Muhammad Husaini Zulkifli 790835fcc0 igc: Correct the launchtime offset
The launchtime offset should be corrected according to sections 7.5.2.6
Transmit Scheduling Latency of the Intel Ethernet I225/I226 Software
User Manual.

Software can compensate the latency between the transmission scheduling
and the time that packet is transmitted to the network by setting this
GTxOffset register. Without setting this register, there may be a
significant delay between the packet scheduling and the network point.

This patch helps to reduce the latency for each of the link speed.

Before:

10Mbps   : 11000 - 13800 nanosecond
100Mbps  : 1300 - 1700 nanosecond
1000Mbps : 190 - 600 nanosecond
2500Mbps : 1400 - 1700 nanosecond

After:

10Mbps   : less than 750 nanosecond
100Mbps  : less than 192 nanosecond
1000Mbps : less than 128 nanosecond
2500Mbps : less than 128 nanosecond

Test Setup:

Talker : Use l2_tai.c to generate the launchtime into packet payload.
Listener: Use timedump.c to compute the delta between packet arrival and
LaunchTime packet payload.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Muhammad Husaini Zulkifli <muhammad.husaini.zulkifli@intel.com>
Acked-by: Sasha Neftin <sasha.neftin@intel.com>
Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
2022-11-02 11:38:22 -07:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (c) 2020 Intel Corporation */
#ifndef _IGC_TSN_H_
#define _IGC_TSN_H_
int igc_tsn_offload_apply(struct igc_adapter *adapter);
int igc_tsn_reset(struct igc_adapter *adapter);
void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter);
#endif /* _IGC_BASE_H */