2 * Internal header for libusb
3 * Copyright (C) 2007-2008 Daniel Drake <dsd@gentoo.org>
4 * Copyright (c) 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
33 #define DEVICE_DESC_LENGTH 18
35 #define USB_MAXENDPOINTS 32
36 #define USB_MAXINTERFACES 32
37 #define USB_MAXCONFIG 8
40 struct list_head *prev, *next;
43 /* Get an entry from the list
44 * ptr - the address of this list_head element in "type"
45 * type - the data type that contains "member"
46 * member - the list_head element in "type"
48 #define list_entry(ptr, type, member) \
49 ((type *)((char *)(ptr) - (unsigned long)(&((type *)0L)->member)))
51 /* Get each entry from a list
52 * pos - A structure pointer has a "member" element
54 * member - the list_head element in "pos"
56 #define list_for_each_entry(pos, head, member) \
57 for (pos = list_entry((head)->next, typeof(*pos), member); \
58 &pos->member != (head); \
59 pos = list_entry(pos->member.next, typeof(*pos), member))
61 #define list_for_each_entry_safe(pos, n, head, member) \
62 for (pos = list_entry((head)->next, typeof(*pos), member), \
63 n = list_entry(pos->member.next, typeof(*pos), member); \
64 &pos->member != (head); \
65 pos = n, n = list_entry(n->member.next, typeof(*n), member))
67 #define list_empty(entry) ((entry)->next == (entry))
69 static inline void list_init(struct list_head *entry)
71 entry->prev = entry->next = entry;
74 static inline void list_add(struct list_head *entry, struct list_head *head)
76 entry->next = head->next;
79 head->next->prev = entry;
83 static inline void list_add_tail(struct list_head *entry,
84 struct list_head *head)
87 entry->prev = head->prev;
89 head->prev->next = entry;
93 static inline void list_del(struct list_head *entry)
95 entry->next->prev = entry->prev;
96 entry->prev->next = entry->next;
99 #define container_of(ptr, type, member) ({ \
100 const typeof( ((type *)0)->member ) *__mptr = (ptr); \
101 (type *)( (char *)__mptr - offsetof(type,member) );})
103 #define MIN(a, b) ((a) < (b) ? (a) : (b))
104 #define MAX(a, b) ((a) > (b) ? (a) : (b))
106 #define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0)
108 enum usbi_log_level {
115 void usbi_log(struct libusb_context *ctx, enum usbi_log_level,
116 const char *function, const char *format, ...);
118 #ifdef ENABLE_LOGGING
119 #define _usbi_log(ctx, level, fmt...) usbi_log(ctx, level, __FUNCTION__, fmt)
121 #define _usbi_log(ctx, level, fmt...)
124 #ifdef ENABLE_DEBUG_LOGGING
125 #define usbi_dbg(fmt...) _usbi_log(NULL, LOG_LEVEL_DEBUG, fmt)
127 #define usbi_dbg(fmt...)
130 #define usbi_info(ctx, fmt...) _usbi_log(ctx, LOG_LEVEL_INFO, fmt)
131 #define usbi_warn(ctx, fmt...) _usbi_log(ctx, LOG_LEVEL_WARNING, fmt)
132 #define usbi_err(ctx, fmt...) _usbi_log(ctx, LOG_LEVEL_ERROR, fmt)
134 #define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context
135 #define DEVICE_CTX(dev) ((dev)->ctx)
136 #define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev))
137 #define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle))
138 #define ITRANSFER_CTX(transfer) \
139 (TRANSFER_CTX(__USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)))
141 extern struct libusb_context *usbi_default_context;
143 struct libusb_context {
147 struct list_head usb_devs;
148 pthread_mutex_t usb_devs_lock;
150 /* A list of open handles. Backends are free to traverse this if required.
