linux-kernel - Re: [PATCH] usb: host: xhci-plat: fix support for XHCI_SKIP_PHY

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Date:   Tue, 22 Dec 2020 02:14:45 +0000
From:   Peter Chen <peter.chen@....com>
To:     Pali Rohár <pali@...nel.org>
CC:     Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jun Li <jun.li@....com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: host: xhci-plat: fix support for XHCI_SKIP_PHY_INIT
 quirk

On 20-12-21 16:09:03, Pali Rohár wrote:
> Currently init_quirk callbacks for xhci platform drivers are called
> xhci_plat_setup() function which is called after chip reset completes.
> It happens in the middle of the usb_add_hcd() function.
> 
> But XHCI_SKIP_PHY_INIT quirk is checked in the xhci_plat_probe() function
> prior calling usb_add_hcd() function. Therefore this XHCI_SKIP_PHY_INIT
> currently does nothing as prior xhci_plat_setup() it is not set.
> 
> Quirk XHCI_SKIP_PHY_INIT is only setting hcd->skip_phy_initialization value
> which really needs to be set prior calling usb_add_hcd() as this function
> at its beginning skips PHY init if this member is set.
> 
> This patch fixes implementation of the XHCI_SKIP_PHY_INIT quirk by calling
> init_quirk callbacks (via xhci_priv_init_quirk()) prior checking if
> XHCI_SKIP_PHY_INIT is set.
> 
> Fixes: f768e718911e0 ("usb: host: xhci-plat: add priv quirk for skip PHY initialization")
> Signed-off-by: Pali Rohár <pali@...nel.org>
> ---
>  drivers/usb/host/xhci-plat.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
> index 4d34f6005381..58704c5b002b 100644
> --- a/drivers/usb/host/xhci-plat.c
> +++ b/drivers/usb/host/xhci-plat.c
> @@ -89,13 +89,6 @@ static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
>  /* called during probe() after chip reset completes */
>  static int xhci_plat_setup(struct usb_hcd *hcd)
>  {
> -	int ret;
> -
> -
> -	ret = xhci_priv_init_quirk(hcd);
> -	if (ret)
> -		return ret;
> -
>  	return xhci_gen_setup(hcd, xhci_plat_quirks);
>  }
>  
> @@ -330,6 +323,13 @@ static int xhci_plat_probe(struct platform_device *pdev)
>  
>  	hcd->tpl_support = of_usb_host_tpl_support(sysdev->of_node);
>  	xhci->shared_hcd->tpl_support = hcd->tpl_support;
> +
> +	if (priv) {
> +		ret = xhci_priv_init_quirk(hcd);
> +		if (ret)
> +			goto disable_usb_phy;
> +	}
> +
>  	if (priv && (priv->quirks & XHCI_SKIP_PHY_INIT))
>  		hcd->skip_phy_initialization = 1;
>  

Hi Pali,

What's problem you have met? In structure xhci_plat_priv, the quirks are
defined at .quirks entry which is got at below code. .init_quirk is the
routine if special initializations are needed.

	if (pdev->dev.of_node)
		priv_match = of_device_get_match_data(&pdev->dev);
	else
		priv_match = dev_get_platdata(&pdev->dev);

	if (priv_match) {
		priv = hcd_to_xhci_priv(hcd);
		/* Just copy data for now */
		*priv = *priv_match;
	}
-- 

Thanks,
Peter Chen