diff mbox series

[3/3] drm/exynos: gem: Get rid of the internal 'pages' array

Message ID 20200407134256.9129-4-m.szyprowski@samsung.com
State Accepted
Commit 9940d9d93406f41ad4dc69fa2cda1e059a7ca108
Headers show
Series ExynosDRM - rework GEM internals | expand

Commit Message

Marek Szyprowski April 7, 2020, 1:42 p.m. UTC
Internal pages array and scatter-list for them is not really needed for
anything. FBDev emulation can simply rely on the DMA-mapping framework
to create a proper kernel mapping for the buffer, while all other buffer
use cases don't really need that array at all.

Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_fbdev.c |  28 +----
 drivers/gpu/drm/exynos/exynos_drm_gem.c   | 124 +++++++---------------
 drivers/gpu/drm/exynos/exynos_drm_gem.h   |  13 +--
 3 files changed, 42 insertions(+), 123 deletions(-)

Comments

대인기/Tizen Platform Lab(SR)/삼성전자 April 24, 2020, 8:15 a.m. UTC | #1
20. 4. 7. 오후 10:42에 Marek Szyprowski 이(가) 쓴 글:
> Internal pages array and scatter-list for them is not really needed for
> anything. FBDev emulation can simply rely on the DMA-mapping framework
> to create a proper kernel mapping for the buffer, while all other buffer
> use cases don't really need that array at all.

Picked it up.

