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>
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. The function will always be called with
39 * interrupts disabled, and it must not sleep.
40 * Reads terminate with a short packet, or when the buffer fills,
41 * whichever comes first. When writes terminate, some data bytes
42 * will usually still be in flight (often in a hardware fifo).
43 * Errors (for reads or writes) stop the queue from advancing
44 * until the completion function returns, so that any transfers
45 * invalidated by the error may first be dequeued.
46 * @context: For use by the completion callback
47 * @list: For use by the gadget driver.
48 * @status: Reports completion code, zero or a negative errno.
49 * Normally, faults block the transfer queue from advancing until
50 * the completion callback returns.
51 * Code "-ESHUTDOWN" indicates completion caused by device disconnect,
52 * or when the driver disabled the endpoint.
53 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT
54 * transfers) this may be less than the requested length. If the
55 * short_not_ok flag is set, short reads are treated as errors
56 * even when status otherwise indicates successful completion.
57 * Note that for writes (IN transfers) some data bytes may still
58 * reside in a device-side FIFO when the request is reported as
61 * These are allocated/freed through the endpoint they're used with. The
62 * hardware's driver can add extra per-request data to the memory it returns,
63 * which often avoids separate memory allocations (potential failures),
64 * later when the request is queued.
66 * Request flags affect request handling, such as whether a zero length
67 * packet is written (the "zero" flag), whether a short read should be
68 * treated as an error (blocking request queue advance, the "short_not_ok"
69 * flag), or hinting that an interrupt is not required (the "no_interrupt"
70 * flag, for use with deep request queues).
72 * Bulk endpoints can use any size buffers, and can also be used for interrupt
73 * transfers. interrupt-only endpoints can be much less functional.
75 * NOTE: this is analogous to 'struct urb' on the host side, except that
76 * it's thinner and promotes more pre-allocation.
84 unsigned no_interrupt
:1;
86 unsigned short_not_ok
:1;
88 void (*complete
)(struct usb_ep
*ep
,
89 struct usb_request
*req
);
91 struct list_head list
;
97 /*-------------------------------------------------------------------------*/
99 /* endpoint-specific parts of the api to the usb controller hardware.
100 * unlike the urb model, (de)multiplexing layers are not required.
101 * (so this api could slash overhead if used on the host side...)
103 * note that device side usb controllers commonly differ in how many
104 * endpoints they support, as well as their capabilities.
107 int (*enable
) (struct usb_ep
*ep
,
108 const struct usb_endpoint_descriptor
*desc
);
109 int (*disable
) (struct usb_ep
*ep
);
111 struct usb_request
*(*alloc_request
) (struct usb_ep
*ep
,
113 void (*free_request
) (struct usb_ep
*ep
, struct usb_request
*req
);
115 int (*queue
) (struct usb_ep
*ep
, struct usb_request
*req
,
117 int (*dequeue
) (struct usb_ep
*ep
, struct usb_request
*req
);
119 int (*set_halt
) (struct usb_ep
*ep
, int value
);
120 int (*set_wedge
) (struct usb_ep
*ep
);
122 int (*fifo_status
) (struct usb_ep
*ep
);
123 void (*fifo_flush
) (struct usb_ep
*ep
);
127 * struct usb_ep - device side representation of USB endpoint
128 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
129 * @ops: Function pointers used to access hardware-specific operations.
130 * @ep_list:the gadget's ep_list holds all of its endpoints
131 * @maxpacket:The maximum packet size used on this endpoint. The initial
132 * value can sometimes be reduced (hardware allowing), according to
133 * the endpoint descriptor used to configure the endpoint.
134 * @driver_data:for use by the gadget driver. all other fields are
135 * read-only to gadget drivers.
137 * the bus controller driver lists all the general purpose endpoints in
138 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
139 * and is accessed only in response to a driver setup() callback.
145 const struct usb_ep_ops
*ops
;
146 struct list_head ep_list
;
147 unsigned maxpacket
:16;
150 /*-------------------------------------------------------------------------*/
153 * usb_ep_enable - configure endpoint, making it usable
154 * @ep:the endpoint being configured. may not be the endpoint named "ep0".
155 * drivers discover endpoints through the ep_list of a usb_gadget.
156 * @desc:descriptor for desired behavior. caller guarantees this pointer
157 * remains valid until the endpoint is disabled; the data byte order
158 * is little-endian (usb-standard).
