]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - include/linux/usb_gadget.h
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.
9 * (C) Copyright 2002-2004 by David Brownell
10 * All Rights Reserved.
12 * This software is licensed under the GNU GPL version 2.
15 #ifndef __LINUX_USB_GADGET_H
16 #define __LINUX_USB_GADGET_H
23 * struct usb_request - describes one i/o request
24 * @buf: Buffer used for data. Always provide this; some controllers
25 * only use PIO, or don't use DMA for some endpoints.
26 * @dma: DMA address corresponding to 'buf'. If you don't set this
27 * field, and the usb controller needs one, it is responsible
28 * for mapping and unmapping the buffer.
29 * @length: Length of that data
30 * @no_interrupt: If true, hints that no completion irq is needed.
31 * Helpful sometimes with deep request queues that are handled
32 * directly by DMA controllers.
33 * @zero: If true, when writing data, makes the last packet be "short"
34 * by adding a zero length packet as needed;
35 * @short_not_ok: When reading data, makes short packets be
36 * treated as errors (queue stops advancing till cleanup).
37 * @complete: Function called when request completes, so this request and
38 * its buffer may be re-used.
39 * Reads terminate with a short packet, or when the buffer fills,
40 * whichever comes first. When writes terminate, some data bytes
41 * will usually still be in flight (often in a hardware fifo).
42 * Errors (for reads or writes) stop the queue from advancing
43 * until the completion function returns, so that any transfers
44 * invalidated by the error may first be dequeued.
45 * @context: For use by the completion callback
46 * @list: For use by the gadget driver.
47 * @status: Reports completion code, zero or a negative errno.
48 * Normally, faults block the transfer queue from advancing until
49 * the completion callback returns.
50 * Code "-ESHUTDOWN" indicates completion caused by device disconnect,
51 * or when the driver disabled the endpoint.
52 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT
53 * transfers) this may be less than the requested length. If the
54 * short_not_ok flag is set, short reads are treated as errors
55 * even when status otherwise indicates successful completion.
56 * Note that for writes (IN transfers) some data bytes may still
57 * reside in a device-side FIFO when the request is reported as
60 * These are allocated/freed through the endpoint they're used with. The
61 * hardware's driver can add extra per-request data to the memory it returns,
62 * which often avoids separate memory allocations (potential failures),
63 * later when the request is queued.
65 * Request flags affect request handling, such as whether a zero length
66 * packet is written (the "zero" flag), whether a short read should be
67 * treated as an error (blocking request queue advance, the "short_not_ok"
68 * flag), or hinting that an interrupt is not required (the "no_interrupt"
69 * flag, for use with deep request queues).
71 * Bulk endpoints can use any size buffers, and can also be used for interrupt
72 * transfers. interrupt-only endpoints can be much less functional.
74 // NOTE this is analagous to 'struct urb' on the host side,
75 // except that it's thinner and promotes more pre-allocation.
82 unsigned no_interrupt
:1;
84 unsigned short_not_ok
:1;
86 void (*complete
)(struct usb_ep
*ep
,
87 struct usb_request
*req
);
89 struct list_head list
;
95 /*-------------------------------------------------------------------------*/
97 /* endpoint-specific parts of the api to the usb controller hardware.
98 * unlike the urb model, (de)multiplexing layers are not required.
99 * (so this api could slash overhead if used on the host side...)
101 * note that device side usb controllers commonly differ in how many
102 * endpoints they support, as well as their capabilities.
105 int (*enable
) (struct usb_ep
*ep
,
106 const struct usb_endpoint_descriptor
*desc
);
107 int (*disable
) (struct usb_ep
*ep
);
109 struct usb_request
*(*alloc_request
) (struct usb_ep
*ep
,
111 void (*free_request
) (struct usb_ep
*ep
, struct usb_request
*req
);
113 void *(*alloc_buffer
) (struct usb_ep
*ep
, unsigned bytes
,
114 dma_addr_t
*dma
, gfp_t gfp_flags
);
115 void (*free_buffer
) (struct usb_ep
*ep
, void *buf
, dma_addr_t dma
,
117 // NOTE: on 2.6, drivers may also use dma_map() and
118 // dma_sync_single_*() to directly manage dma overhead.
