hcd.c

linux core 函数例程

		dev->bus->bandwidth_isoc_reqs--;
	else
		dev->bus->bandwidth_int_reqs--;

#ifdef USB_BANDWIDTH_MESSAGES
	dbg ("bandwidth alloc reduced by %d (%s) to %d for %d requesters",
		urb->bandwidth,
		isoc ? "ISOC" : "INTR",
		dev->bus->bandwidth_allocated,
		dev->bus->bandwidth_int_reqs + dev->bus->bandwidth_isoc_reqs);
#endif
	urb->bandwidth = 0;
}
EXPORT_SYMBOL (usb_release_bandwidth);


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

#ifdef CONFIG_PCI

/* PCI-based HCs are normal, but custom bus glue should be ok */

static void hcd_irq (int irq, void *__hcd, struct pt_regs *r);
static void hc_died (struct usb_hcd *hcd);

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

/* configure so an HC device and id are always provided */
/* always called with process context; sleeping is OK */

/**
 * usb_hcd_pci_probe - initialize PCI-based HCDs
 * @dev: USB Host Controller being probed
 * @id: pci hotplug id connecting controller to HCD framework
 * Context: !in_interrupt()
 *
 * Allocates basic PCI resources for this USB host controller, and
 * then invokes the start() method for the HCD associated with it
 * through the hotplug entry's driver_data.
 *
 * Store this function in the HCD's struct pci_driver as probe().
 */
int usb_hcd_pci_probe (struct pci_dev *dev, const struct pci_device_id *id)
{
	struct hc_driver	*driver;
	unsigned long		resource, len;
	void			*base;
	u8			latency, limit;
	struct usb_hcd		*hcd;
	int			retval, region;
	char			buf [8], *bufp = buf;

	if (!id || !(driver = (struct hc_driver *) id->driver_data))
		return -EINVAL;

	if (pci_enable_device (dev) < 0)
		return -ENODEV;
	
        if (!dev->irq) {
        	err ("Found HC with no IRQ.  Check BIOS/PCI %s setup!",
			dev->slot_name);
   	        return -ENODEV;
        }
	
	if (driver->flags & HCD_MEMORY) {	// EHCI, OHCI
		region = 0;
		resource = pci_resource_start (dev, 0);
		len = pci_resource_len (dev, 0);
		if (!request_mem_region (resource, len, driver->description)) {
			dbg ("controller already in use");
			return -EBUSY;
		}
		base = ioremap_nocache (resource, len);
		if (base == NULL) {
			dbg ("error mapping memory");
			retval = -EFAULT;
clean_1:
			release_mem_region (resource, len);
			err ("init %s fail, %d", dev->slot_name, retval);
			return retval;
		}

	} else { 				// UHCI
		resource = len = 0;
		for (region = 0; region < PCI_ROM_RESOURCE; region++) {
			if (!(pci_resource_flags (dev, region) & IORESOURCE_IO))
				continue;

			resource = pci_resource_start (dev, region);
			len = pci_resource_len (dev, region);
			if (request_region (resource, len,
					driver->description))
				break;
		}
		if (region == PCI_ROM_RESOURCE) {
			dbg ("no i/o regions available");
			return -EBUSY;
		}
		base = (void *) resource;
	}

	// driver->start(), later on, will transfer device from
	// control by SMM/BIOS to control by Linux (if needed)

	pci_set_master (dev);
	hcd = driver->hcd_alloc ();
	if (hcd == NULL){
		dbg ("hcd alloc fail");
		retval = -ENOMEM;
clean_2:
		if (driver->flags & HCD_MEMORY) {
			iounmap (base);
			goto clean_1;
		} else {
			release_region (resource, len);
			err ("init %s fail, %d", dev->slot_name, retval);
			return retval;
		}
	}
	pci_set_drvdata(dev, hcd);
	hcd->driver = driver;
	hcd->description = driver->description;
	hcd->pdev = dev;
	info ("%s @ %s, %s", hcd->description,  dev->slot_name, dev->name);

	pci_read_config_byte (dev, PCI_LATENCY_TIMER, &latency);
	if (latency) {
		pci_read_config_byte (dev, PCI_MAX_LAT, &limit);
		if (limit && limit < latency) {
			dbg ("PCI latency reduced to max %d", limit);
			pci_write_config_byte (dev, PCI_LATENCY_TIMER, limit);
		}
	}

#ifndef __sparc__
	sprintf (buf, "%d", dev->irq);
#else
	bufp = __irq_itoa(dev->irq);
#endif
	if (request_irq (dev->irq, hcd_irq, SA_SHIRQ, hcd->description, hcd)
			!= 0) {
		err ("request interrupt %s failed", bufp);
		retval = -EBUSY;
		driver->hcd_free (hcd);
		goto clean_2;
	}
	hcd->irq = dev->irq;

	hcd->regs = base;
	hcd->region = region;
	info ("irq %s, %s %p", bufp,
		(driver->flags & HCD_MEMORY) ? "pci mem" : "io base",
		base);

	usb_init_bus (&hcd->self);
	hcd->self.op = &hcd_operations;
	hcd->self.hcpriv = (void *) hcd;
	hcd->self.bus_name = dev->slot_name;
	hcd->product_desc = dev->name;

