Re: [RFC PATCH] usb: dwc3: fix maximum_speed check for usb2.0-only core

[Thinh Nguyen]

Hi,

Chunfeng Yun wrote:
> The maximum_speed will be USB_SPEED_SUPER_PLUS, but the
> maximum_speed check for usb2.0-only core doesn't consider it,
> so fix it, and move the ckeck into dwc3_check_params().
>
> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> ---
> Note:
>
> When I look at the code, find that this may be a problem, but no
> platform to test it.
> ---
>   drivers/usb/dwc3/core.c | 14 +++++++-------
>   1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index 25c686a7..ffd5ab3 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -930,13 +930,6 @@ static int dwc3_core_init(struct dwc3 *dwc)
>   	 */
>   	dwc3_writel(dwc->regs, DWC3_GUID, LINUX_VERSION_CODE);
>   
> -	/* Handle USB2.0-only core configuration */
> -	if (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
> -			DWC3_GHWPARAMS3_SSPHY_IFC_DIS) {
> -		if (dwc->maximum_speed == USB_SPEED_SUPER)
> -			dwc->maximum_speed = USB_SPEED_HIGH;
> -	}
> -
>   	ret = dwc3_phy_setup(dwc);
>   	if (ret)
>   		goto err0;
> @@ -1426,6 +1419,13 @@ static void dwc3_check_params(struct dwc3 *dwc)
>   
>   		break;
>   	}
> +
> +	/* Handle USB2.0-only core configuration */
> +	if (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
> +			DWC3_GHWPARAMS3_SSPHY_IFC_DIS) {
> +		if (dwc->maximum_speed > USB_SPEED_HIGH)
> +			dwc->maximum_speed = USB_SPEED_HIGH;
> +	}
>   }
>   
>   static int dwc3_probe(struct platform_device *pdev)

Actually, the dwc->maximum_speed captures the maximum speed device 
property value. It maybe be set based on the phy's capability if there's 
no property specifying it (i.e. maximum_speed is USB_SPEED_UNKNOWN).

So, this code should be removed. The fix should be in the check of 
dwc3_check_params(). If maximum_speed = USB_SPEED_UNKNOWN and the phy's 
capability is only up to highspeed, then set the maximum_speed to 
highspeed only.

Thanks,
Thinh