Yes. EDKII variable assumes the variable storage at a physically map location. 
This is a limitation.

To work with current EDKII variable drivers, for Variable Read, PEI phase also 
require to support it. So, you need to read variable storage to memory in PEI 
Phase, and share it to DXE phase. For Variable Write, only DXE phase requires 
it. So, you can implement FVB protocol to handle the write operation in the 
cached memory and storage.

Thanks
Liming
From: Narinder Dhillon [mailto:[email protected]]
Sent: Friday, October 31, 2014 12:12 PM
To: [email protected]
Subject: [edk2] Non-Volatile Variable Storage

Hi All,

I am attempting to implement a non-volatile variable storage in an eMMC device. 
After about a week of looking around, I have come to the realization that there 
is no such feature in edk2.
Is this correct ?

Looking at 'variable' drivers, it seems that the variable storage for both 
volatile and non are assumed to be at a physically mapped location. I can try 
to load this physical address by reading the block flash device and copying its 
contents to this location before the 'variable' driver starts. I will have to 
implement some shell command to save the changed contents back to flash device.

Does this sound reasonable or is there an easier way ?

Where can I implement this driver to load the non-volatile variable store 
before 'variable' driver starts ?

Thanx.
------------------------------------------------------------------------------
_______________________________________________
edk2-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/edk2-devel

Reply via email to