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48ccdcd87e
Add support for receive timestamps to the Rx hotpath. This support only works when using the flexible descriptor format, so make sure that we request this format by default if we have receive timestamp support available in the PTP capabilities. In order to report the timestamps to userspace, we need to perform timestamp extension. The Rx descriptor does actually contain the "40 bit" timestamp. However, upper 32 bits which contain nanoseconds are conveniently stored separately in the descriptor. We could extract the 32bits and lower 8 bits, then perform a bitwise OR to calculate the 40bit value. This makes no sense, because the timestamp extension algorithm would simply discard the lower 8 bits anyways. Thus, implement timestamp extension as iavf_ptp_extend_32b_timestamp(), and extract and forward only the 32bits of nominal nanoseconds. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com> Reviewed-by: Sunil Goutham <sgoutham@marvell.com> Reviewed-by: Simon Horman <horms@kernel.org> Tested-by: Rafal Romanowski <rafal.romanowski@intel.com> Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.