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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 - device side representation of USB endpoint
145  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
146  * @ops: Function pointers used to access hardware-specific operations.
147  * @ep_list:the gadget's ep_list holds all of its endpoints
148  * @maxpacket:The maximum packet size used on this endpoint.  The initial
149  *      value can sometimes be reduced (hardware allowing), according to
150  *      the endpoint descriptor used to configure the endpoint.
151  * @maxpacket_limit:The maximum packet size value which can be handled by this
152  *      endpoint. It's set once by UDC driver when endpoint is initialized, and
153  *      should not be changed. Should not be confused with maxpacket.
154  * @max_streams: The maximum number of streams supported
155  *      by this EP (0 - 16, actual number is 2^n)
156  * @mult: multiplier, 'mult' value for SS Isoc EPs
157  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
158  * @driver_data:for use by the gadget driver.
159  * @address: used to identify the endpoint when finding descriptor that
160  *      matches connection speed
161  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
162  *      enabled and remains valid until the endpoint is disabled.
163  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
164  *      descriptor that is used to configure the endpoint
165  *
166  * the bus controller driver lists all the general purpose endpoints in
167  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
168  * and is accessed only in response to a driver setup() callback.
169  */
170 struct usb_ep {
171         void                    *driver_data;
172 
173         const char              *name;
174         const struct usb_ep_ops *ops;
175         struct list_head        ep_list;
176         unsigned                maxpacket:16;
177         unsigned                maxpacket_limit:16;
178         unsigned                max_streams:16;
179         unsigned                mult:2;
180         unsigned                maxburst:5;
181         u8                      address;
182         const struct usb_endpoint_descriptor    *desc;
183         const struct usb_ss_ep_comp_descriptor  *comp_desc;
184 };
185 
186 /*-------------------------------------------------------------------------*/
187 
188 /**
189  * usb_ep_set_maxpacket_limit - set maximum packet size limit for endpoint
190  * @ep:the endpoint being configured
191  * @maxpacket_limit:value of maximum packet size limit
192  *
193  * This function shoud be used only in UDC drivers to initialize endpoint
194  * (usually in probe function).
195  */
196 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
197                                               unsigned maxpacket_limit)
198 {
199         ep->maxpacket_limit = maxpacket_limit;
200         ep->maxpacket = maxpacket_limit;
201 }
202 
203 /**
204  * usb_ep_enable - configure endpoint, making it usable
205  * @ep:the endpoint being configured.  may not be the endpoint named "ep0".
206  *      drivers discover endpoints through the ep_list of a usb_gadget.
207  *
208  * When configurations are set, or when interface settings change, the driver
209  * will enable or disable the relevant endpoints.  while it is enabled, an
210  * endpoint may be used for i/o until the driver receives a disconnect() from
211  * the host or until the endpoint is disabled.
212  *
213  * the ep0 implementation (which calls this routine) must ensure that the
214  * hardware capabilities of each endpoint match the descriptor provided
215  * for it.  for example, an endpoint named "ep2in-bulk" would be usable
216  * for interrupt transfers as well as bulk, but it likely couldn't be used
217  * for iso transfers or for endpoint 14.  some endpoints are fully
218  * configurable, with more generic names like "ep-a".  (remember that for
219  * USB, "in" means "towards the USB master".)
220  *
221  * returns zero, or a negative error code.
222  */
223 static inline int usb_ep_enable(struct usb_ep *ep)
224 {
225         return ep->ops->enable(ep, ep->desc);
226 }
227 
228 /**
229  * usb_ep_disable - endpoint is no longer usable
230  * @ep:the endpoint being unconfigured.  may not be the endpoint named "ep0".
231  *
232  * no other task may be using this endpoint when this is called.
233  * any pending and uncompleted requests will complete with status
234  * indicating disconnect (-ESHUTDOWN) before this call returns.
235  * gadget drivers must call usb_ep_enable() again before queueing
236  * requests to the endpoint.
237  *
238  * returns zero, or a negative error code.
239  */
240 static inline int usb_ep_disable(struct usb_ep *ep)
241 {
242         return ep->ops->disable(ep);
243 }
244 
245 /**
246  * usb_ep_alloc_request - allocate a request object to use with this endpoint
247  * @ep:the endpoint to be used with with the request
248  * @gfp_flags:GFP_* flags to use
249  *
250  * Request objects must be allocated with this call, since they normally
251  * need controller-specific setup and may even need endpoint-specific
252  * resources such as allocation of DMA descriptors.
