2 * Internal header for libusbx
3 * Copyright © 2007-2009 Daniel Drake <dsd@gentoo.org>
4 * Copyright © 2001 Johannes Erdfelt <johannes@erdfelt.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
40 /* Inside the libusbx code, mark all public functions as follows:
41 * return_type API_EXPORTED function_name(params) { ... }
42 * But if the function returns a pointer, mark it as follows:
43 * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
44 * In the libusbx public header, mark all declarations as:
45 * return_type LIBUSB_CALL function_name(params);
47 #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
49 #define DEVICE_DESC_LENGTH 18
51 #define USB_MAXENDPOINTS 32
52 #define USB_MAXINTERFACES 32
53 #define USB_MAXCONFIG 8
55 /* Backend specific capabilities */
56 #define USBI_CAP_HAS_HID_ACCESS 0x00010000
57 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
59 /* The following is used to silence warnings for unused variables */
60 #define UNUSED(var) do { (void)(var); } while(0)
63 struct list_head *prev, *next;
66 /* Get an entry from the list
67 * ptr - the address of this list_head element in "type"
68 * type - the data type that contains "member"
69 * member - the list_head element in "type"
71 #define list_entry(ptr, type, member) \
72 ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
74 /* Get each entry from a list
75 * pos - A structure pointer has a "member" element
77 * member - the list_head element in "pos"
78 * type - the type of the first parameter
80 #define list_for_each_entry(pos, head, member, type) \
81 for (pos = list_entry((head)->next, type, member); \
82 &pos->member != (head); \
83 pos = list_entry(pos->member.next, type, member))
85 #define list_for_each_entry_safe(pos, n, head, member, type) \
86 for (pos = list_entry((head)->next, type, member), \
87 n = list_entry(pos->member.next, type, member); \
88 &pos->member != (head); \
89 pos = n, n = list_entry(n->member.next, type, member))
91 #define list_empty(entry) ((entry)->next == (entry))
93 static inline void list_init(struct list_head *entry)
95 entry->prev = entry->next = entry;
98 static inline void list_add(struct list_head *entry, struct list_head *head)
100 entry->next = head->next;
103 head->next->prev = entry;
107 static inline void list_add_tail(struct list_head *entry,
108 struct list_head *head)
111 entry->prev = head->prev;
113 head->prev->next = entry;
117 static inline void list_del(struct list_head *entry)
119 entry->next->prev = entry->prev;
120 entry->prev->next = entry->next;
121 entry->next = entry->prev = NULL;
124 static inline void *usbi_reallocf(void *ptr, size_t size)
126 void *ret = realloc(ptr, size);
132 #define container_of(ptr, type, member) ({ \
133 const typeof( ((type *)0)->member ) *mptr = (ptr); \
134 (type *)( (char *)mptr - offsetof(type,member) );})
136 #define MIN(a, b) ((a) < (b) ? (a) : (b))
137 #define MAX(a, b) ((a) > (b) ? (a) : (b))
139 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
141 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
142 const char *function, const char *format, ...);
144 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
145 const char *function, const char *format, va_list args);
147 #if !defined(_MSC_VER) || _MSC_VER >= 1400
149 #ifdef ENABLE_LOGGING
150 #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
151 #define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
153 #define _usbi_log(ctx, level, ...) do { (void)(ctx); } while(0)
154 #define usbi_dbg(...) do {} while(0)
157 #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
158 #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
159 #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
161 #else /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
163 #ifdef ENABLE_LOGGING
164 #define LOG_BODY(ctxt, level) \
167 va_start (args, format); \
168 usbi_log_v(ctxt, level, "", format, args); \
172 #define LOG_BODY(ctxt, level) do { (void)(ctxt); } while(0)
175 static inline void usbi_info(struct libusb_context *ctx, const char *format,
177 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_INFO)
178 static inline void usbi_warn(struct libusb_context *ctx, const char *format,
180 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_WARNING)
181 static inline void usbi_err( struct libusb_context *ctx, const char *format,
183 LOG_BODY(ctx,LIBUSB_LOG_LEVEL_ERROR)
185 static inline void usbi_dbg(const char *format, ...)