120 int (*queue
) (struct usb_ep
*ep
, struct usb_request
*req
,
122 int (*dequeue
) (struct usb_ep
*ep
, struct usb_request
*req
);
124 int (*set_halt
) (struct usb_ep
*ep
, int value
);
125 int (*fifo_status
) (struct usb_ep
*ep
);
126 void (*fifo_flush
) (struct usb_ep
*ep
);
130 * struct usb_ep - device side representation of USB endpoint
131 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
132 * @ops: Function pointers used to access hardware-specific operations.
133 * @ep_list:the gadget's ep_list holds all of its endpoints
134 * @maxpacket:The maximum packet size used on this endpoint. The initial
135 * value can sometimes be reduced (hardware allowing), according to
136 * the endpoint descriptor used to configure the endpoint.
137 * @driver_data:for use by the gadget driver. all other fields are
138 * read-only to gadget drivers.
140 * the bus controller driver lists all the general purpose endpoints in
141 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
142 * and is accessed only in response to a driver setup() callback.
148 const struct usb_ep_ops
*ops
;
149 struct list_head ep_list
;
150 unsigned maxpacket
:16;
153 /*-------------------------------------------------------------------------*/
156 * usb_ep_enable - configure endpoint, making it usable
157 * @ep:the endpoint being configured. may not be the endpoint named "ep0".
158 * drivers discover endpoints through the ep_list of a usb_gadget.
159 * @desc:descriptor for desired behavior. caller guarantees this pointer
160 * remains valid until the endpoint is disabled; the data byte order
161 * is little-endian (usb-standard).
163 * when configurations are set, or when interface settings change, the driver
164 * will enable or disable the relevant endpoints. while it is enabled, an
165 * endpoint may be used for i/o until the driver receives a disconnect() from
166 * the host or until the endpoint is disabled.
168 * the ep0 implementation (which calls this routine) must ensure that the
169 * hardware capabilities of each endpoint match the descriptor provided
170 * for it. for example, an endpoint named "ep2in-bulk" would be usable
171 * for interrupt transfers as well as bulk, but it likely couldn't be used
172 * for iso transfers or for endpoint 14. some endpoints are fully
173 * configurable, with more generic names like "ep-a". (remember that for
174 * USB, "in" means "towards the USB master".)
176 * returns zero, or a negative error code.
179 usb_ep_enable (struct usb_ep
*ep
, const struct usb_endpoint_descriptor
*desc
)
181 return ep
->ops
->enable (ep
, desc
);
185 * usb_ep_disable - endpoint is no longer usable
186 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
188 * no other task may be using this endpoint when this is called.
189 * any pending and uncompleted requests will complete with status
190 * indicating disconnect (-ESHUTDOWN) before this call returns.
191 * gadget drivers must call usb_ep_enable() again before queueing
192 * requests to the endpoint.
194 * returns zero, or a negative error code.
197 usb_ep_disable (struct usb_ep
*ep
)
199 return ep
->ops
->disable (ep
);
203 * usb_ep_alloc_request - allocate a request object to use with this endpoint
204 * @ep:the endpoint to be used with with the request
205 * @gfp_flags:GFP_* flags to use
207 * Request objects must be allocated with this call, since they normally
208 * need controller-specific setup and may even need endpoint-specific
209 * resources such as allocation of DMA descriptors.
210 * Requests may be submitted with usb_ep_queue(), and receive a single
211 * completion callback. Free requests with usb_ep_free_request(), when
212 * they are no longer needed.
214 * Returns the request, or null if one could not be allocated.
216 static inline struct usb_request
*
217 usb_ep_alloc_request (struct usb_ep
*ep
, gfp_t gfp_flags
)
219 return ep
->ops
->alloc_request (ep
, gfp_flags
);
223 * usb_ep_free_request - frees a request object
224 * @ep:the endpoint associated with the request
225 * @req:the request being freed
227 * Reverses the effect of usb_ep_alloc_request().
228 * Caller guarantees the request is not queued, and that it will
229 * no longer be requeued (or otherwise used).
232 usb_ep_free_request (struct usb_ep
*ep
, struct usb_request
*req
)
234 ep
->ops
->free_request (ep
, req
);
238 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
239 * @ep:the endpoint associated with the request
240 * @req:the request being submitted
241 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
242 * pre-allocate all necessary memory with the request.
