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Commit a5d7ac30 authored by Carlo Caione's avatar Carlo Caione Committed by Inki Dae
Browse files

drm/exynos: fix DMA_ATTR_NO_KERNEL_MAPPING usage 



The Exynos DRM driver doesn't follow the correct API when dealing with
dma_{alloc, mmap, free}_attrs functions and the
DMA_ATTR_NO_KERNEL_MAPPING attribute.

When a IOMMU is not available and the DMA_ATTR_NO_KERNEL_MAPPING is
used, the driver should use the pointer returned by dma_alloc_attr() as
a cookie.

The Exynos DRM driver directly uses the non-requested virtual kernel
address returned by the DMA mapping subsystem. This just works now
because the non-IOMMU codepath doesn't obey DMA_ATTR_NO_KERNEL_MAPPING
but we need to fix it before fixing the DMA layer.

Signed-off-by: default avatarCarlo Caione <carlo@caione.org>
Acked-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: default avatarInki Dae <inki.dae@samsung.com>
parent 129046c6

drivers/gpu/drm/exynos/exynos_drm_buf.c

+3 −3
Original line number Diff line number Diff line
@@ -63,11 +63,11 @@ static int lowlevel_buffer_allocate(struct drm_device *dev, 
			return -ENOMEM;

		}



		buf->kvaddr = (void __iomem *)dma_alloc_attrs(dev->dev,

		buf->cookie = dma_alloc_attrs(dev->dev,

					buf->size,

					&buf->dma_addr, GFP_KERNEL,

					&buf->dma_attrs);

		if (!buf->kvaddr) {

		if (!buf->cookie) {

			DRM_ERROR("failed to allocate buffer.\n");

			ret = -ENOMEM;

			goto err_free;
@@ -132,7 +132,7 @@ static void lowlevel_buffer_deallocate(struct drm_device *dev, 
	buf->sgt = NULL;



	if (!is_drm_iommu_supported(dev)) {

		dma_free_attrs(dev->dev, buf->size, buf->kvaddr,

		dma_free_attrs(dev->dev, buf->size, buf->cookie,

				(dma_addr_t)buf->dma_addr, &buf->dma_attrs);

		drm_free_large(buf->pages);

	} else

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

+9 −20
Original line number Diff line number Diff line
@@ -79,9 +79,9 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, 
				     struct drm_framebuffer *fb)

{

	struct fb_info *fbi = helper->fbdev;

	struct drm_device *dev = helper->dev;

	struct exynos_drm_gem_buf *buffer;

	unsigned int size = fb->width * fb->height * (fb->bits_per_pixel >> 3);

	unsigned int nr_pages;

	unsigned long offset;



	drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->depth);
@@ -94,26 +94,15 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper, 
		return -EFAULT;

	}



	/* map pages with kernel virtual space. */

	if (!buffer->kvaddr) {

		if (is_drm_iommu_supported(dev)) {

			unsigned int nr_pages = buffer->size >> PAGE_SHIFT;

	nr_pages = buffer->size >> PAGE_SHIFT;



	buffer->kvaddr = (void __iomem *) vmap(buffer->pages,

			nr_pages, VM_MAP,

			pgprot_writecombine(PAGE_KERNEL));

		} else {

			phys_addr_t dma_addr = buffer->dma_addr;

			if (dma_addr)

				buffer->kvaddr = (void __iomem *)phys_to_virt(dma_addr);

			else

				buffer->kvaddr = (void __iomem *)NULL;

		}

	if (!buffer->kvaddr) {

		DRM_ERROR("failed to map pages to kernel space.\n");

		return -EIO;

	}

	}



	/* buffer count to framebuffer always is 1 at booting time. */

	exynos_drm_fb_set_buf_cnt(fb, 1);
@@ -313,7 +302,7 @@ static void exynos_drm_fbdev_destroy(struct drm_device *dev, 
	struct exynos_drm_gem_obj *exynos_gem_obj = exynos_fbd->exynos_gem_obj;

	struct drm_framebuffer *fb;



	if (is_drm_iommu_supported(dev) && exynos_gem_obj->buffer->kvaddr)

	if (exynos_gem_obj->buffer->kvaddr)

		vunmap(exynos_gem_obj->buffer->kvaddr);



	/* release drm framebuffer and real buffer */

drivers/gpu/drm/exynos/exynos_drm_gem.h

+2 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
/*

 * exynos drm gem buffer structure.

 *

 * @cookie: cookie returned by dma_alloc_attrs

 * @kvaddr: kernel virtual address to allocated memory region.

 * *userptr: user space address.

 * @dma_addr: bus address(accessed by dma) to allocated memory region.
@@ -35,6 +36,7 @@ 
 *	VM_PFNMAP or not.

 */

struct exynos_drm_gem_buf {

	void 			*cookie;

	void __iomem		*kvaddr;

	unsigned long		userptr;

	dma_addr_t		dma_addr;