How to transfer data from FPGA to HPS DDR

After testing, using the mmap function on the HPS side can read data from HPS DDR. I referred to https://github.com/zangman/de10-nano/blob/master/docs/FPGA-SDRAM-Communication_-Avalon-MM-Host-Master-Component-Part-3.md and used the mmap function to operate on HPS DDR, resulting in the same results as Zangman's.

In cycloneV soc(de10-nano), the starting address of HPS DDR is 0x0000000 and the ending address is 0x3FFFFFFF.

/* code for operating HPS DDR */
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>

#define HPS_DDR_BASE 0x00000000
#define HPS_DDR_SPAN 0x40000000
#define HPS_AXI_BASE 0xC0000000

int main() {
    int fd;
    void *hps_ddr_base;
    void *h2f_base;
    int *addr1;
    int *addr2;

    // Open /dev/mem device
    fd = open("/dev/mem", O_RDWR | O_SYNC);
    if (fd == -1) {
        perror("could not open /dev/mem\n");
        return 1;
    }

   
    hps_ddr_base = mmap(NULL, HPS_DDR_SPAN, PROT_READ | PROT_WRITE, MAP_SHARED, fd, HPS_DDR_BASE);
    h2f_base = mmap(NULL, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, HPS_AXI_BASE);
    
    if (hps_ddr_base == MAP_FAILED) {
        perror("could not mirror HPS DDR3 to user space\n");
        close(fd);
        return 1;
    }

    // Write 0xAA to 0x20000000
    addr1 = (int*)(hps_ddr_base + 0x20000000);
    *addr1 = 0xAA;

    // Write 0x1 to 0xC0000000
    addr2 = (int*)(h2f_base);
    *addr2 = 0x1;

    // Unmap and close the /dev/mem device
    munmap(hps_ddr_base, HPS_DDR_SPAN);
    close(fd);

    return 0;
}

Thank you again for your help. Please close this thread, Adzim.

Regards.