[usb] Parse endpoint descriptor bInterval field

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

src/drivers/bus/usb.c

 			     struct usb_configuration_descriptor *config,
 			     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;
 	unsigned int burst;
+	unsigned int interval;
 	size_t mtu;
 
 	/* Locate endpoint descriptor */
 	mtu = USB_ENDPOINT_MTU ( sizes );
 	burst = ( descx ? descx->burst : USB_ENDPOINT_BURST ( sizes ) );
 
+	/* Calculate interval */
+	if ( type == USB_INTERRUPT ) {
+		if ( port->speed >= USB_SPEED_HIGH ) {
+			/* 2^(desc->interval-1) is a microframe count */
+			interval = ( 1 << ( desc->interval - 1 ) );
+		} else {
+			/* desc->interval is a (whole) frame count */
+			interval = ( desc->interval << 3 );
+		}
+	} else {
+		/* desc->interval is a microframe count */
+		interval = desc->interval;
+	}
+
 	/* Describe endpoint */
 	usb_endpoint_describe ( ep, desc->endpoint, desc->attributes,
-				mtu, burst );
+				mtu, burst, interval );
 	return 0;
 }
 
 	}
 	ep->open = 1;
 
-	DBGC2 ( usb, "USB %s %s opened with MTU %zd (burst %d)\n", usb->name,
-		usb_endpoint_name ( ep->address ), ep->mtu, ep->burst );
+	DBGC2 ( usb, "USB %s %s opened with MTU %zd, burst %d, interval %d\n",
+		usb->name, usb_endpoint_name ( ep->address ), ep->mtu,
+		ep->burst, ep->interval );
 	return 0;
 
 	ep->open = 0;
 	/* Describe control endpoint */
 	mtu = USB_EP0_DEFAULT_MTU ( port->speed );
 	usb_endpoint_describe ( &usb->control, USB_EP0_ADDRESS,
-				USB_EP0_ATTRIBUTES, mtu, USB_EP0_BURST );
+				USB_EP0_ATTRIBUTES, mtu, USB_EP0_BURST,
+				USB_EP0_INTERVAL );
 
 	/* Open control endpoint */
 	if ( ( rc = usb_endpoint_open ( &usb->control ) ) != 0 )

src/drivers/usb/xhci.c

 
 	/* Populate endpoint context */
 	ep_ctx = ( input + xhci_input_context_offset ( xhci, endpoint->ctx ) );
+	ep_ctx->interval = endpoint->interval;
 	ep_ctx->type = endpoint->type;
 	ep_ctx->burst = endpoint->ep->burst;
 	ep_ctx->mtu = cpu_to_le16 ( endpoint->ep->mtu );
 	struct xhci_endpoint *endpoint;
 	unsigned int ctx;
 	unsigned int type;
+	unsigned int interval;
 	int rc;
 
 	/* Calculate context index */
 	if ( ep->address & USB_DIR_IN )
 		type |= XHCI_EP_TYPE_IN;
 
+	/* Calculate interval */
+	if ( type & XHCI_EP_TYPE_PERIODIC ) {
+		interval = ( fls ( ep->interval ) - 1 );
+	} else {
+		interval = ep->interval;
+	}
+
 	/* Allocate and initialise structure */
 	endpoint = zalloc ( sizeof ( *endpoint ) );
 	if ( ! endpoint ) {
 	endpoint->ep = ep;
 	endpoint->ctx = ctx;
 	endpoint->type = type;
+	endpoint->interval = interval;
 	endpoint->context = ( ( ( void * ) slot->context ) +
 			      xhci_device_context_offset ( xhci, ctx ) );
 

src/drivers/usb/xhci.h

 /** Input endpoint type */
 #define XHCI_EP_TYPE_IN XHCI_EP_TYPE ( 4 )
 
+/** Periodic endpoint type */
+#define XHCI_EP_TYPE_PERIODIC XHCI_EP_TYPE ( 1 )
+
 /** Endpoint dequeue cycle state */
 #define XHCI_EP_DCS 0x00000001UL
 
 	unsigned int ctx;
 	/** Endpoint type */
 	unsigned int type;
+	/** Endpoint interval */
+	unsigned int interval;
 	/** Endpoint context */
 	struct xhci_endpoint_context *context;
 	/** Transfer ring */

src/include/ipxe/usb.h

 	size_t mtu;
 	/** Maximum burst size */
 	unsigned int burst;
+	/** Interval (in microframes) */
+	unsigned int interval;
 
 	/** Endpoint is open */
 	int open;
 /** Control endpoint maximum burst size */
 #define USB_EP0_BURST 0
 
+/** Control endpoint interval */
+#define USB_EP0_INTERVAL 0
+
 /** Maximum endpoint number */
 #define USB_ENDPOINT_MAX 0x0f
 
  * @v attributes	Attributes
  * @v mtu		Maximum packet size
  * @v burst		Maximum burst size
+ * @v interval		Interval (in microframes)
  */
 static inline __attribute__ (( always_inline )) void
 usb_endpoint_describe ( struct usb_endpoint *ep, unsigned int address,
 			unsigned int attributes, size_t mtu,
-			unsigned int burst ) {
+			unsigned int burst, unsigned int interval ) {
 
 	ep->address = address;
 	ep->attributes = attributes;
 	ep->mtu = mtu;
 	ep->burst = burst;
+	ep->interval = interval;
 }
 
 /**