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
18 #include <linux/slab.h>
19 #include <linux/usb/ch9.h>
24 * struct usb_request - describes one i/o request
25 * @buf: Buffer used for data. Always provide this; some controllers
26 * only use PIO, or don't use DMA for some endpoints.
27 * @dma: DMA address corresponding to 'buf'. If you don't set this
28 * field, and the usb controller needs one, it is responsible
29 * for mapping and unmapping the buffer.
30 * @length: Length of that data
31 * @no_interrupt: If true, hints that no completion irq is needed.
32 * Helpful sometimes with deep request queues that are handled
33 * directly by DMA controllers.
34 * @zero: If true, when writing data, makes the last packet be "short"
35 * by adding a zero length packet as needed;
36 * @short_not_ok: When reading data, makes short packets be
37 * treated as errors (queue stops advancing till cleanup).
38 * @complete: Function called when request completes, so this request and
39 * its buffer may be re-used. The function will always be called with
40 * interrupts disabled, and it must not sleep.
41 * Reads terminate with a short packet, or when the buffer fills,
42 * whichever comes first. When writes terminate, some data bytes
43 * will usually still be in flight (often in a hardware fifo).
44 * Errors (for reads or writes) stop the queue from advancing
45 * until the completion function returns, so that any transfers
46 * invalidated by the error may first be dequeued.
47 * @context: For use by the completion callback
48 * @list: For use by the gadget driver.
49 * @status: Reports completion code, zero or a negative errno.
50 * Normally, faults block the transfer queue from advancing until
51 * the completion callback returns.
52 * Code "-ESHUTDOWN" indicates completion caused by device disconnect,
53 * or when the driver disabled the endpoint.
54 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT
55 * transfers) this may be less than the requested length. If the
56 * short_not_ok flag is set, short reads are treated as errors
57 * even when status otherwise indicates successful completion.
58 * Note that for writes (IN transfers) some data bytes may still
59 * reside in a device-side FIFO when the request is reported as
62 * These are allocated/freed through the endpoint they're used with. The
63 * hardware's driver can add extra per-request data to the memory it returns,
64 * which often avoids separate memory allocations (potential failures),
65 * later when the request is queued.
67 * Request flags affect request handling, such as whether a zero length
68 * packet is written (the "zero" flag), whether a short read should be
69 * treated as an error (blocking request queue advance, the "short_not_ok"
70 * flag), or hinting that an interrupt is not required (the "no_interrupt"
71 * flag, for use with deep request queues).
73 * Bulk endpoints can use any size buffers, and can also be used for interrupt
74 * transfers. interrupt-only endpoints can be much less functional.
76 * NOTE: this is analogous to 'struct urb' on the host side, except that
77 * it's thinner and promotes more pre-allocation.
85 unsigned no_interrupt:1;
87 unsigned short_not_ok:1;
89 void (*complete)(struct usb_ep *ep,
90 struct usb_request *req);
92 struct list_head list;
98 /*-------------------------------------------------------------------------*/
100 /* endpoint-specific parts of the api to the usb controller hardware.
101 * unlike the urb model, (de)multiplexing layers are not required.
102 * (so this api could slash overhead if used on the host side...)
104 * note that device side usb controllers commonly differ in how many
105 * endpoints they support, as well as their capabilities.
108 int (*enable) (struct usb_ep *ep,
109 const struct usb_endpoint_descriptor *desc);
110 int (*disable) (struct usb_ep *ep);
112 struct usb_request *(*alloc_request) (struct usb_ep *ep,
114 void (*free_request) (struct usb_ep *ep, struct usb_request *req);
116 int (*queue) (struct usb_ep *ep, struct usb_request *req,
118 int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
120 int (*set_halt) (struct usb_ep *ep, int value);
121 int (*set_wedge) (struct usb_ep *ep);
123 int (*fifo_status) (struct usb_ep *ep);
124 void (*fifo_flush) (struct usb_ep *ep);
128 * struct usb_ep - device side representation of USB endpoint
129 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
130 * @ops: Function pointers used to access hardware-specific operations.
