LIBUSB20(3) BSD Library Functions Manual LIBUSB20(3)NAMElibusb20 — USB access library
LIBRARY
USB access library (libusb -lusb)
SYNOPSIS
#include <libusb20.h>
int
libusb20_tr_close(struct libusb20_transfer *xfer);
int
libusb20_tr_open(struct libusb20_transfer *xfer, uint32_t max_buf_size,
uint32_t max_frame_count, uint8_t ep_no);
struct libusb20_transfer*
libusb20_tr_get_pointer(struct libusb20_device *pdev, uint16_t tr_index);
uint16_t
libusb20_tr_get_time_complete(struct libusb20_transfer *xfer);
uint32_t
libusb20_tr_get_actual_frames(struct libusb20_transfer *xfer);
uint32_t
libusb20_tr_get_actual_length(struct libusb20_transfer *xfer);
uint32_t
libusb20_tr_get_max_frames(struct libusb20_transfer *xfer);
uint32_t
libusb20_tr_get_max_packet_length(struct libusb20_transfer *xfer);
uint32_t
libusb20_tr_get_max_total_length(struct libusb20_transfer *xfer);
uint8_t
libusb20_tr_get_status(struct libusb20_transfer *xfer);
uint8_t
libusb20_tr_pending(struct libusb20_transfer *xfer);
void
libusb20_tr_callback_wrapper(struct libusb20_transfer *xfer);
void
libusb20_tr_clear_stall_sync(struct libusb20_transfer *xfer);
void
libusb20_tr_drain(struct libusb20_transfer *xfer);
void
libusb20_tr_set_buffer(struct libusb20_transfer *xfer, void *buffer,
uint16_t fr_index);
void
libusb20_tr_set_callback(struct libusb20_transfer *xfer,
libusb20_tr_callback_t *cb);
void
libusb20_tr_set_flags(struct libusb20_transfer *xfer, uint8_t flags);
uint32_t
libusb20_tr_get_length(struct libusb20_transfer *xfer,
uint16_t fr_index);
void
libusb20_tr_set_length(struct libusb20_transfer *xfer, uint32_t length,
uint16_t fr_index);
void
libusb20_tr_set_priv_sc0(struct libusb20_transfer *xfer, void *sc0);
void
libusb20_tr_set_priv_sc1(struct libusb20_transfer *xfer, void *sc1);
void
libusb20_tr_set_timeout(struct libusb20_transfer *xfer,
uint32_t timeout);
void
libusb20_tr_set_total_frames(struct libusb20_transfer *xfer,
uint32_t nframes);
void
libusb20_tr_setup_bulk(struct libusb20_transfer *xfer, void *pbuf,
uint32_t length, uint32_t timeout);
void
libusb20_tr_setup_control(struct libusb20_transfer *xfer, void *psetup,
void *pbuf, uint32_t timeout);
void
libusb20_tr_setup_intr(struct libusb20_transfer *xfer, void *pbuf,
uint32_t length, uint32_t timeout);
void
libusb20_tr_setup_isoc(struct libusb20_transfer *xfer, void *pbuf,
uint32_t length, uint61_t fr_index);
uint8_t
libusb20_tr_bulk_intr_sync(struct libusb20_transfer *xfer, void *pbuf,
uint32_t length, uint32_t *pactlen, uint32_t timeout);
void
libusb20_tr_start(struct libusb20_transfer *xfer);
void
libusb20_tr_stop(struct libusb20_transfer *xfer);
void
libusb20_tr_submit(struct libusb20_transfer *xfer);
void *
libusb20_tr_get_priv_sc0(struct libusb20_transfer *xfer);
void *
libusb20_tr_get_priv_sc1(struct libusb20_transfer *xfer);
const char *
libusb20_dev_get_backend_name(struct libusb20_device *);
int
libusb20_dev_get_info(struct libusb20_device *pdev,
struct usb_device_info *pinfo);
int
libusb20_dev_get_iface_desc(struct libusb20_device *pdev,
uint8_t iface_index, char *buf, uint8_t len);
const char *
libusb20_dev_get_desc(struct libusb20_device *pdev);
int
libusb20_dev_close(struct libusb20_device *pdev);
int
libusb20_dev_detach_kernel_driver(struct libusb20_device *pdev,
uint8_t iface_index);
int
libusb20_dev_set_config_index(struct libusb20_device *pdev,
uint8_t configIndex);
int
libusb20_dev_get_debug(struct libusb20_device *pdev);
int
libusb20_dev_get_fd(struct libusb20_device *pdev);
int
