2 * Internal header for libusb
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
43 #include <android/log.h>
46 /* Attribute to ensure that a structure member is aligned to a natural
47 * pointer alignment. Used for os_priv member. */
50 #define PTR_ALIGNED __declspec(align(8))
52 #define PTR_ALIGNED __declspec(align(4))
54 #elif defined(__GNUC__)
55 #define PTR_ALIGNED __attribute__((aligned(sizeof(void *))))
60 /* Inside the libusb code, mark all public functions as follows:
61 * return_type API_EXPORTED function_name(params) { ... }
62 * But if the function returns a pointer, mark it as follows:
63 * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... }
64 * In the libusb public header, mark all declarations as:
65 * return_type LIBUSB_CALL function_name(params);
67 #define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY
73 #define DEVICE_DESC_LENGTH 18
75 #define USB_MAXENDPOINTS 32
76 #define USB_MAXINTERFACES 32
77 #define USB_MAXCONFIG 8
79 /* Backend specific capabilities */
80 #define USBI_CAP_HAS_HID_ACCESS 0x00010000
81 #define USBI_CAP_SUPPORTS_DETACH_KERNEL_DRIVER 0x00020000
83 /* Maximum number of bytes in a log line */
84 #define USBI_MAX_LOG_LEN 1024
85 /* Terminator for log lines */
86 #define USBI_LOG_LINE_END "\n"
88 /* The following is used to silence warnings for unused variables */
89 #define UNUSED(var) do { (void)(var); } while(0)
91 #if !defined(ARRAYSIZE)
92 #define ARRAYSIZE(array) (sizeof(array) / sizeof(array[0]))
96 struct list_head *prev, *next;
99 /* Get an entry from the list
100 * ptr - the address of this list_head element in "type"
101 * type - the data type that contains "member"
102 * member - the list_head element in "type"
104 #define list_entry(ptr, type, member) \
105 ((type *)((uintptr_t)(ptr) - (uintptr_t)offsetof(type, member)))
107 #define list_first_entry(ptr, type, member) \
108 list_entry((ptr)->next, type, member)
110 /* Get each entry from a list
111 * pos - A structure pointer has a "member" element
113 * member - the list_head element in "pos"
114 * type - the type of the first parameter
116 #define list_for_each_entry(pos, head, member, type) \
117 for (pos = list_entry((head)->next, type, member); \
118 &pos->member != (head); \
119 pos = list_entry(pos->member.next, type, member))
121 #define list_for_each_entry_safe(pos, n, head, member, type) \
122 for (pos = list_entry((head)->next, type, member), \
123 n = list_entry(pos->member.next, type, member); \
124 &pos->member != (head); \
125 pos = n, n = list_entry(n->member.next, type, member))
127 #define list_empty(entry) ((entry)->next == (entry))
129 static inline void list_init(struct list_head *entry)
131 entry->prev = entry->next = entry;
134 static inline void list_add(struct list_head *entry, struct list_head *head)
136 entry->next = head->next;
139 head->next->prev = entry;
143 static inline void list_add_tail(struct list_head *entry,
144 struct list_head *head)
147 entry->prev = head->prev;
149 head->prev->next = entry;
153 static inline void list_del(struct list_head *entry)
155 entry->next->prev = entry->prev;
156 entry->prev->next = entry->next;
157 entry->next = entry->prev = NULL;
160 static inline void list_cut(struct list_head *list, struct list_head *head)
162 if (list_empty(head))
165 list->next = head->next;
166 list->next->prev = list;
167 list->prev = head->prev;
168 list->prev->next = list;
173 static inline void *usbi_reallocf(void *ptr, size_t size)
175 void *ret = realloc(ptr, size);
181 #define container_of(ptr, type, member) ({ \
182 const typeof( ((type *)0)->member ) *mptr = (ptr); \
183 (type *)( (char *)mptr - offsetof(type,member) );})
186 #define CLAMP(val, min, max) ((val) < (min) ? (min) : ((val) > (max) ? (max) : (val)))
189 #define MIN(a, b) ((a) < (b) ? (a) : (b))
192 #define MAX(a, b) ((a) > (b) ? (a) : (b))
195 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