186 LOG_BODY(NULL,LIBUSB_LOG_LEVEL_DEBUG)
188 #endif /* !defined(_MSC_VER) || _MSC_VER >= 1400 */
190 #define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
191 #define DEVICE_CTX(dev) ((dev)->ctx)
192 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
193 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
194 #define ITRANSFER_CTX(transfer) \
195 (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
197 #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
198 #define IS_EPOUT(ep) (!IS_EPIN(ep))
199 #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
200 #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
202 /* Internal abstraction for thread synchronization */
203 #if defined(THREADS_POSIX)
204 #include "os/threads_posix.h"
205 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
206 #include <os/threads_windows.h>
209 extern struct libusb_context *usbi_default_context;
211 struct libusb_context {
215 /* internal control pipe, used for interrupting event handling when
216 * something needs to modify poll fds. */
219 struct list_head usb_devs;
220 usbi_mutex_t usb_devs_lock;
222 /* A list of open handles. Backends are free to traverse this if required.
224 struct list_head open_devs;
225 usbi_mutex_t open_devs_lock;
227 /* this is a list of in-flight transfer handles, sorted by timeout
228 * expiration. URBs to timeout the soonest are placed at the beginning of
229 * the list, URBs that will time out later are placed after, and urbs with
230 * infinite timeout are always placed at the very end. */
231 struct list_head flying_transfers;
232 usbi_mutex_t flying_transfers_lock;
234 /* list of poll fds */
235 struct list_head pollfds;
236 usbi_mutex_t pollfds_lock;
238 /* a counter that is set when we want to interrupt event handling, in order
239 * to modify the poll fd set. and a lock to protect it. */
240 unsigned int pollfd_modify;
241 usbi_mutex_t pollfd_modify_lock;
243 /* user callbacks for pollfd changes */
244 libusb_pollfd_added_cb fd_added_cb;
245 libusb_pollfd_removed_cb fd_removed_cb;
246 void *fd_cb_user_data;
248 /* ensures that only one thread is handling events at any one time */
249 usbi_mutex_t events_lock;
251 /* used to see if there is an active thread doing event handling */
252 int event_handler_active;
254 /* used to wait for event completion in threads other than the one that is
256 usbi_mutex_t event_waiters_lock;
257 usbi_cond_t event_waiters_cond;
259 #ifdef USBI_TIMERFD_AVAILABLE
260 /* used for timeout handling, if supported by OS.
261 * this timerfd is maintained to trigger on the next pending timeout */
265 struct list_head list;
268 #ifdef USBI_TIMERFD_AVAILABLE
269 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
271 #define usbi_using_timerfd(ctx) (0)
274 struct libusb_device {
275 /* lock protects refcnt, everything else is finalized at initialization
280 struct libusb_context *ctx;
284 struct libusb_device* parent_dev;
285 uint8_t device_address;
286 uint8_t num_configurations;
287 enum libusb_speed speed;
289 struct list_head list;
290 unsigned long session_data;
292 struct libusb_device_descriptor device_descriptor;
294 unsigned char os_priv[0];
297 struct libusb_device_handle {
298 /* lock protects claimed_interfaces */
300 unsigned long claimed_interfaces;
302 struct list_head list;
303 struct libusb_device *dev;
304 unsigned char os_priv[0];
308 USBI_CLOCK_MONOTONIC,
312 /* in-memory transfer layout:
314 * 1. struct usbi_transfer
315 * 2. struct libusb_transfer (which includes iso packets) [variable size]
316 * 3. os private data [variable size]
318 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
319 * appropriate number of bytes.
