drm/etnaviv: fix dma configuration of the virtual device

The DMA configuration of the virtual device is inherited from the first
actual etnaviv device. Unfortunately, this doesn't work with an IOMMU:

[    5.191008] Failed to set up IOMMU for device (null); retaining platform DMA ops

This is because there is no associated iommu_group with the device. The
group is set in iommu_group_add_device() which is eventually called by
device_add() via the platform bus:
  device_add()
    blocking_notifier_call_chain()
      iommu_bus_notifier()
        iommu_probe_device()
          __iommu_probe_device()
            iommu_group_get_for_dev()
              iommu_group_add_device()

Move of_dma_configure() into the probe function, which is called after
device_add(). Normally, the platform code will already call it itself
if .of_node is set. Unfortunately, this isn't the case here.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index 2509b3e85709137c7edcc01a70ccb41eed206bba..54eb653ca2954378580a2d604ecae29943a092dc 100644 (file)
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -589,6 +589,7 @@ static int compare_str(struct device *dev, void *data)
 static int etnaviv_pdev_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
+       struct device_node *first_node = NULL;
        struct component_match *match = NULL;
 
        if (!dev->platform_data) {
@@ -598,6 +599,9 @@ static int etnaviv_pdev_probe(struct platform_device *pdev)
                        if (!of_device_is_available(core_node))
                                continue;
 
+                       if (!first_node)
+                               first_node = core_node;
+
                        drm_of_component_match_add(&pdev->dev, &match,
                                                   compare_of, core_node);
                }
@@ -609,6 +613,14 @@ static int etnaviv_pdev_probe(struct platform_device *pdev)
                        component_match_add(dev, &match, compare_str, names[i]);
        }
 
+       /*
+        * Apply the same DMA configuration to the virtual etnaviv
+        * device as the GPU we found. This assumes that all Vivante
+        * GPUs in the system share the same DMA constraints.
+        */
+       if (first_node)
+               of_dma_configure(&pdev->dev, first_node, true);
+
        return component_master_add_with_match(dev, &etnaviv_master_ops, match);
 }
 
@@ -662,13 +674,6 @@ static int __init etnaviv_init(void)
                pdev->dev.coherent_dma_mask = DMA_BIT_MASK(40);
                pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
 
-               /*
-                * Apply the same DMA configuration to the virtual etnaviv
-                * device as the GPU we found. This assumes that all Vivante
-                * GPUs in the system share the same DMA constraints.
-                */
-               of_dma_configure(&pdev->dev, np, true);
-
                ret = platform_device_add(pdev);
                if (ret) {
                        platform_device_put(pdev);