197 #if defined(_WIN32) || defined(__CYGWIN__) || defined(_WIN32_WCE)
198 #define TIMEVAL_TV_SEC_TYPE long
200 #define TIMEVAL_TV_SEC_TYPE time_t
203 /* Some platforms don't have this define */
204 #ifndef TIMESPEC_TO_TIMEVAL
205 #define TIMESPEC_TO_TIMEVAL(tv, ts) \
207 (tv)->tv_sec = (TIMEVAL_TV_SEC_TYPE) (ts)->tv_sec; \
208 (tv)->tv_usec = (ts)->tv_nsec / 1000; \
212 #ifdef ENABLE_LOGGING
214 #if defined(_MSC_VER) && (_MSC_VER < 1900)
215 #define snprintf usbi_snprintf
216 #define vsnprintf usbi_vsnprintf
217 int usbi_snprintf(char *dst, size_t size, const char *format, ...);
218 int usbi_vsnprintf(char *dst, size_t size, const char *format, va_list ap);
219 #define LIBUSB_PRINTF_WIN32
220 #endif /* defined(_MSC_VER) && (_MSC_VER < 1900) */
222 void usbi_log(struct libusb_context *ctx, enum libusb_log_level level,
223 const char *function, const char *format, ...);
225 void usbi_log_v(struct libusb_context *ctx, enum libusb_log_level level,
226 const char *function, const char *format, va_list args);
228 #if !defined(_MSC_VER) || (_MSC_VER >= 1400)
230 #define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__)
232 #define usbi_err(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_ERROR, __VA_ARGS__)
233 #define usbi_warn(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_WARNING, __VA_ARGS__)
234 #define usbi_info(ctx, ...) _usbi_log(ctx, LIBUSB_LOG_LEVEL_INFO, __VA_ARGS__)
235 //#define usbi_dbg(...) _usbi_log(NULL, LIBUSB_LOG_LEVEL_DEBUG, __VA_ARGS__)
236 #define usbi_dbg(...) __android_log_print(ANDROID_LOG_ERROR, "libusb", __VA_ARGS__)
238 #else /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */
240 #define LOG_BODY(ctxt, level) \
243 va_start(args, format); \
244 usbi_log_v(ctxt, level, "", format, args); \
248 static inline void usbi_err(struct libusb_context *ctx, const char *format, ...)
249 LOG_BODY(ctx, LIBUSB_LOG_LEVEL_ERROR)
250 static inline void usbi_warn(struct libusb_context *ctx, const char *format, ...)
251 LOG_BODY(ctx, LIBUSB_LOG_LEVEL_WARNING)
252 static inline void usbi_info(struct libusb_context *ctx, const char *format, ...)
253 LOG_BODY(ctx, LIBUSB_LOG_LEVEL_INFO)
254 static inline void usbi_dbg(const char *format, ...)
255 LOG_BODY(NULL, LIBUSB_LOG_LEVEL_DEBUG)
257 #endif /* !defined(_MSC_VER) || (_MSC_VER >= 1400) */
259 #else /* ENABLE_LOGGING */
261 #define usbi_err(ctx, ...) do { (void)ctx; } while (0)
262 #define usbi_warn(ctx, ...) do { (void)ctx; } while (0)
263 #define usbi_info(ctx, ...) do { (void)ctx; } while (0)
264 #define usbi_dbg(...) do {} while (0)
266 #endif /* ENABLE_LOGGING */
268 #define USBI_GET_CONTEXT(ctx) \
271 (ctx) = usbi_default_context; \
274 #define DEVICE_CTX(dev) ((dev)->ctx)
275 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
276 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
277 #define ITRANSFER_CTX(transfer) \
278 (TRANSFER_CTX(USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
280 #define IS_EPIN(ep) (0 != ((ep) & LIBUSB_ENDPOINT_IN))
281 #define IS_EPOUT(ep) (!IS_EPIN(ep))
282 #define IS_XFERIN(xfer) (0 != ((xfer)->endpoint & LIBUSB_ENDPOINT_IN))
283 #define IS_XFEROUT(xfer) (!IS_XFERIN(xfer))
285 /* Internal abstraction for thread synchronization */
286 #if defined(THREADS_POSIX)
287 #include "os/threads_posix.h"
288 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
289 #include "os/threads_windows.h"
292 extern struct libusb_context *usbi_default_context;
294 /* Forward declaration for use in context (fully defined inside poll abstraction) */
297 struct libusb_context {
298 #if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
299 enum libusb_log_level debug;
303 /* internal event pipe, used for signalling occurrence of an internal event. */
306 struct list_head usb_devs;
307 usbi_mutex_t usb_devs_lock;
309 /* A list of open handles. Backends are free to traverse this if required.
