[usb] Record USB device speed separately from current port speed

Record the speed of a USB device based on the port's speed at the time
that the device was enabled.  This allows us to remember the device's
speed even after the device has been disconnected (and so the port's
current speed has changed).

In particular, this allows us to correctly identify the transaction
translator for a low-speed or full-speed device after the device has
been disconnected.

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

src/drivers/bus/usb.c

 			     struct usb_interface_descriptor *interface,
 			     unsigned int type, unsigned int index ) {
 	struct usb_device *usb = ep->usb;
-	struct usb_port *port = usb->port;
 	struct usb_endpoint_descriptor *desc;
 	struct usb_endpoint_companion_descriptor *descx;
 	unsigned int sizes;
 	/* Calculate interval */
 	if ( ( type & USB_ENDPOINT_ATTR_TYPE_MASK ) ==
 	     USB_ENDPOINT_ATTR_INTERRUPT ) {
-		if ( port->speed >= USB_SPEED_HIGH ) {
+		if ( usb->speed >= USB_SPEED_HIGH ) {
 			/* 2^(desc->interval-1) is a microframe count */
 			interval = ( 1 << ( desc->interval - 1 ) );
 		} else {
 		       hub->name, port->address, strerror ( rc ) );
 		goto err_speed;
 	}
+	usb->speed = port->speed;
 	DBGC2 ( usb, "USB %s attached as %s-speed device\n",
-		usb->name, usb_speed_name ( port->speed ) );
+		usb->name, usb_speed_name ( usb->speed ) );
 
 	/* Open device */
 	if ( ( rc = usb->host->open ( usb ) ) != 0 ) {
 	}
 
 	/* Describe control endpoint */
-	mtu = USB_EP0_DEFAULT_MTU ( port->speed );
+	mtu = USB_EP0_DEFAULT_MTU ( usb->speed );
 	usb_endpoint_describe ( &usb->control, USB_EP0_ADDRESS,
 				USB_EP0_ATTRIBUTES, mtu, USB_EP0_BURST,
 				USB_EP0_INTERVAL );
 	       le16_to_cpu ( usb->device.product ), usb->device.class.class,
 	       usb->device.class.subclass, usb->device.class.protocol,
 	       usb_bcd ( le16_to_cpu ( usb->device.protocol ) ),
-	       usb_speed_name ( port->speed ), usb->control.mtu );
+	       usb_speed_name ( usb->speed ), usb->control.mtu );
 
 	/* Configure device */
 	if ( ( rc = usb_autoconfigure ( usb ) ) != 0 )
 	struct usb_device *parent;
 
 	/* Navigate up to root hub.  If we find a low-speed or
-	 * full-speed port with a higher-speed parent device, then
-	 * that port is the transaction translator.
+	 * full-speed device with a higher-speed parent hub, then that
+	 * device's port is the transaction translator.
 	 */
 	for ( ; ( parent = usb->port->hub->usb ) ; usb = parent ) {
-		if ( ( usb->port->speed <= USB_SPEED_FULL ) &&
-		     ( parent->port->speed > USB_SPEED_FULL ) )
+		if ( ( usb->speed <= USB_SPEED_FULL ) &&
+		     ( parent->speed > USB_SPEED_FULL ) )
 			return usb->port;
 	}
 

src/drivers/usb/ehci.c

 		chr |= EHCI_CHR_TOGGLE;
 
 	/* Determine endpoint speed */
-	if ( usb->port->speed == USB_SPEED_HIGH ) {
+	if ( usb->speed == USB_SPEED_HIGH ) {
 		chr |= EHCI_CHR_EPS_HIGH;
 	} else {
-		if ( usb->port->speed == USB_SPEED_FULL ) {
+		if ( usb->speed == USB_SPEED_FULL ) {
 			chr |= EHCI_CHR_EPS_FULL;
 		} else {
 			chr |= EHCI_CHR_EPS_LOW;

src/drivers/usb/uhci.c

 		goto err_ring_alloc;
 	endpoint->ring.mtu = ep->mtu;
 	endpoint->ring.flags = UHCI_FL_CERR_MAX;
-	if ( usb->port->speed < USB_SPEED_FULL )
+	if ( usb->speed < USB_SPEED_FULL )
 		endpoint->ring.flags |= UHCI_FL_LS;
 	endpoint->ring.control = ( UHCI_CONTROL_DEVICE ( usb->address ) |
 				   UHCI_CONTROL_ENDPOINT ( ep->address ) );

src/drivers/usb/xhci.c

 static int xhci_device_address ( struct usb_device *usb ) {
 	struct xhci_slot *slot = usb_get_hostdata ( usb );
 	struct xhci_device *xhci = slot->xhci;
-	struct usb_port *port = usb->port;
 	struct usb_port *root_port;
 	int psiv;
 	int rc;
 	slot->port = root_port->address;
 
 	/* Calculate protocol speed ID */
-	psiv = xhci_port_psiv ( xhci, slot->port, port->speed );
+	psiv = xhci_port_psiv ( xhci, slot->port, usb->speed );
 	if ( psiv < 0 ) {
 		rc = psiv;
 		return rc;

src/include/ipxe/usb.h

 	char name[32];
 	/** USB port */
 	struct usb_port *port;
+	/** Device speed */
+	unsigned int speed;
 	/** List of devices on this bus */
 	struct list_head list;
 	/** Device address, if assigned */