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Date: Mon, 26 Feb 2024 12:04:33 -0500
From: Frank Li <Frank.li@nxp.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
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	Niklas Cassel <cassel@kernel.org>
Subject: Re: [PATCH v8 06/10] PCI: dwc: ep: Call dw_pcie_ep_init_registers()
 API directly from all glue drivers
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References: <20240224-pci-dbi-rework-v8-0-64c7fd0cfe64@linaro.org>
 <20240224-pci-dbi-rework-v8-6-64c7fd0cfe64@linaro.org>
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On Sat, Feb 24, 2024 at 12:24:12PM +0530, Manivannan Sadhasivam wrote:
> Currently, dw_pcie_ep_init_registers() API is directly called by the glue
> drivers requiring active refclk from host. But for the other drivers, it is
> getting called implicitly by dw_pcie_ep_init(). This is due to the fact
> that this API initializes DWC EP specific registers and that requires an
> active refclk (either from host or generated locally by endpoint itsef).
> 
> But, this causes a discrepancy among the glue drivers. So to avoid this
> confusion, let's call this API directly from all glue drivers irrespective
> of refclk dependency. Only difference here is that the drivers requiring
> refclk from host will call this API only after the refclk is received and
> other drivers without refclk dependency will call this API right after
> dw_pcie_ep_init().
> 
> This change will also allow us to remove the "core_init_notifier" flag in
> the later commits.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/controller/dwc/pci-dra7xx.c           |  7 +++++++
>  drivers/pci/controller/dwc/pci-imx6.c             |  8 ++++++++
>  drivers/pci/controller/dwc/pci-keystone.c         |  9 +++++++++
>  drivers/pci/controller/dwc/pci-layerscape-ep.c    |  7 +++++++
>  drivers/pci/controller/dwc/pcie-designware-ep.c   | 22 ----------------------
>  drivers/pci/controller/dwc/pcie-designware-plat.c |  9 +++++++++
>  drivers/pci/controller/dwc/pcie-rcar-gen4.c       | 12 +++++++++++-
>  drivers/pci/controller/dwc/pcie-uniphier-ep.c     | 13 ++++++++++++-
>  8 files changed, 63 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
> index 0e406677060d..395042b29ffc 100644
> --- a/drivers/pci/controller/dwc/pci-dra7xx.c
> +++ b/drivers/pci/controller/dwc/pci-dra7xx.c
> @@ -467,6 +467,13 @@ static int dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
>  		return ret;
>  	}
>  
> +	ret = dw_pcie_ep_init_registers(ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		dw_pcie_ep_deinit(ep);
> +		return ret;
> +	}
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> index dc2c036ab28c..bfcafa440ddb 100644
> --- a/drivers/pci/controller/dwc/pci-imx6.c
> +++ b/drivers/pci/controller/dwc/pci-imx6.c
> @@ -1136,6 +1136,14 @@ static int imx6_add_pcie_ep(struct imx6_pcie *imx6_pcie,
>  		dev_err(dev, "failed to initialize endpoint\n");
>  		return ret;
>  	}
> +
> +	ret = dw_pcie_ep_init_registers(ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		dw_pcie_ep_deinit(ep);
> +		return ret;
> +	}
> +
>  	/* Start LTSSM. */
>  	imx6_pcie_ltssm_enable(dev);
>  
> diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
> index c0c62533a3f1..8392894ed286 100644
> --- a/drivers/pci/controller/dwc/pci-keystone.c
> +++ b/drivers/pci/controller/dwc/pci-keystone.c
> @@ -1286,6 +1286,13 @@ static int ks_pcie_probe(struct platform_device *pdev)
>  		ret = dw_pcie_ep_init(&pci->ep);
>  		if (ret < 0)
>  			goto err_get_sync;
> +
> +		ret = dw_pcie_ep_init_registers(&pci->ep);
> +		if (ret < 0) {
> +			dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +			goto err_ep_init;
> +		}
> +
>  		break;
>  	default:
>  		dev_err(dev, "INVALID device type %d\n", mode);
> @@ -1295,6 +1302,8 @@ static int ks_pcie_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> +err_ep_init:
> +	dw_pcie_ep_deinit(&pci->ep);
>  err_get_sync:
>  	pm_runtime_put(dev);
>  	pm_runtime_disable(dev);
> diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> index 2e398494e7c0..b712fdd06549 100644
> --- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> @@ -276,6 +276,13 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> +	ret = dw_pcie_ep_init_registers(&pci->ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		dw_pcie_ep_deinit(&pci->ep);
> +		return ret;
> +	}
> +
>  	return ls_pcie_ep_interrupt_init(pcie, pdev);
>  }
>  
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index ed1f2afd830a..278bdc9b2269 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -729,7 +729,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>  	struct device *dev = pci->dev;
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct device_node *np = dev->of_node;
> -	const struct pci_epc_features *epc_features;
>  
>  	INIT_LIST_HEAD(&ep->func_list);
>  
> @@ -775,29 +774,8 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>  		goto err_exit_epc_mem;
>  	}
>  
> -	if (ep->ops->get_features) {
> -		epc_features = ep->ops->get_features(ep);
> -		if (epc_features->core_init_notifier)
> -			return 0;
> -	}

