U-Boot bootcmd (自动与手动)

Question

我遇到了一个问题，当我打开我的设备时，它挂起在

Starting kernel ...

或者它循环为

Starting kernel ...

resetting ...

但是，如果我中断引导过程并手动运行引导，即：

=> run bootcmd
or
=> boot

然后内核加载正常。

根据DENX (5.9.6.5)，这等同于Uboot应该自动执行的操作。

有人知道让uboot自己运行和手动中断并运行boot有什么区别吗？否则，我该如何开始调试呢？

环境

=> printenv
autoload=no
baudrate=115200
board_name=EVK
board_rev=pilot
boot_fdt=try
bootcmd=echo Booting from network ...; usb start; setenv ethact asx0; if dhcp && tftp $loadaddr $bootfile && tftp $f
dt_addr $fdt_file; then run nfsboot; else echo WARN: Issue with TFTP.; run sdboot; fi;
bootdelay=3
bootfile=zImage
bootscript=echo Running bootscript from mmc ...; source
console=ttymxc1
ethact=asx0
ethprime=FEC
fdt_addr=0x83000000
fdt_file=imx6ul-pilot-v1-evk.dtb
fdt_high=0xffffffff
image=zImage
initrd_high=0xffffffff
ip_dyn=yes
loadaddr=0x80800000
loadbootscript=fatload mmc ${mmcdev}:${mmcpart} ${loadaddr} ${script};
loadfdt=fatload mmc ${mmcdev}:${mmcpart} ${fdt_addr} ${fdt_file}
loadimage=fatload mmc ${mmcdev}:${mmcpart} ${loadaddr} ${image}
mmcargs=setenv bootargs console=${console},${baudrate} root=${mmcroot}
mmcautodetect=yes
mmcboot=echo Booting from mmc ...; run mmcargs; if test ${boot_fdt} = yes || test ${boot_fdt} = try; then if run loadfdt; then bootz ${loadaddr} - ${fdt_addr}; else if test ${boot_fdt} = try; then bootz; else echo WARN: Cannot load the DT; fi; fi; else bootz; fi;
mmcdev=1
mmcpart=1
mmcroot=/dev/mmcblk1p2 rootwait rw
netargs=setenv bootargs console=${console},${baudrate} root=/dev/nfs ip=dhcp nfsroot=${serverip}:${nfsroot},v3,tcp
nfsboot=run netargs; bootz $loadaddr - $fdt_addr
nfsroot=/nfs/rootfs
script=boot.scr
sdboot=echo Booting from mmc ...; mmc dev ${mmcdev}; mmc dev ${mmcdev}; if mmc rescan; then if run loadbootscript; then run bootscript; else if run loadimage; then run mmcboot; else echo ERROR: Cannot run loadimage; fi; fi; else run ERROR: Cannot run mmc rescan; fi;
serverip=192.168.0.219

Environment size: 1714/8188 bytes

Answer 1

此问题与SDBOOT环境变量有关：

sdboot = echo Booting from mmc ...; mmc dev ${mmcdev}; mmc dev ${mmcdev}; 
         if mmc rescan; then 
             if run loadbootscript; then 
                 run bootscript; 
             else 
                 if run loadimage; then 
                     run mmcboot; 
                 else 
                     echo ERROR: Cannot run loadimage; 
                 fi; 
             fi; 
         else 
             echo ERROR: Cannot run mmc rescan; 
         fi;

加载引导脚本失败，出现"** Unable to read file boot.scr **“。我仍然不确定是什么导致了差异，但删除loadbootscript分支并直接转到loadimage解决了这个问题。