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/arm/mach-omap2') diff --git a/arch/arm/mach-omap2/clockdomain.c b/arch/arm/mach-omap2/clockdomain.c index 4ef7b4f5474..58aff8485df 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 From a7f20b2695eb6a00a5464089bacf75b8ed64725e Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Wed, 14 Oct 2009 16:40:37 -0600 Subject: OMAP2xxx clock: set up clockdomain pointer in struct clk clock24xx.c is missing a omap2_init_clk_clkdm() in its omap2_clk_init() function. Among other bad effects, this causes the OMAP hwmod layer to oops on boot. Thanks to Carlos Aguiar and Stefano Panella for reporting this bug. Thanks to Tony Lindgren for N800 booting advice. Signed-off-by: Paul Walmsley Cc: Carlos Aguiar Cc: Stefano Panella Cc: Tony Lindgren --- arch/arm/mach-omap2/clock24xx.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/arm/mach-omap2') diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c index bc5d3ac6661..e2dbedd581e 100644 --- a/arch/arm/mach-omap2/clock24xx.c +++ b/arch/arm/mach-omap2/clock24xx.c @@ -769,6 +769,7 @@ int __init omap2_clk_init(void) if (c->cpu & cpu_mask) { clkdev_add(&c->lk); clk_register(c->lk.clk); + omap2_init_clk_clkdm(c->lk.clk); } /* Check the MPU rate set by bootloader */ -- cgit v1.2.3