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Diffstat (limited to 'include/libusb-1.0/os/libusbi.h')
| -rw-r--r-- | include/libusb-1.0/os/libusbi.h | 872 |
1 files changed, 872 insertions, 0 deletions
diff --git a/include/libusb-1.0/os/libusbi.h b/include/libusb-1.0/os/libusbi.h new file mode 100644 index 0000000..9b2fa70 --- /dev/null +++ b/include/libusb-1.0/os/libusbi.h @@ -0,0 +1,872 @@ +/* + * Internal header for libusb + * Copyright (C) 2007-2009 Daniel Drake <dsd@gentoo.org> + * Copyright (c) 2001 Johannes Erdfelt <johannes@erdfelt.com> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#ifndef __LIBUSBI_H__ +#define __LIBUSBI_H__ + +#include <config.h> + +#include <stddef.h> +#include <stdint.h> +#include <time.h> + +#include <libusb.h> + +/* Inside the libusb code, mark all public functions as follows: + * return_type API_EXPORTED function_name(params) { ... } + * But if the function returns a pointer, mark it as follows: + * DEFAULT_VISIBILITY return_type * LIBUSB_CALL function_name(params) { ... } + * In the libusb public header, mark all declarations as: + * return_type LIBUSB_CALL function_name(params); + */ +#define API_EXPORTED LIBUSB_CALL DEFAULT_VISIBILITY + +#define DEVICE_DESC_LENGTH 18 + +#define USB_MAXENDPOINTS 32 +#define USB_MAXINTERFACES 32 +#define USB_MAXCONFIG 8 + +struct list_head { + struct list_head *prev, *next; +}; + +/* Get an entry from the list + * ptr - the address of this list_head element in "type" + * type - the data type that contains "member" + * member - the list_head element in "type" + */ +#define list_entry(ptr, type, member) \ + ((type *)((uintptr_t)(ptr) - (uintptr_t)(&((type *)0L)->member))) + +/* Get each entry from a list + * pos - A structure pointer has a "member" element + * head - list head + * member - the list_head element in "pos" + * type - the type of the first parameter + */ +#define list_for_each_entry(pos, head, member, type) \ + for (pos = list_entry((head)->next, type, member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, type, member)) + +#define list_for_each_entry_safe(pos, n, head, member, type) \ + for (pos = list_entry((head)->next, type, member), \ + n = list_entry(pos->member.next, type, member); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, type, member)) + +#define list_empty(entry) ((entry)->next == (entry)) + +static inline void list_init(struct list_head *entry) +{ + entry->prev = entry->next = entry; +} + +static inline void list_add(struct list_head *entry, struct list_head *head) +{ + entry->next = head->next; + entry->prev = head; + + head->next->prev = entry; + head->next = entry; +} + +static inline void list_add_tail(struct list_head *entry, + struct list_head *head) +{ + entry->next = head; + entry->prev = head->prev; + + head->prev->next = entry; + head->prev = entry; +} + +static inline void list_del(struct list_head *entry) +{ + entry->next->prev = entry->prev; + entry->prev->next = entry->next; +} + +#define container_of(ptr, type, member) ({ \ + const typeof( ((type *)0)->member ) *__mptr = (ptr); \ + (type *)( (char *)__mptr - offsetof(type,member) );}) + +#define MIN(a, b) ((a) < (b) ? (a) : (b)) +#define MAX(a, b) ((a) > (b) ? (a) : (b)) + +#define TIMESPEC_IS_SET(ts) ((ts)->tv_sec != 0 || (ts)->tv_nsec != 0) + +enum usbi_log_level { + LOG_LEVEL_DEBUG, + LOG_LEVEL_INFO, + LOG_LEVEL_WARNING, + LOG_LEVEL_ERROR, +}; + +void usbi_log(struct libusb_context *ctx, enum usbi_log_level level, + const char *function, const char *format, ...); + +#if !defined(_MSC_VER) || _MSC_VER > 1200 + +#ifdef ENABLE_LOGGING +#define _usbi_log(ctx, level, ...) usbi_log(ctx, level, __FUNCTION__, __VA_ARGS__) +#else +#define _usbi_log(ctx, level, ...) +#endif + +#ifdef ENABLE_DEBUG_LOGGING +#define usbi_dbg(...) _usbi_log(NULL, LOG_LEVEL_DEBUG, __VA_ARGS__) +#else +#define usbi_dbg(...) +#endif + +#define usbi_info(ctx, ...) _usbi_log(ctx, LOG_LEVEL_INFO, __VA_ARGS__) +#define usbi_warn(ctx, ...) _usbi_log(ctx, LOG_LEVEL_WARNING, __VA_ARGS__) +#define usbi_err(ctx, ...) _usbi_log(ctx, LOG_LEVEL_ERROR, __VA_ARGS__) + +#else /* !defined(_MSC_VER) || _MSC_VER > 1200 */ + +void usbi_log_v(struct libusb_context *ctx, enum usbi_log_level level, + const char *function, const char *format, va_list args); + +#ifdef ENABLE_LOGGING +#define LOG_BODY(ctxt, level) \ +{ \ + va_list args; \ + va_start (args, format); \ + usbi_log_v(ctxt, level, "", format, args); \ + va_end(args); \ +} +#else +#define LOG_BODY(ctxt, level) { } +#endif + +static inline void usbi_info(struct libusb_context *ctx, const char *format, + ...) + LOG_BODY(ctx,LOG_LEVEL_INFO) +static inline void usbi_warn(struct libusb_context *ctx, const char *format, + ...) + LOG_BODY(ctx,LOG_LEVEL_WARNING) +static inline void usbi_err( struct libusb_context *ctx, const char *format, + ...) + LOG_BODY(ctx,LOG_LEVEL_ERROR) + +static inline void usbi_dbg(const char *format, ...) +#ifdef ENABLE_DEBUG_LOGGING + LOG_BODY(NULL,LOG_LEVEL_DEBUG) +#else +{ } +#endif + +#endif /* !defined(_MSC_VER) || _MSC_VER > 1200 */ + +#define USBI_GET_CONTEXT(ctx) if (!(ctx)) (ctx) = usbi_default_context +#define DEVICE_CTX(dev) ((dev)->ctx) +#define HANDLE_CTX(handle) (DEVICE_CTX((handle)->dev)) +#define TRANSFER_CTX(transfer) (HANDLE_CTX((transfer)->dev_handle)) +#define ITRANSFER_CTX(transfer) \ + (TRANSFER_CTX(__USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer))) + +/* Internal abstractions for thread synchronization and poll */ +#if defined(THREADS_POSIX) +#include <os/threads_posix.h> +#elif defined(OS_WINDOWS) +#include <os/threads_windows.h> +#endif + +#if defined(OS_LINUX) || defined(OS_DARWIN) +#include <os/poll_posix.h> +#elif defined(OS_WINDOWS) +#include <os/poll_windows.h> +#endif + +extern struct libusb_context *usbi_default_context; + +struct libusb_context { + int debug; + int debug_fixed; + + /* internal control pipe, used for interrupting event handling when + * something needs to modify poll fds. */ + int ctrl_pipe[2]; + + struct list_head usb_devs; + usbi_mutex_t usb_devs_lock; + + /* A list of open handles. Backends are free to traverse this if required. + */ + struct list_head open_devs; + usbi_mutex_t open_devs_lock; + + /* this is a list of in-flight transfer handles, sorted by timeout + * expiration. URBs to timeout the soonest are placed at the beginning of + * the list, URBs that will time out later are placed after, and urbs with + * infinite timeout are always placed at the very end. */ + struct list_head flying_transfers; + usbi_mutex_t flying_transfers_lock; + + /* list of poll fds */ + struct list_head pollfds; + usbi_mutex_t pollfds_lock; + + /* a counter that is set when we want to interrupt event handling, in order + * to modify the poll fd set. and a lock to protect it. */ + unsigned int pollfd_modify; + usbi_mutex_t pollfd_modify_lock; + + /* user callbacks for pollfd changes */ + libusb_pollfd_added_cb fd_added_cb; + libusb_pollfd_removed_cb fd_removed_cb; + void *fd_cb_user_data; + + /* ensures that only one thread is handling events at any one time */ + usbi_mutex_t events_lock; + + /* used to see if there is an active thread doing event handling */ + int event_handler_active; + + /* used to wait for event completion in threads other than the one that is + * event handling */ + usbi_mutex_t event_waiters_lock; + usbi_cond_t event_waiters_cond; + +#ifdef USBI_TIMERFD_AVAILABLE + /* used for timeout handling, if supported by OS. + * this timerfd is maintained to trigger on the next pending timeout */ + int timerfd; +#endif +}; + +#ifdef USBI_TIMERFD_AVAILABLE +#define usbi_using_timerfd(ctx) ((ctx)->timerfd >= 0) +#else +#define usbi_using_timerfd(ctx) (0) +#endif + +struct libusb_device { + /* lock protects refcnt, everything else is finalized at initialization + * time */ + usbi_mutex_t lock; + int refcnt; + + struct libusb_context *ctx; + + uint8_t bus_number; + uint8_t device_address; + uint8_t num_configurations; + + struct list_head list; + unsigned long session_data; + unsigned char os_priv[0]; +}; + +struct libusb_device_handle { + /* lock protects claimed_interfaces */ + usbi_mutex_t lock; + unsigned long claimed_interfaces; + + struct list_head list; + struct libusb_device *dev; + unsigned char os_priv[0]; +}; + +#define USBI_TRANSFER_TIMED_OUT (1<<0) + +enum { + USBI_CLOCK_MONOTONIC, + USBI_CLOCK_REALTIME +}; + +/* in-memory transfer layout: + * + * 1. struct usbi_transfer + * 2. struct libusb_transfer (which includes iso packets) [variable size] + * 3. os private data [variable size] + * + * from a libusb_transfer, you can get the usbi_transfer by rewinding the + * appropriate number of