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Linux/include/linux/usb/gadget.h

  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/scatterlist.h>
 24 #include <linux/types.h>
 25 #include <linux/workqueue.h>
 26 #include <linux/usb/ch9.h>
 27 
 28 struct usb_ep;
 29 
 30 /**
 31  * struct usb_request - describes one i/o request
 32  * @buf: Buffer used for data.  Always provide this; some controllers
 33  *      only use PIO, or don't use DMA for some endpoints.
 34  * @dma: DMA address corresponding to 'buf'.  If you don't set this
 35  *      field, and the usb controller needs one, it is responsible
 36  *      for mapping and unmapping the buffer.
 37  * @sg: a scatterlist for SG-capable controllers.
 38  * @num_sgs: number of SG entries
 39  * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
 40  * @length: Length of that data
 41  * @stream_id: The stream id, when USB3.0 bulk streams are being used
 42  * @no_interrupt: If true, hints that no completion irq is needed.
 43  *      Helpful sometimes with deep request queues that are handled
 44  *      directly by DMA controllers.
 45  * @zero: If true, when writing data, makes the last packet be "short"
 46  *     by adding a zero length packet as needed;
 47  * @short_not_ok: When reading data, makes short packets be
 48  *     treated as errors (queue stops advancing till cleanup).
 49  * @complete: Function called when request completes, so this request and
 50  *      its buffer may be re-used.  The function will always be called with
 51  *      interrupts disabled, and it must not sleep.
 52  *      Reads terminate with a short packet, or when the buffer fills,
 53  *      whichever comes first.  When writes terminate, some data bytes
 54  *      will usually still be in flight (often in a hardware fifo).
 55  *      Errors (for reads or writes) stop the queue from advancing
 56  *      until the completion function returns, so that any transfers
 57  *      invalidated by the error may first be dequeued.
 58  * @context: For use by the completion callback
 59  * @list: For use by the gadget driver.
 60  * @status: Reports completion code, zero or a negative errno.
 61  *      Normally, faults block the transfer queue from advancing until
 62  *      the completion callback returns.
 63  *      Code "-ESHUTDOWN" indicates completion caused by device disconnect,
 64  *      or when the driver disabled the endpoint.
 65  * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
 66  *      transfers) this may be less than the requested length.  If the
 67  *      short_not_ok flag is set, short reads are treated as errors
 68  *      even when status otherwise indicates successful completion.
 69  *      Note that for writes (IN transfers) some data bytes may still
 70  *      reside in a device-side FIFO when the request is reported as
 71  *      complete.
 72  *
 73  * These are allocated/freed through the endpoint they're used with.  The
 74  * hardware's driver can add extra per-request data to the memory it returns,
 75  * which often avoids separate memory allocations (potential failures),
 76  * later when the request is queued.
 77  *
 78  * Request flags affect request handling, such as whether a zero length
 79  * packet is written (the "zero" flag), whether a short read should be
 80  * treated as an error (blocking request queue advance, the "short_not_ok"
 81  * flag), or hinting that an interrupt is not required (the "no_interrupt"
 82  * flag, for use with deep request queues).
 83  *
 84  * Bulk endpoints can use any size buffers, and can also be used for interrupt
 85  * transfers. interrupt-only endpoints can be much less functional.
 86  *
 87  * NOTE:  this is analogous to 'struct urb' on the host side, except that
 88  * it's thinner and promotes more pre-allocation.
 89  */
 90 
 91 struct usb_request {
 92         void                    *buf;
 93         unsigned                length;
 94         dma_addr_t              dma;
 95 
 96         struct scatterlist      *sg;
 97         unsigned                num_sgs;
 98         unsigned                num_mapped_sgs;
 99 
100         unsigned                stream_id:16;
101         unsigned                no_interrupt:1;
102         unsigned                zero:1;
103         unsigned                short_not_ok:1;
104 
105         void                    (*complete)(struct usb_ep *ep,
106                                         struct usb_request *req);
107         void                    *context;
108         struct list_head        list;
109 
110         int                     status;
111         unsigned                actual;
112 };
113 
114 /*-------------------------------------------------------------------------*/
115 
116 /* endpoint-specific parts of the api to the usb controller hardware.
117  * unlike the urb model, (de)multiplexing layers are not required.
118  * (so this api could slash overhead if used on the host side...)
119  *
120  * note that device side usb controllers commonly differ in how many
121  * endpoints they support, as well as their capabilities.
122  */
123 struct usb_ep_ops {
124         int (*enable) (struct usb_ep *ep,
125                 const struct usb_endpoint_descriptor *desc);
126         int (*disable) (struct usb_ep *ep);
127 
128         struct usb_request *(*alloc_request) (struct usb_ep *ep,
129                 gfp_t gfp_flags);
130         void (*free_request) (struct usb_ep *ep, struct usb_request *req);
131 
132         int (*queue) (struct usb_ep *ep, struct usb_request *req,
133                 gfp_t gfp_flags);
134         int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
135 
136         int (*set_halt) (struct usb_ep *ep, int value);
137         int (*set_wedge) (struct usb_ep *ep);
138 
139         int (*fifo_status) (struct usb_ep *ep);
140         void (*fifo_flush) (struct usb_ep *ep);
141 };
142 
143 /**
144  * struct usb_ep_caps - endpoint capabilities description
145  * @type_control:Endpoint supports control type (reserved for ep0).
146  * @type_iso:Endpoint supports isochronous transfers.
147  * @type_bulk:Endpoint supports bulk transfers.
148  * @type_int:Endpoint supports interrupt transfers.
149  * @dir_in:Endpoint supports IN direction.
150  * @dir_out:Endpoint supports OUT direction.
