Makefile: Support totally quiet output with -s

"-s" is a command line option to the make tool, to suppress normal output,
something to the effect of prepending every line with '@' in the Makefile.
However with our V={0|1} support, we now print the shortened command line
output in any case (even with V=1, in addition to the long line!).
Normally -s helps to not miss non-fatal warnings, which tend to scroll out
of the window easily.

Introduce a new Makefile variable ECHO, to control the shortened output.
We only set it in the (current default) V=0 case, and replace every
occurence of "@echo" with that variable.
When the user specifies "-s", we set ECHO to some magic string which
changes the output line into a comment, so the output is suppressed.

Beside suppressing every output for "-s", we also avoid the redundant
short output when compiling with V=1.

This changes the output to:
==========
$ make -s PLAT=.... bl31

Built build/.../release/bl31.bin

==========
$ make PLAT=.... bl31
...
  CC      lib/libc/strncmp.c
  CC      lib/libc/strnlen.c
...
==========
$ make V=1 PLAT=.... bl31
...
gcc -DDEBUG=0 .... -o build/.../release/libc/strncmp.o
gcc -DDEBUG=0 .... -o build/.../release/libc/strnlen.o
...
==========

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

Makefile

@@ -74,11 +74,19 @@ CHECK_PATHS		:=	${ROOT_DIRS_TO_CHECK}			\
 # Verbose flag
 ifeq (${V},0)
         Q:=@
+        ECHO:=@echo
         CHECKCODE_ARGS	+=	--no-summary --terse
 else
         Q:=
+        ECHO:=@\#
 endif
-export Q
+
+ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
+        Q:=@
+        ECHO:=@\#
+endif
+
+export Q ECHO
 
 # Process Debug flag
 $(eval $(call add_define,DEBUG))

make_helpers/build_macros.mk

@@ -177,7 +177,7 @@ endef
 # GZIP
 define GZIP_RULE
 $(1): $(2)
-	@echo "  GZIP    $$@"
+	$(ECHO) "  GZIP    $$@"
 	$(Q)gzip -n -f -9 $$< --stdout > $$@
 endef
 
@@ -199,7 +199,7 @@ $(eval OBJ := $(1)/$(patsubst %.c,%.o,$(notdir $(2))))
 $(eval DEP := $(patsubst %.o,%.d,$(OBJ)))
 
 $(OBJ): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | lib$(3)_dirs
-	@echo "  CC      $$<"
+	$$(ECHO) "  CC      $$<"
 	$$(Q)$$(CC) $$(TF_CFLAGS) $$(CFLAGS) $(MAKE_DEP) -c $$< -o $$@
 
 -include $(DEP)
@@ -218,7 +218,7 @@ $(eval DEP := $(patsubst %.o,%.d,$(OBJ)))
 $(eval IMAGE := IMAGE_BL$(call uppercase,$(3)))
 
 $(OBJ): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | bl$(3)_dirs
-	@echo "  CC      $$<"
+	$$(ECHO) "  CC      $$<"
 	$$(Q)$$(CC) $$(TF_CFLAGS) $$(CFLAGS) -D$(IMAGE) $(MAKE_DEP) -c $$< -o $$@
 
 -include $(DEP)
@@ -237,7 +237,7 @@ $(eval DEP := $(patsubst %.o,%.d,$(OBJ)))
 $(eval IMAGE := IMAGE_BL$(call uppercase,$(3)))
 
 $(OBJ): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | bl$(3)_dirs
-	@echo "  AS      $$<"
+	$$(ECHO) "  AS      $$<"
 	$$(Q)$$(AS) $$(ASFLAGS) -D$(IMAGE) $(MAKE_DEP) -c $$< -o $$@
 
 -include $(DEP)
@@ -255,7 +255,7 @@ $(eval DEP := $(1).d)
 $(eval IMAGE := IMAGE_BL$(call uppercase,$(3)))
 
 $(1): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | bl$(3)_dirs
-	@echo "  PP      $$<"
+	$$(ECHO) "  PP      $$<"
 	$$(Q)$$(CPP) $$(CPPFLAGS) -P -D__ASSEMBLY__ -D__LINKER__ $(MAKE_DEP) -D$(IMAGE) -o $$@ $$<
 
 -include $(DEP)
@@ -344,7 +344,7 @@ endif
 all: ${LIB_DIR}/lib$(1).a
 
 ${LIB_DIR}/lib$(1).a: $(OBJS)
-	@echo "  AR      $$@"
+	$$(ECHO) "  AR      $$@"
 	$$(Q)$$(AR) cr $$@ $$?
 endef
 
@@ -392,7 +392,7 @@ $(ELF): romlib.bin
 endif
 
 $(ELF): $(OBJS) $(LINKERFILE) | bl$(1)_dirs libraries $(BL_LIBS)
-	@echo "  LD      $$@"
+	$$(ECHO) "  LD      $$@"
 ifdef MAKE_BUILD_STRINGS
 	$(call MAKE_BUILD_STRINGS, $(BUILD_DIR)/build_message.o)
 else
@@ -405,11 +405,11 @@ endif
 		$(OBJS) $(LDPATHS) $(LDLIBS) $(BL_LIBS)
 
 $(DUMP): $(ELF)
-	@echo "  OD      $$@"
+	$${ECHO} "  OD      $$@"
 	$${Q}$${OD} -dx $$< > $$@
 
 $(BIN): $(ELF)
-	@echo "  BIN     $$@"
+	$${ECHO} "  BIN     $$@"
 	$$(Q)$$(OC) -O binary $$< $$@
 	@${ECHO_BLANK_LINE}
 	@echo "Built $$@ successfully"
@@ -461,10 +461,10 @@ $(eval DTSDEP := $(patsubst %.dtb,%.o.d,$(DOBJ)))
 $(eval DTBDEP := $(patsubst %.dtb,%.d,$(DOBJ)))
 
 $(DOBJ): $(2) $(filter-out %.d,$(MAKEFILE_LIST)) | fdt_dirs
-	@echo "  CPP     $$<"
+	$${ECHO} "  CPP     $$<"
 	$(eval DTBS       := $(addprefix $(1)/,$(call SOURCES_TO_DTBS,$(2))))
 	$$(Q)$$(CPP) $$(CPPFLAGS) -x assembler-with-cpp -MT $(DTBS) -MMD -MF $(DTSDEP) -o $(DPRE) $$<
-	@echo "  DTC     $$<"
+	$${ECHO} "  DTC     $$<"
 	$$(Q)$$(DTC) $$(DTC_FLAGS) -i fdts -d $(DTBDEP) -o $$@ $(DPRE)
 
 -include $(DTBDEP)