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Message-ID: <e5ee7051-d867-453f-98a7-3a8aea402607@linaro.org>
Date:   Tue, 31 Oct 2023 17:50:20 +0100
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Subject: Re: [PATCH v1 1/3] PCI: qcom: Enable cache coherency for SA8775P RC
Content-Language: en-US
To:     Mrinmay Sarkar <quic_msarkar@quicinc.com>, agross@kernel.org,
        andersson@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, mani@kernel.org, robh+dt@kernel.org
Cc:     quic_shazhuss@quicinc.com, quic_nitegupt@quicinc.com,
        quic_ramkri@quicinc.com, quic_nayiluri@quicinc.com,
        dmitry.baryshkov@linaro.org, robh@kernel.org,
        quic_krichai@quicinc.com, quic_vbadigan@quicinc.com,
        quic_parass@quicinc.com, quic_schintav@quicinc.com,
        quic_shijjose@quicinc.com,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
References: <1698767186-5046-1-git-send-email-quic_msarkar@quicinc.com>
 <1698767186-5046-2-git-send-email-quic_msarkar@quicinc.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
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In-Reply-To: <1698767186-5046-2-git-send-email-quic_msarkar@quicinc.com>
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On 31.10.2023 16:46, Mrinmay Sarkar wrote:
> This change will enable cache snooping logic to support
> cache coherency for SA8755P RC platform.
8775

> 
> Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 6902e97..6f240fc 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -51,6 +51,7 @@
>  #define PARF_SID_OFFSET				0x234
>  #define PARF_BDF_TRANSLATE_CFG			0x24c
>  #define PARF_SLV_ADDR_SPACE_SIZE		0x358
> +#define PCIE_PARF_NO_SNOOP_OVERIDE		0x3d4
>  #define PARF_DEVICE_TYPE			0x1000
>  #define PARF_BDF_TO_SID_TABLE_N			0x2000
>  
> @@ -117,6 +118,9 @@
>  /* PARF_LTSSM register fields */
>  #define LTSSM_EN				BIT(8)
>  
> +/* PARF_NO_SNOOP_OVERIDE register value */
override
> +#define NO_SNOOP_OVERIDE_EN			0xa
is this actually some magic value and not BIT(1) | BIT(3)?

>  /* PARF_DEVICE_TYPE register fields */
>  #define DEVICE_TYPE_RC				0x4
>  
> @@ -961,6 +965,13 @@ static int qcom_pcie_init_2_7_0(struct qcom_pcie *pcie)
>  
>  static int qcom_pcie_post_init_2_7_0(struct qcom_pcie *pcie)
>  {
> +	struct dw_pcie *pci = pcie->pci;
> +	struct device *dev = pci->dev;
> +
> +	/* Enable cache snooping for SA8775P */
> +	if (of_device_is_compatible(dev->of_node, "qcom,pcie-sa8775p"))
> +		writel(NO_SNOOP_OVERIDE_EN, pcie->parf + PCIE_PARF_NO_SNOOP_OVERIDE);
Why only for 8775 and not for other v2.7, or perhaps all other
revisions?

Konrad