X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=tools%2Fdtoc%2Ffdt.py;h=7fab0cd8e905b94383206ef460ba23f668568103;hb=d99894dd3a713ea6226ac39a7e332b55cf8aca49;hp=1d913a925ecc714d930506b9e16421fea1ee2966;hpb=4711e7f7af839b41a6d78490257a9e7975494dd3;p=u-boot

diff --git a/tools/dtoc/fdt.py b/tools/dtoc/fdt.py
index 1d913a925e..7fab0cd8e9 100644
--- a/tools/dtoc/fdt.py
+++ b/tools/dtoc/fdt.py
@@ -1,21 +1,32 @@
 #!/usr/bin/python
+# SPDX-License-Identifier: GPL-2.0+
 #
 # Copyright (C) 2016 Google, Inc
 # Written by Simon Glass <sjg@chromium.org>
 #
-# SPDX-License-Identifier:      GPL-2.0+
-#
+
+import struct
+import sys
 
 import fdt_util
 import libfdt
-import sys
 
-# This deals with a device tree, presenting it as a list of Node and Prop
-# objects, representing nodes and properties, respectively.
-#
+# This deals with a device tree, presenting it as an assortment of Node and
+# Prop objects, representing nodes and properties, respectively. This file
+# contains the base classes and defines the high-level API. You can use
+# FdtScan() as a convenience function to create and scan an Fdt.
+
 # This implementation uses a libfdt Python library to access the device tree,
 # so it is fairly efficient.
 
+# A list of types we support
+(TYPE_BYTE, TYPE_INT, TYPE_STRING, TYPE_BOOL, TYPE_INT64) = range(5)
+
+def CheckErr(errnum, msg):
+    if errnum:
+        raise ValueError('Error %d: %s: %s' %
+            (errnum, libfdt.fdt_strerror(errnum), msg))
+
 class Prop:
     """A device tree property
 
@@ -25,14 +36,17 @@ class Prop:
             bytes
         type: Value type
     """
-    def __init__(self, name, bytes):
+    def __init__(self, node, offset, name, bytes):
+        self._node = node
+        self._offset = offset
         self.name = name
         self.value = None
+        self.bytes = str(bytes)
         if not bytes:
-            self.type = fdt_util.TYPE_BOOL
+            self.type = TYPE_BOOL
             self.value = True
             return
-        self.type, self.value = fdt_util.BytesToValue(bytes)
+        self.type, self.value = self.BytesToValue(bytes)
 
     def GetPhandle(self):
         """Get a (single) phandle value from a property
@@ -71,10 +85,81 @@ class Prop:
             self.value = [self.value]
 
         if type(self.value) == list and len(newprop.value) > len(self.value):
-            val = fdt_util.GetEmpty(self.type)
+            val = self.GetEmpty(self.type)
             while len(self.value) < len(newprop.value):
                 self.value.append(val)
 
+    def BytesToValue(self, bytes):
+        """Converts a string of bytes into a type and value
+
+        Args:
+            A string containing bytes
+
+        Return:
+            A tuple:
+                Type of data
+                Data, either a single element or a list of elements. Each element
+                is one of:
+                    TYPE_STRING: string value from the property
+                    TYPE_INT: a byte-swapped integer stored as a 4-byte string
+                    TYPE_BYTE: a byte stored as a single-byte string
+        """
+        bytes = str(bytes)
+        size = len(bytes)
+        strings = bytes.split('\0')
+        is_string = True
+        count = len(strings) - 1
+        if count > 0 and not strings[-1]:
+            for string in strings[:-1]:
+                if not string:
+                    is_string = False
+                    break
+                for ch in string:
+                    if ch < ' ' or ch > '~':
+                        is_string = False
+                        break
+        else:
+            is_string = False
+        if is_string:
+            if count == 1:
+                return TYPE_STRING, strings[0]
+            else:
+                return TYPE_STRING, strings[:-1]
+        if size % 4:
+            if size == 1:
+                return TYPE_BYTE, bytes[0]
+            else:
+                return TYPE_BYTE, list(bytes)
+        val = []
+        for i in range(0, size, 4):
+            val.append(bytes[i:i + 4])
+        if size == 4:
+            return TYPE_INT, val[0]
+        else:
+            return TYPE_INT, val
+
+    def GetEmpty(self, type):
+        """Get an empty / zero value of the given type
+
+        Returns:
+            A single value of the given type
+        """
+        if type == TYPE_BYTE:
+            return chr(0)
+        elif type == TYPE_INT:
+            return struct.pack('<I', 0);
+        elif type == TYPE_STRING:
+            return ''
+        else:
+            return True
+
+    def GetOffset(self):
+        """Get the offset of a property
+
+        Returns:
+            The offset of the property (struct fdt_property) within the file
+        """
+        return self._node._fdt.GetStructOffset(self._offset)
 
