drm/exynos: add iommu support for exynos drm framework

Changelog v4:
- fix condition to drm_iommu_detach_device funtion.

Changelog v3:
- add dma_parms->max_segment_size setting of drm_device->dev.
- use devm_kzalloc instead of kzalloc.

Changelog v2:
- fix iommu attach condition.
  . check archdata.dma_ops of drm device instead of
    subdrv device's one.
- code clean to exynos_drm_iommu.c file.
  . remove '#ifdef CONFIG_ARM_DMA_USE_IOMMU' from exynos_drm_iommu.c
    and add it to driver/gpu/drm/exynos/Kconfig.

Changelog v1:
This patch adds iommu support for exynos drm framework with dma mapping
api. In this patch, we used dma mapping api to allocate physical memory
and maps it with iommu table and removed some existing codes and added
new some codes for iommu support.

GEM allocation requires one device object to use dma mapping api so
this patch uses one iommu mapping for all sub drivers. In other words,
all sub drivers have same iommu mapping.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/Kconfig

@@ -10,6 +10,12 @@ config DRM_EXYNOS
 	  Choose this option if you have a Samsung SoC EXYNOS chipset.
 	  If M is selected the module will be called exynosdrm.
 
+config DRM_EXYNOS_IOMMU
+	bool "EXYNOS DRM IOMMU Support"
+	depends on DRM_EXYNOS && EXYNOS_IOMMU && ARM_DMA_USE_IOMMU
+	help
+	  Choose this option if you want to use IOMMU feature for DRM.
+
 config DRM_EXYNOS_DMABUF
 	bool "EXYNOS DRM DMABUF"
 	depends on DRM_EXYNOS

drivers/gpu/drm/exynos/Makefile

@@ -8,6 +8,7 @@ exynosdrm-y := exynos_drm_drv.o exynos_drm_encoder.o exynos_drm_connector.o \
 		exynos_drm_buf.o exynos_drm_gem.o exynos_drm_core.o \
 		exynos_drm_plane.o
 
+exynosdrm-$(CONFIG_DRM_EXYNOS_IOMMU) += exynos_drm_iommu.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_DMABUF) += exynos_drm_dmabuf.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_FIMD)	+= exynos_drm_fimd.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_HDMI)	+= exynos_hdmi.o exynos_mixer.o \

drivers/gpu/drm/exynos/exynos_drm_buf.c

@@ -33,71 +33,58 @@
 static int lowlevel_buffer_allocate(struct drm_device *dev,
 		unsigned int flags, struct exynos_drm_gem_buf *buf)
 {
-	dma_addr_t start_addr;
+	int ret = 0;
 	unsigned int npages, i = 0;
 	struct scatterlist *sgl;
-	int ret = 0;
+	enum dma_attr attr = DMA_ATTR_FORCE_CONTIGUOUS;
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
-	if (IS_NONCONTIG_BUFFER(flags)) {
-		DRM_DEBUG_KMS("not support allocation type.\n");
-		return -EINVAL;
-	}
-
 	if (buf->dma_addr) {
 		DRM_DEBUG_KMS("already allocated.\n");
 		return 0;
 	}
 
-	if (buf->size >= SZ_1M) {
-		npages = buf->size >> SECTION_SHIFT;
-		buf->page_size = SECTION_SIZE;
-	} else if (buf->size >= SZ_64K) {
-		npages = buf->size >> 16;
-		buf->page_size = SZ_64K;
-	} else {
-		npages = buf->size >> PAGE_SHIFT;
-		buf->page_size = PAGE_SIZE;
+	init_dma_attrs(&buf->dma_attrs);
+
+	if (flags & EXYNOS_BO_NONCONTIG)
+		attr = DMA_ATTR_WRITE_COMBINE;
+
+	dma_set_attr(attr, &buf->dma_attrs);
+
+	buf->kvaddr = dma_alloc_attrs(dev->dev, buf->size,
+			&buf->dma_addr, GFP_KERNEL, &buf->dma_attrs);
+	if (!buf->kvaddr) {
+		DRM_ERROR("failed to allocate buffer.\n");
+		return -ENOMEM;
 	}
 
 	buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
 	if (!buf->sgt) {
 		DRM_ERROR("failed to allocate sg table.\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_free_attrs;
 	}
 
-	ret = sg_alloc_table(buf->sgt, npages, GFP_KERNEL);
+	ret = dma_get_sgtable(dev->dev, buf->sgt, buf->kvaddr, buf->dma_addr,
+			buf->size);
 	if (ret < 0) {
-		DRM_ERROR("failed to initialize sg table.\n");
-		kfree(buf->sgt);
-		buf->sgt = NULL;
-		return -ENOMEM;
+		DRM_ERROR("failed to get sgtable.\n");
+		goto err_free_sgt;
 	}
 
