LayerscapeのトピックRe: Secure Debug Controller for LS1046A

Secure Debug Controller for LS1046A

Faizanbaig — Tue, 06 Jun 2023 08:53:36 GMT

Hi,

I need few clarifications on Secure debug controller for LS1046A RDB and have few questions :

1) Can Secure debug be enabled without blowing fuses by just writing debug response value to mirror registers?

2)If Secure Debug controller is enabled by blowing the fuses permanently, Is it possible to switch between debug levels like level 1 to Level 0 and level 0 to level 3 and so on.?

Any help/suggestions would be appreciated.

Thanks,
Faizan

Re: Secure Debug Controller for LS1046A

yipingwang — Wed, 07 Jun 2023 02:07:33 GMT

All the fuse are blown once bit. Once you burn a fuse bit from b'0 to a b'1, you cannot turn a fuse b'1 back to a b'0. That is why the
OEM Security Policy Register 1 (SFP_OSPR1), bit 29–31 DBLEV
000 Open: Debug portals are enabled unconditionally.
001 Conditionally closed via challenge response, without notification.
01x 01x: Conditionally closed via challenge response, with notification.
1xx 1xx: Closed. All debug portals are disabled.
instead of use decimal value 1,2,3,4.

Back to Q1, you have to blown the fuse. Burning the debug response value register just prepare the prepare for secure boot. You need to program SFP_OSPR to activate it.

Re: Secure Debug Controller for LS1046A

Faizanbaig — Thu, 29 Jun 2023 06:56:14 GMT

Can we switch between these levels in lab environment?
Like if we enable level 3 , can we go back to level 0 again?

Re: Secure Debug Controller for LS1046A

yipingwang — Mon, 10 Jul 2023 00:29:49 GMT

No, fuse burning is permanent. They cannot switch option back and forth.

Re: Secure Debug Controller for LS1046A

Faizanbaig — Mon, 10 Jul 2023 05:43:23 GMT

Thanks for the response..
Any Mirror registers method or temporary writes?

Re: Secure Debug Controller for LS1046A

yipingwang — Tue, 11 Jul 2023 01:53:33 GMT

No method for temporary writing.

You have to blown the fuse. Burning the debug response value register just prepare the prepare for secure boot. You need to program SFP_OSPR to activate it.