greybus: tracing: add timing traces

Bryan reports he used certain message traces to determine when time
sync messages transit the boundary between the Greybus core and the
host device.  This patch adds two trace events--one a message event
for outbound messages (because it indicates its operation and its
destination), and one host device event for incoming messages
(because message information isn't available as early as desired).
These events are being created to allow the same sort of analysis
of messages without having to store extra information for every
message trace.  (The next patch changes the information a message
trace records.)

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/connection.c

@@ -81,6 +81,8 @@ void greybus_data_rcvd(struct gb_host_device *hd, u16 cport_id,
 {
 	struct gb_connection *connection;
 
+	trace_gb_hd_in(hd);
+
 	connection = gb_connection_hd_find(hd, cport_id);
 	if (!connection) {
 		dev_err(&hd->dev,

drivers/staging/greybus/es2.c

@@ -14,6 +14,7 @@
 #include <asm/unaligned.h>
 
 #include "greybus.h"
+#include "greybus_trace.h"
 #include "kernel_ver.h"
 #include "connection.h"
 
@@ -467,6 +468,9 @@ static int message_send(struct gb_host_device *hd, u16 cport_id,
 			  message->buffer, buffer_size,
 			  cport_out_callback, message);
 	urb->transfer_flags |= URB_ZERO_PACKET;
+
+	trace_gb_message_submit(message);
+
 	retval = usb_submit_urb(urb, gfp_mask);
 	if (retval) {
 		dev_err(&udev->dev, "failed to submit out-urb: %d\n", retval);

drivers/staging/greybus/greybus_trace.h

@@ -88,6 +88,12 @@ DEFINE_MESSAGE_EVENT(gb_message_cancel_outgoing);
  */
 DEFINE_MESSAGE_EVENT(gb_message_cancel_incoming);
 
+/*
+ * Occurs in the host driver message_send() function just prior to
+ * handing off the data to be processed by hardware.
+ */
+DEFINE_MESSAGE_EVENT(gb_message_submit);
+
 #undef DEFINE_MESSAGE_EVENT
 
 DECLARE_EVENT_CLASS(gb_operation,
@@ -471,7 +477,7 @@ DEFINE_HD_EVENT(gb_hd_release);
 
 /*
  * Occurs after a new host device has been added, after the
- * connection to its SVC has * been enabled.
+ * connection to its SVC has been enabled.
  */
 DEFINE_HD_EVENT(gb_hd_add);
 
@@ -481,6 +487,13 @@ DEFINE_HD_EVENT(gb_hd_add);
  */
 DEFINE_HD_EVENT(gb_hd_del);
 
+/*
+ * Occurs when a host device has passed received data to the Greybus
+ * core, after it has been determined it is destined for a valid
+ * CPort.
+ */
+DEFINE_HD_EVENT(gb_hd_in);
+
 #undef DEFINE_HD_EVENT
 
 #endif /* _TRACE_GREYBUS_H */

drivers/staging/greybus/hd.c

@@ -13,6 +13,9 @@
 #include "greybus.h"
 #include "greybus_trace.h"
 
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_message_submit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_in);
+
 static struct ida gb_hd_bus_id_map;
 
 int gb_hd_output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,