mirror of https://github.com/commaai/panda.git
446 lines
13 KiB
Python
446 lines
13 KiB
Python
import binascii
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import ctypes
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import os
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import fcntl
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import math
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import time
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import struct
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import threading
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from contextlib import contextmanager
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from functools import reduce
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from collections.abc import Callable
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from .base import BaseHandle, BaseSTBootloaderHandle, TIMEOUT
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from .constants import McuType, MCU_TYPE_BY_IDCODE, USBPACKET_MAX_SIZE
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from .utils import logger
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try:
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import spidev
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except ImportError:
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spidev = None
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# Constants
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SYNC = 0x5A
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HACK = 0x79
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DACK = 0x85
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NACK = 0x1F
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CHECKSUM_START = 0xAB
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MIN_ACK_TIMEOUT_MS = 100
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MAX_XFER_RETRY_COUNT = 5
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XFER_SIZE = 0x40*31
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DEV_PATH = "/dev/spidev0.0"
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def crc8(data):
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crc = 0xFF # standard init value
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poly = 0xD5 # standard crc8: x8+x7+x6+x4+x2+1
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size = len(data)
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for i in range(size - 1, -1, -1):
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crc ^= data[i]
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for _ in range(8):
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if ((crc & 0x80) != 0):
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crc = ((crc << 1) ^ poly) & 0xFF
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else:
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crc <<= 1
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return crc
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class PandaSpiException(Exception):
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pass
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class PandaProtocolMismatch(PandaSpiException):
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pass
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class PandaSpiUnavailable(PandaSpiException):
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pass
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class PandaSpiNackResponse(PandaSpiException):
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pass
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class PandaSpiMissingAck(PandaSpiException):
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pass
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class PandaSpiBadChecksum(PandaSpiException):
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pass
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class PandaSpiTransferFailed(PandaSpiException):
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pass
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class PandaSpiTransfer(ctypes.Structure):
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_fields_ = [
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('rx_buf', ctypes.c_uint64),
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('tx_buf', ctypes.c_uint64),
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('tx_length', ctypes.c_uint32),
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('rx_length_max', ctypes.c_uint32),
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('timeout', ctypes.c_uint32),
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('endpoint', ctypes.c_uint8),
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('expect_disconnect', ctypes.c_uint8),
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]
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SPI_LOCK = threading.Lock()
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SPI_DEVICES = {}
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class SpiDevice:
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"""
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Provides locked, thread-safe access to a panda's SPI interface.
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"""
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# 50MHz is the max of the 845. older rev comma three
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# may not support the full 50MHz
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MAX_SPEED = 50000000
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def __init__(self, speed=MAX_SPEED):
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assert speed <= self.MAX_SPEED
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if not os.path.exists(DEV_PATH):
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raise PandaSpiUnavailable(f"SPI device not found: {DEV_PATH}")
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if spidev is None:
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raise PandaSpiUnavailable("spidev is not installed")
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with SPI_LOCK:
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if speed not in SPI_DEVICES:
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SPI_DEVICES[speed] = spidev.SpiDev() # pylint: disable=c-extension-no-member
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SPI_DEVICES[speed].open(0, 0)
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SPI_DEVICES[speed].max_speed_hz = speed
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self._spidev = SPI_DEVICES[speed]
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@contextmanager
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def acquire(self):
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try:
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SPI_LOCK.acquire()
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fcntl.flock(self._spidev, fcntl.LOCK_EX)
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yield self._spidev
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finally:
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fcntl.flock(self._spidev, fcntl.LOCK_UN)
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SPI_LOCK.release()
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def close(self):
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pass
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class PandaSpiHandle(BaseHandle):
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"""
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A class that mimics a libusb1 handle for panda SPI communications.
