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);
221 int usbi_get_config_index_by_value(struct libusb_device *dev,
222 uint8_t bConfigurationValue, int *idx);
227 /* must come first */
228 struct libusb_pollfd pollfd;
230 struct list_head list;
233 int usbi_add_pollfd(int fd, short events);
234 void usbi_remove_pollfd(int fd);
236 /* device discovery */
238 /* we traverse usbfs without knowing how many devices we are going to find.
239 * so we create this discovered_devs model which is similar to a linked-list
240 * which grows when required. it can be freed once discovery has completed,
241 * eliminating the need for a list node in the libusb_device structure
243 struct discovered_devs {
246 struct libusb_device *devices[0];
249 struct discovered_devs *discovered_devs_append(
250 struct discovered_devs *discdevs, struct libusb_device *dev);
254 /* This is the interface that OS backends need to implement.
255 * All fields are mandatory, except ones explicitly noted as optional. */
256 struct usbi_os_backend {
257 /* A human-readable name for your backend, e.g. "Linux usbfs" */
260 /* Perform initialization of your backend. You might use this function
261 * to determine specific capabilities of the system, allocate required
262 * data structures for later, etc.
264 * This function is called when a libusb user initializes the library
267 * Return 0 on success, or a LIBUSB_ERROR code on failure.
271 /* Deinitialization. Optional. This function should destroy anything
272 * that was set up by init.
274 * This function is called when the user deinitializes the library.
278 /* Enumerate all the USB devices on the system, returning them in a list
279 * of discovered devices.
281 * Your implementation should enumerate all devices on the system,
282 * regardless of whether they have been seen before or not.
284 * When you have found a device, compute a session ID for it. The session
285 * ID should uniquely represent that particular device for that particular
286 * connection session since boot (i.e. if you disconnect and reconnect a
287 * device immediately after, it should be assigned a different session ID).
288 * If your OS cannot provide a unique session ID as described above,
289 * presenting a session ID of (bus_number << 8 | device_address) should
290 * be sufficient. Bus numbers and device addresses wrap and get reused,
291 * but that is an unlikely case.
293 * After computing a session ID for a device, call
294 * usbi_get_device_by_session_id(). This function checks if libusb already
295 * knows about the device, and if so, it provides you with a libusb_device
298 * If usbi_get_device_by_session_id() returns NULL, it is time to allocate
299 * a new device structure for the device. Call usbi_alloc_device() to
300 * obtain a new libusb_device structure with reference count 1. Populate
301 * the bus_number and device_address attributes of the new device, and
302 * perform any other internal backend initialization you need to do. At
303 * this point, you should be ready to provide device descriptors and so
304 * on through the get_*_descriptor functions. Finally, call
305 * usbi_sanitize_device() to perform some final sanity checks on the
306 * device. Assuming all of the above succeeded, we can now continue.
307 * If any of the above failed, remember to unreference the device that
308 * was returned by usbi_alloc_device().
310 * At this stage we have a populated libusb_device structure (either one
311 * that was found earlier, or one that we have just allocated and
312 * populated). This can now be added to the discovered devices list
313 * using discovered_devs_append(). Note that discovered_devs_append()
314 * may reallocate the list, returning a new location for it, and also
315 * note that reallocation can fail. Your backend should handle these
316 * error conditions appropriately.
318 * This function should not generate any bus I/O and should not block.
319 * If I/O is required (e.g. reading the active configuration value), it is
320 * OK to ignore these suggestions :)
322 * This function is executed when the user wishes to retrieve a list
323 * of USB devices connected to the system.
325 * Return 0 on success, or a LIBUSB_ERROR code on failure.
327 int (*get_device_list)(struct discovered_devs **discdevs);
329 /* Open a device for I/O and other USB operations. The device handle
330 * is preallocated for you, you can retrieve the device in question
331 * through handle->dev.
333 * Your backend should allocate any internal resources required for I/O
334 * and other operations so that those operations can happen (hopefully)
335 * without hiccup. This is also a good place to inform libusb that it
336 * should monitor certain file descriptors related to this device -
337 * see the usbi_add_pollfd() function.
339 * This function should not generate any bus I/O and should not block.
341 * This function is called when the user attempts to obtain a device
342 * handle for a device.
346 * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions
347 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since
349 * - another LIBUSB_ERROR code on other failure
351 * Do not worry about freeing the handle on failed open, the upper layers
354 int (*open)(struct libusb_device_handle *handle);
356 /* Close a device such that the handle cannot be used again. Your backend
357 * should destroy any resources that were allocated in the open path.
