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Linux/include/linux/usb/gadget.h

  1 /*
  2  * <linux/usb/gadget.h>
  3  *
  4  * We call the USB code inside a Linux-based peripheral device a "gadget"
  5  * driver, except for the hardware-specific bus glue.  One USB host can
  6  * master many USB gadgets, but the gadgets are only slaved to one host.
  7  *
  8  *
  9  * (C) Copyright 2002-2004 by David Brownell
 10  * All Rights Reserved.
 11  *
 12  * This software is licensed under the GNU GPL version 2.
 13  */
 14 
 15 #ifndef __LINUX_USB_GADGET_H
 16 #define __LINUX_USB_GADGET_H
 17 
 18 #include <linux/device.h>
 19 #include <linux/errno.h>
 20 #include <linux/init.h>
 21 #include <linux/list.h>
 22 #include <linux/slab.h>
 23 #include <linux/scatterlist.h>
 24 #include <linux/types.h>
 25 #include <linux/workqueue.h>
 26 #include <linux/usb/ch9.h>
 27 
 28 #define UDC_TRACE_STR_MAX       512
 29 
 30 struct usb_ep;
 31 
 32 /**
 33  * struct usb_request - describes one i/o request
 34  * @buf: Buffer used for data.  Always provide this; some controllers
 35  *      only use PIO, or don't use DMA for some endpoints.
 36  * @dma: DMA address corresponding to 'buf'.  If you don't set this
 37  *      field, and the usb controller needs one, it is responsible
 38  *      for mapping and unmapping the buffer.
 39  * @sg: a scatterlist for SG-capable controllers.
 40  * @num_sgs: number of SG entries
 41  * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
 42  * @length: Length of that data
 43  * @stream_id: The stream id, when USB3.0 bulk streams are being used
 44  * @no_interrupt: If true, hints that no completion irq is needed.
 45  *      Helpful sometimes with deep request queues that are handled
 46  *      directly by DMA controllers.
 47  * @zero: If true, when writing data, makes the last packet be "short"
 48  *     by adding a zero length packet as needed;
 49  * @short_not_ok: When reading data, makes short packets be
 50  *     treated as errors (queue stops advancing till cleanup).
 51  * @complete: Function called when request completes, so this request and
 52  *      its buffer may be re-used.  The function will always be called with
 53  *      interrupts disabled, and it must not sleep.
 54  *      Reads terminate with a short packet, or when the buffer fills,
 55  *      whichever comes first.  When writes terminate, some data bytes
 56  *      will usually still be in flight (often in a hardware fifo).
 57  *      Errors (for reads or writes) stop the queue from advancing
 58  *      until the completion function returns, so that any transfers
 59  *      invalidated by the error may first be dequeued.
 60  * @context: For use by the completion callback
 61  * @list: For use by the gadget driver.
 62  * @status: Reports completion code, zero or a negative errno.
 63  *      Normally, faults block the transfer queue from advancing until
 64  *      the completion callback returns.
 65  *      Code "-ESHUTDOWN" indicates completion caused by device disconnect,
 66  *      or when the driver disabled the endpoint.
 67  * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
 68  *      transfers) this may be less than the requested length.  If the
 69  *      short_not_ok flag is set, short reads are treated as errors
 70  *      even when status otherwise indicates successful completion.
 71  *      Note that for writes (IN transfers) some data bytes may still
 72  *      reside in a device-side FIFO when the request is reported as
 73  *      complete.
 74  *
 75  * These are allocated/freed through the endpoint they're used with.  The
 76  * hardware's driver can add extra per-request data to the memory it returns,
 77  * which often avoids separate memory allocations (potential failures),
 78  * later when the request is queued.
 79  *
 80  * Request flags affect request handling, such as whether a zero length
 81  * packet is written (the "zero" flag), whether a short read should be
 82  * treated as an error (blocking request queue advance, the "short_not_ok"
 83  * flag), or hinting that an interrupt is not required (the "no_interrupt"
 84  * flag, for use with deep request queues).
 85  *
 86  * Bulk endpoints can use any size buffers, and can also be used for interrupt
 87  * transfers. interrupt-only endpoints can be much less functional.
 88  *
 89  * NOTE:  this is analogous to 'struct urb' on the host side, except that
 90  * it's thinner and promotes more pre-allocation.
