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Now CPTS HW time reading code is implemented in timecounter->cyclecounter .read() callback and performs following operations: timecounter_read() ->cc.read() -> cpts_systim_read() - request current CPTS HW time CPTS_TS_PUSH.TS_PUSH = 1 - poll CPTS FIFO for CPTS_EV_PUSH event with current HW timestamp This approach need to be changed for the future switch to PTP PHC .gettimex64() callback, which require to separate requesting current CPTS HW time and processing CPTS FIFO. And for the follow up patch, which improves .adjfreq() implementation. This patch moves code accessing CPTS HW out of timecounter code as following: - convert HW timestamp of every CPTS event to PTP time (us) and store it as part struct cpts_event; - add CPTS context field to store current CPTS HW time (counter) value and update it on CPTS_EV_PUSH reception; - move code accessing CPTS HW out of timecounter code and use current CPTS HW time (counter) from CPTS context instead; - ensure timecounter->cycle_last is updated on CPTS_EV_PUSH reception. After this change CPTS timecounter will only perform timekeeper role without actually accessing CPTS HW. Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.