RE: [PATCH v4 2/5] usb: phy: Workaround for USB erratum-A005728

[Yinbo Zhu <yinbo.zhu@nxp.com>]

> -----Original Message-----
> From: Alan Stern [mailto:stern@rowland.harvard.edu]
> Sent: 2019年1月28日 23:37
> To: Yinbo Zhu <yinbo.zhu@nxp.com>
> Cc: Xiaobo Xie <xiaobo.xie@nxp.com>; Jerry Huang <jerry.huang@nxp.com>;
> Ran Wang <ran.wang_1@nxp.com>; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>; Ramneek Mehresh
> <ramneek.mehresh@freescale.com>; Nikhil Badola
> <nikhil.badola@freescale.com>; Suresh Gupta <suresh.gupta@freescale.com>;
> linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org; Suresh Gupta
> <B42813@freescale.com>
> Subject: Re: [PATCH v4 2/5] usb: phy: Workaround for USB erratum-A005728
> 
> On Fri, 25 Jan 2019, Yinbo Zhu wrote:
> 
> > From: Suresh Gupta <B42813@freescale.com>
> >
> > PHY_CLK_VALID bit for UTMI PHY in USBDR does not set even if PHY is
> > providing valid clock. Workaround for this involves resetting of PHY
> > and check PHY_CLK_VALID bit multiple times. If PHY_CLK_VALID bit is
> > still not set even after 5 retries, it would be safe to deaclare that
> > PHY clock is not available.
> > This erratum is applicable for USBDR less then ver 2.4.
> >
> > Signed-off-by: Suresh Gupta <B42813@freescale.com>
> > Signed-off-by: Yinbo Zhu <yinbo.zhu@nxp.com>
> > ---
> > Change in v4:
> > 		Incorrect indentation of the continuation line.
> > 		replace pr_err with dev_err.
> >
> >  drivers/usb/host/ehci-fsl.c |   38
> +++++++++++++++++++++++++++-----------
> >  drivers/usb/host/ehci-fsl.h |    3 +++
> >  2 files changed, 30 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
> > index 38674b7..373a816 100644
> > --- a/drivers/usb/host/ehci-fsl.c
> > +++ b/drivers/usb/host/ehci-fsl.c
> > @@ -183,6 +183,17 @@ static int fsl_ehci_drv_probe(struct platform_device
> *pdev)
> >  	return retval;
> >  }
> >
> > +static bool usb_phy_clk_valid(struct usb_hcd *hcd) {
> > +	void __iomem *non_ehci = hcd->regs;
> > +	bool ret = true;
> > +
> > +	if (!(ioread32be(non_ehci + FSL_SOC_USB_CTRL) & PHY_CLK_VALID))
> > +		ret = false;
> > +
> > +	return ret;
> > +}
> > +
> >  static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
> >  			       enum fsl_usb2_phy_modes phy_mode,
> >  			       unsigned int port_offset)
> > @@ -226,6 +237,17 @@ static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
> >  		/* fall through */
> >  	case FSL_USB2_PHY_UTMI:
> >  	case FSL_USB2_PHY_UTMI_DUAL:
> > +		/* PHY_CLK_VALID bit is de-featured from all controller
> > +		 * versions below 2.4 and is to be checked only for
> > +		 * internal UTMI phy
> > +		 */
> > +		if (pdata->controller_ver > FSL_USB_VER_2_4 &&
> > +		    pdata->have_sysif_regs && !usb_phy_clk_valid(hcd)) {
> > +			dev_err(dev,
> > +				"%s: USB PHY clock invalid\n", dev_name(dev));
> 
> This looks silly; it prints the device name twice (once because that's what
> dev_err() does, and then again because you explicitly told it to print the device
> name).
> 
> Look at how dev_err() is used in other parts of the driver and do the same thing.
> 
> > +			return -EINVAL;
> > +		}
> > +
> >  		if (pdata->have_sysif_regs && pdata->controller_ver) {
> >  			/* controller version 1.6 or above */
> >  			tmp = ioread32be(non_ehci + FSL_SOC_USB_CTRL); @@ -249,17
> +271,11
> > @@ static int ehci_fsl_setup_phy(struct usb_hcd *hcd,
> >  		break;
> >  	}
> >
> > -	/*
> > -	 * check PHY_CLK_VALID to determine phy clock presence before writing
> > -	 * to portsc
> > -	 */
> > -	if (pdata->check_phy_clk_valid) {
> > -		if (!(ioread32be(non_ehci + FSL_SOC_USB_CTRL) &
> > -		    PHY_CLK_VALID)) {
> > -			dev_warn(hcd->self.controller,
> > -				 "USB PHY clock invalid\n");
> > -			return -EINVAL;
> > -		}
> > +	if (pdata->have_sysif_regs &&
> > +	    pdata->controller_ver > FSL_USB_VER_1_6 &&
> > +		!usb_phy_clk_valid(hcd)) {
> > +		dev_warn(hcd->self.controller, "USB PHY clock invalid\n");
> 
> Once again, you have a continuation line that is indented by the same amount as
> the code in the inner block.  Please fix this properly.
Hi Alan stern,

Above code indented is in oder to ensure that every line less than 80 characters,
Otherwise, check-patch tool to check patch that will has error.

Regards,
Yinbo
> > +		return -EINVAL;
> >  	}
> >
> >  	ehci_writel(ehci, portsc, &ehci->regs->port_status[port_offset]);
> > diff --git a/drivers/usb/host/ehci-fsl.h b/drivers/usb/host/ehci-fsl.h
> > index cbc4220..9d18c6e 100644
> > --- a/drivers/usb/host/ehci-fsl.h
> > +++ b/drivers/usb/host/ehci-fsl.h
> > @@ -50,4 +50,7 @@
> >  #define UTMI_PHY_EN             (1<<9)
> >  #define ULPI_PHY_CLK_SEL        (1<<10)
> >  #define PHY_CLK_VALID		(1<<17)
> > +
> > +/* Retry count for checking UTMI PHY CLK validity */ #define
> > +UTMI_PHY_CLK_VALID_CHK_RETRY 5
> >  #endif				/* _EHCI_FSL_H */
> 
> Alan Stern