152 struct list_head open_devs;
153 pthread_mutex_t open_devs_lock;
155 /* this is a list of in-flight transfer handles, sorted by timeout
156 * expiration. URBs to timeout the soonest are placed at the beginning of
157 * the list, URBs that will time out later are placed after, and urbs with
158 * infinite timeout are always placed at the very end. */
159 struct list_head flying_transfers;
160 pthread_mutex_t flying_transfers_lock;
162 /* list of poll fd's */
163 struct list_head pollfds;
164 pthread_mutex_t pollfds_lock;
166 /* user callbacks for pollfd changes */
167 libusb_pollfd_added_cb fd_added_cb;
168 libusb_pollfd_removed_cb fd_removed_cb;
169 void *fd_cb_user_data;
171 /* ensures that only one thread is handling events at any one time */
172 pthread_mutex_t events_lock;
174 /* used to see if there is an active thread doing event handling */
175 int event_handler_active;
177 /* used to wait for event completion in threads other than the one that is
179 pthread_mutex_t event_waiters_lock;
180 pthread_cond_t event_waiters_cond;
183 struct libusb_device {
184 /* lock protects refcnt, everything else is finalized at initialization
186 pthread_mutex_t lock;
189 struct libusb_context *ctx;
192 uint8_t device_address;
193 uint8_t num_configurations;
195 struct list_head list;
196 unsigned long session_data;
197 unsigned char os_priv[0];
200 struct libusb_device_handle {
201 /* lock protects claimed_interfaces */
202 pthread_mutex_t lock;
203 unsigned long claimed_interfaces;
205 struct list_head list;
206 struct libusb_device *dev;
207 unsigned char os_priv[0];
210 #define USBI_TRANSFER_TIMED_OUT (1<<0)
212 /* in-memory transfer layout:
214 * 1. struct usbi_transfer
215 * 2. struct libusb_transfer (which includes iso packets) [variable size]
216 * 3. os private data [variable size]
218 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
219 * appropriate number of bytes.
220 * the usbi_transfer includes the number of allocated packets, so you can
221 * determine the size of the transfer and hence the start and length of the
225 struct usbi_transfer {
227 struct list_head list;
228 struct timeval timeout;
233 #define __USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
234 ((struct libusb_transfer *)(((void *)(transfer)) \
235 + sizeof(struct usbi_transfer)))
236 #define __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
237 ((struct usbi_transfer *)(((void *)(transfer)) \
238 - sizeof(struct usbi_transfer)))
240 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
242 return ((void *)transfer) + sizeof(struct usbi_transfer)
243 + sizeof(struct libusb_transfer)
244 + (transfer->num_iso_packets
245 * sizeof(struct libusb_iso_packet_descriptor));
250 /* All standard descriptors have these 2 fields in common */
251 struct usb_descriptor_header {
253 uint8_t bDescriptorType;
256 /* shared data and functions */
258 void usbi_io_init(struct libusb_context *ctx);
260 struct libusb_device *usbi_alloc_device(struct libusb_context *ctx,
261 unsigned long session_id);
262 struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx,
263 unsigned long session_id);
264 int usbi_sanitize_device(struct libusb_device *dev);
265 void usbi_handle_disconnect(struct libusb_device_handle *handle);
267 void usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
268 enum libusb_transfer_status status);
269 void usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
271 int usbi_parse_descriptor(unsigned char *source, char *descriptor, void *dest,
273 int usbi_get_config_index_by_value(struct libusb_device *dev,
274 uint8_t bConfigurationValue, int *idx);
279 /* must come first */
280 struct libusb_pollfd pollfd;
282 struct list_head list;
285 int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events);
286 void usbi_remove_pollfd(struct libusb_context *ctx, int fd);
288 /* device discovery */
290 /* we traverse usbfs without knowing how many devices we are going to find.
291 * so we create this discovered_devs model which is similar to a linked-list
292 * which grows when required. it can be freed once discovery has completed,
293 * eliminating the need for a list node in the libusb_device structure
295 struct discovered_devs {
298 struct libusb_device *devices[0];
301 struct discovered_devs *discovered_devs_append(
302 struct discovered_devs *discdevs, struct libusb_device *dev);
306 /* This is the interface that OS backends need to implement.
307 * All fields are mandatory, except ones explicitly noted as optional. */
308 struct usbi_os_backend {
309 /* A human-readable name for your backend, e.g. "Linux usbfs" */
312 /* Perform initialization of your backend. You might use this function
313 * to determine specific capabilities of the system, allocate required
314 * data structures for later, etc.
316 * This function is called when a libusb user initializes the library
319 * Return 0 on success, or a LIBUSB_ERROR code on failure.
