ipxe/src/drivers/bus/cdc.c

/*
 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

FILE_LICENCE ( GPL2_OR_LATER );

#include <stddef.h>
#include <ipxe/usb.h>
#include <ipxe/cdc.h>

/** @file
 *
 * USB Communications Device Class (CDC)
 *
 */

/**
 * Locate CDC union functional descriptor
 *
 * @v config		Configuration descriptor
 * @v interface		Interface descriptor
 * @ret desc		Union functional descriptor, or NULL if not found
 */
struct cdc_union_descriptor *
cdc_union_descriptor ( struct usb_configuration_descriptor *config,
		       struct usb_interface_descriptor *interface ) {
	struct cdc_union_descriptor *desc;

	for_each_interface_descriptor ( desc, config, interface ) {
		if ( ( desc->header.type == USB_CS_INTERFACE_DESCRIPTOR ) &&
		     ( desc->subtype == CDC_SUBTYPE_UNION ) )
			return desc;
	}
	return NULL;
}