From a0219fbdacc01e039d1b158d16141349a3309915 Mon Sep 17 00:00:00 2001 From: Kalle Jokiniemi Date: Wed, 14 Oct 2009 16:40:37 -0600 Subject: OMAP: Fix race condition with autodeps 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 Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/clockdomain.c | 74 +++++++++++++++++++++++---------------- 1 file changed, 44 insertions(+), 30 deletions(-) (limited to 'arch') diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c index 4ef7b4f5474e..58aff8485df9 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 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 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); -- cgit v1.2.3