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

#define MMAP_BASE        (0x30860000)
#define MMAP_RANGE       (0x100)

int main(int argc, char *argv[])
{
	void *iomap_ptr;
	volatile unsigned int *ptr;
	unsigned int addr, data;
	int fd, i;

	if (!strcmp(argv[1], "-h")) {
		printf("usage:\n");
		printf("   %s r addr addr ...\n", argv[0]);
		printf("   %s w addr data addr data ...\n", argv[0]);
		printf("   addr is offset from 0x%x\n", MMAP_BASE);
		return 1;
	}
	fd = open("/dev/mem", O_RDWR | O_SYNC);
	iomap_ptr = mmap(0, MMAP_RANGE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, MMAP_BASE);
	ptr = (volatile unsigned int *)iomap_ptr;

	if (argv[1][0] == 'r') {
		printf("read register:\n");
		for (i=2; i<argc; i++) {
			addr = strtoul(argv[i], NULL, 16);
			ptr = iomap_ptr + addr;
			printf("[%x]=%x\n", MMAP_BASE+addr, *ptr);
		}
	}
	else {
		printf("write register:\n");
		for (i=2; i<argc; i+=2) {
			addr = strtoul(argv[i], NULL, 16);
			data = strtoul(argv[i+1], NULL, 16);
			ptr = iomap_ptr + addr;
			*ptr = data;
			printf("[%x]=%x\n", MMAP_BASE+addr, data);
		}
		printf("readback register:\n");
		for (i=2; i<argc; i+=2) {
			addr = strtoul(argv[i], NULL, 16);
			ptr = iomap_ptr + addr;
			data = *ptr;
			printf("[%x]=%x\n", MMAP_BASE+addr, data);
		}
	}

	munmap(iomap_ptr, MMAP_RANGE);
	close(fd);
	return 0;
}