[U-Boot] core ticks/timer code

Wolfgang Denk
2009-03-31T20:46:15Z

Dear Dirk Behme,

In message <49CDCCC1.5050503@googlemail.com> you wrote:
>
> > - get_ticks - return some notion of "cpu ticks"
>
> Yes. Returns the number of cpu ticks since power up. I.e. with 1000
> ticks per second (CONFIG_SYS_HZ) the number of elapsed ms since power up.

Hey. What a chance. We have a wiki. Add that information.

> Yes. Some implementations just return CONFIG_SYS_HZ which is supposed
> to be 1000.

get_ticks() makes no sense to me.

> > - timer_init - setup a core timer
>
> Some implementations do this in interrupt_init(), too.

Let them do it, if they need it, and if they document why they need
it.

> > - get_timer(x) - not really sure what this is supposed to represent, or how
> > "x" is used

See ppc code.

> > - CONFIG_SYS_HZ - no idea how this relates to ticks/timer in U-Boot as in the
> > Linux world, this is the core timer (scheduler) frequency (how many times to
> > execute per second)
>
> CONFIG_SYS_HZ is supposed to be 1000
>
> Does this make sense?

Yes, it makes sense that CONFIG_SYS_HZ is supposed to be 1000.

Best regards,

Wolfgang Denk

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