Beaglebone Black——嵌入式linux系统u-boot编译

          首先是U-boot源码的来源，由于使用的是TI的BBB板子，所以TI自然也提供了自己定制的u-boot源码，该源码就在TI-SDK包中有，另外该安装包中的u-boot版本是2013.10版本，内核版本为3.12.10，除了源码包还自带工具链。

TI-SDK最新版下载链接：http://software-dl.ti.com/sitara_linux/esd/AM335xSDK/latest/index_FDS.html

          当然，还有另外一个德国佬官方的u-boot源码，网站首页：http://www.denx.de/en/News/WebHome和git代码库：git://www.denx.de/git/u-boot.git。

          以官方u-boot为例进行u-boot的编译，进入源码根目录可以看到内容如下，

zhouyu@zhouyu-virtual-machine:~$ cd u-boot/zhouyu@zhouyu-virtual-machine:~/u-boot$ lsapi        configs  dts       Kconfig      Makefile  snapshot.commitarch       CREDITS  examples  lib          net       splboard      disk     fs        Licenses     post      testcommon     doc      include   MAINTAINERS  README    toolsconfig.mk  drivers  Kbuild    MAKEALL      scripts

其中打开根目录下的Makefile文件，可以查看到本源码的版本，如下图：

step1:在进行任何操作之前，先清除源码树，

zhouyu@zhouyu-virtual-machine:~/u-boot$ make distclean  CLEAN   scripts/basic  CLEAN   scripts/kconfig  CLEAN   include/config include/generated spl  CLEAN   .config include/autoconf.mk include/autoconf.mk.dep include/config.hzhouyu@zhouyu-virtual-machine:~/u-boot$ 

step2：编译之前的配置工作

zhouyu@zhouyu-virtual-machine:~/u-boot$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 O=am335x_beaglebone_black am335x_boneblack_defconfig  GEN     /home/zhouyu/u-boot/am335x_beaglebone_black/Makefile  HOSTCC  scripts/basic/fixdep  HOSTCC  scripts/kconfig/conf.o  SHIPPED scripts/kconfig/zconf.tab.c  SHIPPED scripts/kconfig/zconf.lex.c  SHIPPED scripts/kconfig/zconf.hash.c  HOSTCC  scripts/kconfig/zconf.tab.o  HOSTLD  scripts/kconfig/conf## configuration written to .config### configuration written to spl/.config#zhouyu@zhouyu-virtual-machine:~/u-boot$ 

          make之后的第一个参数向Makefile指明了编译的目标体系结构，第二个参数向Makefile指明了使用哪个编译工具链，第四个参数告诉make程序，这个编译任务要分配4个线程来并行进行，以加快编译速度，通常这个数依据自己的处理器的核数来选择，一般选择2倍核数，第五个参数告诉Makefile编译时产生的中间文件以及最后的结果都存放在源码树根目录下的am335x_beaglebone_black文件夹中，这对于使用同一个源码树来编译多个不同配置的u-boot时是一个很好的选择。最后一个参数向Makefile指明了要使用哪个文件来进行具体的配置，最后所有的配置都将写进源码树根目录下面的.config文件中。

          而至于具体后面应该跟一个什么样的配置参数，可以从下图中寻找答案

         在源码树的configs文件夹中可以看到很多配置文件，我选择的是第一个红线框的配置文件。

 