libusb20_dev_kernel_driver_active(struct libusb20_device *pdev,
uint8_t iface_index);
int
libusb20_dev_open(struct libusb20_device *pdev, uint16_t transfer_max);
int
libusb20_dev_process(struct libusb20_device *pdev);
int
libusb20_dev_request_sync(struct libusb20_device *pdev,
struct LIBUSB20_CONTROL_SETUP_DECODED *setup, void *data,
uint16_t *pactlen, uint32_t timeout, uint8_t flags);
int
libusb20_dev_req_string_sync(struct libusb20_device *pdev, uint8_t index,
uint16_t langid, void *ptr, uint16_t len);
int
libusb20_dev_req_string_simple_sync(struct libusb20_device *pdev,
uint8_t index, void *ptr, uint16_t len);
int
libusb20_dev_reset(struct libusb20_device *pdev);
int
libusb20_dev_check_connected(struct libusb20_device *pdev);
int
libusb20_dev_set_power_mode(struct libusb20_device *pdev,
uint8_t power_mode);
uint8_t
libusb20_dev_get_power_mode(struct libusb20_device *pdev);
int
libusb20_dev_set_alt_index(struct libusb20_device *pdev,
uint8_t iface_index, uint8_t alt_index);
struct LIBUSB20_DEVICE_DESC_DECODED *
libusb20_dev_get_device_desc(struct libusb20_device *pdev);
struct libusb20_config *
libusb20_dev_alloc_config(struct libusb20_device *pdev,
uint8_t config_index);
struct libusb20_device *
libusb20_dev_alloc(void);
uint8_t
libusb20_dev_get_address(struct libusb20_device *pdev);
uint8_t
libusb20_dev_get_bus_number(struct libusb20_device *pdev);
uint8_t
libusb20_dev_get_mode(struct libusb20_device *pdev);
uint8_t
libusb20_dev_get_speed(struct libusb20_device *pdev);
uint8_t
libusb20_dev_get_config_index(struct libusb20_device *pdev);
void
libusb20_dev_free(struct libusb20_device *pdev);
void
libusb20_dev_set_debug(struct libusb20_device *pdev, int debug);
void
libusb20_dev_wait_process(struct libusb20_device *pdev, int timeout);
int
libusb20_be_get_template(struct libusb20_backend *pbe, int *ptemp);
int
libusb20_be_set_template(struct libusb20_backend *pbe, int temp);
int
libusb20_be_get_dev_quirk(struct libusb20_backend *pber, uint16_t index,
struct libusb20_quirk *pq);
int
libusb20_be_get_quirk_name(struct libusb20_backend *pbe, uint16_t index,
struct libusb20_quirk *pq);
int
libusb20_be_add_dev_quirk(struct libusb20_backend *pbe,
struct libusb20_quirk *pq);
int
libusb20_be_remove_dev_quirk(struct libusb20_backend *pbe,
struct libusb20_quirk *pq);
struct libusb20_backend *
libusb20_be_alloc_default(void);
struct libusb20_backend *
libusb20_be_alloc_freebsd(void);
struct libusb20_backend *
libusb20_be_alloc_linux(void);
struct libusb20_device *
libusb20_be_device_foreach(struct libusb20_backend *pbe,
struct libusb20_device *pdev);
void
libusb20_be_dequeue_device(struct libusb20_backend *pbe,
struct libusb20_device *pdev);
void
libusb20_be_enqueue_device(struct libusb20_backend *pbe,
struct libusb20_device *pdev);
void
libusb20_be_free(struct libusb20_backend *pbe);
uint8_t
libusb20_me_get_1(const struct libusb20_me_struct *me, uint16_t off);
uint16_t
libusb20_me_get_2(const struct libusb20_me_struct *me, uint16_t off);
uint16_t
libusb20_me_encode(void *pdata, uint16_t len, const void *pdecoded);
uint16_t
libusb20_me_decode(const void *pdata, uint16_t len, void *pdecoded);
const uint8_t *
libusb20_desc_foreach(const struct libusb20_me_struct *me,
const uint8_t *pdesc);
DESCRIPTION
The libusb20 library implements functions to be able to easily access and
control USB through the USB file system interface. The libusb20 inter‐
faces are specific to the FreeBSD usb stack and are not available on
other operating systems, portable applications should consider using
libusb(3).
