topic Re: Memory caching in i.MX8 in i.MX Processors

Memory caching in i.MX8

nxf40256 — Mon, 22 Jul 2019 19:19:23 GMT

I have some questions relate to memory caching in i.MX8 system. I'm working in M4 side

I understand there are two instances/modules for caching

+ MPU in M4 core

+ LMEM in M4 subsystem

Is there any relation between MPU and LMEM. Do they depend on each other?

Is it possible if i enable both MPU and LMEM?

If i configure a DDR region is non-cacheable by MPU and enable LMEM, when i access the memory in non-cacheable region, is the data in the region cached?

Re: Memory caching in i.MX8

Yuri — Wed, 24 Jul 2019 05:52:48 GMT

Hello,

The MPU is M4 core's part and it configures access rules to memory for the core.

The LMEM provides the needed MPU connections for checking all SRAM controller

and cacheable accesses.

Have a great day,

Yuri

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Re: Memory caching in i.MX8

nxf40256 — Wed, 24 Jul 2019 15:37:54 GMT

Hi Yuri,

As my understanding from you, LMEM only checks SRAM region?

Do you have any feedback about below questions?

Is it possible if i enable both MPU and LMEM?

If i configure a DDR region is non-cacheable by MPU and enable LMEM, when i access the memory in non-cacheable region, is the data in the region cached?

Re: Memory caching in i.MX8

Yuri — Thu, 25 Jul 2019 14:06:28 GMT

Hello,

LMEM provides memory controllers for tightly-coupled processor-local memories, that is - for SRAM

and caches.

It is possible to enable both MPU and LMEM.

If one configures a DDR region is non-cacheable by MPU and enable LMEM, the data in the region are not

cached, when accessing the memory in non-cacheable region.

Regards,

Yuri.