step3：正式开始编译工作

zhouyu@zhouyu-virtual-machine:~/u-boot$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j4 O=am335x_beaglebone_black all  GEN     /home/zhouyu/u-boot/am335x_beaglebone_black/Makefilescripts/kconfig/conf --silentoldconfig Kconfigscripts/kconfig/conf --silentoldconfig Kconfig  CHK     include/config.h  UPD     include/config.h  GEN     include/autoconf.mk  GEN     include/autoconf.mk.dep  GEN     spl/include/autoconf.mk  CHK     include/config/uboot.release  CHK     include/generated/timestamp_autogenerated.h  GEN     /home/zhouyu/u-boot/am335x_beaglebone_black/Makefile  UPD     include/generated/timestamp_autogenerated.h  UPD     include/config/uboot.release  Using /home/zhouyu/u-boot as source for U-Boot  CHK     include/generated/version_autogenerated.h  UPD     include/generated/version_autogenerated.h  CC      lib/asm-offsets.s  CC      arch/arm/lib/asm-offsets.s  GEN     include/generated/asm-offsets.h  GEN     include/generated/generic-asm-offsets.h  LDS     u-boot.lds  HOSTCC  tools/gen_eth_addr  HOSTCC  tools/img2srec  HOSTCC  tools/aisimage.o  HOSTCC  tools/atmelimage.o  WRAP    tools/common/bootm.c  WRAP    tools/common/image-fit.c  WRAP    tools/common/image.c  HOSTCC  tools/default_image.o  HOSTCC  tools/dumpimage.o  HOSTCC  tools/fit_common.o  HOSTCC  tools/fit_image.o  HOSTCC  tools/gpimage-common.o  HOSTCC  tools/gpimage.o  HOSTCC  tools/image-host.o  HOSTCC  tools/imagetool.o  HOSTCC  tools/imximage.o  HOSTCC  tools/kwbimage.o  WRAP    tools/lib/crc32.c  WRAP    tools/lib/fdtdec.c  WRAP    tools/lib/fdtdec_common.c  WRAP    tools/lib/libfdt/fdt.c  WRAP    tools/lib/libfdt/fdt_ro.c  WRAP    tools/lib/libfdt/fdt_rw.c  WRAP    tools/lib/libfdt/fdt_strerror.c  WRAP    tools/lib/libfdt/fdt_wip.c  WRAP    tools/lib/md5.c  WRAP    tools/lib/sha1.c  WRAP    tools/lib/sha256.c  HOSTCC  tools/mkenvimage.o  HOSTCC  tools/mkimage.o  HOSTCC  tools/mxsimage.o  HOSTCC  tools/omapimage.o  HOSTCC  tools/os_support.o  HOSTCC  tools/pbl_crc32.o  HOSTCC  tools/pblimage.o  HOSTCC  tools/ublimage.o  HOSTCC  tools/proftool  HOSTCC  tools/common/bootm.o  HOSTCC  tools/common/image-fit.o  HOSTCC  tools/common/image.o  HOSTCC  tools/lib/crc32.o  HOSTCC  tools/lib/fdtdec.o  HOSTCC  tools/lib/fdtdec_common.o  HOSTCC  tools/lib/libfdt/fdt.o  HOSTCC  tools/lib/libfdt/fdt_ro.o  HOSTCC  tools/lib/libfdt/fdt_rw.o  HOSTCC  tools/lib/libfdt/fdt_strerror.o  HOSTCC  tools/lib/libfdt/fdt_wip.o  HOSTCC  tools/lib/md5.o  HOSTCC  tools/lib/sha1.o  HOSTCC  tools/lib/sha256.o  HOSTLD  tools/mkenvimage  HOSTLD  tools/dumpimage  HOSTLD  tools/mkimage  LD      arch/arm/cpu/built-in.o  CC      arch/arm/cpu/armv7/cache_v7.o  CC      arch/arm/cpu/armv7/am33xx/clock_am33xx.o  CC      arch/arm/cpu/armv7/am33xx/clock.o  AS      arch/arm/lib/vectors.o  AS      arch/arm/lib/crt0.o  AS      arch/arm/lib/relocate.o  CC      arch/arm/lib/bootm-fdt.o  CC      arch/arm/lib/bootm.o  CC      arch/arm/cpu/armv7/am33xx/sys_info.o  CC      arch/arm/cpu/armv7/cpu.o  CC      arch/arm/cpu/armv7/am33xx/ddr.o  CC      arch/arm/cpu/armv7/syslib.o  CC      