why remove this check?

Frank

> -
> -	/*
> -	 * NOTE:- Avoid accessing the hardware (Ex:- DBI space) before this
> -	 * step as platforms that implement 'core_init_notifier' feature may
> -	 * not have the hardware ready (i.e. core initialized) for access
> -	 * (Ex: tegra194). Any hardware access on such platforms result
> -	 * in system hang.
> -	 */
> -	ret = dw_pcie_ep_init_registers(ep);
> -	if (ret)
> -		goto err_free_epc_mem;
> -
>  	return 0;
>  
> -err_free_epc_mem:
> -	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> -			      epc->mem->window.page_size);
> -
>  err_exit_epc_mem:
>  	pci_epc_mem_exit(epc);
>  
> diff --git a/drivers/pci/controller/dwc/pcie-designware-plat.c b/drivers/pci/controller/dwc/pcie-designware-plat.c
> index 778588b4be70..ca9b22e654cd 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-plat.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-plat.c
> @@ -145,6 +145,15 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  
>  		pci->ep.ops = &pcie_ep_ops;
>  		ret = dw_pcie_ep_init(&pci->ep);
> +		if (ret)
> +			return ret;
> +
> +		ret = dw_pcie_ep_init_registers(&pci->ep);
> +		if (ret) {
> +			dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +			dw_pcie_ep_deinit(&pci->ep);
> +		}
> +
>  		break;
>  	default:
>  		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
> diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> index 9d9d22e367bb..fb7c03639a53 100644
> --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> @@ -414,6 +414,7 @@ static const struct dw_pcie_ep_ops pcie_ep_ops = {
>  static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
>  {
>  	struct dw_pcie_ep *ep = &rcar->dw.ep;
> +	struct device *dev = rcar->dw.dev;
>  	int ret;
>  
>  	if (!IS_ENABLED(CONFIG_PCIE_RCAR_GEN4_EP))
> @@ -422,8 +423,17 @@ static int rcar_gen4_add_dw_pcie_ep(struct rcar_gen4_pcie *rcar)
>  	ep->ops = &pcie_ep_ops;
>  
>  	ret = dw_pcie_ep_init(ep);
> -	if (ret)
> +	if (ret) {
>  		rcar_gen4_pcie_ep_deinit(rcar);
> +		return ret;
> +	}
> +
> +	ret = dw_pcie_ep_init_registers(ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		dw_pcie_ep_deinit(ep);
> +		rcar_gen4_pcie_ep_deinit(rcar);
> +	}
>  
>  	return ret;
>  }
> diff --git a/drivers/pci/controller/dwc/pcie-uniphier-ep.c b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
> index 3fced0d3e851..82ccaea089be 100644
> --- a/drivers/pci/controller/dwc/pcie-uniphier-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
> @@ -399,7 +399,18 @@ static int uniphier_pcie_ep_probe(struct platform_device *pdev)
>  		return ret;
>  
>  	priv->pci.ep.ops = &uniphier_pcie_ep_ops;
> -	return dw_pcie_ep_init(&priv->pci.ep);
> +	ret = dw_pcie_ep_init(&priv->pci.ep);
> +	if (ret)
> +		return ret;
> +
> +	ret = dw_pcie_ep_init_registers(&priv->pci.ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize DWC endpoint registers\n");
> +		dw_pcie_ep_deinit(&priv->pci.ep);
> +		return ret;
> +	}
> +
> +	return 0;
>  }
>  
>  static const struct uniphier_pcie_ep_soc_data uniphier_pro5_data = {
> 
> -- 
> 2.25.1
>