311 struct list_head open_devs;
312 usbi_mutex_t open_devs_lock;
314 /* A list of registered hotplug callbacks */
315 struct list_head hotplug_cbs;
316 libusb_hotplug_callback_handle next_hotplug_cb_handle;
317 usbi_mutex_t hotplug_cbs_lock;
319 /* this is a list of in-flight transfer handles, sorted by timeout
320 * expiration. URBs to timeout the soonest are placed at the beginning of
321 * the list, URBs that will time out later are placed after, and urbs with
322 * infinite timeout are always placed at the very end. */
323 struct list_head flying_transfers;
324 /* Note paths taking both this and usbi_transfer->lock must always
325 * take this lock first */
326 usbi_mutex_t flying_transfers_lock;
328 /* user callbacks for pollfd changes */
329 libusb_pollfd_added_cb fd_added_cb;
330 libusb_pollfd_removed_cb fd_removed_cb;
331 void *fd_cb_user_data;
333 /* ensures that only one thread is handling events at any one time */
334 usbi_mutex_t events_lock;
336 /* used to see if there is an active thread doing event handling */
337 int event_handler_active;
339 /* A thread-local storage key to track which thread is performing event
341 usbi_tls_key_t event_handling_key;
343 /* used to wait for event completion in threads other than the one that is
345 usbi_mutex_t event_waiters_lock;
346 usbi_cond_t event_waiters_cond;
348 /* A lock to protect internal context event data. */
349 usbi_mutex_t event_data_lock;
351 /* A bitmask of flags that are set to indicate specific events that need to
352 * be handled. Protected by event_data_lock. */
353 unsigned int event_flags;
355 /* A counter that is set when we want to interrupt and prevent event handling,
356 * in order to safely close a device. Protected by event_data_lock. */
357 unsigned int device_close;
359 /* list and count of poll fds and an array of poll fd structures that is
360 * (re)allocated as necessary prior to polling. Protected by event_data_lock. */
361 struct list_head ipollfds;
362 struct pollfd *pollfds;
363 POLL_NFDS_TYPE pollfds_cnt;
365 /* A list of pending hotplug messages. Protected by event_data_lock. */
366 struct list_head hotplug_msgs;
368 /* A list of pending completed transfers. Protected by event_data_lock. */
369 struct list_head completed_transfers;
371 #ifdef USBI_TIMERFD_AVAILABLE
372 /* used for timeout handling, if supported by OS.
373 * this timerfd is maintained to trigger on the next pending timeout */
377 struct list_head list;
379 PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
382 enum usbi_event_flags {
383 /* The list of pollfds has been modified */
384 USBI_EVENT_POLLFDS_MODIFIED = 1 << 0,
386 /* The user has interrupted the event handler */
387 USBI_EVENT_USER_INTERRUPT = 1 << 1,
389 /* A hotplug callback deregistration is pending */
390 USBI_EVENT_HOTPLUG_CB_DEREGISTERED = 1 << 2,
393 /* Macros for managing event handling state */
394 #define usbi_handling_events(ctx) \
395 (usbi_tls_key_get((ctx)->event_handling_key) != NULL)
397 #define usbi_start_event_handling(ctx) \
398 usbi_tls_key_set((ctx)->event_handling_key, ctx)
400 #define usbi_end_event_handling(ctx) \
401 usbi_tls_key_set((ctx)->event_handling_key, NULL)
403 /* Update the following macro if new event sources are added */
404 #define usbi_pending_events(ctx) \
405 ((ctx)->event_flags || (ctx)->device_close \
406 || !list_empty(&(ctx)->hotplug_msgs) || !list_empty(&(ctx)->completed_transfers))
408 #ifdef USBI_TIMERFD_AVAILABLE
409 #define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0)
411 #define usbi_using_timerfd(ctx) (0)
414 struct libusb_device {
415 /* lock protects refcnt, everything else is finalized at initialization
420 struct libusb_context *ctx;
424 struct libusb_device* parent_dev;
425 uint8_t device_address;
426 uint8_t num_configurations;
427 enum libusb_speed speed;
429 struct list_head list;
430 unsigned long session_data;
432 struct libusb_device_descriptor device_descriptor;
435 PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
438 struct libusb_device_handle {
439 /* lock protects claimed_interfaces */
441 unsigned long claimed_interfaces;
443 struct list_head list;
444 struct libusb_device *dev;
445 int auto_detach_kernel_driver;
447 PTR_ALIGNED unsigned char os_priv[ZERO_SIZED_ARRAY];
451 USBI_CLOCK_MONOTONIC,
455 /* in-memory transfer layout:
457 * 1. struct usbi_transfer
458 * 2. struct libusb_transfer (which includes iso packets) [variable size]
459 * 3. os private data [variable size]
461 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
462 * appropriate number of bytes.
