usb: usbtest: Add TEST 29, toggle sync, Clear toggle between bulk writes

Clear Feature Endpoint Halt should reset the data toggle even if the
endpoint isn't halted. Host should manage to clear the host side data
toggle to keep in sync with the device.

Test by sending a "3 data packet URB" before and after clearing the halt.
this should create a toggle sequence with two consecutive DATA0 packets.

A successful test sequence looks like this
ClearFeature(ENDPOINT_HALT) - initial toggle clear
DATA0 (max packet sized)
DATA1 (max packet sized)
DATA0 (zero length packet)
ClearFeature(ENDPOINT_HALT) - resets toggle
DATA0 (max packet sized), if clear halt fails then toggle is DATA1
DATA1 (max packet sized)
DATA0 (zero length packet)

Signed-off-by: Mathias Nyman <[e-mail]>
Acked-by: Alan Stern <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/misc/usbtest.c

···
 	return 0;
 }
 
+static int test_toggle_sync(struct usbtest_dev *tdev, int ep, struct urb *urb)
+{
+	int	retval;
+
+	/* clear initial data toggle to DATA0 */
+	retval = usb_clear_halt(urb->dev, urb->pipe);
+	if (retval < 0) {
+		ERROR(tdev, "ep %02x couldn't clear halt, %d\n", ep, retval);
+		return retval;
+	}
+
+	/* transfer 3 data packets, should be DATA0, DATA1, DATA0 */
+	retval = simple_io(tdev, urb, 1, 0, 0, __func__);
+	if (retval != 0)
+		return -EINVAL;
+
+	/* clear halt resets device side data toggle, host should react to it */
+	retval = usb_clear_halt(urb->dev, urb->pipe);
+	if (retval < 0) {
+		ERROR(tdev, "ep %02x couldn't clear halt, %d\n", ep, retval);
+		return retval;
+	}
+
+	/* host should use DATA0 again after clear halt */
+	retval = simple_io(tdev, urb, 1, 0, 0, __func__);
+
+	return retval;
+}
+
 static int halt_simple(struct usbtest_dev *dev)
 {
 	int			ep;
···
 		retval = test_halt(dev, ep, urb);
 	}
 done:
+	simple_free_urb(urb);
+	return retval;
+}
+
+static int toggle_sync_simple(struct usbtest_dev *dev)
+{
+	int			ep;
+	int			retval = 0;
+	struct urb		*urb;
+	struct usb_device	*udev = testdev_to_usbdev(dev);
+	unsigned		maxp = get_maxpacket(udev, dev->out_pipe);
+
+	/*
+	 * Create a URB that causes a transfer of uneven amount of data packets
+	 * This way the clear toggle has an impact on the data toggle sequence.
+	 * Use 2 maxpacket length packets and one zero packet.
+	 */
+	urb = simple_alloc_urb(udev, 0,  2 * maxp, 0);
+	if (urb == NULL)
+		return -ENOMEM;
+
+	urb->transfer_flags |= URB_ZERO_PACKET;
+
+	ep = usb_pipeendpoint(dev->out_pipe);
+	urb->pipe = dev->out_pipe;
+	retval = test_toggle_sync(dev, ep, urb);
+
 	simple_free_urb(urb);
 	return retval;
 }
···
 			param->sglen * param->length) / (1024 * 1024));
 		retval = test_queue(dev, param,
 				dev->in_pipe, NULL, 0);
+		break;
+	/* Test data Toggle/seq_nr clear between bulk out transfers */
+	case 29:
+		if (dev->out_pipe == 0)
+			break;
+		retval = 0;
+		dev_info(&intf->dev, "TEST 29: Clear toggle between bulk writes %d times\n",
+				param->iterations);
+		for (i = param->iterations; retval == 0 && i > 0; --i)
+			retval = toggle_sync_simple(dev);
+
+		if (retval)
+			ERROR(dev, "toggle sync failed, iterations left %d\n",
+			      i);
 		break;
 	}
 	return retval;