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| -rwxr-xr-x | util/dtd_parser/dtd_parser.py | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/util/dtd_parser/dtd_parser.py b/util/dtd_parser/dtd_parser.py new file mode 100755 index 0000000000..bbce858a9d --- /dev/null +++ b/util/dtd_parser/dtd_parser.py @@ -0,0 +1,213 @@ +#!/usr/bin/python +# dtd_parser.py - DTD structure parser +# +# Copyright (C) 2012 The ChromiumOS Authors. All rights reserved. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; version 2 of the License +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +# + +''' +DTD string parser/generator. + +Detailed timing descriptor (DTD) is an 18 byte array describing video mode +(screen resolution, display properties, etc.) in EDID and used by Intel Option +ROM. Option ROM can support multiple video modes, specific mode is picked by +the BIOS through the appropriate Option ROM callback function. + +This program allows to interpret the 18 byte hex DTD dump, and/or modify +certain values and generate a new DTD. +''' + +import sys + +# +# The DTD array format description can be found in +# http://en.wikipedia.org/wiki/Extended_display_identification_data, (see the +# EDID Detailed Timing Descriptor section). +# +# The below dictionary describes how different DTD parameters are laid out in +# the array. Note that many parameters span multiple bit fields in the DTD. +# +# The keys in the dictionary are stings (field names), the values are tuples +# of either numbers or tri-tuples. If the element of the tuple is a number, it +# is the offset in DTD, and the entire byte is used in this field. If the +# element is a tri-tuple, its components are (DTD offset, bit shift, field +# width). +# +# The partial values are extracted from the DTD fields and concatenated +# together to form actual parameter value. +# + +dtd_descriptor = { + 'dclck' : (1, 0), + 'hor_active' : ((4, 4, 4), 2), + 'hor_blank' : ((4, 0, 4), 3), + 'vert_act' : ((7, 4, 4), 5), + 'vert_blank' : ((7, 0, 4), 6), + 'hsync_offset' : ((11, 6, 2), 8), + 'hsync_pulse_width' : ((11, 4, 2), 9), + 'vsync_offset' : ((11, 2, 2), (10, 4, 4)), + 'vsync_pulse_width' : ((11, 0, 2), (10, 0, 4)), + 'hor_image_size' : ((14, 4, 4), 12), + 'vert_image_size' : ((14, 0, 4), 13), + 'hor_border' : (15,), + 'vert_border' : (16,), + 'interlaced' : ((17, 7, 1),), + 'reserved' : ((17, 5, 2), (17, 0, 1)), + 'digital_separate' : ((17, 3, 2),), + 'vert_polarity' : ((17, 2, 1),), + 'hor_polarity' : ((17, 1, 1),), + } + +PREFIX = 'attr_' + +class DTD(object): + '''An object containing all DTD information. + + The attributes are created dynamically when the input DTD string is + parsed. For each element of the above dictionary two attributes are added: + + 'attr_<param>' to hold the actual parameter value + 'max_attr_<param>' to hold the maximum allowed value for this parameter. + ''' + + def __init__(self): + for name in dtd_descriptor: + setattr(self, PREFIX + name, 0) + + def init(self, sarray): + '''Initialize the object with values from a DTD array. + + Inputs: + + sarray: a string, an array of ASCII hex representations of the 18 DTD + bytes. + + Raises: implicitly raises ValueError or IndexError exceptions in case + the input string has less than 18 elements, or some of the + elements can not be converted to integer. + ''' + + harray = [int(x, 16) for x in sarray] + for name, desc in dtd_descriptor.iteritems(): + attr_value = 0 + total_width = 0 + for tup in desc: + if isinstance(tup, tuple): + offset, shift, width = tup + else: + offset, shift, width = tup, 0, 8 + + mask = (1 << width) - 1 + attr_value = (attr_value << width) + ( + (harray[offset] >> shift) & mask) + total_width += width + setattr(self, PREFIX + name, attr_value) + setattr(self, 'max_' + PREFIX + name, (1 << total_width) - 1) + + def __str__(self): + text = [] + for name in sorted(dtd_descriptor.keys()): + text.append('%20s: %d' % (name, getattr(self, PREFIX + name))) + return '\n'.join(text) + + def inhex(self): + '''Generate contents of the DTD as a 18 byte ASCII hex array.''' + + result = [0] * 18 + for name, desc in dtd_descriptor.iteritems(): + attr_value = getattr(self, PREFIX + name) + rdesc = list(desc) + rdesc.reverse() + for tup in rdesc: + if isinstance(tup, tuple): + offset, shift, width = tup + else: + offset, shift, width = tup, 0, 8 + + mask = (1 << width) - 1 + value = attr_value & mask + attr_value = attr_value >> width + result[offset] = (result[offset] & ~( + mask << shift)) | (value << shift) + + return ' '.join('%2.2x' % x for x in result) + + def handle_input(self, name): + '''Get user input and set a new parameter value if required. + + Display the parameter name, its current value, and prompt user for a + new value. + + If the user enters a dot, stop processing (return True). + + Empty user input means that this parameter does not have to change, + but the next parameter should be prompted. + + If input is non-empty, it is interpreted as a hex number, checked if + it fits the parameter and the new parameter value is set if checks + pass. + + Inputs: + + name - a string, parameter name, a key in dtd_descriptor + + Returns: + + Boolean, True meaning no more field are required to be modified, False + meaning that more field mods need to be prompted.. + ''' + + param = PREFIX + name + vmax = getattr(self, 'max_' + param) + new_value = raw_input('%s : %d ' % (name, getattr(self, param))) + if new_value == '': + return False + if new_value == '.': + return True + new_int = int(new_value) + if new_int > vmax: + print '%s exceeds maximum for %s (%d)' % (new_value, name, vmax) + else: + setattr(self, param, new_int) + return False + +def main(args): + if args[0] == '-m': + modify = True + base = 1 + else: + modify = False + base = 0 + + d = DTD() + d.init(args[base:]) + if modify: + for line in str(d).splitlines(): + if d.handle_input(line.split(':')[0].strip()): + break + print d + if modify: + print d.inhex() + + +if __name__ == '__main__': + try: + main(sys.argv[1:]) + except (ValueError, IndexError): + print """ +A string of 18 byte values in hex is required. +'-m' preceding the string will allow setting new parameter values. +""" + sys.exit(1) |