hcd.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 1,586 行 · 第 1/3 页

	struct usb_hcd		*hcd = urb->dev->bus->hcpriv;
	struct hcd_dev		*dev = urb->dev->hcpriv;
	unsigned long		flags;

	if (!hcd || !dev)
		return -ENODEV;

	/*
	 * FIXME:  make urb timeouts be generic, keeping the HCD cores
	 * as simple as possible.
	 */

	// NOTE:  a generic device/urb monitoring hook would go here.
	// hcd_monitor_hook(MONITOR_URB_SUBMIT, urb)
	// It would catch submission paths for all urbs.

	/*
	 * Atomically queue the urb,  first to our records, then to the HCD.
	 * Access to urb->status is controlled by urb->lock ... changes on
	 * i/o completion (normal or fault) or unlinking.
	 */

	// FIXME:  verify that quiescing hc works right (RH cleans up)

	spin_lock_irqsave (&hcd_data_lock, flags);
	if (unlikely (urb->reject))
		status = -EPERM;
	else if (HCD_IS_RUNNING (hcd->state) &&
			hcd->state != USB_STATE_QUIESCING) {
		usb_get_dev (urb->dev);
		list_add_tail (&urb->urb_list, &dev->urb_list);
		status = 0;
	} else
		status = -ESHUTDOWN;
	spin_unlock_irqrestore (&hcd_data_lock, flags);
	if (status) {
		INIT_LIST_HEAD (&urb->urb_list);
		return status;
	}

	/* increment urb's reference count as part of giving it to the HCD
	 * (which now controls it).  HCD guarantees that it either returns
	 * an error or calls giveback(), but not both.
	 */
	urb = usb_get_urb (urb);
	atomic_inc (&urb->use_count);

	if (urb->dev == hcd->self.root_hub) {
		/* NOTE:  requirement on hub callers (usbfs and the hub
		 * driver, for now) that URBs' urb->transfer_buffer be
		 * valid and usb_buffer_{sync,unmap}() not be needed, since
		 * they could clobber root hub response data.
		 */
		urb->transfer_flags |= (URB_NO_TRANSFER_DMA_MAP
					| URB_NO_SETUP_DMA_MAP);
		status = rh_urb_enqueue (hcd, urb);
		goto done;
	}

	/* lower level hcd code should use *_dma exclusively,
	 * unless it uses pio or talks to another transport.
	 */
	if (hcd->self.controller->dma_mask) {
		if (usb_pipecontrol (urb->pipe)
			&& !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
			urb->setup_dma = dma_map_single (
					hcd->self.controller,
					urb->setup_packet,
					sizeof (struct usb_ctrlrequest),
					DMA_TO_DEVICE);
		if (urb->transfer_buffer_length != 0
			&& !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
			urb->transfer_dma = dma_map_single (
					hcd->self.controller,
					urb->transfer_buffer,
					urb->transfer_buffer_length,
					usb_pipein (urb->pipe)
					    ? DMA_FROM_DEVICE
					    : DMA_TO_DEVICE);
	}

	status = hcd->driver->urb_enqueue (hcd, urb, mem_flags);
done:
	if (unlikely (status)) {
		urb_unlink (urb);
		atomic_dec (&urb->use_count);
		if (urb->reject)
			wake_up (&usb_kill_urb_queue);
		usb_put_urb (urb);
	}
	return status;
}

/*-------------------------------------------------------------------------*/

/* called in any context */
static int hcd_get_frame_number (struct usb_device *udev)
{
	struct usb_hcd	*hcd = (struct usb_hcd *)udev->bus->hcpriv;
	if (!HCD_IS_RUNNING (hcd->state))
		return -ESHUTDOWN;
	return hcd->driver->get_frame_number (hcd);
}

/*-------------------------------------------------------------------------*/

/* this makes the hcd giveback() the urb more quickly, by kicking it
 * off hardware queues (which may take a while) and returning it as
 * soon as practical.  we've already set up the urb's return status,
 * but we can't know if the callback completed already.
 */
static int
unlink1 (struct usb_hcd *hcd, struct urb *urb)
{
	int		value;

	if (urb == (struct urb *) hcd->rh_timer.data)
		value = usb_rh_status_dequeue (hcd, urb);
	else {

		/* The only reason an HCD might fail this call is if
		 * it has not yet fully queued the urb to begin with.
		 * Such failures should be harmless. */
		value = hcd->driver->urb_dequeue (hcd, urb);
	}

	if (value != 0)
		dev_dbg (hcd->self.controller, "dequeue %p --> %d\n",
				urb, value);
	return value;
}

