1/* 2 * <linux/usb/gadget.h> 3 * 4 * We call the USB code inside a Linux-based peripheral device a "gadget" 5 * driver, except for the hardware-specific bus glue. One USB host can 6 * master many USB gadgets, but the gadgets are only slaved to one host. 7 * 8 * 9 * (C) Copyright 2002-2004 by David Brownell 10 * All Rights Reserved. 11 * 12 * This software is licensed under the GNU GPL version 2. 13 */ 14 15#ifndef __LINUX_USB_GADGET_H 16#define __LINUX_USB_GADGET_H 17 18struct usb_ep; 19 20/** 21 * struct usb_request - describes one i/o request 22 * @buf: Buffer used for data. Always provide this; some controllers 23 * only use PIO, or don't use DMA for some endpoints. 24 * @dma: DMA address corresponding to 'buf'. If you don't set this 25 * field, and the usb controller needs one, it is responsible 26 * for mapping and unmapping the buffer. 27 * @length: Length of that data 28 * @no_interrupt: If true, hints that no completion irq is needed. 29 * Helpful sometimes with deep request queues that are handled 30 * directly by DMA controllers. 31 * @zero: If true, when writing data, makes the last packet be "short" 32 * by adding a zero length packet as needed; 33 * @short_not_ok: When reading data, makes short packets be 34 * treated as errors (queue stops advancing till cleanup). 35 * @complete: Function called when request completes, so this request and 36 * its buffer may be re-used. The function will always be called with 37 * interrupts disabled, and it must not sleep. 38 * Reads terminate with a short packet, or when the buffer fills, 39 * whichever comes first. When writes terminate, some data bytes 40 * will usually still be in flight (often in a hardware fifo). 41 * Errors (for reads or writes) stop the queue from advancing 42 * until the completion function returns, so that any transfers 43 * invalidated by the error may first be dequeued. 44 * @context: For use by the completion callback 45 * @list: For use by the gadget driver. 46 * @status: Reports completion code, zero or a negative errno. 47 * Normally, faults block the transfer queue from advancing until 48 * the completion callback returns. 49 * Code "-ESHUTDOWN" indicates completion caused by device disconnect, 50 * or when the driver disabled the endpoint. 51 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT 52 * transfers) this may be less than the requested length. If the 53 * short_not_ok flag is set, short reads are treated as errors 54 * even when status otherwise indicates successful completion. 55 * Note that for writes (IN transfers) some data bytes may still 56 * reside in a device-side FIFO when the request is reported as 57 * complete. 58 * 59 * These are allocated/freed through the endpoint they're used with. The 60 * hardware's driver can add extra per-request data to the memory it returns, 61 * which often avoids separate memory allocations (potential failures), 62 * later when the request is queued. 63 * 64 * Request flags affect request handling, such as whether a zero length 65 * packet is written (the "zero" flag), whether a short read should be 66 * treated as an error (blocking request queue advance, the "short_not_ok" 67 * flag), or hinting that an interrupt is not required (the "no_interrupt" 68 * flag, for use with deep request queues). 69 * 70 * Bulk endpoints can use any size buffers, and can also be used for interrupt 71 * transfers. interrupt-only endpoints can be much less functional. 72 * 73 * NOTE: this is analagous to 'struct urb' on the host side, except that 74 * it's thinner and promotes more pre-allocation. 75 */ 76 77struct usb_request { 78 void *buf; 79 unsigned length; 80 dma_addr_t dma; 81 82 unsigned no_interrupt:1; 83 unsigned zero:1; 84 unsigned short_not_ok:1; 85 86 void (*complete)(struct usb_ep *ep, 87 struct usb_request *req); 88 void *context; 89 struct list_head list; 90 91 int status; 92 unsigned actual; 93}; 94 95/*-------------------------------------------------------------------------*/ 96 97/* endpoint-specific parts of the api to the usb controller hardware. 98 * unlike the urb model, (de)multiplexing layers are not required. 99 * (so this api could slash overhead if used on the host side...) 100 * 101 * note that device side usb controllers commonly differ in how many 102 * endpoints they support, as well as their capabilities. 