resolve_device_tree.py

#!/usr/bin/python
"""
Resolve phandle references from a device tree capture.
"""

import argparse
import logging
import sys

def get_phandle_map(infile):
	"""
	Return a map of phandle id's to 
	"""
	phandle_map = {}

	tree_path = []
	for lineno, line in enumerate(infile):
		if line.strip().endswith('{'):
			tree_path.append(line.strip()[:-1].strip())
		elif line.strip() == '};':
			tree_path.pop(-1)
		elif '=' in line:
			lhs, rhs = line.split('=', 1)
			if lhs.strip() == 'phandle':
				key = int(rhs.strip()[1:-2], 16)
				if key in phandle_map:
					logging.warn('Duplicate phandle defined: %s on %d', key, lineno)
				else:
					phandle_map[key] = '/'.join(tree_path)
	return phandle_map

def resolve_phandles(infile, outfile, path, keys, phandle_map):
	"""
	Process each line of infile and if the treepath to that line is a subpath of `path` then 
	replace all entries with `key` in keys with the path to the referenced node
	"""

	tree_path = []
	for lineno, line in enumerate(infile):
		if line.strip().endswith('{'):
			tree_path.append(line.strip()[:-1].strip())
			outfile.write(line)
		elif line.strip() == '};':
			tree_path.pop(-1)
			outfile.write(line)
		elif '=' in line:
			if not '/'.join(tree_path).startswith(path):
				outfile.write(line)
				continue

			lhs, rhs = line.split('=', 1)
			key = lhs.strip()
			if key in keys:
				value = int(rhs.strip()[1:-2], 16)
				index_of_eq = line.find('=')
				outfile.write(line[0:index_of_eq])
				outfile.write('= [')
				outfile.write(phandle_map[value])
				outfile.write('];\n')
			else:
				outfile.write(line)

def main(argv):
	parser = argparse.ArgumentParser(description=__doc__)
	parser.add_argument('infile')
	parser.add_argument('-o', '--outfile', default='-')
	parser.add_argument('-p', '--path', default='/')
	parser.add_argument('keys', nargs=argparse.REMAINDER)
	args = parser.parse_args(argv)

	with open(args.infile, 'r') as infile:
		phandle_map = get_phandle_map(infile)

	with open(args.infile, 'r') as infile:
		if args.outfile == '-':
			outfile = sys.stdout
		else:
			outfile = open(args.outfile, 'w')
		with outfile:
			resolve_phandles(infile, outfile, args.path, args.keys, phandle_map)

if __name__ == '__main__':
	main(sys.argv[1:])