path: root/drivers/usb/gadget/composite.c

/*
 * composite.c - infrastructure for Composite USB Gadgets
 *
 * Copyright (C) 2006-2008 David Brownell
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* #define VERBOSE_DEBUG */

#include <linux/kallsyms.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>

#include <linux/usb/composite.h>


/*
 * The code in this file is utility code, used to build a gadget driver
 * from one or more "function" drivers, one or more "configuration"
 * objects, and a "usb_composite_driver" by gluing them together along
 * with the relevant device-wide data.
 */

/* big enough to hold our biggest descriptor */
#define USB_BUFSIZ	512

static struct usb_composite_driver *composite;

/* Some systems will need runtime overrides for the  product identifers
 * published in the device descriptor, either numbers or strings or both.
 * String parameters are in UTF-8 (superset of ASCII's 7 bit characters).
 */

static ushort idVendor;
module_param(idVendor, ushort, 0);
MODULE_PARM_DESC(idVendor, "USB Vendor ID");

static ushort idProduct;
module_param(idProduct, ushort, 0);
MODULE_PARM_DESC(idProduct, "USB Product ID");

static ushort bcdDevice;
module_param(bcdDevice, ushort, 0);
MODULE_PARM_DESC(bcdDevice, "USB Device version (BCD)");

static char *iManufacturer;
module_param(iManufacturer, charp, 0);
MODULE_PARM_DESC(iManufacturer, "USB Manufacturer string");

static char *iProduct;
module_param(iProduct, charp, 0);
MODULE_PARM_DESC(iProduct, "USB Product string");

static char *iSerialNumber;
module_param(iSerialNumber, charp, 0);
MODULE_PARM_DESC(iSerialNumber, "SerialNumber string");

/*-------------------------------------------------------------------------*/

/**
 * usb_add_function() - add a function to a configuration
 * @config: the configuration
 * @function: the function being added
 * Context: single threaded during gadget setup
 *
 * After initialization, each configuration must have one or more
 * functions added to it.  Adding a function involves calling its @bind()
 * method to allocate resources such as interface and string identifiers
 * and endpoints.
 *
 * This function returns the value of the function's bind(), which is
 * zero for success else a negative errno value.
 */
int __init usb_add_function(struct usb_configuration *config,
		struct usb_function *function)
{
	int	value = -EINVAL;

	DBG(config->cdev, "adding '%s'/%p to config '%s'/%p\n",
			function->name, function,
			config->label, config);

	if (!function->set_alt || !function->disable)
		goto done;

	function->config = config;
	list_add_tail(&function->list, &config->functions);

	/* REVISIT *require* function->bind? */
	if (function->bind) {
		value = function->bind(config, function);
		if (value < 0) {
			list_del(&function->list);
			function->config = NULL;
		}
	} else
		value = 0;

	/* We allow configurations that don't work at both speeds.
	 * If we run into a lowspeed Linux system, treat it the same
	 * as full speed ... it's the function drivers that will need
	 * to avoid bulk and ISO transfers.
	 */
	if (!config->fullspeed && function->descriptors)
		config->fullspeed = true;
	if (!config->highspeed && function->hs_descriptors)
		config->highspeed = true;

done:
	if (value)
		DBG(config->cdev, "adding '%s'/%p --> %d\n",
				function->name, function, value);
	return value;
}

/**
 * usb_function_deactivate - prevent function and gadget enumeration
 * @function: the function that isn't yet ready to respond
 *
 * Blocks response of the gadget driver to host enumeration by
 * preventing the data line pullup from being activated.  This is
 * normally called during @bind() processing to change from the
 * initial "ready to respond" state, or when a required resource
 * becomes available.
 *
 * For example, drivers that serve as a passthrough to a userspace
 * daemon can block enumeration unless that daemon (such as an OBEX,
 * MTP, or print server) is ready to handle host requests.
 *
 * Not all systems support software control of their USB peripheral
 * data pullups.
 *
 * Returns zero on success, else negative errno.
 */
int usb_function_deactivate(struct usb_function *function)
{
	struct usb_composite_dev	*cdev = function->config->cdev;
	unsigned long			flags;
	int				status = 0;

	spin_lock_irqsave(&cdev->lock, flags);

	if (cdev->deactivations == 0)
		status = usb_gadget_disconnect(cdev->gadget);
	if (status == 0)
		cdev-