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
);
293 VDBG(cdev
, "%s disabled\n", loop
->function
.name
);
296 static inline struct usb_request
*lb_alloc_ep_req(struct usb_ep
*ep
, int len
)
298 return alloc_ep_req(ep
, len
, buflen
);
301 static int enable_endpoint(struct usb_composite_dev
*cdev
, struct f_loopback
*loop
,
304 struct usb_request
*req
;
309 * one endpoint writes data back IN to the host while another endpoint
310 * just reads OUT packets
312 result
= config_ep_by_speed(cdev
->gadget
, &(loop
->function
), ep
);
315 result
= usb_ep_enable(ep
);
318 ep
->driver_data
= loop
;
321 * allocate a bunch of read buffers and queue them all at once.
322 * we buffer at most 'qlen' transfers; fewer if any need more
323 * than 'buflen' bytes each.
325 for (i
= 0; i
< qlen
&& result
== 0; i
++) {
326 req
= lb_alloc_ep_req(ep
, 0);
330 req
->complete
= loopback_complete
;
331 result
= usb_ep_queue(ep
, req
, GFP_ATOMIC
);
333 ERROR(cdev
, "%s queue req --> %d\n",
349 enable_loopback(struct usb_composite_dev
*cdev
, struct f_loopback
*loop
)
353 result
= enable_endpoint(cdev
, loop
, loop
->in_ep
);
357 result
= enable_endpoint(cdev
, loop
, loop
->out_ep
);
361 DBG(cdev
, "%s enabled\n", loop
->function
.name
);
365 static int loopback_set_alt(struct usb_function
*f
,
366 unsigned intf
, unsigned alt
)
368 struct f_loopback
*loop
= func_to_loop(f
);
369 struct usb_composite_dev
*cdev
= f
->config
->cdev
;
371 /* we know alt is zero */
372 if (loop
->in_ep
->driver_data
)
373 disable_loopback(loop
);
374 return enable_loopback(cdev
, loop
);
377 static void loopback_disable(struct usb_function
*f
)
379 struct f_loopback
*loop
= func_to_loop(f
);
381 disable_loopback(loop
);
384 static struct usb_function
*loopback_alloc(struct usb_function_instance
*fi
)
386 struct f_loopback
*loop
;
387 struct f_lb_opts
*lb_opts
;
389 loop
= kzalloc(sizeof *loop
, GFP_KERNEL
);
391 return ERR_PTR(-ENOMEM
);
393 lb_opts
= container_of(fi
, struct f_lb_opts
, func_inst
);
395 mutex_lock(&lb_opts
->lock
);
397 mutex_unlock(&lb_opts
->lock
);
399 buflen
= lb_opts
->bulk_buflen
;
400 qlen
= lb_opts
->qlen
;
404 loop
->function
.name
= "loopback";
405 loop
->function
.bind
= loopback_bind
;
406 loop
->function
.set_alt
= loopback_set_alt
;
407 loop
->function
.disable
= loopback_disable
;
408 loop
->function
.strings
= loopback_strings
;
410 loop
->function
.free_func
= lb_free_func
;
412 return &loop
->function
;
415 static inline struct f_lb_opts
*to_f_lb_opts(struct config_item
*item
)
417 return container_of(to_config_group(item
), struct f_lb_opts
,
421 CONFIGFS_ATTR_STRUCT(f_lb_opts
);
422 CONFIGFS_ATTR_OPS(f_lb_opts
);
424 static void lb_attr_release(struct config_item
*item
)
426 struct f_lb_opts
*lb_opts
= to_f_lb_opts(item
);
428 usb_put_function_instance(&lb_opts
->func_inst
);
431 static struct configfs_item_operations lb_item_ops
= {
432 .release
= lb_attr_release
,
433 .show_attribute
= f_lb_opts_attr_show
,
434 .store_attribute
= f_lb_opts_attr_store
,
437 static ssize_t
f_lb_opts_qlen_show(struct f_lb_opts
*opts
, char *page
)
441 mutex_lock(&opts
->lock
);
442 result
= sprintf(page
, "%d", opts
->qlen
);
443 mutex_unlock(&opts
->lock
);
448 static ssize_t
f_lb_opts_qlen_store(struct f_lb_opts
*opts
,
449 const char *page
, size_t len
)
454 mutex_lock(&opts
->lock
);
460 ret
= kstrtou32(page
, 0, &num
);
467 mutex_unlock(&opts
->lock
);
471 static struct f_lb_opts_attribute f_lb_opts_qlen
=
472 __CONFIGFS_ATTR(qlen
, S_IRUGO
| S_IWUSR
,
474 f_lb_opts_qlen_store
);
476 static ssize_t
f_lb_opts_bulk_buflen_show(struct f_lb_opts
*opts
, char *page
)
480 mutex_lock(&opts
->lock
);
481 result
= sprintf(page
, "%d", opts
->bulk_buflen
);
482 mutex_unlock(&opts
->lock
);
487 static ssize_t
f_lb_opts_bulk_buflen_store(struct f_lb_opts
*opts
,
488 const char *page
, size_t len
)
493 mutex_lock(&opts
->lock
);
499 ret
= kstrtou32(page
, 0, &num
);
503 opts
->bulk_buflen
= num
;
506 mutex_unlock(&opts
->lock
);
510 static struct f_lb_opts_attribute f_lb_opts_bulk_buflen
=
511 __CONFIGFS_ATTR(buflen
, S_IRUGO
| S_IWUSR
,
512 f_lb_opts_bulk_buflen_show
,
513 f_lb_opts_bulk_buflen_store
);
515 static struct configfs_attribute
*lb_attrs
[] = {
516 &f_lb_opts_qlen
.attr
,
517 &f_lb_opts_bulk_buflen
.attr
,
521 static struct config_item_type lb_func_type
= {
522 .ct_item_ops
= &lb_item_ops
,
523 .ct_attrs
= lb_attrs
,
524 .ct_owner
= THIS_MODULE
,
527 static void lb_free_instance(struct usb_function_instance
*fi
)
529 struct f_lb_opts
*lb_opts
;
531 lb_opts
= container_of(fi
, struct f_lb_opts
, func_inst
);
535 static struct usb_function_instance
*loopback_alloc_instance(void)
537 struct f_lb_opts
*lb_opts
;
539 lb_opts
= kzalloc(sizeof(*lb_opts
), GFP_KERNEL
);
541 return ERR_PTR(-ENOMEM
);
542 mutex_init(&lb_opts
->lock
);
543 lb_opts
->func_inst
.free_func_inst
= lb_free_instance
;
544 lb_opts
->bulk_buflen
= GZERO_BULK_BUFLEN
;
545 lb_opts
->qlen
= GZERO_QLEN
;
547 config_group_init_type_name(&lb_opts
->func_inst
.group
, "",
550 return &lb_opts
->func_inst
;
552 DECLARE_USB_FUNCTION(Loopback
, loopback_alloc_instance
, loopback_alloc
);
554 int __init
lb_modinit(void)
558 ret
= usb_function_register(&Loopbackusb_func
);
563 void __exit
lb_modexit(void)
565 usb_function_unregister(&Loopbackusb_func
);
568 MODULE_LICENSE("GPL");