[PATCH 03/11] PM QoS: support the dynamic devices insertion and removal

[jean.pihet@newoldbits.com]

From: Jean Pihet <j-pihet@ti.com>

The devices wake-up latency constraints class of PM QoS is
storing the constraints list using the device pm_info struct.

This patch adds the init and de-init of the per-device constraints
list in order to support the dynamic insertion and removal
of the devices in the system.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
---
 drivers/base/power/main.c     |    8 +++--
 include/linux/pm.h            |    1 +
 include/linux/pm_qos_params.h |    2 +
 kernel/pm_qos_params.c        |   70 ++++++++++++++++++++++++++++++++--------
 4 files changed, 64 insertions(+), 17 deletions(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index b1fd96b..51f5526 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -27,6 +27,7 @@
 #include <linux/sched.h>
 #include <linux/async.h>
 #include <linux/suspend.h>
+#include <linux/pm_qos_params.h>
 
 #include "../base.h"
 #include "power.h"
@@ -96,8 +97,8 @@ void device_pm_add(struct device *dev)
 			dev_name(dev->parent));
 	list_add_tail(&dev->power.entry, &dpm_list);
 	mutex_unlock(&dpm_list_mtx);
-	/* ToDo: call PM QoS to init the per-device wakeup latency constraints */
-	plist_head_init(&dev->power.wakeup_lat_plist_head, &dev->power.lock);
+	/* Call PM QoS to init the per-device wakeup latency constraints */
+	pm_qos_dev_wakeup_lat_init(dev);
 }
 
 /**
@@ -108,7 +109,8 @@ void device_pm_remove(struct device *dev)
 {
 	pr_debug("PM: Removing info for %s:%s\n",
 		 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
-	/* ToDo: call PM QoS to de-init the per-device wakeup latency constraints */
+	/* Call PM QoS to de-init the per-device wakeup latency constraints */
+	pm_qos_dev_wakeup_lat_deinit(dev);
 	complete_all(&dev->power.completion);
 	mutex_lock(&dpm_list_mtx);
 	list_del_init(&dev->power.entry);
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 35fe682..d9b6092 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -464,6 +464,7 @@ struct dev_pm_info {
 	void			*subsys_data;  /* Owned by the subsystem. */
 #endif
 	struct plist_head	wakeup_lat_plist_head;
+	int			wakeup_lat_init;
 };
 
 extern void update_pm_runtime_accounting(struct device *dev);
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
index e6e16cb..5b6707a 100644
--- a/include/linux/pm_qos_params.h
+++ b/include/linux/pm_qos_params.h
@@ -45,4 +45,6 @@ int pm_qos_add_notifier(int class, struct notifier_block *notifier);
 int pm_qos_remove_notifier(int class, struct notifier_block *notifier);
 int pm_qos_request_active(struct pm_qos_request_list *req);
 
+void pm_qos_dev_wakeup_lat_init(struct device *dev);
+void pm_qos_dev_wakeup_lat_deinit(struct device *dev);
 #endif
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index d61c8e5..6f25ccb 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -275,11 +275,21 @@ void pm_qos_add_request(struct pm_qos_request_list *pm_qos_req,
 	struct pm_qos_object *o =  pm_qos_array[pm_qos_params->class];
 	int new_value;
 
-	if ((pm_qos_params->class != PM_QOS_DEV_WAKEUP_LATENCY) &&
-	    (pm_qos_request_active(pm_qos_req))) {
-		WARN(1, KERN_ERR "pm_qos_add_request() called for already "
-		     "added request\n");
-		return;
+	if (pm_qos_params->class == PM_QOS_DEV_WAKEUP_LATENCY) {
+		if (!pm_qos_params->dev) {
+			WARN(1, KERN_ERR "pm_qos_add_request() called for "
+				"invalid device\n");
+			return;
+		}
+		/* Silently return if the device is being released */
+		if (!pm_qos_params->dev->power.wakeup_lat_init)
+			return;
+	} else {
+		if (pm_qos_request_active(pm_qos_req)) {
+			WARN(1, KERN_ERR "pm_qos_add_request() called for "
+				"already added request\n");
+			return;
+		}
 	}
 
 	if (pm_qos_params->value == PM_QOS_DEFAULT_VALUE)
@@ -312,11 +322,16 @@ void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
 	if (!pm_qos_req) /*guard against callers passing in null */
 		return;
 
-	if ((pm_qos_req->class != PM_QOS_DEV_WAKEUP_LATENCY) &&
-	    (!pm_qos_request_active(pm_qos_req))) {
-		WARN(1, KERN_ERR "pm_qos_update_request() called for unknown "
-		     "object\n");
-		return;
+	if (pm_qos_req->class == PM_QOS_DEV_WAKEUP_LATENCY) {
+		/* Silently return if the device is being released */
+		if (!pm_qos_req->dev->power.wakeup_lat_init)
+			return;
+	} else {
+		if (!pm_qos_request_active(pm_qos_req)) {
+			WARN(1, KERN_ERR "pm_qos_update_request() called "
+				"for unknown object\n");
+			return;
+		}
 	}
 
 	if (new_value == PM_QOS_DEFAULT_VALUE)
@@ -343,11 +358,16 @@ void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
 		return;
 		/* silent return to keep pcm code cleaner */
 
-	if ((pm_qos_req->class != PM_QOS_DEV_WAKEUP_LATENCY) &&
-	    (!pm_qos_request_active(pm_qos_req))) {
-		WARN(1, KERN_ERR "pm_qos_remove_request() called for unknown "
-		     "object\n");
+	if (pm_qos_req->class == PM_QOS_DEV_WAKEUP_LATENCY) {
+		/* Silently return if the device is being released */
+		if (!pm_qos_req->dev->power.wakeup_lat_init)
+			return;
+	} else {
+		if (!pm_qos_request_active(pm_qos_req)) {
+			WARN(1, KERN_ERR "pm_qos_remove_request() called "
+				"for unknown object\n");
 		return;
+		}
 	}
 
 	update_target(pm_qos_req, 1, PM_QOS_DEFAULT_VALUE);
@@ -393,6 +413,28 @@ int pm_qos_remove_notifier(int class, struct notifier_block *notifier)
 }
 EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
 
+/* Called from the device PM subsystem at device init */
+void pm_qos_dev_wakeup_lat_init(struct device *dev)
+{
+	plist_head_init(&dev->power.wakeup_lat_plist_head, &dev->power.lock);
+	dev->power.wakeup_lat_init = 1;
+}
+
+/* Called from the device PM subsystem at device release */
+void pm_qos_dev_wakeup_lat_deinit(struct device *dev)
+{
+	struct pm_qos_request_list *req, *tmp;
+
+	dev->power.wakeup_lat_init = 0;
+
+	/* Flush the constraints list for the device */
+	plist_for_each_entry_safe(req, tmp,
+				  &dev->power.wakeup_lat_plist_head,
+				  list)
+		update_target(req, 1, PM_QOS_DEFAULT_VALUE);
+	plist_head_init(&dev->power.wakeup_lat_plist_head, &dev->power.lock);
+}
+
 static int pm_qos_power_open(struct inode *inode, struct file *filp)
 {
 	struct pm_qos_parameters pm_qos_params;
-- 
1.7.4.1