463 * the usbi_transfer includes the number of allocated packets, so you can
464 * determine the size of the transfer and hence the start and length of the
468 struct usbi_transfer {
470 struct list_head list;
471 struct list_head completed_list;
472 struct timeval timeout;
475 uint8_t state_flags; /* Protected by usbi_transfer->lock */
476 uint8_t timeout_flags; /* Protected by the flying_stransfers_lock */
478 /* this lock is held during libusb_submit_transfer() and
479 * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate
480 * cancellation, submission-during-cancellation, etc). the OS backend
481 * should also take this lock in the handle_events path, to prevent the user
482 * cancelling the transfer from another thread while you are processing
483 * its completion (presumably there would be races within your OS backend
484 * if this were possible).
485 * Note paths taking both this and the flying_transfers_lock must
486 * always take the flying_transfers_lock first */
490 enum usbi_transfer_state_flags {
491 /* Transfer successfully submitted by backend */
492 USBI_TRANSFER_IN_FLIGHT = 1 << 0,
494 /* Cancellation was requested via libusb_cancel_transfer() */
495 USBI_TRANSFER_CANCELLING = 1 << 1,
497 /* Operation on the transfer failed because the device disappeared */
498 USBI_TRANSFER_DEVICE_DISAPPEARED = 1 << 2,
501 enum usbi_transfer_timeout_flags {
502 /* Set by backend submit_transfer() if the OS handles timeout */
503 USBI_TRANSFER_OS_HANDLES_TIMEOUT = 1 << 0,
505 /* The transfer timeout has been handled */
506 USBI_TRANSFER_TIMEOUT_HANDLED = 1 << 1,
508 /* The transfer timeout was successfully processed */
509 USBI_TRANSFER_TIMED_OUT = 1 << 2,
512 #define USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
513 ((struct libusb_transfer *)(((unsigned char *)(transfer)) \
514 + sizeof(struct usbi_transfer)))
515 #define LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
516 ((struct usbi_transfer *)(((unsigned char *)(transfer)) \
517 - sizeof(struct usbi_transfer)))
519 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
521 return ((unsigned char *)transfer) + sizeof(struct usbi_transfer)
522 + sizeof(struct libusb_transfer)
523 + (transfer->num_iso_packets
524 * sizeof(struct libusb_iso_packet_descriptor));
529 /* All standard descriptors have these 2 fields in common */
530 struct usb_descriptor_header {
532 uint8_t bDescriptorType;
535 /* shared data and functions */
537 int usbi_io_init(struct libusb_context *ctx);
538 void usbi_io_exit(struct libusb_context *ctx);
540 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
541 unsigned long session_id);
542 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
543 unsigned long session_id);
544 int usbi_sanitize_device(struct libusb_device *dev);
545 void usbi_handle_disconnect(struct libusb_device_handle *dev_handle);
547 int usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
548 enum libusb_transfer_status status);
549 int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
550 void usbi_signal_transfer_completion(struct usbi_transfer *transfer);
552 int usbi_parse_descriptor(const unsigned char *source, const char *descriptor,
553 void *dest, int host_endian);
554 int usbi_device_cache_descriptor(libusb_device *dev);
555 int usbi_get_config_index_by_value(struct libusb_device *dev,
556 uint8_t bConfigurationValue, int *idx);
558 void usbi_connect_device (struct libusb_device *dev);
559 void usbi_disconnect_device (struct libusb_device *dev);
561 int usbi_signal_event(struct libusb_context *ctx);
562 int usbi_clear_event(struct libusb_context *ctx);
564 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
565 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD) || defined(OS_NETBSD) ||\
566 defined(OS_HAIKU) || defined(OS_SUNOS)
568 #include "os/poll_posix.h"
569 #elif defined(OS_WINDOWS) || defined(OS_WINCE)
570 #include "os/poll_windows.h"
574 /* must come first */
575 struct libusb_pollfd pollfd;
577 struct list_head list;
580 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
581 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
583 /* device discovery */
585 /* we traverse usbfs without knowing how many devices we are going to find.
586 * so we create this discovered_devs model which is similar to a linked-list
587 * which grows when required. it can be freed once discovery has completed,
588 * eliminating the need for a list node in the libusb_device structure
590 struct discovered_devs {
593 struct libusb_device *devices[ZERO_SIZED_ARRAY];
596 struct discovered_devs *discovered_devs_append(
597 struct discovered_devs *discdevs, struct libusb_device *dev);
601 /* This is the interface that OS backends need to implement.