244 * This tells the device controller to perform the specified request through
245 * that endpoint (reading or writing a buffer). When the request completes,
246 * including being canceled by usb_ep_dequeue(), the request's completion
247 * routine is called to return the request to the driver. Any endpoint
248 * (except control endpoints like ep0) may have more than one transfer
249 * request queued; they complete in FIFO order. Once a gadget driver
250 * submits a request, that request may not be examined or modified until it
251 * is given back to that driver through the completion callback.
253 * Each request is turned into one or more packets. The controller driver
254 * never merges adjacent requests into the same packet. OUT transfers
255 * will sometimes use data that's already buffered in the hardware.
256 * Drivers can rely on the fact that the first byte of the request's buffer
257 * always corresponds to the first byte of some USB packet, for both
258 * IN and OUT transfers.
260 * Bulk endpoints can queue any amount of data; the transfer is packetized
261 * automatically. The last packet will be short if the request doesn't fill it
262 * out completely. Zero length packets (ZLPs) should be avoided in portable
263 * protocols since not all usb hardware can successfully handle zero length
264 * packets. (ZLPs may be explicitly written, and may be implicitly written if
265 * the request 'zero' flag is set.) Bulk endpoints may also be used
266 * for interrupt transfers; but the reverse is not true, and some endpoints
267 * won't support every interrupt transfer. (Such as 768 byte packets.)
269 * Interrupt-only endpoints are less functional than bulk endpoints, for
270 * example by not supporting queueing or not handling buffers that are
271 * larger than the endpoint's maxpacket size. They may also treat data
272 * toggle differently.
274 * Control endpoints ... after getting a setup() callback, the driver queues
275 * one response (even if it would be zero length). That enables the
276 * status ack, after transfering data as specified in the response. Setup
277 * functions may return negative error codes to generate protocol stalls.
278 * (Note that some USB device controllers disallow protocol stall responses
279 * in some cases.) When control responses are deferred (the response is
280 * written after the setup callback returns), then usb_ep_set_halt() may be
281 * used on ep0 to trigger protocol stalls.
283 * For periodic endpoints, like interrupt or isochronous ones, the usb host
284 * arranges to poll once per interval, and the gadget driver usually will
285 * have queued some data to transfer at that time.
287 * Returns zero, or a negative error code. Endpoints that are not enabled
288 * report errors; errors will also be
289 * reported when the usb peripheral is disconnected.
292 usb_ep_queue (struct usb_ep
*ep
, struct usb_request
*req
, gfp_t gfp_flags
)
294 return ep
->ops
->queue (ep
, req
, gfp_flags
);
298 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
299 * @ep:the endpoint associated with the request
300 * @req:the request being canceled
302 * if the request is still active on the endpoint, it is dequeued and its
303 * completion routine is called (with status -ECONNRESET); else a negative
304 * error code is returned.
306 * note that some hardware can't clear out write fifos (to unlink the request
307 * at the head of the queue) except as part of disconnecting from usb. such
308 * restrictions prevent drivers from supporting configuration changes,
309 * even to configuration zero (a "chapter 9" requirement).
311 static inline int usb_ep_dequeue (struct usb_ep
*ep
, struct usb_request
*req
)
313 return ep
->ops
->dequeue (ep
, req
);
317 * usb_ep_set_halt - sets the endpoint halt feature.
318 * @ep: the non-isochronous endpoint being stalled
320 * Use this to stall an endpoint, perhaps as an error report.
321 * Except for control endpoints,
322 * the endpoint stays halted (will not stream any data) until the host
323 * clears this feature; drivers may need to empty the endpoint's request
324 * queue first, to make sure no inappropriate transfers happen.
326 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
327 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
328 * current altsetting, see usb_ep_clear_halt(). When switching altsettings,
329 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
331 * Returns zero, or a negative error code. On success, this call sets
332 * underlying hardware state that blocks data transfers.
333 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
334 * transfer requests are still queued, or if the controller hardware
335 * (usually a FIFO) still holds bytes that the host hasn't collected.
338 usb_ep_set_halt (struct usb_ep
*ep
)
340 return ep
->ops
->set_halt (ep
, 1);
344 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
345 * @ep:the bulk or interrupt endpoint being reset
347 * Use this when responding to the standard usb "set interface" request,
348 * for endpoints that aren't reconfigured, after clearing any other state
349 * in the endpoint's i/o queue.
