Re: [PATCH 5/9] clocksource: tegra: Enable ARM arch_timer with TSC

From: Peter De Schrijver
Date: Thu Dec 20 2012 - 17:14:52 EST


> >
> > "tegra114.dtsi" has the folloiwng "tsc" entry. So can we consider that
> > if dts has this entry, CNTFRQ is not set, which implies it's in secure
> > mode. kernel should set it up by itself? Otherwise, skip this setup
> > and use it. For example:
> >
> > tsc {
> > compatible = "nvidia,tegra114-tsc";
> > reg = <0x700f0000 0x20000>;
> > + setup-cntfrq;
> > };
> >
> > Is this what you explained in the above?
> > At least, kernel can survive without bootloader/firmware support, ATM.
>
> No. The DT should only describe the hardware, and not something that is
> Linux specific.
>
> Just use the "clock-frequency" attribute in the timer arch-timer node,
> and get rid of this CNTFRQ setting. The driver already knows how to deal
> with this situation if this attribute is set.

The frequency is probed at boottime by the kernel though. It will not
necessarily be the same for every board.

Cheers,

Peter.
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