2010-04-12 05:58:18     u-boot environment variables

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2010-04-12 05:58:18     u-boot environment variables

Filip Vanalme (BELGIUM)

Message: 88320   

 

Is there a way to pass custom u-boot environment variables to the kernel ? E.g. in u-boot, I do "setenv myVar 1" and "saveenv".

In the Kernel configuration, in "Default bootloader kernel arguments" I tried by adding "test=$(myVar)" or "test=${myVar}" but that doesn't seem to work.

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2010-04-12 08:26:19     Re: u-boot environment variables

Mike Frysinger (UNITED STATES)

Message: 88328   

 

the kernel config controls arguments compiled into the kernel and thus ignores anything from u-boot.  dont do that.

 

look at the default env of u-boot on all ADI boards.  variables are passed on the fly to the kernel command line with all of them.

 

bfin> print bootcmd

bootcmd=run ramboot

bfin> print ramboot

ramboot=tftp $(loadaddr) $(ramfile);run ramargs;run addip;bootm

bfin> print ramargs

ramargs=set bootargs root=/dev/mtdblock0 rw clkin_hz=25000000 earlyprintk=serial,uart0,57600 console=ttyBF0,57600

bfin> print addip

addip=set bootargs $(bootargs) ip=$(ipaddr):$(serverip):$(gatewayip):$(netmask):$(hostname):eth0:off

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2010-04-12 09:39:37     Re: u-boot environment variables

Filip Vanalme (BELGIUM)

Message: 88332   

 

Thanks Mike.

 

I removed it from the Kernel's configuration and looked for it in the U-boot. I found a define CONFIG_EXTRA_ENV_SETTINGS that obviously is intended to add custom environment settings. But how can I retrieve this from the kernel ? Or do I have to add it to an other environment setting e.g. bootargs ?

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2010-04-12 09:43:02     Re: u-boot environment variables

Mike Frysinger (UNITED STATES)

Message: 88333   

 

as i showed, you have to do it on the fly from u-boot.  use the run command to expand variables into their values.

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