Re: [PATCH RFC v2 01/16] ARM: call clk_of_init from time_init

[Sebastian Hesselbarth]

On 08/28/13 00:19, SÃren Brinkmann wrote:
> On Tue, Aug 27, 2013 at 11:27:55PM +0200, Sebastian Hesselbarth wrote:
> > Most DT ARM machs require common clock providers initialized before timers.
> > Currently, arch/arm machs use .init_time to call clk_of_init right before
> > clocksource_of_init. This prevents to remove that hook and use the default
> > hook instead. clk_of_init is safe to call for non-DT platforms, so add
> > the call to ARM arch time_init by default. While at it, also reorder includes
> > alphabetically.
> >
> > Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
> > ---
> > Changelog:
> > v1->v2:
> > - reorder includes alphabetically
> >
> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > Cc: linux-tegra@xxxxxxxxxxxxxxx
> > Cc: kernel@xxxxxxxxxxx
> > Cc: linux-samsung-soc@xxxxxxxxxxxxxxx
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > ---
> >   arch/arm/kernel/time.c |   24 ++++++++++++++----------
> >   1 files changed, 14 insertions(+), 10 deletions(-)
> >
> > diff --git a/arch/arm/kernel/time.c b/arch/arm/kernel/time.c
> > index 98aee32..dd1028e 100644
> > --- a/arch/arm/kernel/time.c
> > +++ b/arch/arm/kernel/time.c
> > @@ -11,25 +11,26 @@
> [ ... ]
> >   void __init time_init(void)
> >   {
> > +	/* initalize common clocks before timers */
> > +	of_clk_init(NULL);
> > +
> >   	if (machine_desc->init_time)
> >   		machine_desc->init_time();
> >   	else
>
> This forces zynq to move some initialization our clock code relies on to
> init_irq(). Also, the current code already takes an approach of
> doing either common init or machine specific init.

Soeren,

you know that patch 16/16 takes care of zynq's clock init?

It's your own patch you provided from the last RFC. Looking at it, it
moves  zynq_sclr_init() to .init_irq and removes the call to
of_clk_init() from zynq_clock_init() which is called by
zynq_sclr_init().

Isn't that solving the above issues for mach-zynq?

> I think it might be better to move the call to of_clk_init() down into
> the else branch of the if-else.

Possibly, yes. But we could also unconditionally call of_clk_init() at
the beginning of time_init() and call clocksource_of_init() at the end.
That will make .init_time() to some fixup hook between initialization of 
clocks and timers.

> Though, this probably contradicts the purpose of the whole series.

Hmm, the purpose was to allow most platforms to remove a custom
.init_time hook only calling of_clk_init() and clocksource_of_init().

If we move of_clk_init() above also in the else-branch the purpose
is still met.

Sebastian

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