Chinaunix首页 | 论坛 | 博客

武溪嵌人zhangdanf.blog.chinaunix.net

首页　| 　博文目录　| 　关于我

武溪嵌人

  • 博客访问： 138443
  • 博文数量： 33
  • 博客积分： 15
  • 博客等级： 民兵
  • 技术积分： 42
  • 用 户 组： 普通用户
  • 注册时间： 2012-09-22 10:23
个人简介

嵌入式带动整个社会！

文章分类

全部博文（33）

文章存档

2015年（4）

2014年（15）

2013年（8）

2012年（6）

我的朋友
最近访客
推荐博文
相关博文
** am335x中uboot的编译流程

分类： 嵌入式

2014-03-25 22:08:02

原文地址：** am335x中uboot的编译流程 作者：andyhzw

PC操作系统：ubuntu11.10

开发板：am335x_evm

uboot ：u-boot-2011.09-psp04.06.00.07


生成所需文件：MLO(SPL),uboot.img，命令如下：

#make O=am335x am335x_evm


注意：默认uboot的根目录为 ./ 


makefile的执行流程如下：

1，生成板子依赖文件：


1,首先根据命令判断是否需要生成目录来保存将要生成的所需的各个文件： 


#########################################################################
#@设定编译输出目录@:
#	函数$( origin, variable) 输出的结果是一个字符串，输出结果由变量variable定义的方式决定，
#	若variable在命令行中定义过，则origin函数返回值为"command line"。
#	假若在命令行中执行了“export BUILD_DIR=/tmp/build”的命令，则“$(origin O)”值为“command line”，
#	而BUILD_DIR被设置为“/tmp/build”。
#
#	假若在命令行中执行了“make O=am335x am335x_evm”的命令，则“$(origin O)”值为“command line”，
#	而BUILD_DIR被设置为“am335x”。	
#########################################################################
ifdef O
ifeq ("$(origin O)", "command line")
BUILD_DIR := $(O)
endif
endif

#判断 BUILD_DIR 变量是否为空，当前 BUILD_DIR 为 am335x，条件为真，则 saved-output 为 am335x
ifneq ($(BUILD_DIR),)
saved-output := $(BUILD_DIR)

#若${BUILD_DIR}表示的目录没有定义，则创建该目录。
# Attempt to create a output directory.
$(shell [ -d ${BUILD_DIR} ] || mkdir -p ${BUILD_DIR})

#若$(BUILD_DIR)为创建失败或不存在，则将其赋值为当前目录路径（源代码目录）。
#并检查$(BUILD_DIR)目录是否存在。
#Pwd命令用以获取当前路径
# Verify if it was successful.
BUILD_DIR := $(shell cd $(BUILD_DIR) && /bin/pwd)
$(if $(BUILD_DIR),,$(error output directory "$(saved-output)" does not exist))
endif # ifneq ($(BUILD_DIR),)


此时会在uboot根目录下生成一个 am335x的目录：./am335x/


2，生成板子依赖文件：
 


$(obj).boards.depend:	boards.cfg
	awk '(NF && $$1 !~ /^#/) { print $$1 ": " $$1 "_config; $$(MAKE)" }' $< > $@
读取uboot根目录下的 boards.cfg 文件生成 .boards.depend 隐藏文件，该文件位于 obj 目录下。



2，执行根目录下的mkconfig文件： 


%_config::	unconfig
	@$(MKCONFIG) -A $(@:_config=)

   即：         mkconfig -A am335x_evm


其功能实现如下：


设为 ： ./ （即当前目录，即uboot根目录）
1，创建include目录：./am335x/include/
        创建 asm目录：./am335x/include/asm/
            创建符号链接 asm/arch，即 ./am335x/include/asm/arch 指向 ./arch/arm/include/asm/arch-ti81xx/ 目录
            创建符号链接 asm/proc，即 ./am335x/include/asm/proc 指向 ./arch/arm/include/asm/proc-armv/ 目录.

2，创建include2目录：./am335x/include2/
        创建符号链接asm，即 ./am335x/include2/asm 指向 ./arch/arm/include/asm    

    ./am335x/
        |------include/
        |         |------asm/
        |         |       |------arch      
        |         |       |------proc
        |         |------config.mk
        |         |------config.h
        |------include2/
                  |------asm


3，执行make：

            运行 config.mk 文件。


以下是uboot根目录下的makefile，mkconfig文件的详解：

makefile 详解： 


#
# (C) Copyright 2000-2011
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundatio; either version 2 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#

VERSION = 2011
PATCHLEVEL = 09
SUBLEVEL =
EXTRAVERSION =
ifneq "$(SUBLEVEL)" ""
U_BOOT_VERSION = $(VERSION).$(PATCHLEVEL).$(SUBLEVEL)$(EXTRAVERSION)
else
U_BOOT_VERSION = $(VERSION).$(PATCHLEVEL)$(EXTRAVERSION)
endif
TIMESTAMP_FILE = $(obj)include/timestamp_autogenerated.h
VERSION_FILE = $(obj)include/version_autogenerated.h

#########################################################################
#@定义主机系统架构@:
#	“sed –e”表示后面跟的是一串命令脚本，而表达式“s/abc/def/”表示要从标准输入中，
#	查找到内容为“abc”的，然后替换成“def”。其中“abc”表达式用可以使用“.”作为通配符。
#	命令“uname –m”将输出主机CPU的体系架构类型。作者的电脑使用Intel Core2系列的CPU，
#	因此“uname –m”输出“i686”。 “i686”可以匹配命令“sed -e s/i.86/i386/”中的“i.86”，
#	因此在作者的机器上执行Makefile，HOSTARCH 将被设置成“i386” 。
#########################################################################
HOSTARCH := $(shell uname -m | \
	sed -e s/i.86/x86/ \
	    -e s/sun4u/sparc64/ \
	    -e s/arm.*/arm/ \
	    -e s/sa110/arm/ \
	    -e s/ppc64/powerpc/ \
	    -e s/ppc/powerpc/ \
	    -e s/macppc/powerpc/\
	    -e s/sh.*/sh/)

#########################################################################
#@定义主机操作系统类型@:
#	“uname –s”输出主机内核名字，作者使用Linux发行版Ubuntu11.10，因此“uname –s”结果是“Linux”。
#	“tr '[:upper:]' '[:lower:]'”作用是将标准输入中的所有大写字母转换为响应的小写字母。
#	因此执行结果是将HOSTOS 设置为“linux”。
#########################################################################
HOSTOS := $(shell uname -s | tr '[:upper:]' '[:lower:]' | \
	    sed -e 's/\(cygwin\).*/cygwin/')

#########################################################################
#@定义执行shell脚本的shell@:
#	"$$BASH"的作用实质上是生成了字符串“$BASH”（前一个$号的作用是指明第二个$是普通的字符）。
#	若执行当前Makefile的shell中定义了“$BASH”环境变量，且文件“$BASH”是可执行文件，
#	则SHELL的值为“$BASH”。否则，若“/bin/bash”是可执行文件，则SHELL值为“/bin/bash”。
#	若以上两条都不成立，则将“sh”赋值给SHELL变量。
#	由于作者的机器安装了bash shell，SHELL 被设置为 /bin/bash。
#########################################################################
# Set shell to bash if possible, otherwise fall back to sh
SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
	else if [ -x /bin/bash ]; then echo /bin/bash; \
	else echo sh; fi; fi)

#导出变量HOSTARCH HOSTOS SHELL，使别的文件可以使用这些变量
export	HOSTARCH HOSTOS SHELL

# Deal with colliding definitions from tcsh etc.
VENDOR=

#因为MAKEFLAGS变量的字符串为空，找不到s字符串，所以ifeq条件为真，则XECHO = echo 
# Allow for silent builds
ifeq (,$(findstring s,$(MAKEFLAGS)))
XECHO = echo
else
XECHO = :
endif

#########################################################################
#
# U-boot build supports producing a object files to the separate external
# directory. Two use cases are supported:
#
# 1) Add O= to the make command line
# 'make O=/tmp/build all'
#
# 2) Set environement variable BUILD_DIR to point to the desired location
# 'export BUILD_DIR=/tmp/build'
# 'make'
#
# The second approach can also be used with a MAKEALL script
# 'export BUILD_DIR=/tmp/build'
# './MAKEALL'
#
# Command line 'O=' setting overrides BUILD_DIR environent variable.
#
# When none of the above methods is used the local build is performed and
# the object files are placed in the source directory.
#

#########################################################################
#@设定编译输出目录@:
#	函数$( origin, variable) 输出的结果是一个字符串，输出结果由变量variable定义的方式决定，
#	若variable在命令行中定义过，则origin函数返回值为"command line"。
#	假若在命令行中执行了“export BUILD_DIR=/tmp/build”的命令，则“$(origin O)”值为“command line”，
#	而BUILD_DIR被设置为“/tmp/build”。
#
#	假若在命令行中执行了“make O=am335x am335x_evm”的命令，则“$(origin O)”值为“command line”，
#	而BUILD_DIR被设置为“am335x”。	
#########################################################################
ifdef O
ifeq ("$(origin O)", "command line")
BUILD_DIR := $(O)
endif
endif

#判断 BUILD_DIR 变量是否为空，当前 BUILD_DIR 为 am335x，条件为真，则 saved-output 为 am335x
ifneq ($(BUILD_DIR),)
saved-output := $(BUILD_DIR)

#若${BUILD_DIR}表示的目录没有定义，则创建该目录。
# Attempt to create a output directory.
$(shell [ -d ${BUILD_DIR} ] || mkdir -p ${BUILD_DIR})

#若$(BUILD_DIR)为创建失败或不存在，则将其赋值为当前目录路径（源代码目录）。
#并检查$(BUILD_DIR)目录是否存在。
#Pwd命令用以获取当前路径
# Verify if it was successful.
BUILD_DIR := $(shell cd $(BUILD_DIR) && /bin/pwd)
$(if $(BUILD_DIR),,$(error output directory "$(saved-output)" does not exist))
endif # ifneq ($(BUILD_DIR),)

#########################################################################
#CURDIR变量指示Make当前的工作目录，由于当前Make在U-Boot顶层目录执行Makefile，
#因此CURDIR此时就是U-Boot顶层目录。
#执行完上面的代码后， SRCTREE，src变量就是U-Boot代码顶层目录，而OBJTREE，obj变量就是输出目录，
#若没有定义BUILD_DIR环境变量，则SRCTREE，src变量与OBJTREE，obj变量都是U-Boot源代码目录。
#而MKCONFIG则表示U-Boot根目录下的mkconfig脚本。
#if函数计算OBJTREE的值，如果BUILD_DIR不为空，if函数的值就是BUILD_DIR，否则是CURDIR.
#CURDIR是个环境变量。代表当前文件的目录,即uboot根目录，设为 : ./。
#	CURDIR		= ./
#	OBJTREE		= ./am335x
#	SPLTREE		= ./am335x/spl
#	SRCTREE		= ./
#	TOPDIR		= ./
#	LNDIR		= ./am335x
#导出变量TOPDIR SRCTREE OBJTREE SPLTREE，使别的文件可以使用这些变量
#########################################################################
OBJTREE		:= $(if $(BUILD_DIR),$(BUILD_DIR),$(CURDIR))
SPLTREE		:= $(OBJTREE)/spl
SRCTREE		:= $(CURDIR)
TOPDIR		:= $(SRCTREE)
LNDIR		:= $(OBJTREE)
export	TOPDIR SRCTREE OBJTREE SPLTREE

#	MKCONFIG	= ./mkconfig
#导出变量MKCONFIG
MKCONFIG	:= $(SRCTREE)/mkconfig
export MKCONFIG

#########################################################################
#判断变量OBJTREE 与 SRCTREE 是否相等，OBJTREE为./am335x，SRCTREE为./变量，条件为真。
#则变量 REMOTE_BUILD 为 1，
#导出变量 REMOTE_BUILD
######################################################################### 
ifneq ($(OBJTREE),$(SRCTREE))
REMOTE_BUILD	:= 1
export REMOTE_BUILD
endif

#########################################################################
#判断变量OBJTREE 与 SRCTREE 是否相等，OBJTREE为./am335x，SRCTREE为./变量，条件为真。
#则	obj 为 ./am335x/
#	src 为 ./
#导出变量 obj src
######################################################################### 
# $(obj) and (src) are defined in config.mk but here in main Makefile
# we also need them before config.mk is included which is the case for
# some targets like unconfig, clean, clobber, distclean, etc.
ifneq ($(OBJTREE),$(SRCTREE))
obj := $(OBJTREE)/
src := $(SRCTREE)/
else
obj :=
src :=
endif
export obj src

#失能导出变量 CDPATH的使用域，这样下文中如果定义了或使用了CDPATH变量，将不会收到导出变量CDPATH的影响。
# Make sure CDPATH settings don't interfere
unexport CDPATH

