[U-Boot] [PATCH 2/6] usb: dwc2: Handle NAK during CONTROL DATA and STATUS stage

Marek Vasut
2015-12-13T04:46:42Z

On Sunday, December 13, 2015 at 05:17:54 AM, Stefan Br?ns wrote:
> A function is allowed to return NAKs during the DATA stage to control
> data flow control. NAKs during the STATUS stage signal the function
> is still processing the request.
>
> Signed-off-by: Stefan Br?ns <stefan.bruens@rwth-aachen.de>
> ---
> drivers/usb/host/dwc2.c | 37 ++++++++++++++++++++++++-------------
> 1 file changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/usb/host/dwc2.c b/drivers/usb/host/dwc2.c
> index 5ef6deb..db3acd4 100644
> --- a/drivers/usb/host/dwc2.c
> +++ b/drivers/usb/host/dwc2.c
> @@ -892,8 +892,8 @@ static int _submit_control_msg(struct dwc2_priv *priv,
> struct usb_device *dev, {
> int devnum = usb_pipedevice(pipe);
> int pid, ret, act_len;
> - /* For CONTROL endpoint pid should start with DATA1 */
> int status_direction;
> + unsigned long timeout;
>
> if (devnum == priv->root_hub_devnum) {
> dev->status = 0;
> @@ -907,26 +907,37 @@ static int _submit_control_msg(struct dwc2_priv
> *priv, struct usb_device *dev, if (ret)
> return ret;
>
> + timeout = get_timer(0) + USB_TIMEOUT_MS(pipe);
> if (buffer) {
> + /* DATA stage */
> pid = DWC2_HC_PID_DATA1;
> - ret = chunk_msg(priv, dev, pipe, &pid, usb_pipein(pipe), buffer,
> - len, false);
> + act_len = 0;
> + do {
> + if (get_timer(0) > timeout) {
> + printf("Timeout during CONTROL DATA stage\n");
> + return -ETIMEDOUT;
> + }
> + ret = chunk_msg(priv, dev, pipe, &pid, usb_pipein(pipe),
> + buffer, len, false);
> + act_len += dev->act_len;
> + buffer += dev->act_len;
> + len -= dev->act_len;
> + } while (len && (ret == -EAGAIN));

I can't say I'm a big fan of these conditions ^ . Can you rework a bit so it's
more obvious what the code does ? The condition in the while (cond) is really
inobvious at a first glance.

> if (ret)
> return ret;
> - act_len = dev->act_len;
> - } /* End of DATA stage */
> - else
> + status_direction = usb_pipeout(pipe);
> + } else {
> + /* No-data CONTROL always ends with an IN transaction */
> + status_direction = 1;
> act_len = 0;
> + }

Otherwise:
Acked-by: Marek Vasut <marex@denx.de>