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Subject[PATCH v6 6/7] iommu/exynos: Add runtime pm support
Date
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>
---
drivers/iommu/exynos-iommu.c | 45 +++++++++++++++++++++++++++++++++++---------
1 file changed, 36 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index a959443..5e6d7bb 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -206,6 +206,7 @@ struct sysmmu_fault_info {
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 */
};

/*
@@ -594,40 +595,46 @@ 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 = {
@@ -775,7 +782,15 @@ 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);
}

@@ -790,6 +805,7 @@ 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);
@@ -810,6 +826,8 @@ 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);
@@ -822,8 +840,16 @@ static int exynos_iommu_attach_device(struct iommu_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__,
@@ -1200,6 +1226,7 @@ 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;
}

--
1.9.1
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