linux-kernel - Re: [PATCH v2] PCI: qcom: Fix error handling in pm

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Message-ID: <20180917104502.GD7239@e107981-ln.cambridge.arm.com>
Date:   Mon, 17 Sep 2018 11:45:02 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Stanimir Varbanov <svarbanov@...sol.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PCI: qcom: Fix error handling in pm_runtime support

On Fri, Aug 31, 2018 at 03:55:10PM -0700, Bjorn Andersson wrote:
> The driver does not cope with the fact that probe can fail in a number
> of cases after enabling pm_runtime on the device, this results in
> warnings about "Unbalanced pm_runtime_enable". Further more if probe
> fails after invoking host_init the power-domain will be left referenced.
> 
> As it's not possible for the error handling in qcom_pcie_host_init() to
> handle errors happening after returning from that function the
> pm_runtime_get_sync() is moved to probe() as well.
> 
> Fixes: 854b69efbdd2 ("PCI: qcom: add runtime pm support to pcie_port")
> Acked-by: Stanimir Varbanov <svarbanov@...sol.com>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
> 
> Changes since v1:
> - Dropped remove function, as this can't be called
> - Handle pm_runtime_get_sync() errors
> - Add "Fixes" tag
> 
>  drivers/pci/controller/dwc/pcie-qcom.c | 56 ++++++++++++++++++--------
>  1 file changed, 39 insertions(+), 17 deletions(-)

Applied to pci/dwc for v4.20, thanks.

Lorenzo

> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index d2373e4d141c..3bfaad052736 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -1117,7 +1117,6 @@ static int qcom_pcie_host_init(struct pcie_port *pp)
>  	struct qcom_pcie *pcie = to_qcom_pcie(pci);
>  	int ret;
>  
> -	pm_runtime_get_sync(pci->dev);
>  	qcom_ep_reset_assert(pcie);
>  
>  	ret = pcie->ops->init(pcie);
> @@ -1154,7 +1153,6 @@ static int qcom_pcie_host_init(struct pcie_port *pp)
>  	phy_power_off(pcie->phy);
>  err_deinit:
>  	pcie->ops->deinit(pcie);
> -	pm_runtime_put(pci->dev);
>  
>  	return ret;
>  }
> @@ -1244,6 +1242,12 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	pm_runtime_enable(dev);
> +	ret = pm_runtime_get_sync(dev);
> +	if (ret < 0) {
> +		pm_runtime_disable(dev);
> +		return ret;
> +	}
> +
>  	pci->dev = dev;
>  	pci->ops = &dw_pcie_ops;
>  	pp = &pci->pp;
> @@ -1253,44 +1257,56 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	pcie->ops = of_device_get_match_data(dev);
>  
>  	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_LOW);
> -	if (IS_ERR(pcie->reset))
> -		return PTR_ERR(pcie->reset);
> +	if (IS_ERR(pcie->reset)) {
> +		ret = PTR_ERR(pcie->reset);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
>  	pcie->parf = devm_ioremap_resource(dev, res);
> -	if (IS_ERR(pcie->parf))
> -		return PTR_ERR(pcie->parf);
> +	if (IS_ERR(pcie->parf)) {
> +		ret = PTR_ERR(pcie->parf);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
>  	pci->dbi_base = devm_pci_remap_cfg_resource(dev, res);
> -	if (IS_ERR(pci->dbi_base))
> -		return PTR_ERR(pci->dbi_base);
> +	if (IS_ERR(pci->dbi_base)) {
> +		ret = PTR_ERR(pci->dbi_base);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
>  	pcie->elbi = devm_ioremap_resource(dev, res);
> -	if (IS_ERR(pcie->elbi))
> -		return PTR_ERR(pcie->elbi);
> +	if (IS_ERR(pcie->elbi)) {
> +		ret = PTR_ERR(pcie->elbi);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	pcie->phy = devm_phy_optional_get(dev, "pciephy");
> -	if (IS_ERR(pcie->phy))
> -		return PTR_ERR(pcie->phy);
> +	if (IS_ERR(pcie->phy)) {
> +		ret = PTR_ERR(pcie->phy);
> +		goto err_pm_runtime_put;
> +	}
>  
>  	ret = pcie->ops->get_resources(pcie);
>  	if (ret)
> -		return ret;
> +		goto err_pm_runtime_put;
>  
>  	pp->ops = &qcom_pcie_dw_ops;
>  
>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
>  		pp->msi_irq = platform_get_irq_byname(pdev, "msi");
> -		if (pp->msi_irq < 0)
> -			return pp->msi_irq;
> +		if (pp->msi_irq < 0) {
> +			ret = pp->msi_irq;
> +			goto err_pm_runtime_put;
> +		}
>  	}
>  
>  	ret = phy_init(pcie->phy);
>  	if (ret) {
>  		pm_runtime_disable(&pdev->dev);
> -		return ret;
> +		goto err_pm_runtime_put;
>  	}
>  
>  	platform_set_drvdata(pdev, pcie);
> @@ -1299,10 +1315,16 @@ static int qcom_pcie_probe(struct platform_device *pdev)
>  	if (ret) {
>  		dev_err(dev, "cannot initialize host\n");
>  		pm_runtime_disable(&pdev->dev);
> -		return ret;
> +		goto err_pm_runtime_put;
>  	}
>  
>  	return 0;
> +
> +err_pm_runtime_put:
> +	pm_runtime_put(dev);
> +	pm_runtime_disable(dev);
> +
> +	return ret;
>  }
>  
>  static const struct of_device_id qcom_pcie_match[] = {
> -- 
> 2.18.0
>