Various minor changes on optee examples

Prefix test applications for the examples with 'optee_example_'.
Gitignore the generate test applications.
Few extra minor changes as make verbosity and source coding style.
STR_TRACE_USER_TA is deprecated.
Update README.

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
diff --git a/hello_world/Android.mk b/hello_world/Android.mk
index 5c019b3..ff7e7c1 100644
--- a/hello_world/Android.mk
+++ b/hello_world/Android.mk
@@ -13,7 +13,7 @@
 		$(OPTEE_CLIENT_EXPORT)/include \
 
 LOCAL_SHARED_LIBRARIES := libteec
-LOCAL_MODULE := tee_example_helloworld
+LOCAL_MODULE := optee_example_hello_world
 LOCAL_MODULE_TAGS := optional
 include $(BUILD_EXECUTABLE)
 
diff --git a/hello_world/host/Makefile b/hello_world/host/Makefile
index 17f14fe..a4099ef 100644
--- a/hello_world/host/Makefile
+++ b/hello_world/host/Makefile
@@ -12,7 +12,7 @@
 #Add/link other required libraries here
 LDADD += -lteec -L$(TEEC_EXPORT)/lib
 
-BINARY = optee_hello_world
+BINARY = optee_example_hello_world
 
 .PHONY: all
 all: $(BINARY)
diff --git a/hello_world/ta/hello_world_ta.c b/hello_world/ta/hello_world_ta.c
index 4aeacca..2423b30 100644
--- a/hello_world/ta/hello_world_ta.c
+++ b/hello_world/ta/hello_world_ta.c
@@ -25,12 +25,10 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#define STR_TRACE_USER_TA "HELLO_WORLD"
-
 #include <tee_internal_api.h>
 #include <tee_internal_api_extensions.h>
 
-#include "hello_world_ta.h"
+#include <hello_world_ta.h>
 
 /*
  * Called when the instance of the TA is created. This is the first call in
diff --git a/hello_world/ta/include/hello_world_ta.h b/hello_world/ta/include/hello_world_ta.h
index a25d0a4..8e40276 100644
--- a/hello_world/ta/include/hello_world_ta.h
+++ b/hello_world/ta/include/hello_world_ta.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Linaro Limited
+ * Copyright (c) 2016-2017, Linaro Limited
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -27,13 +27,17 @@
 #ifndef TA_HELLO_WORLD_H
 #define TA_HELLO_WORLD_H
 
-/* This UUID is generated with uuidgen
-   the ITU-T UUID generator at http://www.itu.int/ITU-T/asn1/uuid.html */
-#define TA_HELLO_WORLD_UUID { 0x8aaaf200, 0x2450, 0x11e4, \
+
+/*
+ * This UUID is generated with uuidgen
+ * the ITU-T UUID generator at http://www.itu.int/ITU-T/asn1/uuid.html
+ */
+#define TA_HELLO_WORLD_UUID \
+	{ 0x8aaaf200, 0x2450, 0x11e4, \
 		{ 0xab, 0xe2, 0x00, 0x02, 0xa5, 0xd5, 0xc5, 0x1b} }
 
-/* The Trusted Application Function ID(s) implemented in this TA */
-#define TA_HELLO_WORLD_CMD_INC_VALUE	0
-#define TA_HELLO_WORLD_CMD_DEC_VALUE	1
+/* The function IDs implemented in this TA */
+#define TA_HELLO_WORLD_CMD_INC_VALUE		0
+#define TA_HELLO_WORLD_CMD_DEC_VALUE		1
 
 #endif /*TA_HELLO_WORLD_H*/
diff --git a/hello_world/ta/sub.mk b/hello_world/ta/sub.mk
index db2413c..957af07 100644
--- a/hello_world/ta/sub.mk
+++ b/hello_world/ta/sub.mk
@@ -1,5 +1,4 @@
 global-incdirs-y += include
-#global-incdirs-y += ../host/include
 srcs-y += hello_world_ta.c
 
 # To remove a certain compiler flag, add a line like this
diff --git a/hello_world/ta/user_ta_header_defines.h b/hello_world/ta/user_ta_header_defines.h
index 016c402..fdfa6c4 100644
--- a/hello_world/ta/user_ta_header_defines.h
+++ b/hello_world/ta/user_ta_header_defines.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, Linaro Limited
+ * Copyright (c) 2016-2017, Linaro Limited
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -32,17 +32,27 @@
 #ifndef USER_TA_HEADER_DEFINES_H
 #define USER_TA_HEADER_DEFINES_H
 
-#include <hello_world_ta.h> /* To get the TA_HELLO_WORLD_UUID define */
+/* To get the TA UUID definition */
+#include <hello_world_ta.h>
 
-#define TA_UUID 				TA_HELLO_WORLD_UUID
+#define TA_UUID				TA_HELLO_WORLD_UUID
 
-#define TA_FLAGS				TA_FLAG_EXEC_DDR
+/*
+ * TA properties: multi-instance TA, no specific attribute
+ * TA_FLAG_EXEC_DDR is meaningless but mandated.
+ */
+#define TA_FLAGS			TA_FLAG_EXEC_DDR
+
+/* Provisioned stack size */
 #define TA_STACK_SIZE			(2 * 1024)
+
+/* Provisioned heap size for TEE_Malloc() and friends */
 #define TA_DATA_SIZE			(32 * 1024)
 
+/* Extra properties (give a version id and a string name) */
 #define TA_CURRENT_TA_EXT_PROPERTIES \
     { "gp.ta.description", USER_TA_PROP_TYPE_STRING, \
-        "Hello World TA" }, \
+        "Example of OP-TEE Hello World Trusted Application" }, \
     { "gp.ta.version", USER_TA_PROP_TYPE_U32, &(const uint32_t){ 0x0010 } }
 
-#endif /*USER_TA_HEADER_DEFINES_H*/
+#endif /* USER_TA_HEADER_DEFINES_H */