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Date:   Thu, 08 Dec 2022 10:16:27 +0100
Message-Id: <COWBMT72Y57W.2W8G3XDNT3T34@otso>
Cc:     <quic_saipraka@quicinc.com>, <konrad.dybcio@linaro.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <james.morse@arm.com>, <mchehab@kernel.org>, <rric@kernel.org>,
        <linux-edac@vger.kernel.org>, <quic_ppareek@quicinc.com>
Subject: Re: [PATCH 00/12] Qcom: LLCC/EDAC: Fix base address used for LLCC
 banks
From:   "Luca Weiss" <luca.weiss@fairphone.com>
To:     "Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
        <andersson@kernel.org>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <bp@alien8.de>,
        <tony.luck@intel.com>
References: <20221207135922.314827-1-manivannan.sadhasivam@linaro.org>
In-Reply-To: <20221207135922.314827-1-manivannan.sadhasivam@linaro.org>
Precedence: bulk

Hi Manivannan,

On Wed Dec 7, 2022 at 2:59 PM CET, Manivannan Sadhasivam wrote:
> The Qualcomm LLCC/EDAC drivers were using a fixed register stride for
> accessing the (Control and Status Regsiters) CSRs of each LLCC bank.
> This offset only works for some SoCs like SDM845 for which driver support
> was initially added.
>    =20
> But the later SoCs use different register stride that vary between the
> banks with holes in-between. So it is not possible to use a single regist=
er
> stride for accessing the CSRs of each bank. By doing so could result in a
> crash with the current drivers. So far this crash is not reported since
> EDAC_QCOM driver is not enabled in ARM64 defconfig and no one tested the
> driver extensively by triggering the EDAC IRQ (that's where each bank
> CSRs are accessed).
>    =20
> For fixing this issue, let's obtain the base address of each LLCC bank fr=
om
> devicetree and get rid of the fixed stride.
>
> This series affects multiple platforms but I have only tested this on
> SM8250 and SM8450. Testing on other platforms is welcomed.

If you can tell me *how* I can test it, I'd be happy to test the series
on sm6350, like how to trigger the EDAC IRQ.

So far without any extra patches I don't even see the driver probing,
with this in kconfig

  +CONFIG_EDAC=3Dy
  +CONFIG_EDAC_QCOM=3Dy

I do have /sys/bus/platform/drivers/qcom_llcc_edac at runtime but
nothing in there (except bind, uevent and unbind), and also nothing
interesting in dmesg with "llcc", with edac there's just this message:

  [    0.064800] EDAC MC: Ver: 3.0.0

From what I'm seeing now the edac driver is only registered if the
interrupt is specified but it doesn't seem like sm6350 (=3Dlagoon) has
this irq? Downstream dts is just this:

	cache-controller@9200000 {
		compatible =3D "lagoon-llcc-v1";
		reg =3D <0x9200000 0x50000> , <0x9600000 0x50000>;
		reg-names =3D "llcc_base", "llcc_broadcast_base";
		cap-based-alloc-and-pwr-collapse;
	};

From looking at the downstream code, perhaps it's using the polling mode
there?

	/* Request for ecc irq */
	ecc_irq =3D llcc_driv_data->ecc_irq;
	if (ecc_irq < 0) {
		dev_info(dev, "No ECC IRQ; defaulting to polling mode\n");

Let me know what you think.

Regards
Luca

>
> Thanks,
> Mani
>
> Manivannan Sadhasivam (12):
>   dt-bindings: arm: msm: Update the maintainers for LLCC
>   dt-bindings: arm: msm: Fix register regions used for LLCC banks
>   arm64: dts: qcom: sdm845: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sc7180: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sc7280: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sc8280xp: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sm8150: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sm8250: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sm8350: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sm8450: Fix the base addresses of LLCC banks
>   arm64: dts: qcom: sm6350: Fix the base addresses of LLCC banks
>   qcom: llcc/edac: Fix the base address used for accessing LLCC banks
>
>  .../bindings/arm/msm/qcom,llcc.yaml           | 128 ++++++++++++++++--
>  arch/arm64/boot/dts/qcom/sc7180.dtsi          |   2 +-
>  arch/arm64/boot/dts/qcom/sc7280.dtsi          |   5 +-
>  arch/arm64/boot/dts/qcom/sc8280xp.dtsi        |  10 +-
>  arch/arm64/boot/dts/qcom/sdm845.dtsi          |   7 +-
>  arch/arm64/boot/dts/qcom/sm6350.dtsi          |   2 +-
>  arch/arm64/boot/dts/qcom/sm8150.dtsi          |   7 +-
>  arch/arm64/boot/dts/qcom/sm8250.dtsi          |   7 +-
>  arch/arm64/boot/dts/qcom/sm8350.dtsi          |   7 +-
>  arch/arm64/boot/dts/qcom/sm8450.dtsi          |   7 +-
>  drivers/edac/qcom_edac.c                      |  14 +-
>  drivers/soc/qcom/llcc-qcom.c                  |  64 +++++----
>  include/linux/soc/qcom/llcc-qcom.h            |   4 +-
>  13 files changed, 197 insertions(+), 67 deletions(-)
>
> --=20
> 2.25.1