#!/usr/bin/python # SPDX-License-Identifier: GPL-2.0+ # # Copyright (C) 2017 Google, Inc # Written by Simon Glass # """Device tree to platform data class This supports converting device tree data to C structures definitions and static data. """ import collections import copy import sys import fdt import fdt_util import tools # When we see these properties we ignore them - i.e. do not create a structure member PROP_IGNORE_LIST = [ '#address-cells', '#gpio-cells', '#size-cells', 'compatible', 'linux,phandle', "status", 'phandle', 'u-boot,dm-pre-reloc', 'u-boot,dm-tpl', 'u-boot,dm-spl', ] # C type declarations for the tyues we support TYPE_NAMES = { fdt.TYPE_INT: 'fdt32_t', fdt.TYPE_BYTE: 'unsigned char', fdt.TYPE_STRING: 'const char *', fdt.TYPE_BOOL: 'bool', fdt.TYPE_INT64: 'fdt64_t', } STRUCT_PREFIX = 'dtd_' VAL_PREFIX = 'dtv_' # This holds information about a property which includes phandles. # # max_args: integer: Maximum number or arguments that any phandle uses (int). # args: Number of args for each phandle in the property. The total number of # phandles is len(args). This is a list of integers. PhandleInfo = collections.namedtuple('PhandleInfo', ['max_args', 'args']) def conv_name_to_c(name): """Convert a device-tree name to a C identifier This uses multiple replace() calls instead of re.sub() since it is faster (400ms for 1m calls versus 1000ms for the 're' version). Args: name: Name to convert Return: String containing the C version of this name """ new = name.replace('@', '_at_') new = new.replace('-', '_') new = new.replace(',', '_') new = new.replace('.', '_') return new def tab_to(num_tabs, line): """Append tabs to a line of text to reach a tab stop. Args: num_tabs: Tab stop to obtain (0 = column 0, 1 = column 8, etc.) line: Line of text to append to Returns: line with the correct number of tabs appeneded. If the line already extends past that tab stop then a single space is appended. """ if len(line) >= num_tabs * 8: return line + ' ' return line + '\t' * (num_tabs - len(line) // 8) def get_value(ftype, value): """Get a value as a C expression For integers this returns a byte-swapped (little-endian) hex string For bytes this returns a hex string, e.g. 0x12 For strings this returns a literal string enclosed in quotes For booleans this return 'true' Args: type: Data type (fdt_util) value: Data value, as a string of bytes """ if ftype == fdt.TYPE_INT: return '%#x' % fdt_util.fdt32_to_cpu(value) elif ftype == fdt.TYPE_BYTE: return '%#x' % tools.ToByte(value[0]) elif ftype == fdt.TYPE_STRING: return '"%s"' % value elif ftype == fdt.TYPE_BOOL: return 'true' elif ftype == fdt.TYPE_INT64: return '%#x' % value def get_compat_name(node): """Get a node's first compatible string as a C identifier Args: node: Node object to check Return: Tuple: C identifier for the first compatible string List of C identifiers for all the other compatible strings (possibly empty) """ compat = node.props['compatible'].value aliases = [] if isinstance(compat, list): compat, aliases = compat[0], compat[1:] return conv_name_to_c(compat), [conv_name_to_c(a) for a in aliases] class DtbPlatdata(object): """Provide a means to convert device tree binary data to platform data The output of this process is C structures which can be used in space- constrained encvironments where the ~3KB code overhead of device tree code is not affordable. Properties: _fdt: Fdt object, referencing the device tree _dtb_fname: Filename of the input device tree binary file _valid_nodes: A list of Node object with compatible strings _include_disabled: true to include nodes marked status = "disabled" _outfile: The current output file (sys.stdout or a real file) _lines: Stashed list of output lines for outputting in the future """ def __init__(self, dtb_fname, include_disabled): self._fdt = None self._dtb_fname = dtb_fname self._valid_nodes = None self._include_disabled = include_disabled self._outfile = None self._lines = [] self._aliases = {} def setup_output(self, fname): """Set up the output destination Once this is done, future calls to self.out() will output to this file. Args: fname: Filename to send output to, or '-' for stdout """ if fname == '-': self._outfile = sys.stdout else: self._outfile = open(fname, 'w') def out(self, line): """Output a string to the output file Args: line: String to output """ self._outfile.write(line) def buf(self, line): """Buffer up a string to send later Args: line: String to add to our 'buffer' list """ self._lines.append(line) def get_buf(self): """Get the contents of the output buffer, and clear it Returns: The output buffer, which is then cleared for future use """ lines = self._lines self._lines = [] return lines def out_header(self): """Output a message indicating that this is an auto-generated file""" self.out('''/* * DO NOT MODIFY * * This file was generated by dtoc from a .dtb (device tree binary) file. */ ''') def get_phandle_argc(self, prop, node_name): """Check if a node contains phandles We have no reliable way of detecting whether a node uses a phandle or not. As an interim measure, use a list of