On Wed, Apr 08, 2020 at 02:57:55PM +0530, Jairaj Solanki wrote:
> Can you be a little more specific about the HW "Intel CPU with the ART",
> What does ART mean?
Always Running Timer
Newer Intel CPUs have a clock that is common to the CPU itself and the
PCIe cards. Using the ART, you can correlate the PCIe card's clock
(that is, the PTP time) with the CPU clock. The driver support is
already mainlined:
struct ptp_clock_caps {
...
/* Whether the clock supports precise system-device cross timestamps */
int cross_timestamping;
...
};
This feature effectively provides hardware time stamping between the
PTP clock and the system clock.
Your stated requirement is that the system clock needs to be within
ten nanoseconds of the PTP time. This can only be accomplished with
hardware time stamping.
Unfortunately, the am335x does not offer this capability, AFAICT.
Sorry,
Richard
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