uboot understanding

make---》Define the system structure---》Define the host operating system type---》Define the shell that executes the shell script---》

make XXX_config ---》Execute the mkconfig of the top-level directory (a script)

The mkconfig script does three things: 1. Create a soft link 2. Create include/configs.mk 3. Create include/config.h

1. The soft link connects a:arm common header file b:header file for specific cpu c:special files for cpu (structure, assembly function...)

2. The include/config.mk file contains: ARCH CPU BOARD VENDOR SOC etc.

3.include/config.h contains some common header files: config_cmd_defaults.h config_defaults.h configs/XXX.h asm/config.h

make all--->sinclude $(obj)inluce/autoconf.mk (include file in include config.h)--->sinclude $(obj)include/autoconf.mk.dep (include macro definition in include config.h|commod.h)--->include include/config.mk (the one generated above)--->include top-level config.mk (does 3 things) 1. Specify the assembly tool 2. Specify the assembly rules 3. Include the required config.mk

3. What is included: For example: arm/config.mk smdk64XX/config.mk arm1176/config.mk $(board)/config.mk (it sets the text address)

u-boot: depend $(SUBDIRS) $(objs) $(libs) ....$u-boot.lds

The depend rule is to go into each required directory and run make_depend

The _depend target is in the top-level rules.mk, which will generate the target dependency files required in the current directory.

ARCH CPU BOARD VENDOR SOC

$(MKCONFIG) in mini6410 mini6410 arm s3c64xx mini6410 samsung s3c6410 Nand ram256

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