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Jacob Keller
712e876371
The E822 hardware for Tx timestamping keeps track of how many outstanding timestamps are still in the PHY memory block. It will not generate a new interrupt to the MAC until all of the timestamps in the region have been read. If somehow all the available data is not read, but the driver has exited its interrupt routine already, the PHY will not generate a new interrupt even if new timestamp data is captured. Because no interrupt is generated, the driver never processes the timestamp data. This state results in a permanent failure for all future Tx timestamps. It is not clear how the driver and hardware could enter this state. However, if it does, there is currently no recovery mechanism. Add a recovery mechanism via the periodic PTP work thread which invokes ice_ptp_periodic_work(). Introduce a new check, ice_ptp_maybe_trigger_tx_interrupt() which checks the PHY timestamp ready bitmask. If any bits are set, trigger a software interrupt by writing to PFINT_OICR. Once triggered, the main timestamp processing thread will read through the PHY data and clear the outstanding timestamp data. Once cleared, new data should trigger interrupts as expected. This should allow recovery from such a state rather than leaving the device in a state where we cannot process Tx timestamps. It is possible that this function checks for timestamp data simultaneously with the interrupt, and it might trigger additional unnecessary interrupts. This will cause a small amount of additional processing. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: Karol Kolacinski <karol.kolacinski@intel.com> Reviewed-by: Andrii Staikov <andrii.staikov@intel.com> Reviewed-by: Simon Horman <horms@kernel.org> Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel) Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com> Signed-off-by: Paolo Abeni <pabeni@redhat.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 Restructured Text 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.