linux-kernel - Re: [PATCH v2] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host

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Message-ID: <87pnide1k7.fsf@gmail.com>
Date:   Thu, 31 Oct 2019 10:55:52 +0200
From:   Felipe Balbi <balbi@...nel.org>
To:     Roger Quadros <rogerq@...com>, gregkh@...uxfoundation.org
Cc:     pawell@...ence.com, peter.chen@....com, nsekhar@...com,
        kurahul@...ence.com, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, Roger Quadros <rogerq@...com>
Subject: Re: [PATCH v2] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host


Hi,

Roger Quadros <rogerq@...com> writes:

> Take into account gadget driver's speed limit when programming
> controller speed.
>
> Fixes: commit 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
> Signed-off-by: Roger Quadros <rogerq@...com>
> Acked-by: Peter Chen <peter.chen@....com>
> ---
>
> Changelog:
> v2
> - Add Fixes line
>
>  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;
> +	}

I had suggested some simplification for this case statement.

-- 
balbi