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/device.h> 19#include <linux/errno.h> 20#include <linux/init.h> 21#include <linux/list.h> 22#include <linux/slab.h> 23#include <linux/types.h> 24#include <linux/usb/ch9.h> 25 26struct usb_ep; 27 28/** 29 * struct usb_request - describes one i/o request 30 * @buf: Buffer used for data. Always provide this; some controllers 31 * only use PIO, or don't use DMA for some endpoints. 32 * @dma: DMA address corresponding to 'buf'. If you don't set this 33 * field, and the usb controller needs one, it is responsible 34 * for mapping and unmapping the buffer. 35 * @length: Length of that data 36 * @stream_id: The stream id, when USB3.0 bulk streams are being used 37 * @no_interrupt: If true, hints that no completion irq is needed. 38 * Helpful sometimes with deep request queues that are handled 39 * directly by DMA controllers. 40 * @zero: If true, when writing data, makes the last packet be "short" 41 * by adding a zero length packet as needed; 42 * @short_not_ok: When reading data, makes short packets be 43 * treated as errors (queue stops advancing till cleanup). 44 * @complete: Function called when request completes, so this request and 45 * its buffer may be re-used. The function will always be called with 46 * interrupts disabled, and it must not sleep. 47 * Reads terminate with a short packet, or when the buffer fills, 48 * whichever comes first. When writes terminate, some data bytes 49 * will usually still be in flight (often in a hardware fifo). 50 * Errors (for reads or writes) stop the queue from advancing 51 * until the completion function returns, so that any transfers 52 * invalidated by the error may first be dequeued. 53 * @context: For use by the completion callback 54 * @list: For use by the gadget driver. 55 * @status: Reports completion code, zero or a negative errno. 56 * Normally, faults block the transfer queue from advancing until 57 * the completion callback returns. 58 * Code "-ESHUTDOWN" indicates completion caused by device disconnect, 59 * or when the driver disabled the endpoint. 60 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT 61 * transfers) this may be less than the requested length. If the 62 * short_not_ok flag is set, short reads are treated as errors 63 * even when status otherwise indicates successful completion. 64 * Note that for writes (IN transfers) some data bytes may still 65 * reside in a device-side FIFO when the request is reported as 66 * complete. 67 * 68 * These are allocated/freed through the endpoint they're used with. The 69 * hardware's driver can add extra per-request data to the memory it returns, 70 * which often avoids separate memory allocations (potential failures), 71 * later when the request is queued. 72 * 73 * Request flags affect request handling, such as whether a zero length 74 * packet is written (the "zero" flag), whether a short read should be 75 * treated as an error (blocking request queue advance, the "short_not_ok" 76 * flag), or hinting that an interrupt is not required (the "no_interrupt" 77 * flag, for use with deep request queues). 78 * 79 * Bulk endpoints can use any size buffers, and can also be used for interrupt 80 * transfers. interrupt-only endpoints can be much less functional. 81 * 82 * NOTE: this is analogous to 'struct urb' on the host side, except that 83 * it's thinner and promotes more pre-allocation. 84 */ 85 86struct usb_request { 87 void *buf; 88 unsigned length; 89 dma_addr_t dma; 90 91 unsigned stream_id:16; 92 unsigned no_interrupt:1; 93 unsigned zero:1; 94 unsigned short_not_ok:1; 95 96 void (*complete)(struct usb_ep *ep, 97 struct usb_request *req); 98 void *context; 99 struct list_head list; 100 101 int status; 102 unsigned actual; 103}; 104 105/*-------------------------------------------------------------------------*/ 106 107/* endpoint-specific parts of the api to the usb controller hardware. 108 * unlike the urb model, (de)multiplexing layers are not required. 109 * (so this api could slash overhead if used on the host side...) 110 * 111 * note that device side usb controllers commonly differ in how many 112 * endpoints they support, as well as their capabilities. 113 */ 114struct usb_ep_ops { 115 int (*enable) (struct usb_ep *ep, 116 const struct usb_endpoint_descriptor *desc); 117 int (*disable) (struct usb_ep *ep); 118 119 struct usb_request *(*alloc_request) (struct usb_ep *ep, 120 gfp_t gfp_flags); 121 void (*free_request) (struct usb_ep *ep, struct usb_request *req); 122 123 int (*queue) (struct usb_ep *ep, struct usb_request *req, 124 gfp_t gfp_flags); 125 int (*dequeue) (struct usb_ep *ep, struct usb_request *req); 126 127 int (*set_halt) (struct usb_ep *ep, int value); 128 int (*set_wedge) (struct usb_ep *ep); 129 130 int (*fifo_status) (struct usb_ep *ep); 131 void (*fifo_flush) (struct usb_ep *ep); 132}; 133 134/** 135 * struct usb_ep - device side representation of USB endpoint 136 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk" 137 * @ops: Function pointers used to access hardware-specific operations. 