1/* 2 * f_loopback.c - USB peripheral loopback configuration driver 3 * 4 * Copyright (C) 2003-2008 David Brownell 5 * Copyright (C) 2008 by Nokia Corporation 6 * 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. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22/* #define VERBOSE_DEBUG */ 23 24#include <linux/slab.h> 25#include <linux/kernel.h> 26#include <linux/device.h> 27 28#include "g_zero.h" 29#include "gadget_chips.h" 30 31 32/* 33 * LOOPBACK FUNCTION ... a testing vehicle for USB peripherals, 34 * 35 * This takes messages of various sizes written OUT to a device, and loops 36 * them back so they can be read IN from it. It has been used by certain 37 * test applications. It supports limited testing of data queueing logic. 38 * 39 * 40 * This is currently packaged as a configuration driver, which can't be 41 * combined with other functions to make composite devices. However, it 42 * can be combined with other independent configurations. 43 */ 44struct f_loopback { 45 struct usb_function function; 46 47 struct usb_ep *in_ep; 48 struct usb_ep *out_ep; 49}; 50 51static inline struct f_loopback *func_to_loop(struct usb_function *f) 52{ 53 return container_of(f, struct f_loopback, function); 54} 55 56static unsigned qlen = 32; 57module_param(qlen, uint, 0); 58MODULE_PARM_DESC(qlenn, "depth of loopback queue"); 59 60/*-------------------------------------------------------------------------*/ 61 62static struct usb_interface_descriptor loopback_intf = { 63 .bLength = sizeof loopback_intf, 64 .bDescriptorType = USB_DT_INTERFACE, 65 66 .bNumEndpoints = 2, 67 .bInterfaceClass = USB_CLASS_VENDOR_SPEC, 68 /* .iInterface = DYNAMIC */ 69}; 70 71/* full speed support: */ 72 73static struct usb_endpoint_descriptor fs_loop_source_desc = { 74 .bLength = USB_DT_ENDPOINT_SIZE, 75 .bDescriptorType = USB_DT_ENDPOINT, 76 77 .bEndpointAddress = USB_DIR_IN, 78 .bmAttributes = USB_ENDPOINT_XFER_BULK, 79}; 80 81static struct usb_endpoint_descriptor fs_loop_sink_desc = { 82 .bLength = USB_DT_ENDPOINT_SIZE, 83 .bDescriptorType = USB_DT_ENDPOINT, 84 85 .bEndpointAddress = USB_DIR_OUT, 86 .bmAttributes = USB_ENDPOINT_XFER_BULK, 87}; 88 89static struct usb_descriptor_header *fs_loopback_descs[] = { 90 (struct usb_descriptor_header *) &loopback_intf, 91 (struct usb_descriptor_header *) &fs_loop_sink_desc, 92 (struct usb_descriptor_header *) &fs_loop_source_desc, 93 NULL, 94}; 95 96/* high speed support: */ 97 98static struct usb_endpoint_descriptor hs_loop_source_desc = { 99 .bLength = USB_DT_ENDPOINT_SIZE, 100 .bDescriptorType = USB_DT_ENDPOINT, 101 102 .bmAttributes = USB_ENDPOINT_XFER_BULK, 103 .wMaxPacketSize = cpu_to_le16(512), 104}; 105 106static struct usb_endpoint_descriptor hs_loop_sink_desc = { 107 .bLength = USB_DT_ENDPOINT_SIZE, 108 .bDescriptorType = USB_DT_ENDPOINT, 109 110 .bmAttributes = USB_ENDPOINT_XFER_BULK, 111 .wMaxPacketSize = cpu_to_le16(512), 112}; 113 114static struct usb_descriptor_header *hs_loopback_descs[] = { 115 (struct usb_descriptor_header *) &loopback_intf, 116 (struct usb_descriptor_header *) &hs_loop_source_desc, 117 (struct usb_descriptor_header *) &hs_loop_sink_desc, 118 NULL, 119}; 120 121/* function-specific strings: */ 122 123static struct usb_string strings_loopback[] = { 124 [0].s = "loop input to output", 125 { } /* end of list */ 126}; 127 128static struct usb_gadget_strings stringtab_loop = { 129 .language = 0x0409, /* en-us */ 130 .strings = strings_loopback, 131}; 132 133static struct usb_gadget_strings *loopback_strings[] = { 134 &stringtab_loop, 