 91  */
 92 
 93 struct usb_request {
 94         void                    *buf;
 95         unsigned                length;
 96         dma_addr_t              dma;
 97 
 98         struct scatterlist      *sg;
 99         unsigned                num_sgs;
100         unsigned                num_mapped_sgs;
101 
102         unsigned                stream_id:16;
103         unsigned                no_interrupt:1;
104         unsigned                zero:1;
105         unsigned                short_not_ok:1;
106 
107         void                    (*complete)(struct usb_ep *ep,
108                                         struct usb_request *req);
109         void                    *context;
110         struct list_head        list;
111 
112         int                     status;
113         unsigned                actual;
114 };
115 
116 /*-------------------------------------------------------------------------*/
117 
118 /* endpoint-specific parts of the api to the usb controller hardware.
119  * unlike the urb model, (de)multiplexing layers are not required.
120  * (so this api could slash overhead if used on the host side...)
121  *
122  * note that device side usb controllers commonly differ in how many
123  * endpoints they support, as well as their capabilities.
124  */
125 struct usb_ep_ops {
126         int (*enable) (struct usb_ep *ep,
127                 const struct usb_endpoint_descriptor *desc);
128         int (*disable) (struct usb_ep *ep);
129 
130         struct usb_request *(*alloc_request) (struct usb_ep *ep,
131                 gfp_t gfp_flags);
132         void (*free_request) (struct usb_ep *ep, struct usb_request *req);
133 
134         int (*queue) (struct usb_ep *ep, struct usb_request *req,
135                 gfp_t gfp_flags);
136         int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
137 
138         int (*set_halt) (struct usb_ep *ep, int value);
139         int (*set_wedge) (struct usb_ep *ep);
140 
141         int (*fifo_status) (struct usb_ep *ep);
142         void (*fifo_flush) (struct usb_ep *ep);
143 };
144 
145 /**
146  * struct usb_ep_caps - endpoint capabilities description
147  * @type_control:Endpoint supports control type (reserved for ep0).
148  * @type_iso:Endpoint supports isochronous transfers.
149  * @type_bulk:Endpoint supports bulk transfers.
150  * @type_int:Endpoint supports interrupt transfers.
151  * @dir_in:Endpoint supports IN direction.
152  * @dir_out:Endpoint supports OUT direction.
153  */
154 struct usb_ep_caps {
155         unsigned type_control:1;
156         unsigned type_iso:1;
157         unsigned type_bulk:1;
158         unsigned type_int:1;
159         unsigned dir_in:1;
160         unsigned dir_out:1;
161 };
162 
163 #define USB_EP_CAPS_TYPE_CONTROL     0x01
164 #define USB_EP_CAPS_TYPE_ISO         0x02
165 #define USB_EP_CAPS_TYPE_BULK        0x04
166 #define USB_EP_CAPS_TYPE_INT         0x08
167 #define USB_EP_CAPS_TYPE_ALL \
168         (USB_EP_CAPS_TYPE_ISO | USB_EP_CAPS_TYPE_BULK | USB_EP_CAPS_TYPE_INT)
169 #define USB_EP_CAPS_DIR_IN           0x01
170 #define USB_EP_CAPS_DIR_OUT          0x02
171 #define USB_EP_CAPS_DIR_ALL  (USB_EP_CAPS_DIR_IN | USB_EP_CAPS_DIR_OUT)
172 
173 #define USB_EP_CAPS(_type, _dir) \
174         { \
175                 .type_control = !!(_type & USB_EP_CAPS_TYPE_CONTROL), \
176                 .type_iso = !!(_type & USB_EP_CAPS_TYPE_ISO), \
177                 .type_bulk = !!(_type & USB_EP_CAPS_TYPE_BULK), \
178                 .type_int = !!(_type & USB_EP_CAPS_TYPE_INT), \
179                 .dir_in = !!(_dir & USB_EP_CAPS_DIR_IN), \
180                 .dir_out = !!(_dir & USB_EP_CAPS_DIR_OUT), \
181         }
182 
183 /**
184  * struct usb_ep - device side representation of USB endpoint
185  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
186  * @ops: Function pointers used to access hardware-specific operations.