320 * the usbi_transfer includes the number of allocated packets, so you can
321 * determine the size of the transfer and hence the start and length of the
325 struct usbi_transfer {
327 struct list_head list;
328 struct timeval timeout;
332 /* this lock is held during libusb_submit_transfer() and
333 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
334 * cancellation, submission-during-cancellation, etc). the OS backend
335 * should also take this lock in the handle_events path, to prevent the user
336 * cancelling the transfer from another thread while you are processing
337 * its completion (presumably there would be races within your OS backend
338 * if this were possible). */
342 enum usbi_transfer_flags {
343 /* The transfer has timed out */
344 USBI_TRANSFER_TIMED_OUT = 1 << 0,
346 /* Set by backend submit_transfer() if the OS handles timeout */
347 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 1,
349 /* Cancellation was requested via libusb_cancel_transfer() */
350 USBI_TRANSFER_CANCELLING = 1 << 2,
352 /* Operation on the transfer failed because the device disappeared */
353 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 3,
355 /* Set by backend submit_transfer() if the fds in use have been updated */
356 USBI_TRANSFER_UPDATED_FDS = 1 << 4,
359 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
360 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
361 + sizeof(struct usbi_transfer)))
362 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
363 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
364 - sizeof(struct usbi_transfer)))
366 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
368 return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
369 + sizeof(struct libusb_transfer)
370 + (transfer->num_iso_packets
371 * sizeof(struct libusb_iso_packet_descriptor));
376 /* All standard descriptors have these 2 fields in common */
377 struct usb_descriptor_header {
379 uint8_t bDescriptorType;
382 /* shared data and functions */
384 int usbi_io_init(struct libusb_context *ctx);
385 void usbi_io_exit(struct libusb_context *ctx);
387 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
388 unsigned long session_id);
389 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
390 unsigned long session_id);
391 int usbi_sanitize_device(struct libusb_device *dev);
392 void usbi_handle_disconnect(struct libusb_device_handle *handle);
394 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
395 enum libusb_transfer_status status);
396 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
398 int usbi_parse_descriptor(unsigned char *source, const char *descriptor,
399 void *dest, int host_endian);
400 int usbi_device_cache_descriptor(libusb_device *dev);
401 int usbi_get_config_index_by_value(struct libusb_device *dev,
402 uint8_t bConfigurationValue, int *idx);
404 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
405 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD)
407 #include "os/poll_posix.h"
408 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
409 #include <os/poll_windows.h>
412 #if (defined(OS_WINDOWS) || defined(OS_WINCE)) && !defined(__GCC__)
413 #undef HAVE_GETTIMEOFDAY
414 int usbi_gettimeofday(struct timeval *tp, void *tzp);
415 #define LIBUSB_GETTIMEOFDAY_WIN32
416 #define HAVE_USBI_GETTIMEOFDAY
418 #ifdef HAVE_GETTIMEOFDAY
419 #define usbi_gettimeofday(tv, tz) gettimeofday((tv), (tz))
420 #define HAVE_USBI_GETTIMEOFDAY
425 /* must come first */
426 struct libusb_pollfd pollfd;
428 struct list_head list;
431 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
432 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
433 void usbi_fd_notification(struct libusb_context *ctx);
435 /* device discovery */
437 /* we traverse usbfs without knowing how many devices we are going to find.
438 * so we create this discovered_devs model which is similar to a linked-list
439 * which grows when required. it can be freed once discovery has completed,
440 * eliminating the need for a list node in the libusb_device structure
442 struct discovered_devs {
445 struct libusb_device *devices[0];
448 struct discovered_devs *discovered_devs_append(
449 struct discovered_devs *discdevs, struct libusb_device *dev);
453 /* This is the interface that OS backends need to implement.
454 * All fields are mandatory, except ones explicitly noted as optional. */
455 struct usbi_os_backend {
456 /* A human-readable name for your backend, e.g. "Linux usbfs" */
459 /* Binary mask for backend specific capabilities */
462 /* Perform initialization of your backend. You might use this function
463 * to determine specific capabilities of the system, allocate required
464 * data structures for later, etc.
466 * This function is called when a libusbx user initializes the library
469 * Return 0 on success, or a LIBUSB_ERROR code on failure.
471 int (*init)(struct libusb_context *ctx);
473 /* Deinitialization. Optional. This function should destroy anything
474 * that was set up by init.
476 * This function is called when the user deinitializes the library.
480 /* Enumerate all the USB devices on the system, returning them in a list
481 * of discovered devices.
483 * Your implementation should enumerate all devices on the system,
484 * regardless of whether they have been seen before or not.
486 * When you have found a device, compute a session ID for it. The session
487 * ID should uniquely represent that particular device for that particular
488 * connection session since boot (i.e. if you disconnect and reconnect a
489 * device immediately after, it should be assigned a different session ID).
490 * If your OS cannot provide a unique session ID as described above,
491 * presenting a session ID of (bus_number << 8 | device_address) should
492 * be sufficient. Bus numbers and device addresses wrap and get reused,
493 * but that is an unlikely case.
