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

[Mathias Nyman <mathias.nyman@linux.intel.com>]

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 <mathias.nyman@linux.intel.com>
---
 drivers/usb/misc/usbtest.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/drivers/usb/misc/usbtest.c b/drivers/usb/misc/usbtest.c
index aedc9a7..2c9a15b 100644
--- a/drivers/usb/misc/usbtest.c
+++ b/drivers/usb/misc/usbtest.c
@@ -1710,6 +1710,35 @@ static int test_halt(struct usbtest_dev *tdev, int ep, struct urb *urb)
 	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;
@@ -1742,6 +1771,36 @@ static int halt_simple(struct usbtest_dev *dev)
 	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);
+
+	/*
+	 * 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 max packet length packes and one zero packet.
+	 */
+
+	if (udev->speed == USB_SPEED_SUPER)
+		urb = simple_alloc_urb(udev, 0, 2048, 0);
+	else
+		urb = simple_alloc_urb(udev, 0, 1024, 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;
+}
+
 /*-------------------------------------------------------------------------*/
 
 /* Control OUT tests use the vendor control requests from Intel's
@@ -2524,6 +2583,20 @@ usbtest_do_ioctl(struct usb_interface *intf, struct usbtest_param_32 *param)
 		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 && dev->in_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--; /* NOP */)
+			retval = toggle_sync_simple(dev);
+
+		if (retval)
+			ERROR(dev, "toggle sync failed, iterations left %d\n",
+			      i);
+		break;
 	}
 	return retval;
 }