138 * @ep_list:the gadget's ep_list holds all of its endpoints 139 * @maxpacket:The maximum packet size used on this endpoint. The initial 140 * value can sometimes be reduced (hardware allowing), according to 141 * the endpoint descriptor used to configure the endpoint. 142 * @max_streams: The maximum number of streams supported 143 * by this EP (0 - 16, actual number is 2^n) 144 * @mult: multiplier, 'mult' value for SS Isoc EPs 145 * @maxburst: the maximum number of bursts supported by this EP (for usb3) 146 * @driver_data:for use by the gadget driver. 147 * @address: used to identify the endpoint when finding descriptor that 148 * matches connection speed 149 * @desc: endpoint descriptor. This pointer is set before the endpoint is 150 * enabled and remains valid until the endpoint is disabled. 151 * @comp_desc: In case of SuperSpeed support, this is the endpoint companion 152 * descriptor that is used to configure the endpoint 153 * 154 * the bus controller driver lists all the general purpose endpoints in 155 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list, 156 * and is accessed only in response to a driver setup() callback. 157 */ 158struct usb_ep { 159 void *driver_data; 160 161 const char *name; 162 const struct usb_ep_ops *ops; 163 struct list_head ep_list; 164 unsigned maxpacket:16; 165 unsigned max_streams:16; 166 unsigned mult:2; 167 unsigned maxburst:4; 168 u8 address; 169 const struct usb_endpoint_descriptor *desc; 170 const struct usb_ss_ep_comp_descriptor *comp_desc; 171}; 172 173/*-------------------------------------------------------------------------*/ 174 175/** 176 * usb_ep_enable - configure endpoint, making it usable 177 * @ep:the endpoint being configured. may not be the endpoint named "ep0". 178 * drivers discover endpoints through the ep_list of a usb_gadget. 179 * 180 * When configurations are set, or when interface settings change, the driver 181 * will enable or disable the relevant endpoints. while it is enabled, an 182 * endpoint may be used for i/o until the driver receives a disconnect() from 183 * the host or until the endpoint is disabled. 184 * 185 * the ep0 implementation (which calls this routine) must ensure that the 186 * hardware capabilities of each endpoint match the descriptor provided 187 * for it. for example, an endpoint named "ep2in-bulk" would be usable 188 * for interrupt transfers as well as bulk, but it likely couldn't be used 189 * for iso transfers or for endpoint 14. some endpoints are fully 190 * configurable, with more generic names like "ep-a". (remember that for 191 * USB, "in" means "towards the USB master".) 192 * 193 * returns zero, or a negative error code. 194 */ 195static inline int usb_ep_enable(struct usb_ep *ep) 196{ 197 return ep->ops->enable(ep, ep->desc); 198} 199 200/** 201 * usb_ep_disable - endpoint is no longer usable 202 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0". 203 * 204 * no other task may be using this endpoint when this is called. 205 * any pending and uncompleted requests will complete with status 206 * indicating disconnect (-ESHUTDOWN) before this call returns. 207 * gadget drivers must call usb_ep_enable() again before queueing 208 * requests to the endpoint. 209 * 210 * returns zero, or a negative error code. 211 */ 212static inline int usb_ep_disable(struct usb_ep *ep) 213{ 214 return ep->ops->disable(ep); 215} 216 217/** 218 * usb_ep_alloc_request - allocate a request object to use with this endpoint 219 * @ep:the endpoint to be used with with the request 220 * @gfp_flags:GFP_* flags to use 221 * 222 * Request objects must be allocated with this call, since they normally 223 * need controller-specific setup and may even need endpoint-specific 224 * resources such as allocation of DMA descriptors. 225 * Requests may be submitted with usb_ep_queue(), and receive a single 226 * completion callback. Free requests with usb_ep_free_request(), when 227 * they are no longer needed. 228 * 229 * Returns the request, or null if one could not be allocated. 230 */ 231static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, 232 gfp_t gfp_flags) 233{ 234 return ep->ops->alloc_request(ep, gfp_flags); 235} 236 237/** 238 * usb_ep_free_request - frees a request object 239 * @ep:the endpoint associated with the request 240 * @req:the request being freed 241 * 242 * Reverses the effect of usb_ep_alloc_request(). 243 * Caller guarantees the request is not queued, and that it will 244 * no longer be requeued (or otherwise used). 