Re: [PATCH 2/2] arm: omap_hwmod disable ick autoidling when a hwmod requires that

[Tero Kristo]

On 08/11/2018 13:08, Andreas Kemnade wrote:
> Hi,
>
> On Thu, 8 Nov 2018 12:26:08 +0200
> Tero Kristo <t-kristo@xxxxxx> wrote:
>
> > On 04/10/2018 23:38, Andreas Kemnade wrote:
> > > Deny autoidle for hwmods with the OCPIF_SWSUP_IDLE flag,
> > > that makes hwmods working properly which cannot handle
> > > autoidle properly in lower power states.
> > > Affected is e. g. the omap_hdq.
> > > Since an ick might have mulitple users, autoidle is disabled
> > > when an individual user requires that rather than in
> > > _setup_iclk_autoidle. dss_ick is an example for that.
> > >
> > > Signed-off-by: Andreas Kemnade <andreas@xxxxxxxxxxxx>
> > > ---
> > >    arch/arm/mach-omap2/omap_hwmod.c | 16 ++++++++++++----
> > >    1 file changed, 12 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
> > > index bb641e6c93d0..0078b0e1d242 100644
> > > --- a/arch/arm/mach-omap2/omap_hwmod.c
> > > +++ b/arch/arm/mach-omap2/omap_hwmod.c
> > > @@ -986,8 +986,10 @@ static int _enable_clocks(struct omap_hwmod *oh)
> > >    		clk_enable(oh->_clk);
> > >    
> > >    	list_for_each_entry(os, &oh->slave_ports, node) {
> > > -		if (os->_clk && (os->flags & OCPIF_SWSUP_IDLE))
> > > +		if (os->_clk && (os->flags & OCPIF_SWSUP_IDLE)) {
> > > +			omap2_clk_deny_idle(os->_clk);
> >
> > I think calling this unconditionally across all platforms / clock types
> > might cause problems. Checking kernel, am33xx seems to have one clock
> > with this flag that is not of omap2 type. Do we have any testing data
> > that this doesn't break things?
> Somehow I have missed that am33xx clock. I have not tested it on that
> platform. Concerning am3xxx I have only a beaglebone block but it not
> am33xx I guess. So I have to recheck I guess.

Beaglebone black is am33xx based device, so you can use that for testing.

> But I think the intention of this flag was to control autoidle
> vs. sw-controlled idle according to...
> [...]
> > >    		if (os->flags & OCPIF_SWSUP_IDLE) {
> > > -			/* XXX omap_iclk_deny_idle(c); */
> > > +			/*
> this comment. So we need a if (clock_is_omap2()) or something like that
> or remove that flag from any other clocks?

You could add check within the omap2_clk_deny_idle / allow_idle calls 
themselves. You can check for presence of flag CLK_IS_BASIC, this is not 
set for omap clocks.

-Tero

> Regards,
> Andreas

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