351 * Returns zero, or a negative error code. On success, this call clears
352 * the underlying hardware state reflecting endpoint halt and data toggle.
353 * Note that some hardware can't support this request (like pxa2xx_udc),
354 * and accordingly can't correctly implement interface altsettings.
357 usb_ep_clear_halt (struct usb_ep
*ep
)
359 return ep
->ops
->set_halt (ep
, 0);
363 * usb_ep_fifo_status - returns number of bytes in fifo, or error
364 * @ep: the endpoint whose fifo status is being checked.
366 * FIFO endpoints may have "unclaimed data" in them in certain cases,
367 * such as after aborted transfers. Hosts may not have collected all
368 * the IN data written by the gadget driver (and reported by a request
369 * completion). The gadget driver may not have collected all the data
370 * written OUT to it by the host. Drivers that need precise handling for
371 * fault reporting or recovery may need to use this call.
373 * This returns the number of such bytes in the fifo, or a negative
374 * errno if the endpoint doesn't use a FIFO or doesn't support such
378 usb_ep_fifo_status (struct usb_ep
*ep
)
380 if (ep
->ops
->fifo_status
)
381 return ep
->ops
->fifo_status (ep
);
387 * usb_ep_fifo_flush - flushes contents of a fifo
388 * @ep: the endpoint whose fifo is being flushed.
390 * This call may be used to flush the "unclaimed data" that may exist in
391 * an endpoint fifo after abnormal transaction terminations. The call
392 * must never be used except when endpoint is not being used for any
393 * protocol translation.
396 usb_ep_fifo_flush (struct usb_ep
*ep
)
398 if (ep
->ops
->fifo_flush
)
399 ep
->ops
->fifo_flush (ep
);
403 /*-------------------------------------------------------------------------*/
407 /* the rest of the api to the controller hardware: device operations,
408 * which don't involve endpoints (or i/o).
410 struct usb_gadget_ops
{
411 int (*get_frame
)(struct usb_gadget
*);
412 int (*wakeup
)(struct usb_gadget
*);
413 int (*set_selfpowered
) (struct usb_gadget
*, int is_selfpowered
);
414 int (*vbus_session
) (struct usb_gadget
*, int is_active
);
415 int (*vbus_draw
) (struct usb_gadget
*, unsigned mA
);
416 int (*pullup
) (struct usb_gadget
*, int is_on
);
417 int (*ioctl
)(struct usb_gadget
*,
418 unsigned code
, unsigned long param
);
422 * struct usb_gadget - represents a usb slave device
423 * @ops: Function pointers used to access hardware-specific operations.
424 * @ep0: Endpoint zero, used when reading or writing responses to
425 * driver setup() requests
426 * @ep_list: List of other endpoints supported by the device.
427 * @speed: Speed of current connection to USB host.
428 * @is_dualspeed: True if the controller supports both high and full speed
429 * operation. If it does, the gadget driver must also support both.
430 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
431 * gadget driver must provide a USB OTG descriptor.
432 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
433 * is in the Mini-AB jack, and HNP has been used to switch roles
434 * so that the "A" device currently acts as A-Peripheral, not A-Host.
435 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
436 * supports HNP at this port.
437 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
438 * only supports HNP on a different root port.
439 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
440 * enabled HNP support.
441 * @name: Identifies the controller hardware type. Used in diagnostics
442 * and sometimes configuration.
443 * @dev: Driver model state for this abstract device.
445 * Gadgets have a mostly-portable "gadget driver" implementing device
446 * functions, handling all usb configurations and interfaces. Gadget
447 * drivers talk to hardware-specific code indirectly, through ops vectors.
448 * That insulates the gadget driver from hardware details, and packages
449 * the hardware endpoints through generic i/o queues. The "usb_gadget"
450 * and "usb_ep" interfaces provide that insulation from the hardware.
452 * Except for the driver data, all fields in this structure are
453 * read-only to the gadget driver. That driver data is part of the
454 * "driver model" infrastructure in 2.6 (and later) kernels, and for
455 * earlier systems is grouped in a similar structure that's not known
456 * to the rest of the kernel.
458 * Values of the three OTG device feature flags are updated before the
459 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
460 * driver suspend() calls. They are valid only when is_otg, and when the
461 * device is acting as a B-Peripheral (so is_a_peripheral is false).
