Tribblix: manual page: usb_get_dev

USB_GET_DEV_DATA(9F) Kernel Functions for Drivers USB_GET_DEV_DATA(9F)

NAME

usb_get_dev_data, usb_free_dev_data, usb_free_descr_tree,
usb_print_descr_tree - Retrieve device configuration information

SYNOPSIS

#include <sys/usb/usba.h>

int usb_get_dev_data(dev_info_t *dip, usb_client_dev_data_t **dev_data,
usb_reg_parse_lvl_t parse_level, usb_flags_t flags);

void usb_free_dev_data(dev_info_t *dip, usb_client_dev_data_t *dev_data);

void usb_free_descr_tree(dev_info_t *dip, usb_client_dev_data_t *dev_data);

int usb_print_descr_tree(dev_info_t *dip, usb_client_dev_data_t *dev_data);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

For usb_get_dev_data():

dip
Pointer to device's dev_info structure.

dev_data
Address in which pointer to info is returned.

parse_level
Portion of device represented in the tree of parsed
descriptors. See below for possible
usb_reg_parse_lvl_t values and explanations.

flags
Not used.

For usb_free_dev_data():

dip
Pointer to device's dev_info structure.

dev_data
Pointer to usb_client_dev_data_t to be freed.

For usb_free_descr_tree():

dip
Pointer to device's dev_info structure.

dev_data
Pointer to usb_client_dev_data_t containing the
descriptor tree to free.

For usb_print_descr_tree():

dip
Pointer to device's dev_info structure.

dev_data
Pointer to usb_client_dev_data_t containing the
descriptor tree to display on-screen.

DESCRIPTION

The usb_get_dev_data() function interrogates a device and returns its
configuration information in a usb_client_dev_data_t structure. Most
USBA functions require information which comes from a
usb_client_dev_data_t, and all other functions in this man page
operate on this structure. Please see usb_client_dev_data(9S) for a
full content description. Pass the usb_client_dev_data_t structure to
usb_client_detach(9F) to completely deallocate it.

A descriptor tree is included in the information returned. The
usb_reg_parse_lvl_t type represents the extent of the device to be
represented by the returned tree (2nd arg to usb_get_dev_data) or
what is actually represented in the returned tree (dev_parse_level
field of the returned usb_client_dev_data_t). It has the following
possible values:

USB_PARSE_LVL_NONE
Build no tree. dev_n_cfg returns 0, dev_cfg
and dev_curr_cfg are returned NULL, and the
dev_curr_xxx fields are invalid.

USB_PARSE_LVL_IF
If configuration number and interface
properties are set (as when different
interfaces are viewed by the OS as different
device instances), parse configured interface
only. If an OS device instance is set up to
represent an entire physical device,
USB_PARSE_LVL_IF works like USB_PARSE_LVL_ALL.

USB_PARSE_LVL_CFG
Parse entire configuration of configured
interface only. Behaves similarly to
USB_PARSE_LVL_IF, except that entire
configuration is returned.

USB_PARSE_LVL_ALL
Parse entire device (all configurations), even
when driver is bound to a single interface of a
single configuration.

The usb_free_dev_data() function undoes what usb_get_dev_data() set
up. It releases memory for all strings, descriptors, and trees set
up by usb_get_dev_data().

The usb_free_descr_tree() function frees the descriptor tree of its
usb_client_dev_data_t argument, while leaving the rest of the
information intact. The intent is for drivers to free memory after
copying needed descriptor information from the tree. Upon return, the
following usb_client_dev_data_t fields are modified as follows:
dev_cfg is NULL, dev_n_cfg is zero and dev_parse_level is
USB_PARSE_LVL_NONE. Additionally, dev_curr_cfg is NULL and
dev_curr_if is invalid.

The usb_print_descr_tree() function is an easy-to-use diagnostic aid
which dumps the descriptor tree to the screen when the system is
verbose booted (boot -v). Output is spaced with blank lines for
readability and provides you with an on-screen look at what a device
has to offer.

RETURN VALUES

For usb_get_dev_data():

USB_SUCCESS
Registration is successful.

USB_INVALID_ARGS
dip or dev_data is NULL. parse_level is
invalid.

USB_INVALID_CONTEXT
Called from interrupt context.

USB_INVALID_VERSION
usb_client_attach(9F) was not called first.

USB_FAILURE
Bad descriptor info or other internal error.

For usb_free_dev_data(): None

For usb_free_descr_tree(): None, but no operation occurs if dip
and/or dev_data are NULL.

For usb_print_descr_tree():

USB_SUCCESS
Descriptor tree dump is successful.

USB_INVALID_ARGS
dev_data or dip are NULL.

USB_INVALID_CONTEXT
Called from interrupt context.

USB_FAILURE
Other error.

CONTEXT

The usb_get_dev_data() and usb_print_descr_tree() functions may be
called from user or kernel context.

The usb_free_dev_data() and usb_free_descr_tree() functions may be
called from user, kernel or interrupt context.

EXAMPLES

In this example, assume a device has the configuration shown
below, and the endpoint of config 2, iface 1, alt 1
which supports intr IN transfers needs to be found.
Config 2, iface 1 is the "default" config/iface for the
current OS device node.

config 1
iface 0
endpt 0
config 2
iface 0
iface 1
alt 0
endpt 0
cv 0
alt 1
endpt 0
endpt 1
cv 0
endpt 2
alt 2
endpt 0
cv 0

usb_client_dev_data_t *dev_data;
usb_ep_descr_t ep_descr;
usb_ep_data_t *ep_tree_node;
uint8_t interface = 1;
uint8_t alternate = 1;
uint8_t first_ep_number = 0;

/*
* We want default config/iface, so specify USB__PARSE_LVL_IF.
* Default config will be returned as dev_cfg[0].
/
if (usb_get_dev_data(dip, &dev_data,
USB_PARSE_LVL_IF, 0) != USB_SUCCESS) {
cmn_err (CE_WARN,
"%s%d: Couldn't get USB configuration descr tree",
ddi_driver_name(dip), ddi_get_instance(dip));

return (USB_FAILURE);
}

ep_tree_node = usb_lookup_ep_data(dip, dev_data, interface,
alternate, first_ep_number, USB_EP_ATTR_INTR, USB_EP_DIR_IN);
if (ep_tree_node != NULL) {
ep_descr = ep_tree_node->ep_descr;
} else {
cmn_r (CE_WARN,
"%s%d: Device is missing intr-IN endpoint",
ddi_driver_name(dip), ddi_get_instance(dip));

usb_free_descr_tree(dip, &dev_data);

return (USB_FAILURE);
}

ATTRIBUTES