asahi_firmware.multitouch: Add M2 MTFW firmware collection

While this code technically works for the Touch Bar firmware too, it
seems quite likely that the kernel will need a different representation
than this serialized plist nonsense for that, so for now this is limited
to M2 trackpad multitouch firmware.

Signed-off-by: Hector Martin <marcan@marcan.st>

asahi_firmware/multitouch.py

@@ -0,0 +1,178 @@
+# SPDX-License-Identifier: MIT
+import xml.etree.ElementTree as ET
+import plistlib, base64, struct, os, logging
+from .img4 import img4p_extract
+from .core import FWFile
+
+log = logging.getLogger("asahi_firmware.multitouch")
+
+def load_plist_xml(d):
+    root = ET.fromstring(d.decode("ascii"))
+
+    idmap = {}
+    def unmunge(el, idmap):
+        if "ID" in el.attrib:
+            idmap[el.attrib["ID"]] = el
+        if "IDREF" in el.attrib:
+            return idmap[el.attrib["IDREF"]]
+        else:
+            el2 = ET.Element(el.tag)
+            el2.text = el.text
+            el2.tag = el.tag
+            el2.attrib = el.attrib
+            for child in el:
+                el2.append(unmunge(child, idmap))
+
+            return el2
+    pl = ET.Element("plist")
+    pl.append(unmunge(root, idmap))
+
+    return plistlib.loads(ET.tostring(pl))
+
+def plist_to_bin(plist):
+    iface_offset = None
+
+    for i in plist:
+        if i["Type"] == "Config":
+            for j in i["Config"]["Interface Config"]:
+                j["bInterfaceNumber"] = None
+
+    def serialize(o):
+        if o is None:
+            yield None
+        elif o is True:
+            yield bytes([0xf5])
+        elif isinstance(o, dict):
+            l = len(o)
+            if l < 0x10:
+                yield bytes([0xa0 + l])
+            else:
+                raise Exception("Unsupported serializer case")
+                yield b"?"
+            for k, v in o.items():
+                yield from serialize(k)
+                yield from serialize(v)
+        elif isinstance(o, list):
+            l = len(o)
+            if l < 0x18:
+                yield bytes([0x80 + l])
+            else:
+                raise Exception("Unsupported serializer case")
+                yield b"?"
+            for v in o:
+                yield from serialize(v)
+        elif isinstance(o, str):
+            o = o.encode("utf-8") + b"\0"
+            l = len(o)
+            if l < 0x18:
+                yield bytes([0x60 + l])
+            elif l <= 0xff:
+                yield bytes([0x78, l])
+            else:
+                raise Exception("Unsupported serializer case")
+                yield b"?"
+            yield o
+        elif isinstance(o, int):
+            if o < 0x18:
+                yield bytes([o])
+            elif o <= 0xff:
+                yield bytes([0x18, o])
+            elif o <= 0xffff:
+                yield bytes([0x19])
+                yield struct.pack(">H", o)
+            else:
+                yield bytes([0x1a])
+                yield struct.pack(">I", o)
+        elif isinstance(o, bytes):
+            if len(o) <= 0xffff:
+                yield (4, 3)
+                yield struct.pack(">BH", 0x59, len(o))
+            else:
+                raise Exception("Unsupported serializer case")
+                yield b"?" + struct.pack(">I", len(o))
+            yield o
+        else:
+            raise Exception("Unsupported serializer case")
+            yield b"?" + str(type(o)).encode("ascii")
+
+    def add_padding(l):
+        nonlocal iface_offset
+        off = 0
+        for b in l:
+            if b is None:
+                assert iface_offset is None
+                iface_offset = off
+                b = b"\x00"
+            if isinstance(b, tuple):
+                align, i = b
+                if (off + i) % align != 0:
+                    pad = align - ((off + i) % align)
+                    off += pad
+                    yield b"\xd3" * pad
+            else:
+                off += len(b)
+                yield b
+
+    blob = b"".join(add_padding(serialize(plist)))
+
+    assert iface_offset is not None
+
+    hdr = struct.pack("<4sIII", b"HIDF", 1, 32, len(blob))
+    hdr += struct.pack("<I12x", iface_offset)
+    assert len(hdr) == 32
+
+    return hdr + blob
+
+class MultitouchFWCollection(object):
+    def __init__(self, source_path):
+        self.fwfiles = []
+        self.load(source_path)
+
+    def load(self, source_path):
+        if not os.path.exists(source_path):
+            #log.warning("fud_firmware is missing. You may need to update your stub with the Asahi Linux installer for Touch Bar functionality.")
+            return
+
+        for fname in os.listdir(source_path):
+            if fname.startswith("j"):
+                self.do_machine(fname, os.path.join(source_path, fname))
+
+    def do_machine(self, machine, path):
+        mtfw = os.path.join(path, "Multitouch.im4p")
+        if not os.path.exists(mtfw):
+            return
+
+        log.info(f"Processing {machine}")
+
+        with open(mtfw, "rb") as fd:
+            im4p = fd.read()
+
+        name, xml = img4p_extract(im4p)
+
+        assert name == "mtfw"
+
+        plist = load_plist_xml(xml.rstrip(b"\x00"))
+
+        collected = set()
+        for key, val in plist.items():
+            # Touchpad firmwares only for now
+            if not key.startswith("C1FD0"):
+                log.info(f"  Skipping {key}")
+                continue
+
+            log.info(f"  Collecting {key}")
+            filename = f"apple/tpmtfw-{machine}.bin"
+
+            if filename in collected:
+                raise Exception(f"Tried to collect firmware {filename} twice!")
+
+            data = plist_to_bin(val)
+            fw = FWFile(filename, data)
+            self.fwfiles.append((filename, fw))
+
+            collected.add(filename)
+            log.info(f"  Collected {key} as {filename}")
+
+    def files(self):
+        return self.fwfiles
+

