r128-mmio.c

#include <sys/mman.h>
#include <fcntl.h>
#include <stdio.h>

int main(int argc, char *argv[]) {
  // Run: sudo ./test /sys/bus/pci/devices/*:00:10.0/resource2
  char *file = argv[1];
  fprintf(stderr, "file = %s\n", file);
  int fd = open(file, O_RDWR | O_CLOEXEC);
  fprintf(stderr, "fd = %d\n", fd);
  void *addr = mmap(NULL, 0x4000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  fprintf(stderr, "addr = %p\n", addr);
  perror("error");
  return 0;
}