131 * @ep_list:the gadget's ep_list holds all of its endpoints
132 * @maxpacket:The maximum packet size used on this endpoint. The initial
133 * value can sometimes be reduced (hardware allowing), according to
134 * the endpoint descriptor used to configure the endpoint.
135 * @driver_data:for use by the gadget driver.
136 * @address: used to identify the endpoint when finding descriptor that
137 * matches connection speed
138 * @desc: endpoint descriptor. This pointer is set before the endpoint is
139 * enabled and remains valid until the endpoint is disabled.
141 * the bus controller driver lists all the general purpose endpoints in
142 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
143 * and is accessed only in response to a driver setup() callback.
149 const struct usb_ep_ops *ops;
150 struct list_head ep_list;
151 unsigned maxpacket:16;
153 const struct usb_endpoint_descriptor *desc;
156 /*-------------------------------------------------------------------------*/
159 * usb_ep_enable - configure endpoint, making it usable
160 * @ep:the endpoint being configured. may not be the endpoint named "ep0".
161 * drivers discover endpoints through the ep_list of a usb_gadget.
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.
178 static inline int usb_ep_enable(struct usb_ep *ep)
180 return ep->ops->enable(ep, ep->desc);
184 * usb_ep_disable - endpoint is no longer usable
185 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
187 * no other task may be using this endpoint when this is called.
188 * any pending and uncompleted requests will complete with status
189 * indicating disconnect (-ESHUTDOWN) before this call returns.
190 * gadget drivers must call usb_ep_enable() again before queueing
191 * requests to the endpoint.
193 * returns zero, or a negative error code.
195 static inline int usb_ep_disable(struct usb_ep *ep)
197 return ep->ops->disable(ep);
201 * usb_ep_alloc_request - allocate a request object to use with this endpoint
202 * @ep:the endpoint to be used with with the request
203 * @gfp_flags:GFP_* flags to use
205 * Request objects must be allocated with this call, since they normally
206 * need controller-specific setup and may even need endpoint-specific
207 * resources such as allocation of DMA descriptors.
208 * Requests may be submitted with usb_ep_queue(), and receive a single
209 * completion callback. Free requests with usb_ep_free_request(), when
210 * they are no longer needed.
212 * Returns the request, or null if one could not be allocated.
214 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
217 return ep->ops->alloc_request(ep, gfp_flags);
221 * usb_ep_free_request - frees a request object
222 * @ep:the endpoint associated with the request
223 * @req:the request being freed
225 * Reverses the effect of usb_ep_alloc_request().
226 * Caller guarantees the request is not queued, and that it will
227 * no longer be requeued (or otherwise used).
229 static inline void usb_ep_free_request(struct usb_ep *ep,
230 struct usb_request *req)
232 ep->ops->free_request(ep, req);
236 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
237 * @ep:the endpoint associated with the request
238 * @req:the request being submitted
239 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
240 * pre-allocate all necessary memory with the request.
242 * This tells the device controller to perform the specified request through
243 * that endpoint (reading or writing a buffer). When the request completes,
244 * including being canceled by usb_ep_dequeue(), the request's completion
245 * routine is called to return the request to the driver. Any endpoint
246 * (except control endpoints like ep0) may have more than one transfer
247 * request queued; they complete in FIFO order. Once a gadget driver
248 * submits a request, that request may not be examined or modified until it
249 * is given back to that driver through the completion callback.
251 * Each request is turned into one or more packets. The controller driver
252 * never merges adjacent requests into the same packet. OUT transfers
253 * will sometimes use data that's already buffered in the hardware.
254 * Drivers can rely on the fact that the first byte of the request's buffer
255 * always corresponds to the first byte of some USB packet, for both
256 * IN and OUT transfers.
