[PATCH] USB: ehci-hcd, scheduler handles TT collisions (3/3)

[USB] ehci-hcd detects microframe transaction scheduling collisions

This detects TT schedule collisions for split periodic transactions
on USB 2.0 hubs, handling both isochronous and interrupt transfers
but not supporting the "wrap around to the next frame" modes for
either transfer type.

The ISO scheduler is modified to use that support for full speed
transfers ... though nothing will yet ask it to do that.

It also tracks schedule depth, to help avoid accepting ISO URBs
which need more time than currently remains unscheduled.

drivers/usb/host/ehci.h

@@ -418,6 +418,7 @@ struct ehci_iso_stream {
 	u32			refcount;
 	u8			bEndpointAddress;
 	u8			highspeed;
+	u16			depth;		/* depth in uframes */
 	struct list_head	td_list;	/* queued itds/sitds */
 	struct list_head	free_list;	/* list of unused itds/sitds */
 	struct usb_device	*udev;
@@ -426,6 +427,7 @@ struct ehci_iso_stream {
 	unsigned long		start;		/* jiffies */
 	unsigned long		rescheduled;
 	int			next_uframe;
+	u32			splits;
 
 	/* the rest is derived from the endpoint descriptor,
 	 * trusting urb->interval == f(epdesc->bInterval) and
@@ -434,6 +436,7 @@ struct ehci_iso_stream {
 	u8			interval;
 	u8			usecs, c_usecs;
 	u16			maxp;
+	u16			raw_mask;
 	unsigned		bandwidth;
 
 	/* This is used to initialize iTD's hw_bufp fields */
@@ -441,7 +444,8 @@ struct ehci_iso_stream {
 	u32			buf1;		
 	u32			buf2;
 
-	/* ... sITD won't use buf[012], and needs TT access ... */
+	/* this is used to initialize sITD's tt info */
+	u32			address;
 };
 
 /*-------------------------------------------------------------------------*/