Part Number: AM6421
Tool/software:
Hi TI experts,
I'm using the MCU SDK: mcu_plus_sdk_am64x_10_00_00_20, trying to enable secure boot.
What's the maximum size can be customized used for AM6421's OTP.
I see there's 386bit 'general OTP area' in side the OTP(screenshot as below), so the maximum size is '386bit', right?
Another question is that how can I write and read this 'general OTP area'? can SBL(Non-RTOS app on R5F) can do this? How?
Hi Prashant,
Appreciate your quick response.
After reading the example code, I still have some questions:
1. How to know the corresponding mmrIdx for the extend opt area, as well as 'SMPK' area?
2. From doc 'K3 Security Hardware Architecture - spruim0b.pdf', I saw SBL can read memory mapped regs to get the 'TI-MPK', 'SMPK'
2.1 corresponding memory offset is as following show, right?
2.2 Is this(read from memory maped reg) a suggested method for application to read the customer's public key, so application can do image authentication as well.
2.3 what about 'encryption keys', like 'SMEK', 'TI-MEK', 'BMEK', we can not use 'memory mapped reg' to read out the value, right? also can not read through 'MMR'?
2.4 as my understanding, we can also read from '44237000h' to get all 'extended OPT area', right?
Hi Prashant,
thanks for your detail reply.
2.2) It is recommended to request SYSFW for authentication of any image. The SYSFW performs the authentication against the programmed keys.
About this: what about the decryption? do you also recommend to request SYSFW to use OTP's SMEK to decrypt? and what's the API we can called?
Before I take deep look at AM64's secure solution, I planned to do image authentication and decryption by our own SBL, which planned to use ext OTP area to store our authentication and decryp keys.
But now I'm wondering if this solution is possible, since ext OPT is only 48Bytes. Also after reading 'Bootloader'' code, I suppose decryption is embedded into .rprc image format parsing, so I think it's impossible or hard to do my own decryption, right?
