USB_ALLOC_REQUEST(9F) Kernel Functions for Drivers USB_ALLOC_REQUEST(9F)
NAME
usb_alloc_request, usb_alloc_ctrl_req, usb_free_ctrl_req,
usb_alloc_bulk_req, usb_free_bulk_req, usb_alloc_intr_req,
usb_free_intr_req, usb_alloc_isoc_req, usb_free_isoc_req - Allocate
and free USB transfer requests
SYNOPSIS
#include <sys/usb/usba.h>
usb_ctrl_req_t *usb_alloc_ctrl_req(
dev_info_t *dip,
size_t len,
usb_flags_t flags);
void usb_free_ctrl_req(
usb_ctrl_req_t *request);
usb_bulk_req_t *usb_alloc_bulk_req(
dev_info_t dip,
size_t len,
usb_flags_t flags);
void usb_free_bulk_req(
usb_bulk_req_t *request);
usb_intr_req_t *usb_alloc_intr_req(
dev_info_t *dip,
size_t len,
usb_flags_t flags);
void usb_free_intr_req(
usb_intr_req_t *request);
usb_isoc_req_t *usb_alloc_isoc_req(
dev_info_t *dip,
uint_t isoc_pkts_count,
size_t len,
usb_flags_t flags);
void usb_free_isoc_req(
usb_isoc_req_t *request);
INTERFACE LEVEL
illumos DDI specific (illumos DDI)
PARAMETERS
For
usb_alloc_ctrl_req(),
usb_alloc_bulk_req() and
usb_alloc_intr_req():
dip Pointer to the device's dev_info structure.
len Length of
data for this request.
flags Only USB_FLAGS_SLEEP is recognized. Wait for resources if
not immediately available.
For
usb_alloc_isoc_req():
dip Pointer to the device's dev_info structure.
isoc_pkts_count Number of isochronous packet descriptors to
associate with this request. Must be greater than
zero.
len Length of
data for this isochronous request.
flags Only USB_FLAGS_SLEEP is recognized. Wait for
resources if not immediately available.
For
usb_free_ctrl_req(),
usb_free_bulk_req(),
usb_free_intr_req() and
usb_free_isoc_req():
request Pointer to the request structure to be freed. Can be
NULL.
DESCRIPTION
The
usb_alloc_ctrl_req(),
usb_alloc_bulk_req(),
usb_alloc_intr_req(),
and
usb_alloc_isoc_req() functions allocate control, bulk, interrupt,
or isochronous requests. Optionally, these functions can also
allocate an mblk of the specified length to pass data associated
with the request. (For guidelines on mblk data allocation, see the
manpage for the relevant transfer function).
The
usb_alloc_isoc_req() function also allocates a number of
isochronous packet descriptors (usb_isoc_pkt_descr_t) specified by
isoc_pkts_count to the end of the request proper (usb_isoc_req_t).
See
usb_isoc_request(9S) for more information on isochronous packet
descriptors.
These functions always succeed when the USB_FLAGS_SLEEP flag is set,
provided that they are given valid args and are not called from
interrupt context.
The
usb_free_ctrl_req(),
usb_free_bulk_req(),
usb_free_intr_req(),
and
usb_free_isoc_req() functions free their corresponding request.
If the request's data block pointer is non-zero, the data block is
also freed. For isoc requests, the array of packet descriptors is
freed.
RETURN VALUES
For
usb_alloc_ctrl_req(),
usb_alloc_bulk_req(),
usb_alloc_intr_req() and
usb_alloc_isoc_req():
On success: returns a pointer to the appropriate usb_xxx_request_t.
On failure: returns
NULL. Fails because the dip argument is invalid,
USB_FLAGS_SLEEP is not set and memory is not available or because
USB_FLAGS_SLEEP is set but the call was made in interrupt context.
For
usb_free_ctrl_req(),
usb_free_bulk_req(),
usb_free_intr_req() and
usb_free_isoc_req(): None.
CONTEXT
The allocation routines can always be called from kernel and user
context. They may be called from interrupt context only if
USB_FLAGS_SLEEP is not specified.
The free routines may be called from kernel, user, and interrupt
context.
EXAMPLES
/* This allocates and initializes an asynchronous control
* request which will pass no data. Asynchronous requests
* are used when they cannot block the calling thread.
*/
usb_ctrl_req_t *ctrl_req;
if ((ctrl_req = usb_alloc_ctrl_req(dip, 0, 0)) == NULL) {
return (FAILURE);
}
/* Now initialize. */
ctrl_req->ctrl_bmRequestType = USB_DEV_REQ_DEV_TO_HOST |
USB_DEV_REQ_STANDARD | USB_DEV_REQ_RCPT_DEV;
ctrl_req->ctrl_bRequest = (uint8_t)USB_REQ_GET_STATUS;
...
...
ctrl_req->ctrl_callback = normal_callback;
ctrl_req->ctrl_exc_callback = exception_callback;
...
...
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Architecture | PCI-based systems |
+--------------------+-------------------+
|Interface stability | Committed |
+--------------------+-------------------+
SEE ALSO
attributes(7),
usb_get_current_frame_number(9F),
usb_get_max_pkts_per_isoc_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_bulk_request(9S),
usb_ctrl_request(9S),
usb_intr_request(9S),
usb_isoc_request(9S) July 25, 2004 USB_ALLOC_REQUEST(9F)
