| Message ID | 1253098386-30263-1-git-send-email-kalle.jokiniemi@digia.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Paul Walmsley |
| Headers | show |
2009/9/16 Kalle Jokiniemi <kalle.jokiniemi@digia.com>: > 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 <kalle.jokiniemi@digia.com> > --- > Â arch/arm/mach-omap2/clockdomain.c | Â 74 ++++++++++++++++++++++--------------- > Â 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) > Â Â Â Â } > Â } > > +/* > + * _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. > +void _omap2_clkdm_set_hwsup(struct clockdomain *clkdm, int enable) > +{ > + Â Â Â u32 v; > + > + Â Â Â if (cpu_is_omap24xx()) { > + Â Â Â Â Â Â Â if (enable) > + Â Â Â Â Â Â Â Â Â Â Â v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO; > + Â Â Â Â Â Â Â else > + Â Â Â Â Â Â Â Â Â Â Â v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO; > + Â Â Â } else if (cpu_is_omap34xx()) { > + Â Â Â Â Â Â Â if (enable) > + Â Â Â Â Â Â Â Â Â Â Â v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO; > + Â Â Â Â Â Â Â else > + Â Â Â Â Â Â Â Â Â Â Â v = OMAP34XX_CLKSTCTRL_DISABLE_AUTO; > + Â Â Â } else { > + Â Â Â Â Â Â Â BUG(); > + Â Â Â } > + > + Â Â Â cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, > + Â Â Â Â Â Â Â Â Â Â Â Â Â v << __ffs(clkdm->clktrctrl_mask), > + Â Â Â Â Â Â Â Â Â Â Â Â Â clkdm->pwrdm.ptr->prcm_offs, CM_CLKSTCTRL); > +} > > Â static struct clockdomain *_clkdm_lookup(const char *name) > Â { [...] Regards, Tommi Rantala -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2009-09-16 at 15:07 +0300, Tommi Rantala wrote: > 2009/9/16 Kalle Jokiniemi <kalle.jokiniemi@digia.com>: > > 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 <kalle.jokiniemi@digia.com> > > --- > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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. + */ +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) { @@ -456,8 +486,6 @@ int omap2_clkdm_wakeup(struct clockdomain *clkdm) */ void omap2_clkdm_allow_idle(struct clockdomain *clkdm) { - u32 v; - if (!clkdm) return; @@ -473,18 +501,7 @@ void omap2_clkdm_allow_idle(struct clockdomain *clkdm) if (atomic_read(&clkdm->usecount) > 0) _clkdm_add_autodeps(clkdm); - if (cpu_is_omap24xx()) - v = OMAP24XX_CLKSTCTRL_ENABLE_AUTO; - else if (cpu_is_omap34xx()) - v = OMAP34XX_CLKSTCTRL_ENABLE_AUTO; - else - BUG(); - - - cm_rmw_mod_reg_bits(clkdm->clktrctrl_mask, - v << __ffs(clkdm->clktrctrl_mask), - clkdm->pwrdm.ptr->prcm_offs, - CM_CLKSTCTRL); + _omap2_clkdm_set_hwsup(clkdm, 1); pwrdm_clkdm_state_switch(clkdm); } @@ -500,8 +517,6 @@ void omap2_clkdm_allow_idle(struct clockdomain *clkdm) */ void omap2_clkdm_deny_idle(struct clockdomain *clkdm) { - u32 v; - if (!clkdm) return; @@ -514,16 +529,7 @@ void omap2_clkdm_deny_idle(struct clockdomain *clkdm) pr_debug("clockdomain: disabling automatic idle transitions for %s\n", clkdm->name); - if (cpu_is_omap24xx()) - v = OMAP24XX_CLKSTCTRL_DISABLE_AUTO; - else if (cpu_is_omap34xx()) - 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); + _omap2_clkdm_set_hwsup(clkdm, 0); if (atomic_read(&clkdm->usecount) > 0) _clkdm_del_autodeps(clkdm); @@ -569,10 +575,14 @@ int omap2_clkdm_clk_enable(struct clockdomain *clkdm, struct clk *clk) v = omap2_clkdm_clktrctrl_read(clkdm); if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || - (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) + (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) { + /* Disable HW transitions when we are changing deps */ + _omap2_clkdm_set_hwsup(clkdm, 0); _clkdm_add_autodeps(clkdm); - else + _omap2_clkdm_set_hwsup(clkdm, 1); + } else { omap2_clkdm_wakeup(clkdm); + } pwrdm_wait_transition(clkdm->pwrdm.ptr); pwrdm_clkdm_state_switch(clkdm); @@ -623,10 +633,14 @@ int omap2_clkdm_clk_disable(struct clockdomain *clkdm, struct clk *clk) v = omap2_clkdm_clktrctrl_read(clkdm); if ((cpu_is_omap34xx() && v == OMAP34XX_CLKSTCTRL_ENABLE_AUTO) || - (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) + (cpu_is_omap24xx() && v == OMAP24XX_CLKSTCTRL_ENABLE_AUTO)) { + /* Disable HW transitions when we are changing deps */ + _omap2_clkdm_set_hwsup(clkdm, 0); _clkdm_del_autodeps(clkdm); - else + _omap2_clkdm_set_hwsup(clkdm, 1); + } else { omap2_clkdm_sleep(clkdm); + } pwrdm_clkdm_state_switch(clkdm);
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 <kalle.jokiniemi@digia.com> --- arch/arm/mach-omap2/clockdomain.c | 74 ++++++++++++++++++++++--------------- 1 files changed, 44 insertions(+), 30 deletions(-)