RT1020/RT1050 - PRDB - What is a region lock?

[rshipman]

Hi.

I am using the RT1020, but I am told this document applies:

Security Reference Manual for the i.MX RT1050 Processor, Rev. 1, 04/2018

Regarding:

Table 3-14. Information for encrypted region, pages 79-80

0x0C - 0x0F, Lock_option, Region Lock options:

0 - All regions are unlocked

1 - All FAC regions that belong to BEE Region1 are locked

2 - All RAC regions that belong to BEE Region0 are locked

3 - Both BEE regions are locked, All FAC regions defined in PRDB are locked.

Questions:

1. What is a RAC region? Is this a typo? Should it be FAC?
2. What does it mean by ‘locking’ a region? What does the lock do?
3. Why is a PRDB region able to lock both BEE Region 1 and BEE Region 0? I would have expected PRDB0 to lock BEE Region 0 and PRDB1 to lock BEE Region 1. What am I missing?

Many thanks and regards,

Ronnie

[victorjimenez]

Hello Ronnie, 

What is a RAC region? Is this a typo? Should it be FAC?

This is a typo. I already reported it with the documentation team so they can fix it in future releases. 

What does it mean by ‘locking’ a region? What does the lock do?

I'm currently checking what are all the implications of locking a region, I will give you an update as soon as possible. 

Why is a PRDB region able to lock both BEE Region 1 and BEE Region 0?

This is how the module was designed. Unfortunately, we cannot provide more information. 

Regards, 

Victor 

[victorjimenez]

Hello Ronnie, 

What does it mean by ‘locking’ a region? What does the lock do?

It is r/w block.

Regards, 

Victor