From fea20995976f4b2e8968f852a18e280487d42f0d Mon Sep 17 00:00:00 2001
From: Paul Kocialkowski <contact@paulk.fr>
Date: Mon, 10 Jul 2017 21:33:05 +0200
Subject: [PATCH] gpu: host1x: Free the IOMMU domain when there is no device to attach
Git-commit: fea20995976f4b2e8968f852a18e280487d42f0d
Patch-mainline: v4.13-rc3
References: bsc#1051510

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
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/host1x/dev.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -186,8 +186,13 @@ static int host1x_probe(struct platform_
 			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_
 		host->iova_end = geometry->aperture_end;
 	}
 
+skip_iommu:
 	err = host1x_channel_list_init(&host->channel_list,
 				       host->info->nb_channels);
 	if (err) {