-	buf->kvaddr = dma_alloc_writecombine(dev->dev, buf->size,
-			&buf->dma_addr, GFP_KERNEL);
-	if (!buf->kvaddr) {
-		DRM_ERROR("failed to allocate buffer.\n");
-		ret = -ENOMEM;
-		goto err1;
-	}
+	npages = buf->sgt->nents;
 
 	buf->pages = kzalloc(sizeof(struct page) * npages, GFP_KERNEL);
 	if (!buf->pages) {
 		DRM_ERROR("failed to allocate pages.\n");
 		ret = -ENOMEM;
-		goto err2;
+		goto err_free_table;
 	}
 
 	sgl = buf->sgt->sgl;
-	start_addr = buf->dma_addr;
-
 	while (i < npages) {
-		buf->pages[i] = phys_to_page(start_addr);
-		sg_set_page(sgl, buf->pages[i], buf->page_size, 0);
-		sg_dma_address(sgl) = start_addr;
-		start_addr += buf->page_size;
+		buf->pages[i] = sg_page(sgl);
 		sgl = sg_next(sgl);
 		i++;
 	}
@@ -108,14 +95,16 @@ static int lowlevel_buffer_allocate(struct drm_device *dev,
 			buf->size);
 
 	return ret;
-err2:
-	dma_free_writecombine(dev->dev, buf->size, buf->kvaddr,
-			(dma_addr_t)buf->dma_addr);
-	buf->dma_addr = (dma_addr_t)NULL;
-err1:
+
+err_free_table:
 	sg_free_table(buf->sgt);
+err_free_sgt:
 	kfree(buf->sgt);
 	buf->sgt = NULL;
+err_free_attrs:
+	dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
+			(dma_addr_t)buf->dma_addr, &buf->dma_attrs);
+	buf->dma_addr = (dma_addr_t)NULL;
 
 	return ret;
 }
@@ -125,16 +114,6 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
 {
 	DRM_DEBUG_KMS("%s.\n", __FILE__);
 
-	/*
-	 * release only physically continuous memory and
-	 * non-continuous memory would be released by exynos
-	 * gem framework.
-	 */
-	if (IS_NONCONTIG_BUFFER(flags)) {
-		DRM_DEBUG_KMS("not support allocation type.\n");
-		return;
-	}
-
 	if (!buf->dma_addr) {
 		DRM_DEBUG_KMS("dma_addr is invalid.\n");
 		return;
@@ -150,11 +129,8 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev,
 	kfree(buf->sgt);
 	buf->sgt = NULL;
 
-	kfree(buf->pages);
-	buf->pages = NULL;
-
-	dma_free_writecombine(dev->dev, buf->size, buf->kvaddr,
-				(dma_addr_t)buf->dma_addr);
+	dma_free_attrs(dev->dev, buf->size, buf->kvaddr,
+				(dma_addr_t)buf->dma_addr, &buf->dma_attrs);
 	buf->dma_addr = (dma_addr_t)NULL;
 }
 

drivers/gpu/drm/exynos/exynos_drm_dmabuf.c

@@ -30,29 +30,31 @@
 
 #include <linux/dma-buf.h>
 
-static struct sg_table *exynos_pages_to_sg(struct page **pages, int nr_pages,
-		unsigned int page_size)
+static struct sg_table *exynos_get_sgt(struct drm_device *drm_dev,
+					struct exynos_drm_gem_buf *buf)
 {
 	struct sg_table *sgt = NULL;
-	struct scatterlist *sgl;
-	int i, ret;
+	int ret;
 
 	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
 	if (!sgt)
 		goto out;
 
-	ret = sg_alloc_table(sgt, nr_pages, GFP_KERNEL);
+	ret = sg_alloc_table(sgt, buf->sgt->nents, GFP_KERNEL);
 	if (ret)
 		goto err_free_sgt;
 
-	if (page_size < PAGE_SIZE)
-		page_size = PAGE_SIZE;
-
-	for_each_sg(sgt->sgl, sgl, nr_pages, i)
-		sg_set_page(sgl, pages[i], page_size, 0);
+	ret = dma_get_sgtable(drm_dev->dev, sgt, buf->kvaddr,
+				buf->dma_addr, buf->size);
+	if (ret < 0) {
+		DRM_ERROR("failed to get sgtable.\n");
+		goto err_free_table;
+	}
 
 	return sgt;
 
