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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: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This commit is contained in:
Hans de Goede 2013-10-09 17:19:31 +02:00 committed by Sarah Sharp
parent 2fec32b06e
commit bcf7f6e393
2 changed files with 125 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

118
drivers/usb/core/devio.c
View File

@ -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)

7
include/uapi/linux/usbdevice_fs.h
View File

@ -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 */