linux/drivers/usb/gadget/function/f_loopback.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * f_loopback.c - USB peripheral loopback configuration driver
 *
 * Copyright (C) 2003-2008 David Brownell
 * Copyright (C) 2008 by Nokia Corporation
 */

/* #define VERBOSE_DEBUG */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/usb/composite.h>
#include <linux/usb/func_utils.h>

#include "g_zero.h"

/*
 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
 *
 * This takes messages of various sizes written OUT to a device, and loops
 * them back so they can be read IN from it.  It has been used by certain
 * test applications.  It supports limited testing of data queueing logic.
 */
struct f_loopback { … };

static inline struct f_loopback *func_to_loop(struct usb_function *f)
{ … }

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

static struct usb_interface_descriptor loopback_intf = …;

/* full speed support: */

static struct usb_endpoint_descriptor fs_loop_source_desc = …;

static struct usb_endpoint_descriptor fs_loop_sink_desc = …;

static struct usb_descriptor_header *fs_loopback_descs[] = …;

/* high speed support: */

static struct usb_endpoint_descriptor hs_loop_source_desc = …;

static struct usb_endpoint_descriptor hs_loop_sink_desc = …;

static struct usb_descriptor_header *hs_loopback_descs[] = …;

/* super speed support: */

static struct usb_endpoint_descriptor ss_loop_source_desc = …;

static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = …;

static struct usb_endpoint_descriptor ss_loop_sink_desc = …;

static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = …;

static struct usb_descriptor_header *ss_loopback_descs[] = …;

/* function-specific strings: */

static struct usb_string strings_loopback[] = …;

static struct usb_gadget_strings stringtab_loop = …;

static struct usb_gadget_strings *loopback_strings[] = …;

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

static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
{ … }

static void lb_free_func(struct usb_function *f)
{ … }

static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
{ … }

static void disable_loopback(struct f_loopback *loop)
{ … }

static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
{ … }

static int alloc_requests(struct usb_composite_dev *cdev,
			  struct f_loopback *loop)
{ … }

static int enable_endpoint(struct usb_composite_dev *cdev,
			   struct f_loopback *loop, struct usb_ep *ep)
{ … }

static int
enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
{ … }

static int loopback_set_alt(struct usb_function *f,
		unsigned intf, unsigned alt)
{ … }

static void loopback_disable(struct usb_function *f)
{ … }

static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
{ … }

static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
{ … }

static void lb_attr_release(struct config_item *item)
{ … }

static struct configfs_item_operations lb_item_ops = …;

static ssize_t f_lb_opts_qlen_show(struct config_item *item, char *page)
{ … }

static ssize_t f_lb_opts_qlen_store(struct config_item *item,
				    const char *page, size_t len)
{ … }

CONFIGFS_ATTR(…);

static ssize_t f_lb_opts_bulk_buflen_show(struct config_item *item, char *page)
{ … }

static ssize_t f_lb_opts_bulk_buflen_store(struct config_item *item,
				    const char *page, size_t len)
{ … }

CONFIGFS_ATTR(…);

static struct configfs_attribute *lb_attrs[] = …;

static const struct config_item_type lb_func_type = …;

static void lb_free_instance(struct usb_function_instance *fi)
{ … }

static struct usb_function_instance *loopback_alloc_instance(void)
{ … }
DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);

int __init lb_modinit(void)
{ … }

void __exit lb_modexit(void)
{ … }

MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;