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Linux/include/linux/usb/gadget.h

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * <linux/usb/gadget.h>
  4  *
  5  * We call the USB code inside a Linux-based peripheral device a "gadget"
  6  * driver, except for the hardware-specific bus glue.  One USB host can
  7  * master many USB gadgets, but the gadgets are only slaved to one host.
  8  *
  9  *
 10  * (C) Copyright 2002-2004 by David Brownell
 11  * All Rights Reserved.
 12  *
 13  * This software is licensed under the GNU GPL version 2.
 14  */
 15 
 16 #ifndef __LINUX_USB_GADGET_H
 17 #define __LINUX_USB_GADGET_H
 18 
 19 #include <linux/device.h>
 20 #include <linux/errno.h>
 21 #include <linux/init.h>
 22 #include <linux/list.h>
 23 #include <linux/slab.h>
 24 #include <linux/scatterlist.h>
 25 #include <linux/types.h>
 26 #include <linux/workqueue.h>
 27 #include <linux/usb/ch9.h>
 28 
 29 #define UDC_TRACE_STR_MAX       512
 30 
 31 struct usb_ep;
 32 
 33 /**
 34  * struct usb_request - describes one i/o request
 35  * @buf: Buffer used for data.  Always provide this; some controllers
 36  *      only use PIO, or don't use DMA for some endpoints.
 37  * @dma: DMA address corresponding to 'buf'.  If you don't set this
 38  *      field, and the usb controller needs one, it is responsible
 39  *      for mapping and unmapping the buffer.
 40  * @sg: a scatterlist for SG-capable controllers.
 41  * @num_sgs: number of SG entries
 42  * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
 43  * @length: Length of that data
 44  * @stream_id: The stream id, when USB3.0 bulk streams are being used
 45  * @no_interrupt: If true, hints that no completion irq is needed.
 46  *      Helpful sometimes with deep request queues that are handled
 47  *      directly by DMA controllers.
 48  * @zero: If true, when writing data, makes the last packet be "short"
 49  *     by adding a zero length packet as needed;
 50  * @short_not_ok: When reading data, makes short packets be
 51  *     treated as errors (queue stops advancing till cleanup).
 52  * @dma_mapped: Indicates if request has been mapped to DMA (internal)
 53  * @complete: Function called when request completes, so this request and
 54  *      its buffer may be re-used.  The function will always be called with
 55  *      interrupts disabled, and it must not sleep.
 56  *      Reads terminate with a short packet, or when the buffer fills,
 57  *      whichever comes first.  When writes terminate, some data bytes
 58  *      will usually still be in flight (often in a hardware fifo).
 59  *      Errors (for reads or writes) stop the queue from advancing
 60  *      until the completion function returns, so that any transfers
 61  *      invalidated by the error may first be dequeued.
 62  * @context: For use by the completion callback
 63  * @list: For use by the gadget driver.
 64  * @status: Reports completion code, zero or a negative errno.
 65  *      Normally, faults block the transfer queue from advancing until
 66  *      the completion callback returns.
 67  *      Code "-ESHUTDOWN" indicates completion caused by device disconnect,
 68  *      or when the driver disabled the endpoint.
 69  * @actual: Reports bytes transferred to/from the buffer.  For reads (OUT
 70  *      transfers) this may be less than the requested length.  If the
 71  *      short_not_ok flag is set, short reads are treated as errors
 72  *      even when status otherwise indicates successful completion.
 73  *      Note that for writes (IN transfers) some data bytes may still
 74  *      reside in a device-side FIFO when the request is reported as
 75  *      complete.
 76  *
 77  * These are allocated/freed through the endpoint they're used with.  The
 78  * hardware's driver can add extra per-request data to the memory it returns,
 79  * which often avoids separate memory allocations (potential failures),
 80  * later when the request is queued.
 81  *
 82  * Request flags affect request handling, such as whether a zero length
 83  * packet is written (the "zero" flag), whether a short read should be
 84  * treated as an error (blocking request queue advance, the "short_not_ok"
 85  * flag), or hinting that an interrupt is not required (the "no_interrupt"
 86  * flag, for use with deep request queues).
 87  *
 88  * Bulk endpoints can use any size buffers, and can also be used for interrupt
 89  * transfers. interrupt-only endpoints can be much less functional.
 90  *
 91  * NOTE:  this is analogous to 'struct urb' on the host side, except that
 92  * it's thinner and promotes more pre-allocation.
