how to disable selfref on IMX8MP?

[jekim]

Hello,

The default value of the PWRCTL register(0x3d400030) was 0x1. It was changed to 0x0 to disable selfref. The reference manual explained selfref_en that If true then the DDRC puts the SDRAM into Self Refresh after a programmable number of cycles "maximum idle clocks before Self Refresh (PWRTMG.selfref_to_x32)". This register bit may be reprogrammed during the course of normal operation. Self refresh events were still found with the selfref_en value 0x0. How to prevent reprogramming of this parameter?

Thanks.

[pengyong_zhang]

hI @jekim 

self refresh is DRAM itself feature in low power mode. And you said auto-refresh is DDRC site feature at DRAM normal mode. Both of refresh features are aim to protect the data. We do not support disabled the self refresh. 

B.R 

[pengyong_zhang · Accepted solution]

Hi @jekim 

we do not support disabled the DRAM self-refresh feature. and why are you want to disable it? disabled it will causa date loss.

B.R 

[jekim]

Hi @pengyong_zhang ,

In failure analysis, enabling and disabling some features are often required. 

Without self refresh, auto-refresh at tREFI period still can protect RAM data. 

Self refresh is not an inevitable mode for RAM operation.

Thanks.