187  * @ep_list:the gadget's ep_list holds all of its endpoints
188  * @caps:The structure describing types and directions supported by endoint.
189  * @maxpacket:The maximum packet size used on this endpoint.  The initial
190  *      value can sometimes be reduced (hardware allowing), according to
191  *      the endpoint descriptor used to configure the endpoint.
192  * @maxpacket_limit:The maximum packet size value which can be handled by this
193  *      endpoint. It's set once by UDC driver when endpoint is initialized, and
194  *      should not be changed. Should not be confused with maxpacket.
195  * @max_streams: The maximum number of streams supported
196  *      by this EP (0 - 16, actual number is 2^n)
197  * @mult: multiplier, 'mult' value for SS Isoc EPs
198  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
199  * @driver_data:for use by the gadget driver.
200  * @address: used to identify the endpoint when finding descriptor that
201  *      matches connection speed
202  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
203  *      enabled and remains valid until the endpoint is disabled.
204  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
205  *      descriptor that is used to configure the endpoint
206  *
207  * the bus controller driver lists all the general purpose endpoints in
208  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
209  * and is accessed only in response to a driver setup() callback.
210  */
211 
212 struct usb_ep {
213         void                    *driver_data;
214 
215         const char              *name;
216         const struct usb_ep_ops *ops;
217         struct list_head        ep_list;
218         struct usb_ep_caps      caps;
219         bool                    claimed;
220         bool                    enabled;
221         unsigned                maxpacket:16;
222         unsigned                maxpacket_limit:16;
223         unsigned                max_streams:16;
224         unsigned                mult:2;
225         unsigned                maxburst:5;
226         u8                      address;
227         const struct usb_endpoint_descriptor    *desc;
228         const struct usb_ss_ep_comp_descriptor  *comp_desc;
229 };
230 
231 /*-------------------------------------------------------------------------*/
232 
233 #if IS_ENABLED(CONFIG_USB_GADGET)
234 void usb_ep_set_maxpacket_limit(struct usb_ep *ep, unsigned maxpacket_limit);
235 int usb_ep_enable(struct usb_ep *ep);
236 int usb_ep_disable(struct usb_ep *ep);
237 struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, gfp_t gfp_flags);
238 void usb_ep_free_request(struct usb_ep *ep, struct usb_request *req);
239 int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags);
240 int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req);
241 int usb_ep_set_halt(struct usb_ep *ep);
242 int usb_ep_clear_halt(struct usb_ep *ep);
243 int usb_ep_set_wedge(struct usb_ep *ep);
244 int usb_ep_fifo_status(struct usb_ep *ep);
245 void usb_ep_fifo_flush(struct usb_ep *ep);
246 #else
247 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
248                 unsigned maxpacket_limit)
249 { }
250 static inline int usb_ep_enable(struct usb_ep *ep)
251 { return 0; }
252 static inline int usb_ep_disable(struct usb_ep *ep)
253 { return 0; }
254 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
255                 gfp_t gfp_flags)
256 { return NULL; }
257 static inline void usb_ep_free_request(struct usb_ep *ep,
258                 struct usb_request *req)
259 { }
260 static inline int usb_ep_queue(struct usb_ep *ep, struct usb_request *req,
261                 gfp_t gfp_flags)
262 { return 0; }
263 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
264 { return 0; }
265 static inline int usb_ep_set_halt(struct usb_ep *ep)
266 { return 0; }
267 static inline int usb_ep_clear_halt(struct usb_ep *ep)
268 { return 0; }
269 static inline int usb_ep_set_wedge(struct usb_ep *ep)
270 { return 0; }
271 static inline int usb_ep_fifo_status(struct usb_ep *ep)
272 { return 0; }
273 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
274 { }
275 #endif /* USB_GADGET */
276 
277 /*-------------------------------------------------------------------------*/
278 
279 struct usb_dcd_config_params {
280         __u8  bU1devExitLat;    /* U1 Device exit Latency */
281 #define USB_DEFAULT_U1_DEV_EXIT_LAT     0x01    /* Less then 1 microsec */
282         __le16 bU2DevExitLat;   /* U2 Device exit Latency */
283 #define USB_DEFAULT_U2_DEV_EXIT_LAT     0x1F4   /* Less then 500 microsec */
284 };
285 
286 
287 struct usb_gadget;
288 struct usb_gadget_driver;
289 struct usb_udc;
290 
291 /* the rest of the api to the controller hardware: device operations,
292  * which don't involve endpoints (or i/o).