# The "tools" are needed early, so put this first
# Don't include stuff already done in $(LIBS)
SUBDIRS	= tools \
	  examples/standalone \
	  examples/api

#定义SUBDIRS VERSION_FILE伪目标
.PHONY : $(SUBDIRS) $(VERSION_FILE)

#########################################################################
#使用“$(wildcard *.c) ”来获取工作目录下的所有的.c 文件列表
#在当前例子中，则是为了找到 ./am335x/include/config.mk
#判断是否找到 ./am335x/include/config.mk
#########################################################################
ifeq ($(obj)include/config.mk,$(wildcard $(obj)include/config.mk))

#########################################################################
#使用“include FILENAMES... ”，make程序处理时，如果“FILENAMES ”列表
#	中的任何一个文件不能正常读取而且不存在一个创建此文件的规则时make 程序将会提示错误并退出。
# 
#使用“-include FILENAMES... ”的情况是，当所包含的文件不存在或者不存在一
#	个规则去创建它，make程序会继续执行，只有真正由于不能正确完成终极目标的重建
#	时（某些必需的目标无法在当前已读取的makefile 文件内容中找到正确的重建规则），
#	才会提示致命错误并退出。 
#
#为了和其它的make 程序进行兼容。也可以使用“sinclude ”来代替“-include ”（GNU所支持的方式）
#
# include/autoconf.mk(./am335x/include/autoconf.mk)文件中是与开发板相关的一些宏定义,
#	在Makefile执行过程中需要根据某些宏来确定执行哪些操作。
# include/autoconf.mk生成的规则为下文的：$(obj)include/autoconf.mk: $(obj)include/config.h
# include/autoconf.mk.dep 同理.
#########################################################################
# Include autoconf.mk before config.mk so that the config options are available
# to all top level build files.  We need the dummy all: target to prevent the
# dependency target in autoconf.mk.dep from being the default.
#执行make的时候默认就是执行make all
all:
sinclude $(obj)include/autoconf.mk.dep
sinclude $(obj)include/autoconf.mk

#包含./am335x/include/config.mk 文件,加载该文件中的ARCH CPU BOARD VENDOR SOC，并导出
# load ARCH, BOARD, and CPU configuration
include $(obj)include/config.mk
export	ARCH CPU BOARD VENDOR SOC

#########################################################################
#FOO ?= bar  
#	其含义是，如果 FOO 没有被定义过，那么变量 FOO 的值就是“bar”，如果 FOO 先前被定义
#	过，那么这条语将什么也不做，其等价于：  
  
#	ifeq ($(origin FOO), undefined)  
#	FOO = bar  
#	endif  

#若主机架构与开发板结构相同，就使用主机的编译器，而不是交叉编译器
#当前 HOSTARCH 为 i386
#当前 ARCH     为 arm
#条件为假，则 CROSS_COMPILE 为交叉编译器,即 CROSS_COMPILE = arm-arago-linux-gnueabi-
#########################################################################
# set default to nothing for native builds
ifeq ($(HOSTARCH),$(ARCH))
CROSS_COMPILE ?=
endif

#包含 ./config.mk 文件,其主要是一些变量和函数的定义,编译链接的参数设置以及依赖规则.
# load other configuration
include $(TOPDIR)/config.mk

#########################################################################
#判断是否定义了 LDSCRIPT 变量，当前并没有定义该变量，条件为真
#
#如果定义了CONFIG_SYS_LDSCRIPT，将CONFIG_SYS_LDSCRIPT代表的字符串去掉双引号后赋值给LDSCRIPT变量    
#这里我们并没有定义CONFIG_SYS_LDSCRIPT  
#########################################################################
# If board code explicitly specified LDSCRIPT or CONFIG_SYS_LDSCRIPT, use
# that (or fail if absent).  Otherwise, search for a linker script in a
# standard location.
ifndef LDSCRIPT
	#LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds.debug
	ifdef CONFIG_SYS_LDSCRIPT
		# need to strip off double quotes
		LDSCRIPT := $(subst ",,$(CONFIG_SYS_LDSCRIPT))
	endif
endif

#BOARDDIR 定义与 ./mkconfig中，在当前例子中 BOARDDIR = $(VENDOR)/$(BOARD) = ti/am335x

#########################################################################
#如果没有用CONFIG_SYS_LDSCRIPT指定LDSCRIPT，那么就在以下几个地方搜 
#判断是否定义了 LDSCRIPT 变量，当前并没有定义该变量，条件为真  
#########################################################################
ifndef LDSCRIPT
	#########################################################################
	#如果CONFIG_NAND_U_BOOT变量是否等于 y，当前没有定义CONFIG_NAND_U_BOOT变量，条件为假。
	#则不执行条件中的代码
	#########################################################################
	ifeq ($(CONFIG_NAND_U_BOOT),y)
		LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot-nand.lds
		ifeq ($(wildcard $(LDSCRIPT)),)
			LDSCRIPT := $(TOPDIR)/$(CPUDIR)/u-boot-nand.lds
		endif
	endif
	
	#########################################################################
	#判断变量 LDSCRIPT 是否为空，当前 LDSCRIPT 为空，条件为真，执行条件中的代码。
	# BOARDDIR 定义与 ./mkconfig中，在当前例子中 BOARDDIR = $(VENDOR)/$(BOARD) = ti/am335x
	# TOPDIR = ./
	# LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds -> LDSCRIPT = ./board/ti/am335x/u-boot.lds,
	# 查找 ./board/ti/am335x/ 目录下的 u-boot.lds 文件，没有找到对应的文件，所以  LDSCRIPT 为空。
	#########################################################################
	ifeq ($(wildcard $(LDSCRIPT)),)
		LDSCRIPT := $(TOPDIR)/board/$(BOARDDIR)/u-boot.lds
	endif
	
	#########################################################################
	#判断变量 LDSCRIPT 是否为空，当前 LDSCRIPT 为空，条件为真，执行条件中的代码。
	# 在顶层 config.mk 中 得 CPUDIR	= CPUDIR=arch/$(ARCH)/cpu/$(CPU) = arch/arm/cpu/armv7
	# TOPDIR = ./
	# LDSCRIPT := $(TOPDIR)/$(CPUDIR)/u-boot.lds -> LDSCRIPT = ./arch/arm/cpu/armv7/u-boot.lds,
	# 查找 ./arch/arm/cpu/armv7/ 目录下的 u-boot.lds 文件，找到了对应的 u-boot.lds 文件，
	# 因此，LDSCRIPT = ./arch/arm/cpu/armv7/u-boot.lds
	#########################################################################	
	ifeq ($(wildcard $(LDSCRIPT)),)
		LDSCRIPT := $(TOPDIR)/$(CPUDIR)/u-boot.lds
	endif
	
	#########################################################################
	#判断变量 LDSCRIPT 是否为空， 当前 LDSCRIPT = ./arch/arm/cpu/armv7/u-boot.lds，
	#条件为假，不执行条件中的代码
	#########################################################################	
	ifeq ($(wildcard $(LDSCRIPT)),)
$(error could not find linker script)
	endif
endif

#########################################################################
# U-Boot objects....order is important (i.e. start must be first)
# U-boot需要的目标文件，顺序很重要，start.o必须放第一位
# 在顶层 config.mk 中 得 CPUDIR	= CPUDIR=arch/$(ARCH)/cpu/$(CPU) = arch/arm/cpu/armv7
OBJS  = $(CPUDIR)/start.o

# 根据 ./am335x/include/config.mk 得 CPU    = armv7
# 在顶层 config.mk 中 得 CPUDIR	= CPUDIR=arch/$(ARCH)/cpu/$(CPU) = arch/arm/cpu/armv7
ifeq ($(CPU),x86)
OBJS += $(CPUDIR)/start16.o
OBJS += $(CPUDIR)/resetvec.o
endif
ifeq ($(CPU),ppc4xx)
OBJS += $(CPUDIR)/resetvec.o
endif
ifeq ($(CPU),mpc85xx)
OBJS += $(CPUDIR)/resetvec.o
endif

# obj = ./am335x
OBJS := $(addprefix $(obj),$(OBJS))

# 根据 ./am335x/include/config.mk 得 VENDOR = ti
LIBS  = lib/libgeneric.o
LIBS += lib/lzma/liblzma.o
LIBS += lib/lzo/liblzo.o
LIBS += lib/zlib/libz.o
LIBS += $(shell if [ -f board/$(VENDOR)/common/Makefile ]; then echo \
	"board/$(VENDOR)/common/lib$(VENDOR).o"; fi)
LIBS += $(CPUDIR)/lib$(CPU).o

#根据 ./am335x/include/config.mk 得 SOC    = ti81xx
ifdef SOC
LIBS += $(CPUDIR)/$(SOC)/lib$(SOC).o
endif
ifeq ($(CPU),ixp)
LIBS += arch/arm/cpu/ixp/npe/libnpe.o
endif

# 根据 ./am335x/include/config.mk 得 ARCH   = arm
LIBS += arch/$(ARCH)/lib/lib$(ARCH).o
LIBS += fs/cramfs/libcramfs.o fs/fat/libfat.o fs/fdos/libfdos.o fs/jffs2/libjffs2.o \
	fs/reiserfs/libreiserfs.o fs/ext2/libext2fs.o fs/yaffs2/libyaffs2.o \
	fs/ubifs/libubifs.o
LIBS += net/libnet.o
LIBS += disk/libdisk.o
LIBS += drivers/bios_emulator/libatibiosemu.o
LIBS += drivers/block/libblock.o
LIBS += drivers/dma/libdma.o
LIBS += drivers/fpga/libfpga.o
LIBS += drivers/gpio/libgpio.o
LIBS += drivers/hwmon/libhwmon.o
LIBS += drivers/i2c/libi2c.o
LIBS += drivers/input/libinput.o
LIBS += drivers/misc/libmisc.o
LIBS += drivers/mmc/libmmc.o
LIBS += drivers/mtd/libmtd.o
LIBS += drivers/mtd/nand/libnand.o
LIBS += drivers/mtd/onenand/libonenand.o
LIBS += drivers/mtd/ubi/libubi.o
LIBS += drivers/mtd/spi/libspi_flash.o
LIBS += drivers/net/libnet.o
LIBS += drivers/net/phy/libphy.o
LIBS += drivers/pci/libpci.o
LIBS += drivers/pcmcia/libpcmcia.o
LIBS += drivers/power/libpower.o
LIBS += drivers/spi/libspi.o
ifeq ($(CPU),mpc83xx)
LIBS += drivers/qe/libqe.o
LIBS += arch/powerpc/cpu/mpc8xxx/lib8xxx.o
endif
ifeq ($(CPU),mpc85xx)
LIBS += drivers/qe/libqe.o
LIBS += arch/powerpc/cpu/mpc8xxx/ddr/libddr.o
LIBS += arch/powerpc/cpu/mpc8xxx/lib8xxx.o
endif
ifeq ($(CPU),mpc86xx)
LIBS += arch/powerpc/cpu/mpc8xxx/ddr/libddr.o
LIBS += arch/powerpc/cpu/mpc8xxx/lib8xxx.o
endif
LIBS += drivers/rtc/librtc.o
LIBS += drivers/serial/libserial.o
LIBS += drivers/twserial/libtws.o
LIBS += drivers/usb/eth/libusb_eth.o
LIBS += drivers/usb/gadget/libusb_gadget.o
LIBS += drivers/usb/host/libusb_host.o
LIBS += drivers/usb/musb/libusb_musb.o
LIBS += drivers/usb/phy/libusb_phy.o
LIBS += drivers/video/libvideo.o
LIBS += drivers/watchdog/libwatchdog.o
LIBS += common/libcommon.o
LIBS += lib/libfdt/libfdt.o
LIBS += api/libapi.o
LIBS += post/libpost.o

#根据 ./am335x/include/config.mk 得 SOC    = ti81xx
ifeq ($(SOC),ti81xx)
LIBS += $(CPUDIR)/omap-common/libomap-common.o
endif
ifeq ($(SOC),omap3)
LIBS += $(CPUDIR)/omap-common/libomap-common.o
endif
ifeq ($(SOC),omap4)
LIBS += $(CPUDIR)/omap-common/libomap-common.o
endif

ifeq ($(SOC),s5pc1xx)
LIBS += $(CPUDIR)/s5p-common/libs5p-common.o
endif
ifeq ($(SOC),s5pc2xx)
LIBS += $(CPUDIR)/s5p-common/libs5p-common.o
endif