103 */ 104struct usb_ep_ops { 105 int (*enable) (struct usb_ep *ep, 106 const struct usb_endpoint_descriptor *desc); 107 int (*disable) (struct usb_ep *ep); 108 109 struct usb_request *(*alloc_request) (struct usb_ep *ep, 110 gfp_t gfp_flags); 111 void (*free_request) (struct usb_ep *ep, struct usb_request *req); 112 113 int (*queue) (struct usb_ep *ep, struct usb_request *req, 114 gfp_t gfp_flags); 115 int (*dequeue) (struct usb_ep *ep, struct usb_request *req); 116 117 int (*set_halt) (struct usb_ep *ep, int value); 118 int (*set_wedge) (struct usb_ep *ep); 119 120 int (*fifo_status) (struct usb_ep *ep); 121 void (*fifo_flush) (struct usb_ep *ep); 122}; 123 124/** 125 * struct usb_ep - device side representation of USB endpoint 126 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk" 127 * @ops: Function pointers used to access hardware-specific operations. 128 * @ep_list:the gadget's ep_list holds all of its endpoints 129 * @maxpacket:The maximum packet size used on this endpoint. The initial 130 * value can sometimes be reduced (hardware allowing), according to 131 * the endpoint descriptor used to configure the endpoint. 132 * @driver_data:for use by the gadget driver. all other fields are 133 * read-only to gadget drivers. 134 * 135 * the bus controller driver lists all the general purpose endpoints in 136 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list, 137 * and is accessed only in response to a driver setup() callback. 138 */ 139struct usb_ep { 140 void *driver_data; 141 142 const char *name; 143 const struct usb_ep_ops *ops; 144 struct list_head ep_list; 145 unsigned maxpacket:16; 146}; 147 148/*-------------------------------------------------------------------------*/ 149 150/** 151 * usb_ep_enable - configure endpoint, making it usable 152 * @ep:the endpoint being configured. may not be the endpoint named "ep0". 153 * drivers discover endpoints through the ep_list of a usb_gadget. 154 * @desc:descriptor for desired behavior. caller guarantees this pointer 155 * remains valid until the endpoint is disabled; the data byte order 156 * is little-endian (usb-standard). 157 * 158 * when configurations are set, or when interface settings change, the driver 159 * will enable or disable the relevant endpoints. while it is enabled, an 160 * endpoint may be used for i/o until the driver receives a disconnect() from 161 * the host or until the endpoint is disabled. 162 * 163 * the ep0 implementation (which calls this routine) must ensure that the 164 * hardware capabilities of each endpoint match the descriptor provided 165 * for it. for example, an endpoint named "ep2in-bulk" would be usable 166 * for interrupt transfers as well as bulk, but it likely couldn't be used 167 * for iso transfers or for endpoint 14. some endpoints are fully 168 * configurable, with more generic names like "ep-a". (remember that for 169 * USB, "in" means "towards the USB master".) 170 * 171 * returns zero, or a negative error code. 172 */ 173static inline int usb_ep_enable(struct usb_ep *ep, 174 const struct usb_endpoint_descriptor *desc) 175{ 176 return ep->ops->enable(ep, desc); 177} 178 179/** 180 * usb_ep_disable - endpoint is no longer usable 181 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". 182 * 183 * no other task may be using this endpoint when this is called. 184 * any pending and uncompleted requests will complete with status 185 * indicating disconnect (-ESHUTDOWN) before this call returns. 186 * gadget drivers must call usb_ep_enable() again before queueing 187 * requests to the endpoint. 188 * 189 * returns zero, or a negative error code. 190 */ 191static inline int usb_ep_disable(struct usb_ep *ep) 192{ 193 return ep->ops->disable(ep); 194} 195 196/** 197 * usb_ep_alloc_request - allocate a request object to use with this endpoint 198 * @ep:the endpoint to be used with with the request 199 * @gfp_flags:GFP_* flags to use 200 * 201 * Request objects must be allocated with this call, since they normally 202 * need controller-specific setup and may even need endpoint-specific 203 * resources such as allocation of DMA descriptors. 204 * Requests may be submitted with usb_ep_queue(), and receive a single 205 * completion callback. Free requests with usb_ep_free_request(), when 206 * they are no longer needed. 207 * 208 * Returns the request, or null if one could not be allocated. 209 */ 210static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, 211 gfp_t gfp_flags) 212{ 213 return ep->ops->alloc_request(ep, gfp_flags); 214} 215 216/** 217 * usb_ep_free_request - frees a request object 218 * @ep:the endpoint associated with the request 219 * @req:the request being freed 220 * 221 * Reverses the effect of usb_ep_alloc_request(). 222 * Caller guarantees the request is not queued, and that it will 223 * no longer be requeued (or otherwise used). 