293  */
294 struct usb_gadget_ops {
295         int     (*get_frame)(struct usb_gadget *);
296         int     (*wakeup)(struct usb_gadget *);
297         int     (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
298         int     (*vbus_session) (struct usb_gadget *, int is_active);
299         int     (*vbus_draw) (struct usb_gadget *, unsigned mA);
300         int     (*pullup) (struct usb_gadget *, int is_on);
301         int     (*ioctl)(struct usb_gadget *,
302                                 unsigned code, unsigned long param);
303         void    (*get_config_params)(struct usb_dcd_config_params *);
304         int     (*udc_start)(struct usb_gadget *,
305                         struct usb_gadget_driver *);
306         int     (*udc_stop)(struct usb_gadget *);
307         struct usb_ep *(*match_ep)(struct usb_gadget *,
308                         struct usb_endpoint_descriptor *,
309                         struct usb_ss_ep_comp_descriptor *);
310 };
311 
312 /**
313  * struct usb_gadget - represents a usb slave device
314  * @work: (internal use) Workqueue to be used for sysfs_notify()
315  * @udc: struct usb_udc pointer for this gadget
316  * @ops: Function pointers used to access hardware-specific operations.
317  * @ep0: Endpoint zero, used when reading or writing responses to
318  *      driver setup() requests
319  * @ep_list: List of other endpoints supported by the device.
320  * @speed: Speed of current connection to USB host.
321  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
322  *      and all slower speeds.
323  * @state: the state we are now (attached, suspended, configured, etc)
324  * @name: Identifies the controller hardware type.  Used in diagnostics
325  *      and sometimes configuration.
326  * @dev: Driver model state for this abstract device.
327  * @out_epnum: last used out ep number
328  * @in_epnum: last used in ep number
329  * @mA: last set mA value
330  * @otg_caps: OTG capabilities of this gadget.
331  * @sg_supported: true if we can handle scatter-gather
332  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
333  *      gadget driver must provide a USB OTG descriptor.
334  * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
335  *      is in the Mini-AB jack, and HNP has been used to switch roles
336  *      so that the "A" device currently acts as A-Peripheral, not A-Host.
337  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
338  *      supports HNP at this port.
339  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
340  *      only supports HNP on a different root port.
341  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
342  *      enabled HNP support.
343  * @hnp_polling_support: OTG device feature flag, indicating if the OTG device
344  *      in peripheral mode can support HNP polling.
345  * @host_request_flag: OTG device feature flag, indicating if A-Peripheral
346  *      or B-Peripheral wants to take host role.
347  * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
348  *      MaxPacketSize.
349  * @is_selfpowered: if the gadget is self-powered.
350  * @deactivated: True if gadget is deactivated - in deactivated state it cannot
351  *      be connected.
352  * @connected: True if gadget is connected.
353  *
354  * Gadgets have a mostly-portable "gadget driver" implementing device
355  * functions, handling all usb configurations and interfaces.  Gadget
356  * drivers talk to hardware-specific code indirectly, through ops vectors.
357  * That insulates the gadget driver from hardware details, and packages
358  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
359  * and "usb_ep" interfaces provide that insulation from the hardware.
360  *
361  * Except for the driver data, all fields in this structure are
362  * read-only to the gadget driver.  That driver data is part of the
363  * "driver model" infrastructure in 2.6 (and later) kernels, and for
364  * earlier systems is grouped in a similar structure that's not known
365  * to the rest of the kernel.
366  *
367  * Values of the three OTG device feature flags are updated before the
368  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
369  * driver suspend() calls.  They are valid only when is_otg, and when the
370  * device is acting as a B-Peripheral (so is_a_peripheral is false).
