TotalMem is lower than the real physical memory on ls2088a

[QiujuYe]

Hi,

I use lsdk1812 to compile ls2088a chip,  and use buildroot to compile root filesystem, but find the TotalMem is about 5g using "free -g", and our ddr memory is total 8G, so I do not know why is less memory so much, and where is the memory allocation? please give me some advice, thanks very much.

Best Regards

Qiuju.ye

[yipingwang · Accepted solution]

The lost DDR can be divided into 2 parts.

1) DDR used by NXP specific software, firmware components

2) DDR used by various segments of kernel.

For the first part,

1) u-boot uses memory till it is used, but once kernel boots, u-boot is swapped out of memory.

2) 66 MB is used by TF-A

3) MC can use anywhere between 512M to 2G (it depends on u-boot comandline argument 'mcmemsize'). The parameter mcmemsize defines amount of system DDR to be used by the Management Complex. If this variable is not defined, the compile-time value 0x70000000 or 1.75GB will be the default. Normally, users do not need to set this variable because the default is acceptable.

TF-A+MC is about 1.8G

kernel reserved=(18620K kernel code, 2476K rwdata, 8844K rodata, 5888K init, 993K bss, 406712K reserved, 327680K cma-reserved) = 771213K=0.7G

[QiujuYe]

Hi yipingwang,

If I modify the mcmemsize to 512M, whether it effects Management Complex to run normally?

Best Regards

Qiuju.ye