xhci: trace debug statements related to ring expansion

This patch defines a new trace event, which is called xhci_dbg_ring_expansion
and belongs to the event class xhci_log_msg, and adds tracepoints that trace
the debug messages associated with the expansion of endpoint ring when there
is not enough space allocated to hold all pending TRBs.
Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

drivers/usb/host/xhci-mem.c

@@ -348,7 +348,8 @@ int xhci_ring_expansion(struct xhci_hcd *xhci, struct xhci_ring *ring,
 		return -ENOMEM;
 
 	xhci_link_rings(xhci, ring, first, last, num_segs);
-	xhci_dbg(xhci, "ring expansion succeed, now has %d segments\n",
+	xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
+			"ring expansion succeed, now has %d segments",
 			ring->num_segs);
 
 	return 0;

drivers/usb/host/xhci-ring.c

@@ -2904,8 +2904,8 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
 			return -ENOMEM;
 		}
 
-		xhci_dbg(xhci, "ERROR no room on ep ring, "
-					"try ring expansion\n");
+		xhci_dbg_trace(xhci, trace_xhci_dbg_ring_expansion,
+				"ERROR no room on ep ring, try ring expansion");
 		num_trbs_needed = num_trbs - ep_ring->num_trbs_free;
 		if (xhci_ring_expansion(xhci, ep_ring, num_trbs_needed,
 					mem_flags)) {

drivers/usb/host/xhci-trace.h

@@ -62,6 +62,11 @@ DEFINE_EVENT(xhci_log_msg, xhci_dbg_init,
 	TP_ARGS(vaf)
 );
 
+DEFINE_EVENT(xhci_log_msg, xhci_dbg_ring_expansion,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+
 DECLARE_EVENT_CLASS(xhci_log_ctx,
 	TP_PROTO(struct xhci_hcd *xhci, struct xhci_container_ctx *ctx,
 		 unsigned int ep_num),