arch/arm/lib/sections.o  CC      arch/arm/lib/interrupts.o  CC      board/ti/am335x/board.o  CC      arch/arm/cpu/armv7/am33xx/emif4.o  CC      arch/arm/cpu/armv7/omap-common/reset.o  CC      arch/arm/cpu/armv7/omap-common/timer.o  CC      arch/arm/cpu/armv7/am33xx/board.o  CC      arch/arm/lib/reset.o  LD      board/ti/am335x/built-in.o  CC      arch/arm/cpu/armv7/omap-common/utils.o  CC      arch/arm/lib/cache.o  CC      arch/arm/cpu/armv7/am33xx/mux.o  CC      arch/arm/lib/cache-cp15.o  CC      arch/arm/cpu/armv7/omap-common/omap-cache.o  LD      arch/arm/cpu/armv7/am33xx/built-in.o  CC      common/main.o  CC      disk/part.o  AR      arch/arm/lib/lib.a  CC      arch/arm/cpu/armv7/omap-common/boot-common.o  CC      arch/arm/lib/eabi_compat.o  CC      common/command.o  LD      arch/arm/lib/built-in.o  AS      arch/arm/cpu/armv7/omap-common/lowlevel_init.o  CC      arch/arm/cpu/armv7/omap-common/mem-common.o  LD      drivers/block/built-in.o  CC      disk/part_dos.o  CC      drivers/bootcount/bootcount.o  LD      arch/arm/cpu/armv7/omap-common/built-in.o  AS      arch/arm/cpu/armv7/start.o  LD      arch/arm/cpu/armv7/built-in.o  CC      drivers/bootcount/bootcount_davinci.o  CC      common/exports.o  LD      drivers/dma/built-in.o  CC      common/hash.o  CC      disk/part_efi.o  LD      drivers/bootcount/built-in.o  LD      drivers/crypto/built-in.o  CC      drivers/gpio/omap_gpio.o  CC      drivers/dfu/dfu.o  CC      common/cli_hush.o  LD      drivers/gpio/built-in.o  CC      drivers/i2c/i2c_core.o  CC      drivers/i2c/omap24xx_i2c.o  CC      drivers/dfu/dfu_mmc.o  LD      disk/built-in.o  LD      drivers/hwmon/built-in.o  LD      drivers/memory/built-in.o  LD      drivers/misc/built-in.o  CC      drivers/pcmcia/tqm8xx_pcmcia.o  CC      drivers/dfu/dfu_ram.o  LD      drivers/i2c/built-in.o  CC      drivers/rtc/date.o  CC      common/cli_simple.o  LD      drivers/pcmcia/built-in.o  CC      common/cli.o  LD      drivers/dfu/built-in.o  CC      common/cli_readline.o  LD      drivers/rtc/built-in.o  LD      drivers/sound/built-in.o  LD      drivers/tpm/built-in.o  LD      drivers/twserial/built-in.o  LD      drivers/video/built-in.o  CC      drivers/watchdog/omap_wdt.o  CC      common/s_record.o  CC      common/xyzModem.o  CC      common/cmd_disk.o  CC      common/autoboot.o  LD      drivers/watchdog/built-in.o  LD      drivers/built-in.o  CC      common/board_f.o  CC      common/board_r.o  CC      drivers/input/input.o  CC      common/cmd_boot.o  CC      common/cmd_bootm.o  CC      common/bootm.o  LD      drivers/input/built-in.o  LD      drivers/mtd/built-in.o  CC      drivers/mmc/mmc.o  CC      common/bootm_os.o  CC      drivers/mmc/omap_hsmmc.o  CC      common/cmd_help.o  CC      common/cmd_version.o  CC      common/env_attr.o  CC      common/env_callback.o  CC      common/env_flags.o  CC      common/env_mmc.o  CC      common/cmd_source.o  CC      drivers/mmc/mmc_write.o  CC      common/cmd_bdinfo.o  CC      common/cmd_console.o  LD      drivers/mtd/onenand/built-in.o  CC      common/cmd_echo.o  LD      drivers/mmc/built-in.o  