[PATCH v2] iommu/exynos: Fix set_platform_dma_ops() callback

[Marek Szyprowski <m.szyprowski@samsung.com>]

There are some subtle differences between release_device() and
set_platform_dma_ops() callbacks, so separate those two callbacks. Device
links should be removed only in release_device(), because they were
created in probe_device() on purpose and they are needed for proper
Exynos IOMMU driver operation. While fixing this, remove the conditional
code as it is not really needed.

Reported-by: Jason Gunthorpe <jgg@ziepe.ca>
Fixes: 189d496b48b1 ("iommu/exynos: Add missing set_platform_dma_ops callback")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
v2:
- keep set_platform_dma_ops only on ARM 32bit

Some more background why set_platform_dma_ops is needed on ARM 32bit is
available here:
https://lore.kernel.org/all/9a12fcac-c347-5d81-acef-1124c50d0c37@arm.com/
---
 drivers/iommu/exynos-iommu.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 483aaaeb6dae..1abd187c6075 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -1415,23 +1415,26 @@ static struct iommu_device *exynos_iommu_probe_device(struct device *dev)
 	return &data->iommu;
 }
 
-static void exynos_iommu_release_device(struct device *dev)
+static void exynos_iommu_set_platform_dma(struct device *dev)
 {
 	struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
-	struct sysmmu_drvdata *data;
 
 	if (owner->domain) {
 		struct iommu_group *group = iommu_group_get(dev);
 
 		if (group) {
-#ifndef CONFIG_ARM
-			WARN_ON(owner->domain !=
-				iommu_group_default_domain(group));
-#endif
 			exynos_iommu_detach_device(owner->domain, dev);
 			iommu_group_put(group);
 		}
 	}
+}
+
+static void exynos_iommu_release_device(struct device *dev)
+{
+	struct exynos_iommu_owner *owner = dev_iommu_priv_get(dev);
+	struct sysmmu_drvdata *data;
+
+	exynos_iommu_set_platform_dma(dev);
 
 	list_for_each_entry(data, &owner->controllers, owner_node)
 		device_link_del(data->link);
@@ -1479,7 +1482,7 @@ static const struct iommu_ops exynos_iommu_ops = {
 	.domain_alloc = exynos_iommu_domain_alloc,
 	.device_group = generic_device_group,
 #ifdef CONFIG_ARM
-	.set_platform_dma_ops = exynos_iommu_release_device,
+	.set_platform_dma_ops = exynos_iommu_set_platform_dma,
 #endif
 	.probe_device = exynos_iommu_probe_device,
 	.release_device = exynos_iommu_release_device,
-- 
2.34.1