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Date:   Wed, 1 Nov 2023 12:00:41 +0530
From:   Manivannan Sadhasivam <mani@kernel.org>
To:     Krishna chaitanya chundru <quic_krichai@quicinc.com>
Cc:     agross@kernel.org, andersson@kernel.org, konrad.dybcio@linaro.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        vireshk@kernel.org, nm@ti.com, sboyd@kernel.org, mani@kernel.org,
        lpieralisi@kernel.org, kw@linux.com, robh@kernel.org,
        bhelgaas@google.com, rafael@kernel.org,
        linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org, quic_vbadigan@quicinc.com,
        quic_nitegupt@quicinc.com, quic_skananth@quicinc.com,
        quic_ramkri@quicinc.com, quic_parass@quicinc.com
Subject: Re: [PATCH v5 4/5] PCI: qcom: Return error from
 'qcom_pcie_icc_update'
Message-ID: <20231101063041.GG2897@thinkpad>
References: <1694066433-8677-1-git-send-email-quic_krichai@quicinc.com>
 <1694066433-8677-5-git-send-email-quic_krichai@quicinc.com>
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On Thu, Sep 07, 2023 at 11:30:32AM +0530, Krishna chaitanya chundru wrote:
> Return error from the function if the icc path is specified in the
> dt and icc_set_bw failed or link is not up.
> 
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>  drivers/pci/controller/dwc/pcie-qcom.c | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index e2f2940..ca6350b 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1357,22 +1357,21 @@ static int qcom_pcie_icc_init(struct qcom_pcie *pcie)
>  	return 0;
>  }
>  
> -static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
> +static int qcom_pcie_icc_update(struct qcom_pcie *pcie)
>  {
>  	struct dw_pcie *pci = pcie->pci;
>  	u32 offset, status, bw;
>  	int speed, width;
> -	int ret;
>  
>  	if (!pcie->icc_mem)
> -		return;
> +		return 0;
>  
>  	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
>  	status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
>  
>  	/* Only update constraints if link is up. */
>  	if (!(status & PCI_EXP_LNKSTA_DLLLA))
> -		return;
> +		return -ENODEV;

Why would you want to fail if the link is not up? This will break the driver if
device shows up later.

- Mani

>  
>  	speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
>  	width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
> @@ -1392,11 +1391,7 @@ static void qcom_pcie_icc_update(struct qcom_pcie *pcie)
>  		break;
>  	}
>  
> -	ret = icc_set_bw(pcie->icc_mem, 0, width * bw);
> -	if (ret) {
> -		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
> -			ret);
> -	}
> +	return icc_set_bw(pcie->icc_mem, 0, width * bw);
>  }
>  
>  static int qcom_pcie_link_transition_count(struct seq_file *s, void *data)
> @@ -1529,7 +1524,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  		goto err_phy_exit;
>  	}
>  
> -	qcom_pcie_icc_update(pcie);
> +	ret = qcom_pcie_icc_update(pcie);
> +	if (ret)
> +		dev_err(dev, "failed to update interconnect bandwidth: %d\n",
> +			ret);
>  
>  	if (pcie->mhi)
>  		qcom_pcie_init_debugfs(pcie);
> @@ -1596,7 +1594,10 @@ static int qcom_pcie_resume_noirq(struct device *dev)
>  		pcie->suspended = false;
>  	}
>  
> -	qcom_pcie_icc_update(pcie);
> +	ret = qcom_pcie_icc_update(pcie);
> +	if (ret)
> +		dev_err(dev, "failed to update interconnect bandwidth: %d\n",
> +			ret);
>  
>  	return 0;
>  }
> -- 
> 2.7.4
> 

-- 
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