160 * when configurations are set, or when interface settings change, the driver
161 * will enable or disable the relevant endpoints. while it is enabled, an
162 * endpoint may be used for i/o until the driver receives a disconnect() from
163 * the host or until the endpoint is disabled.
165 * the ep0 implementation (which calls this routine) must ensure that the
166 * hardware capabilities of each endpoint match the descriptor provided
167 * for it. for example, an endpoint named "ep2in-bulk" would be usable
168 * for interrupt transfers as well as bulk, but it likely couldn't be used
169 * for iso transfers or for endpoint 14. some endpoints are fully
170 * configurable, with more generic names like "ep-a". (remember that for
171 * USB, "in" means "towards the USB master".)
173 * returns zero, or a negative error code.
175 static inline int usb_ep_enable(struct usb_ep
*ep
,
176 const struct usb_endpoint_descriptor
*desc
)
178 return ep
->ops
->enable(ep
, desc
);
182 * usb_ep_disable - endpoint is no longer usable
183 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
185 * no other task may be using this endpoint when this is called.
186 * any pending and uncompleted requests will complete with status
187 * indicating disconnect (-ESHUTDOWN) before this call returns.
188 * gadget drivers must call usb_ep_enable() again before queueing
189 * requests to the endpoint.
191 * returns zero, or a negative error code.
193 static inline int usb_ep_disable(struct usb_ep
*ep
)
195 return ep
->ops
->disable(ep
);
199 * usb_ep_alloc_request - allocate a request object to use with this endpoint
200 * @ep:the endpoint to be used with with the request
201 * @gfp_flags:GFP_* flags to use
203 * Request objects must be allocated with this call, since they normally
204 * need controller-specific setup and may even need endpoint-specific
205 * resources such as allocation of DMA descriptors.
206 * Requests may be submitted with usb_ep_queue(), and receive a single
207 * completion callback. Free requests with usb_ep_free_request(), when
208 * they are no longer needed.
210 * Returns the request, or null if one could not be allocated.
212 static inline struct usb_request
*usb_ep_alloc_request(struct usb_ep
*ep
,
215 return ep
->ops
->alloc_request(ep
, gfp_flags
);
219 * usb_ep_free_request - frees a request object
220 * @ep:the endpoint associated with the request
221 * @req:the request being freed
223 * Reverses the effect of usb_ep_alloc_request().
224 * Caller guarantees the request is not queued, and that it will
225 * no longer be requeued (or otherwise used).
227 static inline void usb_ep_free_request(struct usb_ep
*ep
,
228 struct usb_request
*req
)
230 ep
->ops
->free_request(ep
, req
);
234 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
235 * @ep:the endpoint associated with the request
236 * @req:the request being submitted
237 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
238 * pre-allocate all necessary memory with the request.
240 * This tells the device controller to perform the specified request through
241 * that endpoint (reading or writing a buffer). When the request completes,
242 * including being canceled by usb_ep_dequeue(), the request's completion
243 * routine is called to return the request to the driver. Any endpoint
244 * (except control endpoints like ep0) may have more than one transfer
245 * request queued; they complete in FIFO order. Once a gadget driver
246 * submits a request, that request may not be examined or modified until it
247 * is given back to that driver through the completion callback.
249 * Each request is turned into one or more packets. The controller driver
250 * never merges adjacent requests into the same packet. OUT transfers
251 * will sometimes use data that's already buffered in the hardware.
252 * Drivers can rely on the fact that the first byte of the request's buffer
253 * always corresponds to the first byte of some USB packet, for both
254 * IN and OUT transfers.
256 * Bulk endpoints can queue any amount of data; the transfer is packetized
257 * automatically. The last packet will be short if the request doesn't fill it
258 * out completely. Zero length packets (ZLPs) should be avoided in portable
259 * protocols since not all usb hardware can successfully handle zero length
260 * packets. (ZLPs may be explicitly written, and may be implicitly written if
261 * the request 'zero' flag is set.) Bulk endpoints may also be used
262 * for interrupt transfers; but the reverse is not true, and some endpoints
263 * won't support every interrupt transfer. (Such as 768 byte packets.)
265 * Interrupt-only endpoints are less functional than bulk endpoints, for
266 * example by not supporting queueing or not handling buffers that are
267 * larger than the endpoint's maxpacket size. They may also treat data
268 * toggle differently.