#########################################################################/*
#	8.3.6 $(addprefix PREFIX,NAMES…) 
#	函数名称：加前缀函数—addprefix。 
#
#	函数功能：为“NAMES…”中的每一个文件名添加前缀“PREFIX”。参数“ NAMES…”
#	是空格分割的文件名序列，将“SUFFIX”添加到此序列的每一个文件名之前。
# 
#	返回值：以单空格分割的添加了前缀“PREFIX”的文件名序列。 
#
#函数说明： 
#示例： 
#$(addprefix src/,foo bar) 
#返回值为“src/foo src/bar”。
#
#
# obj = ./am335x 
#########################################################################*/
LIBS := $(addprefix $(obj),$(sort $(LIBS)))
#定义LIBS TIMESTAMP_FILE伪目标
#TIMESTAMP_FILE = $(obj)include/timestamp_autogenerated.h -> ./am335x/include/timestamp_autogenerated.h
.PHONY : $(LIBS) $(TIMESTAMP_FILE)

# BOARDDIR 定义与 ./mkconfig中，在当前例子中 BOARDDIR = $(VENDOR)/$(BOARD) = ti/am335x
#根据 ./am335x/include/config.mk 得 BOARD  = am335x
LIBBOARD = board/$(BOARDDIR)/lib$(BOARD).o
LIBBOARD := $(addprefix $(obj),$(LIBBOARD))

# 没有定义 USE_PRIVATE_LIBGCC
# Add GCC lib
ifdef USE_PRIVATE_LIBGCC
ifeq ("$(USE_PRIVATE_LIBGCC)", "yes")
PLATFORM_LIBGCC = $(OBJTREE)/arch/$(ARCH)/lib/libgcc.o
else
PLATFORM_LIBGCC = -L $(USE_PRIVATE_LIBGCC) -lgcc
endif
else
# 在顶层 config.mk(./config.mk) 中 得CC,CFLAGS:
#CC = $(CROSS_COMPILE)gcc 
#CROSS_COMPILE = arm-arago-linux-gnueabi-
#CC = arm-arago-linux-gnueabi-gcc
PLATFORM_LIBGCC = -L $(shell dirname `$(CC) $(CFLAGS) -print-libgcc-file-name`) -lgcc
endif
PLATFORM_LIBS += $(PLATFORM_LIBGCC)
#导出变量 PLATFORM_LIBS
export PLATFORM_LIBS

# Special flags for CPP when processing the linker script.
# Pass the version down so we can handle backwards compatibility
# on the fly.
LDPPFLAGS += \
	-include $(TOPDIR)/include/u-boot/u-boot.lds.h \
	$(shell $(LD) --version | \
	  sed -ne 's/GNU ld version \([0-9][0-9]*\)\.\([0-9][0-9]*\).*/-DLD_MAJOR=\1 -DLD_MINOR=\2/p')

__OBJS := $(subst $(obj),,$(OBJS))
__LIBS := $(subst $(obj),,$(LIBS)) $(subst $(obj),,$(LIBBOARD))

#########################################################################
#########################################################################
#没有定义变量 CONFIG_BOARD_SIZE_LIMIT，因此 BOARD_SIZE_CHECK 为空
ifneq ($(CONFIG_BOARD_SIZE_LIMIT),)
BOARD_SIZE_CHECK = \
	@actual=`wc -c $@ | awk '{print $$1}'`; \
	limit=$(CONFIG_BOARD_SIZE_LIMIT); \
	if test $$actual -gt $$limit; then \
		echo "$@ exceeds file size limit:"; \
		echo "  limit:  $$limit bytes"; \
		echo "  actual: $$actual bytes"; \
		echo "  excess: $$((actual - limit)) bytes"; \
		exit 1; \
	fi
else
BOARD_SIZE_CHECK =
endif

#最终生成的各种镜像文件，及其生成方法
# Always append ALL so that arch config.mk's can add custom ones
ALL-y += $(obj)u-boot.srec $(obj)u-boot.bin $(obj)System.map

ALL-$(CONFIG_NAND_U_BOOT) += $(obj)u-boot-nand.bin
ALL-$(CONFIG_ONENAND_U_BOOT) += $(obj)u-boot-onenand.bin
ONENAND_BIN ?= $(obj)onenand_ipl/onenand-ipl-2k.bin
ALL-$(CONFIG_MMC_U_BOOT) += $(obj)mmc_spl/u-boot-mmc-spl.bin
ALL-$(CONFIG_SPL) += $(obj)spl/u-boot-spl.bin

all:		$(ALL-y)

# 在uboot顶层 config.mk 中 得 OBJCOPY = $(CROSS_COMPILE)objcopy -> arm-arago-linux-gnueabi-objcopy,
# 生成  .hex 格式的文件
$(obj)u-boot.hex:	$(obj)u-boot
		$(OBJCOPY) ${OBJCFLAGS} -O ihex $< $@
		
# 在uboot顶层 config.mk 中 得 OBJCOPY = $(CROSS_COMPILE)objcopy -> arm-arago-linux-gnueabi-objcopy,
# 生成某个格式的文件
$(obj)u-boot.srec:	$(obj)u-boot
		$(OBJCOPY) -O srec $< $@
		
# BOARD_SIZE_CHECK 为空
# 生成 .bin 文件
$(obj)u-boot.bin:	$(obj)u-boot
		$(OBJCOPY) ${OBJCFLAGS} -O binary $< $@
		$(BOARD_SIZE_CHECK)

$(obj)u-boot.ldr:	$(obj)u-boot
		$(CREATE_LDR_ENV)
		$(LDR) -T $(CONFIG_BFIN_CPU) -c $@ $< $(LDR_FLAGS)
		$(BOARD_SIZE_CHECK)

$(obj)u-boot.ldr.hex:	$(obj)u-boot.ldr
		$(OBJCOPY) ${OBJCFLAGS} -O ihex $< $@ -I binary

$(obj)u-boot.ldr.srec:	$(obj)u-boot.ldr
		$(OBJCOPY) ${OBJCFLAGS} -O srec $< $@ -I binary

# 在uboot顶层 config.mk 中 得 CONFIG_SYS_TEXT_BASE=0x80800000
$(obj)u-boot.img:	$(obj)u-boot.bin
		$(obj)tools/mkimage -A $(ARCH) -T firmware -C none \
		-O u-boot -a $(CONFIG_SYS_TEXT_BASE) -e 0 \
		-n $(shell sed -n -e 's/.*U_BOOT_VERSION//p' $(VERSION_FILE) | \
			sed -e 's/"[	 ]*$$/ for $(BOARD) board"/') \
		-d $< $@

$(obj)u-boot.imx:       $(obj)u-boot.bin
		$(obj)tools/mkimage -n  $(CONFIG_IMX_CONFIG) -T imximage \
		-e $(CONFIG_SYS_TEXT_BASE) -d $< $@

$(obj)u-boot.kwb:       $(obj)u-boot.bin
		$(obj)tools/mkimage -n $(CONFIG_SYS_KWD_CONFIG) -T kwbimage \
		-a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_TEXT_BASE) -d $< $@

$(obj)u-boot.sha1:	$(obj)u-boot.bin
		$(obj)tools/ubsha1 $(obj)u-boot.bin

$(obj)u-boot.dis:	$(obj)u-boot
		$(OBJDUMP) -d $< > $@

$(obj)u-boot.ubl:       $(obj)u-boot-nand.bin
		$(obj)tools/mkimage -n $(UBL_CONFIG) -T ublimage \
		-e $(CONFIG_SYS_TEXT_BASE) -d $< $@

GEN_UBOOT = \
		UNDEF_SYM=`$(OBJDUMP) -x $(LIBBOARD) $(LIBS) | \
		sed  -n -e 's/.*\($(SYM_PREFIX)__u_boot_cmd_.*\)/-u\1/p'|sort|uniq`;\
		cd $(LNDIR) && $(LD) $(LDFLAGS) $(LDFLAGS_$(@F)) $$UNDEF_SYM $(__OBJS) \
			--start-group $(__LIBS) --end-group $(PLATFORM_LIBS) \
			-Map u-boot.map -o u-boot
			
#########################################################################/*
#u-boot ELF文件镜像的生成是最关键的.
#u-boot 依赖depend $(SUBDIR_TOOLS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT) $(obj)u-boot.lds.
#然后用$(GEN_UBOOT)生成最后的u-boot,GEN_UBOOT就是用 ld 链接的过程
#########################################################################*/
$(obj)u-boot:	depend \
		$(SUBDIRS) $(OBJS) $(LIBBOARD) $(LIBS) $(LDSCRIPT) $(obj)u-boot.lds
		$(GEN_UBOOT)
		
#没有定义 CONFIG_KALLSYMS
ifeq ($(CONFIG_KALLSYMS),y)
		smap=`$(call SYSTEM_MAP,u-boot) | \
			awk '$$2 ~ /[tTwW]/ {printf $$1 $$3 "\\\\000"}'` ; \
		$(CC) $(CFLAGS) -DSYSTEM_MAP="\"$${smap}\"" \
			-c common/system_map.c -o $(obj)common/system_map.o
		$(GEN_UBOOT) $(obj)common/system_map.o
endif

# 在顶层 config.mk 中 得 CPUDIR	= CPUDIR=arch/$(ARCH)/cpu/$(CPU) = arch/arm/cpu/armv7
#依赖目标$(OBJS)，执行arch/arm/cpu/armv7 目录下的 makefile， 生成 ./am335x/arch/arm/cpu/armv7/start.o
#REMOTE_BUILD := 1
#看下$(if $(REMOTE_BUILD),$@,$(notdir $@))
#因为$(REMOTE_BUILD)为1,所以返回的是 $@ 的值,即 OBJS;
$(OBJS):	depend
		$(MAKE) -C $(CPUDIR) $(if $(REMOTE_BUILD),$@,$(notdir $@))

#依赖目标$(LIBS)，进入到LIBS包含的很多目录，执行make,生成很多.a文件
$(LIBS):	depend $(SUBDIRS)
		$(MAKE) -C $(dir $(subst $(obj),,$@))

# BOARDDIR 定义与 ./mkconfig中，在当前例子中 	BOARDDIR = $(VENDOR)/$(BOARD) = ti/am335x
# 根据 ./am335x/include/config.mk 得			BOARD  = am335x
#	LIBBOARD = board/$(BOARDDIR)/lib$(BOARD).o
#	LIBBOARD := $(addprefix $(obj),$(LIBBOARD))
# 	LIBBOARD = ./am335x/board/ti/am335x/libam335x.o
$(LIBBOARD):	depend $(LIBS)
		$(MAKE) -C $(dir $(subst $(obj),,$@))

#伪目标SUBDIRS: 执行tools ,examples ,post,post\cpu 子目录下面的make文件
$(SUBDIRS):	depend
		$(MAKE) -C $@ all

#LDSCRIPT = ./arch/arm/cpu/armv7/u-boot.lds	
#	其实就是把start.o和各个子目录makefile生成的库文件按照LDFLAGS连接在一起，
#	生成ELF文件u-boot 和连接时内存分配图文件u-boot.map。	
$(LDSCRIPT):	depend
		$(MAKE) -C $(dir $@) $(notdir $@)

$(obj)u-boot.lds: $(LDSCRIPT)
		$(CPP) $(CPPFLAGS) $(LDPPFLAGS) -ansi -D__ASSEMBLY__ -P - <$^ >$@

nand_spl:	$(TIMESTAMP_FILE) $(VERSION_FILE) depend
		$(MAKE) -C nand_spl/board/$(BOARDDIR) all

$(obj)u-boot-nand.bin:	nand_spl $(obj)u-boot.bin
		cat $(obj)nand_spl/u-boot-spl-16k.bin $(obj)u-boot.bin > $(obj)u-boot-nand.bin

onenand_ipl:	$(TIMESTAMP_FILE) $(VERSION_FILE) $(obj)include/autoconf.mk
		$(MAKE) -C onenand_ipl/board/$(BOARDDIR) all

$(obj)u-boot-onenand.bin:	onenand_ipl $(obj)u-boot.bin
		cat $(ONENAND_BIN) $(obj)u-boot.bin > $(obj)u-boot-onenand.bin

mmc_spl:	$(TIMESTAMP_FILE) $(VERSION_FILE) depend
		$(MAKE) -C mmc_spl/board/$(BOARDDIR) all

