util/apcb/apcb_v3_edit.py

   1 #!/usr/bin/env python3
   2
   3 # Script for editing APCB_V3 binaries, such as injecting SPDs.
   4
   5 import sys
   6 import re
   7 import argparse
   8 from collections import namedtuple
   9 from struct import *
  10 import binascii
  11 import os
  12
  13 # SPD_MAGIC matches the expected SPD header:
  14 # Byte 0 = 0x23 = 512 bytes total / 384 bytes used
  15 # Byte 1 = 0x11 = Revision 1.1
  16 # Byte 2 = 0x11 = LPDDR4X SDRAM
  17 #        = 0x13 = LP5 SDRAM
  18 #        = 0x15 = LP5X SDRAM
  19 # Byte 3 = 0x0E = Non-DIMM Solution
  20 LP4_SPD_MAGIC = bytes.fromhex('2311110E')
  21 LP5_SPD_MAGIC = bytes.fromhex('2311130E')
  22 LP5X_SPD_MAGIC = bytes.fromhex('2311150E')
  23 EMPTY_SPD = b'\x00' * 512
  24
  25 spd_ssp_struct_fmt = '??B?IIBBBxIIBBBx'
  26 spd_ssp_struct = namedtuple(
  27     'spd_ssp_struct', 'SpdValid, DimmPresent, \
  28                     PageAddress, NvDimmPresent, \
  29                     DramManufacturersIDCode, Address, \
  30                     SpdMuxPresent, MuxI2CAddress, MuxChannel, \
  31                     Technology, Package, SocketNumber, \
  32                     ChannelNumber, DimmNumber')
  33
  34 apcb_v3_header_fmt = 'HHHHBBBBBBH'
  35 apcb_v3_header = namedtuple(
  36     'apcb_v3_header', 'GroupId, TypeId, SizeOfType, \
  37     InstanceId, ContextType, ContextFormat, UnitSize, \
  38     PriorityMask, KeySize, KeyPos, BoardMask')
  39
  40 def parseargs():
  41     parser = argparse.ArgumentParser(description='Inject SPDs into APCB binaries')
  42     parser.add_argument(
  43         'apcb_in',
  44         type=str,
  45         help='APCB input file')
  46     parser.add_argument(
  47         'apcb_out',
  48         type=str,
  49         help='APCB output file')
  50     parser.add_argument(
  51         '--spd_sources',
  52         nargs='+',
  53         help='List of SPD sources')
  54     parser.add_argument(
  55         '--mem_type',
  56         type=str,
  57         default='lp4',
  58         help='Memory type [lp4|lp5|lp5x]. Default = lp4')
  59     return parser.parse_args()
  60
  61
  62 def chksum(data):
  63     sum = 0
  64     for b in data[:16] + data[17:]:
  65         sum = (sum + b) & 0xff
  66     return (0x100 - sum) & 0xff
  67
  68
  69 def inject(orig, insert, offset):
  70     return b''.join([orig[:offset], insert, orig[offset + len(insert):]])
  71
  72
  73 def main():
  74     spd_magic = LP4_SPD_MAGIC
  75
  76     args = parseargs()
  77
  78     print(f'Reading input APCB from {args.apcb_in}')
  79
  80     with open(args.apcb_in, 'rb') as f:
  81         apcb = f.read()
  82
  83     orig_apcb_len = len(apcb)
  84
  85     assert chksum(apcb) == apcb[16], f'ERROR: {args.apcb_in} checksum is invalid'
  86
  87     print(f'Using SPD Sources = {args.spd_sources}')
  88
  89     if args.mem_type == 'lp5':
  90         spd_magic = LP5_SPD_MAGIC
  91     elif args.mem_type == 'lp5x':
  92         spd_magic = LP5X_SPD_MAGIC
  93
  94     spds = []
  95     for spd_source in args.spd_sources:
  96         with open(spd_source, 'rb') as f:
  97             spd_data = bytes.fromhex(re.sub(r'\s+', '', f.read().decode()))
  98         assert(len(spd_data) == 512), f'ERROR: {spd_source} not 512 bytes'