Thanks,
Inki Dae

> 
> Suggested-by: Christian König <christian.koenig@amd.com>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_fbdev.c |  28 +----
>  drivers/gpu/drm/exynos/exynos_drm_gem.c   | 124 +++++++---------------
>  drivers/gpu/drm/exynos/exynos_drm_gem.h   |  13 +--
>  3 files changed, 42 insertions(+), 123 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> index e6ceaf36fb04..56a2b47e1af7 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
> @@ -76,7 +76,6 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
>  	struct fb_info *fbi;
>  	struct drm_framebuffer *fb = helper->fb;
>  	unsigned int size = fb->width * fb->height * fb->format->cpp[0];
> -	unsigned int nr_pages;
>  	unsigned long offset;
>  
>  	fbi = drm_fb_helper_alloc_fbi(helper);
> @@ -90,16 +89,6 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
>  
>  	drm_fb_helper_fill_info(fbi, helper, sizes);
>  
> -	nr_pages = exynos_gem->size >> PAGE_SHIFT;
> -
> -	exynos_gem->kvaddr = (void __iomem *) vmap(exynos_gem->pages, nr_pages,
> -				VM_MAP, pgprot_writecombine(PAGE_KERNEL));
> -	if (!exynos_gem->kvaddr) {
> -		DRM_DEV_ERROR(to_dma_dev(helper->dev),
> -			      "failed to map pages to kernel space.\n");
> -		return -EIO;
> -	}
> -
>  	offset = fbi->var.xoffset * fb->format->cpp[0];
>  	offset += fbi->var.yoffset * fb->pitches[0];
>  
> @@ -133,18 +122,7 @@ static int exynos_drm_fbdev_create(struct drm_fb_helper *helper,
>  
>  	size = mode_cmd.pitches[0] * mode_cmd.height;
>  
> -	exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_CONTIG, size);
> -	/*
> -	 * If physically contiguous memory allocation fails and if IOMMU is
> -	 * supported then try to get buffer from non physically contiguous
> -	 * memory area.
> -	 */
> -	if (IS_ERR(exynos_gem) && is_drm_iommu_supported(dev)) {
> -		dev_warn(dev->dev, "contiguous FB allocation failed, falling back to non-contiguous\n");
> -		exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_NONCONTIG,
> -						   size);
> -	}
> -
> +	exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_WC, size, true);
>  	if (IS_ERR(exynos_gem))
>  		return PTR_ERR(exynos_gem);
>  
> @@ -229,12 +207,8 @@ int exynos_drm_fbdev_init(struct drm_device *dev)
>  static void exynos_drm_fbdev_destroy(struct drm_device *dev,
>  				      struct drm_fb_helper *fb_helper)
>  {
> -	struct exynos_drm_fbdev *exynos_fbd = to_exynos_fbdev(fb_helper);
> -	struct exynos_drm_gem *exynos_gem = exynos_fbd->exynos_gem;
>  	struct drm_framebuffer *fb;
>  
> -	vunmap(exynos_gem->kvaddr);
> -
>  	/* release drm framebuffer and real buffer */
>  	if (fb_helper->fb && fb_helper->fb->funcs) {
>  		fb = fb_helper->fb;
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> index 9d4e4d321bda..3c2732380517 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
> @@ -17,28 +17,23 @@
>  #include "exynos_drm_drv.h"
>  #include "exynos_drm_gem.h"
>  
> -static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem)
> +static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem, bool kvmap)
>  {
>  	struct drm_device *dev = exynos_gem->base.dev;
> -	unsigned long attr;
> -	unsigned int nr_pages;
> -	struct sg_table sgt;
> -	int ret = -ENOMEM;
> +	unsigned long attr = 0;
>  
>  	if (exynos_gem->dma_addr) {
>  		DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "already allocated.\n");
>  		return 0;
>  	}
>  
> -	exynos_gem->dma_attrs = 0;
> -
>  	/*
>  	 * if EXYNOS_BO_CONTIG, fully physically contiguous memory
>  	 * region will be allocated else physically contiguous
>  	 * as possible.
>  	 */
>  	if (!(exynos_gem->flags & EXYNOS_BO_NONCONTIG))
> -		exynos_gem->dma_attrs |= DMA_ATTR_FORCE_CONTIGUOUS;
> +		attr |= DMA_ATTR_FORCE_CONTIGUOUS;
>  
>  	/*
>  	 * if EXYNOS_BO_WC or EXYNOS_BO_NONCACHABLE, writecombine mapping
> @@ -46,61 +41,29 @@ static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem)
>  	 */
>  	if (exynos_gem->flags & EXYNOS_BO_WC ||
>  			!(exynos_gem->flags & EXYNOS_BO_CACHABLE))
> -		attr = DMA_ATTR_WRITE_COMBINE;
> +		attr |= DMA_ATTR_WRITE_COMBINE;
>  	else
> -		attr = DMA_ATTR_NON_CONSISTENT;
> -
> -	exynos_gem->dma_attrs |= attr;
> -	exynos_gem->dma_attrs |= DMA_ATTR_NO_KERNEL_MAPPING;
