trace, scm: trace scm calls

Create a scm group to enable profiling time spent in a scm call.
This will help determine which scm call is spending how much time in
a higher execution level.
To enable "echo 1 > /sys/kernel/debug/tracing/events/scm/enable".
It is disabled by default. If enabled, traces can be found in
Ftrace logs.

Ftrace Output Example:
PROCESS             CPU    TIME        SCM ID, X0, Number of args, args[0-2], X5, return values [0-2]
kworker/u8:4-329   [002]   128.201129: scm_call_start: func id=0x42000904 (args: 0x6, 0x2, 0x200000000, 0x65b8000000019, 0x142e0f000)
kworker/u8:4-329   [002]   128.201383: scm_call_end: ret: 0, 0, 0x4a07e00000001
kworker/u8:4-329   [002]   128.201464: scm_call_start: func id=0x42000904 (args: 0x6, 0x3, 0x1312d0000000000, 0x17900000000, 0x142e0f000)
kworker/u8:4-329   [002]   128.201542: scm_call_end: ret: 0x1bf03dddddd, 0x2f72656b726f776b, 0x343a32

CRs-Fixed: 969770
Change-Id: I4e5aaff796dbc9457c55fa529114dcb57780b7ec
Signed-off-by: Sanrio Alvares <salvares@codeaurora.org>

drivers/soc/qcom/scm.c

@@ -24,6 +24,9 @@
 
 #include <soc/qcom/scm.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/scm.h>
+
 #define SCM_ENOMEM		-5
 #define SCM_EOPNOTSUPP		-4
 #define SCM_EINVAL_ADDR		-3
@@ -658,6 +661,8 @@ int scm_call2(u32 fn_id, struct scm_desc *desc)
 			x0, desc->arginfo, desc->args[0], desc->args[1],
 			desc->args[2], desc->x5);
 
+		trace_scm_call_start(x0, desc);
+
 		if (scm_version == SCM_ARMV8_64)
 			ret = __scm_call_armv8_64(x0, desc->arginfo,
 						  desc->args[0], desc->args[1],
@@ -671,6 +676,8 @@ int scm_call2(u32 fn_id, struct scm_desc *desc)
 						  &desc->ret[0], &desc->ret[1],
 						  &desc->ret[2]);
 
+		trace_scm_call_end(desc);
+
 		if (SCM_SVC_ID(fn_id) == SCM_SVC_LMH)
 			mutex_unlock(&scm_lmh_lock);
 

include/trace/events/scm.h

@@ -0,0 +1,68 @@
+/* Copyright (c) 2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM scm
+
+#if !defined(_TRACE_SCM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SCM_H
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+#include <soc/qcom/scm.h>
+
+TRACE_EVENT(scm_call_start,
+
+	TP_PROTO(u64 x0, struct scm_desc *p),
+
+	TP_ARGS(x0, p),
+
+	TP_STRUCT__entry(
+		__field(u64, x0)
+		__field(u32, arginfo)
+		__array(u64, args, MAX_SCM_ARGS)
+		__field(u64, x5)
+	),
+
+	TP_fast_assign(
+		__entry->x0		= x0;
+		__entry->arginfo	= p->arginfo;
+		memcpy(__entry->args, p->args, MAX_SCM_ARGS);
+		__entry->x5		= p->x5;
+	),
+
+	TP_printk("func id=%#llx (args: %#x, %#llx, %#llx, %#llx, %#llx)",
+		__entry->x0, __entry->arginfo, __entry->args[0],
+		__entry->args[1], __entry->args[2], __entry->x5)
+);
+
+
+TRACE_EVENT(scm_call_end,
+
+	TP_PROTO(struct scm_desc *p),
+
+	TP_ARGS(p),
+
+	TP_STRUCT__entry(
+		__array(u64, ret, MAX_SCM_RETS)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->ret, p->ret, MAX_SCM_RETS);
+	),
+
+	TP_printk("ret: %#llx, %#llx, %#llx",
+		__entry->ret[0], __entry->ret[1], __entry->ret[2])
+);
+#endif /* _TRACE_SCM_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>