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(enum usbi_log_level, const char *function, const char *format, ...);
117 #ifdef ENABLE_LOGGING
118 #define _usbi_log(level, fmt...) usbi_log(level, __FUNCTION__, fmt)
120 #define _usbi_log(level, fmt...)
123 #ifdef ENABLE_DEBUG_LOGGING
124 #define usbi_dbg(fmt...) _usbi_log(LOG_LEVEL_DEBUG, fmt)
126 #define usbi_dbg(fmt...)
129 #define usbi_info(fmt...) _usbi_log(LOG_LEVEL_INFO, fmt)
130 #define usbi_warn(fmt...) _usbi_log(LOG_LEVEL_WARNING, fmt)
131 #define usbi_err(fmt...) _usbi_log(LOG_LEVEL_ERROR, fmt)
133 struct libusb_device {
134 /* lock protects refcnt, everything else is finalized at initialization
136 pthread_mutex_t lock;
140 uint8_t device_address;
141 uint8_t num_configurations;
143 struct list_head list;
144 unsigned long session_data;
145 unsigned char os_priv[0];
148 struct libusb_device_handle {
149 /* lock protects claimed_interfaces */
150 pthread_mutex_t lock;
151 unsigned long claimed_interfaces;
153 struct list_head list;
154 struct libusb_device *dev;
155 unsigned char os_priv[0];
158 #define USBI_TRANSFER_TIMED_OUT (1<<0)
160 /* in-memory transfer layout:
162 * 1. struct usbi_transfer
163 * 2. struct libusb_transfer (which includes iso packets) [variable size]
164 * 3. os private data [variable size]
166 * from a libusb_transfer, you can get the usbi_transfer by rewinding the
167 * appropriate number of bytes.
168 * the usbi_transfer includes the number of allocated packets, so you can
169 * determine the size of the transfer and hence the start and length of the
173 struct usbi_transfer {
175 struct list_head list;
176 struct timeval timeout;
181 #define __USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \
182 ((struct libusb_transfer *)(((void *)(transfer)) \
183 + sizeof(struct usbi_transfer)))
184 #define __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \
185 ((struct usbi_transfer *)(((void *)(transfer)) \
186 - sizeof(struct usbi_transfer)))
188 static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer)
190 return ((void *)transfer) + sizeof(struct usbi_transfer)
191 + sizeof(struct libusb_transfer)
192 + (transfer->num_iso_packets
193 * sizeof(struct libusb_iso_packet_descriptor));
198 /* All standard descriptors have these 2 fields in common */
199 struct usb_descriptor_header {
201 uint8_t bDescriptorType;
204 /* shared data and functions */
206 extern struct list_head usbi_open_devs;
207 extern pthread_mutex_t usbi_open_devs_lock;
209 void usbi_io_init(void);
211 struct libusb_device *usbi_alloc_device(unsigned long session_id);
212 struct libusb_device *usbi_get_device_by_session_id(unsigned long session_id);
213 int usbi_sanitize_device(struct libusb_device *dev);
214 void usbi_handle_disconnect(struct libusb_device_handle *handle);
216 void usbi_handle_transfer_completion(struct usbi_transfer *itransfer,
217 enum libusb_transfer_status status);
218 void usbi_handle_transfer_cancellation(struct usbi_transfer *transfer);
220 int usbi_parse_descriptor(unsigned char *source, char *descriptor, void *dest,
222 int usbi_get_config_index_by_value(struct libusb_device *dev,
223 uint8_t bConfigurationValue, int *idx);
228 /* must come first */
229 struct libusb_pollfd pollfd;
231 struct list_head list;
234 int usbi_add_pollfd(int fd, short events);
235 void usbi_remove_pollfd(int fd);
237 /* device discovery */
239 /* we traverse usbfs without knowing how many devices we are going to find.
240 * so we create this discovered_devs model which is similar to a linked-list
241 * which grows when required. it can be freed once discovery has completed,
242 * eliminating the need for a list node in the libusb_device structure
244 struct discovered_devs {
247 struct libusb_device *devices[0];
250 struct discovered_devs *discovered_devs_append(
251 struct discovered_devs *discdevs, struct libusb_device *dev);
255 /* This is the interface that OS backends need to implement.
