From cc80961b5fb8a4ce6130d16674efe096dcf5c9b8 Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Fri, 4 May 2018 15:43:41 +0200
Subject: [PATCH] make: allow feature based blacklisting (FEATURES_BLACKLIST)

---
 Makefile.features            | 10 ++++++++--
 Makefile.include             |  3 +++
 makefiles/info-global.inc.mk |  2 ++
 makefiles/info.inc.mk        |  2 ++
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/Makefile.features b/Makefile.features
index 4cdf39e56e..1e6de19cf7 100644
--- a/Makefile.features
+++ b/Makefile.features
@@ -22,9 +22,11 @@ endif
 # Resolve FEATURES_ variables
 # Their value will only be complete after resolving dependencies
 
-# Features that are required by the application but not provided by the BSP
+# Features that are required by the application but not provided by the BSP and
+# features that are used but blacklisted (prepended with "!").
 # Having features missing may case the build to fail.
-FEATURES_MISSING = $(sort $(filter-out $(FEATURES_PROVIDED),$(FEATURES_REQUIRED)))
+FEATURES_MISSING = $(sort $(filter-out $(FEATURES_PROVIDED),$(FEATURES_REQUIRED)) \
+                     $(call _features_used_blacklisted))
 
 # Features that are only optional and not required at the same time.
 # The policy is to by default use by features if they are provided by the BSP.
@@ -47,3 +49,7 @@ _features_conflicting = $(if $(call _features_used_conflicting,$(subst :, ,$1)),
 #   $1: list of features that conflict together
 #   Return non empty on error
 _features_used_conflicting = $(filter $(words $1),$(words $(filter $(FEATURES_USED),$1)))
+
+# Return features that are used but blacklisted as
+# "!<feature>" ("not feature")
+_features_used_blacklisted = $(addprefix !,$(sort $(filter $(FEATURES_USED), $(FEATURES_BLACKLIST))))
diff --git a/Makefile.include b/Makefile.include
index 4acf053677..da39ecaadf 100644
--- a/Makefile.include
+++ b/Makefile.include
@@ -732,6 +732,9 @@ ifneq (, $(filter all flash, $(if $(MAKECMDGOALS), $(MAKECMDGOALS), all)))
     EXPECT_ERRORS := 1
   endif
 
+  # turn provided but blacklisted features into required "!<feature>"
+  FEATURES_REQUIRED += $(addprefix !,$(sort $(filter $(FEATURES_PROVIDED), $(FEATURES_BLACKLIST))))
+
   # Test if all feature requirements were met by the selected board.
   ifneq (,$(FEATURES_MISSING))
     $(shell $(COLOR_ECHO) "$(COLOR_RED)There are unsatisfied feature requirements:$(COLOR_RESET)"\
diff --git a/makefiles/info-global.inc.mk b/makefiles/info-global.inc.mk
index b3a97394a2..b79475125a 100644
--- a/makefiles/info-global.inc.mk
+++ b/makefiles/info-global.inc.mk
@@ -9,6 +9,7 @@ FEATURES_CONFLICT_GLOBAL := $(FEATURES_CONFLICT)
 FEATURES_CONFLICT_MSG_GLOBAL := $(FEATURES_MSG_CONFLICT)
 DISABLE_MODULE_GLOBAL := $(DISABLE_MODULE)
 DEFAULT_MODULE_GLOBAL := $(DEFAULT_MODULE)
+FEATURES_BLACKLIST_GLOBAL := $(FEATURES_BLACKLIST)
 
 define board_missing_features
   BOARD             := $(1)
@@ -20,6 +21,7 @@ define board_missing_features
   FEATURES_OPTIONAL := $(FEATURES_OPTIONAL_GLOBAL)
   FEATURES_CONFLICT := $(FEATURES_CONFLICT_GLOBAL)
   FEATURES_CONFLICT_MSG := $(FEATURES_CONFLICT_MSG_GLOBAL)
+  FEATURES_BLACKLIST:= $(FEATURES_BLACKLIST_GLOBAL)
 
   # Remove board specific variables set by Makefile.features/Makefile.dep
   FEATURES_PROVIDED :=
diff --git a/makefiles/info.inc.mk b/makefiles/info.inc.mk
index 47f0cc7744..0ec6d69624 100644
--- a/makefiles/info.inc.mk
+++ b/makefiles/info.inc.mk
@@ -60,6 +60,8 @@ info-build:
 	@echo '         $(or $(sort $(FEATURES_PROVIDED)), -none-)'
 	@echo 'FEATURES_MISSING (only non optional features):'
 	@echo '         $(or $(FEATURES_MISSING), -none-)'
+	@echo 'FEATURES_BLACKLIST (blacklisted features):'
+	@echo '         $(or $(sort $(FEATURES_BLACKLIST)), -none-)'
 	@echo ''
 	@echo 'FEATURES_CONFLICT:     $(FEATURES_CONFLICT)'
 	@echo 'FEATURES_CONFLICT_MSG: $(FEATURES_CONFLICT_MSG)'