270 * Control endpoints ... after getting a setup() callback, the driver queues
271 * one response (even if it would be zero length). That enables the
272 * status ack, after transferring data as specified in the response. Setup
273 * functions may return negative error codes to generate protocol stalls.
274 * (Note that some USB device controllers disallow protocol stall responses
275 * in some cases.) When control responses are deferred (the response is
276 * written after the setup callback returns), then usb_ep_set_halt() may be
277 * used on ep0 to trigger protocol stalls. Depending on the controller,
278 * it may not be possible to trigger a status-stage protocol stall when the
279 * data stage is over, that is, from within the response's completion
282 * For periodic endpoints, like interrupt or isochronous ones, the usb host
283 * arranges to poll once per interval, and the gadget driver usually will
284 * have queued some data to transfer at that time.
286 * Returns zero, or a negative error code. Endpoints that are not enabled
287 * report errors; errors will also be
288 * reported when the usb peripheral is disconnected.
290 static inline int usb_ep_queue(struct usb_ep
*ep
,
291 struct usb_request
*req
, gfp_t gfp_flags
)
293 return ep
->ops
->queue(ep
, req
, gfp_flags
);
297 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
298 * @ep:the endpoint associated with the request
299 * @req:the request being canceled
301 * if the request is still active on the endpoint, it is dequeued and its
302 * completion routine is called (with status -ECONNRESET); else a negative
303 * error code is returned.
305 * note that some hardware can't clear out write fifos (to unlink the request
306 * at the head of the queue) except as part of disconnecting from usb. such
307 * restrictions prevent drivers from supporting configuration changes,
308 * even to configuration zero (a "chapter 9" requirement).
310 static inline int usb_ep_dequeue(struct usb_ep
*ep
, struct usb_request
*req
)
312 return ep
->ops
->dequeue(ep
, req
);
316 * usb_ep_set_halt - sets the endpoint halt feature.
317 * @ep: the non-isochronous endpoint being stalled
319 * Use this to stall an endpoint, perhaps as an error report.
320 * Except for control endpoints,
321 * the endpoint stays halted (will not stream any data) until the host
322 * clears this feature; drivers may need to empty the endpoint's request
323 * queue first, to make sure no inappropriate transfers happen.
325 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
326 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
327 * current altsetting, see usb_ep_clear_halt(). When switching altsettings,
328 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
330 * Returns zero, or a negative error code. On success, this call sets
331 * underlying hardware state that blocks data transfers.
332 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
333 * transfer requests are still queued, or if the controller hardware
334 * (usually a FIFO) still holds bytes that the host hasn't collected.
336 static inline int usb_ep_set_halt(struct usb_ep
*ep
)
338 return ep
->ops
->set_halt(ep
, 1);
342 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
343 * @ep:the bulk or interrupt endpoint being reset
345 * Use this when responding to the standard usb "set interface" request,
346 * for endpoints that aren't reconfigured, after clearing any other state
347 * in the endpoint's i/o queue.
349 * Returns zero, or a negative error code. On success, this call clears
350 * the underlying hardware state reflecting endpoint halt and data toggle.
351 * Note that some hardware can't support this request (like pxa2xx_udc),
352 * and accordingly can't correctly implement interface altsettings.
354 static inline int usb_ep_clear_halt(struct usb_ep
*ep
)
356 return ep
->ops
->set_halt(ep
, 0);
360 * usb_ep_set_wedge - sets the halt feature and ignores clear requests
361 * @ep: the endpoint being wedged
363 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
364 * requests. If the gadget driver clears the halt status, it will
365 * automatically unwedge the endpoint.
367 * Returns zero on success, else negative errno.
370 usb_ep_set_wedge(struct usb_ep
*ep
)
372 if (ep
->ops
->set_wedge
)
373 return ep
->ops
->set_wedge(ep
);
375 return ep
->ops
->set_halt(ep
, 1);
379 * usb_ep_fifo_status - returns number of bytes in fifo, or error
380 * @ep: the endpoint whose fifo status is being checked.
382 * FIFO endpoints may have "unclaimed data" in them in certain cases,
383 * such as after aborted transfers. Hosts may not have collected all
384 * the IN data written by the gadget driver (and reported by a request
385 * completion). The gadget driver may not have collected all the data
386 * written OUT to it by the host. Drivers that need precise handling for
387 * fault reporting or recovery may need to use this call.