256 * All fields are mandatory, except ones explicitly noted as optional. */
257 struct usbi_os_backend {
258 /* A human-readable name for your backend, e.g. "Linux usbfs" */
261 /* Perform initialization of your backend. You might use this function
262 * to determine specific capabilities of the system, allocate required
263 * data structures for later, etc.
265 * This function is called when a libusb user initializes the library
268 * Return 0 on success, or a LIBUSB_ERROR code on failure.
272 /* Deinitialization. Optional. This function should destroy anything
273 * that was set up by init.
275 * This function is called when the user deinitializes the library.
279 /* Enumerate all the USB devices on the system, returning them in a list
280 * of discovered devices.
282 * Your implementation should enumerate all devices on the system,
283 * regardless of whether they have been seen before or not.
285 * When you have found a device, compute a session ID for it. The session
286 * ID should uniquely represent that particular device for that particular
287 * connection session since boot (i.e. if you disconnect and reconnect a
288 * device immediately after, it should be assigned a different session ID).
289 * If your OS cannot provide a unique session ID as described above,
290 * presenting a session ID of (bus_number << 8 | device_address) should
291 * be sufficient. Bus numbers and device addresses wrap and get reused,
292 * but that is an unlikely case.
294 * After computing a session ID for a device, call
295 * usbi_get_device_by_session_id(). This function checks if libusb already
296 * knows about the device, and if so, it provides you with a libusb_device
299 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
300 * a new device structure for the device. Call usbi_alloc_device() to
301 * obtain a new libusb_device structure with reference count 1. Populate
302 * the bus_number and device_address attributes of the new device, and
303 * perform any other internal backend initialization you need to do. At
304 * this point, you should be ready to provide device descriptors and so
305 * on through the get_*_descriptor functions. Finally, call
306 * usbi_sanitize_device() to perform some final sanity checks on the
307 * device. Assuming all of the above succeeded, we can now continue.
308 * If any of the above failed, remember to unreference the device that
309 * was returned by usbi_alloc_device().
311 * At this stage we have a populated libusb_device structure (either one
312 * that was found earlier, or one that we have just allocated and
313 * populated). This can now be added to the discovered devices list
314 * using discovered_devs_append(). Note that discovered_devs_append()
315 * may reallocate the list, returning a new location for it, and also
316 * note that reallocation can fail. Your backend should handle these
317 * error conditions appropriately.
319 * This function should not generate any bus I/O and should not block.
320 * If I/O is required (e.g. reading the active configuration value), it is
321 * OK to ignore these suggestions :)
323 * This function is executed when the user wishes to retrieve a list
324 * of USB devices connected to the system.
326 * Return 0 on success, or a LIBUSB_ERROR code on failure.
328 int (*get_device_list)(struct discovered_devs **discdevs);
330 /* Open a device for I/O and other USB operations. The device handle
331 * is preallocated for you, you can retrieve the device in question
332 * through handle->dev.
334 * Your backend should allocate any internal resources required for I/O
335 * and other operations so that those operations can happen (hopefully)
336 * without hiccup. This is also a good place to inform libusb that it
337 * should monitor certain file descriptors related to this device -
338 * see the usbi_add_pollfd() function.
340 * This function should not generate any bus I/O and should not block.
342 * This function is called when the user attempts to obtain a device
343 * handle for a device.
347 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
348 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
350 * - another LIBUSB_ERROR code on other failure
352 * Do not worry about freeing the handle on failed open, the upper layers
355 int (*open)(struct libusb_device_handle *handle);
357 /* Close a device such that the handle cannot be used again. Your backend
358 * should destroy any resources that were allocated in the open path.
359 * This may also be a good place to call usbi_remove_pollfd() to inform
360 * libusb of any file descriptors associated with this device that should
361 * no longer be monitored.
363 * This function is called when the user closes a device handle.
365 void (*close)(struct libusb_device_handle *handle);
367 /* Retrieve the device descriptor from a device.
369 * The descriptor should be retrieved from memory, NOT via bus I/O to the
370 * device. This means that you may have to cache it in a private structure
371 * during get_device_list enumeration. Alternatively, you may be able
372 * to retrieve it from a kernel interface (some Linux setups can do this)
373 * still without generating bus I/O.
375 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
376 * buffer, which is guaranteed to be big enough.
378 * This function is called when sanity-checking a device before adding
379 * it to the list of discovered devices, and also when the user requests
380 * to read the device descriptor.
