/**
* usb_submit_urb - issue an asynchronous transfer request for an endpoint
* @urb: pointer to the urb describing the request
* @mem_flags: the type of memory to allocate, see kmalloc() for a list
* of valid options for this.
*
* This submits a transfer request, and transfers control of the URB
* describing that request to the USB subsystem. Request completion will
* be indicated later, asynchronously, by calling the completion handler.
* The three types of completion are success, error, and unlink
* (a software-induced fault, also called "request cancellation").
*
* URBs may be submitted in interrupt context.
*
* The caller must have correctly initialized the URB before submitting
* it. Functions such as usb_fill_bulk_urb() and usb_fill_control_urb() are
* available to ensure that most fields are correctly initialized, for
* the particular kind of transfer, although they will not initialize
* any transfer flags.
*
* Successful submissions return 0; otherwise this routine returns a
* negative error number. If the submission is successful, the complete()
* callback from the URB will be called exactly once, when the USB core and
* Host Controller Driver (HCD) are finished with the URB. When the completion
* function is called, control of the URB is returned to the device
* driver which issued the request. The completion handler may then
* immediately free or reuse that URB.
*
* With few exceptions, USB device drivers should never access URB fields
* provided by usbcore or the HCD until its complete() is called.
* The exceptions relate to periodic transfer scheduling. For both
* interrupt and isochronous urbs, as part of successful URB submission
* urb->interval is modified to reflect the actual transfer period used
* (normally some power of two units). And for isochronous urbs,
* urb->start_frame is modified to reflect when the URB's transfers were
* scheduled to start. Not all isochronous transfer scheduling policies
* will work, but most host controller drivers should easily handle ISO
* queues going from now until 10-200 msec into the future.
*
* For control endpoints, the synchronous usb_control_msg() call is
* often used (in non-interrupt context) instead of this call.
* That is often used through convenience wrappers, for the requests
* that are standardized in the USB 2.0 specification. For bulk
* endpoints, a synchronous usb_bulk_msg() call is available.
*
* Request Queuing:
*
* URBs may be submitted to endpoints before previous ones complete, to
* minimize the impact of interrupt latencies and system overhead on data
* throughput. With that queuing policy, an endpoint's queue would never
* be empty. This is required for continuous isochronous data streams,
* and may also be required for some kinds of interrupt transfers. Such
* queuing also maximizes bandwidth utilization by letting USB controllers
* start work on later requests before driver software has finished the
* completion processing for earlier (successful) requests.
*
* As of Linux 2.6, all USB endpoint transfer queues support depths greater
* than one. This was previously a HCD-specific behavior, except for ISO
* transfers. Non-isochronous endpoint queues are inactive during cleanup
* after faults (transfer errors or cancellation).
*
* Reserved Bandwidth Transfers:
*
* Periodic transfers (interrupt or isochronous) are performed repeatedly,
* using the interval specified in the urb. Submitting the first urb to
* the endpoint reserves the bandwidth necessary to make those transfers.
* If the USB subsystem can't allocate sufficient bandwidth to perform
* the periodic request, submitting such a periodic request should fail.
*
* For devices under xHCI, the bandwidth is reserved at configuration time, or
* when the alt setting is selected. If there is not enough bus bandwidth, the
* configuration/alt setting request will fail. Therefore, submissions to
* periodic endpoints on devices under xHCI should never fail due to bandwidth
* constraints.
*
* Device drivers must explicitly request that repetition, by ensuring that
* some URB is always on the endpoint's queue (except possibly for short
* periods during completion callacks). When there is no longer an urb
* queued, the endpoint's bandwidth reservation is canceled. This means
* drivers can use their completion handlers to ensure they keep bandwidth
* they need, by reinitializing and resubmitting the just-completed urb
* until the driver longer needs that periodic bandwidth.