224 */ 225static inline void usb_ep_free_request(struct usb_ep *ep, 226 struct usb_request *req) 227{ 228 ep->ops->free_request(ep, req); 229} 230 231/** 232 * usb_ep_queue - queues (submits) an I/O request to an endpoint. 233 * @ep:the endpoint associated with the request 234 * @req:the request being submitted 235 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't 236 * pre-allocate all necessary memory with the request. 237 * 238 * This tells the device controller to perform the specified request through 239 * that endpoint (reading or writing a buffer). When the request completes, 240 * including being canceled by usb_ep_dequeue(), the request's completion 241 * routine is called to return the request to the driver. Any endpoint 242 * (except control endpoints like ep0) may have more than one transfer 243 * request queued; they complete in FIFO order. Once a gadget driver 244 * submits a request, that request may not be examined or modified until it 245 * is given back to that driver through the completion callback. 246 * 247 * Each request is turned into one or more packets. The controller driver 248 * never merges adjacent requests into the same packet. OUT transfers 249 * will sometimes use data that's already buffered in the hardware. 250 * Drivers can rely on the fact that the first byte of the request's buffer 251 * always corresponds to the first byte of some USB packet, for both 252 * IN and OUT transfers. 253 * 254 * Bulk endpoints can queue any amount of data; the transfer is packetized 255 * automatically. The last packet will be short if the request doesn't fill it 256 * out completely. Zero length packets (ZLPs) should be avoided in portable 257 * protocols since not all usb hardware can successfully handle zero length 258 * packets. (ZLPs may be explicitly written, and may be implicitly written if 259 * the request 'zero' flag is set.) Bulk endpoints may also be used 260 * for interrupt transfers; but the reverse is not true, and some endpoints 261 * won't support every interrupt transfer. (Such as 768 byte packets.) 262 * 263 * Interrupt-only endpoints are less functional than bulk endpoints, for 264 * example by not supporting queueing or not handling buffers that are 265 * larger than the endpoint's maxpacket size. They may also treat data 266 * toggle differently. 267 * 268 * Control endpoints ... after getting a setup() callback, the driver queues 269 * one response (even if it would be zero length). That enables the 270 * status ack, after transfering data as specified in the response. Setup 271 * functions may return negative error codes to generate protocol stalls. 272 * (Note that some USB device controllers disallow protocol stall responses 273 * in some cases.) When control responses are deferred (the response is 274 * written after the setup callback returns), then usb_ep_set_halt() may be 275 * used on ep0 to trigger protocol stalls. Depending on the controller, 276 * it may not be possible to trigger a status-stage protocol stall when the 277 * data stage is over, that is, from within the response's completion 278 * routine. 279 * 280 * For periodic endpoints, like interrupt or isochronous ones, the usb host 281 * arranges to poll once per interval, and the gadget driver usually will 282 * have queued some data to transfer at that time. 283 * 284 * Returns zero, or a negative error code. Endpoints that are not enabled 285 * report errors; errors will also be 286 * reported when the usb peripheral is disconnected. 287 */ 288static inline int usb_ep_queue(struct usb_ep *ep, 289 struct usb_request *req, gfp_t gfp_flags) 290{ 291 return ep->ops->queue(ep, req, gfp_flags); 292} 293 294/** 295 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint 296 * @ep:the endpoint associated with the request 297 * @req:the request being canceled 298 * 299 * if the request is still active on the endpoint, it is dequeued and its 300 * completion routine is called (with status -ECONNRESET); else a negative 301 * error code is returned. 302 * 303 * note that some hardware can't clear out write fifos (to unlink the request 304 * at the head of the queue) except as part of disconnecting from usb. such 305 * restrictions prevent drivers from supporting configuration changes, 306 * even to configuration zero (a "chapter 9" requirement). 307 */ 308static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req) 309{ 310 return ep->ops->dequeue(ep, req); 311} 312 313/** 314 * usb_ep_set_halt - sets the endpoint halt feature. 315 * @ep: the non-isochronous endpoint being stalled 316 * 317 * Use this to stall an endpoint, perhaps as an error report. 