Tribblix: manual page: usb_pipe

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

NAME

usb_pipe_reset - Abort queued requests from a USB pipe and reset the
pipe

SYNOPSIS

#include <sys/usb/usba.h>

void usb_pipe_reset(dev_info_t *dip,
usb_pipe_handle_t pipe_handle, usb_flags_t usb_flags,
void (*callback)(usb_pipe_handle_t cb_pipe_handle,
usb_opaque_t arg, int rval, usb_cb_flags_t flags),
usb_opaque_t callback_arg);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

dip
Pointer to the device's dev_info structure.

pipe_handle
Handle of the pipe to reset. Cannot be the handle to
the default control pipe.

usb_flags
USB_FLAGS_SLEEP is the only flag recognized. Wait for
completion.

callback
Function called on completion if the USB_FLAGS_SLEEP
flag is not specified. If NULL, no notification of
completion is provided.

callback_arg
Second argument to callback function.

DESCRIPTION

Call usb_pipe_reset() to reset a pipe which is in an error state, or
to abort a current request and clear the pipe. The usb_pipe_reset()
function can be called on any pipe other than the default control
pipe.

A pipe can be reset automatically when requests sent to the pipe have
the USB_ATTRS_AUTOCLEARING attribute specified. Client drivers see an
exception callback with the USB_CB_STALL_CLEARED callback flag set in
such cases.

Stalls on pipes executing requests without the USB_ATTRS_AUTOCLEARING
attribute set must be cleared by the client driver. The client driver
is notified of the stall via an exception callback. The client driver
must then call usb_pipe_reset() to clear the stall.

The usb_pipe_reset() function resets a pipe as follows:
1. Any polling activity is stopped if the pipe being reset is an
interrupt or isochronous pipe.
2. All pending requests are removed from the pipe. An exception
callback, if specified beforehand, is executed for each aborted
request.
3. The pipe is reset to the idle state.

Requests to reset the default control pipe are not allowed. No action
is taken on a pipe which is closing.

If USB_FLAGS_SLEEP is specified in flags, this function waits for the
action to complete before calling the callback handler and returning.
If not specified, this function queues the request and returns
immediately, and the specified callback is called upon completion.

callback is the callback handler. It takes the following arguments:

usb_pipe_handle_t cb_pipe_handle

Handle of the pipe to reset.

usb_opaque_t callback_arg

Callback_arg specified to usb_pipe_reset().

int rval

Return value of the reset call.

usb_cb_flags_t callback_flags

Status of the queueing operation. Can be:

USB_CB_NO_INFO -- Callback was uneventful.

USB_CB_ASYNC_REQ_FAILED -- Error starting asynchronous request.

RETURN VALUES

Status is returned to the caller via the callback handler's rval
argument. Possible callback handler rval argument values are:

USB_SUCCESS
Pipe successfully reset.

USB_INVALID_PIPE
pipe_handle specifies a pipe which is closed
or closing.

USB_INVALID_ARGS
dip or pipe_handle arguments are NULL.
USB_FLAGS_SLEEP is clear and callback is NULL.

USB_INVALID_CONTEXT
Called from interrupt context with the
USB_FLAGS_SLEEP flag set.

USB_INVALID_PERM
pipe_handle specifies the default control
pipe.

USB_FAILURE
Asynchronous resources are unavailable. In
this case, USB_CB_ASYNC_REQ_FAILED is passed
in as the callback_flags arg to the callback
handler.

Exception callback handlers of interrupt-IN and isochronous-IN
requests which are terminated by these commands are called with a
completion reason of USB_CR_STOPPED_POLLING.

Exception handlers of incomplete bulk requests are called with a
completion reason of USB_CR_FLUSHED.

Exception handlers of unstarted requests are called with
USB_CR_PIPE_RESET.

Note that messages mirroring the above errors are logged to the
console logfile on error. This provides status for calls which could
not otherwise provide status.

CONTEXT

May be called from user or kernel context regardless of arguments.
May be called from any callback with the USB_FLAGS_SLEEP clear. May
not be called from a callback executing in interrupt context if the
USB_FLAGS_SLEEP flag is set.

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

void post_reset_handler(
usb_pipe_handle_t, usb_opaque_t, int, usb_cb_flags_t);

/*
* Do an asynchronous reset on bulk_pipe.
* Execute post_reset_handler when done.
*/
usb_pipe_reset(dip, bulk_pipe, 0, post_reset_handler, arg);

/* Do a synchronous reset on bulk_pipe. */
usb_pipe_reset(dip, bulk_pipe, USB_FLAGS_SLEEP, NULL, NULL);

ATTRIBUTES