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>

1 files changed, 16 insertions, 0 deletions

diff --git a/include/uapi/rdma/mlx5-abi.h b/include/uapi/rdma/mlx5-abi.h
index f6d319dfc7bf..0299deed71a2 100644
--- a/include/uapi/rdma/mlx5-abi.h
+++ b/include/uapi/rdma/mlx5-abi.h
@@ -381,4 +381,20 @@ struct mlx5_ib_modify_wq {
 	__u32	comp_mask;
 	__u32	reserved;
 };
+
+struct mlx5_ib_clock_info {
+	__u32 sign;
+	__u32 resv;
+	__u64 nsec;
+	__u64 cycles;
+	__u64 frac;
+	__u32 mult;
+	__u32 shift;
+	__u64 mask;
+	__u64 overflow_period;
+};
+
+enum {
+	MLX5_IB_CLOCK_INFO_KERNEL_UPDATING = 1,
+};
 #endif /* MLX5_ABI_USER_H */