tree cb353d5f02e6d1c61c06a10fbdfd8798e41c808b
parent 246d8b184c100e8eb6b4e8c88f232c2ed2a4e672
author Feras Daoud <ferasda@mellanox.com> 1516126120 +0200
committer Doug Ledford <dledford@redhat.com> 1516304961 -0500

net/mlx5e: Add clock info page to mlx5 core devices

Adds a new page to mlx5 core containing clock info data that allows
user level applications to translate between cqe timestamp to
nanoseconds. The information stored into this page is represented
through mlx5_ib_clock_info.

In order to synchronize between kernel and user space a sequence
number is incremented at the beginning and end of each update.
An odd number means the data is being updated while an even means
the access was already done. To guarantee that the data structure
was accessed atomically user will:

repeat:
        seq1 = <read sequence>
        goto <repeate> while odd
        <read data structure>
        seq2 = <read sequence>
        if seq1 != seq2 goto repeat

Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Eitan Rabin <rabin@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>