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

Roger Quadros
2019-10-30T08:44:32Z

On 30/10/2019 08:36, Peter Chen wrote:
> 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;

But then it will not take care of bailing out for USB_SPEED_WIRELESS,
USB_SPEED_SUPER_PLUS and any future speeds.

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

--
cheers,
-roger

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