From 92c4d8b6f07963bd276dd7b1ecea4e9729491056 Mon Sep 17 00:00:00 2001
From: Peter De Schrijver <pdeschrijver@nvidia.com>
Date: Tue, 12 Feb 2013 17:51:26 +0200
Subject: [PATCH] ARM: tegra: cpuquiet: make userspace governor actions
 synchronous

Userspace expects changes to happen synchronously. Implement this by waiting
with a (configureable) timeout for the action to happen.

Bug 1220065

Change-Id: I81301719707e4baf2b3aea62c38fc771ffe1205d
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-on: http://git-master/r/200013
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>
---
 drivers/cpuquiet/driver.c                     | 8 ++++----
 drivers/cpuquiet/governors/balanced.c         | 4 ++--
 drivers/cpuquiet/governors/runnable_threads.c | 4 ++--
 drivers/cpuquiet/governors/userspace.c        | 8 +++++---
 include/linux/cpuquiet.h                      | 8 ++++----
 5 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/cpuquiet/driver.c b/drivers/cpuquiet/driver.c
index fc83fa8cd022..fb9912b86e5e 100644
--- a/drivers/cpuquiet/driver.c
+++ b/drivers/cpuquiet/driver.c
@@ -106,12 +106,12 @@ static struct kobj_type ktype_cpu_stats = {
 };
 #endif
 
-int cpuquiet_quiesence_cpu(unsigned int cpunumber)
+int cpuquiet_quiesence_cpu(unsigned int cpunumber, bool sync)
 {
 	int err = -EPERM;
 
 	if (cpuquiet_curr_driver && cpuquiet_curr_driver->quiesence_cpu)
-		err = cpuquiet_curr_driver->quiesence_cpu(cpunumber);
+		err = cpuquiet_curr_driver->quiesence_cpu(cpunumber, sync);
 
 #ifdef CONFIG_CPUQUIET_STATS
 	if (!err)
@@ -122,12 +122,12 @@ int cpuquiet_quiesence_cpu(unsigned int cpunumber)
 }
 EXPORT_SYMBOL(cpuquiet_quiesence_cpu);
 
-int cpuquiet_wake_cpu(unsigned int cpunumber)
+int cpuquiet_wake_cpu(unsigned int cpunumber, bool sync)
 {
 	int err = -EPERM;
 
 	if (cpuquiet_curr_driver && cpuquiet_curr_driver->wake_cpu)
-		err = cpuquiet_curr_driver->wake_cpu(cpunumber);
+		err = cpuquiet_curr_driver->wake_cpu(cpunumber, sync);
 
 #ifdef CONFIG_CPUQUIET_STATS
 	if (!err)
diff --git a/drivers/cpuquiet/governors/balanced.c b/drivers/cpuquiet/governors/balanced.c
index f187206ef1c4..794ef1e7e24c 100644
--- a/drivers/cpuquiet/governors/balanced.c
+++ b/drivers/cpuquiet/governors/balanced.c
@@ -341,9 +341,9 @@ static void balanced_work_func(struct work_struct *work)
 	if (cpu < nr_cpu_ids) {
 		last_change_time = now;
 		if (up)
-			cpuquiet_wake_cpu(cpu);
+			cpuquiet_wake_cpu(cpu, false);
 		else
-			cpuquiet_quiesence_cpu(cpu);
+			cpuquiet_quiesence_cpu(cpu, false);
 	}
 }
 
diff --git a/drivers/cpuquiet/governors/runnable_threads.c b/drivers/cpuquiet/governors/runnable_threads.c
index c91d4566a47d..79ba69d8057a 100644
--- a/drivers/cpuquiet/governors/runnable_threads.c
+++ b/drivers/cpuquiet/governors/runnable_threads.c
@@ -190,11 +190,11 @@ static void runnables_work_func(struct work_struct *work)
 	if (action > 0) {
 		cpu = cpumask_next_zero(0, cpu_online_mask);
 		if (cpu < nr_cpu_ids)
-			cpuquiet_wake_cpu(cpu);
+			cpuquiet_wake_cpu(cpu, false);
 	} else if (action < 0) {
 		cpu = get_lightest_loaded_cpu_n();
 		if (cpu < nr_cpu_ids)
-			cpuquiet_quiesence_cpu(cpu);
+			cpuquiet_quiesence_cpu(cpu, false);
 	}
 }
 
diff --git a/drivers/cpuquiet/governors/userspace.c b/drivers/cpuquiet/governors/userspace.c
index 664594d68d8c..12a3d86228ed 100644
--- a/drivers/cpuquiet/governors/userspace.c
+++ b/drivers/cpuquiet/governors/userspace.c
@@ -25,14 +25,16 @@ static DEFINE_MUTEX(userspace_mutex);
 
 static int governor_set(unsigned int cpu, bool active)
 {
+	int err;
+
 	mutex_lock(&userspace_mutex);
 	if (active)
-		cpuquiet_wake_cpu(cpu);
+		err = cpuquiet_wake_cpu(cpu, true);
 	else
-		cpuquiet_quiesence_cpu(cpu);
+		err = cpuquiet_quiesence_cpu(cpu, true);
 	mutex_unlock(&userspace_mutex);
 
-	return 0;
+	return err;
 }
 
 struct cpuquiet_governor userspace_governor = {
diff --git a/include/linux/cpuquiet.h b/include/linux/cpuquiet.h
index 5558c015bb50..1bcfecce3a28 100644
--- a/include/linux/cpuquiet.h
+++ b/include/linux/cpuquiet.h
@@ -37,14 +37,14 @@ struct cpuquiet_governor {
 
 struct cpuquiet_driver {
 	char			name[CPUQUIET_NAME_LEN];
-	int (*quiesence_cpu)	(unsigned int cpunumber);
-	int (*wake_cpu)		(unsigned int cpunumber);
+	int (*quiesence_cpu)	(unsigned int cpunumber, bool sync);
+	int (*wake_cpu)		(unsigned int cpunumber, bool sync);
 };
 
 extern int cpuquiet_register_governor(struct cpuquiet_governor *gov);
 extern void cpuquiet_unregister_governor(struct cpuquiet_governor *gov);
-extern int cpuquiet_quiesence_cpu(unsigned int cpunumber);
-extern int cpuquiet_wake_cpu(unsigned int cpunumber);
+extern int cpuquiet_quiesence_cpu(unsigned int cpunumber, bool sync);
+extern int cpuquiet_wake_cpu(unsigned int cpunumber, bool sync);
 extern int cpuquiet_register_driver(struct cpuquiet_driver *drv);
 extern void cpuquiet_unregister_driver(struct cpuquiet_driver *drv);
 extern int cpuquiet_add_group(struct attribute_group *attrs);
-- 
2.34.1