[usb] Add clear_tt() hub method to clear transaction translator buffer

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/usb/ehci.c

 		/* No way to prevent hardware from continuing to
 		 * access the memory, so leak it.
 		 */
-		DBGC ( ehci, "EHCI %p %s endpoint %d could not unschedule: "
+		DBGC ( ehci, "EHCI %p %s endpoint %02x could not unschedule: "
 		       "%s\n", ehci, usb->name, ep->address, strerror ( rc ) );
 		return;
 	}
 		 */
 		if ( status & EHCI_STATUS_HALTED ) {
 			rc = -EIO_STATUS ( status );
-			DBGC ( ehci, "EHCI %p %s endpoint %d completion %d "
+			DBGC ( ehci, "EHCI %p %s endpoint %02x completion %d "
 			       "failed (status %02x): %s\n", ehci, usb->name,
 			       ep->address, index, status, strerror ( rc ) );
 			while ( ! iobuf )
 	return 0;
 }
 
+/**
+ * Clear transaction translator buffer
+ *
+ * @v hub		USB hub
+ * @v port		USB port
+ * @v ep		USB endpoint
+ * @ret rc		Return status code
+ */
+static int ehci_hub_clear_tt ( struct usb_hub *hub, struct usb_port *port,
+			       struct usb_endpoint *ep ) {
+	struct ehci_device *ehci = usb_hub_get_drvdata ( hub );
+
+	/* Should never be called; this is a root hub */
+	DBGC ( ehci, "EHCI %p port %d nonsensical CLEAR_TT for %s endpoint "
+	       "%02x\n", ehci, port->address, ep->usb->name, ep->address );
+
+	return -ENOTSUP;
+}
+
 /**
  * Poll for port status changes
  *
 		.enable = ehci_hub_enable,
 		.disable = ehci_hub_disable,
 		.speed = ehci_hub_speed,
+		.clear_tt = ehci_hub_clear_tt,
 	},
 };
 

src/drivers/usb/usbhub.c

 	return 0;
 }
 
+/**
+ * Clear transaction translator buffer
+ *
+ * @v hub		USB hub
+ * @v port		USB port
+ * @v ep		USB endpoint
+ * @ret rc		Return status code
+ */
+static int hub_clear_tt ( struct usb_hub *hub, struct usb_port *port,
+			  struct usb_endpoint *ep ) {
+	struct usb_hub_device *hubdev = usb_hub_get_drvdata ( hub );
+	struct usb_device *usb = hubdev->usb;
+	int rc;
+
+	/* Clear transaction translator buffer.  All hubs must support
+	 * single-TT operation; we simplify our code by supporting
+	 * only this configuration.
+	 */
+	if ( ( rc = usb_hub_clear_tt_buffer ( usb, ep->usb->address,
+					      ep->address, ep->attributes,
+					      USB_HUB_TT_SINGLE ) ) != 0 ) {
+		DBGC ( hubdev, "HUB %s port %d could not clear TT buffer: %s\n",
+		       hubdev->name, port->address, strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
 /** USB hub operations */
 static struct usb_hub_driver_operations hub_operations = {
 	.open = hub_open,
 	.enable = hub_enable,
 	.disable = hub_disable,
 	.speed = hub_speed,
+	.clear_tt = hub_clear_tt,
 };
 
 /**

src/drivers/usb/usbhub.h

 	( USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_DEVICE |		\
 	  USB_REQUEST_TYPE ( 12 ) )
 
+/** Clear transaction translator buffer */
+#define USB_HUB_CLEAR_TT_BUFFER						\
+	( USB_DIR_OUT | USB_TYPE_CLASS | USB_HUB_RECIP_PORT |		\
+	  USB_REQUEST_TYPE ( 8 ) )
+
 /**
  * Get hub descriptor
  *
 	return usb_control ( usb, USB_HUB_SET_HUB_DEPTH, depth, 0, NULL, 0 );
 }
 
+/**
+ * Clear transaction translator buffer
+ *
+ * @v usb		USB device
+ * @v device		Device address
+ * @v endpoint		Endpoint address
+ * @v attributes	Endpoint attributes
+ * @v tt_port		Transaction translator port (or 1 for single-TT hubs)
+ * @ret rc		Return status code
+ */
+static inline __attribute__ (( always_inline )) int
+usb_hub_clear_tt_buffer ( struct usb_device *usb, unsigned int device,
+			  unsigned int endpoint, unsigned int attributes,
+			  unsigned int tt_port ) {
+	unsigned int value;
+
+	/* Calculate value */
+	value = ( ( ( endpoint & USB_ENDPOINT_MAX ) << 0 ) | ( device << 4 ) |
+		  ( ( attributes & USB_ENDPOINT_ATTR_TYPE_MASK ) << 11 ) |
+		  ( ( endpoint & USB_ENDPOINT_IN ) << 8 ) );
+
+	return usb_control ( usb, USB_HUB_CLEAR_TT_BUFFER, value,
+			     tt_port, NULL, 0 );
+}
+
+/** Transaction translator port value for single-TT hubs */
+#define USB_HUB_TT_SINGLE 1
+
 /** A USB hub device */
 struct usb_hub_device {
 	/** Name */

src/drivers/usb/xhci.c

 	return 0;
 }
 
+/**
+ * Clear transaction translator buffer
+ *
+ * @v hub		USB hub
+ * @v port		USB port
+ * @v ep		USB endpoint
+ * @ret rc		Return status code
+ */
+static int xhci_hub_clear_tt ( struct usb_hub *hub, struct usb_port *port,
+			       struct usb_endpoint *ep ) {
+	struct ehci_device *ehci = usb_hub_get_drvdata ( hub );
+
+	/* Should never be called; this is a root hub */
+	DBGC ( ehci, "XHCI %p port %d nonsensical CLEAR_TT for %s endpoint "
+	       "%02x\n", ehci, port->address, ep->usb->name, ep->address );
+
+	return -ENOTSUP;
+}
+
 /******************************************************************************
  *
  * PCI interface
 		.enable = xhci_hub_enable,
 		.disable = xhci_hub_disable,
 		.speed = xhci_hub_speed,
+		.clear_tt = xhci_hub_clear_tt,
 	},
 };
 

src/include/ipxe/usb.h

 	 * @ret rc		Return status code
 	 */
 	int ( * speed ) ( struct usb_hub *hub, struct usb_port *port );
+	/** Clear transaction translator buffer
+	 *
+	 * @v hub		USB hub
+	 * @v port		USB port
+	 * @v ep		USB endpoint
+	 * @ret rc		Return status code
+	 */
+	int ( * clear_tt ) ( struct usb_hub *hub, struct usb_port *port,
+			     struct usb_endpoint *ep );
 };
 
 /**