util/apcb: Add apcb_edit tool

On the Picasso architecture, the PSP is responsible for setting up DRAM
before releasing the x86. The APCB (AGESA PSP Configuration Block)
contains multiple SPDs and the GPIO numbers used to select the correct
SPD. Since the source to build the APCBs is not public, it can't be
built as part of the coreboot build. To work around this problem, we use
a template APCB and inject the relevant information.

BUG=b:147042464

Signed-off-by: Rob Barnes <robbarnes@google.com>
Change-Id: I88a09743f8e8a184c47071ee5e417f5b6bdb7467
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/coreboot/+/2123799
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41380
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>

2 files changed, 188 insertions, 0 deletions

diff --git a/util/apcb/README b/util/apcb/README
new file mode 100644
index 000000000000..a765f4d9bd93
--- /dev/null
+++ b/util/apcb/README
@@ -0,0 +1,3 @@
+The necessary tools for building APCBs are not available for use by coreboot.
+This tool allows patching an existing APCB binary with specific SPDs
+and GPIO selection pins.
diff --git a/util/apcb/apcb_edit.py b/util/apcb/apcb_edit.py
new file mode 100755
index 000000000000..4a7e683ebed8
--- /dev/null
+++ b/util/apcb/apcb_edit.py
@@ -0,0 +1,185 @@
+#! /usr/bin/env python
+
+# Script for editing APCB binaries, such as injecting SPDs and GPIO
+# configurations.
+
+import sys
+import re
+import argparse
+from collections import namedtuple
+from struct import *
+
+GPIO_MAGIC = bytes.fromhex('fadeddad' * 3)
+SPD_MAGIC = bytes.fromhex('f005ba110000')
+EMPTY_SPD = b'\x00' * 512
+
+spd_ssp_struct_fmt = '??B?IIBBBxIIBBBx'
+spd_ssp_struct = namedtuple(
+    'spd_ssp_struct', 'SpdValid, DimmPresent, \
+                    PageAddress, NvDimmPresent, \
+                    DramManufacturersIDCode, Address, \
+                    SpdMuxPresent, MuxI2CAddress, MuxChannel, \
+                    Technology, Package, SocketNumber, \
+                    ChannelNumber, DimmNumber')
+
+
+def parseargs():
+    parser = argparse.ArgumentParser(description='Inject SPDs and SPD GPIO \
+                     selection pins into APCB binaries')
+    parser.add_argument(
+        'apcb_in',
+        nargs='?',
+        type=argparse.FileType('rb'),
+        default=sys.stdin,
+        help='APCB input file')
+    parser.add_argument(
+        'apcb_out',
+        nargs='?',
+        type=argparse.FileType('wb'),
+        default=sys.stdout,
+        help='APCB output file')
+    parser.add_argument(
+        '--spd_0_0',
+        type=argparse.FileType('r'),
+        help='SPD input file for channel 0, dimm 0')
+    parser.add_argument(
+        '--spd_0_1',
+        type=argparse.FileType('r'),
+        help='SPD input file for channel 0, dimm 1')
+    parser.add_argument(
+        '--spd_1_0',
+        type=argparse.FileType('r'),
+        help='SPD input file for channel 1, dimm 0')
+    parser.add_argument(
+        '--spd_1_1',
+        type=argparse.FileType('r'),
+        help='SPD input file for channel 1, dimm 1')
+    parser.add_argument(
+        '--hex',
+        action='store_true',
+        help='SPD input file is hex encoded, binary otherwise')
+    parser.add_argument(
+        '--board_id_gpio0',
+        type=int,
+        required=True,
+        nargs=3,
+        help='Board ID GPIO 0: NUMBER IO_MUX BANK_CTRL')
+    parser.add_argument(
+        '--board_id_gpio1',
+        type=int,
+        required=True,
+        nargs=3,
+        help='Board ID GPIO 1: NUMBER IO_MUX BANK_CTRL')
+    parser.add_argument(
+        '--board_id_gpio2',
+        type=int,
+        required=True,
+        nargs=3,
+        help='Board ID GPIO 2: NUMBER IO_MUX BANK_CTRL')
