apps/test_mmap/test_mmap.c

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#include <fcntl.h>  /*open*/
#include <unistd.h> /* close, sleep */
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/mman.h>           /* mmap */
#include <string.h> // memcpy


#include <asm/elphel/c313a.h>

//#define D0(x) printf("%s:%d:",__FILE__,__LINE__);x
#define D0(x)


//#define MAP_OPTIONS MAP_FILE|MAP_PRIVATE //Eeeks
#define MAP_OPTIONS MAP_SHARED
int main (int argc, char *argv[]) {
 const char BuffFileName[]="/dev/circbuf";
// const char HeadFileName[]="/dev/jpeghead";
 const char ioctlFileName[]="/dev/sensorpars"; 
// const char trailer[] = {0xff,0xd9};

  int buff_fd, ioctl_fd;
  int sensor_state;
  int frame_number;
  int jpeg_wp, jpeg_rp;
  int buff_size;
  int i,i0, a, alen;
  unsigned long * ccam_dma_buf;                         /* mmapped array */
  int jpeg_len,jpeg_start;
//  int head_fd;
//  int head_size;
//  int jpeg_full_size;
//  char * jpeg_copy;
  int l;
  double tim;
  
  

    ioctl_fd = open(ioctlFileName, O_RDWR);
    if (ioctl_fd<0) { // check control OK
       printf ("Error opening %s\n", ioctlFileName);
       return -1;
    }

// Read current sensor state - defined in c313a.h
    sensor_state = ioctl(ioctl_fd, _IO(CMOSCAM_IOCTYPE, IO_CCAM_MONITOR_SEQ ), 0);
    printf ("Sensor state is %d\n",sensor_state);
    if (sensor_state !=CAMSEQ_RUN)
      printf ("Constant compression is not on. You may use 'fpcf -jpeg a' to start it\n");
// Read current frame number acquired
    frame_number= ioctl(ioctl_fd, _CCCMD( CCAM_RPARS , P_FRAME), 0);
    printf ("Frame number acquired is %d\n",frame_number);

// Read last known (approximately) write pointer (fpga->memory). Actually it is an index in circular buffer array
    jpeg_wp= ioctl(ioctl_fd, _CCCMD( CCAM_RPARS , P_JPEG_WP), 0);
    printf ("Write pointer was 0x%x\n",jpeg_wp);
    close(ioctl_fd); 

    buff_fd = open(BuffFileName, O_RDWR);
    if (buff_fd<0) { // check control OK
       printf ("Error opening %s\n", BuffFileName);
       return -1;
    }
#if 0
#define CIRCLSEEK_TORP  1
#define CIRCLSEEK_TOWP  2
#define CIRCLSEEK_PREV  3
#define CIRCLSEEK_NEXT  4
#define CIRCLSEEK_LAST  5
#define CIRCLSEEK_FIRST 6
#define CIRCLSEEK_SETP  7
#define CIRCLSEEK_VRFY  8
#define CIRCLSEEK_WAIT  9
#endif

// find total buffer length (it is in defines, actually in c313a.h
    buff_size=lseek(buff_fd,0,2);
    jpeg_rp=lseek(buff_fd,CIRCLSEEK_TORP,2);
    if (jpeg_rp<0) { 
        printf ("Read pointer was invalid, recalculating\n");
        jpeg_rp=lseek(buff_fd,CIRCLSEEK_FIRST,2);    
    }
    jpeg_rp =jpeg_rp >> 2; // to words
    printf ("Circular buffer stores %d (0x%x) long values or %d (0x%x bytes), global read pointer is 0x%x\n",(buff_size>>2),(buff_size>>2),buff_size,buff_size, jpeg_rp);
// now let's try mmap itself

D0(sleep(5));
   ccam_dma_buf = (unsigned long *) mmap(0, buff_size, PROT_READ, MAP_OPTIONS, buff_fd, 0);
//   ccam_dma_buf = (unsigned long *) mmap(0, buff_size, PROT_READ, MAP_SHARED, buff_fd, 0);

   if((int)ccam_dma_buf == -1) {
     printf("Error in mmap %s\r\n",BuffFileName);
     close(buff_fd);
     return -1;
   }
// display a portion of the buffer around the jpeg_wp
   printf ("[] shows the value pointed by the last frame's DMA address pointer, <> - length of the last frame,\n" );
   alen=jpeg_wp-9; if (alen<0) alen+= (buff_size>>2);
   i0=(jpeg_wp>>3)<<3;
D0(sleep(5));
   for (i=(i0-64);i<(i0+32);i++) {
     a=i;
     if (i<0) a+=(buff_size>>2);
     else if (i>=(buff_size>>2)) a-=(buff_size>>2);
     if ((i & 7)==0) printf("\n%06x: ",a);
     if      (a==alen) printf("<%08lx>",ccam_dma_buf[a]);
     else if (a==jpeg_wp) printf("[%08lx]",ccam_dma_buf[a]);
     else                 printf(" %08lx ",ccam_dma_buf[a]);
   }
   printf("\n");
D0(sleep(5));

// let's get the last frame here
   jpeg_len=ccam_dma_buf[alen] & 0xffffff; 
   tim=ccam_dma_buf[alen-1];
   tim=ccam_dma_buf[alen-2]+(0.000001*tim);
//   jpeg_start=(alen & 0xfffffff8)- (((jpeg_len+7) & 0xffffffe0)>>2);
   jpeg_start=(alen & 0xfffffff8)- (((jpeg_len + CCAM_MMAP_META + 3) & 0xffffffe0)>>2);
   if (jpeg_start<0) jpeg_start+=(buff_size>>2);
   printf ("JPEG length=%d (0x%x)\n",jpeg_len,jpeg_len);
   printf ("timestamp=%f\n",tim);
   for (i=(jpeg_start-16);i<(jpeg_start+16);i++) {
     a=i;
     if (i<0) a+=(buff_size>>2);
     else if (i>=(buff_size>>2)) a-=(buff_size>>2);
     if ((i & 7)==0) printf("\n%06x: ",a);
     if      (a==jpeg_start) printf("{%08lx}",ccam_dma_buf[a]);
     else                 printf(" %08lx ",ccam_dma_buf[a]);
   }
   printf("\n");

   if (jpeg_rp>=0) {
   printf("\n");
     for (i=(jpeg_rp-16);i<(jpeg_rp+8);i++) {
       a=i;
       if (i<0) a+=(buff_size>>2);
       else if (i>=(buff_size>>2)) a-=(buff_size>>2);
       if ((i & 7)==0) printf("\n%06x: ",a);
       if      (a==jpeg_rp) printf("(%08lx)",ccam_dma_buf[a]);
       else                 printf(" %08lx ",ccam_dma_buf[a]);
     }
     printf("\n");
   }

D0(sleep(5));
   l= munmap(ccam_dma_buf, buff_size);
D0(sleep(5));
   printf ("munmap(0, %d) returned %d\n",buff_size,l);
D0(sleep(5));

   close (buff_fd);              
D0(sleep(5));
   return 0;
}

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