371  */
372 struct usb_gadget {
373         struct work_struct              work;
374         struct usb_udc                  *udc;
375         /* readonly to gadget driver */
376         const struct usb_gadget_ops     *ops;
377         struct usb_ep                   *ep0;
378         struct list_head                ep_list;        /* of usb_ep */
379         enum usb_device_speed           speed;
380         enum usb_device_speed           max_speed;
381         enum usb_device_state           state;
382         const char                      *name;
383         struct device                   dev;
384         unsigned                        out_epnum;
385         unsigned                        in_epnum;
386         unsigned                        mA;
387         struct usb_otg_caps             *otg_caps;
388 
389         unsigned                        sg_supported:1;
390         unsigned                        is_otg:1;
391         unsigned                        is_a_peripheral:1;
392         unsigned                        b_hnp_enable:1;
393         unsigned                        a_hnp_support:1;
394         unsigned                        a_alt_hnp_support:1;
395         unsigned                        hnp_polling_support:1;
396         unsigned                        host_request_flag:1;
397         unsigned                        quirk_ep_out_aligned_size:1;
398         unsigned                        quirk_altset_not_supp:1;
399         unsigned                        quirk_stall_not_supp:1;
400         unsigned                        quirk_zlp_not_supp:1;
401         unsigned                        is_selfpowered:1;
402         unsigned                        deactivated:1;
403         unsigned                        connected:1;
404 };
405 #define work_to_gadget(w)       (container_of((w), struct usb_gadget, work))
406 
407 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
408         { dev_set_drvdata(&gadget->dev, data); }
409 static inline void *get_gadget_data(struct usb_gadget *gadget)
410         { return dev_get_drvdata(&gadget->dev); }
411 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
412 {
413         return container_of(dev, struct usb_gadget, dev);
414 }
415 
416 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
417 #define gadget_for_each_ep(tmp, gadget) \
418         list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
419 
420 /**
421  * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
422  *      requires quirk_ep_out_aligned_size, otherwise reguens len.
423  * @g: controller to check for quirk
424  * @ep: the endpoint whose maxpacketsize is used to align @len
425  * @len: buffer size's length to align to @ep's maxpacketsize
426  *
427  * This helper is used in case it's required for any reason to check and maybe
428  * align buffer's size to an ep's maxpacketsize.
429  */
430 static inline size_t
431 usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
432 {
433         return !g->quirk_ep_out_aligned_size ? len :
434                         round_up(len, (size_t)ep->desc->wMaxPacketSize);
435 }
436 
437 /**
438  * gadget_is_altset_supported - return true iff the hardware supports
439  *      altsettings
440  * @g: controller to check for quirk
441  */
442 static inline int gadget_is_altset_supported(struct usb_gadget *g)
443 {
444         return !g->quirk_altset_not_supp;
445 }
446 
447 /**
448  * gadget_is_stall_supported - return true iff the hardware supports stalling
449  * @g: controller to check for quirk
450  */
451 static inline int gadget_is_stall_supported(struct usb_gadget *g)
452 {
453         return !g->quirk_stall_not_supp;
454 }
455 
456 /**
457  * gadget_is_zlp_supported - return true iff the hardware supports zlp
458  * @g: controller to check for quirk
459  */
460 static inline int gadget_is_zlp_supported(struct usb_gadget *g)
461 {
462         return !g->quirk_zlp_not_supp;
463 }
464 
465 /**
466  * gadget_is_dualspeed - return true iff the hardware handles high speed
467  * @g: controller that might support both high and full speeds
468  */
469 static inline int gadget_is_dualspeed(struct usb_gadget *g)
470 {
471         return g->max_speed >= USB_SPEED_HIGH;
472 }
473 
474 /**
475  * gadget_is_superspeed() - return true if the hardware handles superspeed
476  * @g: controller that might support superspeed
477  */
478 static inline int gadget_is_superspeed(struct usb_gadget *g)
479 {
480         return g->max_speed >= USB_SPEED_SUPER;
481 }
482 
483 /**
484  * gadget_is_superspeed_plus() - return true if the hardware handles
485  *      superspeed plus
486  * @g: controller that might support superspeed plus
487  */
488 static inline int gadget_is_superspeed_plus(struct usb_gadget *g)
489 {
490         return g->max_speed >= USB_SPEED_SUPER_PLUS;
491 }
492 
493 /**
494  * gadget_is_otg - return true iff the hardware is OTG-ready
495  * @g: controller that might have a Mini-AB connector
496  *
497  * This is a runtime test, since kernels with a USB-OTG stack sometimes
498  * run on boards which only have a Mini-B (or Mini-A) connector.
