On Wed, 2009-09-16 at 15:07 +0300, Tommi Rantala wrote:
> 2009/9/16 Kalle Jokiniemi <[email protected]>:
> > There is a possible race condition in clockdomain
> > code handling hw supported idle transitions.
> >
> > When multiple autodeps dependencies are being added
> > or removed, a transition of still remaining dependent
> > powerdomain can result in false readings of the
> > state counter. This is especially fatal for off mode
> > state counter, as it could result in a driver not
> > noticing a context loss.
> >
> > Fixed by disabling hw supported state transitions
> > when autodeps are being changed.
> >
> > Signed-off-by: Kalle Jokiniemi <[email protected]>
> > ---
> > arch/arm/mach-omap2/clockdomain.c | 74
> > ++++++++++++++++++++++---------------
> > 1 files changed, 44 insertions(+), 30 deletions(-)
> >
> > diff --git a/arch/arm/mach-omap2/clockdomain.c
> > b/arch/arm/mach-omap2/clockdomain.c
> > index 4ef7b4f..1a8c386 100644
> > --- a/arch/arm/mach-omap2/clockdomain.c
> > +++ b/arch/arm/mach-omap2/clockdomain.c
> > @@ -137,6 +137,36 @@ static void _clkdm_del_autodeps(struct clockdomain
> > *clkdm)
> > }
> > }
> >
> > +/*
> > + * _omap2_clkdm_set_hwsup - set high the hwsup idle transition bit
> > + * @clkdm: struct clockdomain *
> > + * @enable: int 0 to disable, 1 to enable
> > + *
> > + * Internal helper for actually switching the bit that controls hwsup
> > + * idle transitions for clkdm.
> > + */
>
> "static" missing here.
Oops, good catch. I'll repost.
- Kalle
>
> > +void _omap2_clkdm_set_hwsup(struct clockdomain *clkdm, int enable)
> > +{
> > + u32 v;
> > +
> > + if (cpu_is_omap24xx()) {
> > + if (enable)
> > + v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO;
> > + else
> > + v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO;
> > + } else if (cpu_is_omap34xx()) {
> > + if (enable)
> > + v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO;
> > + else
> > + v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO;
> > + } else {
> > + BUG();
> > + }
> > +
> > + cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask,
> > + v << __ffs(clkdm->clktrctrl_mask),
> > + clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL);
> > +}
> >
> > static struct clockdomain *_clkdm_lookup(const char *name)
> > {
> [...]
>
> Regards,
> Tommi Rantala
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