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"""
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PROTOCOL_VERSION = 2
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def __init__(self) -> None:
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self.dev = SpiDevice()
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self._transfer_raw: Callable[[SpiDevice, int, bytes, int, int, bool], bytes] = self._transfer_spidev
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if "KERN" in os.environ:
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self._transfer_raw = self._transfer_kernel_driver
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self.tx_buf = bytearray(1024)
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self.rx_buf = bytearray(1024)
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tx_buf_raw = ctypes.c_char.from_buffer(self.tx_buf)
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rx_buf_raw = ctypes.c_char.from_buffer(self.rx_buf)
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self.ioctl_data = PandaSpiTransfer()
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self.ioctl_data.tx_buf = ctypes.addressof(tx_buf_raw)
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self.ioctl_data.rx_buf = ctypes.addressof(rx_buf_raw)
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self.fileno = self.dev._spidev.fileno()
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# helpers
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def _calc_checksum(self, data: bytes) -> int:
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cksum = CHECKSUM_START
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for b in data:
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cksum ^= b
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return cksum
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def _wait_for_ack(self, spi, ack_val: int, timeout: int, tx: int, length: int = 1) -> bytes:
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timeout_s = max(MIN_ACK_TIMEOUT_MS, timeout) * 1e-3
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start = time.monotonic()
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while (timeout == 0) or ((time.monotonic() - start) < timeout_s):
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dat = spi.xfer2([tx, ] * length)
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if dat[0] == NACK:
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raise PandaSpiNackResponse
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elif dat[0] == ack_val:
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return bytes(dat)
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raise PandaSpiMissingAck
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def _transfer_spidev(self, spi, endpoint: int, data, timeout: int, max_rx_len: int = 1000, expect_disconnect: bool = False) -> bytes:
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max_rx_len = max(USBPACKET_MAX_SIZE, max_rx_len)
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logger.debug("- send header")
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packet = struct.pack("<BBHH", SYNC, endpoint, len(data), max_rx_len)
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packet += bytes([self._calc_checksum(packet), ])
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spi.xfer2(packet)
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logger.debug("- waiting for header ACK")
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self._wait_for_ack(spi, HACK, MIN_ACK_TIMEOUT_MS, 0x11)
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logger.debug("- sending data")
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packet = bytes([*data, self._calc_checksum(data)])
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spi.xfer2(packet)
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if expect_disconnect:
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logger.debug("- expecting disconnect, returning")
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return b""
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else:
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logger.debug("- waiting for data ACK")
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preread_len = USBPACKET_MAX_SIZE + 1 # read enough for a controlRead
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dat = self._wait_for_ack(spi, DACK, timeout, 0x13, length=3 + preread_len)
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# get response length, then response
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response_len = struct.unpack("<H", dat[1:3])[0]
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if response_len > max_rx_len:
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raise PandaSpiException(f"response length greater than max ({max_rx_len} {response_len})")
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# read rest
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remaining = (response_len + 1) - preread_len
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if remaining > 0:
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dat += bytes(spi.readbytes(remaining))
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dat = dat[:3 + response_len + 1]
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if self._calc_checksum(dat) != 0:
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raise PandaSpiBadChecksum
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return dat[3:-1]
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def _transfer_kernel_driver(self, spi, endpoint: int, data, timeout: int, max_rx_len: int = 1000, expect_disconnect: bool = False) -> bytes:
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import spidev2
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self.tx_buf[:len(data)] = data
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self.ioctl_data.endpoint = endpoint
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self.ioctl_data.tx_length = len(data)
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self.ioctl_data.rx_length_max = max_rx_len
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self.ioctl_data.expect_disconnect = int(expect_disconnect)
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# TODO: use our own ioctl request
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try:
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ret = fcntl.ioctl(self.fileno, spidev2.SPI_IOC_RD_LSB_FIRST, self.ioctl_data)
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except OSError as e:
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raise PandaSpiException from e
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if ret < 0:
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raise PandaSpiException(f"ioctl returned {ret}")
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return bytes(self.rx_buf[:ret])
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def _transfer(self, endpoint: int, data, timeout: int, max_rx_len: int = 1000, expect_disconnect: bool = False) -> bytes:
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logger.debug("starting transfer: endpoint=%d, max_rx_len=%d", endpoint, max_rx_len)
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logger.debug("==============================================")
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n = 0
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start_time = time.monotonic()
