On Wednesday 06 April 2022 21:21:59 Marek Behún wrote:
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.
On A385 there is errata only for programming OTP bits.
Are the values you read always the same? Even across power cycles?
Marek
Reading is working fine and is stable also after power cycles. Marvell Internal Use contains data which are same after more reads.