nsaccess.c

内核linux2.4.20,可跟rtlinux3.2打补丁 组成实时linux系统,编译内核

		/* Def_field_defn defines fields in a Region */

		type_to_check_for = ACPI_TYPE_REGION;
	}

	else if (INTERNAL_TYPE_BANK_FIELD_DEFN == type) {
		/* Bank_field_defn defines data fields in a Field Object */

		type_to_check_for = ACPI_TYPE_ANY;
	}

	else {
		type_to_check_for = type;
	}


	/* TBD: [Restructure] - Move the pathname stuff into a new procedure */

	/* Examine the name pointer */

	if (!pathname) {
		/*  8-12-98 ASL Grammar Update supports null Name_path  */

		null_name_path = TRUE;
		num_segments = 0;
		this_node = acpi_gbl_root_node;

		ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
			"Null Pathname (Zero segments),  Flags=%x\n", flags));
	}

	else {
		/*
		 * Valid name pointer (Internal name format)
		 *
		 * Check for prefixes.  As represented in the AML stream, a
		 * Pathname consists of an optional scope prefix followed by
		 * a segment part.
		 *
		 * If present, the scope prefix is either a Root_prefix (in
		 * which case the name is fully qualified), or zero or more
		 * Parent_prefixes (in which case the name's scope is relative
		 * to the current scope).
		 *
		 * The segment part consists of either:
		 *  - A single 4-byte name segment, or
		 *  - A Dual_name_prefix followed by two 4-byte name segments, or
		 *  - A Multi_name_prefix_op, followed by a byte indicating the
		 *    number of segments and the segments themselves.
		 */
		if (*pathname == AML_ROOT_PREFIX) {
			/* Pathname is fully qualified, look in root name table */

			current_node = acpi_gbl_root_node;

			/* point to segment part */

			pathname++;

			ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "Searching from root [%p]\n",
				current_node));

			/* Direct reference to root, "\" */

			if (!(*pathname)) {
				this_node = acpi_gbl_root_node;
				goto check_for_new_scope_and_exit;
			}
		}

		else {
			/* Pathname is relative to current scope, start there */

			current_node = prefix_node;

			ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "Searching relative to pfx scope [%p]\n",
				prefix_node));

			/*
			 * Handle up-prefix (carat).  More than one prefix
			 * is supported
			 */
			while (*pathname == AML_PARENT_PREFIX) {
				/* Point to segment part or next Parent_prefix */

				pathname++;

				/*  Backup to the parent's scope  */

				this_node = acpi_ns_get_parent_object (current_node);
				if (!this_node) {
					/* Current scope has no parent scope */

					REPORT_ERROR (
						("Too many parent prefixes (^) - reached root\n"));
					return_ACPI_STATUS (AE_NOT_FOUND);
				}

				current_node = this_node;
			}
		}


		/*
		 * Examine the name prefix opcode, if any,
		 * to determine the number of segments
		 */
		if (*pathname == AML_DUAL_NAME_PREFIX) {
			num_segments = 2;

			/* point to first segment */

			pathname++;

			ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
				"Dual Pathname (2 segments, Flags=%X)\n", flags));
		}

		else if (*pathname == AML_MULTI_NAME_PREFIX_OP) {
			num_segments = (u32)* (u8 *) ++pathname;

			/* point to first segment */

			pathname++;

			ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
				"Multi Pathname (%d Segments, Flags=%X) \n",
				num_segments, flags));
		}

		else {
			/*
			 * No Dual or Multi prefix, hence there is only one
			 * segment and Pathname is already pointing to it.
			 */
			num_segments = 1;

			ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
				"Simple Pathname (1 segment, Flags=%X)\n", flags));
		}

#ifdef ACPI_DEBUG

		/* TBD: [Restructure] Make this a procedure */

		/* Debug only: print the entire name that we are about to lookup */

		ACPI_DEBUG_PRINT ((ACPI_DB_NAMES, "["));

		for (i = 0; i < num_segments; i++) {
			ACPI_DEBUG_PRINT_RAW ((ACPI_DB_NAMES, "%4.4s/", (char*)&pathname[i * 4]));
		}
		ACPI_DEBUG_PRINT_RAW ((ACPI_DB_NAMES, "]\n"));
#endif
	}


