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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * <linux/usb_gadget.h>
3 *
4 * We call the USB code inside a Linux-based peripheral device a "gadget"
5 * driver, except for the hardware-specific bus glue. One USB host can
6 * master many USB gadgets, but the gadgets are only slaved to one host.
7 *
8 *
9 * (C) Copyright 2002-2004 by David Brownell
10 * All Rights Reserved.
11 *
12 * This software is licensed under the GNU GPL version 2.
13 */
14
15#ifndef __LINUX_USB_GADGET_H
16#define __LINUX_USB_GADGET_H
17
18#ifdef __KERNEL__
19
20struct usb_ep;
21
22/**
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
58 * complete.
59 *
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.
64 *
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).
70 *
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.
73 */
74 // NOTE this is analagous to 'struct urb' on the host side,
75 // except that it's thinner and promotes more pre-allocation.
76
77struct usb_request {
78 void *buf;
79 unsigned length;
80 dma_addr_t dma;
81
82 unsigned no_interrupt:1;
83 unsigned zero:1;
84 unsigned short_not_ok:1;
85
86 void (*complete)(struct usb_ep *ep,
87 struct usb_request *req);
88 void *context;
89 struct list_head list;
90
91 int status;
92 unsigned actual;
93};
94
95/*-------------------------------------------------------------------------*/
96
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...)
100 *
101 * note that device side usb controllers commonly differ in how many
102 * endpoints they support, as well as their capabilities.
103 */
104struct usb_ep_ops {
105 int (*enable) (struct usb_ep *ep,
106 const struct usb_endpoint_descriptor *desc);
107 int (*disable) (struct usb_ep *ep);
108
109 struct usb_request *(*alloc_request) (struct usb_ep *ep,
Al Viro55016f12005-10-21 03:21:58 -0400110 gfp_t gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 void (*free_request) (struct usb_ep *ep, struct usb_request *req);
112
113 void *(*alloc_buffer) (struct usb_ep *ep, unsigned bytes,
Al Viro55016f12005-10-21 03:21:58 -0400114 dma_addr_t *dma, gfp_t gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 void (*free_buffer) (struct usb_ep *ep, void *buf, dma_addr_t dma,
116 unsigned bytes);
117 // NOTE: on 2.6, drivers may also use dma_map() and
118 // dma_sync_single_*() to directly manage dma overhead.
119
120 int (*queue) (struct usb_ep *ep, struct usb_request *req,
Al Viro55016f12005-10-21 03:21:58 -0400121 gfp_t gfp_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
123
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);
127};
128
129/**
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.
139 *
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.
143 */
144struct usb_ep {
145 void *driver_data;
146
147 const char *name;
148 const struct usb_ep_ops *ops;
149 struct list_head ep_list;
150 unsigned maxpacket:16;
151};
152
153/*-------------------------------------------------------------------------*/
154
155/**
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).
162 *
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.
167 *
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".)
175 *
176 * returns zero, or a negative error code.
177 */
178static inline int
179usb_ep_enable (struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
180{
181 return ep->ops->enable (ep, desc);
182}
183
184/**
185 * usb_ep_disable - endpoint is no longer usable
186 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
187 *
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.
193 *
194 * returns zero, or a negative error code.
195 */
196static inline int
197usb_ep_disable (struct usb_ep *ep)
198{
199 return ep->ops->disable (ep);
200}
201
202/**
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
206 *
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.
213 *
214 * Returns the request, or null if one could not be allocated.
215 */
216static inline struct usb_request *
Al Viro55016f12005-10-21 03:21:58 -0400217usb_ep_alloc_request (struct usb_ep *ep, gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
219 return ep->ops->alloc_request (ep, gfp_flags);
220}
221
222/**
223 * usb_ep_free_request - frees a request object
224 * @ep:the endpoint associated with the request
225 * @req:the request being freed
226 *
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).
230 */
231static inline void
232usb_ep_free_request (struct usb_ep *ep, struct usb_request *req)
233{
234 ep->ops->free_request (ep, req);
235}
236
237/**
238 * usb_ep_alloc_buffer - allocate an I/O buffer
239 * @ep:the endpoint associated with the buffer
240 * @len:length of the desired buffer
241 * @dma:pointer to the buffer's DMA address; must be valid
242 * @gfp_flags:GFP_* flags to use
243 *
244 * Returns a new buffer, or null if one could not be allocated.
