Tribblix: manual page: usb_pipe_intr

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

NAME

usb_pipe_intr_xfer, usb_pipe_stop_intr_polling - USB interrupt
transfer and polling functions

SYNOPSIS

#include <sys/usb/usba.h>

int usb_pipe_intr_xfer(usb_pipe_handle_t pipe_handle, usb_intr_req_t *request,
usb_flags_t flags);

void usb_pipe_stop_intr_polling(usb_pipe_handle_t pipe_handle, usb__flags_t flags);

INTERFACE LEVEL

illumos DDI specific (illumos DDI)

PARAMETERS

For usb_pipe_intr_xfer():

pipe_handle
Interrupt pipe handle on which request is made.

request
Pointer to interrupt transfer request.

flags
USB_FLAGS_SLEEP is the only flag recognized. Wait for
needed resources if unavailable. For requests
specifying the USB_ATTRS_ONE_XFER attribute, wait for
the request to complete.

For usb_pipe_stop_intr_polling():

pipe_handle
Interrupt pipe handle on which to stop polling for
data.

flags
USB_FLAGS_SLEEP is the only flag recognized. Wait for
polling to stop.

DESCRIPTION

The usb_pipe_intr_xfer() function requests the USBA framework to
perform a transfer through a USB interrupt pipe. The request is
passed to the host controller driver (HCD), which performs the
necessary transactions to complete the request.

There are three categories of interrupt transfers: periodic or polled
interrupt-IN, single-transfer interrupt-IN, and (single-transfer)
interrupt-OUT.

Periodic Interrupt-IN Transfers
Periodic or polled interrupt-IN transfers execute on input requests
which do not have the USB_ATTRS_ONE_XFER attribute set. One request
enables repetitive transfers at a periodic rate set by the endpoint's
bInterval. There can be only one interrupt-IN request submitted at a
time.

Periodic interrupt-IN transfers are always asynchronous. Client
driver notification of new data is always via a callback. The
USB_FLAGS_SLEEP flag is only to wait for resources to become
available. Callbacks must always be in place to receive transfer
completion notification. Please see usb_callback_flags(9S) for
details on USB callbacks.

Calls made to usb_pipe_intr_xfer() for starting input polling need
allocate only one request. The USBA framework allocates a new request
each time polling has new data to return. (Note that each request
returned must be freed via usb_free_intr_req(9F). Specify a zero
length when calling usb_alloc_intr_req() to allocate the original
request, since it will not be used to return data. Set the intr_len
in the request to specify how much data can be returned per polling
interval.

The original request passed to usb_pipe_intr_xfer() is used to return
status when polling is terminated, or on an error condition when the
USB_ATTRS_AUTOCLEARING attribute is set for the request. If
autoclearing is not set, the current (non-original) request is
returned on error. Call usb_pipe_reset(9F) to reset the pipe and get
back the original request in this case. The USB_CR_STOPPED_POLLING
flag is always set for callbacks where the original request is
returned.

Single-transfer Interrupt-IN Transfers
Interrupt-IN requests which have the USB_ATTRS_ONE_XFER attribute
perform a single transfer. Such requests are synchronous when the
USB_FLAGS_SLEEP flag is specified. Calls for synchronous requests do
not return until their transaction is complete, and their callbacks
are optional. The request is returned to the client through the
normal or the exception completion callback to signal either normal
completion or an error condition.

Interrupt-OUT Transfers
Interrupt-OUT requests always set up for a single transfer. However,
multiple requests can be queued and execute in periodic fashion until
depleted.

Interrupt-OUT transfers are synchronous when the USB_FLAGS_SLEEP flag
is set in the request's flags. Calls for synchronous transfers will
not return until their transaction has completed. Calls for
asynchronous transfers notify the client driver of transaction
completion via a normal callback, or error completion via an
exception callback.

The usb_pipe_stop_intr_polling() function terminates polling on
interrupt-IN pipes and does the following:
1. Cease polling.
2. Allow any requests-in-progress to complete and be returned to
the client driver through the normal callback mechanism.
3. Idle the pipe.
4. Return the original polling request to the client driver through
an exception callback with a completion reason of
USB_CR_STOPPED_POLLING.

The client driver may restart polling from an exception callback only
if the callback corresponds to an original request. The callback
handler checks for the following completion reasons to ensure that a
callback corresponds to an original request:

USB_CR_STOPPED_POLLING,
USB_CR_PIPE_RESET,
USB_CR_PIPE_CLOSING,
USB_CR_NOT_SUPPORTED

The callback handler also checks the request's intr_data field to
mark original polling requests, when the requests are created with a
zero len argument. In this case, a NULL intr_data field
distinguishes a returned original request from a request allocated by
the framework during polling.

