byd: add BYD car port (HAN EV 23 / Seal Performance 2025) with MADS support

Car port adapted from HotIce0/openpilot develop_byd_comma4 to sunnypilot's
opendbc API (CP_SP signatures, (ret, ret_sp) carstate returns):

- opendbc/car/byd/: interface, carstate, carcontroller, bydcan, values,
  fingerprints (BYD_SEAL_PERFORMANCE_25 with full 91-msg fingerprint)
- opendbc/dbc/byd_common.dbc
- Brand registration: car/values.py, car/fingerprints.py (+MIGRATION),
  car.capnp SafetyModel byd @35, torque_data/params.toml
- safety/modes/byd.h: SAFETY_BYD 35U with real TX checks (steer torque
  cmd checks, longitudinal accel checks), MADS LKAS button from
  PCM_BUTTONS (944), pcm_cruise_check, ESC vehicle_moving. MISRA clean.
- safety/tests/test_byd.py: 120 tests (stock + longitudinal variants)
- opendbc/sunnypilot/car/byd/mads.py: MadsCarState tracking the
  dedicated LKAS steering wheel button
- sunnypilot/mads/mads.py: allow_always for byd (dedicated LKAS button)
- panda: restore SConstruct/SConscript build system, rebuild
  panda_h7.bin.signed (TIZI) with SAFETY_BYD + MADS lateral gating

Known limitation: BYD_HAN_EV_23 fingerprint is a subset of the Seal's,
so HAN requires FINGERPRINT=BYD_HAN_EV_23 env var (live fingerprint
cannot distinguish it; Seal fingerprints natively).