245 * The buffer is suitably aligned for dma, if that endpoint uses DMA,
246 * and the caller won't have to care about dma-inconsistency
247 * or any hidden "bounce buffer" mechanism. No additional per-request
248 * DMA mapping will be required for such buffers.
249 * Free it later with usb_ep_free_buffer().
250 *
251 * You don't need to use this call to allocate I/O buffers unless you
252 * want to make sure drivers don't incur costs for such "bounce buffer"
253 * copies or per-request DMA mappings.
254 */
255static inline void *
256usb_ep_alloc_buffer (struct usb_ep *ep, unsigned len, dma_addr_t *dma,
Al Viro55016f12005-10-21 03:21:58 -0400257 gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258{
259 return ep->ops->alloc_buffer (ep, len, dma, gfp_flags);
260}
261
262/**
263 * usb_ep_free_buffer - frees an i/o buffer
264 * @ep:the endpoint associated with the buffer
265 * @buf:CPU view address of the buffer
266 * @dma:the buffer's DMA address
267 * @len:length of the buffer
268 *
269 * reverses the effect of usb_ep_alloc_buffer().
270 * caller guarantees the buffer will no longer be accessed
271 */
272static inline void
273usb_ep_free_buffer (struct usb_ep *ep, void *buf, dma_addr_t dma, unsigned len)
274{
275 ep->ops->free_buffer (ep, buf, dma, len);
276}
277
278/**
279 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
280 * @ep:the endpoint associated with the request
281 * @req:the request being submitted
282 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
283 * pre-allocate all necessary memory with the request.
284 *
285 * This tells the device controller to perform the specified request through
286 * that endpoint (reading or writing a buffer). When the request completes,
287 * including being canceled by usb_ep_dequeue(), the request's completion
288 * routine is called to return the request to the driver. Any endpoint
289 * (except control endpoints like ep0) may have more than one transfer
290 * request queued; they complete in FIFO order. Once a gadget driver
291 * submits a request, that request may not be examined or modified until it
292 * is given back to that driver through the completion callback.
293 *
294 * Each request is turned into one or more packets. The controller driver
295 * never merges adjacent requests into the same packet. OUT transfers
296 * will sometimes use data that's already buffered in the hardware.
297 * Drivers can rely on the fact that the first byte of the request's buffer
298 * always corresponds to the first byte of some USB packet, for both
299 * IN and OUT transfers.
300 *
301 * Bulk endpoints can queue any amount of data; the transfer is packetized
302 * automatically. The last packet will be short if the request doesn't fill it
303 * out completely. Zero length packets (ZLPs) should be avoided in portable
304 * protocols since not all usb hardware can successfully handle zero length
305 * packets. (ZLPs may be explicitly written, and may be implicitly written if
306 * the request 'zero' flag is set.) Bulk endpoints may also be used
307 * for interrupt transfers; but the reverse is not true, and some endpoints
308 * won't support every interrupt transfer. (Such as 768 byte packets.)
309 *
310 * Interrupt-only endpoints are less functional than bulk endpoints, for
311 * example by not supporting queueing or not handling buffers that are
312 * larger than the endpoint's maxpacket size. They may also treat data
313 * toggle differently.
314 *
315 * Control endpoints ... after getting a setup() callback, the driver queues
316 * one response (even if it would be zero length). That enables the
317 * status ack, after transfering data as specified in the response. Setup
318 * functions may return negative error codes to generate protocol stalls.
319 * (Note that some USB device controllers disallow protocol stall responses
320 * in some cases.) When control responses are deferred (the response is
321 * written after the setup callback returns), then usb_ep_set_halt() may be
322 * used on ep0 to trigger protocol stalls.
323 *
324 * For periodic endpoints, like interrupt or isochronous ones, the usb host
325 * arranges to poll once per interval, and the gadget driver usually will
326 * have queued some data to transfer at that time.