258 * Bulk endpoints can queue any amount of data; the transfer is packetized
259 * automatically. The last packet will be short if the request doesn't fill it
260 * out completely. Zero length packets (ZLPs) should be avoided in portable
261 * protocols since not all usb hardware can successfully handle zero length
262 * packets. (ZLPs may be explicitly written, and may be implicitly written if
263 * the request 'zero' flag is set.) Bulk endpoints may also be used
264 * for interrupt transfers; but the reverse is not true, and some endpoints
265 * won't support every interrupt transfer. (Such as 768 byte packets.)
267 * Interrupt-only endpoints are less functional than bulk endpoints, for
268 * example by not supporting queueing or not handling buffers that are
269 * larger than the endpoint's maxpacket size. They may also treat data
270 * toggle differently.
272 * Control endpoints ... after getting a setup() callback, the driver queues
273 * one response (even if it would be zero length). That enables the
274 * status ack, after transferring data as specified in the response. Setup
275 * functions may return negative error codes to generate protocol stalls.
276 * (Note that some USB device controllers disallow protocol stall responses
277 * in some cases.) When control responses are deferred (the response is
278 * written after the setup callback returns), then usb_ep_set_halt() may be
279 * used on ep0 to trigger protocol stalls. Depending on the controller,
280 * it may not be possible to trigger a status-stage protocol stall when the
281 * data stage is over, that is, from within the response's completion
284 * For periodic endpoints, like interrupt or isochronous ones, the usb host
285 * arranges to poll once per interval, and the gadget driver usually will
286 * have queued some data to transfer at that time.
288 * Returns zero, or a negative error code. Endpoints that are not enabled
289 * report errors; errors will also be
290 * reported when the usb peripheral is disconnected.
292 static inline int usb_ep_queue(struct usb_ep *ep,
293 struct usb_request *req, gfp_t gfp_flags)
295 return ep->ops->queue(ep, req, gfp_flags);
299 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
300 * @ep:the endpoint associated with the request
301 * @req:the request being canceled
303 * if the request is still active on the endpoint, it is dequeued and its
304 * completion routine is called (with status -ECONNRESET); else a negative
305 * error code is returned.
307 * note that some hardware can't clear out write fifos (to unlink the request
308 * at the head of the queue) except as part of disconnecting from usb. such
309 * restrictions prevent drivers from supporting configuration changes,
310 * even to configuration zero (a "chapter 9" requirement).
312 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
314 return ep->ops->dequeue(ep, req);
318 * usb_ep_set_halt - sets the endpoint halt feature.
319 * @ep: the non-isochronous endpoint being stalled
321 * Use this to stall an endpoint, perhaps as an error report.
322 * Except for control endpoints,
323 * the endpoint stays halted (will not stream any data) until the host
324 * clears this feature; drivers may need to empty the endpoint's request
325 * queue first, to make sure no inappropriate transfers happen.
327 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
328 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
329 * current altsetting, see usb_ep_clear_halt(). When switching altsettings,
330 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
332 * Returns zero, or a negative error code. On success, this call sets
333 * underlying hardware state that blocks data transfers.
334 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
335 * transfer requests are still queued, or if the controller hardware
336 * (usually a FIFO) still holds bytes that the host hasn't collected.
338 static inline int 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.
356 static inline int usb_ep_clear_halt(struct usb_ep *ep)
358 return ep->ops->set_halt(ep, 0);
362 * usb_ep_set_wedge - sets the halt feature and ignores clear requests
363 * @ep: the endpoint being wedged
365 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
366 * requests. If the gadget driver clears the halt status, it will
367 * automatically unwedge the endpoint.
369 * Returns zero on success, else negative errno.
372 usb_ep_set_wedge(struct usb_ep *ep)
374 if (ep->ops->set_wedge)
375 return ep->ops->set_wedge(ep);
377 return ep->ops->set_halt(ep, 1);
381 * usb_ep_fifo_status - returns number of bytes in fifo, or error
382 * @ep: the endpoint whose fifo status is being checked.
384 * FIFO endpoints may have "unclaimed data" in them in certain cases,
385 * such as after aborted transfers. Hosts may not have collected all
386 * the IN data written by the gadget driver (and reported by a request
387 * completion). The gadget driver may not have collected all the data
388 * written OUT to it by the host. Drivers that need precise handling for
389 * fault reporting or recovery may need to use this call.