/*
 * called in any context
 *
 * caller guarantees urb won't be recycled till both unlink()
 * and the urb's completion function return
 */
static int hcd_unlink_urb (struct urb *urb, int status)
{
	struct hcd_dev			*dev;
	struct usb_hcd			*hcd = NULL;
	struct device			*sys = NULL;
	unsigned long			flags;
	struct list_head		*tmp;
	int				retval;

	if (!urb)
		return -EINVAL;

	/*
	 * we contend for urb->status with the hcd core,
	 * which changes it while returning the urb.
	 *
	 * Caller guaranteed that the urb pointer hasn't been freed, and
	 * that it was submitted.  But as a rule it can't know whether or
	 * not it's already been unlinked ... so we respect the reversed
	 * lock sequence needed for the usb_hcd_giveback_urb() code paths
	 * (urb lock, then hcd_data_lock) in case some other CPU is now
	 * unlinking it.
	 */
	spin_lock_irqsave (&urb->lock, flags);
	spin_lock (&hcd_data_lock);

	if (!urb->dev || !urb->dev->bus) {
		retval = -ENODEV;
		goto done;
	}

	dev = urb->dev->hcpriv;
	sys = &urb->dev->dev;
	hcd = urb->dev->bus->hcpriv;
	if (!dev || !hcd) {
		retval = -ENODEV;
		goto done;
	}

	/* running ~= hc unlink handshake works (irq, timer, etc)
	 * halted ~= no unlink handshake is needed
	 * suspended, resuming == should never happen
	 */
	WARN_ON (!HCD_IS_RUNNING (hcd->state) && hcd->state != USB_STATE_HALT);

	/* insist the urb is still queued */
	list_for_each(tmp, &dev->urb_list) {
		if (tmp == &urb->urb_list)
			break;
	}
	if (tmp != &urb->urb_list) {
		retval = -EIDRM;
		goto done;
	}

	/* Any status except -EINPROGRESS means something already started to
	 * unlink this URB from the hardware.  So there's no more work to do.
	 */
	if (urb->status != -EINPROGRESS) {
		retval = -EBUSY;
		goto done;
	}

	/* PCI IRQ setup can easily be broken so that USB controllers
	 * never get completion IRQs ... maybe even the ones we need to
	 * finish unlinking the initial failed usb_set_address().
	 */
	if (!hcd->saw_irq) {
		dev_warn (hcd->self.controller, "Unlink after no-IRQ?  "
			"Different ACPI or APIC settings may help."
			"\n");
		hcd->saw_irq = 1;
	}

	urb->status = status;

	spin_unlock (&hcd_data_lock);
	spin_unlock_irqrestore (&urb->lock, flags);

	retval = unlink1 (hcd, urb);
	if (retval == 0)
		retval = -EINPROGRESS;
	return retval;

done:
	spin_unlock (&hcd_data_lock);
	spin_unlock_irqrestore (&urb->lock, flags);
	if (retval != -EIDRM && sys && sys->driver)
		dev_dbg (sys, "hcd_unlink_urb %p fail %d\n", urb, retval);
	return retval;
}

/*-------------------------------------------------------------------------*/

/* disables the endpoint: cancels any pending urbs, then synchronizes with
 * the hcd to make sure all endpoint state is gone from hardware. use for
 * set_configuration, set_interface, driver removal, physical disconnect.
 *
 * example:  a qh stored in hcd_dev.ep[], holding state related to endpoint
 * type, maxpacket size, toggle, halt status, and scheduling.
 */
static void hcd_endpoint_disable (struct usb_device *udev, int endpoint)
{
	struct hcd_dev	*dev;
	struct usb_hcd	*hcd;
	struct urb	*urb;
	unsigned	epnum = endpoint & USB_ENDPOINT_NUMBER_MASK;

	dev = udev->hcpriv;
	hcd = udev->bus->hcpriv;

	WARN_ON (!HCD_IS_RUNNING (hcd->state) && hcd->state != USB_STATE_HALT);

	local_irq_disable ();

rescan:
	/* (re)block new requests, as best we can */
	if (endpoint & USB_DIR_IN) {
		usb_endpoint_halt (udev, epnum, 0);
		udev->epmaxpacketin [epnum] = 0;
	} else {
		usb_endpoint_halt (udev, epnum, 1);
		udev->epmaxpacketout [epnum] = 0;
	}

	/* then kill any current requests */
	spin_lock (&hcd_data_lock);
	list_for_each_entry (urb, &dev->urb_list, urb_list) {
		int	tmp = urb->pipe;