USB TRANSFER OPERATIONSlibusb20_tr_close() will release all kernel resources associated with an
USB xfer. This function returns zero upon success. Non-zero return val‐
ues indicate a LIBUSB20_ERROR value.
libusb20_tr_open() will allocate kernel buffer resources according to
max_buf_size and max_frame_count associated with an USB pxfer and bind
the transfer to the specified ep_no. max_buf_size is the minimum buffer
size which the data transport layer has to support. If max_buf_size is
zero, the libusb20 library will use wMaxPacketSize to compute the buffer
size. This can be useful for isochronous transfers. The actual buffer
size can be greater than max_buf_size and is returned by
libusb20_tr_get_max_total_length(). This function returns zero upon suc‐
cess. Non-zero return values indicate a LIBUSB20_ERROR value.
libusb20_tr_get_pointer() will return a pointer to the allocated USB
transfer according to the pdev and tr_index arguments. This function
returns NULL in case of failure.
libusb20_tr_get_time_complete() will return the completion time of an USB
transfer in millisecond units. This function is most useful for
isochronous USB transfers when doing echo cancelling.
libusb20_tr_get_actual_frames() will return the actual number of USB
frames after an USB transfer completed. A value of zero means that no
data was transferred.
libusb20_tr_get_actual_length() will return the sum of the actual length
for all transferred USB frames for the given USB transfer.
libusb20_tr_get_max_frames() will return the maximum number of USB frames
that were allocated when an USB transfer was setup for the given USB
transfer.
libusb20_tr_get_max_packet_length() will return the maximum packet length
in bytes associated with the given USB transfer. The packet length can
be used round up buffer sizes so that short USB packets are avoided for
proxy buffers.
libusb20_tr_get_max_total_length() function will return the maximum value
for the data length sum of all USB frames associated with an USB trans‐
fer. In case of control transfers the value returned does not include
the length of the SETUP packet, 8 bytes, which is part of frame zero.
The returned value of this function is always aligned to the maximum
packet size, wMaxPacketSize, of the endpoint which the USB transfer is
bound to.
libusb20_tr_get_status() will return the status of an USB transfer. Sta‐
tus values are defined by a set of LIBUSB20_TRANSFER_XXX enums.
libusb20_tr_pending() will return non-zero if the given USB transfer is
pending for completion. Else this function returns zero.
libusb20_tr_callback_wrapper() This is an internal function used to wrap
asynchronous USB callbacks.
libusb20_tr_clear_stall_sync() This is an internal function used to syn‐
chronously clear the stall on the given USB transfer. Please see the USB
specification for more information on stall clearing. If the given USB
transfer is pending when this function is called, the USB transfer will
complete with an error after that this function has been called.
libusb20_tr_drain() will stop the given USB transfer and will not return
until the USB transfer has been stopped in hardware.
libusb20_tr_set_buffer() is used to set the buffer pointer for the given
USB transfer and fr_index. Typically the frame index is zero.
libusb20_tr_set_callback() is used to set the USB callback for asynchro‐
nous USB transfers. The callback type is defined by libusb20_tr_call‐
back_t.
libusb20_tr_set_flags() is used to set various USB flags for the given
USB transfer.
LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK
Report a short frame as error.
LIBUSB20_TRANSFER_MULTI_SHORT_NOT_OK
Multiple short frames are not allowed.
LIBUSB20_TRANSFER_FORCE_SHORT
All transmitted frames are short terminated.
LIBUSB20_TRANSFER_DO_CLEAR_STALL
Will do a clear-stall before starting the transfer.
libusb20_tr_get_length() returns the length of the given USB frame by
index. After an USB transfer is complete the USB frame length will get
updated to the actual transferred length.
libusb20_tr_set_length() sets the length of the given USB frame by index.
libusb20_tr_set_priv_sc0() sets private driver pointer number zero.
libusb20_tr_set_priv_sc1() sets private driver pointer number one.
libusb20_tr_set_timeout() sets the timeout for the given USB transfer. A
timeout value of zero means no timeout. The timeout is given in mil‐
liseconds.
libusb20_tr_set_total_frames() sets the total number of frames that
should be executed when the USB transfer is submitted. The total number
of USB frames must be less than the maximum number of USB frames associ‐
ated with the given USB transfer.
libusb20_tr_setup_bulk() is a helper function for setting up a single
frame USB BULK transfer.
libusb20_tr_setup_control() is a helper function for setting up a single
or dual frame USB CONTROL transfer depending on the control transfer
length.
libusb20_tr_setup_intr() is a helper function for setting up a single
frame USB INTERRUPT transfer.
libusb20_tr_setup_isoc() is a helper function for setting up a multi
frame USB ISOCHRONOUS transfer.
libusb20_tr_bulk_intr_sync() will perform a synchronous BULK or INTERRUPT
transfer having length given by the length argument and buffer pointer
given by the pbuf argument on the USB transfer given by the xfer argu‐
ment. If the pactlen argument is non-NULL the actual transfer length
will be stored at the given pointer destination. If the timeout argument
is non-zero the transfer will timeout after the given value in millisec‐
onds. This function does not change the transfer flags, like short
packet not ok. This function returns zero on success else a
LIBUSB20_TRANSFER_XXX value is returned.
libusb20_tr_start() will get the USB transfer started, if not already
started. This function will not get the transfer queued in hardware.
This function is non-blocking.
libusb20_tr_stop() will get the USB transfer stopped, if not already
stopped. This function is non-blocking, which means that the actual stop
can happen after the return of this function.
libusb20_tr_submit() will get the USB transfer queued in hardware.
libusb20_tr_get_priv_sc0() returns private driver pointer number zero
associated with an USB transfer.
libusb20_tr_get_priv_sc1() returns private driver pointer number one
associated with an USB transfer.
USB DEVICE OPERATIONSlibusb20_dev_get_backend_name() returns a zero terminated string describ‐
ing the backend used.
libusb20_dev_get_info() retrives the BSD specific usb_device_info struc‐
ture into the memory location given by pinfo. The USB device given by
pdev must be opened before this function will succeed. This function
returns zero on success else a LIBUSB20_ERROR value is returned.
libusb20_dev_get_iface_desc() retrieves the kernel interface description
for the given USB iface_index. The format of the USB interface descrip‐
tion is: "drivername<unit>: <description>" The description string is
always zero terminated. A zero length string is written in case no
driver is attached to the given interface. The USB device given by pdev
must be opened before this function will succeed. This function returns
zero on success else a LIBUSB20_ERROR value is returned.
libusb20_dev_get_desc() returns a zero terminated string describing the
given USB device. The format of the string is: "drivername<unit>:
<description>"
libusb20_dev_close() will close the given USB device. This function
returns zero on success else a LIBUSB20_ERROR value is returned.
libusb20_dev_detach_kernel_driver() will try to detach the kernel driver
for the USB interface given by iface_index. This function returns zero
on success else a LIBUSB20_ERROR value is returned.
libusb20_dev_set_config_index() will try to set the configuration index
on an USB device. The first configuration index is zero. The un-config‐
ure index is 255. This function returns zero on success else a
LIBUSB20_ERROR value is returned.
libusb20_dev_get_debug() returns the debug level of an USB device.
libusb20_dev_get_fd() returns the file descriptor of the given USB
device. A negative value is returned when no file descriptor is present.
