USB_BULK_REQUEST(9S) Data Structures for Drivers USB_BULK_REQUEST(9S)

NAME


usb_bulk_req, usb_bulk_req_t, usb_bulk_request - USB bulk request
structure

SYNOPSIS


#include <sys/usb/usba.h>


INTERFACE LEVEL


illumos DDI specific (illumos DDI)

DESCRIPTION


A bulk request (that is, a request sent through a bulk pipe) is used to
transfer large amounts of data in reliable but non-time-critical fashion.
Please refer to Section 5.8 of the USB 2.0 specification for information
on bulk transfers. (The USB 2.0 specification is available at
www.usb.org.)


The fields in the usb_bulk_req_t are used to format a bulk request.
Please see below for acceptable combinations of flags and attributes.


The usb_bulk_req_t fields are:

uint_t bulk_len; /* number of bytes to xfer */
/* Please see */
/* usb_pipe_get_max_bulk_transfer_size(9F) */
/* for maximum size */
mblk_t *bulk_data; /* the data for the data phase */
/* IN or OUT: allocated by client */
uint_t bulk_timeout; /* xfer timeout value in secs */
/* If set to zero, defaults to 5 sec */
usb_opaque_t bulk_client_private; /* Client specific information */
usb_req_attrs_t bulk_attributes; /* xfer-attributes */

/* Normal callback function, called upon completion. */
void (*bulk_cb)(
usb_pipe_handle_t ph, struct usb_bulk_req *req);

/* Exception callback function, for error handling. */
void (*bulk_exc_cb)(
usb_pipe_handle_t ph, struct usb_bulk_req *req);

/* set by USBA/HCD framework on completion */
usb_cr_t bulk_completion_reason; /* overall success status */
/* See usb_completion_reason(9S) */
usb_cb_flags_t bulk_cb_flags; /* recovery done by callback hndlr */
/* See usb_callback_flags(9S) */


Request attributes define special handling for transfers. The following
attributes are valid for bulk requests:

USB_ATTRS_SHORT_XFER_OK
USB framework accepts transfers where less
data is received than expected.


USB_ATTRS_AUTOCLEARING
USB framework resets pipe and clears
functional stalls automatically on exception.


USB_ATTRS_PIPE_RESET
USB framework resets pipe automatically on
exception.


Please see usb_request_attributes(9S) for more information.


Bulk transfers/requests are subject to the following constraints and
caveats:


1) The following table indicates combinations of usb_pipe_bulk_xfer()
flags argument and fields of the usb_bulk_req_t request argument (X =
don't care).


Flags Type Attributes Data Timeout Semantics
---------------------------------------------------------------
X X X ==NULL X illegal

X X ONE_XFER X X illegal

no sleep IN !SHORT_XFER_OK !=NULL 0 See note (A)

no sleep IN !SHORT_XFER_OK !=NULL > 0 See note (B)

sleep IN !SHORT_XFER_OK !=NULL 0 See note (C)

sleep IN !SHORT_XFER_OK !=NULL > 0 See note (D)

no sleep IN SHORT_XFER_OK !=NULL 0 See note (E)

no sleep IN SHORT_XFER_OK !=NULL > 0 See note (F)

sleep IN SHORT_XFER_OK !=NULL 0 See note (G)

sleep IN SHORT_XFER_OK !=NULL > 0 See note (H)

X OUT SHORT_XFER_OK X X illegal

no sleep OUT X !=NULL 0 See note (I)

no sleep OUT X !=NULL > 0 See note (J)

sleep OUT X !=NULL 0 See note (K)

sleep OUT X !=NULL > 0 See note (L)


Table notes:
A). Fill buffer, no timeout, callback when bulk_len is transferred.
B). Fill buffer, with timeout; callback when bulk_len is transferred.
C). Fill buffer, no timeout, unblock when bulk_len is transferred; no
callback.
D). Fill buffer, with timeout; unblock when bulk_len is transferred or
a timeout occurs; no callback.
E) Fill buffer, no timeout, callback when bulk_len is transferred or
first short packet is received.
F). Fill buffer, with timeout; callback when bulk_len is transferred or
first short packet is received.
G). Fill buffer, no timeout, unblock when bulk_len is transferred or
first short packet is received; no callback.
H). Fill buffer, with timeout; unblock when bulk_len is transferred,
first short packet is received, or a timeout occurs; no callback.
I). Empty buffer, no timeout; callback when bulk_len is transferred.
J) Empty buffer, with timeout; callback when bulk_len is transferred or
a timeout occurs.
K). Empty buffer, no timeout; unblock when bulk_len is transferred; no
callback.
L). Empty buffer, with timeout; unblock when bulk_len is transferred or
a timeout occurs; no callback.


2) bulk_len must be > 0. bulk_data must not be NULL.


3) Bulk_residue is set for both READ and WRITE. If it is set to 0, it
means that all of the data was transferred successfully. In case of
WRITE it contains data not written and in case of READ it contains the
data NOT read so far. A residue can only occur because of timeout or
bus/device error. (Note that a short transfer for a request where the
USB_ATTRS_SHORT_XFER_OK attribute is not set is considered a device
error.) An exception callback is made and completion_reason will be non-
zero.


4) Splitting large bulk transfers: Due to internal constraints, the USBA
framework can only do a limited size bulk data transfer per request. A
client driver may first determine this limitation by calling the USBA
interface, usb_pipe_get_max_bulk_transfer_size(9F), and then restrict
itself to doing transfers in multiples of this fixed size. This forces a
client driver to do data transfers in a loop for a large request,
splitting it into multiple chunks of fixed size.


The bulk_completion_reason indicates the status of the transfer. See
usb_completion_reason(9S) for usb_cr_t definitions.


The bulk_cb_flags are set prior to calling the exception callback handler
to summarize recovery actions taken and errors encountered during
recovery. See usb_callback_flags(9S) for usb_cb_flags_t definitions.


--- Callback handling ---


All usb request types share the same callback handling. See
usb_callback_flags(9S) for details.

ATTRIBUTES


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


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

SEE ALSO


usb_alloc_request(9F), usb_pipe_bulk_xfer(9F), usb_pipe_ctrl_xfer(9F),
usb_pipe_get_max_bulk_transfer_size(9F), usb_pipe_intr_xfer(9F),
usb_pipe_isoc_xfer(9F), usb_callback_flags(9S),
usb_completion_reason(9S), usb_ctrl_request(9S), usb_intr_request(9S),
usb_isoc_request(9S), usb_request_attributes(9S)

illumos January 5, 2004 USB_BULK_REQUEST(9S)