[coreboot] How to pass custom defined data from Coreboot to GRUB2

[Mohan Shanmuga Sundaram]

Paul, Thanks for the info!
I looked into CBTABLES, but cannot understand others than CMOS table. It looks simple to me to use CMOS table that I have to define some region for user data in the 'cmos.layout' and use it at GRUB or Ubuntu Linux. But where does CMOS tables really reside? On the boot flash or DDR3?

Regards,
Mohan

-----Original Message-----
From: Paul Menzel [mailto:paulepanter at users.sourceforge.net]
Sent: Monday, October 03, 2016 7:11 PM
To: Mohan Shanmuga Sundaram <mohan.sundaram at aricent.com>
Cc: coreboot at coreboot.org
Subject: Re: [coreboot] How to pass custom defined data from Coreboot to GRUB2

Dear Mohan,


Am Montag, den 03.10.2016, 11:06 +0000 schrieb Mohan Shanmuga Sundaram:
> I have a requirement to pass the state value of a GPIO (on Intel ATOM
> Baytrail SoC) from Coreboot to GRUB2. Based on this GPIO state, I
> would script the GRUB2 to configuration to select an alternative OS
> from the GRUB menu list. Is there a facility to pass this custom
> defined data from Coreboot to GRUB2?

I suggest to use CBTABLES for that. GRUB also can read that.


Thanks,

Paul


[1] grub-core/kern/i386/coreboot/cbtable.c


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