151  */
152 struct usb_ep_caps {
153         unsigned type_control:1;
154         unsigned type_iso:1;
155         unsigned type_bulk:1;
156         unsigned type_int:1;
157         unsigned dir_in:1;
158         unsigned dir_out:1;
159 };
160 
161 #define USB_EP_CAPS_TYPE_CONTROL     0x01
162 #define USB_EP_CAPS_TYPE_ISO         0x02
163 #define USB_EP_CAPS_TYPE_BULK        0x04
164 #define USB_EP_CAPS_TYPE_INT         0x08
165 #define USB_EP_CAPS_TYPE_ALL \
166         (USB_EP_CAPS_TYPE_ISO | USB_EP_CAPS_TYPE_BULK | USB_EP_CAPS_TYPE_INT)
167 #define USB_EP_CAPS_DIR_IN           0x01
168 #define USB_EP_CAPS_DIR_OUT          0x02
169 #define USB_EP_CAPS_DIR_ALL  (USB_EP_CAPS_DIR_IN | USB_EP_CAPS_DIR_OUT)
170 
171 #define USB_EP_CAPS(_type, _dir) \
172         { \
173                 .type_control = !!(_type & USB_EP_CAPS_TYPE_CONTROL), \
174                 .type_iso = !!(_type & USB_EP_CAPS_TYPE_ISO), \
175                 .type_bulk = !!(_type & USB_EP_CAPS_TYPE_BULK), \
176                 .type_int = !!(_type & USB_EP_CAPS_TYPE_INT), \
177                 .dir_in = !!(_dir & USB_EP_CAPS_DIR_IN), \
178                 .dir_out = !!(_dir & USB_EP_CAPS_DIR_OUT), \
179         }
180 
181 /**
182  * struct usb_ep - device side representation of USB endpoint
183  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
184  * @ops: Function pointers used to access hardware-specific operations.
185  * @ep_list:the gadget's ep_list holds all of its endpoints
186  * @caps:The structure describing types and directions supported by endoint.
187  * @maxpacket:The maximum packet size used on this endpoint.  The initial
188  *      value can sometimes be reduced (hardware allowing), according to
189  *      the endpoint descriptor used to configure the endpoint.
190  * @maxpacket_limit:The maximum packet size value which can be handled by this
191  *      endpoint. It's set once by UDC driver when endpoint is initialized, and
192  *      should not be changed. Should not be confused with maxpacket.
193  * @max_streams: The maximum number of streams supported
194  *      by this EP (0 - 16, actual number is 2^n)
195  * @mult: multiplier, 'mult' value for SS Isoc EPs
196  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
197  * @driver_data:for use by the gadget driver.
198  * @address: used to identify the endpoint when finding descriptor that
199  *      matches connection speed
200  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
201  *      enabled and remains valid until the endpoint is disabled.
202  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
203  *      descriptor that is used to configure the endpoint
204  *
205  * the bus controller driver lists all the general purpose endpoints in
206  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
207  * and is accessed only in response to a driver setup() callback.
208  */
209 
210 struct usb_ep {
211         void                    *driver_data;
212 
213         const char              *name;
214         const struct usb_ep_ops *ops;
215         struct list_head        ep_list;
216         struct usb_ep_caps      caps;
217         bool                    claimed;
218         bool                    enabled;
219         unsigned                maxpacket:16;
220         unsigned                maxpacket_limit:16;
221         unsigned                max_streams:16;
222         unsigned                mult:2;
223         unsigned                maxburst:5;
224         u8                      address;
225         const struct usb_endpoint_descriptor    *desc;
226         const struct usb_ss_ep_comp_descriptor  *comp_desc;
227 };
228 
229 /*-------------------------------------------------------------------------*/
230 
231 /**
232  * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
233  * @ep:the endpoint being configured
234  * @maxpacket_limit:value of maximum packet size limit
235  *
236  * This function should be used only in UDC drivers to initialize endpoint
237  * (usually in probe function).
238  */
239 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
240                                               unsigned maxpacket_limit)
241 {
242         ep->maxpacket_limit = maxpacket_limit;
243         ep->maxpacket = maxpacket_limit;
244 }
245 
246 /**
247  * usb_ep_enable - configure endpoint, making it usable
248  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
249  *      drivers discover endpoints through the ep_list of a usb_gadget.
250  *
251  * When configurations are set, or when interface settings change, the driver
252  * will enable or disable the relevant endpoints.  while it is enabled, an
253  * endpoint may be used for i/o until the driver receives a disconnect() from
254  * the host or until the endpoint is disabled.
255  *
256  * the ep0 implementation (which calls this routine) must ensure that the
257  * hardware capabilities of each endpoint match the descriptor provided
258  * for it.  for example, an endpoint named "ep2in-bulk" would be usable
259  * for interrupt transfers as well as bulk, but it likely couldn't be used
260  * for iso transfers or for endpoint 14.  some endpoints are fully
261  * configurable, with more generic names like "ep-a".  (remember that for
262  * USB, "in" means "towards the USB master".)
263  *
264  * returns zero, or a negative error code.
265  */
266 static inline int usb_ep_enable(struct usb_ep *ep)
267 {
268         int ret;
269 
270         if (ep->enabled)
271                 return 0;
272 
273         ret = ep->ops->enable(ep, ep->desc);
274         if (ret)
275                 return ret;
276 
277         ep->enabled = true;
278 
279         return 0;
280 }
281 
282 /**
283  * usb_ep_disable - endpoint is no longer usable
284  * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
285  *
286  * no other task may be using this endpoint when this is called.
287  * any pending and uncompleted requests will complete with status
288  * indicating disconnect (-ESHUTDOWN) before this call returns.
289  * gadget drivers must call usb_ep_enable() again before queueing
290  * requests to the endpoint.
291  *
292  * returns zero, or a negative error code.
293  */
294 static inline int usb_ep_disable(struct usb_ep *ep)
295 {
296         int ret;
297 
298         if (!ep->enabled)
299                 return 0;
300 
301         ret = ep->ops->disable(ep);
302         if (ret)
303                 return ret;
304 
305         ep->enabled = false;
306 
307         return 0;
308 }
309 
310 /**
311  * usb_ep_alloc_request - allocate a request object to use with this endpoint
312  * @ep:the endpoint to be used with with the request
313  * @gfp_flags:GFP_* flags to use
314  *
315  * Request objects must be allocated with this call, since they normally
316  * need controller-specific setup and may even need endpoint-specific
317  * resources such as allocation of DMA descriptors.