> -
> -	nr_pages = exynos_gem->size >> PAGE_SHIFT;
> +		attr |= DMA_ATTR_NON_CONSISTENT;
>  
> -	exynos_gem->pages = kvmalloc_array(nr_pages, sizeof(struct page *),
> -			GFP_KERNEL | __GFP_ZERO);
> -	if (!exynos_gem->pages) {
> -		DRM_DEV_ERROR(to_dma_dev(dev), "failed to allocate pages.\n");
> -		return -ENOMEM;
> -	}
> +	/* FBDev emulation requires kernel mapping */
> +	if (!kvmap)
> +		attr |= DMA_ATTR_NO_KERNEL_MAPPING;
>  
> +	exynos_gem->dma_attrs = attr;
>  	exynos_gem->cookie = dma_alloc_attrs(to_dma_dev(dev), exynos_gem->size,
>  					     &exynos_gem->dma_addr, GFP_KERNEL,
>  					     exynos_gem->dma_attrs);
>  	if (!exynos_gem->cookie) {
>  		DRM_DEV_ERROR(to_dma_dev(dev), "failed to allocate buffer.\n");
> -		goto err_free;
> -	}
> -
> -	ret = dma_get_sgtable_attrs(to_dma_dev(dev), &sgt, exynos_gem->cookie,
> -				    exynos_gem->dma_addr, exynos_gem->size,
> -				    exynos_gem->dma_attrs);
> -	if (ret < 0) {
> -		DRM_DEV_ERROR(to_dma_dev(dev), "failed to get sgtable.\n");
> -		goto err_dma_free;
> -	}
> -
> -	if (drm_prime_sg_to_page_addr_arrays(&sgt, exynos_gem->pages, NULL,
> -					     nr_pages)) {
> -		DRM_DEV_ERROR(to_dma_dev(dev), "invalid sgtable.\n");
> -		ret = -EINVAL;
> -		goto err_sgt_free;
> +		return -ENOMEM;
>  	}
>  
> -	sg_free_table(&sgt);
> +	if (kvmap)
> +		exynos_gem->kvaddr = exynos_gem->cookie;
>  
>  	DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "dma_addr(0x%lx), size(0x%lx)\n",
>  			(unsigned long)exynos_gem->dma_addr, exynos_gem->size);
> -
>  	return 0;
> -
> -err_sgt_free:
> -	sg_free_table(&sgt);
> -err_dma_free:
> -	dma_free_attrs(to_dma_dev(dev), exynos_gem->size, exynos_gem->cookie,
> -		       exynos_gem->dma_addr, exynos_gem->dma_attrs);
> -err_free:
> -	kvfree(exynos_gem->pages);
> -
> -	return ret;
>  }
>  
>  static void exynos_drm_free_buf(struct exynos_drm_gem *exynos_gem)
> @@ -118,8 +81,6 @@ static void exynos_drm_free_buf(struct exynos_drm_gem *exynos_gem)
>  	dma_free_attrs(to_dma_dev(dev), exynos_gem->size, exynos_gem->cookie,
>  			(dma_addr_t)exynos_gem->dma_addr,
>  			exynos_gem->dma_attrs);
> -
> -	kvfree(exynos_gem->pages);
>  }
>  
>  static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
> @@ -203,7 +164,8 @@ static struct exynos_drm_gem *exynos_drm_gem_init(struct drm_device *dev,
>  
>  struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
>  					     unsigned int flags,
> -					     unsigned long size)
> +					     unsigned long size,
> +					     bool kvmap)
>  {
>  	struct exynos_drm_gem *exynos_gem;
>  	int ret;
> @@ -237,7 +199,7 @@ struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
>  	/* set memory type and cache attribute from user side. */
>  	exynos_gem->flags = flags;
>  
> -	ret = exynos_drm_alloc_buf(exynos_gem);
> +	ret = exynos_drm_alloc_buf(exynos_gem, kvmap);
>  	if (ret < 0) {
>  		drm_gem_object_release(&exynos_gem->base);
>  		kfree(exynos_gem);
> @@ -254,7 +216,7 @@ int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
>  	struct exynos_drm_gem *exynos_gem;
>  	int ret;
>  
> -	exynos_gem = exynos_drm_gem_create(dev, args->flags, args->size);
> +	exynos_gem = exynos_drm_gem_create(dev, args->flags, args->size, false);
>  	if (IS_ERR(exynos_gem))
>  		return PTR_ERR(exynos_gem);
>  
> @@ -365,7 +327,7 @@ int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
>  	else
>  		flags = EXYNOS_BO_CONTIG | EXYNOS_BO_WC;
>  
> -	exynos_gem = exynos_drm_gem_create(dev, flags, args->size);
> +	exynos_gem = exynos_drm_gem_create(dev, flags, args->size, false);
>  	if (IS_ERR(exynos_gem)) {
>  		dev_warn(dev->dev, "FB allocation failed.\n");
>  		return PTR_ERR(exynos_gem);
> @@ -442,11 +404,24 @@ struct drm_gem_object *exynos_drm_gem_prime_import(struct drm_device *dev,
>  struct sg_table *exynos_drm_gem_prime_get_sg_table(struct drm_gem_object *obj)
>  {
>  	struct exynos_drm_gem *exynos_gem = to_exynos_gem(obj);
> -	int npages;
> +	struct drm_device *drm_dev = obj->dev;
> +	struct sg_table *sgt;
> +	int ret;
> +
> +	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
> +	if (!sgt)
> +		return ERR_PTR(-ENOMEM);
>  
> -	npages = exynos_gem->size >> PAGE_SHIFT;
