[PATCH v2 3/8] timer: orion-timer: Add timer_get_boot_us() for BOOTSTAGE support

[Tony Dinh]

Hi Pali,

On Sat, Sep 3, 2022 at 5:02 PM Tony Dinh <mibodhi at gmail.com> wrote:
>
> Hi Stefan,
>
> Sorry, that message was prematurely sent (fat finger). Please see the
> continuation below.
>
> On Sat, Sep 3, 2022 at 4:43 PM Tony Dinh <mibodhi at gmail.com> wrote:
> >
> > Hi Stefan,
> >
> > On Sat, Sep 3, 2022 at 3:44 AM Stefan Roese <sr at denx.de> wrote:
> > >
> > > Hi Tony,
> > >
> > > On 03.09.22 11:44, Tony Dinh wrote:
> > > > Hi Stefan,
> > > >
> > > > On Thu, Sep 1, 2022 at 11:25 PM Stefan Roese <sr at denx.de> wrote:
> > > >>
> > > >> Add timer_get_boot_us() to support boards, that have CONFIG_BOOTSTAGE
> > > >> enabled, like pogo_v4.
> > > >>
> > > >> Signed-off-by: Stefan Roese <sr at denx.de>
> > > >> ---
> > > >> v2:
> > > >> - Change timer_get_boot_us() to use the timer_early functions
> > > >> - Remove #if CONFIG_IS_ENABLED(BOOTSTAGE)
> > > >>
> > > >> Simon, I'm currently looking into this timer_get_boot_us() to using
> > > >> timer_early_get_count() etc consolidation.
> > > >
> > > > Indeed, as you've mentioned above, I think timer_early_get_count() and
> > > > timer_early_get_rate() do need to take into consideration  what the
> > > > input_clock_type is for Kirkwood boards with CONFIG_BOOTSTAGE such as
> > > > the Pogo V4.
> > > >
> > > > I'm seeing on the Pogo V4 test, the timer command reports time about 6
> > > > times slower than it should. It does seem to jive with the fact that
> > > > the Pogo V4 CONFIG_SYS_TCLK is 166Mhz, versus MVEBU 25MHz clock rate.
> > >
> > > Ah, I've missing updating the early functions to also differentiate
> > > between fixed clocks and TCLK timer.
> > >
> > > Please give the attached patch a try - should be applied on top of this
> > > latest patchset.
> >
>
> That looks promising, but I think we are still missing something.
> After applying the attached patch, I ran the test again and it behaved
> the same way (clock rate 6 times slower). So I did another test.
>
> --- Test 1
> Pogo_V4> timer start; sleep 60; timer get; sleep 30; timer get
> 60.000
> 90.000
>
> So apparently the sleep cmd has reset the correct clock rate.
>
> --- Test 2
>
> Pogo_V4> timer start; sleep 30; timer get; sleep 30; timer get
> 30.000
> 60.000
>
> And then wait for 30 seconds, do another "timer get" (I expected to
> see about 90 to 95 seconds).
>
> Pogo_V4> timer get
> 66.237
>
> The different call tree with the timer vs the sleep command made a
> difference. But I could not see where.
>
> --- Test 3
>
> Then I recalled about CONFIG_TIMER_EARLY. It is not selected by
> default in Kconfig currently. So I enabled that to see the behavior.
> But running this build hangs right off the bat. No u-boot version
> banner is printed out.
>

Is there a way to get the CPU frequency from the board upon start up?

Thanks,
Tony