+err_free_table:
+	sg_free_table(sgt);
 err_free_sgt:
 	kfree(sgt);
 	sgt = NULL;
@@ -68,32 +70,31 @@ static struct sg_table *
 	struct drm_device *dev = gem_obj->base.dev;
 	struct exynos_drm_gem_buf *buf;
 	struct sg_table *sgt = NULL;
-	unsigned int npages;
 	int nents;
 
 	DRM_DEBUG_PRIME("%s\n", __FILE__);
 
-	mutex_lock(&dev->struct_mutex);
-
 	buf = gem_obj->buffer;
-
-	/* there should always be pages allocated. */
-	if (!buf->pages) {
-		DRM_ERROR("pages is null.\n");
-		goto err_unlock;
+	if (!buf) {
+		DRM_ERROR("buffer is null.\n");
+		return sgt;
 	}
 
-	npages = buf->size / buf->page_size;
+	mutex_lock(&dev->struct_mutex);
 
-	sgt = exynos_pages_to_sg(buf->pages, npages, buf->page_size);
-	if (!sgt) {
-		DRM_DEBUG_PRIME("exynos_pages_to_sg returned NULL!\n");
+	sgt = exynos_get_sgt(dev, buf);
+	if (!sgt)
 		goto err_unlock;
-	}
+
 	nents = dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+	if (!nents) {
+		DRM_ERROR("failed to map sgl with iommu.\n");
+		sgt = NULL;
+		goto err_unlock;
+	}
 
-	DRM_DEBUG_PRIME("npages = %d buffer size = 0x%lx page_size = 0x%lx\n",
-			npages, buf->size, buf->page_size);
+	DRM_DEBUG_PRIME("buffer size = 0x%lx page_size = 0x%lx\n",
+			buf->size, buf->page_size);
 
 err_unlock:
 	mutex_unlock(&dev->struct_mutex);
@@ -105,6 +106,7 @@ static void exynos_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
 						enum dma_data_direction dir)
 {
 	dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
+
 	sg_free_table(sgt);
 	kfree(sgt);
 	sgt = NULL;
@@ -196,7 +198,6 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
 	struct scatterlist *sgl;
 	struct exynos_drm_gem_obj *exynos_gem_obj;
 	struct exynos_drm_gem_buf *buffer;
-	struct page *page;
 	int ret;
 
 	DRM_DEBUG_PRIME("%s\n", __FILE__);
@@ -233,38 +234,27 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
 		goto err_unmap_attach;
 	}
 
-	buffer->pages = kzalloc(sizeof(*page) * sgt->nents, GFP_KERNEL);
-	if (!buffer->pages) {
-		DRM_ERROR("failed to allocate pages.\n");
-		ret = -ENOMEM;
-		goto err_free_buffer;
-	}
-
 	exynos_gem_obj = exynos_drm_gem_init(drm_dev, dma_buf->size);
 	if (!exynos_gem_obj) {
 		ret = -ENOMEM;
-		goto err_free_pages;
+		goto err_free_buffer;
 	}
 
 	sgl = sgt->sgl;
 
-	if (sgt->nents == 1) {
-		buffer->dma_addr = sg_dma_address(sgt->sgl);
-		buffer->size = sg_dma_len(sgt->sgl);
+	buffer->size = dma_buf->size;
+	buffer->dma_addr = sg_dma_address(sgl);
 
+	if (sgt->nents == 1) {
 		/* always physically continuous memory if sgt->nents is 1. */
 		exynos_gem_obj->flags |= EXYNOS_BO_CONTIG;
 	} else {
-		unsigned int i = 0;
-
-		buffer->dma_addr = sg_dma_address(sgl);
-		while (i < sgt->nents) {
-			buffer->pages[i] = sg_page(sgl);
-			buffer->size += sg_dma_len(sgl);
-			sgl = sg_next(sgl);
-			i++;
-		}
-
+		/*
+		 * this case could be CONTIG or NONCONTIG type but for now
+		 * sets NONCONTIG.
+		 * TODO. we have to find a way that exporter can notify
+		 * the type of its own buffer to importer.
+		 */
 		exynos_gem_obj->flags |= EXYNOS_BO_NONCONTIG;
 	}
 
@@ -277,9 +267,6 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
 
 	return &exynos_gem_obj->base;
 
-err_free_pages:
-	kfree(buffer->pages);
-	buffer->pages = NULL;
 err_free_buffer:
 	kfree(buffer);
 	buffer = NULL;

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -40,6 +40,7 @@
 #include "exynos_drm_vidi.h"
 #include "exynos_drm_dmabuf.h"
 #include "exynos_drm_g2d.h"
+#include "exynos_drm_iommu.h"
 
