OMAP2+: clockdomain: Add per clkdm lock to prevent concurrent state programming

Since the clkdm state programming is now done from within the hwmod
framework (which uses a per-hwmod lock) instead of the being done
from the clock framework (which used a global lock), there is now a
need to have per-clkdm locking to prevent races between different
hwmods/modules belonging to the same clock domain concurrently
programming the clkdm state.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/clockdomain.c

@@ -92,6 +92,8 @@ static int _clkdm_register(struct clockdomain *clkdm)
 
 	pwrdm_add_clkdm(pwrdm, clkdm);
 
+	spin_lock_init(&clkdm->lock);
+
 	pr_debug("clockdomain: registered %s\n", clkdm->name);
 
 	return 0;
@@ -690,6 +692,9 @@ int clkdm_clear_all_sleepdeps(struct clockdomain *clkdm)
  */
 int clkdm_sleep(struct clockdomain *clkdm)
 {
+	int ret;
+	unsigned long flags;
+
 	if (!clkdm)
 		return -EINVAL;
 
@@ -704,9 +709,11 @@ int clkdm_sleep(struct clockdomain *clkdm)
 
 	pr_debug("clockdomain: forcing sleep on %s\n", clkdm->name);
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
-
-	return arch_clkdm->clkdm_sleep(clkdm);
+	ret = arch_clkdm->clkdm_sleep(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
+	return ret;
 }
 
 /**
@@ -720,6 +727,9 @@ int clkdm_sleep(struct clockdomain *clkdm)
  */
 int clkdm_wakeup(struct clockdomain *clkdm)
 {
+	int ret;
+	unsigned long flags;
+
 	if (!clkdm)
 		return -EINVAL;
 
@@ -734,9 +744,11 @@ int clkdm_wakeup(struct clockdomain *clkdm)
 
 	pr_debug("clockdomain: forcing wakeup on %s\n", clkdm->name);
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
-
-	return arch_clkdm->clkdm_wakeup(clkdm);
+	ret = arch_clkdm->clkdm_wakeup(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
+	return ret;
 }
 
 /**
@@ -751,6 +763,8 @@ int clkdm_wakeup(struct clockdomain *clkdm)
  */
 void clkdm_allow_idle(struct clockdomain *clkdm)
 {
+	unsigned long flags;
+
 	if (!clkdm)
 		return;
 
@@ -766,10 +780,11 @@ void clkdm_allow_idle(struct clockdomain *clkdm)
 	pr_debug("clockdomain: enabling automatic idle transitions for %s\n",
 		 clkdm->name);
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	clkdm->_flags |= _CLKDM_FLAG_HWSUP_ENABLED;
-
 	arch_clkdm->clkdm_allow_idle(clkdm);
 	pwrdm_clkdm_state_switch(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
 }
 
 /**
@@ -783,6 +798,8 @@ void clkdm_allow_idle(struct clockdomain *clkdm)
  */
 void clkdm_deny_idle(struct clockdomain *clkdm)
 {
+	unsigned long flags;
+
 	if (!clkdm)
 		return;
 
@@ -798,9 +815,10 @@ void clkdm_deny_idle(struct clockdomain *clkdm)
 	pr_debug("clockdomain: disabling automatic idle transitions for %s\n",
 		 clkdm->name);
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	clkdm->_flags &= ~_CLKDM_FLAG_HWSUP_ENABLED;
-
 	arch_clkdm->clkdm_deny_idle(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
 }
 
 /**
@@ -816,16 +834,25 @@ void clkdm_deny_idle(struct clockdomain *clkdm)
  */
 bool clkdm_in_hwsup(struct clockdomain *clkdm)
 {
+	bool ret;
+	unsigned long flags;
+
 	if (!clkdm)
 		return false;
 
-	return (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
+	spin_lock_irqsave(&clkdm->lock, flags);
+	ret = (clkdm->_flags & _CLKDM_FLAG_HWSUP_ENABLED) ? true : false;
+	spin_unlock_irqrestore(&clkdm->lock, flags);
+
+	return ret;
 }
 