318 * Except for control endpoints, 319 * the endpoint stays halted (will not stream any data) until the host 320 * clears this feature; drivers may need to empty the endpoint's request 321 * queue first, to make sure no inappropriate transfers happen. 322 * 323 * Note that while an endpoint CLEAR_FEATURE will be invisible to the 324 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the 325 * current altsetting, see usb_ep_clear_halt(). When switching altsettings, 326 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. 327 * 328 * Returns zero, or a negative error code. On success, this call sets 329 * underlying hardware state that blocks data transfers. 330 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any 331 * transfer requests are still queued, or if the controller hardware 332 * (usually a FIFO) still holds bytes that the host hasn't collected. 333 */ 334static inline int usb_ep_set_halt(struct usb_ep *ep) 335{ 336 return ep->ops->set_halt(ep, 1); 337} 338 339/** 340 * usb_ep_clear_halt - clears endpoint halt, and resets toggle 341 * @ep:the bulk or interrupt endpoint being reset 342 * 343 * Use this when responding to the standard usb "set interface" request, 344 * for endpoints that aren't reconfigured, after clearing any other state 345 * in the endpoint's i/o queue. 346 * 347 * Returns zero, or a negative error code. On success, this call clears 348 * the underlying hardware state reflecting endpoint halt and data toggle. 349 * Note that some hardware can't support this request (like pxa2xx_udc), 350 * and accordingly can't correctly implement interface altsettings. 351 */ 352static inline int usb_ep_clear_halt(struct usb_ep *ep) 353{ 354 return ep->ops->set_halt(ep, 0); 355} 356 357/** 358 * usb_ep_set_wedge - sets the halt feature and ignores clear requests 359 * @ep: the endpoint being wedged 360 * 361 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT) 362 * requests. If the gadget driver clears the halt status, it will 363 * automatically unwedge the endpoint. 364 * 365 * Returns zero on success, else negative errno. 366 */ 367static inline int 368usb_ep_set_wedge(struct usb_ep *ep) 369{ 370 if (ep->ops->set_wedge) 371 return ep->ops->set_wedge(ep); 372 else 373 return ep->ops->set_halt(ep, 1); 374} 375 376/** 377 * usb_ep_fifo_status - returns number of bytes in fifo, or error 378 * @ep: the endpoint whose fifo status is being checked. 379 * 380 * FIFO endpoints may have "unclaimed data" in them in certain cases, 381 * such as after aborted transfers. Hosts may not have collected all 382 * the IN data written by the gadget driver (and reported by a request 383 * completion). The gadget driver may not have collected all the data 384 * written OUT to it by the host. Drivers that need precise handling for 385 * fault reporting or recovery may need to use this call. 386 * 387 * This returns the number of such bytes in the fifo, or a negative 388 * errno if the endpoint doesn't use a FIFO or doesn't support such 389 * precise handling. 390 */ 391static inline int usb_ep_fifo_status(struct usb_ep *ep) 392{ 393 if (ep->ops->fifo_status) 394 return ep->ops->fifo_status(ep); 395 else 396 return -EOPNOTSUPP; 397} 398 399/** 400 * usb_ep_fifo_flush - flushes contents of a fifo 401 * @ep: the endpoint whose fifo is being flushed. 402 * 403 * This call may be used to flush the "unclaimed data" that may exist in 404 * an endpoint fifo after abnormal transaction terminations. The call 405 * must never be used except when endpoint is not being used for any 406 * protocol translation. 407 */ 408static inline void usb_ep_fifo_flush(struct usb_ep *ep) 409{ 410 if (ep->ops->fifo_flush) 411 ep->ops->fifo_flush(ep); 412} 413 414 415/*-------------------------------------------------------------------------*/ 416 417struct usb_gadget; 418 419/* the rest of the api to the controller hardware: device operations, 420 * which don't involve endpoints (or i/o). 421 */ 422struct usb_gadget_ops { 423 int (*get_frame)(struct usb_gadget *); 424 int (*wakeup)(struct usb_gadget *); 425 int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered); 426 int (*vbus_session) (struct usb_gadget *, int is_active); 427 int (*vbus_draw) (struct usb_gadget *, unsigned mA); 428 int (*pullup) (struct usb_gadget *, int is_on); 429 int (*ioctl)(struct usb_gadget *, 430 unsigned code, unsigned long param); 431}; 432 433/** 434 * struct usb_gadget - represents a usb slave device 435 * @ops: Function pointers used to access hardware-specific operations. 436 * @ep0: Endpoint zero, used when reading or writing responses to 437 * driver setup() requests 438 * @ep_list: List of other endpoints supported by the device. 