 #define DRIVER_NAME	"exynos"
 #define DRIVER_DESC	"Samsung SoC DRM"
@@ -66,6 +67,18 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
 	INIT_LIST_HEAD(&private->pageflip_event_list);
 	dev->dev_private = (void *)private;
 
+	/*
+	 * 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.
+	 */
+	ret = drm_create_iommu_mapping(dev);
+	if (ret < 0) {
+		DRM_ERROR("failed to create iommu mapping.\n");
+		goto err_crtc;
+	}
+
 	drm_mode_config_init(dev);
 
 	/* init kms poll for handling hpd */
@@ -80,7 +93,7 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
 	for (nr = 0; nr < MAX_CRTC; nr++) {
 		ret = exynos_drm_crtc_create(dev, nr);
 		if (ret)
-			goto err_crtc;
+			goto err_release_iommu_mapping;
 	}
 
 	for (nr = 0; nr < MAX_PLANE; nr++) {
@@ -89,12 +102,12 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
 
 		plane = exynos_plane_init(dev, possible_crtcs, false);
 		if (!plane)
-			goto err_crtc;
+			goto err_release_iommu_mapping;
 	}
 
 	ret = drm_vblank_init(dev, MAX_CRTC);
 	if (ret)
-		goto err_crtc;
+		goto err_release_iommu_mapping;
 
 	/*
 	 * probe sub drivers such as display controller and hdmi driver,
@@ -126,6 +139,8 @@ static int exynos_drm_load(struct drm_device *dev, unsigned long flags)
 	exynos_drm_device_unregister(dev);
 err_vblank:
 	drm_vblank_cleanup(dev);
+err_release_iommu_mapping:
+	drm_release_iommu_mapping(dev);
 err_crtc:
 	drm_mode_config_cleanup(dev);
 	kfree(private);
@@ -142,6 +157,8 @@ static int exynos_drm_unload(struct drm_device *dev)
 	drm_vblank_cleanup(dev);
 	drm_kms_helper_poll_fini(dev);
 	drm_mode_config_cleanup(dev);
+
+	drm_release_iommu_mapping(dev);
 	kfree(dev->dev_private);
 
 	dev->dev_private = NULL;

drivers/gpu/drm/exynos/exynos_drm_drv.h

@@ -241,6 +241,13 @@ struct drm_exynos_file_private {
 
 /*
  * Exynos drm private structure.
+ *
+ * @da_start: start address to device address space.
+ *	with iommu, device address space starts from this address
+ *	otherwise default one.
+ * @da_space_size: size of device address space.
+ *	if 0 then default value is used for it.
+ * @da_space_order: order to device address space.
  */
 struct exynos_drm_private {
 	struct drm_fb_helper *fb_helper;
@@ -255,6 +262,10 @@ struct exynos_drm_private {
 	struct drm_crtc *crtc[MAX_CRTC];
 	struct drm_property *plane_zpos_property;
 	struct drm_property *crtc_mode_property;
+
+	unsigned long da_start;
+	unsigned long da_space_size;
+	unsigned long da_space_order;
 };
 
 /*

drivers/gpu/drm/exynos/exynos_drm_fb.c

@@ -30,10 +30,12 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_helper.h>
+#include <uapi/drm/exynos_drm.h>
 
 #include "exynos_drm_drv.h"
 #include "exynos_drm_fb.h"
 #include "exynos_drm_gem.h"
+#include "exynos_drm_iommu.h"
 
 #define to_exynos_fb(x)	container_of(x, struct exynos_drm_fb, fb)
 
@@ -50,6 +52,32 @@ struct exynos_drm_fb {
 	struct exynos_drm_gem_obj	*exynos_gem_obj[MAX_FB_BUFFER];
 };
 
+static int check_fb_gem_memory_type(struct drm_device *drm_dev,
+				struct exynos_drm_gem_obj *exynos_gem_obj)
+{
+	unsigned int flags;
+
+	/*
+	 * if exynos drm driver supports iommu then framebuffer can use
+	 * all the buffer types.
+	 */
+	if (is_drm_iommu_supported(drm_dev))
+		return 0;
+
+	flags = exynos_gem_obj->flags;
+
+	/*
+	 * without iommu support, not support physically non-continuous memory
+	 * for framebuffer.
+	 */
+	if (IS_NONCONTIG_BUFFER(flags)) {
+		DRM_ERROR("cannot use this gem memory type for fb.\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static void exynos_drm_fb_destroy(struct drm_framebuffer *fb)
 {
 	struct exynos_drm_fb *exynos_fb = to_exynos_fb(fb);
@@ -128,14 +156,25 @@ exynos_drm_framebuffer_init(struct drm_device *dev,
 			    struct drm_gem_object *obj)
 {
 	struct exynos_drm_fb *exynos_fb;
+	struct exynos_drm_gem_obj *exynos_gem_obj;
 	int ret;
 