$(obj)mmc_spl/u-boot-mmc-spl.bin:	mmc_spl

$(obj)spl/u-boot-spl.bin:		depend
		$(MAKE) -C spl all

$(TIMESTAMP_FILE):
		@LC_ALL=C date +'#define U_BOOT_DATE "%b %d %C%y"' > $@
		@LC_ALL=C date +'#define U_BOOT_TIME "%T"' >> $@

updater:
		$(MAKE) -C tools/updater all

#########################################################################/*
#TIMESTAMP_FILE = $(obj)include/timestamp_autogenerated.h 	-> ./am335x/include/timestamp_autogenerated.h 
#VERSION_FILE 	= $(obj)include/version_autogenerated.h 	-> ./am335x/include/version_autogenerated.h
#obj			= ./am335x/
#SUBDIRS 		= tools examples/standalone examples/api
#CPUDIR			= CPUDIR = arch/$(ARCH)/cpu/$(CPU)			-> arch/arm/cpu/armv7
#LDSCRIPT		= $(TOPDIR)/$(CPUDIR)/u-boot.lds 			-> ./arch/arm/cpu/armv7/u-boot.lds
#	依赖目标depend :生成各个子目录的.depend文件，.depend列出每个目标文件的依赖文件。
# 	生成方法，调用每个子目录的	make _depend
#	对$(SUBDIRS) $(CPUDIR) $(LDSCRIPT_MAKEFILE_DIR)目录生成depend依赖文件;
#	而_depend是在uboot根目录下的rules.mk（./rules.mk）中定义的，利用CC的-M选项生成依赖文件.
# 注意： 所有的 .depend 文件都是隐藏文件。
#		当前所有的 .depend 文件都生成在 ./am335x 目录下的各个子目录中。
#########################################################################*/
# Explicitly make _depend in subdirs containing multiple targets to prevent
# parallel sub-makes creating .depend files simultaneously.
depend dep:	$(TIMESTAMP_FILE) $(VERSION_FILE) \
		$(obj)include/autoconf.mk \
		$(obj)include/generated/generic-asm-offsets.h \
		$(obj)include/generated/asm-offsets.h
		for dir in $(SUBDIRS) $(CPUDIR) $(dir $(LDSCRIPT)) ; do \
			$(MAKE) -C $$dir _depend ; done

TAG_SUBDIRS = $(SUBDIRS)
TAG_SUBDIRS += $(dir $(__LIBS))
TAG_SUBDIRS += include

FIND := find
FINDFLAGS := -L

tags ctags:
		ctags -w -o $(obj)ctags `$(FIND) $(FINDFLAGS) $(TAG_SUBDIRS) \
						-name '*.[chS]' -print`

etags:
		etags -a -o $(obj)etags `$(FIND) $(FINDFLAGS) $(TAG_SUBDIRS) \
						-name '*.[chS]' -print`
cscope:
		$(FIND) $(FINDFLAGS) $(TAG_SUBDIRS) -name '*.[chS]' -print > \
						cscope.files
		cscope -b -q -k

SYSTEM_MAP = \
		$(NM) $1 | \
		grep -v '\(compiled\)\|\(\.o$$\)\|\( [aUw] \)\|\(\.\.ng$$\)\|\(LASH[RL]DI\)' | \
		LC_ALL=C sort
$(obj)System.map:	$(obj)u-boot
		@$(call SYSTEM_MAP,$<) > $(obj)System.map

#
# Auto-generate the autoconf.mk file (which is included by all makefiles)
#
# This target actually generates 2 files; autoconf.mk and autoconf.mk.dep.
# the dep file is only include in this top level makefile to determine when
# to regenerate the autoconf.mk file.
$(obj)include/autoconf.mk.dep: $(obj)include/config.h include/common.h
	@$(XECHO) Generating $@ ; \
	set -e ; \
	: Generate the dependancies ; \
	$(CC) -x c -DDO_DEPS_ONLY -M $(HOSTCFLAGS) $(CPPFLAGS) \
		-MQ $(obj)include/autoconf.mk include/common.h > $@

#########################################################################/*
#	include/autoconf.mk依赖于make _config 命令生成的include/config.h。
#		因此执行make _config命令后再执行make all将更新include/autoconf.mk。
#
#	编译选项“-dM”的作用是输出include/common.h中定义的所有宏。
#		根据上面的规则，编译器提取include/common.h中定义的宏，
#		然后输出给tools/scripts/define2mk.sed脚本处理，处理的结果就是include/autoconf.mk文件。
#		其中tools/scripts/define2mk.sed脚本的主要完成了在include/common.h中查找和处理以“CONFIG_”开头的宏定义的功能。
#
#	include/common.h文件包含了include/config.h（./am335x/include/config.h）文件，
#		而include/config.h文件又包含了以下4 个文件：
#			#include 	位于： ./include/config_cmd_defaults.h
#			#include 		位于： ./include/config_defaults.h
#			#include 		位于： ./include/configs/am335x_evm.h
#			#include 				位于： ./arch/arm/include/asm/config.h
# 。因此include/autoconf.mk实质上就是以上5个文件中“CONFIG_”开头的有效的宏定义的集合。
#########################################################################*/
$(obj)include/autoconf.mk: $(obj)include/config.h
	@$(XECHO) Generating $@ ; \
	set -e ; \
	: Extract the config macros ; \
	$(CPP) $(CFLAGS) -DDO_DEPS_ONLY -dM include/common.h | \
		sed -n -f tools/scripts/define2mk.sed > $@.tmp && \
	mv $@.tmp $@

$(obj)include/generated/generic-asm-offsets.h:	$(obj)include/autoconf.mk.dep \
	$(obj)lib/asm-offsets.s
	@$(XECHO) Generating $@
	tools/scripts/make-asm-offsets $(obj)lib/asm-offsets.s $@

$(obj)lib/asm-offsets.s:	$(obj)include/autoconf.mk.dep \
	$(src)lib/asm-offsets.c
	@mkdir -p $(obj)lib
	$(CC) -DDO_DEPS_ONLY \
		$(CFLAGS) $(CFLAGS_$(BCURDIR)/$(@F)) $(CFLAGS_$(BCURDIR)) \
		-o $@ $(src)lib/asm-offsets.c -c -S

$(obj)include/generated/asm-offsets.h:	$(obj)include/autoconf.mk.dep \
	$(obj)$(CPUDIR)/$(SOC)/asm-offsets.s
	@echo Generating $@
	tools/scripts/make-asm-offsets $(obj)$(CPUDIR)/$(SOC)/asm-offsets.s $@

$(obj)$(CPUDIR)/$(SOC)/asm-offsets.s:	$(obj)include/autoconf.mk.dep
	@mkdir -p $(obj)$(CPUDIR)/$(SOC)
	if [ -f $(src)$(CPUDIR)/$(SOC)/asm-offsets.c ];then \
		$(CC) -DDO_DEPS_ONLY \
		$(CFLAGS) $(CFLAGS_$(BCURDIR)/$(@F)) $(CFLAGS_$(BCURDIR)) \
			-o $@ $(src)$(CPUDIR)/$(SOC)/asm-offsets.c -c -S; \
	else \
		touch $@; \
	fi

#########################################################################
else	# !config.mk ; ifeq ($(obj)include/config.mk,$(wildcard $(obj)include/config.mk))
all $(obj)u-boot.hex $(obj)u-boot.srec $(obj)u-boot.bin \
$(obj)u-boot.img $(obj)u-boot.dis $(obj)u-boot \
$(filter-out tools,$(SUBDIRS)) $(TIMESTAMP_FILE) \
updater depend dep tags ctags etags cscope $(obj)System.map:
	@echo "System not configured - see README" >&2
	@ exit 1

tools: $(VERSION_FILE)
	$(MAKE) -C $@ all
endif	# config.mk ; ifeq ($(obj)include/config.mk,$(wildcard $(obj)include/config.mk))

#生成版本信息到版本文件VERSION_FILE中
$(VERSION_FILE):
		@mkdir -p $(dir $(VERSION_FILE))
		@( localvers='$(shell $(TOPDIR)/tools/setlocalversion $(TOPDIR))' ; \
		   printf '#define PLAIN_VERSION "%s%s"\n' \
			"$(U_BOOT_VERSION)" "$${localvers}" ; \
		   printf '#define U_BOOT_VERSION "U-Boot %s%s"\n' \
			"$(U_BOOT_VERSION)" "$${localvers}" ; \
		) > $@.tmp
		@( printf '#define CC_VERSION_STRING "%s"\n' \
		 '$(shell $(CC) --version | head -n 1)' )>>  $@.tmp
		@( printf '#define LD_VERSION_STRING "%s"\n' \
		 '$(shell $(LD) -v | head -n 1)' )>>  $@.tmp
		@cmp -s $@ $@.tmp && rm -f $@.tmp || mv -f $@.tmp $@

easylogo env gdb:
	$(MAKE) -C tools/$@ all MTD_VERSION=${MTD_VERSION}
gdbtools: gdb

tools-all: easylogo env gdb $(VERSION_FILE)
	$(MAKE) -C tools HOST_TOOLS_ALL=y

.PHONY : CHANGELOG
CHANGELOG:
	git log --no-merges U-Boot-1_1_5.. | \
	unexpand -a | sed -e 's/\s\s*$$//' > $@

include/license.h: tools/bin2header COPYING
	cat COPYING | gzip -9 -c | ./tools/bin2header license_gzip > include/license.h
#########################################################################

unconfig:
	@rm -f $(obj)include/config.h $(obj)include/config.mk \
		$(obj)board/*/config.tmp $(obj)board/*/*/config.tmp \
		$(obj)include/autoconf.mk $(obj)include/autoconf.mk.dep

#########################################################################
#	%代表着任意字符
#%_config目标后面是双冒号，而我们平常看的只有一个冒号，这个就是makefile 的双冒号规则了，
#而平常我们见的单冒号就是普通规则。Makefile 中规定：一个目标可以出现在多个规则中。
#但是这些规则必须是同一类型的规则，要么都是普通规则，要么都是双冒号规则。
#而不允许一个目标同时出现在两种不同类型的规则中。双冒号规则和普通规则的处理的不同点表现在以下几个方面：
#1. 双冒号规则中，当依赖文件比目标更新时。规则将会被执行。对于一个没有依赖而只有命令行的双冒号规则，
#	当引用此目标时，规则的命令将会被无条件执行。而普通规则，当规则的目标文件存在时，
#	此规则的命令永远不会被执行（目标文件永远是最新的）。
#2. 当同一个文件作为多个双冒号规则的目标时。这些不同的规则会被独立的处理，
#	而不是像普通规则那样合并所有的依赖到一个目标文件。这就意味着对这些规则的处理就像多个不同
#	的普通规则一样。就是说多个双冒号规则中的每一个的依赖文件被改变之后，make只执行此规则定义的命令，
#	而其它的以这个文件作为目标的双冒号规则将不会被执行。

#@的作用是在执行这条命令的时候不进行显示，$(MKCONFIG)是取变量MKCONFIG，
#由MKCONFIG := $(SRCTREE)/mkconfig这条语句知，就是当前目录下的mkconfig文件，
#$(@:_config=)的意思是，讲目标文件名字中含有的_config用等号后面的的字符替换掉，
#这里＝后面为空，所以其效果就是把_config去掉
# 格式为“$(VAR:A=B)”(或者“${VAR:A=B}”),意思是:替换变量“VAR”中所有“A”字符结尾的字为“B”结尾的字。
#########################################################################
%_config::	unconfig
	@$(MKCONFIG) -A $(@:_config=)

#########################################################################
#读取uboot根目录下的 boards.cfg 文件生成 .boards.depend 隐藏文件，该文件位于 obj 目录下。
#########################################################################
sinclude $(obj).boards.depend
$(obj).boards.depend:	boards.cfg
	awk '(NF && $$1 !~ /^#/) { print $$1 ": " $$1 "_config; $$(MAKE)" }' $< > $@

#
# Functions to generate common board directory names
#
lcname	= $(shell echo $(1) | sed -e 's/\(.*\)_config/\L\1/')
ucname	= $(shell echo $(1) | sed -e 's/\(.*\)_config/\U\1/')

#########################################################################
## Coldfire
#########################################################################

astro_mcf5373l_config \
astro_mcf5373l_RAM_config :	unconfig
	@$(MKCONFIG) -n $@ -t $@ astro_mcf5373l m68k mcf532x mcf5373l astro

M52277EVB_config \
M52277EVB_spansion_config \
M52277EVB_stmicro_config :	unconfig
	@case "$@" in \
	M52277EVB_config)		FLASH=SPANSION;; \
	M52277EVB_spansion_config)	FLASH=SPANSION;; \
	M52277EVB_stmicro_config)	FLASH=STMICRO;; \
	esac; \
	if [ "$${FLASH}" = "SPANSION" ] ; then \
		echo "#define CONFIG_SYS_SPANSION_BOOT"	>> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x00000000" > $(obj)board/freescale/m52277evb/config.tmp ; \
		cp $(obj)board/freescale/m52277evb/u-boot.spa $(obj)board/freescale/m52277evb/u-boot.lds ; \
	fi; \
	if [ "$${FLASH}" = "STMICRO" ] ; then \
		echo "#define CONFIG_CF_SBF"	>> $(obj)include/config.h ; \
		echo "#define CONFIG_SYS_STMICRO_BOOT"	>> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x43E00000" > $(obj)board/freescale/m52277evb/config.tmp ; \
		cp $(obj)board/freescale/m52277evb/u-boot.stm $(obj)board/freescale/m52277evb/u-boot.lds ; \
	fi
	@$(MKCONFIG) -n $@ -a M52277EVB m68k mcf5227x m52277evb freescale