CC      drivers/mtd/spi/sf.o  CC      drivers/net/cpsw.o  CC      common/cmd_eeprom.o  CC      drivers/mtd/spi/sf_params.o  CC      drivers/net/phy/phy.o  CC      drivers/mtd/spi/sf_probe.o  CC      common/cmd_exit.o  CC      drivers/net/phy/smsc.o  LD      drivers/net/built-in.o  LD      drivers/pci/built-in.o  CC      common/cmd_ext4.o  CC      drivers/mtd/spi/sf_ops.o  LD      drivers/power/built-in.o  LD      drivers/power/battery/built-in.o  LD      drivers/power/fuel_gauge/built-in.o  LD      drivers/net/phy/built-in.o  LD      drivers/power/mfd/built-in.o  CC      common/cmd_ext2.o  CC      drivers/serial/serial.o  CC      drivers/power/pmic/pmic_tps65217.o  CC      common/cmd_fat.o  LD      drivers/mtd/spi/built-in.o  CC      drivers/spi/spi.o  CC      drivers/power/pmic/pmic_tps65910.o  CC      common/cmd_fdt.o  CC      drivers/serial/ns16550.o  CC      drivers/spi/omap3_spi.o  LD      drivers/power/pmic/built-in.o  LD      drivers/usb/eth/built-in.o  CC      common/fdt_support.o  CC      drivers/serial/serial_ns16550.o  LD      drivers/serial/built-in.o  CC      drivers/usb/gadget/epautoconf.o  CC      common/cmd_fs.o  LD      drivers/spi/built-in.o  CC      common/cmd_gpio.o  CC      drivers/usb/gadget/config.o  CC      common/cmd_i2c.o  CC      common/cmd_itest.o  CC      drivers/usb/gadget/usbstring.o  LD      drivers/usb/host/built-in.o  CC      common/cmd_load.o  CC      drivers/usb/gadget/g_dnl.o  CC      common/cmd_mem.o  LD      drivers/usb/musb/built-in.o  LD      drivers/usb/phy/built-in.o  CC      drivers/usb/musb-new/musb_gadget.o  LD      drivers/usb/ulpi/built-in.o  CC      fs/fs.o  CC      common/miiphyutil.o  CC      fs/ext4/ext4fs.o  CC      drivers/usb/gadget/f_dfu.o  CC      fs/ext4/ext4_common.o  CC      drivers/usb/gadget/ether.o  CC      drivers/usb/musb-new/musb_gadget_ep0.o  CC      common/cmd_mii.o  CC      drivers/usb/musb-new/musb_core.o  CC      common/cmd_mdio.o  CC      fs/ext4/dev.o  CC      common/cmd_misc.o  CC      drivers/usb/gadget/rndis.o  LD      fs/ext4/built-in.o  CC      fs/fat/fat_write.o  CC      drivers/usb/musb-new/musb_uboot.o  CC      common/cmd_mmc.o  CC      drivers/usb/musb-new/musb_host.o  LD      drivers/usb/gadget/built-in.o  CC      common/cmd_net.o  CC      lib/lzo/lzo1x_decompress.o  CC      common/cmd_part.o  CC      common/cmd_pcmcia.o  LD      lib/lzo/built-in.o  CC      lib/zlib/zlib.o  CC      common/cmd_sf.o  CC      drivers/usb/musb-new/musb_dsps.o  LD      drivers/usb/musb-new/built-in.o  CC      common/cmd_spi.o  CC      common/cmd_test.o  CC      fs/fat/file.o  CC      lib/crc7.o  CC      common/cmd_usb.o  CC      common/usb.o  LD      fs/fat/built-in.o  LD      fs/built-in.o  LD      lib/zlib/built-in.o  CC      lib/crc8.o  CC      lib/libfdt/fdt.o  CC      lib/crc16.o  CC      lib/fdtdec_common.o  CC      lib/libfdt/fdt_ro.o  CC      common/usb_hub.o  CC      lib/gunzip.o  CC      common/usb_storage.o  CC      lib/initcall.o  CC      common/cmd_ximg.o  CC      lib/lmb.o  CC      lib/libfdt/fdt_rw.o  CC      common/cmd_spl.o  CC      lib/ldiv.o  CC      