253  * Requests may be submitted with usb_ep_queue(), and receive a single
254  * completion callback.  Free requests with usb_ep_free_request(), when
255  * they are no longer needed.
256  *
257  * Returns the request, or null if one could not be allocated.
258  */
259 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
260                                                        gfp_t gfp_flags)
261 {
262         return ep->ops->alloc_request(ep, gfp_flags);
263 }
264 
265 /**
266  * usb_ep_free_request - frees a request object
267  * @ep:the endpoint associated with the request
268  * @req:the request being freed
269  *
270  * Reverses the effect of usb_ep_alloc_request().
271  * Caller guarantees the request is not queued, and that it will
272  * no longer be requeued (or otherwise used).
273  */
274 static inline void usb_ep_free_request(struct usb_ep *ep,
275                                        struct usb_request *req)
276 {
277         ep->ops->free_request(ep, req);
278 }
279 
280 /**
281  * usb_ep_queue - queues (submits) an I/O request to an endpoint.
282  * @ep:the endpoint associated with the request
283  * @req:the request being submitted
284  * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
285  *      pre-allocate all necessary memory with the request.
286  *
287  * This tells the device controller to perform the specified request through
288  * that endpoint (reading or writing a buffer).  When the request completes,
289  * including being canceled by usb_ep_dequeue(), the request's completion
290  * routine is called to return the request to the driver.  Any endpoint
291  * (except control endpoints like ep0) may have more than one transfer
292  * request queued; they complete in FIFO order.  Once a gadget driver
293  * submits a request, that request may not be examined or modified until it
294  * is given back to that driver through the completion callback.
295  *
296  * Each request is turned into one or more packets.  The controller driver
297  * never merges adjacent requests into the same packet.  OUT transfers
298  * will sometimes use data that's already buffered in the hardware.
299  * Drivers can rely on the fact that the first byte of the request's buffer
300  * always corresponds to the first byte of some USB packet, for both
301  * IN and OUT transfers.
302  *
303  * Bulk endpoints can queue any amount of data; the transfer is packetized
304  * automatically.  The last packet will be short if the request doesn't fill it
305  * out completely.  Zero length packets (ZLPs) should be avoided in portable
306  * protocols since not all usb hardware can successfully handle zero length
307  * packets.  (ZLPs may be explicitly written, and may be implicitly written if
308  * the request 'zero' flag is set.)  Bulk endpoints may also be used
309  * for interrupt transfers; but the reverse is not true, and some endpoints
310  * won't support every interrupt transfer.  (Such as 768 byte packets.)
311  *
312  * Interrupt-only endpoints are less functional than bulk endpoints, for
313  * example by not supporting queueing or not handling buffers that are
314  * larger than the endpoint's maxpacket size.  They may also treat data
315  * toggle differently.
316  *
317  * Control endpoints ... after getting a setup() callback, the driver queues
318  * one response (even if it would be zero length).  That enables the
319  * status ack, after transferring data as specified in the response.  Setup
320  * functions may return negative error codes to generate protocol stalls.
321  * (Note that some USB device controllers disallow protocol stall responses
322  * in some cases.)  When control responses are deferred (the response is
323  * written after the setup callback returns), then usb_ep_set_halt() may be
324  * used on ep0 to trigger protocol stalls.  Depending on the controller,
325  * it may not be possible to trigger a status-stage protocol stall when the
326  * data stage is over, that is, from within the response's completion
327  * routine.
328  *
329  * For periodic endpoints, like interrupt or isochronous ones, the usb host
330  * arranges to poll once per interval, and the gadget driver usually will
331  * have queued some data to transfer at that time.
332  *
333  * Returns zero, or a negative error code.  Endpoints that are not enabled
334  * report errors; errors will also be
335  * reported when the usb peripheral is disconnected.
336  */
337 static inline int usb_ep_queue(struct usb_ep *ep,
338                                struct usb_request *req, gfp_t gfp_flags)
339 {
340         return ep->ops->queue(ep, req, gfp_flags);
341 }
342 
343 /**
344  * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
345  * @ep:the endpoint associated with the request
346  * @req:the request being canceled
347  *
348  * If the request is still active on the endpoint, it is dequeued and its
349  * completion routine is called (with status -ECONNRESET); else a negative
350  * error code is returned. This is guaranteed to happen before the call to
351  * usb_ep_dequeue() returns.
