2 # SPDX-License-Identifier: GPL-2.0+
4 # Copyright (C) 2017 Google, Inc
5 # Written by Simon Glass <sjg@chromium.org>
8 """Device tree to platform data class
10 This supports converting device tree data to C structures definitions and
21 # When we see these properties we ignore them - i.e. do not create a structure member
30 'u-boot,dm-pre-reloc',
35 # C type declarations for the tyues we support
37 fdt.TYPE_INT: 'fdt32_t',
38 fdt.TYPE_BYTE: 'unsigned char',
39 fdt.TYPE_STRING: 'const char *',
40 fdt.TYPE_BOOL: 'bool',
41 fdt.TYPE_INT64: 'fdt64_t',
44 STRUCT_PREFIX = 'dtd_'
47 # This holds information about a property which includes phandles.
49 # max_args: integer: Maximum number or arguments that any phandle uses (int).
50 # args: Number of args for each phandle in the property. The total number of
51 # phandles is len(args). This is a list of integers.
52 PhandleInfo = collections.namedtuple('PhandleInfo', ['max_args', 'args'])
55 def conv_name_to_c(name):
56 """Convert a device-tree name to a C identifier
58 This uses multiple replace() calls instead of re.sub() since it is faster
59 (400ms for 1m calls versus 1000ms for the 're' version).
64 String containing the C version of this name
66 new = name.replace('@', '_at_')
67 new = new.replace('-', '_')
68 new = new.replace(',', '_')
69 new = new.replace('.', '_')
72 def tab_to(num_tabs, line):
73 """Append tabs to a line of text to reach a tab stop.
76 num_tabs: Tab stop to obtain (0 = column 0, 1 = column 8, etc.)
77 line: Line of text to append to
80 line with the correct number of tabs appeneded. If the line already
81 extends past that tab stop then a single space is appended.
83 if len(line) >= num_tabs * 8:
85 return line + '\t' * (num_tabs - len(line) // 8)
87 def get_value(ftype, value):
88 """Get a value as a C expression
90 For integers this returns a byte-swapped (little-endian) hex string
91 For bytes this returns a hex string, e.g. 0x12
92 For strings this returns a literal string enclosed in quotes
93 For booleans this return 'true'
96 type: Data type (fdt_util)
97 value: Data value, as a string of bytes
99 if ftype == fdt.TYPE_INT:
100 return '%#x' % fdt_util.fdt32_to_cpu(value)
101 elif ftype == fdt.TYPE_BYTE:
102 return '%#x' % ord(value[0])
103 elif ftype == fdt.TYPE_STRING:
104 return '"%s"' % value
105 elif ftype == fdt.TYPE_BOOL:
107 elif ftype == fdt.TYPE_INT64:
110 def get_compat_name(node):
111 """Get a node's first compatible string as a C identifier
114 node: Node object to check
117 C identifier for the first compatible string
118 List of C identifiers for all the other compatible strings
121 compat = node.props['compatible'].value
123 if isinstance(compat, list):
124 compat, aliases = compat[0], compat[1:]
125 return conv_name_to_c(compat), [conv_name_to_c(a) for a in aliases]
128 class DtbPlatdata(object):
129 """Provide a means to convert device tree binary data to platform data
131 The output of this process is C structures which can be used in space-
132 constrained encvironments where the ~3KB code overhead of device tree
133 code is not affordable.
136 _fdt: Fdt object, referencing the device tree
137 _dtb_fname: Filename of the input device tree binary file
138 _valid_nodes: A list of Node object with compatible strings
139 _include_disabled: true to include nodes marked status = "disabled"
140 _outfile: The current output file (sys.stdout or a real file)
141 _lines: Stashed list of output lines for outputting in the future
143 def __init__(self, dtb_fname, include_disabled):
145 self._dtb_fname = dtb_fname
146 self._valid_nodes = None
147 self._include_disabled = include_disabled
152 def setup_output(self, fname):
153 """Set up the output destination
155 Once this is done, future calls to self.out() will output to this
159 fname: Filename to send output to, or '-' for stdout
162 self._outfile = sys.stdout
164 self._outfile = open(fname, 'w')
167 """Output a string to the output file
170 line: String to output
172 self._outfile.write(line)
175 """Buffer up a string to send later
178 line: String to add to our 'buffer' list
180 self._lines.append(line)
183 """Get the contents of the output buffer, and clear it
186 The output buffer, which is then cleared for future use
192 def out_header(self):
193 """Output a message indicating that this is an auto-generated file"""
197 * This file was generated by dtoc from a .dtb (device tree binary) file.
202 def get_phandle_argc(self, prop, node_name):
203 """Check if a node contains phandles
205 We have no reliable way of detecting whether a node uses a phandle
206 or not. As an interim measure, use a list of known property names.
209 prop: Prop object to check
211 Number of argument cells is this is a phandle, else None
213 if prop.name in ['clocks']:
214 if not isinstance(prop.value, list):
215 prop.value = [prop.value]
222 phandle = fdt_util.fdt32_to_cpu(val[i])
223 # If we get to the end of the list, stop. This can happen
224 # since some nodes have more phandles in the list than others,
225 # but we allocate enough space for the largest list. So those
226 # nodes with shorter lists end up with zeroes at the end.
