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