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Commit 5e7ff970 authored by Todd Fujinaka's avatar Todd Fujinaka Committed by Jeff Kirsher
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e1000e: 82574/82583 TimeSync errata for SYSTIM read 



Due to a synchronization error, the value read from SYSTIML/SYSTIMH
might be incorrect.

Signed-off-by: default avatarTodd Fujinaka <todd.fujinaka@intel.com>
Tested-by: default avatarAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent b3e5bf1f

drivers/net/ethernet/intel/e1000e/e1000.h

+2 −0
Original line number Diff line number Diff line
@@ -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)

drivers/net/ethernet/intel/e1000e/netdev.c

+26 −1
Original line number Diff line number Diff line
@@ -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;

}