245 */ 246static inline void usb_ep_free_request(struct usb_ep *ep, 247 struct usb_request *req) 248{ 249 ep->ops->free_request(ep, req); 250} 251 252/** 253 * usb_ep_queue - queues (submits) an I/O request to an endpoint. 254 * @ep:the endpoint associated with the request 255 * @req:the request being submitted 256 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't 257 * pre-allocate all necessary memory with the request. 258 * 259 * This tells the device controller to perform the specified request through 260 * that endpoint (reading or writing a buffer). When the request completes, 261 * including being canceled by usb_ep_dequeue(), the request's completion 262 * routine is called to return the request to the driver. Any endpoint 263 * (except control endpoints like ep0) may have more than one transfer 264 * request queued; they complete in FIFO order. Once a gadget driver 265 * submits a request, that request may not be examined or modified until it 266 * is given back to that driver through the completion callback. 267 * 268 * Each request is turned into one or more packets. The controller driver 269 * never merges adjacent requests into the same packet. OUT transfers 270 * will sometimes use data that's already buffered in the hardware. 271 * Drivers can rely on the fact that the first byte of the request's buffer 272 * always corresponds to the first byte of some USB packet, for both 273 * IN and OUT transfers. 274 * 275 * Bulk endpoints can queue any amount of data; the transfer is packetized 276 * automatically. The last packet will be short if the request doesn't fill it 277 * out completely. Zero length packets (ZLPs) should be avoided in portable 278 * protocols since not all usb hardware can successfully handle zero length 279 * packets. (ZLPs may be explicitly written, and may be implicitly written if 280 * the request 'zero' flag is set.) Bulk endpoints may also be used 281 * for interrupt transfers; but the reverse is not true, and some endpoints 282 * won't support every interrupt transfer. (Such as 768 byte packets.) 283 * 284 * Interrupt-only endpoints are less functional than bulk endpoints, for 285 * example by not supporting queueing or not handling buffers that are 286 * larger than the endpoint's maxpacket size. They may also treat data 287 * toggle differently. 288 * 289 * Control endpoints ... after getting a setup() callback, the driver queues 290 * one response (even if it would be zero length). That enables the 291 * status ack, after transferring data as specified in the response. Setup 292 * functions may return negative error codes to generate protocol stalls. 293 * (Note that some USB device controllers disallow protocol stall responses 294 * in some cases.) When control responses are deferred (the response is 295 * written after the setup callback returns), then usb_ep_set_halt() may be 296 * used on ep0 to trigger protocol stalls. Depending on the controller, 297 * it may not be possible to trigger a status-stage protocol stall when the 298 * data stage is over, that is, from within the response's completion 299 * routine. 300 * 301 * For periodic endpoints, like interrupt or isochronous ones, the usb host 302 * arranges to poll once per interval, and the gadget driver usually will 303 * have queued some data to transfer at that time. 304 * 305 * Returns zero, or a negative error code. Endpoints that are not enabled 306 * report errors; errors will also be 307 * reported when the usb peripheral is disconnected. 308 */ 309static inline int usb_ep_queue(struct usb_ep *ep, 310 struct usb_request *req, gfp_t gfp_flags) 311{ 312 return ep->ops->queue(ep, req, gfp_flags); 313} 314 315/** 316 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint 317 * @ep:the endpoint associated with the request 318 * @req:the request being canceled 319 * 320 * if the request is still active on the endpoint, it is dequeued and its 321 * completion routine is called (with status -ECONNRESET); else a negative 322 * error code is returned. 323 * 324 * note that some hardware can't clear out write fifos (to unlink the request 325 * at the head of the queue) except as part of disconnecting from usb. such 326 * restrictions prevent drivers from supporting configuration changes, 327 * even to configuration zero (a "chapter 9" requirement). 328 */ 329static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req) 330{ 331 return ep->ops->dequeue(ep, req); 332} 333 334/** 335 * usb_ep_set_halt - sets the endpoint halt feature. 336 * @ep: the non-isochronous endpoint being stalled 337 * 338 * Use this to stall an endpoint, perhaps as an error report. 339 * Except for control endpoints, 340 * the endpoint stays halted (will not stream any data) until the host 341 * clears this feature; drivers may need to empty the endpoint's request 342 * queue first, to make sure no inappropriate transfers happen. 