[PATCH 2/2] iommu/arm-smmu: Allow client devices to select direct mapping

[Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>]

From: Jordan Crouse <jcrouse@codeaurora.org>

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.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Co-developed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 drivers/iommu/arm-smmu-qcom.c | 39 +++++++++++++++++++++++++++++++++++
 drivers/iommu/arm-smmu.c      |  3 +++
 drivers/iommu/arm-smmu.h      |  5 +++++
 3 files changed, 47 insertions(+)

diff --git a/drivers/iommu/arm-smmu-qcom.c b/drivers/iommu/arm-smmu-qcom.c
index 64a4ab270ab7..ff746acd1c81 100644
--- a/drivers/iommu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm-smmu-qcom.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2019, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/of_device.h>
 #include <linux/qcom_scm.h>
 
 #include "arm-smmu.h"
@@ -11,6 +12,43 @@ struct qcom_smmu {
 	struct arm_smmu_device smmu;
 };
 
+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 qcom_smmu_client_of_match[] = {
+	{ .compatible = "qcom,adreno", .data = &qcom_adreno },
+	{ .compatible = "qcom,mdp4", .data = &qcom_mdss },
+	{ .compatible = "qcom,mdss", .data = &qcom_mdss },
+	{ .compatible = "qcom,sc7180-mdss", .data = &qcom_mdss },
+	{ .compatible = "qcom,sdm845-mdss", .data = &qcom_mdss },
+	{},
+};
+
+static const struct arm_smmu_client_match_data *
+qcom_smmu_client_data(struct device *dev)
+{
+	const struct of_device_id *match =
+		of_match_device(qcom_smmu_client_of_match, dev);
+
+	return match ? match->data : NULL;
+}
+
+static int qcom_smmu_request_domain(struct device *dev)
+{
+	const struct arm_smmu_client_match_data *client;
+
+	client = qcom_smmu_client_data(dev);
+	if (client)
+		iommu_request_dm_for_dev(dev);
+
+	return 0;
+}
+
 static int qcom_sdm845_smmu500_reset(struct arm_smmu_device *smmu)
 {
 	int ret;
@@ -41,6 +79,7 @@ static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
 }
 
 static const struct arm_smmu_impl qcom_smmu_impl = {
+	.req_domain = qcom_smmu_request_domain,
 	.reset = qcom_smmu500_reset,
 };
 
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 16c4b87af42b..67dd9326247a 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1448,6 +1448,9 @@ static int arm_smmu_add_device(struct device *dev)
 	device_link_add(dev, smmu->dev,
 			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);
 
+	if (smmu->impl && smmu->impl->req_domain)
+		return smmu->impl->req_domain(dev);
+
 	return 0;
 
 out_cfg_free:
diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h
index 8d1cd54d82a6..059dc9c39f64 100644
--- a/drivers/iommu/arm-smmu.h
+++ b/drivers/iommu/arm-smmu.h
@@ -244,6 +244,10 @@ enum arm_smmu_arch_version {
 	ARM_SMMU_V2,
 };
 
+struct arm_smmu_client_match_data {
+	bool direct_mapping;
+};
+
 enum arm_smmu_implementation {
 	GENERIC_SMMU,
 	ARM_MMU500,
@@ -386,6 +390,7 @@ struct arm_smmu_impl {
 	int (*init_context)(struct arm_smmu_domain *smmu_domain);
 	void (*tlb_sync)(struct arm_smmu_device *smmu, int page, int sync,
 			 int status);
+	int (*req_domain)(struct device *dev);
 };
 
 static inline void __iomem *arm_smmu_page(struct arm_smmu_device *smmu, int n)
-- 
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