499  */
500 static inline int gadget_is_otg(struct usb_gadget *g)
501 {
502 #ifdef CONFIG_USB_OTG
503         return g->is_otg;
504 #else
505         return 0;
506 #endif
507 }
508 
509 /*-------------------------------------------------------------------------*/
510 
511 #if IS_ENABLED(CONFIG_USB_GADGET)
512 int usb_gadget_frame_number(struct usb_gadget *gadget);
513 int usb_gadget_wakeup(struct usb_gadget *gadget);
514 int usb_gadget_set_selfpowered(struct usb_gadget *gadget);
515 int usb_gadget_clear_selfpowered(struct usb_gadget *gadget);
516 int usb_gadget_vbus_connect(struct usb_gadget *gadget);
517 int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA);
518 int usb_gadget_vbus_disconnect(struct usb_gadget *gadget);
519 int usb_gadget_connect(struct usb_gadget *gadget);
520 int usb_gadget_disconnect(struct usb_gadget *gadget);
521 int usb_gadget_deactivate(struct usb_gadget *gadget);
522 int usb_gadget_activate(struct usb_gadget *gadget);
523 #else
524 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
525 { return 0; }
526 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
527 { return 0; }
528 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
529 { return 0; }
530 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
531 { return 0; }
532 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
533 { return 0; }
534 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
535 { return 0; }
536 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
537 { return 0; }
538 static inline int usb_gadget_connect(struct usb_gadget *gadget)
539 { return 0; }
540 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
541 { return 0; }
542 static inline int usb_gadget_deactivate(struct usb_gadget *gadget)
543 { return 0; }
544 static inline int usb_gadget_activate(struct usb_gadget *gadget)
545 { return 0; }
546 #endif /* CONFIG_USB_GADGET */
547 
548 /*-------------------------------------------------------------------------*/
549 
550 /**
551  * struct usb_gadget_driver - driver for usb 'slave' devices
552  * @function: String describing the gadget's function
553  * @max_speed: Highest speed the driver handles.
554  * @setup: Invoked for ep0 control requests that aren't handled by
555  *      the hardware level driver. Most calls must be handled by
556  *      the gadget driver, including descriptor and configuration
557  *      management.  The 16 bit members of the setup data are in
558  *      USB byte order. Called in_interrupt; this may not sleep.  Driver
559  *      queues a response to ep0, or returns negative to stall.
560  * @disconnect: Invoked after all transfers have been stopped,
561  *      when the host is disconnected.  May be called in_interrupt; this
562  *      may not sleep.  Some devices can't detect disconnect, so this might
563  *      not be called except as part of controller shutdown.
564  * @bind: the driver's bind callback
565  * @unbind: Invoked when the driver is unbound from a gadget,
566  *      usually from rmmod (after a disconnect is reported).
567  *      Called in a context that permits sleeping.
568  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
569  * @resume: Invoked on USB resume.  May be called in_interrupt.
570  * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
571  *      and should be called in_interrupt.
572  * @driver: Driver model state for this driver.
573  * @udc_name: A name of UDC this driver should be bound to. If udc_name is NULL,
574  *      this driver will be bound to any available UDC.
575  * @pending: UDC core private data used for deferred probe of this driver.
576  * @match_existing_only: If udc is not found, return an error and don't add this
577  *      gadget driver to list of pending driver
578  *
579  * Devices are disabled till a gadget driver successfully bind()s, which
580  * means the driver will handle setup() requests needed to enumerate (and
581  * meet "chapter 9" requirements) then do some useful work.
582  *
583  * If gadget->is_otg is true, the gadget driver must provide an OTG
584  * descriptor during enumeration, or else fail the bind() call.  In such
585  * cases, no USB traffic may flow until both bind() returns without
586  * having called usb_gadget_disconnect(), and the USB host stack has
587  * initialized.
588  *
589  * Drivers use hardware-specific knowledge to configure the usb hardware.
590  * endpoint addressing is only one of several hardware characteristics that
591  * are in descriptors the ep0 implementation returns from setup() calls.
592  *
593  * Except for ep0 implementation, most driver code shouldn't need change to
594  * run on top of different usb controllers.  It'll use endpoints set up by
595  * that ep0 implementation.