602 * All fields are mandatory, except ones explicitly noted as optional. */
603 struct usbi_os_backend {
604 /* A human-readable name for your backend, e.g. "Linux usbfs" */
607 /* Binary mask for backend specific capabilities */
610 /* Perform initialization of your backend. You might use this function
611 * to determine specific capabilities of the system, allocate required
612 * data structures for later, etc.
614 * This function is called when a libusb user initializes the library
617 * Return 0 on success, or a LIBUSB_ERROR code on failure.
619 int (*init)(struct libusb_context *ctx);
621 /* Deinitialization. Optional. This function should destroy anything
622 * that was set up by init.
624 * This function is called when the user deinitializes the library.
626 void (*exit)(struct libusb_context *ctx);
628 /* Set a backend-specific option. Optional.
630 * This function is called when the user calls libusb_set_option() and
631 * the option is not handled by the core library.
633 * Return 0 on success, or a LIBUSB_ERROR code on failure.
635 int (*set_option)(struct libusb_context *ctx, enum libusb_option option,
638 /* Enumerate all the USB devices on the system, returning them in a list
639 * of discovered devices.
641 * Your implementation should enumerate all devices on the system,
642 * regardless of whether they have been seen before or not.
644 * When you have found a device, compute a session ID for it. The session
645 * ID should uniquely represent that particular device for that particular
646 * connection session since boot (i.e. if you disconnect and reconnect a
647 * device immediately after, it should be assigned a different session ID).
648 * If your OS cannot provide a unique session ID as described above,
649 * presenting a session ID of (bus_number << 8 | device_address) should
650 * be sufficient. Bus numbers and device addresses wrap and get reused,
651 * but that is an unlikely case.
653 * After computing a session ID for a device, call
654 * usbi_get_device_by_session_id(). This function checks if libusb already
655 * knows about the device, and if so, it provides you with a reference
656 * to a libusb_device structure for it.
658 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
659 * a new device structure for the device. Call usbi_alloc_device() to
660 * obtain a new libusb_device structure with reference count 1. Populate
661 * the bus_number and device_address attributes of the new device, and
662 * perform any other internal backend initialization you need to do. At
663 * this point, you should be ready to provide device descriptors and so
664 * on through the get_*_descriptor functions. Finally, call
665 * usbi_sanitize_device() to perform some final sanity checks on the
666 * device. Assuming all of the above succeeded, we can now continue.
667 * If any of the above failed, remember to unreference the device that
668 * was returned by usbi_alloc_device().
670 * At this stage we have a populated libusb_device structure (either one
671 * that was found earlier, or one that we have just allocated and
672 * populated). This can now be added to the discovered devices list
673 * using discovered_devs_append(). Note that discovered_devs_append()
674 * may reallocate the list, returning a new location for it, and also
675 * note that reallocation can fail. Your backend should handle these
676 * error conditions appropriately.
678 * This function should not generate any bus I/O and should not block.
679 * If I/O is required (e.g. reading the active configuration value), it is
680 * OK to ignore these suggestions :)
682 * This function is executed when the user wishes to retrieve a list
683 * of USB devices connected to the system.
685 * If the backend has hotplug support, this function is not used!
687 * Return 0 on success, or a LIBUSB_ERROR code on failure.
689 int (*get_device_list)(struct libusb_context *ctx,
690 struct discovered_devs **discdevs);
692 /* Apps which were written before hotplug support, may listen for
693 * hotplug events on their own and call libusb_get_device_list on
694 * device addition. In this case libusb_get_device_list will likely
695 * return a list without the new device in there, as the hotplug
696 * event thread will still be busy enumerating the device, which may
697 * take a while, or may not even have seen the event yet.
699 * To avoid this libusb_get_device_list will call this optional
700 * function for backends with hotplug support before copying
701 * ctx->usb_devs to the user. In this function the backend should
702 * ensure any pending hotplug events are fully processed before
705 * Optional, should be implemented by backends with hotplug support.
707 void (*hotplug_poll)(void);
709 /* Open a device for I/O and other USB operations. The device handle
710 * is preallocated for you, you can retrieve the device in question
711 * through handle->dev.
713 * Your backend should allocate any internal resources required for I/O
714 * and other operations so that those operations can happen (hopefully)
715 * without hiccup. This is also a good place to inform libusb that it
716 * should monitor certain file descriptors related to this device -
717 * see the usbi_add_pollfd() function.
719 * This function should not generate any bus I/O and should not block.
721 * This function is called when the user attempts to obtain a device
722 * handle for a device.
726 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
727 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
729 * - another LIBUSB_ERROR code on other failure
731 * Do not worry about freeing the handle on failed open, the upper layers
734 int (*open)(struct libusb_device_handle *dev_handle);
736 /* Close a device such that the handle cannot be used again. Your backend
737 * should destroy any resources that were allocated in the open path.
