topic Re: Resetvector catch in iMX8QM in i.MX Processors

Resetvector catch in iMX8QM

ranjith_tc — Tue, 30 Jun 2020 12:57:03 GMT

Hi,

In the iMX8QM, I am trying to do a reset catch.

For this I am setting the EDECR.RCE to 1 and necessary steps to do the warm reset from software( RMR_ELn.RR=1).

The target is gettting reset, but it is not stopping at reset vector.

Do i need to do anything else to make this happen?

Regards,

ranjith

@‌igorpadykov

Re: Resetvector catch in iMX8QM

igorpadykov — Tue, 30 Jun 2020 13:31:52 GMT

Hi Ranjith

for reset examples one can look at:

imx8.c\platform\user - m4ctrl - M4 Control Tool for i.MX platforms

Please be aware of partition reset. This will reset only a part of the SoC. It does not rerun the ROM
so code will not be reloaded. By default ATF does a partition reset, not a board reset.

https://community.nxp.com/docs/DOC-341481

Best regards
igor
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Re: Resetvector catch in iMX8QM

ranjith_tc — Tue, 30 Jun 2020 21:30:34 GMT

Hi Igor,

I would like to reset the first A53 core and halt it at the reset vector.

For this I am using the RMR_EL2.RR bit.and for catching at the reset, I am setting EDECR.RCE bit.

The core is getting reset and it starts running. So when i check thestatus of EDECR, it has been cleared.

What kind of reset it do when RR is set? A warm reset or cold reset? If it is a warm reset the register should not clear isnt it?

Is ARMv8-A DoPD is implemented in iMX8QM? If it is not, EDECR comes in Debug power domain as per ARM v8-A specification.

So it should not clear even if a cold reset is done. What could be the reason for the register is getting reset?

Regards,

Ranjith

Re: Resetvector catch in iMX8QM

igorpadykov — Tue, 30 Jun 2020 23:55:37 GMT

Hi Ranjith

in i.MX8 series it is not possible to manipulate A53 core directly, it is done through SCU

System Controller Unit (SCU) Introduction for i.MX 8QXP MEK - i.MXDev Blog

Best regards
igor

Re: Resetvector catch in iMX8QM

ranjith_tc — Wed, 01 Jul 2020 10:46:44 GMT

HI,

Thanks Igor for the support.

So, is ther any way to halt the the A53 cores at reset vector in iMX8QM?

regards.

Ranjith

Re: Resetvector catch in iMX8QM

igorpadykov — Wed, 01 Jul 2020 11:36:21 GMT

Hi Ranjith

one can look at documentation included in SCFW Porting Kit

for available reset options.

Best regards
igor