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 req->zero = (req->actual < req->length);
257 req->length = req->actual;
260 /* queue the buffer for some later OUT packet */
261 req->length = buflen;
262 status = usb_ep_queue(ep, req, GFP_ATOMIC);
266 /* "should never get here" */
270 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
271 status, req->actual, req->length);
274 /* NOTE: since this driver doesn't maintain an explicit record
275 * of requests it submitted (just maintains qlen count), we
276 * rely on the hardware driver to clean up on disconnect or
279 case -ECONNABORTED: /* hardware forced ep reset */
280 case -ECONNRESET: /* request dequeued */
281 case -ESHUTDOWN: /* disconnect from host */
282 free_ep_req(ep, req);
287 static void disable_loopback(struct f_loopback *loop)
289 struct usb_composite_dev *cdev;
291 cdev = loop->function.config->cdev;
292 disable_endpoints(cdev, loop->in_ep, loop->out_ep, NULL, NULL, NULL,
294 VDBG(cdev, "%s disabled\n", loop->function.name);
297 static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
299 return alloc_ep_req(ep, len, buflen);
302 static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop,
305 struct usb_request *req;
310 * one endpoint writes data back IN to the host while another endpoint
311 * just reads OUT packets
313 result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
316 result = usb_ep_enable(ep);
319 ep->driver_data = loop;
322 * allocate a bunch of read buffers and queue them all at once.
323 * we buffer at most 'qlen' transfers; fewer if any need more
324 * than 'buflen' bytes each.
326 for (i = 0; i < qlen && result == 0; i++) {
327 req = lb_alloc_ep_req(ep, 0);
331 req->complete = loopback_complete;
332 result = usb_ep_queue(ep, req, GFP_ATOMIC);
334 ERROR(cdev, "%s queue req --> %d\n",
350 enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
354 result = enable_endpoint(cdev, loop, loop->in_ep);
358 result = enable_endpoint(cdev, loop, loop->out_ep);
362 DBG(cdev, "%s enabled\n", loop->function.name);
366 static int loopback_set_alt(struct usb_function *f,
367 unsigned intf, unsigned alt)
369 struct f_loopback *loop = func_to_loop(f);
370 struct usb_composite_dev *cdev = f->config->cdev;
372 /* we know alt is zero */
373 if (loop->in_ep->driver_data)
374 disable_loopback(loop);
375 return enable_loopback(cdev, loop);
378 static void loopback_disable(struct usb_function *f)
380 struct f_loopback *loop = func_to_loop(f);
382 disable_loopback(loop);
385 static struct usb_function *loopback_alloc(struct usb_function_instance *fi)
387 struct f_loopback *loop;
388 struct f_lb_opts *lb_opts;
390 loop = kzalloc(sizeof *loop, GFP_KERNEL);
392 return ERR_PTR(-ENOMEM);
394 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
396 mutex_lock(&lb_opts->lock);
398 mutex_unlock(&lb_opts->lock);
400 buflen = lb_opts->bulk_buflen;
401 qlen = lb_opts->qlen;
405 loop->function.name = "loopback";
406 loop->function.bind = loopback_bind;
407 loop->function.set_alt = loopback_set_alt;
408 loop->function.disable = loopback_disable;
409 loop->function.strings = loopback_strings;
411 loop->function.free_func = lb_free_func;
413 return &loop->function;
416 static inline struct f_lb_opts *to_f_lb_opts(struct config_item *item)
418 return container_of(to_config_group(item), struct f_lb_opts,
422 CONFIGFS_ATTR_STRUCT(f_lb_opts);
423 CONFIGFS_ATTR_OPS(f_lb_opts);
425 static void lb_attr_release(struct config_item *item)
427 struct f_lb_opts *lb_opts = to_f_lb_opts(item);
429 usb_put_function_instance(&lb_opts->func_inst);
432 static struct configfs_item_operations lb_item_ops = {
433 .release = lb_attr_release,
434 .show_attribute = f_lb_opts_attr_show,
435 .store_attribute = f_lb_opts_attr_store,
438 static ssize_t f_lb_opts_qlen_show(struct f_lb_opts *opts, char *page)
442 mutex_lock(&opts->lock);
443 result = sprintf(page, "%d", opts->qlen);
444 mutex_unlock(&opts->lock);
449 static ssize_t f_lb_opts_qlen_store(struct f_lb_opts *opts,
450 const char *page, size_t len)
455 mutex_lock(&opts->lock);
461 ret = kstrtou32(page, 0, &num);
468 mutex_unlock(&opts->lock);
472 static struct f_lb_opts_attribute f_lb_opts_qlen =
473 __CONFIGFS_ATTR(qlen, S_IRUGO | S_IWUSR,
475 f_lb_opts_qlen_store);
477 static ssize_t f_lb_opts_bulk_buflen_show(struct f_lb_opts *opts, char *page)
481 mutex_lock(&opts->lock);
482 result = sprintf(page, "%d", opts->bulk_buflen);
483 mutex_unlock(&opts->lock);
488 static ssize_t f_lb_opts_bulk_buflen_store(struct f_lb_opts *opts,
489 const char *page, size_t len)
494 mutex_lock(&opts->lock);
500 ret = kstrtou32(page, 0, &num);
504 opts->bulk_buflen = num;
507 mutex_unlock(&opts->lock);
511 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen =
512 __CONFIGFS_ATTR(buflen, S_IRUGO | S_IWUSR,
513 f_lb_opts_bulk_buflen_show,
514 f_lb_opts_bulk_buflen_store);
516 static struct configfs_attribute *lb_attrs[] = {
517 &f_lb_opts_qlen.attr,
518 &f_lb_opts_bulk_buflen.attr,
522 static struct config_item_type lb_func_type = {
523 .ct_item_ops = &lb_item_ops,
524 .ct_attrs = lb_attrs,
525 .ct_owner = THIS_MODULE,
528 static void lb_free_instance(struct usb_function_instance *fi)
530 struct f_lb_opts *lb_opts;
532 lb_opts = container_of(fi, struct f_lb_opts, func_inst);
536 static struct usb_function_instance *loopback_alloc_instance(void)
538 struct f_lb_opts *lb_opts;
540 lb_opts = kzalloc(sizeof(*lb_opts), GFP_KERNEL);
542 return ERR_PTR(-ENOMEM);
543 mutex_init(&lb_opts->lock);
544 lb_opts->func_inst.free_func_inst = lb_free_instance;
545 lb_opts->bulk_buflen = GZERO_BULK_BUFLEN;
546 lb_opts->qlen = GZERO_QLEN;
548 config_group_init_type_name(&lb_opts->func_inst.group, "",
551 return &lb_opts->func_inst;
553 DECLARE_USB_FUNCTION(Loopback, loopback_alloc_instance, loopback_alloc);
555 int __init lb_modinit(void)
559 ret = usb_function_register(&Loopbackusb_func);
564 void __exit lb_modexit(void)
566 usb_function_unregister(&Loopbackusb_func);
569 MODULE_LICENSE("GPL");