fel: Detect FEL mode bulk transfer endpoint addresses at startup

FEL mode on the A80 changed the bulk transfer endpoint.

Let the fel utility look for the endpoint addresses instead
of hard-coding them.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Henrik Nordstrom <henrik@henriknordstrom.net>

fel.c

@@ -44,8 +44,8 @@ struct  aw_usb_request {
 static const int AW_USB_READ = 0x11;
 static const int AW_USB_WRITE = 0x12;
 
-static const int AW_USB_FEL_BULK_EP_OUT=0x01;
-static const int AW_USB_FEL_BULK_EP_IN=0x82;
+static int AW_USB_FEL_BULK_EP_OUT;
+static int AW_USB_FEL_BULK_EP_IN;
 static int timeout = 60000;
 
 void usb_bulk_send(libusb_device_handle *usb, int ep, const void *data, int length)
@@ -285,6 +285,46 @@ void aw_fel_fill(libusb_device_handle *usb, uint32_t offset, size_t size, unsign
 	aw_fel_write(usb, buf, offset, size);
 }
 
+static int aw_fel_get_endpoint(libusb_device_handle *usb)
+{
+	struct libusb_device *dev = libusb_get_device(usb);
+	struct libusb_config_descriptor *config;
+	int if_idx, set_idx, ep_idx, ret;
+
+	ret = libusb_get_active_config_descriptor(dev, &config);
+	if (ret)
+		return ret;
+
+	for (if_idx = 0; if_idx < config->bNumInterfaces; if_idx++) {
+		const struct libusb_interface *iface = config->interface + if_idx;
+
+		for (set_idx = 0; set_idx < iface->num_altsetting; set_idx++) {
+			const struct libusb_interface_descriptor *setting =
+				iface->altsetting + set_idx;
+
+			for (ep_idx = 0; ep_idx < setting->bNumEndpoints; ep_idx++) {
+				const struct libusb_endpoint_descriptor *ep =
+					setting->endpoint + ep_idx;
+
+				// Test for bulk transfer endpoint
+				if ((ep->bmAttributes & LIBUSB_TRANSFER_TYPE_MASK) !=
+						LIBUSB_TRANSFER_TYPE_BULK)
+					continue;
+
+				if ((ep->bEndpointAddress & LIBUSB_ENDPOINT_DIR_MASK) ==
+						LIBUSB_ENDPOINT_IN)
+					AW_USB_FEL_BULK_EP_IN = ep->bEndpointAddress;
+				else
+					AW_USB_FEL_BULK_EP_OUT = ep->bEndpointAddress;
+			}
+		}
+	}
+
+	libusb_free_config_descriptor(config);
+
+	return 0;
+}
+
 int main(int argc, char **argv)
 {
 	int rc;
@@ -329,6 +369,11 @@ int main(int argc, char **argv)
 #endif
 	assert(rc == 0);
 
+	if (aw_fel_get_endpoint(handle)) {
+		fprintf(stderr, "ERROR: Failed to get FEL mode endpoint addresses!\n");
+		exit(1);
+	}
+
 	while (argc > 1 ) {
 		int skip = 1;
 		if (strncmp(argv[1], "hex", 3) == 0 && argc > 3) {