327 *
328 * Returns zero, or a negative error code. Endpoints that are not enabled
329 * report errors; errors will also be
330 * reported when the usb peripheral is disconnected.
331 */
332static inline int
Al Viro55016f12005-10-21 03:21:58 -0400333usb_ep_queue (struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334{
335 return ep->ops->queue (ep, req, gfp_flags);
336}
337
338/**
339 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
340 * @ep:the endpoint associated with the request
341 * @req:the request being canceled
342 *
343 * if the request is still active on the endpoint, it is dequeued and its
344 * completion routine is called (with status -ECONNRESET); else a negative
345 * error code is returned.
346 *
347 * note that some hardware can't clear out write fifos (to unlink the request
348 * at the head of the queue) except as part of disconnecting from usb. such
349 * restrictions prevent drivers from supporting configuration changes,
350 * even to configuration zero (a "chapter 9" requirement).
351 */
352static inline int usb_ep_dequeue (struct usb_ep *ep, struct usb_request *req)
353{
354 return ep->ops->dequeue (ep, req);
355}
356
357/**
358 * usb_ep_set_halt - sets the endpoint halt feature.
359 * @ep: the non-isochronous endpoint being stalled
360 *
361 * Use this to stall an endpoint, perhaps as an error report.
362 * Except for control endpoints,
363 * the endpoint stays halted (will not stream any data) until the host
364 * clears this feature; drivers may need to empty the endpoint's request
365 * queue first, to make sure no inappropriate transfers happen.
366 *
367 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
368 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
369 * current altsetting, see usb_ep_clear_halt(). When switching altsettings,
370 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
371 *
372 * Returns zero, or a negative error code. On success, this call sets
373 * underlying hardware state that blocks data transfers.
374 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
375 * transfer requests are still queued, or if the controller hardware
376 * (usually a FIFO) still holds bytes that the host hasn't collected.
377 */
378static inline int
379usb_ep_set_halt (struct usb_ep *ep)
380{
381 return ep->ops->set_halt (ep, 1);
382}
383
384/**
385 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
386 * @ep:the bulk or interrupt endpoint being reset
387 *
388 * Use this when responding to the standard usb "set interface" request,
389 * for endpoints that aren't reconfigured, after clearing any other state
390 * in the endpoint's i/o queue.
391 *
392 * Returns zero, or a negative error code. On success, this call clears
393 * the underlying hardware state reflecting endpoint halt and data toggle.
394 * Note that some hardware can't support this request (like pxa2xx_udc),
395 * and accordingly can't correctly implement interface altsettings.
396 */
397static inline int
398usb_ep_clear_halt (struct usb_ep *ep)
399{
400 return ep->ops->set_halt (ep, 0);
401}
402
403/**
404 * usb_ep_fifo_status - returns number of bytes in fifo, or error
405 * @ep: the endpoint whose fifo status is being checked.
406 *
407 * FIFO endpoints may have "unclaimed data" in them in certain cases,
408 * such as after aborted transfers. Hosts may not have collected all
409 * the IN data written by the gadget driver (and reported by a request
410 * completion). The gadget driver may not have collected all the data
411 * written OUT to it by the host. Drivers that need precise handling for
412 * fault reporting or recovery may need to use this call.
413 *
414 * This returns the number of such bytes in the fifo, or a negative
415 * errno if the endpoint doesn't use a FIFO or doesn't support such
416 * precise handling.
417 */
418static inline int
419usb_ep_fifo_status (struct usb_ep *ep)
420{
421 if (ep->ops->fifo_status)
422 return ep->ops->fifo_status (ep);
423 else
424 return -EOPNOTSUPP;
425}
426
427/**
428 * usb_ep_fifo_flush - flushes contents of a fifo
429 * @ep: the endpoint whose fifo is being flushed.
430 *
431 * This call may be used to flush the "unclaimed data" that may exist in
432 * an endpoint fifo after abnormal transaction terminations. The call
433 * must never be used except when endpoint is not being used for any
434 * protocol translation.
435 */
436static inline void
437usb_ep_fifo_flush (struct usb_ep *ep)
438{
439 if (ep->ops->fifo_flush)
440 ep->ops->fifo_flush (ep);
441}
442
443
444/*-------------------------------------------------------------------------*/
445
446struct usb_gadget;
447
448/* the rest of the api to the controller hardware: device operations,
449 * which don't involve endpoints (or i/o).