343 * 344 * Note that while an endpoint CLEAR_FEATURE will be invisible to the 345 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the 346 * current altsetting, see usb_ep_clear_halt(). When switching altsettings, 347 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints. 348 * 349 * Returns zero, or a negative error code. On success, this call sets 350 * underlying hardware state that blocks data transfers. 351 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any 352 * transfer requests are still queued, or if the controller hardware 353 * (usually a FIFO) still holds bytes that the host hasn't collected. 354 */ 355static inline int usb_ep_set_halt(struct usb_ep *ep) 356{ 357 return ep->ops->set_halt(ep, 1); 358} 359 360/** 361 * usb_ep_clear_halt - clears endpoint halt, and resets toggle 362 * @ep:the bulk or interrupt endpoint being reset 363 * 364 * Use this when responding to the standard usb "set interface" request, 365 * for endpoints that aren't reconfigured, after clearing any other state 366 * in the endpoint's i/o queue. 367 * 368 * Returns zero, or a negative error code. On success, this call clears 369 * the underlying hardware state reflecting endpoint halt and data toggle. 370 * Note that some hardware can't support this request (like pxa2xx_udc), 371 * and accordingly can't correctly implement interface altsettings. 372 */ 373static inline int usb_ep_clear_halt(struct usb_ep *ep) 374{ 375 return ep->ops->set_halt(ep, 0); 376} 377 378/** 379 * usb_ep_set_wedge - sets the halt feature and ignores clear requests 380 * @ep: the endpoint being wedged 381 * 382 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT) 383 * requests. If the gadget driver clears the halt status, it will 384 * automatically unwedge the endpoint. 385 * 386 * Returns zero on success, else negative errno. 387 */ 388static inline int 389usb_ep_set_wedge(struct usb_ep *ep) 390{ 391 if (ep->ops->set_wedge) 392 return ep->ops->set_wedge(ep); 393 else 394 return ep->ops->set_halt(ep, 1); 395} 396 397/** 398 * usb_ep_fifo_status - returns number of bytes in fifo, or error 399 * @ep: the endpoint whose fifo status is being checked. 400 * 401 * FIFO endpoints may have "unclaimed data" in them in certain cases, 402 * such as after aborted transfers. Hosts may not have collected all 403 * the IN data written by the gadget driver (and reported by a request 404 * completion). The gadget driver may not have collected all the data 405 * written OUT to it by the host. Drivers that need precise handling for 406 * fault reporting or recovery may need to use this call. 407 * 408 * This returns the number of such bytes in the fifo, or a negative 409 * errno if the endpoint doesn't use a FIFO or doesn't support such 410 * precise handling. 411 */ 412static inline int usb_ep_fifo_status(struct usb_ep *ep) 413{ 414 if (ep->ops->fifo_status) 415 return ep->ops->fifo_status(ep); 416 else 417 return -EOPNOTSUPP; 418} 419 420/** 421 * usb_ep_fifo_flush - flushes contents of a fifo 422 * @ep: the endpoint whose fifo is being flushed. 423 * 424 * This call may be used to flush the "unclaimed data" that may exist in 425 * an endpoint fifo after abnormal transaction terminations. The call 426 * must never be used except when endpoint is not being used for any 427 * protocol translation. 428 */ 429static inline void usb_ep_fifo_flush(struct usb_ep *ep) 430{ 431 if (ep->ops->fifo_flush) 432 ep->ops->fifo_flush(ep); 433} 434 435 436/*-------------------------------------------------------------------------*/ 437 438struct usb_dcd_config_params { 439 __u8 bU1devExitLat; /* U1 Device exit Latency */ 440#define USB_DEFAULT_U1_DEV_EXIT_LAT 0x01 /* Less then 1 microsec */ 441 __le16 bU2DevExitLat; /* U2 Device exit Latency */ 442#define USB_DEFAULT_U2_DEV_EXIT_LAT 0x1F4 /* Less then 500 microsec */ 443}; 444 445 446struct usb_gadget; 447struct usb_gadget_driver; 448 449/* the rest of the api to the controller hardware: device operations, 450 * which don't involve endpoints (or i/o). 451 */ 452struct usb_gadget_ops { 453 int (*get_frame)(struct usb_gadget *); 454 int (*wakeup)(struct usb_gadget *); 455 int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered); 456 int (*vbus_session) (struct usb_gadget *, int is_active); 457 int (*vbus_draw) (struct usb_gadget *, unsigned mA); 458 int (*pullup) (struct usb_gadget *, int is_on); 459 int (*ioctl)(struct usb_gadget *, 460 unsigned code, unsigned long param); 461 void (*get_config_params)(struct usb_dcd_config_params *); 462 int (*udc_start)(struct usb_gadget *, 463 struct usb_gadget_driver *); 464 int (*udc_stop)(struct usb_gadget *, 465 struct usb_gadget_driver *); 466 467 /* Those two are deprecated */ 468 int (*start)(struct usb_gadget_driver *, 469 int (*bind)(struct usb_gadget *)); 470 int (*stop)(struct usb_gadget_driver *); 471}; 472 473/** 474 * struct usb_gadget - represents a usb slave device 475 * @ops: Function pointers used to access hardware-specific operations. 