hub.c

S3C2440ARM9开发板的USB驱动程序

		if (!(portstatus & USB_PORT_STAT_CONNECTION))
			return 1;

		/* bomb out completely if something weird happened */
		if ((portchange & USB_PORT_STAT_C_CONNECTION))
			return -1;

		/* 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)
				dev->speed = USB_SPEED_HIGH;
			else if (portstatus & USB_PORT_STAT_LOW_SPEED)
				dev->speed = USB_SPEED_LOW;
			else
				dev->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;

		dbg("port %d of hub %d not reset yet, waiting %dms", port + 1,
			hub->devnum, delay);
	}

	return -1;
}

/* return: -1 on error, 0 on success, 1 on disconnect.  */
static int usb_hub_port_reset(struct usb_device *hub, int port,
				struct usb_device *dev, unsigned int delay)
{
	int i, status;

	/* Reset the port */
	for (i = 0; i < HUB_RESET_TRIES; i++) {
		usb_set_port_feature(hub, port + 1, USB_PORT_FEAT_RESET);

		/* return on disconnect or reset */
		status = usb_hub_port_wait_reset(hub, port, dev, delay);
		if (status != -1) {
			usb_clear_port_feature(hub, port + 1, USB_PORT_FEAT_C_RESET);
			return status;
		}

		dbg("port %d of hub %d not enabled, trying reset again...",
			port + 1, hub->devnum);
		delay = HUB_LONG_RESET_TIME;
	}

	err("Cannot enable port %i of hub %d, disabling port.",
		port + 1, hub->devnum);
	err("Maybe the USB cable is bad?");

	return -1;
}

void usb_hub_port_disable(struct usb_device *hub, int port)
{
	int ret;

	ret = usb_clear_port_feature(hub, port + 1, USB_PORT_FEAT_ENABLE);
	if (ret)
		err("cannot disable port %d of hub %d (err = %d)",
			port + 1, hub->devnum, ret);
}

/* 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 which require longer delays of about 200-400ms.
 * Not covered by the spec - but easy to deal with.
 *
 * This implementation uses 400ms minimum debounce timeout and checks
 * every 100ms for transient disconnects to restart the delay.
 */

#define HUB_DEBOUNCE_TIMEOUT	400
#define HUB_DEBOUNCE_STEP	100

/* return: -1 on error, 0 on success, 1 on disconnect.  */
static int usb_hub_port_debounce(struct usb_device *hub, int port)
{
	int ret;
	unsigned delay_time;
	u16 portchange, portstatus;

	for (delay_time = 0; delay_time < HUB_DEBOUNCE_TIMEOUT; /* empty */ ) {

		/* wait debounce step increment */
		wait_ms(HUB_DEBOUNCE_STEP);

		ret = usb_hub_port_status(hub, port, &portstatus, &portchange);
		if (ret < 0)
			return -1;

		if ((portchange & USB_PORT_STAT_C_CONNECTION)) {
			usb_clear_port_feature(hub, port+1, USB_PORT_FEAT_C_CONNECTION);
			delay_time = 0;
		}
		else
			delay_time += HUB_DEBOUNCE_STEP;
	}
	return ((portstatus&USB_PORT_STAT_CONNECTION)) ? 0 : 1;
}

static void usb_hub_port_connect_change(struct usb_hub *hubstate, int port,
					u16 portstatus, u16 portchange)
{
	struct usb_device *hub = hubstate->dev;
	struct usb_device *dev;
	unsigned int delay = HUB_SHORT_RESET_TIME;
	int i;

	dbg("port %d, portstatus %x, change %x, %s",
		port + 1, portstatus, portchange, portspeed (portstatus));

	/* Clear the connection change status */
	usb_clear_port_feature(hub, port + 1, USB_PORT_FEAT_C_CONNECTION);

	/* Disconnect any existing devices under this port */
	if (hub->children[port])
		usb_disconnect(&hub->children[port]);

	/* Return now if nothing is connected */
	if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
		if (portstatus & USB_PORT_STAT_ENABLE)
			usb_hub_port_disable(hub, port);

		return;
	}

	if (usb_hub_port_debounce(hub, port)) {
		err("connect-debounce failed, port %d disabled", port+1);
		usb_hub_port_disable(hub, port);
		return;
	}

	down(&usb_address0_sem);

	for (i = 0; i < HUB_PROBE_TRIES; i++) {
		struct usb_device *pdev;
		int len;

