[PATCH v4 3/8] ACPI/IORT: Add a helper to retrieve RMR memory regions

[Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>]

Add a helper function that retrieves RMR memory descriptors
associated with a given IOMMU. This will be used by IOMMU
drivers to setup necessary mappings.

Now that we have this, invoke it from the generic helper
interface.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
---
 drivers/acpi/arm64/iort.c | 40 +++++++++++++++++++++++++++++++++++++++
 drivers/iommu/dma-iommu.c |  3 +++
 include/linux/acpi_iort.h |  7 +++++++
 3 files changed, 50 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index fea1ffaedf3b..6ca88c38987a 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -12,6 +12,7 @@
 
 #include <linux/acpi_iort.h>
 #include <linux/bitfield.h>
+#include <linux/dma-iommu.h>
 #include <linux/iommu.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
@@ -837,6 +838,43 @@ static inline int iort_add_device_replay(struct device *dev)
 	return err;
 }
 
+/**
+ * iort_iommu_get_rmrs - Helper to retrieve RMR info associated with IOMMU
+ * @iommu: fwnode for the IOMMU
+ * @head: RMR list head to be populated
+ *
+ * Returns: 0 on success, <0 failure
+ */
+int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
+			struct list_head *head)
+{
+	struct iort_rmr_entry *e;
+	struct acpi_iort_node *iommu;
+
+	iommu = iort_get_iort_node(iommu_fwnode);
+	if (!iommu)
+		return -EINVAL;
+
+	list_for_each_entry(e, &iort_rmr_list, list) {
+		struct acpi_iort_rmr_desc *rmr_desc;
+		struct iommu_rmr *rmr;
+
+		if (e->smmu != iommu)
+			continue;
+
+		rmr_desc = e->rmr_desc;
+		rmr = iommu_dma_alloc_rmr(rmr_desc->base_address,
+					  rmr_desc->length, e->sid,
+					  e->flags);
+		if (!rmr)
+			return -ENOMEM;
+
+		list_add_tail(&rmr->list, head);
+	}
+
+	return 0;
+}
+
 /**
  * iort_iommu_msi_get_resv_regions - Reserved region driver helper
  * @dev: Device from iommu_get_resv_regions()
@@ -1108,6 +1146,8 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 						const u32 *input_id)
 { return NULL; }
+int iort_iommu_get_rmrs(struct fwnode_handle *fwnode, struct list_head *head)
+{ return -ENODEV; }
 #endif
 
 static int nc_dma_get_range(struct device *dev, u64 *size)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 674bd8815159..2d9caf548a32 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -203,6 +203,9 @@ EXPORT_SYMBOL(iommu_dma_get_resv_regions);
 int iommu_dma_get_rmrs(struct fwnode_handle *iommu_fwnode,
 		       struct list_head *list)
 {
+	if (!is_of_node(iommu_fwnode))
+		return iort_iommu_get_rmrs(iommu_fwnode, list);
+
 	return -EINVAL;
 }
 EXPORT_SYMBOL(iommu_dma_get_rmrs);
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index 1a12baa58e40..e8c45fa59531 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -39,6 +39,8 @@ const struct iommu_ops *iort_iommu_configure_id(struct device *dev,
 						const u32 *id_in);
 int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head);
 phys_addr_t acpi_iort_dma_get_max_cpu_address(void);
+int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
+			struct list_head *list);
 #else
 static inline void acpi_iort_init(void) { }
 static inline u32 iort_msi_map_id(struct device *dev, u32 id)
@@ -59,6 +61,11 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 
 static inline phys_addr_t acpi_iort_dma_get_max_cpu_address(void)
 { return PHYS_ADDR_MAX; }
+
+static inline
+int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
+			struct list_head *list)
+{ return -ENODEV; }
 #endif
 
 #endif /* __ACPI_IORT_H__ */
-- 
2.17.1