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exc = PandaSpiException()
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while (timeout == 0) or (time.monotonic() - start_time) < timeout*1e-3:
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n += 1
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logger.debug("\ntry #%d", n)
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with self.dev.acquire() as spi:
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try:
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return self._transfer_raw(spi, endpoint, data, timeout, max_rx_len, expect_disconnect)
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except PandaSpiException as e:
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exc = e
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logger.debug("SPI transfer failed, retrying", exc_info=True)
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raise exc
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def get_protocol_version(self) -> bytes:
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vers_str = b"VERSION"
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def _get_version(spi) -> bytes:
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spi.writebytes(vers_str)
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logger.debug("- waiting for echo")
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start = time.monotonic()
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while True:
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version_bytes = spi.readbytes(len(vers_str) + 2)
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if bytes(version_bytes).startswith(vers_str):
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break
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if (time.monotonic() - start) > 0.001:
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raise PandaSpiMissingAck
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rlen = struct.unpack("<H", bytes(version_bytes[-2:]))[0]
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if rlen > 1000:
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raise PandaSpiException("response length greater than max")
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# get response
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dat = spi.readbytes(rlen + 1)
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resp = dat[:-1]
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calculated_crc = crc8(bytes(version_bytes + resp))
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if calculated_crc != dat[-1]:
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raise PandaSpiBadChecksum
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return bytes(resp)
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exc = PandaSpiException()
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with self.dev.acquire() as spi:
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for _ in range(10):
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try:
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return _get_version(spi)
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except PandaSpiException as e:
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exc = e
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logger.debug("SPI get protocol version failed, retrying", exc_info=True)
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raise exc
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# libusb1 functions
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def close(self):
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self.dev.close()
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def controlWrite(self, request_type: int, request: int, value: int, index: int, data, timeout: int = TIMEOUT, expect_disconnect: bool = False):
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return self._transfer(0, struct.pack("<BHHH", request, value, index, 0), timeout, expect_disconnect=expect_disconnect)
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def controlRead(self, request_type: int, request: int, value: int, index: int, length: int, timeout: int = TIMEOUT):
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return self._transfer(0, struct.pack("<BHHH", request, value, index, length), timeout, max_rx_len=length)
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def bulkWrite(self, endpoint: int, data: bytes, timeout: int = TIMEOUT) -> int:
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for x in range(math.ceil(len(data) / XFER_SIZE)):
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self._transfer(endpoint, data[XFER_SIZE*x:XFER_SIZE*(x+1)], timeout)
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return len(data)
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def bulkRead(self, endpoint: int, length: int, timeout: int = TIMEOUT) -> bytes:
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ret = b""
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for _ in range(math.ceil(length / XFER_SIZE)):
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d = self._transfer(endpoint, [], timeout, max_rx_len=XFER_SIZE)
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ret += d
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if len(d) < XFER_SIZE:
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break
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return ret
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class STBootloaderSPIHandle(BaseSTBootloaderHandle):
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"""
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Implementation of the STM32 SPI bootloader protocol described in:
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https://www.st.com/resource/en/application_note/an4286-spi-protocol-used-in-the-stm32-bootloader-stmicroelectronics.pdf
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"""
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SYNC = 0x5A
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ACK = 0x79
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NACK = 0x1F
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def __init__(self):
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self.dev = SpiDevice(speed=1000000)
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# say hello
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try:
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with self.dev.acquire() as spi:
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spi.xfer([self.SYNC, ])
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try:
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self._get_ack(spi, 0.1)
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except (PandaSpiNackResponse, PandaSpiMissingAck):
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# NACK ok here, will only ACK the first time
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pass
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self._mcu_type = MCU_TYPE_BY_IDCODE[self.get_chip_id()]
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except PandaSpiException:
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raise PandaSpiException("failed to connect to panda") from None
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def _get_ack(self, spi, timeout=1.0):
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data = 0x00