M5235EVB_config \
M5235EVB_Flash16_config \
M5235EVB_Flash32_config:	unconfig
	@case "$@" in \
	M5235EVB_config)		FLASH=16;; \
	M5235EVB_Flash16_config)	FLASH=16;; \
	M5235EVB_Flash32_config)	FLASH=32;; \
	esac; \
	if [ "$${FLASH}" != "16" ] ; then \
		echo "#define NORFLASH_PS32BIT	1" >> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0xFFC00000" > $(obj)board/freescale/m5235evb/config.tmp ; \
		cp $(obj)board/freescale/m5235evb/u-boot.32 $(obj)board/freescale/m5235evb/u-boot.lds ; \
	else \
		echo "CONFIG_SYS_TEXT_BASE = 0xFFE00000" > $(obj)board/freescale/m5235evb/config.tmp ; \
		cp $(obj)board/freescale/m5235evb/u-boot.16 $(obj)board/freescale/m5235evb/u-boot.lds ; \
	fi
	@$(MKCONFIG) -n $@ -a M5235EVB m68k mcf523x m5235evb freescale

cobra5272_config :		unconfig
	@$(MKCONFIG) $@ m68k mcf52x2 cobra5272

EB+MCF-EV123_config :		unconfig
	@mkdir -p $(obj)include
	@mkdir -p $(obj)board/BuS/EB+MCF-EV123
	@echo "CONFIG_SYS_TEXT_BASE = 0xFFE00000"|tee $(obj)board/BuS/EB+MCF-EV123/textbase.mk
	@$(MKCONFIG) -n $@ EB+MCF-EV123 m68k mcf52x2 EB+MCF-EV123 BuS

EB+MCF-EV123_internal_config :	unconfig
	@mkdir -p $(obj)include
	@mkdir -p $(obj)board/BuS/EB+MCF-EV123
	@echo "CONFIG_SYS_TEXT_BASE = 0xF0000000"|tee $(obj)board/BuS/EB+MCF-EV123/textbase.mk
	@$(MKCONFIG) -n $@ EB+MCF-EV123 m68k mcf52x2 EB+MCF-EV123 BuS

M5329AFEE_config \
M5329BFEE_config :	unconfig
	@case "$@" in \
	M5329AFEE_config)	NAND=0;; \
	M5329BFEE_config)	NAND=16;; \
	esac; \
	if [ "$${NAND}" != "0" ] ; then \
		echo "#define NANDFLASH_SIZE	$${NAND}" > $(obj)include/config.h ; \
	fi
	@$(MKCONFIG) -n $@ -a M5329EVB m68k mcf532x m5329evb freescale

M5373EVB_config :	unconfig
	@case "$@" in \
	M5373EVB_config)	NAND=16;; \
	esac; \
	if [ "$${NAND}" != "0" ] ; then \
		echo "#define NANDFLASH_SIZE	$${NAND}" > $(obj)include/config.h ; \
	fi
	@$(MKCONFIG) -a M5373EVB m68k mcf532x m5373evb freescale

M54451EVB_config \
M54451EVB_stmicro_config :	unconfig
	@case "$@" in \
	M54451EVB_config)		FLASH=NOR;; \
	M54451EVB_stmicro_config)	FLASH=STMICRO;; \
	esac; \
	if [ "$${FLASH}" = "NOR" ] ; then \
		echo "CONFIG_SYS_TEXT_BASE = 0x00000000" > $(obj)board/freescale/m54451evb/config.tmp ; \
		cp $(obj)board/freescale/m54451evb/u-boot.spa $(obj)board/freescale/m54451evb/u-boot.lds ; \
	fi; \
	if [ "$${FLASH}" = "STMICRO" ] ; then \
		echo "#define CONFIG_CF_SBF"	>> $(obj)include/config.h ; \
		echo "#define CONFIG_SYS_STMICRO_BOOT"	>> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x47E00000" > $(obj)board/freescale/m54451evb/config.tmp ; \
		cp $(obj)board/freescale/m54451evb/u-boot.stm $(obj)board/freescale/m54451evb/u-boot.lds ; \
	fi; \
	echo "#define CONFIG_SYS_INPUT_CLKSRC 24000000" >> $(obj)include/config.h ;
	@$(MKCONFIG) -n $@ -a M54451EVB m68k mcf5445x m54451evb freescale

M54455EVB_config \
M54455EVB_atmel_config \
M54455EVB_intel_config \
M54455EVB_a33_config \
M54455EVB_a66_config \
M54455EVB_i33_config \
M54455EVB_i66_config \
M54455EVB_stm33_config :	unconfig
	@case "$@" in \
	M54455EVB_config)		FLASH=ATMEL; FREQ=33333333;; \
	M54455EVB_atmel_config)		FLASH=ATMEL; FREQ=33333333;; \
	M54455EVB_intel_config)		FLASH=INTEL; FREQ=33333333;; \
	M54455EVB_a33_config)		FLASH=ATMEL; FREQ=33333333;; \
	M54455EVB_a66_config)		FLASH=ATMEL; FREQ=66666666;; \
	M54455EVB_i33_config)		FLASH=INTEL; FREQ=33333333;; \
	M54455EVB_i66_config)		FLASH=INTEL; FREQ=66666666;; \
	M54455EVB_stm33_config)		FLASH=STMICRO; FREQ=33333333;; \
	esac; \
	if [ "$${FLASH}" = "INTEL" ] ; then \
		echo "#define CONFIG_SYS_INTEL_BOOT" >> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x00000000" > $(obj)board/freescale/m54455evb/config.tmp ; \
		cp $(obj)board/freescale/m54455evb/u-boot.int $(obj)board/freescale/m54455evb/u-boot.lds ; \
	fi; \
	if [ "$${FLASH}" = "ATMEL" ] ; then \
		echo "#define CONFIG_SYS_ATMEL_BOOT"	>> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x04000000" > $(obj)board/freescale/m54455evb/config.tmp ; \
		cp $(obj)board/freescale/m54455evb/u-boot.atm $(obj)board/freescale/m54455evb/u-boot.lds ; \
	fi; \
	if [ "$${FLASH}" = "STMICRO" ] ; then \
		echo "#define CONFIG_CF_SBF"	>> $(obj)include/config.h ; \
		echo "#define CONFIG_SYS_STMICRO_BOOT"	>> $(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x4FE00000" > $(obj)board/freescale/m54455evb/config.tmp ; \
		cp $(obj)board/freescale/m54455evb/u-boot.stm $(obj)board/freescale/m54455evb/u-boot.lds ; \
	fi; \
	echo "#define CONFIG_SYS_INPUT_CLKSRC $${FREQ}" >> $(obj)include/config.h ; \
	$(XECHO) "... with $${FREQ}Hz input clock"
	@$(MKCONFIG) -n $@ -a M54455EVB m68k mcf5445x m54455evb freescale

M5475AFE_config \
M5475BFE_config \
M5475CFE_config \
M5475DFE_config \
M5475EFE_config \
M5475FFE_config \
M5475GFE_config :	unconfig
	@case "$@" in \
	M5475AFE_config)	BOOT=2;CODE=0;VID=0;USB=0;RAM=64;RAM1=0;; \
	M5475BFE_config)	BOOT=2;CODE=16;VID=0;USB=0;RAM=64;RAM1=0;; \
	M5475CFE_config)	BOOT=2;CODE=16;VID=1;USB=1;RAM=64;RAM1=0;; \
	M5475DFE_config)	BOOT=2;CODE=0;VID=0;USB=1;RAM=64;RAM1=0;; \
	M5475EFE_config)	BOOT=2;CODE=0;VID=1;USB=1;RAM=64;RAM1=0;; \
	M5475FFE_config)	BOOT=2;CODE=32;VID=1;USB=1;RAM=64;RAM1=64;; \
	M5475GFE_config)	BOOT=4;CODE=0;VID=0;USB=0;RAM=64;RAM1=0;; \
	esac; \
	echo "#define CONFIG_SYS_BUSCLK	133333333" > $(obj)include/config.h ; \
	echo "#define CONFIG_SYS_BOOTSZ	$${BOOT}" >> $(obj)include/config.h ; \
	echo "#define CONFIG_SYS_DRAMSZ	$${RAM}" >> $(obj)include/config.h ; \
	if [ "$${RAM1}" != "0" ] ; then \
		echo "#define CONFIG_SYS_DRAMSZ1	$${RAM1}" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${CODE}" != "0" ] ; then \
		echo "#define CONFIG_SYS_NOR1SZ	$${CODE}" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${VID}" == "1" ] ; then \
		echo "#define CONFIG_SYS_VIDEO" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${USB}" == "1" ] ; then \
		echo "#define CONFIG_SYS_USBCTRL" >> $(obj)include/config.h ; \
	fi
	@$(MKCONFIG) -n $@ -a M5475EVB m68k mcf547x_8x m547xevb freescale

M5485AFE_config \
M5485BFE_config \
M5485CFE_config \
M5485DFE_config \
M5485EFE_config \
M5485FFE_config \
M5485GFE_config \
M5485HFE_config :	unconfig
	@case "$@" in \
	M5485AFE_config)	BOOT=2;CODE=0;VID=0;USB=0;RAM=64;RAM1=0;; \
	M5485BFE_config)	BOOT=2;CODE=16;VID=0;USB=0;RAM=64;RAM1=0;; \
	M5485CFE_config)	BOOT=2;CODE=16;VID=1;USB=1;RAM=64;RAM1=0;; \
	M5485DFE_config)	BOOT=2;CODE=0;VID=0;USB=1;RAM=64;RAM1=0;; \
	M5485EFE_config)	BOOT=2;CODE=0;VID=1;USB=1;RAM=64;RAM1=0;; \
	M5485FFE_config)	BOOT=2;CODE=32;VID=1;USB=1;RAM=64;RAM1=64;; \
	M5485GFE_config)	BOOT=4;CODE=0;VID=0;USB=0;RAM=64;RAM1=0;; \
	M5485HFE_config)	BOOT=2;CODE=16;VID=1;USB=0;RAM=64;RAM1=0;; \
	esac; \
	echo "#define CONFIG_SYS_BUSCLK	100000000" > $(obj)include/config.h ; \
	echo "#define CONFIG_SYS_BOOTSZ	$${BOOT}" >> $(obj)include/config.h ; \
	echo "#define CONFIG_SYS_DRAMSZ	$${RAM}" >> $(obj)include/config.h ; \
	if [ "$${RAM1}" != "0" ] ; then \
		echo "#define CONFIG_SYS_DRAMSZ1	$${RAM1}" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${CODE}" != "0" ] ; then \
		echo "#define CONFIG_SYS_NOR1SZ	$${CODE}" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${VID}" == "1" ] ; then \
		echo "#define CONFIG_SYS_VIDEO" >> $(obj)include/config.h ; \
	fi; \
	if [ "$${USB}" == "1" ] ; then \
		echo "#define CONFIG_SYS_USBCTRL" >> $(obj)include/config.h ; \
	fi
	@$(MKCONFIG) -n $@ -a M5485EVB m68k mcf547x_8x m548xevb freescale

#========================================================================
# ARM
#========================================================================

xtract_omap1610xxx = $(subst _cs0boot,,$(subst _cs3boot,,$(subst _cs_autoboot,,$(subst _config,,$1))))

omap1610inn_config \
omap1610inn_cs0boot_config \
omap1610inn_cs3boot_config \
omap1610inn_cs_autoboot_config \
omap1610h2_config \
omap1610h2_cs0boot_config \
omap1610h2_cs3boot_config \
omap1610h2_cs_autoboot_config:	unconfig
	@mkdir -p $(obj)include
	@if [ "$(findstring _cs0boot_, $@)" ] ; then \
		echo "#define CONFIG_CS0_BOOT" >> .$(obj)include/config.h ; \
	elif [ "$(findstring _cs_autoboot_, $@)" ] ; then \
		echo "#define CONFIG_CS_AUTOBOOT" >> $(obj)include/config.h ; \
	else \
		echo "#define CONFIG_CS3_BOOT" >> $(obj)include/config.h ; \
	fi;
	@$(MKCONFIG) -n $@ -a $(call xtract_omap1610xxx,$@) arm arm926ejs omap1610inn ti omap

omap730p2_config \
omap730p2_cs0boot_config \
omap730p2_cs3boot_config :	unconfig
	@mkdir -p $(obj)include
	@if [ "$(findstring _cs0boot_, $@)" ] ; then \
		echo "#define CONFIG_CS0_BOOT" >> $(obj)include/config.h ; \
	else \
		echo "#define CONFIG_CS3_BOOT" >> $(obj)include/config.h ; \
	fi;
	@$(MKCONFIG) -n $@ -a omap730p2 arm arm926ejs omap730p2 ti omap

spear300_config \
spear310_config \
spear320_config :	unconfig
	@$(MKCONFIG) -n $@ -t $@ spear3xx arm arm926ejs $(@:_config=) spear spear

spear600_config :	unconfig
	@$(MKCONFIG) -n $@ -t $@ spear6xx arm arm926ejs $(@:_config=) spear spear

