linux-kernel - Re: [PATCH] ARM: dts: exynos: add CCI-400 PMU nodes support to Exynos542x SoCs

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Message-ID: <CAJKOXPf-CLMh1kLux0ev4FkT4x8CB+5O1wSNFmkjhFtVatX8jQ@mail.gmail.com>
Date:   Wed, 17 Apr 2019 09:44:47 +0200
From:   Krzysztof Kozlowski <krzk@...nel.org>
To:     Anand Moon <linux.amoon@...il.com>
Cc:     Willy Wolff <willy.mh.wolff.ml@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Kukjin Kim <kgene@...nel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        "linux-samsung-soc@...r.kernel.org" 
        <linux-samsung-soc@...r.kernel.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: dts: exynos: add CCI-400 PMU nodes support to
 Exynos542x SoCs

On Wed, 17 Apr 2019 at 06:26, Anand Moon <linux.amoon@...il.com> wrote:
>
> Hi Krzysztof,
>
> On Tue, 16 Apr 2019 at 15:49, Krzysztof Kozlowski <krzk@...nel.org> wrote:
> >
> > On Mon, 15 Apr 2019 at 14:24, Anand Moon <linux.amoon@...il.com> wrote:
> > > Cache Coherent Interface (CCI) among Cortex-A15 and Cortex-A7, G2D, G3D and SSS
> > >
> > > Level 0 > CPU blocks such as Cortex-A15 (CA15), Cortex-A7 (CA7) are
> > > joined as the member of Level 0 CCI bus
> > >
> > > Level 1 > Display engine block (DISP) and 2D graphic engines (G2D) are
> > > directly connected to Level 1.
> > >   DISP, MDMA, SSS.
> > >
> > > Level 2 > While all the other IP is connected to Level 1 bus via Level 2 bus
> > >    G3D, MSCL, MFC, ISP, JPEG/Rotator/DMA/PERI, NAND/SD/EMMC.
> > >
> > > So my question is the mapped with the cci ip block correct.
> > > Level 0 (cci_control0)
> > > Level 1 (cci_control1)
> > > Level 2 (cci_control1)
> >
> > Hi Anand,
> >
> > I do not understand the question - what is mapped with correctly or not?
> >
> > Best regards,
> > Krzysztof
>
> Following the https://www.kernel.org/doc/Documentation/devicetree/bindings/arm/cci.txt
> CCI node linked to CPU and DMA nodes for example.
>
> On this line below diagram from Exynos 5422 UM show various IP block
> linked to CCI level.
> Below image just elaborate overall architecture of Exynos 5422 CCI.
>
> [0] https://imgur.com/gallery/0xJSwGQ
>
> So we should map the various IP block to corresponding CCI level.

Willy's patch did not touch cci_control{0,1} nor any other CCI levels
so I do not get what are you commenting. As for other CCI ports - we
do not define them and I do not see any users of device CCI API
(cci_enable_port_by_device() and cci_disable_port_by_device()). But
feel free to propose patches changing this. In general - it is easier
to discuss if you show the code/patch, not talk about some theoretical
change.

Best regards,
Krzysztof