476 * @ep0: Endpoint zero, used when reading or writing responses to 477 * driver setup() requests 478 * @ep_list: List of other endpoints supported by the device. 479 * @speed: Speed of current connection to USB host. 480 * @is_dualspeed: True if the controller supports both high and full speed 481 * operation. If it does, the gadget driver must also support both. 482 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the 483 * gadget driver must provide a USB OTG descriptor. 484 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable 485 * is in the Mini-AB jack, and HNP has been used to switch roles 486 * so that the "A" device currently acts as A-Peripheral, not A-Host. 487 * @a_hnp_support: OTG device feature flag, indicating that the A-Host 488 * supports HNP at this port. 489 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host 490 * only supports HNP on a different root port. 491 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host 492 * enabled HNP support. 493 * @name: Identifies the controller hardware type. Used in diagnostics 494 * and sometimes configuration. 495 * @dev: Driver model state for this abstract device. 496 * 497 * Gadgets have a mostly-portable "gadget driver" implementing device 498 * functions, handling all usb configurations and interfaces. Gadget 499 * drivers talk to hardware-specific code indirectly, through ops vectors. 500 * That insulates the gadget driver from hardware details, and packages 501 * the hardware endpoints through generic i/o queues. The "usb_gadget" 502 * and "usb_ep" interfaces provide that insulation from the hardware. 503 * 504 * Except for the driver data, all fields in this structure are 505 * read-only to the gadget driver. That driver data is part of the 506 * "driver model" infrastructure in 2.6 (and later) kernels, and for 507 * earlier systems is grouped in a similar structure that's not known 508 * to the rest of the kernel. 509 * 510 * Values of the three OTG device feature flags are updated before the 511 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before 512 * driver suspend() calls. They are valid only when is_otg, and when the 513 * device is acting as a B-Peripheral (so is_a_peripheral is false). 514 */ 515struct usb_gadget { 516 /* readonly to gadget driver */ 517 const struct usb_gadget_ops *ops; 518 struct usb_ep *ep0; 519 struct list_head ep_list; /* of usb_ep */ 520 enum usb_device_speed speed; 521 unsigned is_dualspeed:1; 522 unsigned is_otg:1; 523 unsigned is_a_peripheral:1; 524 unsigned b_hnp_enable:1; 525 unsigned a_hnp_support:1; 526 unsigned a_alt_hnp_support:1; 527 const char *name; 528 struct device dev; 529}; 530 531static inline void set_gadget_data(struct usb_gadget *gadget, void *data) 532 { dev_set_drvdata(&gadget->dev, data); } 533static inline void *get_gadget_data(struct usb_gadget *gadget) 534 { return dev_get_drvdata(&gadget->dev); } 535static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev) 536{ 537 return container_of(dev, struct usb_gadget, dev); 538} 539 540/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */ 541#define gadget_for_each_ep(tmp, gadget) \ 542 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list) 543 544 545/** 546 * gadget_is_dualspeed - return true iff the hardware handles high speed 547 * @g: controller that might support both high and full speeds 548 */ 549static inline int gadget_is_dualspeed(struct usb_gadget *g) 550{ 551#ifdef CONFIG_USB_GADGET_DUALSPEED 552 /* runtime test would check "g->is_dualspeed" ... that might be 553 * useful to work around hardware bugs, but is mostly pointless 554 */ 555 return 1; 556#else 557 return 0; 558#endif 559} 560 561/** 562 * gadget_is_superspeed() - return true if the hardware handles 563 * supperspeed 564 * @g: controller that might support supper speed 565 */ 566static inline int gadget_is_superspeed(struct usb_gadget *g) 567{ 568#ifdef CONFIG_USB_GADGET_SUPERSPEED 569 /* 570 * runtime test would check "g->is_superspeed" ... that might be 571 * useful to work around hardware bugs, but is mostly pointless 572 */ 573 return 1; 574#else 575 return 0; 576#endif 577} 578 579/** 580 * gadget_is_otg - return true iff the hardware is OTG-ready 581 * @g: controller that might have a Mini-AB connector 582 * 583 * This is a runtime test, since kernels with a USB-OTG stack sometimes 584 * run on boards which only have a Mini-B (or Mini-A) connector. 