SX1_stdout_serial_config \
SX1_config:		unconfig
	@mkdir -p $(obj)include
	@if [ "$(findstring _stdout_serial_, $@)" ] ; then \
		echo "#undef CONFIG_STDOUT_USBTTY" >> $(obj)include/config.h ; \
	else \
		echo "#define CONFIG_STDOUT_USBTTY" >> $(obj)include/config.h ; \
	fi;
	@$(MKCONFIG) -n $@ SX1 arm arm925t sx1

tx25_config	: unconfig
	@echo "CONFIG_NAND_U_BOOT = y" >> $(obj)include/config.mk
	@$(MKCONFIG) $@ arm arm926ejs tx25 karo mx25

ti8168_evm_config	\
ti8168_evm_config_nand	\
ti8168_evm_config_nor	\
ti8168_evm_config_spi	\
ti8168_evm_min_ocmc	\
ti8168_evm_min_sd:	unconfig
	@mkdir -p $(obj)include
	@echo "#define CONFIG_TI81XX"	>>$(obj)include/config.h
	@echo "#define CONFIG_TI816X"	>>$(obj)include/config.h
	@if [ "$(findstring _nand,$@)" ] ; then \
		echo "#define CONFIG_SYS_NO_FLASH"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_NAND_ENV"    >>$(obj)include/config.h ; \
		echo "Setting up TI8168 NAND build with ENV in NAND..." ; \
	elif [ "$(findstring _nor,$@)" ] ; then \
		echo "#define CONFIG_NOR"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_NOR_BOOT"	>>$(obj)include/config.h ; \
		echo "Setting up TI8168 NOR build with ENV in NOR..." ; \
	elif [ "$(findstring _spi,$@)" ] ; then \
		echo "#define CONFIG_SYS_NO_FLASH"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_SPI_ENV"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_TI81XX_SPI_BOOT"	>>$(obj)include/config.h ; \
		echo "Setting up TI8168 SPI build with ENV in SPI..." ; \
	elif [ "$(findstring _sd,$@)" ] ; then \
		echo "#define CONFIG_SYS_NO_FLASH"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_SD_BOOT"    >>$(obj)include/config.h ; \
		echo "TI_IMAGE = u-boot.min.sd" >>$(obj)board/ti/ti8168/config.tmp; \
		echo "Setting up TI8168 SD boot minimal build..." ; \
	elif [ "$(findstring _ocmc,$@)" ] ; then \
		echo "#define CONFIG_SYS_NO_FLASH"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_MINIMAL"    >>$(obj)include/config.h ; \
		echo "CONFIG_SYS_TEXT_BASE = 0x40410000" >>$(obj)board/ti/ti8168/config.tmp; \
		echo "Setting up TI8168 minimal build..." ; \
	else	\
		echo "#define CONFIG_SYS_NO_FLASH"    >>$(obj)include/config.h ; \
		echo "#define CONFIG_NAND_ENV"    >>$(obj)include/config.h ; \
		echo "Setting up TI8168 default build with NAND..." ; \
	fi;
	@$(MKCONFIG) -a ti8168_evm arm armv7 ti8168 ti ti81xx

#########################################################################
## XScale Systems
#########################################################################

pdnb3_config \
scpu_config:	unconfig
	@mkdir -p $(obj)include
	@if [ "$(findstring scpu_,$@)" ] ; then \
		echo "#define CONFIG_SCPU"	>>$(obj)include/config.h ; \
	fi
	@$(MKCONFIG) -n $@ -a pdnb3 arm ixp pdnb3 prodrive

#########################################################################
## ARM1136 Systems
#########################################################################

apollon_config		: unconfig
	@mkdir -p $(obj)include
	@echo "#define CONFIG_ONENAND_U_BOOT" > $(obj)include/config.h
	@echo "CONFIG_ONENAND_U_BOOT = y" >> $(obj)include/config.mk
	@$(MKCONFIG) $@ arm arm1136 apollon - omap24xx

imx31_phycore_eet_config \
imx31_phycore_config	: unconfig
	@mkdir -p $(obj)include
	@if [ -n "$(findstring _eet_,$@)" ]; then			\
		echo "#define CONFIG_IMX31_PHYCORE_EET" >> $(obj)include/config.h;	\
	fi
	@$(MKCONFIG) -n $@ -a imx31_phycore arm arm1136 imx31_phycore - mx31

mx31pdk_config \
mx31pdk_nand_config	: unconfig
	@mkdir -p $(obj)include
	@if [ -n "$(findstring _nand_,$@)" ]; then					\
		echo "#define CONFIG_NAND_U_BOOT" >> $(obj)include/config.h;		\
	else										\
		echo "#define CONFIG_SKIP_LOWLEVEL_INIT" >> $(obj)include/config.h;	\
	fi
	@$(MKCONFIG) -n $@ -a mx31pdk arm arm1136 mx31pdk freescale mx31

#########################################################################
## ARM1176 Systems
#########################################################################
smdk6400_noUSB_config	\
smdk6400_config	:	unconfig
	@mkdir -p $(obj)include $(obj)board/samsung/smdk6400
	@mkdir -p $(obj)nand_spl/board/samsung/smdk6400
	@echo "#define CONFIG_NAND_U_BOOT" > $(obj)include/config.h
	@echo "CONFIG_NAND_U_BOOT = y" >> $(obj)include/config.mk
	@if [ -z "$(findstring smdk6400_noUSB_config,$@)" ]; then			\
		echo "RAM_TEXT = 0x57e00000" >> $(obj)board/samsung/smdk6400/config.tmp;\
	else										\
		echo "RAM_TEXT = 0xc7e00000" >> $(obj)board/samsung/smdk6400/config.tmp;\
	fi
	@$(MKCONFIG) smdk6400 arm arm1176 smdk6400 samsung s3c64xx
	@echo "CONFIG_NAND_U_BOOT = y" >> $(obj)include/config.mk

#########################################################################
#########################################################################

clean:
	@rm -f $(obj)examples/standalone/82559_eeprom			  \
	       $(obj)examples/standalone/atmel_df_pow2			  \
	       $(obj)examples/standalone/eepro100_eeprom		  \
	       $(obj)examples/standalone/hello_world			  \
	       $(obj)examples/standalone/interrupt			  \
	       $(obj)examples/standalone/mem_to_mem_idma2intr		  \
	       $(obj)examples/standalone/sched				  \
	       $(obj)examples/standalone/smc911{11,x}_eeprom		  \
	       $(obj)examples/standalone/test_burst			  \
	       $(obj)examples/standalone/timer
	@rm -f $(obj)examples/api/demo{,.bin}
	@rm -f $(obj)tools/bmp_logo	   $(obj)tools/easylogo/easylogo  \
	       $(obj)tools/env/{fw_printenv,fw_setenv}			  \
	       $(obj)tools/envcrc					  \
	       $(obj)tools/gdb/{astest,gdbcont,gdbsend}			  \
	       $(obj)tools/gen_eth_addr    $(obj)tools/img2srec		  \
	       $(obj)tools/mkimage	   $(obj)tools/mpc86x_clk	  \
	       $(obj)tools/ncb		   $(obj)tools/ubsha1
	@rm -f $(obj)board/cray/L1/{bootscript.c,bootscript.image}	  \
	       $(obj)board/matrix_vision/*/bootscript.img		  \
	       $(obj)board/voiceblue/eeprom 				  \
	       $(obj)u-boot.lds						  \
	       $(obj)arch/blackfin/cpu/bootrom-asm-offsets.[chs]	  \
	       $(obj)arch/blackfin/cpu/init.{lds,elf}
	@rm -f $(obj)include/bmp_logo.h
	@rm -f $(obj)lib/asm-offsets.s
	@rm -f $(obj)include/generated/asm-offsets.h
	@rm -f $(obj)$(CPUDIR)/$(SOC)/asm-offsets.s
	@rm -f $(obj)nand_spl/{u-boot.lds,u-boot-nand_spl.lds,u-boot-spl,u-boot-spl.map,System.map}
	@rm -f $(obj)onenand_ipl/onenand-{ipl,ipl.bin,ipl.map}
	@rm -f $(obj)mmc_spl/{u-boot.lds,u-boot-spl,u-boot-spl.map,u-boot-spl.bin,u-boot-mmc-spl.bin}
	@rm -f $(ONENAND_BIN)
	@rm -f $(obj)onenand_ipl/u-boot.lds
	@rm -f $(obj)spl/{u-boot-spl,u-boot-spl.bin,u-boot-spl.lds,u-boot-spl.map}
	@rm -f $(TIMESTAMP_FILE) $(VERSION_FILE)
	@find $(OBJTREE) -type f \
		\( -name 'core' -o -name '*.bak' -o -name '*~' \
		-o -name '*.o'	-o -name '*.a' -o -name '*.exe'	\) -print \
		| xargs rm -f

clobber:	clean
	@find $(OBJTREE) -type f \( -name '*.depend' \
		-o -name '*.srec' -o -name '*.bin' -o -name u-boot.img \) \
		-print0 \
		| xargs -0 rm -f
	@rm -f $(OBJS) $(obj)*.bak $(obj)ctags $(obj)etags $(obj)TAGS \
		$(obj)cscope.* $(obj)*.*~
	@rm -f $(obj)u-boot $(obj)u-boot.map $(obj)u-boot.hex $(ALL-y)
	@rm -f $(obj)u-boot.kwb
	@rm -f $(obj)u-boot.imx
	@rm -f $(obj)u-boot.ubl
	@rm -f $(obj)tools/{env/crc32.c,inca-swap-bytes}
	@rm -f $(obj)arch/powerpc/cpu/mpc824x/bedbug_603e.c
	@rm -fr $(obj)include/asm/proc $(obj)include/asm/arch $(obj)include/asm
	@rm -fr $(obj)include/generated
	@[ ! -d $(obj)nand_spl ] || find $(obj)nand_spl -name "*" -type l -print | xargs rm -f
	@[ ! -d $(obj)onenand_ipl ] || find $(obj)onenand_ipl -name "*" -type l -print | xargs rm -f
	@[ ! -d $(obj)mmc_spl ] || find $(obj)mmc_spl -name "*" -type l -print | xargs rm -f

mrproper \
distclean:	clobber unconfig
ifneq ($(OBJTREE),$(SRCTREE))
	rm -rf $(obj)*
endif

backup:
	F=`basename $(TOPDIR)` ; cd .. ; \
	gtar --force-local -zcvf `LC_ALL=C date "+$$F-%Y-%m-%d-%T.tar.gz"` $$F

#########################################################################



config.mk 详解： 


#
# (C) Copyright 2000-2006
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
#
# See file CREDITS for list of people who contributed to this
# project.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of
# the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
# MA 02111-1307 USA
#

#########################################################################
#当前 	CURDIR 	= ./
#		SRCTREE = ./
#则 dir 为空
#########################################################################
ifeq ($(CURDIR),$(SRCTREE))
dir :=
else
dir := $(subst $(SRCTREE)/,,$(CURDIR))
endif

#########################################################################
#当前 	OBJTREE = ./am335x
#		SRCTREE = ./
#判断变量OBJTREE,SRCTREE是否相等,其不相同，则条件为真
#查找CONFIG_SPL_BUILD是否定义为y，在autoconf.mk(./am335x/include/autoconf.mk)中,并没有这个定义 
#则  obj := $(if $(dir),$(OBJTREE)/$(dir)/,$(OBJTREE)/) -> 	obj = ./am335x/
#	src = ./
# dir 为空
# SPLTREE 为 ./am335x/spl
# 然后创建 ./am335x 目录
## -p 表示如果目录已存在，并不会产生错误
#########################################################################
ifneq ($(OBJTREE),$(SRCTREE))
# Create object files for SPL in a separate directory
ifeq ($(CONFIG_SPL_BUILD),y)
obj := $(if $(dir),$(SPLTREE)/$(dir)/,$(SPLTREE)/)
else
obj := $(if $(dir),$(OBJTREE)/$(dir)/,$(OBJTREE)/)
endif
src := $(if $(dir),$(SRCTREE)/$(dir)/,$(SRCTREE)/)

$(shell mkdir -p $(obj))
else
# Create object files for SPL in a separate directory
ifeq ($(CONFIG_SPL_BUILD),y)
obj := $(if $(dir),$(SPLTREE)/$(dir)/,$(SPLTREE)/)

$(shell mkdir -p $(obj))
else
obj :=
endif
src :=
endif

# clean the slate ...
PLATFORM_RELFLAGS =
PLATFORM_CPPFLAGS =
PLATFORM_LDFLAGS =

#########################################################################

HOSTCFLAGS	= -Wall -Wstrict-prototypes -O2 -fomit-frame-pointer \
		  $(HOSTCPPFLAGS)
HOSTSTRIP	= strip

