import fdt_util
import libfdt
from libfdt import QUIET_NOTFOUND
+import tools
# This deals with a device tree, presenting it as an assortment of Node and
# Prop objects, representing nodes and properties, respectively. This file
raise ValueError('Error %d: %s: %s' %
(errnum, libfdt.fdt_strerror(errnum), msg))
+
+def BytesToValue(data):
+ """Converts a string of bytes into a type and value
+
+ Args:
+ A bytes value (which on Python 2 is an alias for str)
+
+ Return:
+ A tuple:
+ Type of data
+ Data, either a single element or a list of elements. Each element
+ is one of:
+ TYPE_STRING: str/bytes value from the property
+ TYPE_INT: a byte-swapped integer stored as a 4-byte str/bytes
+ TYPE_BYTE: a byte stored as a single-byte str/bytes
+ """
+ data = bytes(data)
+ size = len(data)
+ strings = data.split(b'\0')
+ is_string = True
+ count = len(strings) - 1
+ if count > 0 and not len(strings[-1]):
+ for string in strings[:-1]:
+ if not string:
+ is_string = False
+ break
+ for ch in string:
+ if ch < 32 or ch > 127:
+ is_string = False
+ break
+ else:
+ is_string = False
+ if is_string:
+ if count == 1:
+ return TYPE_STRING, strings[0].decode()
+ else:
+ return TYPE_STRING, [s.decode() for s in strings[:-1]]
+ if size % 4:
+ if size == 1:
+ return TYPE_BYTE, tools.ToChar(data[0])
+ else:
+ return TYPE_BYTE, [tools.ToChar(ch) for ch in list(data)]
+ val = []
+ for i in range(0, size, 4):
+ val.append(data[i:i + 4])
+ if size == 4:
+ return TYPE_INT, val[0]
+ else:
+ return TYPE_INT, val
+
+
class Prop:
"""A device tree property
bytes
type: Value type
"""
- def __init__(self, node, offset, name, bytes):
+ def __init__(self, node, offset, name, data):
self._node = node
self._offset = offset
self.name = name
self.value = None
- self.bytes = str(bytes)
- if not bytes:
+ self.bytes = bytes(data)
+ self.dirty = False
+ if not data:
self.type = TYPE_BOOL
self.value = True
return
- self.type, self.value = self.BytesToValue(bytes)
+ self.type, self.value = BytesToValue(bytes(data))
def RefreshOffset(self, poffset):
self._offset = poffset
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
-
@classmethod
def GetEmpty(self, type):
"""Get an empty / zero value of the given type
if type == TYPE_BYTE:
return chr(0)
elif type == TYPE_INT:
- return struct.pack('<I', 0);
+ return struct.pack('>I', 0);
elif type == TYPE_STRING:
return ''
else:
self._node._fdt.CheckCache()
return self._node._fdt.GetStructOffset(self._offset)
+ def SetInt(self, val):
+ """Set the integer value of the property
+
+ The device tree is marked dirty so that the value will be written to
+ the block on the next sync.
+
+ Args:
+ val: Integer value (32-bit, single cell)
+ """
+ self.bytes = struct.pack('>I', val);
+ self.value = self.bytes
+ self.type = TYPE_INT
+ self.dirty = True
+
+ def SetData(self, bytes):
+ """Set the value of a property as bytes
+
+ Args:
+ bytes: New property value to set
+ """
+ self.bytes = bytes
+ self.type, self.value = BytesToValue(bytes)
+ self.dirty = True
+
+ def Sync(self, auto_resize=False):
+ """Sync property changes back to the device tree
+
+ This updates the device tree blob with any changes to this property
+ since the last sync.