352  *
353  * Note that some hardware can't clear out write fifos (to unlink the request
354  * at the head of the queue) except as part of disconnecting from usb. Such
355  * restrictions prevent drivers from supporting configuration changes,
356  * even to configuration zero (a "chapter 9" requirement).
357  */
358 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
359 {
360         return ep->ops->dequeue(ep, req);
361 }
362 
363 /**
364  * usb_ep_set_halt - sets the endpoint halt feature.
365  * @ep: the non-isochronous endpoint being stalled
366  *
367  * Use this to stall an endpoint, perhaps as an error report.
368  * Except for control endpoints,
369  * the endpoint stays halted (will not stream any data) until the host
370  * clears this feature; drivers may need to empty the endpoint's request
371  * queue first, to make sure no inappropriate transfers happen.
372  *
373  * Note that while an endpoint CLEAR_FEATURE will be invisible to the
374  * gadget driver, a SET_INTERFACE will not be.  To reset endpoints for the
375  * current altsetting, see usb_ep_clear_halt().  When switching altsettings,
376  * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
377  *
378  * Returns zero, or a negative error code.  On success, this call sets
379  * underlying hardware state that blocks data transfers.
380  * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
381  * transfer requests are still queued, or if the controller hardware
382  * (usually a FIFO) still holds bytes that the host hasn't collected.
383  */
384 static inline int usb_ep_set_halt(struct usb_ep *ep)
385 {
386         return ep->ops->set_halt(ep, 1);
387 }
388 
389 /**
390  * usb_ep_clear_halt - clears endpoint halt, and resets toggle
391  * @ep:the bulk or interrupt endpoint being reset
392  *
393  * Use this when responding to the standard usb "set interface" request,
394  * for endpoints that aren't reconfigured, after clearing any other state
395  * in the endpoint's i/o queue.
396  *
397  * Returns zero, or a negative error code.  On success, this call clears
398  * the underlying hardware state reflecting endpoint halt and data toggle.
399  * Note that some hardware can't support this request (like pxa2xx_udc),
400  * and accordingly can't correctly implement interface altsettings.
401  */
402 static inline int usb_ep_clear_halt(struct usb_ep *ep)
403 {
404         return ep->ops->set_halt(ep, 0);
405 }
406 
407 /**
408  * usb_ep_set_wedge - sets the halt feature and ignores clear requests
409  * @ep: the endpoint being wedged
410  *
411  * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
412  * requests. If the gadget driver clears the halt status, it will
413  * automatically unwedge the endpoint.
414  *
415  * Returns zero on success, else negative errno.
416  */
417 static inline int
418 usb_ep_set_wedge(struct usb_ep *ep)
419 {
420         if (ep->ops->set_wedge)
421                 return ep->ops->set_wedge(ep);
422         else
423                 return ep->ops->set_halt(ep, 1);
424 }
425 
426 /**
427  * usb_ep_fifo_status - returns number of bytes in fifo, or error
428  * @ep: the endpoint whose fifo status is being checked.
429  *
430  * FIFO endpoints may have "unclaimed data" in them in certain cases,
431  * such as after aborted transfers.  Hosts may not have collected all
432  * the IN data written by the gadget driver (and reported by a request
433  * completion).  The gadget driver may not have collected all the data
434  * written OUT to it by the host.  Drivers that need precise handling for
435  * fault reporting or recovery may need to use this call.
436  *
437  * This returns the number of such bytes in the fifo, or a negative
438  * errno if the endpoint doesn't use a FIFO or doesn't support such
439  * precise handling.
440  */
441 static inline int usb_ep_fifo_status(struct usb_ep *ep)
442 {
443         if (ep->ops->fifo_status)
444                 return ep->ops->fifo_status(ep);
445         else
446                 return -EOPNOTSUPP;
447 }
448 
449 /**
450  * usb_ep_fifo_flush - flushes contents of a fifo
451  * @ep: the endpoint whose fifo is being flushed.
452  *
453  * This call may be used to flush the "unclaimed data" that may exist in
454  * an endpoint fifo after abnormal transaction terminations.  The call
455  * must never be used except when endpoint is not being used for any
456  * protocol translation.