 93  */
 94 
 95 struct usb_request {
 96         void                    *buf;
 97         unsigned                length;
 98         dma_addr_t              dma;
 99 
100         struct scatterlist      *sg;
101         unsigned                num_sgs;
102         unsigned                num_mapped_sgs;
103 
104         unsigned                stream_id:16;
105         unsigned                no_interrupt:1;
106         unsigned                zero:1;
107         unsigned                short_not_ok:1;
108         unsigned                dma_mapped:1;
109 
110         void                    (*complete)(struct usb_ep *ep,
111                                         struct usb_request *req);
112         void                    *context;
113         struct list_head        list;
114 
115         int                     status;
116         unsigned                actual;
117 };
118 
119 /*-------------------------------------------------------------------------*/
120 
121 /* endpoint-specific parts of the api to the usb controller hardware.
122  * unlike the urb model, (de)multiplexing layers are not required.
123  * (so this api could slash overhead if used on the host side...)
124  *
125  * note that device side usb controllers commonly differ in how many
126  * endpoints they support, as well as their capabilities.
127  */
128 struct usb_ep_ops {
129         int (*enable) (struct usb_ep *ep,
130                 const struct usb_endpoint_descriptor *desc);
131         int (*disable) (struct usb_ep *ep);
132 
133         struct usb_request *(*alloc_request) (struct usb_ep *ep,
134                 gfp_t gfp_flags);
135         void (*free_request) (struct usb_ep *ep, struct usb_request *req);
136 
137         int (*queue) (struct usb_ep *ep, struct usb_request *req,
138                 gfp_t gfp_flags);
139         int (*dequeue) (struct usb_ep *ep, struct usb_request *req);
140 
141         int (*set_halt) (struct usb_ep *ep, int value);
142         int (*set_wedge) (struct usb_ep *ep);
143 
144         int (*fifo_status) (struct usb_ep *ep);
145         void (*fifo_flush) (struct usb_ep *ep);
146 };
147 
148 /**
149  * struct usb_ep_caps - endpoint capabilities description
150  * @type_control:Endpoint supports control type (reserved for ep0).
151  * @type_iso:Endpoint supports isochronous transfers.
152  * @type_bulk:Endpoint supports bulk transfers.
153  * @type_int:Endpoint supports interrupt transfers.
154  * @dir_in:Endpoint supports IN direction.
155  * @dir_out:Endpoint supports OUT direction.
156  */
157 struct usb_ep_caps {
158         unsigned type_control:1;
159         unsigned type_iso:1;
160         unsigned type_bulk:1;
161         unsigned type_int:1;
162         unsigned dir_in:1;
163         unsigned dir_out:1;
164 };
165 
166 #define USB_EP_CAPS_TYPE_CONTROL     0x01
167 #define USB_EP_CAPS_TYPE_ISO         0x02
168 #define USB_EP_CAPS_TYPE_BULK        0x04
169 #define USB_EP_CAPS_TYPE_INT         0x08
170 #define USB_EP_CAPS_TYPE_ALL \
171         (USB_EP_CAPS_TYPE_ISO | USB_EP_CAPS_TYPE_BULK | USB_EP_CAPS_TYPE_INT)
172 #define USB_EP_CAPS_DIR_IN           0x01
173 #define USB_EP_CAPS_DIR_OUT          0x02
174 #define USB_EP_CAPS_DIR_ALL  (USB_EP_CAPS_DIR_IN | USB_EP_CAPS_DIR_OUT)
175 
176 #define USB_EP_CAPS(_type, _dir) \
177         { \
178                 .type_control = !!(_type & USB_EP_CAPS_TYPE_CONTROL), \
179                 .type_iso = !!(_type & USB_EP_CAPS_TYPE_ISO), \
180                 .type_bulk = !!(_type & USB_EP_CAPS_TYPE_BULK), \
181                 .type_int = !!(_type & USB_EP_CAPS_TYPE_INT), \
182                 .dir_in = !!(_dir & USB_EP_CAPS_DIR_IN), \
183                 .dir_out = !!(_dir & USB_EP_CAPS_DIR_OUT), \
184         }
185 
186 /**
187  * struct usb_ep - device side representation of USB endpoint
188  * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
189  * @ops: Function pointers used to access hardware-specific operations.
190  * @ep_list:the gadget's ep_list holds all of its endpoints
191  * @caps:The structure describing types and directions supported by endoint.
192  * @enabled: The current endpoint enabled/disabled state.
193  * @claimed: True if this endpoint is claimed by a function.
194  * @maxpacket:The maximum packet size used on this endpoint.  The initial
195  *      value can sometimes be reduced (hardware allowing), according to
196  *      the endpoint descriptor used to configure the endpoint.
197  * @maxpacket_limit:The maximum packet size value which can be handled by this
198  *      endpoint. It's set once by UDC driver when endpoint is initialized, and
199  *      should not be changed. Should not be confused with maxpacket.
200  * @max_streams: The maximum number of streams supported
201  *      by this EP (0 - 16, actual number is 2^n)
202  * @mult: multiplier, 'mult' value for SS Isoc EPs
203  * @maxburst: the maximum number of bursts supported by this EP (for usb3)
204  * @driver_data:for use by the gadget driver.