596  *
597  * The usb controller driver handles a few standard usb requests.  Those
598  * include set_address, and feature flags for devices, interfaces, and
599  * endpoints (the get_status, set_feature, and clear_feature requests).
600  *
601  * Accordingly, the driver's setup() callback must always implement all
602  * get_descriptor requests, returning at least a device descriptor and
603  * a configuration descriptor.  Drivers must make sure the endpoint
604  * descriptors match any hardware constraints. Some hardware also constrains
605  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
606  *
607  * The driver's setup() callback must also implement set_configuration,
608  * and should also implement set_interface, get_configuration, and
609  * get_interface.  Setting a configuration (or interface) is where
610  * endpoints should be activated or (config 0) shut down.
611  *
612  * (Note that only the default control endpoint is supported.  Neither
613  * hosts nor devices generally support control traffic except to ep0.)
614  *
615  * Most devices will ignore USB suspend/resume operations, and so will
616  * not provide those callbacks.  However, some may need to change modes
617  * when the host is not longer directing those activities.  For example,
618  * local controls (buttons, dials, etc) may need to be re-enabled since
619  * the (remote) host can't do that any longer; or an error state might
620  * be cleared, to make the device behave identically whether or not
621  * power is maintained.
622  */
623 struct usb_gadget_driver {
624         char                    *function;
625         enum usb_device_speed   max_speed;
626         int                     (*bind)(struct usb_gadget *gadget,
627                                         struct usb_gadget_driver *driver);
628         void                    (*unbind)(struct usb_gadget *);
629         int                     (*setup)(struct usb_gadget *,
630                                         const struct usb_ctrlrequest *);
631         void                    (*disconnect)(struct usb_gadget *);
632         void                    (*suspend)(struct usb_gadget *);
633         void                    (*resume)(struct usb_gadget *);
634         void                    (*reset)(struct usb_gadget *);
635 
636         /* FIXME support safe rmmod */
637         struct device_driver    driver;
638 
639         char                    *udc_name;
640         struct list_head        pending;
641         unsigned                match_existing_only:1;
642 };
643 
644 
645 
646 /*-------------------------------------------------------------------------*/
647 
648 /* driver modules register and unregister, as usual.
649  * these calls must be made in a context that can sleep.
650  *
651  * these will usually be implemented directly by the hardware-dependent
652  * usb bus interface driver, which will only support a single driver.
653  */
654 
655 /**
656  * usb_gadget_probe_driver - probe a gadget driver
657  * @driver: the driver being registered
658  * Context: can sleep
659  *
660  * Call this in your gadget driver's module initialization function,
661  * to tell the underlying usb controller driver about your driver.
662  * The @bind() function will be called to bind it to a gadget before this
663  * registration call returns.  It's expected that the @bind() function will
664  * be in init sections.
665  */
666 int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
667 
668 /**
669  * usb_gadget_unregister_driver - unregister a gadget driver
670  * @driver:the driver being unregistered
671  * Context: can sleep
672  *
673  * Call this in your gadget driver's module cleanup function,
674  * to tell the underlying usb controller that your driver is
675  * going away.  If the controller is connected to a USB host,
676  * it will first disconnect().  The driver is also requested
677  * to unbind() and clean up any device state, before this procedure
678  * finally returns.  It's expected that the unbind() functions
679  * will in in exit sections, so may not be linked in some kernels.
680  */
681 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
682 
683 extern int usb_add_gadget_udc_release(struct device *parent,
684                 struct usb_gadget *gadget, void (*release)(struct device *dev));
685 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
686 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
687 extern char *usb_get_gadget_udc_name(void);
688 
689 /*-------------------------------------------------------------------------*/
690 
691 /* utility to simplify dealing with string descriptors */
692 
693 /**
694  * struct usb_string - wraps a C string and its USB id
695  * @id:the (nonzero) ID for this string
696  * @s:the string, in UTF-8 encoding
697  *
698  * If you're using usb_gadget_get_string(), use this to wrap a string
699  * together with its ID.
700  */
701 struct usb_string {
702         u8                      id;
703         const char              *s;
704 };
705 
706 /**
707  * struct usb_gadget_strings - a set of USB strings in a given language
708  * @language:identifies the strings' language (0x0409 for en-us)
709  * @strings:array of strings with their ids
710  *
711  * If you're using usb_gadget_get_string(), use this to wrap all the
712  * strings for a given language.
