[RFC 5/5] iommu/arm-smmu: Allow direct mapping for MSI region

[Jitendra Bhivare]

Current ARM SMMU virtualizes MSI addresses to IOVA space.

In iProc SoCs, MSI needs to be steered. Allow reserving MSI address range
using DT node entry as direct region.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare at broadcom.com>
---
 drivers/iommu/arm-smmu.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 78d4c6b..7b34980 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1533,8 +1533,11 @@ static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 static void arm_smmu_get_resv_regions(struct device *dev,
 				      struct list_head *head)
 {
+	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+	struct arm_smmu_device *smmu = fwspec_smmu(fwspec);
 	struct iommu_resv_region *region;
-	int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+	struct of_iommu_resv_region of_region;
+	int index = 0, prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
 
 	region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
 					 prot, IOMMU_RESV_SW_MSI);
@@ -1543,6 +1546,15 @@ static void arm_smmu_get_resv_regions(struct device *dev,
 
 	list_add_tail(&region->list, head);
 
+	if (!of_get_resv_region(smmu->dev->of_node, "msi", &index,
+				&of_region)) {
+		region = iommu_alloc_resv_region(of_region.bus_addr,
+						 of_region.size,
+						 of_region.prot,
+						 IOMMU_RESV_DIRECT);
+		if (region)
+			list_add_tail(&region->list, head);
+	}
 	iommu_dma_get_resv_regions(dev, head);
 }
 
-- 
2.7.4