205  * @address: used to identify the endpoint when finding descriptor that
206  *      matches connection speed
207  * @desc: endpoint descriptor.  This pointer is set before the endpoint is
208  *      enabled and remains valid until the endpoint is disabled.
209  * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
210  *      descriptor that is used to configure the endpoint
211  *
212  * the bus controller driver lists all the general purpose endpoints in
213  * gadget->ep_list.  the control endpoint (gadget->ep0) is not in that list,
214  * and is accessed only in response to a driver setup() callback.
215  */
216 
217 struct usb_ep {
218         void                    *driver_data;
219 
220         const char              *name;
221         const struct usb_ep_ops *ops;
222         struct list_head        ep_list;
223         struct usb_ep_caps      caps;
224         bool                    claimed;
225         bool                    enabled;
226         unsigned                maxpacket:16;
227         unsigned                maxpacket_limit:16;
228         unsigned                max_streams:16;
229         unsigned                mult:2;
230         unsigned                maxburst:5;
231         u8                      address;
232         const struct usb_endpoint_descriptor    *desc;
233         const struct usb_ss_ep_comp_descriptor  *comp_desc;
234 };
235 
236 /*-------------------------------------------------------------------------*/
237 
238 #if IS_ENABLED(CONFIG_USB_GADGET)
239 void usb_ep_set_maxpacket_limit(struct usb_ep *ep, unsigned maxpacket_limit);
240 int usb_ep_enable(struct usb_ep *ep);
241 int usb_ep_disable(struct usb_ep *ep);
242 struct usb_request *usb_ep_alloc_request(struct usb_ep *ep, gfp_t gfp_flags);
243 void usb_ep_free_request(struct usb_ep *ep, struct usb_request *req);
244 int usb_ep_queue(struct usb_ep *ep, struct usb_request *req, gfp_t gfp_flags);
245 int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req);
246 int usb_ep_set_halt(struct usb_ep *ep);
247 int usb_ep_clear_halt(struct usb_ep *ep);
248 int usb_ep_set_wedge(struct usb_ep *ep);
249 int usb_ep_fifo_status(struct usb_ep *ep);
250 void usb_ep_fifo_flush(struct usb_ep *ep);
251 #else
252 static inline void usb_ep_set_maxpacket_limit(struct usb_ep *ep,
253                 unsigned maxpacket_limit)
254 { }
255 static inline int usb_ep_enable(struct usb_ep *ep)
256 { return 0; }
257 static inline int usb_ep_disable(struct usb_ep *ep)
258 { return 0; }
259 static inline struct usb_request *usb_ep_alloc_request(struct usb_ep *ep,
260                 gfp_t gfp_flags)
261 { return NULL; }
262 static inline void usb_ep_free_request(struct usb_ep *ep,
263                 struct usb_request *req)
264 { }
265 static inline int usb_ep_queue(struct usb_ep *ep, struct usb_request *req,
266                 gfp_t gfp_flags)
267 { return 0; }
268 static inline int usb_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
269 { return 0; }
270 static inline int usb_ep_set_halt(struct usb_ep *ep)
271 { return 0; }
272 static inline int usb_ep_clear_halt(struct usb_ep *ep)
273 { return 0; }
274 static inline int usb_ep_set_wedge(struct usb_ep *ep)
275 { return 0; }
276 static inline int usb_ep_fifo_status(struct usb_ep *ep)
277 { return 0; }
278 static inline void usb_ep_fifo_flush(struct usb_ep *ep)
279 { }
280 #endif /* USB_GADGET */
281 
282 /*-------------------------------------------------------------------------*/
283 
284 struct usb_dcd_config_params {
285         __u8  bU1devExitLat;    /* U1 Device exit Latency */
286 #define USB_DEFAULT_U1_DEV_EXIT_LAT     0x01    /* Less then 1 microsec */
287         __le16 bU2DevExitLat;   /* U2 Device exit Latency */
288 #define USB_DEFAULT_U2_DEV_EXIT_LAT     0x1F4   /* Less then 500 microsec */
289 };
290 
291 
292 struct usb_gadget;
293 struct usb_gadget_driver;
294 struct usb_udc;
295 
296 /* the rest of the api to the controller hardware: device operations,
297  * which don't involve endpoints (or i/o).
