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 18#include <linux/slab.h> 19 20struct usb_ep; 21 22/** 23 * struct usb_request - describes one i/o request 24 * @buf: Buffer used for data. Always provide this; some controllers 25 * only use PIO, or don't use DMA for some endpoints. 26 * @dma: DMA address corresponding to 'buf'. If you don't set this 27 * field, and the usb controller needs one, it is responsible 28 * for mapping and unmapping the buffer. 29 * @length: Length of that data 30 * @no_interrupt: If true, hints that no completion irq is needed. 31 * Helpful sometimes with deep request queues that are handled 32 * directly by DMA controllers. 33 * @zero: If true, when writing data, makes the last packet be "short" 34 * by adding a zero length packet as needed; 35 * @short_not_ok: When reading data, makes short packets be 36 * treated as errors (queue stops advancing till cleanup). 37 * @complete: Function called when request completes, so this request and 38 * its buffer may be re-used. The function will always be called with 39 * interrupts disabled, and it must not sleep. 40 * Reads terminate with a short packet, or when the buffer fills, 41 * whichever comes first. When writes terminate, some data bytes 42 * will usually still be in flight (often in a hardware fifo). 43 * Errors (for reads or writes) stop the queue from advancing 44 * until the completion function returns, so that any transfers 45 * invalidated by the error may first be dequeued. 46 * @context: For use by the completion callback 47 * @list: For use by the gadget driver. 48 * @status: Reports completion code, zero or a negative errno. 49 * Normally, faults block the transfer queue from advancing until 50 * the completion callback returns. 51 * Code "-ESHUTDOWN" indicates completion caused by device disconnect, 52 * or when the driver disabled the endpoint. 53 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT 54 * transfers) this may be less than the requested length. If the 55 * short_not_ok flag is set, short reads are treated as errors 56 * even when status otherwise indicates successful completion. 57 * Note that for writes (IN transfers) some data bytes may still 58 * reside in a device-side FIFO when the request is reported as 59 * complete. 60 * 61 * These are allocated/freed through the endpoint they're used with. The 62 * hardware's driver can add extra per-request data to the memory it returns, 63 * which often avoids separate memory allocations (potential failures), 64 * later when the request is queued. 65 * 66 * Request flags affect request handling, such as whether a zero length 67 * packet is written (the "zero" flag), whether a short read should be 68 * treated as an error (blocking request queue advance, the "short_not_ok" 69 * flag), or hinting that an interrupt is not required (the "no_interrupt" 70 * flag, for use with deep request queues). 71 * 72 * Bulk endpoints can use any size buffers, and can also be used for interrupt 73 * transfers. interrupt-only endpoints can be much less functional. 74 * 75 * NOTE: this is analagous to 'struct urb' on the host side, except that 76 * it's thinner and promotes more pre-allocation. 77 */ 78 79struct usb_request { 80 void *buf; 81 unsigned length; 82 dma_addr_t dma; 83 84 unsigned no_interrupt:1; 85 unsigned zero:1; 86 unsigned short_not_ok:1; 87 88 void (*complete)(struct usb_ep *ep, 89 struct usb_request *req); 90 void *context; 91 struct list_head list; 92 93 int status; 94 unsigned actual; 95}; 96 97/*-------------------------------------------------------------------------*/ 98 99/* endpoint-specific parts of the api to the usb controller hardware. 100 * unlike the urb model, (de)multiplexing layers are not required. 101 * (so this api could slash overhead if used on the host side...) 102 * 103 * note that device side usb controllers commonly differ in how many 104 * endpoints they support, as well as their capabilities. 105 */ 106struct usb_ep_ops { 107 int (*enable) (struct usb_ep *ep, 108 const struct usb_endpoint_descriptor *desc); 109 int (*disable) (struct usb_ep *ep); 110 111 struct usb_request *(*alloc_request) (struct usb_ep *ep, 112 gfp_t gfp_flags); 113 void (*free_request) (struct usb_ep *ep, struct usb_request *req); 114 115 int (*queue) (struct usb_ep *ep, struct usb_request *req, 116 gfp_t gfp_flags); 117 int (*dequeue) (struct usb_ep *ep, struct usb_request *req); 118 119 int (*set_halt) (struct usb_ep *ep, int value); 120 int (*set_wedge) (struct usb_ep *ep); 121 122 int (*fifo_status) (struct usb_ep *ep); 123 void (*fifo_flush) (struct usb_ep *ep); 124}; 125 126/** 127 * struct usb_ep - device side representation of USB endpoint 128 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk" 129 * @ops: Function pointers used to access hardware-specific operations. 