2 * f_loopback.c - USB peripheral loopback configuration driver
4 * Copyright (C) 2003-2008 David Brownell
5 * Copyright (C) 2008 by Nokia Corporation
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
13 /* #define VERBOSE_DEBUG */
15 #include <linux/slab.h>
16 #include <linux/kernel.h>
17 #include <linux/device.h>
18 #include <linux/module.h>
19 #include <linux/err.h>
20 #include <linux/usb/composite.h>
26 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals,
28 * This takes messages of various sizes written OUT to a device, and loops
29 * them back so they can be read IN from it. It has been used by certain
30 * test applications. It supports limited testing of data queueing logic.
33 * This is currently packaged as a configuration driver, which can't be
34 * combined with other functions to make composite devices. However, it
35 * can be combined with other independent configurations.
38 struct usb_function function;
41 struct usb_ep *out_ep;
44 static inline struct f_loopback *func_to_loop(struct usb_function *f)
46 return container_of(f, struct f_loopback, function);
50 static unsigned buflen;
52 /*-------------------------------------------------------------------------*/
54 static struct usb_interface_descriptor loopback_intf = {
55 .bLength = sizeof loopback_intf,
56 .bDescriptorType = USB_DT_INTERFACE,
59 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
60 /* .iInterface = DYNAMIC */
63 /* full speed support: */
65 static struct usb_endpoint_descriptor fs_loop_source_desc = {
66 .bLength = USB_DT_ENDPOINT_SIZE,
67 .bDescriptorType = USB_DT_ENDPOINT,
69 .bEndpointAddress = USB_DIR_IN,
70 .bmAttributes = USB_ENDPOINT_XFER_BULK,
73 static struct usb_endpoint_descriptor fs_loop_sink_desc = {
74 .bLength = USB_DT_ENDPOINT_SIZE,
75 .bDescriptorType = USB_DT_ENDPOINT,
77 .bEndpointAddress = USB_DIR_OUT,
78 .bmAttributes = USB_ENDPOINT_XFER_BULK,
81 static struct usb_descriptor_header *fs_loopback_descs[] = {
82 (struct usb_descriptor_header *) &loopback_intf,
83 (struct usb_descriptor_header *) &fs_loop_sink_desc,
84 (struct usb_descriptor_header *) &fs_loop_source_desc,
88 /* high speed support: */
90 static struct usb_endpoint_descriptor hs_loop_source_desc = {
91 .bLength = USB_DT_ENDPOINT_SIZE,
92 .bDescriptorType = USB_DT_ENDPOINT,
94 .bmAttributes = USB_ENDPOINT_XFER_BULK,
95 .wMaxPacketSize = cpu_to_le16(512),
98 static struct usb_endpoint_descriptor hs_loop_sink_desc = {
99 .bLength = USB_DT_ENDPOINT_SIZE,
100 .bDescriptorType = USB_DT_ENDPOINT,
102 .bmAttributes = USB_ENDPOINT_XFER_BULK,
103 .wMaxPacketSize = cpu_to_le16(512),
106 static struct usb_descriptor_header *hs_loopback_descs[] = {
107 (struct usb_descriptor_header *) &loopback_intf,
108 (struct usb_descriptor_header *) &hs_loop_source_desc,
109 (struct usb_descriptor_header *) &hs_loop_sink_desc,
113 /* super speed support: */
115 static struct usb_endpoint_descriptor ss_loop_source_desc = {
116 .bLength = USB_DT_ENDPOINT_SIZE,
117 .bDescriptorType = USB_DT_ENDPOINT,
119 .bmAttributes = USB_ENDPOINT_XFER_BULK,
120 .wMaxPacketSize = cpu_to_le16(1024),
123 static struct usb_ss_ep_comp_descriptor ss_loop_source_comp_desc = {
124 .bLength = USB_DT_SS_EP_COMP_SIZE,
125 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
128 .wBytesPerInterval = 0,
131 static struct usb_endpoint_descriptor ss_loop_sink_desc = {
132 .bLength = USB_DT_ENDPOINT_SIZE,
133 .bDescriptorType = USB_DT_ENDPOINT,
135 .bmAttributes = USB_ENDPOINT_XFER_BULK,
136 .wMaxPacketSize = cpu_to_le16(1024),
139 static struct usb_ss_ep_comp_descriptor ss_loop_sink_comp_desc = {
140 .bLength = USB_DT_SS_EP_COMP_SIZE,
141 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
144 .wBytesPerInterval = 0,
147 static struct usb_descriptor_header *ss_loopback_descs[] = {
148 (struct usb_descriptor_header *) &loopback_intf,
149 (struct usb_descriptor_header *) &ss_loop_source_desc,
150 (struct usb_descriptor_header *) &ss_loop_source_comp_desc,
151 (struct usb_descriptor_header *) &ss_loop_sink_desc,
152 (struct usb_descriptor_header *) &ss_loop_sink_comp_desc,
156 /* function-specific strings: */
158 static struct usb_string strings_loopback[] = {