450 */
451struct usb_gadget_ops {
452 int (*get_frame)(struct usb_gadget *);
453 int (*wakeup)(struct usb_gadget *);
454 int (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
455 int (*vbus_session) (struct usb_gadget *, int is_active);
456 int (*vbus_draw) (struct usb_gadget *, unsigned mA);
457 int (*pullup) (struct usb_gadget *, int is_on);
458 int (*ioctl)(struct usb_gadget *,
459 unsigned code, unsigned long param);
460};
461
462/**
463 * struct usb_gadget - represents a usb slave device
464 * @ops: Function pointers used to access hardware-specific operations.
465 * @ep0: Endpoint zero, used when reading or writing responses to
466 * driver setup() requests
467 * @ep_list: List of other endpoints supported by the device.
468 * @speed: Speed of current connection to USB host.
469 * @is_dualspeed: True if the controller supports both high and full speed
470 * operation. If it does, the gadget driver must also support both.
471 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
472 * gadget driver must provide a USB OTG descriptor.
473 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
474 * is in the Mini-AB jack, and HNP has been used to switch roles
475 * so that the "A" device currently acts as A-Peripheral, not A-Host.
476 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
477 * supports HNP at this port.
478 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
479 * only supports HNP on a different root port.
480 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
481 * enabled HNP support.
482 * @name: Identifies the controller hardware type. Used in diagnostics
483 * and sometimes configuration.
484 * @dev: Driver model state for this abstract device.
485 *
486 * Gadgets have a mostly-portable "gadget driver" implementing device
487 * functions, handling all usb configurations and interfaces. Gadget
488 * drivers talk to hardware-specific code indirectly, through ops vectors.
489 * That insulates the gadget driver from hardware details, and packages
490 * the hardware endpoints through generic i/o queues. The "usb_gadget"
491 * and "usb_ep" interfaces provide that insulation from the hardware.
492 *
493 * Except for the driver data, all fields in this structure are
494 * read-only to the gadget driver. That driver data is part of the
495 * "driver model" infrastructure in 2.6 (and later) kernels, and for
496 * earlier systems is grouped in a similar structure that's not known
497 * to the rest of the kernel.
498 *
499 * Values of the three OTG device feature flags are updated before the
500 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
501 * driver suspend() calls. They are valid only when is_otg, and when the
502 * device is acting as a B-Peripheral (so is_a_peripheral is false).
503 */
504struct usb_gadget {
505 /* readonly to gadget driver */
506 const struct usb_gadget_ops *ops;
507 struct usb_ep *ep0;
508 struct list_head ep_list; /* of usb_ep */
509 enum usb_device_speed speed;
510 unsigned is_dualspeed:1;
511 unsigned is_otg:1;
512 unsigned is_a_peripheral:1;
513 unsigned b_hnp_enable:1;
514 unsigned a_hnp_support:1;
515 unsigned a_alt_hnp_support:1;
516 const char *name;
517 struct device dev;
518};
519
520static inline void set_gadget_data (struct usb_gadget *gadget, void *data)
521 { dev_set_drvdata (&gadget->dev, data); }
522static inline void *get_gadget_data (struct usb_gadget *gadget)
523 { return dev_get_drvdata (&gadget->dev); }
524
525/* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
526#define gadget_for_each_ep(tmp,gadget) \
527 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
528
529
530/**
531 * usb_gadget_frame_number - returns the current frame number
532 * @gadget: controller that reports the frame number
533 *
534 * Returns the usb frame number, normally eleven bits from a SOF packet,
535 * or negative errno if this device doesn't support this capability.
536 */
537static inline int usb_gadget_frame_number (struct usb_gadget *gadget)
538{
539 return gadget->ops->get_frame (gadget);
540}
541
542/**
543 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
544 * @gadget: controller used to wake up the host
545 *
546 * Returns zero on success, else negative error code if the hardware
547 * doesn't support such attempts, or its support has not been enabled
548 * by the usb host. Drivers must return device descriptors that report
549 * their ability to support this, or hosts won't enable it.
