Re: [PATCH v3] char: xillybus: Check endpoint type at probe time

Eli Billauer
2022-05-30T15:50:44Z

On 29/05/22 09:58, Zheyu Ma wrote:
> static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
> {
> + int ret;
> + struct usb_endpoint_descriptor *in, *out;
> +
> + ret = usb_find_common_endpoints(xdev->intf->cur_altsetting,&in,&out, NULL, NULL);
> + if (ret)
> + return ret;
> +
> + if (in->bEndpointAddress != (IN_EP_NUM | USB_DIR_IN) ||
> + out->bEndpointAddress != (MSG_EP_NUM | USB_DIR_OUT))
> + return -EINVAL;
> +
>
As far as I understand, this finds the first BULK endpoints in both
directions, and verifies that their addresses are MSG_EP_NUM and
IN_EP_NUM. Because both of these happen to equal 1, I suppose this
indeed checks the right thing. But am I right that this won't work if
either MSG_EP_NUM or IN_EP_NUM have a value that isn't 1? Not that I
think that will ever happen, but still.

> +static int xillyusb_check_endpoint(struct xillyusb_dev *xdev, u8 addr)
> +{
> + int i;
> + struct usb_host_interface *if_desc = xdev->intf->altsetting;
> +
> + for (i = 0; i< if_desc->desc.bNumEndpoints; i++) {
> + struct usb_endpoint_descriptor *ep =&if_desc->endpoint[i].desc;
> +
> + if (ep->bEndpointAddress == addr&& usb_endpoint_is_bulk_out(ep))
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
>
>
Given that you've added this function, why isn't it used in
xillyusb_setup_base_eps()?

Thanks,
Eli