Hi Sricharan,
On 2016-10-24 14:29, Sricharan wrote:
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@xxxxxxxxxxx>
---
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);
+
So in the case of master with multiple sids, this would be called multiple times
for the same master ?
I don't know what is "multiple sids" case, but if given SYSMMU master
device (supplier)
has multiple SYSMMU controllers (consumers), then links will be created
for each SYSMMU
controller. Please note that this code is based on vanilla v4.9-rc1,
which calls
of_xlate() callback only once for every iommu for given master device.
Your IOMMU
deferred probe patches change this, but I already posted a fix for
Exynos IOMMU driver
to handle such case.
By multiple sids, i meant iommus = <&phandle sid1 sid2 .. sidn> case,
so xlate would be called multiples for the same master without deferred
probing also. But the fix that you showed on the other thread would work
here as well or maybe if you dont have masters with multiple sids you wont
have any issues as well.
Exynos SYSMMU driver always use "#iommu-cells = <0>", so it doesn't support
multiple sids. However there is a case with 2 SYSMMU controllers attached
to the same master device: "iommus = <&sysmmu_mfc_l>, <&sysmmu_mfc_r>;".
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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