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authorKalle Jokiniemi <kalle.jokiniemi@digia.com>2009-10-14 16:40:37 -0600
committerpaul <paul@twilight.(none)>2009-10-14 16:40:37 -0600
commita0219fbdacc01e039d1b158d16141349a3309915 (patch)
treeba64eb7a8775fc47e5f5d9454810b97988147191
parent161291396e76e0832c08f617eb9bd364d1648148 (diff)
downloadlinux-sh-a0219fbdacc01e039d1b158d16141349a3309915.tar.gz
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 <kalle.jokiniemi@digia.com> Signed-off-by: Paul Walmsley <paul@pwsan.com>
-rw-r--r--arch/arm/mach-omap2/clockdomain.c74
1 files changed, 44 insertions, 30 deletions
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);