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#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>

int main() {
    int fd;
    void *buffer;
    const char test_string[] = "Hello from DMA buffer!";
    char read_buffer[64];

    // Open the DMA buffer device
    fd = open("/dev/udmabuf0", O_RDWR);
    if (fd < 0) {
        printf("Failed to open /dev/udmabuf0: %s\n", strerror(errno));
        return 1;
    }

    // Map the buffer into user space
    buffer = mmap(NULL, 4194304, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (buffer == MAP_FAILED) {
        printf("Failed to mmap: %s\n", strerror(errno));
        close(fd);
        return 1;
    }

    // Write test string to buffer
    memcpy(buffer, test_string, strlen(test_string) + 1);
    
    // Read back from buffer
    memcpy(read_buffer, buffer, strlen(test_string) + 1);
    
    printf("Written to DMA buffer: %s\n", test_string);
    printf("Read from DMA buffer: %s\n", read_buffer);
    
    // Compare
    if (strcmp(test_string, read_buffer) == 0) {
        printf("Test PASSED - Data matches!\n");
    } else {
        printf("Test FAILED - Data mismatch!\n");
    }

    // Cleanup
    munmap(buffer, 4194304);
    close(fd);
    return 0;
}