mei: me: add io register tracing

To make debugging a bit easier we add me register
access tracing
<debugfs>/tracing/events/mei/mei_reg_{read,write}

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/Makefile

@@ -21,3 +21,6 @@ mei-me-objs += hw-me.o
 obj-$(CONFIG_INTEL_MEI_TXE) += mei-txe.o
 mei-txe-objs := pci-txe.o
 mei-txe-objs += hw-txe.o
+
+mei-$(CONFIG_EVENT_TRACING) += mei-trace.o
+CFLAGS_mei-trace.o = -I$(src)

drivers/misc/mei/hw-me.c

@@ -25,6 +25,8 @@
 #include "hw-me.h"
 #include "hw-me-regs.h"
 
+#include "mei-trace.h"
+
 /**
  * mei_me_reg_read - Reads 32bit data from the mei device
  *
@@ -86,7 +88,12 @@ static inline void mei_me_hcbww_write(struct mei_device *dev, u32 data)
  */
 static inline u32 mei_me_mecsr_read(const struct mei_device *dev)
 {
-	return mei_me_reg_read(to_me_hw(dev), ME_CSR_HA);
+	u32 reg;
+
+	reg = mei_me_reg_read(to_me_hw(dev), ME_CSR_HA);
+	trace_mei_reg_read(dev->dev, "ME_CSR_HA", ME_CSR_HA, reg);
+
+	return reg;
 }
 
 /**
@@ -98,7 +105,12 @@ static inline u32 mei_me_mecsr_read(const struct mei_device *dev)
  */
 static inline u32 mei_hcsr_read(const struct mei_device *dev)
 {
-	return mei_me_reg_read(to_me_hw(dev), H_CSR);
+	u32 reg;
+
+	reg = mei_me_reg_read(to_me_hw(dev), H_CSR);
+	trace_mei_reg_read(dev->dev, "H_CSR", H_CSR, reg);
+
+	return reg;
 }
 
 /**
@@ -109,6 +121,7 @@ static inline u32 mei_hcsr_read(const struct mei_device *dev)
  */
 static inline void mei_hcsr_write(struct mei_device *dev, u32 reg)
 {
+	trace_mei_reg_write(dev->dev, "H_CSR", H_CSR, reg);
 	mei_me_reg_write(to_me_hw(dev), H_CSR, reg);
 }
 
@@ -555,9 +568,14 @@ static int mei_me_read_slots(struct mei_device *dev, unsigned char *buffer,
 static void mei_me_pg_enter(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
-	u32 reg = mei_me_reg_read(hw, H_HPG_CSR);
+	u32 reg;
+
+	reg = mei_me_reg_read(hw, H_HPG_CSR);
+	trace_mei_reg_read(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
 
 	reg |= H_HPG_CSR_PGI;
+
+	trace_mei_reg_write(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
 	mei_me_reg_write(hw, H_HPG_CSR, reg);
 }
 
@@ -569,11 +587,16 @@ static void mei_me_pg_enter(struct mei_device *dev)
 static void mei_me_pg_exit(struct mei_device *dev)
 {
 	struct mei_me_hw *hw = to_me_hw(dev);
-	u32 reg = mei_me_reg_read(hw, H_HPG_CSR);
+	u32 reg;
+
+	reg = mei_me_reg_read(hw, H_HPG_CSR);
+	trace_mei_reg_read(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
 
 	WARN(!(reg & H_HPG_CSR_PGI), "PGI is not set\n");
 
 	reg |= H_HPG_CSR_PGIHEXR;
+
+	trace_mei_reg_write(dev->dev, "H_HPG_CSR", H_HPG_CSR, reg);
 	mei_me_reg_write(hw, H_HPG_CSR, reg);
 }
 

drivers/misc/mei/mei-trace.c

@@ -0,0 +1,25 @@
+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+#include <linux/module.h>
+
+/* sparse doesn't like tracepoint macros */
+#ifndef __CHECKER__
+#define CREATE_TRACE_POINTS
+#include "mei-trace.h"
+
+EXPORT_TRACEPOINT_SYMBOL(mei_reg_read);
+EXPORT_TRACEPOINT_SYMBOL(mei_reg_write);
+#endif /* __CHECKER__ */

drivers/misc/mei/mei-trace.h

@@ -0,0 +1,74 @@
+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#if !defined(_MEI_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
+#define _MEI_TRACE_H_
+
+#include <linux/stringify.h>
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+
+#define TRACE_SYSTEM mei
+#define TRACE_SYSTEM_STRING __stringify(TRACE_SYSTEM)
+
+TRACE_EVENT(mei_reg_read,
+	TP_PROTO(const struct device *dev, const char *reg, u32 offs, u32 val),
+	TP_ARGS(dev, reg, offs, val),
+	TP_STRUCT__entry(
+		__string(dev, dev_name(dev))
+		__field(const char *, reg)
+		__field(u32, offs)
+		__field(u32, val)
+	),
+	TP_fast_assign(
+		__assign_str(dev, dev_name(dev))
+		__entry->reg  = reg;
+		__entry->offs = offs;
+		__entry->val = val;
+	),
+	TP_printk("[%s] read %s:[%#x] = %#x",
+		  __get_str(dev), __entry->reg, __entry->offs, __entry->val)
+);
+
+TRACE_EVENT(mei_reg_write,
+	TP_PROTO(const struct device *dev, const char *reg, u32 offs, u32 val),
+	TP_ARGS(dev, reg, offs, val),
+	TP_STRUCT__entry(
+		__string(dev, dev_name(dev))
+		__field(const char *, reg)
+		__field(u32, offs)
+		__field(u32, val)
+	),
+	TP_fast_assign(
+		__assign_str(dev, dev_name(dev))
+		__entry->reg = reg;
+		__entry->offs = offs;
+		__entry->val = val;
+	),
+	TP_printk("[%s] write %s[%#x] = %#x)",
+		  __get_str(dev), __entry->reg,  __entry->offs, __entry->val)
+);
+
+#endif /* _MEI_TRACE_H_ */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_PATH .
+#define TRACE_INCLUDE_FILE mei-trace
+#include <trace/define_trace.h>