bytes. + * the usbi_transfer includes the number of allocated packets, so you can + * determine the size of the transfer and hence the start and length of the + * OS-private data. + */ + +struct usbi_transfer { + int num_iso_packets; + struct list_head list; + struct timeval timeout; + int transferred; + uint8_t flags; + + /* this lock is held during libusb_submit_transfer() and + * libusb_cancel_transfer() (allowing the OS backend to prevent duplicate + * cancellation, submission-during-cancellation, etc). the OS backend + * should also take this lock in the handle_events path, to prevent the user + * cancelling the transfer from another thread while you are processing + * its completion (presumably there would be races within your OS backend + * if this were possible). */ + usbi_mutex_t lock; +}; + +#define __USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer) \ + ((struct libusb_transfer *)(((unsigned char *)(transfer)) \ + + sizeof(struct usbi_transfer))) +#define __LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer) \ + ((struct usbi_transfer *)(((unsigned char *)(transfer)) \ + - sizeof(struct usbi_transfer))) + +static inline void *usbi_transfer_get_os_priv(struct usbi_transfer *transfer) +{ + return ((unsigned char *)transfer) + sizeof(struct usbi_transfer) + + sizeof(struct libusb_transfer) + + (transfer->num_iso_packets + * sizeof(struct libusb_iso_packet_descriptor)); +} + +/* bus structures */ + +/* All standard descriptors have these 2 fields in common */ +struct usb_descriptor_header { + uint8_t bLength; + uint8_t bDescriptorType; +}; + +/* shared data and functions */ + +int usbi_io_init(struct libusb_context *ctx); +void usbi_io_exit(struct libusb_context *ctx); + +struct libusb_device *usbi_alloc_device(struct libusb_context *ctx, + unsigned long session_id); +struct libusb_device *usbi_get_device_by_session_id(struct libusb_context *ctx, + unsigned long session_id); +int usbi_sanitize_device(struct libusb_device *dev); +void usbi_handle_disconnect(struct libusb_device_handle *handle); + +int usbi_handle_transfer_completion(struct usbi_transfer *itransfer, + enum libusb_transfer_status status); +int usbi_handle_transfer_cancellation(struct usbi_transfer *transfer); + +int usbi_parse_descriptor(unsigned char *source, char *descriptor, void *dest, + int host_endian); +int usbi_get_config_index_by_value(struct libusb_device *dev, + uint8_t bConfigurationValue, int *idx); + +/* polling */ + +struct usbi_pollfd { + /* must come first */ + struct libusb_pollfd pollfd; + + struct list_head list; +}; + +int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events); +void usbi_remove_pollfd(struct libusb_context *ctx, int fd); +void usbi_fd_notification(struct libusb_context *ctx); + +/* device discovery */ + +/* we traverse usbfs without knowing how many devices we are going to find. + * so we create this discovered_devs model which is similar to a linked-list + * which grows when required. it can be freed once discovery has completed, + * eliminating the need for a list node in the libusb_device structure + * itself. */ +struct discovered_devs { + size_t len; + size_t capacity; + struct libusb_device *devices[0]; +}; + +struct discovered_devs *discovered_devs_append( + struct discovered_devs *discdevs, struct libusb_device *dev); + +/* OS abstraction */ + +/* This is the interface that OS backends need to implement. + * All fields are mandatory, except ones explicitly noted as optional. */ +struct usbi_os_backend { + /* A human-readable name for your backend, e.g. "Linux usbfs" */ + const char *name; + + /* Perform initialization of your backend. You might use this function + * to determine specific capabilities of the system, allocate required + * data structures for later, etc. + * + * This function is called when a libusb user initializes the library + * prior to use. + * + * Return 0 on success, or a LIBUSB_ERROR code on failure. + */ + int (*init)(struct libusb_context *ctx); + + /* Deinitialization. Optional. This function should destroy anything + * that was set up by init. + * + * This function is called when the user deinitializes the library. + */ + void (*exit)(void); + + /* Enumerate all the USB devices on the system, returning them in a list + * of discovered devices. + * + * Your implementation should