hub.c

底层驱动开发

	/* rebind drivers that had no suspend() */
	if (status == 0) {
		usb_lock_all_devices();
		bus_rescan_devices(&usb_bus_type);
		usb_unlock_all_devices();
	}
	return status;
}

static int remote_wakeup(struct usb_device *udev)
{
	int	status = 0;

	/* don't repeat RESUME sequence if this device
	 * was already woken up by some other task
	 */
	down(&udev->serialize);
	if (udev->state == USB_STATE_SUSPENDED) {
		dev_dbg(&udev->dev, "RESUME (wakeup)\n");
		/* TRSMRCY = 10 msec */
		msleep(10);
		status = finish_port_resume(udev);
	}
	up(&udev->serialize);
	return status;
}

static int hub_suspend(struct usb_interface *intf, pm_message_t state)
{
	struct usb_hub		*hub = usb_get_intfdata (intf);
	struct usb_device	*hdev = hub->hdev;
	unsigned		port1;
	int			status;

	/* stop khubd and related activity */
	hub_quiesce(hub);

	/* then suspend every port */
	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
		struct usb_device	*udev;

		udev = hdev->children [port1-1];
		if (!udev)
			continue;
		down(&udev->serialize);
		status = __usb_suspend_device(udev, port1, state);
		up(&udev->serialize);
		if (status < 0)
			dev_dbg(&intf->dev, "suspend port %d --> %d\n",
				port1, status);
	}

	intf->dev.power.power_state = state;
	return 0;
}

static int hub_resume(struct usb_interface *intf)
{
	struct usb_device	*hdev = interface_to_usbdev(intf);
	struct usb_hub		*hub = usb_get_intfdata (intf);
	unsigned		port1;
	int			status;

	if (intf->dev.power.power_state.event == PM_EVENT_ON)
		return 0;

	for (port1 = 1; port1 <= hdev->maxchild; port1++) {
		struct usb_device	*udev;
		u16			portstat, portchange;

		udev = hdev->children [port1-1];
		status = hub_port_status(hub, port1, &portstat, &portchange);
		if (status == 0) {
			if (portchange & USB_PORT_STAT_C_SUSPEND) {
				clear_port_feature(hdev, port1,
					USB_PORT_FEAT_C_SUSPEND);
				portchange &= ~USB_PORT_STAT_C_SUSPEND;
			}

			/* let khubd handle disconnects etc */
			if (portchange)
				continue;
		}

		if (!udev || status < 0)
			continue;
		down (&udev->serialize);
		if (portstat & USB_PORT_STAT_SUSPEND)
			status = hub_port_resume(hub, port1, udev);
		else {
			status = finish_port_resume(udev);
			if (status < 0) {
				dev_dbg(&intf->dev, "resume port %d --> %d\n",
					port1, status);
				hub_port_logical_disconnect(hub, port1);
			}
		}
		up(&udev->serialize);
	}
	intf->dev.power.power_state = PMSG_ON;

	hub->resume_root_hub = 0;
	hub_activate(hub);
	return 0;
}

void usb_resume_root_hub(struct usb_device *hdev)
{
	struct usb_hub *hub = hdev_to_hub(hdev);

	hub->resume_root_hub = 1;
	kick_khubd(hub);
}

#else	/* !CONFIG_USB_SUSPEND */

int usb_suspend_device(struct usb_device *udev, pm_message_t state)
{
	return 0;
}

int usb_resume_device(struct usb_device *udev)
{
	return 0;
}

#define	hub_suspend		NULL
#define	hub_resume		NULL
#define	remote_wakeup(x)	0

#endif	/* CONFIG_USB_SUSPEND */

EXPORT_SYMBOL(usb_suspend_device);
EXPORT_SYMBOL(usb_resume_device);