  99         spds.append(spd_data)
 100
 101     spd_offset = 0
 102     instance = 0
 103     while True:
 104         spd_offset = apcb.find(spd_magic, spd_offset)
 105         if spd_offset < 0:
 106             print('No more SPD magic numbers in APCB')
 107             break
 108
 109         spd_ssp_offset = spd_offset - calcsize(spd_ssp_struct_fmt)
 110         spd_ssp_bytes = apcb[spd_ssp_offset:spd_offset]
 111         spd_ssp = spd_ssp_struct._make(
 112             unpack(spd_ssp_struct_fmt, spd_ssp_bytes))
 113
 114         assert spd_ssp.DimmNumber >= 0 and spd_ssp.DimmNumber <= 1, \
 115                 'ERROR: Unexpected dimm number found in APCB'
 116         assert spd_ssp.ChannelNumber >= 0 and spd_ssp.ChannelNumber <= 1, \
 117                 'ERROR: Unexpected channel number found in APCB'
 118
 119         print(f'Found SPD instance {instance} with channel {spd_ssp.ChannelNumber} '
 120               f'and dimm {spd_ssp.DimmNumber} at offset {spd_offset}')
 121
 122         # APCB V3 header is above first channel 0 entry
 123         if spd_ssp.ChannelNumber == 0:
 124             apcb_v3_header_offset = spd_ssp_offset - \
 125                 calcsize(apcb_v3_header_fmt) - 4
 126             apcb_v3_header_bytes = apcb[apcb_v3_header_offset:
 127                                         apcb_v3_header_offset + calcsize(apcb_v3_header_fmt)]
 128             apcb_v3 = apcb_v3_header._make(
 129                 unpack(apcb_v3_header_fmt, apcb_v3_header_bytes))
 130             apcb_v3 = apcb_v3._replace(BoardMask=(1 << instance))
 131
 132         if instance < len(spds):
 133             print(f'Enabling channel {spd_ssp.ChannelNumber}, '
 134                   f'dimm {spd_ssp.DimmNumber} and injecting SPD')
 135             spd_ssp = spd_ssp._replace(SpdValid=True, DimmPresent=True)
 136             spd = spds[instance]
 137         else:
 138              print(f'Disabling channel {spd_ssp.ChannelNumber}, '
 139                    f'dimm {spd_ssp.DimmNumber} and clearing SPD')
 140              spd_ssp = spd_ssp._replace(SpdValid=False, DimmPresent=False)
 141              spd = EMPTY_SPD
 142
 143         assert len(spd) == 512, f'ERROR: Expected SPD to be 512 bytes, got {len(spd)}'
 144
 145         apcb = inject(apcb, pack(spd_ssp_struct_fmt, *spd_ssp), spd_ssp_offset)
 146         apcb = inject(apcb, spd, spd_offset)
 147         if spd_ssp.ChannelNumber == 0:
 148             apcb = inject(apcb, pack(apcb_v3_header_fmt, *apcb_v3), apcb_v3_header_offset)
 149         else:
 150             instance += 1
 151
 152         spd_offset += 512
 153
 154     assert instance >= len(spds), \
 155             f'ERROR: Not enough SPD slots in APCB, found {instance}, need {len(spds)}'
 156
 157     print(f'Fixing checksum and writing to {args.apcb_out}')
 158
 159     apcb = inject(apcb, bytes([chksum(apcb)]), 16)
 160
 161     assert chksum(apcb) == apcb[16], 'ERROR: Final checksum is invalid'
 162     assert orig_apcb_len == len(apcb), \
 163                 'ERROR: The size of the APCB binary changed.'
 164
 165     print(f'Writing {len(apcb)} bytes to {args.apcb_out}')
 166
 167     with open(args.apcb_out, 'wb') as f:
 168         f.write(apcb)
 169
 170
 171 if __name__ == "__main__":
 172     main()