[PATCH 2/3] iommu/qcom: Use identity default domains for the MSM GPU and display

[Dmitry Baryshkov]

drm/msm writes the addresses dma_map_sgtable() returns for the DRM
device into its own page tables, so they have to be physical addresses,
i.e. the device must not use iommu-dma. qcom_iommu has no
def_domain_type, so the MDP5 and Adreno devices do get iommu-dma, the
buffers end up mapped at IOVAs of the unused default domain and the
db410c GPU fails to start.

Use identity default domains for these devices, as arm-smmu-qcom does.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at oss.qualcomm.com>
---
 drivers/iommu/arm/arm-smmu/qcom_iommu.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 54130c32056a..4a9c4cf63724 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
@@ -531,6 +532,18 @@ static bool qcom_iommu_capable(struct device *dev, enum iommu_cap cap)
 	}
 }
 
+static const struct of_device_id qcom_iommu_client_of_match[] = {
+	{ .compatible = "qcom,adreno" },
+	{ .compatible = "qcom,mdp5" },
+	{ }
+};
+
+static int qcom_iommu_def_domain_type(struct device *dev)
+{
+	return of_match_device(qcom_iommu_client_of_match, dev) ?
+		IOMMU_DOMAIN_IDENTITY : 0;
+}
+
 static struct iommu_device *qcom_iommu_probe_device(struct device *dev)
 {
 	struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
@@ -602,6 +615,7 @@ static const struct iommu_ops qcom_iommu_ops = {
 	.capable	= qcom_iommu_capable,
 	.domain_alloc_paging = qcom_iommu_domain_alloc_paging,
 	.probe_device	= qcom_iommu_probe_device,
+	.def_domain_type = qcom_iommu_def_domain_type,
 	.device_group	= generic_device_group,
 	.of_xlate	= qcom_iommu_of_xlate,
 	.default_domain_ops = &(const struct iommu_domain_ops) {

-- 
2.47.3