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Subject[PATCH 5.8 40/99] igc: Fix wrong timestamp latency numbers
Date
From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

[ Upstream commit f03369b9bfab8e23ac28ca7ab7e6631c374b7cbe ]

The previous timestamping latency numbers were obtained by
interpolating the i210 numbers with the i225 crystal clock value. That
calculation was wrong.

Use the correct values from real measurements.

Fixes: 81b055205e8b ("igc: Add support for RX timestamping")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/igc/igc.h | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h
index 5dbc5a156626a..206b73aa6d7a7 100644
--- a/drivers/net/ethernet/intel/igc/igc.h
+++ b/drivers/net/ethernet/intel/igc/igc.h
@@ -298,18 +298,14 @@ extern char igc_driver_version[];
#define IGC_RX_HDR_LEN IGC_RXBUFFER_256

/* Transmit and receive latency (for PTP timestamps) */
-/* FIXME: These values were estimated using the ones that i225 has as
- * basis, they seem to provide good numbers with ptp4l/phc2sys, but we
- * need to confirm them.
- */
-#define IGC_I225_TX_LATENCY_10 9542
-#define IGC_I225_TX_LATENCY_100 1024
-#define IGC_I225_TX_LATENCY_1000 178
-#define IGC_I225_TX_LATENCY_2500 64
-#define IGC_I225_RX_LATENCY_10 20662
-#define IGC_I225_RX_LATENCY_100 2213
-#define IGC_I225_RX_LATENCY_1000 448
-#define IGC_I225_RX_LATENCY_2500 160
+#define IGC_I225_TX_LATENCY_10 240
+#define IGC_I225_TX_LATENCY_100 58
+#define IGC_I225_TX_LATENCY_1000 80
+#define IGC_I225_TX_LATENCY_2500 1325
+#define IGC_I225_RX_LATENCY_10 6450
+#define IGC_I225_RX_LATENCY_100 185
+#define IGC_I225_RX_LATENCY_1000 300
+#define IGC_I225_RX_LATENCY_2500 1485

/* RX and TX descriptor control thresholds.
* PTHRESH - MAC will consider prefetch if it has fewer than this number of
--
2.25.1


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