+static int check_mirror(unsigned long addr, size_t size)
+{
+ void __iomem *p;
+ int res = -1;
+
+ if (!request_mem_region(addr, size, "arcnet (90xx)"))
+ return -1;
+
+ p = ioremap(addr, size);
+ if (p) {
+ if (readb(p) == TESTvalue)
+ res = 1;
+ else
+ res = 0;
+ iounmap(p);
+ }
+
+ release_mem_region(addr, size);
+ return res;
+}