From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Fri, 28 Sep 2018 18:09:23 +0200
Subject: drm/exynos: Use selected dma_dev default iommu domain instead of a
 fake one
Git-commit: 1feda5eb77fc279a4c4eb93b9a0ac3bf7254b57a
Patch-mainline: v4.19-rc7
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Instead of allocating a fake IOMMU domain for all Exynos DRM components,
simply reuse the default IOMMU domain of the already selected DMA device.
This allows some design changes in IOMMU framework without breaking IOMMU
support in Exynos DRM.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/exynos/exynos_drm_iommu.h |   34 +++++-------------------------
 1 file changed, 6 insertions(+), 28 deletions(-)

--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
@@ -55,37 +55,12 @@ static inline void __exynos_iommu_detach
 static inline int __exynos_iommu_create_mapping(struct exynos_drm_private *priv,
 					unsigned long start, unsigned long size)
 {
-	struct iommu_domain *domain;
-	int ret;
-
-	domain = iommu_domain_alloc(priv->dma_dev->bus);
-	if (!domain)
-		return -ENOMEM;
-
-	ret = iommu_get_dma_cookie(domain);
-	if (ret)
-		goto free_domain;
-
-	ret = iommu_dma_init_domain(domain, start, size, NULL);
-	if (ret)
-		goto put_cookie;
-
-	priv->mapping = domain;
+	priv->mapping = iommu_get_domain_for_dev(priv->dma_dev);
 	return 0;
-
-put_cookie:
-	iommu_put_dma_cookie(domain);
-free_domain:
-	iommu_domain_free(domain);
-	return ret;
 }
 
 static inline void __exynos_iommu_release_mapping(struct exynos_drm_private *priv)
 {
-	struct iommu_domain *domain = priv->mapping;
-
-	iommu_put_dma_cookie(domain);
-	iommu_domain_free(domain);
 	priv->mapping = NULL;
 }
 
@@ -94,7 +69,9 @@ static inline int __exynos_iommu_attach(
 {
 	struct iommu_domain *domain = priv->mapping;
 
-	return iommu_attach_device(domain, dev);
+	if (dev != priv->dma_dev)
+		return iommu_attach_device(domain, dev);
+	return 0;
 }
 
 static inline void __exynos_iommu_detach(struct exynos_drm_private *priv,
@@ -102,7 +79,8 @@ static inline void __exynos_iommu_detach
 {
 	struct iommu_domain *domain = priv->mapping;
 
-	iommu_detach_device(domain, dev);
+	if (dev != priv->dma_dev)
+		iommu_detach_device(domain, dev);
 }
 #else
 #error Unsupported architecture and IOMMU/DMA-mapping glue code