130 * @ep_list:the gadget's ep_list holds all of its endpoints 131 * @maxpacket:The maximum packet size used on this endpoint. The initial 132 * value can sometimes be reduced (hardware allowing), according to 133 * the endpoint descriptor used to configure the endpoint. 134 * @driver_data:for use by the gadget driver. all other fields are 135 * read-only to gadget drivers. 136 * 137 * the bus controller driver lists all the general purpose endpoints in 138 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list, 139 * and is accessed only in response to a driver setup() callback. 140 */ 141struct usb_ep { 142 void *driver_data; 143 144 const char *name; 145 const struct usb_ep_ops *ops; 146 struct list_head ep_list; 147 unsigned maxpacket:16; 148}; 149 150/*-------------------------------------------------------------------------*/ 151 152/** 153 * usb_ep_enable - configure endpoint, making it usable 154 * @ep:the endpoint being configured. may not be the endpoint named "ep0". 155 * drivers discover endpoints through the ep_list of a usb_gadget. 156 * @desc:descriptor for desired behavior. caller guarantees this pointer 157 * remains valid until the endpoint is disabled; the data byte order 158 * is little-endian (usb-standard). 159 * 160 * when configurations are set, or when interface settings change, the driver 161 * will enable or disable the relevant endpoints. while it is enabled, an 162 * endpoint may be used for i/o until the driver receives a disconnect() from 163 * the host or until the endpoint is disabled. 164 * 165 * the ep0 implementation (which calls this routine) must ensure that the 166 * hardware capabilities of each endpoint match the descriptor provided 167 * for it. for example, an endpoint named "ep2in-bulk" would be usable 168 * for interrupt transfers as well as bulk, but it likely couldn't be used 169 * for iso transfers or for endpoint 14. some endpoints are fully 170 * configurable, with more generic names like "ep-a". (remember that for 171 * USB, "in" means "towards the USB master".) 172 * 173 * returns zero, or a negative error code. 174 */ 175static inline int usb_ep_enable(struct usb_ep *ep, 176 const struct usb_endpoint_descriptor *desc) 177{ 178 return ep->ops->enable(ep, desc); 179} 180 181/** 182 * usb_ep_disable - endpoint is no longer usable 183 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". 184 * 185 * no other task may be using this endpoint when this is called. 186 * any pending and uncompleted requests will complete with status 187 * indicating disconnect (-ESHUTDOWN) before this call returns. 188 * gadget drivers must call usb_ep_enable() again before queueing 189 * requests to the endpoint. 190 * 191 * returns zero, or a negative error code. 192 */ 193static inline int usb_ep_disable(struct usb_ep *ep) 194{ 195 return ep->ops->disable(ep); 196} 197 198/** 199 * usb_ep_alloc_request - allocate a request object to use with this endpoint 200 * @ep:the endpoint to be used with with the request 201 * @gfp_flags:GFP_* flags to use 202 * 203 * Request objects must be allocated with this call, since they normally 204 * need controller-specific setup and may even need endpoint-specific 205 * resources such as allocation of DMA descriptors. 206 * Requests may be submitted with usb_ep_queue(), and receive a single 207 * completion callback. Free requests with usb_ep_free_request(), when 208 * they are no longer needed. 209 * 210 * Returns the request, or null if one could not be allocated. 211 */ 212static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, 213 gfp_t gfp_flags) 214{ 215 return ep->ops->alloc_request(ep, gfp_flags); 216} 217 218/** 219 * usb_ep_free_request - frees a request object 220 * @ep:the endpoint associated with the request 221 * @req:the request being freed 222 * 223 * Reverses the effect of usb_ep_alloc_request(). 224 * Caller guarantees the request is not queued, and that it will 225 * no longer be requeued (or otherwise used). 226 */ 227static inline void usb_ep_free_request(struct usb_ep *ep, 228 struct usb_request *req) 229{ 230 ep->ops->free_request(ep, req); 231} 232 233/** 234 * usb_ep_queue - queues (submits) an I/O request to an endpoint. 