550 *
551 * This may also try to use SRP to wake the host and start enumeration,
552 * even if OTG isn't otherwise in use. OTG devices may also start
553 * remote wakeup even when hosts don't explicitly enable it.
554 */
555static inline int usb_gadget_wakeup (struct usb_gadget *gadget)
556{
557 if (!gadget->ops->wakeup)
558 return -EOPNOTSUPP;
559 return gadget->ops->wakeup (gadget);
560}
561
562/**
563 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
564 * @gadget:the device being declared as self-powered
565 *
566 * this affects the device status reported by the hardware driver
567 * to reflect that it now has a local power supply.
568 *
569 * returns zero on success, else negative errno.
570 */
571static inline int
572usb_gadget_set_selfpowered (struct usb_gadget *gadget)
573{
574 if (!gadget->ops->set_selfpowered)
575 return -EOPNOTSUPP;
576 return gadget->ops->set_selfpowered (gadget, 1);
577}
578
579/**
580 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
581 * @gadget:the device being declared as bus-powered
582 *
583 * this affects the device status reported by the hardware driver.
584 * some hardware may not support bus-powered operation, in which
585 * case this feature's value can never change.
586 *
587 * returns zero on success, else negative errno.
588 */
589static inline int
590usb_gadget_clear_selfpowered (struct usb_gadget *gadget)
591{
592 if (!gadget->ops->set_selfpowered)
593 return -EOPNOTSUPP;
594 return gadget->ops->set_selfpowered (gadget, 0);
595}
596
597/**
598 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
599 * @gadget:The device which now has VBUS power.
600 *
601 * This call is used by a driver for an external transceiver (or GPIO)
602 * that detects a VBUS power session starting. Common responses include
603 * resuming the controller, activating the D+ (or D-) pullup to let the
604 * host detect that a USB device is attached, and starting to draw power
605 * (8mA or possibly more, especially after SET_CONFIGURATION).
606 *
607 * Returns zero on success, else negative errno.
608 */
609static inline int
610usb_gadget_vbus_connect(struct usb_gadget *gadget)
611{
612 if (!gadget->ops->vbus_session)
613 return -EOPNOTSUPP;
614 return gadget->ops->vbus_session (gadget, 1);
615}
616
617/**
618 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
619 * @gadget:The device whose VBUS usage is being described
620 * @mA:How much current to draw, in milliAmperes. This should be twice
621 * the value listed in the configuration descriptor bMaxPower field.
622 *
623 * This call is used by gadget drivers during SET_CONFIGURATION calls,
624 * reporting how much power the device may consume. For example, this
625 * could affect how quickly batteries are recharged.
626 *
627 * Returns zero on success, else negative errno.
628 */
629static inline int
630usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
631{
632 if (!gadget->ops->vbus_draw)
633 return -EOPNOTSUPP;
634 return gadget->ops->vbus_draw (gadget, mA);
635}
636
637/**
638 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
639 * @gadget:the device whose VBUS supply is being described
640 *
641 * This call is used by a driver for an external transceiver (or GPIO)
642 * that detects a VBUS power session ending. Common responses include
643 * reversing everything done in usb_gadget_vbus_connect().
644 *
645 * Returns zero on success, else negative errno.
646 */
647static inline int
648usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
649{
650 if (!gadget->ops->vbus_session)
651 return -EOPNOTSUPP;
652 return gadget->ops->vbus_session (gadget, 0);
653}
654
655/**
656 * usb_gadget_connect - software-controlled connect to USB host
657 * @gadget:the peripheral being connected
658 *
659 * Enables the D+ (or potentially D-) pullup. The host will start
660 * enumerating this gadget when the pullup is active and a VBUS session
661 * is active (the link is powered). This pullup is always enabled unless
662 * usb_gadget_disconnect() has been used to disable it.
663 *
664 * Returns zero on success, else negative errno.
