[PATCH v2] drm/exynos: add exynos drm specific fb_mmap function

[Prathyush K]

This patch adds a exynos drm specific implementation of fb_mmap.
The root framebuffer is allocated using dma_alloc_attrs which can
allocate a contig or noncontig buffer depending on whether an iommu
is attached to drm device or not. The default fb_mmap function
always assumes the root fb to be contiguous thus failing in case of
a non-contig buffer.

The exynos drm specific implementation of fb_mmap extracts the private
data from the fb_info and calls dma_mmap_attrs with the parameters
used while allocating the buffer.

Signed-off-by: Prathyush K <prathyush.k at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_fbdev.c |   30 +++++++++++++++++++++++++++++
 1 files changed, 30 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
index 67eb6ba..62314ca 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c
@@ -46,8 +46,38 @@ struct exynos_drm_fbdev {
 	struct exynos_drm_gem_obj	*exynos_gem_obj;
 };
 
+static int exynos_drm_fb_mmap(struct fb_info *info,
+			struct vm_area_struct *vma)
+{
+	struct drm_fb_helper *helper = info->par;
+	struct exynos_drm_fbdev *exynos_fbd = to_exynos_fbdev(helper);
+	struct exynos_drm_gem_obj *exynos_gem_obj = exynos_fbd->exynos_gem_obj;
+	struct exynos_drm_gem_buf *buffer = exynos_gem_obj->buffer;
+	unsigned long vm_size;
+	int ret;
+
+	DRM_DEBUG_KMS("%s\n", __func__);
+
+	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
+
+	vm_size = vma->vm_end - vma->vm_start;
+
+	if (vm_size > buffer->size)
+		return -EINVAL;
+
+	ret = dma_mmap_attrs(helper->dev->dev, vma, buffer->kvaddr,
+		buffer->dma_addr, vm_size, &buffer->dma_attrs);
+	if (ret < 0) {
+		DRM_ERROR("failed to mmap.\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static struct fb_ops exynos_drm_fb_ops = {
 	.owner		= THIS_MODULE,
+	.fb_mmap        = exynos_drm_fb_mmap,
 	.fb_fillrect	= cfb_fillrect,
 	.fb_copyarea	= cfb_copyarea,
 	.fb_imageblit	= cfb_imageblit,
-- 
1.7.0.4