391 * This returns the number of such bytes in the fifo, or a negative
392 * errno if the endpoint doesn't use a FIFO or doesn't support such
395 static inline int usb_ep_fifo_status(struct usb_ep *ep)
397 if (ep->ops->fifo_status)
398 return ep->ops->fifo_status(ep);
404 * usb_ep_fifo_flush - flushes contents of a fifo
405 * @ep: the endpoint whose fifo is being flushed.
407 * This call may be used to flush the "unclaimed data" that may exist in
408 * an endpoint fifo after abnormal transaction terminations. The call
409 * must never be used except when endpoint is not being used for any
410 * protocol translation.
412 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
414 if (ep->ops->fifo_flush)
415 ep->ops->fifo_flush(ep);
419 /*-------------------------------------------------------------------------*/
422 struct usb_gadget_driver;
424 /* the rest of the api to the controller hardware: device operations,
425 * which don't involve endpoints (or i/o).
427 struct usb_gadget_ops {
428 int (*get_frame)(struct usb_gadget *);
429 int (*wakeup)(struct usb_gadget *);
430 int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
431 int (*vbus_session) (struct usb_gadget *, int is_active);
432 int (*vbus_draw) (struct usb_gadget *, unsigned mA);
433 int (*pullup) (struct usb_gadget *, int is_on);
434 int (*ioctl)(struct usb_gadget *,
435 unsigned code, unsigned long param);
436 int (*start)(struct usb_gadget_driver *,
437 int (*bind)(struct usb_gadget *));
438 int (*stop)(struct usb_gadget_driver *);
442 * struct usb_gadget - represents a usb slave device
443 * @ops: Function pointers used to access hardware-specific operations.
444 * @ep0: Endpoint zero, used when reading or writing responses to
445 * driver setup() requests
446 * @ep_list: List of other endpoints supported by the device.
447 * @speed: Speed of current connection to USB host.
448 * @is_dualspeed: True if the controller supports both high and full speed
449 * operation. If it does, the gadget driver must also support both.
450 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
451 * gadget driver must provide a USB OTG descriptor.
452 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
453 * is in the Mini-AB jack, and HNP has been used to switch roles
454 * so that the "A" device currently acts as A-Peripheral, not A-Host.
455 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
456 * supports HNP at this port.
457 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
458 * only supports HNP on a different root port.
459 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
460 * enabled HNP support.
461 * @name: Identifies the controller hardware type. Used in diagnostics
462 * and sometimes configuration.
463 * @dev: Driver model state for this abstract device.
465 * Gadgets have a mostly-portable "gadget driver" implementing device
466 * functions, handling all usb configurations and interfaces. Gadget
467 * drivers talk to hardware-specific code indirectly, through ops vectors.
468 * That insulates the gadget driver from hardware details, and packages
469 * the hardware endpoints through generic i/o queues. The "usb_gadget"
470 * and "usb_ep" interfaces provide that insulation from the hardware.
472 * Except for the driver data, all fields in this structure are
473 * read-only to the gadget driver. That driver data is part of the
474 * "driver model" infrastructure in 2.6 (and later) kernels, and for
475 * earlier systems is grouped in a similar structure that's not known
476 * to the rest of the kernel.
478 * Values of the three OTG device feature flags are updated before the
479 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
480 * driver suspend() calls. They are valid only when is_otg, and when the
481 * device is acting as a B-Peripheral (so is_a_peripheral is false).