The file descriptor can be used for polling purposes.
libusb20_dev_kernel_driver_active() returns a non-zero value if a kernel
driver is active on the given USB interface. Else zero is returned.
libusb20_dev_open() opens an USB device so that setting up USB transfers
becomes possible. The number of USB transfers can be zero which means
only control transfers are allowed. This function returns zero on suc‐
cess else a LIBUSB20_ERROR value is returned. A return value of
LIBUSB20_ERROR_BUSY means that the device is already opened.
libusb20_dev_process() is called to sync kernel USB transfers with user‐
land USB transfers. This function returns zero on success else a
LIBUSB20_ERROR value is returned typically indicating that the given USB
device has been detached.
libusb20_dev_request_sync() will perform a synchronous control request on
the given USB device. Before this call will succeed the USB device must
be opened. setup is a pointer to a decoded and host endian SETUP packet.
data is a pointer to a data transfer buffer associated with the control
transaction. This argument can be NULL. pactlen is a pointer to a vari‐
able that will hold the actual transfer length after the control transac‐
tion is complete. timeout is the transaction timeout given in millisec‐
onds. A timeout of zero means no timeout. flags is used to specify
transaction flags, for example LIBUSB20_TRANSFER_SINGLE_SHORT_NOT_OK.
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
libusb20_dev_req_string_sync() will synchronously request an USB string
by language ID and string index into the given buffer limited by a maxi‐
mum length. This function returns zero on success else a LIBUSB20_ERROR
value is returned.
libusb20_dev_req_string_simple_sync() will synchronously request an USB
string using the default language ID and convert the string into ASCII
before storing the string into the given buffer limited by a maximum
length which includes the terminating zero. This function returns zero
on success else a LIBUSB20_ERROR value is returned.
libusb20_dev_reset() will try to BUS reset the given USB device and
restore the last set USB configuration. This function returns zero on
success else a LIBUSB20_ERROR value is returned.
libusb20_dev_check_connected() will check if an opened USB device is
still connected. This function returns zero if the device is still con‐
nected else a LIBUSB20_ERROR value is returned.
libusb20_dev_set_power_mode() sets the power mode of the USB device.
Valid power modes:
LIBUSB20_POWER_OFF
LIBUSB20_POWER_ON
LIBUSB20_POWER_SAVE
LIBUSB20_POWER_SUSPEND
LIBUSB20_POWER_RESUME
This function returns zero on success else a LIBUSB20_ERROR value is
returned.
libusb20_dev_get_power_mode() returns the currently selected power mode
for the given USB device.
libusb20_dev_set_alt_index() will try to set the given alternate index
for the given USB interface index. This function returns zero on success
else a LIBUSB20_ERROR value is returned.
libusb20_dev_get_device_desc() returns a pointer to the decoded and host
endian version of the device descriptor. The USB device need not be
opened when calling this function.
libusb20_dev_alloc_config() will read out and decode the USB config
descriptor for the given USB device and config index. This function
returns a pointer to the decoded configuration which must eventually be
passed to free(). NULL is returned in case of failure.
libusb20_dev_alloc() is an internal function to allocate a new USB
device.
libusb20_dev_get_address() returns the internal and not necessarily the
real hardware address of the given USB device.
libusb20_dev_get_bus_number() returns the internal bus number which the
given USB device belongs to.
libusb20_dev_get_mode() returns the current operation mode of the USB
entity. Valid return values are:
LIBUSB20_MODE_HOST
LIBUSB20_MODE_DEVICE
libusb20_dev_get_speed() returns the current speed of the given USB
device.
