1 files changed, 105 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/pswalk.c b/drivers/acpi/acpica/pswalk.c
new file mode 100644
index 000000000..0fe3adf6b
--- /dev/null
+++ b/drivers/acpi/acpica/pswalk.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: pswalk - Parser routines to walk parsed op tree(s)
+ *
+ * Copyright (C) 2000 - 2020, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acparser.h"
+
+#define _COMPONENT          ACPI_PARSER
+ACPI_MODULE_NAME("pswalk")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ps_delete_parse_tree
+ *
+ * PARAMETERS:  subtree_root        - Root of tree (or subtree) to delete
+ *
+ * RETURN:      None
+ *
+ * DESCRIPTION: Delete a portion of or an entire parse tree.
+ *
+ ******************************************************************************/
+#include "amlcode.h"
+void acpi_ps_delete_parse_tree(union acpi_parse_object *subtree_root)
+{
+	union acpi_parse_object *op = subtree_root;
+	union acpi_parse_object *next = NULL;
+	union acpi_parse_object *parent = NULL;
+	u32 level = 0;
+
+	ACPI_FUNCTION_TRACE_PTR(ps_delete_parse_tree, subtree_root);
+
+	ACPI_DEBUG_PRINT((ACPI_DB_PARSE_TREES, " root %p\n", subtree_root));
+
+	/* Visit all nodes in the subtree */
+
+	while (op) {
+		if (op != parent) {
+
+			/* This is the descending case */
+
+			if (ACPI_IS_DEBUG_ENABLED
+			    (ACPI_LV_PARSE_TREES, _COMPONENT)) {
+
+				/* This debug option will print the entire parse tree */
+
+				acpi_os_printf("      %*.s%s %p", (level * 4),
+					       " ",
+					       acpi_ps_get_opcode_name(op->
+								       common.
+								       aml_opcode),
+					       op);
+
+				if (op->named.aml_opcode == AML_INT_NAMEPATH_OP) {
+					acpi_os_printf("  %4.4s",
+						       op->common.value.string);
+				}
+				if (op->named.aml_opcode == AML_STRING_OP) {
+					acpi_os_printf("  %s",
+						       op->common.value.string);
+				}
+				acpi_os_printf("\n");
+			}
+
+			/* Look for an argument or child of the current op */
+
+			next = acpi_ps_get_arg(op, 0);
+			if (next) {
+
+				/* Still going downward in tree (Op is not completed yet) */
+
+				op = next;
+				level++;
+				continue;
+			}
+		}
+
+		/* No more children, this Op is complete. */
+
+		next = op->common.next;
+		parent = op->common.parent;
+
+		acpi_ps_free_op(op);
+
+		/* If we are back to the starting point, the walk is complete. */
+
+		if (op == subtree_root) {
+			return_VOID;
+		}
+
+		if (next) {
+			op = next;
+		} else {
+			level--;
+			op = parent;
+		}
+	}
+
+	return_VOID;
+}