382 * This function is expected to return the descriptor in bus-endian format
383 * (LE). If it returns the multi-byte values in host-endian format,
384 * set the host_endian output parameter to "1".
386 * Return 0 on success or a LIBUSB_ERROR code on failure.
388 int (*get_device_descriptor)(struct libusb_device *device,
389 unsigned char *buffer, int *host_endian);
391 /* Get the ACTIVE configuration descriptor for a device.
393 * The descriptor should be retrieved from memory, NOT via bus I/O to the
394 * device. This means that you may have to cache it in a private structure
395 * during get_device_list enumeration. You may also have to keep track
396 * of which configuration is active when the user changes it.
398 * This function is expected to write len bytes of data into buffer, which
399 * is guaranteed to be big enough. If you can only do a partial write,
400 * return an error code.
402 * This function is expected to return the descriptor in bus-endian format
403 * (LE). If it returns the multi-byte values in host-endian format,
404 * set the host_endian output parameter to "1".
408 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
409 * - another LIBUSB_ERROR code on other failure
411 int (*get_active_config_descriptor)(struct libusb_device *device,
412 unsigned char *buffer, size_t len, int *host_endian);
414 /* Get a specific configuration descriptor for a device.
416 * The descriptor should be retrieved from memory, NOT via bus I/O to the
417 * device. This means that you may have to cache it in a private structure
418 * during get_device_list enumeration.
420 * The requested descriptor is expressed as a zero-based index (i.e. 0
421 * indicates that we are requesting the first descriptor). The index does
422 * not (necessarily) equal the bConfigurationValue of the configuration
425 * This function is expected to write len bytes of data into buffer, which
426 * is guaranteed to be big enough. If you can only do a partial write,
427 * return an error code.
429 * This function is expected to return the descriptor in bus-endian format
430 * (LE). If it returns the multi-byte values in host-endian format,
431 * set the host_endian output parameter to "1".
433 * Return 0 on success or a LIBUSB_ERROR code on failure.
435 int (*get_config_descriptor)(struct libusb_device *device,
436 uint8_t config_index, unsigned char *buffer, size_t len,
439 /* Get the bConfigurationValue for the active configuration for a device.
440 * Optional. This should only be implemented if you can retrieve it from
441 * cache (don't generate I/O).
443 * If you cannot retrieve this from cache, either do not implement this
444 * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause
445 * libusb to retrieve the information through a standard control transfer.
447 * This function must be non-blocking.
450 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
452 * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without
454 * - another LIBUSB_ERROR code on other failure.
456 int (*get_configuration)(struct libusb_device_handle *handle, int *config);
458 /* Set the active configuration for a device.
460 * A configuration value of -1 should put the device in unconfigured state.
462 * This function can block.
466 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
467 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
468 * configuration cannot be changed)
469 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
471 * - another LIBUSB_ERROR code on other failure.
473 int (*set_configuration)(struct libusb_device_handle *handle, int config);
475 /* Claim an interface. When claimed, the application can then perform
476 * I/O to an interface's endpoints.
478 * This function should not generate any bus I/O and should not block.
479 * Interface claiming is a logical operation that simply ensures that
480 * no other drivers/applications are using the interface, and after
481 * claiming, no other drivers/applicatiosn can use the interface because
486 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
487 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
488 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
490 * - another LIBUSB_ERROR code on other failure
492 int (*claim_interface)(struct libusb_device_handle *handle, int iface);
494 /* Release a previously claimed interface.
496 * This function should also generate a SET_INTERFACE control request,
497 * resetting the alternate setting of that interface to 0. It's OK for
498 * this function to block as a result.
500 * You will only ever be asked to release an interface which was
501 * successfully claimed earlier.
505 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
507 * - another LIBUSB_ERROR code on other failure
509 int (*release_interface)(struct libusb_device_handle *handle, int iface);
511 /* Set the alternate setting for an interface.
513 * You will only ever be asked to set the alternate setting for an
514 * interface which was successfully claimed earlier.
516 * It's OK for this function to block.
520 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
521 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
523 * - another LIBUSB_ERROR code on other failure
525 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
526 int iface, int altsetting);
528 /* Clear a halt/stall condition on an endpoint.
530 * It's OK for this function to block.