enumerate all devices on the system, + * regardless of whether they have been seen before or not. + * + * When you have found a device, compute a session ID for it. The session + * ID should uniquely represent that particular device for that particular + * connection session since boot (i.e. if you disconnect and reconnect a + * device immediately after, it should be assigned a different session ID). + * If your OS cannot provide a unique session ID as described above, + * presenting a session ID of (bus_number << 8 | device_address) should + * be sufficient. Bus numbers and device addresses wrap and get reused, + * but that is an unlikely case. + * + * After computing a session ID for a device, call + * usbi_get_device_by_session_id(). This function checks if libusb already + * knows about the device, and if so, it provides you with a libusb_device + * structure for it. + * + * If usbi_get_device_by_session_id() returns NULL, it is time to allocate + * a new device structure for the device. Call usbi_alloc_device() to + * obtain a new libusb_device structure with reference count 1. Populate + * the bus_number and device_address attributes of the new device, and + * perform any other internal backend initialization you need to do. At + * this point, you should be ready to provide device descriptors and so + * on through the get_*_descriptor functions. Finally, call + * usbi_sanitize_device() to perform some final sanity checks on the + * device. Assuming all of the above succeeded, we can now continue. + * If any of the above failed, remember to unreference the device that + * was returned by usbi_alloc_device(). + * + * At this stage we have a populated libusb_device structure (either one + * that was found earlier, or one that we have just allocated and + * populated). This can now be added to the discovered devices list + * using discovered_devs_append(). Note that discovered_devs_append() + * may reallocate the list, returning a new location for it, and also + * note that reallocation can fail. Your backend should handle these + * error conditions appropriately. + * + * This function should not generate any bus I/O and should not block. + * If I/O is required (e.g. reading the active configuration value), it is + * OK to ignore these suggestions :) + * + * This function is executed when the user wishes to retrieve a list + * of USB devices connected to the system. + * + * Return 0 on success, or a LIBUSB_ERROR code on failure. + */ + int (*get_device_list)(struct libusb_context *ctx, + struct discovered_devs **discdevs); + + /* Open a device for I/O and other USB operations. The device handle + * is preallocated for you, you can retrieve the device in question + * through handle->dev. + * + * Your backend should allocate any internal resources required for I/O + * and other operations so that those operations can happen (hopefully) + * without hiccup. This is also a good place to inform libusb that it + * should monitor certain file descriptors related to this device - + * see the usbi_add_pollfd() function. + * + * This function should not generate any bus I/O and should not block. + * + * This function is called when the user attempts to obtain a device + * handle for a device. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_ACCESS if the user has insufficient permissions + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since + * discovery + * - another LIBUSB_ERROR code on other failure + * + * Do not worry about freeing the handle on failed open, the upper layers + * do this for you. + */ + int (*open)(struct libusb_device_handle *handle); + + /* Close a device such that the handle cannot be used again. Your backend + * should destroy any resources that were allocated in the open path. + * This may also be a good place to call usbi_remove_pollfd() to inform + * libusb of any file descriptors associated with this device that should + * no longer be monitored. + * + * This function is called when the user closes a device handle. + */ + void (*close)(struct libusb_device_handle *handle); + + /* Retrieve the device descriptor from a device. + * + * The descriptor should be retrieved from memory, NOT via bus I/O to the + * device. This means that you may have to cache it in a private structure + * during get_device_list