457  */
458 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
459 {
460         if (ep->ops->fifo_flush)
461                 ep->ops->fifo_flush(ep);
462 }
463 
464 
465 /*-------------------------------------------------------------------------*/
466 
467 struct usb_dcd_config_params {
468         __u8  bU1devExitLat;    /* U1 Device exit Latency */
469 #define USB_DEFAULT_U1_DEV_EXIT_LAT     0x01    /* Less then 1 microsec */
470         __le16 bU2DevExitLat;   /* U2 Device exit Latency */
471 #define USB_DEFAULT_U2_DEV_EXIT_LAT     0x1F4   /* Less then 500 microsec */
472 };
473 
474 
475 struct usb_gadget;
476 struct usb_gadget_driver;
477 
478 /* the rest of the api to the controller hardware: device operations,
479  * which don't involve endpoints (or i/o).
480  */
481 struct usb_gadget_ops {
482         int     (*get_frame)(struct usb_gadget *);
483         int     (*wakeup)(struct usb_gadget *);
484         int     (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
485         int     (*vbus_session) (struct usb_gadget *, int is_active);
486         int     (*vbus_draw) (struct usb_gadget *, unsigned mA);
487         int     (*pullup) (struct usb_gadget *, int is_on);
488         int     (*ioctl)(struct usb_gadget *,
489                                 unsigned code, unsigned long param);
490         void    (*get_config_params)(struct usb_dcd_config_params *);
491         int     (*udc_start)(struct usb_gadget *,
492                         struct usb_gadget_driver *);
493         int     (*udc_stop)(struct usb_gadget *,
494                         struct usb_gadget_driver *);
495 };
496 
497 /**
498  * struct usb_gadget - represents a usb slave device
499  * @work: (internal use) Workqueue to be used for sysfs_notify()
500  * @ops: Function pointers used to access hardware-specific operations.
501  * @ep0: Endpoint zero, used when reading or writing responses to
502  *      driver setup() requests
503  * @ep_list: List of other endpoints supported by the device.
504  * @speed: Speed of current connection to USB host.
505  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
506  *      and all slower speeds.
507  * @state: the state we are now (attached, suspended, configured, etc)
508  * @name: Identifies the controller hardware type.  Used in diagnostics
509  *      and sometimes configuration.
510  * @dev: Driver model state for this abstract device.
511  * @out_epnum: last used out ep number
512  * @in_epnum: last used in ep number
513  * @sg_supported: true if we can handle scatter-gather
514  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
515  *      gadget driver must provide a USB OTG descriptor.
516  * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
517  *      is in the Mini-AB jack, and HNP has been used to switch roles
518  *      so that the "A" device currently acts as A-Peripheral, not A-Host.
519  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
520  *      supports HNP at this port.
521  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
522  *      only supports HNP on a different root port.
523  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
524  *      enabled HNP support.
525  * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
526  *      MaxPacketSize.
527  *
528  * Gadgets have a mostly-portable "gadget driver" implementing device
529  * functions, handling all usb configurations and interfaces.  Gadget
530  * drivers talk to hardware-specific code indirectly, through ops vectors.
531  * That insulates the gadget driver from hardware details, and packages
532  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
533  * and "usb_ep" interfaces provide that insulation from the hardware.
534  *
535  * Except for the driver data, all fields in this structure are
536  * read-only to the gadget driver.  That driver data is part of the
537  * "driver model" infrastructure in 2.6 (and later) kernels, and for
538  * earlier systems is grouped in a similar structure that's not known
539  * to the rest of the kernel.
540  *
541  * Values of the three OTG device feature flags are updated before the
542  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
543  * driver suspend() calls.  They are valid only when is_otg, and when the
544  * device is acting as a B-Peripheral (so is_a_peripheral is false).
