#!/usr/bin/env python2

  # SPDX-License-Identifier: GPL-2.0+

  #
  # Copyright (c) 2014 Google, Inc
  #

  # Intel microcode update tool
  
  from optparse import OptionParser
  import os
  import re
  import struct
  import sys
  
  MICROCODE_DIR = 'arch/x86/dts/microcode'
  
  class Microcode:
      """Holds information about the microcode for a particular model of CPU.
  
      Attributes:
          name:  Name of the CPU this microcode is for, including any version
                     information (e.g. 'm12206a7_00000029')
          model: Model code string (this is cpuid(1).eax, e.g. '206a7')
          words: List of hex words containing the microcode. The first 16 words
                     are the public header.
      """
      def __init__(self, name, data):
          self.name = name
          # Convert data into a list of hex words
          self.words = []
          for value in ''.join(data).split(','):
              hexval = value.strip()
              if hexval:
                  self.words.append(int(hexval, 0))
  
          # The model is in the 4rd hex word
          self.model = '%x' % self.words[3]
  
  def ParseFile(fname):
      """Parse a micrcode.dat file and return the component parts
  
      Args:
          fname: Filename to parse
      Returns:
          3-Tuple:
              date:         String containing date from the file's header
              license_text: List of text lines for the license file
              microcodes:   List of Microcode objects from the file
      """
      re_date = re.compile('/\* *(.* [0-9]{4}) *\*/$')
      re_license = re.compile('/[^-*+] *(.*)$')
      re_name = re.compile('/\* *(.*)\.inc *\*/', re.IGNORECASE)
      microcodes = {}
      license_text = []
      date = ''
      data = []
      name = None
      with open(fname) as fd:
          for line in fd:
              line = line.rstrip()
              m_date = re_date.match(line)
              m_license = re_license.match(line)
              m_name = re_name.match(line)
              if m_name:
                  if name:
                      microcodes[name] = Microcode(name, data)
                  name = m_name.group(1).lower()
                  data = []
              elif m_license:
                  license_text.append(m_license.group(1))
              elif m_date:
                  date = m_date.group(1)
              else:
                  data.append(line)
      if name:
          microcodes[name] = Microcode(name, data)
      return date, license_text, microcodes

  def ParseHeaderFiles(fname_list):
      """Parse a list of header files and return the component parts
  
      Args:
          fname_list: List of files to parse
      Returns:
              date:         String containing date from the file's header
              license_text: List of text lines for the license file
              microcodes:   List of Microcode objects from the file
      """
      microcodes = {}
      license_text = []
      date = ''
      name = None
      for fname in fname_list:
          name = os.path.basename(fname).lower()
          name = os.path.splitext(name)[0]
          data = []
          with open(fname) as fd:

              license_start = False
              license_end = False

              for line in fd:
                  line = line.rstrip()

                  if len(line) >= 2:
                      if line[0] == '/' and line[1] == '*':
                          license_start = True
                          continue
                      if line[0] == '*' and line[1] == '/':
                          license_end = True
                          continue
                  if license_start and not license_end:
                      # Ignore blank line
                      if len(line) > 0:
                          license_text.append(line)
                      continue

                  # Omit anything after the last comma
                  words = line.split(',')[:-1]
                  data += [word + ',' for word in words]
          microcodes[name] = Microcode(name, data)
      return date, license_text, microcodes

  def List(date, microcodes, model):
      """List the available microcode chunks
  
      Args:
          date:           Date of the microcode file
          microcodes:     Dict of Microcode objects indexed by name
          model:          Model string to search for, or None
      """
      print 'Date: %s' % date
      if model:
          mcode_list, tried = FindMicrocode(microcodes, model.lower())
          print 'Matching models %s:' % (', '.join(tried))
      else:
          print 'All models:'
          mcode_list = [microcodes[m] for m in microcodes.keys()]
      for mcode in mcode_list:
          print '%-20s: model %s' % (mcode.name, mcode.model)
  
  def FindMicrocode(microcodes, model):
      """Find all the microcode chunks which match the given model.
  
      This model is something like 306a9 (the value returned in eax from
      cpuid(1) when running on Intel CPUs). But we allow a partial match,
      omitting the last 1 or two characters to allow many families to have the
      same microcode.
  
      If the model name is ambiguous we return a list of matches.
  