Mblks for data for interrupt-OUT requests are allocated when a
request is allocated via usb_alloc_intr_req(9F) by passing a non-
negative value for the len argument.

RETURN VALUES

For usb_pipe_intr_xfer()

USB_SUCCESS
Transfer was successful.

USB_INVALID_ARGS
Request is NULL.

USB_INVALID_CONTEXT
Called from interrupt context with the
USB_FLAGS_SLEEP flag set.

USB_INVALID_REQUEST
The request has been freed or otherwise
invalidated.

A set of conflicting attributes was
specified. See usb_intr_request(9S).

The normal and/or exception callback was
NULL, USB_FLAGS_SLEEP was not set and
USB_ATTRS_ONE_XFER was not set.

An interrupt request was specified with a
NULL data and a non-zero intr_len value.

An IN interrupt request was specified with
both polling (USB_ATTRS_ONE_XFER clear in
attributes) and non-zero timeout specified.

An IN interrupt request was specified with a
non-NULL data argument.

An OUT interrupt request was specified with
a NULL data argument.

USB_INVALID_PIPE
Pipe handle is NULL or invalid.

Pipe is closing or closed.

USB_PIPE_ERROR
Pipe handle refers to a pipe which is in the
USB_PIPE_STATE_ERROR state.

USB_NO_RESOURCES
Memory, descriptors or other resources
unavailable.

USB_HC_HARDWARE_ERROR
Host controller is in error state.

USB_FAILURE
An asynchronous transfer failed or an
internal error occurred.

An intr polling request is made while
polling is already in progress.

The pipe is in an unsuitable state (error,
busy, not ready).

Additional status information may be
available in the intr_completion_reason and
intr_cb_flags fields of the request. Please
see usb_completion_reason(9S) and
usb_callback_flags(9S) for more information.

For usb_pipe_stop_intr_polling()

None, but fails if called with USB_FLAGS_SLEEP specified from
interrupt context, pipe handle is invalid, NULL or pertains to a
closing or closed pipe, or the pipe is in an error state. Error
messages are logged to the console logfile.

Exception handlers' queued requests which are flushed by these
commands before execution are returned with completion reason of
USB_CR_FLUSHED.

CONTEXT

Both of these functions can be called from kernel or user context
without regard to arguments, and may be called from interrupt context
only when the USB_FLAGS_SLEEP flag is clear.

EXAMPLES

/* Start polling on interrupt-IN pipe. */

usb_intr_req_t intr_req;
void intr_pipe_callback(usb_pipe_handle_t, usb_intr_req_t*);
void intr_pipe_exception_callback(
usb_pipe_handle_t, usb_intr_req_t*);
usb_ep_descr_t *ep_descr;

ep_descr = ...;
intr_req = usb_alloc_intr_req(dip, 0, USB_FLAGS_SLEEP);
...
...
intr_req->intr_attributes = USB_ATTRS_SHORT_XFER_OK;
intr_req->intr_len = ep_descr->wMaxPacketSize;
...
...
intr_req->intr_cb = intr_pipe_callback;
intr_req->intr_exc_cb = intr_pipe_exception_callback;

if ((rval = usb_pipe_intr_xfer(pipe, intr_req, USB_FLAGS_NOSLEEP))
!= USB_SUCCESS) {
cmn_err (CE_WARN, "%s%d: Error starting interrupt pipe polling.",
ddi_driver_name(dip), ddi_get_instance(dip));
}

-------

/* Stop polling before setting device idle. Wait for polling to stop. */

usb_pipe_stop_intr_polling(pipe, USB_FLAGS_SLEEP);
(void) pm_idle_component(dip, 0);

-------

/* Allocate, initialize and issue a synchronous intr-OUT request. */

usb_intr_req_t intr_req;
mblk_t *mblk;
usb_ep_descr_t *ep_descr;

ep_descr = ...;

intr_req =
usb_alloc_intr_req(dip, ep_descr->wMaxPacketSize, USB_FLAGS_SLEEP);

intr_req->intr_attributes = USB_ATTRS_AUTOCLEARING;
mblk = intr_req->intr_data;
bcopy(buffer, mblk->b_wptr, ep_descr->wMaxPacketSize);
mblk->b_wptr += ep_descr->wMaxPacketSize;

if ((rval = usb_pipe_intr_xfer(pipe, intr_req, USB_FLAGS_SLEEP))
!= USB_SUCCESS) {
cmn_err (CE_WARN, "%s%d: Error writing intr data.",
ddi_driver_name(dip), ddi_get_instance(dip));
}

ATTRIBUTES