235 * @ep:the endpoint associated with the request 236 * @req:the request being submitted 237 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't 238 * pre-allocate all necessary memory with the request. 239 * 240 * This tells the device controller to perform the specified request through 241 * that endpoint (reading or writing a buffer). When the request completes, 242 * including being canceled by usb_ep_dequeue(), the request's completion 243 * routine is called to return the request to the driver. Any endpoint 244 * (except control endpoints like ep0) may have more than one transfer 245 * request queued; they complete in FIFO order. Once a gadget driver 246 * submits a request, that request may not be examined or modified until it 247 * is given back to that driver through the completion callback. 248 * 249 * Each request is turned into one or more packets. The controller driver 250 * never merges adjacent requests into the same packet. OUT transfers 251 * will sometimes use data that's already buffered in the hardware. 252 * Drivers can rely on the fact that the first byte of the request's buffer 253 * always corresponds to the first byte of some USB packet, for both 254 * IN and OUT transfers. 255 * 256 * Bulk endpoints can queue any amount of data; the transfer is packetized 257 * automatically. The last packet will be short if the request doesn't fill it 258 * out completely. Zero length packets (ZLPs) should be avoided in portable 259 * protocols since not all usb hardware can successfully handle zero length 260 * packets. (ZLPs may be explicitly written, and may be implicitly written if 261 * the request 'zero' flag is set.) Bulk endpoints may also be used 262 * for interrupt transfers; but the reverse is not true, and some endpoints 263 * won't support every interrupt transfer. (Such as 768 byte packets.) 264 * 265 * Interrupt-only endpoints are less functional than bulk endpoints, for 266 * example by not supporting queueing or not handling buffers that are 267 * larger than the endpoint's maxpacket size. They may also treat data 268 * toggle differently. 269 * 270 * Control endpoints ... after getting a setup() callback, the driver queues 271 * one response (even if it would be zero length). That enables the 272 * status ack, after transfering data as specified in the response. Setup 273 * functions may return negative error codes to generate protocol stalls. 274 * (Note that some USB device controllers disallow protocol stall responses 275 * in some cases.) When control responses are deferred (the response is 276 * written after the setup callback returns), then usb_ep_set_halt() may be 277 * used on ep0 to trigger protocol stalls. Depending on the controller, 278 * it may not be possible to trigger a status-stage protocol stall when the 279 * data stage is over, that is, from within the response's completion 280 * routine. 281 * 282 * For periodic endpoints, like interrupt or isochronous ones, the usb host 283 * arranges to poll once per interval, and the gadget driver usually will 284 * have queued some data to transfer at that time. 285 * 286 * Returns zero, or a negative error code. Endpoints that are not enabled 287 * report errors; errors will also be 288 * reported when the usb peripheral is disconnected. 289 */ 290static inline int usb_ep_queue(struct usb_ep *ep, 291 struct usb_request *req, gfp_t gfp_flags) 292{ 293 return ep->ops->queue(ep, req, gfp_flags); 294} 295 296/** 297 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint 298 * @ep:the endpoint associated with the request 299 * @req:the request being canceled 300 * 301 * if the request is still active on the endpoint, it is dequeued and its 302 * completion routine is called (with status -ECONNRESET); else a negative 303 * error code is returned. 304 * 305 * note that some hardware can't clear out write fifos (to unlink the request 306 * at the head of the queue) except as part of disconnecting from usb. such 307 * restrictions prevent drivers from supporting configuration changes, 308 * even to configuration zero (a "chapter 9" requirement). 309 */ 310static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req) 311{ 312 return ep->ops->dequeue(ep, req); 313} 314 315/** 316 * usb_ep_set_halt - sets the endpoint halt feature. 317 * @ep: the non-isochronous endpoint being stalled 318 * 319 * Use this to stall an endpoint, perhaps as an error report. 