495 * After computing a session ID for a device, call
496 * usbi_get_device_by_session_id(). This function checks if libusbx already
497 * knows about the device, and if so, it provides you with a libusb_device
500 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
501 * a new device structure for the device. Call usbi_alloc_device() to
502 * obtain a new libusb_device structure with reference count 1. Populate
503 * the bus_number and device_address attributes of the new device, and
504 * perform any other internal backend initialization you need to do. At
505 * this point, you should be ready to provide device descriptors and so
506 * on through the get_*_descriptor functions. Finally, call
507 * usbi_sanitize_device() to perform some final sanity checks on the
508 * device. Assuming all of the above succeeded, we can now continue.
509 * If any of the above failed, remember to unreference the device that
510 * was returned by usbi_alloc_device().
512 * At this stage we have a populated libusb_device structure (either one
513 * that was found earlier, or one that we have just allocated and
514 * populated). This can now be added to the discovered devices list
515 * using discovered_devs_append(). Note that discovered_devs_append()
516 * may reallocate the list, returning a new location for it, and also
517 * note that reallocation can fail. Your backend should handle these
518 * error conditions appropriately.
520 * This function should not generate any bus I/O and should not block.
521 * If I/O is required (e.g. reading the active configuration value), it is
522 * OK to ignore these suggestions :)
524 * This function is executed when the user wishes to retrieve a list
525 * of USB devices connected to the system.
527 * Return 0 on success, or a LIBUSB_ERROR code on failure.
529 int (*get_device_list)(struct libusb_context *ctx,
530 struct discovered_devs **discdevs);
532 /* Open a device for I/O and other USB operations. The device handle
533 * is preallocated for you, you can retrieve the device in question
534 * through handle->dev.
536 * Your backend should allocate any internal resources required for I/O
537 * and other operations so that those operations can happen (hopefully)
538 * without hiccup. This is also a good place to inform libusbx that it
539 * should monitor certain file descriptors related to this device -
540 * see the usbi_add_pollfd() function.
542 * This function should not generate any bus I/O and should not block.
544 * This function is called when the user attempts to obtain a device
545 * handle for a device.
549 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
550 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
552 * - another LIBUSB_ERROR code on other failure
554 * Do not worry about freeing the handle on failed open, the upper layers
557 int (*open)(struct libusb_device_handle *handle);
559 /* Close a device such that the handle cannot be used again. Your backend
560 * should destroy any resources that were allocated in the open path.
561 * This may also be a good place to call usbi_remove_pollfd() to inform
562 * libusbx of any file descriptors associated with this device that should
563 * no longer be monitored.
565 * This function is called when the user closes a device handle.
567 void (*close)(struct libusb_device_handle *handle);
569 /* Retrieve the device descriptor from a device.
571 * The descriptor should be retrieved from memory, NOT via bus I/O to the
572 * device. This means that you may have to cache it in a private structure
573 * during get_device_list enumeration. Alternatively, you may be able
574 * to retrieve it from a kernel interface (some Linux setups can do this)
575 * still without generating bus I/O.
577 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
578 * buffer, which is guaranteed to be big enough.
580 * This function is called when sanity-checking a device before adding
581 * it to the list of discovered devices, and also when the user requests
582 * to read the device descriptor.
584 * This function is expected to return the descriptor in bus-endian format
585 * (LE). If it returns the multi-byte values in host-endian format,
586 * set the host_endian output parameter to "1".
588 * Return 0 on success or a LIBUSB_ERROR code on failure.
590 int (*get_device_descriptor)(struct libusb_device *device,
591 unsigned char *buffer, int *host_endian);
593 /* Get the ACTIVE configuration descriptor for a device.
595 * The descriptor should be retrieved from memory, NOT via bus I/O to the
596 * device. This means that you may have to cache it in a private structure
597 * during get_device_list enumeration. You may also have to keep track
598 * of which configuration is active when the user changes it.
600 * This function is expected to write len bytes of data into buffer, which
601 * is guaranteed to be big enough. If you can only do a partial write,
602 * return an error code.
604 * This function is expected to return the descriptor in bus-endian format
605 * (LE). If it returns the multi-byte values in host-endian format,
606 * set the host_endian output parameter to "1".
610 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
611 * - another LIBUSB_ERROR code on other failure
613 int (*get_active_config_descriptor)(struct libusb_device *device,
614 unsigned char *buffer, size_t len, int *host_endian);
616 /* Get a specific configuration descriptor for a device.
