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

NAME

usb_get_cfg, usb_set_cfg - Get and set current USB device configuration

SYNOPSIS

#include <sys/usb/usba.h>


int usb_get_cfg(dev_info_t *dip, uint_t cfgval, usb_flags_t flags);


int usb_set_cfg(dev_info_t *dip, uint_t cfg_index, usb_flags_t flags,
void (*callback)(usb_pipe_handle_t pipe_handle, usb_opaque_t
callback_arg, int rval, usb_cb_flags_t flags), usb_opaque_t
callback_arg);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

For usb_get_cfg():

dip
Pointer to device's dev_info structure.


cfgval
Pointer to returned configuration value.


flags
Not used. Always waits for completion.


For usb_set_cfg():

dip
Pointer to device's dev_info structure.


cfg_index
Desired device configuration index. Set to
USB_DEV_DEFAULT_CONFIG_INDEX to restore default
configuration.


flags
Only USB_FLAGS_SLEEP is recognized. Wait for completion
and do not call callback.


callback
Callback handler to notify of asynchronous completion.


callback_arg
Second argument passed to callback handler.

DESCRIPTION

The usb_get_cfg() function retrieves the current configuration. It
ignores the flags argument and always blocks while contacting the device.


The usb_set_cfg() function sets a new configuration. Because this call
changes the device's mode of operation, the device must be quiescent and
have all pipes, with the exception of the default control pipe, closed.
The driver must have control over the entire device and cannot own just a
single interface on a composite device. Additionally, its device node
must not be a parent to other device nodes that can be operated by other
drivers. The driver must own the device exclusively, otherwise drivers
managing other parts of the device would be affected without their
knowledge or control.


This call updates all internal USBA framework data structures, whereas
issuing a raw USB_REQ_SET_CFG device request does not. The usb_set_cfg()
function is the only supported programmatic way to change device
configuration.


This call blocks if USB_FLAGS_SLEEP is set in flags. It returns
immediately and calls the callback on completion if USB_FLAGS_SLEEP is
not set.

RETURN VALUES

For usb_get_cfg():

USB_SUCCESS
New configuration is retrieved.


USB_INVALID_ARGS
cfgval or dip is NULL.


USB_FAILURE
Configuration cannot be retrieved.


For usb_set_cfg():

USB_SUCCESS
New configuration is set.


USB_INVALID_ARGS
dip is NULL.

USB_FLAGS_SLEEP is clear and callback is NULL.


USB_INVALID_CONTEXT
Called from interrupt context with USB_FLAGS_SLEEP
specified.


USB_INVALID_PERM
Caller does not own entire device or device is a
parent to child devices.


USB_BUSY
One or more pipes other than the default control
pipe are open on the device.


USB_INVALID_PIPE
Pipe handle is NULL or invalid, or pipe is closing
or closed.


USB_FAILURE
An illegal configuration is specified.

One or more pipes other than the default control
pipe are open on the device.

CONTEXT

The usb_get_cfg() function may be called from user or kernel context.


The usb_set_cfg() function may be called from user or kernel context
always. It may be called from interrupt context only if USB_FLAGS_SLEEP
is not set in flags.


If the USB_CB_ASYNC_REQ_FAILED bit is clear in usb_cb_flags_t, the
callback, if supplied, can block because it is executing in kernel
context. Otherwise the callback cannot block. Please see
usb_callback_flags(9S) for more information on callbacks.

EXAMPLES

Setting the configuration to the one at index 1 (in the
array of usb_cfg_data_t configuration nodes as returned
by usb_get_dev_data()), and verifying what the configuration
is at that index. (See usb_get_dev_data(9F)).

uint_t cfg_index = 1;

/*
* Assume all pipes other than the default control pipe
* are closed and make sure all requests to the default
* control pipe have completed. /
*/


if (usb_set_cfg(dip, cfg_index, USB_FLAGS_SLEEP, NULL, 0)
!= USB_SUCCESS) {
cmn_err (CE_WARN,
"%s%d: Error setting USB device to configuration #%d",
ddi_driver_name(dip), ddi_get_instance(dip), cfg_index);
}

if (usb_get_cfg(dip, &bConfigurationValue, 0) == USB_SUCCESS) {
cmn_err (CE_WARN, "%s%d: USB device active configuration is %d",
ddi_driver_name(dip), ddi_get_instance(dip),
bConfigurationValue);
} else {
...
...
}

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Architecture | PCI-based systems |
+--------------------+-------------------+
|Interface stability | Committed |
+--------------------+-------------------+

SEE ALSO

attributes(7), usb_get_alt_if(9F), usb_get_dev_data(9F),
usb_get_string_descr(9F), usb_pipe_xopen(9F), usb_callback_flags(9S),
usb_cfg_descr(9S), usb_ep_descr(9S), usb_if_descr(9S)


September 16, 2016 USB_GET_CFG(9F)