On 09/03/18 07:11, Vivek Gautam wrote:
On Thu, Mar 8, 2018 at 10:29 AM, Vivek Gautam
<vivek.gautam@xxxxxxxxxxxxxx> wrote:
On Wed, Mar 7, 2018 at 6:17 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote:
On 02/03/18 10:10, Vivek Gautam wrote:
From: Sricharan R <sricharan@xxxxxxxxxxxxxx>
Finally add the device link between the master device and
smmu, so that the smmu gets runtime enabled/disabled only when the
master needs it. This is done from add_device callback which gets
called once when the master is added to the smmu.
Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx>
Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
---
drivers/iommu/arm-smmu.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 3d6a1875431f..bb1ea82c1003 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -217,6 +217,9 @@ struct arm_smmu_device {
/* IOMMU core code handle */
struct iommu_device iommu;
+
+ /* runtime PM link to master */
+ struct device_link *link;
Just the one?
we will either have to count all the devices that are present on the
iommu bus, or
maintain a list to which all the links can be added.
But to add the list, we will have to initialize a LIST_HEAD in struct
device_link
as well.
Or, I think we don't even need to maintain a pointer to link with smmu.
In arm_smmu_remove_device(), we can find out the correct link, and delete it.
list_for_each_entry(link, &dev->links.suppliers, c_node)
if (link->supplier == smmu->dev);
device_link_del(link);
Should that be fine?
Rafael, does the above snippet looks right to you? Context: smmu->dev
is the supplier, and dev is the consumer. We want to find the link,
and delete it.
Actually, looking at the existing code, it seems like device_link_add()
will in fact look up and return any existing link between a given
supplier and consumer - is that intentional API behaviour that users may
rely on to avoid keeping track of explicit link pointers? (or
conversely, might it be reasonable to factor out a device_link_find()
function?)
Robin.
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