545  */
546 struct usb_gadget {
547         struct work_struct              work;
548         /* readonly to gadget driver */
549         const struct usb_gadget_ops     *ops;
550         struct usb_ep                   *ep0;
551         struct list_head                ep_list;        /* of usb_ep */
552         enum usb_device_speed           speed;
553         enum usb_device_speed           max_speed;
554         enum usb_device_state           state;
555         const char                      *name;
556         struct device                   dev;
557         unsigned                        out_epnum;
558         unsigned                        in_epnum;
559 
560         unsigned                        sg_supported:1;
561         unsigned                        is_otg:1;
562         unsigned                        is_a_peripheral:1;
563         unsigned                        b_hnp_enable:1;
564         unsigned                        a_hnp_support:1;
565         unsigned                        a_alt_hnp_support:1;
566         unsigned                        quirk_ep_out_aligned_size:1;
567 };
568 #define work_to_gadget(w)       (container_of((w), struct usb_gadget, work))
569 
570 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
571         { dev_set_drvdata(&gadget->dev, data); }
572 static inline void *get_gadget_data(struct usb_gadget *gadget)
573         { return dev_get_drvdata(&gadget->dev); }
574 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
575 {
576         return container_of(dev, struct usb_gadget, dev);
577 }
578 
579 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
580 #define gadget_for_each_ep(tmp, gadget) \
581         list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
582 
583 
584 /**
585  * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
586  *      requires quirk_ep_out_aligned_size, otherwise reguens len.
587  * @g: controller to check for quirk
588  * @ep: the endpoint whose maxpacketsize is used to align @len
589  * @len: buffer size's length to align to @ep's maxpacketsize
590  *
591  * This helper is used in case it's required for any reason to check and maybe
592  * align buffer's size to an ep's maxpacketsize.
593  */
594 static inline size_t
595 usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
596 {
597         return !g->quirk_ep_out_aligned_size ? len :
598                         round_up(len, (size_t)ep->desc->wMaxPacketSize);
599 }
600 
601 /**
602  * gadget_is_dualspeed - return true iff the hardware handles high speed
603  * @g: controller that might support both high and full speeds
604  */
605 static inline int gadget_is_dualspeed(struct usb_gadget *g)
606 {
607         return g->max_speed >= USB_SPEED_HIGH;
608 }
609 
610 /**
611  * gadget_is_superspeed() - return true if the hardware handles superspeed
612  * @g: controller that might support superspeed
613  */
614 static inline int gadget_is_superspeed(struct usb_gadget *g)
615 {
616         return g->max_speed >= USB_SPEED_SUPER;
617 }
618 
619 /**
620  * gadget_is_otg - return true iff the hardware is OTG-ready
621  * @g: controller that might have a Mini-AB connector
622  *
623  * This is a runtime test, since kernels with a USB-OTG stack sometimes
624  * run on boards which only have a Mini-B (or Mini-A) connector.
625  */
626 static inline int gadget_is_otg(struct usb_gadget *g)
627 {
628 #ifdef CONFIG_USB_OTG
629         return g->is_otg;
630 #else
631         return 0;
632 #endif
633 }
634 
635 /**
636  * usb_gadget_frame_number - returns the current frame number
637  * @gadget: controller that reports the frame number
638  *
639  * Returns the usb frame number, normally eleven bits from a SOF packet,
640  * or negative errno if this device doesn't support this capability.
641  */
642 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
643 {
644         return gadget->ops->get_frame(gadget);
645 }
646 
647 /**
648  * usb_gadget_wakeup - tries to wake up the host connected to this gadget
649  * @gadget: controller used to wake up the host
650  *
651  * Returns zero on success, else negative error code if the hardware
652  * doesn't support such attempts, or its support has not been enabled
653  * by the usb host.  Drivers must return device descriptors that report
654  * their ability to support this, or hosts won't enable it.
655  *
656  * This may also try to use SRP to wake the host and start enumeration,
657  * even if OTG isn't otherwise in use.  OTG devices may also start
658  * remote wakeup even when hosts don't explicitly enable it.
659  */
660 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
661 {
662         if (!gadget->ops->wakeup)
663                 return -EOPNOTSUPP;
664         return gadget->ops->wakeup(gadget);
665 }
666 
667 /**
668  * usb_gadget_set_selfpowered - sets the device selfpowered feature.
669  * @gadget:the device being declared as self-powered
670  *
671  * this affects the device status reported by the hardware driver
672  * to reflect that it now has a local power supply.
673  *
674  * returns zero on success, else negative errno.
675  */
676 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
677 {
678         if (!gadget->ops->set_selfpowered)
679                 return -EOPNOTSUPP;
680         return gadget->ops->set_selfpowered(gadget, 1);
681 }
682 
683 /**
684  * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
685  * @gadget:the device being declared as bus-powered
686  *
687  * this affects the device status reported by the hardware driver.
688  * some hardware may not support bus-powered operation, in which
689  * case this feature's value can never change.
690  *
691  * returns zero on success, else negative errno.
