linux-kernel - Re: [PATCH v6 5/6] arm64: dts: qcom: sm8450: Add opp table support to PCIe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240131052335.6nqpmccgr64voque@vireshk-i7>
Date: Wed, 31 Jan 2024 10:53:35 +0530
From: Viresh Kumar <viresh.kumar@...aro.org>
To: Manivannan Sadhasivam <mani@...nel.org>
Cc: Krishna chaitanya chundru <quic_krichai@...cinc.com>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Rob Herring <robh+dt@...nel.org>,
	Johan Hovold <johan+linaro@...nel.org>,
	Brian Masney <bmasney@...hat.com>,
	Georgi Djakov <djakov@...nel.org>, linux-arm-msm@...r.kernel.org,
	vireshk@...nel.org, quic_vbadigan@...cinc.com,
	quic_skananth@...cinc.com, quic_nitegupt@...cinc.com,
	linux-pci@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 5/6] arm64: dts: qcom: sm8450: Add opp table support
 to PCIe

On 30-01-24, 18:46, Manivannan Sadhasivam wrote:
> Agree. But what I'm saying is, right now there is no DT property in the
> interconnect consumer nodes to specificy the bw requirements. This is all
> hardcoded in the respective ICC consumer drivers.

I thought there are a lot of users already in there..

$ git grep -i opp.*bps arch/arm64/boot/dts/ | wc -l
864

> But when we use OPP to control bw, the bw requirements come from DT. This is
> what I see as a difference. Because, only nodes making use of OPP will specify
> bw in DT and other nodes making use of just ICC will not.
> 
> Maybe I'm worrying too much about these details... But it looks like
> inconsistency to me.

Right. So is there inconsistency right now ? Yes, there is.

The important question we need to answer is where do we want to see
all these drivers (specially new ones) in the future. What's the right
thing to do eventually ? Hardcode stuff ? Or Move it to DT ?

The answer is DT for me, so the code can be generic enough to be
reused. This is just one step in the right direction I guess.
Eventually the drivers must get simplified, which they are I guess.

-- 
viresh