vhci_hcd.c

Realize the usbip function, which could be simulate usb port through net

			case USB_REQ_GET_DESCRIPTOR:
				if (ctrlreq->wValue == (USB_DT_DEVICE << 8))
					dbg_vhci_hc("Not yet?: Get_Descriptor to device 0 (get max pipe size)\n");

				vdev->udev = urb->dev;
				goto out;

			default:
				/* NOT REACHED */
				uerr("invalid request to devnum 0 bRequest %u, wValue %u\n",
						ctrlreq->bRequest, ctrlreq->wValue);
				ret =  -EINVAL;
				goto no_need_xmit;
		}

	}

out:


	vhci_tx_urb(urb);


	spin_unlock_irqrestore(&the_controller->lock, flags);

	return 0;


no_need_xmit:

	spin_unlock_irqrestore(&the_controller->lock, flags);
	usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb);

	return 0;
}


/*
 * vhci_rx gives back the urb after receiving the reply of the urb.  If an
 * unlink pdu is sent or not, vhci_rx receives a normal return pdu and gives
 * back its urb. For the driver unlinking the urb, the content of the urb is
 * not important, but the calling to its completion handler is important; the
 * completion of unlinking is notified by the completion handler.
 *
 *
 * CLIENT SIDE
 *
 * - When vhci_hcd receives RET_SUBMIT,
 *
 *	- case 1a). the urb of the pdu is not unlinking.
 *		- normal case
 *		=> just give back the urb
 *
 *	- case 1b). the urb of the pdu is unlinking.
 *		- usbip.ko will return a reply of the unlinking request.
 *		=> give back the urb now and go to case 2b).
 *
 * - When vhci_hcd receives RET_UNLINK,
 *
 *	- case 2a). a submit request is still pending in vhci_hcd.
 *		- urb was really pending in usbip.ko and urb_unlink_urb() was
 *		  completed there.
 *		=> free a pending submit request
 *		=> notify unlink completeness by giving back the urb
 *
 *	- case 2b). a submit request is *not* pending in vhci_hcd.
 *		- urb was already given back to the core driver.
 *		=> do not give back the urb
 *
 *
 * SERVER SIDE
 *
 * - When usbip receives CMD_UNLINK,
 *
 *	- case 3a). the urb of the unlink request is now in submission.
 *		=> do usb_unlink_urb().
 *		=> after the unlink is completed, send RET_UNLINK.
 *
 *	- case 3b). the urb of the unlink request is not in submission.
 *		- may be already completed or never be received
 *		=> send RET_UNLINK
 *
 */
static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
{
	unsigned long flags;
	struct vhci_priv *priv;
	struct vhci_device *vdev;

	uinfo("vhci_hcd: dequeue a urb %p\n", urb);


	spin_lock_irqsave(&the_controller->lock, flags);

	priv = urb->hcpriv;
	if (!priv) {
		/* URB was never linked! or will be soon given back by vhci_rx. */
		spin_unlock_irqrestore(&the_controller->lock, flags);
		return 0;
	}

	 /* send unlink request here? */
	vdev = priv->vdev;

	if (!vdev->ud.tcp_socket) {
		/* tcp connection is closed */
		unsigned long flags2;

		spin_lock_irqsave(&vdev->priv_lock, flags2);

		uinfo("vhci_hcd: device %p seems to be disconnected\n", vdev);
		list_del(&priv->list);
		kfree(priv);
		urb->hcpriv = NULL;

		spin_unlock_irqrestore(&vdev->priv_lock, flags2);

	} else {
		/* tcp connection is alive */
		unsigned long flags2;
		struct vhci_unlink *unlink;

		spin_lock_irqsave(&vdev->priv_lock, flags2);

		/* setup CMD_UNLINK pdu */
		unlink = kzalloc(sizeof(struct vhci_unlink), GFP_ATOMIC);
		if (!unlink) {
			uerr("malloc vhci_unlink\n");
			spin_unlock_irqrestore(&vdev->priv_lock, flags2);
			spin_unlock_irqrestore(&the_controller->lock, flags);
			usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_MALLOC);
			return -ENOMEM;
		}

		unlink->seqnum = atomic_inc_return(&the_controller->seqnum);
		if (unlink->seqnum == 0xffff)
			uinfo("seqnum max\n");

		unlink->unlink_seqnum = priv->seqnum;

		uinfo("vhci_hcd: device %p seems to be still connected\n", vdev);

