Allow deeper platform port directory structure

Update the top level makefile to allow platform ports to exist in
subdirectories at any level instead of one level under `plat/`. The
makefile recursively searches for all files called `platform.mk` in
all subdirectories of `plat/`. The directory containing
`platform.mk` is the platform name. Platform names must be unique
across the codebase.

Replace usage of HELP_PLATFORMS in the Makefile with PLATFORMS since
these are both used to report the same information back to the user.

Update the TSP and cert_create tool makefiles in a similar way
to support a deeper platform port directory structure.

Also add PLAT_<plat_name> as a define passed through the top level
makefile to the source files, to allow build time variation in common
platform code.

Change-Id: I213420164808c5ddb99a26144e8e3f141a7417b7

Makefile

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are met:
@@ -126,9 +126,14 @@ BL_COMMON_SOURCES	:=	common/bl_common.c			\
 BUILD_BASE		:=	./build
 BUILD_PLAT		:=	${BUILD_BASE}/${PLAT}/${BUILD_TYPE}
 
-PLATFORMS		:=	$(shell ls -I common plat/)
+PLAT_MAKEFILE		:=	platform.mk
+# Generate the platforms list by recursively searching for all directories
+# under /plat containing a PLAT_MAKEFILE. Append each platform with a `|`
+# char and strip out the final '|'.
+PLATFORMS		:=	$(shell find plat/ -name '${PLAT_MAKEFILE}' -print0 |			\
+					sed -r 's%[^\x00]*\/([^/]*)\/${PLAT_MAKEFILE}\x00%\1|%g' |	\
+					sed -r 's/\|$$//')
 SPDS			:=	$(shell ls -I none services/spd)
-HELP_PLATFORMS		:=	$(shell echo ${PLATFORMS} | sed 's/ /|/g')
 
 # Convenience function for adding build definitions
 # $(eval $(call add_define,FOO)) will have:
@@ -144,9 +149,10 @@ $(and $(patsubst 0,,$(value $(1))),$(patsubst 1,,$(value $(1))),$(error $(1) mus
 endef
 
 ifeq (${PLAT},)
-  $(error "Error: Unknown platform. Please use PLAT=<platform name> to specify the platform.")
+  $(error "Error: Unknown platform. Please use PLAT=<platform name> to specify the platform")
 endif
-ifeq ($(findstring ${PLAT},${PLATFORMS}),)
+PLAT_MAKEFILE_FULL	:=	$(shell find plat/ -wholename '*/${PLAT}/${PLAT_MAKEFILE}')
+ifeq ($(PLAT_MAKEFILE_FULL),)
   $(error "Error: Invalid platform. The following platforms are available: ${PLATFORMS}")
 endif
 
@@ -155,7 +161,7 @@ all: msg_start
 msg_start:
 	@echo "Building ${PLAT}"
 
-include plat/${PLAT}/platform.mk
+include ${PLAT_MAKEFILE_FULL}
 
 # Include the CPU specific operations makefile. By default all CPU errata
 # workarounds and CPU specifc optimisations are disabled. This can be
@@ -225,6 +231,9 @@ CFLAGS			+= 	-g
 ASFLAGS			+= 	-g -Wa,--gdwarf-2
 endif
 
+# Process PLAT flag
+$(eval $(call add_define,PLAT_${PLAT}))
+
 # Process NS_TIMER_SWITCH flag
 $(eval $(call assert_boolean,NS_TIMER_SWITCH))
 $(eval $(call add_define,NS_TIMER_SWITCH))
@@ -633,7 +642,7 @@ cscope:
 	${Q}cscope -b -q -k
 
 help:
-	@echo "usage: ${MAKE} PLAT=<${HELP_PLATFORMS}> [OPTIONS] [TARGET]"
+	@echo "usage: ${MAKE} PLAT=<${PLATFORMS}> [OPTIONS] [TARGET]"
 	@echo ""
 	@echo "PLAT is used to specify which platform you wish to build."
 	@echo "If no platform is specified, PLAT defaults to: ${DEFAULT_PLAT}"

bl32/tsp/tsp.mk

@@ -52,7 +52,7 @@ $(eval $(call add_define,TSP_INIT_ASYNC))
 # Include the platform-specific TSP Makefile
 # If no platform-specific TSP Makefile exists, it means TSP is not supported
 # on this platform.
-TSP_PLAT_MAKEFILE := plat/${PLAT}/tsp/tsp-${PLAT}.mk
+TSP_PLAT_MAKEFILE := $(shell find plat/ -wholename '*/${PLAT}/tsp/tsp-${PLAT}.mk')
 ifeq (,$(wildcard ${TSP_PLAT_MAKEFILE}))
   $(error TSP is not supported on platform ${PLAT})
 else

tools/cert_create/Makefile

@@ -47,7 +47,13 @@ CFLAGS := -Wall -std=c99
 
 # Check the platform
 ifeq (${PLAT},none)
-  $(error Error: No platform defined. Use PLAT=<platform>.)
+  $(error "Error: Unknown platform. Please use PLAT=<platform name> to specify the platform")
+endif
+PLAT_MAKEFILE		:=	platform.mk
+PLAT_INCLUDE	:=	$(shell find ../../plat/ -wholename '*/${PLAT}/${PLAT_MAKEFILE}' |	\
+				sed 's/${PLAT_MAKEFILE}/include/')
+ifeq ($(PLAT_INCLUDE),)
+  $(error "Error: Invalid platform '${PLAT}'")
 endif
 
 ifeq (${DEBUG},1)
@@ -63,7 +69,7 @@ endif
 
 # Make soft links and include from local directory otherwise wrong headers
 # could get pulled in from firmware tree.
-INC_DIR := -I ./include -I ../../plat/${PLAT}/include
+INC_DIR := -I ./include -I ${PLAT_INCLUDE}
 LIB_DIR :=
 LIB := -lssl -lcrypto