738 * This may also be a good place to call usbi_remove_pollfd() to inform
739 * libusb of any file descriptors associated with this device that should
740 * no longer be monitored.
742 * This function is called when the user closes a device handle.
744 void (*close)(struct libusb_device_handle *dev_handle);
746 /* Retrieve the device descriptor from a device.
748 * The descriptor should be retrieved from memory, NOT via bus I/O to the
749 * device. This means that you may have to cache it in a private structure
750 * during get_device_list enumeration. Alternatively, you may be able
751 * to retrieve it from a kernel interface (some Linux setups can do this)
752 * still without generating bus I/O.
754 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
755 * buffer, which is guaranteed to be big enough.
757 * This function is called when sanity-checking a device before adding
758 * it to the list of discovered devices, and also when the user requests
759 * to read the device descriptor.
761 * This function is expected to return the descriptor in bus-endian format
762 * (LE). If it returns the multi-byte values in host-endian format,
763 * set the host_endian output parameter to "1".
765 * Return 0 on success or a LIBUSB_ERROR code on failure.
767 int (*get_device_descriptor)(struct libusb_device *device,
768 unsigned char *buffer, int *host_endian);
770 /* Get the ACTIVE configuration descriptor for a device.
772 * The descriptor should be retrieved from memory, NOT via bus I/O to the
773 * device. This means that you may have to cache it in a private structure
774 * during get_device_list enumeration. You may also have to keep track
775 * of which configuration is active when the user changes it.
777 * This function is expected to write len bytes of data into buffer, which
778 * is guaranteed to be big enough. If you can only do a partial write,
779 * return an error code.
781 * This function is expected to return the descriptor in bus-endian format
782 * (LE). If it returns the multi-byte values in host-endian format,
783 * set the host_endian output parameter to "1".
787 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
788 * - another LIBUSB_ERROR code on other failure
790 int (*get_active_config_descriptor)(struct libusb_device *device,
791 unsigned char *buffer, size_t len, int *host_endian);
793 /* Get a specific configuration descriptor for a device.
795 * The descriptor should be retrieved from memory, NOT via bus I/O to the
796 * device. This means that you may have to cache it in a private structure
797 * during get_device_list enumeration.
799 * The requested descriptor is expressed as a zero-based index (i.e. 0
800 * indicates that we are requesting the first descriptor). The index does
801 * not (necessarily) equal the bConfigurationValue of the configuration
804 * This function is expected to write len bytes of data into buffer, which
805 * is guaranteed to be big enough. If you can only do a partial write,
806 * return an error code.
808 * This function is expected to return the descriptor in bus-endian format
809 * (LE). If it returns the multi-byte values in host-endian format,
810 * set the host_endian output parameter to "1".
812 * Return the length read on success or a LIBUSB_ERROR code on failure.
814 int (*get_config_descriptor)(struct libusb_device *device,
815 uint8_t config_index, unsigned char *buffer, size_t len,
818 /* Like get_config_descriptor but then by bConfigurationValue instead
821 * Optional, if not present the core will call get_config_descriptor
822 * for all configs until it finds the desired bConfigurationValue.
824 * Returns a pointer to the raw-descriptor in *buffer, this memory
825 * is valid as long as device is valid.
827 * Returns the length of the returned raw-descriptor on success,
828 * or a LIBUSB_ERROR code on failure.
830 int (*get_config_descriptor_by_value)(struct libusb_device *device,
831 uint8_t bConfigurationValue, unsigned char **buffer,
834 /* Get the bConfigurationValue for the active configuration for a device.
835 * Optional. This should only be implemented if you can retrieve it from
836 * cache (don't generate I/O).
838 * If you cannot retrieve this from cache, either do not implement this
839 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
840 * libusb to retrieve the information through a standard control transfer.
842 * This function must be non-blocking.
845 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
847 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
849 * - another LIBUSB_ERROR code on other failure.
851 int (*get_configuration)(struct libusb_device_handle *dev_handle, int *config);
853 /* Set the active configuration for a device.
855 * A configuration value of -1 should put the device in unconfigured state.
857 * This function can block.
861 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
862 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
863 * configuration cannot be changed)
864 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
866 * - another LIBUSB_ERROR code on other failure.
868 int (*set_configuration)(struct libusb_device_handle *dev_handle, int config);
870 /* Claim an interface. When claimed, the application can then perform
871 * I/O to an interface's endpoints.