484 /* readonly to gadget driver */
485 const struct usb_gadget_ops *ops;
487 struct list_head ep_list; /* of usb_ep */
488 enum usb_device_speed speed;
489 unsigned is_dualspeed:1;
491 unsigned is_a_peripheral:1;
492 unsigned b_hnp_enable:1;
493 unsigned a_hnp_support:1;
494 unsigned a_alt_hnp_support:1;
499 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
500 { dev_set_drvdata(&gadget->dev, data); }
501 static inline void *get_gadget_data(struct usb_gadget *gadget)
502 { return dev_get_drvdata(&gadget->dev); }
503 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
505 return container_of(dev, struct usb_gadget, dev);
508 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
509 #define gadget_for_each_ep(tmp, gadget) \
510 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
514 * gadget_is_dualspeed - return true iff the hardware handles high speed
515 * @g: controller that might support both high and full speeds
517 static inline int gadget_is_dualspeed(struct usb_gadget *g)
519 #ifdef CONFIG_USB_GADGET_DUALSPEED
520 /* runtime test would check "g->is_dualspeed" ... that might be
521 * useful to work around hardware bugs, but is mostly pointless
530 * gadget_is_otg - return true iff the hardware is OTG-ready
531 * @g: controller that might have a Mini-AB connector
533 * This is a runtime test, since kernels with a USB-OTG stack sometimes
534 * run on boards which only have a Mini-B (or Mini-A) connector.
536 static inline int gadget_is_otg(struct usb_gadget *g)
538 #ifdef CONFIG_USB_OTG
546 * usb_gadget_frame_number - returns the current frame number
547 * @gadget: controller that reports the frame number
549 * Returns the usb frame number, normally eleven bits from a SOF packet,
550 * or negative errno if this device doesn't support this capability.
552 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
554 return gadget->ops->get_frame(gadget);
558 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
559 * @gadget: controller used to wake up the host
561 * Returns zero on success, else negative error code if the hardware
562 * doesn't support such attempts, or its support has not been enabled
563 * by the usb host. Drivers must return device descriptors that report
564 * their ability to support this, or hosts won't enable it.
566 * This may also try to use SRP to wake the host and start enumeration,
567 * even if OTG isn't otherwise in use. OTG devices may also start
568 * remote wakeup even when hosts don't explicitly enable it.
570 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
572 if (!gadget->ops->wakeup)
574 return gadget->ops->wakeup(gadget);
578 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
579 * @gadget:the device being declared as self-powered
581 * this affects the device status reported by the hardware driver
582 * to reflect that it now has a local power supply.
584 * returns zero on success, else negative errno.
586 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
588 if (!gadget->ops->set_selfpowered)
590 return gadget->ops->set_selfpowered(gadget, 1);
594 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
595 * @gadget:the device being declared as bus-powered
597 * this affects the device status reported by the hardware driver.
598 * some hardware may not support bus-powered operation, in which
599 * case this feature's value can never change.
601 * returns zero on success, else negative errno.
603 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
605 if (!gadget->ops->set_selfpowered)
607 return gadget->ops->set_selfpowered(gadget, 0);
611 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
612 * @gadget:The device which now has VBUS power.
615 * This call is used by a driver for an external transceiver (or GPIO)
616 * that detects a VBUS power session starting. Common responses include
617 * resuming the controller, activating the D+ (or D-) pullup to let the
618 * host detect that a USB device is attached, and starting to draw power
619 * (8mA or possibly more, especially after SET_CONFIGURATION).
621 * Returns zero on success, else negative errno.
623 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
625 if (!gadget->ops->vbus_session)
627 return gadget->ops->vbus_session(gadget, 1);
631 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
632 * @gadget:The device whose VBUS usage is being described
633 * @mA:How much current to draw, in milliAmperes. This should be twice
634 * the value listed in the configuration descriptor bMaxPower field.
636 * This call is used by gadget drivers during SET_CONFIGURATION calls,
637 * reporting how much power the device may consume. For example, this
638 * could affect how quickly batteries are recharged.
640 * Returns zero on success, else negative errno.
642 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
644 if (!gadget->ops->vbus_draw)
646 return gadget->ops->vbus_draw(gadget, mA);
650 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
651 * @gadget:the device whose VBUS supply is being described
654 * This call is used by a driver for an external transceiver (or GPIO)
655 * that detects a VBUS power session ending. Common responses include
656 * reversing everything done in usb_gadget_vbus_connect().
658 * Returns zero on success, else negative errno.