618 * The descriptor should be retrieved from memory, NOT via bus I/O to the
619 * device. This means that you may have to cache it in a private structure
620 * during get_device_list enumeration.
622 * The requested descriptor is expressed as a zero-based index (i.e. 0
623 * indicates that we are requesting the first descriptor). The index does
624 * not (necessarily) equal the bConfigurationValue of the configuration
627 * This function is expected to write len bytes of data into buffer, which
628 * is guaranteed to be big enough. If you can only do a partial write,
629 * return an error code.
631 * This function is expected to return the descriptor in bus-endian format
632 * (LE). If it returns the multi-byte values in host-endian format,
633 * set the host_endian output parameter to "1".
635 * Return 0 on success or a LIBUSB_ERROR code on failure.
637 int (*get_config_descriptor)(struct libusb_device *device,
638 uint8_t config_index, unsigned char *buffer, size_t len,
641 /* Get the bConfigurationValue for the active configuration for a device.
642 * Optional. This should only be implemented if you can retrieve it from
643 * cache (don't generate I/O).
645 * If you cannot retrieve this from cache, either do not implement this
646 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
647 * libusbx to retrieve the information through a standard control transfer.
649 * This function must be non-blocking.
652 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
654 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
656 * - another LIBUSB_ERROR code on other failure.
658 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
660 /* Set the active configuration for a device.
662 * A configuration value of -1 should put the device in unconfigured state.
664 * This function can block.
668 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
669 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
670 * configuration cannot be changed)
671 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
673 * - another LIBUSB_ERROR code on other failure.
675 int (*set_configuration)(struct libusb_device_handle *handle, int config);
677 /* Claim an interface. When claimed, the application can then perform
678 * I/O to an interface's endpoints.
680 * This function should not generate any bus I/O and should not block.
681 * Interface claiming is a logical operation that simply ensures that
682 * no other drivers/applications are using the interface, and after
683 * claiming, no other drivers/applicatiosn can use the interface because
688 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
689 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
690 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
692 * - another LIBUSB_ERROR code on other failure
694 int (*claim_interface)(struct libusb_device_handle *handle, int interface_number);
696 /* Release a previously claimed interface.
698 * This function should also generate a SET_INTERFACE control request,
699 * resetting the alternate setting of that interface to 0. It's OK for
700 * this function to block as a result.
702 * You will only ever be asked to release an interface which was
703 * successfully claimed earlier.
707 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
709 * - another LIBUSB_ERROR code on other failure
711 int (*release_interface)(struct libusb_device_handle *handle, int interface_number);
713 /* Set the alternate setting for an interface.
715 * You will only ever be asked to set the alternate setting for an
716 * interface which was successfully claimed earlier.
718 * It's OK for this function to block.
722 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
723 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
725 * - another LIBUSB_ERROR code on other failure
727 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
728 int interface_number, int altsetting);
730 /* Clear a halt/stall condition on an endpoint.
732 * It's OK for this function to block.
736 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
737 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
739 * - another LIBUSB_ERROR code on other failure
741 int (*clear_halt)(struct libusb_device_handle *handle,
742 unsigned char endpoint);
744 /* Perform a USB port reset to reinitialize a device.
746 * If possible, the handle should still be usable after the reset
747 * completes, assuming that the device descriptors did not change during
748 * reset and all previous interface state can be restored.
750 * If something changes, or you cannot easily locate/verify the resetted
751 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
752 * to close the old handle and re-enumerate the device.
756 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
757 * has been disconnected since it was opened
758 * - another LIBUSB_ERROR code on other failure
760 int (*reset_device)(struct libusb_device_handle *handle);
762 /* Determine if a kernel driver is active on an interface. Optional.
764 * The presence of a kernel driver on an interface indicates that any
765 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
768 * - 0 if no driver is active
769 * - 1 if a driver is active
770 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
772 * - another LIBUSB_ERROR code on other failure
774 int (*kernel_driver_active)(struct libusb_device_handle *handle,
775 int interface_number);
777 /* Detach a kernel driver from an interface. Optional.
779 * After detaching a kernel driver, the interface should be available
784 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
785 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
786 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
788 * - another LIBUSB_ERROR code on other failure
790 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
791 int interface_number);
793 /* Attach a kernel driver to an interface. Optional.