318  * Requests may be submitted with usb_ep_queue(), and receive a single
319  * completion callback.  Free requests with usb_ep_free_request(), when
320  * they are no longer needed.
321  *
322  * Returns the request, or null if one could not be allocated.
323  */
324 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
325                                                        gfp_t gfp_flags)
326 {
327         return ep->ops->alloc_request(ep, gfp_flags);
328 }
329 
330 /**
331  * usb_ep_free_request - frees a request object
332  * @ep:the endpoint associated with the request
333  * @req:the request being freed
334  *
335  * Reverses the effect of usb_ep_alloc_request().
336  * Caller guarantees the request is not queued, and that it will
337  * no longer be requeued (or otherwise used).
338  */
339 static inline void usb_ep_free_request(struct usb_ep *ep,
340                                        struct usb_request *req)
341 {
342         ep->ops->free_request(ep, req);
343 }
344 
345 /**
346  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
347  * @ep:the endpoint associated with the request
348  * @req:the request being submitted
349  * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
350  *      pre-allocate all necessary memory with the request.
351  *
352  * This tells the device controller to perform the specified request through
353  * that endpoint (reading or writing a buffer).  When the request completes,
354  * including being canceled by usb_ep_dequeue(), the request's completion
355  * routine is called to return the request to the driver.  Any endpoint
356  * (except control endpoints like ep0) may have more than one transfer
357  * request queued; they complete in FIFO order.  Once a gadget driver
358  * submits a request, that request may not be examined or modified until it
359  * is given back to that driver through the completion callback.
360  *
361  * Each request is turned into one or more packets.  The controller driver
362  * never merges adjacent requests into the same packet.  OUT transfers
363  * will sometimes use data that's already buffered in the hardware.
364  * Drivers can rely on the fact that the first byte of the request's buffer
365  * always corresponds to the first byte of some USB packet, for both
366  * IN and OUT transfers.
367  *
368  * Bulk endpoints can queue any amount of data; the transfer is packetized
369  * automatically.  The last packet will be short if the request doesn't fill it
370  * out completely.  Zero length packets (ZLPs) should be avoided in portable
371  * protocols since not all usb hardware can successfully handle zero length
372  * packets.  (ZLPs may be explicitly written, and may be implicitly written if
373  * the request 'zero' flag is set.)  Bulk endpoints may also be used
374  * for interrupt transfers; but the reverse is not true, and some endpoints
375  * won't support every interrupt transfer.  (Such as 768 byte packets.)
376  *
377  * Interrupt-only endpoints are less functional than bulk endpoints, for
378  * example by not supporting queueing or not handling buffers that are
379  * larger than the endpoint's maxpacket size.  They may also treat data
380  * toggle differently.
381  *
382  * Control endpoints ... after getting a setup() callback, the driver queues
383  * one response (even if it would be zero length).  That enables the
384  * status ack, after transferring data as specified in the response.  Setup
385  * functions may return negative error codes to generate protocol stalls.
386  * (Note that some USB device controllers disallow protocol stall responses
387  * in some cases.)  When control responses are deferred (the response is
388  * written after the setup callback returns), then usb_ep_set_halt() may be
389  * used on ep0 to trigger protocol stalls.  Depending on the controller,
390  * it may not be possible to trigger a status-stage protocol stall when the
391  * data stage is over, that is, from within the response's completion
392  * routine.
393  *
394  * For periodic endpoints, like interrupt or isochronous ones, the usb host
395  * arranges to poll once per interval, and the gadget driver usually will
396  * have queued some data to transfer at that time.
397  *
398  * Returns zero, or a negative error code.  Endpoints that are not enabled
399  * report errors; errors will also be
400  * reported when the usb peripheral is disconnected.
401  */
402 static inline int usb_ep_queue(struct usb_ep *ep,
403                                struct usb_request *req, gfp_t gfp_flags)
404 {
405         return ep->ops->queue(ep, req, gfp_flags);
406 }
407 
408 /**
409  * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
410  * @ep:the endpoint associated with the request
411  * @req:the request being canceled
412  *
413  * If the request is still active on the endpoint, it is dequeued and its
414  * completion routine is called (with status -ECONNRESET); else a negative
415  * error code is returned. This is guaranteed to happen before the call to
416  * usb_ep_dequeue() returns.
417  *
418  * Note that some hardware can't clear out write fifos (to unlink the request
419  * at the head of the queue) except as part of disconnecting from usb. Such
420  * restrictions prevent drivers from supporting configuration changes,
421  * even to configuration zero (a "chapter 9" requirement).
422  */
423 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
424 {
425         return ep->ops->dequeue(ep, req);
426 }
427 
428 /**
429  * usb_ep_set_halt - sets the endpoint halt feature.
430  * @ep: the non-isochronous endpoint being stalled
431  *
432  * Use this to stall an endpoint, perhaps as an error report.
433  * Except for control endpoints,
434  * the endpoint stays halted (will not stream any data) until the host
435  * clears this feature; drivers may need to empty the endpoint's request
436  * queue first, to make sure no inappropriate transfers happen.
437  *
438  * Note that while an endpoint CLEAR_FEATURE will be invisible to the
439  * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
440  * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
441  * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
442  *
443  * Returns zero, or a negative error code.  On success, this call sets
444  * underlying hardware state that blocks data transfers.
445  * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
446  * transfer requests are still queued, or if the controller hardware
447  * (usually a FIFO) still holds bytes that the host hasn't collected.
448  */
449 static inline int usb_ep_set_halt(struct usb_ep *ep)
450 {
451         return ep->ops->set_halt(ep, 1);
452 }
453 
454 /**
455  * usb_ep_clear_halt - clears endpoint halt, and resets toggle
456  * @ep:the bulk or interrupt endpoint being reset
457  *
458  * Use this when responding to the standard usb "set interface" request,
459  * for endpoints that aren't reconfigured, after clearing any other state
460  * in the endpoint's i/o queue.
