[PATCH 1/2] iommu/qcom: Use identity domain for GPU and display

[Rob Clark]

Similar to commit 0e764a01015d ("iommu/arm-smmu: Allow client devices to
select direct mapping") for arm-smmu-qcom, match GPU and display compat
strings to pick identity domain time.

The drm/msm driver attaches it's own domain, which it manages directly,
so we don't want an iommu managed domain interfering.

Signed-off-by: Rob Clark <robin.clark at oss.qualcomm.com>
---
 drivers/iommu/arm/arm-smmu/qcom_iommu.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 21d18ce67b98..5b10feb419d8 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>
@@ -589,6 +590,22 @@ static int qcom_iommu_of_xlate(struct device *dev,
 	return iommu_fwspec_add_ids(dev, &asid, 1);
 }
 
+static const struct of_device_id qcom_iommu_client_of_match[] = {
+	{ .compatible = "qcom,adreno" },
+	{ .compatible = "qcom,mdp4" },
+	{ .compatible = "qcom,mdp5" },
+	{ .compatible = "qcom,mdss" },
+	{ }
+};
+
+static int qcom_iommu_def_domain_type(struct device *dev)
+{
+	const struct of_device_id *match =
+		of_match_device(qcom_iommu_client_of_match, dev);
+
+	return match ? IOMMU_DOMAIN_IDENTITY : 0;
+}
+
 static const struct iommu_ops qcom_iommu_ops = {
 	.identity_domain = &qcom_iommu_identity_domain,
 	.capable	= qcom_iommu_capable,
@@ -596,6 +613,7 @@ static const struct iommu_ops qcom_iommu_ops = {
 	.probe_device	= qcom_iommu_probe_device,
 	.device_group	= generic_device_group,
 	.of_xlate	= qcom_iommu_of_xlate,
+	.def_domain_type = qcom_iommu_def_domain_type,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= qcom_iommu_attach_dev,
 		.map_pages	= qcom_iommu_map,
-- 
2.56.0