[PATCH v6 4/9] ACPI/IORT: Add a helper to retrieve RMR memory regions

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

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

Invoke it from the generic helper iommu_dma_get_rmrs().

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
---
 drivers/acpi/arm64/iort.c | 38 ++++++++++++++++++++++++++++++++++++++
 drivers/iommu/dma-iommu.c |  4 ++++
 include/linux/acpi_iort.h |  7 +++++++
 3 files changed, 49 insertions(+)

diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index d76ba46ebe67..3c32d62e63b6 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -809,6 +809,42 @@ static struct acpi_iort_node *iort_get_msi_resv_iommu(struct device *dev)
 	return NULL;
 }
 
+/**
+ * iort_iommu_get_rmrs() - Helper to retrieve RMR info associated with IOMMU
+ * @iommu_fwnode: fwnode for the IOMMU
+ * @head: RMR list head to be populated
+ *
+ * Returns: 0 on success, <0 failure. Please note, we will keep the already
+ *          allocated RMR reserve regions in case of a kmemdup()
+ *          failure.
+ */
+int iort_iommu_get_rmrs(struct fwnode_handle *iommu_fwnode,
+			struct list_head *head)
+{
+	struct iommu_resv_region *e;
+	struct acpi_iort_node *iommu;
+	int rmrs = 0;
+
+	iommu = iort_get_iort_node(iommu_fwnode);
+	if (!iommu || list_empty(&iort_rmr_list))
+		return -ENODEV;
+
+	list_for_each_entry(e, &iort_rmr_list, list) {
+		struct iommu_resv_region *region;
+
+		if (e->fw_data.rmr.smmu != iommu)
+			continue;
+
+		region = kmemdup(e, sizeof(*region), GFP_KERNEL);
+		if (region) {
+			list_add_tail(&region->list, head);
+			rmrs++;
+		}
+	}
+
+	return (rmrs == 0) ? -ENODEV : 0;
+}
+
 /**
  * iort_iommu_msi_get_resv_regions - Reserved region driver helper
  * @dev: Device from iommu_get_resv_regions()
@@ -1041,6 +1077,8 @@ int iort_iommu_msi_get_resv_regions(struct device *dev, struct list_head *head)
 { return 0; }
 int iort_iommu_configure_id(struct device *dev, const u32 *input_id)
 { return -ENODEV; }
+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 2fa2445e9070..1b6e27475279 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -185,6 +185,9 @@ EXPORT_SYMBOL(iommu_put_dma_cookie);
 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);
@@ -200,6 +203,7 @@ EXPORT_SYMBOL(iommu_dma_get_rmrs);
 void iommu_dma_put_rmrs(struct fwnode_handle *iommu_fwnode,
 			struct list_head *list)
 {
+	generic_iommu_put_resv_regions(iommu_fwnode->dev, list);
 }
 EXPORT_SYMBOL(iommu_dma_put_rmrs);
 
diff --git a/include/linux/acpi_iort.h b/include/linux/acpi_iort.h
index f1f0842a2cb2..d8c030c103f5 100644
--- a/include/linux/acpi_iort.h
+++ b/include/linux/acpi_iort.h
@@ -38,6 +38,8 @@ int iort_dma_get_ranges(struct device *dev, u64 *size);
 int 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)
@@ -57,6 +59,11 @@ 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