461  *
462  * Returns zero, or a negative error code.  On success, this call clears
463  * the underlying hardware state reflecting endpoint halt and data toggle.
464  * Note that some hardware can't support this request (like pxa2xx_udc),
465  * and accordingly can't correctly implement interface altsettings.
466  */
467 static inline int usb_ep_clear_halt(struct usb_ep *ep)
468 {
469         return ep->ops->set_halt(ep, 0);
470 }
471 
472 /**
473  * usb_ep_set_wedge - sets the halt feature and ignores clear requests
474  * @ep: the endpoint being wedged
475  *
476  * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
477  * requests. If the gadget driver clears the halt status, it will
478  * automatically unwedge the endpoint.
479  *
480  * Returns zero on success, else negative errno.
481  */
482 static inline int
483 usb_ep_set_wedge(struct usb_ep *ep)
484 {
485         if (ep->ops->set_wedge)
486                 return ep->ops->set_wedge(ep);
487         else
488                 return ep->ops->set_halt(ep, 1);
489 }
490 
491 /**
492  * usb_ep_fifo_status - returns number of bytes in fifo, or error
493  * @ep: the endpoint whose fifo status is being checked.
494  *
495  * FIFO endpoints may have "unclaimed data" in them in certain cases,
496  * such as after aborted transfers.  Hosts may not have collected all
497  * the IN data written by the gadget driver (and reported by a request
498  * completion).  The gadget driver may not have collected all the data
499  * written OUT to it by the host.  Drivers that need precise handling for
500  * fault reporting or recovery may need to use this call.
501  *
502  * This returns the number of such bytes in the fifo, or a negative
503  * errno if the endpoint doesn't use a FIFO or doesn't support such
504  * precise handling.
505  */
506 static inline int usb_ep_fifo_status(struct usb_ep *ep)
507 {
508         if (ep->ops->fifo_status)
509                 return ep->ops->fifo_status(ep);
510         else
511                 return -EOPNOTSUPP;
512 }
513 
514 /**
515  * usb_ep_fifo_flush - flushes contents of a fifo
516  * @ep: the endpoint whose fifo is being flushed.
517  *
518  * This call may be used to flush the "unclaimed data" that may exist in
519  * an endpoint fifo after abnormal transaction terminations.  The call
520  * must never be used except when endpoint is not being used for any
521  * protocol translation.
522  */
523 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
524 {
525         if (ep->ops->fifo_flush)
526                 ep->ops->fifo_flush(ep);
527 }
528 
529 
530 /*-------------------------------------------------------------------------*/
531 
532 struct usb_dcd_config_params {
533         __u8  bU1devExitLat;    /* U1 Device exit Latency */
534 #define USB_DEFAULT_U1_DEV_EXIT_LAT     0x01    /* Less then 1 microsec */
535         __le16 bU2DevExitLat;   /* U2 Device exit Latency */
536 #define USB_DEFAULT_U2_DEV_EXIT_LAT     0x1F4   /* Less then 500 microsec */
537 };
538 
539 
540 struct usb_gadget;
541 struct usb_gadget_driver;
542 struct usb_udc;
543 
544 /* the rest of the api to the controller hardware: device operations,
545  * which don't involve endpoints (or i/o).
546  */
547 struct usb_gadget_ops {
548         int     (*get_frame)(struct usb_gadget *);
549         int     (*wakeup)(struct usb_gadget *);
550         int     (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
551         int     (*vbus_session) (struct usb_gadget *, int is_active);
552         int     (*vbus_draw) (struct usb_gadget *, unsigned mA);
553         int     (*pullup) (struct usb_gadget *, int is_on);
554         int     (*ioctl)(struct usb_gadget *,
555                                 unsigned code, unsigned long param);
556         void    (*get_config_params)(struct usb_dcd_config_params *);
557         int     (*udc_start)(struct usb_gadget *,
558                         struct usb_gadget_driver *);
559         int     (*udc_stop)(struct usb_gadget *);
560         struct usb_ep *(*match_ep)(struct usb_gadget *,
561                         struct usb_endpoint_descriptor *,
562                         struct usb_ss_ep_comp_descriptor *);
563 };
564 
565 /**
566  * struct usb_gadget - represents a usb slave device
567  * @work: (internal use) Workqueue to be used for sysfs_notify()
568  * @udc: struct usb_udc pointer for this gadget
569  * @ops: Function pointers used to access hardware-specific operations.
570  * @ep0: Endpoint zero, used when reading or writing responses to
571  *      driver setup() requests
572  * @ep_list: List of other endpoints supported by the device.
573  * @speed: Speed of current connection to USB host.
574  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
575  *      and all slower speeds.
576  * @state: the state we are now (attached, suspended, configured, etc)
577  * @name: Identifies the controller hardware type.  Used in diagnostics
578  *      and sometimes configuration.
579  * @dev: Driver model state for this abstract device.
580  * @out_epnum: last used out ep number
581  * @in_epnum: last used in ep number
582  * @otg_caps: OTG capabilities of this gadget.
583  * @sg_supported: true if we can handle scatter-gather
584  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
585  *      gadget driver must provide a USB OTG descriptor.
586  * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
587  *      is in the Mini-AB jack, and HNP has been used to switch roles
588  *      so that the "A" device currently acts as A-Peripheral, not A-Host.
589  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
590  *      supports HNP at this port.
591  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
592  *      only supports HNP on a different root port.
593  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
594  *      enabled HNP support.
595  * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
596  *      MaxPacketSize.
597  * @is_selfpowered: if the gadget is self-powered.
598  * @deactivated: True if gadget is deactivated - in deactivated state it cannot
599  *      be connected.
600  * @connected: True if gadget is connected.
601  *
602  * Gadgets have a mostly-portable "gadget driver" implementing device
603  * functions, handling all usb configurations and interfaces.  Gadget
604  * drivers talk to hardware-specific code indirectly, through ops vectors.