/* USB 2.0 spec, 7.1.7.3 / fig 7-29:
 *
 * Between connect detection and reset signaling there must be a delay
 * of 100ms at least for debounce and power-settling.  The corresponding
 * timer shall restart whenever the downstream port detects a disconnect.
 * 
 * Apparently there are some bluetooth and irda-dongles and a number of
 * low-speed devices for which this debounce period may last over a second.
 * Not covered by the spec - but easy to deal with.
 *
 * This implementation uses a 1500ms total debounce timeout; if the
 * connection isn't stable by then it returns -ETIMEDOUT.  It checks
 * every 25ms for transient disconnects.  When the port status has been
 * unchanged for 100ms it returns the port status.
 */

#define HUB_DEBOUNCE_TIMEOUT	1500
#define HUB_DEBOUNCE_STEP	  25
#define HUB_DEBOUNCE_STABLE	 100

static int hub_port_debounce(struct usb_hub *hub, int port1)
{
	int ret;
	int total_time, stable_time = 0;
	u16 portchange, portstatus;
	unsigned connection = 0xffff;

	for (total_time = 0; ; total_time += HUB_DEBOUNCE_STEP) {
		ret = hub_port_status(hub, port1, &portstatus, &portchange);
		if (ret < 0)
			return ret;

		if (!(portchange & USB_PORT_STAT_C_CONNECTION) &&
		     (portstatus & USB_PORT_STAT_CONNECTION) == connection) {
			stable_time += HUB_DEBOUNCE_STEP;
			if (stable_time >= HUB_DEBOUNCE_STABLE)
				break;
		} else {
			stable_time = 0;
			connection = portstatus & USB_PORT_STAT_CONNECTION;
		}

		if (portchange & USB_PORT_STAT_C_CONNECTION) {
			clear_port_feature(hub->hdev, port1,
					USB_PORT_FEAT_C_CONNECTION);
		}

		if (total_time >= HUB_DEBOUNCE_TIMEOUT)
			break;
		msleep(HUB_DEBOUNCE_STEP);
	}

	dev_dbg (hub->intfdev,
		"debounce: port %d: total %dms stable %dms status 0x%x\n",
		port1, total_time, stable_time, portstatus);

	if (stable_time < HUB_DEBOUNCE_STABLE)
		return -ETIMEDOUT;
	return portstatus;
}

static void ep0_reinit(struct usb_device *udev)
{
	usb_disable_endpoint(udev, 0 + USB_DIR_IN);
	usb_disable_endpoint(udev, 0 + USB_DIR_OUT);
	udev->ep_in[0] = udev->ep_out[0] = &udev->ep0;
}

#define usb_sndaddr0pipe()	(PIPE_CONTROL << 30)
#define usb_rcvaddr0pipe()	((PIPE_CONTROL << 30) | USB_DIR_IN)

static int hub_set_address(struct usb_device *udev)
{
	int retval;

	if (udev->devnum == 0)
		return -EINVAL;
	if (udev->state == USB_STATE_ADDRESS)
		return 0;
	if (udev->state != USB_STATE_DEFAULT)
		return -EINVAL;
	retval = usb_control_msg(udev, usb_sndaddr0pipe(),
		USB_REQ_SET_ADDRESS, 0, udev->devnum, 0,
		NULL, 0, USB_CTRL_SET_TIMEOUT);
	if (retval == 0) {
		usb_set_device_state(udev, USB_STATE_ADDRESS);
		ep0_reinit(udev);
	}
	return retval;
}

/* Reset device, (re)assign address, get device descriptor.
 * Device connection must be stable, no more debouncing needed.
 * Returns device in USB_STATE_ADDRESS, except on error.
 *
 * If this is called for an already-existing device (as part of
 * usb_reset_device), the caller must own the device lock.  For a
 * newly detected device that is not accessible through any global
 * pointers, it's not necessary to lock the device.
 */
static int
hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
		int retry_counter)
{
	static DECLARE_MUTEX(usb_address0_sem);

	struct usb_device	*hdev = hub->hdev;
	int			i, j, retval;
	unsigned		delay = HUB_SHORT_RESET_TIME;
	enum usb_device_speed	oldspeed = udev->speed;

