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
Solaris DDI specific (Solaris 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 imme‐
diately 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 imme‐
diately 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 allo‐
cate 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 inter‐
rupt 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 con‐
text. 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 con‐
text.
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(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │PCI-based systems │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWusb │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOattributes(5), usb_get_current_frame_number(9F),
usb_get_max_pkts_per_isoc_request(9F), usb_pipe_get_max_bulk_trans‐
fer_size(9F), usb_pipe_bulk_xfer(9F), usb_pipe_ctrl_xfer(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)SunOS 5.10 25 July 2004 usb_alloc_request(9F)
