drm/exynos: iommu: add support for ARM64 specific code for IOMMU glue

This patch adds support for ARM 64bit architecture with IOMMU-DMA glue
code, so Exynos DRM can be now used on Exynos 5433 with IOMMU enabled.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

3 files changed, 57 insertions, 7 deletions

diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index d814b3048ee5..343813a5fbc8 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -15,7 +15,7 @@ if DRM_EXYNOS
 
 config DRM_EXYNOS_IOMMU
         bool
-        depends on EXYNOS_IOMMU && ARM_DMA_USE_IOMMU
+        depends on EXYNOS_IOMMU
         default y
 
 comment "CRTCs"
diff --git a/drivers/gpu/drm/exynos/exynos_drm_drv.c b/drivers/gpu/drm/exynos/exynos_drm_drv.c
index 13d28d4229e2..877d2efa28e2 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_drv.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_drv.c
@@ -159,12 +159,7 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
         DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
                  dev_name(private->dma_dev));
 
-        /*
-         * create mapping to manage iommu table and set a pointer to iommu
-         * mapping structure to iommu_mapping of private data.
-         * also this iommu_mapping can be used to check if iommu is supported
-         * or not.
-         */
+        /* create common IOMMU mapping for all devices attached to Exynos DRM */
         ret = drm_create_iommu_mapping(dev);
         if (ret < 0) {
                 DRM_ERROR("failed to create iommu mapping.\n");
diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.h b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
index 22e1df2ac62e..c8de4913fdbe 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
@@ -49,6 +49,61 @@ static inline void __exynos_iommu_detach(struct exynos_drm_private *priv,
         arm_iommu_detach_device(dev);
 }
 
+#elif defined(CONFIG_IOMMU_DMA)
+#include <linux/dma-iommu.h>
+
+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);
+        if (ret)
+                goto put_cookie;
+
+        priv->mapping = domain;
+        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;
+}
+
+static inline int __exynos_iommu_attach(struct exynos_drm_private *priv,
+                                        struct device *dev)
+{
+        struct iommu_domain *domain = priv->mapping;
+
+        return iommu_attach_device(domain, dev);
+}
+
+static inline void __exynos_iommu_detach(struct exynos_drm_private *priv,
+                                         struct device *dev)
+{
+        struct iommu_domain *domain = priv->mapping;
+
+        iommu_detach_device(domain, dev);
+}
 #else
 #error Unsupported architecture and IOMMU/DMA-mapping glue code
 #endif