585 */ 586static inline int gadget_is_otg(struct usb_gadget *g) 587{ 588#ifdef CONFIG_USB_OTG 589 return g->is_otg; 590#else 591 return 0; 592#endif 593} 594 595/** 596 * usb_gadget_frame_number - returns the current frame number 597 * @gadget: controller that reports the frame number 598 * 599 * Returns the usb frame number, normally eleven bits from a SOF packet, 600 * or negative errno if this device doesn't support this capability. 601 */ 602static inline int usb_gadget_frame_number(struct usb_gadget *gadget) 603{ 604 return gadget->ops->get_frame(gadget); 605} 606 607/** 608 * usb_gadget_wakeup - tries to wake up the host connected to this gadget 609 * @gadget: controller used to wake up the host 610 * 611 * Returns zero on success, else negative error code if the hardware 612 * doesn't support such attempts, or its support has not been enabled 613 * by the usb host. Drivers must return device descriptors that report 614 * their ability to support this, or hosts won't enable it. 615 * 616 * This may also try to use SRP to wake the host and start enumeration, 617 * even if OTG isn't otherwise in use. OTG devices may also start 618 * remote wakeup even when hosts don't explicitly enable it. 619 */ 620static inline int usb_gadget_wakeup(struct usb_gadget *gadget) 621{ 622 if (!gadget->ops->wakeup) 623 return -EOPNOTSUPP; 624 return gadget->ops->wakeup(gadget); 625} 626 627/** 628 * usb_gadget_set_selfpowered - sets the device selfpowered feature. 629 * @gadget:the device being declared as self-powered 630 * 631 * this affects the device status reported by the hardware driver 632 * to reflect that it now has a local power supply. 633 * 634 * returns zero on success, else negative errno. 635 */ 636static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget) 637{ 638 if (!gadget->ops->set_selfpowered) 639 return -EOPNOTSUPP; 640 return gadget->ops->set_selfpowered(gadget, 1); 641} 642 643/** 644 * usb_gadget_clear_selfpowered - clear the device selfpowered feature. 645 * @gadget:the device being declared as bus-powered 646 * 647 * this affects the device status reported by the hardware driver. 648 * some hardware may not support bus-powered operation, in which 649 * case this feature's value can never change. 650 * 651 * returns zero on success, else negative errno. 652 */ 653static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget) 654{ 655 if (!gadget->ops->set_selfpowered) 656 return -EOPNOTSUPP; 657 return gadget->ops->set_selfpowered(gadget, 0); 658} 659 660/** 661 * usb_gadget_vbus_connect - Notify controller that VBUS is powered 662 * @gadget:The device which now has VBUS power. 663 * Context: can sleep 664 * 665 * This call is used by a driver for an external transceiver (or GPIO) 666 * that detects a VBUS power session starting. Common responses include 667 * resuming the controller, activating the D+ (or D-) pullup to let the 668 * host detect that a USB device is attached, and starting to draw power 669 * (8mA or possibly more, especially after SET_CONFIGURATION). 670 * 671 * Returns zero on success, else negative errno. 672 */ 673static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget) 674{ 675 if (!gadget->ops->vbus_session) 676 return -EOPNOTSUPP; 677 return gadget->ops->vbus_session(gadget, 1); 678} 679 680/** 681 * usb_gadget_vbus_draw - constrain controller's VBUS power usage 682 * @gadget:The device whose VBUS usage is being described 683 * @mA:How much current to draw, in milliAmperes. This should be twice 684 * the value listed in the configuration descriptor bMaxPower field. 685 * 686 * This call is used by gadget drivers during SET_CONFIGURATION calls, 687 * reporting how much power the device may consume. For example, this 688 * could affect how quickly batteries are recharged. 689 * 690 * Returns zero on success, else negative errno. 691 */ 692static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA) 693{ 694 if (!gadget->ops->vbus_draw) 695 return -EOPNOTSUPP; 696 return gadget->ops->vbus_draw(gadget, mA); 697} 698 699/** 700 * usb_gadget_vbus_disconnect - notify controller about VBUS session end 701 * @gadget:the device whose VBUS supply is being described 702 * Context: can sleep 703 * 704 * This call is used by a driver for an external transceiver (or GPIO) 705 * that detects a VBUS power session ending. Common responses include 706 * reversing everything done in usb_gadget_vbus_connect(). 707 * 708 * Returns zero on success, else negative errno. 709 */ 710static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) 711{ 712 if (!gadget->ops->vbus_session) 713 return -EOPNOTSUPP; 714 return gadget->ops->vbus_session(gadget, 0); 715} 716 717/** 718 * usb_gadget_connect - software-controlled connect to USB host 719 * @gadget:the peripheral being connected 720 * 721 * Enables the D+ (or potentially D-) pullup. The host will start 722 * enumerating this gadget when the pullup is active and a VBUS session 723 * is active (the link is powered). This pullup is always enabled unless 724 * usb_gadget_disconnect() has been used to disable it. 725 * 726 * Returns zero on success, else negative errno. 