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python lib: add SPI ACK timeout (#1199)

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* python lib: add SPI ACK timeout

* fix that

Co-authored-by: Comma Device <device@comma.ai>
This commit is contained in:
Adeeb Shihadeh
2022-12-20 22:07:24 -08:00
committed by GitHub
parent 345147fe2b
commit 5486eb3845
1 changed files with 38 additions and 20 deletions
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58
python/spi.py
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@@ -1,4 +1,5 @@
import math
import time
import struct
import spidev
import logging
@@ -12,10 +13,27 @@ DACK = 0x85
NACK = 0x1F
CHECKSUM_START = 0xAB
MAX_RETRY_COUNT = 5
ACK_TIMEOUT_SECONDS = 0.5
MAX_XFER_RETRY_COUNT = 5
USB_MAX_SIZE = 0x40
class PandaSpiException(Exception):
pass
class PandaSpiNackResponse(PandaSpiException):
pass
class PandaSpiMissingAck(PandaSpiException):
pass
class PandaSpiBadChecksum(PandaSpiException):
pass
class PandaSpiTransferFailed(PandaSpiException):
pass
# This mimics the handle given by libusb1 for easy interoperability
class SpiHandle:
def __init__(self):
@@ -31,11 +49,22 @@ class SpiHandle:
cksum ^= b
return cksum
def _wait_for_ack(self, ack_val: int) -> None:
start = time.monotonic()
while (time.monotonic() - start) < ACK_TIMEOUT_SECONDS:
dat = self.spi.xfer2(b"\x12")[0]
if dat == NACK:
raise PandaSpiNackResponse
elif dat == ack_val:
return
raise PandaSpiMissingAck
def _transfer(self, endpoint: int, data, max_rx_len: int = 1000) -> bytes:
logging.debug("starting transfer: endpoint=%d, max_rx_len=%d", endpoint, max_rx_len)
logging.debug("==============================================")
for n in range(MAX_RETRY_COUNT):
for n in range(MAX_XFER_RETRY_COUNT):
logging.debug("\ntry #%d", n+1)
try:
logging.debug("- send header")
@@ -43,27 +72,16 @@ class SpiHandle:
packet += bytes([reduce(lambda x, y: x^y, packet) ^ CHECKSUM_START])
self.spi.xfer2(packet)
logging.debug("- waiting for ACK")
# TODO: add timeout?
dat = b"\x00"
while dat[0] not in [HACK, NACK]:
dat = self.spi.xfer2(b"\x12")
if dat[0] == NACK:
raise Exception("Got NACK response for header")
logging.debug("- waiting for header ACK")
self._wait_for_ack(HACK)
# send data
logging.debug("- sending data")
packet = bytes([*data, self._calc_checksum(data)])
self.spi.xfer2(packet)
logging.debug("- waiting for ACK")
dat = b"\x00"
while dat[0] not in [DACK, NACK]:
dat = self.spi.xfer2(b"\xab")
if dat[0] == NACK:
raise Exception("Got NACK response for data")
logging.debug("- waiting for data ACK")
self._wait_for_ack(DACK)
# get response length, then response
response_len_bytes = bytes(self.spi.xfer2(b"\x00" * 2))
@@ -72,12 +90,12 @@ class SpiHandle:
logging.debug("- receiving response")
dat = bytes(self.spi.xfer2(b"\x00" * (response_len + 1)))
if self._calc_checksum([DACK, *response_len_bytes, *dat]) != 0:
raise Exception("SPI got bad checksum")
raise PandaSpiBadChecksum
return dat[:-1]
except Exception:
except PandaSpiException:
logging.exception("SPI transfer failed, %d retries left", n)
raise Exception(f"SPI transaction failed {MAX_RETRY_COUNT} times")
raise PandaSpiTransferFailed(f"SPI transaction failed {MAX_XFER_RETRY_COUNT} times")
# libusb1 functions
def close(self):