		/* ignore urbs for other endpoints */
		if (usb_pipeendpoint (tmp) != epnum)
			continue;
		/* NOTE assumption that only ep0 is a control endpoint */
		if (epnum != 0 && ((tmp ^ endpoint) & USB_DIR_IN))
			continue;

		/* another cpu may be in hcd, spinning on hcd_data_lock
		 * to giveback() this urb.  the races here should be
		 * small, but a full fix needs a new "can't submit"
		 * urb state.
		 */
		if (urb->status != -EINPROGRESS)
			continue;
		usb_get_urb (urb);
		spin_unlock (&hcd_data_lock);

		spin_lock (&urb->lock);
		tmp = urb->status;
		if (tmp == -EINPROGRESS)
			urb->status = -ESHUTDOWN;
		spin_unlock (&urb->lock);

		/* kick hcd unless it's already returning this */
		if (tmp == -EINPROGRESS) {
			tmp = urb->pipe;
			unlink1 (hcd, urb);
			dev_dbg (hcd->self.controller,
				"shutdown urb %p pipe %08x ep%d%s%s\n",
				urb, tmp, usb_pipeendpoint (tmp),
				(tmp & USB_DIR_IN) ? "in" : "out",
				({ char *s; \
				 switch (usb_pipetype (tmp)) { \
				 case PIPE_CONTROL:	s = ""; break; \
				 case PIPE_BULK:	s = "-bulk"; break; \
				 case PIPE_INTERRUPT:	s = "-intr"; break; \
				 default: 		s = "-iso"; break; \
				}; s;}));
		}
		usb_put_urb (urb);

		/* list contents may have changed */
		goto rescan;
	}
	spin_unlock (&hcd_data_lock);
	local_irq_enable ();

	/* synchronize with the hardware, so old configuration state
	 * clears out immediately (and will be freed).
	 */
	might_sleep ();
	if (hcd->driver->endpoint_disable)
		hcd->driver->endpoint_disable (hcd, dev, endpoint);
}

/*-------------------------------------------------------------------------*/

#ifdef	CONFIG_USB_SUSPEND

static int hcd_hub_suspend (struct usb_bus *bus)
{
	struct usb_hcd		*hcd;

	hcd = container_of (bus, struct usb_hcd, self);
	if (hcd->driver->hub_suspend)
		return hcd->driver->hub_suspend (hcd);
	return 0;
}

static int hcd_hub_resume (struct usb_bus *bus)
{
	struct usb_hcd		*hcd;

	hcd = container_of (bus, struct usb_hcd, self);
	if (hcd->driver->hub_resume)
		return hcd->driver->hub_resume (hcd);
	return 0;
}

#endif

/*-------------------------------------------------------------------------*/

/* called by khubd, rmmod, apmd, or other thread for hcd-private cleanup.
 * we're guaranteed that the device is fully quiesced.  also, that each
 * endpoint has been hcd_endpoint_disabled.
 */

static int hcd_free_dev (struct usb_device *udev)
{
	struct hcd_dev		*dev;
	struct usb_hcd		*hcd;
	unsigned long		flags;

	if (!udev || !udev->hcpriv)
		return -EINVAL;

	if (!udev->bus || !udev->bus->hcpriv)
		return -ENODEV;

	// should udev->devnum == -1 ??

	dev = udev->hcpriv;
	hcd = udev->bus->hcpriv;

	/* device driver problem with refcounts? */
	if (!list_empty (&dev->urb_list)) {
		dev_dbg (hcd->self.controller, "free busy dev, %s devnum %d (bug!)\n",
			hcd->self.bus_name, udev->devnum);
		return -EINVAL;
	}

	spin_lock_irqsave (&hcd_data_lock, flags);
	list_del (&dev->dev_list);
	udev->hcpriv = NULL;
	spin_unlock_irqrestore (&hcd_data_lock, flags);

	kfree (dev);
	return 0;
}

/*
 * usb_hcd_operations - adapts usb_bus framework to HCD framework (bus glue)
 *
 * When registering a USB bus through the HCD framework code, use this
 * usb_operations vector.  The PCI glue layer does so automatically; only
 * bus glue for non-PCI system busses will need to use this.
 */
struct usb_operations usb_hcd_operations = {
	.allocate =		hcd_alloc_dev,
	.get_frame_number =	hcd_get_frame_number,
	.submit_urb =		hcd_submit_urb,
	.unlink_urb =		hcd_unlink_urb,
	.deallocate =		hcd_free_dev,
	.buffer_alloc =		hcd_buffer_alloc,
	.buffer_free =		hcd_buffer_free,
	.disable =		hcd_endpoint_disable,
#ifdef	CONFIG_USB_SUSPEND
	.hub_suspend =		hcd_hub_suspend,
	.hub_resume =		hcd_hub_resume,
#endif
};
EXPORT_SYMBOL (usb_hcd_operations);