660 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
662 if (!gadget->ops->vbus_session)
664 return gadget->ops->vbus_session(gadget, 0);
668 * usb_gadget_connect - software-controlled connect to USB host
669 * @gadget:the peripheral being connected
671 * Enables the D+ (or potentially D-) pullup. The host will start
672 * enumerating this gadget when the pullup is active and a VBUS session
673 * is active (the link is powered). This pullup is always enabled unless
674 * usb_gadget_disconnect() has been used to disable it.
676 * Returns zero on success, else negative errno.
678 static inline int usb_gadget_connect(struct usb_gadget *gadget)
680 if (!gadget->ops->pullup)
682 return gadget->ops->pullup(gadget, 1);
686 * usb_gadget_disconnect - software-controlled disconnect from USB host
687 * @gadget:the peripheral being disconnected
689 * Disables the D+ (or potentially D-) pullup, which the host may see
690 * as a disconnect (when a VBUS session is active). Not all systems
691 * support software pullup controls.
693 * This routine may be used during the gadget driver bind() call to prevent
694 * the peripheral from ever being visible to the USB host, unless later
695 * usb_gadget_connect() is called. For example, user mode components may
696 * need to be activated before the system can talk to hosts.
698 * Returns zero on success, else negative errno.
700 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
702 if (!gadget->ops->pullup)
704 return gadget->ops->pullup(gadget, 0);
708 /*-------------------------------------------------------------------------*/
711 * struct usb_gadget_driver - driver for usb 'slave' devices
712 * @function: String describing the gadget's function
713 * @speed: Highest speed the driver handles.
714 * @setup: Invoked for ep0 control requests that aren't handled by
715 * the hardware level driver. Most calls must be handled by
716 * the gadget driver, including descriptor and configuration
717 * management. The 16 bit members of the setup data are in
718 * USB byte order. Called in_interrupt; this may not sleep. Driver
719 * queues a response to ep0, or returns negative to stall.
720 * @disconnect: Invoked after all transfers have been stopped,
721 * when the host is disconnected. May be called in_interrupt; this
722 * may not sleep. Some devices can't detect disconnect, so this might
723 * not be called except as part of controller shutdown.
724 * @unbind: Invoked when the driver is unbound from a gadget,
725 * usually from rmmod (after a disconnect is reported).
726 * Called in a context that permits sleeping.
727 * @suspend: Invoked on USB suspend. May be called in_interrupt.
728 * @resume: Invoked on USB resume. May be called in_interrupt.
729 * @driver: Driver model state for this driver.
731 * Devices are disabled till a gadget driver successfully bind()s, which
732 * means the driver will handle setup() requests needed to enumerate (and
733 * meet "chapter 9" requirements) then do some useful work.
735 * If gadget->is_otg is true, the gadget driver must provide an OTG
736 * descriptor during enumeration, or else fail the bind() call. In such
737 * cases, no USB traffic may flow until both bind() returns without
738 * having called usb_gadget_disconnect(), and the USB host stack has
741 * Drivers use hardware-specific knowledge to configure the usb hardware.
742 * endpoint addressing is only one of several hardware characteristics that
743 * are in descriptors the ep0 implementation returns from setup() calls.
745 * Except for ep0 implementation, most driver code shouldn't need change to
746 * run on top of different usb controllers. It'll use endpoints set up by
747 * that ep0 implementation.
749 * The usb controller driver handles a few standard usb requests. Those
750 * include set_address, and feature flags for devices, interfaces, and
751 * endpoints (the get_status, set_feature, and clear_feature requests).
753 * Accordingly, the driver's setup() callback must always implement all
754 * get_descriptor requests, returning at least a device descriptor and
755 * a configuration descriptor. Drivers must make sure the endpoint
756 * descriptors match any hardware constraints. Some hardware also constrains
757 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
759 * The driver's setup() callback must also implement set_configuration,
760 * and should also implement set_interface, get_configuration, and
761 * get_interface. Setting a configuration (or interface) is where
762 * endpoints should be activated or (config 0) shut down.