#
# Mac OS X / Darwin's C preprocessor is Apple specific.  It
# generates numerous errors and warnings.  We want to bypass it
# and use GNU C's cpp.	To do this we pass the -traditional-cpp
# option to the compiler.  Note that the -traditional-cpp flag
# DOES NOT have the same semantics as GNU C's flag, all it does
# is invoke the GNU preprocessor in stock ANSI/ISO C fashion.
#
# Apple's linker is similar, thanks to the new 2 stage linking
# multiple symbol definitions are treated as errors, hence the
# -multiply_defined suppress option to turn off this error.
#
#当前 HOSTOS 为linux,条件为假，不执行条件中的代码
#得 HOSTCC		= gcc
ifeq ($(HOSTOS),darwin)
# get major and minor product version (e.g. '10' and '6' for Snow Leopard)
DARWIN_MAJOR_VERSION	= $(shell sw_vers -productVersion | cut -f 1 -d '.')
DARWIN_MINOR_VERSION	= $(shell sw_vers -productVersion | cut -f 2 -d '.')

os_x_before	= $(shell if [ $(DARWIN_MAJOR_VERSION) -le $(1) -a \
	$(DARWIN_MINOR_VERSION) -le $(2) ] ; then echo "$(3)"; else echo "$(4)"; fi ;)

# Snow Leopards build environment has no longer restrictions as described above
HOSTCC		 = $(call os_x_before, 10, 5, "cc", "gcc")
HOSTCFLAGS	+= $(call os_x_before, 10, 4, "-traditional-cpp")
HOSTLDFLAGS	+= $(call os_x_before, 10, 5, "-multiply_defined suppress")
else
HOSTCC		= gcc
endif

#当前 HOSTOS 为linux,条件为假，不执行条件中的代码
ifeq ($(HOSTOS),cygwin)
HOSTCFLAGS	+= -ansi
endif

# We build some files with extra pedantic flags to try to minimize things
# that won't build on some weird host compiler -- though there are lots of
# exceptions for files that aren't complaint.
#########################################################################
#HOSTCFLAGS_NOPED是利用filter-out函数从HOSTCFLAGS中过滤掉-pedantic选项    
#而HOSTCFLAGS追加上-pedantic选项 
#########################################################################
HOSTCFLAGS_NOPED = $(filter-out -pedantic,$(HOSTCFLAGS))
HOSTCFLAGS	+= -pedantic

#########################################################################
#
# Option checker (courtesy linux kernel) to ensure
# only supported compiler options are used
#
#########################################################################
#CC = $(CROSS_COMPILE)gcc 
#CROSS_COMPILE = arm-arago-linux-gnueabi-
#CC = arm-arago-linux-gnueabi-gcc
# 函数 cc-option = $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null > /dev/null 2>&1; then echo "$(1)"; 
#########################################################################
cc-option = $(shell if $(CC) $(CFLAGS) $(1) -S -o /dev/null -xc /dev/null \
		> /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)

#
# Include the make variables (CC, etc...)
#
AS	= $(CROSS_COMPILE)as
LD	= $(CROSS_COMPILE)ld
CC	= $(CROSS_COMPILE)gcc
CPP	= $(CC) -E
AR	= $(CROSS_COMPILE)ar
NM	= $(CROSS_COMPILE)nm
LDR	= $(CROSS_COMPILE)ldr
STRIP	= $(CROSS_COMPILE)strip
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
RANLIB	= $(CROSS_COMPILE)RANLIB

#########################################################################
#包含文件 	./am335x/include/autoconf.mk,编译时需要用到的一些宏定义;
#			./am335x/include/config.mk,开发板的相关信息
sinclude $(OBJTREE)/include/autoconf.mk
sinclude $(OBJTREE)/include/config.mk

# Some architecture config.mk files need to know what CPUDIR is set to,
# so calculate CPUDIR before including ARCH/SOC/CPU config.mk files.
# Check if arch/$ARCH/cpu/$CPU exists, otherwise assume arch/$ARCH/cpu contains
# CPU-specific code.
#########################################################################/*
#	ARCH	= arm
#	CPU		= armv7
# 得CPUDIR	= arch/arm/cpu/armv7
#########################################################################*/
CPUDIR=arch/$(ARCH)/cpu/$(CPU)

#########################################################################/*
#	SRCTREE	= ./( uboot的根目录)
#	$(SRCTREE)/$(CPUDIR) = ./arch/arm/cpu/armv7
#存在该目录，条件为假，条件中的代码不会被执行
#########################################################################*/
ifneq ($(SRCTREE)/$(CPUDIR),$(wildcard $(SRCTREE)/$(CPUDIR)))
CPUDIR=arch/$(ARCH)/cpu
endif

#########################################################################/*
#	TOPDIR	= ./( uboot的根目录)
#	ARCH	= arm
#	CPUDIR  = arch/arm/cpu/armv7
#包含文件 $(TOPDIR)/arch/$(ARCH)/config.mk 	-> ./arch/arm/config.mk
#包含文件 $(TOPDIR)/$(CPUDIR)/config.mk 		-> ./arch/arm/cpu/armv7/config.mk
#########################################################################*/
sinclude $(TOPDIR)/arch/$(ARCH)/config.mk	# include architecture dependend rules
sinclude $(TOPDIR)/$(CPUDIR)/config.mk		# include  CPU	specific rules

#########################################################################/*
#判断是否定义了 SOC，当前 SOC 为 ti81xx，条件为 真，
#则包含文件 $(TOPDIR)/$(CPUDIR)/$(SOC)/config.mk -> ./arch/arm/cpu/armv7/ti81xx/config.mk
#	TOPDIR	= ./( uboot的根目录)
#	SOC		= ti81xx
#	CPUDIR  = arch/arm/cpu/armv7
#########################################################################*/
ifdef	SOC
sinclude $(TOPDIR)/$(CPUDIR)/$(SOC)/config.mk	# include  SoC	specific rules
endif

#########################################################################/*
#判断是否定义了 VENDOR，当前 VENDOR 为 ti，条件为 真，
#则得 BOARDDIR = ti/am335x
#	VENDOR	= ti
#	BOARD	= am335x
#########################################################################*/
ifdef	VENDOR
BOARDDIR = $(VENDOR)/$(BOARD)
else
BOARDDIR = $(BOARD)
endif

#########################################################################/*
#判断是否定义了 BOARD，当前 BOARD 为 am335x，条件为 真，
#则得 BOARDDIR = ti/am335x
#	BOARD	= am335x
#	TOPDIR	= ./( uboot的根目录)
#包含文件 $(TOPDIR)/board/$(BOARDDIR)/config.mk 	-> ./board/ti/am335x/config.mk
# !!!但是找不到相应的文件!!!
#########################################################################*/
ifdef	BOARD
sinclude $(TOPDIR)/board/$(BOARDDIR)/config.mk	# include board specific rules
endif

#########################################################################
#########################################################################/*
#	MAKEFLAGS 		= wp -- $(MAKEOVERRIDES)
#	MAKEOVERRIDES 	= ${-*-command-variables-*-}
#	-*-command-variables-*- := O=am335x
#判断字符串 s 是否为空, s = O=am335x,s不为空,条件为假，则 ARFLAGS = crv
#########################################################################*/
ifneq (,$(findstring s,$(MAKEFLAGS)))
ARFLAGS = cr
else
ARFLAGS = crv
endif

#PLATFORM_RELFLAGS =  -fno-common -ffixed-r8 -msoft-float $(call cc-option,-mshort-load-bytes, $(call cc-option,-malignment-traps,))
RELFLAGS= $(PLATFORM_RELFLAGS)
DBGFLAGS= -g # -DDEBUG
OPTFLAGS= -Os #-fomit-frame-pointer

OBJCFLAGS += --gap-fill=0xff

#gccincdir = arm-arago-linux-gnueabi-gcc -print-file-name=include
gccincdir := $(shell $(CC) -print-file-name=include)

#CPPFLAGS = -g  -Os   -fno-common -ffixed-r8 -msoft-float   -D__KERNEL__ 
CPPFLAGS := $(DBGFLAGS) $(OPTFLAGS) $(RELFLAGS)		\
	-D__KERNEL__

# Enable garbage collection of un-used sections for SPL
#########################################################################/*
#CONFIG_SPL_BUILD = y
#判断 CONFIG_SPL_BUILD 是否为 y，而 CONFIG_SPL_BUILD=y，条件为真，执行条件下的代码
#########################################################################*/
ifeq ($(CONFIG_SPL_BUILD),y)
CPPFLAGS += -ffunction-sections -fdata-sections
LDFLAGS_FINAL += --gc-sections
endif

#########################################################################/*
#CONFIG_SYS_TEXT_BASE=0x80800000
#判断 CONFIG_SYS_TEXT_BASE 是否为空，而 CONFIG_SYS_TEXT_BASE=0x80800000，条件为真，执行条件下的代码
#########################################################################*/
ifneq ($(CONFIG_SYS_TEXT_BASE),)
CPPFLAGS += -DCONFIG_SYS_TEXT_BASE=$(CONFIG_SYS_TEXT_BASE)
endif

#########################################################################/*
#CONFIG_SPL_TEXT_BASE=0x402F0400
#判断 CONFIG_SPL_TEXT_BASE 是否为空，而 CONFIG_SPL_TEXT_BASE=0x402F0400，条件为真，执行条件下的代码
#########################################################################*/
ifneq ($(CONFIG_SPL_TEXT_BASE),)
CPPFLAGS += -DCONFIG_SPL_TEXT_BASE=$(CONFIG_SPL_TEXT_BASE)
endif

#########################################################################/*
#CONFIG_SPL_BUILD = y
#判断 CONFIG_SPL_BUILD 是否为 y，而 CONFIG_SPL_BUILD=y，条件为真，执行条件下的代码
#########################################################################*/
ifeq ($(CONFIG_SPL_BUILD),y)
CPPFLAGS += -DCONFIG_SPL_BUILD
endif

#########################################################################/*
#判断 CONFIG_SPL_BUILD 是否为 空，而 RESET_VECTOR_ADDRESS 为空，条件为假，不执行条件下的代码
#########################################################################*/
ifneq ($(RESET_VECTOR_ADDRESS),)
CPPFLAGS += -DRESET_VECTOR_ADDRESS=$(RESET_VECTOR_ADDRESS)
endif

#########################################################################
#当前 	OBJTREE = ./am335x
#		SRCTREE = ./
#判断变量OBJTREE,SRCTREE是否相等,其不相同，则条件为真,执行条件下的代码
#########################################################################
ifneq ($(OBJTREE),$(SRCTREE))
CPPFLAGS += -I$(OBJTREE)/include2 -I$(OBJTREE)/include
endif

CPPFLAGS += -I$(TOPDIR)/include
CPPFLAGS += -fno-builtin -ffreestanding -nostdinc	\
	-isystem $(gccincdir) -pipe $(PLATFORM_CPPFLAGS)

#没有定义BUILD_TAG，因此：CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes
ifdef BUILD_TAG
CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes \
	-DBUILD_TAG='"$(BUILD_TAG)"'
else
CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes
endif

CFLAGS += $(call cc-option,-fno-stack-protector)
# Some toolchains enable security related warning flags by default,
# but they don't make much sense in the u-boot world, so disable them.
CFLAGS += $(call cc-option,-Wno-format-nonliteral)
CFLAGS += $(call cc-option,-Wno-format-security)

# $(CPPFLAGS) sets -g, which causes gcc to pass a suitable -g
# option to the assembler.
AFLAGS_DEBUG :=

# turn jbsr into jsr for m68k
ifeq ($(ARCH),m68k)
ifeq ($(findstring 3.4,$(shell $(CC) --version)),3.4)
AFLAGS_DEBUG := -Wa,-gstabs,-S
endif
endif

AFLAGS := $(AFLAGS_DEBUG) -D__ASSEMBLY__ $(CPPFLAGS)

LDFLAGS += $(PLATFORM_LDFLAGS)
LDFLAGS_FINAL += -Bstatic

LDFLAGS_u-boot += -T $(obj)u-boot.lds $(LDFLAGS_FINAL)
ifneq ($(CONFIG_SYS_TEXT_BASE),)
LDFLAGS_u-boot += -Ttext $(CONFIG_SYS_TEXT_BASE)
endif

LDFLAGS_u-boot-spl += -T $(obj)u-boot-spl.lds $(LDFLAGS_FINAL)
ifneq ($(CONFIG_SPL_TEXT_BASE),)
LDFLAGS_u-boot-spl += -Ttext $(CONFIG_SPL_TEXT_BASE)
endif

# Location of a usable BFD library, where we define "usable" as
# "built for ${HOST}, supports ${TARGET}".  Sensible values are
# - When cross-compiling: the root of the cross-environment
# - Linux/ppc (native): /usr
# - NetBSD/ppc (native): you lose ... (must extract these from the
#   binutils build directory, plus the native and U-Boot include
#   files don't like each other)
#
# So far, this is used only by tools/gdb/Makefile.

