USBA_HCDI_DUP_ISOC_REQ(9F) Kernel Functions for Drivers

NAME


usba_hcdi_dup_isoc_req - duplicate an isochronous request

SYNOPSIS


#include <sys/usb/usba/hcdi.h>

usb_isoc_req_t *
usba_hcdi_dup_isoc_req(dev_info_t *dip, usb_isoc_req_t *usrp,
usb_flags_t flags);

INTERFACE LEVEL


Volatile - illumos USB HCD private function

This is a private function that is not part of the stable DDI. It may be
removed or changed at any time.

PARAMETERS


dip A pointer to the HCD driver's dev_info structure.

usrp A pointer to the USB isochronous request which will be
duplicated.

flags

USB_FLAGS_NOSLEEP
Do not block waiting for memory. If memory is not
available the allocation will fail.

USB_FLAGS_SLEEP
Perform a blocking allocation. If memory is not
available, the function will wait until memory is
made available.

Note, the request may still fail even if
USB_FLAGS_SLEEP is specified.

DESCRIPTION


The usba_hcdi_dup_isoc_req() function is used to duplicate an existing
isochronous request, usrp.

When the USBA framework initiates an isochronous in transfer with the
usba_hcdi_pipe_isoc_xfer(9E) entry point, it is the HCD driver's
responsibility to receive the periodic data from the pipe. When there is
data available, the HCD must duplicate the original isochronous request and
copy the available data into the request structure's isoc_data member,
before handing over the request structure to the USBA framework by calling
the usba_hcdi_cb(9F) function.

In addition to duplicating the request, it is the callers responsibility to
increase the pipe handle's request count. For more information, see
usba_hcdi_pipe_isoc_xfer(9E).

The dip argument should correspond to the HCD driver's dev_info_t
structure. The usrp pointer should correspond to the initial isochronous
request. The flags member must be appropriate for the context. If
USB_FLAGS_SLEEP is passed while in interrupt context, then this function
may fail.

CONTEXT


The usba_hcdi_dup_isoc_req() function may be called from user, kernel, or
interrupt context; however, when in interrupt context, the value of flags
must be USB_FLAGS_NOSLEEP.

RETURN VALUES


Upon successful completion, the usba_hcdi_dup_isoc_req() function returns a
pointer to a duplicate isochronous request. Otherwise, NULL is returned to
indicate that the request could not be duplicated.

SEE ALSO


usba_hcdi(9E), usba_hcdi_pipe_isoc_xfer(9E), usba_hcdi_cb(9F)

illumos September 16, 2016 illumos