358 * This may also be a good place to call usbi_remove_pollfd() to inform
359 * libusb of any file descriptors associated with this device that should
360 * no longer be monitored.
362 * This function is called when the user closes a device handle.
364 void (*close)(struct libusb_device_handle *handle);
366 /* Retrieve the device descriptor from a device.
368 * The descriptor should be retrieved from memory, NOT via bus I/O to the
369 * device. This means that you may have to cache it in a private structure
370 * during get_device_list enumeration. Alternatively, you may be able
371 * to retrieve it from a kernel interface (some Linux setups can do this)
372 * still without generating bus I/O.
374 * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into
375 * buffer, which is guaranteed to be big enough.
377 * This function is called when sanity-checking a device before adding
378 * it to the list of discovered devices, and also when the user requests
379 * to read the device descriptor.
381 * Return 0 on success or a LIBUSB_ERROR code on failure.
383 int (*get_device_descriptor)(struct libusb_device *device,
384 unsigned char *buffer);
386 /* Get the ACTIVE configuration descriptor for a device.
388 * The descriptor should be retrieved from memory, NOT via bus I/O to the
389 * device. This means that you may have to cache it in a private structure
390 * during get_device_list enumeration. You may also have to keep track
391 * of which configuration is active when the user changes it.
393 * This function is expected to write len bytes of data into buffer, which
394 * is guaranteed to be big enough. If you can only do a partial write,
395 * return an error code.
399 * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state
400 * - another LIBUSB_ERROR code on other failure
402 int (*get_active_config_descriptor)(struct libusb_device *device,
403 unsigned char *buffer, size_t len);
405 /* Get a specific configuration descriptor for a device.
407 * The descriptor should be retrieved from memory, NOT via bus I/O to the
408 * device. This means that you may have to cache it in a private structure
409 * during get_device_list enumeration.
411 * The requested descriptor is expressed as a zero-based index (i.e. 0
412 * indicates that we are requesting the first descriptor). The index does
413 * not (necessarily) equal the bConfigurationValue of the configuration
416 * This function is expected to write len bytes of data into buffer, which
417 * is guaranteed to be big enough. If you can only do a partial write,
418 * return an error code.
420 * Return 0 on success or a LIBUSB_ERROR code on failure.
422 int (*get_config_descriptor)(struct libusb_device *device,
423 uint8_t config_index, unsigned char *buffer, size_t len);
425 /* Set the active configuration for a device.
427 * A configuration value of -1 should put the device in unconfigured state.
429 * This function can block.
433 * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
434 * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence
435 * configuration cannot be changed)
436 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
438 * - another LIBUSB_ERROR code on other failure.
440 int (*set_configuration)(struct libusb_device_handle *handle, int config);
442 /* Claim an interface. When claimed, the application can then perform
443 * I/O to an interface's endpoints.
445 * This function should not generate any bus I/O and should not block.
446 * Interface claiming is a logical operation that simply ensures that
447 * no other drivers/applications are using the interface, and after
448 * claiming, no other drivers/applicatiosn can use the interface because
453 * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist
454 * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app
455 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
457 * - another LIBUSB_ERROR code on other failure
459 int (*claim_interface)(struct libusb_device_handle *handle, int iface);
461 /* Release a previously claimed interface.
463 * This function should also generate a SET_INTERFACE control request,
464 * resetting the alternate setting of that interface to 0. It's OK for
465 * this function to block as a result.
467 * You will only ever be asked to release an interface which was
468 * successfully claimed earlier.
472 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
474 * - another LIBUSB_ERROR code on other failure
476 int (*release_interface)(struct libusb_device_handle *handle, int iface);
478 /* Set the alternate setting for an interface.
480 * You will only ever be asked to set the alternate setting for an
481 * interface which was successfully claimed earlier.
483 * It's OK for this function to block.
487 * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist
488 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
490 * - another LIBUSB_ERROR code on other failure
492 int (*set_interface_altsetting)(struct libusb_device_handle *handle,
493 int iface, int altsetting);
495 /* Clear a halt/stall condition on an endpoint.
497 * It's OK for this function to block.
501 * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist
502 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
504 * - another LIBUSB_ERROR code on other failure
506 int (*clear_halt)(struct libusb_device_handle *handle,
507 unsigned char endpoint);
509 /* Perform a USB port reset to reinitialize a device.