		/* send cmd_unlink and try to cancel the pending URB in the peer */
		list_add_tail(&unlink->list, &vdev->unlink_tx);
		wake_up(&vdev->waitq_tx);

		spin_unlock_irqrestore(&vdev->priv_lock, flags2);
	}

	spin_unlock_irqrestore(&the_controller->lock, flags);

	/*
	 * If tcp connection is alive, we have sent CMD_UNLINK.
	 * vhci_rx will receive RET_UNLINK and giveb back the URB.
	 * Otherwise, we give back it here.
	 */
	if (!vdev->ud.tcp_socket) {
		/* tcp connection is closed */
		uinfo("vhci_hcd: vhci_urb_dequeue() gives back urb %p\n", urb);
		usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb);
	}

	dbg_vhci_hc("leave\n");
	return 0;
}


static void vhci_device_unlink_cleanup(struct vhci_device *vdev)
{
	struct vhci_unlink *unlink, *tmp;

	spin_lock(&vdev->priv_lock);

	list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) {
		list_del(&unlink->list);
		kfree(unlink);
	}

	list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
		list_del(&unlink->list);
		kfree(unlink);
	}

	spin_unlock(&vdev->priv_lock);
}

/*
 * The important thing is that only one context begins cleanup.
 * This is why error handling and cleanup become simple.
 * We do not want to consider race condition as possible.
 */
static void vhci_shutdown_connection(struct usbip_device *ud)
{
	struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);

	/* need this? see stub_dev.c */
	if (ud->tcp_socket) {
		udbg("shutdown tcp_socket %p\n", ud->tcp_socket);
		ud->tcp_socket->ops->shutdown(ud->tcp_socket,
				RCV_SHUTDOWN|SEND_SHUTDOWN);
	}

	usbip_stop_threads(&vdev->ud);
	uinfo("stop threads\n");

	/* active connection is closed */
	if (vdev->ud.tcp_socket != NULL) {
		sock_release(vdev->ud.tcp_socket);
		vdev->ud.tcp_socket = NULL;
	}
	uinfo("release socket\n");

	vhci_device_unlink_cleanup(vdev);

	/*
	 * rh_port_disconnect() is a trigger of ...
	 *   usb_disable_device():
	 *	disable all the endpoints for a USB device.
	 *   usb_disable_endpoint():
	 *	disable endpoints. pending urbs are unlinked(dequeued).
	 *
	 * NOTE: After calling rh_port_disconnect(), the USB device drivers of a
	 * deteched device should release used urbs in a cleanup function(i.e.
	 * xxx_disconnect()). Therefore, vhci_hcd does not need to release
	 * pushed urbs and their private data in this function.
	 *
	 * NOTE: vhci_dequeue() must be considered carefully. When shutdowning
	 * a connection, vhci_shutdown_connection() expects vhci_dequeue()
	 * gives back pushed urbs and frees their private data by request of
	 * the cleanup function of a USB driver. When unlinking a urb with an
	 * active connection, vhci_dequeue() does not give back the urb which
	 * is actually given back by vhci_rx after receiving its return pdu.
	 *
	 */
	rh_port_disconnect(vdev->rhport);

	uinfo("disconnect device\n");
}


static void vhci_device_reset(struct usbip_device *ud)
{
	struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);

	spin_lock(&ud->lock);

	vdev->busnum = 0;
	vdev->devnum = 0;
	vdev->speed  = 0;

	ud->tcp_socket = NULL;

	ud->status = VDEV_ST_NULL;

	spin_unlock(&ud->lock);
}

static void vhci_device_unusable(struct usbip_device* ud)
{
	spin_lock(&ud->lock);

	ud->status = VDEV_ST_ERROR;

	spin_unlock(&ud->lock);
}

static void vhci_device_init(struct vhci_device *vdev)
{
	memset(vdev, 0, sizeof(*vdev));

	usbip_task_init(&vdev->ud.tcp_rx, "vhci_rx", vhci_rx_loop);
	usbip_task_init(&vdev->ud.tcp_tx, "vhci_tx", vhci_tx_loop);

	vdev->ud.side   = USBIP_VHCI;
	vdev->ud.status = VDEV_ST_NULL;
	// vdev->ud.lock   = SPIN_LOCK_UNLOCKED;
	spin_lock_init(&vdev->ud.lock);

