Tribblix: manual page: usba_hcdi_pipe_bulk

USBA_HCDI_PIPE_BULK_XFER(9E) Driver Entry Points

NAME

usba_hcdi_pipe_bulk_xfer - perform a USB bulk transfer

SYNOPSIS

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

int
prefix_hcdi_pipe_bulk_xfer(usba_pipe_handle_data_t *ph,
usb_bulk_req_t *ubrp, usb_flags_t usb_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

ph A pointer to a USB pipe handle as defined in
usba_pipe_handle_data(9S).

ubrp A pointer to a USB bulk transfer request. The
structure's members are documented in usb_bulk_req(9S).

usb_flags Flags which describe how allocations should be performed.
Valid flags are:

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_pipe_bulk_xfer() entry point is used to initiate an
asynchronous USB bulk transfer on the pipe ph. The specific USB bulk
transfer is provided in ubrp. For more background on transfer types,
see usba_hcdi(9E).

The host controller driver should first check the USB address of the
pipe handle. It may correspond to the root hub. If it does, the
driver should return USB_NOT_SUPPORTED.

Bulk transfers may send data to the device or receive data from the
device. A given bulk endpoint is uni-directional. The direction can
be determined from the endpoint address based on the p_ep member of
ubrp. See usb_ep_descr(9S) for more information on how to determine
the direction of the endpoint.

The device driver should allocate memory, whether memory suitable for a
DMA transfer or otherwise, to perform the transfer. For all memory
allocated, it should honor the values in usb_flags to determine whether
or not it should block for allocations.

The length of the bulk transfer and its data can be found in the
bulk_len and bulk_data members of ubrp respectively. The mblk(9S)
structure that should not be used directly and data should be copied to
or from the data buffer that will go the controller.

If the driver successfully schedules the I/O, then it should return
USB_SUCCESS. When the I/O completes, it must call usba_hcdi_cb(9F)
with ubrp. If the transfer fails, but the driver returned USB_SUCCESS,
it still must call usba_hcdi_cb(9F) and should specify an error there.

It is the driver's responsibility to time out bulk transfer requests.
If the timeout in the request as indicated in the bulk_timeout member
of ubrp is set to zero, then the driver should use the USBA default
timeout of HCDI_DEFAULT_TIMEOUT. All timeout values are in seconds.

Callback Handling

When the bulk transfer completes the driver should consider the
following items to determine what actions it should take on the
callback:

+o If the transfer timed out, it should remove the transfer from the
outstanding list, queue the next transfer, and return the transfer
back to the OS with the error code USB_CR_TIMEOUT with
usba_hcdi_cb(9F).

+o If the transfer failed, it should find the appropriate error and
call usba_hcdi_cb(9F) with that error.

+o If the transfer succeeded, but less data was transferred than
expected, consult the bulk_attributes member of the ubrp. If the
USB_ATTRS_SHORT_XFER_OK flag is not present, then the driver should
call usba_hcdi_cb(9F) with the error USB_CR_DATA_UNDERRUN.

+o If the transfer was going to the host, then the driver should copy
the data into the transfer's message block and update the b_wptr
member of the mblk(9S).

+o If everything was successful, call usba_hcdi_cb(9F) with the code
USB_CR_OK.

RETURN VALUES

Upon successful completion, the usba_hcdi_pipe_bulk_xfer() function
should return USB_SUCCESS. Otherwise, it should return the appropriate
USB error. If uncertain, use USB_FAILURE.