2 files changed, 45 insertions, 0 deletions
diff --git a/tests/ports/stm32_hardware/dma_alignment.py b/tests/ports/stm32_hardware/dma_alignment.py
new file mode 100644
index 000000000..1836b25d8
--- /dev/null
+++ b/tests/ports/stm32_hardware/dma_alignment.py
@@ -0,0 +1,43 @@
+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"))
diff --git a/tests/ports/stm32_hardware/dma_alignment.py.exp b/tests/ports/stm32_hardware/dma_alignment.py.exp
new file mode 100644
index 000000000..e890e0081
--- /dev/null
+++ b/tests/ports/stm32_hardware/dma_alignment.py.exp
@@ -0,0 +1,2 @@
+Variable offset fixed length OK
+Variable offset and lengths OK