xhci: add traces for debug messages in xhci_address_device()

This patch declares an event class for trace events that
trace messages with variadic arguments, called xhci_log_msg,
and defines a trace event for tracing the debug messages in
xhci_address_device() function, called xhci_dbg_address.

In order to implement this type of trace events, a wrapper function,
called xhci_dbg_trace(), was created that records the format string
and variadic arguments into a va_format structure which is passed as
argument to the tracepoints of the class xhci_log_msg.

All the xhci_dbg() calls in xhci_address_device() are replaced
with calls to xhci_dbg_trace(). The functionality of xhci_dbg()
log messages was not removed though, but it is placed inside
xhci_dbg_trace().

This trace event aims to give the ability to the user or the
developper to isolate and trace the debug messages generated
when an Address Device Command is issued to xHC.

Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-trace.h b/drivers/usb/host/xhci-trace.h
new file mode 100644
index 000000000000..432aa675966c
--- /dev/null
+++ b/drivers/usb/host/xhci-trace.h
@@ -0,0 +1,49 @@
+/*
+ * xHCI host controller driver
+ *
+ * Copyright (C) 2013 Xenia Ragiadakou
+ *
+ * Author: Xenia Ragiadakou
+ * Email : burzalodowa@gmail.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM xhci-hcd
+
+#if !defined(__XHCI_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define __XHCI_TRACE_H
+
+#include <linux/tracepoint.h>
+
+#define XHCI_MSG_MAX	500
+
+DECLARE_EVENT_CLASS(xhci_log_msg,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf),
+	TP_STRUCT__entry(__dynamic_array(char, msg, XHCI_MSG_MAX)),
+	TP_fast_assign(
+		vsnprintf(__get_str(msg), XHCI_MSG_MAX, vaf->fmt, *vaf->va);
+	),
+	TP_printk("%s", __get_str(msg))
+);
+
+DEFINE_EVENT(xhci_log_msg, xhci_dbg_address,
+	TP_PROTO(struct va_format *vaf),
+	TP_ARGS(vaf)
+);
+
+#endif /* __XHCI_TRACE_H */
+
+/* this part must be outside header guard */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE xhci-trace
+
+#include <trace/define_trace.h>