665 */
666static inline int
667usb_gadget_connect (struct usb_gadget *gadget)
668{
669 if (!gadget->ops->pullup)
670 return -EOPNOTSUPP;
671 return gadget->ops->pullup (gadget, 1);
672}
673
674/**
675 * usb_gadget_disconnect - software-controlled disconnect from USB host
676 * @gadget:the peripheral being disconnected
677 *
678 * Disables the D+ (or potentially D-) pullup, which the host may see
679 * as a disconnect (when a VBUS session is active). Not all systems
680 * support software pullup controls.
681 *
682 * This routine may be used during the gadget driver bind() call to prevent
683 * the peripheral from ever being visible to the USB host, unless later
684 * usb_gadget_connect() is called. For example, user mode components may
685 * need to be activated before the system can talk to hosts.
686 *
687 * Returns zero on success, else negative errno.
688 */
689static inline int
690usb_gadget_disconnect (struct usb_gadget *gadget)
691{
692 if (!gadget->ops->pullup)
693 return -EOPNOTSUPP;
694 return gadget->ops->pullup (gadget, 0);
695}
696
697
698
699/*-------------------------------------------------------------------------*/
700
701/**
702 * struct usb_gadget_driver - driver for usb 'slave' devices
703 * @function: String describing the gadget's function
704 * @speed: Highest speed the driver handles.
705 * @bind: Invoked when the driver is bound to a gadget, usually
706 * after registering the driver.
707 * At that point, ep0 is fully initialized, and ep_list holds
708 * the currently-available endpoints.
709 * Called in a context that permits sleeping.
710 * @setup: Invoked for ep0 control requests that aren't handled by
711 * the hardware level driver. Most calls must be handled by
712 * the gadget driver, including descriptor and configuration
713 * management. The 16 bit members of the setup data are in
David Brownell1bbc1692005-05-07 13:05:13 -0700714 * USB byte order. Called in_interrupt; this may not sleep. Driver
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 * queues a response to ep0, or returns negative to stall.
716 * @disconnect: Invoked after all transfers have been stopped,
717 * when the host is disconnected. May be called in_interrupt; this
718 * may not sleep. Some devices can't detect disconnect, so this might
719 * not be called except as part of controller shutdown.
720 * @unbind: Invoked when the driver is unbound from a gadget,
721 * usually from rmmod (after a disconnect is reported).
722 * Called in a context that permits sleeping.
723 * @suspend: Invoked on USB suspend. May be called in_interrupt.
724 * @resume: Invoked on USB resume. May be called in_interrupt.
725 * @driver: Driver model state for this driver.
726 *
727 * Devices are disabled till a gadget driver successfully bind()s, which
728 * means the driver will handle setup() requests needed to enumerate (and
729 * meet "chapter 9" requirements) then do some useful work.
730 *
731 * If gadget->is_otg is true, the gadget driver must provide an OTG
732 * descriptor during enumeration, or else fail the bind() call. In such
733 * cases, no USB traffic may flow until both bind() returns without
734 * having called usb_gadget_disconnect(), and the USB host stack has
735 * initialized.
736 *
737 * Drivers use hardware-specific knowledge to configure the usb hardware.
738 * endpoint addressing is only one of several hardware characteristics that
739 * are in descriptors the ep0 implementation returns from setup() calls.
740 *
741 * Except for ep0 implementation, most driver code shouldn't need change to
742 * run on top of different usb controllers. It'll use endpoints set up by
743 * that ep0 implementation.
744 *
745 * The usb controller driver handles a few standard usb requests. Those
746 * include set_address, and feature flags for devices, interfaces, and
747 * endpoints (the get_status, set_feature, and clear_feature requests).
748 *
749 * Accordingly, the driver's setup() callback must always implement all
750 * get_descriptor requests, returning at least a device descriptor and
751 * a configuration descriptor. Drivers must make sure the endpoint
752 * descriptors match any hardware constraints. Some hardware also constrains
753 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
754 *
755 * The driver's setup() callback must also implement set_configuration,
756 * and should also implement set_interface, get_configuration, and
757 * get_interface. Setting a configuration (or interface) is where
758 * endpoints should be activated or (config 0) shut down.
759 *
760 * (Note that only the default control endpoint is supported. Neither
761 * hosts nor devices generally support control traffic except to ep0.)