605  * That insulates the gadget driver from hardware details, and packages
606  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
607  * and "usb_ep" interfaces provide that insulation from the hardware.
608  *
609  * Except for the driver data, all fields in this structure are
610  * read-only to the gadget driver.  That driver data is part of the
611  * "driver model" infrastructure in 2.6 (and later) kernels, and for
612  * earlier systems is grouped in a similar structure that's not known
613  * to the rest of the kernel.
614  *
615  * Values of the three OTG device feature flags are updated before the
616  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
617  * driver suspend() calls.  They are valid only when is_otg, and when the
618  * device is acting as a B-Peripheral (so is_a_peripheral is false).
619  */
620 struct usb_gadget {
621         struct work_struct              work;
622         struct usb_udc                  *udc;
623         /* readonly to gadget driver */
624         const struct usb_gadget_ops     *ops;
625         struct usb_ep                   *ep0;
626         struct list_head                ep_list;        /* of usb_ep */
627         enum usb_device_speed           speed;
628         enum usb_device_speed           max_speed;
629         enum usb_device_state           state;
630         const char                      *name;
631         struct device                   dev;
632         unsigned                        out_epnum;
633         unsigned                        in_epnum;
634         struct usb_otg_caps             *otg_caps;
635 
636         unsigned                        sg_supported:1;
637         unsigned                        is_otg:1;
638         unsigned                        is_a_peripheral:1;
639         unsigned                        b_hnp_enable:1;
640         unsigned                        a_hnp_support:1;
641         unsigned                        a_alt_hnp_support:1;
642         unsigned                        quirk_ep_out_aligned_size:1;
643         unsigned                        quirk_altset_not_supp:1;
644         unsigned                        quirk_stall_not_supp:1;
645         unsigned                        quirk_zlp_not_supp:1;
646         unsigned                        is_selfpowered:1;
647         unsigned                        deactivated:1;
648         unsigned                        connected:1;
649 };
650 #define work_to_gadget(w)       (container_of((w), struct usb_gadget, work))
651 
652 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
653         { dev_set_drvdata(&gadget->dev, data); }
654 static inline void *get_gadget_data(struct usb_gadget *gadget)
655         { return dev_get_drvdata(&gadget->dev); }
656 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
657 {
658         return container_of(dev, struct usb_gadget, dev);
659 }
660 
661 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
662 #define gadget_for_each_ep(tmp, gadget) \
663         list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
664 
665 /**
666  * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
667  *      requires quirk_ep_out_aligned_size, otherwise reguens len.
668  * @g: controller to check for quirk
669  * @ep: the endpoint whose maxpacketsize is used to align @len
670  * @len: buffer size's length to align to @ep's maxpacketsize
671  *
672  * This helper is used in case it's required for any reason to check and maybe
673  * align buffer's size to an ep's maxpacketsize.
674  */
675 static inline size_t
676 usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
677 {
678         return !g->quirk_ep_out_aligned_size ? len :
679                         round_up(len, (size_t)ep->desc->wMaxPacketSize);
680 }
681 
682 /**
683  * gadget_is_altset_supported - return true iff the hardware supports
684  *      altsettings
685  * @g: controller to check for quirk
686  */
687 static inline int gadget_is_altset_supported(struct usb_gadget *g)
688 {
689         return !g->quirk_altset_not_supp;
690 }
691 
692 /**
693  * gadget_is_stall_supported - return true iff the hardware supports stalling
694  * @g: controller to check for quirk
695  */
696 static inline int gadget_is_stall_supported(struct usb_gadget *g)
697 {
698         return !g->quirk_stall_not_supp;
699 }
700 
701 /**
702  * gadget_is_zlp_supported - return true iff the hardware supports zlp
703  * @g: controller to check for quirk
704  */
705 static inline int gadget_is_zlp_supported(struct usb_gadget *g)
706 {
707         return !g->quirk_zlp_not_supp;
708 }
709 
710 /**
711  * gadget_is_dualspeed - return true iff the hardware handles high speed
712  * @g: controller that might support both high and full speeds
713  */
714 static inline int gadget_is_dualspeed(struct usb_gadget *g)
715 {
716         return g->max_speed >= USB_SPEED_HIGH;
717 }
718 
719 /**
720  * gadget_is_superspeed() - return true if the hardware handles superspeed
721  * @g: controller that might support superspeed
722  */
723 static inline int gadget_is_superspeed(struct usb_gadget *g)
724 {
725         return g->max_speed >= USB_SPEED_SUPER;
726 }
727 
728 /**
729  * gadget_is_otg - return true iff the hardware is OTG-ready
730  * @g: controller that might have a Mini-AB connector
731  *
732  * This is a runtime test, since kernels with a USB-OTG stack sometimes
733  * run on boards which only have a Mini-B (or Mini-A) connector.
734  */
735 static inline int gadget_is_otg(struct usb_gadget *g)
736 {
737 #ifdef CONFIG_USB_OTG
738         return g->is_otg;
739 #else
740         return 0;
741 #endif
742 }
743 
744 /**
745  * usb_gadget_frame_number - returns the current frame number
746  * @gadget: controller that reports the frame number
747  *
748  * Returns the usb frame number, normally eleven bits from a SOF packet,
749  * or negative errno if this device doesn't support this capability.
750  */
751 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
752 {
753         return gadget->ops->get_frame(gadget);
754 }
755 
756 /**
757  * usb_gadget_wakeup - tries to wake up the host connected to this gadget
758  * @gadget: controller used to wake up the host
759  *
760  * Returns zero on success, else negative error code if the hardware
761  * doesn't support such attempts, or its support has not been enabled
762  * by the usb host.  Drivers must return device descriptors that report
763  * their ability to support this, or hosts won't enable it.
764  *
765  * This may also try to use SRP to wake the host and start enumeration,
766  * even if OTG isn't otherwise in use.  OTG devices may also start
767  * remote wakeup even when hosts don't explicitly enable it.