enumeration. Alternatively, you may be able + * to retrieve it from a kernel interface (some Linux setups can do this) + * still without generating bus I/O. + * + * This function is expected to write DEVICE_DESC_LENGTH (18) bytes into + * buffer, which is guaranteed to be big enough. + * + * This function is called when sanity-checking a device before adding + * it to the list of discovered devices, and also when the user requests + * to read the device descriptor. + * + * This function is expected to return the descriptor in bus-endian format + * (LE). If it returns the multi-byte values in host-endian format, + * set the host_endian output parameter to "1". + * + * Return 0 on success or a LIBUSB_ERROR code on failure. + */ + int (*get_device_descriptor)(struct libusb_device *device, + unsigned char *buffer, int *host_endian); + + /* Get the ACTIVE configuration descriptor for a device. + * + * The descriptor should be retrieved from memory, NOT via bus I/O to the + * device. This means that you may have to cache it in a private structure + * during get_device_list enumeration. You may also have to keep track + * of which configuration is active when the user changes it. + * + * This function is expected to write len bytes of data into buffer, which + * is guaranteed to be big enough. If you can only do a partial write, + * return an error code. + * + * This function is expected to return the descriptor in bus-endian format + * (LE). If it returns the multi-byte values in host-endian format, + * set the host_endian output parameter to "1". + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if the device is in unconfigured state + * - another LIBUSB_ERROR code on other failure + */ + int (*get_active_config_descriptor)(struct libusb_device *device, + unsigned char *buffer, size_t len, int *host_endian); + + /* Get a specific configuration descriptor for a device. + * + * The descriptor should be retrieved from memory, NOT via bus I/O to the + * device. This means that you may have to cache it in a private structure + * during get_device_list enumeration. + * + * The requested descriptor is expressed as a zero-based index (i.e. 0 + * indicates that we are requesting the first descriptor). The index does + * not (necessarily) equal the bConfigurationValue of the configuration + * being requested. + * + * This function is expected to write len bytes of data into buffer, which + * is guaranteed to be big enough. If you can only do a partial write, + * return an error code. + * + * This function is expected to return the descriptor in bus-endian format + * (LE). If it returns the multi-byte values in host-endian format, + * set the host_endian output parameter to "1". + * + * Return 0 on success or a LIBUSB_ERROR code on failure. + */ + int (*get_config_descriptor)(struct libusb_device *device, + uint8_t config_index, unsigned char *buffer, size_t len, + int *host_endian); + + /* Get the bConfigurationValue for the active configuration for a device. + * Optional. This should only be implemented if you can retrieve it from + * cache (don't generate I/O). + * + * If you cannot retrieve this from cache, either do not implement this + * function, or return LIBUSB_ERROR_NOT_SUPPORTED. This will cause + * libusb to retrieve the information through a standard control transfer. + * + * This function must be non-blocking. + * Return: + * - 0 on success + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - LIBUSB_ERROR_NOT_SUPPORTED if the value cannot be retrieved without + * blocking + * - another LIBUSB_ERROR code on other failure. + */ + int (*get_configuration)(struct libusb_device_handle *handle, int *config); + + /* Set the active configuration for a device. + * + * A configuration value of -1 should put the device in unconfigured state. + * + * This function can block. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if the configuration does not exist + * - LIBUSB_ERROR_BUSY if interfaces are currently claimed (and hence + * configuration cannot be changed) + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure. + */ + int (*set_configuration)(struct libusb_device_handle *handle, int config); + + /* Claim an interface. When claimed, the application can then perform + * I/O to an interface's endpoints. + * + * This function should not generate any bus I/O and should not block. + * Interface claiming is a logical operation that simply ensures that + * no other drivers/applications are using the interface, and after + * claiming, no other drivers/applicatiosn can use the interface because + * we now "own" it. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if the interface does not exist + * - LIBUSB_ERROR_BUSY if the interface is in use by another driver/app + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*claim_interface)(struct libusb_device_handle *handle, int interface_number); + + /* Release a previously claimed interface. + * + * This function should also generate a SET_INTERFACE control request, + * resetting the alternate setting of that interface to 0. It's OK for + * this function to block as a result. + * + * You will only ever be asked to release an interface which was + * successfully claimed earlier. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*release_interface)(struct libusb_device_handle *handle, int interface_number); + + /* Set the alternate setting for an interface. + * + * You will only ever be asked to set the alternate setting for an + * interface which was successfully claimed earlier. + * + * It's OK for this function to block. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if the alternate setting does not exist + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*set_interface_altsetting)(struct libusb_device_handle *handle, + int interface_number, int altsetting); + + /* Clear a halt/stall condition on an endpoint. + * + * It's OK for this function to block. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if the endpoint does not exist + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*clear_halt)(struct libusb_device_handle *handle, + unsigned char endpoint); + + /* Perform a USB port reset to reinitialize a device. + * + * If possible, the handle should still be usable after the reset + * completes, assuming that the device descriptors did not change during + * reset and all previous interface state can be restored. + * + * If something changes, or you cannot easily locate/verify the resetted + * device, return LIBUSB_ERROR_NOT_FOUND. This prompts the application + * to close the old handle and re-enumerate the device. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if re-enumeration is required, or if the device + * has been disconnected since it was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*reset_device)(struct libusb_device_handle *handle); + + /* Determine if a kernel driver is active on an interface. Optional. + * + * The presence of a kernel driver on an interface indicates that any + * calls to claim_interface would fail with the LIBUSB_ERROR_BUSY code. + * + * Return: + * - 0 if no driver is active + * - 1 if a driver is active + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*kernel_driver_active)(struct libusb_device_handle *handle, + int interface_number); + + /* Detach a kernel driver from an interface. Optional. + * + * After detaching a kernel driver, the interface should be available + * for claim. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active + * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - another LIBUSB_ERROR code on other failure + */ + int (*detach_kernel_driver)(struct libusb_device_handle *handle, + int interface_number); + + /* Attach a kernel driver to an interface. Optional. + * + * Reattach a kernel driver to the device. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NOT_FOUND if no kernel driver was active + * - LIBUSB_ERROR_INVALID_PARAM if the interface does not exist + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected since it + * was opened + * - LIBUSB_ERROR_BUSY if a program or driver has claimed the interface, + * preventing reattachment + * - another LIBUSB_ERROR code on other failure + */ + int (*attach_kernel_driver)(struct libusb_device_handle *handle, + int interface_number); + + /* Destroy a device. Optional. + * + * This function is called when the last reference to a device is + * destroyed. It should free any resources allocated in the get_device_list + * path. + */ + void (*destroy_device)(struct libusb_device *dev); + + /* Submit a transfer. Your implementation should take the transfer, + * morph it into