321 int (*init)(struct libusb_context *ctx);
323 /* Deinitialization. Optional. This function should destroy anything
324 * that was set up by init.
326 * This function is called when the user deinitializes the library.
330 /* Enumerate all the USB devices on the system, returning them in a list
331 * of discovered devices.
333 * Your implementation should enumerate all devices on the system,
334 * regardless of whether they have been seen before or not.
336 * When you have found a device, compute a session ID for it. The session
337 * ID should uniquely represent that particular device for that particular
338 * connection session since boot (i.e. if you disconnect and reconnect a
339 * device immediately after, it should be assigned a different session ID).
340 * If your OS cannot provide a unique session ID as described above,
341 * presenting a session ID of (bus_number << 8 | device_address) should
342 * be sufficient. Bus numbers and device addresses wrap and get reused,
343 * but that is an unlikely case.
345 * After computing a session ID for a device, call
346 * usbi_get_device_by_session_id(). This function checks if libusb already
347 * knows about the device, and if so, it provides you with a libusb_device
350 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
351 * a new device structure for the device. Call usbi_alloc_device() to
352 * obtain a new libusb_device structure with reference count 1. Populate
353 * the bus_number and device_address attributes of the new device, and
354 * perform any other internal backend initialization you need to do. At
355 * this point, you should be ready to provide device descriptors and so
356 * on through the get_*_descriptor functions. Finally, call
357 * usbi_sanitize_device() to perform some final sanity checks on the
358 * device. Assuming all of the above succeeded, we can now continue.
359 * If any of the above failed, remember to unreference the device that
360 * was returned by usbi_alloc_device().
362 * At this stage we have a populated libusb_device structure (either one
363 * that was found earlier, or one that we have just allocated and
364 * populated). This can now be added to the discovered devices list
365 * using discovered_devs_append(). Note that discovered_devs_append()
366 * may reallocate the list, returning a new location for it, and also
367 * note that reallocation can fail. Your backend should handle these
368 * error conditions appropriately.
370 * This function should not generate any bus I/O and should not block.
371 * If I/O is required (e.g. reading the active configuration value), it is
372 * OK to ignore these suggestions :)
374 * This function is executed when the user wishes to retrieve a list
375 * of USB devices connected to the system.
377 * Return 0 on success, or a LIBUSB_ERROR code on failure.
379 int (*get_device_list)(struct libusb_context *ctx,
380 struct discovered_devs **discdevs);
382 /* Open a device for I/O and other USB operations. The device handle
383 * is preallocated for you, you can retrieve the device in question
384 * through handle->dev.
386 * Your backend should allocate any internal resources required for I/O
387 * and other operations so that those operations can happen (hopefully)
388 * without hiccup. This is also a good place to inform libusb that it
389 * should monitor certain file descriptors related to this device -
390 * see the usbi_add_pollfd() function.
392 * This function should not generate any bus I/O and should not block.
394 * This function is called when the user attempts to obtain a device
395 * handle for a device.
399 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
400 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
402 * - another LIBUSB_ERROR code on other failure
404 * Do not worry about freeing the handle on failed open, the upper layers
407 int (*open)(struct libusb_device_handle *handle);
409 /* Close a device such that the handle cannot be used again. Your backend
410 * should destroy any resources that were allocated in the open path.
411 * This may also be a good place to call usbi_remove_pollfd() to inform
412 * libusb of any file descriptors associated with this device that should
413 * no longer be monitored.
415 * This function is called when the user closes a device handle.
417 void (*close)(struct libusb_device_handle *handle);
419 /* Retrieve the device descriptor from a device.
421 * The descriptor should be retrieved from memory, NOT via bus I/O to the
422 * device. This means that you may have to cache it in a private structure
423 * during get_device_list enumeration. Alternatively, you may be able
424 * to retrieve it from a kernel interface (some Linux setups can do this)
425 * still without generating bus I/O.
427 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
428 * buffer, which is guaranteed to be big enough.
430 * This function is called when sanity-checking a device before adding
431 * it to the list of discovered devices, and also when the user requests
432 * to read the device descriptor.