873 * This function should not generate any bus I/O and should not block.
874 * Interface claiming is a logical operation that simply ensures that
875 * no other drivers/applications are using the interface, and after
876 * claiming, no other drivers/applications can use the interface because
881 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
882 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
883 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
885 * - another LIBUSB_ERROR code on other failure
887 int (*claim_interface)(struct libusb_device_handle *dev_handle, int interface_number);
889 /* Release a previously claimed interface.
891 * This function should also generate a SET_INTERFACE control request,
892 * resetting the alternate setting of that interface to 0. It's OK for
893 * this function to block as a result.
895 * You will only ever be asked to release an interface which was
896 * successfully claimed earlier.
900 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
902 * - another LIBUSB_ERROR code on other failure
904 int (*release_interface)(struct libusb_device_handle *dev_handle, int interface_number);
906 /* Set the alternate setting for an interface.
908 * You will only ever be asked to set the alternate setting for an
909 * interface which was successfully claimed earlier.
911 * It's OK for this function to block.
915 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
916 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
918 * - another LIBUSB_ERROR code on other failure
920 int (*set_interface_altsetting)(struct libusb_device_handle *dev_handle,
921 int interface_number, int altsetting);
923 /* Clear a halt/stall condition on an endpoint.
925 * It's OK for this function to block.
929 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
930 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
932 * - another LIBUSB_ERROR code on other failure
934 int (*clear_halt)(struct libusb_device_handle *dev_handle,
935 unsigned char endpoint);
937 /* Perform a USB port reset to reinitialize a device.
939 * If possible, the device handle should still be usable after the reset
940 * completes, assuming that the device descriptors did not change during
941 * reset and all previous interface state can be restored.
943 * If something changes, or you cannot easily locate/verify the resetted
944 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
945 * to close the old handle and re-enumerate the device.
949 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
950 * has been disconnected since it was opened
951 * - another LIBUSB_ERROR code on other failure
953 int (*reset_device)(struct libusb_device_handle *dev_handle);
955 /* Alloc num_streams usb3 bulk streams on the passed in endpoints */
956 int (*alloc_streams)(struct libusb_device_handle *dev_handle,
957 uint32_t num_streams, unsigned char *endpoints, int num_endpoints);
959 /* Free usb3 bulk streams allocated with alloc_streams */
960 int (*free_streams)(struct libusb_device_handle *dev_handle,
961 unsigned char *endpoints, int num_endpoints);
963 /* Allocate persistent DMA memory for the given device, suitable for
964 * zerocopy. May return NULL on failure. Optional to implement.
966 unsigned char *(*dev_mem_alloc)(struct libusb_device_handle *handle,
969 /* Free memory allocated by dev_mem_alloc. */
970 int (*dev_mem_free)(struct libusb_device_handle *handle,
971 unsigned char *buffer, size_t len);
973 /* Determine if a kernel driver is active on an interface. Optional.
975 * The presence of a kernel driver on an interface indicates that any
976 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
979 * - 0 if no driver is active
980 * - 1 if a driver is active
981 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
983 * - another LIBUSB_ERROR code on other failure
985 int (*kernel_driver_active)(struct libusb_device_handle *dev_handle,
986 int interface_number);
988 /* Detach a kernel driver from an interface. Optional.
990 * After detaching a kernel driver, the interface should be available
995 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
996 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
997 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
999 * - another LIBUSB_ERROR code on other failure
1001 int (*detach_kernel_driver)(struct libusb_device_handle *dev_handle,
1002 int interface_number);
1004 /* Attach a kernel driver to an interface. Optional.
1006 * Reattach a kernel driver to the device.
1010 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
1011 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
1012 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
1014 * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface,
1015 * preventing reattachment
1016 * - another LIBUSB_ERROR code on other failure
1018 int (*attach_kernel_driver)(struct libusb_device_handle *dev_handle,
1019 int interface_number);
1021 /* Destroy a device. Optional.
1023 * This function is called when the last reference to a device is
1024 * destroyed. It should free any resources allocated in the get_device_list
1027 void (*destroy_device)(struct libusb_device *dev);
1029 /* Submit a transfer. Your implementation should take the transfer,
1030 * morph it into whatever form your platform requires, and submit it
1033 * This function must not block.
1035 * This function gets called with the flying_transfers_lock locked!
1039 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
1040 * - another LIBUSB_ERROR code on other failure
1042 int (*submit_transfer)(struct usbi_transfer *itransfer);
1044 /* Cancel a previously submitted transfer.
1046 * This function must not block. The transfer cancellation must complete
1047 * later, resulting in a call to usbi_handle_transfer_cancellation()
1048 * from the context of handle_events.
