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path: root/drivers/base/power/qos.c
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Diffstat (limited to 'drivers/base/power/qos.c')
-rw-r--r--drivers/base/power/qos.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c
index c5d358837461..71855570922d 100644
--- a/drivers/base/power/qos.c
+++ b/drivers/base/power/qos.c
@@ -41,6 +41,7 @@
#include <linux/mutex.h>
#include <linux/export.h>
+#include "power.h"
static DEFINE_MUTEX(dev_pm_qos_mtx);
@@ -166,6 +167,12 @@ void dev_pm_qos_constraints_destroy(struct device *dev)
struct dev_pm_qos_request *req, *tmp;
struct pm_qos_constraints *c;
+ /*
+ * If the device's PM QoS resume latency limit has been exposed to user
+ * space, it has to be hidden at this point.
+ */
+ dev_pm_qos_hide_latency_limit(dev);
+
mutex_lock(&dev_pm_qos_mtx);
dev->power.power_state = PMSG_INVALID;
@@ -445,3 +452,57 @@ int dev_pm_qos_add_ancestor_request(struct device *dev,
return error;
}
EXPORT_SYMBOL_GPL(dev_pm_qos_add_ancestor_request);
+
+#ifdef CONFIG_PM_RUNTIME
+static void __dev_pm_qos_drop_user_request(struct device *dev)
+{
+ dev_pm_qos_remove_request(dev->power.pq_req);
+ dev->power.pq_req = 0;
+}
+
+/**
+ * dev_pm_qos_expose_latency_limit - Expose PM QoS latency limit to user space.
+ * @dev: Device whose PM QoS latency limit is to be exposed to user space.
+ * @value: Initial value of the latency limit.
+ */
+int dev_pm_qos_expose_latency_limit(struct device *dev, s32 value)
+{
+ struct dev_pm_qos_request *req;
+ int ret;
+
+ if (!device_is_registered(dev) || value < 0)
+ return -EINVAL;
+
+ if (dev->power.pq_req)
+ return -EEXIST;
+
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ ret = dev_pm_qos_add_request(dev, req, value);
+ if (ret < 0)
+ return ret;
+
+ dev->power.pq_req = req;
+ ret = pm_qos_sysfs_add(dev);
+ if (ret)
+ __dev_pm_qos_drop_user_request(dev);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_expose_latency_limit);
+
+/**
+ * dev_pm_qos_hide_latency_limit - Hide PM QoS latency limit from user space.
+ * @dev: Device whose PM QoS latency limit is to be hidden from user space.
+ */
+void dev_pm_qos_hide_latency_limit(struct device *dev)
+{
+ if (dev->power.pq_req) {
+ pm_qos_sysfs_remove(dev);
+ __dev_pm_qos_drop_user_request(dev);
+ }
+}
+EXPORT_SYMBOL_GPL(dev_pm_qos_hide_latency_limit);
+#endif /* CONFIG_PM_RUNTIME */