      Args:
          microcodes: Dict of Microcode objects indexed by name
          model:      String containing model name to find
      Returns:
          Tuple:
              List of matching Microcode objects
              List of abbreviations we tried
      """
      # Allow a full name to be used
      mcode = microcodes.get(model)
      if mcode:
          return [mcode], []
  
      tried = []
      found = []
      for i in range(3):
          abbrev = model[:-i] if i else model
          tried.append(abbrev)
          for mcode in microcodes.values():
              if mcode.model.startswith(abbrev):
                  found.append(mcode)
          if found:
              break
      return found, tried

  def CreateFile(date, license_text, mcodes, outfile):

      """Create a microcode file in U-Boot's .dtsi format
  
      Args:
          date:       String containing date of original microcode file
          license:    List of text lines for the license file

          mcodes:      Microcode objects to write (normally only 1)

          outfile:    Filename to write to ('-' for stdout)
      """
      out = '''/*%s
   * ---
   * This is a device tree fragment. Use #include to add these properties to a
   * node.
   *
   * Date: %s
   */
  
  compatible = "intel,microcode";
  intel,header-version = <%d>;
  intel,update-revision = <%#x>;
  intel,date-code = <%#x>;
  intel,processor-signature = <%#x>;
  intel,checksum = <%#x>;
  intel,loader-revision = <%d>;
  intel,processor-flags = <%#x>;
  
  /* The first 48-bytes are the public header which repeats the above data */
  data = <%s
  \t>;'''
      words = ''

      add_comments = len(mcodes) > 1
      for mcode in mcodes:
          if add_comments:
              words += '
  /* %s */' % mcode.name
          for i in range(len(mcode.words)):
              if not (i & 3):
                  words += '
  '
              val = mcode.words[i]
              # Change each word so it will be little-endian in the FDT
              # This data is needed before RAM is available on some platforms so
              # we cannot do an endianness swap on boot.
              val = struct.unpack("<I", struct.pack(">I", val))[0]
              words += '\t%#010x' % val
  
      # Use the first microcode for the headers
      mcode = mcodes[0]

  
      # Take care to avoid adding a space before a tab
      text = ''
      for line in license_text:
          if line[0] == '\t':
              text += '
   *' + line
          else:
              text += '
   * ' + line
      args = [text, date]
      args += [mcode.words[i] for i in range(7)]
      args.append(words)
      if outfile == '-':
          print out % tuple(args)
      else:
          if not outfile:
              if not os.path.exists(MICROCODE_DIR):
                  print >> sys.stderr, "Creating directory '%s'" % MICROCODE_DIR
                  os.makedirs(MICROCODE_DIR)
              outfile = os.path.join(MICROCODE_DIR, mcode.name + '.dtsi')

          print >> sys.stderr, "Writing microcode for '%s' to '%s'" % (
                  ', '.join([mcode.name for mcode in mcodes]), outfile)

          with open(outfile, 'w') as fd:
              print >> fd, out % tuple(args)
  
  def MicrocodeTool():
      """Run the microcode tool"""
      commands = 'create,license,list'.split(',')
      parser = OptionParser()
      parser.add_option('-d', '--mcfile', type='string', action='store',
                      help='Name of microcode.dat file')

      parser.add_option('-H', '--headerfile', type='string', action='append',
                      help='Name of .h file containing microcode')

      parser.add_option('-m', '--model', type='string', action='store',

                      help="Model name to extract ('all' for all)")
      parser.add_option('-M', '--multiple', type='string', action='store',
                      help="Allow output of multiple models")

      parser.add_option('-o', '--outfile', type='string', action='store',
                      help='Filename to use for output (- for stdout), default is'
                      ' %s/<name>.dtsi' % MICROCODE_DIR)
      parser.usage += """ command
  
      Process an Intel microcode file (use -h for help). Commands:
  
         create     Create microcode .dtsi file for a model
         list       List available models in microcode file
         license    Print the license
  
      Typical usage:
  
         ./tools/microcode-tool -d microcode.dat -m 306a create
  
      This will find the appropriate file and write it to %s.""" % MICROCODE_DIR
  
      (options, args) = parser.parse_args()
      if not args:
          parser.error('Please specify a command')
      cmd = args[0]
      if cmd not in commands:
          parser.error("Unknown command '%s'" % cmd)

      if (not not options.mcfile) != (not not options.mcfile):
          parser.error("You must specify either header files or a microcode file, not both")
      if options.headerfile:
          date, license_text, microcodes = ParseHeaderFiles(options.headerfile)
      elif options.mcfile:
          date, license_text, microcodes = ParseFile(options.mcfile)
      else:
          parser.error('You must specify a microcode file (or header files)')

  
      if cmd == 'list':
          List(date, microcodes, options.model)
      elif cmd == 'license':
          print '
  '.join(license_text)
      elif cmd == 'create':
          if not options.model:
              parser.error('You must specify a model to create')
          model = options.model.lower()

          if options.model == 'all':
              options.multiple = True
              mcode_list = microcodes.values()
              tried = []
          else:
              mcode_list, tried = FindMicrocode(microcodes, model)

          if not mcode_list:
              parser.error("Unknown model '%s' (%s) - try 'list' to list" %
                          (model, ', '.join(tried)))

          if not options.multiple and len(mcode_list) > 1:

              parser.error("Ambiguous model '%s' (%s) matched %s - try 'list' "
                          "to list or specify a particular file" %
                          (model, ', '.join(tried),
                          ', '.join([m.name for m in mcode_list])))

          CreateFile(date, license_text, mcode_list, options.outfile)

      else:
          parser.error("Unknown command '%s'" % cmd)
  
  if __name__ == "__main__":
      MicrocodeTool()