MIPS: Allow platform to specify multiple its.S files

In preparation for splitting arch/mips/generic/vmlinux.its.S into
multiple files such that it doesn't become a conflict magnet as boards
are added, allow platforms to specify a list of image tree source files
which will be concatenated to form the final source used to build the
image tree.

Signed-off-by: Paul Burton <[e-mail]>
Cc: [e-mail]
Patchwork: https://patchwork.linux-mips.org/patch/16938/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/Makefile

···
 
 bootvars-y	= VMLINUX_LOAD_ADDRESS=$(load-y) \
 		  VMLINUX_ENTRY_ADDRESS=$(entry-y) \
-		  PLATFORM="$(platform-y)"
+		  PLATFORM="$(platform-y)" \
+		  ITS_INPUTS="$(its-y)"
 ifdef CONFIG_32BIT
 bootvars-y	+= ADDR_BITS=32
 endif

arch/mips/boot/Makefile

···
 	itb_addr_cells = 2
 endif
 
+quiet_cmd_its_cat = CAT     $@
+      cmd_its_cat = cat $^ >$@
+
+$(obj)/vmlinux.its.S: $(addprefix $(srctree)/arch/mips/$(PLATFORM)/,$(ITS_INPUTS))
+	$(call if_changed,its_cat)
+
 quiet_cmd_cpp_its_S = ITS     $@
       cmd_cpp_its_S = $(CPP) $(cpp_flags) -P -C -o $@ $< \
 		        -DKERNEL_NAME="\"Linux $(KERNELRELEASE)\"" \
···
 			-DADDR_BITS=$(ADDR_BITS) \
 			-DADDR_CELLS=$(itb_addr_cells)
 
-$(obj)/vmlinux.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
+$(obj)/vmlinux.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,none,vmlinux.bin)
 
-$(obj)/vmlinux.gz.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
+$(obj)/vmlinux.gz.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,gzip,vmlinux.bin.gz)
 
-$(obj)/vmlinux.bz2.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX)  FORCE
+$(obj)/vmlinux.bz2.its: $(obj)/vmlinux.its.S $(VMLINUX)  FORCE
 	$(call if_changed_dep,cpp_its_S,bzip2,vmlinux.bin.bz2)
 
-$(obj)/vmlinux.lzma.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
+$(obj)/vmlinux.lzma.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,lzma,vmlinux.bin.lzma)
 
-$(obj)/vmlinux.lzo.its: $(srctree)/arch/mips/$(PLATFORM)/vmlinux.its.S $(VMLINUX) FORCE
+$(obj)/vmlinux.lzo.its: $(obj)/vmlinux.its.S $(VMLINUX) FORCE
 	$(call if_changed_dep,cpp_its_S,lzo,vmlinux.bin.lzo)
 
 quiet_cmd_itb-image = ITB     $@

arch/mips/generic/Platform

···
 cflags-$(CONFIG_MIPS_GENERIC)	+= -I$(srctree)/arch/mips/include/asm/mach-generic
 load-$(CONFIG_MIPS_GENERIC)	+= 0xffffffff80100000
 all-$(CONFIG_MIPS_GENERIC)	:= vmlinux.gz.itb
+
+its-y					:= vmlinux.its.S