micropython/tests/ports/stm32_hardware/dma_alignment.py

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1.4 KiB
Python

from machine import SPI
# Regression test for DMA for DCache coherency bugs with cache line
# written originally for https://github.com/micropython/micropython/issues/13471
# IMPORTANT: This test requires SPI2 MISO (pin Y8 on Pyboard D) to be connected to GND
SPI_NUM = 2
spi = SPI(SPI_NUM, baudrate=5_000_000)
buf = bytearray(1024)
ok = True
for offs in range(0, len(buf)):
v = memoryview(buf)[offs : offs + 128]
spi.readinto(v, 0xFF)
if not all(b == 0x00 for b in v):
print(offs, v.hex())
ok = False
print("Variable offset fixed length " + ("OK" if ok else "FAIL"))
# this takes around 30s to run, so skipped if already failing
if ok:
for op_len in range(1, 66):
wr = b"\xFF" * op_len
for offs in range(1, len(buf) - op_len - 1):
# Place some "sentinel" values before and after the DMA buffer
before = offs & 0xFF
after = (~offs) & 0xFF
buf[offs - 1] = before
buf[offs + op_len] = after
v = memoryview(buf)[offs : offs + op_len]
spi.write_readinto(wr, v)
if (
not all(b == 0x00 for b in v)
or buf[offs - 1] != before
or buf[offs + op_len] != after
):
print(v.hex())
print(hex(op_len), hex(offs), hex(buf[offs - 1]), hex(buf[offs + op_len]))
ok = False
print("Variable offset and lengths " + ("OK" if ok else "FAIL"))