389 * This returns the number of such bytes in the fifo, or a negative
390 * errno if the endpoint doesn't use a FIFO or doesn't support such
393 static inline int usb_ep_fifo_status(struct usb_ep
*ep
)
395 if (ep
->ops
->fifo_status
)
396 return ep
->ops
->fifo_status(ep
);
402 * usb_ep_fifo_flush - flushes contents of a fifo
403 * @ep: the endpoint whose fifo is being flushed.
405 * This call may be used to flush the "unclaimed data" that may exist in
406 * an endpoint fifo after abnormal transaction terminations. The call
407 * must never be used except when endpoint is not being used for any
408 * protocol translation.
410 static inline void usb_ep_fifo_flush(struct usb_ep
*ep
)
412 if (ep
->ops
->fifo_flush
)
413 ep
->ops
->fifo_flush(ep
);
417 /*-------------------------------------------------------------------------*/
421 /* the rest of the api to the controller hardware: device operations,
422 * which don't involve endpoints (or i/o).
424 struct usb_gadget_ops
{
425 int (*get_frame
)(struct usb_gadget
*);
426 int (*wakeup
)(struct usb_gadget
*);
427 int (*set_selfpowered
) (struct usb_gadget
*, int is_selfpowered
);
428 int (*vbus_session
) (struct usb_gadget
*, int is_active
);
429 int (*vbus_draw
) (struct usb_gadget
*, unsigned mA
);
430 int (*pullup
) (struct usb_gadget
*, int is_on
);
431 int (*ioctl
)(struct usb_gadget
*,
432 unsigned code
, unsigned long param
);
436 * struct usb_gadget - represents a usb slave device
437 * @ops: Function pointers used to access hardware-specific operations.
438 * @ep0: Endpoint zero, used when reading or writing responses to
439 * driver setup() requests
440 * @ep_list: List of other endpoints supported by the device.
441 * @speed: Speed of current connection to USB host.
442 * @is_dualspeed: True if the controller supports both high and full speed
443 * operation. If it does, the gadget driver must also support both.
444 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
445 * gadget driver must provide a USB OTG descriptor.
446 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
447 * is in the Mini-AB jack, and HNP has been used to switch roles
448 * so that the "A" device currently acts as A-Peripheral, not A-Host.
449 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
450 * supports HNP at this port.
451 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
452 * only supports HNP on a different root port.
453 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
454 * enabled HNP support.
455 * @name: Identifies the controller hardware type. Used in diagnostics
456 * and sometimes configuration.
457 * @dev: Driver model state for this abstract device.
459 * Gadgets have a mostly-portable "gadget driver" implementing device
460 * functions, handling all usb configurations and interfaces. Gadget
461 * drivers talk to hardware-specific code indirectly, through ops vectors.
462 * That insulates the gadget driver from hardware details, and packages
463 * the hardware endpoints through generic i/o queues. The "usb_gadget"
464 * and "usb_ep" interfaces provide that insulation from the hardware.
466 * Except for the driver data, all fields in this structure are
467 * read-only to the gadget driver. That driver data is part of the
468 * "driver model" infrastructure in 2.6 (and later) kernels, and for
469 * earlier systems is grouped in a similar structure that's not known
470 * to the rest of the kernel.
472 * Values of the three OTG device feature flags are updated before the
473 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
474 * driver suspend() calls. They are valid only when is_otg, and when the
475 * device is acting as a B-Peripheral (so is_a_peripheral is false).
478 /* readonly to gadget driver */
479 const struct usb_gadget_ops
*ops
;
481 struct list_head ep_list
; /* of usb_ep */
482 enum usb_device_speed speed
;
483 unsigned is_dualspeed
:1;
485 unsigned is_a_peripheral
:1;
486 unsigned b_hnp_enable
:1;
487 unsigned a_hnp_support
:1;
488 unsigned a_alt_hnp_support
:1;
493 static inline void set_gadget_data(struct usb_gadget
*gadget
, void *data
)
494 { dev_set_drvdata(&gadget
->dev
, data
); }
495 static inline void *get_gadget_data(struct usb_gadget
*gadget
)
496 { return dev_get_drvdata(&gadget
->dev
); }
497 static inline struct usb_gadget
*dev_to_usb_gadget(struct device
*dev
)
499 return container_of(dev
, struct usb_gadget
, dev
);
502 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
503 #define gadget_for_each_ep(tmp, gadget) \
504 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
508 * gadget_is_dualspeed - return true iff the hardware handles high speed
509 * @g: controller that might support both high and full speeds
511 static inline int gadget_is_dualspeed(struct usb_gadget
*g
)
513 #ifdef CONFIG_USB_GADGET_DUALSPEED
514 /* runtime test would check "g->is_dualspeed" ... that might be
515 * useful to work around hardware bugs, but is mostly pointless
524 * gadget_is_otg - return true iff the hardware is OTG-ready
525 * @g: controller that might have a Mini-AB connector
527 * This is a runtime test, since kernels with a USB-OTG stack sometimes
528 * run on boards which only have a Mini-B (or Mini-A) connector.