	/* root hub ports have a slightly longer reset period
	 * (from USB 2.0 spec, section 7.1.7.5)
	 */
	if (!hdev->parent) {
		delay = HUB_ROOT_RESET_TIME;
		if (port1 == hdev->bus->otg_port)
			hdev->bus->b_hnp_enable = 0;
	}

	/* Some low speed devices have problems with the quick delay, so */
	/*  be a bit pessimistic with those devices. RHbug #23670 */
	if (oldspeed == USB_SPEED_LOW)
		delay = HUB_LONG_RESET_TIME;

	down(&usb_address0_sem);

	/* Reset the device; full speed may morph to high speed */
	retval = hub_port_reset(hub, port1, udev, delay);
	if (retval < 0)		/* error or disconnect */
		goto fail;
				/* success, speed is known */
	retval = -ENODEV;

	if (oldspeed != USB_SPEED_UNKNOWN && oldspeed != udev->speed) {
		dev_dbg(&udev->dev, "device reset changed speed!\n");
		goto fail;
	}
	oldspeed = udev->speed;
  
	/* USB 2.0 section 5.5.3 talks about ep0 maxpacket ...
	 * it's fixed size except for full speed devices.
	 */
	switch (udev->speed) {
	case USB_SPEED_HIGH:		/* fixed at 64 */
		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
		break;
	case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
		/* to determine the ep0 maxpacket size, try to read
		 * the device descriptor to get bMaxPacketSize0 and
		 * then correct our initial guess.
		 */
		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
		break;
	case USB_SPEED_LOW:		/* fixed at 8 */
		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(8);
		break;
	default:
		goto fail;
	}
 
	dev_info (&udev->dev,
			"%s %s speed USB device using %s and address %d\n",
			(udev->config) ? "reset" : "new",
			({ char *speed; switch (udev->speed) {
			case USB_SPEED_LOW:	speed = "low";	break;
			case USB_SPEED_FULL:	speed = "full";	break;
			case USB_SPEED_HIGH:	speed = "high";	break;
			default: 		speed = "?";	break;
			}; speed;}),
			udev->bus->controller->driver->name,
			udev->devnum);

	/* Set up TT records, if needed  */
	if (hdev->tt) {
		udev->tt = hdev->tt;
		udev->ttport = hdev->ttport;
	} else if (udev->speed != USB_SPEED_HIGH
			&& hdev->speed == USB_SPEED_HIGH) {
		udev->tt = &hub->tt;
		udev->ttport = port1;
	}
 
	/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way?
	 * Because device hardware and firmware is sometimes buggy in
	 * this area, and this is how Linux has done it for ages.
	 * Change it cautiously.
	 *
	 * NOTE:  If USE_NEW_SCHEME() is true we will start by issuing
	 * a 64-byte GET_DESCRIPTOR request.  This is what Windows does,
	 * so it may help with some non-standards-compliant devices.
	 * Otherwise we start with SET_ADDRESS and then try to read the
	 * first 8 bytes of the device descriptor to get the ep0 maxpacket
	 * value.
	 */
	for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
		if (USE_NEW_SCHEME(retry_counter)) {
			struct usb_device_descriptor *buf;
			int r = 0;

#define GET_DESCRIPTOR_BUFSIZE	64
			buf = kmalloc(GET_DESCRIPTOR_BUFSIZE, GFP_NOIO);
			if (!buf) {
				retval = -ENOMEM;
				continue;
			}

