hub.c

h内核

	/* Try to allocate the next devnum beginning at bus->devnum_next. */
	devnum = find_next_zero_bit(bus->devmap.devicemap, 128,
			bus->devnum_next);
	if (devnum >= 128)
		devnum = find_next_zero_bit(bus->devmap.devicemap, 128, 1);

	bus->devnum_next = ( devnum >= 127 ? 1 : devnum + 1);

	if (devnum < 128) {
		set_bit(devnum, bus->devmap.devicemap);
		udev->devnum = devnum;
	}
}

static void release_address(struct usb_device *udev)
{
	if (udev->devnum > 0) {
		clear_bit(udev->devnum, udev->bus->devmap.devicemap);
		udev->devnum = -1;
	}
}

/**
 * usb_disconnect - disconnect a device (usbcore-internal)
 * @pdev: pointer to device being disconnected
 * Context: !in_interrupt ()
 *
 * Something got disconnected. Get rid of it and all of its children.
 *
 * If *pdev is a normal device then the parent hub must already be locked.
 * If *pdev is a root hub then this routine will acquire the
 * usb_bus_list_lock on behalf of the caller.
 *
 * Only hub drivers (including virtual root hub drivers for host
 * controllers) should ever call this.
 *
 * This call is synchronous, and may not be used in an interrupt context.
 */
void usb_disconnect(struct usb_device **pdev)
{
	struct usb_device	*udev = *pdev;
	int			i;

	if (!udev) {
		pr_debug ("%s nodev\n", __FUNCTION__);
		return;
	}

	/* mark the device as inactive, so any further urb submissions for
	 * this device (and any of its children) will fail immediately.
	 * this quiesces everyting except pending urbs.
	 */
	usb_set_device_state(udev, USB_STATE_NOTATTACHED);

	/* lock the bus list on behalf of HCDs unregistering their root hubs */
	if (!udev->parent) {
		down(&usb_bus_list_lock);
		usb_lock_device(udev);
	} else
		down(&udev->serialize);

	dev_info (&udev->dev, "USB disconnect, address %d\n", udev->devnum);

	/* Free up all the children before we remove this device */
	for (i = 0; i < USB_MAXCHILDREN; i++) {
		if (udev->children[i])
			usb_disconnect(&udev->children[i]);
	}

	/* deallocate hcd/hardware state ... nuking all pending urbs and
	 * cleaning up all state associated with the current configuration
	 * so that the hardware is now fully quiesced.
	 */
	usb_disable_device(udev, 0);

	/* Free the device number, remove the /proc/bus/usb entry and
	 * the sysfs attributes, and delete the parent's children[]
	 * (or root_hub) pointer.
	 */
	dev_dbg (&udev->dev, "unregistering device\n");
	release_address(udev);
	usbfs_remove_device(udev);
	usb_remove_sysfs_dev_files(udev);

	/* Avoid races with recursively_mark_NOTATTACHED() */
	spin_lock_irq(&device_state_lock);
	*pdev = NULL;
	spin_unlock_irq(&device_state_lock);

	if (!udev->parent) {
		usb_unlock_device(udev);
		up(&usb_bus_list_lock);
	} else
		up(&udev->serialize);

	device_unregister(&udev->dev);
}

static int choose_configuration(struct usb_device *udev)
{
	int c, i;

	/* NOTE: this should interact with hub power budgeting */

	c = udev->config[0].desc.bConfigurationValue;
	if (udev->descriptor.bNumConfigurations != 1) {
		for (i = 0; i < udev->descriptor.bNumConfigurations; i++) {
			struct usb_interface_descriptor	*desc;