530 static inline int gadget_is_otg(struct usb_gadget
*g
)
532 #ifdef CONFIG_USB_OTG
540 * usb_gadget_frame_number - returns the current frame number
541 * @gadget: controller that reports the frame number
543 * Returns the usb frame number, normally eleven bits from a SOF packet,
544 * or negative errno if this device doesn't support this capability.
546 static inline int usb_gadget_frame_number(struct usb_gadget
*gadget
)
548 return gadget
->ops
->get_frame(gadget
);
552 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
553 * @gadget: controller used to wake up the host
555 * Returns zero on success, else negative error code if the hardware
556 * doesn't support such attempts, or its support has not been enabled
557 * by the usb host. Drivers must return device descriptors that report
558 * their ability to support this, or hosts won't enable it.
560 * This may also try to use SRP to wake the host and start enumeration,
561 * even if OTG isn't otherwise in use. OTG devices may also start
562 * remote wakeup even when hosts don't explicitly enable it.
564 static inline int usb_gadget_wakeup(struct usb_gadget
*gadget
)
566 if (!gadget
->ops
->wakeup
)
568 return gadget
->ops
->wakeup(gadget
);
572 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
573 * @gadget:the device being declared as self-powered
575 * this affects the device status reported by the hardware driver
576 * to reflect that it now has a local power supply.
578 * returns zero on success, else negative errno.
580 static inline int usb_gadget_set_selfpowered(struct usb_gadget
*gadget
)
582 if (!gadget
->ops
->set_selfpowered
)
584 return gadget
->ops
->set_selfpowered(gadget
, 1);
588 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
589 * @gadget:the device being declared as bus-powered
591 * this affects the device status reported by the hardware driver.
592 * some hardware may not support bus-powered operation, in which
593 * case this feature's value can never change.
595 * returns zero on success, else negative errno.
597 static inline int usb_gadget_clear_selfpowered(struct usb_gadget
*gadget
)
599 if (!gadget
->ops
->set_selfpowered
)
601 return gadget
->ops
->set_selfpowered(gadget
, 0);
605 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
606 * @gadget:The device which now has VBUS power.
609 * This call is used by a driver for an external transceiver (or GPIO)
610 * that detects a VBUS power session starting. Common responses include
611 * resuming the controller, activating the D+ (or D-) pullup to let the
612 * host detect that a USB device is attached, and starting to draw power
613 * (8mA or possibly more, especially after SET_CONFIGURATION).
615 * Returns zero on success, else negative errno.
617 static inline int usb_gadget_vbus_connect(struct usb_gadget
*gadget
)
619 if (!gadget
->ops
->vbus_session
)
621 return gadget
->ops
->vbus_session(gadget
, 1);
625 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
626 * @gadget:The device whose VBUS usage is being described
627 * @mA:How much current to draw, in milliAmperes. This should be twice
628 * the value listed in the configuration descriptor bMaxPower field.
630 * This call is used by gadget drivers during SET_CONFIGURATION calls,
631 * reporting how much power the device may consume. For example, this
632 * could affect how quickly batteries are recharged.
634 * Returns zero on success, else negative errno.
636 static inline int usb_gadget_vbus_draw(struct usb_gadget
*gadget
, unsigned mA
)
638 if (!gadget
->ops
->vbus_draw
)
640 return gadget
->ops
->vbus_draw(gadget
, mA
);
644 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
645 * @gadget:the device whose VBUS supply is being described
648 * This call is used by a driver for an external transceiver (or GPIO)
649 * that detects a VBUS power session ending. Common responses include
650 * reversing everything done in usb_gadget_vbus_connect().
652 * Returns zero on success, else negative errno.
