Makefile: Add target for building bootable SPL image for SoCFPGA

Add build target for generating boot partition images recognised by
the SoCFPGA BootROM. The SoCFPGA BootROM expects four copies of the
u-boot-spl-dtb.sfp at the beginning of boot partition. Those are
u-boot-spl-dtb.bin augmented by a header with which the BootROM can
work. The u-boot-dtb.img uImage is appended to this to produce a
full boot partition image, the u-boot-with-spl-dtb.sfp . This is
the name of the final target.
Signed-off-by: NMarek Vasut <marex@denx.de>

Makefile

@@ -1020,6 +1020,15 @@ u-boot-nand.gph: u-boot.bin FORCE
 	$(call if_changed,mkimage)
 	@dd if=/dev/zero bs=8 count=1 2>/dev/null >> $@
 
+ifneq ($(CONFIG_ARCH_SOCFPGA),)
+quiet_cmd_socboot = SOCBOOT $@
+cmd_socboot = cat	spl/u-boot-spl-dtb.sfp spl/u-boot-spl-dtb.sfp	\
+			spl/u-boot-spl-dtb.sfp spl/u-boot-spl-dtb.sfp	\
+			u-boot-dtb.img > $@ || rm -f $@
+u-boot-with-spl-dtb.sfp: spl/u-boot-spl-dtb.sfp u-boot-dtb.img FORCE
+	$(call if_changed,socboot)
+endif
+
 # x86 uses a large ROM. We fill it with 0xff, put the 16-bit stuff (including
 # reset vector) at the top, Intel ME descriptor at the bottom, and U-Boot in
 # the middle.
@@ -1298,6 +1307,9 @@ spl/u-boot-spl: tools prepare $(if $(CONFIG_OF_SEPARATE),dts/dt.dtb)
 spl/sunxi-spl.bin: spl/u-boot-spl
 	@:
 
+spl/u-boot-spl-dtb.sfp: spl/u-boot-spl
+	@:
+
 tpl/u-boot-tpl.bin: tools prepare
 	$(Q)$(MAKE) obj=tpl -f $(srctree)/scripts/Makefile.spl all
 

scripts/Makefile.spl

@@ -163,6 +163,10 @@ ifdef CONFIG_SAMSUNG
 ALL-y	+= $(obj)/$(BOARD)-spl.bin
 endif
 
+ifdef CONFIG_ARCH_SOCFPGA
+ALL-y	+= $(obj)/$(SPL_BIN)-dtb.sfp
+endif
+
 ifdef CONFIG_SUNXI
 ALL-y	+= $(obj)/sunxi-spl.bin
 endif
@@ -231,6 +235,12 @@ ifneq ($(CONFIG_SPL_TEXT_BASE),)
 LDFLAGS_$(SPL_BIN) += -Ttext $(CONFIG_SPL_TEXT_BASE)
 endif
 
+ifdef CONFIG_ARCH_SOCFPGA
+MKIMAGEFLAGS_$(SPL_BIN)-dtb.sfp = -T socfpgaimage
+$(obj)/$(SPL_BIN)-dtb.sfp: $(obj)/$(SPL_BIN)-dtb.bin FORCE
+	$(call if_changed,mkimage)
+endif
+
 ifdef CONFIG_SUNXI
 quiet_cmd_mksunxiboot = MKSUNXI $@
 cmd_mksunxiboot = $(objtree)/tools/mksunxiboot $< $@