omap: mailbox: fix api used by mailbox to hold a latency constraint

dev_pm_qos API are currently used to hold a latency constraint on
mailbox, which is present in the core power domain. This effectively
holds a constraint on the core power domain.

However, the pm core uses pm_qos APIs to control the latency of the
core domain and thus the C-states in OMAP. The two sets of interfaces
(pm_qos and dev_pm_qos) are de-coupled and thus cannot be used at the
same time to control latency values for core domain.

The mailbox latency code has therefore been modified to use the
pm_qos API for holding latency constraints, so that the pm core
code has a consistent view of the constraints set on core power domain.

Signed-off-by: Subramaniam Chanderashekarapuram <subramaniam.ca@ti.com>
Signed-off-by: Paul Hunt <hunt@ti.com>
Signed-off-by: Suman Anna <s-anna@ti.com>

2 files changed, 22 insertions, 37 deletions

diff --git a/arch/arm/plat-omap/include/plat/mailbox.h b/arch/arm/plat-omap/include/plat/mailbox.h
index 4716d190c141..8e9a44c2a321 100644
--- a/arch/arm/plat-omap/include/plat/mailbox.h
+++ b/arch/arm/plat-omap/include/plat/mailbox.h
@@ -8,7 +8,6 @@
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/kfifo.h>
-#include <linux/pm_qos.h>
 
 typedef u32 mbox_msg_t;
 struct omap_mbox;
@@ -62,7 +61,6 @@ struct omap_mbox {
 	void			*priv;
 	int			use_count;
 	struct blocking_notifier_head   notifier;
-	struct dev_pm_qos_request qos_request;
 	unsigned int		pm_constraint;
 };
 
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 083ce46f38fe..7c616333070b 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -32,6 +32,7 @@
 #include <linux/module.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_qos.h>
 
 #include <plat/mailbox.h>
 
@@ -39,6 +40,10 @@ static struct omap_mbox **mboxes;
 
 static int mbox_configured;
 static DEFINE_MUTEX(mbox_configured_lock);
+static struct pm_qos_request mbox_qos_request;
+
+#define SET_MPU_CORE_CONSTRAINT 10
+#define CLEAR_MPU_CORE_CONSTRAINT PM_QOS_DEFAULT_VALUE
 
 static unsigned int mbox_kfifo_size = CONFIG_OMAP_MBOX_KFIFO_SIZE;
 module_param(mbox_kfifo_size, uint, S_IRUGO);
@@ -294,23 +299,15 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
 {
 	int ret = 0;
 	struct omap_mbox_queue *mq;
-	int fail_constraint = 0;
 
 	mutex_lock(&mbox_configured_lock);
 
 	omap_mbox_enable(mbox);
 
 	if (!mbox_configured++) {
-		if (mbox->pm_constraint) {
-			ret = dev_pm_qos_update_request(&mbox->qos_request,
-					mbox->pm_constraint);
-			if (ret < 0) {
-				fail_constraint = 1;
-				dev_err(mbox->dev,
-					"failed to update qos constraint\n");
-				goto fail_startup;
-			}
-		}
+		if (mbox->pm_constraint)
+			pm_qos_update_request(&mbox_qos_request,
+					SET_MPU_CORE_CONSTRAINT);
 		if (likely(mbox->ops->startup)) {
 			ret = mbox->ops->startup(mbox);
 			if (unlikely(ret))
@@ -364,14 +361,9 @@ fail_alloc_txq:
 		mbox->ops->shutdown(mbox);
 	mbox->use_count--;
 fail_startup:
-	if (!--mbox_configured)
-		if (mbox->pm_constraint && !fail_constraint) {
-			if (dev_pm_qos_update_request(&mbox->qos_request,
-					 PM_QOS_DEFAULT_VALUE) < 0)
-				dev_err(mbox->dev,
-					"failed to relax qos constraint\n");
-
-		}
+	if (!--mbox_configured && mbox->pm_constraint)
+		pm_qos_update_request(&mbox_qos_request,
+					 CLEAR_MPU_CORE_CONSTRAINT);
 	mutex_unlock(&mbox_configured_lock);
 	return ret;
 }
@@ -391,11 +383,9 @@ static void omap_mbox_fini(struct omap_mbox *mbox)
 	if (likely(mbox->ops->shutdown)) {
 		if (!--mbox_configured) {
 			mbox->ops->shutdown(mbox);
-			if (mbox->pm_constraint &&
-				(dev_pm_qos_update_request(&mbox->qos_request,
-						PM_QOS_DEFAULT_VALUE) < 0))
-				dev_err(mbox->dev,
-					"failed to relax qos constraint\n");
+			if (mbox->pm_constraint)
+				pm_qos_update_request(&mbox_qos_request,
+						CLEAR_MPU_CORE_CONSTRAINT);
 		}
 	}
 
@@ -473,11 +463,6 @@ int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 			goto err_out;
 		}
 
-		ret = dev_pm_qos_add_request(parent, &mbox->qos_request,
-						PM_QOS_DEFAULT_VALUE);
-		if (ret < 0)
-			goto err_out;
-
 		BLOCKING_INIT_NOTIFIER_HEAD(&mbox->notifier);
 	}
 
@@ -486,10 +471,8 @@ int omap_mbox_register(struct device *parent, struct omap_mbox **list)
 	return 0;
 
 err_out:
-	while (i--) {
-		dev_pm_qos_remove_request(&mboxes[i]->qos_request);
+	while (i--)
 		device_unregister(mboxes[i]->dev);
-	}
 	return ret;
 }
 EXPORT_SYMBOL(omap_mbox_register);
@@ -501,10 +484,9 @@ int omap_mbox_unregister(struct device *parent)
 	if (!mboxes)
 		return -EINVAL;
 
-	for (i = 0; mboxes[i]; i++) {
-		dev_pm_qos_remove_request(&mboxes[i]->qos_request);
+	for (i = 0; mboxes[i]; i++)
 		device_unregister(mboxes[i]->dev);
-	}
+
 	mboxes = NULL;
 
 	pm_runtime_disable(parent);
@@ -525,12 +507,17 @@ static int __init omap_mbox_init(void)
 	mbox_kfifo_size = ALIGN(mbox_kfifo_size, sizeof(mbox_msg_t));
 	mbox_kfifo_size = max_t(unsigned int, mbox_kfifo_size,
 							sizeof(mbox_msg_t));
+
+	pm_qos_add_request(&mbox_qos_request, PM_QOS_CPU_DMA_LATENCY,
+							PM_QOS_DEFAULT_VALUE);
+
 	return 0;
 }
 subsys_initcall(omap_mbox_init);
 
 static void __exit omap_mbox_exit(void)
 {
+	pm_qos_remove_request(&mbox_qos_request);
 	class_unregister(&omap_mbox_class);
 }
 module_exit(omap_mbox_exit);