159 [0].s = "loop input to output",
160 { } /* end of list */
163 static struct usb_gadget_strings stringtab_loop = {
164 .language = 0x0409, /* en-us */
165 .strings = strings_loopback,
168 static struct usb_gadget_strings *loopback_strings[] = {
173 /*-------------------------------------------------------------------------*/
175 static int loopback_bind(struct usb_configuration *c, struct usb_function *f)
177 struct usb_composite_dev *cdev = c->cdev;
178 struct f_loopback *loop = func_to_loop(f);
182 /* allocate interface ID(s) */
183 id = usb_interface_id(c, f);
186 loopback_intf.bInterfaceNumber = id;
188 id = usb_string_id(cdev);
191 strings_loopback[0].id = id;
192 loopback_intf.iInterface = id;
194 /* allocate endpoints */
196 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc);
199 ERROR(cdev, "%s: can't autoconfigure on %s\n",
200 f->name, cdev->gadget->name);
203 loop->in_ep->driver_data = cdev; /* claim */
205 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc);
208 loop->out_ep->driver_data = cdev; /* claim */
210 /* support high speed hardware */
211 hs_loop_source_desc.bEndpointAddress =
212 fs_loop_source_desc.bEndpointAddress;
213 hs_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
215 /* support super speed hardware */
216 ss_loop_source_desc.bEndpointAddress =
217 fs_loop_source_desc.bEndpointAddress;
218 ss_loop_sink_desc.bEndpointAddress = fs_loop_sink_desc.bEndpointAddress;
220 ret = usb_assign_descriptors(f, fs_loopback_descs, hs_loopback_descs,
225 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n",
226 (gadget_is_superspeed(c->cdev->gadget) ? "super" :
227 (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
228 f->name, loop->in_ep->name, loop->out_ep->name);
232 static void lb_free_func(struct usb_function *f)
234 struct f_lb_opts *opts;
236 opts = container_of(f->fi, struct f_lb_opts, func_inst);
238 mutex_lock(&opts->lock);
240 mutex_unlock(&opts->lock);
242 usb_free_all_descriptors(f);
243 kfree(func_to_loop(f));
246 static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
248 struct f_loopback *loop = ep->driver_data;
249 struct usb_composite_dev *cdev = loop->function.config->cdev;
250 int status = req->status;
254 case 0: /* normal completion? */
255 if (ep == loop->out_ep) {
256 /* loop this OUT packet back IN to the host */
257 req->zero = (req->actual < req->length);
258 req->length = req->actual;
259 status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC);
263 /* "should never get here" */
264 ERROR(cdev, "can't loop %s to %s: %d\n",
265 ep->name, loop->in_ep->name,
269 /* queue the buffer for some later OUT packet */
270 req->length = buflen;
271 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC);
275 /* "should never get here" */
279 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
280 status, req->actual, req->length);
283 /* NOTE: since this driver doesn't maintain an explicit record
284 * of requests it submitted (just maintains qlen count), we
285 * rely on the hardware driver to clean up on disconnect or
288 case -ECONNABORTED: /* hardware forced ep reset */
289 case -ECONNRESET: /* request dequeued */
290 case -ESHUTDOWN: /* disconnect from host */
291 free_ep_req(ep, req);
296 static void disable_loopback(struct f_loopback *loop)
298 struct usb_composite_dev *cdev;
300 cdev = loop->function.config->cdev;
301 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL);
302 VDBG(cdev, "%s disabled\n", loop->function.name);
305 static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
307 return alloc_ep_req(ep, len, buflen);
311 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
315 struct usb_request *req;
318 /* one endpoint writes data back IN to the host */
320 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
323 result = usb_ep_enable(ep);
326 ep->driver_data = loop;
328 /* one endpoint just reads OUT packets */
330 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
334 result = usb_ep_enable(ep);
339 ep->driver_data = NULL;
342 ep->driver_data = loop;
344 /* allocate a bunch of read buffers and queue them all at once.
345 * we buffer at most 'qlen' transfers; fewer if any need more
346 * than 'buflen' bytes each.
