linux/firmware/Makefile

#
# kbuild file for firmware/
#

# Create $(fwabs) from $(CONFIG_EXTRA_FIRMWARE_DIR) -- if it doesn't have a
# leading /, it's relative to $(srctree).
fwdir := $(subst ",,$(CONFIG_EXTRA_FIRMWARE_DIR))
fwabs := $(addprefix $(srctree)/,$(filter-out /%,$(fwdir)))$(filter /%,$(fwdir))

fw-external-y := $(subst ",,$(CONFIG_EXTRA_FIRMWARE))

# If CONFIG_FIRMWARE_IN_KERNEL is not set, then don't include any firmware
ifneq ($(CONFIG_FIRMWARE_IN_KERNEL),y)
fw-shipped-y :=
endif

firmware-y    := $(fw-external-y) $(fw-shipped-y)
firmware-dirs := $(sort $(patsubst %,$(objtree)/$(obj)/%/,$(dir $(firmware-y) $(fw-shipped-))))

quiet_cmd_mkdir = MKDIR   $(patsubst $(objtree)/%,%,$@)
      cmd_mkdir = mkdir -p $@

quiet_cmd_ihex  = IHEX    $@
      cmd_ihex  = $(OBJCOPY) -Iihex -Obinary $< $@

quiet_cmd_fwbin = MK_FW   $@
      cmd_fwbin = FWNAME="$(patsubst firmware/%.gen.S,%,$@)";		     \
		  FWSTR="$(subst /,_,$(subst .,_,$(subst -,_,$(patsubst	     \
				firmware/%.gen.S,%,$@))))";		     \
		  ASM_WORD=$(if $(CONFIG_64BIT),.quad,.long);		     \
		  ASM_ALIGN=$(if $(CONFIG_64BIT),3,2);			     \
		  PROGBITS=$(if $(CONFIG_ARM),%,@)progbits;		     \
		  echo "/* Generated by firmware/Makefile */"		> $@;\
		  echo "    .section .rodata"				>>$@;\
		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
		  echo "_fw_$${FWSTR}_bin:"				>>$@;\
		  echo "    .incbin \"$(2)\""				>>$@;\
		  echo "_fw_end:"					>>$@;\
		  echo "   .section .rodata.str,\"aMS\",$${PROGBITS},1"	>>$@;\
		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
		  echo "_fw_$${FWSTR}_name:"				>>$@;\
		  echo "    .string \"$$FWNAME\""			>>$@;\
		  echo "    .section .builtin_fw,\"a\",$${PROGBITS}"	>>$@;\
		  echo "    .p2align $${ASM_ALIGN}"			>>$@;\
		  echo "    $${ASM_WORD} _fw_$${FWSTR}_name"		>>$@;\
		  echo "    $${ASM_WORD} _fw_$${FWSTR}_bin"		>>$@;\
		  echo "    $${ASM_WORD} _fw_end - _fw_$${FWSTR}_bin"	>>$@;

# One of these files will change, or come into existence, whenever
# the configuration changes between 32-bit and 64-bit. The .S files
# need to change when that happens.
wordsize_deps := $(wildcard include/config/64bit.h include/config/32bit.h \
		include/config/ppc32.h include/config/ppc64.h \
		include/config/superh32.h include/config/superh64.h \
		include/config/x86_32.h include/config/x86_64.h)

# Workaround for make < 3.81, where .SECONDEXPANSION doesn't work.
# It'll end up depending on these targets, so make them a PHONY rule which
# depends on _all_ the directories in $(firmware-dirs), and it'll work out OK.
PHONY += $(objtree)/$$(%) $(objtree)/$(obj)/$$(%)
$(objtree)/$$(%) $(objtree)/$(obj)/$$(%): $(firmware-dirs)
	@true

# For the $$(dir %) trick, where we need % to be expanded first.
.SECONDEXPANSION:

$(patsubst %,$(obj)/%.gen.S, $(fw-shipped-y)): %: $(wordsize_deps) \
		| $(objtree)/$$(dir %)
	$(call cmd,fwbin,$(patsubst %.gen.S,%,$@))
$(patsubst %,$(obj)/%.gen.S, $(fw-external-y)): %: $(wordsize_deps) \
		include/config/builtin/firmware/dir.h | $(objtree)/$$(dir %)
	$(call cmd,fwbin,$(fwabs)/$(patsubst $(obj)/%.gen.S,%,$@))

# The .o files depend on the binaries directly; the .S files don't.
$(patsubst %,$(obj)/%.gen.o, $(fw-shipped-y)): %.gen.o: %
$(patsubst %,$(obj)/%.gen.o, $(fw-external-y)): $(obj)/%.gen.o: $(fwdir)/%

$(obj)/%: $(obj)/%.ihex | $(objtree)/$(obj)/$$(dir %)
	$(call cmd,ihex)

$(firmware-dirs):
	$(call cmd,mkdir)

obj-y := $(patsubst %,%.gen.o, $(firmware-y))

# Remove .S files and binaries created from ihex
# (during 'make clean' .config isn't included so they're all in $(fw-shipped-))
targets := $(fw-shipped-) $(patsubst $(obj)/%,%, \
				$(shell find $(obj) -name \*.gen.S 2>/dev/null))

# Without this, built-in.o won't be created when it's empty, and the
# final vmlinux link will fail.
obj-n := dummy