298  */
299 struct usb_gadget_ops {
300         int     (*get_frame)(struct usb_gadget *);
301         int     (*wakeup)(struct usb_gadget *);
302         int     (*set_selfpowered) (struct usb_gadget *, int is_selfpowered);
303         int     (*vbus_session) (struct usb_gadget *, int is_active);
304         int     (*vbus_draw) (struct usb_gadget *, unsigned mA);
305         int     (*pullup) (struct usb_gadget *, int is_on);
306         int     (*ioctl)(struct usb_gadget *,
307                                 unsigned code, unsigned long param);
308         void    (*get_config_params)(struct usb_dcd_config_params *);
309         int     (*udc_start)(struct usb_gadget *,
310                         struct usb_gadget_driver *);
311         int     (*udc_stop)(struct usb_gadget *);
312         void    (*udc_set_speed)(struct usb_gadget *, enum usb_device_speed);
313         struct usb_ep *(*match_ep)(struct usb_gadget *,
314                         struct usb_endpoint_descriptor *,
315                         struct usb_ss_ep_comp_descriptor *);
316 };
317 
318 /**
319  * struct usb_gadget - represents a usb slave device
320  * @work: (internal use) Workqueue to be used for sysfs_notify()
321  * @udc: struct usb_udc pointer for this gadget
322  * @ops: Function pointers used to access hardware-specific operations.
323  * @ep0: Endpoint zero, used when reading or writing responses to
324  *      driver setup() requests
325  * @ep_list: List of other endpoints supported by the device.
326  * @speed: Speed of current connection to USB host.
327  * @max_speed: Maximal speed the UDC can handle.  UDC must support this
328  *      and all slower speeds.
329  * @state: the state we are now (attached, suspended, configured, etc)
330  * @name: Identifies the controller hardware type.  Used in diagnostics
331  *      and sometimes configuration.
332  * @dev: Driver model state for this abstract device.
333  * @out_epnum: last used out ep number
334  * @in_epnum: last used in ep number
335  * @mA: last set mA value
336  * @otg_caps: OTG capabilities of this gadget.
337  * @sg_supported: true if we can handle scatter-gather
338  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
339  *      gadget driver must provide a USB OTG descriptor.
340  * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
341  *      is in the Mini-AB jack, and HNP has been used to switch roles
342  *      so that the "A" device currently acts as A-Peripheral, not A-Host.
343  * @a_hnp_support: OTG device feature flag, indicating that the A-Host
344  *      supports HNP at this port.
345  * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
346  *      only supports HNP on a different root port.
347  * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
348  *      enabled HNP support.
349  * @hnp_polling_support: OTG device feature flag, indicating if the OTG device
350  *      in peripheral mode can support HNP polling.
351  * @host_request_flag: OTG device feature flag, indicating if A-Peripheral
352  *      or B-Peripheral wants to take host role.
353  * @quirk_ep_out_aligned_size: epout requires buffer size to be aligned to
354  *      MaxPacketSize.
355  * @quirk_altset_not_supp: UDC controller doesn't support alt settings.
356  * @quirk_stall_not_supp: UDC controller doesn't support stalling.
357  * @quirk_zlp_not_supp: UDC controller doesn't support ZLP.
358  * @quirk_avoids_skb_reserve: udc/platform wants to avoid skb_reserve() in
359  *      u_ether.c to improve performance.
360  * @is_selfpowered: if the gadget is self-powered.
361  * @deactivated: True if gadget is deactivated - in deactivated state it cannot
362  *      be connected.
363  * @connected: True if gadget is connected.
364  * @lpm_capable: If the gadget max_speed is FULL or HIGH, this flag
365  *      indicates that it supports LPM as per the LPM ECN & errata.
366  *
367  * Gadgets have a mostly-portable "gadget driver" implementing device
368  * functions, handling all usb configurations and interfaces.  Gadget
369  * drivers talk to hardware-specific code indirectly, through ops vectors.
370  * That insulates the gadget driver from hardware details, and packages
371  * the hardware endpoints through generic i/o queues.  The "usb_gadget"
372  * and "usb_ep" interfaces provide that insulation from the hardware.
373  *
374  * Except for the driver data, all fields in this structure are
375  * read-only to the gadget driver.  That driver data is part of the
376  * "driver model" infrastructure in 2.6 (and later) kernels, and for
377  * earlier systems is grouped in a similar structure that's not known
378  * to the rest of the kernel.
379  *
380  * Values of the three OTG device feature flags are updated before the
381  * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
382  * driver suspend() calls.  They are valid only when is_otg, and when the
383  * device is acting as a B-Peripheral (so is_a_peripheral is false).