lib/md5.o  CC      net/arp.o  CC      common/flash.o  CC      lib/libfdt/fdt_strerror.o  CC      lib/libfdt/fdt_sw.o  CC      common/splash.o  CC      net/bootp.o  CC      lib/net_utils.o  CC      common/cmd_dfu.o  CC      lib/libfdt/fdt_wip.o  CC      lib/qsort.o  CC      net/eth.o  CC      common/cmd_gpt.o  CC      lib/sha1.o  CC      lib/libfdt/fdt_empty_tree.o  CC      lib/libfdt/fdt_addresses.o  LD      lib/libfdt/built-in.o  CC      lib/sha256.o  CC      net/net.o  CC      common/cmd_nvedit.o  CC      lib/strmhz.o  CC      lib/hashtable.o  CC      common/env_common.o  CC      net/nfs.o  CC      net/ping.o  CC      common/console.o  CC      lib/errno.o  CC      lib/display_options.o  CC      net/tftp.o  CC      lib/ctype.o  CC      lib/crc32.o  CC      lib/div64.o  CC      common/dlmalloc.o  LD      net/built-in.o  CC      lib/hang.o  LD      test/built-in.o  CC      lib/linux_string.o  LD      test/dm/built-in.o  CC      lib/string.o  CC      common/image.o  CC      common/image-fdt.o  CC      lib/time.o  AS      spl/arch/arm/lib/vectors.o  AS      spl/arch/arm/lib/crt0.o  CC      spl/arch/arm/lib/spl.o  CC      common/image-fit.o  CC      spl/arch/arm/lib/sections.o  CC      lib/uuid.o  CC      spl/arch/arm/lib/interrupts.o  CC      common/memsize.o  CC      spl/arch/arm/lib/reset.o  CC      lib/vsprintf.o  CC      common/stdio.o  CC      spl/arch/arm/lib/cache.o  CC      spl/arch/arm/lib/cache-cp15.o  AR      spl/arch/arm/lib/lib.a  CC      spl/arch/arm/lib/eabi_compat.o  LD      spl/arch/arm/lib/built-in.o  CC      spl/arch/arm/cpu/armv7/cache_v7.o  CC      spl/arch/arm/cpu/armv7/am33xx/clock_am33xx.o  LD      common/built-in.o  CC      spl/arch/arm/cpu/armv7/am33xx/clock.o  CC      spl/arch/arm/cpu/armv7/cpu.o  CC      spl/arch/arm/cpu/armv7/syslib.o  LD      lib/built-in.o  AS      spl/arch/arm/cpu/armv7/lowlevel_init.o  AS      spl/arch/arm/cpu/armv7/start.o  CC      spl/arch/arm/cpu/armv7/am33xx/sys_info.o  CC      spl/arch/arm/cpu/armv7/omap-common/reset.o  CC      spl/arch/arm/cpu/armv7/am33xx/ddr.o  CC      examples/standalone/stubs.o  CC      spl/arch/arm/cpu/armv7/omap-common/timer.o  CC      spl/arch/arm/cpu/armv7/am33xx/emif4.o  CC      spl/arch/arm/cpu/armv7/omap-common/utils.o  CC      examples/standalone/hello_world.o  CC      spl/board/ti/am335x/mux.o  CC      spl/arch/arm/cpu/armv7/am33xx/board.o  CC      spl/arch/arm/cpu/armv7/omap-common/omap-cache.o  CC      spl/arch/arm/cpu/armv7/am33xx/mux.o  LD      examples/standalone/libstubs.o  CC      spl/board/ti/am335x/board.o  LD      examples/standalone/hello_world  CC      spl/arch/arm/cpu/armv7/omap-common/boot-common.o  LD      spl/arch/arm/cpu/armv7/am33xx/built-in.o  AS      spl/arch/arm/cpu/armv7/omap-common/lowlevel_init.o  CC      spl/arch/arm/cpu/armv7/omap-common/mem-common.o  OBJCOPY examples/standalone/hello_world.srec  LD      spl/board/ti/am335x/built-in.o  CC      spl/common/spl/spl.o  OBJCOPY examples/standalone/hello_world.bin  LD      spl/arch/arm/cpu/armv7/omap-common/built-in.o  CC      spl/common/spl/spl_ymodem.o  LD      