439 * @speed: Speed of current connection to USB host. 440 * @is_dualspeed: True if the controller supports both high and full speed 441 * operation. If it does, the gadget driver must also support both. 442 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the 443 * gadget driver must provide a USB OTG descriptor. 444 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable 445 * is in the Mini-AB jack, and HNP has been used to switch roles 446 * so that the "A" device currently acts as A-Peripheral, not A-Host. 447 * @a_hnp_support: OTG device feature flag, indicating that the A-Host 448 * supports HNP at this port. 449 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host 450 * only supports HNP on a different root port. 451 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host 452 * enabled HNP support. 453 * @name: Identifies the controller hardware type. Used in diagnostics 454 * and sometimes configuration. 455 * @dev: Driver model state for this abstract device. 456 * 457 * Gadgets have a mostly-portable "gadget driver" implementing device 458 * functions, handling all usb configurations and interfaces. Gadget 459 * drivers talk to hardware-specific code indirectly, through ops vectors. 460 * That insulates the gadget driver from hardware details, and packages 461 * the hardware endpoints through generic i/o queues. The "usb_gadget" 462 * and "usb_ep" interfaces provide that insulation from the hardware. 463 * 464 * Except for the driver data, all fields in this structure are 465 * read-only to the gadget driver. That driver data is part of the 466 * "driver model" infrastructure in 2.6 (and later) kernels, and for 467 * earlier systems is grouped in a similar structure that's not known 468 * to the rest of the kernel. 469 * 470 * Values of the three OTG device feature flags are updated before the 471 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before 472 * driver suspend() calls. They are valid only when is_otg, and when the 473 * device is acting as a B-Peripheral (so is_a_peripheral is false). 474 */ 475struct usb_gadget { 476 /* readonly to gadget driver */ 477 const struct usb_gadget_ops *ops; 478 struct usb_ep *ep0; 479 struct list_head ep_list; /* of usb_ep */ 480 enum usb_device_speed speed; 481 unsigned is_dualspeed:1; 482 unsigned is_otg:1; 483 unsigned is_a_peripheral:1; 484 unsigned b_hnp_enable:1; 485 unsigned a_hnp_support:1; 486 unsigned a_alt_hnp_support:1; 487 const char *name; 488 struct device dev; 489}; 490 491static inline void set_gadget_data(struct usb_gadget *gadget, void *data) 492 { dev_set_drvdata(&gadget->dev, data); } 493static inline void *get_gadget_data(struct usb_gadget *gadget) 494 { return dev_get_drvdata(&gadget->dev); } 495 496/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */ 497#define gadget_for_each_ep(tmp,gadget) \ 498 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list) 499 500 501/** 502 * gadget_is_dualspeed - return true iff the hardware handles high speed 503 * @g: controller that might support both high and full speeds 504 */ 505static inline int gadget_is_dualspeed(struct usb_gadget *g) 506{ 507#ifdef CONFIG_USB_GADGET_DUALSPEED 508 /* runtime test would check "g->is_dualspeed" ... that might be 509 * useful to work around hardware bugs, but is mostly pointless 510 */ 511 return 1; 512#else 513 return 0; 514#endif 515} 516 517/** 518 * gadget_is_otg - return true iff the hardware is OTG-ready 519 * @g: controller that might have a Mini-AB connector 520 * 521 * This is a runtime test, since kernels with a USB-OTG stack sometimes 522 * run on boards which only have a Mini-B (or Mini-A) connector. 523 */ 524static inline int gadget_is_otg(struct usb_gadget *g) 525{ 526#ifdef CONFIG_USB_OTG 527 return g->is_otg; 528#else 529 return 0; 530#endif 531} 532 533/** 534 * usb_gadget_frame_number - returns the current frame number 535 * @gadget: controller that reports the frame number 536 * 537 * Returns the usb frame number, normally eleven bits from a SOF packet, 538 * or negative errno if this device doesn't support this capability. 