e1000e: Add e1000e trace module

Add tracepoints to the driver via a new file e1000e_trace.h and some new
trace calls added in interesting places in the driver. Add some tracing
for s0ix flows to help in a debug of shared resources with the CSME
firmware. The idea here is that tracepoints have such low performance cost
when disabled that we can leave these in the upstream driver.

Performance not affected, and this can be very useful for debugging and
adding new trace events to paths in the future.

Usage:
echo "e1000e_trace:*" > /sys/kernel/debug/tracing/set_event
echo 1 > /sys/kernel/debug/tracing/events/e1000e_trace/enable
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/e1000e/Makefile

@@ -5,6 +5,9 @@
 # Makefile for the Intel(R) PRO/1000 ethernet driver
 #
 
+ccflags-y += -I$(src)
+subdir-ccflags-y += -I$(src)
+
 obj-$(CONFIG_E1000E) += e1000e.o
 
 e1000e-objs := 82571.o ich8lan.o 80003es2lan.o \

drivers/net/ethernet/intel/e1000e/e1000e_trace.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2022, Intel Corporation. */
+/* Modeled on trace-events-sample.h */
+/* The trace subsystem name for e1000e will be "e1000e_trace".
+ *
+ * This file is named e1000e_trace.h.
+ *
+ * Since this include file's name is different from the trace
+ * subsystem name, we'll have to define TRACE_INCLUDE_FILE at the end
+ * of this file.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM e1000e_trace
+
+#if !defined(_TRACE_E1000E_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_E1000E_TRACE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(e1000e_trace_mac_register,
+	    TP_PROTO(uint32_t reg),
+	    TP_ARGS(reg),
+	    TP_STRUCT__entry(__field(uint32_t,	reg)),
+	    TP_fast_assign(__entry->reg = reg;),
+	    TP_printk("event: TraceHub e1000e mac register: 0x%08x",
+		      __entry->reg)
+);
+
+#endif
+/* This must be outside ifdef _E1000E_TRACE_H */
+/* This trace include file is not located in the .../include/trace
+ * with the kernel tracepoint definitions, because we're a loadable
+ * module.
+ */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE e1000e_trace
+
+#include <trace/define_trace.h>

drivers/net/ethernet/intel/e1000e/netdev.c

@@ -28,6 +28,8 @@
 #include <linux/suspend.h>
 
 #include "e1000.h"
+#define CREATE_TRACE_POINTS
+#include "e1000e_trace.h"
 
 char e1000e_driver_name[] = "e1000e";
 
@@ -6351,6 +6353,7 @@ static void e1000e_s0ix_entry_flow(struct e1000_adapter *adapter)
 		mac_data = er32(H2ME);
 		mac_data |= E1000_H2ME_START_DPG;
 		mac_data &= ~E1000_H2ME_EXIT_DPG;
+		trace_e1000e_trace_mac_register(mac_data);
 		ew32(H2ME, mac_data);
 	} else {
 		/* Request driver configure the device to S0ix */
@@ -6505,6 +6508,7 @@ static void e1000e_s0ix_exit_flow(struct e1000_adapter *adapter)
 		mac_data = er32(H2ME);
 		mac_data &= ~E1000_H2ME_START_DPG;
 		mac_data |= E1000_H2ME_EXIT_DPG;
+		trace_e1000e_trace_mac_register(mac_data);
 		ew32(H2ME, mac_data);
 
 		/* Poll up to 2.5 seconds for ME to unconfigure DPG.