[Intel-wired-lan] [PATCH iwl-net v1] igb: Fix not clearing TimeSync interrupts for 82580

[Vinicius Costa Gomes]

It was reported that 82580 NICs have a hardware bug that makes it
necessary to write into the TSICR (TimeSync Interrupt Cause) register
to clear it.

Add a conditional so only for 82580 we write into the TSICR register,
so we don't risk losing events for other models.

This (partially) reverts commit ee14cc9ea19b ("igb: Fix missing time sync events").

Fixes: ee14cc9ea19b ("igb: Fix missing time sync events")
Reported-by: Daiwei Li <daiweili at gmail.com>
Closes: https://lore.kernel.org/intel-wired-lan/CAN0jFd1kO0MMtOh8N2Ztxn6f7vvDKp2h507sMryobkBKe=xk=w@mail.gmail.com/
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes at intel.com>
---

@Daiwei Li, I don't have a 82580 handy, please confirm that the patch
fixes the issue you are having.

 drivers/net/ethernet/intel/igb/igb_main.c | 27 ++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 11be39f435f3..edb34f67ae03 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6960,31 +6960,48 @@ static void igb_extts(struct igb_adapter *adapter, int tsintr_tt)
 static void igb_tsync_interrupt(struct igb_adapter *adapter)
 {
 	struct e1000_hw *hw = &adapter->hw;
-	u32 tsicr = rd32(E1000_TSICR);
+	u32 ack = 0, tsicr = rd32(E1000_TSICR);
 	struct ptp_clock_event event;
 
 	if (tsicr & TSINTR_SYS_WRAP) {
 		event.type = PTP_CLOCK_PPS;
 		if (adapter->ptp_caps.pps)
 			ptp_clock_event(adapter->ptp_clock, &event);
+		ack |= TSINTR_SYS_WRAP;
 	}
 
 	if (tsicr & E1000_TSICR_TXTS) {
 		/* retrieve hardware timestamp */
 		schedule_work(&adapter->ptp_tx_work);
+		ack |= E1000_TSICR_TXTS;
 	}
 
-	if (tsicr & TSINTR_TT0)
+	if (tsicr & TSINTR_TT0) {
 		igb_perout(adapter, 0);
+		ack |= TSINTR_TT0;
+	}
 
-	if (tsicr & TSINTR_TT1)
+	if (tsicr & TSINTR_TT1) {
 		igb_perout(adapter, 1);
+		ack |= TSINTR_TT1;
+	}
 
-	if (tsicr & TSINTR_AUTT0)
+	if (tsicr & TSINTR_AUTT0) {
 		igb_extts(adapter, 0);
+		ack |= TSINTR_AUTT0;
+	}
 
-	if (tsicr & TSINTR_AUTT1)
+	if (tsicr & TSINTR_AUTT1) {
 		igb_extts(adapter, 1);
+		ack |= TSINTR_AUTT1;
+	}
+
+	if (hw->mac.type == e1000_82580) {
+		/* 82580 has a hardware bug that requires a explicit
+		 * write to clear the TimeSync interrupt cause.
+		 */
+		wr32(E1000_TSICR, ack);
+	}
 }
 
 static irqreturn_t igb_msix_other(int irq, void *data)
-- 
2.45.2