test.c

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

int MemoryWrite(off_t offset, size_t size, void *data)
{
    const int N_RETRY = 100;
    const int TIMECYCLE = 1000;
    size_t mem_size = size;
    int cntTimeout;
    int	fd;
    void *ptr;
    int i, err;
    int elapsedMs=0;
    struct timespec start;
    struct timespec stop;
    double speed;

    {
        clock_gettime(CLOCK_REALTIME, &start);

        // open udmabuf device
        fd = open("/dev/udmabuf0", O_RDWR);

        //i = pwrite(fd, data, size, offset);
        err =errno;

        if (fd < 1) {
            fprintf(stderr,"Invalid udmabuf device file\n");
            exit(1);
        }
        // mmap the udmabuf device
        ptr = mmap(NULL, mem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
        if(ptr == MAP_FAILED) {
            fprintf (stderr, "Cannot map udmabuf device.\n");
            fprintf(stderr, "0x%08X, %d\n",errno, errno);
        }

        clock_gettime(CLOCK_REALTIME, &stop);
        elapsedMs = (int)((stop.tv_sec - start.tv_sec) * 1e3 + (stop.tv_nsec - start.tv_nsec) / 1e6);
        printf ("%d ms to map the udmabuf device\n", elapsedMs);
    }

    {
        clock_gettime(CLOCK_REALTIME, &start);

        // move to the requested offset
        ptr = ptr + offset;

        memcpy(ptr,data,size);

        clock_gettime(CLOCK_REALTIME, &stop);
        elapsedMs = (int)((stop.tv_sec - start.tv_sec) * 1e3 + (stop.tv_nsec - start.tv_nsec) / 1e6);    // in milliseconds
        printf ("%d ms to write %zu bytes\n", elapsedMs, size);
        if (elapsedMs > 0) {
            speed = ((size/elapsedMs)/1000);
            printf ("%0.2f MBytes/s\n", speed);
        }
    }

    {
        int     sync_for_device_file;
        int     sync_direction = 2;
        char    attr[1024];
        int     attrlen;
        ssize_t written;
        clock_gettime(CLOCK_REALTIME, &start);
        sync_for_device_file = open("/sys/class/udmabuf/udmabuf0/sync_for_device", O_RDWR);
        if (sync_for_device_file < 0) {
                fprintf(stderr,"Invalid udmabuf sync_for_device file\n");
                exit(1);
        }
        attrlen = sprintf(attr, "1");
        written = write(sync_for_device_file, attr, attrlen);
        close(sync_for_device_file);
        clock_gettime(CLOCK_REALTIME, &stop);
        elapsedMs = (int)((stop.tv_sec - start.tv_sec) * 1e3 + (stop.tv_nsec - start.tv_nsec) / 1e6);
        printf("%d ms to sync  %zu bytes\n", elapsedMs, size);
        if (elapsedMs > 0) {
            speed = ((size/elapsedMs)/1000);
            printf ("%0.2f MBytes/s\n", speed);
        }
    }

    {
        clock_gettime(CLOCK_REALTIME, &start);

        // move back and unmap
        ptr = ptr - offset;

        (void)munmap(ptr, mem_size);

        close(fd);
	
        clock_gettime(CLOCK_REALTIME, &stop);
        elapsedMs = (int)((stop.tv_sec - start.tv_sec) * 1e3 + (stop.tv_nsec - start.tv_nsec) / 1e6);    // in milliseconds
        printf ("%d ms to unmap the udmabuf device\n", elapsedMs);
    }
    return 0;
}

void main()
{
    const size_t size = 42336000;
    void* data;

    data = malloc(size);
    if (NULL == data) {
        fprintf(stderr,"Can not malloc(%zu)\n", size);
        exit(1);
    }
    memset(data, 0, size);
    MemoryWrite(0, 42336000, data);
    free(data);
}

udmabuf_test

root@debian-fpga:/home/fpga/examples/udmabuf_test# insmod /lib/modules/4.19.57-armv7-fpga/ikwzm/udmabuf.ko udmabuf0=42336000
[ 2295.399377] udmabuf udmabuf.0: DMA mask not set
[ 2295.522079] udmabuf udmabuf0: driver version = 1.4.6
[ 2295.527075] udmabuf udmabuf0: major number   = 242
[ 2295.531860] udmabuf udmabuf0: minor number   = 0
[ 2295.536517] udmabuf udmabuf0: phys address   = 0x30100000
[ 2295.541913] udmabuf udmabuf0: buffer size    = 42336256
[ 2295.547183] udmabuf udmabuf0: dma device     = udmabuf.0
[ 2295.552493] udmabuf udmabuf0: dma coherent   = 0
[ 2295.557156] udmabuf udmabuf.0: driver installed.

root@debian-fpga:/home/fpga/examples/udmabuf_test# ./test
0 ms to map the udmabuf device
154 ms to write 42336000 bytes
274.00 MBytes/s
86 ms to sync  42336000 bytes
492.00 MBytes/s
1 ms to unmap the udmabuf device