384  */
385 struct usb_gadget {
386         struct work_struct              work;
387         struct usb_udc                  *udc;
388         /* readonly to gadget driver */
389         const struct usb_gadget_ops     *ops;
390         struct usb_ep                   *ep0;
391         struct list_head                ep_list;        /* of usb_ep */
392         enum usb_device_speed           speed;
393         enum usb_device_speed           max_speed;
394         enum usb_device_state           state;
395         const char                      *name;
396         struct device                   dev;
397         unsigned                        out_epnum;
398         unsigned                        in_epnum;
399         unsigned                        mA;
400         struct usb_otg_caps             *otg_caps;
401 
402         unsigned                        sg_supported:1;
403         unsigned                        is_otg:1;
404         unsigned                        is_a_peripheral:1;
405         unsigned                        b_hnp_enable:1;
406         unsigned                        a_hnp_support:1;
407         unsigned                        a_alt_hnp_support:1;
408         unsigned                        hnp_polling_support:1;
409         unsigned                        host_request_flag:1;
410         unsigned                        quirk_ep_out_aligned_size:1;
411         unsigned                        quirk_altset_not_supp:1;
412         unsigned                        quirk_stall_not_supp:1;
413         unsigned                        quirk_zlp_not_supp:1;
414         unsigned                        quirk_avoids_skb_reserve:1;
415         unsigned                        is_selfpowered:1;
416         unsigned                        deactivated:1;
417         unsigned                        connected:1;
418         unsigned                        lpm_capable:1;
419 };
420 #define work_to_gadget(w)       (container_of((w), struct usb_gadget, work))
421 
422 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
423         { dev_set_drvdata(&gadget->dev, data); }
424 static inline void *get_gadget_data(struct usb_gadget *gadget)
425         { return dev_get_drvdata(&gadget->dev); }
426 static inline struct usb_gadget *dev_to_usb_gadget(struct device *dev)
427 {
428         return container_of(dev, struct usb_gadget, dev);
429 }
430 
431 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
432 #define gadget_for_each_ep(tmp, gadget) \
433         list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
434 
435 /**
436  * usb_ep_align - returns @len aligned to ep's maxpacketsize.
437  * @ep: the endpoint whose maxpacketsize is used to align @len
438  * @len: buffer size's length to align to @ep's maxpacketsize
439  *
440  * This helper is used to align buffer's size to an ep's maxpacketsize.
441  */
442 static inline size_t usb_ep_align(struct usb_ep *ep, size_t len)
443 {
444         int max_packet_size = (size_t)usb_endpoint_maxp(ep->desc) & 0x7ff;
445 
446         return round_up(len, max_packet_size);
447 }
448 
449 /**
450  * usb_ep_align_maybe - returns @len aligned to ep's maxpacketsize if gadget
451  *      requires quirk_ep_out_aligned_size, otherwise returns len.
452  * @g: controller to check for quirk
453  * @ep: the endpoint whose maxpacketsize is used to align @len
454  * @len: buffer size's length to align to @ep's maxpacketsize
455  *
456  * This helper is used in case it's required for any reason to check and maybe
457  * align buffer's size to an ep's maxpacketsize.
458  */
459 static inline size_t
460 usb_ep_align_maybe(struct usb_gadget *g, struct usb_ep *ep, size_t len)
461 {
462         return g->quirk_ep_out_aligned_size ? usb_ep_align(ep, len) : len;
463 }
464 
465 /**
466  * gadget_is_altset_supported - return true iff the hardware supports
467  *      altsettings
468  * @g: controller to check for quirk
469  */
470 static inline int gadget_is_altset_supported(struct usb_gadget *g)
471 {
472         return !g->quirk_altset_not_supp;
473 }
474 
475 /**
476  * gadget_is_stall_supported - return true iff the hardware supports stalling
477  * @g: controller to check for quirk
478  */
479 static inline int gadget_is_stall_supported(struct usb_gadget *g)
480 {
481         return !g->quirk_stall_not_supp;
482 }
483 
484 /**
485  * gadget_is_zlp_supported - return true iff the hardware supports zlp
486  * @g: controller to check for quirk
487  */
488 static inline int gadget_is_zlp_supported(struct usb_gadget *g)
489 {
490         return !g->quirk_zlp_not_supp;
491 }
492 
493 /**
494  * gadget_avoids_skb_reserve - return true iff the hardware would like to avoid
495  *      skb_reserve to improve performance.
496  * @g: controller to check for quirk
497  */
498 static inline int gadget_avoids_skb_reserve(struct usb_gadget *g)
499 {
500         return g->quirk_avoids_skb_reserve;
501 }
502 
503 /**
504  * gadget_is_dualspeed - return true iff the hardware handles high speed
505  * @g: controller that might support both high and full speeds
506  */
507 static inline int gadget_is_dualspeed(struct usb_gadget *g)
508 {
509         return g->max_speed >= USB_SPEED_HIGH;
510 }
511 
512 /**
513  * gadget_is_superspeed() - return true if the hardware handles superspeed
514  * @g: controller that might support superspeed
515  */
516 static inline int gadget_is_superspeed(struct usb_gadget *g)
517 {
518         return g->max_speed >= USB_SPEED_SUPER;
519 }
520 
521 /**
522  * gadget_is_superspeed_plus() - return true if the hardware handles
523  *      superspeed plus
524  * @g: controller that might support superspeed plus
525  */
526 static inline int gadget_is_superspeed_plus(struct usb_gadget *g)
527 {
528         return g->max_speed >= USB_SPEED_SUPER_PLUS;
529 }
530 
531 /**
532  * gadget_is_otg - return true iff the hardware is OTG-ready
533  * @g: controller that might have a Mini-AB connector
534  *
535  * This is a runtime test, since kernels with a USB-OTG stack sometimes
536  * run on boards which only have a Mini-B (or Mini-A) connector.