 class Node:
     """A device tree node
@@ -88,61 +173,118 @@ class Node:
         props: A dict of properties for this node, each a Prop object.
             Keyed by property name
     """
-    def __init__(self, fdt, offset, name, path):
-        self.offset = offset
+    def __init__(self, fdt, parent, offset, name, path):
+        self._fdt = fdt
+        self.parent = parent
+        self._offset = offset
         self.name = name
         self.path = path
-        self._fdt = fdt
         self.subnodes = []
         self.props = {}
 
+    def _FindNode(self, name):
+        """Find a node given its name
+
+        Args:
+            name: Node name to look for
+        Returns:
+            Node object if found, else None
+        """
+        for subnode in self.subnodes:
+            if subnode.name == name:
+                return subnode
+        return None
+
+    def Offset(self):
+        """Returns the offset of a node, after checking the cache
+
+        This should be used instead of self._offset directly, to ensure that
+        the cache does not contain invalid offsets.
+        """
+        self._fdt.CheckCache()
+        return self._offset
+
     def Scan(self):
         """Scan a node's properties and subnodes
 
         This fills in the props and subnodes properties, recursively
         searching into subnodes so that the entire tree is built.
         """
-        self.props = self._fdt.GetProps(self.path)
+        self.props = self._fdt.GetProps(self)
+        phandle = self.props.get('phandle')
+        if phandle:
+            val = fdt_util.fdt32_to_cpu(phandle.value)
+            self._fdt.phandle_to_node[val] = self
 
-        offset = libfdt.fdt_first_subnode(self._fdt.GetFdt(), self.offset)
+        offset = libfdt.fdt_first_subnode(self._fdt.GetFdt(), self.Offset())
         while offset >= 0:
             sep = '' if self.path[-1] == '/' else '/'
-            name = libfdt.Name(self._fdt.GetFdt(), offset)
+            name = self._fdt._fdt_obj.get_name(offset)
             path = self.path + sep + name
-            node = Node(self._fdt, offset, name, path)
+            node = Node(self._fdt, self, offset, name, path)
             self.subnodes.append(node)
 
             node.Scan()
             offset = libfdt.fdt_next_subnode(self._fdt.GetFdt(), offset)
 
+    def Refresh(self, my_offset):
+        """Fix up the _offset for each node, recursively
+
+        Note: This does not take account of property offsets - these will not
+        be updated.
+        """
+        if self._offset != my_offset:
+            #print '%s: %d -> %d\n' % (self.path, self._offset, my_offset)
+            self._offset = my_offset
+        offset = libfdt.fdt_first_subnode(self._fdt.GetFdt(), self._offset)
+        for subnode in self.subnodes:
+            subnode.Refresh(offset)
+            offset = libfdt.fdt_next_subnode(self._fdt.GetFdt(), offset)
+
+    def DeleteProp(self, prop_name):
+        """Delete a property of a node
+
+        The property is deleted and the offset cache is invalidated.
+
+        Args:
+            prop_name: Name of the property to delete
+        Raises:
+            ValueError if the property does not exist
+        """
+        CheckErr(libfdt.fdt_delprop(self._fdt.GetFdt(), self.Offset(), prop_name),
+                 "Node '%s': delete property: '%s'" % (self.path, prop_name))
+        del self.props[prop_name]
+        self._fdt.Invalidate()
 
 class Fdt:
-    """Provides simple access to a flat device tree blob.
+    """Provides simple access to a flat device tree blob using libfdts.
 