320 * Except for control endpoints, 321 * the endpoint stays halted (will not stream any data) until the host 322 * clears this feature; drivers may need to empty the endpoint's request 323 * queue first, to make sure no inappropriate transfers happen. 324 * 325 * Note that while an endpoint CLEAR_FEATURE will be invisible to the 326 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the 327 * current altsetting, see usb_ep_clear_halt(). When switching altsettings, 328 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. 329 * 330 * Returns zero, or a negative error code. On success, this call sets 331 * underlying hardware state that blocks data transfers. 332 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any 333 * transfer requests are still queued, or if the controller hardware 334 * (usually a FIFO) still holds bytes that the host hasn't collected. 335 */ 336static inline int usb_ep_set_halt(struct usb_ep *ep) 337{ 338 return ep->ops->set_halt(ep, 1); 339} 340 341/** 342 * usb_ep_clear_halt - clears endpoint halt, and resets toggle 343 * @ep:the bulk or interrupt endpoint being reset 344 * 345 * Use this when responding to the standard usb "set interface" request, 346 * for endpoints that aren't reconfigured, after clearing any other state 347 * in the endpoint's i/o queue. 348 * 349 * Returns zero, or a negative error code. On success, this call clears 350 * the underlying hardware state reflecting endpoint halt and data toggle. 351 * Note that some hardware can't support this request (like pxa2xx_udc), 352 * and accordingly can't correctly implement interface altsettings. 353 */ 354static inline int usb_ep_clear_halt(struct usb_ep *ep) 355{ 356 return ep->ops->set_halt(ep, 0); 357} 358 359/** 360 * usb_ep_set_wedge - sets the halt feature and ignores clear requests 361 * @ep: the endpoint being wedged 362 * 363 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT) 364 * requests. If the gadget driver clears the halt status, it will 365 * automatically unwedge the endpoint. 366 * 367 * Returns zero on success, else negative errno. 368 */ 369static inline int 370usb_ep_set_wedge(struct usb_ep *ep) 371{ 372 if (ep->ops->set_wedge) 373 return ep->ops->set_wedge(ep); 374 else 375 return ep->ops->set_halt(ep, 1); 376} 377 378/** 379 * usb_ep_fifo_status - returns number of bytes in fifo, or error 380 * @ep: the endpoint whose fifo status is being checked. 381 * 382 * FIFO endpoints may have "unclaimed data" in them in certain cases, 383 * such as after aborted transfers. Hosts may not have collected all 384 * the IN data written by the gadget driver (and reported by a request 385 * completion). The gadget driver may not have collected all the data 386 * written OUT to it by the host. Drivers that need precise handling for 387 * fault reporting or recovery may need to use this call. 388 * 389 * This returns the number of such bytes in the fifo, or a negative 390 * errno if the endpoint doesn't use a FIFO or doesn't support such 391 * precise handling. 392 */ 393static inline int usb_ep_fifo_status(struct usb_ep *ep) 394{ 395 if (ep->ops->fifo_status) 396 return ep->ops->fifo_status(ep); 397 else 398 return -EOPNOTSUPP; 399} 400 401/** 402 * usb_ep_fifo_flush - flushes contents of a fifo 403 * @ep: the endpoint whose fifo is being flushed. 404 * 405 * This call may be used to flush the "unclaimed data" that may exist in 406 * an endpoint fifo after abnormal transaction terminations. The call 407 * must never be used except when endpoint is not being used for any 408 * protocol translation. 409 */ 410static inline void usb_ep_fifo_flush(struct usb_ep *ep) 411{ 412 if (ep->ops->fifo_flush) 413 ep->ops->fifo_flush(ep); 414} 415 416 417/*-------------------------------------------------------------------------*/ 418 419struct usb_gadget; 420 421/* the rest of the api to the controller hardware: device operations, 422 * which don't involve endpoints (or i/o). 423 */ 424struct usb_gadget_ops { 425 int (*get_frame)(struct usb_gadget *); 426 int (*wakeup)(struct usb_gadget *); 427 int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered); 428 int (*vbus_session) (struct usb_gadget *, int is_active); 429 int (*vbus_draw) (struct usb_gadget *, unsigned mA); 430 int (*pullup) (struct usb_gadget *, int is_on); 431 int (*ioctl)(struct usb_gadget *, 432 unsigned code, unsigned long param); 433}; 434 435/** 436 * struct usb_gadget - represents a usb slave device 437 * @ops: Function pointers used to access hardware-specific operations. 