GNU ARM汇编--(十七)u-boot的makefile和mkconfig解读

1. stackusageifsupported
2. CFLAGS_STACK:=$(callcc-option,-fstack-usage)
3. CFLAGS+=$(CFLAGS_STACK)
5. #$(CPPFLAGS)sets-g,whichcausesgcctopassasuitable-g
6. #optiontotheassembler.
7. AFLAGS_DEBUG:=
9. #turnjbsrintojsrform68k
10. ifeq($(ARCH),m68k)
11. ifeq($(findstring3.4,$(shell$(CC)--version)),3.4)
12. AFLAGS_DEBUG:=-Wa,-gstabs,-S
13. endif
14. endif
16. AFLAGS:=$(AFLAGS_DEBUG)-D__ASSEMBLY__$(CPPFLAGS)
18. LDFLAGS+=$(PLATFORM_LDFLAGS)
19. LDFLAGS_FINAL+=-Bstatic
21. LDFLAGS_u-boot+=-T$(obj)u-boot.lds$(LDFLAGS_FINAL)
22. ifneq($(CONFIG_SYS_TEXT_BASE),)
23. LDFLAGS_u-boot+=-Ttext$(CONFIG_SYS_TEXT_BASE)
24. endif
26. LDFLAGS_u-boot-spl+=-T$(obj)u-boot-spl.lds$(LDFLAGS_FINAL)
27. ifneq($(CONFIG_SPL_TEXT_BASE),)
28. LDFLAGS_u-boot-spl+=-Ttext$(CONFIG_SPL_TEXT_BASE)
29. endif
31. #LocationofausableBFDlibrary,wherewedefine"usable"as
32. #"builtfor${HOST},supports${TARGET}".Sensiblevaluesare
33. #-Whencross-compiling:therootofthecross-environment
34. #-Linux/ppc(native):/usr
35. #-NetBSD/ppc(native):youlose...(mustextractthesefromthe
36. #binutilsbuilddirectory,plusthenativeandU-Bootinclude
37. #filesdontlikeeachother)
38. #
39. #Sofar,thisisusedonlybytools/gdb/Makefile.
41. ifeq($(HOSTOS),darwin)
42. BFD_ROOT_DIR=/usr/local/tools
43. else
44. ifeq($(HOSTARCH),$(ARCH))
45. #native
46. BFD_ROOT_DIR=/usr
47. else
48. #BFD_ROOT_DIR=/LinuxPPC/CDK#Linux/i386
49. #BFD_ROOT_DIR=/usr/pkg/cross#NetBSD/i386
50. BFD_ROOT_DIR=/opt/powerpc
51. endif
52. endif
54. #########################################################################
56. exportHOSTCCHOSTCFLAGSHOSTLDFLAGSPEDCFLAGSHOSTSTRIPCROSS_COMPILE
57. ASLDCCCPPARNMSTRIPOBJCOPYOBJDUMPMAKE
58. exportCONFIG_SYS_TEXT_BASEPLATFORM_CPPFLAGSPLATFORM_RELFLAGSCPPFLAGSCFLAGSAFLAGS
60. #########################################################################
62. #Allowboardstousecustomoptimizeflagsonaperdir/filebasis
63. BCURDIR=$(subst$(SRCTREE)/,,$(CURDIR:$(obj)%=%))
64. ALL_AFLAGS=$(AFLAGS)$(AFLAGS_$(BCURDIR)/$(@F))$(AFLAGS_$(BCURDIR))
65. ALL_CFLAGS=$(CFLAGS)$(CFLAGS_$(BCURDIR)/$(@F))$(CFLAGS_$(BCURDIR))
66. EXTRA_CPPFLAGS=$(CPPFLAGS_$(BCURDIR)/$(@F))$(CPPFLAGS_$(BCURDIR))
67. ALL_CFLAGS+=$(EXTRA_CPPFLAGS)
69. #The_DEPversionusesthe$
70. #Seerules.mk
71. EXTRA_CPPFLAGS_DEP=$(CPPFLAGS_$(BCURDIR)/$(addsuffix.o,$(basename$<)))
72. $(CPPFLAGS_$(BCURDIR))
73. $(obj)%.s:%.S
74. $(CPP)$(ALL_AFLAGS)-o$@$
75. $(obj)%.o:%.S
76. $(CC)$(ALL_AFLAGS)-o$@$<-c
77. $(obj)%.o:%.c
78. $(CC)$(ALL_CFLAGS)-o$@$<-c
79. $(obj)%.i:%.c
80. $(CPP)$(ALL_CFLAGS)-o$@$<-c
81. $(obj)%.s:%.c
82. $(CC)$(ALL_CFLAGS)-o$@$<-c-S
84. #########################################################################
86. #Ifthelistofobjectstolinkisempty,justcreateanemptybuilt-in.o
87. cmd_link_o_target=$(if$(strip$1),
88. $(LD)$(LDFLAGS)-r-o$@$1,
89. rm-f$@;$(AR)rcs$@)
91. #########################################################################

最后分析下make:

[cpp]view plaincopy

1. $(obj)include/autoconf.mk.dep:$(obj)include/config.hinclude/common.h
2. @$(XECHO)Generating$@;
3. set-e;
4. :Generatethedependancies;
5. $(CC)-xc-DDO_DEPS_ONLY-M$(CFLAGS)$(CPPFLAGS)
6. -MQ$(obj)include/autoconf.mkinclude/common.h>$@
8. $(obj)include/autoconf.mk:$(obj)include/config.h
9. @$(XECHO)Generating$@;
10. set-e;
11. :Extracttheconfigmacros;
12. $(CPP)$(CFLAGS)-DDO_DEPS_ONLY-dMinclude/common.h|
13. sed-n-ftools/scripts/define2mk.sed>$@.tmp&&
14. mv$@.tmp$@

第二个是根据include/config.h的文件内容,利用tools/scripts/define2mk.sed脚本将所有的CONFIG提取到autoconf.mk文件中

终极目标是:ALL-y += $(obj)u-boot.srec $(obj)u-boot.bin $(obj)System.map

u-boot.srec也是根据u-boot用objcopy工具搞出来的,不知的什么作用

u-boot.bin也是根据u-boot用objcopy工具搞出来的,最终烧写的二进制bin档

System.map是符号列表

[cpp]view plaincopy

1. $(obj)u-boot.bin:$(obj)u-boot
2. $(OBJCOPY)${OBJCFLAGS}-Obinary$<$@
3. $(BOARD_SIZE_CHECK)
4. ###################################################################################
5. #要得到最后的