			/* heuristic:  Linux is more likely to have class
			 * drivers, so avoid vendor-specific interfaces.
			 */
			desc = &udev->config[i].intf_cache[0]
					->altsetting->desc;
			if (desc->bInterfaceClass == USB_CLASS_VENDOR_SPEC)
				continue;
			/* COMM/2/all is CDC ACM, except 0xff is MSFT RNDIS.
			 * MSFT needs this to be the first config; never use
			 * it as the default unless Linux has host-side RNDIS.
			 * A second config would ideally be CDC-Ethernet, but
			 * may instead be the "vendor specific" CDC subset
			 * long used by ARM Linux for sa1100 or pxa255.
			 */
			if (desc->bInterfaceClass == USB_CLASS_COMM
					&& desc->bInterfaceSubClass == 2
					&& desc->bInterfaceProtocol == 0xff) {
				c = udev->config[1].desc.bConfigurationValue;
				continue;
			}
			c = udev->config[i].desc.bConfigurationValue;
			break;
		}
		dev_info(&udev->dev,
			"configuration #%d chosen from %d choices\n",
			c, udev->descriptor.bNumConfigurations);
	}
	return c;
}

#ifdef DEBUG
static void show_string(struct usb_device *udev, char *id, int index)
{
	char *buf;

	if (!index)
		return;
	if (!(buf = kmalloc(256, GFP_KERNEL)))
		return;
	if (usb_string(udev, index, buf, 256) > 0)
		dev_printk(KERN_INFO, &udev->dev, "%s: %s\n", id, buf);
	kfree(buf);
}

#else
static inline void show_string(struct usb_device *udev, char *id, int index)
{}
#endif

#ifdef	CONFIG_USB_OTG
#include "otg_whitelist.h"
#endif

/**
 * usb_new_device - perform initial device setup (usbcore-internal)
 * @udev: newly addressed device (in ADDRESS state)
 *
 * This is called with devices which have been enumerated, but not yet
 * configured.  The device descriptor is available, but not descriptors
 * for any device configuration.  The caller must have locked udev and
 * either the parent hub (if udev is a normal device) or else the
 * usb_bus_list_lock (if udev is a root hub).  The parent's pointer to
 * udev has already been installed, but udev is not yet visible through
 * sysfs or other filesystem code.
 *
 * Returns 0 for success (device is configured and listed, with its
 * interfaces, in sysfs); else a negative errno value.
 *
 * This call is synchronous, and may not be used in an interrupt context.
 *
 * Only the hub driver should ever call this; root hub registration
 * uses it indirectly.
 */
int usb_new_device(struct usb_device *udev)
{
	int err;
	int c;

	err = usb_get_configuration(udev);
	if (err < 0) {
		dev_err(&udev->dev, "can't read configurations, error %d\n",
			err);
		goto fail;
	}

	/* Tell the world! */
	dev_dbg(&udev->dev, "new device strings: Mfr=%d, Product=%d, "
			"SerialNumber=%d\n",
			udev->descriptor.iManufacturer,
			udev->descriptor.iProduct,
			udev->descriptor.iSerialNumber);

	if (udev->descriptor.iProduct)
		show_string(udev, "Product",
				udev->descriptor.iProduct);
	if (udev->descriptor.iManufacturer)
		show_string(udev, "Manufacturer",
				udev->descriptor.iManufacturer);
	if (udev->descriptor.iSerialNumber)
		show_string(udev, "SerialNumber",
				udev->descriptor.iSerialNumber);

#ifdef	CONFIG_USB_OTG
	/*
	 * OTG-aware devices on OTG-capable root hubs may be able to use SRP,
	 * to wake us after we've powered off VBUS; and HNP, switching roles
	 * "host" to "peripheral".  The OTG descriptor helps figure this out.
	 */
	if (!udev->bus->is_b_host
			&& udev->config
			&& udev->parent == udev->bus->root_hub) {
		struct usb_otg_descriptor	*desc = 0;
		struct usb_bus			*bus = udev->bus;

		/* descriptor may appear anywhere in config */
		if (__usb_get_extra_descriptor (udev->rawdescriptors[0],
					le16_to_cpu(udev->config[0].desc.wTotalLength),
					USB_DT_OTG, (void **) &desc) == 0) {
			if (desc->bmAttributes & USB_OTG_HNP) {
				unsigned		port1;
				struct usb_device	*root = udev->parent;
				
				for (port1 = 1; port1 <= root->maxchild;
						port1++) {
					if (root->children[port1-1] == udev)
						break;
				}

				dev_info(&udev->dev,
					"Dual-Role OTG device on %sHNP port\n",
					(port1 == bus->otg_port)
						? "" : "non-");