768  */
769 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
770 {
771         if (!gadget->ops->wakeup)
772                 return -EOPNOTSUPP;
773         return gadget->ops->wakeup(gadget);
774 }
775 
776 /**
777  * usb_gadget_set_selfpowered - sets the device selfpowered feature.
778  * @gadget:the device being declared as self-powered
779  *
780  * this affects the device status reported by the hardware driver
781  * to reflect that it now has a local power supply.
782  *
783  * returns zero on success, else negative errno.
784  */
785 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
786 {
787         if (!gadget->ops->set_selfpowered)
788                 return -EOPNOTSUPP;
789         return gadget->ops->set_selfpowered(gadget, 1);
790 }
791 
792 /**
793  * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
794  * @gadget:the device being declared as bus-powered
795  *
796  * this affects the device status reported by the hardware driver.
797  * some hardware may not support bus-powered operation, in which
798  * case this feature's value can never change.
799  *
800  * returns zero on success, else negative errno.
801  */
802 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
803 {
804         if (!gadget->ops->set_selfpowered)
805                 return -EOPNOTSUPP;
806         return gadget->ops->set_selfpowered(gadget, 0);
807 }
808 
809 /**
810  * usb_gadget_vbus_connect - Notify controller that VBUS is powered
811  * @gadget:The device which now has VBUS power.
812  * Context: can sleep
813  *
814  * This call is used by a driver for an external transceiver (or GPIO)
815  * that detects a VBUS power session starting.  Common responses include
816  * resuming the controller, activating the D+ (or D-) pullup to let the
817  * host detect that a USB device is attached, and starting to draw power
818  * (8mA or possibly more, especially after SET_CONFIGURATION).
819  *
820  * Returns zero on success, else negative errno.
821  */
822 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
823 {
824         if (!gadget->ops->vbus_session)
825                 return -EOPNOTSUPP;
826         return gadget->ops->vbus_session(gadget, 1);
827 }
828 
829 /**
830  * usb_gadget_vbus_draw - constrain controller's VBUS power usage
831  * @gadget:The device whose VBUS usage is being described
832  * @mA:How much current to draw, in milliAmperes.  This should be twice
833  *      the value listed in the configuration descriptor bMaxPower field.
834  *
835  * This call is used by gadget drivers during SET_CONFIGURATION calls,
836  * reporting how much power the device may consume.  For example, this
837  * could affect how quickly batteries are recharged.
838  *
839  * Returns zero on success, else negative errno.
840  */
841 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
842 {
843         if (!gadget->ops->vbus_draw)
844                 return -EOPNOTSUPP;
845         return gadget->ops->vbus_draw(gadget, mA);
846 }
847 
848 /**
849  * usb_gadget_vbus_disconnect - notify controller about VBUS session end
850  * @gadget:the device whose VBUS supply is being described
851  * Context: can sleep
852  *
853  * This call is used by a driver for an external transceiver (or GPIO)
854  * that detects a VBUS power session ending.  Common responses include
855  * reversing everything done in usb_gadget_vbus_connect().
856  *
857  * Returns zero on success, else negative errno.
858  */
859 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
860 {
861         if (!gadget->ops->vbus_session)
862                 return -EOPNOTSUPP;
863         return gadget->ops->vbus_session(gadget, 0);
864 }
865 
866 /**
867  * usb_gadget_connect - software-controlled connect to USB host
868  * @gadget:the peripheral being connected
869  *
870  * Enables the D+ (or potentially D-) pullup.  The host will start
871  * enumerating this gadget when the pullup is active and a VBUS session
872  * is active (the link is powered).  This pullup is always enabled unless
873  * usb_gadget_disconnect() has been used to disable it.
874  *
875  * Returns zero on success, else negative errno.
876  */
877 static inline int usb_gadget_connect(struct usb_gadget *gadget)
878 {
879         int ret;
880 
881         if (!gadget->ops->pullup)
882                 return -EOPNOTSUPP;
883 
884         if (gadget->deactivated) {
885                 /*
886                  * If gadget is deactivated we only save new state.
887                  * Gadget will be connected automatically after activation.
888                  */
889                 gadget->connected = true;
890                 return 0;
891         }
892 
893         ret = gadget->ops->pullup(gadget, 1);
894         if (!ret)
895                 gadget->connected = 1;
896         return ret;
897 }
898 
899 /**
900  * usb_gadget_disconnect - software-controlled disconnect from USB host
901  * @gadget:the peripheral being disconnected
902  *
903  * Disables the D+ (or potentially D-) pullup, which the host may see
904  * as a disconnect (when a VBUS session is active).  Not all systems
905  * support software pullup controls.
906  *
907  * Returns zero on success, else negative errno.
908  */
909 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
910 {
911         int ret;
912 
913         if (!gadget->ops->pullup)
914                 return -EOPNOTSUPP;
915 
916         if (gadget->deactivated) {
917                 /*
918                  * If gadget is deactivated we only save new state.
919                  * Gadget will stay disconnected after activation.
920                  */
921                 gadget->connected = false;
922                 return 0;
923         }
924 
925         ret = gadget->ops->pullup(gadget, 0);
926         if (!ret)
927                 gadget->connected = 0;
928         return ret;
929 }
930 
931 /**
932  * usb_gadget_deactivate - deactivate function which is not ready to work
933  * @gadget: the peripheral being deactivated
934  *
935  * This routine may be used during the gadget driver bind() call to prevent
936  * the peripheral from ever being visible to the USB host, unless later
937  * usb_gadget_activate() is called.  For example, user mode components may
938  * need to be activated before the system can talk to hosts.
939  *
940  * Returns zero on success, else negative errno.
941  */
942 static inline int usb_gadget_deactivate(struct usb_gadget *gadget)
943 {
944         int ret;
945 
946         if (gadget->deactivated)
947                 return 0;
948 
949         if (gadget->connected) {
950                 ret = usb_gadget_disconnect(gadget);
951                 if (ret)
952                         return ret;
953                 /*
954                  * If gadget was being connected before deactivation, we want
955                  * to reconnect it in usb_gadget_activate().