438 * @ep0: Endpoint zero, used when reading or writing responses to 439 * driver setup() requests 440 * @ep_list: List of other endpoints supported by the device. 441 * @speed: Speed of current connection to USB host. 442 * @is_dualspeed: True if the controller supports both high and full speed 443 * operation. If it does, the gadget driver must also support both. 444 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the 445 * gadget driver must provide a USB OTG descriptor. 446 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable 447 * is in the Mini-AB jack, and HNP has been used to switch roles 448 * so that the "A" device currently acts as A-Peripheral, not A-Host. 449 * @a_hnp_support: OTG device feature flag, indicating that the A-Host 450 * supports HNP at this port. 451 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host 452 * only supports HNP on a different root port. 453 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host 454 * enabled HNP support. 455 * @name: Identifies the controller hardware type. Used in diagnostics 456 * and sometimes configuration. 457 * @dev: Driver model state for this abstract device. 458 * 459 * Gadgets have a mostly-portable "gadget driver" implementing device 460 * functions, handling all usb configurations and interfaces. Gadget 461 * drivers talk to hardware-specific code indirectly, through ops vectors. 462 * That insulates the gadget driver from hardware details, and packages 463 * the hardware endpoints through generic i/o queues. The "usb_gadget" 464 * and "usb_ep" interfaces provide that insulation from the hardware. 465 * 466 * Except for the driver data, all fields in this structure are 467 * read-only to the gadget driver. That driver data is part of the 468 * "driver model" infrastructure in 2.6 (and later) kernels, and for 469 * earlier systems is grouped in a similar structure that's not known 470 * to the rest of the kernel. 471 * 472 * Values of the three OTG device feature flags are updated before the 473 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before 474 * driver suspend() calls. They are valid only when is_otg, and when the 475 * device is acting as a B-Peripheral (so is_a_peripheral is false). 476 */ 477struct usb_gadget { 478 /* readonly to gadget driver */ 479 const struct usb_gadget_ops *ops; 480 struct usb_ep *ep0; 481 struct list_head ep_list; /* of usb_ep */ 482 enum usb_device_speed speed; 483 unsigned is_dualspeed:1; 484 unsigned is_otg:1; 485 unsigned is_a_peripheral:1; 486 unsigned b_hnp_enable:1; 487 unsigned a_hnp_support:1; 488 unsigned a_alt_hnp_support:1; 489 const char *name; 490 struct device dev; 491}; 492 493static inline void set_gadget_data(struct usb_gadget *gadget, void *data) 494 { dev_set_drvdata(&gadget->dev, data); } 495static inline void *get_gadget_data(struct usb_gadget *gadget) 496 { return dev_get_drvdata(&gadget->dev); } 497static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev) 498{ 499 return container_of(dev, struct usb_gadget, dev); 500} 501 502/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */ 503#define gadget_for_each_ep(tmp, gadget) \ 504 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list) 505 506 507/** 508 * gadget_is_dualspeed - return true iff the hardware handles high speed 509 * @g: controller that might support both high and full speeds 510 */ 511static inline int gadget_is_dualspeed(struct usb_gadget *g) 512{ 513#ifdef CONFIG_USB_GADGET_DUALSPEED 514 /* runtime test would check "g->is_dualspeed" ... that might be 515 * useful to work around hardware bugs, but is mostly pointless 516 */ 517 return 1; 518#else 519 return 0; 520#endif 521} 522 523/** 524 * gadget_is_otg - return true iff the hardware is OTG-ready 525 * @g: controller that might have a Mini-AB connector 526 * 527 * This is a runtime test, since kernels with a USB-OTG stack sometimes 528 * run on boards which only have a Mini-B (or Mini-A) connector. 529 */ 530static inline int gadget_is_otg(struct usb_gadget *g) 531{ 532#ifdef CONFIG_USB_OTG 533 return g->is_otg; 534#else 535 return 0; 536#endif 537} 538 539/** 540 * usb_gadget_frame_number - returns the current frame number 541 * @gadget: controller that reports the frame number 542 * 543 * Returns the usb frame number, normally eleven bits from a SOF packet, 544 * or negative errno if this device doesn't support this capability. 