537  */
538 static inline int gadget_is_otg(struct usb_gadget *g)
539 {
540 #ifdef CONFIG_USB_OTG
541         return g->is_otg;
542 #else
543         return 0;
544 #endif
545 }
546 
547 /*-------------------------------------------------------------------------*/
548 
549 #if IS_ENABLED(CONFIG_USB_GADGET)
550 int usb_gadget_frame_number(struct usb_gadget *gadget);
551 int usb_gadget_wakeup(struct usb_gadget *gadget);
552 int usb_gadget_set_selfpowered(struct usb_gadget *gadget);
553 int usb_gadget_clear_selfpowered(struct usb_gadget *gadget);
554 int usb_gadget_vbus_connect(struct usb_gadget *gadget);
555 int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA);
556 int usb_gadget_vbus_disconnect(struct usb_gadget *gadget);
557 int usb_gadget_connect(struct usb_gadget *gadget);
558 int usb_gadget_disconnect(struct usb_gadget *gadget);
559 int usb_gadget_deactivate(struct usb_gadget *gadget);
560 int usb_gadget_activate(struct usb_gadget *gadget);
561 #else
562 static inline int usb_gadget_frame_number(struct usb_gadget *gadget)
563 { return 0; }
564 static inline int usb_gadget_wakeup(struct usb_gadget *gadget)
565 { return 0; }
566 static inline int usb_gadget_set_selfpowered(struct usb_gadget *gadget)
567 { return 0; }
568 static inline int usb_gadget_clear_selfpowered(struct usb_gadget *gadget)
569 { return 0; }
570 static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
571 { return 0; }
572 static inline int usb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
573 { return 0; }
574 static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
575 { return 0; }
576 static inline int usb_gadget_connect(struct usb_gadget *gadget)
577 { return 0; }
578 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
579 { return 0; }
580 static inline int usb_gadget_deactivate(struct usb_gadget *gadget)
581 { return 0; }
582 static inline int usb_gadget_activate(struct usb_gadget *gadget)
583 { return 0; }
584 #endif /* CONFIG_USB_GADGET */
585 
586 /*-------------------------------------------------------------------------*/
587 
588 /**
589  * struct usb_gadget_driver - driver for usb 'slave' devices
590  * @function: String describing the gadget's function
591  * @max_speed: Highest speed the driver handles.
592  * @setup: Invoked for ep0 control requests that aren't handled by
593  *      the hardware level driver. Most calls must be handled by
594  *      the gadget driver, including descriptor and configuration
595  *      management.  The 16 bit members of the setup data are in
596  *      USB byte order. Called in_interrupt; this may not sleep.  Driver
597  *      queues a response to ep0, or returns negative to stall.
598  * @disconnect: Invoked after all transfers have been stopped,
599  *      when the host is disconnected.  May be called in_interrupt; this
600  *      may not sleep.  Some devices can't detect disconnect, so this might
601  *      not be called except as part of controller shutdown.
602  * @bind: the driver's bind callback
603  * @unbind: Invoked when the driver is unbound from a gadget,
604  *      usually from rmmod (after a disconnect is reported).
605  *      Called in a context that permits sleeping.
606  * @suspend: Invoked on USB suspend.  May be called in_interrupt.
607  * @resume: Invoked on USB resume.  May be called in_interrupt.
608  * @reset: Invoked on USB bus reset. It is mandatory for all gadget drivers
609  *      and should be called in_interrupt.
610  * @driver: Driver model state for this driver.
611  * @udc_name: A name of UDC this driver should be bound to. If udc_name is NULL,
612  *      this driver will be bound to any available UDC.
613  * @pending: UDC core private data used for deferred probe of this driver.
614  * @match_existing_only: If udc is not found, return an error and don't add this
615  *      gadget driver to list of pending driver
616  *
617  * Devices are disabled till a gadget driver successfully bind()s, which
618  * means the driver will handle setup() requests needed to enumerate (and
619  * meet "chapter 9" requirements) then do some useful work.
620  *
621  * If gadget->is_otg is true, the gadget driver must provide an OTG
622  * descriptor during enumeration, or else fail the bind() call.  In such
623  * cases, no USB traffic may flow until both bind() returns without
624  * having called usb_gadget_disconnect(), and the USB host stack has
625  * initialized.