 /* Clockdomain-to-clock/hwmod framework interface code */
 
 static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
 {
+	unsigned long flags;
+
 	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_enable)
 		return -EINVAL;
 
@@ -837,9 +864,11 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
 	if ((atomic_inc_return(&clkdm->usecount) > 1) && autodeps)
 		return 0;
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	arch_clkdm->clkdm_clk_enable(clkdm);
 	pwrdm_wait_transition(clkdm->pwrdm.ptr);
 	pwrdm_clkdm_state_switch(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
 
 	pr_debug("clockdomain: clkdm %s: enabled\n", clkdm->name);
 
@@ -848,6 +877,8 @@ static int _clkdm_clk_hwmod_enable(struct clockdomain *clkdm)
 
 static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
 {
+	unsigned long flags;
+
 	if (!clkdm || !arch_clkdm || !arch_clkdm->clkdm_clk_disable)
 		return -EINVAL;
 
@@ -859,8 +890,10 @@ static int _clkdm_clk_hwmod_disable(struct clockdomain *clkdm)
 	if (atomic_dec_return(&clkdm->usecount) > 0)
 		return 0;
 
+	spin_lock_irqsave(&clkdm->lock, flags);
 	arch_clkdm->clkdm_clk_disable(clkdm);
 	pwrdm_clkdm_state_switch(clkdm);
+	spin_unlock_irqrestore(&clkdm->lock, flags);
 
 	pr_debug("clockdomain: clkdm %s: disabled\n", clkdm->name);
 

arch/arm/mach-omap2/clockdomain.h

@@ -17,6 +17,7 @@
 #define __ARCH_ARM_MACH_OMAP2_CLOCKDOMAIN_H
 
 #include <linux/init.h>
+#include <linux/spinlock.h>
 
 #include "powerdomain.h"
 #include <plat/clock.h>
@@ -128,6 +129,7 @@ struct clockdomain {
 	const struct omap_chip_id omap_chip;
 	atomic_t usecount;
 	struct list_head node;
+	spinlock_t lock;
 };
 
 /**

arch/arm/mach-omap2/clockdomain2xxx_3xxx.c

@@ -183,7 +183,8 @@ static int omap2_clkdm_clk_enable(struct clockdomain *clkdm)
 		_clkdm_add_autodeps(clkdm);
 		_enable_hwsup(clkdm);
 	} else {
-		clkdm_wakeup(clkdm);
+		if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
+			omap2_clkdm_wakeup(clkdm);
 	}
 
 	return 0;
@@ -205,7 +206,8 @@ static int omap2_clkdm_clk_disable(struct clockdomain *clkdm)
 		_clkdm_del_autodeps(clkdm);
 		_enable_hwsup(clkdm);
 	} else {
-		clkdm_sleep(clkdm);
+		if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP)
+			omap2_clkdm_sleep(clkdm);
 	}
 
 	return 0;

arch/arm/mach-omap2/clockdomain44xx.c

@@ -95,13 +95,8 @@ static void omap4_clkdm_deny_idle(struct clockdomain *clkdm)
 
 static int omap4_clkdm_clk_enable(struct clockdomain *clkdm)
 {
-	bool hwsup = false;
-
-	hwsup = omap4_cminst_is_clkdm_in_hwsup(clkdm->prcm_partition,
-					clkdm->cm_inst, clkdm->clkdm_offs);
-
-	if (!hwsup)
-		clkdm_wakeup(clkdm);
+	if (clkdm->flags & CLKDM_CAN_FORCE_WAKEUP)
+		return omap4_clkdm_wakeup(clkdm);
 
 	return 0;
 }
@@ -113,8 +108,8 @@ static int omap4_clkdm_clk_disable(struct clockdomain *clkdm)
 	hwsup = omap4_cminst_is_clkdm_in_hwsup(clkdm->prcm_partition,
 					clkdm->cm_inst, clkdm->clkdm_offs);
 
-	if (!hwsup)
-		clkdm_sleep(clkdm);
+	if (!hwsup && (clkdm->flags & CLKDM_CAN_FORCE_SLEEP))
+		omap4_clkdm_sleep(clkdm);
 
 	return 0;
 }