AnsweredAssumed Answered

Reserve DDR memory block

Question asked by Niklas Molin on Feb 19, 2018
Latest reply on Mar 2, 2018 by igorpadykov

Hi.

I'm doing an application where an external chip will use PCIe bus to store data in i.MX6's DDR memory.

What is the best way to reserve a block of RAM, so Linux can't use this space.

My application (running in the i.MX6) will read the data from this reserved memory location and to do some processing.

I'm trying to update my .dtsi file with:

memory {
   reg = <0x10000000 0x40000000>;
};

reserved-memory {
   #address-cells = <1>;
   #size-cells = <1>;
   ranges;
   dma_reserved: pciebuffer@4ff00000 {
      reg = <0x4ff00000 0x100000>;
   };
};

1. How do I see that this is reserved when running linux (I can only see if I add no-map).

2. If I use no-map, will this memory access be cached when the application tries to read from the DDR?

 

Thanks,

Niklas

Outcomes