+ /*
+ * We need to read back the CMP register to make sure that
+ * what we wrote hit the chip before we compare it to the
+ * counter.
+ */
+ WARN_ON((u32)hpet_readl(HPET_T0_CMP) != cnt);
+
+ return (s32)((u32)hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0;