[PATCH v5 7/7] iommu/exynos: Use device dependency links to control runtime pm

[Marek Szyprowski <m.szyprowski@samsung.com>]

This patch uses recently introduced device dependency links to track the
runtime pm state of the master's device. This way each SYSMMU controller
is set to runtime active only when its master's device is active and can
restore or save its state instead of being activated all the time when
attached to the given master device. This way SYSMMU controllers no longer
prevents respective power domains to be turned off when master's device
is not being used.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/iommu/exynos-iommu.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 5e6d7bbf9b70..59b4f2ce4f5f 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -781,10 +781,6 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
 	if (!has_sysmmu(dev) || owner->domain != iommu_domain)
 		return;
 
-	list_for_each_entry(data, &owner->controllers, owner_node) {
-		pm_runtime_put_sync(data->sysmmu);
-	}
-
 	mutex_lock(&owner->rpm_lock);
 
 	list_for_each_entry(data, &owner->controllers, owner_node) {
@@ -848,10 +844,6 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
 
 	mutex_unlock(&owner->rpm_lock);
 
-	list_for_each_entry(data, &owner->controllers, owner_node) {
-		pm_runtime_get_sync(data->sysmmu);
-	}
-
 	dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa\n", __func__,
 		&pagetable);
 
@@ -1232,6 +1224,14 @@ static int exynos_iommu_of_xlate(struct device *dev,
 
 	list_add_tail(&data->owner_node, &owner->controllers);
 	data->master = dev;
+
+	/*
+	 * SYSMMU will be runtime activated via device link (dependency) to its
+	 * master device, so there are no direct calls to pm_runtime_get/put
+	 * in this driver.
+	 */
+	device_link_add(dev, data->sysmmu, DL_FLAG_PM_RUNTIME);
+
 	return 0;
 }
 
-- 
1.9.1