ACPICA: Namespace: Add function to directly return normalized full path

ACPICA commit 6e0229bb156d71675f2e07dc7960adb7ec0a60ea

This patch adds functions to return normalized full path instead of
"external path". The external path contains trailing "_" for each
name segment while the normalized full path doesn't contain the
trailing "_".

Currently this function is used by the method tracing users to specify a
none trailing "_" attached name path. Lv Zheng.

Note that we need to validate and switch all Linux kernel acpi_get_name()
users to use the new name type before removing the old name type from
ACPICA.

Link: https://github.com/acpica/acpica/commit/6e0229bb
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Reviewed-by: Ruiyi Zhang <ruiyi_zhang@hotmail.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 156 insertions, 119 deletions

diff --git a/drivers/acpi/acpica/nsnames.c b/drivers/acpi/acpica/nsnames.c
index 2e37888f6abe..8934b4eddb73 100644
--- a/drivers/acpi/acpica/nsnames.c
+++ b/drivers/acpi/acpica/nsnames.c
@@ -51,73 +51,6 @@ ACPI_MODULE_NAME("nsnames")
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_ns_build_external_path
- *
- * PARAMETERS:  node            - NS node whose pathname is needed
- *              size            - Size of the pathname
- *              *name_buffer    - Where to return the pathname
- *
- * RETURN:      Status
- *              Places the pathname into the name_buffer, in external format
- *              (name segments separated by path separators)
- *
- * DESCRIPTION: Generate a full pathaname
- *
- ******************************************************************************/
-acpi_status
-acpi_ns_build_external_path(struct acpi_namespace_node *node,
-			    acpi_size size, char *name_buffer)
-{
-	acpi_size index;
-	struct acpi_namespace_node *parent_node;
-
-	ACPI_FUNCTION_ENTRY();
-
-	/* Special case for root */
-
-	index = size - 1;
-	if (index < ACPI_NAME_SIZE) {
-		name_buffer[0] = AML_ROOT_PREFIX;
-		name_buffer[1] = 0;
-		return (AE_OK);
-	}
-
-	/* Store terminator byte, then build name backwards */
-
-	parent_node = node;
-	name_buffer[index] = 0;
-
-	while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
-		index -= ACPI_NAME_SIZE;
-
-		/* Put the name into the buffer */
-
-		ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
-		parent_node = parent_node->parent;
-
-		/* Prefix name with the path separator */
-
-		index--;
-		name_buffer[index] = ACPI_PATH_SEPARATOR;
-	}
-
-	/* Overwrite final separator with the root prefix character */
-
-	name_buffer[index] = AML_ROOT_PREFIX;
-
-	if (index != 0) {
-		ACPI_ERROR((AE_INFO,
-			    "Could not construct external pathname; index=%u, size=%u, Path=%s",
-			    (u32)index, (u32)size, &name_buffer[size]));
-
-		return (AE_BAD_PARAMETER);
-	}
-
-	return (AE_OK);
-}
-
-/*******************************************************************************
- *
  * FUNCTION:    acpi_ns_get_external_pathname
  *
  * PARAMETERS:  node            - Namespace node whose pathname is needed
@@ -130,37 +63,13 @@ acpi_ns_build_external_path(struct acpi_namespace_node *node,
  *              for error and debug statements.
  *
  ******************************************************************************/
-
 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 {
-	acpi_status status;
 	char *name_buffer;
-	acpi_size size;
 
 	ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
 
-	/* Calculate required buffer size based on depth below root */
-
-	size = acpi_ns_get_pathname_length(node);
-	if (!size) {
-		return_PTR(NULL);
-	}
-
-	/* Allocate a buffer to be returned to caller */
-
-	name_buffer = ACPI_ALLOCATE_ZEROED(size);
-	if (!name_buffer) {
-		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
-		return_PTR(NULL);
-	}
-
-	/* Build the path in the allocated buffer */
-
-	status = acpi_ns_build_external_path(node, size, name_buffer);
-	if (ACPI_FAILURE(status)) {
-		ACPI_FREE(name_buffer);
-		return_PTR(NULL);
-	}
+	name_buffer = acpi_ns_get_normalized_pathname(node, FALSE);
 
 	return_PTR(name_buffer);
 }
@@ -180,33 +89,12 @@ char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 {
 	acpi_size size;
-	struct acpi_namespace_node *next_node;
 