539 */ 540static inline int usb_gadget_frame_number(struct usb_gadget *gadget) 541{ 542 return gadget->ops->get_frame(gadget); 543} 544 545/** 546 * usb_gadget_wakeup - tries to wake up the host connected to this gadget 547 * @gadget: controller used to wake up the host 548 * 549 * Returns zero on success, else negative error code if the hardware 550 * doesn't support such attempts, or its support has not been enabled 551 * by the usb host. Drivers must return device descriptors that report 552 * their ability to support this, or hosts won't enable it. 553 * 554 * This may also try to use SRP to wake the host and start enumeration, 555 * even if OTG isn't otherwise in use. OTG devices may also start 556 * remote wakeup even when hosts don't explicitly enable it. 557 */ 558static inline int usb_gadget_wakeup(struct usb_gadget *gadget) 559{ 560 if (!gadget->ops->wakeup) 561 return -EOPNOTSUPP; 562 return gadget->ops->wakeup(gadget); 563} 564 565/** 566 * usb_gadget_set_selfpowered - sets the device selfpowered feature. 567 * @gadget:the device being declared as self-powered 568 * 569 * this affects the device status reported by the hardware driver 570 * to reflect that it now has a local power supply. 571 * 572 * returns zero on success, else negative errno. 573 */ 574static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget) 575{ 576 if (!gadget->ops->set_selfpowered) 577 return -EOPNOTSUPP; 578 return gadget->ops->set_selfpowered(gadget, 1); 579} 580 581/** 582 * usb_gadget_clear_selfpowered - clear the device selfpowered feature. 583 * @gadget:the device being declared as bus-powered 584 * 585 * this affects the device status reported by the hardware driver. 586 * some hardware may not support bus-powered operation, in which 587 * case this feature's value can never change. 588 * 589 * returns zero on success, else negative errno. 590 */ 591static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget) 592{ 593 if (!gadget->ops->set_selfpowered) 594 return -EOPNOTSUPP; 595 return gadget->ops->set_selfpowered(gadget, 0); 596} 597 598/** 599 * usb_gadget_vbus_connect - Notify controller that VBUS is powered 600 * @gadget:The device which now has VBUS power. 601 * Context: can sleep 602 * 603 * This call is used by a driver for an external transceiver (or GPIO) 604 * that detects a VBUS power session starting. Common responses include 605 * resuming the controller, activating the D+ (or D-) pullup to let the 606 * host detect that a USB device is attached, and starting to draw power 607 * (8mA or possibly more, especially after SET_CONFIGURATION). 608 * 609 * Returns zero on success, else negative errno. 610 */ 611static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget) 612{ 613 if (!gadget->ops->vbus_session) 614 return -EOPNOTSUPP; 615 return gadget->ops->vbus_session(gadget, 1); 616} 617 618/** 619 * usb_gadget_vbus_draw - constrain controller's VBUS power usage 620 * @gadget:The device whose VBUS usage is being described 621 * @mA:How much current to draw, in milliAmperes. This should be twice 622 * the value listed in the configuration descriptor bMaxPower field. 623 * 624 * This call is used by gadget drivers during SET_CONFIGURATION calls, 625 * reporting how much power the device may consume. For example, this 626 * could affect how quickly batteries are recharged. 627 * 628 * Returns zero on success, else negative errno. 629 */ 630static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA) 631{ 632 if (!gadget->ops->vbus_draw) 633 return -EOPNOTSUPP; 634 return gadget->ops->vbus_draw(gadget, mA); 635} 636 637/** 638 * usb_gadget_vbus_disconnect - notify controller about VBUS session end 639 * @gadget:the device whose VBUS supply is being described 640 * Context: can sleep 641 * 642 * This call is used by a driver for an external transceiver (or GPIO) 643 * that detects a VBUS power session ending. Common responses include 644 * reversing everything done in usb_gadget_vbus_connect(). 645 * 646 * Returns zero on success, else negative errno. 647 */ 648static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) 649{ 650 if (!gadget->ops->vbus_session) 651 return -EOPNOTSUPP; 652 return gadget->ops->vbus_session(gadget, 0); 653} 654 655/** 656 * usb_gadget_connect - software-controlled connect to USB host 657 * @gadget:the peripheral being connected 658 * 659 * Enables the D+ (or potentially D-) pullup. The host will start 660 * enumerating this gadget when the pullup is active and a VBUS session 661 * is active (the link is powered). This pullup is always enabled unless 662 * usb_gadget_disconnect() has been used to disable it. 663 * 664 * Returns zero on success, else negative errno. 665 */ 666static inline int usb_gadget_connect(struct usb_gadget *gadget) 667{ 668 if (!gadget->ops->pullup) 669 return -EOPNOTSUPP; 670 return gadget->ops->pullup(gadget, 1); 671} 672 673/** 674 * usb_gadget_disconnect - software-controlled disconnect from USB host 675 * @gadget:the peripheral being disconnected 676 * 677 * Disables the D+ (or potentially D-) pullup, which the host may see 678 * as a disconnect (when a VBUS session is active). Not all systems 679 * support software pullup controls. 