+	exynos_gem_obj = to_exynos_gem_obj(obj);
+
+	ret = check_fb_gem_memory_type(dev, exynos_gem_obj);
+	if (ret < 0) {
+		DRM_ERROR("cannot use this gem memory type for fb.\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	exynos_fb = kzalloc(sizeof(*exynos_fb), GFP_KERNEL);
 	if (!exynos_fb) {
 		DRM_ERROR("failed to allocate exynos drm framebuffer\n");
 		return ERR_PTR(-ENOMEM);
 	}
 
+	exynos_fb->exynos_gem_obj[0] = exynos_gem_obj;
+
 	ret = drm_framebuffer_init(dev, &exynos_fb->fb, &exynos_drm_fb_funcs);
 	if (ret) {
 		DRM_ERROR("failed to initialize framebuffer\n");
@@ -143,7 +182,6 @@ exynos_drm_framebuffer_init(struct drm_device *dev,
 	}
 
 	drm_helper_mode_fill_fb_struct(&exynos_fb->fb, mode_cmd);
-	exynos_fb->exynos_gem_obj[0] = to_exynos_gem_obj(obj);
 
 	return &exynos_fb->fb;
 }
@@ -214,6 +252,9 @@ exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 	DRM_DEBUG_KMS("buf_cnt = %d\n", exynos_fb->buf_cnt);
 
 	for (i = 1; i < exynos_fb->buf_cnt; i++) {
+		struct exynos_drm_gem_obj *exynos_gem_obj;
+		int ret;
+
 		obj = drm_gem_object_lookup(dev, file_priv,
 				mode_cmd->handles[i]);
 		if (!obj) {
@@ -222,6 +263,15 @@ exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 			return ERR_PTR(-ENOENT);
 		}
 
+		exynos_gem_obj = to_exynos_gem_obj(obj);
+
+		ret = check_fb_gem_memory_type(dev, exynos_gem_obj);
+		if (ret < 0) {
+			DRM_ERROR("cannot use this gem memory type for fb.\n");
+			exynos_drm_fb_destroy(fb);
+			return ERR_PTR(ret);
+		}
+
 		exynos_fb->exynos_gem_obj[i] = to_exynos_gem_obj(obj);
 	}
 

drivers/gpu/drm/exynos/exynos_drm_gem.c

@@ -83,61 +83,12 @@ static void update_vm_cache_attr(struct exynos_drm_gem_obj *obj,
 
 static unsigned long roundup_gem_size(unsigned long size, unsigned int flags)
 {
-	if (!IS_NONCONTIG_BUFFER(flags)) {
-		if (size >= SZ_1M)
-			return roundup(size, SECTION_SIZE);
-		else if (size >= SZ_64K)
-			return roundup(size, SZ_64K);
-		else
-			goto out;
-	}
-out:
-	return roundup(size, PAGE_SIZE);
-}
-
-struct page **exynos_gem_get_pages(struct drm_gem_object *obj,
-						gfp_t gfpmask)
-{
-	struct page *p, **pages;
-	int i, npages;
-
-	npages = obj->size >> PAGE_SHIFT;
-
-	pages = drm_malloc_ab(npages, sizeof(struct page *));
-	if (pages == NULL)
-		return ERR_PTR(-ENOMEM);
-
-	for (i = 0; i < npages; i++) {
-		p = alloc_page(gfpmask);
-		if (IS_ERR(p))
-			goto fail;
-		pages[i] = p;
-	}
-
-	return pages;
-
-fail:
-	while (--i)
-		__free_page(pages[i]);
-
-	drm_free_large(pages);
-	return ERR_CAST(p);
-}
-
-static void exynos_gem_put_pages(struct drm_gem_object *obj,
-					struct page **pages)
-{
-	int npages;
+	/* TODO */
 
-	npages = obj->size >> PAGE_SHIFT;
-
-	while (--npages >= 0)
-		__free_page(pages[npages]);
-
-	drm_free_large(pages);
+	return roundup(size, PAGE_SIZE);
 }
 
-static int exynos_drm_gem_map_pages(struct drm_gem_object *obj,
+static int exynos_drm_gem_map_buf(struct drm_gem_object *obj,
 					struct vm_area_struct *vma,
 					unsigned long f_vaddr,
 					pgoff_t page_offset)
@@ -157,85 +108,6 @@ static int exynos_drm_gem_map_pages(struct drm_gem_object *obj,
 	return vm_insert_mixed(vma, f_vaddr, pfn);
 }
 
