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;
Message-ID: <15f48b06-a6be-1295-5deb-d3594bce6699@linaro.org>
Date:   Wed, 12 Apr 2023 18:53:12 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.1
Subject: Re: [PATCH v2 1/2] dt-bindings: interrupt-controller: mpm: Pass MSG
 RAM slice through phandle
Content-Language: en-US
To:     Konrad Dybcio <konrad.dybcio@linaro.org>,
        Stephan Gerhold <stephan@gerhold.net>
Cc:     Rob Herring <robh@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andy Gross <agross@kernel.org>, linux-kernel@vger.kernel.org,
        Shawn Guo <shawn.guo@linaro.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Marc Zyngier <maz@kernel.org>, linux-arm-msm@vger.kernel.org,
        devicetree@vger.kernel.org
References: <20230328-topic-msgram_mpm-v2-0-e24a48e57f0d@linaro.org>
 <20230328-topic-msgram_mpm-v2-1-e24a48e57f0d@linaro.org>
 <168069726278.2356075.14351594478003012447.robh@kernel.org>
 <20230405134727.GA2461305-robh@kernel.org>
 <1e6e2590-ac78-400b-35ce-321d5e52f385@linaro.org>
 <9df12111-ec84-c4f7-fbcb-bccaef91b048@linaro.org>
 <3ce9b5ec-8b02-537a-c663-c849e80cab66@linaro.org>
 <ZDAAToSzNLVo6le8@gerhold.net>
 <198523f5-d06f-15cd-af6c-f391c02bcaa9@linaro.org>
 <1f8fc036-380b-0a42-bb29-a3e275ed6a33@linaro.org>
 <2e648a97-083e-8ee2-1695-4af299bb222a@linaro.org>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <2e648a97-083e-8ee2-1695-4af299bb222a@linaro.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 12/04/2023 14:09, Konrad Dybcio wrote:
> 
> 
> On 12.04.2023 13:55, Krzysztof Kozlowski wrote:
>> On 12/04/2023 13:47, Konrad Dybcio wrote:
>>>> For unrelated reasons I actually have some patches for this, that switch
>>>> the /smd top-level node to a "remoteproc-like" node dedicated to the
>>>> RPM, similar to how WCNSS/ADSP/Modem/etc are represented. I need this to
>>>> add additional (optional) properties like "resets" and "iommus" for the
>>>> RPM, but it would allow adding arbitrary subnodes as well:
>>>>
>>>> https://github.com/msm8916-mainline/linux/commit/35231ac28703805daa8220f1233847c7df34589e
>>>>
>>>> I could finish those up and post them if that would help...
>>> Krzysztof, what do you think?
>>
>> I don't know what is there in MSM8916 and how it should be represented.
> Similarly to other Qualcomm SoCs, MSM8916 has a RPM (Cortex-M3) core,
> which communicates over the SMD protocol (or G-LINK on >=8996).
> 
> The Qualcomm firmware loads the RPM fw blob and sets it up early in
> the boot process, but msm8916-mainline folks managed to get TF-A
> going and due to it being less.. invasive.. than the Qualcomm TZ,
> RPM needs a bit more handling to be accessible.
> 
> The M3 core is wired up through the CNoC bus and we communicate
> with it through the MSG RAM and the "APCS mailbox".

Thanks, that's actually good description. Yet I still do not know what
is exactly the problem and the question. Linking some out of tree
commits does not give me the answer, at least I cannot get that answer
form the link.

For example what I don't understand is: why additional resources (like
resets) can be provided only in new binding, but not in the old.

Best regards,
Krzysztof