		/* Allocate a new device struct */
		dev = usb_alloc_dev(hub, hub->bus);
		if (!dev) {
			err("couldn't allocate usb_device");
			break;
		}

		hub->children[port] = dev;

		/* Reset the device */
		if (usb_hub_port_reset(hub, port, dev, delay)) {
			usb_free_dev(dev);
			break;
		}

		/* Find a new device ID for it */
		usb_connect(dev);

		/* Set up TT records, if needed  */
		if (hub->tt) {
			dev->tt = hub->tt;
			dev->ttport = hub->ttport;
		} else if (dev->speed != USB_SPEED_HIGH
				&& hub->speed == USB_SPEED_HIGH) {
			dev->tt = &hubstate->tt;
			dev->ttport = port + 1;
		}

		/* Save readable and stable topology id, distinguishing
		 * devices by location for diagnostics, tools, etc.  The
		 * string is a path along hub ports, from the root.  Each
		 * device's id will be stable until USB is re-cabled, and
		 * hubs are often labeled with these port numbers.
		 *
		 * Initial size: ".NN" times five hubs + NUL = 16 bytes max
		 * (quite rare, since most hubs have 4-6 ports).
		 */
		pdev = dev->parent;
		if (pdev->devpath [0] != '0')	/* parent not root? */
			len = snprintf (dev->devpath, sizeof dev->devpath,
				"%s.%d", pdev->devpath, port + 1);
		/* root == "0", root port 2 == "2", port 3 that hub "2.3" */
		else
			len = snprintf (dev->devpath, sizeof dev->devpath,
				"%d", port + 1);
		if (len == sizeof dev->devpath)
			warn ("devpath size! usb/%03d/%03d path %s",
				dev->bus->busnum, dev->devnum, dev->devpath);
		info("new USB device %s-%s, assigned address %d",
			dev->bus->bus_name, dev->devpath, dev->devnum);

		/* Run it through the hoops (find a driver, etc) */
		if (!usb_new_device(dev))
			goto done;

		/* Free the configuration if there was an error */
		usb_free_dev(dev);

		/* Switch to a long reset time */
		delay = HUB_LONG_RESET_TIME;
	}

	hub->children[port] = NULL;
	usb_hub_port_disable(hub, port);
done:
	up(&usb_address0_sem);
}

static void usb_hub_events(void)
{
	unsigned long flags;
	struct list_head *tmp;
	struct usb_device *dev;
	struct usb_hub *hub;
	struct usb_hub_status *hubsts;
	u16 hubstatus;
	u16 hubchange;
	u16 portstatus;
	u16 portchange;
	int i, ret;

	/*
	 *  We restart the list everytime to avoid a deadlock with
	 * deleting hubs downstream from this one. This should be
	 * safe since we delete the hub from the event list.
	 * Not the most efficient, but avoids deadlocks.
	 */
	while (1) {
		spin_lock_irqsave(&hub_event_lock, flags);

		if (list_empty(&hub_event_list))
			break;

		/* Grab the next entry from the beginning of the list */
		tmp = hub_event_list.next;

		hub = list_entry(tmp, struct usb_hub, event_list);
		dev = hub->dev;

		list_del(tmp);
		INIT_LIST_HEAD(tmp);

		down(&hub->khubd_sem); /* never blocks, we were on list */
		spin_unlock_irqrestore(&hub_event_lock, flags);

		if (hub->error) {
			dbg("resetting hub %d for error %d", dev->devnum, hub->error);

			if (usb_hub_reset(hub)) {
				err("error resetting hub %d - disconnecting", dev->devnum);
				up(&hub->khubd_sem);
				usb_hub_disconnect(dev);
				continue;
			}

			hub->nerrors = 0;
			hub->error = 0;
		}

		for (i = 0; i < hub->descriptor->bNbrPorts; i++) {
			ret = usb_hub_port_status(dev, i, &portstatus, &portchange);
			if (ret < 0) {
				continue;
			}

			if (portchange & USB_PORT_STAT_C_CONNECTION) {
				dbg("port %d connection change", i + 1);

				usb_hub_port_connect_change(hub, i, portstatus, portchange);
			} else if (portchange & USB_PORT_STAT_C_ENABLE) {
				dbg("port %d enable change, status %x", i + 1, portstatus);
				usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_C_ENABLE);