-static int exynos_drm_gem_get_pages(struct drm_gem_object *obj)
-{
-	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
-	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
-	struct scatterlist *sgl;
-	struct page **pages;
-	unsigned int npages, i = 0;
-	int ret;
-
-	if (buf->pages) {
-		DRM_DEBUG_KMS("already allocated.\n");
-		return -EINVAL;
-	}
-
-	pages = exynos_gem_get_pages(obj, GFP_HIGHUSER_MOVABLE);
-	if (IS_ERR(pages)) {
-		DRM_ERROR("failed to get pages.\n");
-		return PTR_ERR(pages);
-	}
-
-	npages = obj->size >> PAGE_SHIFT;
-	buf->page_size = PAGE_SIZE;
-
-	buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
-	if (!buf->sgt) {
-		DRM_ERROR("failed to allocate sg table.\n");
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	ret = sg_alloc_table(buf->sgt, npages, GFP_KERNEL);
-	if (ret < 0) {
-		DRM_ERROR("failed to initialize sg table.\n");
-		ret = -EFAULT;
-		goto err1;
-	}
-
-	sgl = buf->sgt->sgl;
-
-	/* set all pages to sg list. */
-	while (i < npages) {
-		sg_set_page(sgl, pages[i], PAGE_SIZE, 0);
-		sg_dma_address(sgl) = page_to_phys(pages[i]);
-		i++;
-		sgl = sg_next(sgl);
-	}
-
-	/* add some codes for UNCACHED type here. TODO */
-
-	buf->pages = pages;
-	return ret;
-err1:
-	kfree(buf->sgt);
-	buf->sgt = NULL;
-err:
-	exynos_gem_put_pages(obj, pages);
-	return ret;
-
-}
-
-static void exynos_drm_gem_put_pages(struct drm_gem_object *obj)
-{
-	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
-	struct exynos_drm_gem_buf *buf = exynos_gem_obj->buffer;
-
-	/*
-	 * if buffer typs is EXYNOS_BO_NONCONTIG then release all pages
-	 * allocated at gem fault handler.
-	 */
-	sg_free_table(buf->sgt);
-	kfree(buf->sgt);
-	buf->sgt = NULL;
-
-	exynos_gem_put_pages(obj, buf->pages);
-	buf->pages = NULL;
-
-	/* add some codes for UNCACHED type here. TODO */
-}
-
 static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
 					struct drm_file *file_priv,
 					unsigned int *handle)
@@ -270,9 +142,6 @@ void exynos_drm_gem_destroy(struct exynos_drm_gem_obj *exynos_gem_obj)
 
 	DRM_DEBUG_KMS("handle count = %d\n", atomic_read(&obj->handle_count));
 
-	if (!buf->pages)
-		return;
-
 	/*
 	 * do not release memory region from exporter.
 	 *
@@ -282,10 +151,7 @@ void exynos_drm_gem_destroy(struct exynos_drm_gem_obj *exynos_gem_obj)
 	if (obj->import_attach)
 		goto out;
 
-	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG)
-		exynos_drm_gem_put_pages(obj);
-	else
-		exynos_drm_free_buf(obj->dev, exynos_gem_obj->flags, buf);
+	exynos_drm_free_buf(obj->dev, exynos_gem_obj->flags, buf);
 
 out:
 	exynos_drm_fini_buf(obj->dev, buf);
@@ -364,22 +230,10 @@ struct exynos_drm_gem_obj *exynos_drm_gem_create(struct drm_device *dev,
 	/* set memory type and cache attribute from user side. */
 	exynos_gem_obj->flags = flags;
 
-	/*
-	 * allocate all pages as desired size if user wants to allocate
-	 * physically non-continuous memory.
-	 */
-	if (flags & EXYNOS_BO_NONCONTIG) {
-		ret = exynos_drm_gem_get_pages(&exynos_gem_obj->base);
-		if (ret < 0) {
-			drm_gem_object_release(&exynos_gem_obj->base);
-			goto err_fini_buf;
-		}
-	} else {
-		ret = exynos_drm_alloc_buf(dev, buf, flags);
-		if (ret < 0) {
-			drm_gem_object_release(&exynos_gem_obj->base);
-			goto err_fini_buf;
-		}
+	ret = exynos_drm_alloc_buf(dev, buf, flags);
+	if (ret < 0) {
+		drm_gem_object_release(&exynos_gem_obj->base);
+		goto err_fini_buf;
 	}
 
 	return exynos_gem_obj;
@@ -495,8 +349,7 @@ static int exynos_drm_gem_mmap_buffer(struct file *filp,
 	struct drm_gem_object *obj = filp->private_data;
 	struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
 	struct exynos_drm_gem_buf *buffer;
-	unsigned long pfn, vm_size, usize, uaddr = vma->vm_start;
-	int ret;
+	unsigned long vm_size;
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
@@ -504,7 +357,7 @@ static int exynos_drm_gem_mmap_buffer(struct file *filp,
 
 	update_vm_cache_attr(exynos_gem_obj, vma);
 