545 */ 546static inline int usb_gadget_frame_number(struct usb_gadget *gadget) 547{ 548 return gadget->ops->get_frame(gadget); 549} 550 551/** 552 * usb_gadget_wakeup - tries to wake up the host connected to this gadget 553 * @gadget: controller used to wake up the host 554 * 555 * Returns zero on success, else negative error code if the hardware 556 * doesn't support such attempts, or its support has not been enabled 557 * by the usb host. Drivers must return device descriptors that report 558 * their ability to support this, or hosts won't enable it. 559 * 560 * This may also try to use SRP to wake the host and start enumeration, 561 * even if OTG isn't otherwise in use. OTG devices may also start 562 * remote wakeup even when hosts don't explicitly enable it. 563 */ 564static inline int usb_gadget_wakeup(struct usb_gadget *gadget) 565{ 566 if (!gadget->ops->wakeup) 567 return -EOPNOTSUPP; 568 return gadget->ops->wakeup(gadget); 569} 570 571/** 572 * usb_gadget_set_selfpowered - sets the device selfpowered feature. 573 * @gadget:the device being declared as self-powered 574 * 575 * this affects the device status reported by the hardware driver 576 * to reflect that it now has a local power supply. 577 * 578 * returns zero on success, else negative errno. 579 */ 580static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget) 581{ 582 if (!gadget->ops->set_selfpowered) 583 return -EOPNOTSUPP; 584 return gadget->ops->set_selfpowered(gadget, 1); 585} 586 587/** 588 * usb_gadget_clear_selfpowered - clear the device selfpowered feature. 589 * @gadget:the device being declared as bus-powered 590 * 591 * this affects the device status reported by the hardware driver. 592 * some hardware may not support bus-powered operation, in which 593 * case this feature's value can never change. 594 * 595 * returns zero on success, else negative errno. 596 */ 597static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget) 598{ 599 if (!gadget->ops->set_selfpowered) 600 return -EOPNOTSUPP; 601 return gadget->ops->set_selfpowered(gadget, 0); 602} 603 604/** 605 * usb_gadget_vbus_connect - Notify controller that VBUS is powered 606 * @gadget:The device which now has VBUS power. 607 * Context: can sleep 608 * 609 * This call is used by a driver for an external transceiver (or GPIO) 610 * that detects a VBUS power session starting. Common responses include 611 * resuming the controller, activating the D+ (or D-) pullup to let the 612 * host detect that a USB device is attached, and starting to draw power 613 * (8mA or possibly more, especially after SET_CONFIGURATION). 614 * 615 * Returns zero on success, else negative errno. 616 */ 617static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget) 618{ 619 if (!gadget->ops->vbus_session) 620 return -EOPNOTSUPP; 621 return gadget->ops->vbus_session(gadget, 1); 622} 623 624/** 625 * usb_gadget_vbus_draw - constrain controller's VBUS power usage 626 * @gadget:The device whose VBUS usage is being described 627 * @mA:How much current to draw, in milliAmperes. This should be twice 628 * the value listed in the configuration descriptor bMaxPower field. 629 * 630 * This call is used by gadget drivers during SET_CONFIGURATION calls, 631 * reporting how much power the device may consume. For example, this 632 * could affect how quickly batteries are recharged. 633 * 634 * Returns zero on success, else negative errno. 635 */ 636static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA) 637{ 638 if (!gadget->ops->vbus_draw) 639 return -EOPNOTSUPP; 640 return gadget->ops->vbus_draw(gadget, mA); 641} 642 643/** 644 * usb_gadget_vbus_disconnect - notify controller about VBUS session end 645 * @gadget:the device whose VBUS supply is being described 646 * Context: can sleep 647 * 648 * This call is used by a driver for an external transceiver (or GPIO) 649 * that detects a VBUS power session ending. Common responses include 650 * reversing everything done in usb_gadget_vbus_connect(). 651 * 652 * Returns zero on success, else negative errno. 653 */ 654static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) 655{ 656 if (!gadget->ops->vbus_session) 657 return -EOPNOTSUPP; 658 return gadget->ops->vbus_session(gadget, 0); 659} 660 661/** 662 * usb_gadget_connect - software-controlled connect to USB host 663 * @gadget:the peripheral being connected 664 * 665 * Enables the D+ (or potentially D-) pullup. The host will start 666 * enumerating this gadget when the pullup is active and a VBUS session 667 * is active (the link is powered). This pullup is always enabled unless 668 * usb_gadget_disconnect() has been used to disable it. 669 * 670 * Returns zero on success, else negative errno. 