762 *
763 * Most devices will ignore USB suspend/resume operations, and so will
764 * not provide those callbacks. However, some may need to change modes
765 * when the host is not longer directing those activities. For example,
766 * local controls (buttons, dials, etc) may need to be re-enabled since
767 * the (remote) host can't do that any longer; or an error state might
768 * be cleared, to make the device behave identically whether or not
769 * power is maintained.
770 */
771struct usb_gadget_driver {
772 char *function;
773 enum usb_device_speed speed;
774 int (*bind)(struct usb_gadget *);
775 void (*unbind)(struct usb_gadget *);
776 int (*setup)(struct usb_gadget *,
777 const struct usb_ctrlrequest *);
778 void (*disconnect)(struct usb_gadget *);
779 void (*suspend)(struct usb_gadget *);
780 void (*resume)(struct usb_gadget *);
781
782 // FIXME support safe rmmod
783 struct device_driver driver;
784};
785
786
787
788/*-------------------------------------------------------------------------*/
789
790/* driver modules register and unregister, as usual.
791 * these calls must be made in a context that can sleep.
792 *
793 * these will usually be implemented directly by the hardware-dependent
794 * usb bus interface driver, which will only support a single driver.
795 */
796
797/**
798 * usb_gadget_register_driver - register a gadget driver
799 * @driver:the driver being registered
800 *
801 * Call this in your gadget driver's module initialization function,
802 * to tell the underlying usb controller driver about your driver.
803 * The driver's bind() function will be called to bind it to a
David Brownell329af282006-02-18 12:31:05 -0800804 * gadget before this registration call returns. It's expected that
805 * the bind() functions will be in init sections.
806 * This function must be called in a context that can sleep.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 */
808int usb_gadget_register_driver (struct usb_gadget_driver *driver);
809
810/**
811 * usb_gadget_unregister_driver - unregister a gadget driver
812 * @driver:the driver being unregistered
813 *
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
David Brownell329af282006-02-18 12:31:05 -0800819 * finally returns. It's expected that the unbind() functions
820 * will in in exit sections, so may not be linked in some kernels.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 * This function must be called in a context that can sleep.
822 */
823int usb_gadget_unregister_driver (struct usb_gadget_driver *driver);
824
825/*-------------------------------------------------------------------------*/
826
827/* utility to simplify dealing with string descriptors */
828
829/**
830 * struct usb_string - wraps a C string and its USB id
831 * @id:the (nonzero) ID for this string
832 * @s:the string, in UTF-8 encoding
833 *
834 * If you're using usb_gadget_get_string(), use this to wrap a string
835 * together with its ID.
836 */
837struct usb_string {
838 u8 id;
839 const char *s;
840};
841
842/**
843 * struct usb_gadget_strings - a set of USB strings in a given language
844 * @language:identifies the strings' language (0x0409 for en-us)
845 * @strings:array of strings with their ids
846 *
847 * If you're using usb_gadget_get_string(), use this to wrap all the
848 * strings for a given language.
849 */
850struct usb_gadget_strings {
851 u16 language; /* 0x0409 for en-us */
852 struct usb_string *strings;
853};
854
855/* put descriptor for string with that id into buf (buflen >= 256) */
856int usb_gadget_get_string (struct usb_gadget_strings *table, int id, u8 *buf);
857
858/*-------------------------------------------------------------------------*/
859
860/* utility to simplify managing config descriptors */
861
862/* write vector of descriptors into buffer */
863int usb_descriptor_fillbuf(void *, unsigned,
864 const struct usb_descriptor_header **);
865
866/* build config descriptor from single descriptor vector */
867int usb_gadget_config_buf(const struct usb_config_descriptor *config,
868 void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
869
870/*-------------------------------------------------------------------------*/
871
872/* utility wrapping a simple endpoint selection policy */
873
874extern struct usb_ep *usb_ep_autoconfig (struct usb_gadget *,
David Brownella3536782006-07-06 15:48:53 -0700875 struct usb_endpoint_descriptor *) __devinit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876
David Brownella3536782006-07-06 15:48:53 -0700877extern void usb_ep_autoconfig_reset (struct usb_gadget *) __devinit;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878
879#endif /* __KERNEL__ */
880
881#endif /* __LINUX_USB_GADGET_H */