464 /* readonly to gadget driver */
465 const struct usb_gadget_ops
*ops
;
467 struct list_head ep_list
; /* of usb_ep */
468 enum usb_device_speed speed
;
469 unsigned is_dualspeed
:1;
471 unsigned is_a_peripheral
:1;
472 unsigned b_hnp_enable
:1;
473 unsigned a_hnp_support
:1;
474 unsigned a_alt_hnp_support
:1;
479 static inline void set_gadget_data (struct usb_gadget
*gadget
, void *data
)
480 { dev_set_drvdata (&gadget
->dev
, data
); }
481 static inline void *get_gadget_data (struct usb_gadget
*gadget
)
482 { return dev_get_drvdata (&gadget
->dev
); }
484 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
485 #define gadget_for_each_ep(tmp,gadget) \
486 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
490 * usb_gadget_frame_number - returns the current frame number
491 * @gadget: controller that reports the frame number
493 * Returns the usb frame number, normally eleven bits from a SOF packet,
494 * or negative errno if this device doesn't support this capability.
496 static inline int usb_gadget_frame_number (struct usb_gadget
*gadget
)
498 return gadget
->ops
->get_frame (gadget
);
502 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
503 * @gadget: controller used to wake up the host
505 * Returns zero on success, else negative error code if the hardware
506 * doesn't support such attempts, or its support has not been enabled
507 * by the usb host. Drivers must return device descriptors that report
508 * their ability to support this, or hosts won't enable it.
510 * This may also try to use SRP to wake the host and start enumeration,
511 * even if OTG isn't otherwise in use. OTG devices may also start
512 * remote wakeup even when hosts don't explicitly enable it.
514 static inline int usb_gadget_wakeup (struct usb_gadget
*gadget
)
516 if (!gadget
->ops
->wakeup
)
518 return gadget
->ops
->wakeup (gadget
);
522 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
523 * @gadget:the device being declared as self-powered
525 * this affects the device status reported by the hardware driver
526 * to reflect that it now has a local power supply.
528 * returns zero on success, else negative errno.
531 usb_gadget_set_selfpowered (struct usb_gadget
*gadget
)
533 if (!gadget
->ops
->set_selfpowered
)
535 return gadget
->ops
->set_selfpowered (gadget
, 1);
539 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
540 * @gadget:the device being declared as bus-powered
542 * this affects the device status reported by the hardware driver.
543 * some hardware may not support bus-powered operation, in which
544 * case this feature's value can never change.
546 * returns zero on success, else negative errno.
549 usb_gadget_clear_selfpowered (struct usb_gadget
*gadget
)
551 if (!gadget
->ops
->set_selfpowered
)
553 return gadget
->ops
->set_selfpowered (gadget
, 0);
557 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
558 * @gadget:The device which now has VBUS power.
560 * This call is used by a driver for an external transceiver (or GPIO)
561 * that detects a VBUS power session starting. Common responses include
562 * resuming the controller, activating the D+ (or D-) pullup to let the
563 * host detect that a USB device is attached, and starting to draw power
564 * (8mA or possibly more, especially after SET_CONFIGURATION).
566 * Returns zero on success, else negative errno.
569 usb_gadget_vbus_connect(struct usb_gadget
*gadget
)
571 if (!gadget
->ops
->vbus_session
)
573 return gadget
->ops
->vbus_session (gadget
, 1);
577 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
578 * @gadget:The device whose VBUS usage is being described
579 * @mA:How much current to draw, in milliAmperes. This should be twice
580 * the value listed in the configuration descriptor bMaxPower field.
582 * This call is used by gadget drivers during SET_CONFIGURATION calls,
583 * reporting how much power the device may consume. For example, this
584 * could affect how quickly batteries are recharged.
586 * Returns zero on success, else negative errno.
589 usb_gadget_vbus_draw(struct usb_gadget
*gadget
, unsigned mA
)
591 if (!gadget
->ops
->vbus_draw
)
593 return gadget
->ops
->vbus_draw (gadget
, mA
);
597 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
598 * @gadget:the device whose VBUS supply is being described
600 * This call is used by a driver for an external transceiver (or GPIO)
601 * that detects a VBUS power session ending. Common responses include
602 * reversing everything done in usb_gadget_vbus_connect().
604 * Returns zero on success, else negative errno.