534 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
535 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
537 * - another LIBUSB_ERROR code on other failure
539 int (*clear_halt)(struct libusb_device_handle *handle,
540 unsigned char endpoint);
542 /* Perform a USB port reset to reinitialize a device.
544 * If possible, the handle should still be usable after the reset
545 * completes, assuming that the device descriptors did not change during
546 * reset and all previous interface state can be restored.
548 * If something changes, or you cannot easily locate/verify the resetted
549 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
550 * to close the old handle and re-enumerate the device.
554 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
555 * has been disconnected since it was opened
556 * - another LIBUSB_ERROR code on other failure
558 int (*reset_device)(struct libusb_device_handle *handle);
560 /* Determine if a kernel driver is active on an interface. Optional.
562 * The presence of a kernel driver on an interface indicates that any
563 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
566 * - 0 if no driver is active
567 * - 1 if a driver is active
568 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
570 * - another LIBUSB_ERROR code on other failure
572 int (*kernel_driver_active)(struct libusb_device_handle *handle,
575 /* Detach a kernel driver from an interface. Optional.
577 * After detaching a kernel driver, the interface should be available
582 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
583 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
584 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
586 * - another LIBUSB_ERROR code on other failure
588 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
591 /* Destroy a device. Optional.
593 * This function is called when the last reference to a device is
594 * destroyed. It should free any resources allocated in the get_device_list
597 void (*destroy_device)(struct libusb_device *dev);
599 /* Submit a transfer. Your implementation should take the transfer,
600 * morph it into whatever form your platform requires, and submit it
603 * This function must not block.
607 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
608 * - another LIBUSB_ERROR code on other failure
610 int (*submit_transfer)(struct usbi_transfer *itransfer);
612 /* Cancel a previously submitted transfer.
614 * This function must not block. The transfer cancellation must complete
615 * later, resulting in a call to usbi_handle_transfer_cancellation()
616 * from the context of handle_events.
618 int (*cancel_transfer)(struct usbi_transfer *itransfer);
620 /* Clear a transfer as if it has completed or cancelled, but do not
621 * report any completion/cancellation to the library. You should free
622 * all private data from the transfer as if you were just about to report
623 * completion or cancellation.
625 * This function might seem a bit out of place. It is used when libusb
626 * detects a disconnected device - it calls this function for all pending
627 * transfers before reporting completion (with the disconnect code) to
628 * the user. Maybe we can improve upon this internal interface in future.
630 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
632 /* Handle any pending events. This involves monitoring any active
633 * transfers and processing their completion or cancellation.
635 * The function is passed an array of pollfd structures (size nfds)
636 * as a result of the poll() system call. The num_ready parameter
637 * indicates the number of file descriptors that have reported events
638 * (i.e. the poll() return value). This should be enough information
639 * for you to determine which actions need to be taken on the currently
642 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
643 * For completed transfers, call usbi_handle_transfer_completion().
644 * For control/bulk/interrupt transfers, populate the "transferred"
645 * element of the appropriate usbi_transfer structure before calling the
646 * above functions. For isochronous transfers, populate the status and
647 * transferred fields of the iso packet descriptors of the transfer.
649 * This function should also be able to detect disconnection of the
650 * device, reporting that situation with usbi_handle_disconnect().
652 * Return 0 on success, or a LIBUSB_ERROR code on failure.
654 int (*handle_events)(struct pollfd *fds, nfds_t nfds, int num_ready);
656 /* Number of bytes to reserve for per-device private backend data.
657 * This private data area is accessible through the "os_priv" field of
658 * struct libusb_device. */
659 size_t device_priv_size;
661 /* Number of bytes to reserve for per-handle private backend data.
662 * This private data area is accessible through the "os_priv" field of
663 * struct libusb_device. */
664 size_t device_handle_priv_size;
666 /* Number of bytes to reserve for per-transfer private backend data.
667 * This private data area is accessible by calling
668 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
670 size_t transfer_priv_size;
672 /* Mumber of additional bytes for os_priv for each iso packet.
673 * Can your backend use this? */
674 /* FIXME: linux can't use this any more. if other OS's cannot either,
675 * then remove this */
676 size_t add_iso_packet_size;
679 extern const struct usbi_os_backend * const usbi_backend;
681 extern const struct usbi_os_backend linux_usbfs_backend;