> +	ret = dma_get_sgtable_attrs(to_dma_dev(drm_dev), sgt, exynos_gem->cookie,
> +				    exynos_gem->dma_addr, exynos_gem->size,
> +				    exynos_gem->dma_attrs);
> +	if (ret) {
> +		DRM_ERROR("failed to get sgtable, %d\n", ret);
> +		kfree(sgt);
> +		return ERR_PTR(ret);
> +	}
>  
> -	return drm_prime_pages_to_sg(exynos_gem->pages, npages);
> +	return sgt;
>  }
>  
>  struct drm_gem_object *
> @@ -455,8 +430,6 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>  				     struct sg_table *sgt)
>  {
>  	struct exynos_drm_gem *exynos_gem;
> -	int npages;
> -	int ret;
>  
>  	if (sgt->nents != 1) {
>  		dma_addr_t next_addr = sg_dma_address(sgt->sgl);
> @@ -476,26 +449,8 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>  	}
>  
>  	exynos_gem = exynos_drm_gem_init(dev, attach->dmabuf->size);
> -	if (IS_ERR(exynos_gem)) {
> -		ret = PTR_ERR(exynos_gem);
> -		return ERR_PTR(ret);
> -	}
> -
> -	exynos_gem->dma_addr = sg_dma_address(sgt->sgl);
> -
> -	npages = exynos_gem->size >> PAGE_SHIFT;
> -	exynos_gem->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
> -	if (!exynos_gem->pages) {
> -		ret = -ENOMEM;
> -		goto err;
> -	}
> -
> -	ret = drm_prime_sg_to_page_addr_arrays(sgt, exynos_gem->pages, NULL,
> -					       npages);
> -	if (ret < 0)
> -		goto err_free_large;
> -
> -	exynos_gem->sgt = sgt;
> +	if (IS_ERR(exynos_gem))
> +		return ERR_CAST(exynos_gem);
>  
>  	/*
>  	 * Buffer has been mapped as contiguous into DMA address space,
> @@ -507,14 +462,9 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
>  	else
>  		exynos_gem->flags |= EXYNOS_BO_CONTIG;
>  
> +	exynos_gem->dma_addr = sg_dma_address(sgt->sgl);
> +	exynos_gem->sgt = sgt;
>  	return &exynos_gem->base;
> -
> -err_free_large:
> -	kvfree(exynos_gem->pages);
> -err:
> -	drm_gem_object_release(&exynos_gem->base);
> -	kfree(exynos_gem);
> -	return ERR_PTR(ret);
>  }
>  
>  void *exynos_drm_gem_prime_vmap(struct drm_gem_object *obj)
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> index f00044c0b688..6ef001f890aa 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
> @@ -21,20 +21,15 @@
>   * @base: a gem object.
>   *	- a new handle to this gem object would be created
>   *	by drm_gem_handle_create().
> - * @buffer: a pointer to exynos_drm_gem_buffer object.
> - *	- contain the information to memory region allocated
> - *	by user request or at framebuffer creation.
> - *	continuous memory region allocated by user request
> - *	or at framebuffer creation.
>   * @flags: indicate memory type to allocated buffer and cache attruibute.
>   * @size: size requested from user, in bytes and this size is aligned
>   *	in page unit.
>   * @cookie: cookie returned by dma_alloc_attrs
> - * @kvaddr: kernel virtual address to allocated memory region.
> + * @kvaddr: kernel virtual address to allocated memory region (for fbdev)
>   * @dma_addr: bus address(accessed by dma) to allocated memory region.
>   *	- this address could be physical address without IOMMU and
>   *	device address with IOMMU.
> - * @pages: Array of backing pages.
> + * @dma_attrs: attrs passed dma mapping framework
>   * @sgt: Imported sg_table.
>   *
>   * P.S. this object would be transferred to user as kms_bo.handle so
> @@ -48,7 +43,6 @@ struct exynos_drm_gem {
>  	void __iomem		*kvaddr;
>  	dma_addr_t		dma_addr;
>  	unsigned long		dma_attrs;
> -	struct page		**pages;
>  	struct sg_table		*sgt;
>  };
>  
> @@ -58,7 +52,8 @@ void exynos_drm_gem_destroy(struct exynos_drm_gem *exynos_gem);
>  /* create a new buffer with gem object */
>  struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
>  					     unsigned int flags,
> -					     unsigned long size);
> +					     unsigned long size,
> +					     bool kvmap);
>  
>  /*
>   * request gem object creation and buffer allocation as the size
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index e6ceaf36fb04..56a2b47e1af7 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -76,7 +76,6 @@  static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 	struct fb_info *fbi;
 	struct drm_framebuffer *fb = helper->fb;
 	unsigned int size = fb->width * fb->height * fb->format->cpp[0];
-	unsigned int nr_pages;
 	unsigned long offset;
 