348 for (i = 0; i < qlen && result == 0; i++) {
349 req = lb_alloc_ep_req(ep, 0);
351 req->complete = loopback_complete;
352 result = usb_ep_queue(ep, req, GFP_ATOMIC);
354 ERROR(cdev, "%s queue req --> %d\n",
358 ep->driver_data = NULL;
364 DBG(cdev, "%s enabled\n", loop->function.name);
368 static int loopback_set_alt(struct usb_function *f,
369 unsigned intf, unsigned alt)
371 struct f_loopback *loop = func_to_loop(f);
372 struct usb_composite_dev *cdev = f->config->cdev;
374 /* we know alt is zero */
375 if (loop->in_ep->driver_data)
376 disable_loopback(loop);
377 return enable_loopback(cdev, loop);
380 static void loopback_disable(struct usb_function *f)
382 struct f_loopback *loop = func_to_loop(f);
384 disable_loopback(loop);
387 static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
389 struct f_loopback *loop;
390 struct f_lb_opts *lb_opts;
392 loop = kzalloc(sizeof *loop, GFP_KERNEL);
394 return ERR_PTR(-ENOMEM);
396 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
398 mutex_lock(&lb_opts->lock);
400 mutex_unlock(&lb_opts->lock);
402 buflen = lb_opts->bulk_buflen;
403 qlen = lb_opts->qlen;
407 loop->function.name = "loopback";
408 loop->function.bind = loopback_bind;
409 loop->function.set_alt = loopback_set_alt;
410 loop->function.disable = loopback_disable;
411 loop->function.strings = loopback_strings;
413 loop->function.free_func = lb_free_func;
415 return &loop->function;
418 static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
420 return container_of(to_config_group(item), struct f_lb_opts,
424 CONFIGFS_ATTR_STRUCT(f_lb_opts);
425 CONFIGFS_ATTR_OPS(f_lb_opts);
427 static void lb_attr_release(struct config_item *item)
429 struct f_lb_opts *lb_opts = to_f_lb_opts(item);
431 usb_put_function_instance(&lb_opts->func_inst);
434 static struct configfs_item_operations lb_item_ops = {
435 .release = lb_attr_release,
436 .show_attribute = f_lb_opts_attr_show,
437 .store_attribute = f_lb_opts_attr_store,
440 static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page)
444 mutex_lock(&opts->lock);
445 result = sprintf(page, "%d", opts->qlen);
446 mutex_unlock(&opts->lock);
451 static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts,
452 const char *page, size_t len)
457 mutex_lock(&opts->lock);
463 ret = kstrtou32(page, 0, &num);
470 mutex_unlock(&opts->lock);
474 static struct f_lb_opts_attribute f_lb_opts_qlen =
475 __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR,
477 f_lb_opts_qlen_store);
479 static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page)
483 mutex_lock(&opts->lock);
484 result = sprintf(page, "%d", opts->bulk_buflen);
485 mutex_unlock(&opts->lock);
490 static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts,
491 const char *page, size_t len)
496 mutex_lock(&opts->lock);
502 ret = kstrtou32(page, 0, &num);
506 opts->bulk_buflen = num;
509 mutex_unlock(&opts->lock);
513 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen =
514 __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR,
515 f_lb_opts_bulk_buflen_show,
516 f_lb_opts_bulk_buflen_store);
518 static struct configfs_attribute *lb_attrs[] = {
519 &f_lb_opts_qlen.attr,
520 &f_lb_opts_bulk_buflen.attr,
524 static struct config_item_type lb_func_type = {
525 .ct_item_ops = &lb_item_ops,
526 .ct_attrs = lb_attrs,
527 .ct_owner = THIS_MODULE,
530 static void lb_free_instance(struct usb_function_instance *fi)
532 struct f_lb_opts *lb_opts;
534 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
538 static struct usb_function_instance *loopback_alloc_instance(void)
540 struct f_lb_opts *lb_opts;
542 lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
544 return ERR_PTR(-ENOMEM);
545 mutex_init(&lb_opts->lock);
546 lb_opts->func_inst.free_func_inst = lb_free_instance;
547 lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
548 lb_opts->qlen = GZERO_QLEN;
550 config_group_init_type_name(&lb_opts->func_inst.group, "",
553 return &lb_opts->func_inst;
555 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
557 int __init lb_modinit(void)
561 ret = usb_function_register(&Loopbackusb_func);
566 void __exit lb_modexit(void)
568 usb_function_unregister(&Loopbackusb_func);
571 MODULE_LICENSE("GPL");