ifeq ($(HOSTOS),darwin)
BFD_ROOT_DIR =		/usr/local/tools
else
ifeq ($(HOSTARCH),$(ARCH))
# native
BFD_ROOT_DIR =		/usr
else
#BFD_ROOT_DIR =		/LinuxPPC/CDK		# Linux/i386
#BFD_ROOT_DIR =		/usr/pkg/cross		# NetBSD/i386
BFD_ROOT_DIR =		/opt/powerpc
endif
endif

#########################################################################

export	HOSTCC HOSTCFLAGS HOSTLDFLAGS PEDCFLAGS HOSTSTRIP CROSS_COMPILE \
	AS LD CC CPP AR NM STRIP OBJCOPY OBJDUMP MAKE
export	CONFIG_SYS_TEXT_BASE PLATFORM_CPPFLAGS PLATFORM_RELFLAGS CPPFLAGS CFLAGS AFLAGS

#########################################################################

# Allow boards to use custom optimize flags on a per dir/file basis
BCURDIR = $(subst $(SRCTREE)/,,$(CURDIR:$(obj)%=%))
ALL_AFLAGS = $(AFLAGS) $(AFLAGS_$(BCURDIR)/$(@F)) $(AFLAGS_$(BCURDIR))
ALL_CFLAGS = $(CFLAGS) $(CFLAGS_$(BCURDIR)/$(@F)) $(CFLAGS_$(BCURDIR))
$(obj)%.s:	%.S
	$(CPP) $(ALL_AFLAGS) -o $@ $<
$(obj)%.o:	%.S
	$(CC)  $(ALL_AFLAGS) -o $@ $< -c
$(obj)%.o:	%.c
	$(CC)  $(ALL_CFLAGS) -o $@ $< -c
$(obj)%.i:	%.c
	$(CPP) $(ALL_CFLAGS) -o $@ $< -c
$(obj)%.s:	%.c
	$(CC)  $(ALL_CFLAGS) -o $@ $< -c -S

#########################################################################

# If the list of objects to link is empty, just create an empty built-in.o
cmd_link_o_target = $(if $(strip $1),\
		      $(LD) $(LDFLAGS) -r -o $@ $1,\
		      rm -f $@; $(AR) rcs $@ )

#########################################################################



mkconfig 详解： 


#!/bin/sh -e

# Script to create header files and links to configure
# U-Boot for a specific board.
#
# Parameters:  Target  Architecture  CPU  Board [VENDOR] [SOC]
#
# (C) 2002-2010 DENX Software Engineering, Wolfgang Denk 
#

APPEND=no	# Default: Create new config file
BOARD_NAME=""	# Name to print in make output
TARGETS=""

arch=""
cpu=""
board=""
vendor=""
soc=""
options=""

#########################################################################
#我们执行脚本的命令是mkconfig -A am335x_evm,$#表示的是参数的个数，$1表示的是第一个参数 
#接下来就是使用egrep命令把单板名字$2的那行找出来，如果失败的话说明没有找到相应的单板，退出。
#如果找到的话，我们需要的信息都有了.
#set $(line) 这句话就是将line的信息设置成系统的位置变量   
#line 就是在boards.cfg文件中am335x_evm的那行，而-i表示忽略大小写    
#在boards.cfg文件中，有    
#Target          ARCH        CPU         Board name          Vendor          SoC         Options    
#am335x_evm      arm         armv7       am335x              ti             ti81xx
#  set ${line}    
#  set也可用于在脚本内部给出其运行参数,所以这个时候参数就变为:
#"am335x_evm      arm         armv7       am335x              ti             ti81xx"    
#这个时候参数个数就变成6个了 
#########################################################################
if [ \( $# -eq 2 \) -a \( "$1" = "-A" \) ] ; then
	# Automatic mode
	line=`egrep -i "^[[:space:]]*${2}[[:space:]]" boards.cfg` || {
		echo "make: *** No rule to make target \`$2_config'.  Stop." >&2
		exit 1
	}

	set ${line}
	# add default board name if needed
	[ $# = 3 ] && set ${line} ${1}
fi

#########################################################################
#环境变量$#表示传递给脚本的参数个数，这里的命令有6个参数，因此$#是6 。
#shift的作用是使$1=$2，$2=$3，$3=$4….，而原来的$1将丢失。因此while循环的作用是，
#依次处理传递给mkconfig脚本的选项。由于我们并没有传递给mkconfig任何的选项，
#因此while循环中的代码不起作用。
#########################################################################
#参数个数大于 0 
while [ $# -gt 0 ] ; do 	
	case "$1" in
	--) shift ; break ;;
	-a) shift ; APPEND=yes ;;
	-n) shift ; BOARD_NAME="${1%_config}" ; shift ;;
	-t) shift ; TARGETS="`echo $1 | sed 's:_: :g'` ${TARGETS}" ; shift ;;
	*)  break ;;
	esac
done

#参数个数少于 4 ,异常退出
[ $# -lt 4 ] && exit 1
#参数个数大于 7 ,异常退出
[ $# -gt 7 ] && exit 1

#########################################################################
#${1%_config}的意思 $1 如果以 _config 后缀结束的话，则要去掉 _config 后缀。
#$1 (当前为 am335x_evm），则 CONFIG_NAME = am335x_evm；
#假设 $1 为 am335x_evm_config，则 CONFIG_NAME = am335x_evm。
#########################################################################
# Strip all options and/or _config suffixes
CONFIG_NAME="${1%_config}"

#如果  BOARD_NAME 为空，则把 $1 参数赋值给 BOARD_NAME
#（如果以 _config 后缀结束的话，则要去掉 _config 后缀）。
#当前 BOARD_NAME = am335x_evm
[ "${BOARD_NAME}" ] || BOARD_NAME="${1%_config}"

#arch=arm
arch="$2"

#cpu=armv7
cpu="$3"

#board=am335x
if [ "$4" = "-" ] ; then
	board=${BOARD_NAME}
else
	board="$4"
fi

#参数个数大于 4，且 参数5 并不为 “-”，则 vendor = ti
[ $# -gt 4 ] && [ "$5" != "-" ] && vendor="$5"

#参数个数大于 5，且 参数6 并不为 “-”，则 soc = ti81xx
[ $# -gt 5 ] && [ "$6" != "-" ] && soc="$6"

#当前参数只有 6 个，条件为假,这一段代码不会被执行
[ $# -gt 6 ] && [ "$7" != "-" ] && {
	# check if we have a board config name in the options field
	# the options field mave have a board config name and a list
	# of options, both separated by a colon (':'); the options are
	# separated by commas (',').
	#
	# Check for board name
	tmp="${7%:*}"
	if [ "$tmp" ] ; then
		CONFIG_NAME="$tmp"
	fi
	# Check if we only have a colon...
	if [ "${tmp}" != "$7" ] ; then
		options=${7#*:}
		TARGETS="`echo ${options} | sed 's:,: :g'` ${TARGETS}"
	fi
}

#########################################################################
#ARCH是在顶层makefile中定义的，在此刻还是为空的。    
#如果ARCH已经有值了，那么就检测ARCH和arch是否匹配了. 
#########################################################################
if [ "${ARCH}" -a "${ARCH}" != "${arch}" ]; then
	echo "Failed: \$ARCH=${ARCH}, should be '${arch}' for ${BOARD_NAME}" 1>&2
	exit 1
fi

#########################################################################
#判断 options 是否为空，当前 options 为空，BOARD_NAME 为 am335x_evm,
#因此显示如下：Configuring for am335x_evm board...
#########################################################################
if [ "$options" ] ; then
	echo "Configuring for ${BOARD_NAME} - Board: ${CONFIG_NAME}, Options: ${options}"
else
	echo "Configuring for ${BOARD_NAME} board..."
fi

#########################################################################
#SRCTREE 为uboot根目录，设为 ： ./ （即当前目录，即uboot根目录）
#则 OBJTREE 为 SRCTREE目录下的am335x 目录，即为：./am335x/
#########################################################################
#
# Create link to architecture specific headers
#
if [ "$SRCTREE" != "$OBJTREE" ] ; then
	#创建include目录：./am335x/include/
	# -p 表示如果目录已存在，并不会产生错误
	mkdir -p ${OBJTREE}/include

	#创建include2目录：./am335x/include2/
	mkdir -p ${OBJTREE}/include2

	#进入到 ./am335x/include2/ 目录中
	cd ${OBJTREE}/include2

	#如果 ./am335x/include2 目录中有 asm 文件的话，则删除。
	# -f 表示如果文件不存在，不提示 
	rm -f asm

	#创建符号链接asm，其指向 ./arch/arm/include/asm
	ln -s ${SRCTREE}/arch/${arch}/include/asm asm

	#创建变量 LNPREFIX ，其赋值为 ：./arch/arm/include/asm
	LNPREFIX=${SRCTREE}/arch/${arch}/include/asm/

	#进入到 ./am335x/include/ 目录中
	cd ../include

	#创建 asm目录：./am335x/include/asm/
	mkdir -p asm
else
	cd ./include
	rm -f asm
	ln -s ../arch/${arch}/include/asm asm
fi

#当前路径为：./am335x/include/。
#删除 asm/arch 文件
rm -f asm/arch

#########################################################################
#判断 soc 是否为空，当前 soc = ti81xx，并不为空。
#因此创建符号链接 asm/arch，即 ./am335x/include/asm/arch 指向 ./arch/arm/include/asm/arch-ti81xx/ 目录
#########################################################################
if [ -z "${soc}" ] ; then
	ln -s ${LNPREFIX}arch-${cpu} asm/arch
else
	ln -s ${LNPREFIX}arch-${soc} asm/arch
fi

#########################################################################
#判断 变量 arch 是否为 arm，当前的arch为 arm，条件为真。
#当前路径为：./am335x/include/。
#删除 asm/proc 文件
#创建符号链接 asm/proc，即 ./am335x/include/asm/proc 指向 ./arch/arm/include/asm/proc-armv/ 目录.
#########################################################################
if [ "${arch}" = "arm" ] ; then
	rm -f asm/proc
	ln -s ${LNPREFIX}proc-armv asm/proc
fi

#########################################################################
#当前路径为：./am335x/include/。
#	> 表示如果文件不存在，则创建文件；如果文件存在，则清空文件
# 	>>表示添加到文件的末尾
#########################################################################
#
# Create include file for Make
#
echo "ARCH   = ${arch}"  >  config.mk
echo "CPU    = ${cpu}"   >> config.mk
echo "BOARD  = ${board}" >> config.mk

#如果变量 vendor 不为空，则输入到文件末尾
[ "${vendor}" ] && echo "VENDOR = ${vendor}" >> config.mk

#如果变量 soc 不为空，则输入到文件末尾
[ "${soc}"    ] && echo "SOC    = ${soc}"    >> config.mk
#########################################################################
#最后得到文件 ./am335x/include/config.mk 内容如下：
#	ARCH   = arm
#	CPU    = armv7
#	BOARD  = am335x
#	VENDOR = ti
#	SOC    = ti81xx
#########################################################################

#判断 变量vendor 是否为空，当前变量vendor 为 ti，则条件为假，其中 board 为 am335x
#则 BOARDDIR = ti/am335x
# Assign board directory to BOARDIR variable
if [ -z "${vendor}" ] ; then
    BOARDDIR=${board}
else
    BOARDDIR=${vendor}/${board}
fi

#########################################################################
#判断 变量APPEND 是否为 yes，当前 APPEND为no，条件为假。
#则创建config.h 文件，如果该文件已存在，则清空。
#########################################################################
#
# Create board specific header file
#
if [ "$APPEND" = "yes" ]	# Append to existing config file
then
	echo >> config.h
else
	> config.h		# Create new config file
fi
echo "/* Automatically generated - do not edit */" >>config.h

#当前 变量TARGETS 为空，其下面代码不会被执行
for i in ${TARGETS} ; do
	i="`echo ${i} | sed '/=/ {s/=/	/;q; } ; { s/$/	1/; }'`"
	echo "#define CONFIG_${i}" >>config.h ;
done

#将输入的内容追加到config.h中，直到出现“EOF”这样的标识为止。
cat << EOF >> config.h
#define CONFIG_BOARDDIR board/$BOARDDIR
#include 
#include 
#include 
#include 
EOF
#########################################################################
#最后得到文件 ./am335x/include/config.h 内容如下：
#	/* Automatically generated - do not edit */
#	#define CONFIG_BOARDDIR board/ti/am335x
#	#include 
#	#include 
#	#include 
#	#include 
#########################################################################


#正常退出
exit 0

阅读(2512) | 评论(0) | 转发(0) |
0

上一篇：V4L2之usb camera

下一篇：如何在Linux平台下开发实际的音频应用程序

给主人留下些什么吧！~~
关于我们 | 关于IT168 | 联系方式 | 广告合作 | 法律声明 | 免费注册

Copyright 2001-2010 ChinaUnix.net All Rights Reserved 北京皓辰网域网络信息技术有限公司. 版权所有

感谢所有关心和支持过ChinaUnix的朋友们

16024965号-6