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Date: Fri, 5 Apr 2024 13:10:44 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Konrad Dybcio <konrad.dybcio@linaro.org>
Cc: Krishna chaitanya chundru <quic_krichai@quicinc.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
	Rob Herring <robh@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Johan Hovold <johan+linaro@kernel.org>,
	Brian Masney <bmasney@redhat.com>,
	Georgi Djakov <djakov@kernel.org>, linux-arm-msm@vger.kernel.org,
	linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, vireshk@kernel.org,
	quic_vbadigan@quicinc.com, quic_skananth@quicinc.com,
	quic_nitegupt@quicinc.com, quic_parass@quicinc.com
Subject: Re: [PATCH v8 2/7] arm64: dts: qcom: sm8450: Add interconnect path
 to PCIe node
Message-ID: <20240405074044.GC2953@thinkpad>
References: <20240302-opp_support-v8-0-158285b86b10@quicinc.com>
 <20240302-opp_support-v8-2-158285b86b10@quicinc.com>
 <4bd2e661-8e1e-41ff-9b7f-917bb92a196d@linaro.org>
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In-Reply-To: <4bd2e661-8e1e-41ff-9b7f-917bb92a196d@linaro.org>

On Wed, Mar 06, 2024 at 05:04:54PM +0100, Konrad Dybcio wrote:
> 
> 
> On 3/2/24 04:59, Krishna chaitanya chundru wrote:
> > Add pcie-mem & cpu-pcie interconnect path to the PCIe nodes.
> > 
> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> > ---
> >   arch/arm64/boot/dts/qcom/sm8450.dtsi | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/qcom/sm8450.dtsi b/arch/arm64/boot/dts/qcom/sm8450.dtsi
> > index 01e4dfc4babd..6b1d2e0d9d14 100644
> > --- a/arch/arm64/boot/dts/qcom/sm8450.dtsi
> > +++ b/arch/arm64/boot/dts/qcom/sm8450.dtsi
> > @@ -1781,6 +1781,10 @@ pcie0: pcie@1c00000 {
> >   					<0 0 0 3 &intc 0 0 0 151 IRQ_TYPE_LEVEL_HIGH>, /* int_c */
> >   					<0 0 0 4 &intc 0 0 0 152 IRQ_TYPE_LEVEL_HIGH>; /* int_d */
> > +			interconnects = <&pcie_noc MASTER_PCIE_0 0 &mc_virt SLAVE_EBI1 0>,
> 
> Please use QCOM_ICC_TAG_ALWAYS.
> 
> > +					<&gem_noc MASTER_APPSS_PROC 0 &config_noc SLAVE_PCIE_0 0>;
> 
> And this path could presumably be demoted to QCOM_ICC_TAG_ACTIVE_ONLY?
> 

I think it should be fine since there would be no register access done while the
RPMh is put into sleep state. Krishna, can you confirm that by executing the CX
shutdown with QCOM_ICC_TAG_ACTIVE_ONLY vote for cpu-pcie path on any supported
platform?

But if we do such change, then it should also be applied to other SoCs.

- Mani

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