+
+ Args:
+ auto_resize: Resize the device tree automatically if it does not
+ have enough space for the update
+
+ Raises:
+ FdtException if auto_resize is False and there is not enough space
+ """
+ if self._offset is None or self.dirty:
+ node = self._node
+ fdt_obj = node._fdt._fdt_obj
+ if auto_resize:
+ while fdt_obj.setprop(node.Offset(), self.name, self.bytes,
+ (libfdt.NOSPACE,)) == -libfdt.NOSPACE:
+ fdt_obj.resize(fdt_obj.totalsize() + 1024)
+ fdt_obj.setprop(node.Offset(), self.name, self.bytes)
+ else:
+ fdt_obj.setprop(node.Offset(), self.name, self.bytes)
+
+
class Node:
"""A device tree node
self.subnodes = []
self.props = {}
- def _FindNode(self, name):
+ def GetFdt(self):
+ """Get the Fdt object for this node
+
+ Returns:
+ Fdt object
+ """
+ return self._fdt
+
+ def FindNode(self, name):
"""Find a node given its name
Args:
del self.props[prop_name]
self._fdt.Invalidate()
+ def AddZeroProp(self, prop_name):
+ """Add a new property to the device tree with an integer value of 0.
+
+ Args:
+ prop_name: Name of property
+ """
+ self.props[prop_name] = Prop(self, None, prop_name,
+ tools.GetBytes(0, 4))
+
+ def AddEmptyProp(self, prop_name, len):
+ """Add a property with a fixed data size, for filling in later
+
+ The device tree is marked dirty so that the value will be written to
+ the blob on the next sync.
+
+ Args:
+ prop_name: Name of property
+ len: Length of data in property
+ """
+ value = tools.GetBytes(0, len)
+ self.props[prop_name] = Prop(self, None, prop_name, value)
+
+ def _CheckProp(self, prop_name):
+ """Check if a property is present
+
+ Args:
+ prop_name: Name of property
+
+ Returns:
+ self
+
+ Raises:
+ ValueError if the property is missing
+ """
+ if prop_name not in self.props:
+ raise ValueError("Fdt '%s', node '%s': Missing property '%s'" %
+ (self._fdt._fname, self.path, prop_name))
+ return self
+
+ def SetInt(self, prop_name, val):
+ """Update an integer property int the device tree.
+
+ This is not allowed to change the size of the FDT.
+
+ The device tree is marked dirty so that the value will be written to
+ the blob on the next sync.
+
+ Args:
+ prop_name: Name of property
+ val: Value to set
+ """
+ self._CheckProp(prop_name).props[prop_name].SetInt(val)
+
+ def SetData(self, prop_name, val):
+ """Set the data value of a property
+
+ The device tree is marked dirty so that the value will be written to
+ the blob on the next sync.
+
+ Args:
+ prop_name: Name of property to set
+ val: Data value to set
+ """
+ self._CheckProp(prop_name).props[prop_name].SetData(val)
+
+ def SetString(self, prop_name, val):
+ """Set the string value of a property
+
+ The device tree is marked dirty so that the value will be written to
+ the blob on the next sync.
+
+ Args:
+ prop_name: Name of property to set
+ val: String value to set (will be \0-terminated in DT)
+ """
+ if type(val) == str:
+ val = val.encode('utf-8')
+ self._CheckProp(prop_name).props[prop_name].SetData(val + b'\0')
+
+ def AddString(self, prop_name, val):
+ """Add a new string property to a node
+
+ The device tree is marked dirty so that the value will be written to
+ the blob on the next sync.
+
+ Args:
+ prop_name: Name of property to add
+ val: String value of property
+ """
+ if sys.version_info[0] >= 3: # pragma: no cover
+ val = bytes(val, 'utf-8')
+ self.props[prop_name] = Prop(self, None, prop_name, val + b'\0')
+
+ def AddSubnode(self, name):
+ """Add a new subnode to the node
+
+ Args:
+ name: name of node to add
+
+ Returns:
+ New subnode that was created
+ """
+ path = self.path + '/' + name
+ subnode = Node(self._fdt, self, None, name, path)
+ self.subnodes.append(subnode)
+ return subnode
+
+ def Sync(self, auto_resize=False):
+ """Sync node changes back to the device tree
+
+ This updates the device tree blob with any changes to this node and its
+ subnodes since the last sync.