 	fbi = drm_fb_helper_alloc_fbi(helper);
@@ -90,16 +89,6 @@  static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 
 	drm_fb_helper_fill_info(fbi, helper, sizes);
 
-	nr_pages = exynos_gem->size >> PAGE_SHIFT;
-
-	exynos_gem->kvaddr = (void __iomem *) vmap(exynos_gem->pages, nr_pages,
-				VM_MAP, pgprot_writecombine(PAGE_KERNEL));
-	if (!exynos_gem->kvaddr) {
-		DRM_DEV_ERROR(to_dma_dev(helper->dev),
-			      "failed to map pages to kernel space.\n");
-		return -EIO;
-	}
-
 	offset = fbi->var.xoffset * fb->format->cpp[0];
 	offset += fbi->var.yoffset * fb->pitches[0];
 
@@ -133,18 +122,7 @@  static int exynos_drm_fbdev_create(struct drm_fb_helper *helper,
 
 	size = mode_cmd.pitches[0] * mode_cmd.height;
 
-	exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_CONTIG, size);
-	/*
-	 * If physically contiguous memory allocation fails and if IOMMU is
-	 * supported then try to get buffer from non physically contiguous
-	 * memory area.
-	 */
-	if (IS_ERR(exynos_gem) && is_drm_iommu_supported(dev)) {
-		dev_warn(dev->dev, "contiguous FB allocation failed, falling back to non-contiguous\n");
-		exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_NONCONTIG,
-						   size);
-	}
-
+	exynos_gem = exynos_drm_gem_create(dev, EXYNOS_BO_WC, size, true);
 	if (IS_ERR(exynos_gem))
 		return PTR_ERR(exynos_gem);
 
@@ -229,12 +207,8 @@  int exynos_drm_fbdev_init(struct drm_device *dev)
 static void exynos_drm_fbdev_destroy(struct drm_device *dev,
 				      struct drm_fb_helper *fb_helper)
 {
-	struct exynos_drm_fbdev *exynos_fbd = to_exynos_fbdev(fb_helper);
-	struct exynos_drm_gem *exynos_gem = exynos_fbd->exynos_gem;
 	struct drm_framebuffer *fb;
 
-	vunmap(exynos_gem->kvaddr);
-
 	/* release drm framebuffer and real buffer */
 	if (fb_helper->fb && fb_helper->fb->funcs) {
 		fb = fb_helper->fb;
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 9d4e4d321bda..3c2732380517 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -17,28 +17,23 @@ 
 #include "exynos_drm_drv.h"
 #include "exynos_drm_gem.h"
 