panda/SConscript

@@ -0,0 +1,176 @@
+import os
+import hashlib
+import opendbc
+import subprocess
+
+PREFIX = "arm-none-eabi-"
+BUILDER = "DEV"
+
+common_flags = []
+
+if os.getenv("RELEASE"):
+  BUILD_TYPE = "RELEASE"
+  cert_fn = os.getenv("CERT")
+  assert cert_fn is not None, 'No certificate file specified. Please set CERT env variable'
+  assert os.path.exists(cert_fn), 'Certificate file not found. Please specify absolute path'
+else:
+  BUILD_TYPE = "DEBUG"
+  cert_fn = File("./board/certs/debug").srcnode().relpath
+  common_flags += ["-DALLOW_DEBUG"]
+
+  if os.getenv("DEBUG"):
+    common_flags += ["-DDEBUG"]
+
+def objcopy(source, target, env, for_signature):
+    return '$OBJCOPY -O binary %s %s' % (source[0], target[0])
+
+def get_version(builder, build_type):
+  try:
+    git = subprocess.check_output(["git", "rev-parse", "--short=8", "HEAD"], encoding='utf8').strip()
+  except subprocess.CalledProcessError:
+    git = "unknown"
+  return f"{builder}-{git}-{build_type}"
+
+def get_key_header(name):
+  from Crypto.PublicKey import RSA
+
+  public_fn = File(f'./board/certs/{name}.pub').srcnode().get_path()
+  with open(public_fn) as f:
+    rsa = RSA.importKey(f.read())
+  assert(rsa.size_in_bits() == 1024)
+
+  rr = pow(2**1024, 2, rsa.n)
+  n0inv = 2**32 - pow(rsa.n, -1, 2**32)
+
+  r = [
+    f"RSAPublicKey {name}_rsa_key = {{",
+    f"  .len = 0x20,",
+    f"  .n0inv = {n0inv}U,",
+    f"  .n = {to_c_uint32(rsa.n)},",
+    f"  .rr = {to_c_uint32(rr)},",
+    f"  .exponent = {rsa.e},",
+    f"}};",
+  ]
+  return r
+
+def to_c_uint32(x):
+  nums = []
+  for _ in range(0x20):
+    nums.append(x % (2**32))
+    x //= (2**32)
+  return "{" + 'U,'.join(map(str, nums)) + "U}"
+
+
+def build_project(project_name, project, main, extra_flags):
+  project_dir = Dir(f'./board/obj/{project_name}/')
+
+  flags = project["FLAGS"] + extra_flags + common_flags + [
+    "-Wall",
+    "-Wextra",
+    "-Wstrict-prototypes",
+    "-Werror",
+    "-mlittle-endian",
+    "-mthumb",
+    "-nostdlib",
+    "-fno-builtin",
+    "-std=gnu11",
+    "-fmax-errors=1",
+    f"-T{File(project['LINKER_SCRIPT']).srcnode().relpath}",
+    "-fsingle-precision-constant",
+    "-Os",
+    "-g",
+  ]
+
+  env = Environment(
+    ENV=os.environ,
+    CC=PREFIX + 'gcc',
+    AS=PREFIX + 'gcc',
+    OBJCOPY=PREFIX + 'objcopy',
+    OBJDUMP=PREFIX + 'objdump',
+    OBJPREFIX=project_dir,
+    CFLAGS=flags,
+    ASFLAGS=flags,
+    LINKFLAGS=flags,
+    CPPPATH=[Dir("./"), "./board/stm32h7/inc", opendbc.INCLUDE_PATH],
+    ASCOM="$AS $ASFLAGS -o $TARGET -c $SOURCES",
+    BUILDERS={
+      'Objcopy': Builder(generator=objcopy, suffix='.bin', src_suffix='.elf')
+    },
+    tools=["default", "compilation_db"],
+  )
+
+  startup = env.Object(project["STARTUP_FILE"])
+
+  # Build bootstub
+  bs_env = env.Clone()
+  bs_env.Append(CFLAGS="-DBOOTSTUB", ASFLAGS="-DBOOTSTUB", LINKFLAGS="-DBOOTSTUB")
+  bs_elf = bs_env.Program(f"{project_dir}/bootstub.elf", [
+    startup,
+    "./board/crypto/rsa.c",
+    "./board/crypto/sha.c",
+    "./board/bootstub.c",
+  ])
+  bs_env.Objcopy(f"./board/obj/bootstub.{project_name}.bin", bs_elf)
+
+  # Build + sign main (aka app)
+  main_elf = env.Program(f"{project_dir}/main.elf", [
+    startup,
+    main
+  ], LINKFLAGS=[f"-Wl,--section-start,.isr_vector={project['APP_START_ADDRESS']}"] + flags)
+  main_bin = env.Objcopy(f"{project_dir}/main.bin", main_elf)
+  sign_py = File(f"./board/crypto/sign.py").srcnode().relpath
+  env.Command(f"./board/obj/{project_name}.bin.signed", main_bin, f"SETLEN=1 {sign_py} $SOURCE $TARGET {cert_fn}")
+
+
+
+base_project_h7 = {
+  "STARTUP_FILE": "./board/stm32h7/startup_stm32h7x5xx.s",
+  "LINKER_SCRIPT": "./board/stm32h7/stm32h7x5_flash.ld",
+  "APP_START_ADDRESS": "0x8020000",
+  "FLAGS": [
+    "-mcpu=cortex-m7",
+    "-mhard-float",
+    "-DSTM32H7",
+    "-DSTM32H725xx",
+    "-Iboard/stm32h7/inc",
+    "-mfpu=fpv5-d16",
+  ],
+}
+
+# Common autogenerated includes
+with open("board/obj/gitversion.h", "w") as f:
+  version = get_version(BUILDER, BUILD_TYPE)
+  f.write(f'extern const uint8_t gitversion[{len(version)+1}];\n')
+  f.write(f'const uint8_t gitversion[{len(version)+1}] = "{version}";\n')
+
+with open("board/obj/version", "w") as f:
+  f.write(f'{get_version(BUILDER, BUILD_TYPE)}')
+
+certs = [get_key_header(n) for n in ["debug", "release"]]
+with open("board/obj/cert.h", "w") as f:
+  for cert in certs:
+    f.write("\n".join(cert) + "\n")
+
+# Packet version defines: SHA hash of the struct header files
+def version_hash(path):
+  with open(path, "rb") as f:
+    # Normalize line endings on Windows
+    return int.from_bytes(hashlib.sha256(f.read().replace(b'\r', b'')).digest()[:4], 'little')
+hh, ch, jh = version_hash("board/health.h"), version_hash(os.path.join(opendbc.INCLUDE_PATH, "opendbc/safety/can.h")), version_hash("board/jungle/jungle_health.h")
+common_flags += [f"-DHEALTH_PACKET_VERSION=0x{hh:08X}U", f"-DCAN_PACKET_VERSION_HASH=0x{ch:08X}U",
+                 f"-DJUNGLE_HEALTH_PACKET_VERSION=0x{jh:08X}U"]
+
+# panda fw
+build_project("panda_h7", base_project_h7, "./board/main.c", [])
+
+# panda jungle fw
+flags = [
+  "-DPANDA_JUNGLE",
+]
+build_project("panda_jungle_h7", base_project_h7, "./board/jungle/main.c", flags)
+
+# body fw
+build_project("body_h7", base_project_h7, "./board/body/main.c", ["-DPANDA_BODY"])
+
+# test files
+SConscript('tests/libpanda/SConscript')

