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: Carlo Caione <carlo@caione.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.h b/drivers/gpu/drm/exynos/exynos_drm_gem.h
index ec58fe9c40df..308173cb4f0a 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.h
@@ -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;