uImage: 使用gzip compressed方式生成uImage

UBOOT解压缩内核比内核自解压要快1.6s，可以提高启动速度。
不压缩是最快的，lzo稍慢，以后有机会可以迁移到lzo压缩方式。

diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
index 4a590f4113e2af044ea1764aeb0681ad7f50a74c..d4ed498aefceda884c39665e4561a0621626e328 100644 (file)
--- a/arch/arm/boot/Makefile
+++ b/arch/arm/boot/Makefile
@@ -61,7 +61,7 @@ endif
 
 quiet_cmd_uimage = UIMAGE  $@
       cmd_uimage = $(CONFIG_SHELL) $(MKIMAGE) -A arm -O linux -T kernel \
-                  -C none -a $(LOADADDR) -e $(STARTADDR) \
+                  -C gzip -a $(LOADADDR) -e $(STARTADDR) \
                   -n 'Linux-$(KERNELRELEASE)' -d $< $@
 
 ifeq ($(CONFIG_ZBOOT_ROM),y)
@@ -77,9 +77,13 @@ else
 $(obj)/uImage: STARTADDR=$(LOADADDR)
 endif
 
-$(obj)/uImage: $(obj)/zImage FORCE
+$(obj)/Image.gz: $(obj)/Image FORCE
+       $(call if_changed,gzip)
+       @echo '  Image:  $@ is ready'
+
+$(obj)/uImage: $(obj)/Image.gz FORCE
        $(call if_changed,uimage)
-       @echo '  Image $@ is ready'
+       @echo '  Image:  $@ is ready'
 
 $(obj)/bootp/bootp: $(obj)/zImage initrd FORCE
        $(Q)$(MAKE) $(build)=$(obj)/bootp $@