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start_time = time.monotonic()
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while data not in (self.ACK, self.NACK) and (time.monotonic() - start_time < timeout):
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data = spi.xfer([0x00, ])[0]
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time.sleep(0)
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spi.xfer([self.ACK, ])
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if data == self.NACK:
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raise PandaSpiNackResponse
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elif data != self.ACK:
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raise PandaSpiMissingAck
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def _cmd_no_retry(self, cmd: int, data: list[bytes] | None = None, read_bytes: int = 0, predata=None) -> bytes:
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ret = b""
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with self.dev.acquire() as spi:
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# sync + command
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spi.xfer([self.SYNC, ])
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spi.xfer([cmd, cmd ^ 0xFF])
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self._get_ack(spi, timeout=0.01)
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# "predata" - for commands that send the first data without a checksum
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if predata is not None:
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spi.xfer(predata)
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self._get_ack(spi)
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# send data
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if data is not None:
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for d in data:
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if predata is not None:
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spi.xfer(d + self._checksum(predata + d))
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else:
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spi.xfer(d + self._checksum(d))
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self._get_ack(spi, timeout=20)
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# receive
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if read_bytes > 0:
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ret = spi.xfer([0x00, ]*(read_bytes + 1))[1:]
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if data is None or len(data) == 0:
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self._get_ack(spi)
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return bytes(ret)
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def _cmd(self, cmd: int, data: list[bytes] | None = None, read_bytes: int = 0, predata=None) -> bytes:
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exc = PandaSpiException()
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for n in range(MAX_XFER_RETRY_COUNT):
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try:
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return self._cmd_no_retry(cmd, data, read_bytes, predata)
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except PandaSpiException as e:
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exc = e
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logger.debug("SPI transfer failed, %d retries left", MAX_XFER_RETRY_COUNT - n - 1, exc_info=True)
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raise exc
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def _checksum(self, data: bytes) -> bytes:
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if len(data) == 1:
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ret = data[0] ^ 0xFF
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else:
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ret = reduce(lambda a, b: a ^ b, data)
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return bytes([ret, ])
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# *** Bootloader commands ***
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def read(self, address: int, length: int):
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data = [struct.pack('>I', address), struct.pack('B', length - 1)]
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return self._cmd(0x11, data=data, read_bytes=length)
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def get_bootloader_id(self):
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return self.read(0x1FF1E7FE, 1)
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def get_chip_id(self) -> int:
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r = self._cmd(0x02, read_bytes=3)
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if r[0] != 1: # response length - 1
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raise PandaSpiException("incorrect response length")
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return ((r[1] << 8) + r[2])
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def go_cmd(self, address: int) -> None:
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self._cmd(0x21, data=[struct.pack('>I', address), ])
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# *** helpers ***
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def get_uid(self):
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dat = self.read(McuType.H7.config.uid_address, 12)
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return binascii.hexlify(dat).decode()
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def erase_sector(self, sector: int):
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p = struct.pack('>H', 0) # number of sectors to erase
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d = struct.pack('>H', sector)
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self._cmd(0x44, data=[d, ], predata=p)
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# *** PandaDFU API ***
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def get_mcu_type(self):
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return self._mcu_type
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def clear_status(self):
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pass
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def close(self):
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self.dev.close()
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def program(self, address, dat):
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bs = 256 # max block size for writing to flash over SPI
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dat += b"\xFF" * ((bs - len(dat)) % bs)
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for i in range(len(dat) // bs):
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block = dat[i * bs:(i + 1) * bs]
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self._cmd(0x31, data=[
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struct.pack('>I', address + i*bs),
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bytes([len(block) - 1]) + block,
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])
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def jump(self, address):
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self.go_cmd(self._mcu_type.config.bootstub_address)
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