RE: [PATCH 1/3] net: cdc_ncm: add get/set ethernet address functions

[<Charles.Hyde@xxxxxxxxxxxx>]

<snipped> 
> static int cdc_ncm_init(struct usbnet *dev) {
> 	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
> 	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;
> 	int err;
> 
> 	err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_PARAMETERS,
> 			      USB_TYPE_CLASS | USB_DIR_IN
> 			      |USB_RECIP_INTERFACE,
> 			      0, iface_no, &ctx->ncm_parm,
> 			      sizeof(ctx->ncm_parm));
> ,,
> 
> You'll obviously have to replace USB_CDC_GET_NTB_PARAMETERS with
> USB_CDC_GET_NET_ADDRESS, &ctx->ncm_parm with buf, and
> sizeof(ctx->ncm_parm) with ETH_ALEN.
> 
> 
> Bjørn

Not everything is obvious to those who do not live and breathe USB.  This has been an experience.

Is this snippet what you have in mind?  Will iface_no be correct?  If not, then what do you suggest?

/* Provide method to push MAC address to the USB device's ethernet controller.
 * If the device does not support CDC_SET_ADDRESS, there is no harm and we
 * proceed as before.
 */
static int cdc_ncm_set_ethernet_address(struct usbnet *dev,
					struct sockaddr *addr)
{
	int ret;
	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];
	u8 iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;

	ret = usbnet_write_cmd(dev, USB_CDC_SET_NET_ADDRESS,
			       USB_DIR_OUT | USB_TYPE_CLASS
			       | USB_RECIP_INTERFACE, 0, iface_no,
			       addr->sa_data, ETH_ALEN);
	if (ret == ETH_ALEN)
		ret = 0;	/* success */
	else if (ret < 0)
		dev_dbg(&dev->udev->dev, "bad MAC address put, %d\n", ret);

	return ret;
}