known property names. Args: prop: Prop object to check Return: Number of argument cells is this is a phandle, else None """ if prop.name in ['clocks']: if not isinstance(prop.value, list): prop.value = [prop.value] val = prop.value i = 0 max_args = 0 args = [] while i < len(val): phandle = fdt_util.fdt32_to_cpu(val[i]) # If we get to the end of the list, stop. This can happen # since some nodes have more phandles in the list than others, # but we allocate enough space for the largest list. So those # nodes with shorter lists end up with zeroes at the end. if not phandle: break target = self._fdt.phandle_to_node.get(phandle) if not target: raise ValueError("Cannot parse '%s' in node '%s'" % (prop.name, node_name)) prop_name = '#clock-cells' cells = target.props.get(prop_name) if not cells: raise ValueError("Node '%s' has no '%s' property" % (target.name, prop_name)) num_args = fdt_util.fdt32_to_cpu(cells.value) max_args = max(max_args, num_args) args.append(num_args) i += 1 + num_args return PhandleInfo(max_args, args) return None def scan_dtb(self): """Scan the device tree to obtain a tree of nodes and properties Once this is done, self._fdt.GetRoot() can be called to obtain the device tree root node, and progress from there. """ self._fdt = fdt.FdtScan(self._dtb_fname) def scan_node(self, root): """Scan a node and subnodes to build a tree of node and phandle info This adds each node to self._valid_nodes. Args: root: Root node for scan """ for node in root.subnodes: if 'compatible' in node.props: status = node.props.get('status') if (not self._include_disabled and not status or status.value != 'disabled'): self._valid_nodes.append(node) # recurse to handle any subnodes self.scan_node(node) def scan_tree(self): """Scan the device tree for useful information This fills in the following properties: _valid_nodes: A list of nodes we wish to consider include in the platform data """ self._valid_nodes = [] return self.scan_node(self._fdt.GetRoot()) @staticmethod def get_num_cells(node): """Get the number of cells in addresses and sizes for this node Args: node: Node to check Returns: Tuple: Number of address cells for this node Number of size cells for this node """ parent = node.parent na, ns = 2, 2 if parent: na_prop = parent.props.get('#address-cells') ns_prop = parent.props.get('#size-cells') if na_prop: na = fdt_util.fdt32_to_cpu(na_prop.value) if ns_prop: ns = fdt_util.fdt32_to_cpu(ns_prop.value) return na, ns def scan_reg_sizes(self): """Scan for 64-bit 'reg' properties and update the values This finds 'reg' properties with 64-bit data and converts the value to an array of 64-values. This allows it to be output in a way that the C code can read. """ for node in self._valid_nodes: reg = node.props.get('reg') if not reg: continue na, ns = self.get_num_cells(node) total = na + ns if reg.type != fdt.TYPE_INT: raise ValueError("Node '%s' reg property is not an int" % node.name) if len(reg.value) % total: raise ValueError("Node '%s' reg property has %d cells " 'which is not a multiple of na + ns = %d + %d)' % (node.name, len(reg.value), na, ns)) reg.na = na reg.ns = ns if na != 1 or ns != 1: reg.type = fdt.TYPE_INT64 i = 0 new_value = [] val = reg.value if not isinstance(val, list): val = [val] while i < len(val): addr = fdt_util.fdt_cells_to_cpu(val[i:], reg.na) i += na size = fdt_util.fdt_cells_to_cpu(val[i:], reg.ns) i += ns new_value += [addr, size] reg.value = new_value def scan_structs(self): """Scan the device tree building up the C structures we will use. Build a dict keyed by C struct name containing a dict of Prop object for each struct field (keyed by property name). Where the same struct appears multiple times, try to use the 'widest' property, i.e. the one with a type which can express all others. Once the widest property is determined, all other properties are updated to match that width. """ structs = {} for node in self._valid_nodes: node_name, _ = get_compat_name(node) fields = {} # Get a list of all the valid properties in this node. for name, prop in node.props.items(): if name not in PROP_IGNORE_LIST and name[0] != '#': fields[name] = copy.deepcopy(prop) # If we've seen this node_name before, update the existing struct. if node_name in structs: struct = structs[node_name] for name, prop in fields.items(): oldprop = struct.get(name) if oldprop: oldprop.Widen(prop) else: struct[name] = prop # Otherwise store this as a new struct. else: structs[node_name] = fields upto = 0 for node in self._valid_nodes: node_name, _ = get_compat_name(node) struct = structs[node_name] for name, prop in node.props.items(): if name not in PROP_IGNORE_LIST and name[0] != '#': prop.Widen(struct[name]) upto += 1 struct_name, aliases = get_compat_name(node) for alias in aliases: self._aliases[alias] = struct_name return structs def scan_phandles(self): """Figure out what phandles each node uses We need to be careful when outputing nodes that use phandles since they must come after the declaration of the phandles in the C file. Otherwise we get a compiler error since the phandle struct is not yet declared. This