607 usb_gadget_vbus_disconnect(struct usb_gadget
*gadget
)
609 if (!gadget
->ops
->vbus_session
)
611 return gadget
->ops
->vbus_session (gadget
, 0);
615 * usb_gadget_connect - software-controlled connect to USB host
616 * @gadget:the peripheral being connected
618 * Enables the D+ (or potentially D-) pullup. The host will start
619 * enumerating this gadget when the pullup is active and a VBUS session
620 * is active (the link is powered). This pullup is always enabled unless
621 * usb_gadget_disconnect() has been used to disable it.
623 * Returns zero on success, else negative errno.
626 usb_gadget_connect (struct usb_gadget
*gadget
)
628 if (!gadget
->ops
->pullup
)
630 return gadget
->ops
->pullup (gadget
, 1);
634 * usb_gadget_disconnect - software-controlled disconnect from USB host
635 * @gadget:the peripheral being disconnected
637 * Disables the D+ (or potentially D-) pullup, which the host may see
638 * as a disconnect (when a VBUS session is active). Not all systems
639 * support software pullup controls.
641 * This routine may be used during the gadget driver bind() call to prevent
642 * the peripheral from ever being visible to the USB host, unless later
643 * usb_gadget_connect() is called. For example, user mode components may
644 * need to be activated before the system can talk to hosts.
646 * Returns zero on success, else negative errno.
649 usb_gadget_disconnect (struct usb_gadget
*gadget
)
651 if (!gadget
->ops
->pullup
)
653 return gadget
->ops
->pullup (gadget
, 0);
658 /*-------------------------------------------------------------------------*/
661 * struct usb_gadget_driver - driver for usb 'slave' devices
662 * @function: String describing the gadget's function
663 * @speed: Highest speed the driver handles.
664 * @bind: Invoked when the driver is bound to a gadget, usually
665 * after registering the driver.
666 * At that point, ep0 is fully initialized, and ep_list holds
667 * the currently-available endpoints.
668 * Called in a context that permits sleeping.
669 * @setup: Invoked for ep0 control requests that aren't handled by
670 * the hardware level driver. Most calls must be handled by
671 * the gadget driver, including descriptor and configuration
672 * management. The 16 bit members of the setup data are in
673 * USB byte order. Called in_interrupt; this may not sleep. Driver
674 * queues a response to ep0, or returns negative to stall.
675 * @disconnect: Invoked after all transfers have been stopped,
676 * when the host is disconnected. May be called in_interrupt; this
677 * may not sleep. Some devices can't detect disconnect, so this might
678 * not be called except as part of controller shutdown.
679 * @unbind: Invoked when the driver is unbound from a gadget,
680 * usually from rmmod (after a disconnect is reported).
681 * Called in a context that permits sleeping.
682 * @suspend: Invoked on USB suspend. May be called in_interrupt.
683 * @resume: Invoked on USB resume. May be called in_interrupt.
684 * @driver: Driver model state for this driver.
686 * Devices are disabled till a gadget driver successfully bind()s, which
687 * means the driver will handle setup() requests needed to enumerate (and
688 * meet "chapter 9" requirements) then do some useful work.
690 * If gadget->is_otg is true, the gadget driver must provide an OTG
691 * descriptor during enumeration, or else fail the bind() call. In such
692 * cases, no USB traffic may flow until both bind() returns without
693 * having called usb_gadget_disconnect(), and the USB host stack has
696 * Drivers use hardware-specific knowledge to configure the usb hardware.
697 * endpoint addressing is only one of several hardware characteristics that
698 * are in descriptors the ep0 implementation returns from setup() calls.
700 * Except for ep0 implementation, most driver code shouldn't need change to
701 * run on top of different usb controllers. It'll use endpoints set up by
702 * that ep0 implementation.
704 * The usb controller driver handles a few standard usb requests. Those
705 * include set_address, and feature flags for devices, interfaces, and
706 * endpoints (the get_status, set_feature, and clear_feature requests).
708 * Accordingly, the driver's setup() callback must always implement all
709 * get_descriptor requests, returning at least a device descriptor and
710 * a configuration descriptor. Drivers must make sure the endpoint
711 * descriptors match any hardware constraints. Some hardware also constrains
712 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
714 * The driver's setup() callback must also implement set_configuration,
715 * and should also implement set_interface, get_configuration, and
716 * get_interface. Setting a configuration (or interface) is where
717 * endpoints should be activated or (config 0) shut down.
