+static int xhci_configure_endpoint(struct xhci_hcd *xhci,
+ struct usb_device *udev, struct xhci_virt_device *virt_dev,
+ bool ctx_change);
+
+/*
+ * Full speed devices may have a max packet size greater than 8 bytes, but the
+ * USB core doesn't know that until it reads the first 8 bytes of the
+ * descriptor. If the usb_device's max packet size changes after that point,
+ * we need to issue an evaluate context command and wait on it.
+ */
+static int xhci_check_maxpacket(struct xhci_hcd *xhci, unsigned int slot_id,
+ unsigned int ep_index, struct urb *urb)
+{
+ struct xhci_container_ctx *in_ctx;
+ struct xhci_container_ctx *out_ctx;
+ struct xhci_input_control_ctx *ctrl_ctx;
+ struct xhci_ep_ctx *ep_ctx;
+ int max_packet_size;
+ int hw_max_packet_size;
+ int ret = 0;
+
+ out_ctx = xhci->devs[slot_id]->out_ctx;
+ ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
+ hw_max_packet_size = MAX_PACKET_DECODED(ep_ctx->ep_info2);
+ max_packet_size = urb->dev->ep0.desc.wMaxPacketSize;
+ if (hw_max_packet_size != max_packet_size) {
+ xhci_dbg(xhci, "Max Packet Size for ep 0 changed.\n");
+ xhci_dbg(xhci, "Max packet size in usb_device = %d\n",
+ max_packet_size);
+ xhci_dbg(xhci, "Max packet size in xHCI HW = %d\n",
+ hw_max_packet_size);
+ xhci_dbg(xhci, "Issuing evaluate context command.\n");
+
+ /* Set up the modified control endpoint 0 */
+ xhci_endpoint_copy(xhci, xhci->devs[slot_id], ep_index);
+ in_ctx = xhci->devs[slot_id]->in_ctx;
+ ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, ep_index);
+ ep_ctx->ep_info2 &= ~MAX_PACKET_MASK;
+ ep_ctx->ep_info2 |= MAX_PACKET(max_packet_size);
+
+ /* Set up the input context flags for the command */
+ /* FIXME: This won't work if a non-default control endpoint
+ * changes max packet sizes.
+ */
+ ctrl_ctx = xhci_get_input_control_ctx(xhci, in_ctx);
+ ctrl_ctx->add_flags = EP0_FLAG;
+ ctrl_ctx->drop_flags = 0;
+
+ xhci_dbg(xhci, "Slot %d input context\n", slot_id);
+ xhci_dbg_ctx(xhci, in_ctx, ep_index);
+ xhci_dbg(xhci, "Slot %d output context\n", slot_id);
+ xhci_dbg_ctx(xhci, out_ctx, ep_index);
+
+ ret = xhci_configure_endpoint(xhci, urb->dev,
+ xhci->devs[slot_id], true);
+
+ /* Clean up the input context for later use by bandwidth
+ * functions.
+ */
+ ctrl_ctx->add_flags = SLOT_FLAG;
+ }
+ return ret;
+}
+