727 */ 728static inline int usb_gadget_connect(struct usb_gadget *gadget) 729{ 730 if (!gadget->ops->pullup) 731 return -EOPNOTSUPP; 732 return gadget->ops->pullup(gadget, 1); 733} 734 735/** 736 * usb_gadget_disconnect - software-controlled disconnect from USB host 737 * @gadget:the peripheral being disconnected 738 * 739 * Disables the D+ (or potentially D-) pullup, which the host may see 740 * as a disconnect (when a VBUS session is active). Not all systems 741 * support software pullup controls. 742 * 743 * This routine may be used during the gadget driver bind() call to prevent 744 * the peripheral from ever being visible to the USB host, unless later 745 * usb_gadget_connect() is called. For example, user mode components may 746 * need to be activated before the system can talk to hosts. 747 * 748 * Returns zero on success, else negative errno. 749 */ 750static inline int usb_gadget_disconnect(struct usb_gadget *gadget) 751{ 752 if (!gadget->ops->pullup) 753 return -EOPNOTSUPP; 754 return gadget->ops->pullup(gadget, 0); 755} 756 757 758/*-------------------------------------------------------------------------*/ 759 760/** 761 * struct usb_gadget_driver - driver for usb 'slave' devices 762 * @function: String describing the gadget's function 763 * @speed: Highest speed the driver handles. 764 * @setup: Invoked for ep0 control requests that aren't handled by 765 * the hardware level driver. Most calls must be handled by 766 * the gadget driver, including descriptor and configuration 767 * management. The 16 bit members of the setup data are in 768 * USB byte order. Called in_interrupt; this may not sleep. Driver 769 * queues a response to ep0, or returns negative to stall. 770 * @disconnect: Invoked after all transfers have been stopped, 771 * when the host is disconnected. May be called in_interrupt; this 772 * may not sleep. Some devices can't detect disconnect, so this might 773 * not be called except as part of controller shutdown. 774 * @unbind: Invoked when the driver is unbound from a gadget, 775 * usually from rmmod (after a disconnect is reported). 776 * Called in a context that permits sleeping. 777 * @suspend: Invoked on USB suspend. May be called in_interrupt. 778 * @resume: Invoked on USB resume. May be called in_interrupt. 779 * @driver: Driver model state for this driver. 780 * 781 * Devices are disabled till a gadget driver successfully bind()s, which 782 * means the driver will handle setup() requests needed to enumerate (and 783 * meet "chapter 9" requirements) then do some useful work. 784 * 785 * If gadget->is_otg is true, the gadget driver must provide an OTG 786 * descriptor during enumeration, or else fail the bind() call. In such 787 * cases, no USB traffic may flow until both bind() returns without 788 * having called usb_gadget_disconnect(), and the USB host stack has 789 * initialized. 790 * 791 * Drivers use hardware-specific knowledge to configure the usb hardware. 792 * endpoint addressing is only one of several hardware characteristics that 793 * are in descriptors the ep0 implementation returns from setup() calls. 794 * 795 * Except for ep0 implementation, most driver code shouldn't need change to 796 * run on top of different usb controllers. It'll use endpoints set up by 797 * that ep0 implementation. 798 * 799 * The usb controller driver handles a few standard usb requests. Those 800 * include set_address, and feature flags for devices, interfaces, and 801 * endpoints (the get_status, set_feature, and clear_feature requests). 802 * 803 * Accordingly, the driver's setup() callback must always implement all 804 * get_descriptor requests, returning at least a device descriptor and 805 * a configuration descriptor. Drivers must make sure the endpoint 806 * descriptors match any hardware constraints. Some hardware also constrains 807 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3). 808 * 809 * The driver's setup() callback must also implement set_configuration, 810 * and should also implement set_interface, get_configuration, and 811 * get_interface. Setting a configuration (or interface) is where 812 * endpoints should be activated or (config 0) shut down. 813 * 814 * (Note that only the default control endpoint is supported. Neither 815 * hosts nor devices generally support control traffic except to ep0.) 816 * 817 * Most devices will ignore USB suspend/resume operations, and so will 818 * not provide those callbacks. However, some may need to change modes 819 * when the host is not longer directing those activities. For example, 820 * local controls (buttons, dials, etc) may need to be re-enabled since 821 * the (remote) host can't do that any longer; or an error state might 822 * be cleared, to make the device behave identically whether or not 823 * power is maintained. 