956                  */
957                 gadget->connected = true;
958         }
959         gadget->deactivated = true;
960 
961         return 0;
962 }
963 
964 /**
965  * usb_gadget_activate - activate function which is not ready to work
966  * @gadget: the peripheral being activated
967  *
968  * This routine activates gadget which was previously deactivated with
969  * usb_gadget_deactivate() call. It calls usb_gadget_connect() if needed.
970  *
971  * Returns zero on success, else negative errno.
972  */
973 static inline int usb_gadget_activate(struct usb_gadget *gadget)
974 {
975         if (!gadget->deactivated)
976                 return 0;
977 
978         gadget->deactivated = false;
979 
980         /*
981          * If gadget has been connected before deactivation, or became connected
982          * while it was being deactivated, we call usb_gadget_connect().
983          */
984         if (gadget->connected)
985                 return usb_gadget_connect(gadget);
986 
987         return 0;
988 }
989 
990 /*-------------------------------------------------------------------------*/
991 
992 /**
993  * struct usb_gadget_driver - driver for usb 'slave' devices
994  * @function: String describing the gadget's function
995  * @max_speed: Highest speed the driver handles.
996  * @setup: Invoked for ep0 control requests that aren't handled by
997  *      the hardware level driver. Most calls must be handled by
998  *      the gadget driver, including descriptor and configuration
999  *      management.  The 16 bit members of the setup data are in
1000  *      USB byte order. Called in_interrupt; this may not sleep.  Driver
1001  *      queues a response to ep0, or returns negative to stall.
1002  * @disconnect: Invoked after all transfers have been stopped,
1003  *      when the host is disconnected.  May be called in_interrupt; this
1004  *      may not sleep.  Some devices can't detect disconnect, so this might
1005  *      not be called except as part of controller shutdown.
1006  * @bind: the driver's bind callback
1007  * @unbind: Invoked when the driver is unbound from a gadget,
1008  *      usually from rmmod (after a disconnect is reported).
1009  *      Called in a context that permits sleeping.
1010  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
1011  * @resume: Invoked on USB resume.  May be called in_interrupt.
1012  * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
1013  *      and should be called in_interrupt.
1014  * @driver: Driver model state for this driver.
1015  *
1016  * Devices are disabled till a gadget driver successfully bind()s, which
1017  * means the driver will handle setup() requests needed to enumerate (and
1018  * meet "chapter 9" requirements) then do some useful work.
1019  *
1020  * If gadget->is_otg is true, the gadget driver must provide an OTG
1021  * descriptor during enumeration, or else fail the bind() call.  In such
1022  * cases, no USB traffic may flow until both bind() returns without
1023  * having called usb_gadget_disconnect(), and the USB host stack has
1024  * initialized.
1025  *
1026  * Drivers use hardware-specific knowledge to configure the usb hardware.
1027  * endpoint addressing is only one of several hardware characteristics that
1028  * are in descriptors the ep0 implementation returns from setup() calls.
1029  *
1030  * Except for ep0 implementation, most driver code shouldn't need change to
1031  * run on top of different usb controllers.  It'll use endpoints set up by
1032  * that ep0 implementation.
1033  *
1034  * The usb controller driver handles a few standard usb requests.  Those
1035  * include set_address, and feature flags for devices, interfaces, and
1036  * endpoints (the get_status, set_feature, and clear_feature requests).
1037  *
1038  * Accordingly, the driver's setup() callback must always implement all
1039  * get_descriptor requests, returning at least a device descriptor and
1040  * a configuration descriptor.  Drivers must make sure the endpoint
1041  * descriptors match any hardware constraints. Some hardware also constrains
1042  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
1043  *
1044  * The driver's setup() callback must also implement set_configuration,
1045  * and should also implement set_interface, get_configuration, and
1046  * get_interface.  Setting a configuration (or interface) is where
1047  * endpoints should be activated or (config 0) shut down.
1048  *
1049  * (Note that only the default control endpoint is supported.  Neither
1050  * hosts nor devices generally support control traffic except to ep0.)
1051  *
1052  * Most devices will ignore USB suspend/resume operations, and so will
1053  * not provide those callbacks.  However, some may need to change modes
1054  * when the host is not longer directing those activities.  For example,
1055  * local controls (buttons, dials, etc) may need to be re-enabled since
1056  * the (remote) host can't do that any longer; or an error state might
1057  * be cleared, to make the device behave identically whether or not
1058  * power is maintained.
1059  */
1060 struct usb_gadget_driver {
1061         char                    *function;
1062         enum usb_device_speed   max_speed;
1063         int                     (*bind)(struct usb_gadget *gadget,
1064                                         struct usb_gadget_driver *driver);
1065         void                    (*unbind)(struct usb_gadget *);
1066         int                     (*setup)(struct usb_gadget *,
1067                                         const struct usb_ctrlrequest *);
1068         void                    (*disconnect)(struct usb_gadget *);
1069         void                    (*suspend)(struct usb_gadget *);
1070         void                    (*resume)(struct usb_gadget *);
1071         void                    (*reset)(struct usb_gadget *);
1072 
1073         /* FIXME support safe rmmod */
1074         struct device_driver    driver;
1075 };
1076 
1077 
1078 
1079 /*-------------------------------------------------------------------------*/
1080 
1081 /* driver modules register and unregister, as usual.
1082  * these calls must be made in a context that can sleep.
1083  *
1084  * these will usually be implemented directly by the hardware-dependent
1085  * usb bus interface driver, which will only support a single driver.
1086  */
1087 
1088 /**
1089  * usb_gadget_probe_driver - probe a gadget driver
1090  * @driver: the driver being registered
1091  * Context: can sleep
1092  *
1093  * Call this in your gadget driver's module initialization function,
1094  * to tell the underlying usb controller driver about your driver.
