[PATCH for-5.3] drm/omap: ensure we have a valid dma_mask

[Christoph Hellwig <hch@lst.de>]

The omapfb platform devices does not have a DMA mask set.  The
traditional arm DMA code ignores, but the generic dma-direct/swiotlb
has stricter checks and thus fails mappings without a DMA mask.
As we use swiotlb for arm with LPAE now, omap needs to catch up
and actually set a DMA mask.

Fixes: ad3c7b18c5b3 ("arm: use swiotlb for bounce buffering on LPAE configs")
Reported-by: "H. Nikolaus Schaller" <hns@goldelico.com>
Tested-by: "H. Nikolaus Schaller" <hns@goldelico.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/gpu/drm/omapdrm/omap_fbdev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/omapdrm/omap_fbdev.c b/drivers/gpu/drm/omapdrm/omap_fbdev.c
index 561c4812545b..2c8abf07e617 100644
--- a/drivers/gpu/drm/omapdrm/omap_fbdev.c
+++ b/drivers/gpu/drm/omapdrm/omap_fbdev.c
@@ -232,6 +232,8 @@ void omap_fbdev_init(struct drm_device *dev)
 	if (!priv->num_pipes)
 		return;
 
+	dma_coerce_mask_and_coherent(dev->dev, DMA_BIT_MASK(32));
+
 	fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
 	if (!fbdev)
 		goto fail;
-- 
2.20.1