[PATCH 3/3] iommu/arm-smmu-qcom: Add support for the interconnect

[Parikshit Pareek <quic_ppareek@quicinc.com>]

Introduce support to detect the interconnect, and set its bandwidth.
For certain targets, we need to set the bandwidth of interconnect,
connecting smmu to memory. This is accessed during memory mapped IO
access to smmu registers, and during page tables walks.

Reported-by: Eric Chanudet <echanude@redhat.com>
Signed-off-by: Parikshit Pareek <quic_ppareek@quicinc.com>
---
 drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
index c71afda79d64..6961d564869b 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
@@ -8,6 +8,7 @@
 #include <linux/delay.h>
 #include <linux/of_device.h>
 #include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/interconnect.h>
 
 #include "arm-smmu.h"
 #include "arm-smmu-qcom.h"
@@ -549,6 +550,8 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
 {
 	const struct device_node *np = smmu->dev->of_node;
 	const struct of_device_id *match;
+	struct icc_path *icc_path;
+	int ret, icc_bw;
 
 #ifdef CONFIG_ACPI
 	if (np == NULL) {
@@ -558,6 +561,19 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
 	}
 #endif
 
+	icc_path = devm_of_icc_get(smmu->dev, "tbu_mc");
+	if (IS_ERR(icc_path))
+		return (struct arm_smmu_device *)icc_path;
+
+	ret = of_property_read_u32(np, "icc_bw", &icc_bw);
+
+	/*if interconnect exists, check for the  bandwidth value*/
+	if (icc_path && !ret) {
+		ret = icc_set_bw(icc_path, 0, MBps_to_icc(icc_bw));
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
 	match = of_match_node(qcom_smmu_impl_of_match, np);
 	if (match)
 		return qcom_smmu_create(smmu, match->data);
-- 
2.17.1