/*
 * test program to demonstrate possible cache aliasing problem with O_DRECT
 * option on IDE files.
 *
 * Problem exists on NEC rochopper boards with vr5432/vr5500 CPUs.  However
 * it did not show up with vr4131 cpu and toshiba CPUs, which is unexpected.
 */

#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define IOSIZE  32768

void *aligned_alloc(int size, int align)
{
	void *p = malloc(size + align);
	return (void*) (((unsigned)p + align-1) / align * align);
}

void check_buffer(char *p, int round)
{
	int *q= (int*)p;
	int intsize = IOSIZE / 4;
	int i;
	int base=round*intsize;
	for (i=0; i< intsize; i++, q++)	
		if (*q != base+i) 
			printf("error at (%d, %d): got %d, expect %d\n",
				round, i, *q, base+i);
}

void dcp(int sfd)
{
	int zfd;
	int r, w;
	char *p;
	int round=0;

#if 0
	zfd = open("/dev/zero", O_RDWR);
	p = mmap(NULL, IOSIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE, zfd, 0);
	close(zfd);
#endif
	p = aligned_alloc(IOSIZE, 4096);
	printf("buffer alloced/mapped to memory area: %x\n", p);

	while (1) {
		memset(p, 0, IOSIZE);
		r = read(sfd, p, IOSIZE);
		if (r <= 0) break;
		check_buffer(p, round);
		round++;
	}
}

int
main(int argc, char *argv[])
{
	int sfd;
	int ret;

	sfd = open(argv[1], O_RDONLY | O_DIRECT);
	printf ("sfd ret = %d\n", sfd);
	dcp(sfd);
	return 0;
}