692  */
693 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
694 {
695         if (!gadget->ops->set_selfpowered)
696                 return -EOPNOTSUPP;
697         return gadget->ops->set_selfpowered(gadget, 0);
698 }
699 
700 /**
701  * usb_gadget_vbus_connect - Notify controller that VBUS is powered
702  * @gadget:The device which now has VBUS power.
703  * Context: can sleep
704  *
705  * This call is used by a driver for an external transceiver (or GPIO)
706  * that detects a VBUS power session starting.  Common responses include
707  * resuming the controller, activating the D+ (or D-) pullup to let the
708  * host detect that a USB device is attached, and starting to draw power
709  * (8mA or possibly more, especially after SET_CONFIGURATION).
710  *
711  * Returns zero on success, else negative errno.
712  */
713 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
714 {
715         if (!gadget->ops->vbus_session)
716                 return -EOPNOTSUPP;
717         return gadget->ops->vbus_session(gadget, 1);
718 }
719 
720 /**
721  * usb_gadget_vbus_draw - constrain controller's VBUS power usage
722  * @gadget:The device whose VBUS usage is being described
723  * @mA:How much current to draw, in milliAmperes.  This should be twice
724  *      the value listed in the configuration descriptor bMaxPower field.
725  *
726  * This call is used by gadget drivers during SET_CONFIGURATION calls,
727  * reporting how much power the device may consume.  For example, this
728  * could affect how quickly batteries are recharged.
729  *
730  * Returns zero on success, else negative errno.
731  */
732 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
733 {
734         if (!gadget->ops->vbus_draw)
735                 return -EOPNOTSUPP;
736         return gadget->ops->vbus_draw(gadget, mA);
737 }
738 
739 /**
740  * usb_gadget_vbus_disconnect - notify controller about VBUS session end
741  * @gadget:the device whose VBUS supply is being described
742  * Context: can sleep
743  *
744  * This call is used by a driver for an external transceiver (or GPIO)
745  * that detects a VBUS power session ending.  Common responses include
746  * reversing everything done in usb_gadget_vbus_connect().
747  *
748  * Returns zero on success, else negative errno.
749  */
750 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
751 {
752         if (!gadget->ops->vbus_session)
753                 return -EOPNOTSUPP;
754         return gadget->ops->vbus_session(gadget, 0);
755 }
756 
757 /**
758  * usb_gadget_connect - software-controlled connect to USB host
759  * @gadget:the peripheral being connected
760  *
761  * Enables the D+ (or potentially D-) pullup.  The host will start
762  * enumerating this gadget when the pullup is active and a VBUS session
763  * is active (the link is powered).  This pullup is always enabled unless
764  * usb_gadget_disconnect() has been used to disable it.
765  *
766  * Returns zero on success, else negative errno.
767  */
768 static inline int usb_gadget_connect(struct usb_gadget *gadget)
769 {
770         if (!gadget->ops->pullup)
771                 return -EOPNOTSUPP;
772         return gadget->ops->pullup(gadget, 1);
773 }
774 
775 /**
776  * usb_gadget_disconnect - software-controlled disconnect from USB host
777  * @gadget:the peripheral being disconnected
778  *
779  * Disables the D+ (or potentially D-) pullup, which the host may see
780  * as a disconnect (when a VBUS session is active).  Not all systems
781  * support software pullup controls.
782  *
783  * This routine may be used during the gadget driver bind() call to prevent
784  * the peripheral from ever being visible to the USB host, unless later
785  * usb_gadget_connect() is called.  For example, user mode components may
786  * need to be activated before the system can talk to hosts.
787  *
788  * Returns zero on success, else negative errno.
789  */
790 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
791 {
792         if (!gadget->ops->pullup)
793                 return -EOPNOTSUPP;
794         return gadget->ops->pullup(gadget, 0);
795 }
796 
797 
798 /*-------------------------------------------------------------------------*/
799 
800 /**
801  * struct usb_gadget_driver - driver for usb 'slave' devices
802  * @function: String describing the gadget's function
803  * @max_speed: Highest speed the driver handles.
804  * @setup: Invoked for ep0 control requests that aren't handled by
805  *      the hardware level driver. Most calls must be handled by
806  *      the gadget driver, including descriptor and configuration
807  *      management.  The 16 bit members of the setup data are in
808  *      USB byte order. Called in_interrupt; this may not sleep.  Driver
809  *      queues a response to ep0, or returns negative to stall.
