iommu/exynos: Add runtime pm support

This patch adds runtime pm implementation, which is based on previous
suspend/resume code. SYSMMU controller is now being enabled/disabled mainly
from the runtime pm callbacks. System sleep callbacks relies on generic
pm_runtime_force_suspend/pm_runtime_force_resume helpers. To ensure
internal state consistency, additional lock for runtime pm transitions
was introduced.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 0423dff206d4d3d5bf0e6336407a512cf46ab713..22bc7e5c4dcc0e31e4353ce537cac46e7eecdb45 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -237,6 +237,7 @@ static const struct sysmmu_fault_info sysmmu_v5_faults[] = {
 struct exynos_iommu_owner {
        struct list_head controllers;   /* list of sysmmu_drvdata.owner_node */
        struct iommu_domain *domain;    /* domain this device is attached */
+       struct mutex rpm_lock;          /* for runtime pm of all sysmmus */
 };
 
 /*
@@ -632,40 +633,46 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
        return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int exynos_sysmmu_suspend(struct device *dev)
+static int __maybe_unused exynos_sysmmu_suspend(struct device *dev)
 {
        struct sysmmu_drvdata *data = dev_get_drvdata(dev);
        struct device *master = data->master;
 
        if (master) {
-               pm_runtime_put(dev);
+               struct exynos_iommu_owner *owner = master->archdata.iommu;
+
+               mutex_lock(&owner->rpm_lock);
                if (data->domain) {
                        dev_dbg(data->sysmmu, "saving state\n");
                        __sysmmu_disable(data);
                }
+               mutex_unlock(&owner->rpm_lock);
        }
        return 0;
 }
 
-static int exynos_sysmmu_resume(struct device *dev)
+static int __maybe_unused exynos_sysmmu_resume(struct device *dev)
 {
        struct sysmmu_drvdata *data = dev_get_drvdata(dev);
        struct device *master = data->master;
 
        if (master) {
-               pm_runtime_get_sync(dev);
+               struct exynos_iommu_owner *owner = master->archdata.iommu;
+
+               mutex_lock(&owner->rpm_lock);
                if (data->domain) {
                        dev_dbg(data->sysmmu, "restoring state\n");
                        __sysmmu_enable(data);
                }
+               mutex_unlock(&owner->rpm_lock);
        }
        return 0;
 }
-#endif
 
 static const struct dev_pm_ops sysmmu_pm_ops = {
-       SET_LATE_SYSTEM_SLEEP_PM_OPS(exynos_sysmmu_suspend, exynos_sysmmu_resume)
+       SET_RUNTIME_PM_OPS(exynos_sysmmu_suspend, exynos_sysmmu_resume, NULL)
+       SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+                                    pm_runtime_force_resume)
 };
 
 static const struct of_device_id sysmmu_of_match[] __initconst = {
@@ -813,7 +820,15 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
                return;
 
        list_for_each_entry(data, &owner->controllers, owner_node) {
-               __sysmmu_disable(data);
+               pm_runtime_put_sync(data->sysmmu);
+       }
+
+       mutex_lock(&owner->rpm_lock);
+
+       list_for_each_entry(data, &owner->controllers, owner_node) {
+               pm_runtime_get_noresume(data->sysmmu);
+               if (pm_runtime_active(data->sysmmu))
+                       __sysmmu_disable(data);
                pm_runtime_put(data->sysmmu);
        }
 
@@ -828,6 +843,7 @@ static void exynos_iommu_detach_device(struct iommu_domain *iommu_domain,
        owner->domain = NULL;
        spin_unlock_irqrestore(&domain->lock, flags);
 
+       mutex_unlock(&owner->rpm_lock);
 
        dev_dbg(dev, "%s: Detached IOMMU with pgtable %pa\n", __func__,
                &pagetable);
@@ -848,6 +864,8 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
        if (owner->domain)
                exynos_iommu_detach_device(owner->domain, dev);
 
+       mutex_lock(&owner->rpm_lock);
+
        spin_lock_irqsave(&domain->lock, flags);
        list_for_each_entry(data, &owner->controllers, owner_node) {
                spin_lock(&data->lock);
@@ -859,9 +877,17 @@ static int exynos_iommu_attach_device(struct iommu_domain *iommu_domain,
        owner->domain = iommu_domain;
        spin_unlock_irqrestore(&domain->lock, flags);
 
+       list_for_each_entry(data, &owner->controllers, owner_node) {
+               pm_runtime_get_noresume(data->sysmmu);
+               if (pm_runtime_active(data->sysmmu))
+                       __sysmmu_enable(data);
+               pm_runtime_put(data->sysmmu);
+       }
+
+       mutex_unlock(&owner->rpm_lock);
+
        list_for_each_entry(data, &owner->controllers, owner_node) {
                pm_runtime_get_sync(data->sysmmu);
-               __sysmmu_enable(data);
        }
 
        dev_dbg(dev, "%s: Attached IOMMU with pgtable %pa\n", __func__,
@@ -1239,6 +1265,7 @@ static int exynos_iommu_of_xlate(struct device *dev,
                        return -ENOMEM;
 
                INIT_LIST_HEAD(&owner->controllers);
+               mutex_init(&owner->rpm_lock);
                dev->archdata.iommu = owner;
        }