ACPI/IORT: Add a helper to retrieve RMR info directly

This will provide a way for SMMU drivers to retrieve StreamIDs
associated with IORT RMR nodes and use that to set bypass settings
for those IDs.

Tested-by: Steven Price <steven.price@arm.com>
Tested-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20220615101044.1972-6-shameerali.kolothum.thodi@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/acpi/arm64/iort.c

@@ -1394,6 +1394,34 @@ int iort_dma_get_ranges(struct device *dev, u64 *size)
 		return nc_dma_get_range(dev, size);
 }
 
+/**
+ * iort_get_rmr_sids - Retrieve IORT RMR node reserved regions with
+ *                     associated StreamIDs information.
+ * @iommu_fwnode: fwnode associated with IOMMU
+ * @head: Resereved region list
+ */
+void iort_get_rmr_sids(struct fwnode_handle *iommu_fwnode,
+		       struct list_head *head)
+{
+	iort_iommu_rmr_get_resv_regions(iommu_fwnode, NULL, head);
+}
+EXPORT_SYMBOL_GPL(iort_get_rmr_sids);
+
+/**
+ * iort_put_rmr_sids - Free memory allocated for RMR reserved regions.
+ * @iommu_fwnode: fwnode associated with IOMMU
+ * @head: Resereved region list
+ */
+void iort_put_rmr_sids(struct fwnode_handle *iommu_fwnode,
+		       struct list_head *head)
+{
+	struct iommu_resv_region *entry, *next;
+
+	list_for_each_entry_safe(entry, next, head, list)
+		entry->free(NULL, entry);
+}
+EXPORT_SYMBOL_GPL(iort_put_rmr_sids);
+
 static void __init acpi_iort_register_irq(int hwirq, const char *name,
 					  int trigger,
 					  struct resource *res)

include/linux/acpi_iort.h

@@ -33,6 +33,10 @@ struct irq_domain *iort_get_device_domain(struct device *dev, u32 id,
 					  enum irq_domain_bus_token bus_token);
 void acpi_configure_pmsi_domain(struct device *dev);
 int iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id);
+void iort_get_rmr_sids(struct fwnode_handle *iommu_fwnode,
+		       struct list_head *head);
+void iort_put_rmr_sids(struct fwnode_handle *iommu_fwnode,
+		       struct list_head *head);
 /* IOMMU interface */
 int iort_dma_get_ranges(struct device *dev, u64 *size);
 int iort_iommu_configure_id(struct device *dev, const u32 *id_in);
@@ -46,6 +50,10 @@ static inline struct irq_domain *iort_get_device_domain(
 	struct device *dev, u32 id, enum irq_domain_bus_token bus_token)
 { return NULL; }
 static inline void acpi_configure_pmsi_domain(struct device *dev) { }
+static inline
+void iort_get_rmr_sids(struct fwnode_handle *iommu_fwnode, struct list_head *head) { }
+static inline
+void iort_put_rmr_sids(struct fwnode_handle *iommu_fwnode, struct list_head *head) { }
 /* IOMMU interface */
 static inline int iort_dma_get_ranges(struct device *dev, u64 *size)
 { return -ENODEV; }