671 */ 672static inline int usb_gadget_connect(struct usb_gadget *gadget) 673{ 674 if (!gadget->ops->pullup) 675 return -EOPNOTSUPP; 676 return gadget->ops->pullup(gadget, 1); 677} 678 679/** 680 * usb_gadget_disconnect - software-controlled disconnect from USB host 681 * @gadget:the peripheral being disconnected 682 * 683 * Disables the D+ (or potentially D-) pullup, which the host may see 684 * as a disconnect (when a VBUS session is active). Not all systems 685 * support software pullup controls. 686 * 687 * This routine may be used during the gadget driver bind() call to prevent 688 * the peripheral from ever being visible to the USB host, unless later 689 * usb_gadget_connect() is called. For example, user mode components may 690 * need to be activated before the system can talk to hosts. 691 * 692 * Returns zero on success, else negative errno. 693 */ 694static inline int usb_gadget_disconnect(struct usb_gadget *gadget) 695{ 696 if (!gadget->ops->pullup) 697 return -EOPNOTSUPP; 698 return gadget->ops->pullup(gadget, 0); 699} 700 701 702/*-------------------------------------------------------------------------*/ 703 704/** 705 * struct usb_gadget_driver - driver for usb 'slave' devices 706 * @function: String describing the gadget's function 707 * @speed: Highest speed the driver handles. 708 * @setup: Invoked for ep0 control requests that aren't handled by 709 * the hardware level driver. Most calls must be handled by 710 * the gadget driver, including descriptor and configuration 711 * management. The 16 bit members of the setup data are in 712 * USB byte order. Called in_interrupt; this may not sleep. Driver 713 * queues a response to ep0, or returns negative to stall. 714 * @disconnect: Invoked after all transfers have been stopped, 715 * when the host is disconnected. May be called in_interrupt; this 716 * may not sleep. Some devices can't detect disconnect, so this might 717 * not be called except as part of controller shutdown. 718 * @unbind: Invoked when the driver is unbound from a gadget, 719 * usually from rmmod (after a disconnect is reported). 720 * Called in a context that permits sleeping. 721 * @suspend: Invoked on USB suspend. May be called in_interrupt. 722 * @resume: Invoked on USB resume. May be called in_interrupt. 723 * @driver: Driver model state for this driver. 724 * 725 * Devices are disabled till a gadget driver successfully bind()s, which 726 * means the driver will handle setup() requests needed to enumerate (and 727 * meet "chapter 9" requirements) then do some useful work. 728 * 729 * If gadget->is_otg is true, the gadget driver must provide an OTG 730 * descriptor during enumeration, or else fail the bind() call. In such 731 * cases, no USB traffic may flow until both bind() returns without 732 * having called usb_gadget_disconnect(), and the USB host stack has 733 * initialized. 734 * 735 * Drivers use hardware-specific knowledge to configure the usb hardware. 736 * endpoint addressing is only one of several hardware characteristics that 737 * are in descriptors the ep0 implementation returns from setup() calls. 738 * 739 * Except for ep0 implementation, most driver code shouldn't need change to 740 * run on top of different usb controllers. It'll use endpoints set up by 741 * that ep0 implementation. 742 * 743 * The usb controller driver handles a few standard usb requests. Those 744 * include set_address, and feature flags for devices, interfaces, and 745 * endpoints (the get_status, set_feature, and clear_feature requests). 746 * 747 * Accordingly, the driver's setup() callback must always implement all 748 * get_descriptor requests, returning at least a device descriptor and 749 * a configuration descriptor. Drivers must make sure the endpoint 750 * descriptors match any hardware constraints. Some hardware also constrains 751 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3). 752 * 753 * The driver's setup() callback must also implement set_configuration, 754 * and should also implement set_interface, get_configuration, and 755 * get_interface. Setting a configuration (or interface) is where 756 * endpoints should be activated or (config 0) shut down. 757 * 758 * (Note that only the default control endpoint is supported. Neither 759 * hosts nor devices generally support control traffic except to ep0.) 