	INIT_LIST_HEAD (&hcd->dev_list);

	usb_register_bus (&hcd->self);

	if ((retval = driver->start (hcd)) < 0)
		usb_hcd_pci_remove (dev);

	return retval;
} 
EXPORT_SYMBOL (usb_hcd_pci_probe);


/* may be called without controller electrically present */
/* may be called with controller, bus, and devices active */

/**
 * usb_hcd_pci_remove - shutdown processing for PCI-based HCDs
 * @dev: USB Host Controller being removed
 * Context: !in_interrupt()
 *
 * Reverses the effect of usb_hcd_pci_probe(), first invoking
 * the HCD's stop() method.  It is always called from a thread
 * context, normally "rmmod", "apmd", or something similar.
 *
 * Store this function in the HCD's struct pci_driver as remove().
 */
void usb_hcd_pci_remove (struct pci_dev *dev)
{
	struct usb_hcd		*hcd;
	struct usb_device	*hub;

	hcd = pci_get_drvdata(dev);
	if (!hcd)
		return;
	info ("remove: %s, state %x", hcd->self.bus_name, hcd->state);

	if (in_interrupt ()) BUG ();

	hub = hcd->self.root_hub;
	hcd->state = USB_STATE_QUIESCING;

	dbg ("%s: roothub graceful disconnect", hcd->self.bus_name);
	usb_disconnect (&hub);

	hcd->driver->stop (hcd);
	hcd->state = USB_STATE_HALT;

	free_irq (hcd->irq, hcd);
	if (hcd->driver->flags & HCD_MEMORY) {
		iounmap (hcd->regs);
		release_mem_region (pci_resource_start (dev, 0),
			pci_resource_len (dev, 0));
	} else {
		release_region (pci_resource_start (dev, hcd->region),
			pci_resource_len (dev, hcd->region));
	}

	usb_deregister_bus (&hcd->self);
	if (atomic_read (&hcd->self.refcnt) != 1)
		err ("usb_hcd_pci_remove %s, count != 1", hcd->self.bus_name);

	hcd->driver->hcd_free (hcd);
}
EXPORT_SYMBOL (usb_hcd_pci_remove);


#ifdef	CONFIG_PM

/*
 * Some "sleep" power levels imply updating struct usb_driver
 * to include a callback asking hcds to do their bit by checking
 * if all the drivers can suspend.  Gets involved with remote wakeup.
 *
 * If there are pending urbs, then HCs will need to access memory,
 * causing extra power drain.  New sleep()/wakeup() PM calls might
 * be needed, beyond PCI suspend()/resume().  The root hub timer
 * still be accessing memory though ...
 *
 * FIXME:  USB should have some power budgeting support working with
 * all kinds of hubs.
 *
 * FIXME:  This assumes only D0->D3 suspend and D3->D0 resume.
 * D1 and D2 states should do something, yes?
 *
 * FIXME:  Should provide generic enable_wake(), calling pci_enable_wake()
 * for all supported states, so that USB remote wakeup can work for any
 * devices that support it (and are connected via powered hubs).
 *
 * FIXME:  resume doesn't seem to work right any more...
 */


// 2.4 kernels have issued concurrent resumes (w/APM)
// we defend against that error; PCI doesn't yet.

/**
 * usb_hcd_pci_suspend - power management suspend of a PCI-based HCD
 * @dev: USB Host Controller being suspended
 *
 * Store this function in the HCD's struct pci_driver as suspend().
 */
int usb_hcd_pci_suspend (struct pci_dev *dev, u32 state)
{
	struct usb_hcd		*hcd;
	int			retval;

	hcd = pci_get_drvdata(dev);
	info ("suspend %s to state %d", hcd->self.bus_name, state);

	pci_save_state (dev, hcd->pci_state);

	// FIXME for all connected devices, leaf-to-root:
	// driver->suspend()
	// proposed "new 2.5 driver model" will automate that

	/* driver may want to disable DMA etc */
	retval = hcd->driver->suspend (hcd, state);
	hcd->state = USB_STATE_SUSPENDED;

 	pci_set_power_state (dev, state);
	return retval;
}
EXPORT_SYMBOL (usb_hcd_pci_suspend);

/**
 * usb_hcd_pci_resume - power management resume of a PCI-based HCD
 * @dev: USB Host Controller being resumed
 *
 * Store this function in the HCD's struct pci_driver as resume().
 */
int usb_hcd_pci_resume (struct pci_dev *dev)
{
	struct usb_hcd		*hcd;
	int			retval;

	hcd = pci_get_drvdata(dev);
	info ("resume %s", hcd->self.bus_name);

