Re: [PATCH] arm: mvebu: Add support for reading LD0 and LD1 eFuse

Marek Behún
2022-04-06T19:22:07Z

On Wed, 6 Apr 2022 14:18:18 +0200
Pali Rohár <pali@kernel.org> wrote:

> Armada 385 contains 64 lines of HD eFuse and 2 lines of LD eFuse. HD eFuse
> is used for secure boot and each line is 64 bits long + 1 lock bit. LD
> eFuse lines are 256 bits long + 1 lock bit. LD 0 line is reserved for
> Marvell Internal Use and LD 1 line is for General Purpose Data. U-Boot
> already contains HD eFuse reading and programming support.
>
> This patch implements LD eFuse reading support. LD 0 line is mapped to
> U-Boot fuse bank 64 and LD 1 line to fuse bank 65.
>
> LD 0 Marvell Internal Use line seems that was burned in factory with some
> data and can be read by U-Boot fuse command:
>
> => fuse read 64 0 9
>
> LD 1 General Purpose Data line is by default empty and can be read by
> U-Boot fuse command:
>
> => fuse read 65 0 9
>
> Signed-off-by: Pali Rohár <pali@kernel.org>

I am not sure whether this can be used safely on Turris Omnia - there
was some issue with voltage or something, I know for sure that burning
does not work on Omnia, but I am not sure if the issue also prevents
stable reading.

Are the values you read always the same? Even across power cycles?

Marek