spl/arch/arm/cpu/armv7/built-in.o  CC      spl/common/spl/spl_net.o  CC      spl/common/spl/spl_mmc.o  CC      spl/common/spl/spl_fat.o  CC      spl/disk/part.o  CC      spl/disk/part_dos.o  CC      spl/common/xyzModem.o  LD      spl/common/spl/built-in.o  CC      spl/drivers/i2c/i2c_core.o  CC      spl/common/miiphyutil.o  CC      spl/drivers/i2c/omap24xx_i2c.o  CC      spl/disk/part_efi.o  CC      spl/common/env_attr.o  CC      spl/common/env_flags.o  CC      spl/common/env_callback.o  LD      spl/drivers/i2c/built-in.o  CC      spl/drivers/gpio/omap_gpio.o  CC      spl/common/env_nowhere.o  CC      spl/common/cmd_nvedit.o  LD      spl/disk/built-in.o  CC      spl/drivers/mmc/mmc.o  LD      spl/drivers/gpio/built-in.o  CC      spl/drivers/mmc/omap_hsmmc.o  CC      spl/common/env_common.o  CC      spl/drivers/serial/serial.o  CC      spl/drivers/serial/ns16550.o  CC      spl/common/console.o  CC      spl/drivers/serial/serial_ns16550.o  LD      spl/drivers/mmc/built-in.o  CC      spl/fs/fat/fat_write.o  CC      spl/lib/crc16.o  LD      spl/drivers/serial/built-in.o  CC      spl/lib/net_utils.o  CC      spl/lib/hashtable.o  LD      spl/drivers/power/built-in.o  CC      spl/common/dlmalloc.o  CC      spl/lib/errno.o  CC      spl/lib/display_options.o  CC      spl/common/image.o  CC      spl/lib/crc32.o  CC      spl/common/image-fdt.o  CC      spl/lib/ctype.o  CC      spl/lib/div64.o  CC      spl/lib/hang.o  CC      spl/common/memsize.o  CC      spl/common/stdio.o  CC      spl/lib/linux_string.o  CC      spl/lib/string.o  LD      u-boot  LD      spl/common/built-in.o  CC      spl/drivers/power/pmic/pmic_tps65217.o  LD      spl/fs/fat/built-in.o  LD      spl/fs/built-in.o  CC      spl/drivers/power/pmic/pmic_tps65910.o  CC      spl/lib/time.o  LD      spl/drivers/power/pmic/built-in.o  CC      spl/net/arp.o  CC      spl/net/bootp.o  CC      spl/lib/uuid.o  CC      spl/net/eth.o  CC      spl/drivers/watchdog/omap_wdt.o  CC      spl/lib/vsprintf.o  LD      spl/drivers/watchdog/built-in.o  CC      spl/drivers/usb/musb-new/musb_gadget.o  LD      spl/arch/arm/cpu/built-in.o  CC      spl/drivers/usb/musb-new/musb_gadget_ep0.o  CC      spl/net/net.o  LD      spl/lib/built-in.o  LDS     spl/u-boot-spl.lds  CC      spl/drivers/usb/musb-new/musb_core.o  CC      spl/drivers/usb/musb-new/musb_uboot.o  CC      spl/net/tftp.o  CC      spl/drivers/usb/musb-new/musb_host.o  CC      spl/drivers/usb/musb-new/musb_dsps.o  LD      spl/net/built-in.o  OBJCOPY u-boot.bin  OBJCOPY u-boot.srec  LD      spl/drivers/usb/musb-new/built-in.o  LD      spl/u-boot-spl  OBJCOPY spl/u-boot-spl.bin  MKIMAGE MLO  MKIMAGE u-boot.img

 

编译工作至此完成。得到的结果如下图

图中所示文件和文件夹都在O=am335x_beaglebone_black所指定的文件夹中。

u-boot——ELF格式的可执行文件，由于里面含有调试程序所选的信息，所以该格式的可执行文件体积最大。

u-boot.bin——可以直接写入Flash的二进制可执行文件，直接被运行。

u-boot.srec——u-boot映像的S-Record格式

u-boot.map——这个文件包含了u-boot可执行文件的映像符号表

MLO——这个文件也是一个引导加载程序，用于加载u-boot.img到SDRAM。

 

u-boot-spl.bin——这个文件实际上就是纯粹的SPL程序，和上图的MLO文件相比，MLO=头部信息+u-boot-spl.bin。

具体使用那个文件根据自己的需要选择。

从SD卡启动时，应该把MLO、u-boot.img文件放到boot分区。

从串口启动时，应该传送u-boot-spl.bin、u-boot.img文件。