[PATCH] USB: usbtest, autoconfigure from descriptors

Not all gadget controllers support ep2in-bulk and ep2out-bulk,
unlike the EZ-USB (non-FX2) devices or the net2280.

So this patch teaches "usbtest" how to look at the descriptors
it's given, and use the appropriate endpoints.  This helps
support Linux test devices using hardware like the pxa2xx UDC,
and other controllers.

drivers/usb/misc/usbtest.c

@@ -47,6 +47,7 @@ struct usbtest_info {
 	const char		*name;
 	u8			ep_in;		/* bulk/intr source */
 	u8			ep_out;		/* bulk/intr sink */
+	unsigned		autoconf : 1;
 	int			alt;
 };
 
@@ -78,6 +79,61 @@ static struct usb_device *testdev_to_usbdev (struct usbtest_dev *test)
 
 /*-------------------------------------------------------------------------*/
 
+static int
+get_endpoints (struct usbtest_dev *dev, struct usb_interface *intf)
+{
+	int				tmp;
+	struct usb_host_interface	*alt;
+	struct usb_host_endpoint	*in, *out;
+	struct usb_device		*udev;
+
+	for (tmp = 0; tmp < intf->max_altsetting; tmp++) {
+		unsigned	ep;
+
+		in = out = 0;
+		alt = intf->altsetting + tmp;
+
+		/* take the first altsetting with in-bulk + out-bulk;
+		 * ignore other endpoints and altsetttings.
+		 */
+		for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
+			struct usb_host_endpoint	*e;
+
+			e = alt->endpoint + ep;
+			if (e->desc.bmAttributes != USB_ENDPOINT_XFER_BULK)
+				continue;
+			if (e->desc.bEndpointAddress & USB_DIR_IN) {
+				if (!in)
+					in = e;
+			} else {
+				if (!out)
+					out = e;
+			}
+			if (in && out)
+				goto found;
+		}
+	}
+	return -EINVAL;
+
+found:
+	udev = testdev_to_usbdev (dev);
+	if (alt->desc.bAlternateSetting != 0) {
+		tmp = usb_set_interface (udev,
+				alt->desc.bInterfaceNumber,
+				alt->desc.bAlternateSetting);
+		if (tmp < 0)
+			return tmp;
+	}
+
+	dev->in_pipe = usb_rcvbulkpipe (udev,
+			in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
+	dev->out_pipe = usb_sndbulkpipe (udev,
+			out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
+	return 0;
+}
+
+/*-------------------------------------------------------------------------*/
+
 /* Support for testing basic non-queued I/O streams.
  *
  * These just package urbs as requests that can be easily canceled.
@@ -1275,15 +1331,27 @@ usbtest_probe (struct usb_interface *intf, const struct usb_device_id *id)
 			wtest = " intr-out";
 		}
 	} else {
-		if (info->ep_in) {
-			dev->in_pipe = usb_rcvbulkpipe (udev, info->ep_in);
-			rtest = " bulk-in";
+		if (info->autoconf) {
+			int status;
+
+			status = get_endpoints (dev, intf);
+			if (status < 0) {
+				dbg ("couldn't get endpoints, %d\n", status);
+				return status;
 			}
-		if (info->ep_out) {
-			dev->out_pipe = usb_sndbulkpipe (udev, info->ep_out);
+		} else {
+			if (info->ep_in)
+				dev->in_pipe = usb_rcvbulkpipe (udev,
+							info->ep_in);
+			if (info->ep_out)
+				dev->out_pipe = usb_sndbulkpipe (udev,
+							info->ep_out);
+		}
+		if (dev->in_pipe)
+			rtest = " bulk-in";
+		if (dev->out_pipe)
 			wtest = " bulk-out";
 	}
-	}
 
 	usb_set_intfdata (intf, dev);
 	info ("%s at %s ... %s speed {control%s%s} tests",
@@ -1336,11 +1404,6 @@ static struct usbtest_info ez2_info = {
 };
 
 /* ezusb family device with dedicated usb test firmware,
- * or a peripheral running Linux and 'zero.c' test firmware.
- *
- * FIXME usbtest should read the descriptors, since compatible
- * test firmware might run on hardware (pxa250 for one) that
- * can't configure an ep2in-bulk.
  */
 static struct usbtest_info fw_info = {
 	.name		= "usb test device",
@@ -1349,10 +1412,20 @@ static struct usbtest_info fw_info = {
 	.alt		= 0,
 };
 
+/* peripheral running Linux and 'zero.c' test firmware, or
+ * its user-mode cousin. different versions of this use
+ * different hardware with the same vendor/product codes.
+ * host side MUST rely on the endpoint descriptors.
+ */
+static struct usbtest_info gz_info = {
+	.name		= "Linux gadget zero",
+	.autoconf	= 1,
+	.alt		= 0,
+};
+
 static struct usbtest_info um_info = {
-	.name		= "user mode test driver",
-	.ep_in		= 7,
-	.ep_out		= 3,
+	.name		= "Linux user mode test driver",
+	.autoconf	= 1,
 	.alt		= -1,
 };
 
@@ -1418,7 +1491,7 @@ static struct usb_device_id id_table [] = {
 
 	/* "Gadget Zero" firmware runs under Linux */
 	{ USB_DEVICE (0x0525, 0xa4a0),
-		.driver_info = (unsigned long) &fw_info,
+		.driver_info = (unsigned long) &gz_info,
 		},
 
 	/* so does a user-mode variant */