626  *
627  * Drivers use hardware-specific knowledge to configure the usb hardware.
628  * endpoint addressing is only one of several hardware characteristics that
629  * are in descriptors the ep0 implementation returns from setup() calls.
630  *
631  * Except for ep0 implementation, most driver code shouldn't need change to
632  * run on top of different usb controllers.  It'll use endpoints set up by
633  * that ep0 implementation.
634  *
635  * The usb controller driver handles a few standard usb requests.  Those
636  * include set_address, and feature flags for devices, interfaces, and
637  * endpoints (the get_status, set_feature, and clear_feature requests).
638  *
639  * Accordingly, the driver's setup() callback must always implement all
640  * get_descriptor requests, returning at least a device descriptor and
641  * a configuration descriptor.  Drivers must make sure the endpoint
642  * descriptors match any hardware constraints. Some hardware also constrains
643  * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
644  *
645  * The driver's setup() callback must also implement set_configuration,
646  * and should also implement set_interface, get_configuration, and
647  * get_interface.  Setting a configuration (or interface) is where
648  * endpoints should be activated or (config 0) shut down.
649  *
650  * (Note that only the default control endpoint is supported.  Neither
651  * hosts nor devices generally support control traffic except to ep0.)
652  *
653  * Most devices will ignore USB suspend/resume operations, and so will
654  * not provide those callbacks.  However, some may need to change modes
655  * when the host is not longer directing those activities.  For example,
656  * local controls (buttons, dials, etc) may need to be re-enabled since
657  * the (remote) host can't do that any longer; or an error state might
658  * be cleared, to make the device behave identically whether or not
659  * power is maintained.
660  */
661 struct usb_gadget_driver {
662         char                    *function;
663         enum usb_device_speed   max_speed;
664         int                     (*bind)(struct usb_gadget *gadget,
665                                         struct usb_gadget_driver *driver);
666         void                    (*unbind)(struct usb_gadget *);
667         int                     (*setup)(struct usb_gadget *,
668                                         const struct usb_ctrlrequest *);
669         void                    (*disconnect)(struct usb_gadget *);
670         void                    (*suspend)(struct usb_gadget *);
671         void                    (*resume)(struct usb_gadget *);
672         void                    (*reset)(struct usb_gadget *);
673 
674         /* FIXME support safe rmmod */
675         struct device_driver    driver;
676 
677         char                    *udc_name;
678         struct list_head        pending;
679         unsigned                match_existing_only:1;
680 };
681 
682 
683 
684 /*-------------------------------------------------------------------------*/
685 
686 /* driver modules register and unregister, as usual.
687  * these calls must be made in a context that can sleep.
688  *
689  * these will usually be implemented directly by the hardware-dependent
690  * usb bus interface driver, which will only support a single driver.
691  */
692 
693 /**
694  * usb_gadget_probe_driver - probe a gadget driver
695  * @driver: the driver being registered
696  * Context: can sleep
697  *
698  * Call this in your gadget driver's module initialization function,
699  * to tell the underlying usb controller driver about your driver.
700  * The @bind() function will be called to bind it to a gadget before this
701  * registration call returns.  It's expected that the @bind() function will
702  * be in init sections.
703  */
704 int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
705 
706 /**
707  * usb_gadget_unregister_driver - unregister a gadget driver
708  * @driver:the driver being unregistered
709  * Context: can sleep
710  *
711  * Call this in your gadget driver's module cleanup function,
712  * to tell the underlying usb controller that your driver is
713  * going away.  If the controller is connected to a USB host,
714  * it will first disconnect().  The driver is also requested
715  * to unbind() and clean up any device state, before this procedure
716  * finally returns.  It's expected that the unbind() functions
717  * will in in exit sections, so may not be linked in some kernels.
718  */
719 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
720 
721 extern int usb_add_gadget_udc_release(struct device *parent,
722                 struct usb_gadget *gadget, void (*release)(struct device *dev));
723 extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
724 extern void usb_del_gadget_udc(struct usb_gadget *gadget);
725 extern char *usb_get_gadget_udc_name(void);
726 
727 /*-------------------------------------------------------------------------*/
728 
729 /* utility to simplify dealing with string descriptors */
730 
731 /**
732  * struct usb_string - wraps a C string and its USB id
733  * @id:the (nonzero) ID for this string
734  * @s:the string, in UTF-8 encoding
735  *
736  * If you're using usb_gadget_get_string(), use this to wrap a string
737  * together with its ID.
738  */
739 struct usb_string {
740         u8                      id;
741         const char              *s;
742 };
743 
744 /**
745  * struct usb_gadget_strings - a set of USB strings in a given language
746  * @language:identifies the strings' language (0x0409 for en-us)
747  * @strings:array of strings with their ids
748  *
749  * If you're using usb_gadget_get_string(), use this to wrap all the
750  * strings for a given language.
