Write/Read RAM memory from FPGA.

So I use the following code in Verilog:

soc_system_onchip_memory2_0 m(
.address(0)
, .byteenable(4'b1111)
, .chipselect(1)
, .clk(FPGA_CLK1_50)
, .clken(1'b1)
, .reset(hps_fpga_reset_n)
, .reset_req(1'b0)
, .write(1'b1)
, .writedata(32'hF0F0F0F0)
, .readdata(datain)
);

1. In my "In-system memory content editor" I can see two Instances, in my second instance I can see these bytes : https://screencast.com/t/yokucok2pkxj

2. On my C code I use /dev/mem with

base = mmap( NULL, HW_REGS_SPAN, ( PROT_READ | PROT_WRITE ), MAP_SHARED, fd, ALT_AXI_FPGASLVS_OFST ); 

where ALT_AXI_FPGASLVS_OFST = 0xC0000000

When I do write bytes trough C with this base I can see it in my FIRST Instance in memory editor : https://screencast.com/t/5w9ljt1jjtp

Please give me advice how can I finally or get bytes from first instance on my FPGA, or how I can bytes from second instance on HPS.

Many thanks!