				/*
				 * EM interference sometimes causes bad shielded USB devices to 
				 * be shutdown by the hub, this hack enables them again.
				 * Works at least with mouse driver. 
				 */
				if (!(portstatus & USB_PORT_STAT_ENABLE) && 
				    (portstatus & USB_PORT_STAT_CONNECTION) && (dev->children[i])) {
					err("already running port %i disabled by hub (EMI?), re-enabling...",
						i + 1);
					usb_hub_port_connect_change(hub, i, portstatus, portchange);
				}
			}

			if (portchange & USB_PORT_STAT_C_SUSPEND) {
				dbg("port %d suspend change", i + 1);
				usb_clear_port_feature(dev, i + 1,  USB_PORT_FEAT_C_SUSPEND);
			}
			
			if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
				err("port %d over-current change", i + 1);
				usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_C_OVER_CURRENT);
				usb_hub_power_on(hub);
			}

			if (portchange & USB_PORT_STAT_C_RESET) {
				dbg("port %d reset change", i + 1);
				usb_clear_port_feature(dev, i + 1, USB_PORT_FEAT_C_RESET);
			}
		} /* end for i */

		/* deal with hub status changes */
		hubsts = kmalloc(sizeof *hubsts, GFP_KERNEL);
		if (!hubsts) {
			err("couldn't allocate hubsts");
		} else {
			if (usb_get_hub_status(dev, hubsts) < 0)
				err("get_hub_status failed");
			else {
				hubstatus = le16_to_cpup(&hubsts->wHubStatus);
				hubchange = le16_to_cpup(&hubsts->wHubChange);
				if (hubchange & HUB_CHANGE_LOCAL_POWER) {
					dbg("hub power change");
					usb_clear_hub_feature(dev, C_HUB_LOCAL_POWER);
				}
				if (hubchange & HUB_CHANGE_OVERCURRENT) {
					dbg("hub overcurrent change");
					wait_ms(500);	/* Cool down */
					usb_clear_hub_feature(dev, C_HUB_OVER_CURRENT);
					usb_hub_power_on(hub);
				}
			}
			kfree(hubsts);
		}
		up(&hub->khubd_sem);
        } /* end while (1) */

	spin_unlock_irqrestore(&hub_event_lock, flags);
}

static int usb_hub_thread(void *__hub)
{
	lock_kernel();

	/*
	 * This thread doesn't need any user-level access,
	 * so get rid of all our resources
	 */

	daemonize();
	reparent_to_init();

	/* Setup a nice name */
	strcpy(current->comm, "khubd");

	/* Send me a signal to get me die (for debugging) */
	do {
		usb_hub_events();
		wait_event_interruptible(khubd_wait, !list_empty(&hub_event_list)); 
	} while (!signal_pending(current));

	dbg("usb_hub_thread exiting");

	unlock_kernel();
	complete_and_exit(&khubd_exited, 0);
}

static struct usb_device_id hub_id_table [] = {
    { match_flags: USB_DEVICE_ID_MATCH_INT_CLASS,
      bInterfaceClass: USB_CLASS_HUB},
    { }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, hub_id_table);

static struct usb_driver hub_driver = {
	name:		"hub",
	probe:		hub_probe,
	ioctl:		hub_ioctl,
	disconnect:	hub_disconnect,
	id_table:	hub_id_table,
};

/*
 * This should be a separate module.
 */
int usb_hub_init(void)
{
	int pid;

	if (usb_register(&hub_driver) < 0) {
		err("Unable to register USB hub driver");
		return -1;
	}

	pid = kernel_thread(usb_hub_thread, NULL,
		CLONE_FS | CLONE_FILES | CLONE_SIGHAND);
	if (pid >= 0) {
		khubd_pid = pid;

		return 0;
	}

	/* Fall through if kernel_thread failed */
	usb_deregister(&hub_driver);
	err("failed to start usb_hub_thread");

	return -1;
}

void usb_hub_cleanup(void)
{
	int ret;

	/* Kill the thread */
	ret = kill_proc(khubd_pid, SIGTERM, 1);

	wait_for_completion(&khubd_exited);