680 * 681 * This routine may be used during the gadget driver bind() call to prevent 682 * the peripheral from ever being visible to the USB host, unless later 683 * usb_gadget_connect() is called. For example, user mode components may 684 * need to be activated before the system can talk to hosts. 685 * 686 * Returns zero on success, else negative errno. 687 */ 688static inline int usb_gadget_disconnect(struct usb_gadget *gadget) 689{ 690 if (!gadget->ops->pullup) 691 return -EOPNOTSUPP; 692 return gadget->ops->pullup(gadget, 0); 693} 694 695 696/*-------------------------------------------------------------------------*/ 697 698/** 699 * struct usb_gadget_driver - driver for usb 'slave' devices 700 * @function: String describing the gadget's function 701 * @speed: Highest speed the driver handles. 702 * @bind: Invoked when the driver is bound to a gadget, usually 703 * after registering the driver. 704 * At that point, ep0 is fully initialized, and ep_list holds 705 * the currently-available endpoints. 706 * Called in a context that permits sleeping. 707 * @setup: Invoked for ep0 control requests that aren't handled by 708 * the hardware level driver. Most calls must be handled by 709 * the gadget driver, including descriptor and configuration 710 * management. The 16 bit members of the setup data are in 711 * USB byte order. Called in_interrupt; this may not sleep. Driver 712 * queues a response to ep0, or returns negative to stall. 713 * @disconnect: Invoked after all transfers have been stopped, 714 * when the host is disconnected. May be called in_interrupt; this 715 * may not sleep. Some devices can't detect disconnect, so this might 716 * not be called except as part of controller shutdown. 717 * @unbind: Invoked when the driver is unbound from a gadget, 718 * usually from rmmod (after a disconnect is reported). 719 * Called in a context that permits sleeping. 720 * @suspend: Invoked on USB suspend. May be called in_interrupt. 721 * @resume: Invoked on USB resume. May be called in_interrupt. 722 * @driver: Driver model state for this driver. 723 * 724 * Devices are disabled till a gadget driver successfully bind()s, which 725 * means the driver will handle setup() requests needed to enumerate (and 726 * meet "chapter 9" requirements) then do some useful work. 727 * 728 * If gadget->is_otg is true, the gadget driver must provide an OTG 729 * descriptor during enumeration, or else fail the bind() call. In such 730 * cases, no USB traffic may flow until both bind() returns without 731 * having called usb_gadget_disconnect(), and the USB host stack has 732 * initialized. 733 * 734 * Drivers use hardware-specific knowledge to configure the usb hardware. 735 * endpoint addressing is only one of several hardware characteristics that 736 * are in descriptors the ep0 implementation returns from setup() calls. 737 * 738 * Except for ep0 implementation, most driver code shouldn't need change to 739 * run on top of different usb controllers. It'll use endpoints set up by 740 * that ep0 implementation. 741 * 742 * The usb controller driver handles a few standard usb requests. Those 743 * include set_address, and feature flags for devices, interfaces, and 744 * endpoints (the get_status, set_feature, and clear_feature requests). 745 * 746 * Accordingly, the driver's setup() callback must always implement all 747 * get_descriptor requests, returning at least a device descriptor and 748 * a configuration descriptor. Drivers must make sure the endpoint 749 * descriptors match any hardware constraints. Some hardware also constrains 750 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3). 751 * 752 * The driver's setup() callback must also implement set_configuration, 753 * and should also implement set_interface, get_configuration, and 754 * get_interface. Setting a configuration (or interface) is where 755 * endpoints should be activated or (config 0) shut down. 756 * 757 * (Note that only the default control endpoint is supported. Neither 758 * hosts nor devices generally support control traffic except to ep0.) 759 * 760 * Most devices will ignore USB suspend/resume operations, and so will 761 * not provide those callbacks. However, some may need to change modes 762 * when the host is not longer directing those activities. For example, 763 * local controls (buttons, dials, etc) may need to be re-enabled since 764 * the (remote) host can't do that any longer; or an error state might 765 * be cleared, to make the device behave identically whether or not 766 * power is maintained. 