824 */ 825struct usb_gadget_driver { 826 char *function; 827 enum usb_device_speed speed; 828 void (*unbind)(struct usb_gadget *); 829 int (*setup)(struct usb_gadget *, 830 const struct usb_ctrlrequest *); 831 void (*disconnect)(struct usb_gadget *); 832 void (*suspend)(struct usb_gadget *); 833 void (*resume)(struct usb_gadget *); 834 835 /* FIXME support safe rmmod */ 836 struct device_driver driver; 837}; 838 839 840 841/*-------------------------------------------------------------------------*/ 842 843/* driver modules register and unregister, as usual. 844 * these calls must be made in a context that can sleep. 845 * 846 * these will usually be implemented directly by the hardware-dependent 847 * usb bus interface driver, which will only support a single driver. 848 */ 849 850/** 851 * usb_gadget_probe_driver - probe a gadget driver 852 * @driver: the driver being registered 853 * @bind: the driver's bind callback 854 * Context: can sleep 855 * 856 * Call this in your gadget driver's module initialization function, 857 * to tell the underlying usb controller driver about your driver. 858 * The @bind() function will be called to bind it to a gadget before this 859 * registration call returns. It's expected that the @bind() function will 860 * be in init sections. 861 */ 862int usb_gadget_probe_driver(struct usb_gadget_driver *driver, 863 int (*bind)(struct usb_gadget *)); 864 865/** 866 * usb_gadget_unregister_driver - unregister a gadget driver 867 * @driver:the driver being unregistered 868 * Context: can sleep 869 * 870 * Call this in your gadget driver's module cleanup function, 871 * to tell the underlying usb controller that your driver is 872 * going away. If the controller is connected to a USB host, 873 * it will first disconnect(). The driver is also requested 874 * to unbind() and clean up any device state, before this procedure 875 * finally returns. It's expected that the unbind() functions 876 * will in in exit sections, so may not be linked in some kernels. 877 */ 878int usb_gadget_unregister_driver(struct usb_gadget_driver *driver); 879 880extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget); 881extern void usb_del_gadget_udc(struct usb_gadget *gadget); 882 883/*-------------------------------------------------------------------------*/ 884 885/* utility to simplify dealing with string descriptors */ 886 887/** 888 * struct usb_string - wraps a C string and its USB id 889 * @id:the (nonzero) ID for this string 890 * @s:the string, in UTF-8 encoding 891 * 892 * If you're using usb_gadget_get_string(), use this to wrap a string 893 * together with its ID. 894 */ 895struct usb_string { 896 u8 id; 897 const char *s; 898}; 899 900/** 901 * struct usb_gadget_strings - a set of USB strings in a given language 902 * @language:identifies the strings' language (0x0409 for en-us) 903 * @strings:array of strings with their ids 904 * 905 * If you're using usb_gadget_get_string(), use this to wrap all the 906 * strings for a given language. 907 */ 908struct usb_gadget_strings { 909 u16 language; /* 0x0409 for en-us */ 910 struct usb_string *strings; 911}; 912 913/* put descriptor for string with that id into buf (buflen >= 256) */ 914int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf); 915 916/*-------------------------------------------------------------------------*/ 917 918/* utility to simplify managing config descriptors */ 919 920/* write vector of descriptors into buffer */ 921int usb_descriptor_fillbuf(void *, unsigned, 922 const struct usb_descriptor_header **); 923 924/* build config descriptor from single descriptor vector */ 925int usb_gadget_config_buf(const struct usb_config_descriptor *config, 926 void *buf, unsigned buflen, const struct usb_descriptor_header **desc); 927 928/* copy a NULL-terminated vector of descriptors */ 929struct usb_descriptor_header **usb_copy_descriptors( 930 struct usb_descriptor_header **); 931 932/** 933 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors() 934 * @v: vector of descriptors 935 */ 936static inline void usb_free_descriptors(struct usb_descriptor_header **v) 937{ 938 kfree(v); 939} 940 941/*-------------------------------------------------------------------------*/ 942 943/* utility wrapping a simple endpoint selection policy */ 944 945extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *, 946 struct usb_endpoint_descriptor *); 947 948 949extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *, 950 struct usb_endpoint_descriptor *, 951 struct usb_ss_ep_comp_descriptor *); 952 953extern void usb_ep_autoconfig_reset(struct usb_gadget *); 954 955#endif /* __LINUX_USB_GADGET_H */ 956