764 * (Note that only the default control endpoint is supported. Neither
765 * hosts nor devices generally support control traffic except to ep0.)
767 * Most devices will ignore USB suspend/resume operations, and so will
768 * not provide those callbacks. However, some may need to change modes
769 * when the host is not longer directing those activities. For example,
770 * local controls (buttons, dials, etc) may need to be re-enabled since
771 * the (remote) host can't do that any longer; or an error state might
772 * be cleared, to make the device behave identically whether or not
773 * power is maintained.
775 struct usb_gadget_driver {
777 enum usb_device_speed speed;
778 void (*unbind)(struct usb_gadget *);
779 int (*setup)(struct usb_gadget *,
780 const struct usb_ctrlrequest *);
781 void (*disconnect)(struct usb_gadget *);
782 void (*suspend)(struct usb_gadget *);
783 void (*resume)(struct usb_gadget *);
785 /* FIXME support safe rmmod */
786 struct device_driver driver;
791 /*-------------------------------------------------------------------------*/
793 /* driver modules register and unregister, as usual.
794 * these calls must be made in a context that can sleep.
796 * these will usually be implemented directly by the hardware-dependent
797 * usb bus interface driver, which will only support a single driver.
801 * usb_gadget_probe_driver - probe a gadget driver
802 * @driver: the driver being registered
803 * @bind: the driver's bind callback
806 * Call this in your gadget driver's module initialization function,
807 * to tell the underlying usb controller driver about your driver.
808 * The @bind() function will be called to bind it to a gadget before this
809 * registration call returns. It's expected that the @bind() function will
810 * be in init sections.
812 int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
813 int (*bind)(struct usb_gadget *));
816 * usb_gadget_unregister_driver - unregister a gadget driver
817 * @driver:the driver being unregistered
820 * Call this in your gadget driver's module cleanup function,
821 * to tell the underlying usb controller that your driver is
822 * going away. If the controller is connected to a USB host,
823 * it will first disconnect(). The driver is also requested
824 * to unbind() and clean up any device state, before this procedure
825 * finally returns. It's expected that the unbind() functions
826 * will in in exit sections, so may not be linked in some kernels.
828 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
830 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
831 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
833 /*-------------------------------------------------------------------------*/
835 /* utility to simplify dealing with string descriptors */
838 * struct usb_string - wraps a C string and its USB id
839 * @id:the (nonzero) ID for this string
840 * @s:the string, in UTF-8 encoding
842 * If you're using usb_gadget_get_string(), use this to wrap a string
843 * together with its ID.
851 * struct usb_gadget_strings - a set of USB strings in a given language
852 * @language:identifies the strings' language (0x0409 for en-us)
853 * @strings:array of strings with their ids
855 * If you're using usb_gadget_get_string(), use this to wrap all the
856 * strings for a given language.
858 struct usb_gadget_strings {
859 u16 language; /* 0x0409 for en-us */
860 struct usb_string *strings;
863 /* put descriptor for string with that id into buf (buflen >= 256) */
864 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
866 /*-------------------------------------------------------------------------*/
868 /* utility to simplify managing config descriptors */
870 /* write vector of descriptors into buffer */
871 int usb_descriptor_fillbuf(void *, unsigned,
872 const struct usb_descriptor_header **);
874 /* build config descriptor from single descriptor vector */
875 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
876 void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
878 /* copy a NULL-terminated vector of descriptors */
879 struct usb_descriptor_header **usb_copy_descriptors(
880 struct usb_descriptor_header **);
882 /* return copy of endpoint descriptor given original descriptor set */
883 struct usb_endpoint_descriptor *usb_find_endpoint(
884 struct usb_descriptor_header **src,
885 struct usb_descriptor_header **copy,
886 struct usb_endpoint_descriptor *match);
889 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
890 * @v: vector of descriptors
892 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
897 /*-------------------------------------------------------------------------*/
899 /* utility wrapping a simple endpoint selection policy */
901 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
902 struct usb_endpoint_descriptor *);
904 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
906 #endif /* __LINUX_USB_GADGET_H */