*
* Memory Flags:
*
* The general rules for how to decide which mem_flags to use
* are the same as for kmalloc. There are four
* different possible values; GFP_KERNEL, GFP_NOFS, GFP_NOIO and
* GFP_ATOMIC.
*
* GFP_NOFS is not ever used, as it has not been implemented yet.
*
* GFP_ATOMIC is used when
* (a) you are inside a completion handler, an interrupt, bottom half,
* tasklet or timer, or
* (b) you are holding a spinlock or rwlock (does not apply to
* semaphores), or
* (c) current->state != TASK_RUNNING, this is the case only after
* you've changed it.
*
* GFP_NOIO is used in the block io path and error handling of storage
* devices.
*
* All other situations use GFP_KERNEL.
*
* Some more specific rules for mem_flags can be inferred, such as
* (1) start_xmit, timeout, and receive methods of network drivers must
* use GFP_ATOMIC (they are called with a spinlock held);
* (2) queuecommand methods of scsi drivers must use GFP_ATOMIC (also
* called with a spinlock held);
* (3) If you use a kernel thread with a network driver you must use
* GFP_NOIO, unless (b) or (c) apply;
* (4) after you have done a down() you can use GFP_KERNEL, unless (b) or (c)
* apply or your are in a storage driver's block io path;
* (5) USB probe and disconnect can use GFP_KERNEL unless (b) or (c) apply; and
* (6) changing firmware on a running storage or net device uses
* GFP_NOIO, unless b) or c) apply
*
*/
int usb_submit_urb(struct urb *urb, gfp_t mem_flags)
{
int xfertype, max;
struct usb_device *dev;
struct usb_host_endpoint *ep;
int is_out;
if (!urb || urb->hcpriv || !urb->complete)
return -EINVAL;
dev = urb->dev;
if ((!dev) || (dev->state < USB_STATE_UNAUTHENTICATED))
return -ENODEV;
/* For now, get the endpoint from the pipe. Eventually drivers
* will be required to set urb->ep directly and we will eliminate
* urb->pipe.
*/
ep = usb_pipe_endpoint(dev, urb->pipe);
if (!ep)
return -ENOENT;
urb->ep = ep;
urb->status = -EINPROGRESS;
urb->actual_length = 0;
/* Lots of sanity checks, so HCDs can rely on clean data
* and don't need to duplicate tests
*/
xfertype = usb_endpoint_type(&ep->desc);
if (xfertype == USB_ENDPOINT_XFER_CONTROL) {
struct usb_ctrlrequest *setup =
(struct usb_ctrlrequest *) urb->setup_packet;
if (!setup)
return -ENOEXEC;
is_out = !(setup->bRequestType & USB_DIR_IN) ||
!setup->wLength;
} else {
is_out = usb_endpoint_dir_out(&ep->desc);
}
/* Clear the internal flags and cache the direction for later use */
urb->transfer_flags &= ~(URB_DIR_MASK | URB_DMA_MAP_SINGLE |
URB_DMA_MAP_PAGE | URB_DMA_MAP_SG | URB_MAP_LOCAL |
URB_SETUP_MAP_SINGLE | URB_SETUP_MAP_LOCAL |
URB_DMA_SG_COMBINED);
urb->transfer_flags |= (is_out ? URB_DIR_OUT : URB_DIR_IN);
if (xfertype != USB_ENDPOINT_XFER_CONTROL &&
dev->state < USB_STATE_CONFIGURED)
return -ENODEV;
max = usb_endpoint_maxp(&ep->desc);
if (max <= 0) {
dev_dbg(&dev->dev,
"bogus endpoint ep%d%s in %s (bad maxpacket %d)\n",
usb_endpoint_num(&ep->desc), is_out ? "out" : "in",
__func__, max);
return -EMSGSIZE;
}
/* periodic transfers limit size per frame/uframe,
* but drivers only control those sizes for ISO.
* while we're checking, initialize return status.