795 * Reattach a kernel driver to the device.
799 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
800 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
801 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
803 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
804 * preventing reattachment
805 * - another LIBUSB_ERROR code on other failure
807 int (*attach_kernel_driver)(struct libusb_device_handle *handle,
808 int interface_number);
810 /* Destroy a device. Optional.
812 * This function is called when the last reference to a device is
813 * destroyed. It should free any resources allocated in the get_device_list
816 void (*destroy_device)(struct libusb_device *dev);
818 /* Submit a transfer. Your implementation should take the transfer,
819 * morph it into whatever form your platform requires, and submit it
822 * This function must not block.
826 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
827 * - another LIBUSB_ERROR code on other failure
829 int (*submit_transfer)(struct usbi_transfer *itransfer);
831 /* Cancel a previously submitted transfer.
833 * This function must not block. The transfer cancellation must complete
834 * later, resulting in a call to usbi_handle_transfer_cancellation()
835 * from the context of handle_events.
837 int (*cancel_transfer)(struct usbi_transfer *itransfer);
839 /* Clear a transfer as if it has completed or cancelled, but do not
840 * report any completion/cancellation to the library. You should free
841 * all private data from the transfer as if you were just about to report
842 * completion or cancellation.
844 * This function might seem a bit out of place. It is used when libusbx
845 * detects a disconnected device - it calls this function for all pending
846 * transfers before reporting completion (with the disconnect code) to
847 * the user. Maybe we can improve upon this internal interface in future.
849 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
851 /* Handle any pending events. This involves monitoring any active
852 * transfers and processing their completion or cancellation.
854 * The function is passed an array of pollfd structures (size nfds)
855 * as a result of the poll() system call. The num_ready parameter
856 * indicates the number of file descriptors that have reported events
857 * (i.e. the poll() return value). This should be enough information
858 * for you to determine which actions need to be taken on the currently
861 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
862 * For completed transfers, call usbi_handle_transfer_completion().
863 * For control/bulk/interrupt transfers, populate the "transferred"
864 * element of the appropriate usbi_transfer structure before calling the
865 * above functions. For isochronous transfers, populate the status and
866 * transferred fields of the iso packet descriptors of the transfer.
868 * This function should also be able to detect disconnection of the
869 * device, reporting that situation with usbi_handle_disconnect().
871 * When processing an event related to a transfer, you probably want to
872 * take usbi_transfer.lock to prevent races. See the documentation for
873 * the usbi_transfer structure.
875 * Return 0 on success, or a LIBUSB_ERROR code on failure.
877 int (*handle_events)(struct libusb_context *ctx,
878 struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
880 /* Get time from specified clock. At least two clocks must be implemented
881 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
883 Description of clocks:
884 USBI_CLOCK_REALTIME : clock returns time since system epoch.
885 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
888 int (*clock_gettime)(int clkid, struct timespec *tp);
890 #ifdef USBI_TIMERFD_AVAILABLE
891 /* clock ID of the clock that should be used for timerfd */
892 clockid_t (*get_timerfd_clockid)(void);
895 /* Number of bytes to reserve for per-device private backend data.
896 * This private data area is accessible through the "os_priv" field of
897 * struct libusb_device. */
898 size_t device_priv_size;
900 /* Number of bytes to reserve for per-handle private backend data.
901 * This private data area is accessible through the "os_priv" field of
902 * struct libusb_device. */
903 size_t device_handle_priv_size;
905 /* Number of bytes to reserve for per-transfer private backend data.
906 * This private data area is accessible by calling
907 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
909 size_t transfer_priv_size;
911 /* Mumber of additional bytes for os_priv for each iso packet.
912 * Can your backend use this? */
913 /* FIXME: linux can't use this any more. if other OS's cannot either,
914 * then remove this */
915 size_t add_iso_packet_size;
918 extern const struct usbi_os_backend * const usbi_backend;
920 extern const struct usbi_os_backend linux_usbfs_backend;
921 extern const struct usbi_os_backend darwin_backend;
922 extern const struct usbi_os_backend openbsd_backend;
923 extern const struct usbi_os_backend windows_backend;
924 extern const struct usbi_os_backend wince_backend;
926 extern struct list_head active_contexts_list;
927 extern usbi_mutex_static_t active_contexts_lock;