-static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem)
+static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem, bool kvmap)
 {
 	struct drm_device *dev = exynos_gem->base.dev;
-	unsigned long attr;
-	unsigned int nr_pages;
-	struct sg_table sgt;
-	int ret = -ENOMEM;
+	unsigned long attr = 0;
 
 	if (exynos_gem->dma_addr) {
 		DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "already allocated.\n");
 		return 0;
 	}
 
-	exynos_gem->dma_attrs = 0;
-
 	/*
 	 * if EXYNOS_BO_CONTIG, fully physically contiguous memory
 	 * region will be allocated else physically contiguous
 	 * as possible.
 	 */
 	if (!(exynos_gem->flags & EXYNOS_BO_NONCONTIG))
-		exynos_gem->dma_attrs |= DMA_ATTR_FORCE_CONTIGUOUS;
+		attr |= DMA_ATTR_FORCE_CONTIGUOUS;
 
 	/*
 	 * if EXYNOS_BO_WC or EXYNOS_BO_NONCACHABLE, writecombine mapping
@@ -46,61 +41,29 @@  static int exynos_drm_alloc_buf(struct exynos_drm_gem *exynos_gem)
 	 */
 	if (exynos_gem->flags & EXYNOS_BO_WC ||
 			!(exynos_gem->flags & EXYNOS_BO_CACHABLE))
-		attr = DMA_ATTR_WRITE_COMBINE;
+		attr |= DMA_ATTR_WRITE_COMBINE;
 	else
-		attr = DMA_ATTR_NON_CONSISTENT;
-
-	exynos_gem->dma_attrs |= attr;
-	exynos_gem->dma_attrs |= DMA_ATTR_NO_KERNEL_MAPPING;
-
-	nr_pages = exynos_gem->size >> PAGE_SHIFT;
+		attr |= DMA_ATTR_NON_CONSISTENT;
 
-	exynos_gem->pages = kvmalloc_array(nr_pages, sizeof(struct page *),
-			GFP_KERNEL | __GFP_ZERO);
-	if (!exynos_gem->pages) {
-		DRM_DEV_ERROR(to_dma_dev(dev), "failed to allocate pages.\n");
-		return -ENOMEM;
-	}
+	/* FBDev emulation requires kernel mapping */
+	if (!kvmap)
+		attr |= DMA_ATTR_NO_KERNEL_MAPPING;
 
+	exynos_gem->dma_attrs = attr;
 	exynos_gem->cookie = dma_alloc_attrs(to_dma_dev(dev), exynos_gem->size,
 					     &exynos_gem->dma_addr, GFP_KERNEL,
 					     exynos_gem->dma_attrs);
 	if (!exynos_gem->cookie) {
 		DRM_DEV_ERROR(to_dma_dev(dev), "failed to allocate buffer.\n");
-		goto err_free;
-	}
-
-	ret = dma_get_sgtable_attrs(to_dma_dev(dev), &sgt, exynos_gem->cookie,
-				    exynos_gem->dma_addr, exynos_gem->size,
-				    exynos_gem->dma_attrs);
-	if (ret < 0) {
-		DRM_DEV_ERROR(to_dma_dev(dev), "failed to get sgtable.\n");
-		goto err_dma_free;
-	}
-
-	if (drm_prime_sg_to_page_addr_arrays(&sgt, exynos_gem->pages, NULL,
-					     nr_pages)) {
-		DRM_DEV_ERROR(to_dma_dev(dev), "invalid sgtable.\n");
-		ret = -EINVAL;
-		goto err_sgt_free;
+		return -ENOMEM;
 	}
 
-	sg_free_table(&sgt);
+	if (kvmap)
+		exynos_gem->kvaddr = exynos_gem->cookie;
 