-	vm_size = usize = vma->vm_end - vma->vm_start;
+	vm_size = vma->vm_end - vma->vm_start;
 
 	/*
 	 * a buffer contains information to physically continuous memory
@@ -516,42 +369,9 @@ static int exynos_drm_gem_mmap_buffer(struct file *filp,
 	if (vm_size > buffer->size)
 		return -EINVAL;
 
-	if (exynos_gem_obj->flags & EXYNOS_BO_NONCONTIG) {
-		int i = 0;
-
-		if (!buffer->pages)
-			return -EINVAL;
-
-		vma->vm_flags |= VM_MIXEDMAP;
-
-		do {
-			ret = vm_insert_page(vma, uaddr, buffer->pages[i++]);
-			if (ret) {
-				DRM_ERROR("failed to remap user space.\n");
-				return ret;
-			}
-
-			uaddr += PAGE_SIZE;
-			usize -= PAGE_SIZE;
-		} while (usize > 0);
-	} else {
-		/*
-		 * get page frame number to physical memory to be mapped
-		 * to user space.
-		 */
-		pfn = ((unsigned long)exynos_gem_obj->buffer->dma_addr) >>
-								PAGE_SHIFT;
-
-		DRM_DEBUG_KMS("pfn = 0x%lx\n", pfn);
-
-		if (remap_pfn_range(vma, vma->vm_start, pfn, vm_size,
-					vma->vm_page_prot)) {
-			DRM_ERROR("failed to remap pfn range.\n");
-			return -EAGAIN;
-		}
-	}
-
-	return 0;
+	return dma_mmap_attrs(obj->dev->dev, vma, buffer->kvaddr,
+				buffer->dma_addr, buffer->size,
+				&buffer->dma_attrs);
 }
 
 static const struct file_operations exynos_drm_gem_fops = {
@@ -753,9 +573,9 @@ int exynos_drm_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 
 	mutex_lock(&dev->struct_mutex);
 
-	ret = exynos_drm_gem_map_pages(obj, vma, f_vaddr, page_offset);
+	ret = exynos_drm_gem_map_buf(obj, vma, f_vaddr, page_offset);
 	if (ret < 0)
-		DRM_ERROR("failed to map pages.\n");
+		DRM_ERROR("failed to map a buffer with user.\n");
 
 	mutex_unlock(&dev->struct_mutex);
 

drivers/gpu/drm/exynos/exynos_drm_gem.h

@@ -46,6 +46,7 @@
 struct exynos_drm_gem_buf {
 	void __iomem		*kvaddr;
 	dma_addr_t		dma_addr;
+	struct dma_attrs	dma_attrs;
 	struct sg_table		*sgt;
 	struct page		**pages;
 	unsigned long		page_size;