*/
if (xfertype == USB_ENDPOINT_XFER_ISOC) {
int n, len;
/* SuperSpeed isoc endpoints have up to 16 bursts of up to
* 3 packets each
*/
if (dev->speed == USB_SPEED_SUPER) {
int burst = 1 + ep->ss_ep_comp.bMaxBurst;
int mult = USB_SS_MULT(ep->ss_ep_comp.bmAttributes);
max *= burst;
max *= mult;
}
/* "high bandwidth" mode, 1-3 packets/uframe? */
if (dev->speed == USB_SPEED_HIGH) {
int mult = 1 + ((max >> 11) & 0x03);
max &= 0x07ff;
max *= mult;
}
static int single_step_get_dev_desc(struct usb_hcd *hcd, u8 port)
{
struct xhci_hcd *xhci = hcd_to_xhci(hcd);
struct urb *urb;
struct usb_device *hdev;
struct usb_device *udev = NULL;
struct usb_ctrlrequest setup_packet;
char data_buffer[USB_DT_DEVICE_SIZE];
int ret = 0;
xhci_info(xhci, "Testing SINGLE_STEP_GET_DEV_DESC\n");
hdev = hcd->self.root_hub;
if (!hdev) {
xhci_err(xhci, "EHSET: root_hub pointer is NULL\n");
ret = -EPIPE;
goto error;
}
if (hdev->children[port] != NULL)
udev = hdev->children[port];
if (!udev) {
xhci_err(xhci, "EHSET: device available is NOT found\n");
ret = -EPIPE;
goto error;
}
urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urb) {
xhci_err(xhci, "urb : get alloc failed\n");
ret = -ENOMEM;
goto error;
}
setup_packet.bRequestType = USB_DIR_IN |
USB_TYPE_STANDARD | USB_RECIP_DEVICE;
setup_packet.bRequest = USB_REQ_GET_DESCRIPTOR;
setup_packet.wValue = (USB_DT_DEVICE << 8);
setup_packet.wIndex = 0;
setup_packet.wLength = USB_DT_DEVICE_SIZE;
urb->dev = udev;
urb->hcpriv = udev->ep0.hcpriv;
urb->setup_packet = (unsigned char *)&setup_packet;
urb->transfer_buffer = data_buffer;
urb->transfer_buffer_length = USB_DT_DEVICE_SIZE;
urb->actual_length = 0;
urb->transfer_flags = URB_DIR_IN | URB_HCD_DRIVER_TEST;
urb->pipe = usb_rcvctrlpipe(udev, 0);
urb->ep = usb_pipe_endpoint(udev, urb->pipe);
if (!urb->ep) {
xhci_err(xhci, "urb->ep is NULL\n");
ret = -ENOENT;
goto error_urb_ep;
}
urb->setup_dma = dma_map_single(
hcd->self.controller,
urb->setup_packet,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
if (dma_mapping_error(hcd->self.controller, urb->setup_dma)) {
xhci_err(xhci, "setup : dma_map_single failed\n");
ret = -EBUSY;
goto error_setup_dma;
}
urb->transfer_dma = dma_map_single(
hcd->self.controller,
urb->transfer_buffer,
urb->transfer_buffer_length,
DMA_TO_DEVICE);
if (dma_mapping_error(hcd->self.controller, urb->transfer_dma)) {
xhci_err(xhci, "xfer : dma_map_single failed\n");
ret = -EBUSY;
goto error_xfer_dma;
}
ret = xhci_urb_enqueue_single_step(hcd, urb, GFP_ATOMIC, 1);
dma_unmap_single(hcd->self.controller, urb->transfer_dma,
sizeof(struct usb_ctrlrequest), DMA_TO_DEVICE);
error_xfer_dma:
dma_unmap_single(hcd->self.controller, urb->setup_dma,
sizeof(struct usb_ctrlrequest), DMA_TO_DEVICE);
error_setup_dma:
error_urb_ep:
usb_free_urb(urb);
error:
return ret;
}