				/* enable HNP before suspend, it's simpler */
				if (port1 == bus->otg_port)
					bus->b_hnp_enable = 1;
				err = usb_control_msg(udev,
					usb_sndctrlpipe(udev, 0),
					USB_REQ_SET_FEATURE, 0,
					bus->b_hnp_enable
						? USB_DEVICE_B_HNP_ENABLE
						: USB_DEVICE_A_ALT_HNP_SUPPORT,
					0, NULL, 0, HZ * USB_CTRL_SET_TIMEOUT);
				if (err < 0) {
					/* OTG MESSAGE: report errors here,
					 * customize to match your product.
					 */
					dev_info(&udev->dev,
						"can't set HNP mode; %d\n",
						err);
					bus->b_hnp_enable = 0;
				}
			}
		}
	}

	if (!is_targeted(udev)) {

		/* Maybe it can talk to us, though we can't talk to it.
		 * (Includes HNP test device.)
		 */
		if (udev->bus->b_hnp_enable || udev->bus->is_b_host) {
			static int __usb_suspend_device (struct usb_device *,
						int port1, u32 state);
			err = __usb_suspend_device(udev,
					udev->bus->otg_port,
					PM_SUSPEND_MEM);
			if (err < 0)
				dev_dbg(&udev->dev, "HNP fail, %d\n", err);
		}
		err = -ENODEV;
		goto fail;
	}
#endif

	/* put device-specific files into sysfs */
	err = device_add (&udev->dev);
	if (err) {
		dev_err(&udev->dev, "can't device_add, error %d\n", err);
		goto fail;
	}
	usb_create_sysfs_dev_files (udev);

	/* choose and set the configuration. that registers the interfaces
	 * with the driver core, and lets usb device drivers bind to them.
	 */
	c = choose_configuration(udev);
	if (c < 0)
		dev_warn(&udev->dev,
				"can't choose an initial configuration\n");
	else {
		err = usb_set_configuration(udev, c);
		if (err) {
			dev_err(&udev->dev, "can't set config #%d, error %d\n",
					c, err);
			usb_remove_sysfs_dev_files(udev);
			device_del(&udev->dev);
			goto fail;
		}
	}

	/* USB device state == configured ... usable */

	/* add a /proc/bus/usb entry */
	usbfs_add_device(udev);
	return 0;

fail:
	usb_set_device_state(udev, USB_STATE_NOTATTACHED);
	return err;
}


static int hub_port_status(struct usb_hub *hub, int port1,
			       u16 *status, u16 *change)
{
	int ret;

	ret = get_port_status(hub->hdev, port1, &hub->status->port);
	if (ret < 0)
		dev_err (hub->intfdev,
			"%s failed (err = %d)\n", __FUNCTION__, ret);
	else {
		*status = le16_to_cpu(hub->status->port.wPortStatus);
		*change = le16_to_cpu(hub->status->port.wPortChange); 
		ret = 0;
	}
	return ret;
}

#define PORT_RESET_TRIES	5
#define SET_ADDRESS_TRIES	2
#define GET_DESCRIPTOR_TRIES	2
#define SET_CONFIG_TRIES	(2 * (use_both_schemes + 1))
#define USE_NEW_SCHEME(i)	((i) / 2 == old_scheme_first)

#define HUB_ROOT_RESET_TIME	50	/* times are in msec */
#define HUB_SHORT_RESET_TIME	10
#define HUB_LONG_RESET_TIME	200
#define HUB_RESET_TIMEOUT	500

static int hub_port_wait_reset(struct usb_hub *hub, int port1,
				struct usb_device *udev, unsigned int delay)
{
	int delay_time, ret;
	u16 portstatus;
	u16 portchange;

	for (delay_time = 0;
			delay_time < HUB_RESET_TIMEOUT;
			delay_time += delay) {
		/* wait to give the device a chance to reset */
		msleep(delay);

