topic Relocation of CCSR Memory Region (T1042) in T-Series

Relocation of CCSR Memory Region (T1042)

love_hate_and_repeat — Sat, 19 Oct 2024 23:19:01 GMT

Hello,

After reviewing the "Updating CCSRBARs" section of the T1040 Reference Manual, I have a question regarding the creation of a special, temporary LAW entry for the new CCSR memory region base address.

Why is it necessary to create this temporary LAW entry if we can already configure the CCSRBARH, CCSRBARL, and CCSRAR registers using the old physical address of the CCSR memory region (0xFE00_0000)? The steps stated in the manual is like in the following:

Create a temporary LAW entry.
Set the new base address using the old CCSR physical address.
Delete the temporary LAW entry.

I’m trying to understand the purpose of this law entry(just creating/deleting) —perhaps it's related to the internal logic of the T1042 SoC—but it seems counterintuitive.

Could you provide further insight into why the temporary LAW entry is necessary?

Thank you!

Re: Relocation of CCSR Memory Region (T1042)

yipingwang — Thu, 24 Oct 2024 08:19:14 GMT

No need to a temporary LAW entry for CCSR, you could use the default physical address of the CCSR memory region (0xFE00_0000).'

In CodeWarrior and u-boot, we all use the default physical address 0xFE00_0000.

Re: Relocation of CCSR Memory Region (T1042)

love_hate_and_repeat — Thu, 24 Oct 2024 18:32:33 GMT

sorry but I am not sure you really understand me.

Re: Relocation of CCSR Memory Region (T1042)

yipingwang — Tue, 29 Oct 2024 08:46:17 GMT

Yes, no need to a temporary LAW entry for CCSR.

Re: Relocation of CCSR Memory Region (T1042)

love_hate_and_repeat — Fri, 01 Nov 2024 06:42:48 GMT

According to your answer, I understand that if I want to relocate the CCSR memory region, I do not need to create a temporary LAW entry.

If I didn’t misunderstand you, then the ‘Updating CCSRBARs’ section of T1040 Reference manual should be corrected because it includes information that system programmers do not need.”

Re: Relocation of CCSR Memory Region (T1042)

yipingwang — Tue, 05 Nov 2024 02:44:47 GMT

Your understanding is correct, we will update the reference manual.