[PATCH v3 18/20] iommu: Call set_platform_dma if default domain is unavailable

Lu Baolu
2022-11-28T06:57:05Z

If the IOMMU driver has no default domain support, call set_platform_dma
explicitly to return the kernel DMA control back to the platform DMA ops.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/iommu.c | 28 ++++++++--------------------
1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 7c99d8eb3182..e4966f088184 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2040,16 +2040,6 @@ int iommu_deferred_attach(struct device *dev, struct iommu_domain *domain)
return 0;
}

-static void __iommu_detach_device(struct iommu_domain *domain,
- struct device *dev)
-{
- if (iommu_is_attach_deferred(dev))
- return;
-
- domain->ops->detach_dev(domain, dev);
- trace_detach_device_from_domain(dev);
-}
-
void iommu_detach_device(struct iommu_domain *domain, struct device *dev)
{
struct iommu_group *group;
@@ -2154,11 +2144,12 @@ int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group)
}
EXPORT_SYMBOL_GPL(iommu_attach_group);

-static int iommu_group_do_detach_device(struct device *dev, void *data)
+static int iommu_group_do_set_platform_dma(struct device *dev, void *data)
{
- struct iommu_domain *domain = data;
+ const struct iommu_ops *ops = dev_iommu_ops(dev);

- __iommu_detach_device(domain, dev);
+ if (!WARN_ON(!ops->set_platform_dma))
+ ops->set_platform_dma(dev);

return 0;
}
@@ -2172,15 +2163,12 @@ static int __iommu_group_set_domain(struct iommu_group *group,
return 0;

/*
- * New drivers should support default domains and so the detach_dev() op
- * will never be called. Otherwise the NULL domain represents some
- * platform specific behavior.
+ * New drivers should support default domains. Otherwise the NULL
+ * domain represents returning control back to the platform DMA.
*/
if (!new_domain) {
- if (WARN_ON(!group->domain->ops->detach_dev))
- return -EINVAL;
- __iommu_group_for_each_dev(group, group->domain,
- iommu_group_do_detach_device);
+ __iommu_group_for_each_dev(group, NULL,
+ iommu_group_do_set_platform_dma);
group->domain = NULL;
return 0;
}
--
2.34.1