function adds to each node a list of phandle nodes that the node depends on. This allows us to output things in the right order. """ for node in self._valid_nodes: node.phandles = set() for pname, prop in node.props.items(): if pname in PROP_IGNORE_LIST or pname[0] == '#': continue info = self.get_phandle_argc(prop, node.name) if info: # Process the list as pairs of (phandle, id) pos = 0 for args in info.args: phandle_cell = prop.value[pos] phandle = fdt_util.fdt32_to_cpu(phandle_cell) target_node = self._fdt.phandle_to_node[phandle] node.phandles.add(target_node) pos += 1 + args def generate_structs(self, structs): """Generate struct defintions for the platform data This writes out the body of a header file consisting of structure definitions for node in self._valid_nodes. See the documentation in README.of-plat for more information. """ self.out_header() self.out('#include \n') self.out('#include \n') # Output the struct definition for name in sorted(structs): self.out('struct %s%s {\n' % (STRUCT_PREFIX, name)) for pname in sorted(structs[name]): prop = structs[name][pname] info = self.get_phandle_argc(prop, structs[name]) if info: # For phandles, include a reference to the target struct_name = 'struct phandle_%d_arg' % info.max_args self.out('\t%s%s[%d]' % (tab_to(2, struct_name), conv_name_to_c(prop.name), len(info.args))) else: ptype = TYPE_NAMES[prop.type] self.out('\t%s%s' % (tab_to(2, ptype), conv_name_to_c(prop.name))) if isinstance(prop.value, list): self.out('[%d]' % len(prop.value)) self.out(';\n') self.out('};\n') for alias, struct_name in self._aliases.items(): if alias not in sorted(structs): self.out('#define %s%s %s%s\n'% (STRUCT_PREFIX, alias, STRUCT_PREFIX, struct_name)) def output_node(self, node): """Output the C code for a node Args: node: node to output """ struct_name, _ = get_compat_name(node) var_name = conv_name_to_c(node.name) self.buf('static const struct %s%s %s%s = {\n' % (STRUCT_PREFIX, struct_name, VAL_PREFIX, var_name)) for pname in sorted(node.props): prop = node.props[pname] if pname in PROP_IGNORE_LIST or pname[0] == '#': continue member_name = conv_name_to_c(prop.name) self.buf('\t%s= ' % tab_to(3, '.' + member_name)) # Special handling for lists if isinstance(prop.value, list): self.buf('{') vals = [] # For phandles, output a reference to the platform data # of the target node. info = self.get_phandle_argc(prop, node.name) if info: # Process the list as pairs of (phandle, id) pos = 0 for args in info.args: phandle_cell = prop.value[pos] phandle = fdt_util.fdt32_to_cpu(phandle_cell) target_node = self._fdt.phandle_to_node[phandle] name = conv_name_to_c(target_node.name) arg_values = [] for i in range(args): arg_values.append(str(fdt_util.fdt32_to_cpu(prop.value[pos + 1 + i]))) pos += 1 + args vals.append('\t{&%s%s, {%s}}' % (VAL_PREFIX, name, ', '.join(arg_values))) for val in vals: self.buf('\n\t\t%s,' % val) else: for val in prop.value: vals.append(get_value(prop.type, val)) # Put 8 values per line to avoid very long lines. for i in range(0, len(vals), 8): if i: self.buf(',\n\t\t') self.buf(', '.join(vals[i:i + 8])) self.buf('}') else: self.buf(get_value(prop.type, prop.value)) self.buf(',\n') self.buf('};\n') # Add a device declaration self.buf('U_BOOT_DEVICE(%s) = {\n' % var_name) self.buf('\t.name\t\t= "%s",\n' % struct_name) self.buf('\t.platdata\t= &%s%s,\n' % (VAL_PREFIX, var_name)) self.buf('\t.platdata_size\t= sizeof(%s%s),\n' % (VAL_PREFIX, var_name)) self.buf('};\n') self.buf('\n') self.out(''.join(self.get_buf())) def generate_tables(self): """Generate device defintions for the platform data This writes out C platform data initialisation data and U_BOOT_DEVICE() declarations for each valid node. Where a node has multiple compatible strings, a #define is used to make them equivalent. See the documentation in doc/driver-model/of-plat.txt for more information. """ self.out_header() self.out('#include \n') self.out('#include \n') self.out('#include \n') self.out('\n') nodes_to_output = list(self._valid_nodes) # Keep outputing nodes until there is none left while nodes_to_output: node = nodes_to_output[0] # Output all the node's dependencies first for req_node in node.phandles: if req_node in nodes_to_output: self.output_node(req_node) nodes_to_output.remove(req_node) self.output_node(node) nodes_to_output.remove(node) def run_steps(args, dtb_file, include_disabled, output): """Run all the steps of the dtoc tool Args: args: List of non-option arguments provided to the problem dtb_file: Filename of dtb file to process include_disabled: True to include disabled nodes output: Name of output file """ if not args: raise ValueError('Please specify a command: struct, platdata') plat = DtbPlatdata(dtb_file, include_disabled) plat.scan_dtb() plat.scan_tree() plat.scan_reg_sizes() plat.setup_output(output) structs = plat.scan_structs() plat.scan_phandles() for cmd in args[0].split(','): if cmd == 'struct': plat.generate_structs(structs) elif cmd == 'platdata': plat.generate_tables() else: raise ValueError("Unknown command '%s': (use: struct, platdata)" % cmd)