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Commit bcf7f6e3 authored by Hans de Goede's avatar Hans de Goede Committed by Sarah Sharp
Browse files

usbfs: Add support for allocating / freeing streams 



This allows userspace to use bulk-streams, just like in kernel drivers, see
Documentation/usb/bulk-streams.txt for details on the in kernel API. This
is exported pretty much one on one to userspace.

To use streams an app must first make a USBDEVFS_ALLOC_STREAMS ioctl,
on success this will return the number of streams available (which may be
less then requested). If there are n streams the app can then submit
usbdevfs_urb-s with their stream_id member set to 1-n to use a specific
stream. IE if USBDEVFS_ALLOC_STREAMS returns 4 then stream_id 1-4 can be
used.

When the app is done using streams it should call USBDEVFS_FREE_STREAMS

Note applications are advised to use libusb rather then using the
usbdevfs api directly. The latest version of libusb has support for streams.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent 2fec32b0

drivers/usb/core/devio.c

+118 −0
Original line number Diff line number Diff line
@@ -778,6 +778,79 @@ static struct usb_host_endpoint *ep_to_host_endpoint(struct usb_device *dev, 
		return dev->ep_out[ep & USB_ENDPOINT_NUMBER_MASK];

}



static int parse_usbdevfs_streams(struct dev_state *ps,

				  struct usbdevfs_streams __user *streams,

				  unsigned int *num_streams_ret,

				  unsigned int *num_eps_ret,

				  struct usb_host_endpoint ***eps_ret,

				  struct usb_interface **intf_ret)

{

	unsigned int i, num_streams, num_eps;

	struct usb_host_endpoint **eps;

	struct usb_interface *intf = NULL;

	unsigned char ep;

	int ifnum, ret;



	if (get_user(num_streams, &streams->num_streams) ||

	    get_user(num_eps, &streams->num_eps))

		return -EFAULT;



	if (num_eps < 1 || num_eps > USB_MAXENDPOINTS)

		return -EINVAL;



	/* The XHCI controller allows max 2 ^ 16 streams */

	if (num_streams_ret && (num_streams < 2 || num_streams > 65536))

		return -EINVAL;



	eps = kmalloc(num_eps * sizeof(*eps), GFP_KERNEL);

	if (!eps)

		return -ENOMEM;



	for (i = 0; i < num_eps; i++) {

		if (get_user(ep, &streams->eps[i])) {

			ret = -EFAULT;

			goto error;

		}

		eps[i] = ep_to_host_endpoint(ps->dev, ep);

		if (!eps[i]) {

			ret = -EINVAL;

			goto error;

		}



		/* usb_alloc/free_streams operate on an usb_interface */

		ifnum = findintfep(ps->dev, ep);

		if (ifnum < 0) {

			ret = ifnum;

			goto error;

		}



		if (i == 0) {

			ret = checkintf(ps, ifnum);

			if (ret < 0)

				goto error;

			intf = usb_ifnum_to_if(ps->dev, ifnum);

		} else {

			/* Verify all eps belong to the same interface */

			if (ifnum != intf->altsetting->desc.bInterfaceNumber) {

				ret = -EINVAL;

				goto error;

			}

		}

	}



	if (num_streams_ret)

		*num_streams_ret = num_streams;

	*num_eps_ret = num_eps;

	*eps_ret = eps;

	*intf_ret = intf;



	return 0;



error:

	kfree(eps);

	return ret;

}



static int match_devt(struct device *dev, void *data)

{

	return dev->devt == (dev_t) (unsigned long) data;
@@ -2009,6 +2082,45 @@ static int proc_disconnect_claim(struct dev_state *ps, void __user *arg) 
	return claimintf(ps, dc.interface);

}



static int proc_alloc_streams(struct dev_state *ps, void __user *arg)

{

	unsigned num_streams, num_eps;

	struct usb_host_endpoint **eps;

	struct usb_interface *intf;

	int r;



	r = parse_usbdevfs_streams(ps, arg, &num_streams, &num_eps,

				   &eps, &intf);

	if (r)

		return r;



	destroy_async_on_interface(ps,

				   intf->altsetting[0].desc.bInterfaceNumber);



	r = usb_alloc_streams(intf, eps, num_eps, num_streams, GFP_KERNEL);

	kfree(eps);

	return r;

}



static int proc_free_streams(struct dev_state *ps, void __user *arg)

{

	unsigned num_eps;

	struct usb_host_endpoint **eps;

	struct usb_interface *intf;

	int r;



	r = parse_usbdevfs_streams(ps, arg, NULL, &num_eps, &eps, &intf);

	if (r)

		return r;



	destroy_async_on_interface(ps,

				   intf->altsetting[0].desc.bInterfaceNumber);



	r = usb_free_streams(intf, eps, num_eps, GFP_KERNEL);

	kfree(eps);

	return r;

}



/*

 * NOTE:  All requests here that have interface numbers as parameters

 * are assuming that somehow the configuration has been prevented from
@@ -2185,6 +2297,12 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd, 
	case USBDEVFS_DISCONNECT_CLAIM:

		ret = proc_disconnect_claim(ps, p);

		break;

	case USBDEVFS_ALLOC_STREAMS:

		ret = proc_alloc_streams(ps, p);

		break;

	case USBDEVFS_FREE_STREAMS:

		ret = proc_free_streams(ps, p);

		break;

	}

	usb_unlock_device(dev);

	if (ret >= 0)

include/uapi/linux/usbdevice_fs.h

+7 −0
Original line number Diff line number Diff line
@@ -147,6 +147,11 @@ struct usbdevfs_disconnect_claim { 
	char driver[USBDEVFS_MAXDRIVERNAME + 1];

};



struct usbdevfs_streams {

	unsigned int num_streams; /* Not used by USBDEVFS_FREE_STREAMS */

	unsigned int num_eps;

	unsigned char eps[0];

};



#define USBDEVFS_CONTROL           _IOWR('U', 0, struct usbdevfs_ctrltransfer)

#define USBDEVFS_CONTROL32           _IOWR('U', 0, struct usbdevfs_ctrltransfer32)
@@ -179,5 +184,7 @@ struct usbdevfs_disconnect_claim { 
#define USBDEVFS_RELEASE_PORT      _IOR('U', 25, unsigned int)

#define USBDEVFS_GET_CAPABILITIES  _IOR('U', 26, __u32)

#define USBDEVFS_DISCONNECT_CLAIM  _IOR('U', 27, struct usbdevfs_disconnect_claim)

#define USBDEVFS_ALLOC_STREAMS     _IOR('U', 28, struct usbdevfs_streams)

#define USBDEVFS_FREE_STREAMS      _IOR('U', 29, struct usbdevfs_streams)



#endif /* _UAPI_LINUX_USBDEVICE_FS_H */