+/**
+ * e1000e_sanitize_systim - sanitize raw cycle counter reads
+ * @hw: pointer to the HW structure
+ * @systim: cycle_t value read, sanitized and returned
+ *
+ * Errata for 82574/82583 possible bad bits read from SYSTIMH/L:
+ * check to see that the time is incrementing at a reasonable
+ * rate and is a multiple of incvalue.
+ **/
+static cycle_t e1000e_sanitize_systim(struct e1000_hw *hw, cycle_t systim)
+{
+ u64 time_delta, rem, temp;
+ cycle_t systim_next;
+ u32 incvalue;
+ int i;
+
+ incvalue = er32(TIMINCA) & E1000_TIMINCA_INCVALUE_MASK;
+ for (i = 0; i < E1000_MAX_82574_SYSTIM_REREADS; i++) {
+ /* latch SYSTIMH on read of SYSTIML */
+ systim_next = (cycle_t)er32(SYSTIML);
+ systim_next |= (cycle_t)er32(SYSTIMH) << 32;
+
+ time_delta = systim_next - systim;
+ temp = time_delta;
+ /* VMWare users have seen incvalue of zero, don't div / 0 */
+ rem = incvalue ? do_div(temp, incvalue) : (time_delta != 0);
+
+ systim = systim_next;
+
+ if ((time_delta < E1000_82574_SYSTIM_EPSILON) && (rem == 0))
+ break;
+ }
+
+ return systim;
+}
+