tests: gadget0: test for unaligned buffer read/writes.

This currently fails on stm32F072, which is expected but not normal.
See GH issues #401 , #461

tests/gadget-zero/test_gadget0.py

@@ -318,3 +318,54 @@ class TestControlTransfer_Reads(unittest.TestCase):
         self.assertEqual(len(q), 10, "In this case, should have gotten wLen back")
 
 
+class TestUnaligned(unittest.TestCase):
+    """
+    M0 and M0+ cores don't support unaligned memory accesses. These test
+    how the stack behaves with aligned vs unaligned buffers.
+    https://github.com/libopencm3/libopencm3/issues/401
+    https://github.com/libopencm3/libopencm3/issues/461
+    """
+
+    def setUp(self):
+        self.dev = usb.core.find(idVendor=0xcafe, idProduct=0xcafe, custom_match=find_by_serial(DUT_SERIAL))
+        self.assertIsNotNone(self.dev, "Couldn't find locm3 gadget0 device")
+
+        self.cfg = uu.find_descriptor(self.dev, bConfigurationValue=2)
+        self.assertIsNotNone(self.cfg, "Config 2 should exist")
+        self.dev.set_configuration(self.cfg);
+        self.req = uu.CTRL_OUT | uu.CTRL_TYPE_VENDOR | uu.CTRL_RECIPIENT_INTERFACE
+        self.intf = self.cfg[(0, 0)]
+        # heh, kinda gross...
+        self.ep_out = [ep for ep in self.intf if uu.endpoint_direction(ep.bEndpointAddress) == uu.ENDPOINT_OUT][0]
+        self.ep_in = [ep for ep in self.intf if uu.endpoint_direction(ep.bEndpointAddress) == uu.ENDPOINT_IN][0]
+
+    def tearDown(self):
+        uu.dispose_resources(self.dev)
+
+    def set_unaligned(self):
+        # GZ_REQ_SET_UNALIGNED
+        x = self.dev.ctrl_transfer(self.req, 4, 0, 0)
+
+    def set_aligned(self):
+        # GZ_REQ_SET_ALIGNED
+        x = self.dev.ctrl_transfer(self.req, 3, 0, 0)
+
+    def do_readwrite(self):
+        """
+        transfer garbage data to/from bulk EP; alignment issues will hardfault the target
+        """
+        data = [x for x in range(int(self.ep_out.wMaxPacketSize / 2))]
+        written = self.dev.write(self.ep_out, data)
+        self.assertEqual(written, len(data), "Should have written all bytes plz")
+
+        read_size = self.ep_in.wMaxPacketSize * 10
+        data = self.dev.read(self.ep_in, read_size)
+        self.assertEqual(len(data), read_size, "Should have read as much as we asked for")
+
+    def test_aligned(self):
+        self.set_aligned()
+        self.do_readwrite()
+
+    def test_unaligned(self):
+        self.set_unaligned()
+        self.do_readwrite()

tests/gadget-zero/usb-gadget0.c

@@ -45,6 +45,8 @@
  */
 #define GZ_REQ_SET_PATTERN	1
 #define GZ_REQ_PRODUCE		2
+#define GZ_REQ_SET_ALIGNED	3
+#define GZ_REQ_SET_UNALIGNED	4
 #define INTEL_COMPLIANCE_WRITE 0x5b
 #define INTEL_COMPLIANCE_READ 0x5c
 
@@ -177,42 +179,60 @@ static usbd_device *our_dev;
 static struct {
 	uint8_t pattern;
 	int pattern_counter;
+	int test_unaligned;	/* If 0 (default), use 16-bit aligned buffers. This should not be declared as bool */
 } state = {
 	.pattern = 0,
 	.pattern_counter = 0,
+	.test_unaligned = 0,
 };
 
 static void gadget0_ss_out_cb(usbd_device *usbd_dev, uint8_t ep)
 {
 	(void) ep;
+	uint16_t x;
 	/* TODO - if you're really keen, perf test this. tiva implies it matters */
 	/* char buf[64] __attribute__ ((aligned(4))); */
-	char buf[BULK_EP_MAXPACKET];
+	uint8_t buf[BULK_EP_MAXPACKET + 1] __attribute__ ((aligned(2)));
+	uint8_t *dest;
+
 	trace_send_blocking8(0, 'O');
-	uint16_t x = usbd_ep_read_packet(usbd_dev, ep, buf, sizeof(buf));
+	if (state.test_unaligned) {
+		dest = buf + 1;
+	} else {
+		dest = buf;
+	}
+	x = usbd_ep_read_packet(usbd_dev, ep, dest, BULK_EP_MAXPACKET);
 	trace_send_blocking8(1, x);
 }
 
 static void gadget0_ss_in_cb(usbd_device *usbd_dev, uint8_t ep)
 {
 	(void) usbd_dev;
+	uint8_t buf[BULK_EP_MAXPACKET + 1] __attribute__ ((aligned(2)));
+	uint8_t *src;
+
 	trace_send_blocking8(0, 'I');
-	uint8_t buf[BULK_EP_MAXPACKET];
+	if (state.test_unaligned) {
+		src = buf + 1;
+	} else {
+		src = buf;
+	}
+
 	switch (state.pattern) {
 	case 0:
-		memset(buf, 0, sizeof(buf));
+		memset(src, 0, BULK_EP_MAXPACKET);
 		break;
 	case 1:
-		for (unsigned i = 0; i < sizeof(buf); i++) {
+		for (unsigned i = 0; i < BULK_EP_MAXPACKET; i++) {
-			buf[i] = state.pattern_counter++ % 63;
+			src[i] = state.pattern_counter++ % 63;
 		}
 		break;
 	}
 
-	uint16_t x = usbd_ep_write_packet(usbd_dev, ep, buf, sizeof(buf));
+	uint16_t x = usbd_ep_write_packet(usbd_dev, ep, src, BULK_EP_MAXPACKET);
 	/* As we are calling write in the callback, this should never fail */
 	trace_send_blocking8(2, x);
-	if (x != sizeof(buf)) {
+	if (x != BULK_EP_MAXPACKET) {
 		ER_DPRINTF("failed to write?: %d\n", x);
 	}
 	/*assert(x == sizeof(buf));*/
@@ -256,6 +276,12 @@ static int gadget0_control_request(usbd_device *usbd_dev,
 	case INTEL_COMPLIANCE_READ:
 		ER_DPRINTF("unimplemented!");
 		return USBD_REQ_NOTSUPP;
+	case GZ_REQ_SET_UNALIGNED:
+		state.test_unaligned = 1;
+		return USBD_REQ_HANDLED;
+	case GZ_REQ_SET_ALIGNED:
+		state.test_unaligned = 0;
+		return USBD_REQ_HANDLED;
 	case GZ_REQ_PRODUCE:
 		ER_DPRINTF("fake loopback of %d\n", req->wValue);
 		if (req->wValue > sizeof(usbd_control_buffer)) {
@@ -280,6 +306,7 @@ static void gadget0_set_config(usbd_device *usbd_dev, uint16_t wValue)
 	ER_DPRINTF("set cfg %d\n", wValue);
 	switch (wValue) {
 	case GZ_CFG_SOURCESINK:
+		state.test_unaligned = 0;
 		usbd_ep_setup(usbd_dev, 0x01, USB_ENDPOINT_ATTR_BULK, BULK_EP_MAXPACKET,
 			gadget0_ss_out_cb);
 		usbd_ep_setup(usbd_dev, 0x82, USB_ENDPOINT_ATTR_BULK, BULK_EP_MAXPACKET,