+
+ Args:
+ auto_resize: Resize the device tree automatically if it does not
+ have enough space for the update
+
+ Raises:
+ FdtException if auto_resize is False and there is not enough space
+ """
+ if self._offset is None:
+ # The subnode doesn't exist yet, so add it
+ fdt_obj = self._fdt._fdt_obj
+ if auto_resize:
+ while True:
+ offset = fdt_obj.add_subnode(self.parent._offset, self.name,
+ (libfdt.NOSPACE,))
+ if offset != -libfdt.NOSPACE:
+ break
+ fdt_obj.resize(fdt_obj.totalsize() + 1024)
+ else:
+ offset = fdt_obj.add_subnode(self.parent._offset, self.name)
+ self._offset = offset
+
+ # Sync subnodes in reverse so that we don't disturb node offsets for
+ # nodes that are earlier in the DT. This avoids an O(n^2) rescan of
+ # node offsets.
+ for node in reversed(self.subnodes):
+ node.Sync(auto_resize)
+
+ # Sync properties now, whose offsets should not have been disturbed.
+ # We do this after subnodes, since this disturbs the offsets of these
+ # properties. Note that new properties will have an offset of None here,
+ # which Python 3 cannot sort against int. So use a large value instead
+ # to ensure that the new properties are added first.
+ prop_list = sorted(self.props.values(),
+ key=lambda prop: prop._offset or 1 << 31,
+ reverse=True)
+ for prop in prop_list:
+ prop.Sync(auto_resize)
+
+
class Fdt:
"""Provides simple access to a flat device tree blob using libfdts.
Properties:
fname: Filename of fdt
_root: Root of device tree (a Node object)
+ name: Helpful name for this Fdt for the user (useful when creating the
+ DT from data rather than a file)
"""
def __init__(self, fname):
self._fname = fname
self._cached_offsets = False
self.phandle_to_node = {}
+ self.name = ''
if self._fname:
+ self.name = self._fname
self._fname = fdt_util.EnsureCompiled(self._fname)
- with open(self._fname) as fd:
+ with open(self._fname, 'rb') as fd:
self._fdt_obj = libfdt.Fdt(fd.read())
+ @staticmethod
+ def FromData(data, name=''):
+ """Create a new Fdt object from the given data
+
+ Args:
+ data: Device-tree data blob
+ name: Helpful name for this Fdt for the user
+
+ Returns:
+ Fdt object containing the data
+ """
+ fdt = Fdt(None)
+ fdt._fdt_obj = libfdt.Fdt(bytes(data))
+ fdt.name = name
+ return fdt
+
+ def LookupPhandle(self, phandle):
+ """Look up a phandle
+
+ Args:
+ phandle: Phandle to look up (int)
+
+ Returns:
+ Node object the phandle points to
+ """
+ return self.phandle_to_node.get(phandle)
+
def Scan(self, root='/'):
"""Scan a device tree, building up a tree of Node objects
parts = path.split('/')
if len(parts) < 2:
return None
+ if len(parts) == 2 and parts[1] == '':
+ return node
for part in parts[1:]:
- node = node._FindNode(part)
+ node = node.FindNode(part)
if not node:
return None
return node
with open(self._fname, 'wb') as fd:
fd.write(self._fdt_obj.as_bytearray())
+ def Sync(self, auto_resize=False):
+ """Make sure any DT changes are written to the blob
+
+ Args:
+ auto_resize: Resize the device tree automatically if it does not
+ have enough space for the update
+
+ Raises:
+ FdtException if auto_resize is False and there is not enough space
+ """
+ self._root.Sync(auto_resize)
+ self.Invalidate()
+
def Pack(self):
"""Pack the device tree down to its minimum size
Returns:
The FDT contents as a string of bytes
"""
- return self._fdt_obj.as_bytearray()
+ return bytes(self._fdt_obj.as_bytearray())
def GetFdtObj(self):
"""Get the contents of the FDT
node = Node(fdt, parent, offset, name, path)
return node
+ def GetFilename(self):
+ """Get the filename of the device tree
+
+ Returns:
+ String filename
+ """
+ return self._fname
+
def FdtScan(fname):
- """Returns a new Fdt object from the implementation we are using"""
+ """Returns a new Fdt object"""
dtb = Fdt(fname)
dtb.Scan()
return dtb
projects / oweals / u-boot.git / blobdiff