drivers/gpu/drm/exynos/exynos_drm_iommu.c

+/* exynos_drm_iommu.c
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * Author: Inki Dae <inki.dae@samsung.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <drmP.h>
+#include <drm/exynos_drm.h>
+
+#include <linux/dma-mapping.h>
+#include <linux/iommu.h>
+#include <linux/kref.h>
+
+#include <asm/dma-iommu.h>
+
+#include "exynos_drm_drv.h"
+#include "exynos_drm_iommu.h"
+
+/*
+ * drm_create_iommu_mapping - create a mapping structure
+ *
+ * @drm_dev: DRM device
+ */
+int drm_create_iommu_mapping(struct drm_device *drm_dev)
+{
+	struct dma_iommu_mapping *mapping = NULL;
+	struct exynos_drm_private *priv = drm_dev->dev_private;
+	struct device *dev = drm_dev->dev;
+
+	if (!priv->da_start)
+		priv->da_start = EXYNOS_DEV_ADDR_START;
+	if (!priv->da_space_size)
+		priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
+	if (!priv->da_space_order)
+		priv->da_space_order = EXYNOS_DEV_ADDR_ORDER;
+
+	mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
+						priv->da_space_size,
+						priv->da_space_order);
+	if (!mapping)
+		return -ENOMEM;
+
+	dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
+					GFP_KERNEL);
+	dma_set_max_seg_size(dev, 0xffffffffu);
+	dev->archdata.mapping = mapping;
+
+	return 0;
+}
+
+/*
+ * drm_release_iommu_mapping - release iommu mapping structure
+ *
+ * @drm_dev: DRM device
+ *
+ * if mapping->kref becomes 0 then all things related to iommu mapping
+ * will be released
+ */
+void drm_release_iommu_mapping(struct drm_device *drm_dev)
+{
+	struct device *dev = drm_dev->dev;
+
+	arm_iommu_release_mapping(dev->archdata.mapping);
+}
+
+/*
+ * drm_iommu_attach_device- attach device to iommu mapping
+ *
+ * @drm_dev: DRM device
+ * @subdrv_dev: device to be attach
+ *
+ * This function should be called by sub drivers to attach it to iommu
+ * mapping.
+ */
+int drm_iommu_attach_device(struct drm_device *drm_dev,
+				struct device *subdrv_dev)
+{
+	struct device *dev = drm_dev->dev;
+	int ret;
+
+	if (!dev->archdata.mapping) {
+		DRM_ERROR("iommu_mapping is null.\n");
+		return -EFAULT;
+	}
+
+	subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
+					sizeof(*subdrv_dev->dma_parms),
+					GFP_KERNEL);
+	dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
+
+	ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
+	if (ret < 0) {
+		DRM_DEBUG_KMS("failed iommu attach.\n");
+		return ret;
+	}
+
+	/*
+	 * Set dma_ops to drm_device just one time.
+	 *
+	 * The dma mapping api needs device object and the api is used
+	 * to allocate physial memory and map it with iommu table.
+	 * If iommu attach succeeded, the sub driver would have dma_ops
+	 * for iommu and also all sub drivers have same dma_ops.
+	 */
+	if (!dev->archdata.dma_ops)
+		dev->archdata.dma_ops = subdrv_dev->archdata.dma_ops;
+
+	return 0;
+}
+
+/*
+ * drm_iommu_detach_device -detach device address space mapping from device
+ *
+ * @drm_dev: DRM device
+ * @subdrv_dev: device to be detached
+ *
+ * This function should be called by sub drivers to detach it from iommu
+ * mapping
+ */
+void drm_iommu_detach_device(struct drm_device *drm_dev,
+				struct device *subdrv_dev)
+{
+	struct device *dev = drm_dev->dev;
+	struct dma_iommu_mapping *mapping = dev->archdata.mapping;
+
+	if (!mapping || !mapping->domain)
+		return;
+
+	iommu_detach_device(mapping->domain, subdrv_dev);
+	drm_release_iommu_mapping(drm_dev);
+}

drivers/gpu/drm/exynos/exynos_drm_iommu.h

+/* exynos_drm_iommu.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * Authoer: Inki Dae <inki.dae@samsung.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _EXYNOS_DRM_IOMMU_H_
+#define _EXYNOS_DRM_IOMMU_H_
+
+#define EXYNOS_DEV_ADDR_START	0x20000000
+#define EXYNOS_DEV_ADDR_SIZE	0x40000000
+#define EXYNOS_DEV_ADDR_ORDER	0x4
+
+#ifdef CONFIG_DRM_EXYNOS_IOMMU
+
+int drm_create_iommu_mapping(struct drm_device *drm_dev);
+
+void drm_release_iommu_mapping(struct drm_device *drm_dev);
+
+int drm_iommu_attach_device(struct drm_device *drm_dev,
+				struct device *subdrv_dev);
+
+void drm_iommu_detach_device(struct drm_device *dev_dev,
+				struct device *subdrv_dev);
+
+static inline bool is_drm_iommu_supported(struct drm_device *drm_dev)
+{
+#ifdef CONFIG_ARM_DMA_USE_IOMMU
+	struct device *dev = drm_dev->dev;
+
+	return dev->archdata.mapping ? true : false;
+#else
+	return false;
+#endif
+}
+
+#else
+
+struct dma_iommu_mapping;
+static inline int drm_create_iommu_mapping(struct drm_device *drm_dev)
+{
+	return 0;
+}
+
+static inline void drm_release_iommu_mapping(struct drm_device *drm_dev)
+{
+}
+
+static inline int drm_iommu_attach_device(struct drm_device *drm_dev,
+						struct device *subdrv_dev)
+{
+	return 0;
+}
+
+static inline void drm_iommu_detach_device(struct drm_device *drm_dev,
+						struct device *subdrv_dev)
+{
+}
+
+static inline bool is_drm_iommu_supported(struct drm_device *drm_dev)
+{
+	return false;
+}
+
+#endif
+#endif