1050 int (*cancel_transfer)(struct usbi_transfer *itransfer);
1052 /* Clear a transfer as if it has completed or cancelled, but do not
1053 * report any completion/cancellation to the library. You should free
1054 * all private data from the transfer as if you were just about to report
1055 * completion or cancellation.
1057 * This function might seem a bit out of place. It is used when libusb
1058 * detects a disconnected device - it calls this function for all pending
1059 * transfers before reporting completion (with the disconnect code) to
1060 * the user. Maybe we can improve upon this internal interface in future.
1062 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
1064 /* Handle any pending events on file descriptors. Optional.
1066 * Provide this function when file descriptors directly indicate device
1067 * or transfer activity. If your backend does not have such file descriptors,
1068 * implement the handle_transfer_completion function below.
1070 * This involves monitoring any active transfers and processing their
1071 * completion or cancellation.
1073 * The function is passed an array of pollfd structures (size nfds)
1074 * as a result of the poll() system call. The num_ready parameter
1075 * indicates the number of file descriptors that have reported events
1076 * (i.e. the poll() return value). This should be enough information
1077 * for you to determine which actions need to be taken on the currently
1080 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
1081 * For completed transfers, call usbi_handle_transfer_completion().
1082 * For control/bulk/interrupt transfers, populate the "transferred"
1083 * element of the appropriate usbi_transfer structure before calling the
1084 * above functions. For isochronous transfers, populate the status and
1085 * transferred fields of the iso packet descriptors of the transfer.
1087 * This function should also be able to detect disconnection of the
1088 * device, reporting that situation with usbi_handle_disconnect().
1090 * When processing an event related to a transfer, you probably want to
1091 * take usbi_transfer.lock to prevent races. See the documentation for
1092 * the usbi_transfer structure.
1094 * Return 0 on success, or a LIBUSB_ERROR code on failure.
1096 int (*handle_events)(struct libusb_context *ctx,
1097 struct pollfd *fds, POLL_NFDS_TYPE nfds, int num_ready);
1099 /* Handle transfer completion. Optional.
1101 * Provide this function when there are no file descriptors available
1102 * that directly indicate device or transfer activity. If your backend does
1103 * have such file descriptors, implement the handle_events function above.
1105 * Your backend must tell the library when a transfer has completed by
1106 * calling usbi_signal_transfer_completion(). You should store any private
1107 * information about the transfer and its completion status in the transfer's
1108 * private backend data.
1110 * During event handling, this function will be called on each transfer for
1111 * which usbi_signal_transfer_completion() was called.
1113 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
1114 * For completed transfers, call usbi_handle_transfer_completion().
1115 * For control/bulk/interrupt transfers, populate the "transferred"
1116 * element of the appropriate usbi_transfer structure before calling the
1117 * above functions. For isochronous transfers, populate the status and
1118 * transferred fields of the iso packet descriptors of the transfer.
1120 * Return 0 on success, or a LIBUSB_ERROR code on failure.
1122 int (*handle_transfer_completion)(struct usbi_transfer *itransfer);
1124 /* Get time from specified clock. At least two clocks must be implemented
1125 by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC.
1127 Description of clocks:
1128 USBI_CLOCK_REALTIME : clock returns time since system epoch.
1129 USBI_CLOCK_MONOTONIC: clock returns time since unspecified start
1130 time (usually boot).
1132 int (*clock_gettime)(int clkid, struct timespec *tp);
1134 #ifdef USBI_TIMERFD_AVAILABLE
1135 /* clock ID of the clock that should be used for timerfd */
1136 clockid_t (*get_timerfd_clockid)(void);
1139 /* Number of bytes to reserve for per-context private backend data.
1140 * This private data area is accessible through the "os_priv" field of
1141 * struct libusb_context. */
1142 size_t context_priv_size;
1144 /* Number of bytes to reserve for per-device private backend data.
1145 * This private data area is accessible through the "os_priv" field of
1146 * struct libusb_device. */
1147 size_t device_priv_size;
1149 /* Number of bytes to reserve for per-handle private backend data.
1150 * This private data area is accessible through the "os_priv" field of
1151 * struct libusb_device. */
1152 size_t device_handle_priv_size;
1154 /* Number of bytes to reserve for per-transfer private backend data.
1155 * This private data area is accessible by calling
1156 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
1158 size_t transfer_priv_size;
1161 extern const struct usbi_os_backend usbi_backend;
1163 extern struct list_head active_contexts_list;
1164 extern usbi_mutex_static_t active_contexts_lock;