	INIT_LIST_HEAD(&vdev->priv_rx);
	INIT_LIST_HEAD(&vdev->priv_tx);
	INIT_LIST_HEAD(&vdev->unlink_tx);
	INIT_LIST_HEAD(&vdev->unlink_rx);
	// vdev->priv_lock = SPIN_LOCK_UNLOCKED;
	spin_lock_init(&vdev->priv_lock);

	init_waitqueue_head(&vdev->waitq_tx);

	vdev->ud.eh_ops.shutdown = vhci_shutdown_connection;
	vdev->ud.eh_ops.reset = vhci_device_reset;
	vdev->ud.eh_ops.unusable= vhci_device_unusable;

	usbip_start_eh(&vdev->ud);
}


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

static int vhci_start(struct usb_hcd *hcd)
{
	struct vhci_hcd *vhci = hcd_to_vhci(hcd);
	int rhport;
	int err = 0;

	dbg_vhci_hc("enter vhci_start\n");


	/* initialize private data of usb_hcd */

	for(rhport=0; rhport < VHCI_NPORTS; rhport++) {
		struct vhci_device *vdev = &vhci->vdev[rhport];
		vhci_device_init(vdev);
		vdev->rhport = rhport;
	}

	atomic_set(&vhci->seqnum, 0);
	spin_lock_init(&vhci->lock);



	//hcd->power_budget = 0; /* no limit ? */
	hcd->state  = HC_STATE_RUNNING;
	//hcd->uses_new_polling = 1;


	/* vhci_hcd is now ready to be controlled through sysfs */
	err = sysfs_create_group(&vhci_dev(vhci)->kobj, &dev_attr_group);
	if (err) {
		uerr("create sysfs files\n");
		return err;
	}

	return 0;
}

static void vhci_stop(struct usb_hcd *hcd)
{
	struct vhci_hcd *vhci = hcd_to_vhci(hcd);
	int rhport = 0;

	dbg_vhci_hc("stop VHCI controller\n");


	/* 1. remove the userland interface of vhci_hcd */
	sysfs_remove_group(&vhci_dev(vhci)->kobj, &dev_attr_group);

	/* 2. shutdown all the ports of vhci_hcd */
	for(rhport = 0 ; rhport < VHCI_NPORTS; rhport++) {
		struct vhci_device *vdev = &vhci->vdev[rhport];

		usbip_event_add(&vdev->ud, VDEV_EVENT_REMOVED);
		usbip_stop_eh(&vdev->ud);
	}


	uinfo("vhci_stop done\n");
}

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

static int vhci_get_frame_number(struct usb_hcd *hcd)
{
	uerr("Not yet implemented\n");
	return 0;
}


#ifdef  CONFIG_PM

static int vhci_bus_suspend(struct usb_hcd *hcd)
{
	dbg("%s\n", __FUNCTION__);
	return 0;
}

static int vhci_bus_resume(struct usb_hcd *hcd)
{
	dbg("%s\n", __FUNCTION__);
	return 0;
}

#else

#define vhci_bus_suspend      NULL
#define vhci_bus_resume       NULL
#endif



static struct hc_driver vhci_hc_driver = {
	.description	= driver_name,
	.product_desc	= driver_desc,
	.hcd_priv_size	= sizeof(struct vhci_hcd),

	.flags		= HCD_USB2,

	.start		= vhci_start,
	.stop 		= vhci_stop,

	.urb_enqueue	= vhci_urb_enqueue,
	.urb_dequeue	= vhci_urb_dequeue,

	.get_frame_number = vhci_get_frame_number,

	.hub_status_data = vhci_hub_status,
	.hub_control    = vhci_hub_control,
	.bus_suspend	= vhci_bus_suspend,
	.bus_resume	= vhci_bus_resume,
};

static int vhci_hcd_probe(struct platform_device *pdev)
{
	struct usb_hcd		*hcd;
	int			ret;

	uinfo("proving...\n");

	dbg_vhci_hc("name %s id %d\n", pdev->name, pdev->id);