LIBUSB20_SPEED_UNKNOWN
LIBUSB20_SPEED_LOW
LIBUSB20_SPEED_FULL
LIBUSB20_SPEED_HIGH
LIBUSB20_SPEED_VARIABLE
LIBUSB20_SPEED_SUPER
libusb20_dev_get_config_index() This function returns the currently
select config index for the given USB device.
libusb20_dev_free() will free the given USB device and all associated USB
transfers.
libusb20_dev_set_debug() will set the debug level for the given USB
device.
libusb20_dev_wait_process() function will wait until a pending USB trans‐
fer has completed on the given USB device. A timeout value can be speci‐
fied which is passed on to the poll(2) function.
USB BACKEND OPERATIONSlibusb20_be_get_template() will return the currently selected global USB
device side mode template into the integer pointer ptemp. This function
returns zero on success else a LIBUSB20_ERROR value is returned.
libusb20_be_set_template() will set the global USB device side mode tem‐
plate to temp. The new template is not activated until after the next
USB enumeration. The template number decides how the USB device will
present itself to the USB Host, like Mass Storage Device, USB Ethernet
Device. Also see the usb2_template(4) module. This function returns zero
on success else a LIBUSB20_ERROR value is returned.
libusb20_be_get_dev_quirk() This function will return the device quirk
according to index into the libusb20_quirk structure pointed to by pq.
This function returns zero on success else a LIBUSB20_ERROR value is
returned. If the given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is
returned.
libusb20_be_get_quirk_name() will return the quirk name according to
index into the libusb20_quirk structure pointed to by pq. This function
returns zero on success else a LIBUSB20_ERROR value is returned. If the
given quirk does not exist LIBUSB20_ERROR_NOT_FOUND is returned.
libusb20_be_add_dev_quirk() will add the libusb20_quirk structure pointed
to by the pq argument into the device quirk list. This function returns
zero on success else a LIBUSB20_ERROR value is returned. If the given
quirk cannot be added LIBUSB20_ERROR_NO_MEM is returned.
libusb20_be_remove_dev_quirk() will remove the quirk matching the
libusb20_quirk structure pointed to by the pq argument from the device
quirk list. This function returns zero on success else a LIBUSB20_ERROR
value is returned. If the given quirk does not exist
LIBUSB20_ERROR_NOT_FOUND is returned.
libusb20_be_alloc_default()libusb20_be_alloc_freebsd()libusb20_be_alloc_linux() These functions are used to allocate a specific
USB backend or the operating system default USB backend. Allocating a
backend is a way to scan for currently present USB devices.
libusb20_be_device_foreach() is used to iterate USB devices present in a
USB backend. The starting value of pdev is NULL. This function returns
the next USB device in the list. If NULL is returned the end of the USB
device list has been reached.
libusb20_be_dequeue_device() will dequeue the given USB device pointer
from the backend USB device list. Dequeued USB devices will not be freed
when the backend is freed.
libusb20_be_enqueue_device() This function will enqueue the given USB
device pointer in the backend USB device list. Enqueued USB devices will
get freed when the backend is freed.
libusb20_be_free() will free the given backend and all USB devices in its
device list.
USB DESCRIPTOR PARSING
libusb20_me_get_1(pie, offset) This function will return a byte at the
given byte offset of a message entity. This function is safe against
invalid offsets.
libusb20_me_get_2(pie, offset) This function will return a little endian
16-bit value at the given byte offset of a message entity. This function
is safe against invalid offsets.
libusb20_me_encode(pbuf, len, pdecoded) This function will encode a so-
called *DECODED structure into binary format. The total encoded length
that will fit in the given buffer is returned. If the buffer pointer is
NULL no data will be written to the buffer location.
libusb20_me_decode(pbuf, len, pdecoded) This function will decode a
binary structure into a so-called *DECODED structure. The total decoded
length is returned. The buffer pointer cannot be NULL.
FILES
/dev/usb
SEE ALSOusb(4), libusb(3), usbconfig(8)HISTORY
Some parts of the libusb20 API derives from the libusb project at source‐
forge.
BSD October 14, 2010 BSD