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