[PATCH v3 01/16] iommu/arm-smmu: Allow client devices to select direct mapping

[Jordan Crouse]

Some client devices want to directly map the IOMMU themselves instead
of using the DMA domain. Allow those devices to opt in to direct
mapping by way of a list of compatible strings.

v3: use iommu_request_dm_for_dev() to set up a default identity domain
for a group, per Robin

Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
---

 drivers/iommu/arm-smmu.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 5e54cc0..7537639 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1235,6 +1235,35 @@ static int arm_smmu_domain_add_master(struct arm_smmu_domain *smmu_domain,
 	return 0;
 }
 
+struct arm_smmu_client_match_data {
+	bool direct_mapping;
+};
+
+static const struct arm_smmu_client_match_data qcom_adreno = {
+	.direct_mapping = true,
+};
+
+static const struct arm_smmu_client_match_data qcom_mdss = {
+	.direct_mapping = true,
+};
+
+static const struct of_device_id arm_smmu_client_of_match[] = {
+	{ .compatible = "qcom,adreno", .data = &qcom_adreno },
+	{ .compatible = "qcom,mdp4", .data = &qcom_mdss },
+	{ .compatible = "qcom,mdss", .data = &qcom_mdss },
+	{ .compatible = "qcom,sdm845-mdss", .data = &qcom_mdss },
+	{},
+};
+
+static const struct arm_smmu_client_match_data *
+arm_smmu_client_data(struct device *dev)
+{
+	const struct of_device_id *match =
+		of_match_device(arm_smmu_client_of_match, dev);
+
+	return match ? match->data : NULL;
+}
+
 static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 {
 	int ret;
@@ -1450,6 +1479,7 @@ static int arm_smmu_add_device(struct device *dev)
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master_cfg *cfg;
 	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	const struct arm_smmu_client_match_data *client;
 	int i, ret;
 
 	if (using_legacy_binding) {
@@ -1512,6 +1542,11 @@ static int arm_smmu_add_device(struct device *dev)
 	device_link_add(dev, smmu->dev,
 			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);
 
+	client = arm_smmu_client_data(dev);
+
+	if (client && client->direct_mapping)
+		iommu_request_dm_for_dev(dev);
+
 	return 0;
 
 out_cfg_free:
-- 
2.7.4