linux-kernel - Re: [PATCH v3 2/5] usb: dwc3: host: Add suspend

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Message-ID: <20200929185006.GC1621304@google.com>
Date:   Tue, 29 Sep 2020 11:50:06 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Sandeep Maheswaram <sanm@...eaurora.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Felipe Balbi <balbi@...nel.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        linux-arm-msm@...r.kernel.org, linux-usb@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Manu Gautam <mgautam@...eaurora.org>
Subject: Re: [PATCH v3 2/5] usb: dwc3: host: Add suspend_quirk for dwc3 host

On Tue, Sep 29, 2020 at 04:17:29PM +0530, Sandeep Maheswaram wrote:
> Adding suspend quirk function for dwc3 host which will be called
> during xhci suspend.
> Setting hs_phy_flags, ss_phy_flags and phy mode during host suspend.
> 
> Signed-off-by: Sandeep Maheswaram <sanm@...eaurora.org>
> ---
>  drivers/usb/dwc3/host.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
> index e195176..7f316fa 100644
> --- a/drivers/usb/dwc3/host.c
> +++ b/drivers/usb/dwc3/host.c
> @@ -11,6 +11,13 @@
>  #include <linux/platform_device.h>
>  
>  #include "core.h"
> +#include "../host/xhci.h"
> +#include "../host/xhci-plat.h"
> +int xhci_dwc3_suspend_quirk(struct usb_hcd *hcd);
> +
> +static const struct xhci_plat_priv xhci_plat_dwc3_xhci = {
> +	.suspend_quirk = xhci_dwc3_suspend_quirk,
> +};
>  
>  static int dwc3_host_get_irq(struct dwc3 *dwc)
>  {
> @@ -115,6 +122,13 @@ int dwc3_host_init(struct dwc3 *dwc)
>  		}
>  	}
>  
> +	ret = platform_device_add_data(xhci, &xhci_plat_dwc3_xhci,
> +			sizeof(struct xhci_plat_priv));
> +	if (ret) {
> +		dev_err(dwc->dev, "failed to add data to xHCI\n");
> +		goto err;
> +	}
> +
>  	ret = platform_device_add(xhci);
>  	if (ret) {
>  		dev_err(dwc->dev, "failed to register xHCI device\n");
> @@ -127,6 +141,41 @@ int dwc3_host_init(struct dwc3 *dwc)
>  	return ret;
>  }
>  
> +static void dwc3_set_phy_speed_flags(struct usb_hcd *hcd)

The main thing this function does is setting the PHY mode (see
the phy_set_mode() calls), please rename it to dwc3_set_phy_mode()
to reflect this.

> +{
> +
> +	int i, num_ports;
> +	u32 reg;
> +	struct device *dev = hcd->self.controller;
> +	struct dwc3 *dwc = dev_get_drvdata(dev->parent);
> +	struct xhci_hcd	*xhci_hcd = hcd_to_xhci(hcd);
> +
> +	dwc->hs_phy_flags = 0;

What about 'dwc->ss_phy_flags'?

I suggested in another patch to use a local variable instead, so you
probably have to initialize it anyway or the compiler will be unhappy ;-)

> +
> +	reg = readl(&xhci_hcd->cap_regs->hcs_params1);
> +
> +	num_ports = HCS_MAX_PORTS(reg);
> +	for (i = 0; i < num_ports; i++) {
> +		reg = readl(&xhci_hcd->op_regs->port_status_base + i * 0x04);
> +		if (reg & PORT_PE) {
> +			if (DEV_HIGHSPEED(reg) || DEV_FULLSPEED(reg))
> +				dwc->hs_phy_flags |= PHY_MODE_USB_HOST_HS;
> +			else if (DEV_LOWSPEED(reg))
> +				dwc->hs_phy_flags |= PHY_MODE_USB_HOST_LS;

nit: add empty line to visually separate HS from SS

> +			if (DEV_SUPERSPEED(reg))
> +				dwc->ss_phy_flags |= PHY_MODE_USB_HOST_SS;
> +		}
> +	}
> +	phy_set_mode(dwc->usb2_generic_phy, dwc->hs_phy_flags);
> +	phy_set_mode(dwc->usb3_generic_phy, dwc->ss_phy_flags);

Check return values and return any errors?