751  */
752 struct usb_gadget_strings {
753         u16                     language;       /* 0x0409 for en-us */
754         struct usb_string       *strings;
755 };
756 
757 struct usb_gadget_string_container {
758         struct list_head        list;
759         u8                      *stash[0];
760 };
761 
762 /* put descriptor for string with that id into buf (buflen >= 256) */
763 int usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf);
764 
765 /*-------------------------------------------------------------------------*/
766 
767 /* utility to simplify managing config descriptors */
768 
769 /* write vector of descriptors into buffer */
770 int usb_descriptor_fillbuf(void *, unsigned,
771                 const struct usb_descriptor_header **);
772 
773 /* build config descriptor from single descriptor vector */
774 int usb_gadget_config_buf(const struct usb_config_descriptor *config,
775         void *buf, unsigned buflen, const struct usb_descriptor_header **desc);
776 
777 /* copy a NULL-terminated vector of descriptors */
778 struct usb_descriptor_header **usb_copy_descriptors(
779                 struct usb_descriptor_header **);
780 
781 /**
782  * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
783  * @v: vector of descriptors
784  */
785 static inline void usb_free_descriptors(struct usb_descriptor_header **v)
786 {
787         kfree(v);
788 }
789 
790 struct usb_function;
791 int usb_assign_descriptors(struct usb_function *f,
792                 struct usb_descriptor_header **fs,
793                 struct usb_descriptor_header **hs,
794                 struct usb_descriptor_header **ss,
795                 struct usb_descriptor_header **ssp);
796 void usb_free_all_descriptors(struct usb_function *f);
797 
798 struct usb_descriptor_header *usb_otg_descriptor_alloc(
799                                 struct usb_gadget *gadget);
800 int usb_otg_descriptor_init(struct usb_gadget *gadget,
801                 struct usb_descriptor_header *otg_desc);
802 /*-------------------------------------------------------------------------*/
803 
804 /* utility to simplify map/unmap of usb_requests to/from DMA */
805 
806 extern int usb_gadget_map_request_by_dev(struct device *dev,
807                 struct usb_request *req, int is_in);
808 extern int usb_gadget_map_request(struct usb_gadget *gadget,
809                 struct usb_request *req, int is_in);
810 
811 extern void usb_gadget_unmap_request_by_dev(struct device *dev,
812                 struct usb_request *req, int is_in);
813 extern void usb_gadget_unmap_request(struct usb_gadget *gadget,
814                 struct usb_request *req, int is_in);
815 
816 /*-------------------------------------------------------------------------*/
817 
818 /* utility to set gadget state properly */
819 
820 extern void usb_gadget_set_state(struct usb_gadget *gadget,
821                 enum usb_device_state state);
822 
823 /*-------------------------------------------------------------------------*/
824 
825 /* utility to tell udc core that the bus reset occurs */
826 extern void usb_gadget_udc_reset(struct usb_gadget *gadget,
827                 struct usb_gadget_driver *driver);
828 
829 /*-------------------------------------------------------------------------*/
830 
831 /* utility to give requests back to the gadget layer */
832 
833 extern void usb_gadget_giveback_request(struct usb_ep *ep,
834                 struct usb_request *req);
835 
836 /*-------------------------------------------------------------------------*/
837 
838 /* utility to find endpoint by name */
839 
840 extern struct usb_ep *gadget_find_ep_by_name(struct usb_gadget *g,
841                 const char *name);
842 
843 /*-------------------------------------------------------------------------*/
844 
845 /* utility to check if endpoint caps match descriptor needs */
846 
847 extern int usb_gadget_ep_match_desc(struct usb_gadget *gadget,
848                 struct usb_ep *ep, struct usb_endpoint_descriptor *desc,
849                 struct usb_ss_ep_comp_descriptor *ep_comp);
850 
851 /*-------------------------------------------------------------------------*/
852 
853 /* utility to update vbus status for udc core, it may be scheduled */
854 extern void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status);
855 
856 /*-------------------------------------------------------------------------*/
857 
858 /* utility wrapping a simple endpoint selection policy */
859 
860 extern struct usb_ep *usb_ep_autoconfig(struct usb_gadget *,
861                         struct usb_endpoint_descriptor *);
862 
863 
864 extern struct usb_ep *usb_ep_autoconfig_ss(struct usb_gadget *,
865                         struct usb_endpoint_descriptor *,
866                         struct usb_ss_ep_comp_descriptor *);
867 
868 extern void usb_ep_autoconfig_release(struct usb_ep *);
869 
870 extern void usb_ep_autoconfig_reset(struct usb_gadget *);
871 
872 #endif /* __LINUX_USB_GADGET_H */
873 

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