PandaDFU: SPI support (#1270)

* PandaDFU: SPI support

* get mcu type

* program bootstub

* little cleanup

* more cleanup

* connect by dfu serial

* time to remove that

* none

* fix linter

* little more

* catch

---------

Co-authored-by: Comma Device <device@comma.ai>

python/spi.py

@@ -1,3 +1,4 @@
+import binascii
 import os
 import fcntl
 import math
@@ -7,9 +8,10 @@ import logging
 import threading
 from contextlib import contextmanager
 from functools import reduce
-from typing import List
+from typing import List, Optional
 
-from .base import BaseHandle
+from .base import BaseHandle, BaseSTBootloaderHandle
+from .constants import McuType, MCU_TYPE_BY_IDCODE
 
 try:
   import spidev
@@ -172,3 +174,136 @@ class PandaSpiHandle(BaseHandle):
         if len(d) < USB_MAX_SIZE:
           break
     return bytes(ret)
+
+
+class STBootloaderSPIHandle(BaseSTBootloaderHandle):
+  """
+    Implementation of the STM32 SPI bootloader protocol described in:
+    https://www.st.com/resource/en/application_note/an4286-spi-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf
+  """
+
+  SYNC = 0x5A
+  ACK = 0x79
+  NACK = 0x1F
+
+  def __init__(self):
+    self.dev = SpiDevice(speed=1000000)
+
+    # say hello
+    try:
+      with self.dev.acquire() as spi:
+        spi.xfer([self.SYNC, ])
+        try:
+          self._get_ack(spi)
+        except PandaSpiNackResponse:
+          # NACK ok here, will only ACK the first time
+          pass
+
+      self._mcu_type = MCU_TYPE_BY_IDCODE[self.get_chip_id()]
+    except PandaSpiException:
+      raise PandaSpiException("failed to connect to panda")  # pylint: disable=W0707
+
+  def _get_ack(self, spi, timeout=1.0):
+    data = 0x00
+    start_time = time.monotonic()
+    while data not in (self.ACK, self.NACK) and (time.monotonic() - start_time < timeout):
+      data = spi.xfer([0x00, ])[0]
+      time.sleep(0.001)
+    spi.xfer([self.ACK, ])
+
+    if data == self.NACK:
+      raise PandaSpiNackResponse
+    elif data != self.ACK:
+      raise PandaSpiMissingAck
+
+  def _cmd(self, cmd: int, data: Optional[List[bytes]] = None, read_bytes: int = 0, predata=None) -> bytes:
+    ret = b""
+    with self.dev.acquire() as spi:
+      # sync + command
+      spi.xfer([self.SYNC, ])
+      spi.xfer([cmd, cmd ^ 0xFF])
+      self._get_ack(spi)
+
+      # "predata" - for commands that send the first data without a checksum
+      if predata is not None:
+        spi.xfer(predata)
+        self._get_ack(spi)
+
+      # send data
+      if data is not None:
+        for d in data:
+          if predata is not None:
+            spi.xfer(d + self._checksum(predata + d))
+          else:
+            spi.xfer(d + self._checksum(d))
+          self._get_ack(spi, timeout=20)
+
+      # receive
+      if read_bytes > 0:
+        ret = spi.xfer([0x00, ]*(read_bytes + 1))[1:]
+        if data is None or len(data) == 0:
+          self._get_ack(spi)
+
+    return bytes(ret)
+
+  def _checksum(self, data: bytes) -> bytes:
+    if len(data) == 1:
+      ret = data[0] ^ 0xFF
+    else:
+      ret = reduce(lambda a, b: a ^ b, data)
+    return bytes([ret, ])
+
+  # *** Bootloader commands ***
+
+  def read(self, address: int, length: int):
+    data = [struct.pack('>I', address), struct.pack('B', length - 1)]
+    return self._cmd(0x11, data=data, read_bytes=length)
+
+  def get_chip_id(self) -> int:
+    r = self._cmd(0x02, read_bytes=3)
+    assert r[0] == 1  # response length - 1
+    return ((r[1] << 8) + r[2])
+
+  def go_cmd(self, address: int) -> None:
+    self._cmd(0x21, data=[struct.pack('>I', address), ])
+
+  # *** helpers ***
+
+  def get_uid(self):
+    dat = self.read(McuType.H7.config.uid_address, 12)
+    return binascii.hexlify(dat).decode()
+
+  def erase_sector(self, sector: int):
+    p = struct.pack('>H', 0)  # number of sectors to erase
+    d = struct.pack('>H', sector)
+    self._cmd(0x44, data=[d, ], predata=p)
+
+  # *** PandaDFU API ***
+
+  def erase_app(self):
+    self.erase_sector(1)
+
+  def erase_bootstub(self):
+    self.erase_sector(0)
+
+  def get_mcu_type(self):
+    return self._mcu_type
+
+  def clear_status(self):
+    pass
+
+  def close(self):
+    self.dev.close()
+
+  def program(self, address, dat):
+    bs = 256  # max block size for writing to flash over SPI
+    dat += b"\xFF" * ((bs - len(dat)) % bs)
+    for i in range(0, len(dat) // bs):
+      block = dat[i * bs:(i + 1) * bs]
+      self._cmd(0x31, data=[
+        struct.pack('>I', address + i*bs),
+        bytes([len(block) - 1]) + block,
+      ])
+
+  def jump(self, address):
+    self.go_cmd(self._mcu_type.config.bootstub_address)