PM QoS: Add disable parameter

For testing purposes it is useful to be able to disable
PM Qos.

Bug 1020898
Bug 917572

Change-Id: I266f5b5730cfe4705197d8b09db7f9eda6766c7c
Signed-off-by: Antti P Miettinen <amiettinen@nvidia.com>
Reviewed-on: http://git-master/r/124667
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Juha Tukkinen <jtukkinen@nvidia.com>

1 files changed, 59 insertions, 2 deletions

diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index 82da7ac3b1f3..c52405ce4d78 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -174,6 +174,8 @@ static const struct file_operations pm_qos_power_fops = {
 	.llseek = noop_llseek,
 };
 
+static bool pm_qos_enabled __read_mostly = true;
+
 /* unlocked internal variant */
 static inline int pm_qos_get_value(struct pm_qos_object *o)
 {
@@ -226,8 +228,11 @@ static void update_target(struct pm_qos_object *o, struct plist_node *node,
 	} else {
 		plist_add(node, &o->requests);
 	}
-	curr_value = pm_qos_get_value(o);
-	pm_qos_set_value(o, curr_value);
+	if (pm_qos_enabled) {
+		curr_value = pm_qos_get_value(o);
+		pm_qos_set_value(o, curr_value);
+	} else
+		curr_value = o->default_value;
 	spin_unlock_irqrestore(&pm_qos_lock, flags);
 
 	if (prev_value != curr_value)
@@ -372,6 +377,58 @@ void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
 }
 EXPORT_SYMBOL_GPL(pm_qos_remove_request);
 
+static int pm_qos_enabled_set(const char *arg, const struct kernel_param *kp)
+{
+	unsigned long flags;
+	bool old;
+	s32 prev[PM_QOS_NUM_CLASSES], curr[PM_QOS_NUM_CLASSES];
+	int ret, i;
+
+	old = pm_qos_enabled;
+	ret = param_set_bool(arg, kp);
+	if (ret != 0) {
+		pr_warn("%s: cannot set PM QoS enable to %s\n",
+			__FUNCTION__, arg);
+		return ret;
+	}
+	spin_lock_irqsave(&pm_qos_lock, flags);
+	for (i = 1; i < PM_QOS_NUM_CLASSES; i++)
+		prev[i] = pm_qos_read_value(pm_qos_array[i]);
+	if (old && !pm_qos_enabled) {
+		/* got disabled */
+		for (i = 1; i < PM_QOS_NUM_CLASSES; i++) {
+			curr[i] = pm_qos_array[i]->default_value;
+			pm_qos_set_value(pm_qos_array[i], curr[i]);
+		}
+	} else if (!old && pm_qos_enabled) {
+		/* got enabled */
+		for (i = 1; i < PM_QOS_NUM_CLASSES; i++) {
+			curr[i] = pm_qos_get_value(pm_qos_array[i]);
+			pm_qos_set_value(pm_qos_array[i], curr[i]);
+		}
+	}
+	spin_unlock_irqrestore(&pm_qos_lock, flags);
+	for (i = 1; i < PM_QOS_NUM_CLASSES; i++)
+		if (prev[i] != curr[i])
+			blocking_notifier_call_chain(
+				pm_qos_array[i]->notifiers,
+				(unsigned long)curr[i],
+				NULL);
+
+	return ret;
+}
+
+static int pm_qos_enabled_get(char *buffer, const struct kernel_param *kp)
+{
+	return param_get_bool(buffer, kp);
+}
+
+static struct kernel_param_ops pm_qos_enabled_ops = {
+	.set = pm_qos_enabled_set,
+	.get = pm_qos_enabled_get,
+};
+module_param_cb(enable, &pm_qos_enabled_ops, &pm_qos_enabled, 0644);
+
 /**
  * pm_qos_add_notifier - sets notification entry for changes to target value
  * @pm_qos_class: identifies which qos target changes should be notified.