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-rw-r--r--drivers/net/ethernet/intel/e1000e/e1000.h2
-rw-r--r--drivers/net/ethernet/intel/e1000e/netdev.c27
2 files changed, 28 insertions, 1 deletions
diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index e27e60910949..63bde99a4ab4 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -391,6 +391,8 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca);
* 25MHz 46-bit 2^46 / 10^9 / 3600 = 19.55 hours
*/
#define E1000_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 60 * 4)
+#define E1000_MAX_82574_SYSTIM_REREADS 50
+#define E1000_82574_SYSTIM_EPSILON (1ULL << 35ULL)
/* hardware capability, feature, and workaround flags */
#define FLAG_HAS_AMT (1 << 0)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 6084e6ba45c2..95cf482cf0af 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -4099,12 +4099,37 @@ static cycle_t e1000e_cyclecounter_read(const struct cyclecounter *cc)
struct e1000_adapter *adapter = container_of(cc, struct e1000_adapter,
cc);
struct e1000_hw *hw = &adapter->hw;
- cycle_t systim;
+ cycle_t systim, systim_next;
/* latch SYSTIMH on read of SYSTIML */
systim = (cycle_t)er32(SYSTIML);
systim |= (cycle_t)er32(SYSTIMH) << 32;
+ if ((hw->mac.type == e1000_82574) || (hw->mac.type == e1000_82583)) {
+ u64 incvalue, time_delta, rem, temp;
+ int i;
+
+ /* 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
+ */
+ 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;
+ rem = do_div(temp, incvalue);
+
+ systim = systim_next;
+
+ if ((time_delta < E1000_82574_SYSTIM_EPSILON) &&
+ (rem == 0))
+ break;
+ }
+ }
return systim;
}