linux-kernel - [PATCH] gpu: host1x: Free the IOMMU domain when there is no device to attach

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Message-Id: <20170710193305.5987-1-contact@paulk.fr>
Date:   Mon, 10 Jul 2017 21:33:05 +0200
From:   Paul Kocialkowski <contact@...lk.fr>
To:     linux-arm-kernel@...ts.infradead.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Jonathan Hunter <jonathanh@...dia.com>,
        Stephen Warren <swarren@...dotorg.org>,
        Mikko Perttunen <mperttunen@...dia.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Paul Kocialkowski <contact@...lk.fr>
Subject: [PATCH] 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@...lk.fr>
---
 drivers/gpu/host1x/dev.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index ac65f52850a6..f296738d0de8 100644
--- 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 iommu_skip;
+		} 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;
 	}
 
+iommu_skip:
 	err = host1x_channel_list_init(host);
 	if (err) {
 		dev_err(&pdev->dev, "failed to initialize channel list\n");
-- 
2.13.1