iMX8MM - LPDDR4 memory mode register read

[arekkaras]

I need to read some mode registers from LPDDR4 memory with iMX8mm.
I tried to use 'lpddr4_mr_read()' function from ddrphy_utils.c, but this command hangs.
It looks that it accesses registers (DRC_PERF_MON_MRR0_DAT) which are not described in iMX8MM reference manual.
This registers are described in iMX8M reference manual, and it seems that it has the same memory controller as in iMX8MM.

Is there any other way to read LPDDR4 mode registers in imx8mm ?
Reference manual is unclear on this topic.

[igorpadykov]

Hi Arkadiusz

one can look at sect.9.2.3.1.6 Mode Register Read/Write Control Register 0. (MRCTRL0) i.MX8M Mini RM

i.MX 8M Mini Applications Processor Reference Manual

Best regards
igor
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[arekkaras]

I have read reference manual, but there is no any description there how to perform read operation from LPDDR4 mode registers.

Are there any other information available regarding this topic ?

Regards

Arkadiusz

[igorpadykov]

additional details can be found in

sect.9.2 DRC Performance Monitor (DRC_PERF_MON)

i.MX 8M Dual/8M QuadLite/8M Quad Applications Processors Reference Manual 

Best regards
igor