gpu: host1x: Free the IOMMU domain when there is no device to attach

When there is no device to attach to the IOMMU domain, as may be the
case when the device-tree does not contain the proper iommu node, it is
best to keep going without IOMMU support rather than failing.
This allows the driver to probe and function instead of taking down
all of the tegra drm driver, leading to missing display support.

Signed-off-by: Paul Kocialkowski <contact@paulk.fr>
Fixes: 404bfb78daf3 ("gpu: host1x: Add IOMMU support")
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170710193305.5987-1-contact@paulk.fr

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 2c58a390123a1a7c3f8a4e6fd6f11a34f3340fbe..7782725141648360cedd89f3363155da5f7c8d9c 100644 (file)
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -186,8 +186,13 @@ static int host1x_probe(struct platform_device *pdev)
                        return -ENOMEM;
 
                err = iommu_attach_device(host->domain, &pdev->dev);
-               if (err)
+               if (err == -ENODEV) {
+                       iommu_domain_free(host->domain);
+                       host->domain = NULL;
+                       goto skip_iommu;
+               } else if (err) {
                        goto fail_free_domain;
+               }
 
                geometry = &host->domain->geometry;
 
@@ -198,6 +203,7 @@ static int host1x_probe(struct platform_device *pdev)
                host->iova_end = geometry->aperture_end;
        }
 
+skip_iommu:
        err = host1x_channel_list_init(&host->channel_list,
                                       host->info->nb_channels);
        if (err) {