760 * 761 * Most devices will ignore USB suspend/resume operations, and so will 762 * not provide those callbacks. However, some may need to change modes 763 * when the host is not longer directing those activities. For example, 764 * local controls (buttons, dials, etc) may need to be re-enabled since 765 * the (remote) host can't do that any longer; or an error state might 766 * be cleared, to make the device behave identically whether or not 767 * power is maintained. 768 */ 769struct usb_gadget_driver { 770 char *function; 771 enum usb_device_speed speed; 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_probe_driver - probe a gadget driver 796 * @driver: the driver being registered 797 * @bind: the driver's bind callback 798 * Context: can sleep 799 * 800 * Call this in your gadget driver's module initialization function, 801 * to tell the underlying usb controller driver about your driver. 802 * The @bind() function will be called to bind it to a gadget before this 803 * registration call returns. It's expected that the @bind() function will 804 * be in init sections. 805 */ 806int usb_gadget_probe_driver(struct usb_gadget_driver *driver, 807 int (*bind)(struct usb_gadget *)); 808 809/** 810 * usb_gadget_unregister_driver - unregister a gadget driver 811 * @driver:the driver being unregistered 812 * Context: can sleep 813 * 814 * Call this in your gadget driver's module cleanup function, 815 * to tell the underlying usb controller that your driver is 816 * going away. If the controller is connected to a USB host, 817 * it will first disconnect(). The driver is also requested 818 * to unbind() and clean up any device state, before this procedure 819 * finally returns. It's expected that the unbind() functions 820 * will in in exit sections, so may not be linked in some kernels. 821 */ 822int usb_gadget_unregister_driver(struct usb_gadget_driver *driver); 823 824/*-------------------------------------------------------------------------*/ 825 826/* utility to simplify dealing with string descriptors */ 827 828/** 829 * struct usb_string - wraps a C string and its USB id 830 * @id:the (nonzero) ID for this string 831 * @s:the string, in UTF-8 encoding 832 * 833 * If you're using usb_gadget_get_string(), use this to wrap a string 834 * together with its ID. 835 */ 836struct usb_string { 837 u8 id; 838 const char *s; 839}; 840 841/** 842 * struct usb_gadget_strings - a set of USB strings in a given language 843 * @language:identifies the strings' language (0x0409 for en-us) 844 * @strings:array of strings with their ids 845 * 846 * If you're using usb_gadget_get_string(), use this to wrap all the 847 * strings for a given language. 848 */ 849struct usb_gadget_strings { 850 u16 language; /* 0x0409 for en-us */ 851 struct usb_string *strings; 852}; 853 854/* put descriptor for string with that id into buf (buflen >= 256) */ 855int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf); 856 857/*-------------------------------------------------------------------------*/ 858 859/* utility to simplify managing config descriptors */ 860 861/* write vector of descriptors into buffer */ 862int usb_descriptor_fillbuf(void *, unsigned, 863 const struct usb_descriptor_header **); 864 865/* build config descriptor from single descriptor vector */ 866int usb_gadget_config_buf(const struct usb_config_descriptor *config, 867 void *buf, unsigned buflen, const struct usb_descriptor_header **desc); 868 869/* copy a NULL-terminated vector of descriptors */ 870struct usb_descriptor_header **usb_copy_descriptors( 871 struct usb_descriptor_header **); 872 873/* return copy of endpoint descriptor given original descriptor set */ 874struct usb_endpoint_descriptor *usb_find_endpoint( 875 struct usb_descriptor_header **src, 876 struct usb_descriptor_header **copy, 877 struct usb_endpoint_descriptor *match); 878 879/** 880 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors() 881 * @v: vector of descriptors 882 */ 883static inline void usb_free_descriptors(struct usb_descriptor_header **v) 884{ 885 kfree(v); 886} 887 888/*-------------------------------------------------------------------------*/ 889 890/* utility wrapping a simple endpoint selection policy */ 891 892extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *, 893 struct usb_endpoint_descriptor *) __devinit; 894 895extern void usb_ep_autoconfig_reset(struct usb_gadget *) __devinit; 896 897#endif /* __LINUX_USB_GADGET_H */ 898