719 * (Note that only the default control endpoint is supported. Neither
720 * hosts nor devices generally support control traffic except to ep0.)
722 * Most devices will ignore USB suspend/resume operations, and so will
723 * not provide those callbacks. However, some may need to change modes
724 * when the host is not longer directing those activities. For example,
725 * local controls (buttons, dials, etc) may need to be re-enabled since
726 * the (remote) host can't do that any longer; or an error state might
727 * be cleared, to make the device behave identically whether or not
728 * power is maintained.
730 struct usb_gadget_driver
{
732 enum usb_device_speed speed
;
733 int (*bind
)(struct usb_gadget
*);
734 void (*unbind
)(struct usb_gadget
*);
735 int (*setup
)(struct usb_gadget
*,
736 const struct usb_ctrlrequest
*);
737 void (*disconnect
)(struct usb_gadget
*);
738 void (*suspend
)(struct usb_gadget
*);
739 void (*resume
)(struct usb_gadget
*);
741 // FIXME support safe rmmod
742 struct device_driver driver
;
747 /*-------------------------------------------------------------------------*/
749 /* driver modules register and unregister, as usual.
750 * these calls must be made in a context that can sleep.
752 * these will usually be implemented directly by the hardware-dependent
753 * usb bus interface driver, which will only support a single driver.
757 * usb_gadget_register_driver - register a gadget driver
758 * @driver:the driver being registered
760 * Call this in your gadget driver's module initialization function,
761 * to tell the underlying usb controller driver about your driver.
762 * The driver's bind() function will be called to bind it to a
763 * gadget before this registration call returns. It's expected that
764 * the bind() functions will be in init sections.
765 * This function must be called in a context that can sleep.
767 int usb_gadget_register_driver (struct usb_gadget_driver
*driver
);
770 * usb_gadget_unregister_driver - unregister a gadget driver
771 * @driver:the driver being unregistered
773 * Call this in your gadget driver's module cleanup function,
774 * to tell the underlying usb controller that your driver is
775 * going away. If the controller is connected to a USB host,
776 * it will first disconnect(). The driver is also requested
777 * to unbind() and clean up any device state, before this procedure
778 * finally returns. It's expected that the unbind() functions
779 * will in in exit sections, so may not be linked in some kernels.
780 * This function must be called in a context that can sleep.
782 int usb_gadget_unregister_driver (struct usb_gadget_driver
*driver
);
784 /*-------------------------------------------------------------------------*/
786 /* utility to simplify dealing with string descriptors */
789 * struct usb_string - wraps a C string and its USB id
790 * @id:the (nonzero) ID for this string
791 * @s:the string, in UTF-8 encoding
793 * If you're using usb_gadget_get_string(), use this to wrap a string
794 * together with its ID.
802 * struct usb_gadget_strings - a set of USB strings in a given language
803 * @language:identifies the strings' language (0x0409 for en-us)
804 * @strings:array of strings with their ids
806 * If you're using usb_gadget_get_string(), use this to wrap all the
807 * strings for a given language.
809 struct usb_gadget_strings
{
810 u16 language
; /* 0x0409 for en-us */
811 struct usb_string
*strings
;
814 /* put descriptor for string with that id into buf (buflen >= 256) */
815 int usb_gadget_get_string (struct usb_gadget_strings
*table
, int id
, u8
*buf
);
817 /*-------------------------------------------------------------------------*/
819 /* utility to simplify managing config descriptors */
821 /* write vector of descriptors into buffer */
822 int usb_descriptor_fillbuf(void *, unsigned,
823 const struct usb_descriptor_header
**);
825 /* build config descriptor from single descriptor vector */
826 int usb_gadget_config_buf(const struct usb_config_descriptor
*config
,
827 void *buf
, unsigned buflen
, const struct usb_descriptor_header
**desc
);
829 /*-------------------------------------------------------------------------*/
831 /* utility wrapping a simple endpoint selection policy */
833 extern struct usb_ep
*usb_ep_autoconfig (struct usb_gadget
*,
834 struct usb_endpoint_descriptor
*) __devinit
;
836 extern void usb_ep_autoconfig_reset (struct usb_gadget
*) __devinit
;
838 #endif /* __KERNEL__ */
840 #endif /* __LINUX_USB_GADGET_H */