greybus: tracepoints: add tracepoints for host_device tx/rx

This patch adds new tracepoint declarations to greybus_trace.h to allow for
capture of greybus host device tx and rx events. These two tracepoints
allow an observer to see the point where the hardware interface driver
performs the relevant read or write to receive or write the data it's been
given from the higher layer greybus driver.

The following two new tracepoints are declared:
- trace_gb_host_device_send
- trace_gb_host_device_recv
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/core.c

@@ -13,6 +13,9 @@
 #include "greybus.h"
 #include "greybus_trace.h"
 
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_host_device_send);
+EXPORT_TRACEPOINT_SYMBOL_GPL(gb_host_device_recv);
+
 /* Allow greybus to be disabled at boot if needed */
 static bool nogreybus;
 #ifdef MODULE

drivers/staging/greybus/greybus_trace.h

@@ -15,6 +15,7 @@
 #include <linux/tracepoint.h>
 
 struct gb_message;
+struct greybus_host_device;
 
 DECLARE_EVENT_CLASS(gb_message,
 
@@ -105,6 +106,55 @@ DEFINE_EVENT(gb_message, gb_message_cancel_incoming,
 	TP_ARGS(message)
 );
 
+DECLARE_EVENT_CLASS(gb_host_device,
+
+	TP_PROTO(struct greybus_host_device *hd, u16 intf_cport_id,
+		 size_t payload_size),
+
+	TP_ARGS(hd, intf_cport_id, payload_size),
+
+	TP_STRUCT__entry(
+		__string(name, dev_name(hd->parent))
+		__field(u16, intf_cport_id)
+		__field(size_t, payload_size)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, dev_name(hd->parent))
+		__entry->intf_cport_id = intf_cport_id;
+		__entry->payload_size = payload_size;
+	),
+
+	TP_printk("greybus:%s if_id=%04x l=%zu", __get_str(name),
+		  __entry->intf_cport_id, __entry->payload_size)
+);
+
+/*
+ * tracepoint name	greybus:gb_host_device_send
+ * description		tracepoint representing the point data are transmitted
+ * location		es1.c/es2.c:message_send
+ */
+DEFINE_EVENT(gb_host_device, gb_host_device_send,
+
+	TP_PROTO(struct greybus_host_device *hd, u16 intf_cport_id,
+		 size_t payload_size),
+
+	TP_ARGS(hd, intf_cport_id, payload_size)
+);
+
+/*
+ * tracepoint name	greybus:gb_host_device_recv
+ * description		tracepoint representing the point data are received
+ * location		es1.c/es2.c:cport_in_callback
+ */
+DEFINE_EVENT(gb_host_device, gb_host_device_recv,
+
+	TP_PROTO(struct greybus_host_device *hd, u16 intf_cport_id,
+		 size_t payload_size),
+
+	TP_ARGS(hd, intf_cport_id, payload_size)
+);
+
 #endif /* _TRACE_GREYBUS_H */
 
 /* This part must be outside protection */