654 static inline int usb_gadget_vbus_disconnect(struct usb_gadget
*gadget
)
656 if (!gadget
->ops
->vbus_session
)
658 return gadget
->ops
->vbus_session(gadget
, 0);
662 * usb_gadget_connect - software-controlled connect to USB host
663 * @gadget:the peripheral being connected
665 * Enables the D+ (or potentially D-) pullup. The host will start
666 * enumerating this gadget when the pullup is active and a VBUS session
667 * is active (the link is powered). This pullup is always enabled unless
668 * usb_gadget_disconnect() has been used to disable it.
670 * Returns zero on success, else negative errno.
672 static inline int usb_gadget_connect(struct usb_gadget
*gadget
)
674 if (!gadget
->ops
->pullup
)
676 return gadget
->ops
->pullup(gadget
, 1);
680 * usb_gadget_disconnect - software-controlled disconnect from USB host
681 * @gadget:the peripheral being disconnected
683 * Disables the D+ (or potentially D-) pullup, which the host may see
684 * as a disconnect (when a VBUS session is active). Not all systems
685 * support software pullup controls.
687 * This routine may be used during the gadget driver bind() call to prevent
688 * the peripheral from ever being visible to the USB host, unless later
689 * usb_gadget_connect() is called. For example, user mode components may
690 * need to be activated before the system can talk to hosts.
692 * Returns zero on success, else negative errno.
694 static inline int usb_gadget_disconnect(struct usb_gadget
*gadget
)
696 if (!gadget
->ops
->pullup
)
698 return gadget
->ops
->pullup(gadget
, 0);
702 /*-------------------------------------------------------------------------*/
705 * struct usb_gadget_driver - driver for usb 'slave' devices
706 * @function: String describing the gadget's function
707 * @speed: Highest speed the driver handles.
708 * @setup: Invoked for ep0 control requests that aren't handled by
709 * the hardware level driver. Most calls must be handled by
710 * the gadget driver, including descriptor and configuration
711 * management. The 16 bit members of the setup data are in
712 * USB byte order. Called in_interrupt; this may not sleep. Driver
713 * queues a response to ep0, or returns negative to stall.
714 * @disconnect: Invoked after all transfers have been stopped,
715 * when the host is disconnected. May be called in_interrupt; this
716 * may not sleep. Some devices can't detect disconnect, so this might
717 * not be called except as part of controller shutdown.
718 * @unbind: Invoked when the driver is unbound from a gadget,
719 * usually from rmmod (after a disconnect is reported).
720 * Called in a context that permits sleeping.
721 * @suspend: Invoked on USB suspend. May be called in_interrupt.
722 * @resume: Invoked on USB resume. May be called in_interrupt.
723 * @driver: Driver model state for this driver.
725 * Devices are disabled till a gadget driver successfully bind()s, which
726 * means the driver will handle setup() requests needed to enumerate (and
727 * meet "chapter 9" requirements) then do some useful work.
729 * If gadget->is_otg is true, the gadget driver must provide an OTG
730 * descriptor during enumeration, or else fail the bind() call. In such
731 * cases, no USB traffic may flow until both bind() returns without
732 * having called usb_gadget_disconnect(), and the USB host stack has
735 * Drivers use hardware-specific knowledge to configure the usb hardware.
736 * endpoint addressing is only one of several hardware characteristics that
737 * are in descriptors the ep0 implementation returns from setup() calls.
739 * Except for ep0 implementation, most driver code shouldn't need change to
740 * run on top of different usb controllers. It'll use endpoints set up by
741 * that ep0 implementation.
743 * The usb controller driver handles a few standard usb requests. Those
744 * include set_address, and feature flags for devices, interfaces, and
745 * endpoints (the get_status, set_feature, and clear_feature requests).
747 * Accordingly, the driver's setup() callback must always implement all
748 * get_descriptor requests, returning at least a device descriptor and
749 * a configuration descriptor. Drivers must make sure the endpoint
750 * descriptors match any hardware constraints. Some hardware also constrains
751 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
753 * The driver's setup() callback must also implement set_configuration,
754 * and should also implement set_interface, get_configuration, and
755 * get_interface. Setting a configuration (or interface) is where
756 * endpoints should be activated or (config 0) shut down.
758 * (Note that only the default control endpoint is supported. Neither
759 * hosts nor devices generally support control traffic except to ep0.)
761 * Most devices will ignore USB suspend/resume operations, and so will
762 * not provide those callbacks. However, some may need to change modes
763 * when the host is not longer directing those activities. For example,
764 * local controls (buttons, dials, etc) may need to be re-enabled since
765 * the (remote) host can't do that any longer; or an error state might
766 * be cleared, to make the device behave identically whether or not
767 * power is maintained.
