[U-Boot] /proc/cpuinfo Revision field is 0000 on raspberry pi after booting with u-boot

[U-Boot] /proc/cpuinfo Revision field is 0000 on raspberry pi after booting with u-boot

[Christian Erhardt]

Hello,

i'm upcycling an old stereo amplifier and using an raspberry pi to do 
this. Since i didn't want to unscrew the cover everytime i want to do an 
update, i thought booting with u-boot from a secondary partition would 
be a good idea. I'm using buildroot to create a customized kernel / 
system (default raspberry 3.12.y with minor adjustments for my wifi card).

The kernel boots fine and the system is working. The issue is, that when 
i do a 'cat /proc/cpuinfo' the Revision field is set to 0000. When i 
boot the kernel directly, without u-boot, it reports 000e.

The problem is, that the python gpio library is checking this revision 
field to determine the right configuration. So the gpio stuff is not 
working an complaining that my board is not a raspberry pi.

It seems to me, that this issue is related to u-boot, but i have no clue 
why this is happening and what i can do about it.

If i can provide any more information, let me know.

Regards

Christian

[U-Boot] /proc/cpuinfo Revision field is 0000 on raspberry pi after booting with u-boot

[Christian Erhardt]

Hello,

just wanted to let you know, that i found the reason, why this is not 
working:

The raspberry pi passes the revision, serial number, mac address as 
parameters to the kernel during boot. When i start via u-boot, u-boot 
receives this parameters and does not pass them to the kernel. Thats why 
the revision field is empty.

Is there any way to pass parameters given to u-boot on to the kernel?

Regards

Christian


On 09.12.2014 14:01, Christian Erhardt wrote:
> Hello,
>
> i'm upcycling an old stereo amplifier and using an raspberry pi to do 
> this. Since i didn't want to unscrew the cover everytime i want to do 
> an update, i thought booting with u-boot from a secondary partition 
> would be a good idea. I'm using buildroot to create a customized 
> kernel / system (default raspberry 3.12.y with minor adjustments for 
> my wifi card).
>
> The kernel boots fine and the system is working. The issue is, that 
> when i do a 'cat /proc/cpuinfo' the Revision field is set to 0000. 
> When i boot the kernel directly, without u-boot, it reports 000e.
>
> The problem is, that the python gpio library is checking this revision 
> field to determine the right configuration. So the gpio stuff is not 
> working an complaining that my board is not a raspberry pi.
>
> It seems to me, that this issue is related to u-boot, but i have no 
> clue why this is happening and what i can do about it.
>
> If i can provide any more information, let me know.
>
> Regards
>
> Christian
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