgram_mpm-v2-2-e24a48e57f0d@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230328-topic-msgram_mpm-v2-2-e24a48e57f0d@linaro.org>
Precedence: bulk

On Wed, Apr 05, 2023 at 12:48:35PM +0200, Konrad Dybcio wrote:
> The MPM hardware is accessible to us from the ARM CPUs through a shared
> memory region (RPM MSG RAM) that's also concurrently accessed by other
> kinds of cores on the system (like modem, ADSP etc.). Modeling this
> relation in a (somewhat) sane manner in the device tree basically
> requires us to either present the MPM as a child of said memory region
> (which makes little sense, as a mapped memory carveout is not a bus),
> define nodes which bleed their register spaces into one another, or
> passing their slice of the MSG RAM through some kind of a property.
> 
> Go with the third option and add a way to map a region passed through
> the "qcom,rpm-msg-ram" property as our register space.
> 
> The current way of using 'reg' is preserved for ABI reasons.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Acked-by: Shawn Guo <shawn.guo@linaro.org>