Patch3 - With the low Ethernet connection speed cpdma notification about packet processing can be received before CPTS TX timestamp event, which is set when packet actually left CPSW while cpdma notification is sent when packet pushed in CPSW fifo. As result, when connection is slow and CPU is fast enough TX timestamping is not working properly. Issue was discovered using timestamping tool on am57x boards with Ethernet link speed forced to 100M and on am335x-evm with Ethernet link speed forced to 10M. This series fixes it by introducing TX SKB queue to store PTP SKBs for which Ethernet Transmit Event hasn't been received yet and then re-check this queue with new Ethernet Transmit Events by scheduling CPTS overflow work more often until TX SKB queue is not empty. Patch 1,2 - As CPTS overflow work is time critical task it important to ensure that its scheduling is not delayed. Unfortunately, There could be significant delay in CPTS work schedule under high system load and on -RT which could cause CPTS misbehavior due to internal counter overflow and there is no way to tune CPTS overflow work execution policy and priority manually. The kthread_worker can be used instead of workqueues, as it creates separate named kthread for each worker and its its execution policy and priority can be configured using chrt tool. Instead of modifying CPTS driver itself it was proposed to it was proposed to add PTP auxiliary worker to the PHC subsystem [1], so other drivers can benefit from this feature also. [1] https://www.spinics.net/lists/netdev/msg445392.html changes in v2: - added PTP auxiliary worker to the PHC subsystem Link on v1: - https://www.spinics.net/lists/netdev/msg445387.html Grygorii Strashko (3): ptp: introduce ptp auxiliary worker net: ethernet: ti: cpts: convert to use ptp auxiliary worker net: ethernet: ti: cpts: fix tx timestamping timeout drivers/net/ethernet/ti/cpts.c | 111 +++++++++++++++++++++++++++++++++------ drivers/net/ethernet/ti/cpts.h | 2 +- drivers/ptp/ptp_clock.c | 40 ++++++++++++++ drivers/ptp/ptp_private.h | 3 ++ include/linux/ptp_clock_kernel.h | 19 +++++++ 5 files changed, 158 insertions(+), 17 deletions(-) -- 2.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
