Add preprocessing capabilities to the cbfs-files mechanism

It's now possible to generate files that are about to be added to
CBFS by specifying "sourcefile:method" as real file name.

This makes the build system use the cbfs-files-preprocessor-$(method)
function to create a file from sourcefile. That generated file is
then added to CBFS.

The first method to be defined is "nvramtool". It expects a plain text
specification of the CMOS configuration and emits the binary format
suitable for cmos.default.

Change-Id: I33a142718fc7238eaf5317b0ed62b4726d9b48f2
Signed-off-by: Patrick Georgi <Patrick.Georgi@secunet.com>
Reviewed-on: http://review.coreboot.org/847
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/Makefile.inc b/Makefile.inc
index 470077e..81d40df 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -79,12 +79,26 @@
 endef
 
 #######################################################################
+# Parse plaintext cmos defaults into binary format
+# arg1: source file
+# arg2: binary file name
+cbfs-files-processor-nvramtool= \
+	$(eval $(2): $(1) $(src)/mainboard/$(MAINBOARDDIR)/cmos.layout | $(objutil)/nvramtool/nvramtool ; \
+		printf "    CREATE     $(2) (from $(1))\n"; $(objutil)/nvramtool/nvramtool -y $(src)/mainboard/$(MAINBOARDDIR)/cmos.layout -D $(2).tmp -p $(1) && mv $(2).tmp $(2))
+
+#######################################################################
 # Add handler for arbitrary files in CBFS
 $(call add-special-class,cbfs-files)
 cbfs-files-handler= \
+		$(eval tmp-cbfs-method:=$(word 2, $(subst :, ,$($(2)-file)))) \
+		$(eval $(2)-file:=$(word 1, $(subst :, ,$($(2)-file)))) \
 		$(if $(wildcard $(1)$($(2)-file)), \
 			$(eval tmp-cbfs-file:= $(wildcard $(1)$($(2)-file))), \
 			$(eval tmp-cbfs-file:= $($(2)-file))) \
+		$(if $(tmp-cbfs-method), \
+			$(eval tmp-old-cbfs-file:=$(tmp-cbfs-file)) \
+			$(eval tmp-cbfs-file:=$(shell mktemp $(obj)/mainboard/$(MAINBOARDDIR)/cbfs-file.XXXXXX).out) \
+			$(call cbfs-files-processor-$(tmp-cbfs-method),$(tmp-old-cbfs-file),$(tmp-cbfs-file))) \
 		$(eval cbfs-files += $(tmp-cbfs-file)|$(2)|$($(2)-type)|$($(2)-position)) \
 		$(eval $(2)-name:=) \
 		$(eval $(2)-type:=) \