 	DRM_DEV_DEBUG_KMS(to_dma_dev(dev), "dma_addr(0x%lx), size(0x%lx)\n",
 			(unsigned long)exynos_gem->dma_addr, exynos_gem->size);
-
 	return 0;
-
-err_sgt_free:
-	sg_free_table(&sgt);
-err_dma_free:
-	dma_free_attrs(to_dma_dev(dev), exynos_gem->size, exynos_gem->cookie,
-		       exynos_gem->dma_addr, exynos_gem->dma_attrs);
-err_free:
-	kvfree(exynos_gem->pages);
-
-	return ret;
 }
 
 static void exynos_drm_free_buf(struct exynos_drm_gem *exynos_gem)
@@ -118,8 +81,6 @@  static void exynos_drm_free_buf(struct exynos_drm_gem *exynos_gem)
 	dma_free_attrs(to_dma_dev(dev), exynos_gem->size, exynos_gem->cookie,
 			(dma_addr_t)exynos_gem->dma_addr,
 			exynos_gem->dma_attrs);
-
-	kvfree(exynos_gem->pages);
 }
 
 static int exynos_drm_gem_handle_create(struct drm_gem_object *obj,
@@ -203,7 +164,8 @@  static struct exynos_drm_gem *exynos_drm_gem_init(struct drm_device *dev,
 
 struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
 					     unsigned int flags,
-					     unsigned long size)
+					     unsigned long size,
+					     bool kvmap)
 {
 	struct exynos_drm_gem *exynos_gem;
 	int ret;
@@ -237,7 +199,7 @@  struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
 	/* set memory type and cache attribute from user side. */
 	exynos_gem->flags = flags;
 
-	ret = exynos_drm_alloc_buf(exynos_gem);
+	ret = exynos_drm_alloc_buf(exynos_gem, kvmap);
 	if (ret < 0) {
 		drm_gem_object_release(&exynos_gem->base);
 		kfree(exynos_gem);
@@ -254,7 +216,7 @@  int exynos_drm_gem_create_ioctl(struct drm_device *dev, void *data,
 	struct exynos_drm_gem *exynos_gem;
 	int ret;
 
-	exynos_gem = exynos_drm_gem_create(dev, args->flags, args->size);
+	exynos_gem = exynos_drm_gem_create(dev, args->flags, args->size, false);
 	if (IS_ERR(exynos_gem))
 		return PTR_ERR(exynos_gem);
 
@@ -365,7 +327,7 @@  int exynos_drm_gem_dumb_create(struct drm_file *file_priv,
 	else
 		flags = EXYNOS_BO_CONTIG | EXYNOS_BO_WC;
 
-	exynos_gem = exynos_drm_gem_create(dev, flags, args->size);
+	exynos_gem = exynos_drm_gem_create(dev, flags, args->size, false);
 	if (IS_ERR(exynos_gem)) {
 		dev_warn(dev->dev, "FB allocation failed.\n");
 		return PTR_ERR(exynos_gem);
@@ -442,11 +404,24 @@  struct drm_gem_object *exynos_drm_gem_prime_import(struct drm_device *dev,
 struct sg_table *exynos_drm_gem_prime_get_sg_table(struct drm_gem_object *obj)
 {
 	struct exynos_drm_gem *exynos_gem = to_exynos_gem(obj);
-	int npages;
+	struct drm_device *drm_dev = obj->dev;
+	struct sg_table *sgt;
+	int ret;
+
+	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+	if (!sgt)
+		return ERR_PTR(-ENOMEM);
 
-	npages = exynos_gem->size >> PAGE_SHIFT;
+	ret = dma_get_sgtable_attrs(to_dma_dev(drm_dev), sgt, exynos_gem->cookie,
+				    exynos_gem->dma_addr, exynos_gem->size,
+				    exynos_gem->dma_attrs);
+	if (ret) {
+		DRM_ERROR("failed to get sgtable, %d\n", ret);
+		kfree(sgt);
+		return ERR_PTR(ret);
+	}
 