     Properties:
       fname: Filename of fdt
       _root: Root of device tree (a Node object)
     """
-
     def __init__(self, fname):
-        self.fname = fname
-        with open(fname) as fd:
-            self._fdt = fd.read()
+        self._fname = fname
+        self._cached_offsets = False
+        self.phandle_to_node = {}
+        if self._fname:
+            self._fname = fdt_util.EnsureCompiled(self._fname)
 
-    def GetFdt(self):
-        """Get the contents of the FDT
+            with open(self._fname) as fd:
+                self._fdt = bytearray(fd.read())
+                self._fdt_obj = libfdt.Fdt(self._fdt)
 
-        Returns:
-            The FDT contents as a string of bytes
-        """
-        return self._fdt
-
-    def Scan(self):
+    def Scan(self, root='/'):
         """Scan a device tree, building up a tree of Node objects
 
         This fills in the self._root property
+
+        Args:
+            root: Ignored
+
+        TODO(sjg@chromium.org): Implement the 'root' parameter
         """
-        self._root = Node(self, 0, '/', '/')
+        self._root = self.Node(self, None, 0, '/', '/')
         self._root.Scan()
 
     def GetRoot(self):
@@ -153,6 +295,53 @@ class Fdt:
         """
         return self._root
 
+    def GetNode(self, path):
+        """Look up a node from its path
+
+        Args:
+            path: Path to look up, e.g. '/microcode/update@0'
+        Returns:
+            Node object, or None if not found
+        """
+        node = self._root
+        for part in path.split('/')[1:]:
+            node = node._FindNode(part)
+            if not node:
+                return None
+        return node
+
+    def Flush(self):
+        """Flush device tree changes back to the file
+
+        If the device tree has changed in memory, write it back to the file.
+        """
+        with open(self._fname, 'wb') as fd:
+            fd.write(self._fdt)
+
+    def Pack(self):
+        """Pack the device tree down to its minimum size
+
+        When nodes and properties shrink or are deleted, wasted space can
+        build up in the device tree binary.
+        """
+        CheckErr(libfdt.fdt_pack(self._fdt), 'pack')
+        fdt_len = libfdt.fdt_totalsize(self._fdt)
+        del self._fdt[fdt_len:]
+
+    def GetFdt(self):
+        """Get the contents of the FDT
+
+        Returns:
+            The FDT contents as a string of bytes
+        """
+        return self._fdt
+
+    def CheckErr(errnum, msg):
+        if errnum:
+            raise ValueError('Error %d: %s: %s' %
+                (errnum, libfdt.fdt_strerror(errnum), msg))
+
+
     def GetProps(self, node):
         """Get all properties from a node.
 
@@ -166,15 +355,60 @@ class Fdt:
         Raises:
             ValueError: if the node does not exist.
         """
-        offset = libfdt.fdt_path_offset(self._fdt, node)
-        if offset < 0:
-            libfdt.Raise(offset)
         props_dict = {}
-        poffset = libfdt.fdt_first_property_offset(self._fdt, offset)
+        poffset = libfdt.fdt_first_property_offset(self._fdt, node._offset)
         while poffset >= 0:
-            dprop, plen = libfdt.fdt_get_property_by_offset(self._fdt, poffset)
-            prop = Prop(libfdt.String(self._fdt, dprop.nameoff), libfdt.Data(dprop))
+            p = self._fdt_obj.get_property_by_offset(poffset)
+            prop = Prop(node, poffset, p.name, p.value)
             props_dict[prop.name] = prop
 
             poffset = libfdt.fdt_next_property_offset(self._fdt, poffset)
         return props_dict
+
+    def Invalidate(self):
+        """Mark our offset cache as invalid"""
+        self._cached_offsets = False
+
+    def CheckCache(self):
+        """Refresh the offset cache if needed"""
+        if self._cached_offsets:
+            return
+        self.Refresh()
+        self._cached_offsets = True
+
+    def Refresh(self):
+        """Refresh the offset cache"""
+        self._root.Refresh(0)
+
+    def GetStructOffset(self, offset):
+        """Get the file offset of a given struct offset
+
+        Args:
+            offset: Offset within the 'struct' region of the device tree
+        Returns:
+            Position of @offset within the device tree binary
+        """
+        return libfdt.fdt_off_dt_struct(self._fdt) + offset
+
+    @classmethod
+    def Node(self, fdt, parent, offset, name, path):
+        """Create a new node
+
+        This is used by Fdt.Scan() to create a new node using the correct
+        class.
+
+        Args:
+            fdt: Fdt object
+            parent: Parent node, or None if this is the root node
+            offset: Offset of node
+            name: Node name
+            path: Full path to node
+        """
+        node = Node(fdt, parent, offset, name, path)
+        return node
+
+def FdtScan(fname):
+    """Returns a new Fdt object from the implementation we are using"""
+    dtb = Fdt(fname)
+    dtb.Scan()
+    return dtb