panda/SConstruct

@@ -0,0 +1,13 @@
+import os
+
+env = Environment(
+  COMPILATIONDB_USE_ABSPATH=True,
+  tools=["default", "compilation_db"],
+)
+
+SetOption('num_jobs', max(1, int((os.cpu_count() or 1)-1)))
+
+env.CompilationDatabase("compile_commands.json")
+
+# panda fw & test files
+SConscript('SConscript')

panda/board/obj/gitversion.h

@@ -1,2 +1,2 @@
-extern const uint8_t gitversion[18];
-const uint8_t gitversion[18] = "DEV-unknown-DEBUG";
+extern const uint8_t gitversion[19];
+const uint8_t gitversion[19] = "DEV-de77c89c-DEBUG";

panda/board/obj/version

@@ -1 +1 @@
-DEV-unknown-DEBUG
+DEV-de77c89c-DEBUG

panda/pandacan.egg-info/SOURCES.txt

@@ -1,6 +1,7 @@
 LICENSE
 LICENSE.md
 README.md
+__init__.py
 pyproject.toml
 ./__init__.py
 ./board/__init__.py
@@ -22,8 +23,27 @@ pyproject.toml
 ./python/spi.py
 ./python/usb.py
 ./python/utils.py
+board/__init__.py
+board/flash.py
+board/health.h
+board/recover.py
+board/body/__init__.py
+board/body/flash.py
+board/jungle/__init__.py
+board/jungle/flash.py
+board/jungle/jungle_health.h
+board/jungle/recover.py
 pandacan.egg-info/PKG-INFO
 pandacan.egg-info/SOURCES.txt
 pandacan.egg-info/dependency_links.txt
 pandacan.egg-info/requires.txt
-pandacan.egg-info/top_level.txt
+pandacan.egg-info/top_level.txt
+python/__init__.py
+python/base.py
+python/constants.py
+python/dfu.py
+python/serial.py
+python/socketpanda.py
+python/spi.py
+python/usb.py
+python/utils.py

panda/tests/libpanda/SConscript

@@ -0,0 +1,15 @@
+import opendbc
+
+env = Environment(
+  CFLAGS=[
+    '-nostdlib',
+    '-fno-builtin',
+    '-std=gnu11',
+    '-Wfatal-errors',
+    '-Wno-pointer-to-int-cast',
+  ],
+  CPPPATH=[".", "../../", "../../board/", opendbc.INCLUDE_PATH],
+)
+
+panda = env.SharedObject("panda.os", "panda.c")
+libpanda = env.SharedLibrary("libpanda.so", [panda])