whatever form your platform requires, and submit it + * asynchronously. + * + * This function must not block. + * + * Return: + * - 0 on success + * - LIBUSB_ERROR_NO_DEVICE if the device has been disconnected + * - another LIBUSB_ERROR code on other failure + */ + int (*submit_transfer)(struct usbi_transfer *itransfer); + + /* Cancel a previously submitted transfer. + * + * This function must not block. The transfer cancellation must complete + * later, resulting in a call to usbi_handle_transfer_cancellation() + * from the context of handle_events. + */ + int (*cancel_transfer)(struct usbi_transfer *itransfer); + + /* Clear a transfer as if it has completed or cancelled, but do not + * report any completion/cancellation to the library. You should free + * all private data from the transfer as if you were just about to report + * completion or cancellation. + * + * This function might seem a bit out of place. It is used when libusb + * detects a disconnected device - it calls this function for all pending + * transfers before reporting completion (with the disconnect code) to + * the user. Maybe we can improve upon this internal interface in future. + */ + void (*clear_transfer_priv)(struct usbi_transfer *itransfer); + + /* Handle any pending events. This involves monitoring any active + * transfers and processing their completion or cancellation. + * + * The function is passed an array of pollfd structures (size nfds) + * as a result of the poll() system call. The num_ready parameter + * indicates the number of file descriptors that have reported events + * (i.e. the poll() return value). This should be enough information + * for you to determine which actions need to be taken on the currently + * active transfers. + * + * For any cancelled transfers, call usbi_handle_transfer_cancellation(). + * For completed transfers, call usbi_handle_transfer_completion(). + * For control/bulk/interrupt transfers, populate the "transferred" + * element of the appropriate usbi_transfer structure before calling the + * above functions. For isochronous transfers, populate the status and + * transferred fields of the iso packet descriptors of the transfer. + * + * This function should also be able to detect disconnection of the + * device, reporting that situation with usbi_handle_disconnect(). + * + * When processing an event related to a transfer, you probably want to + * take usbi_transfer.lock to prevent races. See the documentation for + * the usbi_transfer structure. + * + * Return 0 on success, or a LIBUSB_ERROR code on failure. + */ + int (*handle_events)(struct libusb_context *ctx, + struct pollfd *fds, nfds_t nfds, int num_ready); + + /* Get time from specified clock. At least two clocks must be implemented + by the backend: USBI_CLOCK_REALTIME, and USBI_CLOCK_MONOTONIC. + + Description of clocks: + USBI_CLOCK_REALTIME : clock returns time since system epoch. + USBI_CLOCK_MONOTONIC: clock returns time since unspecified start + time (usually boot). + */ + int (*clock_gettime)(int clkid, struct timespec *tp); + +#ifdef USBI_TIMERFD_AVAILABLE + /* clock ID of the clock that should be used for timerfd */ + clockid_t (*get_timerfd_clockid)(void); +#endif + + /* Number of bytes to reserve for per-device private backend data. + * This private data area is accessible through the "os_priv" field of + * struct libusb_device. */ + size_t device_priv_size; + + /* Number of bytes to reserve for per-handle private backend data. + * This private data area is accessible through the "os_priv" field of + * struct libusb_device. */ + size_t device_handle_priv_size; + + /* Number of bytes to reserve for per-transfer private backend data. + * This private data area is accessible by calling + * usbi_transfer_get_os_priv() on the appropriate usbi_transfer instance. + */ + size_t transfer_priv_size; + + /* Mumber of additional bytes for os_priv for each iso packet. + * Can your backend use this? */ + /* FIXME: linux can't use this any more. if other OS's cannot either, + * then remove this */ + size_t add_iso_packet_size; +}; + +extern const struct usbi_os_backend * const usbi_backend; + +extern const struct usbi_os_backend linux_usbfs_backend; +extern const struct usbi_os_backend darwin_backend; +extern const struct usbi_os_backend windows_backend; + +#endif + |