713  */
714 struct usb_gadget_strings {
715         u16                     language;       /* 0x0409 for en-us */
716         struct usb_string       *strings;
717 };
718 
719 struct usb_gadget_string_container {
720         struct list_head        list;
721         u8                      *stash[0];
722 };
723 
724 /* put descriptor for string with that id into buf (buflen >= 256) */
725 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
726 
727 /*-------------------------------------------------------------------------*/
728 
729 /* utility to simplify managing config descriptors */
730 
731 /* write vector of descriptors into buffer */
732 int usb_descriptor_fillbuf(void *, unsigned,
733                 const struct usb_descriptor_header **);
734 
735 /* build config descriptor from single descriptor vector */
736 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
737         void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
738 
739 /* copy a NULL-terminated vector of descriptors */
740 struct usb_descriptor_header **usb_copy_descriptors(
741                 struct usb_descriptor_header **);
742 
743 /**
744  * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
745  * @v: vector of descriptors
746  */
747 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
748 {
749         kfree(v);
750 }
751 
752 struct usb_function;
753 int usb_assign_descriptors(struct usb_function *f,
754                 struct usb_descriptor_header **fs,
755                 struct usb_descriptor_header **hs,
756                 struct usb_descriptor_header **ss,
757                 struct usb_descriptor_header **ssp);
758 void usb_free_all_descriptors(struct usb_function *f);
759 
760 struct usb_descriptor_header *usb_otg_descriptor_alloc(
761                                 struct usb_gadget *gadget);
762 int usb_otg_descriptor_init(struct usb_gadget *gadget,
763                 struct usb_descriptor_header *otg_desc);
764 /*-------------------------------------------------------------------------*/
765 
766 /* utility to simplify map/unmap of usb_requests to/from DMA */
767 
768 extern int usb_gadget_map_request_by_dev(struct device *dev,
769                 struct usb_request *req, int is_in);
770 extern int usb_gadget_map_request(struct usb_gadget *gadget,
771                 struct usb_request *req, int is_in);
772 
773 extern void usb_gadget_unmap_request_by_dev(struct device *dev,
774                 struct usb_request *req, int is_in);
775 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
776                 struct usb_request *req, int is_in);
777 
778 /*-------------------------------------------------------------------------*/
779 
780 /* utility to set gadget state properly */
781 
782 extern void usb_gadget_set_state(struct usb_gadget *gadget,
783                 enum usb_device_state state);
784 
785 /*-------------------------------------------------------------------------*/
786 
787 /* utility to tell udc core that the bus reset occurs */
788 extern void usb_gadget_udc_reset(struct usb_gadget *gadget,
789                 struct usb_gadget_driver *driver);
790 
791 /*-------------------------------------------------------------------------*/
792 
793 /* utility to give requests back to the gadget layer */
794 
795 extern void usb_gadget_giveback_request(struct usb_ep *ep,
796                 struct usb_request *req);
797 
798 /*-------------------------------------------------------------------------*/
799 
800 /* utility to find endpoint by name */
801 
802 extern struct usb_ep *gadget_find_ep_by_name(struct usb_gadget *g,
803                 const char *name);
804 
805 /*-------------------------------------------------------------------------*/
806 
807 /* utility to check if endpoint caps match descriptor needs */
808 
809 extern int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
810                 struct usb_ep *ep, struct usb_endpoint_descriptor *desc,
811                 struct usb_ss_ep_comp_descriptor *ep_comp);
812 
813 /*-------------------------------------------------------------------------*/
814 
815 /* utility to update vbus status for udc core, it may be scheduled */
816 extern void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status);
817 
818 /*-------------------------------------------------------------------------*/
819 
820 /* utility wrapping a simple endpoint selection policy */
821 
822 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
823                         struct usb_endpoint_descriptor *);
824 
825 
826 extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
827                         struct usb_endpoint_descriptor *,
828                         struct usb_ss_ep_comp_descriptor *);
829 
830 extern void usb_ep_autoconfig_release(struct usb_ep *);
831 
832 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
833 
834 #endif /* __LINUX_USB_GADGET_H */
835 

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