ACPI/IORT: Add support for IOMMU fwnode registration

The ACPI IORT table provide entries for IOMMU (aka SMMU in ARM world)
components that allow creating the kernel data structures required to
probe and initialize the IOMMU devices.

This patch provides support in the IORT kernel code to register IOMMU
components and their respective fwnode.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Tomasz Nowicki <tn@semihalf.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Tomasz Nowicki <tn@semihalf.com>
Cc: Hanjun Guo <hanjun.guo@linaro.org>
Cc: Tomasz Nowicki <tn@semihalf.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/acpi/arm64/iort.c

@@ -20,7 +20,9 @@
 
 #include <linux/acpi_iort.h>
 #include <linux/kernel.h>
+#include <linux/list.h>
 #include <linux/pci.h>
+#include <linux/slab.h>
 
 struct iort_its_msi_chip {
 	struct list_head	list;
@@ -28,6 +30,90 @@ struct iort_its_msi_chip {
 	u32			translation_id;
 };
 
+struct iort_fwnode {
+	struct list_head list;
+	struct acpi_iort_node *iort_node;
+	struct fwnode_handle *fwnode;
+};
+static LIST_HEAD(iort_fwnode_list);
+static DEFINE_SPINLOCK(iort_fwnode_lock);
+
+/**
+ * iort_set_fwnode() - Create iort_fwnode and use it to register
+ *		       iommu data in the iort_fwnode_list
+ *
+ * @node: IORT table node associated with the IOMMU
+ * @fwnode: fwnode associated with the IORT node
+ *
+ * Returns: 0 on success
+ *          <0 on failure
+ */
+static inline int iort_set_fwnode(struct acpi_iort_node *iort_node,
+				  struct fwnode_handle *fwnode)
+{
+	struct iort_fwnode *np;
+
+	np = kzalloc(sizeof(struct iort_fwnode), GFP_ATOMIC);
+
+	if (WARN_ON(!np))
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&np->list);
+	np->iort_node = iort_node;
+	np->fwnode = fwnode;
+
+	spin_lock(&iort_fwnode_lock);
+	list_add_tail(&np->list, &iort_fwnode_list);
+	spin_unlock(&iort_fwnode_lock);
+
+	return 0;
+}
+
+/**
+ * iort_get_fwnode() - Retrieve fwnode associated with an IORT node
+ *
+ * @node: IORT table node to be looked-up
+ *
+ * Returns: fwnode_handle pointer on success, NULL on failure
+ */
+static inline
+struct fwnode_handle *iort_get_fwnode(struct acpi_iort_node *node)
+{
+	struct iort_fwnode *curr;
+	struct fwnode_handle *fwnode = NULL;
+
+	spin_lock(&iort_fwnode_lock);
+	list_for_each_entry(curr, &iort_fwnode_list, list) {
+		if (curr->iort_node == node) {
+			fwnode = curr->fwnode;
+			break;
+		}
+	}
+	spin_unlock(&iort_fwnode_lock);
+
+	return fwnode;
+}
+
+/**
+ * iort_delete_fwnode() - Delete fwnode associated with an IORT node
+ *
+ * @node: IORT table node associated with fwnode to delete
+ */
+static inline void iort_delete_fwnode(struct acpi_iort_node *node)
+{
+	struct iort_fwnode *curr, *tmp;
+
+	spin_lock(&iort_fwnode_lock);
+	list_for_each_entry_safe(curr, tmp, &iort_fwnode_list, list) {
+		if (curr->iort_node == node) {
+			list_del(&curr->list);
+			kfree(curr);
+			break;
+		}
+	}
+	spin_unlock(&iort_fwnode_lock);
+}
+
 typedef acpi_status (*iort_find_node_callback)
 	(struct acpi_iort_node *node, void *context);