			/* Use a short timeout the first time through,
			 * so that recalcitrant full-speed devices with
			 * 8- or 16-byte ep0-maxpackets won't slow things
			 * down tremendously by NAKing the unexpectedly
			 * early status stage.  Also, retry on all errors;
			 * some devices are flakey.
			 */
			for (j = 0; j < 3; ++j) {
				buf->bMaxPacketSize0 = 0;
				r = usb_control_msg(udev, usb_rcvaddr0pipe(),
					USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
					USB_DT_DEVICE << 8, 0,
					buf, GET_DESCRIPTOR_BUFSIZE,
					(i ? USB_CTRL_GET_TIMEOUT : 1000));
				switch (buf->bMaxPacketSize0) {
				case 8: case 16: case 32: case 64:
					if (buf->bDescriptorType ==
							USB_DT_DEVICE) {
						r = 0;
						break;
					}
					/* FALL THROUGH */
				default:
					if (r == 0)
						r = -EPROTO;
					break;
				}
				if (r == 0)
					break;
			}
			udev->descriptor.bMaxPacketSize0 =
					buf->bMaxPacketSize0;
			kfree(buf);

			retval = hub_port_reset(hub, port1, udev, delay);
			if (retval < 0)		/* error or disconnect */
				goto fail;
			if (oldspeed != udev->speed) {
				dev_dbg(&udev->dev,
					"device reset changed speed!\n");
				retval = -ENODEV;
				goto fail;
			}
			if (r) {
				dev_err(&udev->dev, "device descriptor "
						"read/%s, error %d\n",
						"64", r);
				retval = -EMSGSIZE;
				continue;
			}
#undef GET_DESCRIPTOR_BUFSIZE
		}

		for (j = 0; j < SET_ADDRESS_TRIES; ++j) {
			retval = hub_set_address(udev);
			if (retval >= 0)
				break;
			msleep(200);
		}
		if (retval < 0) {
			dev_err(&udev->dev,
				"device not accepting address %d, error %d\n",
				udev->devnum, retval);
			goto fail;
		}
 
		/* cope with hardware quirkiness:
		 *  - let SET_ADDRESS settle, some device hardware wants it
		 *  - read ep0 maxpacket even for high and low speed,
  		 */
		msleep(10);
		if (USE_NEW_SCHEME(retry_counter))
			break;

		retval = usb_get_device_descriptor(udev, 8);
		if (retval < 8) {
			dev_err(&udev->dev, "device descriptor "
					"read/%s, error %d\n",
					"8", retval);
			if (retval >= 0)
				retval = -EMSGSIZE;
		} else {
			retval = 0;
			break;
		}
	}
	if (retval)
		goto fail;

	i = udev->descriptor.bMaxPacketSize0;
	if (le16_to_cpu(udev->ep0.desc.wMaxPacketSize) != i) {
		if (udev->speed != USB_SPEED_FULL ||
				!(i == 8 || i == 16 || i == 32 || i == 64)) {
			dev_err(&udev->dev, "ep0 maxpacket = %d\n", i);
			retval = -EMSGSIZE;
			goto fail;
		}
		dev_dbg(&udev->dev, "ep0 maxpacket = %d\n", i);
		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i);
		ep0_reinit(udev);
	}
  
	retval = usb_get_device_descriptor(udev, USB_DT_DEVICE_SIZE);
	if (retval < (signed)sizeof(udev->descriptor)) {
		dev_err(&udev->dev, "device descriptor read/%s, error %d\n",
			"all", retval);
		if (retval >= 0)
			retval = -ENOMSG;
		goto fail;
	}

	retval = 0;

fail:
	if (retval)
		hub_port_disable(hub, port1, 0);
	up(&usb_address0_sem);
	return retval;
}

static void
check_highspeed (struct usb_hub *hub, struct usb_device *udev, int port1)
{
	struct usb_qualifier_descriptor	*qual;
	int				status;

	qual = kmalloc (sizeof *qual, SLAB_KERNEL);
	if (qual == NULL)
		return;

	status = usb_get_descriptor (udev, USB_DT_DEVICE_QUALIFIER, 0,
			qual, sizeof *qual);
	if (status == sizeof *qual) {
		dev_info(&udev->dev, "not running at top speed; "
			"connect to a high speed hub\n");
		/* hub L