		/* read and decode port status */
		ret = hub_port_status(hub, port1, &portstatus, &portchange);
		if (ret < 0)
			return ret;

		/* Device went away? */
		if (!(portstatus & USB_PORT_STAT_CONNECTION))
			return -ENOTCONN;

		/* bomb out completely if something weird happened */
		if ((portchange & USB_PORT_STAT_C_CONNECTION))
			return -EINVAL;

		/* if we`ve finished resetting, then break out of the loop */
		if (!(portstatus & USB_PORT_STAT_RESET) &&
		    (portstatus & USB_PORT_STAT_ENABLE)) {
			if (portstatus & USB_PORT_STAT_HIGH_SPEED)
				udev->speed = USB_SPEED_HIGH;
			else if (portstatus & USB_PORT_STAT_LOW_SPEED)
				udev->speed = USB_SPEED_LOW;
			else
				udev->speed = USB_SPEED_FULL;
			return 0;
		}

		/* switch to the long delay after two short delay failures */
		if (delay_time >= 2 * HUB_SHORT_RESET_TIME)
			delay = HUB_LONG_RESET_TIME;

		dev_dbg (hub->intfdev,
			"port %d not reset yet, waiting %dms\n",
			port1, delay);
	}

	return -EBUSY;
}

static int hub_port_reset(struct usb_hub *hub, int port1,
				struct usb_device *udev, unsigned int delay)
{
	int i, status;

	/* Reset the port */
	for (i = 0; i < PORT_RESET_TRIES; i++) {
		status = set_port_feature(hub->hdev,
				port1, USB_PORT_FEAT_RESET);
		if (status)
			dev_err(hub->intfdev,
					"cannot reset port %d (err = %d)\n",
					port1, status);
		else
			status = hub_port_wait_reset(hub, port1, udev, delay);

		/* return on disconnect or reset */
		switch (status) {
		case 0:
			/* TRSTRCY = 10 ms */
			msleep(10);
			/* FALL THROUGH */
		case -ENOTCONN:
		case -ENODEV:
			clear_port_feature(hub->hdev,
				port1, USB_PORT_FEAT_C_RESET);
			/* FIXME need disconnect() for NOTATTACHED device */
			usb_set_device_state(udev, status
					? USB_STATE_NOTATTACHED
					: USB_STATE_DEFAULT);
			return status;
		}

		dev_dbg (hub->intfdev,
			"port %d not enabled, trying reset again...\n",
			port1);
		delay = HUB_LONG_RESET_TIME;
	}

	dev_err (hub->intfdev,
		"Cannot enable port %i.  Maybe the USB cable is bad?\n",
		port1);

	return status;
}

static int hub_port_disable(struct usb_hub *hub, int port1, int set_state)
{
	struct usb_device *hdev = hub->hdev;
	int ret;

	if (hdev->children[port1-1] && set_state) {
		usb_set_device_state(hdev->children[port1-1],
				USB_STATE_NOTATTACHED);
	}
	ret = clear_port_feature(hdev, port1, USB_PORT_FEAT_ENABLE);
	if (ret)
		dev_err(hub->intfdev, "cannot disable port %d (err = %d)\n",
			port1, ret);

	return ret;
}

/*
 * Disable a port and mark a logical connnect-change event, so that some
 * time later khubd will disconnect() any existing usb_device on the port
 * and will re-enumerate if there actually is a device attached.
 */
static void hub_port_logical_disconnect(struct usb_hub *hub, int port1)
{
	dev_dbg(hub->intfdev, "logical disconnect on port %d\n", port1);
	hub_port_disable(hub, port1, 1);

	/* FIXME let caller ask to power down the port:
	 *  - some devices won't enumerate without a VBUS power cycle
	 *  - SRP saves power that way
	 *  - usb_suspend_device(dev,PM_SUSPEND_DISK)
	 * That's easy if this hub can switch power per-port, and
	 * khubd reactivates the port later (timer, SRP, etc).
	 * Powerdown must be optional, because of reset/DFU.
	 */