135 NULL, 136}; 137 138/*-------------------------------------------------------------------------*/ 139 140static int __init 141loopback_bind(struct usb_configuration *c, struct usb_function *f) 142{ 143 struct usb_composite_dev *cdev = c->cdev; 144 struct f_loopback *loop = func_to_loop(f); 145 int id; 146 147 /* allocate interface ID(s) */ 148 id = usb_interface_id(c, f); 149 if (id < 0) 150 return id; 151 loopback_intf.bInterfaceNumber = id; 152 153 /* allocate endpoints */ 154 155 loop->in_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_source_desc); 156 if (!loop->in_ep) { 157autoconf_fail: 158 ERROR(cdev, "%s: can't autoconfigure on %s\n", 159 f->name, cdev->gadget->name); 160 return -ENODEV; 161 } 162 loop->in_ep->driver_data = cdev; /* claim */ 163 164 loop->out_ep = usb_ep_autoconfig(cdev->gadget, &fs_loop_sink_desc); 165 if (!loop->out_ep) 166 goto autoconf_fail; 167 loop->out_ep->driver_data = cdev; /* claim */ 168 169 /* support high speed hardware */ 170 if (gadget_is_dualspeed(c->cdev->gadget)) { 171 hs_loop_source_desc.bEndpointAddress = 172 fs_loop_source_desc.bEndpointAddress; 173 hs_loop_sink_desc.bEndpointAddress = 174 fs_loop_sink_desc.bEndpointAddress; 175 f->hs_descriptors = hs_loopback_descs; 176 } 177 178 DBG(cdev, "%s speed %s: IN/%s, OUT/%s\n", 179 gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full", 180 f->name, loop->in_ep->name, loop->out_ep->name); 181 return 0; 182} 183 184static void 185loopback_unbind(struct usb_configuration *c, struct usb_function *f) 186{ 187 kfree(func_to_loop(f)); 188} 189 190static void loopback_complete(struct usb_ep *ep, struct usb_request *req) 191{ 192 struct f_loopback *loop = ep->driver_data; 193 struct usb_composite_dev *cdev = loop->function.config->cdev; 194 int status = req->status; 195 196 switch (status) { 197 198 case 0: /* normal completion? */ 199 if (ep == loop->out_ep) { 200 /* loop this OUT packet back IN to the host */ 201 req->zero = (req->actual < req->length); 202 req->length = req->actual; 203 status = usb_ep_queue(loop->in_ep, req, GFP_ATOMIC); 204 if (status == 0) 205 return; 206 207 /* "should never get here" */ 208 ERROR(cdev, "can't loop %s to %s: %d\n", 209 ep->name, loop->in_ep->name, 210 status); 211 } 212 213 /* queue the buffer for some later OUT packet */ 214 req->length = buflen; 215 status = usb_ep_queue(loop->out_ep, req, GFP_ATOMIC); 216 if (status == 0) 217 return; 218 219 /* "should never get here" */ 220 /* FALLTHROUGH */ 221 222 default: 223 ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name, 224 status, req->actual, req->length); 225 /* FALLTHROUGH */ 226 227 /* NOTE: since this driver doesn't maintain an explicit record 228 * of requests it submitted (just maintains qlen count), we 229 * rely on the hardware driver to clean up on disconnect or 230 * endpoint disable. 231 */ 232 case -ECONNABORTED: /* hardware forced ep reset */ 233 case -ECONNRESET: /* request dequeued */ 234 case -ESHUTDOWN: /* disconnect from host */ 235 free_ep_req(ep, req); 236 return; 237 } 238} 239 240static void disable_loopback(struct f_loopback *loop) 241{ 242 struct usb_composite_dev *cdev; 243 244 cdev = loop->function.config->cdev; 245 disable_endpoints(cdev, loop->in_ep, loop->out_ep); 246 VDBG(cdev, "%s disabled\n", loop->function.name); 247} 248 249static int 250enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop) 251{ 252 int result = 0; 253 const struct usb_endpoint_descriptor *src, *sink; 254 struct usb_ep *ep; 255 struct usb_request *req; 256 unsigned i; 