i.MX8QXP: Get Silicon Revision from Fuses

[philippe_schenk]

Hi,

We would like to differ i.MX8QXP SoCs by their silicon revision (b0, c0) early in the SCFW. As the SCFW itself also detects the silicon revision there should be an undocumented fuse holding that information.

Basically we fuse now user specific information into the SoC user-fuse area. According to that information we then load the correct RAM settings. This is all done in "board_ddr_config". As this function is called by ROM before the SCFW we can only read fuses and not use "SC_C_ID" with "misc_get_control".

Can I read the silicon revision from any fuse? Maybe "OTP_UNIQUE_ID" ?

Best Regards

Philippe

[AldoG · Accepted solution]

Hello,

After double checking with team, unfortunately this fuse (UNIQUE_ID) doesn't provide silicon revision info as far as I know.

The Chip ID and reversion value is inside the SC subsystem, so I'm afarid you have to use "misc_get_control" with "SC_R_SYSTEM" and "SC_C_ID" to get the REV info.

One suggestions will be that you can set the "-dcd skip" in mkimage. Then the ROM will not initialize the DDR, and leave it to SCFW to do the DDR init. And then you can call misc_get_control to do what you want to do.

Hope this helps,

Best regards,

Aldo.

[lidong]

hello;

       we did it  with "-dcd skip",but it doesn't seem to be up or hanging somewhere,and there's no printing.

how should to do if we want to konw the process of the ddr initialize?

[philippe_schenk]

Hi Aldo,

Thanks very much for that answer. We were not aware of this possibility. This sounds indeed like we could do it that way.

Thank you very much!

Best Regards,

Philippe