linux-kernel - Re: [PATCHv4 1/4] arm64: dts: qcom: sdm845: Add Coresight support

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Message-ID: <CANLsYkxkTTfTMNNZZ1tmS=cjakcfveMDrW6wxXPXie8M9_VDOg@mail.gmail.com>
Date:   Mon, 28 Jan 2019 10:15:08 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
Cc:     Suzuki K Poulose <suzuki.poulose@....com>,
        Rob Herring <robh+dt@...nel.org>, Leo Yan <leo.yan@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Doug Anderson <dianders@...omium.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        devicetree@...r.kernel.org, Mark Rutland <mark.rutland@....com>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Sibi Sankar <sibis@...eaurora.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        John Horley <John.Horley@....com>
Subject: Re: [PATCHv4 1/4] arm64: dts: qcom: sdm845: Add Coresight support

On Thu, 24 Jan 2019 at 11:21, Sai Prakash Ranjan
<saiprakash.ranjan@...eaurora.org> wrote:
>
> Hi Suzuki,
>
> On 1/24/2019 4:49 PM, Suzuki K Poulose wrote:
> > Hi Sai,
> >
> >
> > That looks fine with me. But as Mathieu said, this needs to be a separate
> > patch. But before all that please could you provide me the PIDR4 value for
> > the Kryo A75 and A55 please ?
> >
>
> Sure.
>
> PIDR4 value is 0x4.
>
> I get it now. So we are looking for JEP106 identification(PIDR1[7:4] and
> PIDR2[2:0]) and continuation code(PIDR4[3:0]).
>
>  From ARM Coresight Spec:
>
> DES_0, PIDR1 bits[7:4] JEP106 identification code bits[3:0].
> DES_1, PIDR2 bits[2:0] JEP106 identification code bits[6:4].
> DES_2, PIDR4 bits[3:0] JEP106 continuation code.
>
> For SDM845(A75 based):
>
> *0xB_B8_03* does indicate that the JEP106 identification
> code is 0x3B and continuation code is 0x4 which is of ARM and not
> QCOM(JEP106 ID is 0x70) which is expected.
>
> And the other values of PIDR0[0:7] and PIDR1[3:0] are *Implementation
> defined part numbers* and can be different from ARM A75/A55.
>
> I think this clears up case for SDM845.
>
> As for MSM8996, it is not based on any ARM derivative and hence the
> JEP106 ID is of QCOM(0x70) from the value of pid = *0xF_02_11*
> based on PIDR1[7:4] and PIDR2[2:0]. This clears this as well.
>
> Please correct me if I am wrong and also let me know if I can
> continue with PID addition to table.

Please proceed.

>
> Thanks,
> Sai
>
> --
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