 	ACPI_FUNCTION_ENTRY();
 
-	/*
-	 * Compute length of pathname as 5 * number of name segments.
-	 * Go back up the parent tree to the root
-	 */
-	size = 0;
-	next_node = node;
+	size = acpi_ns_build_normalized_path(node, NULL, 0, FALSE);
 
-	while (next_node && (next_node != acpi_gbl_root_node)) {
-		if (ACPI_GET_DESCRIPTOR_TYPE(next_node) != ACPI_DESC_TYPE_NAMED) {
-			ACPI_ERROR((AE_INFO,
-				    "Invalid Namespace Node (%p) while traversing namespace",
-				    next_node));
-			return (0);
-		}
-		size += ACPI_PATH_SEGMENT_LENGTH;
-		next_node = next_node->parent;
-	}
-
-	if (!size) {
-		size = 1;	/* Root node case */
-	}
-
-	return (size + 1);	/* +1 for null string terminator */
+	return (size);
 }
 
 /*******************************************************************************
@@ -216,6 +104,8 @@ acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
  * PARAMETERS:  target_handle           - Handle of named object whose name is
  *                                        to be found
  *              buffer                  - Where the pathname is returned
+ *              no_trailing             - Remove trailing '_' for each name
+ *                                        segment
  *
  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
  *
@@ -225,7 +115,7 @@ acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
 
 acpi_status
 acpi_ns_handle_to_pathname(acpi_handle target_handle,
-			   struct acpi_buffer * buffer)
+			   struct acpi_buffer * buffer, u8 no_trailing)
 {
 	acpi_status status;
 	struct acpi_namespace_node *node;
@@ -240,7 +130,8 @@ acpi_ns_handle_to_pathname(acpi_handle target_handle,
 
 	/* Determine size required for the caller buffer */
 
-	required_size = acpi_ns_get_pathname_length(node);
+	required_size =
+	    acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
 	if (!required_size) {
 		return_ACPI_STATUS(AE_BAD_PARAMETER);
 	}
@@ -254,8 +145,8 @@ acpi_ns_handle_to_pathname(acpi_handle target_handle,
 