810  * @disconnect: Invoked after all transfers have been stopped,
811  *      when the host is disconnected.  May be called in_interrupt; this
812  *      may not sleep.  Some devices can't detect disconnect, so this might
813  *      not be called except as part of controller shutdown.
814  * @bind: the driver's bind callback
815  * @unbind: Invoked when the driver is unbound from a gadget,
816  *      usually from rmmod (after a disconnect is reported).
817  *      Called in a context that permits sleeping.
818  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
819  * @resume: Invoked on USB resume.  May be called in_interrupt.
820  * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
821  *      and should be called in_interrupt.
822  * @driver: Driver model state for this driver.
823  *
824  * Devices are disabled till a gadget driver successfully bind()s, which
825  * means the driver will handle setup() requests needed to enumerate (and
826  * meet "chapter 9" requirements) then do some useful work.
827  *
828  * If gadget->is_otg is true, the gadget driver must provide an OTG
829  * descriptor during enumeration, or else fail the bind() call.  In such
830  * cases, no USB traffic may flow until both bind() returns without
831  * having called usb_gadget_disconnect(), and the USB host stack has
832  * initialized.
833  *
834  * Drivers use hardware-specific knowledge to configure the usb hardware.
835  * endpoint addressing is only one of several hardware characteristics that
836  * are in descriptors the ep0 implementation returns from setup() calls.
837  *
838  * Except for ep0 implementation, most driver code shouldn't need change to
839  * run on top of different usb controllers.  It'll use endpoints set up by
840  * that ep0 implementation.
841  *
842  * The usb controller driver handles a few standard usb requests.  Those
843  * include set_address, and feature flags for devices, interfaces, and
844  * endpoints (the get_status, set_feature, and clear_feature requests).
845  *
846  * Accordingly, the driver's setup() callback must always implement all
847  * get_descriptor requests, returning at least a device descriptor and
848  * a configuration descriptor.  Drivers must make sure the endpoint
849  * descriptors match any hardware constraints. Some hardware also constrains
850  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
851  *
852  * The driver's setup() callback must also implement set_configuration,
853  * and should also implement set_interface, get_configuration, and
854  * get_interface.  Setting a configuration (or interface) is where
855  * endpoints should be activated or (config 0) shut down.
856  *
857  * (Note that only the default control endpoint is supported.  Neither
858  * hosts nor devices generally support control traffic except to ep0.)
859  *
860  * Most devices will ignore USB suspend/resume operations, and so will
861  * not provide those callbacks.  However, some may need to change modes
862  * when the host is not longer directing those activities.  For example,
863  * local controls (buttons, dials, etc) may need to be re-enabled since
864  * the (remote) host can't do that any longer; or an error state might
865  * be cleared, to make the device behave identically whether or not
866  * power is maintained.
867  */
868 struct usb_gadget_driver {
869         char                    *function;
870         enum usb_device_speed   max_speed;
871         int                     (*bind)(struct usb_gadget *gadget,
872                                         struct usb_gadget_driver *driver);
873         void                    (*unbind)(struct usb_gadget *);
874         int                     (*setup)(struct usb_gadget *,
875                                         const struct usb_ctrlrequest *);
876         void                    (*disconnect)(struct usb_gadget *);
877         void                    (*suspend)(struct usb_gadget *);
878         void                    (*resume)(struct usb_gadget *);
879         void                    (*reset)(struct usb_gadget *);
880 
881         /* FIXME support safe rmmod */
882         struct device_driver    driver;
883 };
884 
885 
886 
887 /*-------------------------------------------------------------------------*/
888 
889 /* driver modules register and unregister, as usual.
890  * these calls must be made in a context that can sleep.
891  *
892  * these will usually be implemented directly by the hardware-dependent
893  * usb bus interface driver, which will only support a single driver.
894  */
895 
896 /**
897  * usb_gadget_probe_driver - probe a gadget driver
898  * @driver: the driver being registered
899  * Context: can sleep
900  *
901  * Call this in your gadget driver's module initialization function,
902  * to tell the underlying usb controller driver about your driver.
903  * The @bind() function will be called to bind it to a gadget before this
904  * registration call returns.  It's expected that the @bind() function will
905  * be in init sections.