511 * If possible, the handle should still be usable after the reset
512 * completes, assuming that the device descriptors did not change during
513 * reset and all previous interface state can be restored.
515 * If something changes, or you cannot easily locate/verify the resetted
516 * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application
517 * to close the old handle and re-enumerate the device.
521 * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device
522 * has been disconnected since it was opened
523 * - another LIBUSB_ERROR code on other failure
525 int (*reset_device)(struct libusb_device_handle *handle);
527 /* Determine if a kernel driver is active on an interface. Optional.
529 * The presence of a kernel driver on an interface indicates that any
530 * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code.
533 * - 0 if no driver is active
534 * - 1 if a driver is active
535 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
537 * - another LIBUSB_ERROR code on other failure
539 int (*kernel_driver_active)(struct libusb_device_handle *handle,
542 /* Detach a kernel driver from an interface. Optional.
544 * After detaching a kernel driver, the interface should be available
549 * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active
550 * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist
551 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it
553 * - another LIBUSB_ERROR code on other failure
555 int (*detach_kernel_driver)(struct libusb_device_handle *handle,
558 /* Destroy a device. Optional.
560 * This function is called when the last reference to a device is
561 * destroyed. It should free any resources allocated in the get_device_list
564 void (*destroy_device)(struct libusb_device *dev);
566 /* Submit a transfer. Your implementation should take the transfer,
567 * morph it into whatever form your platform requires, and submit it
570 * This function must not block.
574 * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected
575 * - another LIBUSB_ERROR code on other failure
577 int (*submit_transfer)(struct usbi_transfer *itransfer);
579 /* Cancel a previously submitted transfer.
581 * This function must not block. The transfer cancellation must complete
582 * later, resulting in a call to usbi_handle_transfer_cancellation()
583 * from the context of handle_events.
585 int (*cancel_transfer)(struct usbi_transfer *itransfer);
587 /* Clear a transfer as if it has completed or cancelled, but do not
588 * report any completion/cancellation to the library. You should free
589 * all private data from the transfer as if you were just about to report
590 * completion or cancellation.
592 * This function might seem a bit out of place. It is used when libusb
593 * detects a disconnected device - it calls this function for all pending
594 * transfers before reporting completion (with the disconnect code) to
595 * the user. Maybe we can improve upon this internal interface in future.
597 void (*clear_transfer_priv)(struct usbi_transfer *itransfer);
599 /* Handle any pending events. This involves monitoring any active
600 * transfers and processing their completion or cancellation.
602 * The function is passed an array of pollfd structures (size nfds)
603 * as a result of the poll() system call. The num_ready parameter
604 * indicates the number of file descriptors that have reported events
605 * (i.e. the poll() return value). This should be enough information
606 * for you to determine which actions need to be taken on the currently
609 * For any cancelled transfers, call usbi_handle_transfer_cancellation().
610 * For completed transfers, call usbi_handle_transfer_completion().
611 * For control/bulk/interrupt transfers, populate the "transferred"
612 * element of the appropriate usbi_transfer structure before calling the
613 * above functions. For isochronous transfers, populate the status and
614 * transferred fields of the iso packet descriptors of the transfer.
616 * This function should also be able to detect disconnection of the
617 * device, reporting that situation with usbi_handle_disconnect().
619 * Return 0 on success, or a LIBUSB_ERROR code on failure.
621 int (*handle_events)(struct pollfd *fds, nfds_t nfds, int num_ready);
623 /* Number of bytes to reserve for per-device private backend data.
624 * This private data area is accessible through the "os_priv" field of
625 * struct libusb_device. */
626 size_t device_priv_size;
628 /* Number of bytes to reserve for per-handle private backend data.
629 * This private data area is accessible through the "os_priv" field of
630 * struct libusb_device. */
631 size_t device_handle_priv_size;
633 /* Number of bytes to reserve for per-transfer private backend data.
634 * This private data area is accessible by calling
635 * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance.
637 size_t transfer_priv_size;
639 /* Mumber of additional bytes for os_priv for each iso packet.
640 * Can your backend use this? */
641 /* FIXME: linux can't use this any more. if other OS's cannot either,
642 * then remove this */
643 size_t add_iso_packet_size;
646 extern const struct usbi_os_backend * const usbi_backend;
648 extern const struct usbi_os_backend linux_usbfs_backend;