On 16/01/18 13:25, Jeffy Chen wrote:
IOMMU drivers are supposed to call this function instead of manually
creating a group in their .add_device callback. This behavior is not
strictly required by ARM DMA mapping implementation, but ARM64 already
relies on it. This patch fixes the rockchip-iommu driver to comply with
this requirement.
FWIW that's not 100% true: what arm64 relies on is the group having a
default DMA ops domain. Technically, you *could* open-code that in the
driver's group allocation, but obviously using the appropriate existing
API is nicer :)
[...]
@@ -1182,6 +1164,29 @@ static void rk_iommu_remove_device(struct device *dev)
iommu_group_remove_device(dev);
}
+static struct iommu_group *rk_iommu_device_group(struct device *dev)
+{
+ struct iommu_group *group;
+ int ret;
+
+ group = iommu_group_get(dev);
+ if (!group) {
This check is pointless - if dev->iommu_group were non-NULL you wouldn't
have been called in the first place.
Robin.
+ group = iommu_group_alloc();
+ if (IS_ERR(group))
+ return group;
+ }
+
+ ret = rk_iommu_group_set_iommudata(group, dev);
+ if (ret)
+ goto err_put_group;
+
+ return group;
+
+err_put_group:
+ iommu_group_put(group);
+ return ERR_PTR(ret);
+}
+
static const struct iommu_ops rk_iommu_ops = {
.domain_alloc = rk_iommu_domain_alloc,
.domain_free = rk_iommu_domain_free,
@@ -1193,6 +1198,7 @@ static const struct iommu_ops rk_iommu_ops = {
.add_device = rk_iommu_add_device,
.remove_device = rk_iommu_remove_device,
.iova_to_phys = rk_iommu_iova_to_phys,
+ .device_group = rk_iommu_device_group,
.pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
};