906  */
907 int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
908 
909 /**
910  * usb_gadget_unregister_driver - unregister a gadget driver
911  * @driver:the driver being unregistered
912  * Context: can sleep
913  *
914  * Call this in your gadget driver's module cleanup function,
915  * to tell the underlying usb controller that your driver is
916  * going away.  If the controller is connected to a USB host,
917  * it will first disconnect().  The driver is also requested
918  * to unbind() and clean up any device state, before this procedure
919  * finally returns.  It's expected that the unbind() functions
920  * will in in exit sections, so may not be linked in some kernels.
921  */
922 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
923 
924 extern int usb_add_gadget_udc_release(struct device *parent,
925                 struct usb_gadget *gadget, void (*release)(struct device *dev));
926 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
927 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
928 extern int udc_attach_driver(const char *name,
929                 struct usb_gadget_driver *driver);
930 
931 /*-------------------------------------------------------------------------*/
932 
933 /* utility to simplify dealing with string descriptors */
934 
935 /**
936  * struct usb_string - wraps a C string and its USB id
937  * @id:the (nonzero) ID for this string
938  * @s:the string, in UTF-8 encoding
939  *
940  * If you're using usb_gadget_get_string(), use this to wrap a string
941  * together with its ID.
942  */
943 struct usb_string {
944         u8                      id;
945         const char              *s;
946 };
947 
948 /**
949  * struct usb_gadget_strings - a set of USB strings in a given language
950  * @language:identifies the strings' language (0x0409 for en-us)
951  * @strings:array of strings with their ids
952  *
953  * If you're using usb_gadget_get_string(), use this to wrap all the
954  * strings for a given language.
955  */
956 struct usb_gadget_strings {
957         u16                     language;       /* 0x0409 for en-us */
958         struct usb_string       *strings;
959 };
960 
961 struct usb_gadget_string_container {
962         struct list_head        list;
963         u8                      *stash[0];
964 };
965 
966 /* put descriptor for string with that id into buf (buflen >= 256) */
967 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
968 
969 /*-------------------------------------------------------------------------*/
970 
971 /* utility to simplify managing config descriptors */
972 
973 /* write vector of descriptors into buffer */
974 int usb_descriptor_fillbuf(void *, unsigned,
975                 const struct usb_descriptor_header **);
976 
977 /* build config descriptor from single descriptor vector */
978 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
979         void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
980 
981 /* copy a NULL-terminated vector of descriptors */
982 struct usb_descriptor_header **usb_copy_descriptors(
983                 struct usb_descriptor_header **);
984 
985 /**
986  * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
987  * @v: vector of descriptors
988  */
989 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
990 {
991         kfree(v);
992 }
993 
994 struct usb_function;
995 int usb_assign_descriptors(struct usb_function *f,
996                 struct usb_descriptor_header **fs,
997                 struct usb_descriptor_header **hs,
998                 struct usb_descriptor_header **ss);
999 void usb_free_all_descriptors(struct usb_function *f);
1000 
1001 /*-------------------------------------------------------------------------*/
1002 
1003 /* utility to simplify map/unmap of usb_requests to/from DMA */
1004 
1005 extern int usb_gadget_map_request(struct usb_gadget *gadget,
1006                 struct usb_request *req, int is_in);
1007 
1008 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
1009                 struct usb_request *req, int is_in);
1010 
1011 /*-------------------------------------------------------------------------*/
1012 
1013 /* utility to set gadget state properly */
1014 
1015 extern void usb_gadget_set_state(struct usb_gadget *gadget,
1016                 enum usb_device_state state);
1017 
1018 /*-------------------------------------------------------------------------*/
1019 
1020 /* utility to tell udc core that the bus reset occurs */
1021 extern void usb_gadget_udc_reset(struct usb_gadget *gadget,
1022                 struct usb_gadget_driver *driver);
1023 
1024 /*-------------------------------------------------------------------------*/
1025 
1026 /* utility to give requests back to the gadget layer */
1027 
1028 extern void usb_gadget_giveback_request(struct usb_ep *ep,
1029                 struct usb_request *req);
1030 
1031 
1032 /*-------------------------------------------------------------------------*/
1033 
1034 /* utility wrapping a simple endpoint selection policy */
1035 
1036 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
1037                         struct usb_endpoint_descriptor *);
1038 
1039 
1040 extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
1041                         struct usb_endpoint_descriptor *,
1042                         struct usb_ss_ep_comp_descriptor *);
1043 
1044 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
1045 
1046 #endif /* __LINUX_USB_GADGET_H */
1047 

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