	/* will be removed */
	if (pdev->dev.dma_mask) {
		info("vhci_hcd DMA not supported\n");
		return -EINVAL;
	}


	/*
	 * Allocate and initialize hcd.
	 * Our private data is also allocated automatically.
	 */
	hcd = usb_create_hcd(&vhci_hc_driver, &pdev->dev, pdev->dev.bus_id);
	if (!hcd) {
		uerr("create hcd failed\n");
		return -ENOMEM;
	}


	/* this is private data for vhci_hcd */
	the_controller = hcd_to_vhci(hcd);

	/*
	 * Finish generic HCD structure initialization and register.
	 * Call the driver's reset() and start() routines.
	 */
	ret = usb_add_hcd(hcd, 0, 0);
	if (ret != 0) {
		uerr("usb_add_hcd failed %d\n", ret);
		usb_put_hcd(hcd);
		the_controller = NULL;
		return ret;
	}


	dbg_vhci_hc("bye\n");
	return 0;
}


static int vhci_hcd_remove(struct platform_device *pdev)
{
	struct usb_hcd	*hcd;


	hcd = platform_get_drvdata(pdev);
	if(!hcd)
		return 0;

	/*
	 * Disconnects the root hub,
	 * then reverses the effects of usb_add_hcd(),
	 * invoking the HCD's stop() methods.
	 */
	usb_remove_hcd(hcd);
	usb_put_hcd(hcd);
	the_controller = NULL;


	return 0;
}



#ifdef CONFIG_PM

/* what should happen for USB/IP under suspend/resume? */
static int vhci_hcd_suspend(struct platform_device *pdev, pm_message_t state)
{
	dev_dbg(&pdev->dev, "%s\n", __FUNCTION__);

	pdev->dev.power.power_state = state;

	return 0;
}

static int vhci_hcd_resume(struct platform_device *pdev)
{
	dev_dbg(&pdev->dev, "%s\n", __FUNCTION__);

	pdev->dev.power.power_state = PMSG_ON;

	return 0;
}

#else

#define vhci_hcd_suspend	NULL
#define vhci_hcd_resume		NULL

#endif


static struct platform_driver vhci_driver = {
	.probe	= vhci_hcd_probe,
	.remove	= __devexit_p(vhci_hcd_remove),
	.suspend = vhci_hcd_suspend,
	.resume	= vhci_hcd_resume,
	.driver	= {
		.name = (char *) driver_name,
		.owner = THIS_MODULE,
	},
};

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

/*
 * The VHCI 'device' is 'virtual'; not a real plug&play hardware.
 * We need to add this virtual device as a platform device arbitrarily:
 *	1. platform_device_register()
 */
static void the_pdev_release(struct device *dev)
{
	return;
}

static struct platform_device the_pdev = {
	/* should be the same name as driver_name */
	.name = (char *) driver_name,
	.id = -1,
	.dev = {
		//.driver = &vhci_driver,
		.release = the_pdev_release,
	},
};

static int __init vhci_init(void)
{
	int ret;

	dbg_vhci_hc("enter\n");
	if (usb_disabled())
		return -ENODEV;

	info("driver %s, %s\n", driver_name, DRIVER_VERSION);

	ret = platform_driver_register(&vhci_driver);
	if (ret < 0)
		goto err_driver_register;

	ret = platform_device_register(&the_pdev);
	if (ret < 0)
		goto err_platform_device_register;


	dbg_vhci_hc("bye\n");
	return ret;



	/* error occurred */

err_platform_device_register:
	platform_driver_unregister(&vhci_driver);

err_driver_register:

	dbg_vhci_hc("bye\n");
	return ret;
}
module_init(vhci_init);


static void __exit vhci_cleanup(void)
{
	dbg_vhci_hc("enter\n");

	platform_device_unregister(&the_pdev);
	platform_driver_unregister(&vhci_driver);

	dbg_vhci_hc("bye\n");
}
module_exit(vhci_cleanup);