767 */ 768struct usb_gadget_driver { 769 char *function; 770 enum usb_device_speed speed; 771 int (*bind)(struct usb_gadget *); 772 void (*unbind)(struct usb_gadget *); 773 int (*setup)(struct usb_gadget *, 774 const struct usb_ctrlrequest *); 775 void (*disconnect)(struct usb_gadget *); 776 void (*suspend)(struct usb_gadget *); 777 void (*resume)(struct usb_gadget *); 778 779 /* FIXME support safe rmmod */ 780 struct device_driver driver; 781}; 782 783 784 785/*-------------------------------------------------------------------------*/ 786 787/* driver modules register and unregister, as usual. 788 * these calls must be made in a context that can sleep. 789 * 790 * these will usually be implemented directly by the hardware-dependent 791 * usb bus interface driver, which will only support a single driver. 792 */ 793 794/** 795 * usb_gadget_register_driver - register a gadget driver 796 * @driver:the driver being registered 797 * Context: can sleep 798 * 799 * Call this in your gadget driver's module initialization function, 800 * to tell the underlying usb controller driver about your driver. 801 * The driver's bind() function will be called to bind it to a 802 * gadget before this registration call returns. It's expected that 803 * the bind() functions will be in init sections. 804 */ 805int usb_gadget_register_driver(struct usb_gadget_driver *driver); 806 807/** 808 * usb_gadget_unregister_driver - unregister a gadget driver 809 * @driver:the driver being unregistered 810 * Context: can sleep 811 * 812 * Call this in your gadget driver's module cleanup function, 813 * to tell the underlying usb controller that your driver is 814 * going away. If the controller is connected to a USB host, 815 * it will first disconnect(). The driver is also requested 816 * to unbind() and clean up any device state, before this procedure 817 * finally returns. It's expected that the unbind() functions 818 * will in in exit sections, so may not be linked in some kernels. 819 */ 820int usb_gadget_unregister_driver(struct usb_gadget_driver *driver); 821 822/*-------------------------------------------------------------------------*/ 823 824/* utility to simplify dealing with string descriptors */ 825 826/** 827 * struct usb_string - wraps a C string and its USB id 828 * @id:the (nonzero) ID for this string 829 * @s:the string, in UTF-8 encoding 830 * 831 * If you're using usb_gadget_get_string(), use this to wrap a string 832 * together with its ID. 833 */ 834struct usb_string { 835 u8 id; 836 const char *s; 837}; 838 839/** 840 * struct usb_gadget_strings - a set of USB strings in a given language 841 * @language:identifies the strings' language (0x0409 for en-us) 842 * @strings:array of strings with their ids 843 * 844 * If you're using usb_gadget_get_string(), use this to wrap all the 845 * strings for a given language. 846 */ 847struct usb_gadget_strings { 848 u16 language; /* 0x0409 for en-us */ 849 struct usb_string *strings; 850}; 851 852/* put descriptor for string with that id into buf (buflen >= 256) */ 853int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf); 854 855/*-------------------------------------------------------------------------*/ 856 857/* utility to simplify managing config descriptors */ 858 859/* write vector of descriptors into buffer */ 860int usb_descriptor_fillbuf(void *, unsigned, 861 const struct usb_descriptor_header **); 862 863/* build config descriptor from single descriptor vector */ 864int usb_gadget_config_buf(const struct usb_config_descriptor *config, 865 void *buf, unsigned buflen, const struct usb_descriptor_header **desc); 866 867/* copy a NULL-terminated vector of descriptors */ 868struct usb_descriptor_header **usb_copy_descriptors( 869 struct usb_descriptor_header **); 870 871/* return copy of endpoint descriptor given original descriptor set */ 872struct usb_endpoint_descriptor *usb_find_endpoint( 873 struct usb_descriptor_header **src, 874 struct usb_descriptor_header **copy, 875 struct usb_endpoint_descriptor *match); 876 877/** 878 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors() 879 * @v: vector of descriptors 880 */ 881static inline void usb_free_descriptors(struct usb_descriptor_header **v) 882{ 883 kfree(v); 884} 885 886/*-------------------------------------------------------------------------*/ 887 888/* utility wrapping a simple endpoint selection policy */ 889 890extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *, 891 struct usb_endpoint_descriptor *) __devinit; 892 893extern void usb_ep_autoconfig_reset(struct usb_gadget *) __devinit; 894 895#endif /* __LINUX_USB_GADGET_H */ 896