 	/* Build the path in the caller buffer */
 
-	status =
-	    acpi_ns_build_external_path(node, required_size, buffer->pointer);
+	(void)acpi_ns_build_normalized_path(node, buffer->pointer,
+					    required_size, no_trailing);
 	if (ACPI_FAILURE(status)) {
 		return_ACPI_STATUS(status);
 	}
@@ -264,3 +155,149 @@ acpi_ns_handle_to_pathname(acpi_handle target_handle,
 			  (char *)buffer->pointer, (u32) required_size));
 	return_ACPI_STATUS(AE_OK);
 }
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_build_normalized_path
+ *
+ * PARAMETERS:  node        - Namespace node
+ *              full_path   - Where the path name is returned
+ *              path_size   - Size of returned path name buffer
+ *              no_trailing - Remove trailing '_' from each name segment
+ *
+ * RETURN:      Return 1 if the AML path is empty, otherwise returning (length
+ *              of pathname + 1) which means the 'FullPath' contains a trailing
+ *              null.
+ *
+ * DESCRIPTION: Build and return a full namespace pathname.
+ *              Note that if the size of 'FullPath' isn't large enough to
+ *              contain the namespace node's path name, the actual required
+ *              buffer length is returned, and it should be greater than
+ *              'PathSize'. So callers are able to check the returning value
+ *              to determine the buffer size of 'FullPath'.
+ *
+ ******************************************************************************/
+
+u32
+acpi_ns_build_normalized_path(struct acpi_namespace_node *node,
+			      char *full_path, u32 path_size, u8 no_trailing)
+{
+	u32 length = 0, i;
+	char name[ACPI_NAME_SIZE];
+	u8 do_no_trailing;
+	char c, *left, *right;
+	struct acpi_namespace_node *next_node;
+
+	ACPI_FUNCTION_TRACE_PTR(ns_build_normalized_path, node);
+
+#define ACPI_PATH_PUT8(path, size, byte, length)    \
+	do {                                            \
+		if ((length) < (size))                      \
+		{                                           \
+			(path)[(length)] = (byte);              \
+		}                                           \
+		(length)++;                                 \
+	} while (0)
+
+	/*
+	 * Make sure the path_size is correct, so that we don't need to
+	 * validate both full_path and path_size.
+	 */
+	if (!full_path) {
+		path_size = 0;
+	}
+
+	if (!node) {
+		goto build_trailing_null;
+	}
+
+	next_node = node;
+	while (next_node && next_node != acpi_gbl_root_node) {
+		if (next_node != node) {
+			ACPI_PATH_PUT8(full_path, path_size,
+				       AML_DUAL_NAME_PREFIX, length);
+		}
+		ACPI_MOVE_32_TO_32(name, &next_node->name);
+		do_no_trailing = no_trailing;
+		for (i = 0; i < 4; i++) {
+			c = name[4 - i - 1];
+			if (do_no_trailing && c != '_') {
+				do_no_trailing = FALSE;
+			}
+			if (!do_no_trailing) {
+				ACPI_PATH_PUT8(full_path, path_size, c, length);
+			}
+		}
+		next_node = next_node->parent;
+	}
+	ACPI_PATH_PUT8(full_path, path_size, AML_ROOT_PREFIX, length);
+
+	/* Reverse the path string */
+
+	if (length <= path_size) {
+		left = full_path;
+		right = full_path + length - 1;
+		while (left < right) {
+			c = *left;
+			*left++ = *right;
+			*right-- = c;
+		}
+	}
+
+	/* Append the trailing null */
+
+build_trailing_null:
+	ACPI_PATH_PUT8(full_path, path_size, '\0', length);
+
+#undef ACPI_PATH_PUT8
+
+	return_UINT32(length);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ns_get_normalized_pathname
+ *
+ * PARAMETERS:  node            - Namespace node whose pathname is needed
+ *              no_trailing     - Remove trailing '_' from each name segment
+ *
+ * RETURN:      Pointer to storage containing the fully qualified name of
+ *              the node, In external format (name segments separated by path
+ *              separators.)
+ *
+ * DESCRIPTION: Used to obtain the full pathname to a namespace node, usually
+ *              for error and debug statements. All trailing '_' will be
+ *              removed from the full pathname if 'NoTrailing' is specified..
+ *
+ ******************************************************************************/
+
+char *acpi_ns_get_normalized_pathname(struct acpi_namespace_node *node,
+				      u8 no_trailing)
+{
+	char *name_buffer;
+	acpi_size size;
+
+	ACPI_FUNCTION_TRACE_PTR(ns_get_normalized_pathname, node);
+
+	/* Calculate required buffer size based on depth below root */
+
+	size = acpi_ns_build_normalized_path(node, NULL, 0, no_trailing);
+	if (!size) {
+		return_PTR(NULL);
+	}
+
+	/* Allocate a buffer to be returned to caller */
+
+	name_buffer = ACPI_ALLOCATE_ZEROED(size);
+	if (!name_buffer) {
+		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
+		return_PTR(NULL);
+	}
+
+	/* Build the path in the allocated buffer */
+
+	(void)acpi_ns_build_normalized_path(node, name_buffer, size,
+					    no_trailing);
+
+	return_PTR(name_buffer);
+}