-	return drm_prime_pages_to_sg(exynos_gem->pages, npages);
+	return sgt;
 }
 
 struct drm_gem_object *
@@ -455,8 +430,6 @@  exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
 				     struct sg_table *sgt)
 {
 	struct exynos_drm_gem *exynos_gem;
-	int npages;
-	int ret;
 
 	if (sgt->nents != 1) {
 		dma_addr_t next_addr = sg_dma_address(sgt->sgl);
@@ -476,26 +449,8 @@  exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
 	}
 
 	exynos_gem = exynos_drm_gem_init(dev, attach->dmabuf->size);
-	if (IS_ERR(exynos_gem)) {
-		ret = PTR_ERR(exynos_gem);
-		return ERR_PTR(ret);
-	}
-
-	exynos_gem->dma_addr = sg_dma_address(sgt->sgl);
-
-	npages = exynos_gem->size >> PAGE_SHIFT;
-	exynos_gem->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
-	if (!exynos_gem->pages) {
-		ret = -ENOMEM;
-		goto err;
-	}
-
-	ret = drm_prime_sg_to_page_addr_arrays(sgt, exynos_gem->pages, NULL,
-					       npages);
-	if (ret < 0)
-		goto err_free_large;
-
-	exynos_gem->sgt = sgt;
+	if (IS_ERR(exynos_gem))
+		return ERR_CAST(exynos_gem);
 
 	/*
 	 * Buffer has been mapped as contiguous into DMA address space,
@@ -507,14 +462,9 @@  exynos_drm_gem_prime_import_sg_table(struct drm_device *dev,
 	else
 		exynos_gem->flags |= EXYNOS_BO_CONTIG;
 
+	exynos_gem->dma_addr = sg_dma_address(sgt->sgl);
+	exynos_gem->sgt = sgt;
 	return &exynos_gem->base;
-
-err_free_large:
-	kvfree(exynos_gem->pages);
-err:
-	drm_gem_object_release(&exynos_gem->base);
-	kfree(exynos_gem);
-	return ERR_PTR(ret);
 }
 
 void *exynos_drm_gem_prime_vmap(struct drm_gem_object *obj)
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index f00044c0b688..6ef001f890aa 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -21,20 +21,15 @@ 
  * @base: a gem object.
  *	- a new handle to this gem object would be created
  *	by drm_gem_handle_create().
- * @buffer: a pointer to exynos_drm_gem_buffer object.
- *	- contain the information to memory region allocated
- *	by user request or at framebuffer creation.
- *	continuous memory region allocated by user request
- *	or at framebuffer creation.
  * @flags: indicate memory type to allocated buffer and cache attruibute.
  * @size: size requested from user, in bytes and this size is aligned
  *	in page unit.
  * @cookie: cookie returned by dma_alloc_attrs
- * @kvaddr: kernel virtual address to allocated memory region.
+ * @kvaddr: kernel virtual address to allocated memory region (for fbdev)
  * @dma_addr: bus address(accessed by dma) to allocated memory region.
  *	- this address could be physical address without IOMMU and
  *	device address with IOMMU.
- * @pages: Array of backing pages.
+ * @dma_attrs: attrs passed dma mapping framework
  * @sgt: Imported sg_table.
  *
  * P.S. this object would be transferred to user as kms_bo.handle so
@@ -48,7 +43,6 @@  struct exynos_drm_gem {
 	void __iomem		*kvaddr;
 	dma_addr_t		dma_addr;
 	unsigned long		dma_attrs;
-	struct page		**pages;
 	struct sg_table		*sgt;
 };
 
@@ -58,7 +52,8 @@  void exynos_drm_gem_destroy(struct exynos_drm_gem *exynos_gem);
 /* create a new buffer with gem object */
 struct exynos_drm_gem *exynos_drm_gem_create(struct drm_device *dev,
 					     unsigned int flags,
-					     unsigned long size);
+					     unsigned long size,
+					     bool kvmap);
 
 /*
  * request gem object creation and buffer allocation as the size