Re: [PATCH] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host

Peter Chen
2019-10-30T06:36:54Z

On 19-10-29 17:15:14, Roger Quadros wrote:
> Take into account gadget driver's speed limit when programming
> controller speed.
>
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
> Hi Greg,
>
> Please apply this for -rc.
> Without this, g_audio is broken on cdns3 USB controller is
> connected to a Super-Speed host.
>
> cheers,
> -roger
>
> drivers/usb/cdns3/gadget.c | 31 ++++++++++++++++++++++++++-----
> 1 file changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
> index 40dad4e8d0dc..1c724c20d468 100644
> --- a/drivers/usb/cdns3/gadget.c
> +++ b/drivers/usb/cdns3/gadget.c
> @@ -2338,9 +2338,35 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
> {
> struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
> unsigned long flags;
> + enum usb_device_speed max_speed = driver->max_speed;
>
> spin_lock_irqsave(&priv_dev->lock, flags);
> priv_dev->gadget_driver = driver;
> +
> + /* limit speed if necessary */
> + max_speed = min(driver->max_speed, gadget->max_speed);
> +
> + switch (max_speed) {
> + case USB_SPEED_FULL:
> + writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> + writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> + break;
> + case USB_SPEED_HIGH:
> + writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> + break;
> + case USB_SPEED_SUPER:
> + break;
> + default:
> + dev_err(priv_dev->dev,
> + "invalid maximum_speed parameter %d\n",
> + max_speed);
> + /* fall through */
> + case USB_SPEED_UNKNOWN:
> + /* default to superspeed */
> + max_speed = USB_SPEED_SUPER;
> + break;
> + }
> +
> cdns3_gadget_config(priv_dev);
> spin_unlock_irqrestore(&priv_dev->lock, flags);
> return 0;
> @@ -2570,12 +2596,7 @@ static int cdns3_gadget_start(struct cdns3 *cdns)
> /* Check the maximum_speed parameter */
> switch (max_speed) {
> case USB_SPEED_FULL:
> - writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
> - writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> - break;
> case USB_SPEED_HIGH:
> - writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
> - break;
> case USB_SPEED_SUPER:
> break;
> default:

Just a small comment:

You could delete switch-case at cdns3_gadget_start, and just use
if() statement, eg:

max_speed = usb_get_maximum_speed(cdns->dev);
if (max_speed == USB_SPEED_UNKNOWN)
max_speed = USB_SPEED_SUPER;

Otherwise:

Acked-by: Peter Chen <peter.chen@nxp.com>

--

Thanks,
Peter Chen