linux-kernel - Re: [PATCH V5 2/3] PCI: qcom-ep: Refactor EP initialization completion

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Date:   Wed, 26 Oct 2022 11:00:46 +0530
From:   Manivannan Sadhasivam <mani@...nel.org>
To:     Vidya Sagar <vidyas@...dia.com>
Cc:     jingoohan1@...il.com, gustavo.pimentel@...opsys.com,
        lpieralisi@...nel.org, robh@...nel.org, kw@...ux.com,
        bhelgaas@...gle.com, Sergey.Semin@...kalelectronics.ru,
        dmitry.baryshkov@...aro.org, linmq006@...il.com,
        ffclaire1224@...il.com, thierry.reding@...il.com,
        jonathanh@...dia.com, linux-pci@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        kthota@...dia.com, mmaddireddy@...dia.com, sagar.tv@...il.com
Subject: Re: [PATCH V5 2/3] PCI: qcom-ep: Refactor EP initialization
 completion

On Thu, Oct 13, 2022 at 11:27:11PM +0530, Vidya Sagar wrote:
> Move the post initialization code to .ep_init_late() call back and call
> only dw_pcie_ep_init_notify() which internally takes care of calling
> dw_pcie_ep_init_complete().
> 
> Signed-off-by: Vidya Sagar <vidyas@...dia.com>
> ---
> V5:
> * None
> 
> V4:
> * New patch in this series
> 
>  drivers/pci/controller/dwc/pcie-qcom-ep.c | 27 ++++++++++++++---------
>  1 file changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> index e33eb3871309..c418b20042aa 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
> @@ -361,22 +361,12 @@ static int qcom_pcie_perst_deassert(struct dw_pcie *pci)
>  	      PARF_INT_ALL_LINK_UP;
>  	writel_relaxed(val, pcie_ep->parf + PARF_INT_ALL_MASK);
>  
> -	ret = dw_pcie_ep_init_complete(&pcie_ep->pci.ep);
> +	ret = dw_pcie_ep_init_notify(&pcie_ep->pci.ep);
>  	if (ret) {
>  		dev_err(dev, "Failed to complete initialization: %d\n", ret);
>  		goto err_disable_resources;
>  	}
>  
> -	/*
> -	 * The physical address of the MMIO region which is exposed as the BAR
> -	 * should be written to MHI BASE registers.
> -	 */
> -	writel_relaxed(pcie_ep->mmio_res->start,
> -		       pcie_ep->parf + PARF_MHI_BASE_ADDR_LOWER);
> -	writel_relaxed(0, pcie_ep->parf + PARF_MHI_BASE_ADDR_UPPER);

Writes to the MHI base addresses are required before starting LTSSM and not
necessarily before core_init notifier. So you could just leave this code here
and get rid of .ep_init_late() callback.

And you should also rebase the series on top of v6.1-rcX as I've added few more
code in this function.

Thanks,
Mani

> -
> -	dw_pcie_ep_init_notify(&pcie_ep->pci.ep);
> -
>  	/* Enable LTSSM */
>  	val = readl_relaxed(pcie_ep->parf + PARF_LTSSM);
>  	val |= BIT(8);
> @@ -643,8 +633,23 @@ static void qcom_pcie_ep_init(struct dw_pcie_ep *ep)
>  		dw_pcie_ep_reset_bar(pci, bar);
>  }
>  
> +static void qcom_pcie_ep_init_late(struct dw_pcie_ep *ep)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +	struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
> +
> +	/*
> +	 * The physical address of the MMIO region which is exposed as the BAR
> +	 * should be written to MHI BASE registers.
> +	 */
> +	writel_relaxed(pcie_ep->mmio_res->start,
> +		       pcie_ep->parf + PARF_MHI_BASE_ADDR_LOWER);
> +	writel_relaxed(0, pcie_ep->parf + PARF_MHI_BASE_ADDR_UPPER);
> +}
> +
>  static const struct dw_pcie_ep_ops pci_ep_ops = {
>  	.ep_init = qcom_pcie_ep_init,
> +	.ep_init_late = qcom_pcie_ep_init_late,
>  	.raise_irq = qcom_pcie_ep_raise_irq,
>  	.get_features = qcom_pcie_epc_get_features,
>  };
> -- 
> 2.17.1
> 

-- 
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