	/*
	 * Hub resources are freed for us by usb_deregister. It calls
	 * usb_driver_purge on every device which in turn calls that
	 * devices disconnect function if it is using this driver.
	 * The hub_disconnect function takes care of releasing the
	 * individual hub resources. -greg
	 */
	usb_deregister(&hub_driver);
} /* usb_hub_cleanup() */

/*
 * WARNING - If a driver calls usb_reset_device, you should simulate a
 * disconnect() and probe() for other interfaces you doesn't claim. This
 * is left up to the driver writer right now. This insures other drivers
 * have a chance to re-setup their interface.
 *
 * Take a look at proc_resetdevice in devio.c for some sample code to
 * do this.
 */
int usb_reset_device(struct usb_device *dev)
{
	struct usb_device *parent = dev->parent;
	struct usb_device_descriptor *descriptor;
	int i, ret, port = -1;

	if (!parent) {
		err("attempting to reset root hub!");
		return -EINVAL;
	}

	for (i = 0; i < parent->maxchild; i++)
		if (parent->children[i] == dev) {
			port = i;
			break;
		}

	if (port < 0)
		return -ENOENT;

	down(&usb_address0_sem);

	/* Send a reset to the device */
	if (usb_hub_port_reset(parent, port, dev, HUB_SHORT_RESET_TIME)) {
		usb_hub_port_disable(parent, port);
		up(&usb_address0_sem);
		return(-ENODEV);
	}

	/* Reprogram the Address */
	ret = usb_set_address(dev);
	if (ret < 0) {
		err("USB device not accepting new address (error=%d)", ret);
		usb_hub_port_disable(parent, port);
		up(&usb_address0_sem);
		return ret;
	}

	/* Let the SET_ADDRESS settle */
	wait_ms(10);

	up(&usb_address0_sem);

	/*
	 * Now we fetch the configuration descriptors for the device and
	 * see if anything has changed. If it has, we dump the current
	 * parsed descriptors and reparse from scratch. Then we leave
	 * the device alone for the caller to finish setting up.
	 *
	 * If nothing changed, we reprogram the configuration and then
	 * the alternate settings.
	 */
	descriptor = kmalloc(sizeof *descriptor, GFP_NOIO);
	if (!descriptor) {
		return -ENOMEM;
	}
	ret = usb_get_descriptor(dev, USB_DT_DEVICE, 0, descriptor,
			sizeof(*descriptor));
	if (ret < 0)
		return ret;

	le16_to_cpus(&descriptor->bcdUSB);
	le16_to_cpus(&descriptor->idVendor);
	le16_to_cpus(&descriptor->idProduct);
	le16_to_cpus(&descriptor->bcdDevice);

	if (memcmp(&dev->descriptor, descriptor, sizeof(*descriptor))) {
		kfree(descriptor);
		usb_destroy_configuration(dev);

		ret = usb_get_device_descriptor(dev);
		if (ret < sizeof(dev->descriptor)) {
			if (ret < 0)
				err("unable to get device descriptor (error=%d)", ret);
			else
				err("USB device descriptor short read (expected %Zi, got %i)", sizeof(dev->descriptor), ret);
        
			clear_bit(dev->devnum, &dev->bus->devmap.devicemap);
			dev->devnum = -1;
			return -EIO;
		}

		ret = usb_get_configuration(dev);
		if (ret < 0) {
			err("unable to get configuration (error=%d)", ret);
			usb_destroy_configuration(dev);
			clear_bit(dev->devnum, &dev->bus->devmap.devicemap);
			dev->devnum = -1;
			return 1;
		}

		dev->actconfig = dev->config;
		usb_set_maxpacket(dev);

		return 1;
	}

	kfree(descriptor);

	ret = usb_set_configuration(dev, dev->actconfig->bConfigurationValue);
	if (ret < 0) {
		err("failed to set active configuration (error=%d)", ret);
		return ret;
	}

	for (i = 0; i < dev->actconfig->bNumInterfaces; i++) {
		struct usb_interface *intf = &dev->actconfig->interface[i];
		struct usb_interface_descriptor *as = &intf->altsetting[intf->act_altsetting];

		ret = usb_set_interface(dev, as->bInterfaceNumber, as->bAlternateSetting);
		if (ret < 0) {
			err("failed to set active alternate setting for interface %d (error=%d)", i, ret);
			return ret;
		}
	}

	return 0;
}