drm/tegra: dc: Inherit DMA mask

Inherit the DMA mask from host1x (on Tegra210 and earlier) or the
display hub (on Tegra186 and later). This is necessary in order to
properly map buffers without SMMU support and use the maximum IOVA
space available with SMMU support.

Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: thierryreding

drivers/gpu/drm/tegra/dc.c

@@ -2538,9 +2538,16 @@ static int tegra_dc_couple(struct tegra_dc *dc)
 
 static int tegra_dc_probe(struct platform_device *pdev)
 {
+	u64 dma_mask = dma_get_mask(pdev->dev.parent);
 	struct tegra_dc *dc;
 	int err;
 
+	err = dma_coerce_mask_and_coherent(&pdev->dev, dma_mask);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", err);
+		return err;
+	}
+
 	dc = devm_kzalloc(&pdev->dev, sizeof(*dc), GFP_KERNEL);
 	if (!dc)
 		return -ENOMEM;

drivers/gpu/drm/tegra/hub.c

@@ -848,12 +848,19 @@ static const struct host1x_client_ops tegra_display_hub_ops = {
 
 static int tegra_display_hub_probe(struct platform_device *pdev)
 {
+	u64 dma_mask = dma_get_mask(pdev->dev.parent);
 	struct device_node *child = NULL;
 	struct tegra_display_hub *hub;
 	struct clk *clk;
 	unsigned int i;
 	int err;
 
+	err = dma_coerce_mask_and_coherent(&pdev->dev, dma_mask);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to set DMA mask: %d\n", err);
+		return err;
+	}
+
 	hub = devm_kzalloc(&pdev->dev, sizeof(*hub), GFP_KERNEL);
 	if (!hub)
 		return -ENOMEM;