434 * This function is expected to return the descriptor in bus-endian format
435 * (LE). If it returns the multi-byte values in host-endian format,
436 * set the host_endian output parameter to "1".
438 * Return 0 on success or a LIBUSB_ERROR code on failure.
440 int (*get_device_descriptor)(struct libusb_device *device,
441 unsigned char *buffer, int *host_endian);
443 /* Get the ACTIVE configuration descriptor for a device.
445 * The descriptor should be retrieved from memory, NOT via bus I/O to the
446 * device. This means that you may have to cache it in a private structure
447 * during get_device_list enumeration. You may also have to keep track
448 * of which configuration is active when the user changes it.
450 * This function is expected to write len bytes of data into buffer, which
451 * is guaranteed to be big enough. If you can only do a partial write,
452 * return an error code.
454 * This function is expected to return the descriptor in bus-endian format
455 * (LE). If it returns the multi-byte values in host-endian format,
456 * set the host_endian output parameter to "1".
460 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
461 * - another LIBUSB_ERROR code on other failure
463 int (*get_active_config_descriptor)(struct libusb_device *device,
464 unsigned char *buffer, size_t len, int *host_endian);
466 /* Get a specific configuration descriptor for a device.
468 * The descriptor should be retrieved from memory, NOT via bus I/O to the
469 * device. This means that you may have to cache it in a private structure
470 * during get_device_list enumeration.
472 * The requested descriptor is expressed as a zero-based index (i.e. 0
473 * indicates that we are requesting the first descriptor). The index does
474 * not (necessarily) equal the bConfigurationValue of the configuration
477 * This function is expected to write len bytes of data into buffer, which
478 * is guaranteed to be big enough. If you can only do a partial write,
479 * return an error code.
481 * This function is expected to return the descriptor in bus-endian format
482 * (LE). If it returns the multi-byte values in host-endian format,
483 * set the host_endian output parameter to "1".
485 * Return 0 on success or a LIBUSB_ERROR code on failure.
487 int (*get_config_descriptor)(struct libusb_device *device,
488 uint8_t config_index, unsigned char *buffer, size_t len,
491 /* Get the bConfigurationValue for the active configuration for a device.
492 * Optional. This should only be implemented if you can retrieve it from
493 * cache (don't generate I/O).
495 * If you cannot retrieve this from cache, either do not implement this
496 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
497 * libusb to retrieve the information through a standard control transfer.
499 * This function must be non-blocking.
502 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
504 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
506 * - another LIBUSB_ERROR code on other failure.
508 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
510 /* Set the active configuration for a device.
512 * A configuration value of -1 should put the device in unconfigured state.
514 * This function can block.
518 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
519 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
520 * configuration cannot be changed)
521 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
523 * - another LIBUSB_ERROR code on other failure.
525 int (*set_configuration)(struct libusb_device_handle *handle, int config);
527 /* Claim an interface. When claimed, the application can then perform
528 * I/O to an interface's endpoints.
530 * This function should not generate any bus I/O and should not block.
531 * Interface claiming is a logical operation that simply ensures that
532 * no other drivers/applications are using the interface, and after
533 * claiming, no other drivers/applicatiosn can use the interface because
538 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
539 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
540 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
542 * - another LIBUSB_ERROR code on other failure
544 int (*claim_interface)(struct libusb_device_handle *handle, int iface);
546 /* Release a previously claimed interface.
548 * This function should also generate a SET_INTERFACE control request,
549 * resetting the alternate setting of that interface to 0. It's OK for
550 * this function to block as a result.
552 * You will only ever be asked to release an interface which was
553 * successfully claimed earlier.
557 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
559 * - another LIBUSB_ERROR code on other failure
561 int (*release_interface)(struct libusb_device_handle *handle, int iface);
563 /* Set the alternate setting for an interface.
565 * You will only ever be asked to set the alternate setting for an
566 * interface which was successfully claimed earlier.
568 * It's OK for this function to block.
572 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
573 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
575 * - another LIBUSB_ERROR code on other failure
577 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
578 int iface, int altsetting);
580 /* Clear a halt/stall condition on an endpoint.
582 * It's OK for this function to block.
586 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
587 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
589 * - another LIBUSB_ERROR code on other failure
591 int (*clear_halt)(struct libusb_device_handle *handle,
592 unsigned char endpoint);
594 /* Perform a USB port reset to reinitialize a device.