1095  * The @bind() function will be called to bind it to a gadget before this
1096  * registration call returns.  It's expected that the @bind() function will
1097  * be in init sections.
1098  */
1099 int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
1100 
1101 /**
1102  * usb_gadget_unregister_driver - unregister a gadget driver
1103  * @driver:the driver being unregistered
1104  * Context: can sleep
1105  *
1106  * Call this in your gadget driver's module cleanup function,
1107  * to tell the underlying usb controller that your driver is
1108  * going away.  If the controller is connected to a USB host,
1109  * it will first disconnect().  The driver is also requested
1110  * to unbind() and clean up any device state, before this procedure
1111  * finally returns.  It's expected that the unbind() functions
1112  * will in in exit sections, so may not be linked in some kernels.
1113  */
1114 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
1115 
1116 extern int usb_add_gadget_udc_release(struct device *parent,
1117                 struct usb_gadget *gadget, void (*release)(struct device *dev));
1118 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
1119 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
1120 extern int usb_udc_attach_driver(const char *name,
1121                 struct usb_gadget_driver *driver);
1122 
1123 /*-------------------------------------------------------------------------*/
1124 
1125 /* utility to simplify dealing with string descriptors */
1126 
1127 /**
1128  * struct usb_string - wraps a C string and its USB id
1129  * @id:the (nonzero) ID for this string
1130  * @s:the string, in UTF-8 encoding
1131  *
1132  * If you're using usb_gadget_get_string(), use this to wrap a string
1133  * together with its ID.
1134  */
1135 struct usb_string {
1136         u8                      id;
1137         const char              *s;
1138 };
1139 
1140 /**
1141  * struct usb_gadget_strings - a set of USB strings in a given language
1142  * @language:identifies the strings' language (0x0409 for en-us)
1143  * @strings:array of strings with their ids
1144  *
1145  * If you're using usb_gadget_get_string(), use this to wrap all the
1146  * strings for a given language.
1147  */
1148 struct usb_gadget_strings {
1149         u16                     language;       /* 0x0409 for en-us */
1150         struct usb_string       *strings;
1151 };
1152 
1153 struct usb_gadget_string_container {
1154         struct list_head        list;
1155         u8                      *stash[0];
1156 };
1157 
1158 /* put descriptor for string with that id into buf (buflen >= 256) */
1159 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
1160 
1161 /*-------------------------------------------------------------------------*/
1162 
1163 /* utility to simplify managing config descriptors */
1164 
1165 /* write vector of descriptors into buffer */
1166 int usb_descriptor_fillbuf(void *, unsigned,
1167                 const struct usb_descriptor_header **);
1168 
1169 /* build config descriptor from single descriptor vector */
1170 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
1171         void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
1172 
1173 /* copy a NULL-terminated vector of descriptors */
1174 struct usb_descriptor_header **usb_copy_descriptors(
1175                 struct usb_descriptor_header **);
1176 
1177 /**
1178  * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
1179  * @v: vector of descriptors
1180  */
1181 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
1182 {
1183         kfree(v);
1184 }
1185 
1186 struct usb_function;
1187 int usb_assign_descriptors(struct usb_function *f,
1188                 struct usb_descriptor_header **fs,
1189                 struct usb_descriptor_header **hs,
1190                 struct usb_descriptor_header **ss);
1191 void usb_free_all_descriptors(struct usb_function *f);
1192 
1193 struct usb_descriptor_header *usb_otg_descriptor_alloc(
1194                                 struct usb_gadget *gadget);
1195 int usb_otg_descriptor_init(struct usb_gadget *gadget,
1196                 struct usb_descriptor_header *otg_desc);
1197 /*-------------------------------------------------------------------------*/
1198 
1199 /* utility to simplify map/unmap of usb_requests to/from DMA */
1200 
1201 extern int usb_gadget_map_request(struct usb_gadget *gadget,
1202                 struct usb_request *req, int is_in);
1203 
1204 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
1205                 struct usb_request *req, int is_in);
1206 
1207 /*-------------------------------------------------------------------------*/
1208 
1209 /* utility to set gadget state properly */
1210 
1211 extern void usb_gadget_set_state(struct usb_gadget *gadget,
1212                 enum usb_device_state state);
1213 
1214 /*-------------------------------------------------------------------------*/
1215 
1216 /* utility to tell udc core that the bus reset occurs */
1217 extern void usb_gadget_udc_reset(struct usb_gadget *gadget,
1218                 struct usb_gadget_driver *driver);
1219 
1220 /*-------------------------------------------------------------------------*/
1221 
1222 /* utility to give requests back to the gadget layer */
1223 
1224 extern void usb_gadget_giveback_request(struct usb_ep *ep,
1225                 struct usb_request *req);
1226 
1227 /*-------------------------------------------------------------------------*/
1228 
1229 /* utility to find endpoint by name */
1230 
1231 extern struct usb_ep *gadget_find_ep_by_name(struct usb_gadget *g,
1232                 const char *name);
1233 
1234 /*-------------------------------------------------------------------------*/
1235 
1236 /* utility to check if endpoint caps match descriptor needs */
1237 
1238 extern int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
1239                 struct usb_ep *ep, struct usb_endpoint_descriptor *desc,
1240                 struct usb_ss_ep_comp_descriptor *ep_comp);
1241 
1242 /*-------------------------------------------------------------------------*/
1243 
1244 /* utility to update vbus status for udc core, it may be scheduled */
1245 extern void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status);
1246 
1247 /*-------------------------------------------------------------------------*/
1248 
1249 /* utility wrapping a simple endpoint selection policy */
1250 
1251 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
1252                         struct usb_endpoint_descriptor *);
1253 
1254 
1255 extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
1256                         struct usb_endpoint_descriptor *,
1257                         struct usb_ss_ep_comp_descriptor *);
1258 
1259 extern void usb_ep_autoconfig_release(struct usb_ep *);
1260 
1261 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
1262 
1263 #endif /* __LINUX_USB_GADGET_H */
1264 

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