769 struct usb_gadget_driver
{
771 enum usb_device_speed speed
;
772 void (*unbind
)(struct usb_gadget
*);
773 int (*setup
)(struct usb_gadget
*,
774 const struct usb_ctrlrequest
*);
775 void (*disconnect
)(struct usb_gadget
*);
776 void (*suspend
)(struct usb_gadget
*);
777 void (*resume
)(struct usb_gadget
*);
779 /* FIXME support safe rmmod */
780 struct device_driver driver
;
785 /*-------------------------------------------------------------------------*/
787 /* driver modules register and unregister, as usual.
788 * these calls must be made in a context that can sleep.
790 * these will usually be implemented directly by the hardware-dependent
791 * usb bus interface driver, which will only support a single driver.
795 * usb_gadget_probe_driver - probe a gadget driver
796 * @driver: the driver being registered
797 * @bind: the driver's bind callback
800 * Call this in your gadget driver's module initialization function,
801 * to tell the underlying usb controller driver about your driver.
802 * The @bind() function will be called to bind it to a gadget before this
803 * registration call returns. It's expected that the @bind() function will
804 * be in init sections.
806 int usb_gadget_probe_driver(struct usb_gadget_driver
*driver
,
807 int (*bind
)(struct usb_gadget
*));
810 * usb_gadget_unregister_driver - unregister a gadget driver
811 * @driver:the driver being unregistered
814 * Call this in your gadget driver's module cleanup function,
815 * to tell the underlying usb controller that your driver is
816 * going away. If the controller is connected to a USB host,
817 * it will first disconnect(). The driver is also requested
818 * to unbind() and clean up any device state, before this procedure
819 * finally returns. It's expected that the unbind() functions
820 * will in in exit sections, so may not be linked in some kernels.
822 int usb_gadget_unregister_driver(struct usb_gadget_driver
*driver
);
824 /*-------------------------------------------------------------------------*/
826 /* utility to simplify dealing with string descriptors */
829 * struct usb_string - wraps a C string and its USB id
830 * @id:the (nonzero) ID for this string
831 * @s:the string, in UTF-8 encoding
833 * If you're using usb_gadget_get_string(), use this to wrap a string
834 * together with its ID.
842 * struct usb_gadget_strings - a set of USB strings in a given language
843 * @language:identifies the strings' language (0x0409 for en-us)
844 * @strings:array of strings with their ids
846 * If you're using usb_gadget_get_string(), use this to wrap all the
847 * strings for a given language.
849 struct usb_gadget_strings
{
850 u16 language
; /* 0x0409 for en-us */
851 struct usb_string
*strings
;
854 /* put descriptor for string with that id into buf (buflen >= 256) */
855 int usb_gadget_get_string(struct usb_gadget_strings
*table
, int id
, u8
*buf
);
857 /*-------------------------------------------------------------------------*/
859 /* utility to simplify managing config descriptors */
861 /* write vector of descriptors into buffer */
862 int usb_descriptor_fillbuf(void *, unsigned,
863 const struct usb_descriptor_header
**);
865 /* build config descriptor from single descriptor vector */
866 int usb_gadget_config_buf(const struct usb_config_descriptor
*config
,
867 void *buf
, unsigned buflen
, const struct usb_descriptor_header
**desc
);
869 /* copy a NULL-terminated vector of descriptors */
870 struct usb_descriptor_header
**usb_copy_descriptors(
871 struct usb_descriptor_header
**);
873 /* return copy of endpoint descriptor given original descriptor set */
874 struct usb_endpoint_descriptor
*usb_find_endpoint(
875 struct usb_descriptor_header
**src
,
876 struct usb_descriptor_header
**copy
,
877 struct usb_endpoint_descriptor
*match
);
880 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
881 * @v: vector of descriptors
883 static inline void usb_free_descriptors(struct usb_descriptor_header
**v
)
888 /*-------------------------------------------------------------------------*/
890 /* utility wrapping a simple endpoint selection policy */
892 extern struct usb_ep
*usb_ep_autoconfig(struct usb_gadget
*,
893 struct usb_endpoint_descriptor
*);
895 extern void usb_ep_autoconfig_reset(struct usb_gadget
*);
897 #endif /* __LINUX_USB_GADGET_H */