	/* guard against multiple resumes (APM bug?) */
	atomic_inc (&hcd->resume_count);
	if (atomic_read (&hcd->resume_count) != 1) {
		err ("concurrent PCI resumes for %s", hcd->self.bus_name);
		retval = 0;
		goto done;
	}

	retval = -EBUSY;
	if (hcd->state != USB_STATE_SUSPENDED) {
		dbg ("can't resume, not suspended!");
		goto done;
	}
	hcd->state = USB_STATE_RESUMING;

	pci_set_power_state (dev, 0);
	pci_restore_state (dev, hcd->pci_state);

	retval = hcd->driver->resume (hcd);
	if (!HCD_IS_RUNNING (hcd->state)) {
		dbg ("resume %s failure, retval %d", hcd->self.bus_name, retval);
		hc_died (hcd);
// FIXME:  recover, reset etc.
	} else {
		// FIXME for all connected devices, root-to-leaf:
		// driver->resume ();
		// proposed "new 2.5 driver model" will automate that
	}

done:
	atomic_dec (&hcd->resume_count);
	return retval;
}
EXPORT_SYMBOL (usb_hcd_pci_resume);

#endif	/* CONFIG_PM */

#endif

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

/*
 * Generic HC operations.
 */

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

/* called from khubd, or root hub init threads for hcd-private init */
static int hcd_alloc_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;
	hcd = udev->bus->hcpriv;
	if (hcd->state == USB_STATE_QUIESCING)
		return -ENOLINK;

	dev = (struct hcd_dev *) kmalloc (sizeof *dev, GFP_KERNEL);
	if (dev == NULL)
		return -ENOMEM;
	memset (dev, 0, sizeof *dev);

	INIT_LIST_HEAD (&dev->dev_list);
	INIT_LIST_HEAD (&dev->urb_list);

	spin_lock_irqsave (&hcd_data_lock, flags);
	list_add (&dev->dev_list, &hcd->dev_list);
	// refcount is implicit
	udev->hcpriv = dev;
	spin_unlock_irqrestore (&hcd_data_lock, flags);

	return 0;
}

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

static void hc_died (struct usb_hcd *hcd)
{
	struct list_head	*devlist, *urblist;
	struct hcd_dev		*dev;
	struct urb		*urb;
	unsigned long		flags;
	
	/* flag every pending urb as done */
	spin_lock_irqsave (&hcd_data_lock, flags);
	list_for_each (devlist, &hcd->dev_list) {
		dev = list_entry (devlist, struct hcd_dev, dev_list);
		list_for_each (urblist, &dev->urb_list) {
			urb = list_entry (urblist, struct urb, urb_list);
			dbg ("shutdown %s urb %p pipe %x, current status %d",
				hcd->self.bus_name, urb, urb->pipe, urb->status);
			if (urb->status == -EINPROGRESS)
				urb->status = -ESHUTDOWN;
		}
	}
	urb = (struct urb *) hcd->rh_timer.data;
	if (urb)
		urb->status = -ESHUTDOWN;
	spin_unlock_irqrestore (&hcd_data_lock, flags);

	if (urb)
		rh_status_dequeue (hcd, urb);
	hcd->driver->stop (hcd);
}

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

static void urb_unlink (struct urb *urb)
{
	unsigned long		flags;
	struct usb_device	*dev;

	/* Release any periodic transfer bandwidth */
	if (urb->bandwidth)
		usb_release_bandwidth (urb->dev, urb,
			usb_pipeisoc (urb->pipe));

	/* clear all state linking urb to this dev (and hcd) */

	spin_lock_irqsave (&hcd_data_lock, flags);
	list_del_init (&urb->urb_list);
	dev = urb->dev;
	urb->dev = NULL;
	usb_put_dev (dev);
	spin_unlock_irqrestore (&hcd_data_lock, flags);
}


/* may be called in any context with a valid urb->dev usecount */
/* caller surrenders "ownership" of urb */

static int hcd_submit_urb (struct urb *urb, int mem_flags)
{
	int			status;
	struct usb_hcd		*hcd;
	struct hcd_dev		*dev;
	unsigned long		flags;
	int			pipe, temp, max;

	if (!urb || urb->hcpriv || !urb->complete)
		return -EINVAL;

	urb->status = -EINPROGRESS;
	urb->actual_length = 0;
	urb->bandwidth = 0;
	INIT_LIST_HEAD (&urb->urb_list);

	if (!urb->dev || !urb->dev->bus || urb->dev->devnum <= 0)
		return -ENODEV;
	hcd = urb->dev->bus->hcpriv;
	dev = urb->dev->hcpriv;