	/*
	 * Search namespace for each segment of the name.
	 * Loop through and verify/add each name segment.
	 */
	while (num_segments-- && current_node) {
		/*
		 * Search for the current name segment under the current
		 * named object.  The Type is significant only at the last (topmost)
		 * level.  (We don't care about the types along the path, only
		 * the type of the final target object.)
		 */
		this_search_type = ACPI_TYPE_ANY;
		if (!num_segments) {
			this_search_type = type;
			local_flags = flags;
		}

		/* Pluck one ACPI name from the front of the pathname */

		MOVE_UNALIGNED32_TO_32 (&simple_name, pathname);

		/* Try to find the ACPI name */

		status = acpi_ns_search_and_enter (simple_name, walk_state,
				   current_node, interpreter_mode,
				   this_search_type, local_flags,
				   &this_node);

		if (ACPI_FAILURE (status)) {
			if (status == AE_NOT_FOUND) {
				/* Name not found in ACPI namespace  */

				ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
					"Name [%4.4s] not found in scope %p\n",
					(char*)&simple_name, current_node));
			}

			return_ACPI_STATUS (status);
		}


		/*
		 * If 1) This is the last segment (Num_segments == 0)
		 *    2) and looking for a specific type
		 *       (Not checking for TYPE_ANY)
		 *    3) Which is not an alias
		 *    4) which is not a local type (TYPE_DEF_ANY)
		 *    5) which is not a local type (TYPE_SCOPE)
		 *    6) which is not a local type (TYPE_INDEX_FIELD_DEFN)
		 *    7) and type of object is known (not TYPE_ANY)
		 *    8) and object does not match request
		 *
		 * Then we have a type mismatch.  Just warn and ignore it.
		 */
		if ((num_segments       == 0)                               &&
			(type_to_check_for  != ACPI_TYPE_ANY)                   &&
			(type_to_check_for  != INTERNAL_TYPE_ALIAS)             &&
			(type_to_check_for  != INTERNAL_TYPE_DEF_ANY)           &&
			(type_to_check_for  != INTERNAL_TYPE_SCOPE)             &&
			(type_to_check_for  != INTERNAL_TYPE_INDEX_FIELD_DEFN)  &&
			(this_node->type    != ACPI_TYPE_ANY)                   &&
			(this_node->type    != type_to_check_for)) {
			/* Complain about a type mismatch */

			REPORT_WARNING (
				("Ns_lookup: %4.4s, type %X, checking for type %X\n",
				(char*)&simple_name, this_node->type, type_to_check_for));
		}

		/*
		 * If this is the last name segment and we are not looking for a
		 * specific type, but the type of found object is known, use that type
		 * to see if it opens a scope.
		 */
		if ((0 == num_segments) && (ACPI_TYPE_ANY == type)) {
			type = this_node->type;
		}

		if ((num_segments || acpi_ns_opens_scope (type)) &&
			(this_node->child == NULL)) {
			/*
			 * More segments or the type implies enclosed scope,
			 * and the next scope has not been allocated.
			 */
			ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Load mode=%X  This_node=%p\n",
				interpreter_mode, this_node));
		}

		current_node = this_node;

		/* point to next name segment */

		pathname += ACPI_NAME_SIZE;
	}


	/*
	 * Always check if we need to open a new scope
	 */
check_for_new_scope_and_exit:

	if (!(flags & NS_DONT_OPEN_SCOPE) && (walk_state)) {
		/*
		 * If entry is a type which opens a scope,
		 * push the new scope on the scope stack.
		 */
		if (acpi_ns_opens_scope (type_to_check_for)) {
			/*  8-12-98 ASL Grammar Update supports null Name_path  */

			if (null_name_path) {
				/* TBD: [Investigate] - is this the correct thing to do? */

				scope_to_push = NULL;
			}
			else {
				scope_to_push = this_node;
			}

			status = acpi_ds_scope_stack_push (scope_to_push, type,
					   walk_state);
			if (ACPI_FAILURE (status)) {
				return_ACPI_STATUS (status);
			}

			ACPI_DEBUG_PRINT ((ACPI_DB_INFO, "Set global scope to %p\n", scope_to_push));
		}
	}

	*return_node = this_node;
	return_ACPI_STATUS (AE_OK);
}