229 target = self._fdt.phandle_to_node.get(phandle)
231 raise ValueError("Cannot parse '%s' in node '%s'" %
232 (prop.name, node_name))
233 prop_name = '#clock-cells'
234 cells = target.props.get(prop_name)
236 raise ValueError("Node '%s' has no '%s' property" %
237 (target.name, prop_name))
238 num_args = fdt_util.fdt32_to_cpu(cells.value)
239 max_args = max(max_args, num_args)
240 args.append(num_args)
242 return PhandleInfo(max_args, args)
246 """Scan the device tree to obtain a tree of nodes and properties
248 Once this is done, self._fdt.GetRoot() can be called to obtain the
249 device tree root node, and progress from there.
251 self._fdt = fdt.FdtScan(self._dtb_fname)
253 def scan_node(self, root):
254 """Scan a node and subnodes to build a tree of node and phandle info
256 This adds each node to self._valid_nodes.
259 root: Root node for scan
261 for node in root.subnodes:
262 if 'compatible' in node.props:
263 status = node.props.get('status')
264 if (not self._include_disabled and not status or
265 status.value != 'disabled'):
266 self._valid_nodes.append(node)
268 # recurse to handle any subnodes
272 """Scan the device tree for useful information
274 This fills in the following properties:
275 _valid_nodes: A list of nodes we wish to consider include in the
278 self._valid_nodes = []
279 return self.scan_node(self._fdt.GetRoot())
282 def get_num_cells(node):
283 """Get the number of cells in addresses and sizes for this node
290 Number of address cells for this node
291 Number of size cells for this node
296 na_prop = parent.props.get('#address-cells')
297 ns_prop = parent.props.get('#size-cells')
299 na = fdt_util.fdt32_to_cpu(na_prop.value)
301 ns = fdt_util.fdt32_to_cpu(ns_prop.value)
304 def scan_reg_sizes(self):
305 """Scan for 64-bit 'reg' properties and update the values
307 This finds 'reg' properties with 64-bit data and converts the value to
308 an array of 64-values. This allows it to be output in a way that the
311 for node in self._valid_nodes:
312 reg = node.props.get('reg')
315 na, ns = self.get_num_cells(node)
318 if reg.type != fdt.TYPE_INT:
319 raise ValueError("Node '%s' reg property is not an int")
320 if len(reg.value) % total:
321 raise ValueError("Node '%s' reg property has %d cells "
322 'which is not a multiple of na + ns = %d + %d)' %
323 (node.name, len(reg.value), na, ns))
326 if na != 1 or ns != 1:
327 reg.type = fdt.TYPE_INT64
331 if not isinstance(val, list):
334 addr = fdt_util.fdt_cells_to_cpu(val[i:], reg.na)
336 size = fdt_util.fdt_cells_to_cpu(val[i:], reg.ns)
338 new_value += [addr, size]
339 reg.value = new_value
341 def scan_structs(self):
342 """Scan the device tree building up the C structures we will use.
344 Build a dict keyed by C struct name containing a dict of Prop
345 object for each struct field (keyed by property name). Where the
346 same struct appears multiple times, try to use the 'widest'
347 property, i.e. the one with a type which can express all others.
349 Once the widest property is determined, all other properties are
350 updated to match that width.
353 for node in self._valid_nodes:
354 node_name, _ = get_compat_name(node)
357 # Get a list of all the valid properties in this node.
358 for name, prop in node.props.items():
359 if name not in PROP_IGNORE_LIST and name[0] != '#':
360 fields[name] = copy.deepcopy(prop)
362 # If we've seen this node_name before, update the existing struct.
363 if node_name in structs:
364 struct = structs[node_name]
365 for name, prop in fields.items():
366 oldprop = struct.get(name)
372 # Otherwise store this as a new struct.
374 structs[node_name] = fields
377 for node in self._valid_nodes:
378 node_name, _ = get_compat_name(node)
379 struct = structs[node_name]
380 for name, prop in node.props.items():
381 if name not in PROP_IGNORE_LIST and name[0] != '#':
382 prop.Widen(struct[name])
385 struct_name, aliases = get_compat_name(node)
386 for alias in aliases:
387 self._aliases[alias] = struct_name
391 def scan_phandles(self):
392 """Figure out what phandles each node uses
394 We need to be careful when outputing nodes that use phandles since
395 they must come after the declaration of the phandles in the C file.
396 Otherwise we get a compiler error since the phandle struct is not yet
399 This function adds to each node a list of phandle nodes that the node
400 depends on. This allows us to output things in the right order.