asahi_firmware/update.py

@@ -4,6 +4,7 @@
 from .core import FWPackage
 from .wifi import WiFiFWCollection
 from .bluetooth import BluetoothFWCollection
+from .multitouch import MultitouchFWCollection
 
 def update_firmware(source, dest, manifest):
     raw_fw = source.joinpath("all_firmware.tar.gz")
@@ -15,11 +16,16 @@ def update_firmware(source, dest, manifest):
     with tempfile.TemporaryDirectory() as tmpdir:
         tmpdir = pathlib.Path(tmpdir)
         subprocess.run(["tar", "xf", str(raw_fw.resolve())], cwd=tmpdir, check=True)
+
         col = WiFiFWCollection(str(tmpdir.joinpath("firmware", "wifi")))
         pkg.add_files(sorted(col.files()))
+
         col = BluetoothFWCollection(str(tmpdir.joinpath("firmware", "bluetooth")))
         pkg.add_files(sorted(col.files()))
 
+        col = MultitouchFWCollection(str(tmpdir.joinpath("fud_firmware")))
+        pkg.add_files(sorted(col.files()))
+
     pkg.close()
 
     pkg.save_manifest(manifest)

src/stub.py

@@ -327,6 +327,9 @@ def collect_firmware(self, pkg):
         logging.info("Collecting Bluetooth firmware")
         col = asahi_firmware.bluetooth.BluetoothFWCollection("recovery/usr/share/firmware/bluetooth/")
         pkg.add_files(sorted(col.files()))
+        logging.info("Collecting Multitouch firmware")
+        col = asahi_firmware.multitouch.MultitouchFWCollection("fud_firmware/")
+        pkg.add_files(sorted(col.files()))
         logging.info("Making fallback firmware archive")
         subprocess.run(["tar", "czf", "all_firmware.tar.gz",
                         "fud_firmware",