[PATCH v3 09/10] iommu/arm-smmu: Get associated RMR info and install bypass SMR

[Shameer Kolothum]

From: Jon Nettleton <jon at solid-run.com>

Check if there is any RMR info associated with the devices behind
the SMMU and if any, install bypass SMRs for them. This is to
keep any ongoing traffic associated with these devices alive
when we enable/reset SMMU during probe().

Signed-off-by: Jon Nettleton <jon at solid-run.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
---
 drivers/iommu/arm/arm-smmu/arm-smmu.c | 42 +++++++++++++++++++++++++++
 drivers/iommu/arm/arm-smmu/arm-smmu.h |  2 ++
 2 files changed, 44 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index d8c6bfde6a61..4d2f91626d87 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -2102,6 +2102,43 @@ err_reset_platform_ops: __maybe_unused;
 	return err;
 }
 
+static void arm_smmu_rmr_install_bypass_smr(struct arm_smmu_device *smmu)
+{
+	struct iommu_rmr *e;
+	int i, cnt = 0;
+	u32 smr;
+
+	for (i = 0; i < smmu->num_mapping_groups; i++) {
+		smr = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_SMR(i));
+		if (!FIELD_GET(ARM_SMMU_SMR_VALID, smr))
+			continue;
+
+		list_for_each_entry(e, &smmu->rmr_list, list) {
+			if (FIELD_GET(ARM_SMMU_SMR_ID, smr) != e->sid)
+				continue;
+
+			smmu->smrs[i].id = FIELD_GET(ARM_SMMU_SMR_ID, smr);
+			smmu->smrs[i].mask = FIELD_GET(ARM_SMMU_SMR_MASK, smr);
+			smmu->smrs[i].valid = true;
+
+			smmu->s2crs[i].type = S2CR_TYPE_BYPASS;
+			smmu->s2crs[i].privcfg = S2CR_PRIVCFG_DEFAULT;
+			smmu->s2crs[i].cbndx = 0xff;
+
+			cnt++;
+		}
+	}
+
+	dev_notice(smmu->dev, "\tpreserved %d boot mapping%s\n", cnt,
+		   cnt == 1 ? "" : "s");
+}
+
+static int arm_smmu_get_rmr(struct arm_smmu_device *smmu)
+{
+	INIT_LIST_HEAD(&smmu->rmr_list);
+	return iommu_dma_get_rmrs(dev_fwnode(smmu->dev), &smmu->rmr_list);
+}
+
 static int arm_smmu_device_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -2231,6 +2268,11 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 	}
 
 	platform_set_drvdata(pdev, smmu);
+
+	/* Check for RMRs and install bypass SMRs if any */
+	if (!arm_smmu_get_rmr(smmu))
+		arm_smmu_rmr_install_bypass_smr(smmu);
+
 	arm_smmu_device_reset(smmu);
 	arm_smmu_test_smr_masks(smmu);
 
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
index d2a2d1bc58ba..ca9559eb8733 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
@@ -326,6 +326,8 @@ struct arm_smmu_device {
 
 	/* IOMMU core code handle */
 	struct iommu_device		iommu;
+
+	struct list_head		rmr_list;
 };
 
 enum arm_smmu_context_fmt {
-- 
2.17.1