402 for node in self._valid_nodes:
403 node.phandles = set()
404 for pname, prop in node.props.items():
405 if pname in PROP_IGNORE_LIST or pname[0] == '#':
407 info = self.get_phandle_argc(prop, node.name)
409 # Process the list as pairs of (phandle, id)
411 for args in info.args:
412 phandle_cell = prop.value[pos]
413 phandle = fdt_util.fdt32_to_cpu(phandle_cell)
414 target_node = self._fdt.phandle_to_node[phandle]
415 node.phandles.add(target_node)
419 def generate_structs(self, structs):
420 """Generate struct defintions for the platform data
422 This writes out the body of a header file consisting of structure
423 definitions for node in self._valid_nodes. See the documentation in
424 README.of-plat for more information.
427 self.out('#include <stdbool.h>\n')
428 self.out('#include <linux/libfdt.h>\n')
430 # Output the struct definition
431 for name in sorted(structs):
432 self.out('struct %s%s {\n' % (STRUCT_PREFIX, name))
433 for pname in sorted(structs[name]):
434 prop = structs[name][pname]
435 info = self.get_phandle_argc(prop, structs[name])
437 # For phandles, include a reference to the target
438 struct_name = 'struct phandle_%d_arg' % info.max_args
439 self.out('\t%s%s[%d]' % (tab_to(2, struct_name),
440 conv_name_to_c(prop.name),
443 ptype = TYPE_NAMES[prop.type]
444 self.out('\t%s%s' % (tab_to(2, ptype),
445 conv_name_to_c(prop.name)))
446 if isinstance(prop.value, list):
447 self.out('[%d]' % len(prop.value))
451 for alias, struct_name in self._aliases.iteritems():
452 self.out('#define %s%s %s%s\n'% (STRUCT_PREFIX, alias,
453 STRUCT_PREFIX, struct_name))
455 def output_node(self, node):
456 """Output the C code for a node
461 struct_name, _ = get_compat_name(node)
462 var_name = conv_name_to_c(node.name)
463 self.buf('static struct %s%s %s%s = {\n' %
464 (STRUCT_PREFIX, struct_name, VAL_PREFIX, var_name))
465 for pname, prop in node.props.items():
466 if pname in PROP_IGNORE_LIST or pname[0] == '#':
468 member_name = conv_name_to_c(prop.name)
469 self.buf('\t%s= ' % tab_to(3, '.' + member_name))
471 # Special handling for lists
472 if isinstance(prop.value, list):
475 # For phandles, output a reference to the platform data
476 # of the target node.
477 info = self.get_phandle_argc(prop, node.name)
479 # Process the list as pairs of (phandle, id)
481 for args in info.args:
482 phandle_cell = prop.value[pos]
483 phandle = fdt_util.fdt32_to_cpu(phandle_cell)
484 target_node = self._fdt.phandle_to_node[phandle]
485 name = conv_name_to_c(target_node.name)
487 for i in range(args):
488 arg_values.append(str(fdt_util.fdt32_to_cpu(prop.value[pos + 1 + i])))
490 vals.append('\t{&%s%s, {%s}}' % (VAL_PREFIX, name,
491 ', '.join(arg_values)))
493 self.buf('\n\t\t%s,' % val)
495 for val in prop.value:
496 vals.append(get_value(prop.type, val))
498 # Put 8 values per line to avoid very long lines.
499 for i in xrange(0, len(vals), 8):
502 self.buf(', '.join(vals[i:i + 8]))
505 self.buf(get_value(prop.type, prop.value))
509 # Add a device declaration
510 self.buf('U_BOOT_DEVICE(%s) = {\n' % var_name)
511 self.buf('\t.name\t\t= "%s",\n' % struct_name)
512 self.buf('\t.platdata\t= &%s%s,\n' % (VAL_PREFIX, var_name))
513 self.buf('\t.platdata_size\t= sizeof(%s%s),\n' % (VAL_PREFIX, var_name))
517 self.out(''.join(self.get_buf()))
519 def generate_tables(self):
520 """Generate device defintions for the platform data
522 This writes out C platform data initialisation data and
523 U_BOOT_DEVICE() declarations for each valid node. Where a node has
524 multiple compatible strings, a #define is used to make them equivalent.
526 See the documentation in doc/driver-model/of-plat.txt for more
530 self.out('#include <common.h>\n')
531 self.out('#include <dm.h>\n')
532 self.out('#include <dt-structs.h>\n')
534 nodes_to_output = list(self._valid_nodes)
536 # Keep outputing nodes until there is none left
537 while nodes_to_output:
538 node = nodes_to_output[0]
539 # Output all the node's dependencies first
540 for req_node in node.phandles:
541 if req_node in nodes_to_output:
542 self.output_node(req_node)
543 nodes_to_output.remove(req_node)
544 self.output_node(node)
545 nodes_to_output.remove(node)
548 def run_steps(args, dtb_file, include_disabled, output):
549 """Run all the steps of the dtoc tool
552 args: List of non-option arguments provided to the problem
553 dtb_file: Filename of dtb file to process
554 include_disabled: True to include disabled nodes
555 output: Name of output file
558 raise ValueError('Please specify a command: struct, platdata')
560 plat = DtbPlatdata(dtb_file, include_disabled)
563 plat.scan_reg_sizes()
564 plat.setup_output(output)
565 structs = plat.scan_structs()
568 for cmd in args[0].split(','):
570 plat.generate_structs(structs)
571 elif cmd == 'platdata':
572 plat.generate_tables()
574 raise ValueError("Unknown command '%s': (use: struct, platdata)" %