257 258 src = ep_choose(cdev->gadget, 259 &hs_loop_source_desc, &fs_loop_source_desc); 260 sink = ep_choose(cdev->gadget, 261 &hs_loop_sink_desc, &fs_loop_sink_desc); 262 263 /* one endpoint writes data back IN to the host */ 264 ep = loop->in_ep; 265 result = usb_ep_enable(ep, src); 266 if (result < 0) 267 return result; 268 ep->driver_data = loop; 269 270 /* one endpoint just reads OUT packets */ 271 ep = loop->out_ep; 272 result = usb_ep_enable(ep, sink); 273 if (result < 0) { 274fail0: 275 ep = loop->in_ep; 276 usb_ep_disable(ep); 277 ep->driver_data = NULL; 278 return result; 279 } 280 ep->driver_data = loop; 281 282 /* allocate a bunch of read buffers and queue them all at once. 283 * we buffer at most 'qlen' transfers; fewer if any need more 284 * than 'buflen' bytes each. 285 */ 286 for (i = 0; i < qlen && result == 0; i++) { 287 req = alloc_ep_req(ep); 288 if (req) { 289 req->complete = loopback_complete; 290 result = usb_ep_queue(ep, req, GFP_ATOMIC); 291 if (result) 292 ERROR(cdev, "%s queue req --> %d\n", 293 ep->name, result); 294 } else { 295 usb_ep_disable(ep); 296 ep->driver_data = NULL; 297 result = -ENOMEM; 298 goto fail0; 299 } 300 } 301 302 DBG(cdev, "%s enabled\n", loop->function.name); 303 return result; 304} 305 306static int loopback_set_alt(struct usb_function *f, 307 unsigned intf, unsigned alt) 308{ 309 struct f_loopback *loop = func_to_loop(f); 310 struct usb_composite_dev *cdev = f->config->cdev; 311 312 /* we know alt is zero */ 313 if (loop->in_ep->driver_data) 314 disable_loopback(loop); 315 return enable_loopback(cdev, loop); 316} 317 318static void loopback_disable(struct usb_function *f) 319{ 320 struct f_loopback *loop = func_to_loop(f); 321 322 disable_loopback(loop); 323} 324 325/*-------------------------------------------------------------------------*/ 326 327static int __ref loopback_bind_config(struct usb_configuration *c) 328{ 329 struct f_loopback *loop; 330 int status; 331 332 loop = kzalloc(sizeof *loop, GFP_KERNEL); 333 if (!loop) 334 return -ENOMEM; 335 336 loop->function.name = "loopback"; 337 loop->function.descriptors = fs_loopback_descs; 338 loop->function.bind = loopback_bind; 339 loop->function.unbind = loopback_unbind; 340 loop->function.set_alt = loopback_set_alt; 341 loop->function.disable = loopback_disable; 342 343 status = usb_add_function(c, &loop->function); 344 if (status) 345 kfree(loop); 346 return status; 347} 348 349static struct usb_configuration loopback_driver = { 350 .label = "loopback", 351 .strings = loopback_strings, 352 .bind = loopback_bind_config, 353 .bConfigurationValue = 2, 354 .bmAttributes = USB_CONFIG_ATT_SELFPOWER, 355 /* .iConfiguration = DYNAMIC */ 356}; 357 358/** 359 * loopback_add - add a loopback testing configuration to a device 360 * @cdev: the device to support the loopback configuration 361 */ 362int __init loopback_add(struct usb_composite_dev *cdev, bool autoresume) 363{ 364 int id; 365 366 /* allocate string ID(s) */ 367 id = usb_string_id(cdev); 368 if (id < 0) 369 return id; 370 strings_loopback[0].id = id; 371 372 loopback_intf.iInterface = id; 373 loopback_driver.iConfiguration = id; 374 375 /* support autoresume for remote wakeup testing */ 376 if (autoresume) 377 sourcesink_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP; 378 379 /* support OTG systems */ 380 if (gadget_is_otg(cdev->gadget)) { 381 loopback_driver.descriptors = otg_desc; 382 loopback_driver.bmAttributes |= USB_CONFIG_ATT_WAKEUP; 383 } 384 385 return usb_add_config(cdev, &loopback_driver); 386} 387