Messages in this thread | | | Date | Thu, 3 Feb 2022 16:28:13 +0000 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH net] net: stmmac: ensure PTP time register reads are consistent |
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On Thu, Feb 03, 2022 at 05:00:25PM +0100, Yannick Vignon wrote: > From: Yannick Vignon <yannick.vignon@nxp.com> > > Even if protected from preemption and interrupts, a small time window > remains when the 2 register reads could return inconsistent values, > each time the "seconds" register changes. This could lead to an about > 1-second error in the reported time.
Have you checked whether the hardware protects against this (i.o.w. the hardware latches the PTP_STSR value when PTP_STNSR is read, or vice versa? Several PTP devices I've looked at do this to allow consistent reading.
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