+    parser.add_argument(
+        '--board_id_gpio3',
+        type=int,
+        required=True,
+        nargs=3,
+        help='Board ID GPIO 3: NUMBER IO_MUX BANK_CTRL')
+    return parser.parse_args()
+
+
+def chksum(data):
+    sum = 0
+    for b in data[:16] + data[17:]:
+        sum = (sum + b) & 0xff
+    return (0x100 - sum) & 0xff
+
+
+def inject(orig, insert, offset):
+    return b''.join([orig[:offset], insert, orig[offset + len(insert):]])
+
+
+def main():
+    args = parseargs()
+
+    print("Reading input APCB from %s\n" % (args.apcb_in.name))
+
+    apcb = args.apcb_in.read()
+
+    orig_apcb_len = len(apcb)
+
+    gpio_offset = apcb.find(GPIO_MAGIC)
+    assert gpio_offset > 0, "GPIO magic number not found"
+    print('GPIO magic number found at offset 0x%x\n' % gpio_offset)
+    gpio_array = (args.board_id_gpio0 + args.board_id_gpio1 +
+                  args.board_id_gpio2 + args.board_id_gpio3)
+    print('Writing SPD GPIO array %s\n' % gpio_array)
+    apcb = inject(apcb, pack('BBBBBBBBBBBB', *gpio_array), gpio_offset)
+
+    spd_offset = 0
+    while True:
+        spd_offset = apcb.find(SPD_MAGIC, spd_offset)
+        if spd_offset < 0:
+            break
+
+        spd_ssp_offset = spd_offset - calcsize(spd_ssp_struct_fmt)
+        spd_ssp_bytes = apcb[spd_ssp_offset:spd_offset]
+        spd_ssp = spd_ssp_struct._make(
+            unpack(spd_ssp_struct_fmt, spd_ssp_bytes))
+
+        assert spd_ssp.DimmNumber >= 0 and spd_ssp.DimmNumber <= 1, \
+                "Unexpected dimm number found in APCB"
+        assert spd_ssp.ChannelNumber >= 0 and spd_ssp.ChannelNumber <= 1, \
+                "Unexpected channel number found in APCB"
+
+        print("Found SPD magic number with channel %d and dimm %d "
+              "at offset 0x%x\n" % (spd_ssp.ChannelNumber, spd_ssp.DimmNumber,
+                                    spd_offset))
+
+        dimm_channel = (spd_ssp.ChannelNumber, spd_ssp.DimmNumber)
+        spd = None
+        if dimm_channel == (0, 0) and args.spd_0_0:
+            spd = args.spd_0_0.read()
+        elif dimm_channel == (0, 1) and args.spd_0_1:
+            spd = args.spd_0_1.read()
+        elif dimm_channel == (1, 0) and args.spd_1_0:
+            spd = args.spd_1_0.read()
+        elif dimm_channel == (1, 1) and args.spd_1_1:
+            spd = args.spd_1_0.read()
+
+        if spd:
+            if args.hex:
+                spd = re.sub(r'#.*', '', spd)
+                spd = re.sub(r'\s+', '', spd)
+                spd = bytes.fromhex(spd)
+            else:
+                spd = spd.encode()
+
+            assert len(spd) == 512, \
+                            "Expected SPD to be 512 bytes, got %d" % len(spd)
+
+            print("Enabling channel %d, dimm %d and injecting SPD\n" %
+                  (spd_ssp.ChannelNumber, spd_ssp.DimmNumber))
+            spd_ssp = spd_ssp._replace(SpdValid=True, DimmPresent=True)
+
+        else:
+            print("Disabling channel %d, dimm %d and clearing SPD\n" %
+                  (spd_ssp.ChannelNumber, spd_ssp.DimmNumber))
+            spd_ssp = spd_ssp._replace(SpdValid=False, DimmPresent=False)
+            spd = EMPTY_SPD
+
+        apcb = inject(apcb, pack(spd_ssp_struct_fmt, *spd_ssp), spd_ssp_offset)
+        apcb = inject(apcb, spd, spd_offset)
+
+        spd_offset += 512
+
+    print("Fixing checksum and writing to %s\n" % (args.apcb_out.name))
+
+    apcb = inject(apcb, bytes([chksum(apcb)]), 16)
+
+    assert chksum(apcb) == apcb[16], "Checksum is invalid"
+    assert orig_apcb_len == len(apcb), \
+                "The size of the APCB binary changed, this should not happen."
+
+    args.apcb_out.write(apcb)
+
+
+if __name__ == "__main__":
+    main()