596 * If possible, the handle should still be usable after the reset
597 * completes, assuming that the device descriptors did not change during
598 * reset and all previous interface state can be restored.
600 * If something changes, or you cannot easily locate/verify the resetted
601 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
602 * to close the old handle and re-enumerate the device.
606 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
607 * has been disconnected since it was opened
608 * - another LIBUSB_ERROR code on other failure
610 int (*reset_device)(struct libusb_device_handle *handle);
612 /* Determine if a kernel driver is active on an interface. Optional.
614 * The presence of a kernel driver on an interface indicates that any
615 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
618 * - 0 if no driver is active
619 * - 1 if a driver is active
620 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
622 * - another LIBUSB_ERROR code on other failure
624 int (*kernel_driver_active)(struct libusb_device_handle *handle,
627 /* Detach a kernel driver from an interface. Optional.
629 * After detaching a kernel driver, the interface should be available
634 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
635 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
636 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
638 * - another LIBUSB_ERROR code on other failure
640 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
643 /* Destroy a device. Optional.
645 * This function is called when the last reference to a device is
646 * destroyed. It should free any resources allocated in the get_device_list
649 void (*destroy_device)(struct libusb_device *dev);
651 /* Submit a transfer. Your implementation should take the transfer,
652 * morph it into whatever form your platform requires, and submit it
655 * This function must not block.
659 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
660 * - another LIBUSB_ERROR code on other failure
662 int (*submit_transfer)(struct usbi_transfer *itransfer);
664 /* Cancel a previously submitted transfer.
666 * This function must not block. The transfer cancellation must complete
667 * later, resulting in a call to usbi_handle_transfer_cancellation()
668 * from the context of handle_events.
670 int (*cancel_transfer)(struct usbi_transfer *itransfer);
672 /* Clear a transfer as if it has completed or cancelled, but do not
673 * report any completion/cancellation to the library. You should free
674 * all private data from the transfer as if you were just about to report
675 * completion or cancellation.
677 * This function might seem a bit out of place. It is used when libusb
678 * detects a disconnected device - it calls this function for all pending
679 * transfers before reporting completion (with the disconnect code) to
680 * the user. Maybe we can improve upon this internal interface in future.
682 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
684 /* Handle any pending events. This involves monitoring any active
685 * transfers and processing their completion or cancellation.
687 * The function is passed an array of pollfd structures (size nfds)
688 * as a result of the poll() system call. The num_ready parameter
689 * indicates the number of file descriptors that have reported events
690 * (i.e. the poll() return value). This should be enough information
691 * for you to determine which actions need to be taken on the currently
694 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
695 * For completed transfers, call usbi_handle_transfer_completion().
696 * For control/bulk/interrupt transfers, populate the "transferred"
697 * element of the appropriate usbi_transfer structure before calling the
698 * above functions. For isochronous transfers, populate the status and
699 * transferred fields of the iso packet descriptors of the transfer.
701 * This function should also be able to detect disconnection of the
702 * device, reporting that situation with usbi_handle_disconnect().
704 * Return 0 on success, or a LIBUSB_ERROR code on failure.
706 int (*handle_events)(struct libusb_context *ctx,
707 struct pollfd *fds, nfds_t nfds, int num_ready);
709 /* Number of bytes to reserve for per-device private backend data.
710 * This private data area is accessible through the "os_priv" field of
711 * struct libusb_device. */
712 size_t device_priv_size;
714 /* Number of bytes to reserve for per-handle private backend data.
715 * This private data area is accessible through the "os_priv" field of
716 * struct libusb_device. */
717 size_t device_handle_priv_size;
719 /* Number of bytes to reserve for per-transfer private backend data.
720 * This private data area is accessible by calling
721 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
723 size_t transfer_priv_size;
725 /* Mumber of additional bytes for os_priv for each iso packet.
726 * Can your backend use this? */
727 /* FIXME: linux can't use this any more. if other OS's cannot either,
728 * then remove this */
729 size_t add_iso_packet_size;
732 extern const struct usbi_os_backend * const usbi_backend;
734 extern const struct usbi_os_backend linux_usbfs_backend;