MIPS: Add uImage build target

Add a uImage build target for MIPS, which builds uImage.gz (a U-Boot
image of vmlinux.bin.gz), and then symlinks it to uImage. This allows
for the use of other compression algorithms in future, and is how a few
other architectures do it.

It's enabled conditionally on load-y >= 0xffffffff80000000 which
hopefully allows 64bit kernels to also work as long as the load and
entry address can be represented by the 32bit addresses in the U-Boot
image format.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5795/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/mips/boot/Makefile b/arch/mips/boot/Makefile
index 851261e9fdc0..1466c0026093 100644
--- a/arch/mips/boot/Makefile
+++ b/arch/mips/boot/Makefile
@@ -40,3 +40,18 @@ quiet_cmd_srec = OBJCOPY $@
       cmd_srec = $(OBJCOPY) -S -O srec $(strip-flags) $(VMLINUX) $@
 $(obj)/vmlinux.srec: $(VMLINUX) FORCE
         $(call if_changed,srec)
+
+UIMAGE_LOADADDR  = $(VMLINUX_LOAD_ADDRESS)
+UIMAGE_ENTRYADDR = $(VMLINUX_ENTRY_ADDRESS)
+
+$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE
+        $(call if_changed,gzip)
+
+targets += uImage.gz
+$(obj)/uImage.gz: $(obj)/vmlinux.bin.gz FORCE
+        $(call if_changed,uimage,gzip)
+
+targets += uImage
+$(obj)/uImage: $(obj)/uImage.gz FORCE
+        @ln -sf $(notdir $<) $@
+        @echo '  Image $@ is ready'