target/; xtensa support

Part of #163.

Signed-off-by: Maxim Grigoriev <maxim2405@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

target/xtensa/patch.in

@@ -0,0 +1,33 @@
+ifneq ($(filter xtensa%,$(ARCH)),)
+#############################################################
+#
+#  Xtensa processor architecture (including Diamond Standard cores)
+#
+#############################################################
+
+#  The following defines a function to be used like this:
+#	$(call XTENSA_PATCH, <module>, <patchdir>, <relative dir list...>)
+#  which returns the first overlay patch file for <module> found
+#  in the list of directories <relative dir list...> which are
+#  relative to <patchdir> (itself either absolute or relative to the
+#  current directory).  The returned filename is relative to <patchdir>.
+#  For example:
+#	$(call XTENSA_PATCH, binutils, some/dir/path, . ..)
+#  (no commas between directory paths in the list).
+#
+#  A selected overlay patch must exist ("fsf" means no specific
+#  overlay is selected).  So the function emits a Makefile error
+#  if a selected patch file is not found.
+
+XTENSA_CORENAME:=$(strip $(subst ",,$(BR2_xtensa_core_name)))
+ifeq ($(XTENSA_CORENAME),fsf)
+XTENSA_PATCH =
+else
+XTENSA_PATCH_SUFFIX = $(1)-xtensa_$(XTENSA_CORENAME).tgz
+XTENSA_PATCH_FILE = $(firstword $(wildcard $(patsubst %,$(2)/%/*$(XTENSA_PATCH_SUFFIX),$(3))))
+# FULLPATH = $(if $(filter /%,$(1)),$(1),$(PWD)/$(1))
+XTENSA_PATCH = $(if $(XTENSA_PATCH_FILE),$(patsubst $(2)/%,%,$(XTENSA_PATCH_FILE)),\
+	$(error Missing $(1) patch for Xtensa $(XTENSA_CORENAME) processor (*$(XTENSA_PATCH_SUFFIX) in $(addprefix $(2)/,$(3)))))
+endif
+
+endif