Run the GPIO maps on openWRT

I have a problem with running the program to control GPIO ports on the Openwrt system. As an equipment, I use the ralink mt7628.

I try to compile code but i have problem to run the compiled program. I'm getting error "unable to open mmap file"

I think a problem is in the line with "/dev/mem", but i don't know what i can do...

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>


#define MMAP_PATH   "/dev/mem"


#define RALINK_GPIO_DIR_IN      0
#define RALINK_GPIO_DIR_OUT     1

#define RALINK_REG_PIOINT       0x690
#define RALINK_REG_PIOEDGE      0x6A0
#define RALINK_REG_PIORENA      0x650
#define RALINK_REG_PIOFENA      0x660
#define RALINK_REG_PIODATA      0x620
#define RALINK_REG_PIODIR       0x600
#define RALINK_REG_PIOSET       0x630
#define RALINK_REG_PIORESET     0x640

#define RALINK_REG_PIO6332INT       0x694
#define RALINK_REG_PIO6332EDGE      0x6A4
#define RALINK_REG_PIO6332RENA      0x654
#define RALINK_REG_PIO6332FENA      0x664
#define RALINK_REG_PIO6332DATA      0x624
#define RALINK_REG_PIO6332DIR       0x604
#define RALINK_REG_PIO6332SET       0x634
#define RALINK_REG_PIO6332RESET     0x644

#define RALINK_REG_PIO9564INT       0x698
#define RALINK_REG_PIO9564EDGE      0x6A8
#define RALINK_REG_PIO9564RENA      0x658
#define RALINK_REG_PIO9564FENA      0x668
#define RALINK_REG_PIO9564DATA      0x628
#define RALINK_REG_PIO9564DIR       0x608
#define RALINK_REG_PIO9564SET       0x638
#define RALINK_REG_PIO9564RESET     0x648


static uint8_t* gpio_mmap_reg = NULL;
static int gpio_mmap_fd = 0;

static int gpio_mmap(void)
{
    if ((gpio_mmap_fd = open(MMAP_PATH, O_RDWR)) < 0) {
        fprintf(stderr, "unable to open mmap file");
        return -1;
    }

    gpio_mmap_reg = (uint8_t*) mmap(NULL, 1024, PROT_READ | PROT_WRITE,
        MAP_FILE | MAP_SHARED, gpio_mmap_fd, 0x10000000);
    if (gpio_mmap_reg == MAP_FAILED) {
        perror("foo");
        fprintf(stderr, "failed to mmap");
        gpio_mmap_reg = NULL;
        close(gpio_mmap_fd);
        return -1;
    }

    return 0;
}

int mt76x8_gpio_get_pin(int pin)
{
    uint32_t tmp = 0;

    /* MT7621, MT7628 */
    if (pin <= 31) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIODATA);
        tmp = (tmp >> pin) & 1u;
    } else if (pin <= 63) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO6332DATA);
        tmp = (tmp >> (pin-32)) & 1u;
    } else if (pin <= 95) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO9564DATA);
        tmp = (tmp >> (pin-64)) & 1u;
        tmp = (tmp >> (pin-24)) & 1u;
    }
    return tmp;

}

void mt76x8_gpio_set_pin_direction(int pin, int is_output)
{
    uint32_t tmp;

    /* MT7621, MT7628 */
    if (pin <= 31) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIODIR);
        if (is_output)
            tmp |=  (1u << pin);
        else
            tmp &= ~(1u << pin);
        *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIODIR) = tmp;
    } else if (pin <= 63) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO6332DIR);
        if (is_output)
            tmp |=  (1u << (pin-32));
        else
            tmp &= ~(1u << (pin-32));
        *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO6332DIR) = tmp;
    } else if (pin <= 95) {
        tmp = *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO9564DIR);
        if (is_output)
            tmp |=  (1u << (pin-64));
        else
            tmp &= ~(1u << (pin-64));
        *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO9564DIR) = tmp;
    }
}

void mt76x8_gpio_set_pin_value(int pin, int value)
{
    uint32_t tmp;

    /* MT7621, MT7628 */
    if (pin <= 31) {
        tmp = (1u << pin);
        if (value)
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIOSET) = tmp;
        else
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIORESET) = tmp;
    } else if (pin <= 63) {
        tmp = (1u << (pin-32));
        if (value)
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO6332SET) = tmp;
        else
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO6332RESET) = tmp;
    } else if (pin <= 95) {
        tmp = (1u << (pin-64));
        if (value)
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO9564SET) = tmp;
        else
            *(volatile uint32_t *)(gpio_mmap_reg + RALINK_REG_PIO9564RESET) = tmp;
    }
}

int main(int argc, char **argv)
{
    int ret = -1;

    if (gpio_mmap())
        return -1;

    printf("get pin 39 input %d\n", mt76x8_gpio_get_pin(39));
    printf("get pin 40 input %d\n", mt76x8_gpio_get_pin(40));
    printf("get pin 41 input %d\n", mt76x8_gpio_get_pin(41));
    printf("get pin 42 input %d\n", mt76x8_gpio_get_pin(42));


    printf("set pin 39 output 1\n");
    mt76x8_gpio_set_pin_direction(39, 1);
    mt76x8_gpio_set_pin_value(39, 1);
    printf("set pin 40 output 0\n");
    mt76x8_gpio_set_pin_direction(40, 1);
    mt76x8_gpio_set_pin_value(40, 0);
    printf("set pin 41 output 1\n");
    mt76x8_gpio_set_pin_direction(41, 1);
    mt76x8_gpio_set_pin_value(41, 1);
    printf("set pin 42 output 0\n");
    mt76x8_gpio_set_pin_direction(44, 1);
    mt76x8_gpio_set_pin_value(44, 0);

    while (1)
    {
        mt76x8_gpio_set_pin_value(44, 0);
        mt76x8_gpio_set_pin_value(44, 1);
    }
    close(gpio_mmap_fd);

    return ret;
}