/*-------------------------------------------------------------------------*/

/**
 * usb_hcd_giveback_urb - return URB from HCD to device driver
 * @hcd: host controller returning the URB
 * @urb: urb being returned to the USB device driver.
 * @regs: pt_regs, passed down to the URB completion handler
 * Context: in_interrupt()
 *
 * This hands the URB from HCD to its USB device driver, using its
 * completion function.  The HCD has freed all per-urb resources
 * (and is done using urb->hcpriv).  It also released all HCD locks;
 * the device driver won't cause problems if it frees, modifies,
 * or resubmits this URB.
 */
void usb_hcd_giveback_urb (struct usb_hcd *hcd, struct urb *urb, struct pt_regs *regs)
{
	urb_unlink (urb);

	// NOTE:  a generic device/urb monitoring hook would go here.
	// hcd_monitor_hook(MONITOR_URB_FINISH, urb, dev)
	// It would catch exit/unlink paths for all urbs.

	/* lower level hcd code should use *_dma exclusively */
	if (hcd->self.controller->dma_mask) {
		if (usb_pipecontrol (urb->pipe)
			&& !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP))
			dma_unmap_single (hcd->self.controller, urb->setup_dma,
					sizeof (struct usb_ctrlrequest),
					DMA_TO_DEVICE);
		if (urb->transfer_buffer_length != 0
			&& !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
			dma_unmap_single (hcd->self.controller, 
					urb->transfer_dma,
					urb->transfer_buffer_length,
					usb_pipein (urb->pipe)
					    ? DMA_FROM_DEVICE
					    : DMA_TO_DEVICE);
	}

	/* pass ownership to the completion handler */
	urb->complete (urb, regs);
	atomic_dec (&urb->use_count);
	if (unlikely (urb->reject))
		wake_up (&usb_kill_urb_queue);
	usb_put_urb (urb);
}
EXPORT_SYMBOL (usb_hcd_giveback_urb);

/*-------------------------------------------------------------------------*/

/**
 * usb_hcd_irq - hook IRQs to HCD framework (bus glue)
 * @irq: the IRQ being raised
 * @__hcd: pointer to the HCD whose IRQ is beinng signaled
 * @r: saved hardware registers
 *
 * When registering a USB bus through the HCD framework code, use this
 * to handle interrupts.  The PCI glue layer does so automatically; only
 * bus glue for non-PCI system busses will need to use this.
 */
irqreturn_t usb_hcd_irq (int irq, void *__hcd, struct pt_regs * r)
{
	struct usb_hcd		*hcd = __hcd;
	int			start = hcd->state;

	if (unlikely (hcd->state == USB_STATE_HALT))	/* irq sharing? */
		return IRQ_NONE;

	hcd->saw_irq = 1;
	if (hcd->driver->irq (hcd, r) == IRQ_NONE)
		return IRQ_NONE;

	if (hcd->state != start && hcd->state == USB_STATE_HALT)
		usb_hc_died (hcd);
	return IRQ_HANDLED;
}
EXPORT_SYMBOL (usb_hcd_irq);

/*-------------------------------------------------------------------------*/

static void hcd_panic (void *_hcd)
{
	struct usb_hcd		*hcd = _hcd;
	struct usb_device	*hub = hcd->self.root_hub;
	unsigned		i;

	/* hc's root hub is removed later removed in hcd->stop() */
	down (&hub->serialize);
	usb_set_device_state(hub, USB_STATE_NOTATTACHED);
	for (i = 0; i < hub->maxchild; i++) {
		if (hub->children [i])
			usb_disconnect (&hub->children [i]);
	}
	up (&hub->serialize);
}

/**
 * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
 * @hcd: pointer to the HCD representing the controller
 *
 * This is called by bus glue to report a USB host controller that died
 * while operations may still have been pending.  It's called automatically
 * by the PCI glue, so only glue for non-PCI busses should need to call it. 
 */
void usb_hc_died (struct usb_hcd *hcd)
{
	dev_err (hcd->self.controller, "HC died; cleaning up\n");

	/* clean up old urbs and devices; needs a task context */
	INIT_WORK (&hcd->work, hcd_panic, hcd);
	(void) schedule_work (&hcd->work);
}
EXPORT_SYMBOL (usb_hc_died);